Isotope-dilution gas chromatography-mass spectrometry method for the analysis of hydroxyurea.

PubMed

Garg, Uttam; Scott, David; Frazee, Clint; Kearns, Gregory; Neville, Kathleen

2015-06-01

Hydroxyurea is used in the treatment of various malignancies and sickle cell disease. There are limited studies on the pharmacokinetics of hydroxyurea, particularly in pediatric patients. An accurate, precise, and sensitive method is needed to support such studies and to monitor therapeutic adherence. We describe a novel gas chromatography-mass spectrometry (GC-MS) method for the determination of hydroxyurea concentration in plasma using stable labeled hydroxyurea C N2 as an internal standard. The method involved an organic extraction followed by the preparation of trimethylsilyl (TMS) derivatives of hydroxyurea for GC-MS selected ion-monitoring analysis. The following mass-to-charge (m/z) ratio ions for silated hydroxyurea and hydroxyurea C N2 were monitored: hydroxyurea-quantitative ion 277, qualifier ions 292 and 249; hydroxyurea C N2-quantitative ion 280, qualifier ion 295. This method was evaluated for reportable range, accuracy, within-run and between-run imprecisions, and limits of quantification. The reportable range for the method was 0.1-100 mcg/mL. All results were accurate within an allowable error of 15%. Within-run and between-run imprecisions were <15%. Samples were stable for at least 4 hours at room temperature, 2 months at -20°C, and 6 months at -70°C, and after 3 freeze/thaw cycles. Extraction efficiency for 1-, 5-, 10-, and 50-mcg/mL samples averaged 2.2%, 1.8%, 1.6%, and 1.4%, respectively. The isotope-dilution GC-MS method for analysis of hydroxyurea described here is accurate, sensitive, precise, and robust. Its characteristics make the method suitable for supporting pharmacokinetic studies and/or clinical therapeutic monitoring.

Risk of thrombosis according to need of phlebotomies in patients with polycythemia vera treated with hydroxyurea.

PubMed

Alvarez-Larrán, Alberto; Pérez-Encinas, Manuel; Ferrer-Marín, Francisca; Hernández-Boluda, Juan Carlos; Ramírez, María José; Martínez-López, Joaquín; Magro, Elena; Cruz, Yasmina; Mata, María Isabel; Aragües, Pilar; Fox, María Laura; Cuevas, Beatriz; Montesdeoca, Sara; Hernández-Rivas, José Angel; García-Gutiérrez, Valentín; Gómez-Casares, María Teresa; Steegmann, Juan Luis; Durán, María Antonia; Gómez, Montse; Kerguelen, Ana; Bárez, Abelardo; García, Mari Carmen; Boqué, Concepción; Raya, José María; Martínez, Clara; Albors, Manuel; García, Francesc; Burgaleta, Carmen; Besses, Carlos

2017-01-01

Hematocrit control below 45% is associated with a lower rate of thrombosis in polycythemia vera. In patients receiving hydroxyurea, this target can be achieved with hydroxyurea alone or with the combination of hydroxyurea plus phlebotomies. However, the clinical implications of phlebotomy requirement under hydroxyurea therapy are unknown. The aim of this study was to evaluate the need for additional phlebotomies during the first five years of hydroxyurea therapy in 533 patients with polycythemia vera. Patients requiring 3 or more phlebotomies per year (n=85, 16%) showed a worse hematocrit control than those requiring 2 or less phlebotomies per year (n=448, 84%). There were no significant differences between the two study groups regarding leukocyte and platelet counts. Patients requiring 3 or more phlebotomies per year received significantly higher doses of hydroxyurea than the remaining patients. A significant higher rate of thrombosis was found in patients treated with hydroxyurea plus 3 or more phlebotomies per year compared to hydroxyurea with 0-2 phlebotomies per year (20.5% vs. 5.3% at 3 years; P<0.0001). In multivariate analysis, independent risk factors for thrombosis were phlebotomy dependency (HR: 3.3, 95%CI: 1.5-6.9; P=0.002) and thrombosis at diagnosis (HR: 4.7, 95%CI: 2.3-9.8; P<0.0001). The proportion of patients fulfilling the European LeukemiaNet criteria of resistance/intolerance to hydroxyurea was significantly higher in the group requiring 3 or more phlebotomies per year (18.7% vs. 7.1%; P=0.001) mainly due to extrahematologic toxicity. In conclusion, phlebotomy requirement under hydroxyurea therapy identifies a subset of patients with increased proliferation of polycythemia vera and higher risk of thrombosis. Copyright© Ferrata Storti Foundation.

Hydroxyurea-induced oral ulceration.

PubMed

Badawi, Maha; Almazrooa, Soulafa; Azher, Fatima; Alsayes, Fatin

2015-12-01

Hydroxyurea is an antimetabolite that is widely used in the treatment of many benign and malignant conditions. This drug is usually well tolerated but has a number of side effects that vary in incidence. In cases of clinically significant adverse events, hydroxyurea is usually discontinued either temporarily or permanently, depending on treatment need versus harm caused by side effects. Here, we report a case of oral ulceration associated with hydroxyurea treatment in a patient who had chronic myelogenous leukemia. The patient rapidly developed an oral ulcer 12 days after administration of the drug. Hydroxyurea was discontinued, and the oral lesion appreciably decreased in size and severity. Physicians and dentists should be aware of the association between hydroxyurea and oral lesions. Copyright © 2015 Elsevier Inc. All rights reserved.

Immunologic Effects of Hydroxyurea in Sickle Cell Anemia

PubMed Central

Lederman, Howard M.; Connolly, Margaret A.; Kalpatthi, Ram; Ware, Russell E.; Wang, Winfred C.; Luchtman-Jones, Lori; Waclawiw, Myron; Goldsmith, Jonathan C.; Swift, Andrea

2014-01-01

BACKGROUND AND OBJECTIVE: Susceptibility to encapsulated bacteria is well known in sickle cell disease (SCD). Hydroxyurea use is common in adults and children with SCD, but little is known about hydroxyurea’s effects on immune function in SCD. Because hydroxyurea inhibits ribonucleotide reductase, causing cell cycle arrest at the G1–S interface, we postulated that hydroxyurea might delay transition from naive to memory T cells, with inhibition of immunologic maturation and vaccine responses. METHODS: T-cell subsets, naive and memory T cells, and antibody responses to pneumococcal and measles, mumps, and rubella vaccines were measured among participants in a multicenter, randomized, double-blind, placebo-controlled trial of hydroxyurea in infants and young children with SCD (BABY HUG). RESULTS: Compared with placebo, hydroxyurea treatment resulted in significantly lower total lymphocyte, CD4, and memory T-cell counts; however, these numbers were still within the range of historical healthy controls. Antibody responses to pneumococcal vaccination were not affected, but a delay in achieving protective measles antibody levels occurred in the hydroxyurea group. Antibody levels to measles, mumps, and rubella showed no differences between groups at exit, indicating that effective immunization can be achieved despite hydroxyurea use. CONCLUSIONS: Hydroxyurea does not appear to have significant deleterious effects on the immune function of infants and children with SCD. Additional assessments of lymphocyte parameters of hydroxyurea-treated children may be warranted. No changes in current immunization schedules are recommended; however, for endemic disease or epidemics, adherence to accelerated immunization schedules for the measles, mumps, and rubella vaccine should be reinforced. PMID:25180279

Epigenetic and molecular profiles of erythroid cells after hydroxyurea treatment in sickle cell anemia

PubMed Central

Steward, Shirley; Howard, Thad A.; Mortier, Nicole; Smeltzer, Matthew; Wang, Yong-Dong; Ware, Russell E.

2011-01-01

Hydroxyurea has been shown to be efficacious for the treatment of sickle cell anemia (SCA), primarily through the induction of fetal hemoglobin (HbF). However, the exact mechanisms by which hydroxyurea can induce HbF remain incompletely defined, although direct transcriptional effects and altered cell cycle kinetics have been proposed. In this study, we investigated potential epigenetic and alternative molecular mechanisms of hydroxyurea-mediated HbF induction by examining methylation patterns within the Gγ-globin promoter and miRNA expression within primary CD71+ erythrocytes of patients with SCA, both at baseline before beginning hydroxyurea therapy and after reaching maximum tolerated dose (MTD). Using both cross-sectional analysis and paired-sample analysis, we found that the highly methylated Gγ-globin promoter was inversely correlated to baseline HbF levels, but only slightly altered by hydroxyurea treatment. Conversely, expression of several specific miRNAs was significantly increased after hydroxyurea treatment, and expression of miR-26b and miR-151-3p were both associated with HbF levels at MTD. The significant associations identified in these studies suggest that methylation may be important for regulation of baseline HbF, but not after hydroxyurea treatment, whereas changes in miRNA expression may be associated with hydroxyurea-mediated HbF induction. This study was registered at ClinicalTrials.gov (NCT00305175). PMID:21921042

Hydroxyurea effectiveness in children and adolescents with sickle cell anemia: A large retrospective, population-based cohort.

PubMed

Quarmyne, Maa-Ohui; Dong, Wei; Theodore, Rodney; Anand, Sonia; Barry, Vaughn; Adisa, Olufolake; Buchanan, Iris D; Bost, James; Brown, Robert C; Joiner, Clinton H; Lane, Peter A

2017-01-01

The clinical efficacy of hydroxyurea in patients with sickle cell anemia (SCA) has been well established. However, data about its clinical effectiveness in practice is limited. We evaluated the clinical effectiveness of hydroxyurea in a large pediatric population using a retrospective cohort, pre-post treatment study design to control for disease severity selection bias. The cohort included children with SCA (SS, Sβ 0 thalassemia) who received care at Children's Healthcare of Atlanta (CHOA) and who initiated hydroxyurea in 2009-2011. Children on chronic transfusions, or children with inadequate follow up data and/or children who had taken hydroxyurea in the 3 years prior were excluded. For each patient healthcare utilization, laboratory values, and clinical outcomes for the 2-year period prior to hydroxyurea initiation were compared to those 2 years after initiation. Of 211 children with SCA who initiated hydroxyurea in 2009-2011, 134 met eligibility criteria. After initiation of hydroxyurea, rates of hospitalizations, pain encounters, and emergency department visits were reduced by 47% (<0.0001), 36% (P = 0.0001) and 43% (P < 0.0001), respectively. Average hemoglobin levels increased by 0.7 g/dl (P < 0.0001). Hydroxyurea effectiveness was similar across gender, insurance types and age, although there was a slightly greater reduction in hospitalizations in younger children. Am. J. Hematol. 92:77-81, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Hydroxyurea therapy in adult Nigerian sickle cell disease: a monocentric survey on pattern of use, clinical effects and patient's compliance.

PubMed

Adewoyin, Ademola Samson; Oghuvwu, Omokiniovo Sunday; Awodu, Omolade Augustina

2017-03-01

The clinical prospects of hydroxyurea therapy in the management of sickle cell disease (SCD) require evaluation in the Nigerian setting to develop indigenous guidelines. This survey examines the pattern of hydroxyurea therapy, its clinico-haematologic benefits and safety profile in Nigerian SCD subjects. A cross sectional pilot survey was carried out among 60 adult SCD subjects over 3 months. Data on clinical phenotypes, relevant haematological parameters and details of hydroxyurea therapy were obtained using a structured questionnaire through an interview process and case file review. The median age was 30 years. Thirty-four (56.7%) of the subjects are aware of hydroxyurea therapy in SCD. Twenty-four (40%) SCD patients had previously used hydroxyurea. Only 4 subjects were fully compliant. Reasons for non-compliance included poor knowledge and lack of funds. In particular, hydroxyurea reduced leucocyte count and increased mean red cell volume (MCV) in compliant subjects. Hydroxyurea use is low among Nigerian SCD subjects despite its proven efficacy/clinical prospects in the developed nations. Large scale multicenter studies and clinical trials are needed to form a basis for developing standard local treatment protocol for its use.

Acral keratoses and leucocytoclastic vasculitis occurring during treatment of essential thrombocythaemia with hydroxyurea.

PubMed

Worley, B; Glassman, S J

2016-03-01

Hydroxyurea is used in essential thrombocythaemia to lower thromboembolic risk. Cutaneous adverse effects from hydroxyurea are diverse. Small vessel vasculitis has been rarely reported, and the coexistence of several different morphologies has not been described. We report a case of acral keratoses, psoriasiform plaques and leucocytoclastic vasculitis (LCV) in a patient with essential thrombocythaemia. A 69-year-old woman developed a confusing array of skin lesions including keratotic papules, psoriasiform plaques and keratoderma 4 years after commencing hydroxyurea therapy. The initial diagnosis was hand and foot psoriasis, but lesions were resistant to therapy. With an increase in the dose of hydroxyurea, the lesions ulcerated. Skin biopsies taken from different sites indicated different diagnoses, including LCV. Discontinuation of hydroxyurea yielded rapid improvement. Although the most commonly reported cutaneous adverse effect from hydroxyurea is leg ulceration, this can be preceded or accompanied by less dramatic skin lesions. Unless recognized, delayed diagnosis and lesion progression can occur. © 2015 British Association of Dermatologists.

Transcellular movement of hydroxyurea is mediated by specific solute carrier transporters

PubMed Central

Walker, Aisha L.; Franke, Ryan M.; Sparreboom, Alex; Ware, Russell E.

2015-01-01

Objective Hydroxyurea has proven laboratory and clinical therapeutic benefits for sickle cell anemia (SCA) and other diseases, yet many questions remain regarding its in vivo pharmacokinetic and pharmacodynamic profiles. Previous reports suggest that hydroxyurea passively diffuses across cells, but its observed rapid absorption and distribution are more consistent with facilitated or active transport. We investigated the potential role of solute carrier (SLC) transporters in cellular uptake and accumulation of hydroxyurea. Materials and Methods Passive diffusion of hydroxyurea across cell membranes was determined using the parallel artificial membrane permeability assay. SLC transporter screens were conducted using in vitro intracellular drug accumulation and transcellular transport assays in cell lines and oocytes overexpressing SLC transporters. Gene expression of SLC transporters was measured by real-time PCR in human tissues and cell lines. Results Hydroxyurea had minimal diffusion across a lipid bilayer but was a substrate for 5 different SLC transporters belonging to the OCTN and OATP families of transporters and urea transporters A and B. Further characterization of hydroxyurea transport revealed that cellular uptake by OATP1B3 is time and temperature dependent and inhibited by known substrates of OATP1B3. Urea transporters A and B are expressed differentially in human tissues and erythroid cells, and transport hydroxyurea bidirectionally via facilitated diffusion. Conclusions These studies provide new insight into drug transport proteins that may be involved in the in vivo absorption, cellular distribution, and elimination of hydroxyurea. Elucidation of hydroxyurea transcellular movement should improve our understanding of its pharmacokinetics and pharmacodynamics, and may help explain some of the inter-patient drug variability observed in patients with SCA. PMID:21256917

Anagrelide compared with hydroxyurea in essential thrombocythemia: a meta-analysis.

PubMed

Samuelson, Bethany; Chai-Adisaksopha, Chatree; Garcia, David

2015-11-01

Cytoreductive therapy, with or without low-dose aspirin, is the mainstay of thrombotic risk reduction in patients with essential thrombocythemia (ET), but the optimal choice of agent remains unclear. The aim of this study was to meta-analyze currently available data comparing anagrelide to hydroxyurea for reduction of rates of thrombosis, bleeding and death among patients with ET. A literature search for randomized, controlled trials comparing anagrelide to hydroxyurea among patients with ET revealed two published studies. Statistical analysis was performed using fixed effects meta-analysis. Rates of thrombosis were similar between patients treated with hydroxyurea vs anagrelide (RR 0.86, 95 % CI 0.64-1.16). Rates of major bleeding were lower in patients treated with hydroxyurea (RR 0.37, 95 % CI 0.18-0.75). Rates of progression to acute myeloid leukemia were not statistically different (RR 1.50, 95 % CI 0.43-5.29). The composite of thrombosis, major bleeding and death favored hydroxyurea (RR 0.78, 95 % CI 0.63-0.97). In conclusion, our analysis supports use of hydroxyurea as a first-line cytoreductive agent for patients with ET, based largely on decreased rates of major bleeding. Anagrelide appears to be equally effective for protection against thrombotic events and may be an appropriate alternative for patients who are intolerant of hydroxyurea.

How I use hydroxyurea to treat young patients with sickle cell anemia

PubMed Central

2010-01-01

Hydroxyurea has many characteristics of an ideal drug for sickle cell anemia (SCA) and provides therapeutic benefit through multiple mechanisms of action. Over the past 25 years, substantial experience has accumulated regarding its safety and efficacy for patients with SCA. Early proof-of-principle studies were followed by prospective phase 1/2 trials demonstrating efficacy in affected adults, then adolescents and children, and more recently infants and toddlers. The phase 3 National Heart, Lung and Blood Institute–sponsored Multicenter Study of Hydroxyurea trial proved clinical efficacy for preventing acute vaso-occlusive events in severely affected adults. Based on this cumulative experience, hydroxyurea has emerged as an important therapeutic option for children and adolescents with recurrent vaso-occlusive events; recent evidence documents sustained long-term benefits with prevention or reversal of chronic organ damage. Despite abundant evidence for its efficacy, however, hydroxyurea has not yet translated into effective therapy for SCA. Because many healthcare providers have inadequate knowledge about hydroxyurea, patients and families are not offered treatment or decline because of unrealistic fears. Limited support for hydroxyurea by lay organizations and inconsistent medical delivery systems also contribute to underuse. Although questions remain regarding its long-term risks and benefits, current evidence suggests that many young patients with SCA should receive hydroxyurea treatment. PMID:20223921

Pharmacokinetics, pharmacodynamics, and pharmacogenetics of hydroxyurea treatment for children with sickle cell anemia

PubMed Central

Despotovic, Jenny M.; Mortier, Nicole A.; Flanagan, Jonathan M.; He, Jin; Smeltzer, Matthew P.; Kimble, Amy C.; Aygun, Banu; Wu, Song; Howard, Thad; Sparreboom, Alex

2011-01-01

Hydroxyurea therapy has proven laboratory and clinical efficacies for children with sickle cell anemia (SCA). When administered at maximum tolerated dose (MTD), hydroxyurea increases fetal hemoglobin (HbF) to levels ranging from 10% to 40%. However, interpatient variability of percentage of HbF (%HbF) response is high, MTD itself is variable, and accurate predictors of hydroxyurea responses do not currently exist. HUSTLE (NCT00305175) was designed to provide first-dose pharmacokinetics (PK) data for children with SCA initiating hydroxyurea therapy, to investigate pharmacodynamics (PD) parameters, including HbF response and MTD after standardized dose escalation, and to evaluate pharmacogenetics influences on PK and PD parameters. For 87 children with first-dose PK studies, substantial interpatient variability was observed, plus a novel oral absorption phenotype (rapid or slow) that influenced serum hydroxyurea levels and total hydroxyurea exposure. PD responses in 174 subjects were robust and similar to previous cohorts; %HbF at MTD was best predicted by 5 variables, including baseline %HbF, whereas MTD was best predicted by 5 variables, including serum creatinine. Pharmacogenetics analysis showed single nucleotide polymorphisms influencing baseline %HbF, including 5 within BCL11A, but none influencing MTD %HbF or dose. Accurate prediction of hydroxyurea treatment responses for SCA remains a worthy but elusive goal. PMID:21876119

Hydroxyurea for sickle cell anemia: What have we learned and what questions still remain?

PubMed Central

McGann, Patrick T.; Ware, Russell E.

2011-01-01

Purpose of review Sickle cell anemia (SCA) is a well-characterized severe hematological disorder with substantial morbidity and early mortality. Hydroxyurea is a potent inducer of fetal hemoglobin, and evidence over the past 25 years has documented its laboratory and clinical efficacy for both adults and children with SCA. Recent findings The Phase III study of hydroxyurea in infants (BABY HUG) has just been completed and preliminary results indicate equivocal benefits for organ protection during the two-year treatment period, but significant benefits for pain, acute chest syndrome, hospitalizations, and transfusions. Three new reports document the benefits of hydroxyurea on reducing mortality in SCA: two adult trials (LaSHS and MSH) and one pediatric study (Brazilian cohort). Recent results from the HUSTLE protocol suggest minimal genotoxicity or carcinogenicity with long-term hydroxyurea exposure. Summary The potential utility of hydroxyurea for all patients with SCA is clear and indisputable. With decades of accumulated evidence and documented efficacy with an acceptable long-term safety profile, it is time to consider hydroxyurea treatment the standard of care for all young patients with SCA. Exporting our knowledge and experience with hydroxyurea to developing nations with large medical burdens from SCA can help relieve global suffering from this condition. PMID:21372708

A predictable but life-threatening complication of hydroxyurea in a patient with sickle cell anaemia: an experience learned from a Jehovah's Witness.

PubMed

Tun, Aung Myint; Naing, Ei Ei; Tun, Nay Min; Guevara, Elizabeth

2015-09-30

It is well known that hydroxyurea can cause pancytopaenia secondary to bone marrow suppression, which is reversible with short-term discontinuation of the therapy. However, it is important to note that bone marrow suppressive effects caused by hydroxyurea could be easily potentiated in patients with sickle cell anaemia complicated by chronic kidney disease (CKD). We present a case of a Jehovah's Witness with sickle cell anaemia, who developed severe bone marrow suppression due to the combined effects of hydroxyurea and CKD, resulting in a prolonged recovery period after discontinuation of hydroxyurea. 2015 BMJ Publishing Group Ltd.

Adherence to hydroxyurea, health-related quality of life domains, and patients' perceptions of sickle cell disease and hydroxyurea: a cross-sectional study in adolescents and young adults.

PubMed

Badawy, Sherif M; Thompson, Alexis A; Lai, Jin-Shei; Penedo, Frank J; Rychlik, Karen; Liem, Robert I

2017-07-05

Sickle cell disease (SCD) patients have impaired domains of health-related quality of life (HRQOL). Hydroxyurea is safe and efficacious in SCD; however, adherence is suboptimal, and patients' perceptions are poorly understood amongst adolescents and young adults (AYA). Study objectives were to: (1) examine patients' perceptions of SCD and hydroxyurea; and (2) explore the relationship of their perceptions to clinical characteristics, HRQOL domains and hydroxyurea adherence. Thirty-four SCD patients on hydroxyurea (≥6 months) participated in a single-institution study. Study measures included Brief-Illness Perceptions Questionnaire, ©Modified Morisky Adherence Scale 8-items, and Patient Reported Outcomes Measurement Information System (PROMIS®). We assessed the relationship of patients' perceptions to hydroxyurea adherence using Wilcoxon rank-sum test, the number of hospitalizations using Kruskal-Wallis test, and the number of ED visits, adherence level, HRQOL domain scores using Spearman's rho correlations. We conducted a sub-analysis in HbSS patients to evaluate the relationship of patients' perceptions to laboratory markers of hydroxyurea adherence. Participants were 59% male and 91% Black, and had a median age of 13.5 (range 12-18) years. Participants with ≥4 hospitalizations over 1-year prior (using electronic medical chart review) reported more negative perceptions of SCD-related symptoms and emotional response, and perceived hydroxyurea as less beneficial; all p-values ≤0.01. Most participants (74%) reported low hydroxyurea adherence. Participants with higher hydroxyurea adherence perceived more hydroxyurea benefits (r s  = 0.44, p < 0.01) and had better emotional response to SCD (r s  = -0.44, p = 0.01). In a sub-analysis of HbSS patients, perceived benefits of hydroxyurea positively correlated with HbF (r s  = 0.37, p = 0.05) and MCV values (r s  = 0.35, p = 0.05). Participants with more negative perceptions of SCD-related consequences, concerns, and emotional response, and fewer perceived hydroxyurea benefits reported worse fatigue (r s  = 0.68; r s  = 0.44; r s  = 0.74; r s  = -0.60), pain (r s  = 0.56; r s  = 0.54; r s  = 0.63; r s  = -0.39), anxiety (r s  = 0.55; r s  = 0.58; r s  = 0.56; r s  = -0.47), and depression (r s  = 0.64; r s  = 0.49; r s  = 0.70; r s  = -0.62), respectively, all p-values <0.05. Dynamics influencing hydroxyurea adherence are multifactorial, and understanding patients' perceptions is critical to overcoming adherence barriers. Patients' favorable perceptions correlated with greater adherence and better HRQOL domain scores. Prospective evaluation of patients' perceptions of SCD and hydroxyurea in relation adherence, HRQOL domains and clinical outcomes is warranted.

Effect of Hydroxyurea on Staphylococcus epidermidis and Micrococcus lysodeikticus: Thickening of the Cell Wall

PubMed Central

Feiner, Rose R.; Coward, Joe E.; Rosenkranz, Herbert S.

1973-01-01

Hydroxyurea-sensitive strains of Staphylococcus epidermidis and Micrococcus lysodeikticus showed marked thickening of cell walls and reduction in deoxyribonucleic acid synthesis when grown in the presence of hydroxyurea. Images PMID:4790602

Macrocytosis secondary to hydroxyurea therapy.

PubMed

Conrado, Francisco O; Weeden, Amy L; Speas, Abbie L; Leissinger, Mary K

2017-09-01

A 10-year-old, male neutered Shetland Sheepdog was presented to the University of Florida for evaluation of a well-granulated mast cell tumor. Hydroxyurea therapy was instituted and serial CBCs showed persistent mild anemia and macrocytosis without a corresponding increase in polychromasia. The dog's MCV increased progressively, reaching its highest value of 100.0 fL after 6 months of treatment, and a diagnosis of macrocytosis associated with hydroxyurea therapy was made. The dog's increase in MCV was prominent, and rapidly decreased after the drug was discontinued, consistent with previous observations in human and canine subjects treated with hydroxyurea. Hydroxyurea is a cytotoxic chemotherapeutic agent used in a variety of conditions in human and veterinary medicine, and megaloblastic changes associated with its use have been described in multiple species. This report shows that hydroxyurea treatment is a differential diagnosis for prominent macrocytosis in dogs in the absence of other signs of erythrocyte regeneration. © 2017 American Society for Veterinary Clinical Pathology.

Hydroxyurea is associated with lower costs of care of young children with sickle cell anemia.

PubMed

Wang, Winfred C; Oyeku, Suzette O; Luo, Zhaoyu; Boulet, Sheree L; Miller, Scott T; Casella, James F; Fish, Billie; Thompson, Bruce W; Grosse, Scott D

2013-10-01

In the BABY HUG trial, young children with sickle cell anemia randomized to receive hydroxyurea had fewer episodes of pain, hospitalization, and transfusions. With anticipated broader use of hydroxyurea in this population, we sought to estimate medical costs of care in treated versus untreated children. The BABY HUG database was used to compare inpatient events in subjects receiving hydroxyurea with those receiving placebo. Unit costs were estimated from the 2009 MarketScan Multi-state Medicaid Database for children with sickle cell disease, aged 1 to 3 years. Inpatient costs were based on length of hospital stay, modified by the occurrence of acute chest syndrome, splenic sequestration, or transfusion. Outpatient expenses were based on the schedule required for BABY HUG and a "standard" schedule for 1- to 3-year-olds with sickle cell anemia. There were 232 hospitalizations in the subjects receiving hydroxyurea and 324 in those on placebo; length of hospital stay was similar in the 2 groups. Estimated outpatient expenses were greater in those receiving hydroxyurea, but these were overshadowed by inpatient costs. The total estimated annual cost for those on hydroxyurea ($11 072) was 21% less than the cost of those on placebo ($13 962; P = .038). Savings on inpatient care resulted in a significantly lower overall estimated medical care cost for young children with sickle cell anemia who were receiving hydroxyurea compared with those receiving placebo. Because cost savings are likely to increase with age, these data provide additional support for broad use of hydroxyurea treatment in this population.

Effects of hydroxyurea treatment for patients with hemoglobin SC disease.

PubMed

Luchtman-Jones, Lori; Pressel, Sara; Hilliard, Lee; Brown, R Clark; Smith, Mary G; Thompson, Alexis A; Lee, Margaret T; Rothman, Jennifer; Rogers, Zora R; Owen, William; Imran, Hamayun; Thornburg, Courtney; Kwiatkowski, Janet L; Aygun, Banu; Nelson, Stephen; Roberts, Carla; Gauger, Cynthia; Piccone, Connie; Kalfa, Theodosia; Alvarez, Ofelia; Hassell, Kathryn; Davis, Barry R; Ware, Russell E

2016-02-01

Although hemoglobin SC (HbSC) disease is usually considered less severe than sickle cell anemia (SCA), which includes HbSS and HbS/β(0) -thalassemia genotypes, many patients with HbSC experience severe disease complications, including vaso-occlusive pain, acute chest syndrome, avascular necrosis, retinopathy, and poor quality of life. Fully 20 years after the clinical and laboratory efficacy of hydroxyurea was proven in adult SCA patients, the safety and utility of hydroxyurea treatment for HbSC patients remain unclear. Recent NHLBI evidence-based guidelines highlight this as a critical knowledge gap, noting HbSC accounts for ∼30% of sickle cell patients within the United States. To date, only 5 publications have reported short-term, incomplete, or conflicting laboratory and clinical outcomes of hydroxyurea treatment in a total of 71 adults and children with HbSC. We now report on a cohort of 133 adult and pediatric HbSC patients who received hydroxyurea, typically for recurrent vaso-occlusive pain. Hydroxyurea treatment was associated with a stable hemoglobin concentration; increased fetal hemoglobin (HbF) and mean corpuscular volume (MCV); and reduced white blood cell count (WBC), absolute neutrophil count (ANC), and absolute reticulocyte count (ARC). Reversible cytopenias occurred in 22% of patients, primarily neutropenia and thrombocytopenia. Painful events were reduced with hydroxyurea, more in patients >15 years old. These multicenter data support the safety and potentially salutary effects of hydroxyurea treatment for HbSC disease; however, a multicenter, placebo-controlled, Phase 3 clinical trial is needed to determine if hydroxyurea therapy has efficacy for patients with HbSC disease. © 2015 Wiley Periodicals, Inc.

Deprenyl Enhances the Teratogenicity of Hydroxyurea in Organogenesis Stage Mouse Embryos

PubMed Central

Schlisser, Ava E.; Hales, Barbara F.

2013-01-01

Hydroxyurea, an antineoplastic drug, is a model teratogen. The administration of hydroxyurea to CD1 mice on gestation day 9 induces oxidative stress, increasing the formation of 4-hydroxy-2-nonenal adducts to redox-sensitive proteins such as glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in the caudal region of the embryo. GAPDH catalytic activity is reduced, and its translocation into the nucleus is increased. Because the nuclear translocation of GAPDH is associated with oxidative stress–induced cell death, we hypothesized that this translocation plays a role in mediating the teratogenicity of hydroxyurea. Deprenyl (also known as selegiline), a drug used as a neuroprotectant in Parkinson’s disease, inhibits the nuclear translocation of GAPDH. Hence, timed pregnant CD1 mice were treated with deprenyl (10mg/kg) on gestation day 9 followed by the administration of hydroxyurea (400 or 600mg/kg). Deprenyl treatment significantly decreased the hydroxyurea-induced nuclear translocation of GAPDH in the caudal lumbosacral somites. Deprenyl enhanced hydroxyurea-mediated caudal malformations, inducing specifically limb reduction, digit anomalies, tail defects, and lumbosacral vertebral abnormalities. Deprenyl did not augment the hydroxyurea-induced inhibition of glycolysis or alter the ratio of oxidized to reduced glutathione. However, it did dramatically increase cleaved caspase-3 in embryos. These data suggest that nuclear GAPDH plays an important, region-specific, role in teratogen-exposed embryos. Deprenyl exacerbated the developmental outcome of hydroxyurea exposure by a mechanism that is independent of oxidative stress. Although the administration of deprenyl alone did not affect pregnancy outcome, this drug may have adverse consequences when combined with exposures that increase the risk of malformations. PMID:23696560

Hydroxyurea Is Associated With Lower Costs of Care of Young Children With Sickle Cell Anemia

PubMed Central

Oyeku, Suzette O.; Luo, Zhaoyu; Boulet, Sheree L.; Miller, Scott T.; Casella, James F.; Fish, Billie; Thompson, Bruce W.; Grosse, Scott D.

2013-01-01

BACKGROUND AND OBJECTIVE: In the BABY HUG trial, young children with sickle cell anemia randomized to receive hydroxyurea had fewer episodes of pain, hospitalization, and transfusions. With anticipated broader use of hydroxyurea in this population, we sought to estimate medical costs of care in treated versus untreated children. METHODS: The BABY HUG database was used to compare inpatient events in subjects receiving hydroxyurea with those receiving placebo. Unit costs were estimated from the 2009 MarketScan Multi-state Medicaid Database for children with sickle cell disease, aged 1 to 3 years. Inpatient costs were based on length of hospital stay, modified by the occurrence of acute chest syndrome, splenic sequestration, or transfusion. Outpatient expenses were based on the schedule required for BABY HUG and a “standard” schedule for 1- to 3-year-olds with sickle cell anemia. RESULTS: There were 232 hospitalizations in the subjects receiving hydroxyurea and 324 in those on placebo; length of hospital stay was similar in the 2 groups. Estimated outpatient expenses were greater in those receiving hydroxyurea, but these were overshadowed by inpatient costs. The total estimated annual cost for those on hydroxyurea ($11 072) was 21% less than the cost of those on placebo ($13 962; P = .038). CONCLUSIONS: Savings on inpatient care resulted in a significantly lower overall estimated medical care cost for young children with sickle cell anemia who were receiving hydroxyurea compared with those receiving placebo. Because cost savings are likely to increase with age, these data provide additional support for broad use of hydroxyurea treatment in this population. PMID:23999955

Massive Accidental Overdose of Hydroxyurea in a Young Child with Sickle Cell Anemia

PubMed Central

Miller, Scott T.; Rey, Kathy; He, Jin; Flanagan, Jonathan; Fish, Billie J.; Rogers, Zora R.; Wang, Winfred C.; Ware, Russell E.

2011-01-01

The Pediatric Hydroxyurea Phase III Clinical Trial (BABY HUG) confirmed safety and efficacy of hydroxyurea therapy for infants with sickle cell anemia. Treatment was associated with reduction in rates of pain, acute chest syndrome, hospitalizations and blood transfusions; improved hematologic values; and, perhaps, preservation of organ function. During the study, a two year-old ingested at one time an entire 35-day supply of hydroxyurea (612 mg/kg body-weight). Despite a serum level of 7,756 μM four hours post-ingestion, the only toxicity was transient mild myelosuppression. With wider usage of hydroxyurea anticipated, conservative management of future overdoses seems reasonable. (ClinicalTrials.gov NCT00006400) PMID:21744485

Analysis of oxidative status and biochemical parameters in adult patients with sickle cell anemia treated with hydroxyurea, Ceará, Brazil

PubMed Central

Teixeira Neto, Paulo Florentino; Gonçalves, Romélia Pinheiro; Elias, Darcielle Bruna Dias; de Araújo, Cleiton Pinheiro; Magalhães, Hemerson Iury Ferreira

2011-01-01

Background Sickle cell anemia is a hemoglobinopathy caused by a mutation that results in the production of an abnormal hemoglobin molecule, hemoglobin S (Hb S). This is responsible for profound physiological changes, such as the sickling of red blood cells. Several studies have shown that hydroxyurea protects against vaso-occlusive crises. Objective The aim of this study was to evaluate the oxidative stress associated with biochemical parameters in patients with sickle cell anemia treated with hydroxyurea. Methods The study was conducted with 20 male and 25 female patients at the Hospital Universitário Walter Cantídio. The patients were divided into two groups: a study group (n = 12), patients with sickle cell anemia who were receiving hydroxyurea and a control group (n = 33) of sickle cell anemia patients not submitted to hydroxyurea treatment. The biochemical parameters analyzed were ferritin, transferrin, and serum iron. Glutathione was measured in its reduced form to analyze the oxidative state. Results The results showed insignificant increases in the levels of serum iron, transferrin and ferritin in patients treated with hydroxyurea when compared with those who did not take the medication. However, the glutathione levels were significantly higher in patients taking hydroxyurea than in controls. Conclusions These results indicate that hydroxyurea possibly acts as an antioxidant by increasing glutathione levels. PMID:23049297

Hydroxyurea responses in clinically varied beta, HbE-beta thalassaemia and sickle cell anaemia patients of Eastern India.

PubMed

Chatterjee, Tridip; Chakravarty, Amit; Chakravarty, Sudipa

2018-05-01

The haematological and clinical response to hydroxyurea was estimated in HbE-beta, beta thalassaemia and sickle cell anaemia patients of Eastern India, with variable clinical severity and transfusion requirement to determine whether hydroxyurea can help these patients to maintain their steady haemoglobin level without blood transfusions. Three hundred patients (189 HbE-beta thalassaemia, 95 beta thalassaemia and 16 other haemoglobinopathies including sickle cell anaemia) were selected for hydroxyurea therapy and were followed up for 48-60 months. Results suggest significant response to hydroxyurea therapy in 19 beta and 99 HbE-beta patients in the transfusion-dependent group (GR-I). All of them became transfusion-independent while on hydroxyurea therapy. The majority of responding patients were IVS1-5(G-C) in one of their alleles in HbE-beta cases (83 out of 119). Though IVS1-5(G-C) was found to be the commonest mutation in our selected patients, the mutational background of the patients does not found to have any significant correlation with the response category towards hydroxyurea as per the results observed in our study. But, the drug works pretty well in most of the transfusion-dependent patients, as these patients were withdrawn from regular blood transfusion. At the same time, partial or no response to the drug hydroxyurea was also recorded in our study.

Original Research: Parvovirus B19 infection in children with sickle cell disease in the hydroxyurea era

PubMed Central

Penkert, Rhiannon R; Lavoie, Paul; Tang, Li; Sun, Yilun; Hurwitz, Julia L

2016-01-01

Parvovirus B19 infection causes transient aplastic crisis in sickle cell disease (SCD) due to a temporary interruption in the red blood cell production. Toxicity from hydroxyurea includes anemia and reticulocytopenia, both of which also occur during a transient aplastic crisis event. Hydroxyurea inhibits proliferation of hematopoietic cells and may be immunosuppressive. We postulated that hydroxyurea could exacerbate parvovirus B19-induced aplastic crisis and inhibit the development of specific immune responses in children with SCD. We conducted a retrospective review of parvovirus B19 infection in 330 children with SCD. Altogether there were 120 known cases of aplastic crisis attributed to parvovirus B19 infection, and 12% of children were on hydroxyurea treatment during the episode. We evaluated hematological and immune responses. Children with HbSS or HbSβ0-thalassemia treated with hydroxyurea, when compared with untreated children, required fewer transfusions and had higher Hb concentration nadir during transient aplastic crisis. Duration of hospital stays was no different between hydroxyurea-treated and untreated groups. Children tested within a week following aplastic crisis were positive for parvovirus-specific IgG. Immune responses lasted for the duration of the observation period, up to 13 years after transient aplastic crisis, and there were no repeat aplastic crisis episodes. The frequencies of parvovirus-specific antibodies in all children with SCD increased with age, as expected due to the increased likelihood of a parvovirus exposure, and were comparable to frequencies reported for healthy children. Approximately one-third of children had a positive parvovirus B19-specific IgG test without a documented history of transient aplastic crisis, and 64% of them were treated with hydroxyurea. Hydroxyurea may reduce requirements for blood transfusions and may attenuate symptoms during transient aplastic crisis episodes caused by parvovirus B19 infections. Children with SCD, whether treated or untreated with hydroxyurea, generate sustained and protective parvovirus B19-specific immune responses. PMID:26940953

Original Research: Parvovirus B19 infection in children with sickle cell disease in the hydroxyurea era.

PubMed

Hankins, Jane S; Penkert, Rhiannon R; Lavoie, Paul; Tang, Li; Sun, Yilun; Hurwitz, Julia L

2016-04-01

Parvovirus B19 infection causes transient aplastic crisis in sickle cell disease (SCD) due to a temporary interruption in the red blood cell production. Toxicity from hydroxyurea includes anemia and reticulocytopenia, both of which also occur during a transient aplastic crisis event. Hydroxyurea inhibits proliferation of hematopoietic cells and may be immunosuppressive. We postulated that hydroxyurea could exacerbate parvovirus B19-induced aplastic crisis and inhibit the development of specific immune responses in children with SCD. We conducted a retrospective review of parvovirus B19 infection in 330 children with SCD. Altogether there were 120 known cases of aplastic crisis attributed to parvovirus B19 infection, and 12% of children were on hydroxyurea treatment during the episode. We evaluated hematological and immune responses. Children with HbSS or HbSβ(0)-thalassemia treated with hydroxyurea, when compared with untreated children, required fewer transfusions and had higher Hb concentration nadir during transient aplastic crisis. Duration of hospital stays was no different between hydroxyurea-treated and untreated groups. Children tested within a week following aplastic crisis were positive for parvovirus-specific IgG. Immune responses lasted for the duration of the observation period, up to 13 years after transient aplastic crisis, and there were no repeat aplastic crisis episodes. The frequencies of parvovirus-specific antibodies in all children with SCD increased with age, as expected due to the increased likelihood of a parvovirus exposure, and were comparable to frequencies reported for healthy children. Approximately one-third of children had a positive parvovirus B19-specific IgG test without a documented history of transient aplastic crisis, and 64% of them were treated with hydroxyurea. Hydroxyurea may reduce requirements for blood transfusions and may attenuate symptoms during transient aplastic crisis episodes caused by parvovirus B19 infections. Children with SCD, whether treated or untreated with hydroxyurea, generate sustained and protective parvovirus B19-specific immune responses. © 2016 by the Society for Experimental Biology and Medicine.

[Hydroxyurea (hydroxycarbamide)-induced hepatic dysfunction confirmed by drug-induced lymphocyte stimulation test].

PubMed

Shimizu, Takayuki; Mori, Takehiko; Karigane, Daiki; Kikuchi, Taku; Koda, Yuya; Toyama, Takaaki; Nakajima, Hideaki; Okamoto, Shinichiro

2014-01-01

A 62-year-old man with refractory leukemia transformed from myelodysplastic syndrome was placed on hydroxyurea (hydroxycarbamide) at a daily dose of 500 mg. Because of insufficient cytoreductive efficacy, the dose was increased to 1,500 mg five days later. Eight days after the initiation of hydroxyurea, the patient started complaining of chills, fever, and vomiting. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were markedly elevated to 5,098 and 3,880 IU/l from 44 and 59 IU/l in one day, respectively. Tests for hepatitis viruses were all negative. With the discontinuation of hydroxyurea, AST and ALT returned to their former levels within two weeks. A drug-induced lymphocyte stimulation test for hydroxyurea was positive with a stimulating index of 2.0. Hepatic dysfunction has been recognized as one of the side effects of hydroxyurea. However, there have been only a limited number of reports demonstrating drug allergy to have a role in hepatic dysfunction accompanied by fever and gastrointestinal symptoms. The findings of our case strongly suggest that all presentations could be explained by drug allergy. Physicians should be mindful of the potential for acute and severe hepatic dysfunction due to allergic reaction against hydroxyurea.

Hydroxyurea is associated with lower prevalence of albuminuria in adults with sickle cell disease

PubMed Central

Laurin, Louis-Philippe; Nachman, Patrick H.; Desai, Payal C.; Ataga, Kenneth I.; Derebail, Vimal K.

2014-01-01

Background Albuminuria is an early manifestation of sickle cell nephropathy. Prior small case series suggests benefit of hydroxyurea in reducing albuminuria, with a similar trend noted in pediatric studies. We aimed to comprehensively evaluate hydroxyurea use and prevalence of albuminuria in adult sickle cell patients. Methods We performed a cross-sectional study of 149 adult patients followed between 2000 and 2011 in a comprehensive sickle cell clinic. All patients were assessed for albuminuria either by direct measurement or by urinary chemical strip (dipstick) testing. Urinary albumin-to-creatinine ratios (UACRs) were available for 112 patients. Hydroxyurea exposure was defined as ≥3 months of therapy before the assessment of albuminuria. Albuminuria was defined as either UACR ≥30 mg/g or ≥1+ proteinuria on two separate dipsticks. We constructed a multivariate logistic regression model to assess the association between hydroxyurea and albuminuria. Results The prevalence of albuminuria was lower among patients on hydroxyurea (34.7 versus 55.4%; P = 0.01) as was median albumin excretion (17.9 versus 40.5 mg/g; P = 0.04). In multivariate analysis, hydroxyurea was associated with a lower likelihood of albuminuria (odds ratio 0.28, 95% CI: 0.11–0.75, P = 0.01), adjusting for age, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use, tricuspid regurgitant jet velocity, hypertension and acute chest syndrome. Conclusions In our population of sickle cell patients, those using hydroxyurea were less than one-third as likely to exhibit albuminuria. Hydroxyurea use may prevent development of overt nephropathy or the progression of sickle cell disease nephropathy to end-stage renal disease, and its use for this indication merits further investigation. PMID:24084325

Hydroxyurea is associated with lower prevalence of albuminuria in adults with sickle cell disease.

PubMed

Laurin, Louis-Philippe; Nachman, Patrick H; Desai, Payal C; Ataga, Kenneth I; Derebail, Vimal K

2014-06-01

Albuminuria is an early manifestation of sickle cell nephropathy. Prior small case series suggests benefit of hydroxyurea in reducing albuminuria, with a similar trend noted in pediatric studies. We aimed to comprehensively evaluate hydroxyurea use and prevalence of albuminuria in adult sickle cell patients. We performed a cross-sectional study of 149 adult patients followed between 2000 and 2011 in a comprehensive sickle cell clinic. All patients were assessed for albuminuria either by direct measurement or by urinary chemical strip (dipstick) testing. Urinary albumin-to-creatinine ratios (UACRs) were available for 112 patients. Hydroxyurea exposure was defined as ≥3 months of therapy before the assessment of albuminuria. Albuminuria was defined as either UACR ≥30 mg/g or ≥1+ proteinuria on two separate dipsticks. We constructed a multivariate logistic regression model to assess the association between hydroxyurea and albuminuria. The prevalence of albuminuria was lower among patients on hydroxyurea (34.7 versus 55.4%; P = 0.01) as was median albumin excretion (17.9 versus 40.5 mg/g; P = 0.04). In multivariate analysis, hydroxyurea was associated with a lower likelihood of albuminuria (odds ratio 0.28, 95% CI: 0.11-0.75, P = 0.01), adjusting for age, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use, tricuspid regurgitant jet velocity, hypertension and acute chest syndrome. In our population of sickle cell patients, those using hydroxyurea were less than one-third as likely to exhibit albuminuria. Hydroxyurea use may prevent development of overt nephropathy or the progression of sickle cell disease nephropathy to end-stage renal disease, and its use for this indication merits further investigation. © The Author 2013. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Blood transfusion versus hydroxyurea in beta-thalassemia in Iran: a cost-effectiveness study.

PubMed

Ravangard, Ramin; Mirzaei, Zahra; Keshavarz, Khosro; Haghpanah, Sezaneh; Karimi, Mehran

2017-11-21

Thalassemia intermedia is a type of anemia which has several treatments modalities. We aimed to study the cost effectiveness of two treatments, including blood transfusion and hydroxyurea, in patients with beta-thalassemia intermedia in south of Iran referred to a referral center affiliated to Iran, Shiraz University of Medical Sciences in 2015. This was a cost-effectiveness study which was conducted on 122 patients with beta-thalassemia intermedia. The indicator of effectiveness in this study was the reduction of growth disorder (normal BMI). Data analysis was done using SPSS 21, Excel 2010 and Treeage 2011. Finally, the one-way sensitivity analysis was performed to determine the robustness of the results. The average annual costs of blood transfusion and the use of hydroxyurea in 2015 were 20733.27 purchasing power parity (PPP)$ and 7040.29 PPP$, respectively. The effectiveness of blood transfusion was57.4% while in hydroxyurea group was 60.7%. The results showed that the cost effectiveness of using hydroxyurea was more than that of blood transfusion. Therefore, it is recommended that the use of hydroxyurea in the treatment of patients with beta-thalassemia intermedia would become the first priority, and more basic and supplementary insurance coverage for treating such patients using hydroxyurea should be considered.

Widespread Natural Occurrence of Hydroxyurea in Animals.

PubMed

Fraser, David I; Liu, Kyle T; Reid, Bryan J; Hawkins, Emily; Sevier, Andrew; Pyle, Michelle; Robinson, Jacob W; Ouellette, Pierre H R; Ballantyne, James S

2015-01-01

Here we report the widespread natural occurrence of a known antibiotic and antineoplastic compound, hydroxyurea in animals from many taxonomic groups. Hydroxyurea occurs in all the organisms we have examined including invertebrates (molluscs and crustaceans), fishes from several major groups, amphibians and mammals. The species with highest concentrations was an elasmobranch (sharks, skates and rays), the little skate Leucoraja erinacea with levels up to 250 μM, high enough to have antiviral, antimicrobial and antineoplastic effects based on in vitro studies. Embryos of L. erinacea showed increasing levels of hydroxyurea with development, indicating the capacity for hydroxyurea synthesis. Certain tissues of other organisms (e.g. skin of the frog (64 μM), intestine of lobster (138 μM) gills of the surf clam (100 μM)) had levels high enough to have antiviral effects based on in vitro studies. Hydroxyurea is widely used clinically in the treatment of certain human cancers, sickle cell anemia, psoriasis, myeloproliferative diseases, and has been investigated as a potential treatment of HIV infection and its presence at high levels in tissues of elasmobranchs and other organisms suggests a novel mechanism for fighting disease that may explain the disease resistance of some groups. In light of the known production of nitric oxide from exogenously applied hydroxyurea, endogenous hydoxyurea may play a hitherto unknown role in nitric oxide dynamics.

Widespread Natural Occurrence of Hydroxyurea in Animals

PubMed Central

Fraser, David I.; Liu, Kyle T.; Reid, Bryan J.; Hawkins, Emily; Sevier, Andrew; Pyle, Michelle; Robinson, Jacob W.; Ouellette, Pierre H. R.; Ballantyne, James S.

2015-01-01

Here we report the widespread natural occurrence of a known antibiotic and antineoplastic compound, hydroxyurea in animals from many taxonomic groups. Hydroxyurea occurs in all the organisms we have examined including invertebrates (molluscs and crustaceans), fishes from several major groups, amphibians and mammals. The species with highest concentrations was an elasmobranch (sharks, skates and rays), the little skate Leucoraja erinacea with levels up to 250 μM, high enough to have antiviral, antimicrobial and antineoplastic effects based on in vitro studies. Embryos of L. erinacea showed increasing levels of hydroxyurea with development, indicating the capacity for hydroxyurea synthesis. Certain tissues of other organisms (e.g. skin of the frog (64 μM), intestine of lobster (138 μM) gills of the surf clam (100 μM)) had levels high enough to have antiviral effects based on in vitro studies. Hydroxyurea is widely used clinically in the treatment of certain human cancers, sickle cell anemia, psoriasis, myeloproliferative diseases, and has been investigated as a potential treatment of HIV infection and its presence at high levels in tissues of elasmobranchs and other organisms suggests a novel mechanism for fighting disease that may explain the disease resistance of some groups. In light of the known production of nitric oxide from exogenously applied hydroxyurea, endogenous hydoxyurea may play a hitherto unknown role in nitric oxide dynamics. PMID:26600157

Hydroxyurea Use in Young Children With Sickle Cell Anemia in New York State.

PubMed

Anders, David G; Tang, Fei; Ledneva, Tatania; Caggana, Michele; Green, Nancy S; Wang, Ying; Sturman, Lawrence S

2016-07-01

This study examined hydroxyurea usage in young children with sickle cell anemia within New York State (NYS). The cohort was 273 children with sickle cell anemia born in NYS in 2006-2009 and enrolled essentially continuously in Medicaid for the first 4 years of life. Medicaid data were used to examine hydroxyurea usage in this group by age at first prescription fill, persistence, region, treatment institution, and year. Log-binomial regression models were used to estimate the likelihood of receiving hydroxyurea treatment. Data from birth through 2014 for all members of the study group were assembled and analyzed in 2015. About 25% of the cohort had at least one filled hydroxyurea prescription by their fifth birthday, and nearly 40% by the end of the study period. The mean proportion of days covered for the first year of therapy was 56.3%. Adherence was also assessed by calculating medication possession ratios for individual treatment periods. Slightly more than one third of treated children showed 80% coverage by these measures. There was a consistent, but not statistically significant, trend toward younger age at first fill. Significant regional and treatment center differences in initiation of hydroxyurea use, but not in persistence after initiation, were noted among NYS centers. Subsequent to clinical studies demonstrating safety, current NYS-wide use of hydroxyurea in young children with sickle cell anemia appears to be widespread and increasing. However, practice differences between treatment centers and inadequate adherence may limit the full disease-modifying effects of hydroxyurea. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Hydroxyurea-Lactose Interaction Study: In Silico and In Vitro Evaluation.

PubMed

Bachchhao, Kunal B; Patil, R R; Patil, C R; Patil, Dipak D

2017-11-01

The Maillard reaction between hydroxyurea (a primary amine-containing drug) and lactose (used as an excipient) was explored. The adduct of these compounds was synthesized by heating hydroxyurea with lactose monohydrate at 60 °C in borate buffer (pH 9.2) for 12 h. Synthesis of the adduct was confirmed using UV-visible spectroscopy and Fourier transform infrared, differential scanning calorimetry, high-pressure liquid chromatography, and liquid chromatography-mass spectrometry studies. An in silico investigation of how the adduct formation affected the interactions of hydroxyurea with its biological target oxyhemoglobin, to which it binds to generate nitric oxide and regulates fetal hemoglobin synthesis, was carried out. The in silico evaluations were complemented by an in vitro assay of the anti-sickling activity. Co-incubation of hydroxyurea with deoxygenated blood samples reduced the percentage of sickled cells from 38% to 12 ± 1.6%, whereas the percentage of sickled cells in samples treated with the adduct was 17 ± 1.2%. This indicated loss of anti-sickling activity in the case of the adduct. This study confirmed that hydroxyurea can participate in a Maillard reaction if lactose is used as a diluent. Although an extended study at environmentally feasible temperatures was not carried out in the present investigation, the partial loss of the anti-sickling activity of hydroxyurea was investigated along with the in silico drug-target interactions. The results indicated that the use of lactose in hydroxyurea formulations needs urgent reconsideration and that lactose must be replaced by other diluents that do not form Maillard adducts.

Cyclical thrombocytosis, acquired von Willebrand syndrome and aggressive non-melanoma skin cancers are common in patients with Philadelphia-negative myeloproliferative neoplasms treated with hydroxyurea.

PubMed

Verner, Emma; Forsyth, Cecily; Grigg, Andrew

2014-05-01

Abstract Cyclical thrombocytosis, acquired von Willebrand syndrome, aggressive non-melanoma skin cancers and other hydroxyurea complications have been reported in Philadelphia-negative myeloproliferative neoplasms (MPNs), but their incidence and clinical consequences have not been defined in a large cohort of patients. We conducted a retrospective analysis of 188 consecutive patients with MPNs specifically addressing the incidence of these complications. Cyclical thrombocytosis was documented in 29 patients (15%), the majority of whom were receiving hydroxyurea. Acquired von Willebrand syndrome was identified in 17 of the 84 screened patients (20%), but was not associated with any major bleeding complications. Non-melanoma skin cancers were reported in 51 patients (27%). Hydroxyurea-related fever occurred in nine of 149 patients (6%) who received hydroxyurea. Seventy-three patients (39%) experienced a total of 98 major thrombotic events, with the majority of these occurring prior to or within 3 months of the diagnosis. Cyclical thrombocytosis, acquired von Willebrand syndrome, aggressive non-melanoma skin cancers and other hydroxyurea-related complications are not infrequent in MPNs and have important clinical consequences for management.

Twenty-Nail Transverse Melanonychia Induced by Hydroxyurea: Case Report and Review of the Literature.

PubMed

Osemwota, Osamuede; Uhlemann, John; Rubin, Adam

2017-08-01

Twenty-nail transverse melanonychia from hydroxyurea is a rare phenomenon, only reported four times previously. Here we describe a 51-year-old female who presented with 20-nail transverse melanonychia 3 months after initiating hydroxyurea therapy. Transverse melanonychia is a benign process but can cause patients significant distress, and thus is an entity with which dermatologists should recognize. We then review the cutaneous manifestations, differential diagnosis, and clinical considerations when evaluating patients with transverse melanonychia from hydroxyurea or other causes.

J Drugs Dermatol. 2017;16(8):814-815.

Whole exome sequencing identifies novel genes for fetal hemoglobin response to hydroxyurea in children with sickle cell anemia.

PubMed

Sheehan, Vivien A; Crosby, Jacy R; Sabo, Aniko; Mortier, Nicole A; Howard, Thad A; Muzny, Donna M; Dugan-Perez, Shannon; Aygun, Banu; Nottage, Kerri A; Boerwinkle, Eric; Gibbs, Richard A; Ware, Russell E; Flanagan, Jonathan M

2014-01-01

Hydroxyurea has proven efficacy in children and adults with sickle cell anemia (SCA), but with considerable inter-individual variability in the amount of fetal hemoglobin (HbF) produced. Sibling and twin studies indicate that some of that drug response variation is heritable. To test the hypothesis that genetic modifiers influence pharmacological induction of HbF, we investigated phenotype-genotype associations using whole exome sequencing of children with SCA treated prospectively with hydroxyurea to maximum tolerated dose (MTD). We analyzed 171 unrelated patients enrolled in two prospective clinical trials, all treated with dose escalation to MTD. We examined two MTD drug response phenotypes: HbF (final %HbF minus baseline %HbF), and final %HbF. Analyzing individual genetic variants, we identified multiple low frequency and common variants associated with HbF induction by hydroxyurea. A validation cohort of 130 pediatric sickle cell patients treated to MTD with hydroxyurea was genotyped for 13 non-synonymous variants with the strongest association with HbF response to hydroxyurea in the discovery cohort. A coding variant in Spalt-like transcription factor, or SALL2, was associated with higher final HbF in this second independent replication sample and SALL2 represents an outstanding novel candidate gene for further investigation. These findings may help focus future functional studies and provide new insights into the pharmacological HbF upregulation by hydroxyurea in patients with SCA.

Modeling and Proposed Molecular Mechanism of Hydroxyurea Through Docking and Molecular Dynamic Simulation to Curtail the Action of Ribonucleotide Reductase.

PubMed

Iman, Maryam; Khansefid, Zeynab; Davood, Asghar

2016-01-01

Ribonucleotide Reductase (RNR) is an important anticancer chemotherapy target. It has main key role in DNA synthesis and cell growth. Therefore several RNR inhibitors, such as hydroxyurea, have entered the clinical trials. Based on our proposed mechanism, radical site of RNR protein reacts with hydroxyurea in which hydroxyurea is converted into its oxidized form compound III, and whereby the tyrosyl radical is converted into a normal tyrosine residue. In this study, docking and molecular dynamics simulations were used for proposed molecular mechanism of hydroxyurea in RNR inhibition as anticancer agent. The binding affinity of hydroxyurea and compound III to RNR was studied by docking method. The docking study was performed for the crystal structure of human RNR with the radical scavenger Hydroxyurea and its oxidized form to inhibit the human RNR. hydroxyurea and compound III bind at the active site with Tyr-176, which are essential for free radical formation. This helps to understand the functional aspects and also aids in the development of novel inhibitors for the human RNR2. To confirm the binding mode of inhibitors, the molecular dynamics (MD) simulations were performed using GROMACS 4.5.5, based upon the docked conformation of inhibitors. Both of the studied compounds stayed in the active site. The results of MD simulations confirmed the binding mode of ligands, accuracy of docking and the reliability of active conformations which were obtained by AutoDock. MD studies confirm our proposed mechanism in which compound III reacts with the active site residues specially Tyr-176, and inhibits the radical generation and subsequently inhibits the RNR enzyme.

A multicenter randomised controlled trial of hydroxyurea (hydroxycarbamide) in very young children with sickle cell anaemia

PubMed Central

Wang, Winfred C; Ware, Russell E; Miller, Scott T; Iyer, Rathi V; Casella, James F; Minniti, Caterina P; Rana, Sohail; Thornburg, Courtney D; Rogers, Zora R; Kalpatthi, Ram V; Barredo, Julio C; Brown, R Clark; Sarnaik, Sharada A; Howard, Thomas H; Wynn, Lynn W; Kutlar, Abdullah; Armstrong, F Daniel; Files, Beatrice A; Goldsmith, Jonathan C; Waclawiw, Myron A; Huang, Xiangke; Thompson, Bruce W

2011-01-01

Background Sickle cell anaemia (SCA) is associated with significant morbidity from acute complications and organ dysfunction beginning in the first year of life. In the first multicenter randomised double-blinded trial in very young children with SCA, the impact of hydroxyurea (hydroxycarbamide) therapy on organ dysfunction, clinical complications, and laboratory findings, and its toxicity, were examined. Methods Eligible subjects had HbSS or Sβ0thalassaemia, were age 9–18 months at randomisation, and were not selected for clinical severity. Subjects received liquid hydroxyurea, 20 mg/kg/day, or placebo for two years. Primary study endpoints were splenic function (qualitative uptake on 99Tc spleen scan) and renal function (glomerular filtration rate by 99mTc-DTPA clearance). Additional evaluations included: blood counts, HbF, chemistry profiles, spleen function biomarkers, urine osmolality, neurodevelopment, transcranial Doppler ultrasonography, growth, and mutagenicity. Study visits occurred every two to four weeks. Findings Ninety-six subjects received hydroxyurea and 97 placebo; 86% completed the study. Significant differences were not seen for the primary endpoints, but suggestive benefit was noted in quantitative measures of spleen function. Hydroxyurea significantly decreased pain and dactylitis with trends for decreased acute chest syndrome, hospitalisation and transfusion. Hydroxyurea increased haemoglobin and HbF and decreased WBC count. Toxicity was limited to mild-moderate neutropaenia. Interpretation Although hydroxyurea treatment did not reduce splenic and renal dysfunction assessed by primary endpoint measures, it resulted in major clinical benefit because of diminished acute complications, favorable haematologic results, and a lack of unexpected toxicities. Based on the safety and efficacy data from this trial, hydroxyurea can now be considered for all very young children with SCA. PMID:21571150

HYDROXYUREA TREATMENT DECREASES GLOMERULAR HYPERFILTRATION IN CHILDREN WITH SICKLE CELL ANEMIA

PubMed Central

Aygun, Banu; Mortier, Nicole A.; Smeltzer, Matthew P.; Shulkin, Barry L.; Hankins, Jane S.; Ware, Russell E.

2015-01-01

Background Glomerular hyperfiltration and microalbuminuria/proteinuria are early manifestations of sickle nephropathy. The effects of hydroxyurea therapy on these renal manifestations of sickle cell anemia (SCA) are not well defined. Objective To investigate the effects of hydroxyurea on glomerular filtration rate (GFR) measured by 99mTc-DTPA clearance, and on microalbuminuria/proteinuria in children with SCA. Study Design Hydroxyurea Study of Long-Term Effects (HUSTLE) is a prospective study (NCT00305175) with the goal of describing the long-term cellular, molecular, and clinical effects of hydroxyurea therapy in SCA. Glomerular filtration rate, urine microalbumin, and serum cystatin C were measured before initiating hydroxyurea therapy and then repeated after 3 years. Baseline and Year 3 values for HUSTLE subjects were compared using the Wilcoxon Signed Rank test. Associations between continuous variables were evaluated using Spearman correlation coefficient. Results Twenty-three children with SCA (median age 7.5 years, range 2.5–14.0 years) received hydroxyurea at maximum tolerated dose (MTD, 24.4 ± 4.5 mg/kg/day, range 15.3–30.6 mg/kg/day). After three years of treatment, GFR measured by 99mTc-DTPA decreased significantly from 167 ± 46 mL/min/1.73m2 to 145 ± 27 mL/min/1.73m2 (p=0.016). This decrease in GFR was significantly associated with increase in fetal hemoglobin (p= 0.042) and decrease in lactate dehydrogenase levels (p=0.035). Urine microalbumin and cystatin C levels did not change significantly. Conclusions Hydroxyurea at MTD is associated with a decrease in hyperfiltration in young children with SCA. PMID:23255310

The effect of hydroxyurea on compound heterozygotes for sickle cell-hemoglobin D-Punjab--a single centre experience in eastern India.

PubMed

Patel, Siris; Purohit, Prasanta; Mashon, Ranjeet Singh; Dehury, Snehadhini; Meher, Satyabrata; Sahoo, Sulia; Dash, Subhransu Sekhar; Das, Kishalaya; Das, Padmalaya; Patel, Dilip Kumar

2014-08-01

Although hydroxyurea is the only effective agent for the treatment of sickle cell disease, published experience with this drug is limited to treatment of homozygous sickle cell anemia and HbS/β thalassemia. The role of hydroxyurea in the treatment of patients with HbSD-Punjab, a rare hemoglobinopathy with phenotypic expression similar to that of sickle cell anemia is unknown. Over a period of 10 years, we followed 42 patients with HbSD-Punjab, of which 20 presented with severe clinical manifestations (≥3 episodes of VOC and/or ≥2 units of blood transfusion in the previous 12 months). These 20 patients were enrolled for treatment with hydroxyurea at a dose of 10 mg/kg/day and followed prospectively for a period of 24 months. The frequency of VOC decreased significantly and none of them required blood transfusion while receiving hydroxyurea. The HbF, total hemoglobin, MCV, MCH, and MCHC levels increased significantly, whereas HbS, WBC, platelet count, total serum bilirubin, and LDH levels decreased significantly in all the patients. No short-term drug toxicity was observed. This study describes the use of hydroxyurea therapy in patients with HbSD-Punjab. Low dose hydroxyurea (10 mg/kg/day) was found to be effective in reducing the clinical severity in patients with HbSD-Punjab without any short-term toxicity. In view of easy affordability amongst poor patients, widespread acceptability by patients and doctors, the need of infrequent monitoring and its potential effectiveness, low dose hydroxyurea is suitable for treatment of patients with HbSD-Punjab. © 2014 Wiley Periodicals, Inc.

Hydroxyurea Therapy for Children With Sickle Cell Anemia in Sub‐Saharan Africa: Rationale and Design of the REACH Trial

PubMed Central

Tshilolo, Léon; Santos, Brigida; Tomlinson, George A.; Stuber, Susan; Latham, Teresa; Aygun, Banu; Obaro, Stephen K.; Olupot‐Olupot, Peter; Williams, Thomas N.; Odame, Isaac; Ware, Russell E.

2015-01-01

Background Sickle cell anemia (SCA) is an inherited hematological disorder that causes a large but neglected global health burden, particularly in Africa. Hydroxyurea represents the only available disease‐modifying therapy for SCA, and has proven safety and efficacy in high‐resource countries. In sub‐Saharan Africa, there is minimal use of hydroxyurea, due to lack of data, absence of evidence‐based guidelines, and inexperience among healthcare providers. Procedure A partnership was established between investigators in North America and sub‐Saharan Africa, to develop a prospective multicenter research protocol designed to provide data on the safety, feasibility, and benefits of hydroxyurea for children with SCA. Results The Realizing Effectiveness Across Continents with Hydroxyurea (REACH, ClinicalTrials.gov NCT01966731) trial is a prospective, phase I/II open‐label dose escalation study of hydroxyurea that will treat a total of 600 children age 1–10 years with SCA: 150 at each of four different clinical sites within sub‐Saharan Africa (Angola, Democratic Republic of Congo, Kenya, and Uganda). The primary study endpoint will be severe hematological toxicities that occur during the fixed‐dose treatment phase. REACH has an adaptive statistical design that allows for careful assessment of toxicities to accurately identify a safe hydroxyurea dose. Conclusions REACH will provide data that address critical gaps in knowledge for the treatment of SCA in sub‐Saharan Africa. By developing local expertise with the use of hydroxyurea and helping to establish treatment guidelines, the REACH trial results will have the potential to transform care for children with SCA in Africa. Pediatr Blood Cancer © 2015 Wiley Periodicals, Inc. PMID:26275071

Hydroxyurea Therapy for Children With Sickle Cell Anemia in Sub-Saharan Africa: Rationale and Design of the REACH Trial.

PubMed

McGann, Patrick T; Tshilolo, Léon; Santos, Brigida; Tomlinson, George A; Stuber, Susan; Latham, Teresa; Aygun, Banu; Obaro, Stephen K; Olupot-Olupot, Peter; Williams, Thomas N; Odame, Isaac; Ware, Russell E

2016-01-01

Sickle cell anemia (SCA) is an inherited hematological disorder that causes a large but neglected global health burden, particularly in Africa. Hydroxyurea represents the only available disease-modifying therapy for SCA, and has proven safety and efficacy in high-resource countries. In sub-Saharan Africa, there is minimal use of hydroxyurea, due to lack of data, absence of evidence-based guidelines, and inexperience among healthcare providers. A partnership was established between investigators in North America and sub-Saharan Africa, to develop a prospective multicenter research protocol designed to provide data on the safety, feasibility, and benefits of hydroxyurea for children with SCA. The Realizing Effectiveness Across Continents with Hydroxyurea (REACH, ClinicalTrials.gov NCT01966731) trial is a prospective, phase I/II open-label dose escalation study of hydroxyurea that will treat a total of 600 children age 1-10 years with SCA: 150 at each of four different clinical sites within sub-Saharan Africa (Angola, Democratic Republic of Congo, Kenya, and Uganda). The primary study endpoint will be severe hematological toxicities that occur during the fixed-dose treatment phase. REACH has an adaptive statistical design that allows for careful assessment of toxicities to accurately identify a safe hydroxyurea dose. REACH will provide data that address critical gaps in knowledge for the treatment of SCA in sub-Saharan Africa. By developing local expertise with the use of hydroxyurea and helping to establish treatment guidelines, the REACH trial results will have the potential to transform care for children with SCA in Africa. © 2015 The Authors. Pediatric Blood & Cancer Published by Wiley Periodicals, Inc.

Editor's Highlight: Hydroxyurea Exposure Activates the P53 Signaling Pathway in Murine Organogenesis-Stage Embryos

PubMed Central

El Husseini, Nazem; Schlisser, Ava E.; Hales, Barbara F.

2016-01-01

Hydroxyurea, an anticancer agent and potent teratogen, induces oxidative stress and activates a DNA damage response pathway in the gestation day (GD) 9 mouse embryo. To delineate the stress response pathways activated by this drug, we investigated the effect of hydroxyurea exposure on the transcriptome of GD 9 embryos. Timed pregnant CD-1 mice were treated with saline or hydroxyurea (400 mg/kg or 600 mg/kg) on GD 9; embryonic gene and protein expression were examined 3 h later. Microarray analysis revealed that the expression of 1346 probe sets changed significantly in embryos exposed to hydroxyurea compared with controls; the P53 signaling pathway was highly affected. In addition, P53 related family members, P63 and P73, were predicted to be activated and had common and unique downstream targets. Western blot analysis revealed that active phospho-P53 was significantly increased in drug-exposed embryos; confocal microscopy showed that the translocation of phospho-P53 to the nucleus was widespread in the embryo. Furthermore, qRT-PCR showed that the expression of P53-regulated genes (Cdkn1A, Fas, and Trp53inp1) was significantly upregulated in hydroxyurea-exposed embryos; the concentration of the redox sensitive P53INP1 protein was also increased in a hydroxyurea dose-dependent fashion. Thus, hydroxyurea elicits a significant effect on the transcriptome of the organogenesis stage murine embryo, activating several key developmental signaling pathways related to DNA damage and oxidative stress. We propose that the P53 pathway plays a central role in the embryonic stress response and the developmental outcome after teratogen exposure. PMID:27208086

Hydroxyurea therapy requires HbF induction for clinical benefit in a sickle cell mouse model

PubMed Central

Lebensburger, Jeffrey D.; Pestina, Tamara I.; Ware, Russell E.; Boyd, Kelli L.; Persons, Derek A.

2010-01-01

Hydroxyurea has proven clinical efficacy in patients with sickle cell disease. Potential mechanisms for the beneficial effects include fetal hemoglobin induction and the reduction of cell adhesive properties, inflammation and hypercoagulability. Using a murine model of sickle cell disease in which fetal hemoglobin induction does not occur, we evaluated whether hydroxyurea administration would still yield improvements in hematologic parameters and reduce end-organ damage. Animals given a maximally tolerated dose of hydroxyurea that resulted in significant reductions in the neutrophil and platelet counts showed no improvement in hemolytic anemia and end-organ damage compared to control mice. In contrast, animals having high levels of fetal hemoglobin due to gene transfer with a γ-globin lentiviral vector showed correction of anemia and organ damage. These data suggest that induction of fetal hemoglobin by hydroxyurea is an essential mechanism for its clinical benefits. PMID:20378564

Hydroxyurea therapy contributes to infertility in adult men with sickle cell disease: a review.

PubMed

DeBaun, Michael R

2014-12-01

Hydroxyurea therapy, a chemotherapeutic agent, is the only US FDA approved therapy for the prevention of vaso-occlusive pain in sickle cell disease (SCD). The National Institutes of Health has sponsored two Phase III randomized, placebo-controlled trials, initially in adults, and subsequently in children with sickle cell anemia (SCA). Despite the overwhelming evidence that hydroxyurea therapy is beneficial to children and adults with SCA, individuals with SCA and their families express reservations about its use, in part because of the concerns about fertility, particularly in men. As adolescent boys with SCD are now expected to reach their reproductive years, a new concern is emerging about the role of hydroxyurea therapy as a barrier to their progeny. This review will systemically evaluate compromised fertility in men with SCD, and the evidence that hydroxyurea therapy is associated with further decreasing fertility in men with SCD.

Survival and mortality among users and non-users of hydroxyurea with sickle cell disease

PubMed Central

de Araujo, Olinda Maria Rodrigues; Ivo, Maria Lúcia; Ferreira, Marcos Antonio; Pontes, Elenir Rose Jardim Cury; Bispo, Ieda Maria Gonçalves Pacce; de Oliveira, Eveny Cristine Luna

2015-01-01

OBJECTIVE: to estimate survival, mortality and cause of death among users or not of hydroxyurea with sickle cell disease. METHOD: cohort study with retrospective data collection, from 1980 to 2010 of patients receiving inpatient treatment in two Brazilian public hospitals. The survival probability was determined using the Kaplan-Meier estimator, survival calculations (SPSS version 10.0), comparison between survival curves, using the log rank method. The level of significance was p=0.05. RESULTS: of 63 patients, 87% had sickle cell anemia, with 39 using hydroxyurea, with a mean time of use of the drug of 20.0±10.0 years and a mean dose of 17.37±5.4 to 20.94±7.2 mg/kg/day, raising the fetal hemoglobin. In the comparison between those using hydroxyurea and those not, the survival curve was greater among the users (p=0.014). A total of 10 deaths occurred, with a mean age of 28.1 years old, and with Acute Respiratory Failure as the main cause. CONCLUSION: the survival curve is greater among the users of hydroxyurea. The results indicate the importance of the nurse incorporating therapeutic advances of hydroxyurea in her care actions. PMID:25806633

Hydroxyurea could be a good clinically relevant iron chelator.

PubMed

Italia, Khushnooma; Colah, Roshan; Ghosh, Kanjaksha

2013-01-01

Our previous study showed a reduction in serum ferritin of β-thalassemia patients on hydroxyurea therapy. Here we aimed to evaluate the efficacy of hydroxyurea alone and in combination with most widely used iron chelators like deferiprone and deferasirox for reducing iron from experimentally iron overloaded mice. 70 BALB/c mice received intraperitonial injections of iron-sucrose. The mice were then divided into 8 groups and were orally given hydroxyurea, deferiprone or deferasirox alone and their combinations for 4 months. CBC, serum-ferritin, TBARS, sTfr and hepcidin were evaluated before and after iron overload and subsequently after 4 months of drug therapy. All animals were then killed. Iron staining of the heart and liver tissue was done using Perl's Prussian Blue stain. Dry weight of iron in the heart and liver was determined by atomic absorption spectrometry. Increased serum-ferritin, TBARS, hepcidin and dry weight of iron in the liver and heart showed a significant reduction in groups treated with iron chelators with maximum reduction in the group treated with a combination of deferiprone, deferasirox and hydroxyurea. Thus hydroxyurea proves its role in reducing iron from iron overloaded mice. The iron chelating effect of these drugs can also be increased if given in combination.

Survival and mortality among users and non-users of hydroxyurea with sickle cell disease.

PubMed

de Araujo, Olinda Maria Rodrigues; Ivo, Maria Lúcia; Ferreira Júnior, Marcos Antonio; Pontes, Elenir Rose Jardim Cury; Bispo, Ieda Maria Gonçalves Pacce; de Oliveira, Eveny Cristine Luna

2015-01-01

to estimate survival, mortality and cause of death among users or not of hydroxyurea with sickle cell disease. cohort study with retrospective data collection, from 1980 to 2010 of patients receiving inpatient treatment in two Brazilian public hospitals. The survival probability was determined using the Kaplan-Meier estimator, survival calculations (SPSS version 10.0), comparison between survival curves, using the log rank method. The level of significance was p=0.05. of 63 patients, 87% had sickle cell anemia, with 39 using hydroxyurea, with a mean time of use of the drug of 20.0±10.0 years and a mean dose of 17.37±5.4 to 20.94±7.2 mg/kg/day, raising the fetal hemoglobin. In the comparison between those using hydroxyurea and those not, the survival curve was greater among the users (p=0.014). A total of 10 deaths occurred, with a mean age of 28.1 years old, and with Acute Respiratory Failure as the main cause. the survival curve is greater among the users of hydroxyurea. The results indicate the importance of the nurse incorporating therapeutic advances of hydroxyurea in her care actions.

Whole Exome Sequencing Identifies Novel Genes for Fetal Hemoglobin Response to Hydroxyurea in Children with Sickle Cell Anemia

PubMed Central

Sheehan, Vivien A.; Crosby, Jacy R.; Sabo, Aniko; Mortier, Nicole A.; Howard, Thad A.; Muzny, Donna M.; Dugan-Perez, Shannon; Aygun, Banu; Nottage, Kerri A.; Boerwinkle, Eric; Gibbs, Richard A.; Ware, Russell E.; Flanagan, Jonathan M.

2014-01-01

Hydroxyurea has proven efficacy in children and adults with sickle cell anemia (SCA), but with considerable inter-individual variability in the amount of fetal hemoglobin (HbF) produced. Sibling and twin studies indicate that some of that drug response variation is heritable. To test the hypothesis that genetic modifiers influence pharmacological induction of HbF, we investigated phenotype-genotype associations using whole exome sequencing of children with SCA treated prospectively with hydroxyurea to maximum tolerated dose (MTD). We analyzed 171 unrelated patients enrolled in two prospective clinical trials, all treated with dose escalation to MTD. We examined two MTD drug response phenotypes: HbF (final %HbF minus baseline %HbF), and final %HbF. Analyzing individual genetic variants, we identified multiple low frequency and common variants associated with HbF induction by hydroxyurea. A validation cohort of 130 pediatric sickle cell patients treated to MTD with hydroxyurea was genotyped for 13 non-synonymous variants with the strongest association with HbF response to hydroxyurea in the discovery cohort. A coding variant in Spalt-like transcription factor, or SALL2, was associated with higher final HbF in this second independent replication sample and SALL2 represents an outstanding novel candidate gene for further investigation. These findings may help focus future functional studies and provide new insights into the pharmacological HbF upregulation by hydroxyurea in patients with SCA. PMID:25360671

Evidence review of hydroxyurea for the prevention of sickle cell complications in low-income countries.

PubMed

Mulaku, Mercy; Opiyo, Newton; Karumbi, Jamlick; Kitonyi, Grace; Thoithi, Grace; English, Mike

2013-11-01

Hydroxyurea is widely used in high-income countries for the management of sickle cell disease (SCD) in children. In Kenyan clinical guidelines, hydroxyurea is only recommended for adults with SCD. Yet many deaths from SCD occur in early childhood, deaths that might be prevented by an effective, disease modifying intervention. The aim of this review was to summarise the available evidence on the efficacy, effectiveness and safety of hydroxyurea in the management of SCD in children below 5 years of age to support guideline development in Kenya. We undertook a systematic review and used the Grading of Recommendations Assessment, Development and Evaluation system to appraise the quality of identified evidence. Overall, available evidence from 1 systematic review (n=26 studies), 2 randomised controlled trials (n=354 children), 14 observational studies and 2 National Institute of Health reports suggest that hydroxyurea may be associated with improved fetal haemoglobin levels, reduced rates of hospitalisation, reduced episodes of acute chest syndrome and decreased frequency of pain events in children with SCD. However, it is associated with adverse events (eg, neutropenia) when high to maximum tolerated doses are used. Evidence is lacking on whether hydroxyurea improves survival if given to young children. Majority of the included studies were of low quality and mainly from high-income countries. Overall, available limited evidence suggests that hydroxyurea may improve morbidity and haematological outcomes in SCD in children aged below 5 years and appears safe in settings able to provide consistent haematological monitoring.

Hydroxyurea-Increased Fetal Hemoglobin Is Associated with Less Organ Damage and Longer Survival in Adults with Sickle Cell Anemia.

PubMed

Fitzhugh, Courtney D; Hsieh, Matthew M; Allen, Darlene; Coles, Wynona A; Seamon, Cassie; Ring, Michael; Zhao, Xiongce; Minniti, Caterina P; Rodgers, Griffin P; Schechter, Alan N; Tisdale, John F; Taylor, James G

2015-01-01

Adults with sickle cell anemia (HbSS) are inconsistently treated with hydroxyurea. We retrospectively evaluated the effects of elevating fetal hemoglobin with hydroxyurea on organ damage and survival in patients enrolled in our screening study between 2001 and 2010. An electronic medical record facilitated development of a database for comparison of study parameters based on hydroxyurea exposure and dose. This study is registered with ClinicalTrials.gov, number NCT00011648. Three hundred eighty-three adults with homozygous sickle cell disease were analyzed with 59 deaths during study follow-up. Cox regression analysis revealed deceased subjects had more hepatic dysfunction (elevated alkaline phosphatase, Hazard Ratio = 1.005, 95% CI 1.003-1.006, p<0.0.0001), kidney dysfunction (elevated creatinine, Hazard Ratio = 1.13, 95% CI 1.00-1.27, p = 0.043), and cardiopulmonary dysfunction (elevated tricuspid jet velocity on echocardiogram, Hazard Ratio = 2.22, 1.23-4.02, p = 0.0082). Sixty-six percent of subjects were treated with hydroxyurea, although only 66% of those received a dose within the recommended therapeutic range. Hydroxyurea use was associated with improved survival (Hazard Ratio = 0.58, 95% CI 0.34-0.97, p = 0.040). This effect was most pronounced in those taking the recommended dose of 15-35 mg/kg/day (Hazard Ratio 0.36, 95% CI 0.17-0.73, p = 0.0050). Hydroxyurea use was not associated with changes in organ function over time. Further, subjects with higher fetal hemoglobin responses to hydroxyurea were more likely to survive (p = 0.0004). While alkaline phosphatase was lowest in patients with the best fetal hemoglobin response (95.4 versus 123.6, p = 0.0065 and 96.1 versus 113.6U/L, p = 0.041 at first and last visits, respectively), other markers of organ damage were not consistently improved over time in patients with the highest fetal hemoglobin levels. Our data suggest that adults should be treated with the maximum tolerated hydroxyurea dose, ideally before organ damage occurs. Prospective studies are indicated to validate these findings.

Hydroxyurea-Increased Fetal Hemoglobin Is Associated with Less Organ Damage and Longer Survival in Adults with Sickle Cell Anemia

PubMed Central

Fitzhugh, Courtney D.; Hsieh, Matthew M.; Allen, Darlene; Coles, Wynona A.; Seamon, Cassie; Ring, Michael; Zhao, Xiongce; Minniti, Caterina P.; Rodgers, Griffin P.; Schechter, Alan N.; Tisdale, John F.; Taylor, James G.

2015-01-01

Background Adults with sickle cell anemia (HbSS) are inconsistently treated with hydroxyurea. Objectives We retrospectively evaluated the effects of elevating fetal hemoglobin with hydroxyurea on organ damage and survival in patients enrolled in our screening study between 2001 and 2010. Methods An electronic medical record facilitated development of a database for comparison of study parameters based on hydroxyurea exposure and dose. This study is registered with ClinicalTrials.gov, number NCT00011648. Results Three hundred eighty-three adults with homozygous sickle cell disease were analyzed with 59 deaths during study follow-up. Cox regression analysis revealed deceased subjects had more hepatic dysfunction (elevated alkaline phosphatase, Hazard Ratio = 1.005, 95% CI 1.003–1.006, p<0.0.0001), kidney dysfunction (elevated creatinine, Hazard Ratio = 1.13, 95% CI 1.00–1.27, p = 0.043), and cardiopulmonary dysfunction (elevated tricuspid jet velocity on echocardiogram, Hazard Ratio = 2.22, 1.23–4.02, p = 0.0082). Sixty-six percent of subjects were treated with hydroxyurea, although only 66% of those received a dose within the recommended therapeutic range. Hydroxyurea use was associated with improved survival (Hazard Ratio = 0.58, 95% CI 0.34–0.97, p = 0.040). This effect was most pronounced in those taking the recommended dose of 15–35 mg/kg/day (Hazard Ratio 0.36, 95% CI 0.17–0.73, p = 0.0050). Hydroxyurea use was not associated with changes in organ function over time. Further, subjects with higher fetal hemoglobin responses to hydroxyurea were more likely to survive (p = 0.0004). While alkaline phosphatase was lowest in patients with the best fetal hemoglobin response (95.4 versus 123.6, p = 0.0065 and 96.1 versus 113.6U/L, p = 0.041 at first and last visits, respectively), other markers of organ damage were not consistently improved over time in patients with the highest fetal hemoglobin levels. Conclusions Our data suggest that adults should be treated with the maximum tolerated hydroxyurea dose, ideally before organ damage occurs. Prospective studies are indicated to validate these findings. PMID:26576059

Cutaneous ulcers associated with hydroxyurea therapy.

PubMed

Quattrone, Filippo; Dini, Valentina; Barbanera, Sabrina; Zerbinati, Nicola; Romanelli, Marco

2013-11-01

Hydroxyurea is an antitumoral drug mainly used in the treatment of Philadelphia chromosome-negative myeloproliferative syndromes and sickle-cell disease. Ulcers represent a rare but severe long-term adverse effect of hydroxyurea therapy. Hydroxyurea-induced ulcers are often multiple and bilateral, typically developing in the perimalleolar region, although any cutaneous district is potentially affected. They generally look small, well-defined, shallow with an adherent, yellow, fibrinous necrotic base. A constant finding is also an extremely intense, treatment-resistant pain accompanying these ulcerations. Withdrawal of the drug generally leads to spontaneous healing of these lesions. Care providers tend to show insufficient awareness of this highly debilitating cutaneous side effect, and late or missed diagnoses are frequent. Instead, regular dermatologic screening should be performed on hydroxyurea-treated patients. This article will present a comprehensive review of indexed case reports and clinical studies, followed by a discussion about treatment options aiming at increasing knowledge about this specific topic. Copyright © 2013 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

Maintaining Genome Stability: The Role of Helicases and Deaminases

DTIC Science & Technology

2006-07-01

functional for replication. Then, we screened the surviving transformants for sensitivity to hydroxyurea . Our first screen was conducted under conditions...that are lethal for checkpoint mutants such as ∆rad3. We did not observe any hydroxyurea -sensitive MCM clones. However, following the old genetics...this kinase. In particular, we observe that an mcm4ts mutant blocked in hydroxyurea , and then released to restrictive temperature, is competent to

Maintaining Genome Stability: The Role of Helicases and Deaminases

DTIC Science & Technology

2007-07-01

transformants for sensitivity to hydroxyurea . Our first screen was conducted under conditions that are lethal for checkpoint mutants such as ∆rad3...We did not observe any hydroxyurea -sensitive MCM clones. However, following the old genetics adage “absence of evidence is not evidence of... hydroxyurea , and then released to restrictive temperature, is competent to complete replication and go on to divide. In contrast, this mutant shifted

The influence of hydroxyurea on oxidative stress in sickle cell anemia

PubMed Central

Torres, Lidiane de Souza; da Silva, Danilo Grünig Humberto; Belini Junior, Edis; de Almeida, Eduardo Alves; Lobo, Clarisse Lopes de Castro; Cançado, Rodolfo Delfini; Ruiz, Milton Artur; Bonini-Domingos, Claudia Regina

2012-01-01

Objective The oxidative stress in 20 sickle cell anemia patients taking hydroxyurea and 13 sickle cell anemia patients who did not take hydroxyurea was compared with a control group of 96 individuals without any hemoglobinopathy. Methods Oxidative stress was assessed by thiobarbituric acid reactive species production, the Trolox-equivalent antioxidant capacity and plasma glutathione levels. Results Thiobarbituric acid reactive species values were higher in patients without specific medication, followed by patients taking hydroxyurea and the Control Group (p < 0.0001). The antioxidant capacity was higher in patients taking hydroxyurea and lower in the Control Group (p = 0.0002 for Trolox-equivalent antioxidant capacity and p < 0.0292 for plasma glutathione). Thiobarbituric acid reactive species levels were correlated with higher hemoglobin S levels (r = 0.55; p = 0.0040) and lower hemoglobin F concentrations(r = -0.52; p = 0.0067). On the other hand, plasma glutathione levels were negatively correlated with hemoglobin S levels (r = -0.49; p = 0.0111) and positively associated with hemoglobin F values (r = 0.56; p = 0.0031). Conclusion Sickle cell anemia patients have high oxidative stress and, conversely, increased antioxidant activity. The increase in hemoglobin F levels provided by hydroxyurea and its antioxidant action may explain the reduction in lipid peroxidation and increased antioxidant defenses in these individuals. PMID:23323065

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liebelt, E.L.; Balk, S.J.; Faber, W.

The National Toxicology Program (NTP) and the National Institute of Environmental Health Sciences (NIEHS) established the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR) in June 1998. The purpose of CERHR is to provide timely, unbiased, scientifically sound evaluations of human and experimental evidence for adverse effects on reproduction and development caused by agents to which humans may be exposed. Hydroxyurea was selected for evaluation by a CERHR expert panel because of (1) its increasing use in the treatment of sickle cell disease in children and adults, (2) knowledge that it inhibits DNA synthesis and is cytotoxic,more » and (3) published evidence of its reproductive and developmental toxicity in rodents. Hydroxyurea is FDA-approved for reducing the frequency of painful crises and the need for blood transfusions in adults with sickle cell anemia who experience recurrent moderate-to-severe crises. Hydroxyurea is used in the treatment of cancer, sickle cell disease, and thalassemia. It is the only treatment for sickle cell disease aside from blood transfusion used in children. Hydroxyurea may be used in the treatment of children and adults with sickle cell disease for an extended period of time or for repeated cycles of therapy. Treatment with hydroxyurea may be associated with cytotoxic and myelosuppressive effects, and hydroxyurea is mutagenic.« less

Patients with sickle cell disease taking hydroxyurea in the Hemocentro Regional de Montes Claros

PubMed Central

Santos, Fernanda Kelle de Souza; Maia, Caroline Nogueira

2011-01-01

Background The development of therapies for sickle cell disease has received special attention, particularly those that reduce the polymerization of hemoglobin S. Hydroxyurea is a commonly used medication because it has the ability to raise levels of fetal hemoglobin, decrease the frequency of vaso-occlusive episodes and thus improve the clinical course of sickle cell disease patients. Objective To study hematological data and the clinical profile of sickle cell disease patients taking hydroxyurea in a regional blood center. Methods From the charts of 20 patients with sickle cell anemia, the clinical outcomes and a number of hematological variables were analyzed before and during treatment with hydroxyurea. Results The patients' ages ranged from 6 to 41 years old, most were dark skinned and there was a predominance of women. The main symptom that defined whether patients were prescribed hydroxyurea was painful crises followed by hospitalizations. During treatment with hydroxyurea there were significant increases in hemoglobin, fetal hemoglobin, mean corpuscular volume and mean corpuscular hemoglobin. The reticulocyte and white blood cell counts dropped significantly with treatment. A positive correlation was found between fetal hemoglobin and mean corpuscular volume before and during treatment. Additionally, a correlation was found between the white blood cell and reticulocyte counts before treatment with hydroxyurea. Conclusion Most patients showed improvements with treatment as demonstrated by increases in hemoglobin, fetal hemoglobin and mean corpuscular volume, as well as by reductions in the reticulocyte and white blood cell counts. Clinically, more than 50% of patients had a significant reduction of events. PMID:23284256

Editor's Highlight: Hydroxyurea Exposure Activates the P53 Signaling Pathway in Murine Organogenesis-Stage Embryos.

PubMed

El Husseini, Nazem; Schlisser, Ava E; Hales, Barbara F

2016-08-01

Hydroxyurea, an anticancer agent and potent teratogen, induces oxidative stress and activates a DNA damage response pathway in the gestation day (GD) 9 mouse embryo. To delineate the stress response pathways activated by this drug, we investigated the effect of hydroxyurea exposure on the transcriptome of GD 9 embryos. Timed pregnant CD-1 mice were treated with saline or hydroxyurea (400 mg/kg or 600 mg/kg) on GD 9; embryonic gene and protein expression were examined 3 h later. Microarray analysis revealed that the expression of 1346 probe sets changed significantly in embryos exposed to hydroxyurea compared with controls; the P53 signaling pathway was highly affected. In addition, P53 related family members, P63 and P73, were predicted to be activated and had common and unique downstream targets. Western blot analysis revealed that active phospho-P53 was significantly increased in drug-exposed embryos; confocal microscopy showed that the translocation of phospho-P53 to the nucleus was widespread in the embryo. Furthermore, qRT-PCR showed that the expression of P53-regulated genes (Cdkn1A, Fas, and Trp53inp1) was significantly upregulated in hydroxyurea-exposed embryos; the concentration of the redox sensitive P53INP1 protein was also increased in a hydroxyurea dose-dependent fashion. Thus, hydroxyurea elicits a significant effect on the transcriptome of the organogenesis stage murine embryo, activating several key developmental signaling pathways related to DNA damage and oxidative stress. We propose that the P53 pathway plays a central role in the embryonic stress response and the developmental outcome after teratogen exposure. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Implementation of the Southwestern Oncology Group Committee on Women’s Health Research Agenda: A Special Sabbatical for the Chairperson.

DTIC Science & Technology

1996-07-01

phase II study 1987-1989 Principal Investigator, Loyola/Hines pilot study of cisplatin preceded by concurrent cytarabine and oral hydroxyurea in...Investigator, Loyola/Hines pilot study of cisplatin preceded by concurrent 31 5 intravenous hydroxyurea and cytarabine . 1989-1992 Primary Study Coordinator...Conference: Modulation of cisplatin resistance by cytarabine and hydroxyurea. Illinois Cancer Council Annual Symposium: Review of Breast Cancer Growth

Role of cdc25 Phosphatases in Human Breast Cancer

DTIC Science & Technology

2007-05-01

cellular response to 5-fluorouracil or hydroxyurea . MCF-10A cells were infected with the indicated adenoviruses for 24 hr and then treated with...doxorubicin, 5-fluorouracil, or hydroxyurea for 48 hr. Cells were stained with propidium iodide prior to flow-cytometry analyses. In order to investigate...of two chemotherapeutic agents, 5- fluorouracil (5-FU, 50 μM), an inhibitor of pyrimidine synthesis, or hydroxyurea (HU, 2mM), an inhibitor of both

Centrosome Amplification: A Potential Marker of Breast Cancer Agressiveness

DTIC Science & Technology

2006-07-01

centrosome amplification. Introduction of DNA damage in the MCF-7 cell line by treatment with hydroxyurea (HU) or daunorubicin (DR) resulted in the...cycles of DNA synthesis and mitotic division in hydroxyurea - arrested Chinese hamster ovary cells. J Cell Biol, 130: 105-115, 1995. 23. D’Assoro, A. B...from cycles of DNA synthesis and mitotic division in hydroxyurea -arrested Chinese hamster ovary cells. J Cell Biol, 1995. 130(1): p. 105-15. 22

The burden and quality of life of caregivers of sickle cell anemia patients taking hydroxyurea versus those not taking hydroxyurea

PubMed Central

da Silva, Luiz Bernardino Lima; Ivo, Maria Lúcia; de Souza, Albert Schiaveto; Pontes, Elenir Rose Jardim Cury; Pinto, Alexandra Maria Almeida Carvalho; de Araujo, Olinda Maria Rodrigues

2012-01-01

Objective To assess the burden and quality of life of caregivers of patients with sickle cell anemia taking hydroxyurea versus those of patients not taking hydroxyurea. Methods A cross-sectional study was performed of caregivers of outpatients with sickle cell anemia in two public hospitals in Campo Grande, MS, from January through June 2010. The World Health Organization Quality of Life-BREF Scale and the Caregiver Burden Scale were used. Results Of the 37 caregivers in this study, 81.1% were women, 73.0% were mothers, 59.5% were married, 54.1%were mulattos, 48.6% were housewives, 54.1% had family incomes of up to one minimum wage and 75.7% had onlycompleted elementary education. The mean duration of care provided (time after diagnosis) was 16.08 ± 9.88 yearsand 89.2% reported that they provided 24-hour care. Regarding health, 27.0% of study participants reported having physical and 13.5% emotional problems. There were no significant relationships between these variables either with the different domains or the total score of the WHOQOL-BREF comparing caregivers of patients taking hydroxyurea versusthose of patients not taking hydroxyurea. There was a moderate negative linear correlation between the WHOQOL-BREF and the Caregiver Burden Scale scores (linear correlation test of Pearson: p-value = 0.003, r = -0.477). The burden of caregivers of patients who did not take hydroxyurea was significantly higher than those of patients who took the medication in terms of general tension, disappointment, environment and total score (student t-test: p-value < 0.05). Conclusion In the perception of the caregiver, looking after sickle cell anemia patients represents a moderate negative burden. PMID:23049439

Development of a pharmacokinetic-guided dose individualization strategy for hydroxyurea treatment in children with sickle cell anaemia.

PubMed

Dong, Min; McGann, Patrick T; Mizuno, Tomoyuki; Ware, Russell E; Vinks, Alexander A

2016-04-01

Hydroxyurea has emerged as the primary disease-modifying therapy for patients with sickle cell anaemia (SCA). The laboratory and clinical benefits of hydroxyurea are optimal at maximum tolerated dose (MTD), but the current empirical dose escalation process often takes up to 12 months. The purpose of this study was to develop a pharmacokinetic-guided dosing strategy to reduce the time required to reach hydroxyurea MTD in children with SCA. Pharmacokinetic (PK) data from the HUSTLE trial (NCT00305175) were used to develop a population PK model using non-linear mixed effects modelling (nonmem 7.2). A D-optimal sampling strategy was developed to estimate individual PK and hydroxyurea exposure (area under the concentration-time curve (AUC)). The initial AUC target was derived from HUSTLE clinical data and defined as the mean AUC at MTD. PK profiles were best described by a one compartment with Michaelis-Menten elimination and a transit absorption model. Body weight and cystatin C were identified as significant predictors of hydroxyurea clearance. The following clinically feasible sampling times are included in a new prospective protocol: pre-dose (baseline), 15-20 min, 50-60 min and 3 h after an initial 20 mg kg(-1) oral dose. The mean target AUC(0,∞) for initial dose titration was 115 mg l(-1)  h. We developed a PK model-based individualized dosing strategy for the prospective Therapeutic Response Evaluation and Adherence Trial (TREAT, ClinicalTrials.gov NCT02286154). This approach has the potential to optimize the dose titration of hydroxyurea therapy for children with SCA, such that the clinical benefits at MTD are achieved more quickly. © 2015 The British Pharmacological Society.

PREVENTION OF CONVERSION TO ABNORMAL TCD WITH HYDROXYUREA IN SICKLE CELL ANEMIA: A PHASE III INTERNATIONAL RANDOMIZED CLINICAL TRIAL

PubMed Central

Hankins, Jane S.; McCarville, M. Beth; Rankine-Mullings, Angela; Reid, Marvin E.; Lobo, Clarisse L.C.; Moura, Patricia G.; Ali, Susanna; Soares, Deanne; Aldred, Karen; Jay, Dennis W.; Aygun, Banu; Bennett, John; Kang, Guolian; Goldsmith, Jonathan C.; Smeltzer, Matthew P.; Boyett, James M.; Ware, Russell E.

2015-01-01

Children with sickle cell anemia (SCA) and conditional transcranial Doppler (TCD) ultrasound velocities (170-199 cm/sec) may develop stroke. However, with limited available clinical data, the current standard of care for conditional TCD velocities is observation. The efficacy of hydroxyurea in preventing conversion from conditional to abnormal TCD (≥200 cm/sec), which confers a higher stroke risk, has not been studied prospectively in a randomized trial. Sparing Conversion to Abnormal TCD Elevation (SCATE #NCT01531387) was an NHLBI-funded Phase III multicenter international clinical trial comparing alternative therapy (hydroxyurea) to standard care (observation) to prevent conversion from conditional to abnormal TCD velocity in children with SCA. SCATE enrolled 38 children from the United States, Jamaica, and Brazil [HbSS (36), HbSβ0-thalassemia (1), and HbSD (1), median age 5.4 years (range, 2.7-9.8)]. Due to slow patient accrual and administrative delays, SCATE was terminated early. In an intention-to-treat analysis, the cumulative incidence of abnormal conversion was 9% (95% CI 0 to 35%) in the hydroxyurea arm and 47% (95% CI 6 to 81%) in observation arm at 15 months (p=0.16). In post-hoc analysis according to treatment received, significantly fewer children on hydroxyurea converted to abnormal TCD velocities, compared to observation (0% versus 50%, p=0.02). After a mean of 10.1 months, a significant change in mean TCD velocity was observed with hydroxyurea treatment (−15.5 versus +10.2 cm/sec, p=0.02). No stroke events occurred in either arm. Hydroxyurea reduces TCD velocities in children with SCA and conditional velocities. PMID:26414435

Prevention of conversion to abnormal transcranial Doppler with hydroxyurea in sickle cell anemia: A Phase III international randomized clinical trial.

PubMed

Hankins, Jane S; McCarville, Mary Beth; Rankine-Mullings, Angela; Reid, Marvin E; Lobo, Clarisse L C; Moura, Patricia G; Ali, Susanna; Soares, Deanne P; Aldred, Karen; Jay, Dennis W; Aygun, Banu; Bennett, John; Kang, Guolian; Goldsmith, Jonathan C; Smeltzer, Matthew P; Boyett, James M; Ware, Russell E

2015-12-01

Children with sickle cell anemia (SCA) and conditional transcranial Doppler (TCD) ultrasound velocities (170-199 cm/sec) may develop stroke. However, with limited available clinical data, the current standard of care for conditional TCD velocities is observation. The efficacy of hydroxyurea in preventing conversion from conditional to abnormal TCD (≥200 cm/sec), which confers a higher stroke risk, has not been studied prospectively in a randomized trial. Sparing Conversion to Abnormal TCD Elevation (SCATE #NCT01531387) was a National Heart, Lung, and Blood Institute-funded Phase III multicenter international clinical trial comparing alternative therapy (hydroxyurea) to standard care (observation) to prevent conversion from conditional to abnormal TCD velocity in children with SCA. SCATE enrolled 38 children from the United States, Jamaica, and Brazil [HbSS (36), HbSβ(0) -thalassemia (1), and HbSD (1), median age = 5.4 years (range, 2.7-9.8)]. Because of the slow patient accrual and administrative delays, SCATE was terminated early. In an intention-to-treat analysis, the cumulative incidence of abnormal conversion was 9% (95% CI = 0-35%) in the hydroxyurea arm and 47% (95% CI = 6-81%) in observation arm at 15 months (P = 0.16). In post hoc analysis according to treatment received, significantly fewer children on hydroxyurea converted to abnormal TCD velocities when compared with observation (0% vs. 50%, P = 0.02). After a mean of 10.1 months, a significant change in mean TCD velocity was observed with hydroxyurea treatment (-15.5 vs. +10.2 cm/sec, P = 0.02). No stroke events occurred in either arm. Hydroxyurea reduces TCD velocities in children with SCA and conditional velocities. © 2015 Wiley Periodicals, Inc.

Development of a pharmacokinetic‐guided dose individualization strategy for hydroxyurea treatment in children with sickle cell anaemia

PubMed Central

Dong, Min; McGann, Patrick T.; Mizuno, Tomoyuki; Ware, Russell E.

2016-01-01

AIMS Hydroxyurea has emerged as the primary disease‐modifying therapy for patients with sickle cell anaemia (SCA). The laboratory and clinical benefits of hydroxyurea are optimal at maximum tolerated dose (MTD), but the current empirical dose escalation process often takes up to 12 months. The purpose of this study was to develop a pharmacokinetic‐guided dosing strategy to reduce the time required to reach hydroxyurea MTD in children with SCA. Methods Pharmacokinetic (PK) data from the HUSTLE trial (NCT00305175) were used to develop a population PK model using non‐linear mixed effects modelling (nonmem 7.2). A D‐optimal sampling strategy was developed to estimate individual PK and hydroxyurea exposure (area under the concentration–time curve (AUC)). The initial AUC target was derived from HUSTLE clinical data and defined as the mean AUC at MTD. Results PK profiles were best described by a one compartment with Michaelis–Menten elimination and a transit absorption model. Body weight and cystatin C were identified as significant predictors of hydroxyurea clearance. The following clinically feasible sampling times are included in a new prospective protocol: pre‐dose (baseline), 15–20 min, 50–60 min and 3 h after an initial 20 mg kg–1 oral dose. The mean target AUC(0,∞) for initial dose titration was 115 mg l–1 h. Conclusion We developed a PK model‐based individualized dosing strategy for the prospective Therapeutic Response Evaluation and Adherence Trial (TREAT, ClinicalTrials.gov NCT02286154). This approach has the potential to optimize the dose titration of hydroxyurea therapy for children with SCA, such that the clinical benefits at MTD are achieved more quickly. PMID:26615061

Cytologic Effects of Air Force Chemicals

DTIC Science & Technology

1978-09-01

pCi/ml, 60 Ci/mmole), hydroxyurea (10- 2M) to suppress replicative DNA synthesis, and with or without 4-nitroquinoline-l-oxide (4NQO, a DNA-damaging...organ cultures. The tissues were minced in cold, buffered saline and then incubated with 3 H-thymidine, hydroxyurea and 4NQO to damage cellular DNA...incorporation under these conditions is taken as an indication of DNA repair activity, and incorporation of 3H-thymidine in the absence of hydroxyurea and

Interaction of N-hydroxyurea with strong proton donors: HCl and HF

NASA Astrophysics Data System (ADS)

Sałdyka, Magdalena

2014-11-01

An infrared spectroscopic and MP2/6-311++G(2d,2p) study of strong hydrogen bonded complexes of N-hydroxyurea (NH2CONHOH) with hydrogen halides (HCl and HF) trapped in solid argon matrices is reported. 1:1 and 1:2 complexes between N-hydroxyurea and hydrogen chloride, hydrogen fluoride have been identified in the NH2CONHOH/HCl/Ar, NH2CONHOH/HF/Ar matrices, respectively; their structures were determined by comparison of the spectra with the results of calculations. In the 1:1 complexes, identified for both hydrogen halide molecules, the cyclic structure stabilized by the X-H⋯O and N-H⋯X bonds is present; for the NH2CONHOH⋯HF system another isomeric 1:1 complex is also observed. Two 1:2 complexes were identified for the N-hydroxyurea-hydrogen chloride system characterised by the Cl-H⋯O and N-H⋯Cl bonds. The results of the study evidence that N-hydroxyurea is an oxygen base in the gas-phase with the carbonyl group as the strongest proton acceptor centre in the molecule.

Pre-treatment with oral hydroxyurea prior to intensive chemotherapy improves early survival of patients with high hyperleukocytosis in acute myeloid leukemia.

PubMed

Mamez, Anne-Claire; Raffoux, Emmanuel; Chevret, Sylvie; Lemiale, Virginie; Boissel, Nicolas; Canet, Emmanuel; Schlemmer, Benoît; Dombret, Hervé; Azoulay, Elie; Lengliné, Etienne

2016-10-01

Acute myeloid leukemia with high white blood cell count (WBC) is a medical emergency. A reduction of tumor burden with hydroxyurea may prevent life-threatening complications induced by straight chemotherapy. To evaluate this strategy, we reviewed medical charts of adult patients admitted to our institution from 1997 to 2011 with non-promyelocytic AML and WBC over 50 G/L. One hundred and sixty patients were included with a median WBC of 120 G/L (range 50-450), 107 patients received hydroxyurea prior to chemotherapy, and 53 received emergency induction chemotherapy (CT). Hospital mortality was lower for patients treated with hydroxyurea (34% versus 19%, p = 0.047) even after adjusting for age (p < 0.01) and initial WBC count (p = 0.02). No evidence of any difference between treatment groups in terms of WBC decline kinetics and disease free survival (p = 0.87) was found. Oral hydroxyurea prior to chemotherapy seems a safe and efficient strategy to reduce early death of hyperleukocytic AML patients.

Hydroxyurea for reducing blood transfusion in non-transfusion dependent beta thalassaemias.

PubMed

Foong, Wai Cheng; Ho, Jacqueline J; Loh, C Khai; Viprakasit, Vip

2016-10-18

Non-transfusion dependent beta thalassaemia is a subset of inherited haemoglobin disorders characterised by reduced production of the beta globin chain of the haemoglobin molecule leading to anaemia of varying severity. Although blood transfusion is not a necessity for survival, it is required when episodes of chronic anaemia occur. This chronic anaemia can impair growth and affect quality of life. People with non-transfusion dependent beta thalassaemia suffer from iron overload due to their body's increased capability of absorbing iron from food sources. Iron overload becomes more pronounced in those requiring blood transfusion. People with a higher foetal haemoglobin level have been found to require fewer blood transfusions. Hydroxyurea has been used to increase foetal haemoglobin level; however, its efficacy in reducing transfusion, chronic anaemia complications and its safety need to be established. To assess the effectiveness, safety and appropriate dose regimen of hydroxyurea in people with non-transfusion dependent beta thalassaemia (haemoglobin E combined with beta thalassaemia and beta thalassaemia intermedia). We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of relevant journals. We also searched ongoing trials registries and the reference lists of relevant articles and reviews.Date of last search: 30 April 2016. Randomised or quasi-randomised controlled trials of hydroxyurea in people with non-transfusion dependent beta thalassaemia comparing hydroxyurea with placebo or standard treatment or comparing different doses of hydroxyurea. Two authors independently applied the inclusion criteria in order to select trials for inclusion. Both authors assessed the risk of bias of trials and extracted the data. A third author verified these assessments. No trials comparing hydroxyurea with placebo or standard care were found. However, we included one randomised controlled trial (n = 61) comparing 20 mg/kg/day with 10 mg/kg/day of hydroxyurea for 24 weeks.Both haemoglobin and foetal haemoglobin levels were lower at 24 weeks in the 20 mg group compared with the 10 mg group, mean difference -2.39 (95% confidence interval - 2.8 to -1.98) and mean difference -1.5 (95% confidence interval -1.83 to -1.17), respectively. Major adverse effects were significantly more common in the 20 mg group, for neutropenia risk ratio 9.93 (95% confidence interval 1.34 to 73.97) and for thrombocytopenia risk ratio 3.68 (95% confidence interval 1.13 to 12.07). No difference was reported for minor adverse effects (gastrointestinal disturbances and raised liver enzymes). The effect of hydroxyurea on transfusion frequency was not reported.The overall quality for the outcomes reported was graded as very low mainly because the outcomes were derived from only one small study with an unclear method of allocation concealment. There is no evidence from randomised controlled trials to show whether hydroxyurea has any effect compared with controls on the need for blood transfusion. Administration of 10 mg/kg/day compared to 20 mg/kg/day of hydroxyurea resulted in higher haemoglobin levels and seems safer with fewer adverse effects. It has not been reported whether hydroxyurea is capable of reducing the need for blood transfusion. Large well-designed randomised controlled trials with sufficient duration of follow up are recommended.

Molecular Analysis of the Inheritance of Transcriptional Silencing

DTIC Science & Technology

2007-04-01

arrest, to synchronize the cells for hydroxyurea (HU) addition, and then released into an alpha factor/0.2M HU arrest (Fig. 1A). 2 hours after release...restrictive conditions to degrade both Sir1td and Asf1td proteins. Cells were then release for 4 hours into 0.2M hydroxyurea (HU), an early S phase arrest...on three experiments. The “Block” row describes the cell cycle inhibitor used in each time point (alpha factor, hydroxyurea and nocodozole). 24

From Infancy to Adolescence: Fifteen Years of Continuous Treatment With Hydroxyurea in Sickle Cell Anemia

PubMed Central

Hankins, Jane S.; Aygun, Banu; Nottage, Kerri; Thornburg, Courtney; Smeltzer, Matthew P.; Ware, Russell E.; Wang, Winfred C.

2014-01-01

Abstract Despite documented laboratory and clinical benefits of hydroxyurea for children with sickle cell anemia (SCA), the drug's long-term safety and efficacy remains poorly defined. The HUSOFT trial and extension study examined feasibility, toxicity, and hematological efficacy of hydroxyurea in infants with SCA. This report describes HUSOFT participants who have continued hydroxyurea therapy for 15 years. With IRB approval, medical records were reviewed for clinical, laboratory, and growth parameters. Twenty-eight infants enrolled in the original 2-year HUSOFT study received open-label liquid hydroxyurea at 20 mg/kg/day; 17 completed the extension study with dose escalation to 30 mg/kg/day. Eight of these 17 (6 girls and 2 boys, all HbSS) have continued on daily hydroxyurea for at least 15 years (median age at last follow-up 17.6 years) without interruption. All hematologic indices (Hb concentration, mean corpuscular volume (MCV), fetal hemoglobin) showed sustained effect after 15 years. The median maximum tolerated dose of hydroxyurea has decreased from 30 to 26 mg/kg/day (range 19.5–31.2); neutropenia [absolute neutrophil count (ANC) < 1.0 × 109/L] prompting temporary drug discontinuation occurred a total of 10 times in 4 subjects and there was no severe neutropenia (ANC < 0.5 × 109/L). Growth rates over 15 years continued at the 50th percentile for both height and weight, and puberty occurred without delay (age range 10–14 years). There were 5.1 vaso-occlusive events (pain and acute chest syndrome)/100 patient years, 7.3 packed red blood cell transfusions/100 patient years. No malignancies, strokes, or deaths occurred. At last follow up, all subjects were at appropriate grade level (10–12 grade) with no history of repeated grades. A cohort of young teenagers with SCA who initiated treatment in infancy have had sustained and continued hematological benefits for a decade and a half. Growth and sexual development are normal and comparable to the general pediatric population. Continuous hydroxyurea therapy since infancy appears safe and efficacious in SCA. PMID:25526439

From infancy to adolescence: fifteen years of continuous treatment with hydroxyurea in sickle cell anemia.

PubMed

Hankins, Jane S; Aygun, Banu; Nottage, Kerri; Thornburg, Courtney; Smeltzer, Matthew P; Ware, Russell E; Wang, Winfred C

2014-12-01

Despite documented laboratory and clinical benefits of hydroxyurea for children with sickle cell anemia (SCA), the drug's long-term safety and efficacy remains poorly defined. The HUSOFT trial and extension study examined feasibility, toxicity, and hematological efficacy of hydroxyurea in infants with SCA. This report describes HUSOFT participants who have continued hydroxyurea therapy for 15 years. With IRB approval, medical records were reviewed for clinical, laboratory, and growth parameters. Twenty-eight infants enrolled in the original 2-year HUSOFT study received open-label liquid hydroxyurea at 20 mg/kg/day; 17 completed the extension study with dose escalation to 30 mg/kg/day. Eight of these 17 (6 girls and 2 boys, all HbSS) have continued on daily hydroxyurea for at least 15 years (median age at last follow-up 17.6 years) without interruption. All hematologic indices (Hb concentration, mean corpuscular volume (MCV), fetal hemoglobin) showed sustained effect after 15 years. The median maximum tolerated dose of hydroxyurea has decreased from 30 to 26 mg/kg/day (range 19.5-31.2); neutropenia [absolute neutrophil count (ANC)<1.0×10⁹/L] prompting temporary drug discontinuation occurred a total of 10 times in 4 subjects and there was no severe neutropenia (ANC<0.5×10⁹/L). Growth rates over 15 years continued at the 50th percentile for both height and weight, and puberty occurred without delay (age range 10-14 years). There were 5.1 vaso-occlusive events (pain and acute chest syndrome)/100 patient years, 7.3 packed red blood cell transfusions/100 patient years. No malignancies, strokes, or deaths occurred. At last follow up, all subjects were at appropriate grade level (10-12 grade) with no history of repeated grades. A cohort of young teenagers with SCA who initiated treatment in infancy have had sustained and continued hematological benefits for a decade and a half. Growth and sexual development are normal and comparable to the general pediatric population. Continuous hydroxyurea therapy since infancy appears safe and efficacious in SCA.

Improved hydroxyurea effect with the use of text messaging in children with sickle cell anemia.

PubMed

Estepp, Jeremie H; Winter, Bryan; Johnson, Margery; Smeltzer, Matthew P; Howard, Scott C; Hankins, Jane S

2014-11-01

In children with sickle cell anemia (SCA), hydroxyurea reduces morbidity, but adherence is frequently suboptimal. Because most families of children with SCA have access to cellular telephone services, we assessed the impact of text messaged reminders as a tool to improve adherence to hydroxyurea. All patients <19 years of age with HbSS or HbSβ(0) thalassemia who were treated with hydroxyurea at a maximal tolerated dosage (MTD) at St. Jude Children's Research Hospital Comprehensive Pediatric Sickle Cell Program and who received automated text message reminders (SIMON®) were retrospectively identified. Laboratory parameters, hospitalizations, and medication possession ratios (MPR) prior to and after initiation of SIMON® were compared to assess the impact of SIMON®. Of the 97.3% of families with access to a cell phone, 91% elected to receive text message reminders. Among 55 children receiving hydroxyurea at MTD, laboratory parameters reflected waning medication compliance during the 12 months prior to SIMON®. Following initiation of SIMON®, children had higher mean corpuscular volumes, hemoglobin levels and fetal hemoglobin percentages and lower absolute reticulocyte counts and bilirubin levels, suggesting improved medication adherence. Hospitalizations were uncommon before and after SIMON®, and medication possession ratios (MPRs) were high before and after SIMON®, neither was significantly changed. SIMON® was feasible and improved hematologic parameters in children with SCA receiving hydroxyurea at a MTD. Future work will include extension of this technology to children with other chronic medical conditions who require daily use of medication. © 2014 Wiley Periodicals, Inc.

Candidate Sequence Variants and Fetal Hemoglobin in Children with Sickle Cell Disease Treated with Hydroxyurea

PubMed Central

Green, Nancy S.; Ender, Katherine L.; Pashankar, Farzana; Driscoll, Catherine; Giardina, Patricia J.; Mullen, Craig A.; Clark, Lorraine N.; Manwani, Deepa; Crotty, Jennifer; Kisselev, Sergey; Neville, Kathleen A.; Hoppe, Carolyn; Barral, Sandra

2013-01-01

Background Fetal hemoglobin level is a heritable complex trait that strongly correlates swith the clinical severity of sickle cell disease. Only few genetic loci have been identified as robustly associated with fetal hemoglobin in patients with sickle cell disease, primarily adults. The sole approved pharmacologic therapy for this disease is hydroxyurea, with effects largely attributable to induction of fetal hemoglobin. Methodology/Principal Findings In a multi-site observational analysis of children with sickle cell disease, candidate single nucleotide polymorphisms associated with baseline fetal hemoglobin levels in adult sickle cell disease were examined in children at baseline and induced by hydroxyurea therapy. For baseline levels, single marker analysis demonstrated significant association with BCL11A and the beta and epsilon globin loci (HBB and HBE, respectively), with an additive attributable variance from these loci of 23%. Among a subset of children on hydroxyurea, baseline fetal hemoglobin levels explained 33% of the variance in induced levels. The variant in HBE accounted for an additional 13% of the variance in induced levels, while variants in the HBB and BCL11A loci did not contribute beyond baseline levels. Conclusions/Significance These findings clarify the overlap between baseline and hydroxyurea-induced fetal hemoglobin levels in pediatric disease. Studies assessing influences of specific sequence variants in these and other genetic loci in larger populations and in unusual hydroxyurea responders are needed to further understand the maintenance and therapeutic induction of fetal hemoglobin in pediatric sickle cell disease. PMID:23409025

A patient case highlighting the myriad of cutaneous adverse effects of prolonged use of hydroxyurea.

PubMed

Neill, Brett; Ryser, Ted; Neill, John; Aires, Daniel; Rajpara, Anand

2017-11-15

Hydroxyurea is an antimetabolite primarily used to treat myeloproliferative disorders, and chronic treatment is associated with many cutaneous adverse effects ranging in severity from ichthyosis to aggressive nonmelanoma skin cancer. We report a 67-year-oldman with a history of polycythemia vera who was referred for management of progressively worsening dorsal hand lesions. The patient presented withhyperpigmentation, ichthyosis, plantar keratoderma, dermatomyositis-like eruptions, two squamous cell carcinomas, and actinic keratoses. The adversereactions observed were acknowledged to be related to chronic hydroxyurea use. The patient underwent Mohs excision of the squamous cell carcinomas and thehydroxyurea was promptly discontinued; subsequent cutaneous improvement of the dermatomyositislike lesions ensued. Another clinically suspicious aggressive squamous cell carcinoma was suspected and the patient was referred to the plastic surgery department for complete excision because of the size of the lesion. The patient remains on periodic dermatology follow up. We report a case that exemplifies the cutaneous adverse effects of chronic hydroxyurea therapy. Although many cases improve after drug discontinuation, strict photoprotection and ongoing surveillance are indicated given the recently proposed premalignant potential of dermatomyositis-like eruptions and the aggressive nature of hydroxyurea-induced nonmelanoma skin cancer.

Hydroxyurea (hydroxycarbamide) for sickle cell disease.

PubMed

Nevitt, Sarah J; Jones, Ashley P; Howard, Jo

2017-04-20

Sickle cell disease (SCD) is one of the most common inherited diseases worldwide. It is associated with lifelong morbidity and a reduced life expectancy. Hydroxyurea (hydroxycarbamide), an oral chemotherapeutic drug, ameliorates some of the clinical problems of SCD, in particular that of pain, by raising fetal haemoglobin. This is an update of a previously published Cochrane Review. To assess the effects of hydroxyurea therapy in people with SCD (all genotypes), of any age, regardless of setting. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Register, comprising of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also searched online trial registries.Date of the most recent search: 16 January 2017. Randomised and quasi-randomised controlled trials, of one month or longer, comparing hydroxyurea with placebo, standard therapy or other interventions for people with SCD. Authors independently assessed studies for inclusion, carried out data extraction and assessed the risk of bias. Seventeen studies were identified in the searches; eight randomised controlled trials were included, recruiting 899 adults and children with SCD (haemoglobin SS (HbSS), haemoglobin SC (HbSC) or haemoglobin Sβºthalassaemia (HbSβºthal) genotypes). Studies lasted from six to 30 months.Four studies (577 adults and children with HbSS or HbSβºthal) compared hydroxyurea to placebo; three recruited individuals with only severe disease and one recruited individuals with all disease severities. There were statistically significant improvements in terms of pain alteration (using measures such as pain crisis frequency, duration, intensity, hospital admissions and opoid use), measures of fetal haemoglobin and neutrophil counts and fewer occurrences of acute chest syndrome and blood transfusions in the hydroxyurea groups. There were no consistent statistically significant differences in terms of quality of life and adverse events (including serious or life-threatening events). Seven deaths occurred during the studies, but the rates by treatment group were not statistically significantly different.Two studies (254 children with HbSS or HbSβºthal also with risk of primary or secondary stroke) compared hydroxyurea and phlebotomy to transfusion and chelation; there were statistically significant improvements in terms of measures of fetal haemoglobin and neutrophil counts, but more occurrences of acute chest syndrome and infections in the hydroxyurea and phlebotomy group. There were no consistent statistically significant differences in terms of pain alteration and adverse events (including serious or life-threatening events). Two deaths occurred during the studies (one in a the hydroxyurea treatment arm and one in the control arm), but the rates by treatment group were not statistically significantly different. In the primary prevention study, no strokes occurred in either treatment group but in the secondary prevention study, seven strokes occurred in the hydroxyurea and phlebotomy group (none in the transfusion and chelation group) and the study was terminated early.The quality of the evidence for the above two comparisons was judged as moderate to low as the studies contributing to these comparisons were mostly large and well designed (and at low risk of bias); however evidence was limited and imprecise for some outcomes such as quality of life, deaths during the studies and adverse events and results are applicable only to individuals with HbSS and HbSβºthal genotypes.Of the remaining two studies, one (22 children with HbSS or HbSβºthal also at risk of stoke) compared hydroxyurea to observation; there were statistically significant improvements in terms of measures of fetal haemoglobin and neutrophil counts but no statistically significant differences in terms of adverse events (including serious or life-threatening events).The final study (44 adults and children with HbSC) compared treatment regimens with and without hydroxyurea - there was statistically significant improvement in terms of measures of fetal haemoglobin, but no statistically significant differences in terms of adverse events (including serious or life-threatening events). No participants died in either of these studies and other outcomes relevant to the review were not reported.The quality of the evidence for the above two comparisons was judged to be very low due to the limited number of participants, the lack of statistical power (as both studies were terminated early with approximately only 20% of their target sample size recruited) and the lack of applicability to all age groups and genotypes. There is evidence to suggest that hydroxyurea is effective in decreasing the frequency of pain episodes and other acute complications in adults and children with sickle cell anaemia of HbSS or HbSβºthal genotypes and in preventing life-threatening neurological events in those with sickle cell anaemia at risk of primary stroke by maintaining transcranial doppler velocities. However, there is still insufficient evidence on the long-term benefits of hydroxyurea, particularly in preventing chronic complications of SCD, recommending a standard dose or dose escalation to maximum tolerated dose. There is also insufficient evidence about the long-term risks of hydroxyurea, including its effects on fertility and reproduction. Evidence is also limited on the effects of hydroxyurea on individuals with HbSC genotype. Future studies should be designed to address such uncertainties.

Predictors of splenic function preservation in children with sickle cell anemia treated with hydroxyurea.

PubMed

Nottage, Kerri A; Ware, Russell E; Winter, Bryan; Smeltzer, Matthew; Wang, Winfred C; Hankins, Jane S; Dertinger, Stephen D; Shulkin, Barry; Aygun, Banu

2014-11-01

More than 90% of children with sickle cell anemia (SCA) lose splenic function by the age of 2 yrs. Splenic function may improve with hydroxyurea, but previous studies are conflicting. We prospectively evaluated the effect of hydroxyurea on splenic filtrative function. Children with SCA enrolled in the Hydroxyurea Study of Long-Term Effects (HUSTLE-NCT00305175) underwent clinical evaluations including Tc(99) m liver-spleen (LS) scans before hydroxyurea initiation and after 3 yrs of treatment to maximum tolerated dose (MTD). LS scans were classified as follows: no uptake, <10% uptake, decreased but ≥10% uptake, and normal. Mean age (N = 40) was 9.1 yrs, range 2.3-17.0. After 3 yrs of treatment, 13 (33%) had uptake on LS scan. These 13 children were younger (median age 6.0 vs. 10.6 yrs, P = 0.008), had a higher HbF at baseline (mean 10.2% vs. 5.8%, P = 0.004) and after 3 yrs (22.9% vs. 13.9%, P < 0.001), achieved MTD more rapidly (median 288 vs. 358 d, P = 0.021), and were more likely to have baseline splenic uptake (P < 0.001). Hydroxyurea at MTD is associated with preserved or improved splenic filtrative function, with 33% demonstrating LS scan uptake after 3 yrs. Younger age, higher %HbF, and baseline splenic function are associated with a favorable outcome. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The case for and against initiating either hydroxyurea therapy, blood transfusion therapy or hematopoietic stem cell transplant in asymptomatic children with sickle cell disease.

PubMed

Kassim, Adetola A; DeBaun, Michael R

2014-02-01

The perception of an asymptomatic sickle cell disease (SCD) state is a misnomer. Children without overt symptoms, likely have subclinical disease beginning in infancy with progression into adulthood. Predictive models of SCD severity are unable to predict a subgroup of asymptomatic children likely to develop severe SCD. The introduction of penicillin prophylaxis, conjugated pneumococcal and Haemophilus influenzae type B vaccines have dramatically decreased the rate of life-threatening infections, while use of hydroxyurea in children has decreased pain and acute chest syndrome events. Use of transcranial Doppler coupled with regular blood transfusion therapy has decreased the rate of overt strokes and premature death associated with strokes. Currently, therapy for asymptomatic children includes hydroxyurea, regular blood transfusion or allogeneic hematopoietic stem cell transplant (allo-HSCT). The pros and cons of initiating hydroxyurea, regular blood transfusion or allo-HSCT in asymptomatic children with SCD. Emerging evidence from observational studies indicates that hydroxyurea prolongs survival in children and adults with sickle cell anemia. Regular blood transfusions reduce incidence of strokes, acute chest and pain episodes, but is associated with the burden of monthly visits and excessive iron stores. Although curative, the perceived risk:benefit ratio associated with allo-HSCT limits its use in asymptomatic children.

Hydroxyurea for Treatment of Nephrotic Syndrome Associated With Polycythemia Vera.

PubMed

Hundemer, Gregory L; Rosales, Ivy A; Chen, Yi-Bin; Colvin, Robert B; Tolkoff-Rubin, Nina E

2016-09-01

Myeloproliferative disorders are a rare cause of focal segmental glomerulosclerosis (FSGS), although the mechanism is unclear. Hydroxyurea is commonly used in these disorders for its cytoreductive properties; however, the effect of this treatment on proteinuria or kidney function remains unclear in cases of myeloproliferative disorder-associated FSGS. We describe the clinical course of a patient with polycythemia vera and nephrotic-range proteinuria, demonstrated to have FSGS on biopsy. The patient had a distant history of granulomatosis with polyangiitis (Wegener's), for which he routinely had his kidney function and proteinuria measured, allowing for early detection of nephrotic syndrome soon after being diagnosed with polycythemia vera. Treatment with hydroxyurea resulted in rapid improvement in proteinuria that correlated with a decrease in hematocrit. This response was replicated 2 additional times when the patient was taken off and then restarted on hydroxyurea therapy. He now maintains a steady dose of hydroxyurea with favorable kidney measures (proteinuria with <1g/d of protein excretion and serum creatinine of 1.27mg/dL [corresponding to estimated glomerular filtration rate of 56mL/min/1.73 m(2)]). This case suggests that early screening and treatment for myeloproliferative disorder-associated FSGS may lead to improved long-standing kidney function. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Real-life experience with hydroxyurea in sickle cell disease: A multicenter study in a cohort of patients with heterogeneous descent.

PubMed

Rigano, Paolo; De Franceschi, Lucia; Sainati, Laura; Piga, Antonio; Piel, Frédéric B; Cappellini, Maria Domenica; Fidone, Carmelo; Masera, Nicoletta; Palazzi, Giovanni; Gianesin, Barbara; Forni, Gian Luca

2018-03-01

We conducted the first nation-wide cohort study of sickle cell disease (SCD) in Italy, a Southern European country exposed to intense recent flux migration from endemic areas for SCD. We evaluate the impact of hydroxyurea on a total of 652 pediatric and adult patients from 33 Reference Centers for SCD (mean age 24.5±15years, 51.4% males). Hydroxyurea median treatment duration was 7years (range: <1year to 29years) at a mean therapeutic dose of 18±4.7mg/kg/day. Hydroxyurea was associated with a significant increase in mean total and fetal hemoglobin and a significant decrease in mean hemoglobin S, white blood and platelet counts, and lactate dehydrogenase levels. Hydroxyurea was associated with a significant reduction in the incidence of acute chest syndrome (-29.3%, p<0.001), vaso-occlusive crisis (-34.1%, p<0.001), hospitalization (-53.2%, p<0.001), and bone necrosis (-6.9%, p<0.001). New silent cerebral infarction (SCI) occurred during treatment (+42.4%, p<0.001) but not stroke (+0.5%, p=0.572). These observations were generally consistent upon stratification for age, descent (Caucasian or African), genotype (βS/βS, βS/β 0 or βS/β + ) and duration of treatment (< or ≥10years). There were no new safety concerns observed compared to those commonly reported in the literature. Our study, conducted on a large population of patients with different descent and compound state supports the benefits of hydroxyurea therapy as a treatment option. Registered at clinical trials.gov (NCT02709681). Copyright © 2017 Elsevier Inc. All rights reserved.

Impact of imatinib interruption and duration of prior hydroxyurea on the treatment outcome in patients with chronic myeloid leukemia: Single institution experience.

PubMed

Edesa, Wael Abdelgawad; Abdel-malek, Raafat Ragaey

2015-06-01

Optimal response requires that patients should be maintained on the drug continuously. To evaluate the influence of imatinib interruption and prior hydroxyurea use on the outcome of patients with chronic myeloid leukemia. Between January 2010 and November 2013, patients with chronic phase who received imatinib at the Kasr Al-ainy Center of Clinical Oncology were included. Sixty patients were included in this study, thirty three patients (55%) received imatinib upfront, while 27 (45%) received imatinib post hydroxyurea. Imatinib was not given regularly in 50% of patients. In terms of response, only major molecular response and complete molecular response were statistically significant in favor of patients who were receiving imatinib regularly compared to those who had interruption (p<0.001, p<0.001, respectively) , while there was no difference in patients stratified according to prior hydroxyurea. The median progression free survival was 30.3 months (95% CI 24.3-36.3). Among the group of patients who received imatinib regularly, progression free survival was longer (p=0.049), there was no difference between those who received prior hydroxyurea versus those who did not (p=0.67). Duration of prior hydroxyurea had no impact on response or progression free survival, while patients regular on imatinib had statistically significant difference with respect to major molecular response, complete molecular response and progression free survival compared to those who had periods of drug interruption, thus we need more governmental support to supply the drug without interruption to improve the outcome of therapy. Copyright © 2015 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

Inhibition of Mutation: A Novel Approach to Preventing and Treating Cancer

DTIC Science & Technology

2007-06-01

Hydroxyurea (HU) is a small molecule chemotherapeutic that is thought to slow tumor growth by inhibiting RNR and thus reducing dNTP...Identification of hydroxyurea as an inhibitor of induced mutation that presumably acts by inhibiting ribonucleotide reductase and thereby decreasing the

Hydroxyurea for the Treatment of Sickle Cell Disease: Efficacy, Barriers, Toxicity, and Management in Children

PubMed Central

Strouse, John J.; Heeney, Matthew M.

2012-01-01

Hydroxyurea is the only approved medication in the United States for the treatment of sickle cell anemia (HbSS) and is widely used in children despite an indication limited to adults. We review the evidence of efficacy and safety in children with reference to pivotal adult studies. This evidence and expert opinion form the basis for recommended guidelines for the use of hydroxyurea in children including indications, dosing, therapeutic and safety monitoring, and interventions to improve adherence. However, there are substantial gaps in our knowledge to be addressed by on-going and planned studies in children. PMID:22517797

Role of Merlin in the Growth and Transformation of Arachnoidal Cells

DTIC Science & Technology

2009-01-01

studies on the chemotherapeutic agent, hydroxyurea , were performed using meningioma cells grown in the galea (25), and tests on celecoxib were performed...Anders M, Kiesewetter F, Marschalek R, Koch UH, Fahlbusch R (1997) Hydroxyurea for treatment of unresectable and recurrent meningiomas. I. Inhibition of

Phase I Pharmacokinetic Study of the VEGFR Tyrosine Kinase Inhibitor Vatalanib (PTK787) plus Imatinib and Hydroxyurea for Malignant Glioma

PubMed Central

Reardon, David A.; Egorin, Merrill J.; Desjardins, Annick; Vredenburgh, James J.; Beumer, Jan H.; Lagattuta, Theodore F.; Gururangan, Sridharan; Herndon, James E.; Salvado, August J.; Friedman, Henry S.

2009-01-01

Background We determined the maximum tolerated dose (MTD) and dose-limiting toxicities (DLT) of the oral vascular endothelial growth factor receptor (VEGFR) inhibitor, vatalanib, when administered with imatinib and hydroxyurea on a continuous daily schedule among recurrent malignant glioma patients. Methods All patients received 500 mg of hydroxyurea twice daily. Imatinib was dosed at 400 mg per day for patients not taking enzyme-inducing antiepileptic drugs (EIAEDs; stratum A) and at 500 mg twice-a-day for patients taking EIAEDs (stratum B). Vatalanib was escalated from 500 mg to 1250 mg twice daily in successive cohorts, independently for each stratum. Pharmacokinetics of each drug were assessed. Results Thirty-seven recurrent patients, including 34 (92%) with glioblastoma and 3 (8%) with grade 3 malignant glioma, were enrolled. Nineteen patients (51%) were taking EIAEDs. The MTD of vatalanib for all patients was 1000 mg twice-a-day. DLTs were hematologic, gastrointestinal, renal and hepatic. No patients developed intracranial hemorrhage. Concurrent administration of imatinib and hydroxyurea did not affect vatalanib exposure, but EIAEDs decreased vatalanib and imatinib plasma exposures. Conclusion Vatalanib doses up to 1000 mg twice-a-day combined with imatinib and hydroxyurea are well tolerated. Strategies to target tumor blood vessel endothelial cells and pericytes by inhibiting VEGFR and PDGFR, respectively, are safe among recurrent malignant glioma patients and may enhance anti-angiogenesis activity. PMID:19248046

A clinically meaningful fetal hemoglobin threshold for children with sickle cell anemia during hydroxyurea therapy.

PubMed

Estepp, Jeremie H; Smeltzer, Matthew P; Kang, Guolian; Li, Chen; Wang, Winfred C; Abrams, Christina; Aygun, Banu; Ware, Russell E; Nottage, Kerri; Hankins, Jane S

2017-12-01

Hydroxyurea has proven clinical benefits and is recommended to be offered to all children with sickle cell anemia (SCA), but the optimal dosing regimen remains controversial. Induction of red blood cell fetal hemoglobin (HbF) by hydroxyurea appears to be dose-dependent. However, it is unknown whether maximizing HbF% improves clinical outcomes. HUSTLE (NCT00305175) is a prospective observational study with a primary goal of describing the long-term clinical effects of hydroxyurea escalated to maximal tolerated dose (MTD) in children with SCA. In 230 children, providing 610 patient-years of follow up, the mean attained HbF% at MTD was >20% for up to 4 years of follow-up. When HbF% values were ≤20%, children had twice the odds of hospitalization for any reason (P < .0001), including vaso-occlusive pain (P < .01) and acute chest syndrome (ACS) (P < .01), and more than four times the odds of admission for fever (P < .001). Thirty day readmission rates were not affected by HbF%. Neutropenia (ANC <1000 × 10 6 /L) was rare (2.3% of all laboratory monitoring), transient, and benign. Therefore, attaining HbF >20% was associated with fewer hospitalizations without significant toxicity. These data support the use of hydroxyurea in children, and suggest that the preferred dosing strategy is one that targets a HbF endpoint >20%. © 2017 Wiley Periodicals, Inc.

The Combined Effects of Pulsed Magnetic Radiation (Diapulse) and Chemotherapy on Tumor Bearing Mice. The Measurement of Rodent Palatal Explants as a Device for Measurement of the Biologic Effects of Nonionic Radiation (EMR)

NASA Technical Reports Server (NTRS)

Regelson, W.; West, B.; Depaola, D. P.

1978-01-01

Simultaneous treatment utilizing pulsed radiowave and cancer chemotherapy significantly extended the life span of mice with Lewis lung transplanted carcinoma. In comparison with nontreated controls, the combination of hydroxyurea and whole body nonionizing EM radiation (at 27.12 MHz) produced differential enhancement of longevity depending on hydroxyurea combined with highest power output achieved by pulsing the radiation 600 times per second; at a 3.9% duty cycle, peak watts = 975 produced the mean extension of life 67% greater than that of the group treated with hydroxyurea alone.

Multicentre phase II studies evaluating imatinib plus hydroxyurea in patients with progressive glioblastoma.

PubMed

Reardon, D A; Dresemann, G; Taillibert, S; Campone, M; van den Bent, M; Clement, P; Blomquist, E; Gordower, L; Schultz, H; Raizer, J; Hau, P; Easaw, J; Gil, M; Tonn, J; Gijtenbeek, A; Schlegel, U; Bergstrom, P; Green, S; Weir, A; Nikolova, Z

2009-12-15

We evaluated the efficacy of imatinib mesylate in addition to hydroxyurea in patients with recurrent glioblastoma (GBM) who were either on or not on enzyme-inducing anti-epileptic drugs (EIAEDs). A total of 231 patients with GBM at first recurrence from 21 institutions in 10 countries were enrolled. All patients received 500 mg of hydroxyurea twice a day. Imatinib was administered at 600 mg per day for patients not on EIAEDs and at 500 mg twice a day if on EIAEDs. The primary end point was radiographic response rate and secondary end points were safety, progression-free survival at 6 months (PFS-6), and overall survival (OS). The radiographic response rate after centralised review was 3.4%. Progression-free survival at 6 months and median OS were 10.6% and 26.0 weeks, respectively. Outcome did not appear to differ based on EIAED status. The most common grade 3 or greater adverse events were fatigue (7%), neutropaenia (7%), and thrombocytopaenia (7%). Imatinib in addition to hydroxyurea was well tolerated among patients with recurrent GBM but did not show clinically meaningful anti-tumour activity.

Clinic Attendance of Youth With Sickle Cell Disease on Hydroxyurea Treatment.

PubMed

Ingerski, Lisa M; Arnold, Trisha L; Banks, Gabrielle; Porter, Jerlym S; Wang, Winfred C

2017-07-01

The objective of this study is to describe rates of clinic attendance of youth with sickle cell disease prescribed hydroxyurea and examine potential demographic and medical factors related to consistent clinic attendance. Participants included 148 youth diagnosed with sickle cell disease and prescribed hydroxyurea during a single calendar year. Clinic attendance and potential demographic and medical factors related to attendance were extracted via systematic retrospective medical chart review. Youth attended 90.3% of scheduled appointments and 85.1% of youth attended at least 80% of scheduled clinic appointments during the study window. Adjusting for other factors, multivariate analysis revealed families with fewer children in the household, families with private insurance, youth experiencing fever, and youth not experiencing pain during the calendar year were more likely to consistently attend clinic visits. Adherence to clinic appointments is critical to optimizing health outcomes for youth with sickle cell disease and integral for adequate monitoring of youth prescribed hydroxyurea, in particular. Findings may aid providers in appropriately identifying possible barriers to clinic attendance to develop attendance promotion interventions.

Hydroxyurea in Pediatric Patients With Sickle Cell Disease: What Nurses Need to Know.

PubMed

Rees, Allison L

2016-09-01

Sickle cell disease (SCD) is an inherited disorder in which sickled red blood cells occlude the small vessels of the body, reducing oxygen delivery to tissues and ultimately negatively affecting many of the body's major organs. Hydroxyurea has proven beneficial in the treatment of SCD and prevention of disease-related complications. The 2014 guidelines put forth by the National Heart, Lung, and Blood Institute recommend hydroxyurea treatment in infants 9 months and older, children, and adolescents with SCD-SS or SCD-Sβ(0) thalassemia regardless of clinical severity. This is a change from the 2002 guidelines in which hydroxyurea was recommended for adolescents and children with SCD-SS or SCD-Sβ(0) thalassemia with frequent episodes of pain, a history of acute chest syndrome, severe and symptomatic anemia or other severe vaso-occlusive events. Nurses play a critical role in working with patients and families to provide education, guidance, and support to improve compliance to mitigate the long-term effects of SCD. © 2015 by Association of Pediatric Hematology/Oncology Nurses.

Phase II study of imatinib mesylate plus hydroxyurea in adults with recurrent glioblastoma multiforme.

PubMed

Reardon, David A; Egorin, Merrill J; Quinn, Jennifer A; Rich, Jeremy N; Rich, Jeremy N; Gururangan, Sridharan; Gururangan, Idharan; Vredenburgh, James J; Desjardins, Annick; Sathornsumetee, Sith; Provenzale, James M; Herndon, James E; Dowell, Jeannette M; Badruddoja, Michael A; McLendon, Roger E; Lagattuta, Theodore F; Kicielinski, Kimberly P; Dresemann, Gregor; Sampson, John H; Friedman, Allan H; Salvado, August J; Friedman, Henry S

2005-12-20

We performed a phase II study to evaluate the combination of imatinib mesylate, an adenosine triphosphate mimetic, tyrosine kinase inhibitor, plus hydroxyurea, a ribonucleotide reductase inhibitor, in patients with recurrent glioblastoma multiforme (GBM). Patients with GBM at any recurrence received imatinib mesylate plus hydroxyurea (500 mg twice a day) orally on a continuous, daily schedule. The imatinib mesylate dose was 500 mg twice a day for patients on enzyme-inducing antiepileptic drugs (EIAEDs) and 400 mg once a day for those not on EIAEDs. Assessments were performed every 28 days. The primary end point was 6-month progression-free survival (PFS). Thirty-three patients enrolled with progressive disease after prior radiotherapy and at least temozolomide-based chemotherapy. With a median follow-up of 58 weeks, 27% of patients were progression-free at 6 months, and the median PFS was 14.4 weeks. Three patients (9%) achieved radiographic response, and 14 (42%) achieved stable disease. Cox regression analysis identified concurrent EIAED use and no more than one prior progression as independent positive prognostic factors of PFS. The most common toxicities included grade 3 neutropenia (16%), thrombocytopenia (6%), and edema (6%). There were no grade 4 or 5 events. Concurrent EIAED use lowered imatinib mesylate exposure. Imatinib mesylate clearance was decreased at day 28 compared with day 1 in all patients, suggesting an effect of hydroxyurea. Imatinib mesylate plus hydroxyurea is well tolerated and associated with durable antitumor activity in some patients with recurrent GBM.

Barriers to hydroxyurea adherence and health-related quality of life in adolescents and young adults with sickle cell disease.

PubMed

Badawy, Sherif M; Thompson, Alexis A; Penedo, Frank J; Lai, Jin-Shei; Rychlik, Karen; Liem, Robert I

2017-06-01

To identify barriers to hydroxyurea adherence (negative beliefs, access, and/or recall barriers), and their relationship to adherence rates and health-related quality of life (HRQOL) among adolescents and young adults (AYA) with sickle cell disease (SCD). A cross-sectional survey was administered to 34 AYAs (12-22 years old) in SCD clinics from January to December 2015. Study measures included Brief Medication Questionnaire, Modified Morisky Adherence Scale 8-items, visual analog scale, and Patient Reported Outcomes Measurement Information System. Participants (59% male; 91% Black) had a median age of 13.5 years (IQR 12-18). Participants reported negative beliefs (32%), recall barriers (44%), and access barriers (32%). Participants with recall barriers reported worse pain (P=.02), fatigue (P=.05), and depression (P=.05). The number of adherence barriers inversely correlated with adherence level using ©MMAS-8 (r s =-.38, P=.02) and VAS dose (r s =-.25, P=.14) as well as MCV (r s =-.45, P=.01) and HbF% (r s =-.36, P=.05), suggesting higher hydroxyurea adherence in patients with fewer barriers. Patients with fewer barriers to hydroxyurea adherence were more likely to have higher adherence rates and better HRQOL scores. Routine assessment of hydroxyurea adherence and its related barriers could provide actionable information to improve adherence rates, HRQOL, and other clinical outcomes. © 2017 The Authors. European Journal of Haematology Published by John Wiley & Sons Ltd.

Hydroxyurea therapy in UK children with sickle cell anaemia: A single-centre experience.

PubMed

Phillips, Kate; Healy, Laura; Smith, Louise; Keenan, Russell

2018-02-01

Despite the demonstrated efficacy of hydroxyurea therapy, children with sickle cell anaemia in the UK are preferentially managed with supportive care or transfusion. Hydroxyurea is reserved for children with severe disease phenotype. This is in contrast to North America and other countries where hydroxyurea is widely used for children of all clinical phenotypes. The conservative UK practice may in part be due to concerns about toxicity, in particular marrow suppression with high doses, and growth in children. We monitored 37 paediatric patients with sickle cell anaemia who were treated with hydroxyurea at a single UK treatment centre. Therapy was well tolerated and mild transient cytopenias were the only toxicity observed. Comparative analysis of patients receiving ≥26 mg/kg/day versus <26 mg/kg/day demonstrates increasing dose has a significant positive effect on foetal haemoglobin (Hb; 29.2% vs. 20.4%, P = 0.0151), mean cell volume (94.4 vs. 86.5, P = 0.0183) and reticulocyte count (99.66 × 10 9 /l vs. 164.3 × 10 9 /l, P = 0.0059). Marrow suppression was not a clinical problem with high-dose treatment, Hb 92.25 g/l versus 91.81 g/l (ns), neutrophil count 3.3 × 10 9 /l versus 4.8 × 10 9 /l (ns) and platelet count 232.4 × 10 9 /l versus 302.2 × 10 9 /l (ns). Normal growth rates were maintained in all children. Good adherence to therapy was a significant factor in reducing hospitalisations. This study demonstrates the effectiveness and safety in practice of high-dose hydroxyurea as a disease-modifying therapy, which we advocate for all children with sickle cell anaemia. © 2017 The Authors. Pediatric Blood & Cancer Published by Wiley Periodicals, Inc.

TCD With Transfusions Changing to Hydroxyurea (TWiTCH): a multicentre, randomised controlled trial

PubMed Central

Ware, Russell E.; Davis, Barry R.; Schultz, William H.; Brown, R. Clark; Aygun, Banu; Sarnaik, Sharada; Odame, Isaac; Fuh, Beng; George, Alex; Owen, William; Luchtman-Jones, Lori; Rogers, Zora R.; Hilliard, Lee; Gauger, Cynthia; Piccone, Connie; Lee, Margaret T.; Kwiatkowski, Janet L.; Jackson, Sherron; Miller, Scott T.; Roberts, Carla; Heeney, Matthew M.; Kalfa, Theodosia A.; Nelson, Stephen; Imran, Hamayun; Nottage, Kerri; Alvarez, Ofelia; Rhodes, Melissa; Thompson, Alexis A.; Rothman, Jennifer A.; Helton, Kathleen J.; Roberts, Donna; Coleman, Jamie; Bonner, Melanie J.; Kutlar, Abdullah; Patel, Niren; Wood, John; Piller, Linda; Wei, Peng; Luden, Judy; Mortier, Nicole A.; Stuber, Susan E.; Luban, Naomi L. C.; Cohen, Alan R.; Pressel, Sara; Adams, Robert J.

2017-01-01

Background For children with sickle cell anaemia and elevated transcranial Doppler (TCD) flow velocities, regular blood transfusions effectively prevent primary stroke, but must be continued indefinitely. The efficacy of hydroxyurea in this setting is unknown. Methods TWiTCH was a multicentre Phase III randomised open label, non-inferiority trial comparing standard treatment (transfusions) to alternative treatment (hydroxyurea) in children with abnormal TCD velocities but no severe vasculopathy. Iron overload was managed with chelation (Standard Arm) and serial phlebotomy (Alternative Arm). The primary study endpoint was the 24-month TCD velocity calculated from a general linear mixed model, with non-inferiority margin = 15 cm/sec. Findings Among 121 randomised participants (61 transfusions, 60 hydroxyurea), children on transfusions maintained <30% sickle haemoglobin, while those taking hydroxyurea (mean 27 mg/kg/day) averaged 25% fetal haemoglobin. The first scheduled interim analysis demonstrated non-inferiority, and the sponsor terminated the study. Final model-based TCD velocities (mean ± standard error) on Standard versus Alternative Arm were 143 ± 1.6 and 138 ± 1.6 cm/sec, respectively, with difference (95% CI) = 4.54 (0.10, 8.98), non-inferiority p=8.82 × 10−16 and post-hoc superiority p=0.023. Among 29 new neurological events adjudicated centrally by masked reviewers, no strokes occurred but there were 3 transient ischaemic attacks per arm. Exit brain MRI/MRA revealed no new cerebral infarcts in either arm, but worse vasculopathy in one participant (Standard Arm). Iron burden decreased more in the Alternative Arm, with ferritin difference −1047 ng/mL (−1524, −570), p<0.001 and liver iron difference −4.3 mg Fe/gm dry weight (−6.1, −2.5), p=0.001. Interpretation For high-risk children with sickle cell anaemia and abnormal TCD velocities, after four years of transfusions and without severe MRA vasculopathy, hydroxyurea therapy can substitute for chronic transfusions to maintain TCD velocities and help prevent primary stroke. PMID:26670617

Realizing effectiveness across continents with hydroxyurea: Enrollment and baseline characteristics of the multicenter REACH study in Sub-Saharan Africa.

PubMed

McGann, Patrick T; Williams, Thomas N; Olupot-Olupot, Peter; Tomlinson, George A; Lane, Adam; Luís Reis da Fonseca, José; Kitenge, Robert; Mochamah, George; Wabwire, Ham; Stuber, Susan; Howard, Thad A; McElhinney, Kathryn; Aygun, Banu; Latham, Teresa; Santos, Brígida; Tshilolo, Léon; Ware, Russell E

2018-08-01

Despite its well-described safety and efficacy in the treatment of sickle cell anemia (SCA) in high-income settings, hydroxyurea remains largely unavailable in sub-Saharan Africa, where more than 75% of annual SCA births occur and many comorbidities exist. Realizing Effectiveness Across Continents with Hydroxyurea (REACH, ClinicalTrials.gov NCT01966731) is a prospective, Phase I/II open-label trial of hydroxyurea designed to evaluate the feasibility, safety, and benefits of hydroxyurea treatment for children with SCA in four sub-Saharan African countries. Following comprehensive training of local research teams, REACH was approved by local Ethics Committees and achieved full enrollment ahead of projections with 635 participants enrolled over a 30-month period, despite half of families living >12 km from their clinical site. At enrollment, study participants (age 5.4 ± 2.4 years) had substantial morbidity, including a history of vaso-occlusive pain (98%), transfusion (68%), malaria (85%), and stroke (6%). Significant differences in laboratory characteristics were noted across sites, with lower hemoglobin concentrations (P < .01) in Angola (7.2 ± 1.0 g/dL) and the DRC (7.0 ± 0.9 g/dL) compared to Kenya (7.4 ± 1.1 g/dL) and Uganda (7.5 ± 1.1 g/dL). Analysis of known genetic modifiers of SCA demonstrated a high frequency of α-thalassemia (58.4% with at least a single α-globin gene deletion) and G6PD deficiency (19.7% of males and 2.4% of females) across sites. The CAR β-globin haplotype was present in 99% of participants. The full enrollment to REACH confirms the feasibility of conducting high-quality SCA research in Africa; this study will provide vital information to guide safe and effective dosing of hydroxyurea for children with SCA living in Africa. © 2018 Wiley Periodicals, Inc.

Hydroxyurea enhances the activity of acyclovir and cidofovir against herpes simplex virus type 1 resistant strains harboring mutations in the thymidine kinase and/or the DNA polymerase genes.

PubMed

Sergerie, Yan; Boivin, Guy

2008-01-01

Drug-resistant herpes simplex virus type 1 (HSV-1) recombinant strains harboring mutations in the thymidine kinase and/or the DNA polymerase genes were evaluated for their susceptibility to various antivirals in the presence of 25 microg/ml of hydroxyurea (HyU). The latter compound decreased the 50% inhibitory concentrations of acyclovir by 1.5-3.8-fold and that of cidofovir by 2.7-14.4-fold. However, HyU did not affect the susceptibilities of the various recombinant mutants to foscarnet. Hydroxyurea, a ribonucleotide reductase inhibitor, can increase the activity of nucleoside/nucleotide analogues against drug-resistant viruses.

Assessment of rotation thromboelastometry parameters in patients with essential thrombocythemia at diagnosis and after hydroxyurea therapy.

PubMed

Treliński, Jacek; Okońska, Marta; Robak, Marta; Chojnowski, Krzysztof

2016-03-01

Patients with essential thrombocythemia suffer from thrombotic complications that are the main source of mortality. Due to its complex pathogenesis, no existing single laboratory method is able to identify the patients at highest risk for developing thrombosis. Twenty patients with essential thrombocythemia at diagnosis, 15 healthy volunteers and 20 patients treated with hydroxyurea were compared with regard to certain rotation thromboelastometry parameters. Clotting time (CT), clot formation time (CFT), α-angle, and maximum clot firmness (MCF) were assessed by using the INTEM, EXTEM, FIBTEM, and NATEM tests. Patients with essential thrombocythemia at diagnosis demonstrated significantly higher mean platelet count and markedly lower mean red blood count than controls. CT and CFT readings were found to be markedly lower in essential thrombocythemia patients at diagnosis than in the control group according to the EXTEM test. Patients at diagnosis had markedly lower CT values (EXTEM, FIBTEM) than patients on hydroxyurea therapy. Alpha angle values were markedly higher in essential thrombocythemia patients at diagnosis than in controls, according to the EXTEM, FIBTEM and NATEM tests. MCF readings were significantly higher in essential thrombocythemia patients at diagnosis than in controls according to EXTEM, INTEM, FIBTEM, and NATEM tests. Patients on hydroxyurea therapy had markedly lower MCF values according to EXTEM test than patients at diagnosis. Patients with essential thrombocythemia demonstrate a prothrombotic state at the time of diagnosis, which is reflected in changes by certain rotation thromboelastometry parameters. The hydroxyurea therapy induces downregulation of the prothrombotic features seen in essential thrombocythemia patients at diagnosis.

Phase II study of Gleevec® plus hydroxyurea in adults with progressive or recurrent low-grade glioma1

PubMed Central

Reardon, David A.; Desjardins, Annick; Vredenburgh, James J.; Herndon, James E.; Coan, April; Gururangan, Sridharan; Peters, Katherine B.; McLendon, Roger; Sathornsumetee, Sith; Rich, Jeremy N.; Lipp, Eric S.; Janney, Dorothea; Friedman, Henry S.

2013-01-01

Background We evaluated the efficacy of imatinib plus hydroxyurea in patients with progressive/recurrent low-grade glioma. Methods A total of 64 patients with recurrent/progressive low-grade glioma were enrolled in this single-center study that stratified patients into astrocytoma and oligodendroglioma cohorts. All patients received 500 mg of hydroxyurea twice a day. Imatinib was administered at 400 mg per day for patients not on EIAEDs and at 500 mg twice a day if on EIAEDs. The primary endpoint was progression-free survival at 12 months (PFS-12) and secondary endpoints were safety, median progression-free survival and radiographic response rate. Results Thirty-two patients were enrolled into each cohort. Eleven patients (17%) had prior radiotherapy and 24 (38%) had received prior chemotherapy. The median PFS and PFS-12 were 11 months and 39%, respectively. Outcome did not differ between the histologic cohorts. No patient achieved a radiographic response. The most common grade 3 or greater adverse events were neutropenia (11%), thrombocytopenia (3%) and diarrhea (3%). Conclusions Imatinib plus hydroxyurea was well tolerated among recurrent/progressive LGG patients but this regimen demonstrated negligible anti-tumor activity. PMID:22371319

Multicentre phase II studies evaluating imatinib plus hydroxyurea in patients with progressive glioblastoma

PubMed Central

Reardon, D A; Dresemann, G; Taillibert, S; Campone, M; van den Bent, M; Clement, P; Blomquist, E; Gordower, L; Schultz, H; Raizer, J; Hau, P; Easaw, J; Gil, M; Tonn, J; Gijtenbeek, A; Schlegel, U; Bergstrom, P; Green, S; Weir, A; Nikolova, Z

2009-01-01

Background: We evaluated the efficacy of imatinib mesylate in addition to hydroxyurea in patients with recurrent glioblastoma (GBM) who were either on or not on enzyme-inducing anti-epileptic drugs (EIAEDs). Methods: A total of 231 patients with GBM at first recurrence from 21 institutions in 10 countries were enrolled. All patients received 500 mg of hydroxyurea twice a day. Imatinib was administered at 600 mg per day for patients not on EIAEDs and at 500 mg twice a day if on EIAEDs. The primary end point was radiographic response rate and secondary end points were safety, progression-free survival at 6 months (PFS-6), and overall survival (OS). Results: The radiographic response rate after centralised review was 3.4%. Progression-free survival at 6 months and median OS were 10.6% and 26.0 weeks, respectively. Outcome did not appear to differ based on EIAED status. The most common grade 3 or greater adverse events were fatigue (7%), neutropaenia (7%), and thrombocytopaenia (7%). Conclusions: Imatinib in addition to hydroxyurea was well tolerated among patients with recurrent GBM but did not show clinically meaningful anti-tumour activity. PMID:19904263

Alpha-thalassaemia and response to hydroxyurea in sickle cell anaemia.

PubMed

Darbari, Deepika S; Nouraie, Mehdi; Taylor, James G; Brugnara, Carlo; Castro, Oswaldo; Ballas, Samir K

2014-04-01

Hydroxyurea (HU) reduces vaso-occlusive crises (VOC) and other complications of sickle cell anaemia (SCA). Alpha-thalassaemia is a known modifier of SCA. Studies on the efficacy of HU in SCA patients with α-thalassaemia have yielded varying results. To determine the effect of α-thalassaemia in response to HU therapy in the Multicenter Study of Hydroxyurea (MSH) cohort. We compared the laboratory parameters and VOC incidence in the MSH cohort stratified by the presence or the absence of α-thalassaemia. Hydroxyurea showed significant (P = 0.001 for all baseline vs. follow-up comparisons) treatment effect on red cell indices irrespective of α-globin gene deletion. The magnitude of the HU-related changes was similar for mean corpuscular volume (MCV) (no α-thalassaemia 13 fl and α-thalassaemia 13 fl) and mean corpuscular haemoglobin (MCH) (no α-thalassaemia 4 pg and α-thalassaemia 4 pg) in both groups. Foetal haemoglobin (HbF) and F-cells also increased significantly with HU treatment in both groups. Total haemoglobin increased after HU treatment in both groups, but the increase was smaller and not statistically significant in patients with α-thalassaemia. In contrast, HU-related reduction in VOCs was more pronounced in patients with α-thalassaemia (VOC incidence rate ratio HU/placebo: 0.63 for α-thalassaemia and 0.54 for no α-thalassaemia (P for interaction 0.003). Hydroxyurea decreases VOCs in SCA patients with and without α-thalassaemia, and the degree of VOC reduction was more pronounced in the patients with alpha-thalassaemia. Despite the lower baseline values, changes in standard laboratory parameters such as MCV and HbF percent remain useful in monitoring HU therapy in the presence of α-thalassaemia. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Low and fixed dose of hydroxyurea is effective and safe in patients with HbSβ(+) thalassemia with IVS1-5(G→C) mutation.

PubMed

Dehury, Snehadhini; Purohit, Prasanta; Patel, Siris; Meher, Satyabrata; Kullu, Bipin Kishore; Sahoo, Lulup Kumar; Patel, Nayan Kumar; Mohapatra, Alok Kumar; Das, Kishalaya; Patel, Dilip Kumar

2015-06-01

Despite compelling evidence that hydroxyurea is safe and effective in sickle cell disease, it is prescribed sparingly due to several barriers like knowledge gaps in certain genotypes, apprehension about its safety and toxicity, and limited resources. We undertook this study to find out the efficacy and safety of HU in patients with HbSβ(+) -thalassemia with IVS1-5(G→C) mutation. We registered 318 patients with HbSβ(+) -thalassemia with IVS1-5(G→C) mutation. Of these, 203 were enrolled for hydroxyurea treatment at a low and fixed dose of 10 mg/kg/day. One hundred four patients (Group-I: 37 children and Group-II: 67 adults) with ≥2 years of hydroxyurea treatment were studied. The rate of vaso-occlusive crises, requirement of blood transfusion and rate of hospitalization reduced from 3 to 0.5, 1 to 0 and 1 to 0 in Group-I and 3 to 0, 1 to 0 and 0.5 to 0 in Group-II respectively after HU therapy (P < 0.0001). %HbF level, hemoglobin, MCV and MCH increased significantly, whereas HbS, WBC, platelet count, serum-bilirubin and LDH levels decreased significantly after HU therapy. It has been observed that along with fairly subtle hematological changes following HU therapy, there was a substantial clinical improvement occurred in these patients. Transient myelotoxicity was observed in 4.8%. There was minimal gonadal toxicity without affecting reproductive function. In view of easy affordability, better acceptability, minimal toxicity, the need of infrequent monitoring and its potential effectiveness, low and fixed dose of hydroxyurea is suitable for treatment of patients with HbSβ(+) -thalassemia in resource poor setting. © 2014 Wiley Periodicals, Inc.

Class I Histone Deacetylase HDAC1 and WRN RECQ Helicase Contribute Additively to Protect Replication Forks upon Hydroxyurea-induced Arrest.

PubMed

Kehrli, Keffy; Phelps, Michael; Lazarchuk, Pavlo; Chen, Eleanor; Monnat, Ray; Sidorova, Julia M

2016-11-18

The WRN helicase/exonuclease is mutated in Werner syndrome of genomic instability and premature aging. WRN-depleted fibroblasts, although remaining largely viable, have a reduced capacity to maintain replication forks active during a transient hydroxyurea-induced arrest. A strand exchange protein, RAD51, is also required for replication fork maintenance, and here we show that recruitment of RAD51 to stalled forks is reduced in the absence of WRN. We performed a siRNA screen for genes that are required for viability of WRN-depleted cells after hydroxyurea treatment, and identified HDAC1, a member of the class I histone deacetylase family. One of the functions of HDAC1, which it performs together with a close homolog HDAC2, is deacetylation of new histone H4 deposited at replication forks. We show that HDAC1 depletion exacerbates defects in fork reactivation and progression after hydroxyurea treatment observed in WRN- or RAD51-deficient cells. The additive WRN, HDAC1 loss-of-function phenotype is also observed with a catalytic mutant of HDAC1; however, it does not correlate with changes in histone H4 deacetylation at replication forks. On the other hand, inhibition of histone deacetylation by an inhibitor specific to HDACs 1-3, CI-994, correlates with increased processing of newly synthesized DNA strands in hydroxyurea-stalled forks. WRN co-precipitates with HDAC1 and HDAC2. Taken together, our findings indicate that WRN interacts with HDACs 1 and 2 to facilitate activity of stalled replication forks under conditions of replication stress. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Genomic variants in the ASS1 gene, involved in the nitric oxide biosynthesis and signaling pathway, predict hydroxyurea treatment efficacy in compound sickle cell disease/β-thalassemia patients.

PubMed

Chalikiopoulou, Constantina; Tavianatou, Anastasia-Gerasimoula; Sgourou, Argyro; Kourakli, Alexandra; Kelepouri, Dimitra; Chrysanthakopoulou, Maria; Kanelaki, Vasiliki-Kaliopi; Mourdoukoutas, Evangelos; Siamoglou, Stavroula; John, Anne; Symeonidis, Argyris; Ali, Bassam R; Katsila, Theodora; Papachatzopoulou, Adamantia; Patrinos, George P

2016-03-01

Hemoglobinopathies exhibit a remarkable phenotypic diversity that restricts any safe association between molecular pathology and clinical outcomes. Herein, we explored the role of genes involved in the nitric oxide biosynthesis and signaling pathway, implicated in the increase of fetal hemoglobin levels and response to hydroxyurea treatment, in 119 Hellenic patients with β-type hemoglobinopathies. We show that two ASS1 genomic variants (namely, rs10901080 and rs10793902) can serve as pharmacogenomic biomarkers to predict hydroxyurea treatment efficacy in sickle cell disease/β-thalassemia compound heterozygous patients. These markers may exert their effect by inducing nitric oxide biosynthesis, either via altering splicing and/or miRNA binding, as predicted by in silico analysis, and ultimately, increase γ-globin levels, via guanylyl cyclase targeting.

Ruxolitinib for the treatment of inadequately controlled polycythemia vera without splenomegaly: 80-week follow-up from the RESPONSE-2 trial.

PubMed

Griesshammer, Martin; Saydam, Guray; Palandri, Francesca; Benevolo, Giulia; Egyed, Miklos; Callum, Jeannie; Devos, Timothy; Sivgin, Serdar; Guglielmelli, Paola; Bensasson, Caroline; Khan, Mahmudul; Ronco, Julian Perez; Passamonti, Francesco

2018-05-27

RESPONSE-2 is a phase 3 study comparing the efficacy and safety of ruxolitinib with the best available therapy (BAT) in hydroxyurea-resistant/hydroxyurea-intolerant polycythemia vera (PV) patients without palpable splenomegaly. This analysis evaluated the durability of the efficacy and safety of ruxolitinib after patients completed the visit at week 80 or discontinued the study. Endpoints included proportion of patients achieving hematocrit control (< 45%), proportion of patients achieving complete hematologic remission (CHR) at week 28, and the durability of hematocrit control and CHR. At the time of analysis, 93% (69/74) of patients randomized to ruxolitinib were receiving ruxolitinib; while in the BAT arm, 77% (58/75) of patients crossed over to ruxolitinib after week 28. No patient remained on BAT by week 80. Among patients who achieved a hematocrit response at week 28, the probability of maintaining response up to week 80 was 78% in the ruxolitinib arm. At week 80, durable CHR was achieved in 18 patients (24%) in the ruxolitinib arm versus 2 patients (3%) in the BAT arm. The safety profile of ruxolitinib was consistent with previous reports. These data support that ruxolitinib treatment should be considered also as a standard of care for hydroxyurea-resistant/hydroxyurea-intolerant PV patients without palpable splenomegaly.

Phase II study of Gleevec® plus hydroxyurea (HU) in adults with progressive or recurrent meningioma.

PubMed

Reardon, David A; Norden, Andrew D; Desjardins, Annick; Vredenburgh, James J; Herndon, James E; Coan, April; Sampson, John H; Gururangan, Sridharan; Peters, Katherine B; McLendon, Roger E; Norfleet, Julie A; Lipp, Eric S; Drappatz, Jan; Wen, Patrick Y; Friedman, Henry S

2012-01-01

We prospectively evaluated the efficacy and safety of imatinib plus hydroxyurea in patients with progressive/recurrent meningioma. A total of 21 patients with progressive/recurrent meningioma were enrolled in this dual center, single-arm, phase II trial. All patients received 500 mg of hydroxyurea twice a day. Imatinib was administered at 400 mg/day for patients not on CYP3A enzyme inducing anti-epileptic drugs (EIAEDs) and at 500 mg twice a day for patients on EIAEDs. The primary endpoint was progression-free survival at 6 months (PFS-6) and secondary endpoints were safety, radiographic response rate, and overall survival (OS). Best radiographic response was stable disease and was observed in 14 patients (67%). PFS-6 for all patients, those with grade I tumors (n = 8) and those with grade II or III tumors (n = 13) was 61.9, 87.5 and 46.2%, respectively. Patients with grade II or III tumors had poorer PFS and OS than those with grade I tumors, (P = 0.025 and P = 0.018) respectively. The only grade 3 or greater adverse event occurring in ≥ 10% of patients was anemia (10%). Imatinib plus hydroxyurea is well tolerated among patients with meningioma but has modest anti-tumor activity for this indication.

Phase II study of Gleevec® plus hydroxyurea (HU) in adults with progressive or recurrent meningioma

PubMed Central

Norden, Andrew D.; Desjardins, Annick; Vredenburgh, James J.; Herndon, James E.; Coan, April; Sampson, John H.; Gururangan, Sridharan; Peters, Katherine B.; McLendon, Roger E.; Norfleet, Julie A.; Lipp, Eric S.; Drappatz, Jan; Wen, Patrick Y.; Friedman, Henry S.

2011-01-01

We prospectively evaluated the efficacy and safety of imatinib plus hydroxyurea in patients with progressive/recurrent meningioma. A total of 21 patients with progressive/recurrent meningioma were enrolled in this dual center, single-arm, phase II trial. All patients received 500 mg of hydroxyurea twice a day. Imatinib was administered at 400 mg/day for patients not on CYP3A enzyme inducing anti-epileptic drugs (EIAEDs) and at 500 mg twice a day for patients on EIAEDs. The primary endpoint was progression-free survival at 6 months (PFS-6) and secondary endpoints were safety, radiographic response rate, and overall survival (OS). Best radiographic response was stable disease and was observed in 14 patients (67%). PFS-6 for all patients, those with grade I tumors (n = 8) and those with grade II or III tumors (n = 13) was 61.9, 87.5 and 46.2%, respectively. Patients with grade II or III tumors had poorer PFS and OS than those with grade I tumors, (P = 0.025 and P = 0.018) respectively. The only grade 3 or greater adverse event occurring in ≥10% of patients was anemia (10%). Imatinib plus hydroxyurea is well tolerated among patients with meningioma but has modest anti-tumor activity for this indication. PMID:21938530

Exploring alternative Zn-binding groups in the design of HDAC inhibitors: squaric acid, N-hydroxyurea, and oxazoline analogues of SAHA.

PubMed

Hanessian, Stephen; Vinci, Valerio; Auzzas, Luciana; Marzi, Mauro; Giannini, Giuseppe

2006-09-15

Analogues of suberoylanilide hydroxamic acid (SAHA) were prepared by replacing the Zn-binding group with squaric acid, N-hydroxyurea, and 4-hydroxymethyl oxazoline units, also varying the length of the aliphatic chain. No inhibitory activity on HDAC was observed below 1.0 microM and no cytotoxic activity on different tumor cell lines was seen below 20.0 microM.

A Case of Recurrent Anaplastic Meningioma of the Skull Base with Radiologic Response to Hydroxyurea

PubMed Central

Gurberg, Joshua; Bouganim, Nathaniel; Shenouda, George; Zeitouni, Anthony

2014-01-01

Anaplastic meningiomas are rare and aggressive tumors with a high propensity for local recurrence. Surgical resection and postoperative radiotherapy are the standard of care for primary disease and local recurrences. Refractory disease is managed with chemotherapy with limited success. A highly efficacious, well-tolerated chemotherapeutic agent has yet to be found for this disease entity. Hydroxyurea is currently receiving renewed attention because of its efficacy in inducing apoptosis of meningioma cells in vitro and its favorable side-effect profile. Thus far, in humans, this agent has only induced stable disease. We describe the first patient showing a near complete/partial clinical and radiological regression after 5 months of 25 mg/kg of hydroxyurea once daily, given within 1 month after stereotactic fractionated reirradiation of a previously irradiated and operated anaplastic meningioma of the skull base. Magnetic resonance imaging showed a significant and sustained response with tumor shrinkage and cavitation. PMID:25083390

Clinical and hematological response to hydroxyurea in a patient with Hb Lepore/beta-thalassemia.

PubMed

Rigano, P; Manfré, L; La Galla, R; Renda, D; Renda, M C; Calabrese, A; Calzolari, R; Maggio, A

1997-05-01

The possibility of increasing Hb F in vivo using drugs like 5-azacytidine, hydroxyurea, and butyrate has been established. However, in many cases this does not entail an increase in total hemoglobin. We report on a patient with Hb Lepore/beta-thalassemia being treated with hydroxyurea (30 mg/Kg/day) because of the presence of erythroid extramedullary masses with severe neurological abnormalities. During therapy the patient showed a remarkable improvement in neurological signs due to the reduction in extra-medullary masses, a significant increase in both total hemoglobin (from 5.8 to 9.7 g/dl) and Hb F (from 4.9 g/dl to 9.1 g/dl). The marked improvement in hemoglobin level in our patient with Hb Lepore/beta-thalassemia suggests gamma-globin gene activation due to the DNA structure determined by the crossover event.

Centromere replication timing determines different forms of genomic instability in Saccharomyces cerevisiae checkpoint mutants during replication stress.

PubMed

Feng, Wenyi; Bachant, Jeff; Collingwood, David; Raghuraman, M K; Brewer, Bonita J

2009-12-01

Yeast replication checkpoint mutants lose viability following transient exposure to hydroxyurea, a replication-impeding drug. In an effort to understand the basis for this lethality, we discovered that different events are responsible for inviability in checkpoint-deficient cells harboring mutations in the mec1 and rad53 genes. By monitoring genomewide replication dynamics of cells exposed to hydroxyurea, we show that cells with a checkpoint deficient allele of RAD53, rad53K227A, fail to duplicate centromeres. Following removal of the drug, however, rad53K227A cells recover substantial DNA replication, including replication through centromeres. Despite this recovery, the rad53K227A mutant fails to achieve biorientation of sister centromeres during recovery from hydroxyurea, leading to secondary activation of the spindle assembly checkpoint (SAC), aneuploidy, and lethal chromosome segregation errors. We demonstrate that cell lethality from this segregation defect could be partially remedied by reinforcing bipolar attachment. In contrast, cells with the mec1-1 sml1-1 mutations suffer from severely impaired replication resumption upon removal of hydroxyurea. mec1-1 sml1-1 cells can, however, duplicate at least some of their centromeres and achieve bipolar attachment, leading to abortive segregation and fragmentation of incompletely replicated chromosomes. Our results highlight the importance of replicating yeast centromeres early and reveal different mechanisms of cell death due to differences in replication fork progression.

Population pharmacokinetics of hydroxyurea for children and adolescents with sickle cell disease.

PubMed

Wiczling, Paweł; Liem, Robert I; Panepinto, Julie A; Garg, Uttam; Abdel-Rahman, Susan M; Kearns, Gregory L; Neville, Kathleen A

2014-09-01

The objective of this study was to develop a population pharmacokinetic (PK) model sufficient to describe hydroxyurea (HU) concentrations in serum and urine following oral drug administration in pediatric patients with sickle cell disease. Additionally, the measured hydroxyurea concentrations for particular sampling time were correlated with exposure measures (AUC) to find the most predictive relationship. Hydroxyurea concentrations were determined in 21 subjects. Using a population nonlinear mixed-effect modeling, the HU PK was best described by a one-compartment model with two elimination pathways (metabolic and renal) and a transit compartment absorption. The typical mean absorption time was 0.222 hour. The typical apparent volume of distribution was 21.8 L and the apparent systemic clearance was 6.88 L/h for an average weight patient of 30.7 kg. The 50% of the HU dose was renally excreted. Linear correlations were apparent between the plasma HU concentration at 1, 1.5, 2, 4, and 6 hours post-dose and AUC with the most significant (R(2)  = 0.71) observed at 1.5 hours. A population PK model was successful in describing HU disposition in plasma and urine. Data from the model also demonstrated that HU plasma concentrations at 1.5 hours after an oral dose of the drug were highly predictive of systemic drug exposure. © 2014, The American College of Clinical Pharmacology.

In Vitro/In Vivo Evaluation of Radiolabeled [(99m)Tc(CO)3](+)-Hydroxyurea and Fluorescein Isothiocyanate-Hydroxyurea.

PubMed

Yilmaz, Baris; Teksoz, Serap; Kilcar, Ayfer Yurt; Ucar, Eser; Ichedef, Cigdem; Medine, Emin Ilker; Ari, Kadir

2016-02-01

The aim of current study is to examine hydroxyurea (HU), which is an antineoplastic drug used for the treatment of leukemia, sickle-cell disease, HIV, psoriasis, thrombocythemia, and various neoplastic diseases in two aspects. The active ingredient hydroxyurea was obtained by purification of the capsule form drug, commercially named as HYDREA. Then, [(99m)Tc(CO)3](+)core radiolabeling with HU was performed as first aspect. Quality control studies of (99m)Tc(CO)3-HU complex were performed by thin-layer radiochromatography and high-performance liquid radiochromatography methods. The results demonstrated that the radiolabeling yield was quite high (98.43% ± 2.29%). Also, (99m)Tc(CO)3-HU complex has good stability during the 24-hour period. Biological behavior of (99m)Tc(CO)3-HU complex is evaluated by biodistribution studies on Wistar Albino rats. Fluorescein isothiocyanate (FITC) labeling of HU was performed as second aspect. Fluorometric evaluation of binding efficacy and fluorescence imaging studies on MCF7 and Hela cell lines were carried out. It was thought that the knowledge achieved in this study would contribute to using (99m)Tc(CO)3-HU complex as an imaging agent, which inhibits the DNA synthesis selectively, by inhibiting ribonucleotide reductase enzyme. It was observed that FITC-HU has noteworthy incorporation on both cell lines.

Ruxolitinib is effective and safe in Japanese patients with hydroxyurea-resistant or hydroxyurea-intolerant polycythemia vera with splenomegaly.

PubMed

Kirito, Keita; Suzuki, Kenshi; Miyamura, Koichi; Takeuchi, Masahiro; Handa, Hiroshi; Okamoto, Shinichiro; Gadbaw, Brian; Yamauchi, Kyosuke; Amagasaki, Taro; Ito, Kazuo; Hino, Masayuki

2018-02-01

Ruxolitinib, a potent JAK1/JAK2 inhibitor, was found to be superior to the best available therapy (BAT) in controlling hematocrit, reducing splenomegaly, and improving symptoms in the phase 3 RESPONSE study of patients with polycythemia vera with splenomegaly who experienced an inadequate response to or adverse effects from hydroxyurea. We report findings from a subgroup analysis of Japanese patients in RESPONSE (n = 18). The composite response rate (hematocrit control and spleen response) was higher in patients receiving ruxolitinib (50.0%) than in those receiving BAT (8.3%). A total of 50.0% of patients randomized to ruxolitinib achieved a spleen response vs 8.3% of those receiving BAT; 100 and 33.3% of patients in the respective groups achieved hematocrit control, with mean hematocrit in ruxolitinib-treated patients remaining stable at < 45% throughout the study. Similarly, a higher proportion of ruxolitinib-treated patients achieved complete hematologic remission (33.3 vs 16.7%). Ruxolitinib also led to rapid improvements in pruritus. All responses with ruxolitinib were durable to week 80, and its safety profile was consistent with that in the overall study. These findings suggest that ruxolitinib is an effective and well-tolerated treatment option for Japanese patients with polycythemia vera with an inadequate response to or adverse effects from hydroxyurea.

Health-related quality of life and adherence to hydroxyurea in adolescents and young adults with sickle cell disease.

PubMed

Badawy, Sherif M; Thompson, Alexis A; Lai, Jin-Shei; Penedo, Frank J; Rychlik, Karen; Liem, Robert I

2017-06-01

Complications related to sickle cell disease (SCD) result in significant declines in health-related quality of life (HRQOL). While hydroxyurea reduces SCD complications, adherence remains suboptimal. The study's objectives were to assess the feasibility of Internet-based electronic assessment of HRQOL in SCD clinic and to examine the relationship between HRQOL and hydroxyurea adherence in adolescents and young adults (AYAs) with SCD. A cross-sectional survey was administered on tablets to 34 AYAs (12-22 years old) in a SCD clinic from January through December 2015. Study measures included Patient Reported Outcomes Measurement Information System (PROMIS ® ) computerized adaptive testing and ©Modified Morisky Adherence Scale 8-items (©MMAS-8). Participants (59% male, 91% Black) had median age of 13.5 (range 12-18) years. Ninety-one percent completed PROMIS® measures electronically in the clinic, meeting our feasibility criterion of ≥85% completion rate. ©MMAS-8 scores positively correlated with fetal hemoglobin (HbF) (r s = 0.34, P = 0.04) and mean corpuscular volume (MCV) (r s = 0.42, P = 0.01) and inversely correlated with fatigue (r s = -0.45, P = 0.01), depression (r s = -0.3, P = 0.08), and social isolation (r s = -0.78, P = 0.02). Low ©MMAS-8 scores, indicating poor adherence, were associated with worse fatigue (P = 0.001) and trended toward significance for pain (P = 0.07) and depression (P = 0.06). Homozygous hemoglobin S disease patients with low HbF (<16%) had worse social isolation (P = 0.04) and those with low MCV (<102 fl) reported worse fatigue (P = 0.001), pain (P = 0.01), mobility (P = 0.01), and social isolation (P = 0.04). HRQOL assessment in the SCD clinic is feasible. SCD patients with low hydroxyurea adherence and/or low HbF or MCV levels had worse HRQOL scores, particularly fatigue. Future prospective studies examining the relationship between HRQOL and hydroxyurea adherence are warranted. © 2016 Wiley Periodicals, Inc.

Severe excessive daytime sleepiness induced by hydroxyurea.

PubMed

Revol, Bruno; Joyeux-Faure, Marie; Albahary, Marie-Victoire; Gressin, Remy; Mallaret, Michel; Pepin, Jean-Louis; Launois, Sandrine H

2017-06-01

Excessive daytime sleepiness (EDS) has been reported with many drugs, either as an extension of a hypnotic effect (e.g. central nervous system depressants) or as an idiosyncratic response of the patient. Here, we report unexpected and severe subjective and objective EDS induced by hydroxyurea therapy, with a favorable outcome after withdrawal. Clinical history, sleep log, polysomnography, and multiple sleep latency tests confirming the absence of other EDS causes are presented. © 2016 Société Française de Pharmacologie et de Thérapeutique.

P11.10 Role of hydroxyurea as an adjuvant treatment after gamma knife radiosurgery for atypical (WHO grade II) meningiomas

PubMed Central

Abdel Karim, K.; El Shehaby, A.; Emad, R.; Reda, W.; El Mahdy, M.; Ghali, R.; Nabeel, A.

2016-01-01

Abstract Objective: The use of gamma knife radiosurgery in the treatment of atypical (WHO grade II) meningiomas has been reported in the past with highly variable degrees of success. The use of hydroxyurea as a radiation sensitizer as well as salvage chemotherapy in cancer patients is well established and was also used for treatment of recurrent and malignant meningiomas. In this study we investigated the effect of hydroxyurea administration after gamma knife radiosurgery for atypical (grade II) meningiomas on local tumor control and patient survival. Patients and methods: Between November 2008 and April 2014, thirty-five patients with pathologically proven atypical meningiomas were treated by gamma knife radiosurgery. We excluded patients who had received previous external beam radiotherapy. Twenty-three patients were given hydroxyurea after gamma knife treatment. The rest of the patients refused to take the treatment or were incompliant (were not included in the study). Of these 23, nineteen patients harboring 20 tumors were available for radiological and clinical follow up for a minimum of 2 years. Four patients were lost from follow up. Twenty tumors underwent 26 gamma knife procedures. Five tumors underwent staged treatment. The tumor volume was 0.6–38.3 cc (median 12.7 cc). The prescription dose/session ranged from 10 to 16 Gy (mean 14 Gy). The patients received a course of hydroxyurea (1000 mg/day) for one year after gamma knife treatment. The mean follow up period was 43 months (14–76 months). Results: Tumor control was achieved in 18 out of 20 tumors where 15 tumors shrank and 3 tumors remained stable with a tumor control rate of 90%. Tumor progression occurred in 2 patients (at 14 and 15 months). Transient edema was observed with 6 tumors which was temporary, and no G3 or G4 myelosuppression were recorded. Two patients died from progression of other tumors not included in the study after 3 and 6 years. Distant tumor progression (in another intracranial location or outside the radiation field) was observed in 5 patients. In 3 patients new tumors developed at the edge of previous craniotomy, in one patient tumor progression occurred after receiving radiosurgery alone for another lesion after the end of adjuvant treatment and in one patient progression occurred in an untreated tumor that was under observation. The actuarial progression free survival and overall survival at 3 years were 89.5% and 94% respectively. Conclusion: Preliminary results suggest good tumor control and shrinkage of atypical (grade II) meningiomas treated with Gamma Knife radiosurgery followed by one year of adjuvant hydroxyurea. Further larger randomized and double-arm studies are required to confirm the potential role of hydroxyurea in those tumors.

Essential thrombocythaemia in two dogs.

PubMed

Favier, R P; van Leeuwen, M; Teske, E

2004-06-01

In this report two dogs with essential thrombocythaemia (ET) are described. Both dogs were presented more or less at the same time with a combination of reduced exercise tolerance and pale mucous membranes without any report of blood loss. Moderate-to-severe, Coomb's-negative anaemia and thrombocytosis (> 1249 x 10'/l) were present. In addition, the peripheral blood smear revealed the presence of basophilia and large numbers of abnormally shaped megakaryocytes in the bone marrow of both dogs. Treatment with vincristine (0.7 mg/m2 once intravenously) and hydroxyurea (500 mg/m2 p.o. per day) was started. Because of insufficient response to treatment after 3 weeks, the dosage of hydroxyurea was increased in both dogs to 2000 mg/m2 p.o. per day. The dogs deteriorated further, however, and were euthanized at 6 weeks after the start of treatment. Blood examination revealed pancytopenia in both dogs, most likely due to the myelosuppressive effects of high-dose hydroxyurea. A survey of veterinary literature on ET is presented, including a comparison of ET in humans.

Dissociative electron attachment to the radiosensitizing chemotherapeutic agent hydroxyurea

NASA Astrophysics Data System (ADS)

Huber, S. E.; Śmiałek, M. A.; Tanzer, K.; Denifl, S.

2016-06-01

Dissociative electron attachment to hydroxyurea was studied in the gas phase for electron energies ranging from zero to 9 eV in order to probe its radiosensitizing capabilities. The experiments were carried out using a hemispherical electron monochromator coupled with a quadrupole mass spectrometer. Diversified fragmentation of hydroxyurea was observed upon low energy electron attachment and here we highlight the major dissociation channels. Moreover, thermodynamic thresholds for various fragmentation reactions are reported to support the discussion of the experimental findings. The dominant dissociation channel, which was observed over a broad range of energies, is associated with formation of NCO-, water, and the amidogen (NH2) radical. The second and third most dominant dissociation channels are associated with formation of NCNH- and NHCONH2-, respectively, which are both directly related to formation of the highly reactive hydroxyl radical. Other ions observed with significant abundance in the mass spectra were NH2-/O-, OH-, CN-, HNOH-, NCONH2-, and ONHCONH2-.

NEK8 regulates DNA damage-induced RAD51 foci formation and replication fork protection

PubMed Central

Abeyta, Antonio; Castella, Maria; Jacquemont, Celine; Taniguchi, Toshiyasu

2017-01-01

ABSTRACT Proteins essential for homologous recombination play a pivotal role in the repair of DNA double strand breaks, DNA inter-strand crosslinks and replication fork stability. Defects in homologous recombination also play a critical role in the development of cancer and the sensitivity of these cancers to chemotherapy. RAD51, an essential factor for homologous recombination and replication fork protection, accumulates and forms immunocytochemically detectable nuclear foci at sites of DNA damage. To identify kinases that may regulate RAD51 localization to sites of DNA damage, we performed a human kinome siRNA library screen, using DNA damage-induced RAD51 foci formation as readout. We found that NEK8, a NIMA family kinase member, is required for efficient DNA damage-induced RAD51 foci formation. Interestingly, knockout of Nek8 in murine embryonic fibroblasts led to cellular sensitivity to the replication inhibitor, hydroxyurea, and inhibition of the ATR kinase. Furthermore, NEK8 was required for proper replication fork protection following replication stall with hydroxyurea. Loading of RAD51 to chromatin was decreased in NEK8-depleted cells and Nek8-knockout cells. Single-molecule DNA fiber analyses revealed that nascent DNA tracts were degraded in the absence of NEK8 following treatment with hydroxyurea. Consistent with this, Nek8-knockout cells showed increased chromosome breaks following treatment with hydroxyurea. Thus, NEK8 plays a critical role in replication fork stability through its regulation of the DNA repair and replication fork protection protein RAD51. PMID:27892797

NEK8 regulates DNA damage-induced RAD51 foci formation and replication fork protection.

PubMed

Abeyta, Antonio; Castella, Maria; Jacquemont, Celine; Taniguchi, Toshiyasu

2017-02-16

Proteins essential for homologous recombination play a pivotal role in the repair of DNA double strand breaks, DNA inter-strand crosslinks and replication fork stability. Defects in homologous recombination also play a critical role in the development of cancer and the sensitivity of these cancers to chemotherapy. RAD51, an essential factor for homologous recombination and replication fork protection, accumulates and forms immunocytochemically detectable nuclear foci at sites of DNA damage. To identify kinases that may regulate RAD51 localization to sites of DNA damage, we performed a human kinome siRNA library screen, using DNA damage-induced RAD51 foci formation as readout. We found that NEK8, a NIMA family kinase member, is required for efficient DNA damage-induced RAD51 foci formation. Interestingly, knockout of Nek8 in murine embryonic fibroblasts led to cellular sensitivity to the replication inhibitor, hydroxyurea, and inhibition of the ATR kinase. Furthermore, NEK8 was required for proper replication fork protection following replication stall with hydroxyurea. Loading of RAD51 to chromatin was decreased in NEK8-depleted cells and Nek8-knockout cells. Single-molecule DNA fiber analyses revealed that nascent DNA tracts were degraded in the absence of NEK8 following treatment with hydroxyurea. Consistent with this, Nek8-knockout cells showed increased chromosome breaks following treatment with hydroxyurea. Thus, NEK8 plays a critical role in replication fork stability through its regulation of the DNA repair and replication fork protection protein RAD51.

Hydroxyurea derivatives of irofulven with improved antitumor efficacy.

PubMed

Staake, Michael D; Kashinatham, Alisala; McMorris, Trevor C; Estes, Leita A; Kelner, Michael J

2016-04-01

Irofulven is a semi-synthetic derivative of Illudin S, a toxic sesquiterpene isolated from the mushroom Omphalotus illudens. Irofulven has displayed significant antitumor activity in various clinical trials but displayed a limited therapeutic index. A new derivative of irofulven was prepared by reacting hydroxyurea with irofulven under acidic conditions. Acetylation of this new compound with acetic anhydride produced a second derivative. Both of these new derivatives displayed significant antitumor activity in vitro and in vivo comparable to or exceeding that of irofulven. Copyright © 2016 Elsevier Ltd. All rights reserved.

Phase II study of imatinib mesylate and hydroxyurea for recurrent grade III malignant gliomas.

PubMed

Desjardins, Annick; Quinn, Jennifer A; Vredenburgh, James J; Sathornsumetee, Sith; Friedman, Allan H; Herndon, James E; McLendon, Roger E; Provenzale, James M; Rich, Jeremy N; Sampson, John H; Gururangan, Sridharan; Dowell, Jeannette M; Salvado, August; Friedman, Henry S; Reardon, David A

2007-05-01

Recent reports demonstrate the activity of imatinib mesylate, an ATP-mimetic, tyrosine kinase inhibitor, plus hydroxyurea, a ribonucleotide reductase inhibitor, in patients with recurrent glioblastoma multiforme. We performed the current phase 2 study to evaluate this regimen among patients with recurrent WHO grade III malignant glioma (MG). Patients with grade III MG at any recurrence, received imatinib mesylate plus hydroxyurea (500 mg twice a day) orally on a continuous, daily schedule. The imatinib mesylate dose was 500 mg twice a day for patients on enzyme inducing anti-epileptic drugs (EIAEDs) and 400 mg once a day for those not on EIAEDs. Clinical assessments were performed monthly and radiographic assessments were obtained at least every 2 months. The primary endpoint was 6-month progression-free survival (PFS) rate. Thirty-nine patients were enrolled. All patients had progressive disease after prior radiotherapy and at least temozolomide-based chemotherapy. The median number of episodes of prior progression was 2 (range, 1-7) and the median number of prior treatment regimens was 3 (range, 1-8). With a median follow-up of 82.9 weeks, 24% of patients were progression-free at 6 months. The radiographic response rate was 10%, while 33% achieved stable disease. Among patients who achieved at least stable disease at first evaluation, the 6-month and 12-month PFS rates were 53% and 29%, respectively. The most common grade 3 or greater toxicities were hematologic and complicated less than 4% of administered courses. Imatinib mesylate plus hydroxyurea, is well tolerated and associated with anti-tumor activity in some patients with recurrent grade 3 MG.

Role of XmnIgG Polymorphism in Hydroxyurea Treatment and Fetal Hemoglobin Level at Isfahanian Intermediate β-Thalassemia Patients.

PubMed

Motovali-Bashi, Majid; Ghasemi, Tayyebeh

2015-01-01

β-thalassemia is the most common monogenic disorder in human. The (C-->T) polymorphism at -158 upstream region of the γG-globin gene and pharmacological factors such as hydroxyurea have been reported to influence γ-globin gene expression and the severity of clinical symptoms of β-thalassemia. In the present study, 51 β-thalassemia intermediate patients were studied. Xmn1γG polymorphism genotype was determined using Tetra-Primer ARMS-PCR technique. Hemoglobin (Hb) and fetal hemoglobin (HbF) levels were determined by gel electrophoresis. Of 51 patients, 35 (68.6%) patients were heterozygous (CT) and 16 (31.4%) patients were homozygous (CC). Of 30 patients under treatment by hydroxyurea, 20 (66.7%) patients were heterozygous (CT) and 10 (33.3%) patients were homozygous (CC). Our results demonstrated that in the heterozygous (CT) genotype, the Hb (9.58 ± 1.25 gm/dl) and HbF (89.30 ± 21.87) levels were significantly higher in comparison with homozygous (CC) genotype (7.94 ± 1.34 gm/dl and 70.32 ± 40.56, respectively). Furthermore, we observed that after drug usage, the Hb and HbF levels in patients with heterozygous (CT) genotype (0.7 ± 1.26 gm/dl and 5.95 ± 14.8, respectively) raised more in comparison with homozygous (CC) genotype (0.26 ± 1.43 gm/dl and 0.8 ± 1.31, respectively). Hb and HbF levels in the patients carrying T allele are increased significantly, and they also response to hydroxyurea treatment.

Dissociative electron attachment to the radiosensitizing chemotherapeutic agent hydroxyurea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huber, S. E.; Tanzer, K.; Denifl, S.

Dissociative electron attachment to hydroxyurea was studied in the gas phase for electron energies ranging from zero to 9 eV in order to probe its radiosensitizing capabilities. The experiments were carried out using a hemispherical electron monochromator coupled with a quadrupole mass spectrometer. Diversified fragmentation of hydroxyurea was observed upon low energy electron attachment and here we highlight the major dissociation channels. Moreover, thermodynamic thresholds for various fragmentation reactions are reported to support the discussion of the experimental findings. The dominant dissociation channel, which was observed over a broad range of energies, is associated with formation of NCO{sup −}, water,more » and the amidogen (NH{sub 2}) radical. The second and third most dominant dissociation channels are associated with formation of NCNH{sup −} and NHCONH{sub 2}{sup −}, respectively, which are both directly related to formation of the highly reactive hydroxyl radical. Other ions observed with significant abundance in the mass spectra were NH{sub 2}{sup −}/O{sup −}, OH{sup −}, CN{sup −}, HNOH{sup −}, NCONH{sub 2}{sup −}, and ONHCONH{sub 2}{sup −}.« less

Sickle cell disease caused by Hb S/Québec-CHORI: treatment with hydroxyurea and response.

PubMed

Tubman, Venée N; Bennett, Carolyn M; Luo, Hong-yuan; Chui, David H K; Heeney, Matthew M

2007-08-01

Sickle hemoglobin (Hb S;betaGlu 6 Val) is due to an A>T transversion in codon 6 of the beta-globin gene. Other variant hemoglobins mimic Hb A, S, or C on newborn screening and clinical laboratory diagnostic tools, thus making their correct identification potentially difficult. Sickling disorders can result in individuals who are compound heterozygous for beta-globin mutations (e.g., Hb SC, HbSO(Arab)). The authors report a second case of HbS/Québec-CHORI, a severe compound heterozygous sickling disorder and their experience managing this patient with hydroxyurea.

ARQ 092, an orally-available, selective AKT inhibitor, attenuates neutrophil-platelet interactions in sickle cell disease

PubMed Central

Kim, Kyungho; Li, Jing; Barazia, Andrew; Tseng, Alan; Youn, Seock-Won; Abbadessa, Giovanni; Yu, Yi; Schwartz, Brian; Andrews, Robert K.; Gordeuk, Victor R.; Cho, Jaehyung

2017-01-01

Previous studies identified the Ser/Thr protein kinase, AKT, as a therapeutic target in thrombo-inflammatory diseases. Here we report that specific inhibition of AKT with ARQ 092, an orally-available AKT inhibitor currently in phase Ib clinical trials as an anti-cancer drug, attenuates the adhesive function of neutrophils and platelets from sickle cell disease patients in vitro and cell-cell interactions in a mouse model of sickle cell disease. Studies using neutrophils and platelets isolated from sickle cell disease patients revealed that treatment with 50–500 nM ARQ 092 significantly blocks αMβ2 integrin function in neutrophils and reduces P-selectin exposure and glycoprotein Ib/IX/V-mediated agglutination in platelets. Treatment of isolated platelets and neutrophils with ARQ 092 inhibited heterotypic cell-cell aggregation under shear conditions. Intravital microscopic studies demonstrated that short-term oral administration of ARQ 092 or hydroxyurea, a major therapy for sickle cell disease, diminishes heterotypic cell-cell interactions in venules of sickle cell disease mice challenged with tumor necrosis factor-α. Co-administration of hydroxyurea and ARQ 092 further reduced the adhesive function of neutrophils in venules and neutrophil transmigration into alveoli, inhibited expression of E-selectin and intercellular adhesion molecule-1 in cremaster vessels, and improved survival in these mice. Ex vivo studies in sickle cell disease mice suggested that co-administration of hydroxyurea and ARQ 092 efficiently blocks neutrophil and platelet activation and that the beneficial effect of hydroxyurea results from nitric oxide production. Our results provide important evidence that ARQ 092 could be a novel drug for the prevention and treatment of acute vaso-occlusive complications in patients with sickle cell disease. PMID:27758820

Survival among children and adults with sickle cell disease in Belgium: Benefit from hydroxyurea treatment.

PubMed

Lê, Phu Quoc; Gulbis, Béatrice; Dedeken, Laurence; Dupont, Sophie; Vanderfaeillie, Anna; Heijmans, Catherine; Huybrechts, Sophie; Devalck, Christine; Efira, André; Dresse, Marie-Françoise; Rozen, Laurence; Benghiat, Fleur Samantha; Ferster, Alina

2015-11-01

To evaluate the survival of patients with sickle cell disease (SCD) recorded in the Belgian SCD Registry and to assess the impact of disease-modifying treatments (DMT). The Registry created in 2008 included patients of eight centers. All available data in 2008 were retrospectively encoded in the database. After 2008 and until 2012, all data were recorded prospectively for already registered patients as well as newly diagnosed subjects. Data were registered from neonatal screening or from diagnosis (first contact) until last follow-up or death. Data included diagnosis, demography, and outcome data. We collected data from 469 patients over a 5,110 patient years (PY) follow-up period. The global mortality rate was low (0.25/100 PY), although 13 patients died (2.8%) and was similar between children, adolescents (10-18 years), and young adults (P = 0.76). Out of the cohort, 185 patients received hydroxyurea at last follow-up (median duration of treatment: 10.3 years), 90 underwent hematopoietic stem cell transplantation (HSCT), 24 were chronically transfused, and 170 had never had any DMT. Hydroxyurea showed significant benefit on patients outcome as reflected by a lower mortality rate compared to transplanted individuals or people without DMT (0.14, 0.36, and 0.38 per 100 PY, respectively) and by higher Kaplan-Meier estimates of 15 year survival (99.4%) compared to HSCT (93.8%; P = 0.01) or no DMT groups (95.4%; P = 0.04). SCD mortality in Belgium is low with no increase observed in young adults. Patients treated with hydroxyurea demonstrate a significant benefit in survival when compared to those without DMT or transplanted. © 2015 Wiley Periodicals, Inc.

Polycythemia Vera Management and Challenges in the Community Health Setting

PubMed Central

Gerds, Aaron T.; Dao, Kim-Hien

2017-01-01

Patients with polycythemia vera (PV) experience shortened survival, increased risk of thromboembolic and hemorrhagic events, and burdensome symptoms. For all patients with PV, treatment with aspirin and hematocrit control with phlebotomy are recommended. In addition, patients with high-risk status or poor hematocrit control benefit from cytoreductive therapy with hydroxyurea, although approximately 1 in 4 patients develops resistance or intolerance. For patients who are resistant to or intolerant of hydroxyurea, studies have shown that ruxolitinib, a Janus kinase 1/2 inhibitor, provides hematocrit control, reduces spleen size, normalizes blood counts, and improves PV-related symptoms. For many patients, PV is managed in a community health setting, and it is important that community hematologists, oncologists, and internists are familiar with the contemporary management of PV to improve patient outcomes, including management for patients who present with unique health-care needs. This review provides an overview of current treatment options for patients with PV and discusses challenging circumstances encountered by community providers in the management of PV, including symptom assessment, identification of hydroxyurea resistance/intolerance, pregnancy, elective surgeries, concomitant immunosuppressants, and managing patients in areas with limited access to specialized hematologic care. PMID:28095380

Catalase and NO CATALASE ACTIVITY1 Promote Autophagy-Dependent Cell Death in Arabidopsis[C][W][OPEN

PubMed Central

Hackenberg, Thomas; Juul, Trine; Auzina, Aija; Gwiżdż, Sonia; Małolepszy, Anna; Van Der Kelen, Katrien; Dam, Svend; Bressendorff, Simon; Lorentzen, Andrea; Roepstorff, Peter; Lehmann Nielsen, Kåre; Jørgensen, Jan-Elo; Hofius, Daniel; Breusegem, Frank Van; Petersen, Morten; Andersen, Stig Uggerhøj

2013-01-01

Programmed cell death often depends on generation of reactive oxygen species, which can be detoxified by antioxidative enzymes, including catalases. We previously isolated catalase-deficient mutants (cat2) in a screen for resistance to hydroxyurea-induced cell death. Here, we identify an Arabidopsis thaliana hydroxyurea-resistant autophagy mutant, atg2, which also shows reduced sensitivity to cell death triggered by the bacterial effector avrRpm1. To test if catalase deficiency likewise affected both hydroxyurea and avrRpm1 sensitivity, we selected mutants with extremely low catalase activities and showed that they carried mutations in a gene that we named NO CATALASE ACTIVITY1 (NCA1). nca1 mutants showed severely reduced activities of all three catalase isoforms in Arabidopsis, and loss of NCA1 function led to strong suppression of RPM1-triggered cell death. Basal and starvation-induced autophagy appeared normal in the nca1 and cat2 mutants. By contrast, autophagic degradation induced by avrRpm1 challenge was compromised, indicating that catalase acted upstream of immunity-triggered autophagy. The direct interaction of catalase with reactive oxygen species could allow catalase to act as a molecular link between reactive oxygen species and the promotion of autophagy-dependent cell death. PMID:24285797

Amphiphilic lipid derivatives of 3'-hydroxyurea-deoxythymidine: preparation, properties, molecular self-assembly, simulation and in vitro anticancer activity.

PubMed

Li, Miao; Qi, Shuo; Jin, Yiguang; Yao, Weishang; Zhang, Sa; Zhao, Jingyu

2014-11-01

Lipid derivatives of nucleoside analogs and their nanoassemblies have become the research hotspot due to their unique function in cancer therapy. Six lipid derivatives of 3'-hydroxyurea-deoxythymidine were prepared with zidovudine as the raw material. The 5'-substituted lipid chains in the derivatives were from the various fatty acids including octanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid and octadecanoic acid corresponding to the derivatives OHT, DHT, DDHT, TDHT, HDHT and ODHT. The amphiphilic derivatives formed Langmuir monolayers at the air/water interface with different surface pressure-molecular area isotherms depending on the length of lipid chains. The nanoassemblies of OHT, DHT, DDHT, TDHT and HDHT and the nanoscale precipitates of ODHT were obtained after we injected their tetrahydrofuran solutions doped with hydrophilic long chained polymers into water. Electron microscopy showed that the morphology of nanoassemblies may be vesicles or nanotubes depending on the length of lipid chains. The shorter the lipid chains were, the softer the nanoassemblies. Computer simulation supported the experimental results. The nanoassemblies and the nanoscale precipitates showed much higher anticancer effects on SW620 cells than the parent drug hydroxyurea. The nanostructures of the derivatives are promising anticancer nanomedicines. Copyright © 2014 Elsevier B.V. All rights reserved.

Cid1, a Fission Yeast Protein Required for S-M Checkpoint Control when DNA Polymerase δ or ɛ Is Inactivated

PubMed Central

Wang, Shao-Win; Toda, Takashi; MacCallum, Robert; Harris, Adrian L.; Norbury, Chris

2000-01-01

The S-M checkpoint is an intracellular signaling pathway that ensures that mitosis is not initiated in cells undergoing DNA replication. We identified cid1, a novel fission yeast gene, through its ability when overexpressed to confer specific resistance to a combination of hydroxyurea, which inhibits DNA replication, and caffeine, which overrides the S-M checkpoint. Cid1 overexpression also partially suppressed the hydroxyurea sensitivity characteristic of DNA polymerase δ mutants and mutants defective in the “checkpoint Rad” pathway. Cid1 is a member of a family of putative nucleotidyltransferases including budding yeast Trf4 and Trf5, and mutation of amino acid residues predicted to be essential for this activity resulted in loss of Cid1 function in vivo. Two additional Cid1-like proteins play similar but nonredundant checkpoint-signaling roles in fission yeast. Cells lacking Cid1 were found to be viable but specifically sensitive to the combination of hydroxyurea and caffeine and to be S-M checkpoint defective in the absence of Cds1. Genetic data suggest that Cid1 acts in association with Crb2/Rhp9 and through the checkpoint-signaling kinase Chk1 to inhibit unscheduled mitosis specifically when DNA polymerase δ or ɛ is inhibited. PMID:10757807

Can hydroxyurea serve as a free radical scavenger and reduce iron overload in β-thalassemia patients?

PubMed

Italia, Khushnooma; Chandrakala, S; Ghosh, Kanjaksha; Colah, Roshan

2016-09-01

In this study, we hypothesize that hydroxyurea could provide an additional benefit as a free radical scavenger and/or iron chelator in β-thalassemia patients with iron overload. Twenty-one β-thalassemia intermedia patients who presented between 3 and 17 years but later required regular blood transfusions were enrolled for hydroxyurea therapy for a year. Fourteen patients responded to the therapy with hemoglobin levels maintained above 7.5 g/dl without transfusions. Hydroxyurea was discontinued after 6 months in seven patients who did not respond to the therapy and had to be continued on regular blood transfusions. We observed a statistically significant decrease in serum ferritin levels from 4194 ± 4850 ng/ml to 2129 ± 2380 ng/ml among the responders and from 2955 ± 2909 ng/ml to 2040 ± 2432 ng/ml among the non-responders and statistically significant decrease in labile iron pool from 18678.7 ± 10067.4 mean fluorescence intensity (MFI) to 14888.5 ± 5284.0 MFI among responders and from 17986.3 ± 9079.8 MFI to 15634.8 ± 8976.9 MFI among the non-responders after therapy. Phosphatidylserine externalization also showed a statistically significant decrease from 44.2 ± 22.2 MFI to 16.6 ± 6.7 MFI among the responders and from 46.9 ± 33.1 MFI to 39.8 ± 7.4 MFI among the non-responders along with a statistically significant decrease in the levels of reactive oxygen species from 72.8 ± 35.5 MFI to 29.0 ± 8.3 MFI among the responders and from 80.9 ± 41.4 MFI to 40.5 ± 15.8 MFI among the non-responders after therapy. A statistically significant increase in reduced glutathione levels was also observed from 430.8 ± 201.1 MFI to 715.5 ± 292.4 MFI among the responders and from 359.6 ± 165.6 MFI to 450.3 ± 279.5 MFI among the non-responders after therapy. This suggests the possible additional role of hydroxyurea as a free radical scavenger and/or iron chelator but requires a larger study for substantiation.

L-glutamine for sickle cell anemia: more questions than answers.

PubMed

Quinn, Charles T

2018-06-12

In 2017, the Food and Drug Administration (FDA) approved two medications for sickle cell anemia (SCA): hydroxyurea for children (≥2 years of age) and L-glutamine for children and adults (≥5 years). The approval of hydroxyurea for children was long overdue, having been authorized by the FDA for adults in 1998 and by the European Medicines Agency for adults and children in 2007, but the approval of L-glutamine was a surprise to many in the field. There are few published studies of L-glutamine as a treatment for SCA, so all can be reviewed in this brief manuscript. Accordingly, there are many unanswered questions about L-glutamine and its role in current therapy for SCA. Copyright © 2018 American Society of Hematology.

Secondary benefit of maintaining normal transcranial Doppler velocities when using hydroxyurea for prevention of severe sickle cell anemia.

PubMed

Ghafuri, Djamila Labib; Chaturvedi, Shruti; Rodeghier, Mark; Stimpson, Sarah-Jo; McClain, Brandi; Byrd, Jeannie; DeBaun, Michael R

2017-07-01

In a retrospective cohort study, we tested the hypothesis that when prescribing hydroxyurea (HU) to children with sickle cell anemia (SCA) to prevent vaso-occlusive events, there will be a secondary benefit of maintaining low transcranial Doppler (TCD) velocity, measured by imaging technique (TCDi). HU was prescribed for 90.9% (110 of 120) of children with SCA ≥5 years of age and followed for a median of 4.4 years, with 70% (n = 77) receiving at least one TCDi evaluation after starting HU. No child prescribed HU had a conditional or abnormal TCDi measurement. HU initiation for disease severity prevention decreases the prevalence of abnormal TCDi velocities. © 2016 Wiley Periodicals, Inc.

Comparing abstract numerical and visual depictions of risk in survey of parental assessment of risk in sickle cell hydroxyurea treatment.

PubMed

Patterson, Chavis A; Barakat, Lamia P; Henderson, Phyllis K; Nall, Faith; Westin, Anna; Dampier, Carlton D; Hsu, Lewis L

2011-01-01

Communicating risk is an important activity in medical decision-making; yet, numeracy is not a universal skill among the American public. We examined the hypothesis that numerical risk information about the use of hydroxyurea for children with sickle cell disease would elicit different risk assessment responses when visual depictions were used instead of abstract numbers and depending on the disease severity. Parents of 81 children with sickle cell disease participated in a survey in which hydroxyurea was first described as carrying a certain chance of risk for both birth defects and cancer. Then, the parents indicated the highest risk at which they would hypothetically consent to the treatment to help their child. Risk presentations were repeated with abstract numerical, pie graph, and 1000 people histogram formats. The χ analyses comparing high-risk to low-risk assessment across presentation formats showed high consistency between visual depictions but low consistency of abstract numerical with visual depictions. The parents of children with SC and other less severe types of SCD were less willing to accept higher risk than those with SS when the data were presented numerically. Given earlier concerns about poor "numeracy" in the US population, visual depictions of risk could be an effective tool for routine communication in health education and medical decision-making.

[Is therapeutic progress in the management of sickle cell disease applicable in sub-Saharan Africa?].

PubMed

De Montalembert, M; Tshilolo, L

2007-12-01

The life expectancy of patients with sickle cell disease has improved in the United States and Europe thanks to the use of penicillin prophylaxis, appropriate immunizations, neonatal screening, implementation of a quality transfusional policy, hydroxyurea therapy, detection and treatment of cerebral vasculopathy, recognition of situations that can benefit from allogenic marrow transplantation, and improvements in bone marrow transplantation techniques. The cost of almost all these techniques is far beyond the means of health care systems in Africa where they cannot be used. However at least three, i.e., penicillin, vaccines, and hydroxyurea, could be easily accessible in the framework of defined therapeutic strategies. If daily penicillin and pneumococcal vaccine Pneumo 23 are required, it would likely be necessary to select a conjugated vaccine other than Prevenar that does not provide protection against all strains present in Africa. Neonatal screening is still a rare procedure in sub-Saharan countries. Periodic transfusion is steadily improving but exchange transfusion programs aimed in particular at preventing neurological complications are still unfeasible. Indications for hydroxyurea therapy in Africa are more common due to the lack of access to chronic transfusion and must be based on consensus decision. Use of bone marrow transplantation, i.e., the only currently available curative treatment, is still possible only in northern hemisphere countries where it is still restricted to children with severe forms and an HLA-compatible family donor.

Toxicity of hydroxyurea in rats and dogs.

PubMed

Morton, Daniel; Reed, Lori; Huang, Wenhu; Marcek, John M; Austin-LaFrance, Robert; Northcott, Carrie A; Schelling, Scott H; Enerson, Bradley E; Tomlinson, Lindsay

2015-06-01

The toxicity of hydroxyurea, a treatment for specific neoplasms, sickle-cell disease, polycythemia, and thrombocytosis that kills cells in mitosis, was assessed in repeat-dose, oral gavage studies in rats and dogs and a cardiovascular study in telemetered dogs. Hydroxyurea produced hematopoietic, lymphoid, cardiovascular, and gastrointestinal toxicity with steep dose response curves. In rats dosed for 10 days, 50 mg/kg/day was tolerated; 500 mg/kg/day produced decreased body weight gain; decreased circulating leukocytes, erythrocytes, and platelets; decreased cellularity of thymus, lymph nodes, and bone marrow; and epithelial degeneration and/or dysplasia of the stomach and small intestine; 1,500 mg/kg/day resulted in deaths on day 5. In dogs, a single dose at ≥ 250 mg/kg caused prostration leading to unscheduled euthanasia. Dogs administered 50 mg/kg/day for 1 month had decreased circulating leukocytes, erythrocytes, and platelets; increased bone marrow cellularity with decreased maturing granulocytes; increased creatinine kinase activity; and increased iron pigment in bone marrow and hepatic sinusoidal cells. In telemetered dogs, doses ≥ 15 mg/kg decreased systolic blood pressure (BP); 50 mg/kg increased diastolic BP, heart rate, and change in blood pressure over time (+dP/dt), and decreased QT and PR intervals and maximum left ventricular systolic and end diastolic pressures with measures returning to control levels within 24 hr. © 2014 by The Author(s).

Exploiting the spatial locality of electron correlation within the parametric two-electron reduced-density-matrix method

NASA Astrophysics Data System (ADS)

DePrince, A. Eugene; Mazziotti, David A.

2010-01-01

The parametric variational two-electron reduced-density-matrix (2-RDM) method is applied to computing electronic correlation energies of medium-to-large molecular systems by exploiting the spatial locality of electron correlation within the framework of the cluster-in-molecule (CIM) approximation [S. Li et al., J. Comput. Chem. 23, 238 (2002); J. Chem. Phys. 125, 074109 (2006)]. The 2-RDMs of individual molecular fragments within a molecule are determined, and selected portions of these 2-RDMs are recombined to yield an accurate approximation to the correlation energy of the entire molecule. In addition to extending CIM to the parametric 2-RDM method, we (i) suggest a more systematic selection of atomic-orbital domains than that presented in previous CIM studies and (ii) generalize the CIM method for open-shell quantum systems. The resulting method is tested with a series of polyacetylene molecules, water clusters, and diazobenzene derivatives in minimal and nonminimal basis sets. Calculations show that the computational cost of the method scales linearly with system size. We also compute hydrogen-abstraction energies for a series of hydroxyurea derivatives. Abstraction of hydrogen from hydroxyurea is thought to be a key step in its treatment of sickle cell anemia; the design of hydroxyurea derivatives that oxidize more rapidly is one approach to devising more effective treatments.

Diagnosis and Management of Polycythemia Vera in a Ferret (Mustela putorius furo).

PubMed

Le, Kim; Beaufrère, Hugues; Bassel, Laura L; Wills, Sarah; Laniesse, Delphine; Blois, Shauna L; Smith, Dale A

2016-12-01

A 5-y-old female ferret (Mustela putorius furo) was evaluated for diarrhea, anorexia, and lethargy for 1 wk. Only mild dehydration was detected on physical examination. CBC analysis revealed marked erythrocytosis with an unremarkable plasma biochemistry panel; follow-up CBC analyses revealed a consistent primary erythrocytosis. Whole-body radiographs and abdominal ultrasonography were unremarkable except for a small nephrolith in the right kidney and a small cyst in the left kidney. The plasma erythropoietin level was 17.0 mIU/mL and considered normal. In light of the diagnostic work-up and consistent erythrocytosis, a diagnosis of polycythemia vera (primary erythrocytosis) was made. The initial presentation of diarrhea resolved after treatment with oral metronidazole (20 mg/kg PO BID for 7 d). Treatment for the polycythemia consisted of a phlebotomy initially followed by chemotherapy with hydroxyurea (10 mg/kg PO BID). During the subsequent 12 mo, the hydroxyurea dose adjusted according to follow-up CBC results, and finding an optimal dosage regimen proved to be challenging. One year after the initial diagnosis, the ferret presented to an emergency clinic for acute and severe hemorrhagic diarrhea and died shortly thereafter. The postmortem diagnosis was acute venous infarction of the small and large intestine. To our knowledge, this report is the first to describe the diagnosis and long-term management of polycythemia vera in a ferret and the use of hydroxyurea for this purpose.

Hydroxyurea

MedlinePlus

... on your response to treatment and any side effects that you may experience. Talk to your doctor ... a vitamin), to decrease some of the side effects of this medication. Take this medication exactly as ...

Hydroxycarbamide-Induced Changes in E/beta Thalassemia Red Blood Cells

PubMed Central

Sylvia, Singer T.; Elliott, Vichinsky; Sandra, Larkin; Nancy, Olivieri; Nancy, Sweeters; Frans, Kuypers A.

2010-01-01

In thalassemia, fetal hemoglobin (HbF) augmentation with hydroxycarbamide (also known as hydroxyurea) is not always successful. The expected parallel effects on RBC membrane deformability, cell hydration and membrane phospholipid organization, all important for extending RBC life span and increasing Hb, have been infrequently examined. We analyzed these characteristics in 15 non-transfused E/β 0 thalassemia patients treated with HU (mean 10.2 months). Membrane deformability and cell hydration mildly improved in association with increased HbF levels approaching statistical significance (r = 0.51, p=0.06). All measures improved considerably splenectomized patients. These findings underscore the disappointing results of hydroxyurea treatment in clinical trials; and the importance of examining the effect on red cell characteristics for the development and understanding of HbF-enhancing agents. PMID:18821710

An origin-deficient yeast artificial chromosome triggers a cell cycle checkpoint.

PubMed

van Brabant, A J; Buchanan, C D; Charboneau, E; Fangman, W L; Brewer, B J

2001-04-01

Checkpoint controls coordinate entry into mitosis with the completion of DNA replication. Depletion of nucleotide precursors by treatment with the drug hydroxyurea triggers such a checkpoint response. However, it is not clear whether the signal for this hydroxyurea-induced checkpoint pathway is the presence of unreplicated DNA, or rather the persistence of single-stranded or damaged DNA. In a yeast artificial chromosome (YAC) we have engineered an approximately 170 kb region lacking efficient replication origins that allows us to explore the specific effects of unreplicated DNA on cell cycle progression. Replication of this YAC extends the length of S phase and causes cells to engage an S/M checkpoint. In the absence of Rad9 the YAC becomes unstable, undergoing deletions within the origin-free region.

Ruxolitinib for the treatment of inadequately controlled polycythaemia vera without splenomegaly (RESPONSE-2): a randomised, open-label, phase 3b study.

PubMed

Passamonti, Francesco; Griesshammer, Martin; Palandri, Francesca; Egyed, Miklos; Benevolo, Giulia; Devos, Timothy; Callum, Jeannie; Vannucchi, Alessandro M; Sivgin, Serdar; Bensasson, Caroline; Khan, Mahmudul; Mounedji, Nadjat; Saydam, Guray

2017-01-01

In the pivotal RESPONSE study, ruxolitinib, a Janus kinase (JAK)1 and JAK2 inhibitor, was superior to best available therapy at controlling haematocrit and improving splenomegaly and symptoms in patients with polycythaemia vera with splenomegaly who were inadequately controlled with hydroxyurea. In this study, we assessed the efficacy and safety of ruxolitinib in controlling disease in patients with polycythaemia vera without splenomegaly who need second-line therapy. RESPONSE-2 is a randomised, open-label, phase 3b study assessing ruxolitinib versus best available therapy in patients with polycythaemia vera done in 48 hospitals or clinics across 12 countries in Asia, Australia, Europe, and North America. Eligible patients (aged ≥18 years) with polycythaemia vera, no palpable splenomegaly, and hydroxyurea resistance or intolerance were stratified by their hydroxyurea therapy status (resistance vs intolerance) and randomly assigned (1:1) by an interactive response technology provider using a validated system to receive either oral ruxolitinib 10 mg twice daily or investigator-selected best available therapy (hydroxyurea [at the maximum tolerated dose], interferon or pegylated interferon, pipobroman, anagrelide, approved immunomodulators, or no cytoreductive treatment). Investigators and patients were not masked to treatment assignment; however, the study sponsor was masked to treatment assignment until database lock. The primary endpoint was the proportion of patients achieving haematocrit control at week 28. Analyses were done according to an intention-to-treat principle, including data from all patients randomly assigned to treatment. This study is registered with ClinicalTrials.gov (NCT02038036) and is ongoing but not recruiting patients. Between March 25, 2014, and Feb 11, 2015, of 173 patients assessed for eligibility, 74 patients were randomly assigned to receive ruxolitinib and 75 to receive best available therapy. At randomisation, best available therapy included hydroxyurea (37 [49%] of 75 in the best available therapy group), interferon or pegylated interferon (ten [13%] of 75), pipobroman (five [7%] of 75), lenalidomide (one [1%] of 75), no treatment (21 [28%] of 75), and other (one [1%] of 75). Haematocrit control was achieved in 46 (62%) of 74 ruxolitinib-treated patients versus 14 (19%) of 75 patients who received best available therapy (odds ratio 7·28 [95% CI 3·43-15·45]; p<0·0001). The most frequent haematological adverse events of any grade were anaemia (ten [14%] of 74 in the ruxolitinib group vs two [3%] of 75 in the best available therapy group) and thrombocytopenia (two [3%] vs six [8%]). No cases of grade 3-4 anaemia or thrombocytopenia occurred with ruxolitinib; one patient (1%) reported grade 3-4 anaemia and three patients (4%) reported grade 3-4 thrombocytopenia in the group receiving best available therapy. Frequent grade 3-4 non-haematological adverse events were hypertension (five [7%] of 74 vs three [4%] of 75) and pruritus (0 of 74 vs two [3%] of 75). Serious adverse events occurring in more than 2% of patients in either group, irrespective of cause, included thrombocytopenia (none in the ruxolitinib group vs two [3%] of 75 in the best available therapy group) and angina pectoris (two [3%] of 74 in the ruxolitinib group vs none in the best available therapy group). Two deaths occurred, both in the best available therapy group. RESPONSE-2 met its primary endpoint. The findings of this study indicate that ruxolitinib could be considered a standard of care for second-line therapy in this post-hydroxyurea patient population. Novartis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of a Clinical Pharmacy Service on the Management of Patients in a Sickle Cell Disease Outpatient Center.

PubMed

Han, Jin; Bhat, Shubha; Gowhari, Michel; Gordeuk, Victor R; Saraf, Santosh L

2016-11-01

Ambulatory care clinical pharmacy services have expanded beyond primary care settings, but literature supporting the benefits of clinical pharmacy involvement with patients who have rare diseases such as sickle cell disease (SCD) is lacking. Hydroxyurea is the only agent approved by the U.S. Food and Drug Administration for the treatment of SCD; full benefit in controlling pain episodes and other complications is achieved through monitored escalation to a maximum tolerated dose. The primary objective of this analysis was to evaluate the impact of a newly implemented clinical pharmacy service on the management of patients with SCD. We performed a retrospective cross-sectional analysis of 385 adults with SCD who received care between January 1, 2014, and December 31, 2014, at a single Sickle Cell Outpatient Center that implemented a clinical pharmacy service in August 2013. Data were collected on hydroxyurea dose escalation, immunization completion rates, and health maintenance metrics (screening for nephropathy with microalbuminuria testing, retinopathy with annual retinal examinations, and pulmonary hypertension with echocardiography). The impact of the clinical pharmacy service on quality measurements was evaluated by using univariate and multivariate analyses. The number of pharmacist encounters, defined as a clinic visit when a clinical pharmacist interacted with a patient as documented in the medical records, was associated with an improved hydroxyurea dose escalation rate (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.07-2.05, p=0.02). Immunization rates for the 23-valent pneumococcal polysaccharide vaccine, the 13-valent pneumococcal conjugate vaccine, and influenza vaccine were 66%, 47%, and 62%, respectively. The number of pharmacist encounters was associated with improved immunization completion rates (OR 1.38, 95% CI 1.17-1.62, p<0.001). Improved screening for microalbuminuria (OR 2.14, 95% CI 1.60-2.86, p<0.001) and sickle cell retinopathy (OR 1.16, 95% CI 1.00-1.35, p=0.05) were also associated with the number of pharmacist encounters. A new clinical pharmacy service implemented in managing a rare disease, SCD, was associated with an improved hydroxyurea dose escalation rate, immunization completion rates, and health maintenance metrics. © 2016 Pharmacotherapy Publications, Inc.

Study of alpha hemoglobin stabilizing protein expression in patients with β thalassemia and sickle cell anemia and its impact on clinical severity.

PubMed

Mahmoud, Hanan Mohamed; Shoeib, Ahmed Al-Saiid Hamed; Abd El Ghany, Shereen Mohamed; Reda, Marwa Mohamed; Ragab, Iman Ahmed

2015-12-01

The α hemoglobin stabilizing protein (AHSP) binds α-Hb and prevents its precipitation limiting free α-Hb toxicities. Our aim was to study AHSP expression in β thalassemia syndromes in relation to their clinical severity and to compare it with its level in sickle cell anemia. We compared patients with β-thalassemia (n=37) (β-thalassemia major (BTM) (n=19) and β-thalassemia intermedia (BTI) (n=18)) with 12 patients with sickle cell anemia as regards clinical severity, age at presentation, transfusion dependency, mean pre-transfusion hemoglobin level, use of hydroxyurea and AHSP expression by real time quantitative PCR. Median (and IQR) AHSP expression was significantly higher in patients with sickle cell anemia 2275 (3898) compared to thalassemia 283 (718), P=0.001, with no significant difference between BTM and BTI (P=0.346). It was also significantly higher in non-transfusion dependent patients with β thalassemia (NTDT) compared to transfusion dependent ones (P=0.019), and in patients on hydroxyurea therapy (P<0.001). However, there was no significant difference in its level according to clinical severity score (P=0.946) or splenectomy status (P=0.145). AHSP expression was higher in patients with sickle cell anemia versus thalassemia, with no significant difference between BTM and BTI. Expression was higher in patients with NTDT and on hydroxyurea therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

Low-burden TP53 mutations in chronic phase of myeloproliferative neoplasms: association with age, hydroxyurea administration, disease type and JAK2 mutational status

PubMed Central

Kubesova, B; Pavlova, S; Malcikova, J; Kabathova, J; Radova, L; Tom, N; Tichy, B; Plevova, K; Kantorova, B; Fiedorova, K; Slavikova, M; Bystry, V; Kissova, J; Gisslinger, B; Gisslinger, H; Penka, M; Mayer, J; Kralovics, R; Pospisilova, S; Doubek, M

2018-01-01

The multistep process of TP53 mutation expansion during myeloproliferative neoplasm (MPN) transformation into acute myeloid leukemia (AML) has been documented retrospectively. It is currently unknown how common TP53 mutations with low variant allele frequency (VAF) are, whether they are linked to hydroxyurea (HU) cytoreduction, and what disease progression risk they carry. Using ultra-deep next-generation sequencing, we examined 254 MPN patients treated with HU, interferon alpha-2a or anagrelide and 85 untreated patients. We found TP53 mutations in 50 cases (0.2–16.3% VAF), regardless of disease subtype, driver gene status and cytoreduction. Both therapy and TP53 mutations were strongly associated with older age. Over-time analysis showed that the mutations may be undetectable at diagnosis and slowly increase during disease course. Although three patients with TP53 mutations progressed to TP53-mutated or TP53-wild-type AML, we did not observe a significant age-independent impact on overall survival during the follow-up. Further, we showed that complete p53 inactivation alone led to neither blast transformation nor HU resistance. Altogether, we revealed patient's age as the strongest factor affecting low-burden TP53 mutation incidence in MPN and found no significant age-independent association between TP53 mutations and hydroxyurea. Mutations may persist at low levels for years without an immediate risk of progression. PMID:28744014

Ruxolitinib for the Treatment of Patients With Polycythemia Vera

PubMed Central

Kiladjian, Jean-Jacques; Winton, Elliott F.; Talpaz, Moshe; Verstovsek, Srdan

2015-01-01

SUMMARY Polycythemia vera (PV) is a hematopoietic proliferative disorder associated with Janus-associated kinase (JAK)/signal transducer and activator of transcription (STAT) pathway dysregulation resulting in erythrocytosis and, possibly, leukocytosis and thrombocytosis. Patients diagnosed with PV experience a broad range of symptoms associated with a reduced quality of life, often develop splenomegaly, and have an increased risk of death compared to age-matched subjects without PV. Current treatment options, notably hydroxyurea, help with disease management; however, insufficient efficacy or progressive resistance occurs in some patients, highlighting the need for new treatment options. Ruxolitinib is an oral JAK1/JAK2 inhibitor that has been evaluated in phase 2 and 3 clinical trials in patients with PV who are intolerant of or resistant to hydroxyurea. In this setting, ruxolitinib treatment has demonstrated normalization of blood cell counts, reduction in splenomegaly, and improvements in PV-related symptom burden. PMID:25980454

Hydroxyurea-Mediated Cytotoxicity Without Inhibition of Ribonucleotide Reductase.

PubMed

Liew, Li Phing; Lim, Zun Yi; Cohen, Matan; Kong, Ziqing; Marjavaara, Lisette; Chabes, Andrei; Bell, Stephen D

2016-11-01

In many organisms, hydroxyurea (HU) inhibits class I ribonucleotide reductase, leading to lowered cellular pools of deoxyribonucleoside triphosphates. The reduced levels for DNA precursors is believed to cause replication fork stalling. Upon treatment of the hyperthermophilic archaeon Sulfolobus solfataricus with HU, we observe dose-dependent cell cycle arrest, accumulation of DNA double-strand breaks, stalled replication forks, and elevated levels of recombination structures. However, Sulfolobus has a HU-insensitive class II ribonucleotide reductase, and we reveal that HU treatment does not significantly impact cellular DNA precursor pools. Profiling of protein and transcript levels reveals modulation of a specific subset of replication initiation and cell division genes. Notably, the selective loss of the regulatory subunit of the primase correlates with cessation of replication initiation and stalling of replication forks. Furthermore, we find evidence for a detoxification response induced by HU treatment. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Immunological role of CD4+CD28null T lymphocytes, natural killer cells, and interferon-gamma in pediatric patients with sickle cell disease: relation to disease severity and response to therapy.

PubMed

ElAlfy, Mohsen Saleh; Adly, Amira Abdel Moneam; Ebeid, Fatma Soliman ElSayed; Eissa, Deena Samir; Ismail, Eman Abdel Rahman; Mohammed, Yasser Hassan; Ahmed, Manar Elsayed; Saad, Aya Sayed

2018-06-20

Sickle cell disease (SCD) is associated with alterations in immune phenotypes. CD4 + CD28 null T lymphocytes have pro-inflammatory functions and are linked to vascular diseases. To assess the percentage of CD4 + CD28 null T lymphocytes, natural killer cells (NK), and IFN-gamma levels, we compared 40 children and adolescents with SCD with 40 healthy controls and evaluated their relation to disease severity and response to therapy. Patients with SCD steady state were studied, focusing on history of frequent vaso-occlusive crisis, hydroxyurea therapy, and IFN-gamma levels. Analysis of CD4 + CD28 null T lymphocytes and NK cells was done by flow cytometry. Liver and cardiac iron overload were assessed. CD4 + CD28 null T lymphocytes, NK cells, and IFN-gamma levels were significantly higher in patients than controls. Patients with history of frequent vaso-occlusive crisis and those with vascular complications had higher percentage of CD4 + CD28 null T lymphocytes and IFN-gamma while levels were significantly lower among hydroxyurea-treated patients. CD4 + CD28 null T lymphocytes were positively correlated to transfusional iron input while these cells and IFN-gamma were negatively correlated to cardiac T2* and duration of hydroxyurea therapy. NK cells were correlated to HbS and indirect bilirubin. Increased expression of CD4 + CD28 null T lymphocytes highlights their role in immune dysfunction and pathophysiology of SCD complications.

Philadelphia-negative classical myeloproliferative neoplasms: critical concepts and management recommendations from European LeukemiaNet.

PubMed

Barbui, Tiziano; Barosi, Giovanni; Birgegard, Gunnar; Cervantes, Francisco; Finazzi, Guido; Griesshammer, Martin; Harrison, Claire; Hasselbalch, Hans Carl; Hehlmann, Rudiger; Hoffman, Ronald; Kiladjian, Jean-Jacques; Kröger, Nicolaus; Mesa, Ruben; McMullin, Mary F; Pardanani, Animesh; Passamonti, Francesco; Vannucchi, Alessandro M; Reiter, Andreas; Silver, Richard T; Verstovsek, Srdan; Tefferi, Ayalew

2011-02-20

We present a review of critical concepts and produce recommendations on the management of Philadelphia-negative classical myeloproliferative neoplasms, including monitoring, response definition, first- and second-line therapy, and therapy for special issues. Key questions were selected according the criterion of clinical relevance. Statements were produced using a Delphi process, and two consensus conferences involving a panel of 21 experts appointed by the European LeukemiaNet (ELN) were convened. Patients with polycythemia vera (PV) and essential thrombocythemia (ET) should be defined as high risk if age is greater than 60 years or there is a history of previous thrombosis. Risk stratification in primary myelofibrosis (PMF) should start with the International Prognostic Scoring System (IPSS) for newly diagnosed patients and dynamic IPSS for patients being seen during their disease course, with the addition of cytogenetics evaluation and transfusion status. High-risk patients with PV should be managed with phlebotomy, low-dose aspirin, and cytoreduction, with either hydroxyurea or interferon at any age. High-risk patients with ET should be managed with cytoreduction, using hydroxyurea at any age. Monitoring response in PV and ET should use the ELN clinicohematologic criteria. Corticosteroids, androgens, erythropoiesis-stimulating agents, and immunomodulators are recommended to treat anemia of PMF, whereas hydroxyurea is the first-line treatment of PMF-associated splenomegaly. Indications for splenectomy include symptomatic portal hypertension, drug-refractory painful splenomegaly, and frequent RBC transfusions. The risk of allogeneic stem-cell transplantation-related complications is justified in transplantation-eligible patients whose median survival time is expected to be less than 5 years.

Philadelphia-Negative Classical Myeloproliferative Neoplasms: Critical Concepts and Management Recommendations From European LeukemiaNet

PubMed Central

Barbui, Tiziano; Barosi, Giovanni; Birgegard, Gunnar; Cervantes, Francisco; Finazzi, Guido; Griesshammer, Martin; Harrison, Claire; Hasselbalch, Hans Carl; Hehlmann, Rudiger; Hoffman, Ronald; Kiladjian, Jean-Jacques; Kröger, Nicolaus; Mesa, Ruben; McMullin, Mary F.; Pardanani, Animesh; Passamonti, Francesco; Vannucchi, Alessandro M.; Reiter, Andreas; Silver, Richard T.; Verstovsek, Srdan; Tefferi, Ayalew

2011-01-01

We present a review of critical concepts and produce recommendations on the management of Philadelphia-negative classical myeloproliferative neoplasms, including monitoring, response definition, first- and second-line therapy, and therapy for special issues. Key questions were selected according the criterion of clinical relevance. Statements were produced using a Delphi process, and two consensus conferences involving a panel of 21 experts appointed by the European LeukemiaNet (ELN) were convened. Patients with polycythemia vera (PV) and essential thrombocythemia (ET) should be defined as high risk if age is greater than 60 years or there is a history of previous thrombosis. Risk stratification in primary myelofibrosis (PMF) should start with the International Prognostic Scoring System (IPSS) for newly diagnosed patients and dynamic IPSS for patients being seen during their disease course, with the addition of cytogenetics evaluation and transfusion status. High-risk patients with PV should be managed with phlebotomy, low-dose aspirin, and cytoreduction, with either hydroxyurea or interferon at any age. High-risk patients with ET should be managed with cytoreduction, using hydroxyurea at any age. Monitoring response in PV and ET should use the ELN clinicohematologic criteria. Corticosteroids, androgens, erythropoiesis-stimulating agents, and immunomodulators are recommended to treat anemia of PMF, whereas hydroxyurea is the first-line treatment of PMF-associated splenomegaly. Indications for splenectomy include symptomatic portal hypertension, drug-refractory painful splenomegaly, and frequent RBC transfusions. The risk of allogeneic stem-cell transplantation–related complications is justified in transplantation-eligible patients whose median survival time is expected to be less than 5 years. PMID:21205761

Structure and stability of the N-hydroxyurea dimer: Post-Hartree-Fock quantum mechanical study

NASA Astrophysics Data System (ADS)

Jabalameli, Ali; Venkatraman, Ramaiyer; Nowek, Andrzej; Sullivan, Richard H.

2000-10-01

The potential energy surface (PES) search of the N-hydroxyurea dimer was searched with second-order Møller-Plesset perturbation theory (MP2) and the 6-31G(d,p) basis set. Eight local minimum energy structures have been found. Four of them have relatively strong (ΔE˜-10 to -13 kcal/mol) intermolecular interactions and the others are moderately strongly interacting species (ΔE˜-3 to -7 kcal/mol). Final estimation of interaction energies was performed using the larger 6-311G(df,pd) and 6-311G(2df,2pd) basis sets. The predicted interaction energies are ΔE=-14.26 kcal/mol and -3.43 kcal/mol for the strongest and the weakest interacting forms of the studied complex, respectively, at the MP2/6-311G(2df,2pd)//MP2/6-31G(d,p) level of theory. The self-consistent field (SCF) interaction energy decomposition indicates the important influence of the deformation term magnitude on ΔE(SCF). The calculated electron correlation contribution to ΔE(MP2) depends on the geometry of the system and varies from -0.5 to -5 kcal/mol. The estimated influence of water on the stability (free energy of hydration) of N-hydroxyurea dimers using the self-consistent isodensity polarized continuum (SCI-PCM) model of solvation varies from ˜-11 kcal/mol to ˜-21 kcal/mol. The forms predicted to be more strongly interacting species in gas phase are less influenced by hydration than the more weakly interacting ones.

Blood transfusion for preventing primary and secondary stroke in people with sickle cell disease.

PubMed

Wang, Winfred C; Dwan, Kerry

2013-11-14

In sickle cell disease, a common inherited haemoglobin disorder, abnormal haemoglobin distorts red blood cells, causing anaemia, vaso-occlusion and dysfunction in most body organs. Without intervention, stroke affects around 10% of children with sickle cell anaemia (HbSS) and recurrence is likely. Chronic blood transfusion dilutes the sickled red blood cells, reducing the risk of vaso-occlusion and stroke. However, side effects can be severe. To assess risks and benefits of chronic blood transfusion regimens in people with sickle cell disease to prevent first stroke or recurrences. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register, comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and conference proceedings.Date of the latest search of the Group's Haemoglobinopathies Trials Register: 28 January 2013. Randomised and quasi-randomised controlled trials comparing blood transfusion as prophylaxis for stroke in people with sickle cell disease to alternative or no treatment. Both authors independently assessed the risk of bias of the included trials and extracted data. Searches identified three eligible randomised trials (n = 342). The first two trials addressed the use of chronic transfusion to prevent primary stroke; the third utilized the drug hydroxycarbamide (hydroxyurea) and phlebotomy to prevent both recurrent (secondary) stroke and iron overload in patients who had already experienced an initial stroke. In the first trial (STOP) a chronic transfusion regimen for maintaining sickle haemoglobin lower than 30% was compared with standard care in 130 children with sickle cell disease judged (through transcranial Doppler ultrasonography) as high-risk for first stroke. During the trial, 11 children in the standard care group suffered a stroke compared to one in the transfusion group, odds ratio 0.08 (95% confidence interval 0.01 to 0.66). This meant the trial was terminated early. The transfusion group had a high complications rate, including iron overload, alloimmunisation, and transfusion reactions. The second trial (STOP II) investigated risk of stroke when transfusion was stopped after at least 30 months in this population. The trial closed early due to a significant difference in risk of stroke between participants who stopped transfusion and those who continued as measured by reoccurrence of abnormal velocities on Doppler examination or the occurrence of overt stroke in the group that stopped transfusion. The third trial (SWiTCH) was a non-inferiority trial comparing transfusion and iron chelation (standard management) with hydroxyurea and phlebotomy (alternative treatment) with the combination endpoint of prevention of stroke recurrence and reduction of iron overload. This trial was stopped early after enrolment and follow up of 133 children because of analysis showing futility in reaching the composite primary endpoint. The stroke rate (seven strokes on hydroxyurea and phlebotomy, none on transfusion and chelation, odds ratio 16.49 (95% confidence interval 0.92 to 294.84)) was within the non-inferiority margin, but the liver iron content was not better in the alternative arm. The STOP trial demonstrated a significantly reduced risk of stroke in participants with abnormal transcranial Doppler ultrasonography velocities receiving regular blood transfusions. The follow-up trial (STOP 2) indicated that individuals may revert to former risk status if transfusion is discontinued. The degree of risk must be balanced against the burden of chronic transfusions. The combination of hydroxyurea and phlebotomy is not as effective as "standard" transfusion and chelation in preventing secondary stroke and iron overload. Ongoing multicentre trials are investigating the use of chronic transfusion to prevent silent infarcts, the use of hydroxyurea as an alternative to transfusion in children with abnormal transcranial Doppler ultrasonography velocities, and the use of hydroxyurea to prevent conversion of transcranial Doppler ultrasonography velocities from conditional (borderline) to abnormal values.

Distinct RAD51 Associations with RAD52 and BCCIP in Response to DNA Damage and Replication Stress

PubMed Central

Wray, Justin; Liu, Jingmei; Nickoloff, Jac A.; Shen, Zhiyuan

2009-01-01

RAD51 has critical roles in homologous recombination (HR) repair of DNA double-strand breaks (DSB) and restarting stalled or collapsed replication forks. In yeast, Rad51 function is facilitated by Rad52 and other “mediators.” Mammalian cells express RAD52, but BRCA2 may have supplanted RAD52 in mediating RAD51 loading onto ssDNA. BCCIP interacts with BRCA2, and both proteins are important for RAD51 focus formation after ionizing radiation and HR repair of DSBs. Nonetheless, mammalian RAD52 shares biochemical activities with yeast Rad52, including RAD51 binding and single-strand annealing, suggesting a conserved role in HR. Because RAD52 and RAD51 associate, and RAD51 and BCCIP associate, we investigated the colocalization of RAD51 with BCCIP and RAD52 in human cells. We found that RAD51 colocalizes with BCCIP early after ionizing radiation, with RAD52 later, and there was little colocalization of BCCIP and RAD52. RAD52 foci are induced to a greater extent by hydroxyurea, which stalls replication forks, than by ionizing radiation. Using fluorescence recovery after photo bleaching, we show that RAD52 mobility is reduced to a greater extent by hydroxyurea than ionizing radiation. However, BCCIP showed no changes in mobility after hydroxyurea or ionizing radiation. We propose that BCCIP-dependent repair of DSBs by HR is an early RAD51 response to ionizing radiation–induced DNA damage, and that RAD52-dependent HR occurs later to restart a subset of blocked or collapsed replication forks. RAD52 and BRCA2 seem to act in parallel pathways, suggesting that targeting RAD52 in BRCA2-deficient tumors may be effective in treating these tumors. PMID:18413737

Impact of cycling cells and cell cycle regulation on Hydra regeneration.

PubMed

Buzgariu, Wanda; Wenger, Yvan; Tcaciuc, Nina; Catunda-Lemos, Ana-Paula; Galliot, Brigitte

2018-01-15

Hydra tissues are made from three distinct populations of stem cells that continuously cycle and pause in G2 instead of G1. To characterize the role of cell proliferation after mid-gastric bisection, we have (i) used flow cytometry and classical markers to monitor cell cycle modulations, (ii) quantified the transcriptomic regulations of 202 genes associated with cell proliferation during head and foot regeneration, and (iii) compared the impact of anti-proliferative treatments on regeneration efficiency. We confirm two previously reported events: an early mitotic wave in head-regenerating tips, when few cell cycle genes are up-regulated, and an early-late wave of proliferation on the second day, preceded by the up-regulation of 17 cell cycle genes. These regulations appear more intense after mid-gastric bisection than after decapitation, suggesting a position-dependent regulation of cell proliferation during head regeneration. Hydroxyurea, which blocks S-phase progression, delays head regeneration when applied before but not after bisection. This result is consistent with the fact that the Hydra central region is enriched in G2-paused adult stem cells, poised to divide upon injury, thus forming a necessary constitutive pro-blastema. However a prolonged exposure to hydroxyurea does not block regeneration as cells can differentiate apical structures without traversing S-phase, and also escape in few days the hydroxyurea-induced S-phase blockade. Thus Hydra head regeneration, which is a fast event, is highly plastic, relying on large stocks of adult stem cells paused in G2 at amputation time, which immediately divide to proliferate and/or differentiate apical structures even when S-phase is blocked. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

A mutated dph3 gene causes sensitivity of Schizosaccharomyces pombe cells to cytotoxic agents.

PubMed

Villahermosa, Desirée; Knapp, Karen; Fleck, Oliver

2017-12-01

Dph3 is involved in diphthamide modification of the eukaryotic translation elongation factor eEF2 and in Elongator-mediated modifications of tRNAs, where a 5-methoxycarbonyl-methyl moiety is added to wobble uridines. Lack of such modifications affects protein synthesis due to inaccurate translation of mRNAs at ribosomes. We have discovered that integration of markers at the msh3 locus of Schizosaccharomyces pombe impaired the function of the nearby located dph3 gene. Such integrations rendered cells sensitive to the cytotoxic drugs hydroxyurea and methyl methanesulfonate. We constructed dph3 and msh3 strains with mutated ATG start codons (ATGmut), which allowed investigating drug sensitivity without potential interference by marker insertions. The dph3-ATGmut and a dph3::loxP-ura4-loxM gene disruption strain, but not msh3-ATGmut, turned out to be sensitive to hydroxyurea and methyl methanesulfonate, likewise the strains with cassettes integrated at the msh3 locus. The fungicide sordarin, which inhibits diphthamide modified eEF2 of Saccharomyces cerevisiae, barely affected survival of wild type and msh3Δ S. pombe cells, while the dph3Δ mutant was sensitive. The msh3-ATG mutation, but not dph3Δ or the dph3-ATG mutation caused a defect in mating-type switching, indicating that the ura4 marker at the dph3 locus did not interfere with Msh3 function. We conclude that Dph3 is required for cellular resistance to the fungicide sordarin and to the cytotoxic drugs hydroxyurea and methyl methanesulfonate. This is likely mediated by efficient translation of proteins in response to DNA damage and replication stress.

Key endothelial cell angiogenic mechanisms are stimulated by the circulating milieu in sickle cell disease and attenuated by hydroxyurea

PubMed Central

Lopes, Flavia C. M.; Traina, Fabiola; Almeida, Camila B.; Leonardo, Flavia C.; Franco-Penteado, Carla F.; Garrido, Vanessa T.; Colella, Marina P.; Soares, Raquel; Olalla-Saad, Sara T.; Costa, Fernando F.; Conran, Nicola

2015-01-01

As hypoxia-induced inflammatory angiogenesis may contribute to the manifestations of sickle cell disease, we compared the angiogenic molecular profiles of plasma from sickle cell disease individuals and correlated these with in vitro endothelial cell-mediated angiogenesis-stimulating activity and in vivo neovascularization. Bioplex demonstrated that plasma from patients with steady-state sickle cell anemia contained elevated concentrations of pro-angiogenic factors (angiopoietin-1, basic fibroblast growth factor, vascular endothelial growth factor, vascular endothelial growth factor-D and placental growth factor) and displayed potent pro-angiogenic activity, significantly increasing endothelial cell proliferation, migration and capillary-like structure formation. In vivo neovascularization of Matrigel plugs was significantly greater in sickle cell disease mice than in non-sickle cell disease mice, consistent with an up-regulation of angiogenesis in the disease. In plasma from patients with hemoglobin SC disease without proliferative retinopathy, anti-angiogenic endostatin and thrombospondin-2 were significantly elevated. In contrast, plasma from hemoglobin SC individuals with proliferative retinopathy had a pro-angiogenic profile and more significant effects on endothelial cell proliferation and capillary formation than plasma from patients without retinopathy. Hydroxyurea therapy was associated with significant reductions in plasma angiogenic factors and inhibition of endothelial cell-mediated angiogenic mechanisms and neovascularization. Thus, individuals with sickle cell anemia or hemoglobin SC disease with retinopathy present a highly angiogenic circulating milieu, capable of stimulating key endothelial cell-mediated angiogenic mechanisms. Combination anti-angiogenic therapy to prevent the progression of unregulated neovascularization and associated manifestations in sickle cell disease, such as pulmonary hypertension, may be indicated; furthermore, the benefits and drawbacks of the potent anti-angiogenic effects of hydroxyurea should be clarified. PMID:25769545

Therapeutic superiority and safety of combined hydroxyurea with recombinant human erythropoietin over hydroxyurea in young β-thalassemia intermedia patients.

PubMed

Elalfy, Mohsen S; Adly, Amira A M; Ismail, Eman A; Elhenawy, Yasmine I; Elghamry, Islam R

2013-12-01

To assess the efficacy and safety of combined hydroxyurea (HU) and recombinant human erythropoietin (rHuEPO) in β-thalassemia intermedia (TI) patients compared with single HU therapy. An interventional prospective randomized study registered in the ClinicalTrials.gov (NCT01624038) was performed on 80 TI patients (≤ 18 yr) divided into group A (40 patients received combined HU and rHuEPO) and group B (40 patients received single HU therapy). Baseline serum EPO levels were measured, and both groups were followed up for a mean period of 1 yr with regular assessment of transfusion requirements, blood pressure, ferritin, liver and renal functions, hemoglobin, and HbF. Quality of life (QoL) was assessed at the start and end of the study. Transfusion frequency and index were significantly decreased, while QoL was increased in group A compared with group B where 85% of patients showed improvement on combined therapy compared with 50% of patients on HU. Hemoglobin and HbF were significantly increased in both TI groups; however, this was more evident in group A than in group B. Also, 37.5% of patients in group A became transfusion-independent compared with 15% in group B. EPO levels were negatively related to increments of hemoglobin and HbF. Splenectomized patients and those with initial HbF% >40% had the best response to combined therapy. No serious adverse events necessitating discontinuation of therapy in both groups. HU was effective in management of TI; however, combination with rHuEPO gave a superior therapeutic effect resulting in the best clinical and hematological responses without adverse events. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Technology Access and Smartphone App Preferences for Medication Adherence in Adolescents and Young Adults With Sickle Cell Disease.

PubMed

Badawy, Sherif M; Thompson, Alexis A; Liem, Robert I

2016-05-01

Hydroxyurea is the only Food and Drug Administration approved medication for sickle cell disease (SCD) with short- and long-term benefits for both morbidity and mortality. However, hydroxyurea underutilization and adherence remain challenges for patients with SCD. The objectives of this study were to determine access to technology among adolescents and young adults (AYA) with SCD and to identify their preferred technology-based strategies for improving medication adherence. A cross-sectional survey was administered in a variety of clinical settings from October 2014 through May 2015 to AYA (12-22 years) with SCD (all genotypes) followed in a Comprehensive Sickle Cell Program. Eighty of 107 eligible participants completed the survey for a 75% response rate. Participants (51% female, 94% Black) had a mean age of 15.3 ± 2.8 years. Most participants (75%) were on a daily medication with about half on hydroxyurea. Forgetfulness (67%) was the most common barrier to medication adherence. The majority of participants (85%) owned smartphones and either owned or had access to electronic tablets (83%), laptops (72%), or desktops (70%). Of the proposed smartphone app features, daily medication reminders were ranked first most frequently, followed by education about SCD, adherence text prompts, education about SCD medications, and medication log. The majority of our AYA with SCD owned smartphones and had access to other electronic devices. Our survey results provided valuable insight into the preferred app features and optimal strategies for developing technology-based interventions, such as a multicomponent app, to increase medication adherence for AYA with SCD or other chronic conditions. © 2016 Wiley Periodicals, Inc.

Interventions for chronic kidney disease in people with sickle cell disease

PubMed Central

Roy, Noemi BA; Fortin, Patricia M; Bull, Katherine R; Doree, Carolyn; Trivella, Marialena; Hopewell, Sally; Estcourt, Lise J

2017-01-01

Background Sickle cell disease (SCD) is one of the commonest severe monogenic disorders in the world, due to the inheritance of two abnormal haemoglobin (beta-globin) genes. SCD can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Kidney disease is a frequent and potentially severe complication in people with SCD. Chronic kidney disease is defined as abnormalities of kidney structure or function, present for more than three months. Sickle cell nephropathy refers to the spectrum of kidney complications in SCD. Glomerular damage is a cause of microalbuminuria and can develop at an early age in children with SCD, and increases in prevalence in adulthood. In people with sickle cell nephropathy, outcomes are poor as a result of the progression to proteinuria and chronic kidney insufficiency. Up to 12% of people who develop sickle cell nephropathy will develop end-stage renal disease. Objectives To assess the effectiveness of any intervention in preventing or reducing kidney complications or chronic kidney disease in people with SCD (including red blood cell transfusions, hydroxyurea and angiotensin-converting enzyme inhibitor (ACEI)), either alone or in combination with each other. Search methods We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to 05 April 2016. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register: 13 April 2017. Selection criteria Randomised controlled trials comparing interventions to prevent or reduce kidney complications or chronic kidney disease in people with SCD. There were no restrictions by outcomes examined, language or publication status. Data collection and analysis Two authors independently assessed trial eligibility, extracted data and assessed the risk of bias. Main results We included two trials with 215 participants. One trial was published in 2011 and included 193 children aged 9 months to 18 months, and compared treatment with hydroxyurea to placebo. The second trial was published in 1998 and included 22 adults with normal blood pressure and microalbuminuria and compared ACEI to placebo. We rated the quality of evidence as low to very low across different outcomes according to GRADE methodology. This was due to trials having: a high or unclear risk of bias including attrition and detection bias; indirectness (the available evidence was for children aged 9 months to 18 months in one trial and a small and select adult sample size in a second trial); and imprecise outcome effect estimates of significant benefit or harm. Hydroxyurea versus placebo We are very uncertain if hydroxyurea reduces or prevents progression of kidney disease (assessed by change in glomerular filtration rate), or reduces hyperfiltration in children aged 9 to 18 months, mean difference (MD) 0.58 (95% confidence interval (CI) -14.60 to 15.76 (mL/min per 1.73 m2)) (one study; 142 participants; very low-quality evidence). In children aged 9 to 18 months, hydroxyurea may improve the ability to concentrate urine, MD 42.23 (95% CI 12.14 to 72.32 (mOsm/kg)) (one study; 178 participants; low-quality evidence). Hydroxyurea may make little or no difference to SCD-related serious adverse events including: incidence of acute chest syndrome, risk ratio (RR) 0.39 (99% CI 0.13 to 1.16); painful crisis, RR 0.68 (99% CI 0.45 to 1.02); and hospitalisations, RR 0.83 (99% CI 0.68 to 1.01) (one study, 193 participants; low-quality evidence). No deaths occurred in the trial. Quality of life was not reported. ACEI versus placebo We are very uncertain if ACEI reduces proteinuria in adults with SCD who have normal blood pressure and microalbuminuria, MD - 49.00 (95% CI -124.10 to 26.10 (mg per day)) (one study; 22 participants; very low-quality evidence). We are very uncertain if ACEI reduce or prevent kidney disease as measured by creatinine clearance. The authors state that creatinine clearance remained constant over six months in both groups, but no comparative data were provided (very low-quality evidence). All-cause mortality, serious adverse events and quality of life were not reported. Authors’ conclusions In young children aged 9 months to 18 months, we are very uncertain if hydroxyurea improves glomerular filtration rate or reduces hyperfiltration, but it may improve young children’s ability to concentrate urine and may make little or no difference on the incidence of acute chest syndrome, painful crises and hospitalisations. We are very uncertain if giving ACEI to adults with normal blood pressure and microalbuminuria has any effect on preventing or reducing kidney complications. This review identified no trials that looked at red cell transfusions nor any combinations of interventions to prevent or reduce kidney complications. Due to lack of evidence this review cannot comment on the management of either children aged over 18 months or adults with any known genotype of SCD. We have identified a lack of adequately-designed and powered studies, and no ongoing trials which address this critical question. Trials of hydroxyurea, ACEI or red blood cell transfusion in older children and adults are urgently needed to determine any effect on prevention or reduction kidney complications in people with SCD. PMID:28672087

Beyond hydroxyurea: new and old drugs in the pipeline for sickle cell disease

PubMed Central

2016-01-01

Despite Food and Drug Administration (FDA) approval of hydroxyurea to reduce the frequency of vaso-occlusive episodes, sickle cell disease (SCD) has continued to be treated primarily with analgesics for pain relief. However, elucidation of the multiple pathophysiologic mechanisms leading to vaso-occlusion and tissue injury in SCD has now resulted in a burgeoning effort to identify new treatment modalities to prevent or ameliorate the consequences of the disease. Development of new drugs as well as investigation of drugs previously used in other settings have targeted cell adhesion, inflammatory pathways, upregulation of hemoglobin F, hemoglobin polymerization and sickling, coagulation, and platelet activation. Although these efforts have not yet yielded drugs ready for FDA approval, several early studies have been extremely encouraging. Moreover, the marked increase in clinical pharmaceutical research addressing SCD and the new and old drugs in the pipeline make it reasonable to expect that we will soon have new treatments for SCD. PMID:26758919

Alpha-synuclein functions in the nucleus to protect against hydroxyurea-induced replication stress in yeast

PubMed Central

Liu, Xianpeng; Lee, Yong Joo; Liou, Liang-Chun; Ren, Qun; Zhang, Zhaojie; Wang, Shaoxiao; Witt, Stephan N.

2011-01-01

Hydroxyurea (HU) inhibits ribonucleotide reductase (RNR), which catalyzes the rate-limiting synthesis of deoxyribonucleotides for DNA replication. HU is used to treat HIV, sickle-cell anemia and some cancers. We found that, compared with vector control cells, low levels of alpha-synuclein (α-syn) protect S. cerevisiae cells from the growth inhibition and reactive oxygen species (ROS) accumulation induced by HU. Analysis of this effect using different α-syn mutants revealed that the α-syn protein functions in the nucleus and not the cytoplasm to modulate S-phase checkpoint responses: α-syn up-regulates histone acetylation and RNR levels, maintains helicase minichromosome maintenance protein complexes (Mcm2–7) on chromatin and inhibits HU-induced ROS accumulation. Strikingly, when residues 2–10 or 96–140 are deleted, this protective function of α-syn in the nucleus is abolished. Understanding the mechanism by which α-syn protects against HU could expand our knowledge of the normal function of this neuronal protein. PMID:21642386

Laser Photobiomodulation for a Complex Patient with Severe Hydroxyurea-Induced Oral Ulcerations.

PubMed

Cabras, Marco; Cafaro, Adriana; Gambino, Alessio; Broccoletti, Roberto; Romagnoli, Ercole; Marina, Davide; Arduino, Paolo G

2016-01-01

Patients affected by polycythemia vera (PV), a myeloproliferative neoplasm characterized by an elevated red blood cell mass, are at high risk of vascular and thrombotic complications. Conventional therapeutic options aim at reducing vascular and thrombotic risk; low-dose aspirin and phlebotomy are first-line recommendations, for patients at low risk of thrombotic events, whereas cytoreductive therapy, usually hydroxyurea (HU) or interferon alpha, is recommended for high-risk patients. In the present study, we report the case of a patient with persistent oral ulcerations, possibly related to long-lasting HU treatment, firstly treated with topic and systemic corticosteroids and then more effectively with the addition of low-level laser therapy. Laser photobiomodulation has achieved pain control and has contributed to the healing of oral ulcers without any adverse effect; this has permitted a reduction in the dose of systemic corticosteroids and the suspension of the use of the topic ones, due to the long-term stability of oral health, even after the interruption of low-level laser therapy sessions.

Laser Photobiomodulation for a Complex Patient with Severe Hydroxyurea-Induced Oral Ulcerations

PubMed Central

Cabras, Marco; Cafaro, Adriana; Broccoletti, Roberto; Romagnoli, Ercole; Marina, Davide

2016-01-01

Patients affected by polycythemia vera (PV), a myeloproliferative neoplasm characterized by an elevated red blood cell mass, are at high risk of vascular and thrombotic complications. Conventional therapeutic options aim at reducing vascular and thrombotic risk; low-dose aspirin and phlebotomy are first-line recommendations, for patients at low risk of thrombotic events, whereas cytoreductive therapy, usually hydroxyurea (HU) or interferon alpha, is recommended for high-risk patients. In the present study, we report the case of a patient with persistent oral ulcerations, possibly related to long-lasting HU treatment, firstly treated with topic and systemic corticosteroids and then more effectively with the addition of low-level laser therapy. Laser photobiomodulation has achieved pain control and has contributed to the healing of oral ulcers without any adverse effect; this has permitted a reduction in the dose of systemic corticosteroids and the suspension of the use of the topic ones, due to the long-term stability of oral health, even after the interruption of low-level laser therapy sessions. PMID:27957350

Genomic mapping of single-stranded DNA in hydroxyurea-challenged yeasts identifies origins of replication.

PubMed

Feng, Wenyi; Collingwood, David; Boeck, Max E; Fox, Lindsay A; Alvino, Gina M; Fangman, Walton L; Raghuraman, Mosur K; Brewer, Bonita J

2006-02-01

During DNA replication one or both strands transiently become single stranded: first at the sites where initiation of DNA synthesis occurs (known as origins of replication) and subsequently on the lagging strands of replication forks as discontinuous Okazaki fragments are generated. We report a genome-wide analysis of single-stranded DNA (ssDNA) formation in the presence of hydroxyurea during DNA replication in wild-type and checkpoint-deficient rad53 Saccharomyces cerevisiae cells. In wild-type cells, ssDNA was first observed at a subset of replication origins and later 'migrated' bi-directionally, suggesting that ssDNA formation is associated with continuously moving replication forks. In rad53 cells, ssDNA was observed at virtually every known origin, but remained there over time, suggesting that replication forks stall. Telomeric regions seemed to be particularly sensitive to the loss of Rad53 checkpoint function. Replication origins in Schizosaccharomyces pombe were also mapped using our method.

Replication in hydroxyurea: it's a matter of time.

PubMed

Alvino, Gina M; Collingwood, David; Murphy, John M; Delrow, Jeffrey; Brewer, Bonita J; Raghuraman, M K

2007-09-01

Hydroxyurea (HU) is a DNA replication inhibitor that negatively affects both the elongation and initiation phases of replication and triggers the "intra-S phase checkpoint." Previous work with budding yeast has shown that, during a short exposure to HU, MEC1/RAD53 prevent initiation at some late S phase origins. In this study, we have performed microarray experiments to follow the fate of all origins over an extended exposure to HU. We show that the genome-wide progression of DNA synthesis, including origin activation, follows the same pattern in the presence of HU as in its absence, although the time frames are very different. We find no evidence for a specific effect that excludes initiation from late origins. Rather, HU causes S phase to proceed in slow motion; all temporal classes of origins are affected, but the order in which they become active is maintained. We propose a revised model for the checkpoint response to HU that accounts for the continued but slowed pace of the temporal program of origin activation.

Study on reduction and back extraction of Pu(IV) by urea derivatives in nitric acid conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, G.A.; Xiao, S.T.; Yan, T.H.

2013-07-01

The reduction kinetics of Pu(IV) by hydroxyl-semicarbazide (HSC), hydroxyurea (HU) and di-hydroxyurea (DHU) in nitric acid solutions were investigated separately with adequate kinetic equations. In addition, counter-current cascade experiments were conducted for Pu split from U in nitric acid media using three kinds of reductant, respectively. The results show that urea derivatives as a kind of novel salt-free reductant can reduce Pu(IV) to Pu(III) rapidly in the nitric acid solutions. The stripping experimental results showed that Pu(IV) in the organic phase can be stripped rapidly to the aqueous phase by the urea derivatives, and the separation factors of plutonium /uraniummore » can reach more than 10{sup 4}. This indicates that urea derivatives is a kind of promising salt-free agent for uranium/plutonium separation. In addition, the complexing effect of HSC with Np(IV) was revealed, and Np(IV) can be back-extracted by HSC with a separation factor of about 20.« less

Busulfan is effective second-line therapy for older patients with Philadelphia-negative myeloproliferative neoplasms intolerant of or unresponsive to hydroxyurea.

PubMed

Douglas, Genevieve; Harrison, Claire; Forsyth, Cecily; Bennett, Michael; Stevenson, William; Hounsell, John; Ratnasingam, Sumita; Ritchie, David; Ross, David M; Grigg, Andrew

2017-01-01

Hydroxyurea (Hu) is widely used as first-line cytoreductive therapy for patients with high-risk Philadelphia-negative myeloproliferative neoplasms (Ph-neg MPN), but a small proportion of patients have refractory disease or experience adverse effects. Studies have demonstrated busulfan (Bu) to be an active first-line agent, but data on its role as second-line or later therapy are minimal. To evaluate its efficacy and safety in this context, we undertook a multicenter audit of Ph-neg MPN patients who had received Bu as therapy for Hu intolerance or failure. Of 51 patients identified, 38 (75%) achieved either complete or partial hematological response following at least one Bu cycle. Bu was generally well tolerated, with only 21/135 (15%) cycles complicated by adverse effects, predominantly cytopenia; only 6% of cycles were ceased due to treatment complications. Bu is an effective and well-tolerated agent in patients with Ph-neg MPN in the setting of Hu intolerance or unresponsiveness.

Influence of Urea, Hydroxyurea, and Thiourea on Meloidogyne javanica and Infected Excised Tomato Roots in Culture

PubMed Central

Glazer, I.; Orion, D.

1984-01-01

Urea (U), hydroxyurea (HU), and thiourea (TU), in various concentrations, were added to chemically defined plant tissue culture medium on which Meloidogyne javanica was reared on excised tomato roots. Concentrations as low as 3 ppm HU or 12 ppm TU inhibited nematode maturation by 70-90% 4 weeks after inoculation, and the coenocytes in the parasitized tissue were poorly developed. Gall weight was also inhibited by 50% in cultures treated with 3 and 6 ppm HU. However, exposing juveniles of M. javanica and Tylenchulus semipenetrans or juveniles and adults of Pratylenchus thornei to increasing concentrations of HU or TU, up to 100 ppm, was not lethal. These two urea derivatives still inhibited nematode maturation when the infected region of the root was not in direct contact with the chemicals. Therefore, we suggest that these urea derivatives inhibit nematode development by affecting the plant metabolism essential to coenocyte formation, an occurrence similar to the hypersensitive reaction in a naturally resistant plant. PMID:19295888

Cellular biophysical markers of hydroxyurea treatment in sickle cell disease

NASA Astrophysics Data System (ADS)

So, Peter T. C.; Hosseini, Poorya; Abidi, Sabia Z.; Du, E.; Papageorgiou, Dimitrios P.; Park, YongKeun; Higgins, John; Kato, Gregory J.; Suresh, Subra; Dao, Ming; Yaqoob, Zahid

2017-04-01

Using a common-path interferometric technique, we measure biomechanical and morphological properties of individual red blood cells in SCD patients as a function of cell density, and investigate the correlation of these biophysical properties with drug intake as well as other clinically measured parameters.

NTP-CERHR Expert Panel Report on the reproductive and developmental toxicity of hydroxyurea

EPA Science Inventory

The National Toxicology Program (NTP) and the National Institute of Environmental Health Sciences (NIEHS) established the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR) in June 1998. The purpose of CERHR is to provide timely, unbiased, scientifically sound e...

Interventions for preventing silent cerebral infarcts in people with sickle cell disease

PubMed Central

Estcourt, Lise J; Fortin, Patricia M; Hopewell, Sally; Trivella, Marialena; Doree, Carolyn; Abboud, Miguel R

2017-01-01

This is the protocol for a review and there is no abstract. The objectives are as follows: To assess the effectiveness of red blood transfusions and hydroxyurea alone or in combination and HSCT to reduce or prevent SCI in people with SCD. PMID:28344510

Role of ABCB5 P-Glycoprotein in Breast Cancer Multidrug Resistance

DTIC Science & Technology

2005-09-01

Hydroxyurea Doxorubicin Porfiromycin Mechlorethamine Fluorodopan Mitomycin Cytarabine (araC) Dianhydrogalactitol Gemcitabine Thiotepa N-N-Dibenzyl-daunomycin...0.0196 Mitomycin 0.4173 0.0318 Cytarabine (araC) 0.4163 0.0288 Dianhydrogalactitol 0.4105 0.0354 Gemcitabine 0.4088 0.0302 Thiotepa 0.4015 0.0232

Blood transfusion for preventing primary and secondary stroke in people with sickle cell disease.

PubMed

Estcourt, Lise J; Fortin, Patricia M; Hopewell, Sally; Trivella, Marialena; Wang, Winfred C

2017-01-17

Sickle cell disease is one of the commonest severe monogenic disorders in the world, due to the inheritance of two abnormal haemoglobin (beta globin) genes. Sickle cell disease can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Stroke affects around 10% of children with sickle cell anaemia (HbSS). Chronic blood transfusions may reduce the risk of vaso-occlusion and stroke by diluting the proportion of sickled cells in the circulation.This is an update of a Cochrane Review first published in 2002, and last updated in 2013. To assess risks and benefits of chronic blood transfusion regimens in people with sickle cell disease for primary and secondary stroke prevention (excluding silent cerebral infarcts). We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to 04 April 2016.We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register: 25 April 2016. Randomised controlled trials comparing red blood cell transfusions as prophylaxis for stroke in people with sickle cell disease to alternative or standard treatment. There were no restrictions by outcomes examined, language or publication status. Two authors independently assessed trial eligibility and the risk of bias and extracted data. We included five trials (660 participants) published between 1998 and 2016. Four of these trials were terminated early. The vast majority of participants had the haemoglobin (Hb)SS form of sickle cell disease.Three trials compared regular red cell transfusions to standard care in primary prevention of stroke: two in children with no previous long-term transfusions; and one in children and adolescents on long-term transfusion.Two trials compared the drug hydroxyurea (hydroxycarbamide) and phlebotomy to long-term transfusions and iron chelation therapy: one in primary prevention (children); and one in secondary prevention (children and adolescents).The quality of the evidence was very low to moderate across different outcomes according to GRADE methodology. This was due to the trials being at a high risk of bias due to lack of blinding, indirectness and imprecise outcome estimates. Red cell transfusions versus standard care Children with no previous long-term transfusionsLong-term transfusions probably reduce the incidence of clinical stroke in children with a higher risk of stroke (abnormal transcranial doppler velocities or previous history of silent cerebral infarct), risk ratio 0.12 (95% confidence interval 0.03 to 0.49) (two trials, 326 participants), moderate quality evidence.Long-term transfusions may: reduce the incidence of other sickle cell disease-related complications (acute chest syndrome, risk ratio 0.24 (95% confidence interval 0.12 to 0.48)) (two trials, 326 participants); increase quality of life (difference estimate -0.54, 95% confidence interval -0.92 to -0.17) (one trial, 166 participants); but make little or no difference to IQ scores (least square mean: 1.7, standard error 95% confidence interval -1.1 to 4.4) (one trial, 166 participants), low quality evidence.We are very uncertain whether long-term transfusions: reduce the risk of transient ischaemic attacks, Peto odds ratio 0.13 (95% confidence interval 0.01 to 2.11) (two trials, 323 participants); have any effect on all-cause mortality, no deaths reported (two trials, 326 participants); or increase the risk of alloimmunisation, risk ratio 3.16 (95% confidence interval 0.18 to 57.17) (one trial, 121 participants), very low quality evidence. Children and adolescents with previous long-term transfusions (one trial, 79 participants)We are very uncertain whether continuing long-term transfusions reduces the incidence of: stroke, risk ratio 0.22 (95% confidence interval 0.01 to 4.35); or all-cause mortality, Peto odds ratio 8.00 (95% confidence interval 0.16 to 404.12), very low quality evidence.Several review outcomes were only reported in one trial arm (sickle cell disease-related complications, alloimmunisation, transient ischaemic attacks).The trial did not report neurological impairment, or quality of life. Hydroxyurea and phlebotomy versus red cell transfusions and chelationNeither trial reported on neurological impairment, alloimmunisation, or quality of life. Primary prevention, children (one trial, 121 participants)Switching to hydroxyurea and phlebotomy may have little or no effect on liver iron concentrations, mean difference -1.80 mg Fe/g dry-weight liver (95% confidence interval -5.16 to 1.56), low quality evidence.We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: risk of stroke (no strokes); all-cause mortality (no deaths); transient ischaemic attacks, risk ratio 1.02 (95% confidence interval 0.21 to 4.84); or other sickle cell disease-related complications (acute chest syndrome, risk ratio 2.03 (95% confidence interval 0.39 to 10.69)), very low quality evidence. Secondary prevention, children and adolescents (one trial, 133 participants)Switching to hydroxyurea and phlebotomy may: increase the risk of sickle cell disease-related serious adverse events, risk ratio 3.10 (95% confidence interval 1.42 to 6.75); but have little or no effect on median liver iron concentrations (hydroxyurea, 17.3 mg Fe/g dry-weight liver (interquartile range 10.0 to 30.6)); transfusion 17.3 mg Fe/g dry-weight liver (interquartile range 8.8 to 30.7), low quality evidence.We are very uncertain whether switching to hydroxyurea and phlebotomy: increases the risk of stroke, risk ratio 14.78 (95% confidence interval 0.86 to 253.66); or has any effect on all-cause mortality, Peto odds ratio 0.98 (95% confidence interval 0.06 to 15.92); or transient ischaemic attacks, risk ratio 0.66 (95% confidence interval 0.25 to 1.74), very low quality evidence. There is no evidence for managing adults, or children who do not have HbSS sickle cell disease.In children who are at higher risk of stroke and have not had previous long-term transfusions, there is moderate quality evidence that long-term red cell transfusions reduce the risk of stroke, and low quality evidence they also reduce the risk of other sickle cell disease-related complications.In primary and secondary prevention of stroke there is low quality evidence that switching to hydroxyurea with phlebotomy has little or no effect on the liver iron concentration.In secondary prevention of stroke there is low-quality evidence that switching to hydroxyurea with phlebotomy increases the risk of sickle cell disease-related events.All other evidence in this review is of very low quality.

Blood transfusion for preventing primary and secondary stroke in people with sickle cell disease

PubMed Central

Estcourt, Lise J; Fortin, Patricia M; Hopewell, Sally; Trivella, Marialena; Wang, Winfred C

2017-01-01

Background Sickle cell disease is one of the commonest severe monogenic disorders in the world, due to the inheritance of two abnormal haemoglobin (beta globin) genes. Sickle cell disease can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Stroke affects around 10% of children with sickle cell anaemia (HbSS). Chronic blood transfusions may reduce the risk of vaso-occlusion and stroke by diluting the proportion of sickled cells in the circulation. This is an update of a Cochrane Review first published in 2002, and last updated in 2013. Objectives To assess risks and benefits of chronic blood transfusion regimens in people with sickle cell disease for primary and secondary stroke prevention (excluding silent cerebral infarcts). Search methods We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to 04 April 2016. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register: 25 April 2016. Selection criteria Randomised controlled trials comparing red blood cell transfusions as prophylaxis for stroke in people with sickle cell disease to alternative or standard treatment. There were no restrictions by outcomes examined, language or publication status. Data collection and analysis Two authors independently assessed trial eligibility and the risk of bias and extracted data. Main results We included five trials (660 participants) published between 1998 and 2016. Four of these trials were terminated early. The vast majority of participants had the haemoglobin (Hb)SS form of sickle cell disease. Three trials compared regular red cell transfusions to standard care in primary prevention of stroke: two in children with no previous long-term transfusions; and one in children and adolescents on long-term transfusion. Two trials compared the drug hydroxyurea (hydroxycarbamide) and phlebotomy to long-term transfusions and iron chelation therapy: one in primary prevention (children); and one in secondary prevention (children and adolescents). The quality of the evidence was very low to moderate across different outcomes according to GRADE methodology. This was due to the trials being at a high risk of bias due to lack of blinding, indirectness and imprecise outcome estimates. Red cell transfusions versus standard care Children with no previous long-term transfusions Long-term transfusions probably reduce the incidence of clinical stroke in children with a higher risk of stroke (abnormal transcranial doppler velocities or previous history of silent cerebral infarct), risk ratio 0.12 (95% confidence interval 0.03 to 0.49) (two trials, 326 participants), moderate quality evidence. Long-term transfusions may: reduce the incidence of other sickle cell disease-related complications (acute chest syndrome, risk ratio 0.24 (95% confidence interval 0.12 to 0.48)) (two trials, 326 participants); increase quality of life (difference estimate -0.54, 95% confidence interval -0.92 to -0.17) (one trial, 166 participants); but make little or no difference to IQ scores (least square mean: 1.7, standard error 95% confidence interval -1.1 to 4.4) (one trial, 166 participants), low quality evidence. We are very uncertain whether long-term transfusions: reduce the risk of transient ischaemic attacks, Peto odds ratio 0.13 (95% confidence interval 0.01 to 2.11) (two trials, 323 participants); have any effect on all-cause mortality, no deaths reported (two trials, 326 participants); or increase the risk of alloimmunisation, risk ratio 3.16 (95% confidence interval 0.18 to 57.17) (one trial, 121 participants), very low quality evidence. Children and adolescents with previous long-term transfusions (one trial, 79 participants) We are very uncertain whether continuing long-term transfusions reduces the incidence of: stroke, risk ratio 0.22 (95% confidence interval 0.01 to 4.35); or all-cause mortality, Peto odds ratio 8.00 (95% confidence interval 0.16 to 404.12), very low quality evidence. Several review outcomes were only reported in one trial arm (sickle cell disease-related complications, alloimmunisation, transient ischaemic attacks). The trial did not report neurological impairment, or quality of life. Hydroxyurea and phlebotomy versus red cell transfusions and chelation Neither trial reported on neurological impairment, alloimmunisation, or quality of life. Primary prevention, children (one trial, 121 participants) Switching to hydroxyurea and phlebotomy may have little or no effect on liver iron concentrations, mean difference -1.80 mg Fe/g dry-weight liver (95% confidence interval -5.16 to 1.56), low quality evidence. We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: risk of stroke (no strokes); all-cause mortality (no deaths); transient ischaemic attacks, risk ratio 1.02 (95% confidence interval 0.21 to 4.84); or other sickle cell disease-related complications (acute chest syndrome, risk ratio 2.03 (95% confidence interval 0.39 to 10.69)), very low quality evidence. Secondary prevention, children and adolescents (one trial, 133 participants) Switching to hydroxyurea and phlebotomy may: increase the risk of sickle cell disease-related serious adverse events, risk ratio 3.10 (95% confidence interval 1.42 to 6.75); but have little or no effect on median liver iron concentrations (hydroxyurea, 17.3 mg Fe/g dry-weight liver (interquartile range 10.0 to 30.6)); transfusion 17.3 mg Fe/g dry-weight liver (interquartile range 8.8 to 30.7), low quality evidence. We are very uncertain whether switching to hydroxyurea and phlebotomy: increases the risk of stroke, risk ratio 14.78 (95% confidence interval 0.86 to 253.66); or has any effect on all-cause mortality, Peto odds ratio 0.98 (95% confidence interval 0.06 to 15.92); or transient ischaemic attacks, risk ratio 0.66 (95% confidence interval 0.25 to 1.74), very low quality evidence. Authors’ conclusions There is no evidence for managing adults, or children who do not have HbSS sickle cell disease. In children who are at higher risk of stroke and have not had previous long-term transfusions, there is moderate quality evidence that long-term red cell transfusions reduce the risk of stroke, and low quality evidence they also reduce the risk of other sickle cell disease-related complications. In primary and secondary prevention of stroke there is low quality evidence that switching to hydroxyurea with phlebotomy has little or no effect on the liver iron concentration. In secondary prevention of stroke there is low-quality evidence that switching to hydroxyurea with phlebotomy increases the risk of sickle cell disease-related events. All other evidence in this review is of very low quality. PMID:24226646

Hydrogen Treatment Protects against Cell Death and Senescence Induced by Oxidative Damage.

PubMed

Han, A Lum; Park, Seong-Hoon; Park, Mi Sung

2017-02-28

Hydrogen has potential for preventive and therapeutic applications as an antioxidant. However, micro- and macroparticles of hydrogen in water disappear easily over time. In order to eliminate reactive oxygen species (ROS) related with the aging process, we used functional water containing nanoparticle hydrogen. Nanoparticle hydrogen does not disappear easily and collapse under water after long periods of time. We used murine embryonic fibroblasts that were isolated from 12.5-day embryos of C57BL/6 mice. We investigated the ability of nanoparticle hydrogen in water to suppress hydroxyurea-induced ROS production, cytotoxicity, and the accumulation of β-galactosidase (an indicator of aging), and promote cell proliferation. The accumulation of β-galactosidase in the cytoplasm and the appearance of abnormal nuclei were inhibited by daily treatment of cells with hydrogen water. When the aging process was accelerated by hydroxyurea-induced oxidative stress, the effect of hydrogen water was even more remarkable. Thus, this study showed the antioxidant and anti-senescence effects of hydrogen water. Nanoparticle hydrogen water is potentially a potent anti-aging agent.

A Systematic Review of Known Mechanisms of Hydroxyurea-induced Foetal Haemoglobin for Treatment of Sickle Cell Disease

PubMed Central

Pule, Gift D.; Mowla, Shaheen; Novitzky, Nicolas; Wiysonge, Charles S.; Wonkam, Ambroise

2016-01-01

Aims To report on molecular mechanisms of foetal haemoglobin (HbF) induction by hydroxyurea (HU) for the treatment of Sickle Cell Disease (SCD). Study Design Systematic review. Results Studies have provided consistent associations between genomic variations in HbF-promoting loci and variable HbF level in response to HU. Numerous signal transduction pathways have been implicated, through the identification of key genomic variants in BCL11A, HBS1L-MYB, SAR1 or XmnI polymorphism that predispose the response to the treatment, and signal transduction pathways, that modulate γ-globin expression (cAMP/cGMP; Giα/JNK/Jun; methylation and microRNA). Three main molecular pathways have been reported: 1) Epigenetic modifications, transcriptional events and signalling pathways involved in HU-mediated response, 2) Signalling pathways involving HU-mediated response and 3) Post-transcriptional pathways (regulation by microRNAs). Conclusions The complete picture of HU-mediated mechanisms of HbF production in SCD remains elusive. Research on post-transcriptional mechanisms could lead to therapeutic targets that may minimize alterations to the cellular transcriptome. PMID:26327494

A systematic review of known mechanisms of hydroxyurea-induced fetal hemoglobin for treatment of sickle cell disease.

PubMed

Pule, Gift D; Mowla, Shaheen; Novitzky, Nicolas; Wiysonge, Charles S; Wonkam, Ambroise

2015-10-01

To report on molecular mechanisms of fetal hemoglobin (HbF) induction by hydroxyurea (HU) for the treatment of sickle cell disease. Systematic review. Studies have provided consistent associations between genomic variations in HbF-promoting loci and variable HbF level in response to HU. Numerous signal transduction pathways have been implicated, through the identification of key genomic variants in BCL11A, HBS1L-MYB, SAR1 or XmnI polymorphism that predispose the response to the treatment, and signal transduction pathways that modulate γ-globin expression (cAMP/cGMP; Giα/c-Jun N-terminal kinase/Jun; methylation and miRNA). Three main molecular pathways have been reported: i) Epigenetic modifications, transcriptional events and signaling pathways involved in HU-mediated response, ii) Signaling pathways involving HU-mediated response and iii) Post-transcriptional pathways (regulation by miRNAs). The complete picture of HU-mediated mechanisms of HbF production in Sickle Cell Disease remains elusive. Research on post-transcriptional mechanisms could lead to therapeutic targets that may minimize alterations to the cellular transcriptome.

HABIT, a Randomized Feasibility Trial to Increase Hydroxyurea Adherence, Suggests Improved Health-Related Quality of Life in Youths with Sickle Cell Disease.

PubMed

Smaldone, Arlene; Findley, Sally; Manwani, Deepa; Jia, Haomiao; Green, Nancy S

2018-06-01

To examine the effect of a community health worker (CHW) intervention, augmented by tailored text messages, on adherence to hydroxyurea therapy in youths with sickle cell disease, as well as on generic and disease-specific health-related quality of life (HrQL) and youth-parent self-management responsibility concordance. We conducted a 2-site randomized controlled feasibility study (Hydroxyurea Adherence for Personal Best in Sickle Cell Treatment [HABIT]) with 2:1 intervention allocation. Youths and parents participated as dyads. Intervention dyads received CHW visits and text message reminders. Data were analyzed using descriptive statistics, the Wilcoxon signed-rank test, and growth models adjusting for group assignment, time, and multiple comparisons. Changes in outcomes from 0 to 6 months were compared with their respective minimal clinically important differences. A total of 28 dyads (mean age of youths, 14.3 ± 2.6 years; 50% Hispanic) participated (18 in the intervention group, 10 in the control group), with 10.7% attrition. Accounting for group assignment, time, and multiple comparisons, at 6 months intervention youths reported improved generic HrQL total score (9.8 points; 95% CI, 0.4-19.2) and Emotions subscale score (15.0 points; 95% CI, 1.6-28.4); improved disease-specific subscale scores for Worry I (30.0 points; 95% CI, 8.5-51.5), Emotions (37.0 points, 95% CI, 9.4-64.5), and Communication I (17.8 points; 95% CI, 0.5-35.1); and 3-month dyad self-management responsibility concordance (3.5 points; 95% CI, -0.2 to 7.1). There were no differences in parent proxy-reported HrQL measures at 6 months. These findings add to research examining effects of behavioral interventions on HrQL outcomes in youths with sickle cell disease. ClinicalTrials.gov: NCT02029742. Copyright © 2018 Elsevier Inc. All rights reserved.

A phase 2 study of ruxolitinib, an oral JAK1 and JAK2 Inhibitor, in patients with advanced polycythemia vera who are refractory or intolerant to hydroxyurea.

PubMed

Verstovsek, Srdan; Passamonti, Francesco; Rambaldi, Alessandro; Barosi, Giovanni; Rosen, Peter J; Rumi, Elisa; Gattoni, Elisabetta; Pieri, Lisa; Guglielmelli, Paola; Elena, Chiara; He, Shui; Contel, Nancy; Mookerjee, Bijoyesh; Sandor, Victor; Cazzola, Mario; Kantarjian, Hagop M; Barbui, Tiziano; Vannucchi, Alessandro M

2014-02-15

Polycythemia vera (PV) is a myeloproliferative neoplasm associated with somatic gain-of-function mutations of Janus kinase-2 (JAK2). Therapeutic options are limited in patients with advanced disease. Ruxolitinib, an oral JAK1/JAK2 inhibitor, is active in preclinical models of PV. The long-term efficacy and safety of ruxolitinib in patients with advanced PV who are refractory or intolerant to hydroxyurea were studied in a phase 2 trial. Response was assessed using modified European LeukemiaNet criteria, which included a reduction in hematocrit to <45% without phlebotomy, resolution of palpable splenomegaly, normalization of white blood cell and platelet counts, and reduction in PV-associated symptoms. Thirty-four patients received ruxolitinib for a median of 152 weeks (range, 31 weeks-177 weeks) or 35.0 months (range, 7.1 months-40.7 months). Hematocrit <45% without phlebotomy was achieved in 97% of patients by week 24.Only 1 patient required a phlebotomy after week 4. Among patients with palpable splenomegaly at baseline, 44% and 63%, respectively, achieved nonpalpable spleen measurements at weeks 24 and 144. Clinically meaningful improvements in pruritus, night sweats, and bone pain were observed within 4 weeks of the initiation of therapy and maintained with continued treatment. Ruxolitinib treatment also reduced elevated levels of inflammatory cytokines and granulocyte activation. Thrombocytopenia and anemia were the most common adverse events.Thrombocytopenia of grade 3 or anemia of grade 3 (according to National Cancer Institute Common Terminology Criteria for Adverse Events,version 3.0) occurred in 3 patients each (9%) (1 patient had both) and were managed with dose modification. Ruxolitinib was generally well tolerated and provided rapid and durable clinical benefits in patients with advanced PV who were refractory or intolerant to hydroxyurea.

Where to Turn for Second-Line Cytoreduction After Hydroxyurea in Polycythemia Vera?

PubMed

Nazha, Aziz; Gerds, Aaron T

2016-04-01

The goals of therapy in patients with polycythemia vera (PV) are to improve disease-related symptoms, prevent the incidence or recurrence of thrombosis, and possibly delay or prevent the transformation into myelofibrosis or acute myeloid leukemia (AML). Cytoreductive therapies have been used in older patients and those with a history of thrombosis to achieve these goals. Hydroxyurea (HU) remains the first-line cytoreductive choice; however, up to one in four patients treated with HU over time will develop resistance or intolerance to HU. More importantly, patients who fail HU have a 5.6-fold increase in mortality and a 6.8-fold increase risk of transformation to myelofibrosis or AML; therefore, alternative therapies are needed for these patients. Interferon-α has been used in PV and has shown significant activity in achieving hematologic responses and decreasing JAK2 V617F mutation allele burden. JAK inhibition has also been investigated and recently garnered regulatory approval for this indication. In this review, we will discuss the current treatment options that are available for patients after HU and the novel therapies that are currently under investigation. The outcomes of PV patients who fail or who are intolerant of hydroxyurea are poor. Although pegylated interferon can be considered in younger patients, currently, ruxolitinib is the only U.S. Food and Drug Administration-approved agent in this setting, representing a viable option, leading to hematocrit control and a reduction in spleen size and constitutional symptoms. Although a small number of patients will achieve a molecular response with continuous treatment, the implications of such response on the clinical outcomes are still unknown. Patients whose disease is not adequately controlled with ruxolitinib, or who lose their response, can be treated with low-dose busulfan or pipobroman; however, they should be encouraged to participate in trials with novel therapies. ©AlphaMed Press.

Hydroxyurea prescription, availability and use for children with sickle cell disease in Italy: Results of a National Multicenter survey.

PubMed

Colombatti, Raffaella; Palazzi, Giovanni; Masera, Nicoletta; Notarangelo, Lucia Dora; Bonetti, Elisa; Samperi, Piera; Barone, Angelica; Perrotta, Silverio; Facchini, Elena; Miano, Maurizio; Del Vecchio, Giovanni Carlo; Guerzoni, Maria Elena; Corti, Paola; Menzato, Federica; Cesaro, Simone; Casale, Maddalena; Rigano, Paolo; Forni, Gian Luca; Russo, Giovanna; Sainati, Laura

2018-02-01

The number of patients with sickle cell disease (SCD) has increased in Italy in the past decade due to immigration. In spite of the established efficacy of hydroxyurea (HU) in childhood, population-based data regarding its prescription and effectiveness come mainly from studies performed in adults or outside Europe. The Hydroxyurea in SCD: A Large Nation-wide Cohort Study from Italy was a retrospective cohort study of adult and pediatric patients with SCD attending 32 centers. Pediatric data are analyzed separately. Out of 504 children followed in 11 centers, 206 (40%) were on HU (194 SS/Sβ°, 12 SC/Sß+); 74% came from Sub-Saharian Africa and 18% from Europe. HU therapy indications for SS/Sβ° patients were as follows: 57% painful vaso-occlusive crisis, acute chest syndrome or both, 24% anemia, 8% anemia, and other reasons (the majority had Hb ≤ 8-8.5 g/dl, revealing scarce acceptance of low Hb values by pediatric hematologist). Mean starting dose was 15.5 mg/kg, and dose at full regimen was 17.1 mg/kg. Mean age at HU therapy was 7.68 years, although it was lower for SS/Sβ° patients. Only 10% started HU before 3 years. In 92%, 500 mg capsule was used; in 6%, the galenic was used; and in 2%, 100 mg tablet was used. Significant reduction of clinical events and inpatients admissions, with improvement in hematological parameters, was observed for SS/Sβ° patients and a trend toward improvement for SC/Sß+ patients was also observed. HU effectiveness is demonstrated in a national cohort of children with SCD living in Italy, even at a lower dose than recommended, revealing good adherence to a treatment program by a socially vulnerable group of patients such as immigrants. © 2017 Wiley Periodicals, Inc.

Post-Doctoral Research Award

DTIC Science & Technology

1988-12-01

day old tadpoles have completed most of organogenesis and, therefore, are usually not susceptible to malformation . An exception is limb development...antagonistic response may have b.een the result of poorer absorption of hydroxyurea by the severly malformed embryos, as isoniazid had a much greater...Short-chain carboxylic acids showed concentration additive joint actionsfor induction of malformation . Combinations of DNA synthesis inhibitors

Interventions for chronic kidney disease in people with sickle cell disease

PubMed Central

Roy, Noemi BA; Fortin, Patricia M; Bull, Katherine R; Doree, Carolyn; Trivella, Marialena; Hopewell, Sally; Estcourt, Lise J

2017-01-01

This is the protocol for a review and there is no abstract. The objectives are as follows: To assess the effectiveness of any intervention in preventing or reducing kidney complications or CKD in people with SCD (including red blood cell transfusions, hydroxyurea and ACEI (either alone or in combination with each other)). PMID:28344511

Joint Actions of Developmental Toxicants.

DTIC Science & Technology

1991-06-01

antagonistic response may have been the result of poorer absorption of hydroxyurea by the severly malformed embryos, as isoniazid had a much greater...chain carboxylic acids showed concentration additive joint actions for induction of malformation . Combinations of DNA synthesis inhibitors showed...response additive to antagonistic joint actions at malformation -inducing con- centrations. Since each compound inhibits a different enzyme in the process of

Fetal hemoglobin in sickle cell anemia: The Arab-Indian haplotype and new therapeutic agents.

PubMed

Habara, Alawi H; Shaikho, Elmutaz M; Steinberg, Martin H

2017-11-01

Fetal hemoglobin (HbF) has well-known tempering effects on the symptoms of sickle cell disease and its levels vary among patients with different haplotypes of the sickle hemoglobin gene. Compared with sickle cell anemia haplotypes found in patients of African descent, HbF levels in Saudi and Indian patients with the Arab-Indian (AI) haplotype exceed that in any other haplotype by nearly twofold. Genetic association studies have identified some loci associated with high HbF in the AI haplotype but these observations require functional confirmation. Saudi patients with the Benin haplotype have HbF levels almost twice as high as African patients with this haplotype but this difference is unexplained. Hydroxyurea is still the only FDA approved drug for HbF induction in sickle cell disease. While most patients treated with hydroxyurea have an increase in HbF and some clinical improvement, 10 to 20% of adults show little response to this agent. We review the genetic basis of HbF regulation focusing on sickle cell anemia in Saudi Arabia and discuss new drugs that can induce increased levels of HbF. © 2017 Wiley Periodicals, Inc.

Fertility challenges for women with sickle cell disease.

PubMed

Ghafuri, Djamila L; Stimpson, Sarah-Jo; Day, Melissa E; James, Andra; DeBaun, Michael R; Sharma, Deva

2017-10-01

Sickle cell disease (SCD) represents one of the most common monogenic blood disorders worldwide, with an incidence of over 300,000 newborns affected per year. Reproductive challenges for men and women with SCD have been previously reviewed; however, evidence-based strategies to prevent and manage infertility and increase fecundity are lacking in women with SCD, which is one of the most important factors for quality of life. Areas covered: This review article summarizes the known risk factors for infertility, low fecundity, and premature menopause related to SCD. Expert commentary: Women with SCD have unique risk factors that may impact their ability to conceive, including chronic inflammation, oxidative stress, transfusion-related hemochromatosis, and ovarian sickling, causing ischemia and reperfusion injury to the ovary. Contraception is strongly recommended while on hydroxyurea therapy during reproductive years and discontinuing hydroxyurea for family planning and during pregnancy based on teratogenicity in animal studies. Hematopoietic stem cell transplantation (HSCT), the only curative therapy, sometimes involves conditioning regimens containing alkylating agents and total body irradiation that contribute to infertility and premature ovarian failure. Prior to HSCT or gene therapy, we strongly recommend referral to a reproductive endocrinologist to discuss fertility preservation and surrogacy options for all women with SCD.

MOF Suppresses Replication Stress and Contributes to Resolution of Stalled Replication Forks.

PubMed

Singh, Dharmendra Kumar; Pandita, Raj K; Singh, Mayank; Chakraborty, Sharmistha; Hambarde, Shashank; Ramnarain, Deepti; Charaka, Vijaya; Ahmed, Kazi Mokim; Hunt, Clayton R; Pandita, Tej K

2018-03-15

The human MOF (hMOF) protein belongs to the MYST family of histone acetyltransferases and plays a critical role in transcription and the DNA damage response. MOF is essential for cell proliferation; however, its role during replication and replicative stress is unknown. Here we demonstrate that cells depleted of MOF and under replicative stress induced by cisplatin, hydroxyurea, or camptothecin have reduced survival, a higher frequency of S-phase-specific chromosome damage, and increased R-loop formation. MOF depletion decreased replication fork speed and, when combined with replicative stress, also increased stalled replication forks as well as new origin firing. MOF interacted with PCNA, a key coordinator of replication and repair machinery at replication forks, and affected its ubiquitination and recruitment to the DNA damage site. Depletion of MOF, therefore, compromised the DNA damage repair response as evidenced by decreased Mre11, RPA70, Rad51, and PCNA focus formation, reduced DNA end resection, and decreased CHK1 phosphorylation in cells after exposure to hydroxyurea or cisplatin. These results support the argument that MOF plays an important role in suppressing replication stress induced by genotoxic agents at several stages during the DNA damage response. Copyright © 2018 American Society for Microbiology.

Prasugrel hydrochloride for the treatment of sickle cell disease.

PubMed

Conran, Nicola; Rees, David C

2017-07-01

Therapeutic options for sickle cell disease (SCD) are limited and, currently, only one drug (hydroxyurea) has FDA approval for the treatment of adult SCD. While this genetic disease is caused by hemoglobin polymerization, subsequent downstream events trigger platelet activation, vaso-occlusion and the disease's complex pathophysiology. Areas covered: The oral thienopyridine, prasugrel hydrochloride, irreversibly inhibits the P2Y12 receptors, inhibiting ADP-dependent platelet activation. We discuss recent clinical trials evaluating the pharmokinetics of prasugrel and its potential for use in SCD. Expert opinion: Prasugrel administration in SCD appears to be well tolerated and safe. However, although this drug modestly inhibits platelet activity in these patients, administration of prasugrel to a large group of children and adolescents for up to 24 months failed to convincingly reduce vaso-occlusive complications. Speculatively, prasugrel may be of occasional use for off-license purposes in patients unable or unwilling to take hydroxyurea (particularly in 12-17-year olds). Although there is currently no prospect of prasugrel being licensed for use in SCD, the success of on-going trials of other antiplatelet agents in SCD might lead to further trials of prasugrel in SCD.

Splanchnic vein thrombosis in myeloproliferative neoplasms: treatment algorithm 2018.

PubMed

Finazzi, Guido; De Stefano, Valerio; Barbui, Tiziano

2018-06-26

Myeloproliferative neoplasms (MPNs) are a leading cause of splanchnic vein thrombosis (SVT). SVT is observed in all MPNs and frequently affects young patients. Therapy should be addressed to three main goals: preventing thrombosis recurrence, managing the underlying MPN, and supporting liver dysfunction. Life-long oral anticoagulation with vitamin K antagonists is the cornerstone of the antithrombotic treatment. However, recurrences of SVT or other thrombosis may occur in 15-20% of patients. Direct oral anticoagulants can represent an alternative and preliminary data encourage comparative studies. Survival of patients with SVT in MPN is primarily influenced by the natural history of the underlying neoplasms, rather than the SVT event. An aggressive management is recommended and a treatment algorithm based on the different MPN subtypes is proposed. Hydroxyurea is the cytoreductive drug of choice in polycythemia vera and essential thrombocythemia, whereas ruxolitinib is indicated in intermediate and high-risk patients with myelofibrosis and in PV patients resistant or intolerant to hydroxyurea. The management of SVT in MPNs requires a multidisciplinary approach that may include a hematologist, a gastroenterologist, an interventional radiologist, and a surgeon. In the case of clinical deterioration despite pharmacological therapy, patients with SVT should be considered for invasive procedures or liver transplantation.

ESR studies on reactivity of protein-derived tyrosyl radicals formed by prostaglandin H synthase and ribonucleotide reductase.

PubMed

Lassmann, G; Curtis, J; Liermann, B; Mason, R P; Eling, T E

1993-01-01

Using ESR spectroscopy, the ability of enzyme inhibitors to quench protein-derived tyrosyl radicals was studied in two different enzymes, prostaglandin H synthase and ribonucleotide reductase. The prostaglandin H synthase inhibitors indomethacin, eugenol, and MK-410 effectively prevent the formation of tyrosyl radicals during the oxidation of arachidonic acid by prostaglandin H synthase from ram seminal vesicles. A direct reaction with preformed tyrosyl radicals was observed only with eugenol. The other prostaglandin H synthase inhibitors were ineffective. The ribonucleotide reductase inhibitors hydroxyurea and 4-hydroxyanisole, which effectively inactivate the tyrosyl radical in the active site of ribonucleotide reductase present in tumor cells, exhibit a different reactivity with tyrosyl radicals formed by prostaglandin H synthase. Hydroxyurea quenches preformed tyrosyl radicals in prostaglandin H synthase weakly, whereas 4-hydroxyanisole does not quench tyrosyl radicals in prostaglandin H synthase at all. Eugenol, which quenches preformed prostaglandin H synthase-derived tyrosyl radicals, also quenches the tyrosyl radical in ribonucleotide reductase. The results suggest that the reactivity of protein-linked tyrosyl radicals in ribonucleotide reductase and those formed during prostaglandin H synthase catalysis are very different and have unrelated roles in enzyme catalysis.

Inpatient management of sickle cell pain: a 'snapshot' of current practice.

PubMed

Miller, Scott T; Kim, Hae-Young; Weiner, Debra; Wager, Carrie G; Gallagher, Dianne; Styles, Lori; Dampier, Carlton D

2012-03-01

The Sickle Cell Disease Clinical Research Network (SCDCRN) designed the PROACTIVE Feasibility Study (ClinicalTrials.gov NCT00951808) to determine whether elevated serum levels of secretory phospholipase A2 (sPLA2) during hospitalization for pain would permit preemptive therapy of sickle cell acute chest syndrome (ACS) by blood transfusion. While PROACTIVE was not designed to assess pain management and was terminated early due to inadequate patient accrual, collection of clinical data allowed a "snapshot" of current care by expert providers. Nearly half the patients admitted for pain were taking hydroxyurea; hydroxyurea did not affect length of stay. Providers commonly administered parenteral opioid analgesia, usually morphine or hydromorphone, to adults and children, generally by patient-controlled analgesia (PCA). Adult providers were more likely to prescribe hydromorphone and did so at substantially higher morphine equivalent doses than were given to adults receiving morphine; the latter received doses similar to children who received either medication. All subjects treated with PCA received higher daily doses of opioids than those treated by time-contingent dosing. Physicians often restricted intravenous fluids to less than a maintenance rate and underutilized incentive spirometry, which reduces ACS in patients hospitalized for pain.

Inpatient Management of Sickle Cell Pain: a Snapshot of Current Practice

PubMed Central

Miller, Scott T.; Kim, Hae-Young; Weiner, Debra; Wager, Carrie G.; Gallagher, Dianne; Styles, Lori; Dampier, Carlton D.

2012-01-01

The Sickle Cell Disease Clinical Research Network (SCDCRN) designed the PROACTIVE Feasibility Study (ClinicalTrials.gov NCT00951808) to determine whether elevated serum levels of secretory phospholipase A2 (sPLA2) during hospitalization for pain would permit preemptive therapy of sickle cell acute chest syndrome (ACS) by blood transfusion. [1, 2] While PROACTIVE was not designed to assess pain management and terminated early due to inadequate patient accrual, collection of clinical data allowed a “snapshot” of current care by expert providers. Nearly half the patients admitted for pain were taking hydroxyurea; hydroxyurea did not affect length of stay. Providers commonly administered parenteral opioid analgesia, usually morphine or hydromorphone, to adults and children, generally by patient-controlled analgesia (PCA). Adult providers were more likely to prescribe hydromorphone and did so at substantially higher morphine equivalent doses than were given to adults receiving morphine; the latter received doses similar to children who received either medication. All subjects treated with PCA received higher daily doses of opioids than those treated by time-contingent dosing. Physicians often restricted intravenous fluids to less than a maintenance rate and underutilized incentive spirometry, which reduces ACS in patients hospitalized for pain. [3] PMID:22231150

Ribonucleotide Reductase Inhibitors Reduce Atherosclerosis in a Double-Injury Rabbit Model

PubMed Central

Gallaugher, Laura D; Henry, Jon C; Kearns, Patrick N; Elford, Howard L; Bergdall, Valerie K; Cardounel, Arturo J

2009-01-01

Atheroproliferative disorders such as atherosclerosis are an important health problem and one of the leading causes of morbidity and mortality in the United States. Minimally invasive therapeutic procedures, including angioplasty with stent deployment, are used frequently for obstructive coronary artery disease. However, restenosis, a proliferative vascular response, is a common sequela to this procedure. The current study investigated the effect of inhibiting ribonucleotide reductase (RR), an enzyme necessary for cellular proliferation, in an attempt to ameliorate the proliferative response. Two RR inhibitors, didox and hydroxyurea, were chosen for their potent antiproliferative properties. Studies were carried out by using a double-injury rabbit model, in which endothelial denudation was followed by the administration of a high-fat diet. At 4 wk after initial endothelial denudation, the developing atherosclerotic lesion was subjected to transluminal balloon dilation to simulate clinical intervention with percutaneous transluminal angioplasty. The degree of restenosis and atheroproliferation was assessed at 8 wk. Histologic evaluation of the lesion demonstrated that treatment with didox and hydroxyurea significantly decreased lesion area and lumen loss. These results suggest that RR inhibition may be an effective new tool for the treatment of atheroproliferative disorders. PMID:20034432

An exceptional case of renal artery restenosis in a patient with polycythaemia vera.

PubMed

Gavriilaki, Eleni; Sampanis, Nikolaos; Kavlakoudis, Christos; Papaioannou, George; Vasileiou, Sotirios

2014-12-01

Polycythaemia vera represents a rare chronic myeloproliferative neoplasm characterized by an increased thrombotic risk. Previous case reports have documented a link between primary or secondary polycythemia and the presence of renal artery stenosis and renovascular hypertension. Herein, we report an exceptional case of renal artery restenosis leading to uncontrolled hypertension in a patient with PV and high haematocrit levels. A 52-year-old female patient with a history of polycythaemia vera under treatment with hydroxyurea and phlebotomy presented in our outpatient clinic with newly diagnosed hypertension caused by left renal artery stenosis. Six months after stenting, patient returned for a follow-up visit due to uncontrolled hypertension and high haematocrit levels. Total restenosis of the left renal artery was found. Patient received optical medical treatment and was prescribed to higher doses of hydroxyurea by her treating haematologist. Since then, blood pressure and Hct levels remain adequately controlled. As described by earlier case reports, renal artery stenosis, hypertension and polycythemia often coexist. However, renovascular hypertension may not only lead to secondary erythrocytosis but also be a thrombotic complication of primary erythrocytosis. Thus, patients with polycythaemia vera should be carefully evaluated and optimally managed when hypertension or impaired renal function coexist.

Cytoplasmic localization of Hug1p, a negative regulator of the MEC1 pathway, coincides with the compartmentalization of Rnr2p–Rnr4p

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ainsworth, William B.; Hughes, Bridget Todd; Au, Wei Chun

2013-10-04

Highlights: •Hug1p overexpression sensitizes wild-type cells to DNA damage and hydroxyurea (HU). •Expression of Hug1p in response to HU treatment is delayed relative to Rnr3p. •MEC1 pathway genes are required for cytoplasmic localization of Hug1p. •Hug1p subcellular compartmentalization to the cytoplasm coincides with Rnr2p–Rnr4p. -- Abstract: The evolutionarily conserved MEC1 checkpoint pathway mediates cell cycle arrest and induction of genes including the RNR (Ribonucleotide reductase) genes and HUG1 (Hydroxyurea, ultraviolet, and gamma radiation) in response to DNA damage and replication arrest. Rnr complex activity is in part controlled by cytoplasmic localization of the Rnr2p–Rnr4p subunits and inactivation of negative regulatorsmore » Sml1p and Dif1p upon DNA damage and hydroxyurea (HU) treatment. We previously showed that a deletion of HUG1 rescues lethality of mec1Δ and suppresses dun1Δ strains. In this study, multiple approaches demonstrate the regulatory response of Hug1p to DNA damage and HU treatment and support its role as a negative effector of the MEC1 pathway. Consistent with our hypothesis, wild-type cells are sensitive to DNA damage and HU when HUG1 is overexpressed. A Hug1 polyclonal antiserum reveals that HUG1 encodes a protein in budding yeast and its MEC1-dependent expression is delayed compared to the rapid induction of Rnr3p in response to HU treatment. Cell biology and subcellular fractionation experiments show localization of Hug1p-GFP to the cytoplasm upon HU treatment. The cytoplasmic localization of Hug1p-GFP is dependent on MEC1 pathway genes and coincides with the cytoplasmic localization of Rnr2p–Rnr4p. Taken together, the genetic interactions, gene expression, and localization studies support a novel role for Hug1p as a negative regulator of the MEC1 checkpoint response through its compartmentalization with Rnr2p–Rnr4p.« less

Serum Paraoxonase Activity and Malondialdehyde Serum Concentrations Remain Unaffected in Response to Hydroxyurea Therapy in β-Thalassemia Patients.

PubMed

Zohaib, Muhammad; Ansari, Saqib H; Hashim, Zehra; Shamsi, Tahir S; Zarina, Shamshad

2016-07-01

β-Thalassemia is the most common hereditary disorder characterized by reduced production of β-globin chains of hemoglobin A (HbA). In recent years, hydroxyurea (HU) has shown promising therapeutic benefits in patients with β-thalassemia by fetal hemoglobin augmentation. We have analyzed effects of hydroxyurea treatment on oxidative stress in β-thalassemia patients by assessing activities of paraoxonase (PON) and arylesterase along with malondialdehyde (MDA) and total reactive oxygen species (ROS) concentrations. Blood samples from 159 individuals including 56 HU-treated and 58 untreated β-thalassemia patients and 45 healthy controls were analyzed. PON activity was found to be highest in healthy individuals (177.76 ± 4.44 U/mL) as compared to treated (52.67 ± 3.65 U/mL) and untreated (55.11 ± 3.26 U/mL) patients. A similar trend was observed in the case of arylesterase activity in normal, β-thalassemia-treated, and untreated (210.0 ± 11.25 U/mL, 163.03 ± 9.04 U/mL, 139.77 ± 10.10 U/mL) subjects. Serum MDA concentrations (2.59 ± 0.09 nmol/mL, 2.45 ± 0.08 nmol/mL, and 1.15 ± 0.05 nmol/mL) and total ROS concentrations (3.73 ± 0.20 nmol/mL, 3.54 ± 0.23 nmol/mL, and 2.45 ± 0.14 nmol/mL) were significantly elevated in both groups (untreated and treated) as compared to healthy individuals (P < .01). Oxidative stress was found to be markedly elevated in β-thalassemia patients as compared to healthy controls. Insignificant differences were, however, observed in mean concentrations of PON1 paraoxonase and arylesterase activities, serum MDA concentration and total ROS concentrations between HU-treated and untreated patients. We propose that HU therapy alone seems to be ineffective in managing oxidative stress and is likely to offer a better clinical outcome when supplemented with efficient iron chelation therapy and antioxidants. © 2015, The American College of Clinical Pharmacology.

X-ray-related potentially lethal damage expressed by chromosome condensation and the influence of caffeine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasaki, H.; Nishimoto, T.

1989-10-01

Caffeine has been reported to induce premature chromosome condensation (PCC) in S-phase cells in the presence of an inhibitor of DNA synthesis. We found that when S-phase cells are treated with caffeine and hydroxyurea after X irradiation, substantially more potentially lethal damage (PLD) is expressed, but the addition of cycloheximide, which inhibits PCC induction in S-phase cells, in the presence of caffeine and hydroxyurea reduces the expression of PLD to the same level as seen with caffeine alone. This can be interpreted to mean that the expression of PLD seen with caffeine in the absence of an inhibitor of DNAmore » synthesis is not associated with chromosome condensation. Evidence that PCC induction in S-phase cells and the influence of caffeine on PLD expression were suppressed by incubation at 40 degrees C of tsBN75 cells with a ts defect in ubiquitin-activating enzyme indicates the involvement of ubiquitin in these two processes. These observations as well as previous findings on ubiquitin suggest to us that caffeine induces changes in DNA-chromatin conformation, which are caused by induction of PCC or ubiquitination of chromosomal protein. Such changes occurring postirradiation would favor expression of PLD.« less

Hydroxyurea-mediated neuroblast ablation establishes birthdates of secondary lineages and addresses neuronal interactions in the developing Drosophila brain

PubMed Central

Lovick, Jennifer K.; Hartenstein, Volker

2015-01-01

The Drosophila brain is comprised of neurons formed by approximately 100 lineages, each of which is derived from a stereotyped, asymmetrically dividing neuroblast. Lineages serve as structural and developmental units of Drosophila brain anatomy and reconstruction of lineage projection patterns represents a suitable map of Drosophila brain circuitry at the level of neuron populations (“macro-circuitry”). Two phases of neuroblast proliferation, the first in the embryo and the second during the larval phase (following a period of mitotic quiescence), produce primary and secondary lineages, respectively. Using temporally controlled pulses of hydroxyurea (HU) to ablate neuroblasts and their corresponding secondary lineages during the larval phase, we analyzed the effect on development of primary and secondary lineages in the late larval and adult brain. Our findings indicate that timing of neuroblast re-activation is highly stereotyped, allowing us to establish “birth dates” for all secondary lineages. Furthermore, our results demonstrate that, whereas the trajectory and projection pattern of primary and secondary lineages is established in a largely independent manner, the final branching pattern of secondary neurons is dependent upon the presence of appropriate neuronal targets. Taken together, our data provide new insights into the degree of neuronal plasticity during Drosophila brain development. PMID:25773365

Molecular structure, vibrational spectra and quantum chemical MP2/DFT studies toward the rational design of hydroxyurea imprinted polymer

NASA Astrophysics Data System (ADS)

Prasad, Bhim Bali; Rai, Garima

2013-03-01

In this study, both experimental and theoretical vibrational spectra of template (hydroxyurea, HU), monomer (N-(4,6-bisacryloyl amino-[1,3,5] triazine-2-yl-)-acryl amide, TAT), and HU-TAT complexes were compared and these were respectively found to be in good agreement. Binding energies of HU, when complexed with different monomers, were computed using second order Moller Plesset theory (MP2) at 6-311++G(d,p) level both in the gas as well as solution phases. HU is an antineoplastic agent extensively being used in the treatment of polycythaemia Vera and thrombocythemia. It is also used to reduce the frequency of painful attacks in sickle cell anemia. It has antiretroviral property in disease like AIDS. All spectral characterizations were made using Density Functional Theory (DFT) at B3LYP employing 6-31+g(2d, 2p) basis set. The theoretical values for 13C and 1H NMR chemical shifts were found to be in accordance with the corresponding experimental values. Of all different monomers studied for the synthesis of molecularly imprinted polymer (MIP) systems, the monomer TAT (2 mol) was typically found to have a best binding score requisite for complexation with HU (1 mol) at the ground state.

Blood mononuclear cell gene expression profiles characterize the oxidant, hemolytic, and inflammatory stress of sickle cell disease

PubMed Central

Jison, Maria L.; Munson, Peter J.; Barb, Jennifer J.; Suffredini, Anthony F.; Talwar, Shefali; Logun, Carolea; Raghavachari, Nalini; Beigel, John H.; Shelhamer, James H.; Danner, Robert L.; Gladwin, Mark T.

2016-01-01

In sickle cell disease, deoxygenation of intra-erythrocytic hemoglobin S leads to hemoglobin polymerization, erythrocyte rigidity, hemolysis, and microvascular occlusion. Ischemia-reperfusion injury, plasma hemoglobin-mediated nitric oxide consumption, and free radical generation activate systemic inflammatory responses. To characterize the role of circulating leukocytes in sickle cell pathogenesis we performed global transcriptional analysis of blood mononuclear cells from 27 patients in steady-state sickle cell disease (10 patients treated and 17 patients untreated with hydroxyurea) compared with 13 control subjects. We used gender-specific gene expression to validate human microarray experiments. Patients with sickle cell disease demonstrated differential gene expression of 112 genes involved in heme metabolism, cell-cycle regulation, antioxidant and stress responses, inflammation, and angiogenesis. Inducible heme oxygenase-1 and downstream proteins biliverdin reductase and p21, a cyclin-dependent kinase, were up-regulated, potentially contributing to phenotypic heterogeneity and absence of atherosclerosis in patients with sickle cell disease despite endothelial dysfunction and vascular inflammation. Hydroxyurea therapy did not significantly affect leukocyte gene expression, suggesting that such therapy has limited direct anti-inflammatory activity beyond leukoreduction. Global transcriptional analysis of circulating leukocytes highlights the intense oxidant and inflammatory nature of steady-state sickle cell disease and provides insight into the broad compensatory responses to vascular injury. PMID:15031206

Relationship Between Some Single-nucleotide Polymorphism and Response to Hydroxyurea Therapy in Iranian Patients With β-Thalassemia Intermedia.

PubMed

Karimi, Mehran; Zarei, Tahereh; Haghpanah, Sezaneh; Moghadam, Mohamad; Ebrahimi, Ahmad; Rezaei, Narges; Heidari, Ghazaleh; Vazin, Afsaneh; Khavari, Maryam; Miri, Hamid R

2017-05-01

To evaluate the possible relationship between hydroxyurea (HU) response and some single-nucleotide polymorphism (SNP) in patients affected by β-thalassemia intermedia. In this cross-sectional study, 100 β-thalassemia intermedia patients who were taking HU with a dose of 8 to 15 mg/kg body weight per day for a period of at least 6 months were randomly selected between February 2013 and October 2014 in southern Iran. HU response was defined based on decrease or cessation of the blood transfusion need and evaluation of Hb level. In univariate analysis, from all evaluated SNPs, only rs10837814 SNP of olfactory receptors (ORs) OR51B2 showed a significant association with HU response (P=0.038) and from laboratory characteristics, only nucleated red blood cells showed significant associations (116%±183%) in good responders versus (264%±286%) in poor responders (P=0.045). In multiple logistic regression, neither laboratory variables nor different SNPs, showed significant association with HU response. Three novel nucleotide variations (-665 [A→C], -1301 [T→G],-1199 delA) in OR51B2 gene were found in good responders. None of the evaluated SNPs in our study showed significant association with HU response. Further larger studies and evaluation of other genes are suggested.

Quantification of hydroxyurea in human plasma by HPLC-MS/MS and its application to pharmacokinetics in patients with chronic myeloid leukaemia.

PubMed

Hai, Xin; Guo, Meihua; Gao, Chunlu; Zhou, Jin

2017-04-15

Hydroxyurea (HU) has been used in the treatment of chronic myeloid leukaemia (CML) and other myeloproliferative malignancies. Considering patient's wide variation in clinical response to HU, a new and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to monitor patients' compliance to treatment and investigate the pharmacokinetics of HU in patients with CML. Stable isotope labeled HU- 13 C 1 , 15 N 2 was used as internal standard. Plasma samples were treated with acetonitrile to precipitate protein. The supernatant was injected directly without derivatization and separated on a hydrophilic interaction liquid chromatography column. HU was quantitatively analyzed with a mobile phase of acetonitrile-1.5mM ammonium formate (90:10, V:V) within 3min. The proposed method provided a linearity range of 1-200μg/mL. The coefficients of variation for intra- and inter-day precision were less than 2.07% and 4.28%, respectively, while the accuracy (bias) was in the range of -3.77 to 2.96%. This method was satisfactorily applied to the determination of HU in two patients with CML. It is suitable for supporting pharmacokinetic studies and clinical therapeutic monitoring. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of hydroxyurea in human plasma by HPLC-UV using derivatization with xanthydrol.

PubMed

Legrand, Tiphaine; Rakotoson, Marie-Georgine; Galactéros, Frédéric; Bartolucci, Pablo; Hulin, Anne

2017-10-01

A simple and rapid high performance liquid chromatography (HPLC) method using ultraviolet (UV) detection was developed to determine hydroxyurea (HU) concentration in plasma sample after derivatization with xanthydrol. Two hundred microliters samples were spiked with methylurea (MeU) as internal standard and proteins were precipitated by adding methanol. Derivatization of HU and MeU was immediately performed by adding 0.02M xanthydrol and 1.5M HCl in order to obtain xanthyl-derivatives of HU and MeU that can be further separated using HPLC and quantified using UV detection at 240nm. Separation was achieved using a C18 column with a mobile phase composed of 20mM ammonium acetate and acetonitrile in gradient elution mode at a flow rate of 1mL/min. The total analysis time did not exceed 18min. The method was found linear from 5 to 400μM and all validation parameters fulfilled the international requirements. Between- and within-run accuracy error ranged from -4.7% to 3.2% and precision was lower than 12.8%. This simple method requires small volume samples and can be easily implemented in most clinical laboratories to develop pharmacokinetics studies of HU and to promote its therapeutic monitoring. Copyright © 2017 Elsevier B.V. All rights reserved.

Hydroxyurea for hemoglobin E/β-thalassemia: a systematic review and meta-analysis.

PubMed

Algiraigri, Ali H; Kassam, Aliya

2017-12-01

Hemoglobin E-beta thalassemia (Hb E/β-thalassemia) is a distinct, yet common, type of β-thalassemia, in which the patient co-inherits a β-thalassemia allele from one parent, and a structural variant, Hb E, from the other parent. This co-inheritance leads to remarkable clinical heterogeneity, varying degrees of chronic anemia, and a wide spectrum of complications due to ineffective erythropoiesis and iron overload. Hydroxyurea (HU), an oral chemotherapeutic drug, is expected to decrease disease severity. To assess the clinical efficacy and safety of HU in Hb E/β-thalassemia patients. We searched MEDLINE, EMBASE, Cochrane databases, and major preceding conferences for studies that assessed HU in Hb E/β-thalassemias patients. The effect size was estimated as a proportion (responder/sample size). Qualities of eligible studies were assessed using NIH tools. A total of five [one randomized clinical trial (RCT) and four observational] studies involving 106 patients were included. HU was associated with a significant RR of 46% with no statistical heterogeneity. No serious adverse effects were reported. Patients with Hb E/β-thalassemia may benefit from a trial of HU, though large RCTs assessing efficacy should be conducted to confirm the findings of this meta-analysis and to assess long-term toxicity and response sustainability.

A high-yield procedure for isolation of metaphase chromosomes from root tips of Vicia faba L.

PubMed

Doležel, J; Cíhalíková, J; Lucretti, S

1992-08-01

A new method is described for the isolation of large quantities of Vicia faba metaphase chromosomes. Roots were treated with 2.5 mM hydroxyurea for 18 h to accumulate meristem tip cells at the G1/S interface. After release from the block, the cells re-entered the cell cycle with a high degree of synchrony. A treatment with 2.5 μM amiprophos-methyl (APM) was used to accumulate mitotic cells in metaphase. The highest metaphase index (53.9%) was achieved when, 6 h after the release from the hydroxyurea block, the roots were exposed to APM for 4 h. The chromosomes were released from formaldehyde-fixed root tips by chopping with a scalpel in LB01 lysis buffer. Both the quality and the quantity of isolated chromosomes, examined microscopically and by flow cytometry, depended on the extent of the fixation. The best results were achieved after fixation with 6% formaldehyde for 30 min. Under these conditions, 1 · 10(6) chromosomes were routinely obtained from 30 root tips. The chromosomes were morphologically intact and suitable both for high-resolution chromosome studies and for flow-cytometric analysis and sorting. After the addition of hexylene glycol, the chromosome suspensions could be stored at 4° C for six months without any signs of deterioration.

SB202190 affects cell response to hydroxyurea-induced genotoxic stress in root meristems of Vicia faba.

PubMed

Winnicki, Konrad; Maszewski, Janusz

2012-11-01

Genotoxic stress caused by a variety of chemical and physical agents may lead to DNA breaks and genome instability. Response to DNA damage depends on ATM/ATR sensor kinases and their downstream proteins, which arrange cell cycle checkpoints. Activation of ATM (ataxia-telangiectasia-mutated)/ATR (ATM and Rad 3-related) signaling pathway triggers cell cycle arrest (by keeping cyclin-Cdk complexes inactive), combined with gamma-phosphorylation of histone H2A.X and induction of DNA repair processes. However, genotoxic stress activates also mitogen-activated protein kinases (MAPKs) which may control the functions of checkpoint proteins both directly, by post-translational modifications, or indirectly, by regulation of their expression. Our results indicate that in root meristem cells of Vicia faba, MAP kinase signaling pathway takes part in response to hydroxyurea-induced genotoxic stress. It is shown that SB202190, an inhibitor of p38 MAP kinase, triggers PCC (premature chromosome condensation) more rapidly, but only if cell cycle checkpoints are alleviated by caffeine. Since SB202190 and, independently, caffeine reduces HU-mediated histone H4 Lys5 acetylation, it may be that there is a cooperation of MAP kinase signaling pathways and ATM/ATR-dependent checkpoints during response to genotoxic stress. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Adherence to hydroxyurea medication by children with sickle cell disease (SCD) using an electronic device: a feasibility study.

PubMed

Inoue, Susumu; Kodjebacheva, Gergana; Scherrer, Tammy; Rice, Gary; Grigorian, Matthew; Blankenship, Jeremy; Onwuzurike, Nkechi

2016-08-01

Adherence to hydroxyurea (HU) is a significant modifying factor in sickle cell vaso-occlusive pain. We conducted a study using an electronic medication container-monitor-reminder device (GlowCap™) to track adherence and determine whether use of this device affected rates of HU adherence. Subjects were regular attendees to our clinic. They were given a 37-item questionnaire and were asked to use a GlowCap containing HU. When the device cap is opened, it makes a remote "medication taken" record. The device also provides usage reminder in the form of lights and alarm sounds if the cap opening is delayed. Nineteen subjects participated in the survey, and 17 in the intervention phase. Of the 17, 12 had reliable adherence data. Seventeen caregivers of patients and two patients completed the survey. Two most common barriers to adherence identified were lack of reminders and absence of medicine home delivery. The intervention component of this study, which used both the electronic (GlowCap) method and medication possession ratio showed that the median adherence rate for the 12 patients evaluated was 85 %. The GlowCap device accurately kept a record of adherence rates. This device may be an effective tool for increasing HU medication adherence.

Investigation on the ZBG-functionality of phenyl-4-yl-acrylohydroxamic acid derivatives as histone deacetylase inhibitors.

PubMed

Musso, Loana; Cincinelli, Raffaella; Zuco, Valentina; Zunino, Franco; Nurisso, Alessandra; Cuendet, Muriel; Giannini, Giuseppe; Vesci, Loredana; Pisano, Claudio; Dallavalle, Sabrina

2015-10-15

A series of alternative Zn-binding groups were explored in the design of phenyl-4-yl-acrylohydroxamic acid derivatives as histone deacetylase (HDAC) inhibitors. Most of the synthesized compounds were less effective than the parent hydroxamic acid. However, the profile of activity shown by the analog bearing a hydroxyurea head group, makes this derivative promising for further investigation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Coagulation profile of Sudanese children with homozygous sickle cell disease and the effect of treatment with omega-3 fatty acid on the coagulation parameters.

PubMed

Awoda, Shiekh; Daak, Ahmed A; Husain, Nazik Elmalaika; Ghebremeskel, Kebreab; Elbashir, Mustafa I

2017-01-01

It has been reported that patients with SCD do have an abnormal coagulation profile. Coagulopathy is thought to be one of the key factors that contribute to the vaso-occlusive crisis that characterises sickle cell disease (SCD). In this study, we investigated whether Sudanese sickle cell patients have an abnormal coagulation profile. In addition, the effect of treatment with either omega-3 fatty acids or hydroxyurea on coagulation profile was assessed. Homozygous SCD patients untreated ( n  = 52), omega-3 treated ( n  = 44), hydroxyurea (HU) treated ( n  = 8) and healthy (HbAA) controls ( n  = 52) matched for age (4-20 years), gender and socioeconomic status were enrolled. Patients on omega-3 fatty acids, according to age, received one to four capsules containing 277.8 mg DHA and 39.0 mg eicosapentnoic. Patients on Hydroxyurea were in on dosage more than 20 mg/kg/day. The steady state levels of the coagulation parameters and the effect of the treatments with either HU or omega-3 fatty acids on markers of coagulation were investigated. Compared to the healthy controls, treated and untreated HbSS patients had lower hemoglobin, plasma Protein C, proteins S and higher white blood cell count (WBC), platelets count (PLTs) and plasma D-dimer levels,( p  < 0.05). In comparison to untreated HbSS, treatment with neither omega-3 nor HU had effect on the WBC, plasma proteins C and S, ( p  > 0.05). HU treated group had a lower PLTs count compared to HbSS untreated group ( p  < 0.5). The prothrombin and activated partial thromboplastin times and international normalized ratio (INR) of untreated patients are significantly higher than n-3 treated, HU-treated patients and health controls, ( p  < 0.05). Patients treated with omega-3 had lowered D-dimer levels in comparison to HU-treated and untreated HbSS patients, ( p  < 0.001). This study provides evidence that Sudanes patients have abnormal coagulation profile and treatment with either HU or omega-3 fatty acids might partially ameliorate SCD-associated chronic coagulopathic state.

Pain management trend of vaso-occulsive crisis (VOC) at a community hospital emergency department (ED) for patients with sickle cell disease.

PubMed

Inoue, Susumu; Khan, Isra'a; Mushtaq, Rao; Sanikommu, Srinivasa Reddy; Mbeumo, Carline; LaChance, Jenny; Roebuck, Michael

2016-01-01

Pain management at the emergency department (ED) for vaso-occulsive crisis (VOC) for patients with sickle cell disease has not been optimum, with a long delay in giving the initial analgesic. We conducted a retrospective survey over a 7-year period to determine our ED's timing in giving pain medication to patients with VOC as a quality improvement project. We compared different periods, children vs adults, and the influence of gender in the analgesic administration timing. This is a retrospective chart review of three different periods: (1) years 2007-2008, (2) years 2011-2012, and (3) year 2013. We extracted relevant information from ED records. Data were analyzed using Student t test, chi-square analysis, and the Kruskal-Wallis test. There was a progressive improvement in the time interval to the 1st analgesic over these three periods. Children received analgesics more quickly than adults in all periods. Male adult patients received pain medication faster than female adult patients, although initial pain scores were higher in female than in male patients. Progressively fewer pediatric patients utilized ED over these three periods, but no difference for adult patients was observed. The proportion of pediatric patients admitted to the hospital increased with each period. The progressive decrease in both the number of patients and the number of visits to the ED by children suggested that the collective number of VOC in children has decreased, possibly secondary to the dissemination of hydroxyurea use. We failed to observe the same trend in adult patients. The need for IV access, and ordering laboratory tests or imaging studies tends to delay analgesic administration. Delay in administration of the first analgesic was more pronounced for female adult patients than male adult patients in spite of their higher pain score. Health care providers working in ED should make conscious efforts to respect pain in women as well as pain in men. Though not proven from this study, we believe that a significantly wider use of hydroxyurea by adult patients most likely would reduce their utilization of ED for the purpose of relief of pain, and further pediatric hematologists may be better positioned to increase hydroxyurea adherence by young adult patients, since they have had established rapport with them before transitioning to adult care.

Changes in quality of life and disease-related symptoms in patients with polycythemia vera receiving ruxolitinib or standard therapy.

PubMed

Mesa, Ruben; Verstovsek, Srdan; Kiladjian, Jean-Jacques; Griesshammer, Martin; Masszi, Tamas; Durrant, Simon; Passamonti, Francesco; Harrison, Claire N; Pane, Fabrizio; Zachee, Pierre; Zhen, Huiling; Jones, Mark M; Parasuraman, Shreekant; Li, Jingjin; Côté, Isabelle; Habr, Dany; Vannucchi, Alessandro M

2016-08-01

Polycythemia vera (PV)-related symptoms may not be adequately controlled with conventional therapy. This current analysis of the RESPONSE trial evaluated the effects of ruxolitinib compared with standard therapy on quality of life (QoL) and symptoms in patients with PV who were hydroxyurea resistant/intolerant. In the previously reported primary analysis, ruxolitinib achieved the primary composite endpoint of hematocrit control and ≥35% reduction in spleen volume at Week 32. The current analysis evaluated patient-reported outcomes using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30), the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF), the Pruritus Symptom Impact Scale (PSIS), and the Patient Global Impression of Change (PGIC). Compared with standard therapy, ruxolitinib was associated with greater improvements in global health status/QoL, functional subscales, and individual symptom scores of the EORTC QLQ-C30. At Week 32, more patients in the ruxolitinib arm (44%) achieved a ≥10-point improvement in global health status/QoL vs. standard therapy (9%). Improvements in MPN-SAF symptom scores were consistent with improvements in EORTC QLQ-C30, PSIS, and PGIC scores. Ruxolitinib provides clinically relevant improvements in QoL and ameliorates symptom burden in patients with PV who are hydroxyurea resistant/intolerant. © 2016 The Authors. European Journal of Haematology Published by John Wiley & Sons Ltd.

The Saccharomyces cerevisiae MUM2 gene interacts with the DNA replication machinery and is required for meiotic levels of double strand breaks.

PubMed Central

Davis, L; Barbera, M; McDonnell, A; McIntyre, K; Sternglanz, R; Jin , Q; Loidl, J; Engebrecht, J

2001-01-01

The Saccharomyces cerevisiae MUM2 gene is essential for meiotic, but not mitotic, DNA replication and thus sporulation. Genetic interactions between MUM2 and a component of the origin recognition complex and polymerase alpha-primase suggest that MUM2 influences the function of the DNA replication machinery. Early meiotic gene expression is induced to a much greater extent in mum2 cells than in meiotic cells treated with the DNA synthesis inhibitor hydroxyurea. This result indicates that the mum2 meiotic arrest is downstream of the arrest induced by hydroxyurea and suggests that DNA synthesis is initiated in the mutant. Genetic analyses indicate that the recombination that occurs in mum2 mutants is dependent on the normal recombination machinery and on synaptonemal complex components and therefore is not a consequence of lesions created by incompletely replicated DNA. Both meiotic ectopic and allelic recombination are similarly reduced in the mum2 mutant, and the levels are consistent with the levels of meiosis-specific DSBs that are generated. Cytological analyses of mum2 mutants show that chromosome pairing and synapsis occur, although at reduced levels compared to wild type. Given the near-wild-type levels of meiotic gene expression, pairing, and synapsis, we suggest that the reduction in DNA replication is directly responsible for the reduced level of DSBs and meiotic recombination. PMID:11238403

Differential effects of hydroxyurea and INC424 on mutant allele burden and myeloproliferative phenotype in a JAK2-V617F polycythemia vera mouse model.

PubMed

Kubovcakova, Lucia; Lundberg, Pontus; Grisouard, Jean; Hao-Shen, Hui; Romanet, Vincent; Andraos, Rita; Murakami, Masato; Dirnhofer, Stephan; Wagner, Kay-Uwe; Radimerski, Thomas; Skoda, Radek C

2013-02-14

To establish a preclinical animal model for testing drugs with potential effects on myeloproliferative neoplasms (MPNs), we first performed a detailed phenotypic characterization of Cre-inducible transgenic JAK2-V617F mice. Deleting the conditional mouse Jak2-knockout alleles increased erythropoiesis and accentuated the polycythemia vera phenotype, but did not alter platelet or granulocyte levels. In a transplantation assay, JAK2-V617F(+) BM cells had an advantage over wild-type competitor cells. Using this competitive repopulation assay, we compared the effects of INC424 (ruxolitinib), a dual Jak1/Jak2 inhibitor, and hydroxyurea (HU). HU led to weight loss, but did not reduce spleen weight. The hematologic parameters were lowered and a slight decrease of the mutant allele burden was noted. INC424 had little effect on body weight, but strongly decreased spleen size and rapidly normalized RBC and neutrophil parameters. No significant decrease in the mutant allele burden was observed. INC424 reduced the phospho-Stat5 levels, whereas HU strongly increased phospho-Stat5, most likely because of the elevated erythropoietin levels in response to the HU-induced anemia. This compensatory increase in JAK/STAT signaling may counteract the beneficial effects of cytoreduction at higher doses of HU and represents an adverse effect that should be avoided.

Regulation of DNA repair in serum-stimulated xeroderma pigmentosum cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, P.K.; Sirover, M.A.

1984-10-01

The regulation of DNA repair during serum stimulation of quiescent cells was examined in normal human cells, in fibroblasts from three xeroderma pigmentosum complementation groups (A, C, and D), in xeroderma pigmentosum variant cells, and in ataxia telangiectasia cells. The regulation of nucleotide excision repair was examined by exposing cells to ultraviolet irradiation at discrete intervals after cell stimulation. Similarly, base excision repair was quantitated after exposure to methylmethane sulfonate. WI-38 normal human diploid fibroblasts, xeroderma pigmentosum variant cells, as well as ataxia telangiectasia cells enhanced their capacity for both nucleotide excision repair and for base excision repair prior tomore » their enhancement of DNA synthesis. Further, in each cell strain, the base excision repair enzyme uracil DNA glycosylase was increased prior to the induction of DNA polymerase using the identical cells to quantitate each activity. In contrast, each of the three xeroderma complementation groups that were examined failed to increase their capacity for nucleotide excision repair above basal levels at any interval examined. This result was observed using either unscheduled DNA synthesis in the presence of 10 mM hydroxyurea or using repair replication in the absence of hydroxyurea to quantitate DNA repair. However, each of the three complementation groups normally regulated the enhancement of base excision repair after methylmethane sulfonate exposure and each induced the uracil DNA glycosylase prior to DNA synthesis. 62 references, 3 figures, 2 tables.« less

Hydroxyurea inhibits parvovirus B19 replication in erythroid progenitor cells.

PubMed

Bonvicini, Francesca; Bua, Gloria; Conti, Ilaria; Manaresi, Elisabetta; Gallinella, Giorgio

2017-07-15

Parvovirus B19 (B19V) infection is restricted to erythroid progenitor cells (EPCs) of the human bone marrow, leading to transient arrest of erythropoiesis and severe complications mainly in subjects with underlying hematological disorders or with immune system deficits. Currently, there are no specific antiviral drugs for B19V treatment, but identification of compounds inhibiting B19V replication can be pursued by a drug repositioning strategy. In this frame, the present study investigates the activity of hydroxyurea (HU), the only disease-modifying therapy approved for sickle cell disease (SCD), towards B19V replication in the two relevant cellular systems, the UT7/EpoS1 cell line and EPCs. Results demonstrate that HU inhibits B19V replication with EC 50 values of 96.2µM and 147.1µM in UT7/EpoS1 and EPCs, respectively, providing experimental evidence of the antiviral activity of HU towards B19V replication, and confirming the efficacy of a drug discovery process by drug repositioning strategy. The antiviral activity occurs in vitro at concentrations lower than those affecting cellular DNA replication and viability, and at levels measured in plasma samples of SCD patients undergoing HU therapy. HU might determine a dual beneficial effect on SCD patients, not only for the treatment of the disease but also towards a virus responsible for severe complications. Copyright © 2017 Elsevier Inc. All rights reserved.

Hydroxyurea for nontransfusion-dependent β-thalassemia: A systematic review and meta-analysis.

PubMed

Algiraigri, Ali H; Wright, Nicola A M; Paolucci, Elizabeth Oddone; Kassam, Aliya

2017-09-01

Nontransfusion-dependent β-thalassemia (NTDβT) syndromes consist of β-thalassemia intermedia and moderate hemoglobin E/β thalassemias. They are characterized by varying degrees of chronic anemia and a wide spectrum of complications due to ineffective erythropoiesis and iron overload from chronic transfusions. Hydroxyurea (HU), an oral chemotherapeutic drug, is anticipated to decrease disease severity. We performed a meta-analysis to evaluate the clinical efficacy and safety of HU in NTDβT patients of any age. MEDLINE, EMBASE, Cochrane databases, and major conference proceedings for studies that assessed HU in NTDβT patients were searched. Qualities of eligible studies were assessed by National Institutes of Health tools. Seventeen studies, collectively involving 709 patients, fulfilled the eligibility criteria. HU was associated with a significant decrease in transfusion need in severe NTDβT with complete and overall (≥50%) response rates of 42% and 79%, respectively. For mild NTDβT, HU was effective in raising hemoglobin by 1g/L in 64% of patients. HU appears to be effective, well tolerated, and associated with mild and transient adverse events. NTDβT patients may benefit from a trial of HU, although large randomized clinical trials assessing its efficacy should be conducted to confirm the findings of this meta-analysis and to assess its long-term toxicity and response sustainability. Copyright © 2017 King Faisal Specialist Hospital & Research Centre. Published by Elsevier B.V. All rights reserved.

Anagrelide reduces thrombotic risk in essential thrombocythaemia vs. hydroxyurea plus aspirin.

PubMed

Dombi, Péter; Illés, Árpád; Demeter, Judit; Homor, Lajos; Simon, Zsofia; Karadi, Eva; Udvardy, Miklos; Egyed, Miklos

2017-02-01

To evaluate the reduction in thrombotic events (TE) in patients with essential thrombocythaemia (ET) treated with anagrelide versus hydroxyurea + aspirin (HU + ASA). A questionnaire was developed using 2008 WHO diagnostic criteria, and thrombotic risk factors were stratified according to Landolfi criteria. Through questionnaire completion, clinicians at Hungarian haematological centres entered data into the Hungarian MPN Registry on patients with myeloproliferative neoplasms. Based on ET registry data, TEs in anagrelide-treated patients (n = 139) were compared with HU + ASA-treated patients (n = 141). Patients were followed up for (median) 6 yr. TEs were reported in significantly fewer anagrelide-treated patients versus HU + ASA (15.1% versus 49.6%; P < 0.001). Numbers of major arterial and major venous events were similar between the groups, although there were over fivefold more minor arterial and minor venous events in the HU + ASA group (P < 0.001). While median age at diagnosis was older and length of follow-up shorter in the HU + ASA group (P < 0.05), this did not influence TE incidence; medication and TE before diagnosis only influenced TE incidence. Anagrelide significantly decreased the number of patients experiencing minor arterial and minor venous TEs versus HU + ASA over 6 yr. Risk of TE after diagnosis was significantly increased if the patient had TE before diagnosis. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Evaluation of the RBC Pig-a and PIGRET assays using single doses of hydroxyurea and melphalan in rats.

PubMed

Adachi, Hideki; Uematsu, Yasuaki; Yamada, Toru

2016-11-15

To evaluate the suitability of the rat Pig-a assay on reticulocytes (PIGRET assay) as a short-term test, red blood cell (RBC) Pig-a and PIGRET assays after single doses with hydroxyurea (HU) and melphalan (L-PAM) were conducted and the results of both assays were compared. HU was administered once orally to male SD rats at 250, 500 and 1000mg/kg, and both assays were conducted using peripheral blood withdrawn from the jugular vein at 1, 2 and 4 weeks after dosing. L-PAM was administered at 1.25, 2.5 and 5mg/kg in the same manner. L-PAM produced significant dose-dependent increases in mutant frequencies in the PIGRET assay after single oral doses, but did not produce dose-dependent increases in mutant frequencies in the RBC Pig-a assay. These results suggest that the PIGRET assay is more sensitive for the evaluation of the mutagenic potential of L-PAM than the RBC Pig-a assay. In contrast, HU, a clastogenic but not DNA-reactive compound, gave negative results in both assays. The results with these 2 chemicals indicate that the single-dose PIGRET assay in rats has the potential to properly detect DNA-reactive compounds that directly cause DNA damage in a short-term assay. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of hydroxyurea on blood rheology in sickle cell anemia: A two-years follow-up study.

PubMed

Lemonne, Nathalie; Möckesch, Berenike; Charlot, Keyne; Garnier, Yohann; Waltz, Xavier; Lamarre, Yann; Antoine-Jonville, Sophie; Etienne-Julan, Maryse; Hardy-Dessources, Marie-Dominique; Romana, Marc; Connes, Philippe

2017-01-01

The aim of the present study was to test the effects of hydroxyurea (HU) therapy on clinical, hematological and hemorheological parameters in adult patients with sickle cell anemia (SCA). Hematological and hemorheological parameters were measured in 28 SCA patients before HU therapy (i.e., baseline) and at 6, 12 and 24 months of treatment. RBC deformability was determined by ektacytometry at 30 Pa. RBC aggregation properties were investigated by light-backscatter method. Blood viscosity was measured at 225 s-1 by a cone-plate viscometer. The rates of vaso-occlusive crises and acute chest syndrome were lower at 1 and 2 years of HU therapy compared to baseline. The proportion of patients with leg ulcers tended to decrease after 2 years of treatment. Hemoglobin oxygen saturation improved with HU therapy. HU therapy induced a decrease of platelet and white blood cell counts and a rise in fetal hemoglobin level and mean cell volume. While hemoglobin concentrations increased under HU, blood viscosity remained unchanged all along the study. RBC deformability increased over baseline values at 6 months of HU therapy and continued to rise until the end of the follow-up period. In conclusion, the improvement in RBC deformability probably compensates the increase of hemoglobin on blood viscosity and participates to the improvement of the clinical status of patients.

Hydroxyurea enhances SMN2 gene expression through nitric oxide release.

PubMed

Xu, Cheng; Chen, Xin; Grzeschik, Susanna M; Ganta, Madhuri; Wang, Ching H

2011-02-01

Small molecules that increase full-length survivor motor neuron (SMN) gene transcript are promising therapeutic candidates for spinal muscular atrophy (SMA). Hydroxyurea (HU) has recently been shown to increase full-length SMN transcript in cultured lymphocytes from patients with SMA. We investigate the mechanism by which HU enhances full-length SMN2 gene expression in SMA lymphocytes. Nitric oxide (NO) is a major intracellular metabolite of HU. We test whether NO donors can themselves enhance full-length SMN2 expression. Eighteen cell lines (five type I, five type II, six type III SMA, and two non-SMA controls) were treated with or without NO donors for 48 h. SMA cells treated with HU and three NO donors: two long-acting donors, Deta-NONOate and S-nitrosoglutathione, and one short-acting donor, 3-ethyl-3-(ethylaminoethyl)-1-hydroxy-2-oxo-1-triazene, resulted in significant increase in full-length SMN2 mRNA. These effects were abolished by co-treatment with an NO scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide. One short-acting NO donor, S-nitroso-N-acetyl-DL-penicillamine, failed to show significant effect on full-length SMN2 expression, possibly due to high degree of cytotoxicity. These results were observed using both densitometry and quantitative PCR methods. We conclude that HU enhances SMN2 expression through the release of NO. NO donors may themselves be considered as new therapeutic candidates for SMA.

TiO(2) doping by hydroxyurea at the nucleation stage: towards a new photocatalyst in the visible spectral range.

PubMed

Azouani, R; Tieng, S; Chhor, K; Bocquet, J-F; Eloy, P; Gaigneaux, E M; Klementiev, K; Kanaev, A V

2010-10-07

We report an original method of preparation of OCN-doped TiO(2) for photocatalysis in the visible spectral range. The preparation is achieved by a sol-gel route using titanium tetraisopropoxide precursor. Special attention was paid to fluid micromixing, which enables homogeneous reaction conditions in the reactor bulk and monodispersity of the produced clusters/nanoparticles. The dopant hydroxyurea (HyU, CH(4)N(2)O(2)) is injected into the reactive fluid at the nucleation stage, which lasts tens of milliseconds. The doping results in a strong yellow coloration of the nanocolloids due to the absorption band in the spectral range 380-550 nm and accelerates the aggregation kinetics of both nuclei at the induction stage and sub-nuclei units (clusters) at the nucleation stage. FTIR, Raman and UV-visible absorption analyses show the formation of a stable HyU-TiO(2) complex. EXAFS spectra indicate no appreciable changes of the first-shell Ti atom environment. The doping agent takes available surface sites of TiO(2) clusters/nanoparticles attaining ∼10% molar loading. The reaction kinetics then accelerates due to a longer collisional lifetime between nanoparticles induced by the formation of a weak [double bond, length as m-dash]OTi bond. The OCN-group bonding to titanium atoms produces a weakening of the C[double bond, length as m-dash]O double bond and a strengthening of the C-N and N-O bonds.

Clinical Course of Two Children with Unstable Hemoglobins: The Effect of Hydroxyurea Therapy.

PubMed

Loovers, Harriët M; Tamminga, Nienke; Mulder, André B; Tamminga, Rienk Y J

2016-09-01

Case reports on the effect of hydroxyurea (HU) therapy for unstable hemoglobins (Hbs) are sparse; only three adult cases have been reported. We report for the first time on the effect of HU therapy in children carrying unstable Hbs. The first case concerns a female child with a familial history of chronic hemolytic anemia. She was diagnosed with Hb Volga (HBB: c.83C>A) at the age of 7 months. At age 6, treatment options were reconsidered due to increasing fatigue and decreasing Hb concentration. The second case also concerns a female child with chronic hemolytic anemia and icterus since the age of 5. She was diagnosed with Hb Köln (HBB: c.295G>A) at the age of 9. At age 10, treatment options were reconsidered due to decreased general condition and poor school performance. Both children were started on HU therapy. The child with Hb Volga showed reduced clinical symptoms and increased average Hb concentrations. She has been on HU therapy for over 7 years at preparation of this manuscript. The child with Hb Köln showed decreasing Hb concentrations upon start of therapy; clinical symptoms did not improve. Therapy was discontinued after 3½ months. The Hb Volga case report suggests that HU therapy could improve clinical symptoms in some patients with unstable Hbs. Based on these and previously published cases, it was speculated that response can be predicted by the percentage of Hb F and reticulocyte counts.

Comparison of MicroRNAs Mediated in Reactivation of the γ-Globin in β-Thalassemia Patients, Responders and Non-Responders to Hydroxyurea.

PubMed

Hojjati, Mohammad T; Azarkeivan, Azita; Pourfathollah, Ali A; Amirizadeh, Naser

2017-03-01

Drug induction of Hb F seems to be an ideal therapy for patients with hemoglobin (Hb) disorders, and many efforts have been made to reveal the mechanism behind it. Thus, we examined in vivo expression of some microRNAs (miRNAs) that are thought to be involved in this process. Among β-thalassemia (β-thal) patients who were undergoing hydroxyurea (HU) therapy in the past 3 months and five healthy individuals, five responders and five non-responders, were also included in the study. Erythroid progenitors were isolated by magnetic activated cell sorting (MACS) and miRNA expression analyzed using reverse transcription-polymerase chain reaction (RT-PCR). We showed that γ-globin, miR-210 and miR-486-3p had higher levels in the responders than the non-responders group. Moreover, miR-150 and miR-320 had higher levels in the healthy group than both non-responders and responders groups, but the expression of miR-96 did not show any significant difference between the study groups. To the best of our knowledge, this is the first study proposing that 'induction of cellular hypoxic condition by Hb F inducing agents' could be the milestone of possible mechanisms that explain why responders are able to reactivate γ-globin genes and subsequently, more production of Hb F, in response to these agents in comparison to non-responders. However, further investigations need to be performed to verify this hypothesis.

Caffeine-Induced Premature Chromosome Condensation Results in the Apoptosis-Like Programmed Cell Death in Root Meristems of Vicia faba

PubMed Central

Rybaczek, Dorota; Musiałek, Marcelina Weronika; Balcerczyk, Aneta

2015-01-01

We have demonstrated that the activation of apoptosis-like programmed cell death (AL-PCD) was a secondary result of caffeine (CF) induced premature chromosome condensation (PCC) in hydroxyurea-synchronized Vicia faba root meristem cells. Initiation of the apoptotic-like cell degradation pathway seemed to be the result of DNA damage generated by treatment with hydroxyurea (HU) [double-stranded breaks (DSBs) mostly] and co-treatment with HU/CF [single-stranded breaks (SSBs) mainly]. A single chromosome comet assay was successfully used to study different types of DNA damage (neutral variant–DSBs versus alkaline–DSBs or SSBs). The immunocytochemical detection of H2AXS139Ph and PARP-2 were used as markers for DSBs and SSBs, respectively. Acridine orange and ethidium bromide (AO/EB) were applied for quantitative immunofluorescence measurements of dead, dying and living cells. Apoptotic-type DNA fragmentation and positive TUNEL reaction finally proved that CF triggers AL-PCD in stressed V. faba root meristem cells. In addition, the results obtained under transmission electron microscopy (TEM) further revealed apoptotic-like features at the ultrastructural level of PCC-type cells: (i) extensive vacuolization; (ii) abnormal chromatin condensation, its marginalization and concomitant degradation; (iii) formation of autophagy-like vesicles (iv) protoplast shrinkage (v) fragmentation of cell nuclei and (vi) extensive degeneration of the cells. The results obtained have been discussed with respect to the vacuolar/autolytic type of plant-specific AL-PCD. PMID:26545248

The dynamics of histone H2A ubiquitination in HeLa cells exposed to rapamycin, ethanol, hydroxyurea, ER stress, heat shock and DNA damage.

PubMed

Nakata, Shiori; Watanabe, Tadashi; Nakagawa, Koji; Takeda, Hiroshi; Ito, Akihiro; Fujimuro, Masahiro

2016-03-25

Polyubiquitination plays key roles in proteasome-dependent and independent cellular events, whereas monoubiquitination is involved in gene expression, DNA repair, protein-protein interaction, and protein trafficking. We previously developed an FK2 antibody, which specifically recognizes poly-Ub moieties but not free Ub. To elucidate the role of Ub conjugation in response to cellular stress, we used FK2 to investigate whether chemical stress (rapamycin, ethanol, or hydroxyurea), ER stress (thapsigargin or tunicamycin), heat shock or DNA damage (H2O2 or methyl methanesulfonate) affect the formation of Ub conjugates including histone H2A (hH2A) ubiquitination. First, we found that all forms of stress tested increased poly-ubiquitinated proteins in HeLa cells. Furthermore, rapamycin and hydroxyurea treatment, and ER stress increased ubiquitination of hH2A, while methyl methanesulfonate (MMS) treatment induced deubiquitination of hH2A. The ethanol and H2O2 treatments, and heat shock transiently induced hH2A de-ubiquitination, although deubiquitinated hH2A were ubiquitinated again by subsequent cultivation. We also revealed that FK2 reacts with not only polyubiquitinated proteins but also mono-ubiquitinated hH2A. With the exception of MMS, all forms of stress tested increased the acetylation of K5-hH2A, K9-hH3 and K8-hH4 in addition to ubiquitination. K118 and K119 of hH2A were ubiquitinated in cells under normal conditions, and K119 was the major ubiquitination site. The MMS-treatment and heat shock induced the deubiquitination of both K118 and K119-histone H2A. Interestingly, MMS treatment did not affect cell HeLa cell viability expressing double-mutant hH2A (KK118,119AA-hH2A), while heat shock slightly but significantly decreased viability of double-mutant hH2A expressing cells, indicating that ubiquitination of both sites associates with recovery from heat shock but not MMS treatment. Thus, we characterized FK2 reactivity and demonstrated that various stresses alter the ubiquitination status, particularly ubiquitinated hH2A and with histone acetylation, and highlight the physiological importance of hH2A ubiquitination after exposure to stress stimuli. Copyright © 2016 Elsevier Inc. All rights reserved.

Methods for Teratogenic Screening of Air Force Chemicals

DTIC Science & Technology

1978-01-01

7 2 4 3 2.3 7 8 2 1 7 2.6 8 5 1 1 4 2.5 20 0 10 22 8 1 1 7 2.8 26 6 5 2 4 2.4 3 Gross Abnormalities Number of Fetuses with Abnormality Anophthalmia ...meningoencephalocoele), anophthalmia , cleft palate, cleft lip, misplaced ears, clubbed hind limbs, fused vertebrae, fused ribs, split centra and scoliosis.* In...experimentation with hydroxyurea in Fisher 344 rats, at 250 mg/kg on day nine of pregnancy, our results showed anophthalmia , brain abnormalities

Multiple myeloma on polycythemia vera following radioactive phosphorus therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

West, W.O.

1976-11-01

A 74-year-old white man with established polycythemia vera was treated with radioactive phosphorus after phlebotomies alone failed to control his disease. About 2/sup 3///sub 4/ years later he died of multiple myeloma. The mutagenic effect of radioactive phosphorus may have caused or possibly accelerated preexisting myeloma. Basic nonmalignant disease deserves careful consideration before radiation or radiomimetic agents are used. One might consider a probably less mutagenic drug such as hydroxyurea in patients with polycythemia vera when phlebotomy alone does not give good control of red cell mass and thrombocytosis.

Alteration of adenyl dinucleotide metabolism by environmental stress.

PubMed Central

Baker, J C; Jacobson, M K

1986-01-01

Exposure of cultured mammalian cells to a variety of conditions that induce the synthesis of stress proteins, including hyperthermia, ethanol, cadmium, and arsenite resulted in an increased cellular content of adenyl dinucleotides including diadenosine tetraphosphate (Ap4A). Exposure to other agents that cause metabolic perturbations not known to induce the synthesis of stress proteins, such as cyclohexamide, cytosine arabinoside, hydroxyurea, and ultraviolet irradiation did not alter the content of these nucleotides. It is proposed that these unique nucleotides may mediate adaptive responses of mammalian cells to environmental stress. PMID:3458199

Potential of Three Ethnomedicinal Plants as Antisickling Agents.

PubMed

Nurain, Ismaila O; Bewaji, Clement O; Johnson, Jarrett S; Davenport, Robertson D; Zhang, Yang

2017-01-03

Sickle cell disease (SCD) is a genetic blood disorder that affects the shape and transportation of red blood cells (RBCs) in blood vessels, leading to various clinical complications. Many drugs that are available for treating the disease are insufficiently effective, toxic, or too expensive. Therefore, there is a pressing need for safe, effective, and inexpensive therapeutic agents from indigenous plants used in ethnomedicines. The potential of aqueous extracts of Cajanus cajan leaf and seed, Zanthoxylum zanthoxyloides leaf, and Carica papaya leaf in sickle cell disease management was investigated in vitro using freshly prepared 2% sodium metabisulfite for sickling induction. The results indicated that the percentage of sickled cells, which was initially 91.6% in the control, was reduced to 29.3%, 41.7%, 32.8%, 38.2%, 47.6%, in the presence of hydroxyurea, C. cajan seed, C. cajan leaf, Z. zanthoxyloides leaf, and C. papaya leaf extracts, respectively, where the rate of polymerization inhibition was 6.5, 5.9, 8.0, 6.6, and 6.0 (×10 -2 ) accordingly. It was also found that the RBC resistance to hemolysis was increased in the presence of the tested agents as indicated by the reduction of the percentage of hemolyzed cells from 100% to 0%. The phytochemical screening results indicated the presence of important phytochemicals including tannins, saponins, alkaloids, flavonoids, and glycosides in all the plant extracts. Finally, gas chromatography-mass spectrometry analysis showed the presence of important secondary metabolites in the plants. These results suggest that the plant extracts have some potential to be used as alternative antisickling therapy to hydroxyurea in SCD management.

Hydroxycarbamide treatment and brain MRI/MRA findings in children with sickle cell anaemia.

PubMed

Nottage, Kerri A; Ware, Russell E; Aygun, Banu; Smeltzer, Matthew; Kang, Guolian; Moen, Joseph; Wang, Winfred C; Hankins, Jane S; Helton, Kathleen J

2016-10-01

Silent cerebral infarction (SCI) is the most common neurological abnormality among children with sickle cell anaemia (SCA). The effect of hydroxycarbamide (also termed hydroxyurea) on the development and progression of SCI is unclear. We evaluated brain magnetic resonance imaging/angiography (MRI/MRA) in children with SCA receiving long-term hydroxycarbamide therapy. Fifty participants (median 9·4 years, range 1·1-17·3) enrolled in the Hydroxyurea Study of Long-Term Effects (HUSTLE; NCT00305175) underwent brain MRI/MRA and laboratory evaluations before hydroxycarbamide initiation and after 3 and 6 years of treatment to maximum tolerated dose. SCI and vascular stenosis were evaluated. At baseline, 3 and 6 years, SCI were present in 19/50 (38%), 20/49 (41%), and 7/17 (41%), respectively. At 3 years, one child developed a SCI lesion, and another progressed (single lesion to multiple). Lower haemoglobin (Hb) (80 g/l vs. 86 g/l, P = 0·049), fetal Hb (5·0% vs. 10·4%, P < 0·001) and oxygen saturation (97% vs. 98%, P = 0·027) before hydroxycarbamide initiation were associated with SCI. No patients had vascular stenosis identified on MRA, transient ischaemic attack or stroke. Our data indicate that children receiving hydroxycarbamide over a 3- to 6-year period have a low rate of new or worsening cerebrovascular disease. Further studies are needed to confirm that hydroxycarbamide can prevent the onset and progression of SCI. © 2016 John Wiley & Sons Ltd.

Magnetic resonance imaging/angiography and transcranial Doppler velocities in sickle cell anemia: results from the SWiTCH trial

PubMed Central

Helton, Kathleen J.; Adams, Robert J.; Kesler, Karen L.; Lockhart, Alex; Aygun, Banu; Driscoll, Catherine; Heeney, Matthew M.; Jackson, Sherron M.; Krishnamurti, Lakshmanan; Miller, Scott T.; Sarnaik, Sharada A.; Schultz, William H.

2014-01-01

The Stroke With Transfusions Changing to Hydroxyurea (SWiTCH) trial compared standard (transfusions/chelation) to alternative (hydroxyurea/phlebotomy) treatment to prevent recurrent stroke and manage iron overload in children chronically transfused over 7 years before enrollment. Standardized brain magnetic resonance imaging/magnetic resonance angiography (MRA) and transcranial Doppler (TCD) exams were performed at entry and exit, with a central blinded review. A novel MRA vasculopathy grading scale demonstrated frequent severe baseline left/right vessel stenosis (53%/41% ≥Grade 4); 31% had no vessel stenosis on either side. Baseline parenchymal injury was prevalent (85%/79% subcortical, 53%/37% cortical, 50%/35% subcortical and cortical). Most children had low or uninterpretable baseline middle cerebral artery TCD velocities, which were associated with worse stenoses (incidence risk ratio [IRR] = 5.1, P ≤ .0001 and IRR = 4.1, P < .0001) than normal velocities; only 2% to 12% had any conditional/abnormal velocity. Patients with adjudicated stroke (7) and transient ischemic attacks (19 in 11 standard/8 alternative arm subjects) had substantial parenchymal injury/vessel stenosis. At exit, 1 child (alternative arm) had a new silent infarct, and another had worse stenosis. SWiTCH neuroimaging data document severe parenchymal and vascular abnormalities in children with SCA and stroke and support concerns about chronic transfusions lacking effectiveness for preventing progressive cerebrovascular injury. The novel SWiTCH vasculopathy grading scale warrants validation testing and consideration for use in future clinical trials. This trial was registered at www.clinicaltrials.gov as #NCT00122980. PMID:24914136

The leukemia-associated Rho guanine nucleotide exchange factor LARG is required for efficient replication stress signaling

PubMed Central

Beveridge, Ryan D; Staples, Christopher J; Patil, Abhijit A; Myers, Katie N; Maslen, Sarah; Skehel, J Mark; Boulton, Simon J; Collis, Spencer J

2014-01-01

We previously identified and characterized TELO2 as a human protein that facilitates efficient DNA damage response (DDR) signaling. A subsequent yeast 2-hybrid screen identified LARG; Leukemia-Associated Rho Guanine Nucleotide Exchange Factor (also known as Arhgef12), as a potential novel TELO2 interactor. LARG was previously shown to interact with Pericentrin (PCNT), which, like TELO2, is required for efficient replication stress signaling. Here we confirm interactions between LARG, TELO2 and PCNT and show that a sub-set of LARG co-localizes with PCNT at the centrosome. LARG-deficient cells exhibit replication stress signaling defects as evidenced by; supernumerary centrosomes, reduced replication stress-induced γH2AX and RPA nuclear foci formation, and reduced activation of the replication stress signaling effector kinase Chk1 in response to hydroxyurea. As such, LARG-deficient cells are sensitive to replication stress-inducing agents such as hydroxyurea and mitomycin C. Conversely we also show that depletion of TELO2 and the replication stress signaling kinase ATR leads to RhoA signaling defects. These data therefore reveal a level of crosstalk between the RhoA and DDR signaling pathways. Given that mutations in both ATR and PCNT can give rise to the related primordial dwarfism disorders of Seckel Syndrome and Microcephalic osteodysplastic primordial dwarfism type II (MOPDII) respectively, which both exhibit defects in ATR-dependent checkpoint signaling, these data also raise the possibility that mutations in LARG or disruption to RhoA signaling may be contributory factors to the etiology of a sub-set of primordial dwarfism disorders. PMID:25485589

Hydroxyurea and Growth in Young Children With Sickle Cell Disease

PubMed Central

Houston, Patricia E.; Wang, Winfred C.; Iyer, Rathi V.; Goldsmith, Jonathan; Casella, James F.; Reed, Caroline K.; Rogers, Zora R.; Waclawiw, Myron A.; Thompson, Bruce

2014-01-01

BACKGROUND: Growth impairment is a known complication of sickle cell disease. Effects of hydroxyurea (HU) on growth in very young children are not known. METHODS: Height, weight, BMI, and head circumference (HC) were compared with World Health Organization (WHO) standards in BABY HUG, a multicenter, randomized, double-blinded, placebo-controlled 2-year clinical trial of HU in 193 children 9 to 18 months of age. Anthropometric data were closely monitored and converted to z scores by using WHO standardized algorithms for descriptive analyses. The treatment and placebo groups were compared longitudinally by using a mixed model analysis. RESULTS: At entry, the z scores of BABY HUG children were higher than WHO norms. After 2 years of HU or placebo treatment, there were no significant differences between the groups, except for the mean HC z scores at study exit (HU: +0.8 versus placebo: +1.0, P = .05). Baseline z scores were the best predictors of z scores at study exit. The absolute neutrophil count, absolute reticulocyte count, and total white blood cell count had significant negative correlations with growth measures. CONCLUSIONS: Both groups had normal or near normal anthropometric measures during the study. The HC z scores at study entry and exit were slightly greater than WHO norms. Higher baseline white blood cell count, absolute reticulocyte count, and absolute neutrophil count were associated with poorer growth. The significance of the slightly lower HC in the treatment group at study exit is not clear. Trends toward normalization of weight and height and effects on HC will be monitored in ongoing BABY HUG follow-up studies. PMID:25157002

[Symptomatic extramedullary haematopoiesis in β-thalassemia: A retrospective single centre study].

PubMed

Maazoun, F; Gellen Dautremer, J; Boutekadjirt, A; Pissard, S; Habibi, A; Bachir, D; Rahmouni, A; Bartolucci, P; Debbache, K; Lagrange, J-L; Michel, M; Galacteros, F

2016-01-01

Symptomatic extramedullary hematopoiesis (EH) is a rare but potentially severe phenomenon which occurs in β-thalassemia. There are no treatment guidelines. Retrospective single centre study including the cases of symptomatic EH encountered between 1997 and 2014 in a unit specialised in red blood cell genetic disorders. Description of clinical, biological and radiological characteristics of the patients, treatments received, and outcomes. Among 182 β-thalassemia patients followed during the study period, 7 cases of symptomatic EH were diagnosed. They were 5 men and 2 women, and their mean age was 37 years. Four patients were splenectomised, two patients were regularly transfused, and four patients had already received erythropoietin. EH was localised in intravertebral areas and responsible for dorsal spinal cord compression in 5 patients, in paravertebral dorsal area in 1 patient, and in presacral area in 1 patient. The mean hemoglobin level at diagnosis was 7.9 g/dL. Treatment administered included: red cell transfusion in 6 cases, associated with hydroxyurea in 5 cases and/or radiotherapy in 3 patients. One patient was treated with surgery and HU. After a median follow-up of 41 months, clinical recovery was complete in 2 patients and partial in 5 patients. EH must be suspected in β-thalassemia in patients presenting clinical signs of organ compression, and a typical radiological aspect. The functional prognosis depends on the rapidity of treatment, which includes red blood cell transfusion, hydroxyurea, radiotherapy, and rarely surgery. Long-term outcome is uncertain. Copyright © 2015. Published by Elsevier SAS.

New Late Gene, dar, Involved in DNA Replication of Bacteriophage T4 I. Isolation, Characterization, and Genetic Location.

PubMed

Wu, J R; Yeh, Y C

1975-05-01

Suppressors of gene 59-defective mutants were isolated by screening spontaneous, temperature-sensitive (ts) revertants of the amber mutant, amC5, in gene 59. Six ts revertants were isolated. No gene 59-defective ts recombinant was obtained by crossing each ts revertant with the wild type, T4D. However, suppressors of gene 59-defective mutants were obtained from two of these ts revertants. These suppressor mutants are referred to as dar (DNA arrested restoration). dar mutants specifically restored the abnormalities, both in DNA synthesis and burst size, caused by gene 59-defective mutants to normal levels. It is unlikely that dar mutants are nonsense suppressors since theý failed to suppress amber mutations in 11 other genes investigated. The genetic expression of dar is controlled by gene 55; therefore, dar is a late gene. The genetic location of dar has been mapped between genes 24 and 25, a region contiguous to late genes. dar appears to be another nonessential gene of T4 since burst sizes of dar were almost identical to those of the wild type. Mutations in dar did not affect genetic recombination and repair of UV-damaged DNA, but caused a sensitivity to hydroxyurea in progeny formation. The effect of the dar mutation on host DNA degradation cannot account for its hydroxyurea sensitivity. dar mutant alleles were recessive to the wild-type allele as judged by restoration of arrested DNA synthesis. The possible mechanisms for the suppression of defects in gene 59 are discussed.

Cell cycle progression in irradiated endothelial cells cultured from bovine aorta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rubin, D.B.; Drab, E.A.; Ward, W.F.

1988-11-01

Logarithmically growing endothelial cells from bovine aortas were exposed to single doses of 0-10 Gy of 60Co gamma rays, and cell cycle phase distribution and progression were examined by flow cytometry and autoradiography. In some experiments, cells were synchronized in the cell cycle with hydroxyurea (1 mM). Cell number in sham-irradiated control cultures doubled in approximately 24 h. Estimated cycle stage times for control cells were 14.4 h for G1 phase, 7.2 h for S phase, and 2.4 h for G2 + M phase. Irradiated cells demonstrated a reduced distribution at the G1/S phase border at 4 h, and anmore » increased distribution in G2 + M phase at 24 h postirradiation. Autoradiographs of irradiated cells after continuous (3H)thymidine labeling indicated a block in G1 phase or at the G1/S-phase border. The duration of the block was dose dependent (2-3 min/cGy). Progression of the endothelial cells through S phase after removal of the hydroxyurea block also was retarded by irradiation, as demonstrated by increased distribution in early S phase and decreased distribution in late S phase. These results indicate that progression of asynchronous cultured bovine aortic endothelial cells through the DNA synthetic cycle is susceptible to radiation inhibition at specific sites in the cycle, resulting in redistribution and partial synchronization of the population. Thus aortic endothelial cells, diploid cells from a normal tissue, resemble many immortal cell types that have been examined in this regard in vitro.« less

Pharmacokinetics and bioequivalence of a liquid formulation of hydroxyurea in children with sickle cell anemia.

PubMed

Estepp, Jeremie H; Melloni, Chiara; Thornburg, Courtney D; Wiczling, Paweł; Rogers, Zora; Rothman, Jennifer A; Green, Nancy S; Liem, Robert; Brandow, Amanda M; Crary, Shelley E; Howard, Thomas H; Morris, Maurine H; Lewandowski, Andrew; Garg, Uttam; Jusko, William J; Neville, Kathleen A

2016-03-01

Hydroxyurea (HU) is a crucial therapy for children with sickle cell anemia, but its off-label use is a barrier to widespread acceptance. We found HU exposure is not significantly altered by liquid vs capsule formulation, and weight-based dosing schemes provide consistent exposure. HU is recommended for all children starting as young as 9 months of age with sickle cell anemia (SCA; HbSS and HbSβspan(0) thalassemia); however; a paucity of pediatric data exists regarding the pharmacokinetics (PK) or the exposure-response relationship of HU. This trial aimed to characterize the PK of HU in children and to evaluate and compare the bioavailability of a liquid vs capsule formulation. This multicenter; prospective; open-label trial enrolled 39 children with SCA who provided 682 plasma samples for PK analysis following administration of HU. Noncompartmental and population PK models are described. We report that liquid and capsule formulations of HU are bioequivalent; weight-based dosing schemes provide consistent drug exposure; and age-based dosing schemes are unnecessary. These data support the use of liquid HU in children unable to swallow capsules and in those whose weight precludes the use of fixed capsule formulations. Taken with existing safety and efficacy literature; these findings should encourage the use of HU across the spectrum of age and weight in children with SCA; and they should facilitate the expanded use of HU as recommended in the National Heart; Lung; and Blood Institute guidelines for individuals with SCA. © 2015, The American College of Clinical Pharmacology.

Developmental Injury to the Cerebellar Cortex Following Hydroxyurea Treatment in Early Postnatal Life: An Immunohistochemical and Electron Microscopic Study.

PubMed

Martí, Joaquín; Molina, Vanesa; Santa-Cruz, M C; Hervás, José P

2017-02-01

Postnatal development of the cerebellar cortex was studied in rats administered with a single dose (2 mg/g) of the cytotoxic agent hydroxyurea (HU) on postnatal day (P) 9 and collected at appropriate times ranging from 6 h to 45 days. Quantification of several parameters such as the density of pyknotic, mitotic, BrdU-positive, and vimentin-stained cells revealed that HU compromises the survival of the external granular layer (EGL) cells. Moreover, vimentin immunocytochemistry revealed overexpression and thicker immunoreactive glial processes in HU-treated rats. On the other hand, we also show that HU leads to the activation of apoptotic cellular events, resulting in a substantial number of dying EGL cells, as revealed by TUNEL staining and at the electron microscope level. Additionally, we quantified several features of the cerebellar cortex of rats exposed to HU in early postnatal life and collected in adulthood. Data analysis indicated that the analyzed parameters were less pronounced in rats administered with this agent. Moreover, we observed several alterations in the cerebellar cortex cytoarchitecture of rats injected with HU. Anomalies included ectopic placement of Purkinje cells and abnormities in the dendritic arbor of these macroneurons. Ectopic granule cells were also found in the molecular layer. These findings provide a clue for investigating the mechanisms of HU-induced toxicity during the development of the central nervous system. Our results also suggest that it is essential to avoid underestimating the adverse effects of this hydroxylated analog of urea when administered during early postnatal life.

Effect of Spirulina maxima and its protein extract on micronuclei induction by hydroxyurea in pregnant mice and their fetuses.

PubMed

Álvarez-González, Isela; Vázquez-Sánchez, Jorge; Chamorro-Cevallos, Germán; Madrigal-Bujaidar, Eduardo

2013-11-01

The purpose of the present report was to determine the inhibitory effect of Spirulina maxima (Sm) and its protein extract (PE), mainly consisting of C-phycocyanin, on the increase in micronuclei and bone marrow cytotoxicity induced by hydroxyurea (HU) in pregnant mice and their fetuses. The two tested antimutagenic agents were administered daily from day 10 to day 18 of pregnancy, and HU (300 mg/kg) was administered once on day 16 of the assay. The experimental design also included mice that were administered only Sm or PE (1000 and 400 mg/kg, respectively), two control groups that were administered with vehicles (water and 0.5% Tween 80), and one additional group that was treated solely with HU. Blood samples from the pregnant mice and their fetuses were examined at day 19 of pregnancy. Significant increases in the number of micronucleated polychromatic erythrocytes and in the total number of micronucleated erythrocytes were observed in all HU-treated animals. In contrast, similarly low numbers of micronuclei were observed in the two control groups and in the groups treated with Sm and PE alone. The administration of Sm (100, 500, and 1000 mg/kg) and PE (100, 200, and 400 mg/kg) to HU-treated animals conferred moderate genotoxic protection (∼30%) and some protection against the cytotoxicity induced by HU in mice. The obtained results provide new information regarding the capacity of the tested agents to confer protection to adult mice and transplacentally, as well as on a specific subclass of micronuclei.

Mechanisms of neurotoxicity induced in the developing brain of mice and rats by DNA-damaging chemicals.

PubMed

Doi, Kunio

2011-01-01

It is not widely known how the developing brain responds to extrinsic damage, although the developing brain is considered to be sensitive to diverse environmental factors including DNA-damaging agents. This paper reviews the mechanisms of neurotoxicity induced in the developing brain of mice and rats by six chemicals (ethylnitrosourea, hydroxyurea, 5-azacytidine, cytosine arabinoside, 6-mercaptopurine and etoposide), which cause DNA damage in different ways, especially from the viewpoints of apoptosis and cell cycle arrest in neural progenitor cells. In addition, this paper also reviews the repair process following damage in the developing brain.

Evaluation of γ-Induced Apoptosis in Human Peripheral Blood Lymphocytes

NASA Astrophysics Data System (ADS)

Baranova, Elena; Boreyko, Alla; Ravnachka, Ivanka; Saveleva, Maria

2010-01-01

Several experiments have been performed to study regularities in the induction of apoptotic cells in human lymphocytes by 60Co γ-rays at different times after irradiation. Apoptosis induction by 60Co γ-rays in human lymphocytes in different cell cycle phases (G0, S, G1, and G2) has been studied. The maximal apoptosis output in lymphocyte cells was observed in the S phase. Modifying effect of replicative and reparative DNA synthesis inhibitors—1- β -D-arabinofuranosylcytosine (Ara-C) and hydroxyurea (Hu)—on the kinetics of 60Co γ-rays induced apoptosis in human lymphocytes has been studied.

Cholelithiasis and its complications in sickle cell disease in a university hospital.

PubMed

Martins, Raquel Alves; Soares, Renato Santos; Vito, Fernanda Bernadelli De; Barbosa, Valdirene de Fátima; Silva, Sheila Soares; Moraes-Souza, Helio; Martins, Paulo Roberto Juliano

The clinical manifestations of sickle cell disease are related to the polymerization of hemoglobin S. The chronic hemolysis caused by this condition often causes the formation of gallstones that can migrate and block the common bile duct leading to acute abdomen. This study aimed to evaluate the profile of patients with sickle cell disease and cholelithiasis. Patients with sickle cell disease were separated into groups according to the presence or absence of cholelithiasis. Socioepidemiological and clinical characteristics, such as gender, age, use of hydroxyurea and the presence of other hemoglobinopathies were researched in the medical records of patients. A hundred and seven patients with sickle cell anemia were treated at the institution. Of these, 27 (25.2%) had cholelithiasis. The presence of cholelithiasis was higher in the 11-29 age group than in younger than 11 years and over 29 years. No association was found for the presence of cholelithiasis with gender, use of hydroxyurea or type of hemoglobinopathy (hemoglobin SS, hemoglobin SC or sickle beta-thalassemia). Sixteen of the patients had to be submitted to cholecystectomy with 14 of the surgeries being performed by laparoscopy. Complications were observed in three patients and one patient died for reasons unrelated to the surgery. A quarter of patients with sickle cell disease had gallstones, more commonly in the 11- to 29-year age range. Patients should be monitored from childhood to prevent cholelithiasis with preoperative, intra-operative and postoperative care being crucial to reduce the risk of complications in these patients. Copyright © 2016 Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular. Published by Elsevier Editora Ltda. All rights reserved.

Organ iron accumulation in chronically transfused children with sickle cell anaemia: baseline results from the TWiTCH trial.

PubMed

Wood, John C; Cohen, Alan R; Pressel, Sara L; Aygun, Banu; Imran, Hamayun; Luchtman-Jones, Lori; Thompson, Alexis A; Fuh, Beng; Schultz, William H; Davis, Barry R; Ware, Russell E

2016-01-01

Transcranial Doppler (TCD) With Transfusions Changing to Hydroxyurea (TWiTCH) trial is a randomized, open-label comparison of hydroxycarbamide (also termed hydroxyurea) versus continued chronic transfusion therapy for primary stroke prevention in patients with sickle cell anaemia (SCA) and abnormal TCD. Severity and location of iron overload is an important secondary outcome measure. We report the baseline findings of abdominal organ iron burden in 121 participants. At enrollment, patients were young (9·8 ± 2·9 years), predominantly female (60:40), and previously treated with transfusions (4·1 ± 2·4 years) and iron chelation (3·1 ± 2·1 years). Liver iron concentration (LIC; 9·0 ± 6·6 mg/g dry weight) and serum ferritin were moderately elevated (2696 ± 1678 μg/l), but transferrin was incompletely saturated (47·2 ± 23·6%). Spleen R2* was 509 ± 399 Hz (splenic iron ~13·9 mg/g) and correlated with LIC (r(2)  = 0·14, P = 0·0008). Pancreas R2* was increased in 38·3% of patients but not to levels associated with endocrine toxicity. Kidney R2* was increased in 80·7% of patients; renal iron correlated with markers of intravascular haemolysis and was elevated in patients with increased urine albumin-creatinine ratios. Extra-hepatic iron deposition is common among children with SCA who receive chronic transfusions, and could potentiate oxidative stress caused by reperfusion injury and decellularized haemoglobin. © 2015 John Wiley & Sons Ltd.

From leeches to personalized medicine: evolving concepts in the management of polycythemia vera.

PubMed

Vannucchi, Alessandro M

2017-01-01

Polycythemia vera is a clonal disorder of hematopoietic stem/progenitor cells. It manifests as an expansion of red cell mass. It is the most common chronic myeloproliferative neoplasm. In virtually all cases, it is characterized by a V617F point mutation in JAK2 exon 14 or less common mutations in exon 12. The landmark discovery of the autonomously activated JAK/STAT signaling pathway paved the way for the clinical development of the first target drug, the JAK1 and JAK2 inhibitor ruxolitinib. This is now approved for patients with resistance or intolerance to hydroxyurea. Phlebotomies and hydroxyurea are still the cornerstone of treatment, and aim to prevent the first appearance or recurrence of cardiovascular events that, together with progression to post-polycythemia vera myelofibrosis and leukemia, represent the main causes of death. Interferon-α is an alternative drug and has been shown to induce molecular remissions. It is currently undergoing phase III trials that might eventually lead to its approval for clinical use. The last few years have witnessed important advances towards an accurate early diagnosis of polycythemia vera, greater understanding of its pathogenesis, and improved patient management. This review will focus on the most recent achievements and will aim to unify the different concepts involved in a personalized approach to the patient with polycythemia vera. In spite of many recent advances in the understanding of its pathogenesis and improved disease management, polycythemia vera remains a life-threatening myeloproliferative neoplasm for which there is no cure. This review will present a critical overview of evolving concepts in diagnosis and treatment of this disease. Copyright© Ferrata Storti Foundation.

Molecular cloning and heterologous expression of a biosynthetic gene cluster for the antitubercular agent D-cycloserine produced by Streptomyces lavendulae.

PubMed

Kumagai, Takanori; Koyama, Yusuke; Oda, Kosuke; Noda, Masafumi; Matoba, Yasuyuki; Sugiyama, Masanori

2010-03-01

In the present study, we successfully cloned a 21-kb DNA fragment containing a d-cycloserine (DCS) biosynthetic gene cluster from a DCS-producing Streptomyces lavendulae strain, ATCC 11924. The putative gene cluster consists of 10 open reading frames (ORFs), designated dcsA to dcsJ. This cluster includes two ORFs encoding D-alanyl-D-alanine ligase (dcsI) and a putative membrane protein (dcsJ) as the self-resistance determinants of the producer organism, indicated by our previous work. When the 10 ORFs were introduced into DCS-nonproducing Streptomyces lividans 66 as a heterologous host cell, the transformant acquired DCS productivity. This reveals that the introduced genes are responsible for the biosynthesis of DCS. As anticipated, the disruption of dcsG, seen in the DCS biosynthetic gene cluster, made it possible for the strain ATCC 11924 to lose its DCS production. We here propose the DCS biosynthetic pathway. First, L-serine is O acetylated by a dcsE-encoded enzyme homologous to homoserine O-acetyltransferase. Second, O-acetyl-L-serine accepts hydroxyurea via an O-acetylserine sulfhydrylase homolog (dcsD product) and forms O-ureido-L-serine. The hydroxyurea must be supplied by the catalysis of a dcsB-encoded arginase homolog using the L-arginine derivative, N(G)-hydroxy-L-arginine. The resulting O-ureido-L-serine is then racemized to O-ureido-D-serine by a homolog of diaminopimelate epimerase. Finally, O-ureido-D-serine is cyclized to form DCS with the release of ammonia and carbon dioxide. The cyclization must be done by the dcsG or dcsH product, which belongs to the ATP-grasp fold family of protein.

Acute hemolytic vascular inflammatory processes are prevented by nitric oxide replacement or a single dose of hydroxyurea.

PubMed

Almeida, Camila Bononi; Souza, Lucas Eduardo Botelho; Leonardo, Flavia Costa; Costa, Fabio Trindade Maranhão; Werneck, Claudio C; Covas, Dimas Tadeu; Costa, Fernando Ferreira; Conran, Nicola

2015-08-06

Hemolysis and consequent release of cell-free hemoglobin (CFHb) impair vascular nitric oxide (NO) bioavailability and cause oxidative and inflammatory processes. Hydroxyurea (HU), a common therapy for sickle cell disease (SCD), induces fetal Hb production and can act as an NO donor. We evaluated the acute inflammatory effects of intravenous water-induced hemolysis in C57BL/6 mice and determined the abilities of an NO donor, diethylamine NONOate (DEANO), and a single dose of HU to modulate this inflammation. Intravenous water induced acute hemolysis in C57BL/6 mice, attaining plasma Hb levels comparable to those observed in chimeric SCD mice. This hemolysis resulted in significant and rapid systemic inflammation and vascular leukocyte recruitment within 15 minutes, accompanied by NO metabolite generation. Administration of another potent NO scavenger (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) to C57BL/6 mice induced similar alterations in leukocyte recruitment, whereas hemin-induced inflammation occurred over a longer time frame. Importantly, the acute inflammatory effects of water-induced hemolysis were abolished by the simultaneous administration of DEANO or HU, without altering CFHb, in an NO pathway-mediated manner. In vitro, HU partially reversed the Hb-mediated induction of endothelial proinflammatory cytokine secretion and adhesion molecule expression. In summary, pathophysiological levels of hemolysis trigger an immediate inflammatory response, possibly mediated by vascular NO consumption. HU presents beneficial anti-inflammatory effects by inhibiting rapid-onset hemolytic inflammation via an NO-dependent mechanism, independently of fetal Hb elevation. Data provide novel insights into mechanisms of hemolytic inflammation and further support perspectives for the use of HU as an acute treatment for SCD and other hemolytic disorders. © 2015 by The American Society of Hematology.

Selected terpenes from leaves of Ocimum basilicum L. induce hemoglobin accumulation in human K562 cells.

PubMed

Feriotto, Giordana; Marchetti, Nicola; Costa, Valentina; Torricelli, Piera; Beninati, Simone; Tagliati, Federico; Mischiati, Carlo

2018-06-01

Re-expression of fetal hemoglobin (HbF) was proposed as a possible therapeutic strategy for β-haemoglobinopathies. Although several inducers of HbF were tested in clinical trials, only hydroxyurea (HU) received FDA approval. Despite it produced adequate HbF levels only in half of HU-treated SCD patients, and was ineffective at all in β-thalassemia patients, beneficial effects of this approach suggested to continue in this direction identifying further molecules capable of inducing HbF. We tested the potential of essential oil isolated from Ocimum basilicum L. leaves (ObEO) in inducing hemoglobin biosynthesis. Initially, dose-dependent effect and kinetics of hemoglobin accumulation in K562 cells after treatment with ObEO were evaluated. ObEO induced dose-dependent hemoglobin accumulation superior to hydroxyurea and rapamycin and a strongest γ-globin mRNA expression. Terpenes composition of ObEO was studied by GC-MS. Three main constituents, linalool, eugenol and eucalyptol, represented about 75% of total. A blend of these three terpenes fully replicated the ObEO's biological effect, thus indicating that one of them or all together could be the active ingredients. When terpenes were tested individually, eugenol was the only one inducing stable hemoglobin accumulation, while eucalyptol and linalool produced only a small transient response. However, eugenol potential was strongly enhanced in the presence of eucalyptol and linalool, suggesting a synergistic effect on hemoglobin accumulation. By these results, the discovery of a new inducer and the interesting activity of a blend of major terpenes from ObOE on Hb accumulation could have positive fallouts on β-thalassemia and sickle cells anemia. Copyright © 2018 Elsevier B.V. All rights reserved.

Hydroxyurea Treatment and Development of the Rat Cerebellum: Effects on the Neurogenetic Profiles and Settled Patterns of Purkinje Cells and Deep Cerebellar Nuclei Neurons.

PubMed

Martí, Joaquín; Santa-Cruz, M C; Serra, Roger; Hervás, José P

2016-11-01

The current paper analyzes the development of the male and female rat cerebellum exposed to hydroxyurea (HU) (300 or 600 mg/kg) as embryo and collected at postnatal day 90. Our study reveals that the administration of this drug compromises neither the cytoarchitecture of the cerebellar cortex nor deep nuclei (DCN). However, in comparison with the saline group, we observed that several cerebellar parameters were lower in the HU injected groups. These parameters included area of the cerebellum, cerebellar cortex length, molecular layer area, Purkinje cell number, granule cell counts, internal granular layer, white matter and cerebellar nuclei areas, and number of deep cerebellar nuclei neurons. These features were larger in the rats injected with saline, smaller in those exposed to 300 mg/kg of HU and smallest in the group receiving 600 mg/kg of this agent. No sex differences in the effect of the HU were observed. In addition, we infer the neurogenetic timetables and the neurogenetic gradients of PCs and DCN neurons in rats exposed to either saline or HU as embryos. For this purpose, 5-bromo-2'-deoxyuridine was injected into pregnant rats previously administered with saline or HU. This thymidine analog was administered following a progressively delayed cumulative labeling method. The data presented here show that systematic differences exist in the pattern of neurogenesis and in the spatial location of cerebellar neurons between rats injected with saline or HU. No sex differences in the effect of the HU were observed. These findings have implications for the administration of this compound to women in gestation as the effects of HU on the development of the cerebellum might persist throughout their offsprings' life.

Sequential Oral Hydroxyurea and Intravenous Cytosine Arabinoside in Refractory Childhood Acute Leukemia: A Pediatric Oncology Group Phase I Study

PubMed Central

Dubowy, Ronald; Graham, Michael; Hakami, Nasrollah; Kletzel, Morris; Mahoney, Donald; Newman, Edward; Ravindranath, Yaddanapudi; Camitta, Bruce

2015-01-01

Summary At concentrations >0.1 mM, Hydroxyurea (HU) enhances the accumulation of cytosine arabinoside (ara-C) in leukemia cells in vitro. This study of children with refractory acute leukemia was designed to take advantage of this biochemical modulation. A fixed dose of HU and an escalating dose of ara-C were used. Oral HU, 1200 mg/m2 was followed 2 hours later by ara-C, 250-3100 mg/m2 intravenously in 15 minutes. The combination was given on days 1,2,3 and 8,9,10. Thirty-three children (26 ALL, 7 ANLL) were treated; 29 received at least one full course. All patients developed grade 4 cytopenias. Other grade 3-4 toxicities included: hyperbilirubinemia (2), elevated transaminases (3), transient gait disturbance (1), stomatitis (3), typhlitis (1), nausea/vomiting (9) and marrow aplasia >4 weeks (1). Three patients had intracranial bleeds while thrombocytopenic. Only liver toxicities and nausea/vomiting exhibited any dosage effect. The maximum tolerated dose of ara-C was 2400 mg/m2. There were 6 complete responses (5ALL), 5 partial responses (3 ALL), and 19 patients with no response or progressive disease. There was no dosage effect for response with 2 complete responses occurring at the lowest ara-C level. Responses were transient (1-3 months). 20/26 patients achieved a peak serum HU level >0.5 mM by 2 hours after the HU dose. The mean level at 2 hours was 0.57 mM (range 0.21-0.99 mM). This combination of HU and ara-C is tolerable and has efficacy in refractory leukemias. Responses at the lowest ara-C dose level suggests synergism. PMID:18458568

Sequential oral hydroxyurea and intravenous cytosine arabinoside in refractory childhood acute leukemia: a pediatric oncology group phase 1 study.

PubMed

Dubowy, Ronald; Graham, Michael; Hakami, Nasrollah; Kletzel, Morris; Mahoney, Donald; Newman, Edward; Ravindranath, Yaddanapudi; Camitta, Bruce

2008-05-01

At concentrations >0.1 mM, hydroxyurea (HU) enhances the accumulation of cytosine arabinoside (ara-C) in leukemia cells in vitro. This study of children with refractory acute leukemia was designed to take advantage of this biochemical modulation. A fixed dose of HU and an escalating dose of ara-C were used. Oral HU (1200 mg/m2) was followed 2 hours later by ara-C (250-3100 mg/m2) intravenously in 15 minutes. The combination was given on days 1, 2, 3 and 8, 9, 10. Thirty-three children [26 acute lymphocytic leukemia (ALL), 7 acute nonlymphocytic leukemia] were treated; 29 received at least 1 full course. All patients developed grade 4 cytopenias. Other grade 3 to 4 toxicities included hyperbilirubinemia (2), elevated transaminases (3), transient gait disturbance (1), stomatitis (3), typhlitis (1), nausea/vomiting (9), and marrow aplasia >4 weeks (1). Three patients had intracranial bleeds while thrombocytopenic. Only liver toxicities and nausea/vomiting exhibited any dosage effect. The maximum tolerated dose of ara-C was 2400 mg/m2. There were 6 complete responses (5 ALL), 5 partial responses (3 ALL), and 19 patients with no response or progressive disease. There was no dosage effect for response with 2 complete responses occurring at the lowest ara-C level. Responses were transient (1 to 3 mo). Twenty of twenty-six patients achieved a peak serum HU level >0.5 mM by 2 hours after the HU dose. The mean level at 2 hours was 0.57 mM (range: 0.21 to 0.99 mM). This combination of HU and ara-C is tolerable and has efficacy in refractory leukemias. Responses at the lowest ara-C dose level suggests synergism.

Hydroxyurea Induces Cytokinesis Arrest in Cells Expressing a Mutated Sterol-14α-Demethylase in the Ergosterol Biosynthesis Pathway.

PubMed

Xu, Yong-Jie; Singh, Amanpreet; Alter, Gerald M

2016-11-01

Hydroxyurea (HU) has been used for the treatment of multiple diseases, such as cancer. The therapeutic effect is generally believed to be due to the suppression of ribonucleotide reductase (RNR), which slows DNA polymerase movement at replication forks and induces an S phase cell cycle arrest in proliferating cells. Although aberrant mitosis and DNA damage generated at collapsed forks are the likely causes of cell death in the mutants with defects in replication stress response, the mechanism underlying the cytotoxicity of HU in wild-type cells remains poorly understood. While screening for new fission yeast mutants that are sensitive to replication stress, we identified a novel mutation in the erg11 gene encoding the enzyme sterol-14α-demethylase in the ergosterol biosynthesis pathway that dramatically sensitizes the cells to chronic HU treatment. Surprisingly, HU mainly arrests the erg11 mutant cells in cytokinesis, not in S phase. Unlike the reversible S phase arrest in wild-type cells, the cytokinesis arrest induced by HU is relatively stable and occurs at low doses of the drug, which likely explains the remarkable sensitivity of the mutant to HU. We also show that the mutation causes sterol deficiency, which may predispose the cells to the cytokinesis arrest and lead to cell death. We hypothesize that in addition to the RNR, HU may have a secondary unknown target(s) inside cells. Identification of such a target(s) may greatly improve the chemotherapies that employ HU or help to expand the clinical usage of this drug for additional pathological conditions. Copyright © 2016 by the Genetics Society of America.

Decreased fetal hemoglobin over time among youth with sickle cell disease on hydroxyurea is associated with higher urgent hospital use.

PubMed

Green, Nancy S; Manwani, Deepa; Qureshi, Mahvish; Ireland, Karen; Sinha, Arpan; Smaldone, Arlene M

2016-12-01

Hydroxyurea (HU) induces dose-dependent increased fetal hemoglobin (HbF) for sickle cell disease (SCD). Large deviation from historical personal best (PBest) HbF, a clinic-based version of maximum dose, may identify a subset with suboptimal HU adherence over time. Retrospective clinical data from youth ages 10-18 years prescribed HU at two centers were extracted from medical records at three time points: pre-HU initiation, PBest and a recent assessment. Decrease from PBest HbF of 20% or more at recent assessment despite stable dosing was designated as high deviation from PBest. Acute hospital use was compared between 1-year periods, pre-HU and ±6 months for PBest and recent assessment. Groups were compared using descriptive and bivariate nonparametric statistics. Seventy-five youth, mean HU duration 5.9 years, met eligibility criteria. Mean ages of HU initiation, PBest and recent assessment were 8.0, 10.9 and 13.9 years, respectively. Despite stable dosing, average HbF of 19.5% at PBest overall declined by 31.8% at recent assessment. PBest HbF declined by 11.7 and 40.1% in two groups, the latter comprised 70.7% of the sample, had lower pre-HU and recent HbF and higher dosing. They experienced more urgent hospital use during the year framing recent assessment than during PBest; these findings were supported by sensitivity analysis. Decline from PBest HbF is a novel approach to assess HU effectiveness, is common among youth and may represent suboptimal adherence. Larger prospective studies using additional adherence measures are needed to confirm our approach of tracking HbF deviation over time and to define an appropriate cutoff. © 2016 Wiley Periodicals, Inc.

Changes in urine albumin to creatinine ratio with the initiation of hydroxyurea therapy among children and adolescents with sickle cell disease.

PubMed

Tehseen, Sarah; Joiner, Clinton H; Lane, Peter A; Yee, Marianne E

2017-12-01

Renal damage is a progressive complication of sickle cell disease (SCD) that begins in childhood and may progress to renal failure and early mortality in 12% of adults with hemoglobin SS (HbSS) SCD. Early sickle nephropathy is characterized by hyperfiltration and microalbuminuria; therefore, urine albumin to creatinine ratio (ACR) is an effective screening tool for its detection. This study investigated the effect of hydroxyurea (HU) therapy on urine ACR levels among children with SCD. A retrospective review was conducted to identify all patients with HbSS or HbSβ 0 thalassemia of age 7-18 years who began HU therapy in 2011-2013; a control group of patients not on HU were matched by age and baseline hemoglobin. All urine ACR measurements ≤24 months prior to and ≥24 months after HU initiation were recorded. There were 63 eligible patients on HU and 13 (25%) with albuminuria prior to HU initiation. Among those with baseline albuminuria, the median ACR was 96 mg/g prior to HU, 39 mg/g at 1 year (P = 0.02), and 25 mg/g at 2 years (P = 0.03). Albuminuria normalized in 37.5% (6/16) after 1 year and 61% (8/13) after 2 years of HU therapy. Among those without albuminuria prior to HU, 13% (6/47) developed albuminuria during HU therapy. Sixteen percent (13/80) of control patients had albuminuria in the beginning of study period, which normalized in 15% (two of 13) of patients at 1-year follow up. Introduction of HU is associated with significant decreases in urine ACR in children with SCD and albuminuria. © 2017 Wiley Periodicals, Inc.

A reappraisal of the benefit-risk profile of hydroxyurea in polycythemia vera: A propensity-matched study.

PubMed

Barbui, Tiziano; Vannucchi, Alessandro Maria; Finazzi, Guido; Finazzi, Maria Chiara; Masciulli, Arianna; Carobbio, Alessandra; Ghirardi, Arianna; Tognoni, Gianni

2017-11-01

The use of hydroxyurea (HU) as first line therapy in polycythemia vera (PV) has been criticized because no solid demonstration that this drug prevents thrombosis or prolongs survival has been so far produced. Here we present the outcomes of a large cohort of patients with PV included in the European Collaborative Low-dose Aspirin (ECLAP) study. We selected 1,042 patients who, during the follow-up, had received only phlebotomy (PHL) or HU to maintain the hematocrit level < 45%. To assure comparability, we conducted a propensity score matching analysis. The two groups (PHL n = 342 and HU n = 681) were well balanced for the parameters included in the propensity score (overall balance: χ 2  = 2.44, P = 0.964). Over a comparable period of follow-up (PHL = 29.9 vs. HU = 34.7 months), we documented an advantage of HU over PHL consistently significant with respect to the incidence of fatal/non-fatal cardiovascular (CV) events (5.8 vs. 3.0 per 100 person-years in PHL vs. HU group, P = 0.002) and myelofibrosis transformation that was only experienced by patients of PHL group. Evolution to acute leukemia was registered in three patients (two in PHL and one in HU group). The excess of mortality and total CV events in the PHL patients was restricted to the high-risk group, and, compared with HU cases, was significant higher in the PHL patients who failed to reach the hematocrit target < 0.45% (P = 0.000). In conclusion, this analysis provides reliable and qualified estimates of the therapeutic profile of HU and PHL treatments for future experimental studies and for the management of PV in clinical practice. © 2017 Wiley Periodicals, Inc.

Randomized feasibility trial to improve hydroxyurea adherence in youth ages 10-18 years through community health workers: The HABIT study.

PubMed

Green, Nancy S; Manwani, Deepa; Matos, Sergio; Hicks, April; Soto, Luisa; Castillo, Yina; Ireland, Karen; Stennett, Yvonne; Findley, Sally; Jia, Haomiao; Smaldone, Arlene

2017-12-01

The main therapeutic intervention for sickle cell disease (SCD) is hydroxyurea (HU). The effect of HU is largely through dose-dependent induction of fetal hemoglobin (HbF). Poor HU adherence is common among adolescents. Our 6-month, two-site pilot intervention trial, "HABIT," was led by culturally aligned community health workers (CHWs). CHWs performed support primarily through home visits, augmented by tailored text message reminders. Dyads of youth with SCD ages 10-18 years and a parent were enrolled. A customized HbF biomarker, the percentage decrease from each patients' highest historical HU-induced HbF, "Personal best," was used to qualify for enrollment and assess HU adherence. Two primary outcomes were as follows: (1) intervention feasibility and acceptability and (2) HU adherence measured in three ways: monthly percentage improvement toward HbF Personal best, proportion of days covered (PDC) by HU, and self-report. Twenty-eight dyads were enrolled, of which 89% were retained. Feasibility and acceptability were excellent. Controlling for group assignment and month of intervention, the intervention group improved percentage decrease from Personal best by 2.3% per month during months 0-4 (P = 0.30), with similar improvement in adherence demonstrated using pharmacy records. Self-reported adherence did not correlate. Dyads viewed CHWs as supportive for learning about SCD and HU, living with SCD and making progress in coordinated self-management responsibility to support a daily HU habit. Most parents and youth appreciated text message HU reminders. The HABIT pilot intervention demonstrated feasibility and acceptability with promising effect toward improved medication adherence. Testing in a larger multisite intervention trial is warranted. © 2017 Wiley Periodicals, Inc.

Hydroxyurea with or without imatinib in the treatment of recurrent or progressive meningiomas: a randomized phase II trial by Gruppo Italiano Cooperativo di Neuro-Oncologia (GICNO).

PubMed

Mazza, Elena; Brandes, Alba; Zanon, Silvia; Eoli, Marika; Lombardi, Giuseppe; Faedi, Marina; Franceschi, Enrico; Reni, Michele

2016-01-01

Hydroxyurea (HU) is among the most widely used salvage therapies in progressive meningiomas. Platelet-derived growth factor receptors are expressed in virtually all meningiomas. Imatinib sensitizes transformed cells to the cytotoxic effects of chemotherapeutic agents that interfere with DNA metabolism. The combination of HU with imatinib yielded intriguing results in recurrent malignant glioma. The current trial addressed the activity of this association against meningioma. Patients with recurrent or progressive WHO grade I-III meningioma, without therapeutic indication for surgery, radiotherapy, or stereotactic radiosurgery, aged 18-75 years, ECOG performance status 0-2, and not on enzyme-inducing anti-epileptic drugs were randomized to receive HU 500 mg BID ± imatinib 400 mg QD until progression, unacceptable toxicity, or patient's refusal. The primary endpoint was progression-free survival rate at 9 months (PFS-9). Between September 2009 and February 2012, 15 patients were randomized to receive HU + imatinib (N = 7; Arm A) or HU alone (N = 8; Arm B). Afterward the trial was prematurely closed due to slow enrollment rate. PFS-9 (A/B) was 0/75%, and median PFS was 4/19.5 months. Median and 2-year overall survival (A/B) rates were: 6/27.5 months; 28.5/75%, respectively. Main G3-4 toxicities were: G3 neutropenia in 1/0, G4 headache in 1/1, and G3 vomiting in 1/0. The conduction of a study in recurrent or progressive meningioma remains a challenge. Given the limited number of patients enrolled, no firm conclusions can be drawn about the combination of imatinib and HU. The optimal systemic therapy for meningioma failing surgery and radiation has yet to be identified.

From leeches to personalized medicine: evolving concepts in the management of polycythemia vera

PubMed Central

Vannucchi, Alessandro M.

2017-01-01

Polycythemia vera is a clonal disorder of hematopoietic stem/progenitor cells. It manifests as an expansion of red cell mass. It is the most common chronic myeloproliferative neoplasm. In virtually all cases, it is characterized by a V617F point mutation in JAK2 exon 14 or less common mutations in exon 12. The landmark discovery of the autonomously activated JAK/STAT signaling pathway paved the way for the clinical development of the first target drug, the JAK1 and JAK2 inhibitor ruxolitinib. This is now approved for patients with resistance or intolerance to hydroxyurea. Phlebotomies and hydroxyurea are still the cornerstone of treatment, and aim to prevent the first appearance or recurrence of cardiovascular events that, together with progression to post-polycythemia vera myelofibrosis and leukemia, represent the main causes of death. Interferon-α is an alternative drug and has been shown to induce molecular remissions. It is currently undergoing phase III trials that might eventually lead to its approval for clinical use. The last few years have witnessed important advances towards an accurate early diagnosis of polycythemia vera, greater understanding of its pathogenesis, and improved patient management. This review will focus on the most recent achievements and will aim to unify the different concepts involved in a personalized approach to the patient with polycythemia vera. In spite of many recent advances in the understanding of its pathogenesis and improved disease management, polycythemia vera remains a life-threatening myeloproliferative neoplasm for which there is no cure. This review will present a critical overview of evolving concepts in diagnosis and treatment of this disease. PMID:27884974

Chronic transfusion practice for children with sickle cell anaemia and stroke.

PubMed

Aygun, Banu; McMurray, Marsha A; Schultz, William H; Kwiatkowski, Janet L; Hilliard, Lee; Alvarez, Ofelia; Heeney, Matthew; Kalinyak, Karen; Lee, Margaret T; Miller, Scott; Helms, Ronald W; Ware, Russell E

2009-05-01

Chronic transfusions to maintain haemoglobin S (HbS) < or =30% are the mainstay of treatment for children with sickle cell anaemia (SCA) and previous stroke. This HbS target is often hard to maintain, however, and values achieved in current practice are unknown. In preparation for the Phase III Stroke With Transfusions Changing to Hydroxyurea (SWiTCH) trial, we collected data on 295 children with SCA and stroke who received transfusions at 23 institutions. The overall average pre-transfusion %HbS was 35 +/- 11% (institutional range 22-51%). Receiving scheduled transfusions on time was the most predictive variable for maintaining HbS at the < or =30% goal.

Fatal Disseminated Tuberculosis during Treatment with Ruxolitinib Plus Prednisolone in a Patient with Primary Myelofibrosis: A Case Report and Review of the Literature.

PubMed

Tsukamoto, Yasuhiro; Kiyasu, Junichi; Tsuda, Mariko; Ikeda, Motohiko; Shiratsuchi, Motoaki; Ogawa, Yoshihiro; Yufu, Yuji

2018-05-01

A 73-year-old man with primary myelofibrosis (PMF) was being treated with hydroxyurea, which was changed to ruxolitinib treatment because of worsening constitutional symptoms. Although ruxolitinib rapidly induced relief, he developed a high-grade fever. A comprehensive fever work-up found no apparent cause of the fever, except for PMF. Therefore, we increased the dose of ruxolitinib and added prednisolone, which was gradually withdrawn with resolution of the fever. However, the patient subsequently developed disseminated tuberculosis and died eight months after initiation of ruxolitinib. Our case highlights the importance of assessing and monitoring the immune status of patients receiving ruxolitinib.

Therapeutic Phlebotomy is Safe in Children with Sickle Cell Anaemia and can be Effective Treatment for Transfusional Iron Overload

PubMed Central

Aygun, Banu; Mortier, Nicole A.; Kesler, Karen; Lockhart, Alexandre; Schultz, William H.; Cohen, Alan R.; Alvarez, Ofelia; Rogers, Zora R.; Kwiatkowski, Janet L.; Miller, Scott T.; Sylvestre, Pamela; Iyer, Rathi; Lane, Peter A.; Ware, Russell E.

2015-01-01

SUMMARY Serial phlebotomy was performed on sixty children with sickle cell anaemia, stroke and transfusional iron overload randomized to hydroxycarbamide in the Stroke With Transfusions Changing to Hydroxyurea trial. There were 927 phlebotomy procedures with only 33 adverse events, all of which were grade 2. Among 23 children completing 30 months of study treatment, the net iron balance was favourable (−8.7 mg Fe/kg) with significant decrease in ferritin, although liver iron concentration remained unchanged. Therapeutic phlebotomy was safe and well-tolerated, with net iron removal in most children who completed 30 months of protocol-directed treatment. PMID:25612463

Therapeutic phlebotomy is safe in children with sickle cell anaemia and can be effective treatment for transfusional iron overload.

PubMed

Aygun, Banu; Mortier, Nicole A; Kesler, Karen; Lockhart, Alexandre; Schultz, William H; Cohen, Alan R; Alvarez, Ofelia; Rogers, Zora R; Kwiatkowski, Janet L; Miller, Scott T; Sylvestre, Pamela; Iyer, Rathi; Lane, Peter A; Ware, Russell E

2015-04-01

Serial phlebotomy was performed on sixty children with sickle cell anaemia, stroke and transfusional iron overload randomized to hydroxycarbamide in the Stroke With Transfusions Changing to Hydroxyurea trial. There were 927 phlebotomy procedures with only 33 adverse events, all of which were grade 2. Among 23 children completing 30 months of study treatment, the net iron balance was favourable (-8·7 mg Fe/kg) with significant decrease in ferritin, although liver iron concentration remained unchanged. Therapeutic phlebotomy was safe and well-tolerated, with net iron removal in most children who completed 30 months of protocol-directed treatment. © 2015 John Wiley & Sons Ltd.

Hydroxycarbamine: from an Old Drug Used in Malignant Hemopathies to a Current Standard in Sickle Cell Disease

PubMed Central

Cannas, Giovanna; Poutrel, Solène; Thomas, Xavier

2017-01-01

While hydroxycarbamide (hydroxyurea, HU) has less and fewer indications in malignant hemopathies, it represents the only widely used drug which modifies sickle cell disease pathogenesis. Clinical experience with HU for patients with sickle cell disease has been accumulated over the past 25 years in Western countries. The review of the literature provides increasing support for safety and efficacy in both children and adults for reducing acute vaso-occlusive events including pain episodes and acute chest syndrome. No increased incidence of leukemia and teratogenicity was demonstrated. HU has become the standard-of-care for sickle cell anemia but remains underused. Barriers to its use should be identified and overcome. PMID:28293403

[A tamponade complicating an acute eosinophilic pericarditis due to a myeloproliferative/myelodysplastic syndrome].

PubMed

de Moreuil, C; Lieber, A; Marjanovic, Z; Bobbio, A; Alavi, Z; Blacher, J; Marie, J-P

2016-02-01

Cardiac involvement in eosinophilia is potentially fatal and requires early diagnosis and prompt treatment. We report here the case of a 71-year-old female patient with eosinophilia>10,000/mm(3) for 2 months due to a myeloproliferative/myelodysplastic syndrome, with a rapidly progressive exertional dyspnea explained by an important circumferential eosinophilic pericarditis. Due to a rapid evolution to a tamponade, an emergent surgical drainage was performed. Subsequent medical treatment combined high-dose corticosteroids (1mg/kg/day) with hydroxyurea and imatinib. The outcome was favourable with regression of the effusion, of the volume overload symptoms and decrease in eosinophilia. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Sickle cell disease in children.

PubMed

Meier, Emily Riehm; Miller, Jeffery L

2012-05-07

Early identification of infants with sickle cell disease (SCD) by newborn screening, now universal in all 50 states in the US, has improved survival, mainly by preventing overwhelming sepsis with the early use of prophylactic penicillin. Routine transcranial Doppler screening with the institution of chronic transfusion decreases the risk of stroke from 10% to 1% in paediatric SCD patients. Hydroxyurea decreases the number and frequency of painful crises, acute chest syndromes and number of blood transfusions in children with SCD. Genetic research continues to be driven toward the prevention and ultimate cure of SCD before adulthood. This review focuses on clinical manifestations and therapeutic strategies for paediatric SCD as well as the evolving topic of gene-focused prevention and therapy.

Effects of antineoplastic drugs on Lactobacillus casei and radioisotopic assays for serum folate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carmel, R.

1978-02-01

Microbiologic assay, usually employing Lactobacillus casei, remains the standard assay for serum folate to date. Among its disadvantages have been falsely low results in patients receiving bacteriostatic agents such as antibiotics. This study examined whether commonly used antineoplastic drugs had similar effect. Methotrexate and 5-fluorouracil depressed microbiologic serum folate levels. No effect was found for adriamycin, bleomycin, BCNU, cyclophosphamide, cytosine arabinoside, vincristine, vinblastine, mechlorethamine, mithramycin, hydroxyurea, and hydrocortisone. None of the drugs affected radioassay except methotrexate, which produced falsely high folate results. Thus, it appears that L. casei assay for folate becomes unreliable in patients receiving 5-fluorouracil and radioisotopic assaymore » becomes unreliable in those receiving methotrexate.« less

Clinical management of the hypereosinophilic syndromes.

PubMed

Cogan, Elie; Roufosse, Florence

2012-06-01

Hypereosinophilic syndromes (HESs) are rare disorders characterized by marked hypereosinophilia that is directly responsible for organ damage or dysfunction. Different pathogenic mechanisms have been discovered in patient subgroups leading to the characterization of myeloproliferative and lymphocytic disease variants. In the updated terminology, idiopathic HES is now restricted to patients with HES of undetermined etiology. The practical clinical approach of patients with the different HES variants is reviewed herein, focusing on specific diagnostic tools and therapeutic options. Corticosteroids, hydroxyurea and IFN-α remain the classical agents for treatment of most patients with HESs. The specific role of therapeutic compounds that have become available more recently, namely, tyrosine kinase inhibitors and IL-5 antagonists, is discussed.

The effect of DNA replication on mutation of the Saccharomyces cerevisiae CDC8 gene.

PubMed

Zaborowska, D; Zuk, J

1990-04-01

Incubation in YPD medium under permissive conditions when DNA replication is going on, strongly stimulates the induction of cdc+ colonies of UV-irradiated cells of yeast strains HB23 (cdc8-1/cdc8-3), HB26 (cdc8-3/cdc8-3) and HB7 (cdc8-1/cdc8-1). Inhibition of DNA replication by hydroxyurea, araCMP, cycloheximide or caffeine or else by incubation in phosphate buffer pH 7.0, abolishes this stimulation. Thus the replication of DNA is strongly correlated with the high induction of cdc+ colonies by UV irradiation. It is postulated that these UV-induced cdc+ colonies arise as the result infidelity in DNA replication.

Interventions for preventing silent cerebral infarcts in people with sickle cell disease

PubMed Central

Estcourt, Lise J; Fortin, Patricia M; Hopewell, Sally; Trivella, Marialena; Doree, Carolyn; Abboud, Miguel R

2017-01-01

Background Sickle cell disease (SCD) is one of the commonest severe monogenic disorders in the world, due to the inheritance of two abnormal haemoglobin (beta globin) genes. SCD can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Silent cerebral infarcts are the commonest neurological complication in children and probably adults with SCD. Silent cerebral infarcts also affect academic performance, increase cognitive deficits and may lower intelligence quotient. Objectives To assess the effectiveness of interventions to reduce or prevent silent cerebral infarcts in people with SCD. Search methods We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to 19 September 2016. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register: 06 October 2016. Selection criteria Randomised controlled trials comparing interventions to prevent silent cerebral infarcts in people with SCD. There were no restrictions by outcomes examined, language or publication status. Data collection and analysis We used standard Cochrane methodological procedures. Main results We included five trials (660 children or adolescents) published between 1998 and 2016. Four of the five trials were terminated early. The vast majority of participants had the haemoglobin (Hb)SS form of SCD. One trial focused on preventing silent cerebral infarcts or stroke; three trials were for primary stroke prevention and one trial dealt with secondary stroke prevention. Three trials compared the use of regular long-term red blood cell transfusions to standard care. Two of these trials included children with no previous long-term transfusions: one in children with normal transcranial doppler (TCD) velocities; and one in children with abnormal TCD velocities. The third trial included children and adolescents on long-term transfusion. Two trials compared the drug hydroxyurea and phlebotomy to long-term transfusions and iron chelation therapy: one in primary prevention (children), and one in secondary prevention (children and adolescents). The quality of the evidence was moderate to very low across different outcomes according to GRADE methodology. This was due to trials being at high risk of bias because they were unblinded; indirectness (available evidence was only for children with HbSS); and imprecise outcome estimates. Long-term red blood cell transfusions versus standard care Children with no previous long-term transfusions and higher risk of stroke (abnormal TCD velocities or previous history of silent cerebral infarcts) Long-term red blood cell transfusions may reduce the incidence of silent cerebral infarcts in children with abnormal TCD velocities, risk ratio (RR) 0.11 (95% confidence interval (CI) 0.02 to 0.86) (one trial, 124 participants, low-quality evidence); but make little or no difference to the incidence of silent cerebral infarcts in children with previous silent cerebral infarcts on magnetic resonance imaging and normal or conditional TCDs, RR 0.70 (95% CI 0.23 to 2.13) (one trial, 196 participants, low-quality evidence). No deaths were reported in either trial. Long-term red blood cell transfusions may reduce the incidence of: acute chest syndrome, RR 0.24 (95% CI 0.12 to 0.49) (two trials, 326 participants, low-quality evidence); and painful crisis, RR 0.63 (95% CI 0.42 to 0.95) (two trials, 326 participants, low-quality evidence); and probably reduces the incidence of clinical stroke, RR 0.12 (95% CI 0.03 to 0.49) (two trials, 326 participants, moderate-quality evidence). Long-term red blood cell transfusions may improve quality of life in children with previous silent cerebral infarcts (difference estimate -0.54; 95% confidence interval -0.92 to -0.17; one trial; 166 participants), but may have no effect on cognitive function (least squares means: 1.7, 95% CI -1.1 to 4.4) (one trial, 166 participants, low-quality evidence). Transfusions continued versus transfusions halted: children and adolescents with normalised TCD velocities (79 participants; one trial) Continuing red blood cell transfusions may reduce the incidence of silent cerebral infarcts, RR 0.29 (95% CI 0.09 to 0.97 (low-quality evidence). We are very uncertain whether continuing red blood cell transfusions has any effect on all-cause mortality, Peto odds ratio (OR) 8.00 (95% CI 0.16 to 404.12); or clinical stroke, RR 0.22 (95% CI 0.01 to 4.35) (very low-quality evidence). The trial did not report: comparative numbers for SCD-related adverse events; quality of life; or cognitive function. Hydroxyurea and phlebotomy versus transfusions and chelation Primary prevention, children (121 participants; one trial) We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: silent cerebral infarcts (no infarcts); all-cause mortality (no deaths); risk of stroke (no strokes); or SCD-related complications, RR 1.52 (95% CI 0.58 to 4.02) (very low-quality evidence). Secondary prevention, children and adolescents with a history of stroke (133 participants; one trial) We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: silent cerebral infarcts, Peto OR 7.28 (95% CI 0.14 to 366.91); all-cause mortality, Peto OR 1.02 (95% CI 0.06 to 16.41); or clinical stroke, RR 14.78 (95% CI 0.86 to 253.66) (very low-quality evidence). Switching to hydroxyurea and phlebotomy may increase the risk of SCD-related complications, RR 3.10 (95% CI 1.42 to 6.75) (low-quality evidence). Neither trial reported on quality of life or cognitive function. Authors’ conclusions We identified no trials for preventing silent cerebral infarcts in adults, or in children who do not have HbSS SCD. Long-term red blood cell transfusions may reduce the incidence of silent cerebral infarcts in children with abnormal TCD velocities, but may have little or no effect on children with normal TCD velocities. In children who are at higher risk of stroke and have not had previous long-term transfusions, long-term red blood cell transfusions probably reduce the risk of stroke, and other SCD-related complications (acute chest syndrome and painful crises). In children and adolescents at high risk of stroke whose TCD velocities have normalised, continuing red blood cell transfusions may reduce the risk of silent cerebral infarcts. No treatment duration threshold has been established for stopping transfusions. Switching to hydroxyurea with phlebotomy may increase the risk of silent cerebral infarcts and SCD-related serious adverse events in secondary stroke prevention. All other evidence in this review is of very low-quality. PMID:28500860

Pulmonary hypertension as a risk factor for death in patients with sickle cell disease.

PubMed

Gladwin, Mark T; Sachdev, Vandana; Jison, Maria L; Shizukuda, Yukitaka; Plehn, Jonathan F; Minter, Karin; Brown, Bernice; Coles, Wynona A; Nichols, James S; Ernst, Inez; Hunter, Lori A; Blackwelder, William C; Schechter, Alan N; Rodgers, Griffin P; Castro, Oswaldo; Ognibene, Frederick P

2004-02-26

The prevalence of pulmonary hypertension in adults with sickle cell disease, the mechanism of its development, and its prospective prognostic significance are unknown. We performed Doppler echocardiographic assessments of pulmonary-artery systolic pressure in 195 consecutive patients (82 men and 113 women; mean [+/-SD] age, 36+/-12 years). Pulmonary hypertension was prospectively defined as a tricuspid regurgitant jet velocity of at least 2.5 m per second. Patients were followed for a mean of 18 months, and data were censored at the time of death or loss to follow-up. Doppler-defined pulmonary hypertension occurred in 32 percent of patients. Multiple logistic-regression analysis, with the use of the dichotomous variable of a tricuspid regurgitant jet velocity of less than 2.5 m per second or 2.5 m per second or more, identified a self-reported history of cardiovascular or renal complications, increased systolic blood pressure, high lactate dehydrogenase levels (a marker of hemolysis), high levels of alkaline phosphatase, and low transferrin levels as significant independent correlates of pulmonary hypertension. The fetal hemoglobin level, white-cell count, and platelet count and the use of hydroxyurea therapy were unrelated to pulmonary hypertension. A tricuspid regurgitant jet velocity of at least 2.5 m per second, as compared with a velocity of less than 2.5 m per second, was strongly associated with an increased risk of death (rate ratio, 10.1; 95 percent confidence interval, 2.2 to 47.0; P<0.001) and remained so after adjustment for other possible risk factors in a proportional-hazards regression model. Pulmonary hypertension, diagnosed by Doppler echocardiography, is common in adults with sickle cell disease. It appears to be a complication of chronic hemolysis, is resistant to hydroxyurea therapy, and confers a high risk of death. Therapeutic trials targeting this population of patients are indicated. Copyright 2004 Massachusetts Medical Society

Biological impact of α genes, β haplotypes, and G6PD activity in sickle cell anemia at baseline and with hydroxyurea

PubMed Central

Arnaud, Cécile; Kamdem, Annie; Hau, Isabelle; Lelong, Françoise; Epaud, Ralph; Pondarré, Corinne; Pissard, Serge

2018-01-01

Sickle cell anemia (SCA), albeit monogenic, has heterogeneous phenotypic expression, mainly related to the level of hemoglobin F (HbF). No large cohort studies have ever compared biological parameters in patients with major β-globin haplotypes; ie, Senegal (SEN), Benin (BEN), and Bantu/Central African Republic (CAR). The aim of this study was to evaluate the biological impact of α genes, β haplotypes, and glucose-6-phosphate dehydrogenase (G6PD) activity at baseline and with hydroxyurea (HU). Homozygous HbS patients from the Créteil pediatric cohort with available α-gene and β-haplotype data were included (n = 580; 301 females and 279 males) in this retrospective study. Homozygous β-haplotype patients represented 74% of cases (37.4% CAR/CAR, 24.3% BEN/BEN, and 12.1% SEN/SEN). HU was given to 168 cohort SCA children. Hematological parameters were recorded when HbF was maximal, and changes (ΔHU-T0) were calculated. At baseline, CAR-haplotype and α-gene numbers were independently and negatively correlated with Hb and positively correlated with lactate dehydrogenase. HbF was negatively correlated with CAR-haplotype numbers and positively with BEN- and SEN-haplotype numbers. The BCL11A/rs1427407 “T” allele, which is favorable for HbF expression, was positively correlated with BEN- and negatively correlated with CAR-haplotype numbers. With HU treatment, Δ and HbF values were positively correlated with the BEN-haplotype number. BEN/BEN patients had higher HbF and Hb levels than CAR/CAR and SEN/SEN patients. In conclusion, we show that BEN/BEN patients have the best response on HU and suggest that this could be related to the higher prevalence of the favorable BCL11A/rs1427407/T/allele for HbF expression in these patients. PMID:29555644

Oxidant-antioxidant status in Egyptian children with sickle cell anemia: a single center based study.

PubMed

El-Ghamrawy, Mona Kamal; Hanna, Wagdi Maurice; Abdel-Salam, Amina; El-Sonbaty, Marwa M; Youness, Eman R; Adel, Ahmed

2014-01-01

the present study was conducted to investigate the oxidant-antioxidant status in Egyptian children with sickle cell anemia. the serum levels of total antioxidant capacity (TAO), paraoxonase (PON), vitamin E, nitrite, and malondialdehyde (MDA) were measured in 40 steady state children with homozygous sickle cell anemia (24 males and 16 females) and 20 apparently healthy age- and gender-matched controls. mean serum TAO, PON, vitamin E, and nitrite levels were significantly lower in the group with sickle cell anemia, whereas mean serum MDA was significantly higher in these children compared to controls. No significant differences in mean levels of TAO, PON, nitrite, vitamin E, and MDA were found in sickle cell anemia patients receiving hydroxyurea when compared with those not receiving hydroxyurea. A significant negative correlation between serum nitrite and the occurrence of vaso-occlusive crises (VOC) was observed (r=-0.3, p=0.04). PON level was found to be positively correlated with patients' weight and BMI (r=-0.4, p=0.01; r=-0.7, p<0.001, respectively), but not with frequency of VOC. The area under the curve of serum nitrite in predicting occurrence of VOC was 0.782, versus 0.701 for PON, and 0.650 for TAO (p=0.006). Serum MDA was not correlated with nitrite, PON, TAO, or vitamin E levels. No significant correlations were detected between serum nitrite and hemoglobin or antioxidant enzymes. children with sickle cell anemia have chronic oxidative stress that may result in increased VOC, and decreased serum nitrite may be associated with increases in VOC frequency. A novel finding in this study is the decrease in PON level in these patients, which is an interesting subject for further research. Copyright © 2014 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Soluble fms-Like Tyrosine Kinase 1 as a Link Between Angiogenesis and Endothelial Dysfunction in Pediatric Patients With β-Thalassemia Intermedia.

PubMed

Tantawy, Azza Abdel Gawad; Adly, Amira Abdel Moneam; Ismail, Eman Abdel Rahman; Youssef, Omneya Ibrahim; Ali, Mohamed ElSayed

2017-11-01

Endothelial damage has been implicated in the pathogenesis of vascular complications in β-thalassemia intermedia (β-TI). Soluble fms-like tyrosine kinase 1 (sFLT-1) is a member of the vascular endothelial growth factor receptor (VEGFR) family. Soluble fms-like tyrosine kinase 1 is an antiangiogenic protein that induces endothelial dysfunction by adhering to and inhibiting VEGF and placenta growth factor. The aim of this study was to assess the level of sFLT-1 in 35 children and adolescents with β-TI, correlating it with markers of hemolysis and iron overload as well as cardiopulmonary complications. Patients were studied focusing on the history of cardiac disease, splenectomy, transfusion, chelation/hydroxyurea therapy, serum ferritin, and sFLT-1 levels. Echocardiography and measurement of carotid intima-media thickness (CIMT) were done for all participants. Soluble fms-like tyrosine kinase 1 was significantly higher in TI patients compared to the control group (median [interquartile range], 110 [80-155] pg/mL versus 70 [60-90] pg/mL; P < .001). Splenectomized patients and those who had pulmonary hypertension risk or heart disease had higher sFLT-1 levels than those without ( P < .001). The sFLT-1 cutoff value that differentiates patients with and without pulmonary hypertension risk or heart disease was determined. Soluble fms-like tyrosine kinase 1 was lower among patients who received chelation therapy and/or hydroxyurea. Significant positive relations were observed between sFLT-1 and lactate dehydrogenase, serum ferritin, liver iron concentration, tricuspid regurgitant jet velocity, and CIMT. We suggest that sFLT-1 represents a link between angiogenesis, endothelial dysfunction, and subclinical atherosclerosis. Measurement of sFLT-1 as a marker of vascular dysfunction in β-TI may provide utility for early identification of patients at increased risk of cardiopulmonary complications.

Hydroxyurea lowers transcranial Doppler flow velocities in children with sickle cell anaemia in a Nigerian cohort.

PubMed

Lagunju, IkeOluwa; Brown, Biobele J; Sodeinde, Olugbemiro

2015-09-01

Sickle cell anaemia (SCA) is the leading genetic disorder in Nigeria. Elevated velocities ≥170 cm/sec occur in about a third of Nigerian children with SCA. Chronic blood transfusion for stroke prevention is faced with a myriad of challenges in our practice. To evaluate the effectiveness of hydroxyurea (HU) in reducing flow velocities in a cohort of Nigerian children with SCA and elevated velocities treated with HU. An observational study was carried out on a cohort of Nigerian children with SCA and elevated velocities identified on routine transcranial Doppler (TCD) screening. HU was recommended in those with TCD velocities ≥ 170cm/sec as stipulated in our hospital protocol. Outcomes were compared after ≥12 months of observation. Fifty children with elevated TCD velocities were studied; 31 consented to HU therapy and 19 declined. Children on HU showed a statistically significant decline in mean velocities from 199.7 [17.1] cm/sec to 165.8 [20.7] cm/sec (P < 0.001) with a significant increase in mean packed cell volume from 21.1 [3.4] to 25.0 [2.8]%. Children without treatment had a significant rise in mean velocities from 190.2 [10.8] cm/sec to 199.7 [14.9] cm/sec (P = 0.003). Children with conditional risk velocities on HU were less likely to convert to abnormal risk (P < 0.001). Two stroke events occurred, one in each group. No adverse effects of HU were recorded in the cohort. HU appears to significantly reduce TCD velocities in Nigerian children with SCA and elevated velocities ≥170 cm/sec with beneficial effect on the haematological profile. HU may provide an effective approach to primary stroke prevention, particularly in Africa. © 2015 Wiley Periodicals, Inc.

The unique stem cell system of the immortal larva of the human parasite Echinococcus multilocularis

PubMed Central

2014-01-01

Background It is believed that in tapeworms a separate population of undifferentiated cells, the germinative cells, is the only source of cell proliferation throughout the life cycle (similar to the neoblasts of free living flatworms). In Echinococcus multilocularis, the metacestode larval stage has a unique development, growing continuously like a mass of vesicles that infiltrate the tissues of the intermediate host, generating multiple protoscoleces by asexual budding. This unique proliferation potential indicates the existence of stem cells that are totipotent and have the ability for extensive self-renewal. Results We show that only the germinative cells proliferate in the larval vesicles and in primary cell cultures that undergo complete vesicle regeneration, by using a combination of morphological criteria and by developing molecular markers of differentiated cell types. The germinative cells are homogeneous in morphology but heterogeneous at the molecular level, since only sub-populations express homologs of the post-transcriptional regulators nanos and argonaute. Important differences are observed between the expression patterns of selected neoblast marker genes of other flatworms and the E. multilocularis germinative cells, including widespread expression in E. multilocularis of some genes that are neoblast-specific in planarians. Hydroxyurea treatment results in the depletion of germinative cells in larval vesicles, and after recovery following hydroxyurea treatment, surviving proliferating cells grow as patches that suggest extensive self-renewal potential for individual germinative cells. Conclusions In E. multilocularis metacestodes, the germinative cells are the only proliferating cells, presumably driving the continuous growth of the larval vesicles. However, the existence of sub-populations of the germinative cells is strongly supported by our data. Although the germinative cells are very similar to the neoblasts of other flatworms in function and in undifferentiated morphology, their unique gene expression pattern and the evolutionary loss of conserved stem cells regulators suggest that important differences in their physiology exist, which could be related to the unique biology of E. multilocularis larvae. PMID:24602211

Hydroxyurea and Zileuton Differentially Modulate Cell Proliferation and Interleukin-2 Secretion by Murine Spleen Cells: Possible Implication on the Immune Function and Risk of Pain Crisis in Patients with Sickle Cell Disease

PubMed Central

Kuvibidila, Solo; Warrier, Rajasekharan P.; Haynes, Johnson; Baliga, Surendra B.

2015-01-01

Background Hydroxyurea (HU) reduces major complications associated with sickle cell disease in part because of the induction of fetal hemoglobin. However, because of its antiproliferative property, its long-term use may impair immunity. Zileuton, a derivative of HU, also induces fetal hemoglobin and has antiinflammatory properties, a feature that can reduce the risk of sickling. Our goal was to investigate the capacity of both drugs to modulate the secretion of interleukin-2 (IL-2), a regulatory cytokine for immune responses. Methods Spleen cells obtained from 11 4-month-old C57BL/6 female mice were incubated without and with 10 μg/mL HU or zileuton, 2.5 μg/mL concanavalin A (ConA), 20 μg/mL phytohemagglutinin (PHA), and 50 ng/mL anti-CD3 antibody for 12-48 h. IL-2 was measured in the supernatant by enzyme-linked immunosorbent assay and cell proliferation by 3H-thymidine uptake. Results While HU reduced lymphocyte proliferation in response to mitogens (P<0.05), zileuton did not. Baseline IL-2 concentration and PHA-induced IL-2 were not significantly affected by either drug. Contrary to what we expected, while HU increased IL-2 supernatant levels 1.17-fold to 6.5-fold in anti-CD3 antibody–treated cells (P<0.05), zileuton decreased them 35%-65% (P<0.05). Zileuton likely reduced IL-2 levels by inhibiting 5-lipoxygenase, hence leukotriene B4 production, an IL-2 inducer. HU did not decrease IL-2 secretion likely because of its lack of effect on mRNA and protein synthesis. Conclusion Modulation of IL-2 secretion by zileuton and/or reduced lymphocyte proliferation by HU may impair the immune response of patients with sickle cell disease but may also be beneficial by attenuating inflammation independently of fetal hemoglobin induction. PMID:26412995

An altered REDOX environment, assisted by over-expression of fetal hemoglobins, protects from inflammatory colitis and reduces inflammatory cytokine expression.

PubMed

Gorczynski, R M; Alexander, C; Brandenburg, K; Chen, Z; Heini, A; Neumann, D; Mach, J P; Rietschel, E T; Tersikh, A; Ulmer, A J; Yu, Kai; Zahringer, U; Khatri, I

2017-09-01

C5BL/6 female mice receiving dextran sodium sulfate in their drinking water develop an acute inflammatory colitis within 7d, with weight loss, histopathologic signs of inflammation, and colonic expression of inflammatory cytokines. In previous studies we have reported that increased inflammatory cytokine expression in aged mice can be attenuated by oral gavage of a crude fetal extract containing glutathione (GSH), MPLA and fetal hemoglobin, or more specifically by injection of a combination of these purified reagents. We speculated that this combination led to an altered tissue redox environment in which the immune response developed, thus regulating inflammation. Accordingly, we used wild-type (WT) C57BL/6 mice, or mice lacking either murine beta Hemoglobin major (Hgbβ ma KO) or minor (Hgbβ mi KO) as recipients of DSS in their drinking water, and followed development of colitis both clinically and by inflammatory cytokine production, before/after oral treatment of mice with a crude fetal liver extract. Mice lacking an intact fetal hemoglobin chain (Hgbβ mi KO) developed severe colitis, with enhanced colonic expression of inflammatory cytokines, which could not be rescued by extract, unlike WT and Hgbβ ma KO animals. Moreover, disease in both WT and Hgbβ ma KO animals could also be attenuated by exposure to 5-hydroxymethyl furfural (5HMF), hydroxyurea or rapamycin. The former has been used as an alternative means of stabilizing the conformation of adult hemoglobin in a manner which mimicks the oxygen-affinity of fetal hemoglobin, while we show that both hydroxyurea and rapamycin augment expression of murine fetal hemoglobin chains. Our data suggests there may be a clinical value in exploring agents which alter local REDOX environments as an adjunctive treatment for colitis and attenuating inflammatory cytokine production. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of a hydroxyurea-resistant human KB cell line with supersensitivity to 6-thioguanine.

PubMed

Yen, Y; Grill, S P; Dutschman, G E; Chang, C N; Zhou, B S; Cheng, Y C

1994-07-15

Hydroxyurea (HU) is currently used in the clinic for the treatment of chronic myelogenous leukemia, head and neck carcinoma, and sarcoma. One of its drawbacks, however, is the development of HU resistance. To study this problem, we developed a HU-resistant human KB cell line which exhibits a 15-fold resistance to HU. The characterization of this HU-resistant phenotype revealed a gene amplification of the M2 subunit of ribonucleotide reductase (RR), increased levels of M2 mRNA and protein, and a 3-fold increase of RR activity. This HU-resistant cell line also expressed a "collateral sensitivity" to 6-thioguanine (6-TG), with a 10-fold decrease in the dose inhibiting cell growth by 50% as compared to the KB parental line. The mechanism responsible for this supersensitivity to 6-TG is believed to be related to an increasingly efficient conversion of 6-TG to its triphosphate form, which is subsequently incorporated into DNA. After passage of the resistant cells in the absence of HU, the cell line reverts. The revertant cells lose their resistance to HU and concomitantly their sensitivity to 6-TG. This phenomenon is due to the return of RR to levels comparable to that of the KB parental cell line. These observations and their relevance to cancer chemotherapy will be discussed in this paper. Our results suggest that a clinical protocol could be designed which would allow for a lower dose of 6-TG to be used by taking advantage of the increased RR activity in HU-refractory cancer patients. Two drugs which display collateral sensitivity are known as a "Ying-Yang" pair. Alternate treatment with two different Ying-Yang pairs is the rationale for the "Ying-Yang Ping-Pong" theory in cancer treatment. This rationale allows for effective cancer chemotherapy with reduced toxicity.

The unique stem cell system of the immortal larva of the human parasite Echinococcus multilocularis.

PubMed

Koziol, Uriel; Rauschendorfer, Theresa; Zanon Rodríguez, Luis; Krohne, Georg; Brehm, Klaus

2014-03-06

It is believed that in tapeworms a separate population of undifferentiated cells, the germinative cells, is the only source of cell proliferation throughout the life cycle (similar to the neoblasts of free living flatworms). In Echinococcus multilocularis, the metacestode larval stage has a unique development, growing continuously like a mass of vesicles that infiltrate the tissues of the intermediate host, generating multiple protoscoleces by asexual budding. This unique proliferation potential indicates the existence of stem cells that are totipotent and have the ability for extensive self-renewal. We show that only the germinative cells proliferate in the larval vesicles and in primary cell cultures that undergo complete vesicle regeneration, by using a combination of morphological criteria and by developing molecular markers of differentiated cell types. The germinative cells are homogeneous in morphology but heterogeneous at the molecular level, since only sub-populations express homologs of the post-transcriptional regulators nanos and argonaute. Important differences are observed between the expression patterns of selected neoblast marker genes of other flatworms and the E. multilocularis germinative cells, including widespread expression in E. multilocularis of some genes that are neoblast-specific in planarians. Hydroxyurea treatment results in the depletion of germinative cells in larval vesicles, and after recovery following hydroxyurea treatment, surviving proliferating cells grow as patches that suggest extensive self-renewal potential for individual germinative cells. In E. multilocularis metacestodes, the germinative cells are the only proliferating cells, presumably driving the continuous growth of the larval vesicles. However, the existence of sub-populations of the germinative cells is strongly supported by our data. Although the germinative cells are very similar to the neoblasts of other flatworms in function and in undifferentiated morphology, their unique gene expression pattern and the evolutionary loss of conserved stem cells regulators suggest that important differences in their physiology exist, which could be related to the unique biology of E. multilocularis larvae.

H2AX foci in late S/G2- and M-phase cells after hydroxyurea- and aphidicolin-induced DNA replication stress in Vicia.

PubMed

Rybaczek, Dorota; Bodys, Aleksandra; Maszewski, Janusz

2007-09-01

Immunocytochemistry using alpha-phospho-H2AX antibodies shows that hydroxyurea (HU), an inhibitor of ribonucleotide reductase, and aphidicolin (APH), an inhibitor of DNA-polymerases alpha and delta, may promote formation of phospho-H2AX foci in late S/G2-phase cells in root meristems of Vicia faba. Although fluorescent foci spread throughout the whole area of nucleoplasm, large phospho-H2AX aggregates in HU-treated cells allocate mainly in perinucleolar regions. A strong tendency of ATR/ATM-dependent phospho-Chk1S317 kinase to focus in analogous compartments, as opposed to phospho-Chk2T68 and to both effector kinases in APH-treated cells, may suggest that selected elements of the intra-S-phase cell cycle checkpoints share overlapping locations with DNA repair factors known to concentrate in phospho-H2AX aggregates. APH-induced phosphorylation of H2AX exhibits little or no overlap with the areas positioned close to nucleoli. Following G2-M transition of the HU- and APH-pretreated cells, altered chromatin structures are still discernible as large phospho-H2AX foci in the vicinity of chromosomes. Both in HU- and APH-treated roots, immunofluorescence analysis revealed a dominant fraction of small foci and a less frequent population of large phospho-H2AX aggregates, similar to those observed in animal cells exposed to ionizing radiation. The extent of H2AX phosphorylation has been found considerably reduced in root meristem cells treated with HU and caffeine. The frequencies of phospho-H2AX foci observed during mitosis and caffeine-mediated premature chromosome condensation (PCC) suggest that there may be functional links between the checkpoint mechanisms that control genome integrity and those activities which operate throughout the unperturbed mitosis in plants.

Comparison of hematologic measurements between local and central laboratories: data from the BABY HUG trial.

PubMed

Kalpatthi, Ram; Thompson, Bruce; Lu, Ming; Wang, Winfred C; Patel, Niren; Kutlar, Abdullah; Howard, Thomas; Luchtman-Jones, Lori; Miller, Scott T

2013-02-01

To investigate the concordance of blood count indices measured locally and at a central laboratory. In a multi-center clinical trial of hydroxyurea therapy in infants with sickle cell anemia (BABY HUG), the concordance between blood count indices measured locally and at a central laboratory was investigated. Local laboratory measurements of neutrophil and monocyte counts were significantly higher (44% and 37%, respectively) compared to the central measurements (p<0.0001), and mean corpuscular volume (MCV) was higher centrally. Overnight shipping with processing delay causes spurious reductions in absolute neutrophil count (ANC) and absolute monocyte count (AMC) that may result in incorrect monitoring decisions in multicenter clinical trials. Copyright © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Efficacy and Safety of Ruxolitinib in the Treatment of Patients with Myelofibrosis

PubMed Central

Yi, Cecilia Arana; Tam, Constantine S.; Verstovsek, Srdan

2016-01-01

The JAK 1 and JAK2 inhibitor ruxolitinib has approved indications in myelofibrosis, a BCR-ABL1-negative myeloproliferative neoplasm associated with progressive bone marrow fibrosis and shortened survival. In Phase III clinical studies, ruxolitinib provided rapid and durable improvement of myelofibrosis-related splenomegaly and symptoms irrespective of mutation status, and was associated with a survival advantage compared with placebo or best available therapy. Because of dose-dependent cytopenias, blood count monitoring and dose titration are important to optimize therapy. Specific precautions apply to the treatment of patients with or at risk of serious infections. Discontinuation of ruxolitinib generally leads to symptom return within 1 week. Ruxolitinib also is approved for treatment of patients with polycythemia vera who have had an inadequate response to or are intolerant of hydroxyurea. PMID:25757677

Ruxolitinib versus standard therapy for the treatment of polycythemia vera.

PubMed

Vannucchi, Alessandro M; Kiladjian, Jean Jacques; Griesshammer, Martin; Masszi, Tamas; Durrant, Simon; Passamonti, Francesco; Harrison, Claire N; Pane, Fabrizio; Zachee, Pierre; Mesa, Ruben; He, Shui; Jones, Mark M; Garrett, William; Li, Jingjin; Pirron, Ulrich; Habr, Dany; Verstovsek, Srdan

2015-01-29

Ruxolitinib, a Janus kinase (JAK) 1 and 2 inhibitor, was shown to have a clinical benefit in patients with polycythemia vera in a phase 2 study. We conducted a phase 3 open-label study to evaluate the efficacy and safety of ruxolitinib versus standard therapy in patients with polycythemia vera who had an inadequate response to or had unacceptable side effects from hydroxyurea. We randomly assigned phlebotomy-dependent patients with splenomegaly, in a 1:1 ratio, to receive ruxolitinib (110 patients) or standard therapy (112 patients). The primary end point was both hematocrit control through week 32 and at least a 35% reduction in spleen volume at week 32, as assessed by means of imaging. The primary end point was achieved in 21% of the patients in the ruxolitinib group versus 1% of those in the standard-therapy group (P<0.001). Hematocrit control was achieved in 60% of patients receiving ruxolitinib and 20% of those receiving standard therapy; 38% and 1% of patients in the two groups, respectively, had at least a 35% reduction in spleen volume. A complete hematologic remission was achieved in 24% of patients in the ruxolitinib group and 9% of those in the standard-therapy group (P=0.003); 49% versus 5% had at least a 50% reduction in the total symptom score at week 32. In the ruxolitinib group, grade 3 or 4 anemia occurred in 2% of patients, and grade 3 or 4 thrombocytopenia occurred in 5%; the corresponding percentages in the standard-therapy group were 0% and 4%. Herpes zoster infection was reported in 6% of patients in the ruxolitinib group and 0% of those in the standard-therapy group (grade 1 or 2 in all cases). Thromboembolic events occurred in one patient receiving ruxolitinib and in six patients receiving standard therapy. In patients who had an inadequate response to or had unacceptable side effects from hydroxyurea, ruxolitinib was superior to standard therapy in controlling the hematocrit, reducing the spleen volume, and improving symptoms associated with polycythemia vera. (Funded by Incyte and others; RESPONSE ClinicalTrials.gov number, NCT01243944.).

The subunits of the S-phase checkpoint complex Mrc1/Tof1/Csm3: dynamics and interdependence

PubMed Central

2014-01-01

Background The S-phase checkpoint aims to prevent cells from generation of extensive single-stranded DNA that predisposes to genome instability. The S. cerevisiae complex Tof1/Csm3/Mrc1 acts to restrain the replicative MCM helicase when DNA synthesis is prohibited. Keeping the replication machinery intact allows restart of the replication fork when the block is relieved. Although the subunits of the Tof1/Csm3/Mrc1 complex are well studied, the impact of every single subunit on the triple complex formation and function needs to be established. Findings This work studies the cellular localization and the chromatin binding of GFP-tagged subunits when the complex is intact and when a subunit is missing. We demonstrate that the complex is formed in cell nucleus, not the cytoplasm, as Tof1, Csm3 and Mrc1 enter the nucleus independently from one another. Via in situ chromatin binding assay we show that a Tof1-Csm3 dimer formation and chromatin binding is required to ensure the attachment of Mrc1 to chromatin. Our study indicates that the translocation into the nucleus is not the process to regulate the timing of chromatin association of Mrc1. We also studied the nuclear behavior of Mrc1 subunit in the process of adaptation to the presence hydroxyurea. Our results indicate that after prolonged HU incubation, cells bypass the S-phase checkpoint and proceed throughout the cell cycle. This process is accompanied by Mrc1 chromatin detachment and Rad53 dephosphorylation. Conclusions In S. cerevisiae the subunits of the S-phase checkpoint complex Mrc1/Tof1/Csm3 independently enter the cell nucleus, where a Tof1-Csm3 dimer is formed to ensure the chromatin binding of Mrc1 and favor DNA replication and S-phase checkpoint fork arrest. In the process of adaptation to the presence of hydroxyurea Mrc1 is detached from chromatin and Rad53 checkpoint activity is diminished in order to allow S-phase checkpoint escape and completion of the cell cycle. PMID:25379053

The subunits of the S-phase checkpoint complex Mrc1/Tof1/Csm3: dynamics and interdependence.

PubMed

Uzunova, Sonya Dimitrova; Zarkov, Alexander Stefanov; Ivanova, Anna Marianova; Stoynov, Stoyno Stefanov; Nedelcheva-Veleva, Marina Nedelcheva

2014-01-01

The S-phase checkpoint aims to prevent cells from generation of extensive single-stranded DNA that predisposes to genome instability. The S. cerevisiae complex Tof1/Csm3/Mrc1 acts to restrain the replicative MCM helicase when DNA synthesis is prohibited. Keeping the replication machinery intact allows restart of the replication fork when the block is relieved. Although the subunits of the Tof1/Csm3/Mrc1 complex are well studied, the impact of every single subunit on the triple complex formation and function needs to be established. This work studies the cellular localization and the chromatin binding of GFP-tagged subunits when the complex is intact and when a subunit is missing. We demonstrate that the complex is formed in cell nucleus, not the cytoplasm, as Tof1, Csm3 and Mrc1 enter the nucleus independently from one another. Via in situ chromatin binding assay we show that a Tof1-Csm3 dimer formation and chromatin binding is required to ensure the attachment of Mrc1 to chromatin. Our study indicates that the translocation into the nucleus is not the process to regulate the timing of chromatin association of Mrc1. We also studied the nuclear behavior of Mrc1 subunit in the process of adaptation to the presence hydroxyurea. Our results indicate that after prolonged HU incubation, cells bypass the S-phase checkpoint and proceed throughout the cell cycle. This process is accompanied by Mrc1 chromatin detachment and Rad53 dephosphorylation. In S. cerevisiae the subunits of the S-phase checkpoint complex Mrc1/Tof1/Csm3 independently enter the cell nucleus, where a Tof1-Csm3 dimer is formed to ensure the chromatin binding of Mrc1 and favor DNA replication and S-phase checkpoint fork arrest. In the process of adaptation to the presence of hydroxyurea Mrc1 is detached from chromatin and Rad53 checkpoint activity is diminished in order to allow S-phase checkpoint escape and completion of the cell cycle.

World Health Organization-defined eosinophilic disorders: 2017 update on diagnosis, risk stratification, and management.

PubMed

Gotlib, Jason

2017-11-01

The eosinophilias encompass a broad range of nonhematologic (secondary or reactive) and hematologic (primary, clonal) disorders with potential for end-organ damage. Hypereosinophilia has generally been defined as a peripheral blood eosinophil count greater than 1500/mm 3 and may be associated with tissue damage. After exclusion of secondary causes of eosinophilia, diagnostic evaluation of primary eosinophilias relies on a combination of morphologic review of the blood and marrow, standard cytogenetics, fluorescent in situ-hybridization, flow immunocytometry, and T-cell clonality assessment to detect histopathologic or clonal evidence for an acute or chronic myeloid or lymphoproliferative disorder. Disease prognosis relies on identifying the subtype of eosinophilia. After evaluation of secondary causes of eosinophilia, the 2016 World Health Organization endorses a semi-molecular classification scheme of disease subtypes which includes the major category "myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA, PDGFRB, or FGFR1 or with PCM1-JAK2," and the "MPN subtype, chronic eosinophilic leukemia, not otherwise specified" (CEL, NOS). Lymphocyte-variant hypereosinophilia is an aberrant T-cell clone-driven reactive eosinophila, and idiopathic hypereosinophilic syndrome (HES) is a diagnosis of exclusion. The goal of therapy is to mitigate eosinophil-mediated organ damage. For patients with milder forms of eosinophilia (e.g., < 1500/mm 3 ) without symptoms or signs of organ involvement, a watch and wait approach with close-follow-up may be undertaken. Identification of rearranged PDGFRA or PDGFRB is critical because of the exquisite responsiveness of these diseases to imatinib. Corticosteroids are first-line therapy for patients with lymphocyte-variant hypereosinophilia and HES. Hydroxyurea and interferon-alpha have demonstrated efficacy as initial treatment and steroid-refractory cases of HES. In addition to hydroxyurea, second line cytotoxic chemotherapy agents and hematopoietic cell transplant have been used for aggressive forms of HES and CEL with outcomes reported for limited numbers of patients. The use of antibodies against interleukin-5 (IL-5) (mepolizumab), the IL-5 receptor (benralizumab), and CD52 (alemtuzumab), as well as other targets on eosinophils remains an active area of investigation. © 2017 Wiley Periodicals, Inc.

Analysis of deoxyribonucleotide pools in human cancer cell lines using a liquid chromatography coupled with tandem mass spectrometry technique

PubMed Central

Zhang, Wei; Tan, Shenglan; Paintsil, Elijah; Dutschman, Ginger E.; Gullen, Elizabeth A.; Chu, Edward; Cheng, Yung-Chi

2011-01-01

Endogenous ribonucleotides and deoxyribonucleotides play a critical role in cell function, and determination of their levels is of fundamental importance in understanding key cellular processes involved in energy metabolism and molecular and biochemical signaling pathways. In this study, we determined the respective ribonucleotide and deoxyribonucleotide pool sizes in different human cell lines using a simple sample preparation method and LC/MS/MS. This assay was used to determine alterations in deoxyribonucleotide pools in human pancreatic PANC-1 cells in response to hypoxia and to treatment with either hydroxyurea or aphidicolin. The levels of all deoxyribonucleotide metabolites decreased with hypoxia treatment, except for dUMP, which increased by two-fold. This LC/MS/MS assay is simple, fast, and sensitive, and it represents a significant advance over previously published methodologies. PMID:21620803

Current Management of Sickle Cell Anemia

PubMed Central

McGann, Patrick T.; Nero, Alecia C.; Ware, Russell E.

2013-01-01

Proper management of sickle cell anemia (SCA) begins with establishing the correct diagnosis early in life, ideally during the newborn period. The identification of affected infants by neonatal screening programs allows early initiation of prophylactic penicillin and pneumococcal immunizations, which help prevent overwhelming sepsis. Ongoing education of families promotes the early recognition of disease-released complications, which allows prompt and appropriate medical evaluation and therapeutic intervention. Periodic evaluation by trained specialists helps provide comprehensive care, including transcranial Doppler examinations to identify children at risk for primary stroke, plus assessments for other parenchymal organ damage as patients become teens and adults. Treatment approaches that previously highlighted acute vaso-occlusive events are now evolving to the concept of preventive therapy. Liberalized use of blood transfusions and early consideration of hydroxyurea treatment represent a new treatment paradigm for SCA management. PMID:23709685

Rheumatoid Arthritis in Sickle-Cell Population: Pathophysiologic Insights, Clinical Evaluation and Management

PubMed Central

McFarlane, Isabel M; Ozeri, David J; Saperstein, Yair; Alvarez, Milena Rodriguez; Leon, Su Zhaz; Koci, Kristaq; Francis, Sophia; Singh, Soberjot; Salifu, Moro

2018-01-01

The advent of hydroxyurea and advanced medical care, including immunizations has led to improved survival among patients with Sickle Cell Disease (SCD). This prolonged survival however, introduces a chronic inflammatory disorder, Rheumatoid Arthritis (RA), which presents at a relatively older age and is rarely reported among SCD patients. In this review, we highlight the epidemiological association of SCD-RA and discuss the underlying common pathogenetic mechanisms, such as endothelial dysfunction, the role of inflammatory cytokines and oxidative stress. We also point to the difficulties in ascertaining the clinical diagnosis of RA in SCD patients. Finally, we provide rationale for therapeutic options available for RA and the challenges in the management of these patients with agents that are known to increase the risk of infection and immunosuppression such as steroids, disease modifying anti-rheumatic drugs and biologics. PMID:29375934

Analysis of mutagenic DNA repair in a thermoconditional mutant of Saccharomyces cerevisiae. IV. Influence of DNA replication and excision repair on REV2 dependent UV-mutagenesis and repair.

PubMed

Siede, W; Eckardt, F

1986-01-01

A double mutant being thermoconditionally defective in mutation induction as well as in repair of pre-lethal UV-induced DNA damage (rev2ts) and deficient in excision repair (rad3-2) was studied in temperature-shift experiments. The influence of inhibitors of DNA replication (hydroxyurea, aphidicolin) was determined. Additionally, an analysis of the dose-response pattern of mutation induction ("mutation kinetics") at several ochre alleles was carried out. It was concluded that the UV-inducible REV2 dependent mutagenic repair process is not induced in excision-deficient cells. In excision-deficient cells, REV2 dependent mutation fixation is slow and mostly post-replicative though not dependent on DNA replication. The REV2 mediated mutagenic process could be separated from the repair function.

Sickle Cell Disease with Cyanotic Congenital Heart Disease: Long-Term Outcomes in 5 Children.

PubMed

Iannucci, Glen J; Adisa, Olufolake A; Oster, Matthew E; McConnell, Michael; Mahle, William T

2016-12-01

Sickle cell disease is a risk factor for cerebrovascular accidents in the pediatric population. This risk is compounded by hypoxemia. Cyanotic congenital heart disease can expose patients to prolonged hypoxemia. To our knowledge, the long-term outcome of patients who have combined sickle cell and cyanotic congenital heart disease has not been reported. We retrospectively reviewed patient records at our institution and identified 5 patients (3 girls and 2 boys) who had both conditions. Their outcomes were uniformly poor: 4 died (age range, 12 mo-17 yr); 3 had documented cerebrovascular accidents; and 3 developed ventricular dysfunction. The surviving patient had developmental delays. On the basis of this series, we suggest mitigating hypoxemia, and thus the risk of stroke, in patients who have sickle cell disease and cyanotic congenital heart disease. Potential therapies include chronic blood transfusions, hydroxyurea, earlier surgical correction to reduce the duration of hypoxemia, and heart or bone marrow transplantation.

Proteomic analysis of the response to cell cycle arrests in human myeloid leukemia cells.

PubMed

Ly, Tony; Endo, Aki; Lamond, Angus I

2015-01-02

Previously, we analyzed protein abundance changes across a 'minimally perturbed' cell cycle by using centrifugal elutriation to differentially enrich distinct cell cycle phases in human NB4 cells (Ly et al., 2014). In this study, we compare data from elutriated cells with NB4 cells arrested at comparable phases using serum starvation, hydroxyurea, or RO-3306. While elutriated and arrested cells have similar patterns of DNA content and cyclin expression, a large fraction of the proteome changes detected in arrested cells are found to reflect arrest-specific responses (i.e., starvation, DNA damage, CDK1 inhibition), rather than physiological cell cycle regulation. For example, we show most cells arrested in G2 by CDK1 inhibition express abnormally high levels of replication and origin licensing factors and are likely poised for genome re-replication. The protein data are available in the Encyclopedia of Proteome Dynamics (

Characterization of the phase dependent pulmonary response following irritant inhalation exposure to nitrogen dioxide gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siegel, P.D.

1988-01-01

The present study utilized NO{sub 2} to fingerprint the biochemical reaction of the pulmonary compartment to oxidative damage and to correlate this with histopathology following acute and subacute exposures to NO{sub 2}. Acute exposure to NO{sub 2} produced dose-dependent immediate increases in the nonenzymatic parameters of pulmonary protein content, protease inhibitor activity and lung weight. The enzymatic activities of lactate dehydrogenase (LDH), choline kinase and beta-glucuronidase were elevated by two days following acute exposure. All of the above parameters were elevated following subacute exposure, however, nonenzymatic manifestations were attenuated with respect to enzymatic alterations. Hydroxyurea-induced granulocytopenia attenuated the increases inmore » activities of LDH and beta-glucuronidase following acute, but not subacute exposures. Cycloheximide-induced protein synthesis inhibition decrease the LDH and beta-glucuronidase response to NO{sub 2} without altering the increases in protein content or protease inhibitor activity.« less

Successful replantation of 2 digits in a patient with thrombocytosis after splenectomy: A case report.

PubMed

Hwang, Jae Ha; Kim, Dong Wan; Kim, Kwang Seog; Lee, Sam Yong

2018-06-01

Thrombosis is the most common complication of thrombocytosis, which can be particularly damaging to reattached digits. We present a guideline about digital replantation when thrombocytosis is expected. We report a case of an 18-year-old man who sustained a traumatic amputation of two fingers and splenic rupture in a traffic accident. He underwent digital replantation the day after splenectomy when life-threatening conditions had been managed. The platelet count increased to over 1,300,000/mm and post-splenectomy reactive thrombocytosis was diagnosed. Hydroxyurea and anagrelide were administered to control the platelet count after consultation with a hematologist. The reattached fingers survived without any complication. In patients with digital amputation, replantation can be attempted, even when thrombocytosis is expected, when requested by the patient. Furthermore, the platelet count should be actively controlled with medication to improve the survival rate of the reattached finger.

[Diagnosis and treatment of polycythaemia vera: state of the art].

PubMed

Marton, Imelda; Simon, Zsófia; Borbényi, Zita

2016-10-01

Polycythaemia vera (PV), a condition characterized by blood hyperviscosity due to the expansion of the erythrocyte mass is the most common entity among all Philadelphia chromosome-negative myeloproliferative neoplasms. Arterial and venous thrombotic events are leading determinants of morbidity and mortality but impairment of quality of life due to vasomotor symptoms (erythromelalgia, pruritus) and disease-associated symptoms (tiredness, fatigue, pruritus, night sweats, vision problems, headache, concentration loss, abdominal discomfort, early satiety, fever, weight loss) are also present. The review of polycythaemia vera is actual as the updated WHO 2016 classification of myeloid neoplasms has changed the diagnostic criteria and a new second-line treatment option - JAK1/JAK2 inhibitor ruxolitinib - has been approved for patients who had an inadequate response to or are intolerant of hydroxyurea, which represents a breakthrough in the treatment of this patient population. Orv. Hetil., 2016, 157(44), 1743-1751.

Characterization of MCSF-induced proliferation and subsequent osteoclast formation in murine marrow culture.

PubMed

Biskobing, D M; Fan, X; Rubin, J

1995-07-01

To clarify events involved in 1,25(OH)2D3-stimulated osteoclast-like cell (OCLC) formation in primary murine marrow culture, we have characterized kinetics of precursor proliferation and fusion and their dependence on macrophage colony-stimulating factor (MCSF). 3H-thymidine nuclear incorporation in tartrate-resistant acid phosphatase positive multinucleated cells (TRAP+ MNCs) was assessed: 3H-thymidine incorporation was greatest when tracer was added during day 4 or 5, with labeled nuclei in 81% (day 4) and 90% (day 5) of the TRAP+ MNCs counted at the end of day 7. The percentage of total nuclei labeled was highest when 3H-thymidine was dosed on day 4 (58%), decreasing to 2% by day 7. Final TRAP+ MNC numbers were depleted by 80% when treated for 24 h with hydroxyurea on either day 3 or 4; this inhibition dropped to 57% and 12% when hydroxyurea was pulsed during days 5 or 6, respectively. The absence of 1,25(OH)2D3 during days 1-4 caused 70% attenuation of TRAP+ MNC formation; however, exposure to 3H-thymidine during day 4 in this experiment resulted in subsequent labeling of 81% of the TRAP+ MNCs formed, indicating that precursor proliferation occurred in the absence of 1,25(OH)2D3. To demonstrate that proliferation required MCSF, cultures were exposed to a monoclonal anti-MCSF antibody during days 3, 4, 5, 6, or 7. Inhibition of TRAP+ MNC formation was 85% when antibody was added during day 3. Antibody treatment after day 5 had little effect on the OCLC number. Fusion of precursors showed steady progression with OCLCs containing 4.8 +/- 0.3 nuclei at the end of day 4, 8.3 +/- 0.5 nuclei after day 5, 12.0 +/- 1.3 after day 6, and 13.7 +/- 1.5 at the end of day 7. This steady accretion of nuclei was unaffected by doses of MCSF antibody which blocked proliferation. In conclusion, we have shown that OCLCs arise from an MCSF-dependent expansion of the precursor pool occurring during days 3 and 4. Fusion of these precursors, which begins as proliferation diminishes, is able to progress in the presence of anti-MCSF antibody. These results should help refine the analysis of factors affecting proliferation and fusion of osteoclasts in murine marrow culture.

Hydroxycarbamide versus chronic transfusion for maintenance of transcranial doppler flow velocities in children with sickle cell anaemia-TCD With Transfusions Changing to Hydroxyurea (TWiTCH): a multicentre, open-label, phase 3, non-inferiority trial.

PubMed

Ware, Russell E; Davis, Barry R; Schultz, William H; Brown, R Clark; Aygun, Banu; Sarnaik, Sharada; Odame, Isaac; Fuh, Beng; George, Alex; Owen, William; Luchtman-Jones, Lori; Rogers, Zora R; Hilliard, Lee; Gauger, Cynthia; Piccone, Connie; Lee, Margaret T; Kwiatkowski, Janet L; Jackson, Sherron; Miller, Scott T; Roberts, Carla; Heeney, Matthew M; Kalfa, Theodosia A; Nelson, Stephen; Imran, Hamayun; Nottage, Kerri; Alvarez, Ofelia; Rhodes, Melissa; Thompson, Alexis A; Rothman, Jennifer A; Helton, Kathleen J; Roberts, Donna; Coleman, Jamie; Bonner, Melanie J; Kutlar, Abdullah; Patel, Niren; Wood, John; Piller, Linda; Wei, Peng; Luden, Judy; Mortier, Nicole A; Stuber, Susan E; Luban, Naomi L C; Cohen, Alan R; Pressel, Sara; Adams, Robert J

2016-02-13

For children with sickle cell anaemia and high transcranial doppler (TCD) flow velocities, regular blood transfusions can effectively prevent primary stroke, but must be continued indefinitely. The efficacy of hydroxycarbamide (hydroxyurea) in this setting is unknown; we performed the TWiTCH trial to compare hydroxyurea with standard transfusions. TWiTCH was a multicentre, phase 3, randomised, open-label, non-inferiority trial done at 26 paediatric hospitals and health centres in the USA and Canada. We enrolled children with sickle cell anaemia who were aged 4-16 years and had abnormal TCD flow velocities (≥ 200 cm/s) but no severe vasculopathy. After screening, eligible participants were randomly assigned 1:1 to continue standard transfusions (standard group) or hydroxycarbamide (alternative group). Randomisation was done at a central site, stratified by site with a block size of four, and an adaptive randomisation scheme was used to balance the covariates of baseline age and TCD velocity. The study was open-label, but TCD examinations were read centrally by observers masked to treatment assignment and previous TCD results. Participants assigned to standard treatment continued to receive monthly transfusions to maintain 30% sickle haemoglobin or lower, while those assigned to the alternative treatment started oral hydroxycarbamide at 20 mg/kg per day, which was escalated to each participant's maximum tolerated dose. The treatment period lasted 24 months from randomisation. The primary study endpoint was the 24 month TCD velocity calculated from a general linear mixed model, with the non-inferiority margin set at 15 cm/s. The primary analysis was done in the intention-to-treat population and safety was assessed in all patients who received at least one dose of assigned treatment. This study is registered with ClinicalTrials.gov, number NCT01425307. Between Sept 20, 2011, and April 17, 2013, 159 patients consented and enrolled in TWiTCH. 121 participants passed screening and were then randomly assigned to treatment (61 to transfusions and 60 to hydroxycarbamide). At the first scheduled interim analysis, non-inferiority was shown and the sponsor terminated the study. Final model-based TCD velocities were 143 cm/s (95% CI 140-146) in children who received standard transfusions and 138 cm/s (135-142) in those who received hydroxycarbamide, with a difference of 4·54 (0·10-8·98). Non-inferiority (p=8·82 × 10(-16)) and post-hoc superiority (p=0·023) were met. Of 29 new neurological events adjudicated centrally by masked reviewers, no strokes were identified, but three transient ischaemic attacks occurred in each group. Magnetic resonance brain imaging and angiography (MRI and MRA) at exit showed no new cerebral infarcts in either treatment group, but worsened vasculopathy in one participant who received standard transfusions. 23 severe adverse events in nine (15%) patients were reported for hydroxycarbamide and ten serious adverse events in six (10%) patients were reported for standard transfusions. The most common serious adverse event in both groups was vaso-occlusive pain (11 events in five [8%] patients with hydroxycarbamide and three events in one [2%] patient for transfusions). For high-risk children with sickle cell anaemia and abnormal TCD velocities who have received at least 1 year of transfusions, and have no MRA-defined severe vasculopathy, hydroxycarbamide treatment can substitute for chronic transfusions to maintain TCD velocities and help to prevent primary stroke. National Heart, Lung, and Blood Institute, National Institutes of Health. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Case of pediatric chronic myeloid leukemia with bilateral visual loss onset].

PubMed

Hara, Yusuke; Kamura, Yumi; Oikawa, Aki; Shichino, Hiroyuki; Mugishima, Hideo; Goto, Hiroshi

2010-05-01

Chronic myeloid leukemia (CML) during childhood is rare, and only been a few cases showed visual disturbances as an initial symptom. We report a pediatric CML case diagnosed by bilateral visual loss. An 11-year-old boy complained of visual loss in both eyes. His best corrected visual acuity was 0.5 in the right eye and 0.2 in the left. Fundus examination showed disc swelling, dilated and tortuous retinal veins and multiple elevated retinal lesions with hemorrhages of various size from one-forth to four disc diameters in both eyes. He was diagnosed as having CML by leucocytosis and systematic work-up including Philadelphia chromosome-positive, BCR-ABL kinase domain in peripheral blood and bone marrow. The ocular findings improved after treatment with hydroxyurea, leukocytaphresis and imatinib. His best corrected visual acuity improved to 0.7 in both eyes. Recent leukemia therapy including imatinib is effective not only for ocular lesions but also to induce hematological remission in childhood CML.

Clinical Features of β-Thalassemia and Sickle Cell Disease.

PubMed

McGann, Patrick T; Nero, Alecia C; Ware, Russell E

2017-01-01

Sickle cell disease (SCD) and β-thalassemia are among the most common inherited diseases, affecting millions of persons globally. It is estimated that 5-7% of the world's population is a carrier of a significant hemoglobin variant. Without early diagnosis followed by initiation of preventative and therapeutic care, both SCD and β-thalassemia result in significant morbidity and early mortality. Despite great strides in the understanding of the molecular basis and pathophysiology of these conditions, the burden of disease remains high, particularly in limited resource settings. Current therapy relies heavily upon the availability and safety of erythrocyte transfusions to treat acute and chronic complications of these conditions, but frequent transfusions results in significant iron overload, as well as challenges from acquired infections and alloimmunization. Hydroxyurea is a highly effective treatment for SCD but less so for β-thalassemia, and does not represent curative therapy. As technology and use of cellular and gene therapies expand, SCD and thalassemia should be among the highest disease priorities.

Proteomic analysis of the response to cell cycle arrests in human myeloid leukemia cells

PubMed Central

Ly, Tony; Endo, Aki; Lamond, Angus I

2015-01-01

Abstract Previously, we analyzed protein abundance changes across a ‘minimally perturbed’ cell cycle by using centrifugal elutriation to differentially enrich distinct cell cycle phases in human NB4 cells (Ly et al., 2014). In this study, we compare data from elutriated cells with NB4 cells arrested at comparable phases using serum starvation, hydroxyurea, or RO-3306. While elutriated and arrested cells have similar patterns of DNA content and cyclin expression, a large fraction of the proteome changes detected in arrested cells are found to reflect arrest-specific responses (i.e., starvation, DNA damage, CDK1 inhibition), rather than physiological cell cycle regulation. For example, we show most cells arrested in G2 by CDK1 inhibition express abnormally high levels of replication and origin licensing factors and are likely poised for genome re-replication. The protein data are available in the Encyclopedia of Proteome Dynamics (http://www.peptracker.com/epd/), an online, searchable resource. DOI: http://dx.doi.org/10.7554/eLife.04534.001 PMID:25555159

PRIMARY STROKE PREVENTION IN CHILDREN WITH SICKLE CELL ANEMIA LIVING IN AFRICA: THE FALSE CHOICE BETWEEN PATIENT-ORIENTED RESEARCH AND HUMANITARIAN SERVICE

PubMed Central

DEBAUN, MICHAEL R.; GALADANCI, NAJIBAH A.; KASSIM, ADETOLA A.; JORDAN, LORI C.; PHILLIPS, SHARON; ALIYU, MUKTAR H.

2016-01-01

In the United States, primary stroke prevention in children with sickle cell anemia (SCA) is now the standard of care and includes annual transcranial Doppler ultrasound evaluation to detect elevated intracranial velocities; and for those at risk, monthly blood transfusion therapy for at least a year followed by the option of hydroxyurea therapy. This strategy has decreased stroke prevalence in children with SCA from approximately 11% to 1%. In Africa, where 80% of all children with SCA are born, no systematic approach exists for primary stroke prevention. The two main challenges for primary stroke prevention in children with SCA in Africa include: 1) identifying an alternative to blood transfusion therapy, because safe monthly blood transfusion therapy is not feasible; and 2) assembling a health care team to implement and expand this effort. We will emphasize early triumphs and challenges to decreasing the incidence of strokes in African children with SCA. PMID:28066035

Ruxolitinib: long-term management of patients with myelofibrosis and future directions in the treatment of myeloproliferative neoplasms.

PubMed

Yacoub, A; Odenike, O; Verstovsek, S

2014-12-01

Considerable clinical experience regarding the long-term efficacy and safety of ruxolitinib has been gathered since the drug was approved in the USA for patients with intermediate or high-risk myelofibrosis (MF) in November 2011. Findings from the pivotal phase 3 COMFORT studies showed that ruxolitinib-associated reductions in MF-related splenomegaly and symptom burden occur rapidly and in the majority of patients. Two- and 3-year follow-up data further suggest that the benefits of ruxolitinib are durable and associated with a survival advantage compared with conventional therapies. However, careful management of treatment-related thrombocytopenia and anemia with dose modifications and supportive care is critical to allow chronic therapy. Based on preliminary evidence, ruxolitinib also allows spleen size and symptom reduction before allogeneic stem cell transplantation without negative effect on engraftment or outcomes. In recent studies, ruxolitinib provided effective management of hematologic parameters and symptoms in patients with polycythemia vera refractory to or intolerant of hydroxyurea.

Patient-specific modeling and analysis of dynamic behavior of individual sickle red blood cells under hypoxic conditions

NASA Astrophysics Data System (ADS)

Li, Xuejin; Du, E.; Li, Zhen; Tang, Yu-Hang; Lu, Lu; Dao, Ming; Karniadakis, George

2015-11-01

Sickle cell anemia is an inherited blood disorder exhibiting heterogeneous morphology and abnormal dynamics under hypoxic conditions. We developed a time-dependent cell model that is able to simulate the dynamic processes of repeated sickling and unsickling of red blood cells (RBCs) under physiological conditions. By using the kinetic cell model with parameters derived from patient-specific data, we present a mesoscopic computational study of the dynamic behavior of individual sickle RBCs flowing in a microfluidic channel with multiple microgates. We investigate how individual sickle RBCs behave differently from healthy ones in channel flow, and analyze the alteration of cellular behavior and response to single-cell capillary obstruction induced by cell rheologic rigidification and morphological change due to cell sickling under hypoxic conditions. We also simulate the flow dynamics of sickle RBCs treated with hydroxyurea (HU) and quantify the relative enhancement of hemodynamic performance of HU. This work was supported by the National Institutes of Health (NIH) Grant U01HL114476.

Adenovirus type 2 DNA replication. I. Evidence for discontinuous DNA synthesis.

PubMed Central

Winnacker, E L

1975-01-01

Isolated nuclei from adenovirus type 2-infected HeLa cells catalyze the incorporation of all four deoxyribonucleoside triphosphates into viral DNA. The observed DNA synthesis occurs via a transient formation of DNA fragments with a sedimentation coefficient of 10S. The fragments are precursors to unit-length viral DNA, they are self-complementary to an extent of at least 70%, and they are distributed along most of the viral chromosome. In addition, accumulation of 10S DNA fragments is observed either in intact, virus-infected HeLa cells under conditions where viral DNA synthesis is inhibited by hydroxyurea or in isolated nuclei from virus-infected HeLa cells at low concentrations of deoxyribonucleotides. Under these suboptimal conditions for DNA synthesis in isolated nuclei, ribonucleoside triphosphates determine the size distribution of DNA intermediates. The evidence presented suggests that a ribonucleoside-dependent initiation step as well at two DNA polymerase catalyzed reactions are involved in the discontinuous replication of adenovirus type 2 DNA. PMID:1117487

Altruistic self-removal of health-compromised honey bee workers from their hive.

PubMed

Rueppell, O; Hayworth, M K; Ross, N P

2010-07-01

Social insect colonies represent distinct units of selection. Most individuals evolve by kin selection and forgo individual reproduction. Instead, they display altruistic food sharing, nest maintenance and self-sacrificial colony defence. Recently, altruistic self-removal of diseased worker ants from their colony was described as another important kin-selected behaviour. Here, we report corroborating experimental evidence from honey bee foragers and theoretical analyses. We challenged honey bee foragers with prolonged CO(2) narcosis or by feeding with the cytostatic drug hydroxyurea. Both treatments resulted in increased mortality but also caused the surviving foragers to abandon their social function and remove themselves from their colony, resulting in altruistic suicide. A simple model suggests that altruistic self-removal by sick social insect workers to prevent disease transmission is expected under most biologically plausible conditions. The combined theoretical and empirical support for altruistic self-removal suggests that it may be another important kin-selected behaviour and a potentially widespread mechanism of social immunity.

Bone marrow necrosis in a patient with acute promyelocytic leukemia during re-induction therapy with arsenic trioxide.

PubMed

Ishitsuka, Kenji; Shirahashi, Akihiko; Iwao, Yasuhiro; Shishime, Mikiko; Takamatsu, Yasushi; Takatsuka, Yoshifusa; Utsunomiya, Atae; Suzumiya, Junji; Hara, Syuji; Tamura, Kazuo

2004-04-01

Arsenic trioxide (As2O3) therapy at a daily dose of 0.15 mg/kg was given to a 60-yr-old Japanese male with refractory acute promyelocytic leukemia. White blood cell (WBC) of 6.6 x 10(3)/microl increased to 134 x 10(3)/microl following the administration of As2O3. Daily hydroxyurea (HU), and 6-mercaptopurine (6-MP) were added on days 7 and 19, respectively. Both HU and 6-MP were discontinued on day 28, when WBC declined to 54.0 x 10(3)/microl. He developed unexplained fever and profound cytopenia requiring multiple blood products transfusions. Bone marrow examination on day 42 revealed massive necrosis. Pharmacokinetics confirmed a mean maximum plasma arsenic concentration (Cpmax) and a half-life time (t1/2) of 6.9 microm and 3.2 h, respectively, in the therapeutic range. This is the first case of bone marrow necrosis after standard-dose As2O3 therapy.

Nuclear Mitochondrial DNA Activates Replication in Saccharomyces cerevisiae

PubMed Central

Chatre, Laurent; Ricchetti, Miria

2011-01-01

The nuclear genome of eukaryotes is colonized by DNA fragments of mitochondrial origin, called NUMTs. These insertions have been associated with a variety of germ-line diseases in humans. The significance of this uptake of potentially dangerous sequences into the nuclear genome is unclear. Here we provide functional evidence that sequences of mitochondrial origin promote nuclear DNA replication in Saccharomyces cerevisiae. We show that NUMTs are rich in key autonomously replicating sequence (ARS) consensus motifs, whose mutation results in the reduction or loss of DNA replication activity. Furthermore, 2D-gel analysis of the mrc1 mutant exposed to hydroxyurea shows that several NUMTs function as late chromosomal origins. We also show that NUMTs located close to or within ARS provide key sequence elements for replication. Thus NUMTs can act as independent origins, when inserted in an appropriate genomic context or affect the efficiency of pre-existing origins. These findings show that migratory mitochondrial DNAs can impact on the replication of the nuclear region they are inserted in. PMID:21408151

Chk1 and Wee1 kinases coordinate DNA replication, chromosome condensation, and anaphase entry

PubMed Central

Fasulo, Barbara; Koyama, Carol; Yu, Kristina R.; Homola, Ellen M.; Hsieh, Tao S.; Campbell, Shelagh D.; Sullivan, William

2012-01-01

Defects in DNA replication and chromosome condensation are common phenotypes in cancer cells. A link between replication and condensation has been established, but little is known about the role of checkpoints in monitoring chromosome condensation. We investigate this function by live analysis, using the rapid division cycles in the early Drosophila embryo. We find that S-phase and topoisomerase inhibitors delay both the initiation and the rate of chromosome condensation. These cell cycle delays are mediated by the cell cycle kinases chk1 and wee1. Inhibitors that cause severe defects in chromosome condensation and congression on the metaphase plate result in delayed anaphase entry. These delays are mediated by wee1 and are not the result of spindle assembly checkpoint activation. In addition, we provide the first detailed live analysis of the direct effect of widely used anticancer agents (aclarubicin, ICRF-193, VM26, doxorubicin, camptothecin, aphidicolin, hydroxyurea, cisplatin, mechlorethamine and x-rays) on key nuclear and cytoplasmic cell cycle events. PMID:22262459

[Sickle cell disease: from childhood to adolescence. Management in 2001].

PubMed

Bégué, P; Castello-Herbreteau, B

2001-05-01

Sickle cell anaemia is a chronic disease which evolves on the background of a basal state punctuated by critical periods, often with complications requiring overall treatment. The management of both periods must be well integrated into the treatment programme. In order to treat occlusive crisis, medical staff must be well trained and equipped for the complicated clinical diagnoses involved in drepanocytosis: bone infarction or osteomyelitis, pneumonia or acute chest syndrome, multifocal crisis or severe infectious disease. Neonatal diagnosis is the best way for early treatment by preventing severe pneumococcal diseases, ensuring sufficient hydration and appropriate surveillance, as well as providing family education. Much progress has been made over the last decade in the early treatment of retinitis, biliary lithiasis, and aseptic hip necrosis. It is also important to ensure accurate prescriptions for hydroxyurea. Specialised centres for drepanocytosis treatment are now a growing necessity and should be encouraged in order to provide treatment for dispersed patients against a relatively little known disease.

Treatment and management of myelofibrosis in the era of JAK inhibitors

PubMed Central

Keohane, Clodagh; Radia, Deepti H; Harrison, Claire N

2013-01-01

Myelofibrosis (MF) can present as a primary disorder or evolve from polycythemia vera (PV) or essential thrombocythemia (ET) to post-PV MF or post-ET MF, respectively. MF is characterized by bone marrow fibrosis, splenomegaly, leukoerythroblastosis, extramedullary hematopoiesis, and a collection of debilitating symptoms. Until recently, the therapeutic options for patients with MF consisted of allogeneic hematopoietic stem cell transplant (alloHSCT), the use of cytoreductive agents (ie, hydroxyurea), splenectomy and splenic irradiation for treatment of splenomegaly, and management of anemia with transfusions, erythropoiesis-stimulating agents (ESAs), androgens, and immunomodulatory agents. However, with increased understanding of the pathogenesis of MF resulting from dysregulated Janus kinase (JAK) signaling, new targeted JAK inhibitor therapies, such as ruxolitinib, are now available. The purpose of this article is to review the clinical features of MF, discuss the use and future of JAK inhibitors, reassess when and how to use conventional MF treatments in the context of JAK inhibitors, and provide a perspective on the future of MF treatment. PMID:23990704

Treatment and management of myelofibrosis in the era of JAK inhibitors.

PubMed

Keohane, Clodagh; Radia, Deepti H; Harrison, Claire N

2013-01-01

Myelofibrosis (MF) can present as a primary disorder or evolve from polycythemia vera (PV) or essential thrombocythemia (ET) to post-PV MF or post-ET MF, respectively. MF is characterized by bone marrow fibrosis, splenomegaly, leukoerythroblastosis, extramedullary hematopoiesis, and a collection of debilitating symptoms. Until recently, the therapeutic options for patients with MF consisted of allogeneic hematopoietic stem cell transplant (alloHSCT), the use of cytoreductive agents (ie, hydroxyurea), splenectomy and splenic irradiation for treatment of splenomegaly, and management of anemia with transfusions, erythropoiesis-stimulating agents (ESAs), androgens, and immunomodulatory agents. However, with increased understanding of the pathogenesis of MF resulting from dysregulated Janus kinase (JAK) signaling, new targeted JAK inhibitor therapies, such as ruxolitinib, are now available. The purpose of this article is to review the clinical features of MF, discuss the use and future of JAK inhibitors, reassess when and how to use conventional MF treatments in the context of JAK inhibitors, and provide a perspective on the future of MF treatment.

Nuclear mitochondrial DNA activates replication in Saccharomyces cerevisiae.

PubMed

Chatre, Laurent; Ricchetti, Miria

2011-03-08

The nuclear genome of eukaryotes is colonized by DNA fragments of mitochondrial origin, called NUMTs. These insertions have been associated with a variety of germ-line diseases in humans. The significance of this uptake of potentially dangerous sequences into the nuclear genome is unclear. Here we provide functional evidence that sequences of mitochondrial origin promote nuclear DNA replication in Saccharomyces cerevisiae. We show that NUMTs are rich in key autonomously replicating sequence (ARS) consensus motifs, whose mutation results in the reduction or loss of DNA replication activity. Furthermore, 2D-gel analysis of the mrc1 mutant exposed to hydroxyurea shows that several NUMTs function as late chromosomal origins. We also show that NUMTs located close to or within ARS provide key sequence elements for replication. Thus NUMTs can act as independent origins, when inserted in an appropriate genomic context or affect the efficiency of pre-existing origins. These findings show that migratory mitochondrial DNAs can impact on the replication of the nuclear region they are inserted in.

Checkpoint-dependent RNR induction promotes fork restart after replicative stress.

PubMed

Morafraile, Esther C; Diffley, John F X; Tercero, José Antonio; Segurado, Mónica

2015-01-20

The checkpoint kinase Rad53 is crucial to regulate DNA replication in the presence of replicative stress. Under conditions that interfere with the progression of replication forks, Rad53 prevents Exo1-dependent fork degradation. However, although EXO1 deletion avoids fork degradation in rad53 mutants, it does not suppress their sensitivity to the ribonucleotide reductase (RNR) inhibitor hydroxyurea (HU). In this case, the inability to restart stalled forks is likely to account for the lethality of rad53 mutant cells after replication blocks. Here we show that Rad53 regulates replication restart through the checkpoint-dependent transcriptional response, and more specifically, through RNR induction. Thus, in addition to preventing fork degradation, Rad53 prevents cell death in the presence of HU by regulating RNR-expression and localization. When RNR is induced in the absence of Exo1 and RNR negative regulators, cell viability of rad53 mutants treated with HU is increased and the ability of replication forks to restart after replicative stress is restored.

Elevated serum erythropoietin in a patient with polycythaemia vera presenting with Budd-Chiari syndrome

PubMed Central

Jones, Catherine; Levy, Yair; Tong, Alex W

2014-01-01

Polycythaemia vera (PV) is a clonal disorder of bone marrow stem cells characterised by erythrocytosis. Diagnosis of PV requires exclusion of secondary causes of polycythaemia. It has been held that an elevated erythropoietin (Epo) level strongly indicates secondary erythrocytosis and excludes PV diagnosis, to the extent that the reduced serum Epo level is currently listed as a minor criterion in the WHO classification scheme for PV. However, patients with PV who co-present with Budd-Chiari syndrome have been documented with elevated serum Epo levels. For these patients, identification of the Janus kinase 2 (JAK2) V617F point mutation along with the transient nature of the Epo elevation provides certainty of PV diagnosis, as illustrated by the proband. In this case report, the patient's positive response to cytoreductive therapy (hydroxyurea 500 mg daily) and phlebotomy (750 mL over three phlebotomies) further supports validity of PV diagnosis with elevated Epo. The patient remains on rivaroxaban (Xarelto) for treatment of her portal vein thrombosis. PMID:25452296

Current and future treatment options for polycythemia vera.

PubMed

Griesshammer, Martin; Gisslinger, Heinz; Mesa, Ruben

2015-06-01

Patients with polycythemia vera (PV), a myeloproliferative neoplasm characterized by an elevated red blood cell mass, are at high risk of vascular and thrombotic complications and have reduced quality of life due to a substantial symptom burden that includes pruritus, fatigue, constitutional symptoms, microvascular disturbances, and bleeding. Conventional therapeutic options aim at reducing vascular and thrombotic risk, with low-dose aspirin and phlebotomy as first-line recommendations for patients at low risk of thrombotic events and cytoreductive therapy (usually hydroxyurea or interferon alpha) recommended for high-risk patients. However, long-term effective and well-tolerated treatments are still lacking. The discovery of mutations in Janus kinase 2 (JAK2) as the underlying molecular basis of PV has led to the development of several targeted therapies, including JAK inhibitors, and results from the first phase 3 clinical trial with a JAK inhibitor in PV are now available. Here, we review the current treatment landscape in PV, as well as therapies currently in development.

[Atypical chronic myeloid leukemia presenting with trilineage dysplasia and IgG (lambda) type monoclonal gammopathy].

PubMed

Itoh, K; Kashimura, T; Kobayashi, Y; Yagasaki, F; Sakata, T; Kawai, N; Matsuda, A; Kusumoto, S; Fukuda, M; Ino, H; Murohashi, I; Jinnai, I; Yoshida, S; Bessho, M; Saitoh, M; Hirashima, K

1999-02-01

A 78-year-old man was diagnosed as leukocytosis in February 1994. Physical examination revealed marked hepatosplenomegaly. A peripheral blood examination disclosed 95,090/microliter leukocytes without hiatus leukemicus, 6.5 g/dl Hb, and 15.0 x 10(4)/microliter platelets. The neutrophil alkaline phosphatase score was 27, and serum VB12 was above 1,600pg/ml. IgG was identified as monoclonal immunoglobulin of type lambda. Bone marrow specimens demonstrated marked granulocytic hyperplasia. Neither the Philadelphia chromosome (Ph1) nor BCR gene rearrangement was detected; hence, the diagnosis of Ph1 (-) chronic myeloid leukemia (CML) was made. The patient was treated with hydroxyurea and low-dose VP-16 with no improvement, and died of pneumonia and sepsis in June 1995. This case was considered to be consistent with atypical CML (aCML) according to the FAB classification because monocytosis was not observed. It seems likely and interesting that the coexistent monoclonal gammopathy and aCML might have arisen from common abnormal hematopoietic stem cells.

Iron Reverses Impermeable Chelator Inhibition of DNA Synthesis in CCl39 Cells

NASA Astrophysics Data System (ADS)

Alcain, Francisco J.; Low, Hans; Crane, Frederick L.

1994-08-01

Treatment of Chinese hamster lung fibro-blasts (CCl 39 cells) with the impermeable iron(II) chelator bathophenanthroline disulfonate (BPS) inhibits DNA synthesis when cell growth is initiated with growth factors including epidermal growth factor plus insulin, thrombin, or ceruloplasmin, but not with 10% fetal calf serum. The BPS treatment inhibits transplasma membrane electron transport. The treatment leads to release of iron from the cells as determined by BPS iron(II) complex formation over 90 min. Growth factor stimulation of DNA synthesis and electron transport are restored by addition of di- or trivalent iron to the cells in the form of ferric ammonium citrate, ferrous ammonium sulfate, or diferric transferrin. The effect with BPS differs from the inhibition of growth by hydroxyurea, which acts on the ribonucleotide reductase, or diethylenetriaminepentaacetic acid, which is another impermeable chelating agent, in that these agents inhibit growth in 10% fetal calf serum. The BPS effect is consistent with removal of iron from a site on the cell surface that controls DNA synthesis.

Bilateral Proliferative Retinopathy as the Initial Presentation of Chronic Myeloid Leukemia

PubMed Central

Macedo, Mafalda S. F.; Figueiredo, Ana R. M.; Ferreira, Natália N.; Barbosa, Irene M. A.; Furtado, Maria João F. B. S.; Correia, Nuno F. C. B. A.; Gomes, Miguel P.; Lume, Miguel R. B.; Menéres, Maria João S.; Santos, Marinho M. N.; Meireles S., M. Angelina C.

2013-01-01

The authors report a rare case of a 48-year-old male with chronic myeloid leukemia (CML) who initially presented with a bilateral proliferative retinopathy. The patient complained of recent visual loss and floaters in both eyes (BE). Ophthalmologic evaluation revealed a best corrected visual acuity (BCVA) of 20/50 in the right eye and 20/200 in the left eye (LE). Fundoscopy showed the presence of bilateral peripheral capillary dropout with multiple retinal sea fan neovascularisations, which were confirmed on fluorescein angiography. Full blood count revealed hyperleukocytosis, thrombocytosis, anemia, and hyperuricemia. Bone marrow aspiration and biopsy showed the reciprocal chromosomal translocation t (9;22), diagnostic of CML. The patient was started on hydroxyurea, allopurinol and imatinib mesylate. He received bilateral panretinal laser photocoagulation and a vitrectomy was performed in the LE. The patient has been in complete hematologic, cytogenetic, and major molecular remission while on imatinib and his BCVA is 20/25 in BE. PMID:24339689

The ATR Signaling Pathway Is Disabled during Infection with the Parvovirus Minute Virus of Mice

PubMed Central

Adeyemi, Richard O.

2014-01-01

ABSTRACT The ATR kinase has essential functions in maintenance of genome integrity in response to replication stress. ATR is recruited to RPA-coated single-stranded DNA at DNA damage sites via its interacting partner, ATRIP, which binds to the large subunit of RPA. ATR activation typically leads to activation of the Chk1 kinase among other substrates. We show here that, together with a number of other DNA repair proteins, both ATR and its associated protein, ATRIP, were recruited to viral nuclear replication compartments (autonomous parvovirus-associated replication [APAR] bodies) during replication of the single-stranded parvovirus minute virus of mice (MVM). Chk1, however, was not activated during MVM infection even though viral genomes bearing bound RPA, normally a potent trigger of ATR activation, accumulate in APAR bodies. Failure to activate Chk1 in response to MVM infection was likely due to our observation that Rad9 failed to associate with chromatin at MVM APAR bodies. Additionally, early in infection, prior to the onset of the virus-induced DNA damage response (DDR), stalling of the replication of MVM genomes with hydroxyurea (HU) resulted in Chk1 phosphorylation in a virus dose-dependent manner. However, upon establishment of full viral replication, MVM infection prevented activation of Chk1 in response to HU and various other drug treatments. Finally, ATR phosphorylation became undetectable upon MVM infection, and although virus infection induced RPA32 phosphorylation on serine 33, an ATR-associated phosphorylation site, this phosphorylation event could not be prevented by ATR depletion or inhibition. Together our results suggest that MVM infection disables the ATR signaling pathway. IMPORTANCE Upon infection, the parvovirus MVM activates a cellular DNA damage response that governs virus-induced cell cycle arrest and is required for efficient virus replication. ATM and ATR are major cellular kinases that coordinate the DNA damage response to diverse DNA damage stimuli. Although a significant amount has been discovered about ATM activation during parvovirus infection, involvement of the ATR pathway has been less studied. During MVM infection, Chk1, a major downstream target of ATR, is not detectably phosphorylated even though viral genomes bearing the bound cellular single-strand binding protein RPA, normally a potent trigger of ATR activation, accumulate in viral replication centers. ATR phosphorylation also became undetectable. In addition, upon establishment of full viral replication, MVM infection prevented activation of Chk1 in response to hydroxyurea and various other drug treatments. Our results suggest that MVM infection disables this important cellular signaling pathway. PMID:24965470

The ATR signaling pathway is disabled during infection with the parvovirus minute virus of mice.

PubMed

Adeyemi, Richard O; Pintel, David J

2014-09-01

The ATR kinase has essential functions in maintenance of genome integrity in response to replication stress. ATR is recruited to RPA-coated single-stranded DNA at DNA damage sites via its interacting partner, ATRIP, which binds to the large subunit of RPA. ATR activation typically leads to activation of the Chk1 kinase among other substrates. We show here that, together with a number of other DNA repair proteins, both ATR and its associated protein, ATRIP, were recruited to viral nuclear replication compartments (autonomous parvovirus-associated replication [APAR] bodies) during replication of the single-stranded parvovirus minute virus of mice (MVM). Chk1, however, was not activated during MVM infection even though viral genomes bearing bound RPA, normally a potent trigger of ATR activation, accumulate in APAR bodies. Failure to activate Chk1 in response to MVM infection was likely due to our observation that Rad9 failed to associate with chromatin at MVM APAR bodies. Additionally, early in infection, prior to the onset of the virus-induced DNA damage response (DDR), stalling of the replication of MVM genomes with hydroxyurea (HU) resulted in Chk1 phosphorylation in a virus dose-dependent manner. However, upon establishment of full viral replication, MVM infection prevented activation of Chk1 in response to HU and various other drug treatments. Finally, ATR phosphorylation became undetectable upon MVM infection, and although virus infection induced RPA32 phosphorylation on serine 33, an ATR-associated phosphorylation site, this phosphorylation event could not be prevented by ATR depletion or inhibition. Together our results suggest that MVM infection disables the ATR signaling pathway. Upon infection, the parvovirus MVM activates a cellular DNA damage response that governs virus-induced cell cycle arrest and is required for efficient virus replication. ATM and ATR are major cellular kinases that coordinate the DNA damage response to diverse DNA damage stimuli. Although a significant amount has been discovered about ATM activation during parvovirus infection, involvement of the ATR pathway has been less studied. During MVM infection, Chk1, a major downstream target of ATR, is not detectably phosphorylated even though viral genomes bearing the bound cellular single-strand binding protein RPA, normally a potent trigger of ATR activation, accumulate in viral replication centers. ATR phosphorylation also became undetectable. In addition, upon establishment of full viral replication, MVM infection prevented activation of Chk1 in response to hydroxyurea and various other drug treatments. Our results suggest that MVM infection disables this important cellular signaling pathway. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Evidence for Leydig cell dysfunction in rats with seminiferous tubule damage.

PubMed

Rich, K A; Kerr, J B; de Kretser, D M

1979-02-01

To study the effects of seminiferous tubule damage on Leydig cell function and morphology, rats were treated by fetal irradiation (to induce Sertoli cell-only syndrome, SCO), 3 months administration of hydroxyurea (HU), or chronic feeding of a vitamin A-deficient diet (VAD). Leydig cell function was assessed by the measurement of serum LH and testosterone and the response of serum testosterone to hCG stimulation, while morphology was studied by electron microscopy after perfusion fixation. Serum LH was significantly elevated in each experimental group, while basal serum testosterone was significantly lower only in SCO rats. In all treatment groups, the serum testosterone response to hCG was significantly decreased when measureed as the area under the response curve. Despite a decreased response to hCG, the Leydig cells were larger than normal and showed striking increases in quantities of smooth endoplasmic reticulum, mitochondria and Golgi complex. Leydig cell dysfunction has been demonstrated in animals with varying degrees of seminiferous tubule damage, but paradoxically the cytological features of the Leydig cells were indicative of hypertrophy.

Glutathione S-transferase gene polymorphisms (GSTM1, GSTT1, and GSTP1) in Egyptian pediatric patients with sickle cell disease.

PubMed

Shiba, Hala Fathy; El-Ghamrawy, Mona Kamal; Shaheen, Iman Abd El-Mohsen; Ali, Rasha Abd El-Ghani; Mousa, Somaia Mohammed

2014-01-01

Sickle cell disease (SCD) complications are associated with oxidative stress. Glutathione S-transferases (GSTs) are a group of enzymes that protect against oxidative stress. The aims of this study was to evaluate the prevalence of GSTM1, GSTT1, and GSTP1 gene polymorphisms among homozygous sickle cell anemia patients and to investigate the possible association between the presence of these polymorphisms and SCD severity and complications. Genotyping the polymorphisms in GSTT1 and GSTM1 genes was performed using the multiplex polymerase chain reaction (PCR) method. The GSTP1 ILe105Val polymorphism was determined using PCR-restriction fragment length polymorphism. GSTM1 null genotype was significantly associated with increased risk of severe vaso-occlusive crises (VOC) (odds ratio  =  1.52, 95% confidence interval  =  0.42-5.56, P  =  0.005). We found no significant association between GST genotypes and frequency of sickle cell-related pain, transfusion frequency, disease severity, or hydroxyurea treatment. GSTM1 gene polymorphism may be associated with risk of severe VOC among Egyptian SCD patients.

Activity of single-agent decitabine in atypical chronic myeloid leukemia.

PubMed

Hausmann, Heidi; Bhatt, Vijaya R; Yuan, Ji; Maness, Lori J; Ganti, Apar K

2016-12-01

Atypical chronic myeloid leukemia is a rare entity that presents diagnostic and therapeutic challenges. Traditionally utilized therapeutic agents such as hydroxyurea or interferon result in a median survival of approximately two years, thus warranting identification of better options. We report a 49-year-old Caucasian female, who presented with extreme leukocytosis (white blood cells of 148,300/µL) with left shift, severe anemia, and thrombocytopenia. Following a diagnosis of atypical chronic myeloid leukemia, she was started on intravenous decitabine. She subsequently developed paraneoplastic vasculitis of large arteries, which responded to high-dose glucocorticoid. Decitabine therapy resulted in an excellent hematologic response, transfusion independence, and successful transition to an allogeneic peripheral stem cell transplantation. However, the patient subsequently succumbed to the complications of acute graft-versus-host-disease. This case illustrates an association between atypical chronic myeloid leukemia and steroid-responsive paraneoplastic vasculitis and highlights the single-agent disease activity of decitabine in atypical chronic myeloid leukemia, which may be utilized as a bridging therapy to allogeneic stem cell transplantation. © The Author(s) 2015.

Inflammation in sickle cell disease.

PubMed

Conran, Nicola; Belcher, John D

2018-01-01

The primary β-globin gene mutation that causes sickle cell disease (SCD) has significant pathophysiological consequences that result in hemolytic events and the induction of the inflammatory processes that ultimately lead to vaso-occlusion. In addition to their role in the initiation of the acute painful vaso-occlusive episodes that are characteristic of SCD, inflammatory processes are also key components of many of the complications of the disease including autosplenectomy, acute chest syndrome, pulmonary hypertension, leg ulcers, nephropathy and stroke. We, herein, discuss the events that trigger inflammation in the disease, as well as the mechanisms, inflammatory molecules and cells that propagate these inflammatory processes. Given the central role that inflammation plays in SCD pathophysiology, many of the therapeutic approaches currently under pre-clinical and clinical development for the treatment of SCD endeavor to counter aspects or specific molecules of these inflammatory processes and it is possible that, in the future, we will see anti-inflammatory drugs being used either together with, or in place of, hydroxyurea in those SCD patients for whom hematopoietic stem cell transplants and evolving gene therapies are not a viable option.

Human CST Facilitates Genome-wide RAD51 Recruitment to GC-Rich Repetitive Sequences in Response to Replication Stress.

PubMed

Chastain, Megan; Zhou, Qing; Shiva, Olga; Fadri-Moskwik, Maria; Whitmore, Leanne; Jia, Pingping; Dai, Xueyu; Huang, Chenhui; Ye, Ping; Chai, Weihang

2016-08-02

The telomeric CTC1/STN1/TEN1 (CST) complex has been implicated in promoting replication recovery under replication stress at genomic regions, yet its precise role is unclear. Here, we report that STN1 is enriched at GC-rich repetitive sequences genome-wide in response to hydroxyurea (HU)-induced replication stress. STN1 deficiency exacerbates the fragility of these sequences under replication stress, resulting in chromosome fragmentation. We find that upon fork stalling, CST proteins form distinct nuclear foci that colocalize with RAD51. Furthermore, replication stress induces physical association of CST with RAD51 in an ATR-dependent manner. Strikingly, CST deficiency diminishes HU-induced RAD51 foci formation and reduces RAD51 recruitment to telomeres and non-telomeric GC-rich fragile sequences. Collectively, our findings establish that CST promotes RAD51 recruitment to GC-rich repetitive sequences in response to replication stress to facilitate replication restart, thereby providing insights into the mechanism underlying genome stability maintenance. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

The nuclear DEK interactome supports multi-functionality.

PubMed

Smith, Eric A; Krumpelbeck, Eric F; Jegga, Anil G; Prell, Malte; Matrka, Marie M; Kappes, Ferdinand; Greis, Kenneth D; Ali, Abdullah M; Meetei, Amom R; Wells, Susanne I

2018-01-01

DEK is an oncoprotein that is overexpressed in many forms of cancer and participates in numerous cellular pathways. Of these different pathways, relevant interacting partners and functions of DEK are well described in regard to the regulation of chromatin structure, epigenetic marks, and transcription. Most of this understanding was derived by investigating DNA-binding and chromatin processing capabilities of the oncoprotein. To facilitate the generation of mechanism-driven hypotheses regarding DEK activities in underexplored areas, we have developed the first DEK interactome model using tandem-affinity purification and mass spectrometry. With this approach, we identify IMPDH2, DDX21, and RPL7a as novel DEK binding partners, hinting at new roles for the oncogene in de novo nucleotide biosynthesis and ribosome formation. Additionally, a hydroxyurea-specific interaction with replication protein A (RPA) was observed, suggesting that a DEK-RPA complex may form in response to DNA replication fork stalling. Taken together, these findings highlight diverse activities for DEK across cellular pathways and support a model wherein this molecule performs a plethora of functions. © 2017 Wiley Periodicals, Inc.

Arrest of cell cycle by inhibition of ribonucleotide reductase induces accumulation of NAD+ by Mn2+-supplemented growth of Corynebacterium ammoniagenes.

PubMed

Abbouni, Bouziane; Elhariry, Hesham M; Auling, Georg

2003-01-01

Cell division of the wild type strain Corynebacterium (formerly Brevibacterium) ammoniagenes ATCC 6872 which requires 1 microM Mn2+ for balanced growth was inhibited by addition of 20 mM hydroxyurea (HU) or 10 mM p-methoxyphenol (MP) to a Mn2+-supplemented fermentation medium at an appropriate time. Scanning electron microscopy (SEM) showed a restricted elongation characteristic of arrest of the cell cycle in coryneform bacteria. The cultures treated with HU or MP had, respectively, a fourfold or sixfold enhanced accumulation of NAD+ by a salvage biosynthetic pathway. An assay of nucleotide-permeable cells for ribonucleotide reductase activity using [3H-CDP] as substrate revealed a pre-early and complete decline of DNA precursor biosynthesis not found in the untreated control. Overproduction of NAD+ is an alternative to the conventional fermentation process using Mn2+ deficiency. A simple model is presented to discuss the metabolic regulation of the new process based on the presence of a manganese ribonucleotide reductase (Mn-RNR) in the producing strain.

Common Chemical Inductors of Replication Stress:  Focus on Cell-Based Studies.

PubMed

Vesela, Eva; Chroma, Katarina; Turi, Zsofia; Mistrik, Martin

2017-02-21

DNA replication is a highly demanding process regarding the energy and material supply and must be precisely regulated, involving multiple cellular feedbacks. The slowing down or stalling of DNA synthesis and/or replication forks is referred to as replication stress (RS). Owing to the complexity and requirements of replication, a plethora of factors may interfere and challenge the genome stability, cell survival or affect the whole organism. This review outlines chemical compounds that are known inducers of RS and commonly used in laboratory research. These compounds act on replication by direct interaction with DNA causing DNA crosslinks and bulky lesions (cisplatin), chemical interference with the metabolism of deoxyribonucleotide triphosphates (hydroxyurea), direct inhibition of the activity of replicative DNA polymerases (aphidicolin) and interference with enzymes dealing with topological DNA stress (camptothecin, etoposide). As a variety of mechanisms can induce RS, the responses of mammalian cells also vary. Here, we review the activity and mechanism of action of these compounds based on recent knowledge, accompanied by examples of induced phenotypes, cellular readouts and commonly used doses.

Common Chemical Inductors of Replication Stress: Focus on Cell-Based Studies

PubMed Central

Vesela, Eva; Chroma, Katarina; Turi, Zsofia; Mistrik, Martin

2017-01-01

DNA replication is a highly demanding process regarding the energy and material supply and must be precisely regulated, involving multiple cellular feedbacks. The slowing down or stalling of DNA synthesis and/or replication forks is referred to as replication stress (RS). Owing to the complexity and requirements of replication, a plethora of factors may interfere and challenge the genome stability, cell survival or affect the whole organism. This review outlines chemical compounds that are known inducers of RS and commonly used in laboratory research. These compounds act on replication by direct interaction with DNA causing DNA crosslinks and bulky lesions (cisplatin), chemical interference with the metabolism of deoxyribonucleotide triphosphates (hydroxyurea), direct inhibition of the activity of replicative DNA polymerases (aphidicolin) and interference with enzymes dealing with topological DNA stress (camptothecin, etoposide). As a variety of mechanisms can induce RS, the responses of mammalian cells also vary. Here, we review the activity and mechanism of action of these compounds based on recent knowledge, accompanied by examples of induced phenotypes, cellular readouts and commonly used doses. PMID:28230817

Pathological basis of symptoms and crises in sickle cell disorder: implications for counseling and psychotherapy

PubMed Central

Ilesanmi, Oluwatoyin Olatundun

2010-01-01

Sickle Cell Disorder (SCD) is a congenital hemoglobinopathy. There is little in literature regarding the psychological variables affecting individuals living with SCD and all of the significant people around them. There are also limited numbers of trained clinical psychologists and genetic counselors to cater for the psychotherapeutic needs of individuals living with SCD. Even among those who have been trained, only a few might have fully grasped the complexities of the disease pathology. Early understanding of its pathological nature, sources, types, complications, pathophysiological basis, and clinical severity of symptoms among clinical psychologists, genetic counselors and psychotherapists, as well as general medical practitioners, could guide them in providing holistic care for dealing with and reducing pain among individuals living with SCD. It could allow risk-based counseling for families and individuals. It could also justify the early use of disease-modifying or curative interventions, such as hydroxyurea (HU), chronic transfusions (CTs), or stem-cell transplantation (SCT) by general medical practitioners. Hence, the need for this paper on the pathophysiology of SCD. PMID:22184515

Cell-cycle synchronisation of bloodstream forms of Trypanosoma brucei using Vybrant DyeCycle Violet-based sorting.

PubMed

Kabani, Sarah; Waterfall, Martin; Matthews, Keith R

2010-01-01

Studies on the cell-cycle of Trypanosoma brucei have revealed several unusual characteristics that differ from the model eukaryotic organisms. However, the inability to isolate homogenous populations of parasites in distinct cell-cycle stages has limited the analysis of trypanosome cell division and complicated the understanding of mutant phenotypes with possible impact on cell-cycle related events. Although hydroxyurea-induced cell-cycle arrest in procyclic and bloodstream forms has been applied recently with success, such block-release protocols can complicate the analysis of cell-cycle regulated events and have the potential to disrupt important cell-cycle checkpoints. An alternative approach based on flow cytometry of parasites stained with Vybrant DyeCycle Orange circumvents this problem, but is restricted to procyclic form parasites. Here, we apply Vybrant Dyecycle Violet staining coupled with flow cytometry to effectively select different cell-cycle stages of bloodstream form trypanosomes. Moreover, the sorted parasites remain viable, although synchrony is rapidly lost. This method enables cell-cycle enrichment of populations of trypanosomes in their mammal infective stage, particularly at the G1 phase.

Cell-cycle synchronisation of bloodstream forms of Trypanosoma brucei using Vybrant DyeCycle Violet-based sorting

PubMed Central

Kabani, Sarah; Waterfall, Martin; Matthews, Keith R.

2010-01-01

Studies on the cell-cycle of Trypanosoma brucei have revealed several unusual characteristics that differ from the model eukaryotic organisms. However, the inability to isolate homogenous populations of parasites in distinct cell-cycle stages has limited the analysis of trypanosome cell division and complicated the understanding of mutant phenotypes with possible impact on cell-cycle related events. Although hydroxyurea-induced cell-cycle arrest in procyclic and bloodstream forms has been applied recently with success, such block-release protocols can complicate the analysis of cell-cycle regulated events and have the potential to disrupt important cell-cycle checkpoints. An alternative approach based on flow cytometry of parasites stained with Vybrant DyeCycle Orange circumvents this problem, but is restricted to procyclic form parasites. Here, we apply Vybrant Dyecycle Violet staining coupled with flow cytometry to effectively select different cell-cycle stages of bloodstream form trypanosomes. Moreover, the sorted parasites remain viable, although synchrony is rapidly lost. This method enables cell-cycle enrichment of populations of trypanosomes in their mammal infective stage, particularly at the G1 phase. PMID:19729042

Investigation of carboxylation of carbon nanotube in the adsorption of anti-cancer drug: A theoretical approach

NASA Astrophysics Data System (ADS)

Hesabi, Maryam; Behjatmanesh-Ardakani, Reza

2018-01-01

Nowadays, an important process applied in the design of novel composite materials and drug delivery fields is the carboxylation of carbon nanotubes. In this work, we study the interaction of the anti-cancer drug hydroxyurea with carboxyl-functionalized zigzag carbon nanotubes (CNTs) by employing the method of the density functional theory (DFT) at B3LYP and CAM-B3LYP levels in gas and solvent phases. The results show that all complexes are energetically favorable, especially in the aqueous phase. The enthalpy energy values are negative in all cases, which indicate their exothermic adsorption nature. The presence of sbnd COOH groups would create enough free space on the nanotube surface for the adsorption between interacting atoms. Thus, these can increase the activity of CNTs. Data indicates that adsorption is dependent on the carboxyl sites of the nanotube as well as on the sites of the drug. Furthermore, the hydrogen-bonding interactions between drug and sbnd COOH-CNTs play an important role for the different kinds of adsorption observed.

Knockdown of RMI1 impairs DNA repair under DNA replication stress.

PubMed

Xu, Chang; Fang, Lianying; Kong, Yangyang; Xiao, Changyan; Yang, Mengmeng; Du, Li-Qing; Liu, Qiang

2017-12-09

RMI1 (RecQ-mediated genome instability protein 1) forms a conserved BTR complex with BLM, Topo IIIα, and RMI2, and its absence causes genome instability. It has been revealed that RMI1 localizes to nuclear foci with BLM and Topo IIIα in response to replication stress, and that RMI1 functions downstream of BLM in promoting replication elongation. However, the precise functions of RMI1 during replication stress are not completely understood. Here we report that RMI1 knockdown cells are hypersensitive to hydroxyurea (HU). Using comet assay, we show that RMI1 knockdown cells exhibit accumulation of broken DNAs after being released from HU treatment. Moreover, we demonstrate that RMI1 facilitates the recovery from activated checkpoint and resuming the cell cycle after replicative stress. Surprisingly, loss of RMI1 results in a failure of RAD51 loading onto DNA damage sites. These findings reveal the importance of RMI1 in response to replication stress, which could explain the molecular basis for its function in maintaining genome integrity. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Replication stress-induced chromosome breakage is correlated with replication fork progression and is preceded by single-stranded DNA formation.

PubMed

Feng, Wenyi; Di Rienzi, Sara C; Raghuraman, M K; Brewer, Bonita J

2011-10-01

Chromosome breakage as a result of replication stress has been hypothesized to be the direct consequence of defective replication fork progression, or "collapsed" replication forks. However, direct and genome-wide evidence that collapsed replication forks give rise to chromosome breakage is still lacking. Previously we showed that a yeast replication checkpoint mutant mec1-1, after transient exposure to replication impediment imposed by hydroxyurea (HU), failed to complete DNA replication, accumulated single-stranded DNA (ssDNA) at the replication forks, and fragmented its chromosomes. In this study, by following replication fork progression genome-wide via ssDNA detection and by direct mapping of chromosome breakage after HU exposure, we have tested the hypothesis that the chromosome breakage in mec1 cells occurs at collapsed replication forks. We demonstrate that sites of chromosome breakage indeed correlate with replication fork locations. Moreover, ssDNA can be detected prior to chromosome breakage, suggesting that ssDNA accumulation is the common precursor to double strand breaks at collapsed replication forks.

The Yeast Copper Response Is Regulated by DNA Damage

PubMed Central

Dong, Kangzhen; Addinall, Stephen G.; Lydall, David

2013-01-01

Copper is an essential but potentially toxic redox-active metal, so the levels and distribution of this metal are carefully regulated to ensure that it binds to the correct proteins. Previous studies of copper-dependent transcription in the yeast Saccharomyces cerevisiae have focused on the response of genes to changes in the exogenous levels of copper. We now report that yeast copper genes are regulated in response to the DNA-damaging agents methyl methanesulfonate (MMS) and hydroxyurea by a mechanism(s) that requires the copper-responsive transcription factors Mac1 and AceI, copper superoxide dismutase (Sod1) activity, and the Rad53 checkpoint kinase. Furthermore, in copper-starved yeast, the response of the Rad53 pathway to MMS is compromised due to a loss of Sod1 activity, consistent with the model that yeast imports copper to ensure Sod1 activity and Rad53 signaling. Crucially, the Mac1 transcription factor undergoes changes in its redox state in response to changing levels of copper or MMS. This study has therefore identified a novel regulatory relationship between cellular redox, copper homeostasis, and the DNA damage response in yeast. PMID:23959798

FANCJ/BRIP1 recruitment and regulation of FANCD2 in DNA damage responses

PubMed Central

Zhang, Fan; Fan, Qiang; Ren, Keqin; Auerbach, Arleen D.; Andreassen, Paul R.

2016-01-01

FANCJ/BRIP1 encodes a helicase that has been implicated in the maintenance of genomic stability. Here, to better understand FANCJ function in DNA damage responses, we have examined the regulation of its cellular localization. FANCJ nuclear foci assemble spontaneously during S phase and are induced by various stresses. FANCJ foci colocalize with the replication fork following treatment with hydroxyurea, but not spontaneously. Using FANCJ mutants, we find that FANCJ helicase activity and the capacity to bind BRCA1 are both involved in FANCJ recruitment. Given similarities to the recruitment of another Fanconi anemia protein, FANCD2, we tested for colocalization of FANCJ and FANCD2. Importantly, these proteins show substantial colocalization, and FANCJ promotes the assembly of FANCD2 nuclear foci. This process is linked to the proper localization of FANCJ itself since both FANCJ and FANCD2 nuclear foci are compromised by FANCJ mutants that abrogate its helicase activity or interaction with BRCA1. Our results suggest that FANCJ is recruited in response to replication stress and that FANCJ/BRIP1 may serve to link FANCD2 to BRCA1. PMID:20676667

Interaction between the helicases genetically linked to Fanconi anemia group J and Bloom's syndrome

PubMed Central

Suhasini, Avvaru N; Rawtani, Nina A; Wu, Yuliang; Sommers, Joshua A; Sharma, Sudha; Mosedale, Georgina; North, Phillip S; Cantor, Sharon B; Hickson, Ian D; Brosh, Robert M

2011-01-01

Bloom's syndrome (BS) and Fanconi anemia (FA) are autosomal recessive disorders characterized by cancer and chromosomal instability. BS and FA group J arise from mutations in the BLM and FANCJ genes, respectively, which encode DNA helicases. In this work, FANCJ and BLM were found to interact physically and functionally in human cells and co-localize to nuclear foci in response to replication stress. The cellular level of BLM is strongly dependent upon FANCJ, and BLM is degraded by a proteasome-mediated pathway when FANCJ is depleted. FANCJ-deficient cells display increased sister chromatid exchange and sensitivity to replication stress. Expression of a FANCJ C-terminal fragment that interacts with BLM exerted a dominant negative effect on hydroxyurea resistance by interfering with the FANCJ–BLM interaction. FANCJ and BLM synergistically unwound a DNA duplex substrate with sugar phosphate backbone discontinuity, but not an ‘undamaged' duplex. Collectively, the results suggest that FANCJ catalytic activity and its effect on BLM protein stability contribute to preservation of genomic stability and a normal response to replication stress. PMID:21240188

[French guidelines for the management of adult sickle cell disease: 2015 update].

PubMed

Habibi, A; Arlet, J-B; Stankovic, K; Gellen-Dautremer, J; Ribeil, J-A; Bartolucci, P; Lionnet, F

2015-05-11

Sickle cell disease is a systemic genetic disorder, causing many functional and tissular modifications. As the prevalence of patients with sickle cell disease increases gradually in France, every physician can be potentially involved in the care of these patients. Complications of sickle cell disease can be acute and chronic. Pain is the main symptom and should be treated quickly and aggressively. In order to reduce the fatality rate associated with acute chest syndrome, it must be detected and treated early. Chronic complications are one of the main concerns in adults and should be identified as early as possible in order to prevent end organ damage. Many organs can be involved, including bones, kidneys, eyes, lungs, etc. The indications for a specific treatment (blood transfusion or hydroxyurea) should be regularly discussed. Coordinated health care should be carefully organized to allow a regular follow-up near the living place and access to specialized departments. We present in this article the French guidelines for the sickle cell disease management in adulthood. Copyright © 2015 Elsevier Inc. All rights reserved.

Replication-mediated disassociation of replication protein A-XPA complex upon DNA damage: implications for RPA handing off.

PubMed

Jiang, Gaofeng; Zou, Yue; Wu, Xiaoming

2012-08-01

RPA (replication protein A), the eukaryotic ssDNA (single-stranded DNA)-binding protein, participates in most cellular processes in response to genotoxic insults, such as NER (nucleotide excision repair), DNA, DSB (double-strand break) repair and activation of cell cycle checkpoint signalling. RPA interacts with XPA (xeroderma pigmentosum A) and functions in early stage of NER. We have shown that in cells the RPA-XPA complex disassociated upon exposure of cells to high dose of UV irradiation. The dissociation required replication stress and was partially attributed to tRPA hyperphosphorylation. Treatment of cells with CPT (camptothecin) and HU (hydroxyurea), which cause DSB DNA damage and replication fork collapse respectively and also leads to the disruption of RPA-XPA complex. Purified RPA and XPA were unable to form complex in vitro in the presence of ssDNA. We propose that the competition-based RPA switch among different DNA metabolic pathways regulates the dissociation of RPA with XPA in cells after DNA damage. The biological significances of RPA-XPA complex disruption in relation with checkpoint activation, DSB repair and RPA hyperphosphorylation are discussed.

Polycythemia Vera: An Appraisal of the Biology and Management 10 Years After the Discovery of JAK2 V617F

PubMed Central

Stein, Brady L.; Oh, Stephen T.; Berenzon, Dmitriy; Hobbs, Gabriela S.; Kremyanskaya, Marina; Rampal, Raajit K.; Abboud, Camille N.; Adler, Kenneth; Heaney, Mark L.; Jabbour, Elias J.; Komrokji, Rami S.; Moliterno, Alison R.; Ritchie, Ellen K.; Rice, Lawrence; Mascarenhas, John; Hoffman, Ronald

2015-01-01

Polycythemia vera (PV) is a chronic myeloproliferative neoplasm that is associated with a substantial symptom burden, thrombohemorrhagic complications, and impaired survival. A decade after the seminal discovery of an activating mutation in the tyrosine kinase JAK2 in nearly all patients with PV, new treatment options are finally beginning to emerge, necessitating a critical reappraisal of the underlying pathogenesis and therapeutic modalities available for PV. Herein, we comprehensively review clinical aspects of PV including diagnostic considerations, natural history, and risk factors for thrombosis. We summarize recent studies delineating the genetic basis of PV, including their implications for evolution to myelofibrosis and secondary acute myeloid leukemia. We assess the quality of evidence to support the use of currently available therapies, including aspirin, phlebotomy, hydroxyurea, and interferon. We analyze recent studies evaluating the safety and efficacy of JAK inhibitors, such as ruxolitinib, and evaluate their role in the context of other available therapies for PV. This review provides a framework for practicing hematologists and oncologists to make rational treatment decisions for patients with PV. PMID:26324368

NORF5/HUG1 is a component of the MEC1-mediated checkpoint response to DNA damage and replication arrest in Saccharomyces cerevisiae.

PubMed

Basrai, M A; Velculescu, V E; Kinzler, K W; Hieter, P

1999-10-01

Analysis of global gene expression in Saccharomyces cerevisiae by the serial analysis of gene expression technique has permitted the identification of at least 302 previously unidentified transcripts from nonannotated open reading frames (NORFs). Transcription of one of these, NORF5/HUG1 (hydroxyurea and UV and gamma radiation induced), is induced by DNA damage, and this induction requires MEC1, a homolog of the ataxia telangiectasia mutated (ATM) gene. DNA damage-specific induction of HUG1, which is independent of the cell cycle stage, is due to the alleviation of repression by the Crt1p-Ssn6p-Tup1p complex. Overexpression of HUG1 is lethal in combination with a mec1 mutation in the presence of DNA damage or replication arrest, whereas a deletion of HUG1 rescues the lethality due to a mec1 null allele. HUG1 is the first example of a NORF with important biological functional properties and defines a novel component of the MEC1 checkpoint pathway.

Population pharmacokinetics and pharmacodynamics of hydroxyurea in sickle cell anemia patients, a basis for optimizing the dosing regimen

PubMed Central

2011-01-01

Background Hydroxyurea (HU) is the first approved pharmacological treatment of sickle cell anemia (SCA). The objectives of this study were to develop population pharmacokinetic(PK)-pharmacodynamic(PD) models for HU in order to characterize the exposure-efficacy relationships and their variability, compare two dosing regimens by simulations and develop some recommendations for monitoring the treatment. Methods The models were built using population modelling software NONMEM VII based on data from two clinical studies of SCA adult patients receiving 500-2000 mg of HU once daily. Fetal hemoglobin percentage (HbF%) and mean corpuscular volume (MCV) were used as biomarkers for response. A sequential modelling approach was applied. Models were evaluated using simulation-based techniques. Comparisons of two dosing regimens were performed by simulating 10000 patients in each arm during 12 months. Results The PK profiles were described by a bicompartmental model. The median (and interindividual coefficient of variation (CV)) of clearance was 11.6 L/h (30%), the central volume was 45.3 L (35%). PK steady-state was reached in about 35 days. For a given dosing regimen, HU exposure varied approximately fivefold among patients. The dynamics of HbF% and MCV were described by turnover models with inhibition of elimination of response. In the studied range of drug exposures, the effect of HU on HbF% was at its maximum (median Imax was 0.57, CV was 27%); the effect on MCV was close to its maximum, with median value of 0.14 and CV of 49%. Simulations showed that 95% of the steady-state levels of HbF% and MCV need 26 months and 3 months to be reached, respectively. The CV of the steady-state value of HbF% was about 7 times larger than that of MCV. Simulations with two different dosing regimens showed that continuous dosing led to a stronger HbF% increase in some patients. Conclusions The high variability of response to HU was related in part to pharmacokinetics and to pharmacodynamics. The steady-state value of MCV at month 3 is not predictive of the HbF% value at month 26. Hence, HbF% level may be a better biomarker for monitoring HU treatment. Continuous dosing might be more advantageous in terms of HbF% for patients who have a strong response to HU. Trial Registration The clinical studies whose data are analysed and reported in this work were not required to be registered in France at their time. Both studies were approved by local ethics committees (of Mondor Hospital and of Kremlin-Bicetre Hospital) and written informed consent was obtained from each patient. PMID:21619673

Human Neural Stem Cell Aging Is Counteracted by α-Glycerylphosphorylethanolamine.

PubMed

Daniele, Simona; Da Pozzo, Eleonora; Iofrida, Caterina; Martini, Claudia

2016-07-20

Neural stem cells (NSCs) represent a subpopulation of cells, located in specific regions of the adult mammalian brain, with the ability of self-renewing and generating neurons and glia. In aged NSCs, modifications in the amount and composition of membrane proteins/lipids, which lead to a reduction in membrane fluidity and cholinergic activities, have been reported. In this respect, molecules that are effective at normalizing the membrane composition and cholinergic signaling could counteract stem cell aging. α-Glycerylphosphorylethanolamine (GPE), a nootropic drug, plays a role in phospholipid biosynthesis and acetylcholine release. Herein, GPE was assayed on human NSC cultures and on hydroxyurea-aged cells. Using cell counting, colorimetric, and fluorimetric analyses, immunoenzymatic assays, and real time PCR experiments, NSC culture proliferation, senescence, reactive oxygen species, and ADP/ATP levels were assessed. Aged NSCs exhibited cellular senescence, decreased proliferation, and an impairment in mitochondrial metabolism. These changes included a substantial induction in the nuclear factor NF-κB, a key inflammatory mediator. GPE cell treatment significantly protected the redox state and functional integrity of mitochondria, and counteracted senescence and NF-κB activation. In conclusion, our data show the beneficial properties of GPE in this model of stem cell aging.

Thiols, recA induction and radiosensitivity in Escherichia coli.

PubMed

Naslund, M; Anderstam, B; Granath, F; Ehrenberg, L

1996-01-01

Induction by gamma-radiation, UV radiation or hydroxyurea of RecA gene product synthesis in Escherichia coli, monitored as beta-D-galactosidase in recA-lacZ fusion strains, was shown to be inhibited if 2-mercaptoethylamine (MEA) was added before treatment with the inducing agents. If cysteine (Cys) at low concentrations was added at the same time as MEA it counteracted the action of MEA. The effect of MEA may be described as a competitive inhibition of an inducing or conducting effect of Cys. In E. coli GE499 (uvrA+), complete inhibition by 30-mmol dm-3 MEA of recA induction was associated with about five times higher radio-resistence. Both of these effects of MEA were completely reversed by 0.3-mmol dm-3 Cys. As shown in parallel experiments with E. coli GE500 (uvrA-), these effects of MEA and Cys were shown to be independent of excision-repair proficiency. Treatment of bacteria with MEA and/or Cys was shown not to lead to increased intracellular concentrations of these thiols. Instead, treatment with them appeared to provoke conspicuous increases in glutathione levels, which are, however, probably not directly involved in the studied action of MEA and Cys.

A novel transcription factor gene FHS1 is involved in the DNA damage response in Fusarium graminearum

PubMed Central

Son, Hokyoung; Fu, Minmin; Lee, Yoonji; Lim, Jae Yun; Min, Kyunghun; Kim, Jin-Cheol; Choi, Gyung Ja; Lee, Yin-Won

2016-01-01

Cell cycle regulation and the maintenance of genome integrity are crucial for the development and virulence of the pathogenic plant fungus Fusarium graminearum. To identify transcription factors (TFs) related to these processes, four DNA-damaging agents were applied to screen a F. graminearum TF mutant library. Sixteen TFs were identified to be likely involved in DNA damage responses. Fhs1 is a fungal specific Zn(II)2Cys6 TF that localises exclusively to nuclei. fhs1 deletion mutants were hypersensitive to hydroxyurea and defective in mitotic cell division. Moreover, deletion of FHS1 resulted in defects in perithecia production and virulence and led to the accumulation of DNA damage. Our genetic evidence demonstrated that the FHS1-associated signalling pathway for DNA damage response is independent of the ATM or ATR pathways. This study identified sixteen genes involved in the DNA damage response and is the first to characterise the novel transcription factor gene FHS1, which is involved in the DNA damage response. The results provide new insights into mechanisms underlying DNA damage responses in fungi, including F. graminearum. PMID:26888604

The mammalian INO80 chromatin remodeling complex is required for replication stress recovery

PubMed Central

Vassileva, Ivelina; Yanakieva, Iskra; Peycheva, Michaela; Gospodinov, Anastas; Anachkova, Boyka

2014-01-01

A number of studies have implicated the yeast INO80 chromatin remodeling complex in DNA replication, but the function of the human INO80 complex during S phase remains poorly understood. Here, we have systematically investigated the involvement of the catalytic subunit of the human INO80 complex during unchallenged replication and under replication stress by following the effects of its depletion on cell survival, S-phase checkpoint activation, the fate of individual replication forks, and the consequences of fork collapse. We report that INO80 was specifically needed for efficient replication elongation, while it was not required for initiation of replication. In the absence of the Ino80 protein, cells became hypersensitive to hydroxyurea and displayed hyperactive ATR-Chk1 signaling. Using bulk and fiber labeling of DNA, we found that cells deficient for Ino80 and Arp8 had impaired replication restart after treatment with replication inhibitors and accumulated double-strand breaks as evidenced by the formation of γ-H2AX and Rad51 foci. These data indicate that under conditions of replication stress mammalian INO80 protects stalled forks from collapsing and allows their subsequent restart. PMID:25016522

Re-emergence of interferon-α in the treatment of chronic myeloid leukemia

PubMed Central

Talpaz, M; Hehlmann, R; Quintás-Cardama, A; Mercer, J; Cortes, J

2013-01-01

Treatment for chronic myeloid leukemia (CML) has evolved from chemotherapy (busulfan, hydroxyurea) to interferon-α (IFNα), and finally to tyrosine kinase inhibitors such as imatinib. Although imatinib has profoundly improved outcomes for patients with CML, it has limitations. Most significantly, imatinib cannot eradicate CML primitive progenitors, which likely accounts for the high relapse rate when imatinib is discontinued. IFNα, unlike imatinib, preferentially targets CML stem cells. Early studies with IFNα in CML demonstrated its ability to induce cytogenetic remission. Moreover, a small percentage of patients treated with IFNα were able to sustain durable remissions after discontinuing therapy and were probably cured. The mechanisms by which IFNα exerts its antitumor activity in CML are not well understood; however, activation of leukemia-specific immunity may have a role. Some clinical studies have demonstrated that the combination of imatinib and IFNα is superior to either therapy alone, perhaps because of their different mechanisms of action. Nonetheless, the side effects of IFNα often impede its administration, especially in combination therapy. Here, we review the role of IFNα in CML treatment and the recent developments that have renewed interest in this once standard therapy for patients with CML. PMID:23238589

Management of Sickle Cell Disease: A Review for Physician Education in Nigeria (Sub-Saharan Africa)

PubMed Central

Adewoyin, Ademola Samson

2015-01-01

Sickle cell disease (SCD) predominates in sub-Saharan Africa, East Mediterranean areas, Middle East, and India. Nigeria, being the most populous black nation in the world, bears its greatest burden in sub-Saharan Africa. The last few decades have witnessed remarkable scientific progress in the understanding of the complex pathophysiology of the disease. Improved clinical insights have heralded development and establishment of disease modifying interventions such as chronic blood transfusions, hydroxyurea therapy, and haemopoietic stem cell transplantation. Coupled with parallel improvements in general supportive, symptomatic, and preventive measures, current evidence reveals remarkable appreciation in quality of life among affected individuals in developed nations. Currently, in Nigeria and other West African states, treatment and control of SCD are largely suboptimal. Improved knowledge regarding SCD phenotypes and its comprehensive care among Nigerian physicians will enhance quality of care for affected persons. This paper therefore provides a review on the aetiopathogenesis, clinical manifestations, and management of SCD in Nigeria, with a focus on its local patterns and peculiarities. Established treatment guidelines as appropriate in the Nigerian setting are proffered, as well as recommendations for improving care of affected persons. PMID:25667774

Arginine-rich cross-linking peptides with different SV40 nuclear localization signal content as vectors for intranuclear DNA delivery.

PubMed

Bogacheva, Mariia; Egorova, Anna; Slita, Anna; Maretina, Marianna; Baranov, Vladislav; Kiselev, Anton

2017-11-01

The major barriers for intracellular DNA transportation by cationic polymers are their toxicity, poor endosomal escape and inefficient nuclear uptake. Therefore, we designed novel modular peptide-based carriers modified with SV40 nuclear localization signal (NLS). Core peptide consists of arginine, histidine and cysteine residues for DNA condensation, endosomal escape promotion and interpeptide cross-linking, respectively. We investigated three polyplexes with different NLS content (10 mol%, 50 mol% and 90 mol% of SV40 NLS) as vectors for intranuclear DNA delivery. All carriers tested were able to condense DNA, to protect it from DNAase I and were not toxic to the cells. We observed that cell cycle arrest by hydroxyurea did not affect transfection efficacy of NLS-modified carriers which we confirmed using quantitative confocal microscopy analysis. Overall, peptide carrier modified with 90 mol% of SV40 NLS provided efficient transfection and nuclear uptake in non-dividing cells. Thus, incorporation of NLS into arginine-rich cross-linking peptides is an adequate approach to the development of efficient intranuclear gene delivery vehicles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Overexpression of high molecular weight FGF-2 forms inhibits glioma growth by acting on cell-cycle progression and protein translation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lemiere, Sylvie; University Bordeaux1, Talence, F-33405; Azar, Rania

2008-12-10

In order to clarify the role of HMW FGF-2 in glioma development and angiogenesis, we over-expressed different human FGF-2 isoforms in C6 rat glioma cell line using a tetracycline-regulated expression system. Phenotypic modifications were analyzed in vitro and compared to untransfected cells or to cells over-expressing 18 kDa FGF-2 or all FGF-2 isoforms. In particular, we demonstrate that HMW FGF-2 has unique features in inhibiting glioma cell proliferation. HMW FGF-2 expressing cells showed a cell-cycle arrest at the G2M, demonstrating a role of HMW FGF-2 in controlling the entry in mitosis. Moreover, hydroxyurea was ineffective in blocking cells at themore » G1S boundary when HMW FGF-2 was expressed. We also show that the HMW FGF-2 isoforms inhibit 4E-BP1 phosphorylation at critical sites restoring the translation inhibitory activity of 4E-BP1. In vivo, inhibition of tumor growth was observed when cells expressed HMW FGF-2. This indicates that HMW FGF-2 inhibits tumor growth in glioma cells by acting on cell-cycle progression and protein translation.« less

Phytomedicines and Nutraceuticals: Alternative Therapeutics for Sickle Cell Anemia

PubMed Central

Imaga, Ngozi Awa

2013-01-01

Sickle cell anemia is a genetically inherited disease in which the “SS” individual possesses an abnormal beta globin gene. A single base substitution in the gene encoding the human β-globin subunit results in replacement of β6 glutamic acid by valine, leading to the devastating clinical manifestations of sickle cell disease. This substitution causes drastic reduction in the solubility of sickle cell hemoglobin (HbS) when deoxygenated. Under these conditions, the HbS molecules polymerize to form long crystalline intracellular mass of fibers which are responsible for the deformation of the biconcave disc shaped erythrocyte into a sickle shape. First-line clinical management of sickle cell anemia include, use of hydroxyurea, folic acid, amino acids supplementation, penicillinprophylaxis, and antimalarial prophylaxis to manage the condition and blood transfusions to stabilize the patient's hemoglobin level. These are quite expensive and have attendant risk factors. However, a bright ray of hope involving research into antisickling properties of medicinal plants has been rewarding. This alternative therapy using phytomedicines has proven to not only reduce crisis but also reverse sickling (in vitro). The immense benefits of phytomedicines and nutraceuticals used in the management of sickle cell anemia are discussed in this paper. PMID:23476125

Inhibitors incorporating zinc-binding groups target the GlcNAc-PI de-N-acetylase in Trypanosoma brucei, the causative agent of African sleeping sickness.

PubMed

Abdelwahab, Nuha Z; Crossman, Arthur T; Sullivan, Lauren; Ferguson, Michael A J; Urbaniak, Michael D

2012-03-01

Disruption of glycosylphosphatidylinositol biosynthesis is genetically and chemically validated as a drug target against the protozoan parasite Trypanosoma brucei, the causative agent of African sleeping sickness. The N-acetylglucosamine-phosphatidylinositol de-N-acetylase (deNAc) is a zinc metalloenzyme responsible for the second step of glycosylphosphatidylinositol biosynthesis. We recently reported the synthesis of eight deoxy-2-C-branched monosaccharides containing carboxylic acid, hydroxamic acid, or N-hydroxyurea substituents at the C2 position that may act as zinc-binding groups. Here, we describe the synthesis of a glucocyclitol-phospholipid incorporating a hydroxamic acid moiety and report the biochemical evaluation of the monosaccharides and the glucocyclitol-phospholipid as inhibitors of the trypanosome deNAc in the cell-free system and against recombinant enzyme. Monosaccharides with carboxylic acid or hydroxamic acid substituents were found to be the inhibitors of the trypanosome deNAc with IC(50) values 0.1-1.5mM and the glucocyclitol-phospholipid was found to be a dual inhibitor of the deNAc and the α1-4-mannose transferase with an apparent IC(50)= 19±0.5μm. © 2011 John Wiley & Sons A/S.

TAO kinases mediate activation of p38 in response to DNA damage

PubMed Central

Raman, Malavika; Earnest, Svetlana; Zhang, Kai; Zhao, Yingming; Cobb, Melanie H

2007-01-01

Thousand and one amino acid (TAO) kinases are Ste20p-related MAP kinase kinase kinases (MAP3Ks) that activate p38 MAPK. Here we show that the TAO kinases mediate the activation of p38 in response to various genotoxic stimuli. TAO kinases are activated acutely by ionizing radiation, ultraviolet radiation, and hydroxyurea. Full-length and truncated fragments of dominant negative TAOs inhibit the activation of p38 by DNA damage. Inhibition of TAO expression by siRNA also decreases p38 activation by these agents. Cells in which TAO kinases have been knocked down are less capable of engaging the DNA damage-induced G2/M checkpoint and display increased sensitivity to IR. The DNA damage kinase ataxia telangiectasia mutated (ATM) phosphorylates TAOs in vitro; radiation induces phosphorylation of TAO on a consensus site for phosphorylation by the ATM protein kinase in cells; and TAO and p38 activation is compromised in cells from a patient with ataxia telangiectasia that lack ATM. These findings indicate that TAO kinases are regulators of p38-mediated responses to DNA damage and are intermediates in the activation of p38 by ATM. PMID:17396146

Primary distal femur T-cell lymphoma after allogeneic haematopoietic stem cell transplantation for chronic myeloid leukaemia: a rare case report and literature review.

PubMed

Han, Qiaoyan; Sun, Miao; Wu, Lingyu; Chen, Jing; Wang, Wei; Liu, Chunhua; Chen, Haoyue; Du, Guibin

2014-04-01

Post-transplant lymphoproliferative disorders originating from T lymphocytes are a rare complication of allogeneic haematopoietic stem cell transplantation (allo-HSCT) that are not usually associated with Epstein-Barr virus infection. A male patient diagnosed at the age of 15 years with chronic myeloid leukaemia (in the chronic phase) was initially treated with oral hydroxyurea. The disease entered an accelerated phase when the patient was 22 years old. Complete remission was achieved after one course of homoharringtonine and cytarabine. The patient then underwent human leucocyte antigen-matched sibling donor allo-HSCT. Just over 6.5 years after the allo-HSCT, a second primary tumour was located in the distal femur and diagnosed as T-cell non-Hodgkin's lymphoma (stage IV, group B). This was treated with various chemotherapy and radiotherapy regimens, but the outcomes were poor and the disease progressed. The T-cell lymphoma invaded many sites, including the skeleton, spleen and skin, and the patient died within 8 months of the diagnosis. This current case report highlights the need for the early detection and prevention of subsequent primary malignancies after allo-HSCT.

Replication-mediated disassociation of replication protein A–XPA complex upon DNA damage: implications for RPA handing off

PubMed Central

Jiang, Gaofeng; Zou, Yue; Wu, Xiaoming

2013-01-01

RPA (replication protein A), the eukaryotic ssDNA (single-stranded DNA)-binding protein, participates in most cellular processes in response to genotoxic insults, such as NER (nucleotide excision repair), DNA, DSB (double-strand break) repair and activation of cell cycle checkpoint signalling. RPA interacts with XPA (xeroderma pigmentosum A) and functions in early stage of NER. We have shown that in cells the RPA–XPA complex disassociated upon exposure of cells to high dose of UV irradiation. The dissociation required replication stress and was partially attributed to tRPA hyperphosphorylation. Treatment of cells with CPT (camptothecin) and HU (hydroxyurea), which cause DSB DNA damage and replication fork collapse respectively and also leads to the disruption of RPA–XPA complex. Purified RPA and XPA were unable to form complex in vitro in the presence of ssDNA. We propose that the competition-based RPA switch among different DNA metabolic pathways regulates the dissociation of RPA with XPA in cells after DNA damage. The biological significances of RPA–XPA complex disruption in relation with checkpoint activation, DSB repair and RPA hyperphosphorylation are discussed. PMID:22578086

Deficiency of the Arabidopsis Helicase RTEL1 Triggers a SOG1-Dependent Replication Checkpoint in Response to DNA Cross-Links

PubMed Central

Hu, Zhubing; Cools, Toon; Kalhorzadeh, Pooneh; Heyman, Jefri; De Veylder, Lieven

2015-01-01

To maintain genome integrity, DNA replication is executed and regulated by a complex molecular network of numerous proteins, including helicases and cell cycle checkpoint regulators. Through a systematic screening for putative replication mutants, we identified an Arabidopsis thaliana homolog of human Regulator of Telomere Length 1 (RTEL1), which functions in DNA replication, DNA repair, and recombination. RTEL1 deficiency retards plant growth, a phenotype including a prolonged S-phase duration and decreased cell proliferation. Genetic analysis revealed that rtel1 mutant plants show activated cell cycle checkpoints, specific sensitivity to DNA cross-linking agents, and increased homologous recombination, but a lack of progressive shortening of telomeres, indicating that RTEL1 functions have only been partially conserved between mammals and plants. Surprisingly, RTEL1 deficiency induces tolerance to the deoxynucleotide-depleting drug hydroxyurea, which could be mimicked by DNA cross-linking agents. This resistance does not rely on the essential replication checkpoint regulator WEE1 but could be blocked by a mutation in the SOG1 transcription factor. Taken together, our data indicate that RTEL1 is required for DNA replication and that its deficiency activates a SOG1-dependent replication checkpoint. PMID:25595823

Inflammatory targets of therapy in sickle cell disease

PubMed Central

Owusu-Ansah, Amma; Ihunnah, Chibueze A.; Walker, Aisha L.; Ofori-Acquah, Solomon F.

2015-01-01

Sickle cell disease (SCD) is a monogenic globin disorder characterized by the production of a structurally abnormal hemoglobin (Hb) variant Hb S, which causes severe hemolytic anemia, episodic painful vaso-occlusion and ultimately end-organ damage. The primary disease pathophysiology is intracellular Hb S polymerization and consequent sickling of erythrocytes. It has become evident over several decades that a more complex disease process contributes to the myriad of clinical complications seen in SCD patients with inflammation playing a central role. Drugs targeting specific inflammatory pathways therefore offer an attractive therapeutic strategy to ameliorate many of the clinical events in SCD. In addition they are useful tools to dissecting the molecular and cellular mechanisms that promote individual clinical events, and for developing improved therapeutics to address more challenging clinical dilemmas such as refractoriness to opioids or hyperalgesia. Here, we discuss the prospect of targeting multiple inflammatory pathways implicated in the pathogenesis of SCD with a focus on new therapeutics, striving to link the actions of the anti-inflammatory agents to a defined pathobiology, and specific clinical manifestations of SCD. We also review the anti-inflammatory attributes and the cognate inflammatory targets of hydroxyurea, the only FDA approved drug for SCD. PMID:26226206

The interaction of hydroxyurea and ionizing radiation in human cervical carcinoma cells.

PubMed

Kuo, M L; Kunugi, K A; Lindstrom, M J; Kinsella, T J

1997-01-01

The results from prior in vitro and in vivo studies and recent phase 3 clinical trials suggest a significant potential role for hydroxyurea (HU) as a clinical radiosensitizer for cervix cancer. However, a detailed study of possible cellular mechanisms of radiosensitization in human cervix cancer cells as a consequence of dose and timing of HU and ionizing radiation (IR) has not been performed. This in vitro study analyses the interactions of HU and IR in a human cervical carcinoma cell line, Caski. Exponentially growing Caski cells were continuously exposed to clinically achievable but minimally cytotoxic concentrations of HU (0.3-3.0 mM) for various time intervals (6, 12, 18, 24, and 30 hours) up to one population doubling time either prior to or immediately following IR (2-8 Gy). The radiation survival data were analyzed using our modification of the linear-quadratic model to test for an interaction (greater than additive). The effects of HU alone, IR alone, and the combination on cell cycle progression and on apoptotic cell death in exponentially growing Caski cells were measured. We report a significant HU-IR interaction (radiosensitization) based on the sequence of HU exposure (post- > pre-IR) and with increasing concentrations of HU (0.3-3.0 mM), but no effect on radiosensitization with the duration of exposure to HU for up to one cell population doubling (6-30 hours). HU concentration has a significant effect on both alpha and beta linear-quadratic values in the post-IR sequences. Exposures of exponentially growing Caski cells to 1 mM and 3 mM HU alone result in a complete block in early S phase throughout the 30-hour exposure, while 0.3 mM HU causes a transient early S-phase block over the initial 12 to 18 hours of exposure. HU alone has no effect on cell cycle progression in G1 or G2/M populations but results in a large apoptotic population (31% following 1 mM HU x 30 hours), which appears to be the principal mechanism of drug cytotoxicity in these cells. IR alone (4 or 6 Gy) results in a significant G2 delay for 6 to 18 hours following IR but no G1 delay and a small apoptotic population at 30 hours post-IR (5.4% vs 2.1% in non-IR controls). The use of HU (0.3 or 1.0 mM) following IR (4 or 6 Gy) results in a significantly larger G2 delay compared with IR alone, but with only an additive effect on the apoptotic population. These in vitro data demonstrate that radiosensitization of Caski cells is more significant with post-IR exposures to clinically achievable concentrations of HU. This HU-IR interaction is associated with an increased G2 delay, suggesting a reduction in IR damage repair. However, this interaction appears to be independent of the cytotoxicity (principally by apoptosis) from HU alone.

Nitric oxide-dependent killing of aerobic, anaerobic and persistent Burkholderia pseudomallei

PubMed Central

Jones-Carson, Jessica; Laughlin, James R.; Stewart, Amanda L.; Voskuil, Martin I.; Vázquez-Torres, Andrés

2012-01-01

Burkholderia pseudomallei infections are fastidious to treat with conventional antibiotic therapy, often involving a combination of drugs and long-term regimes. Bacterial genetic determinants contribute to the resistance of B. pseudomallei to many classes of antibiotics. In addition, anaerobiosis and hypoxia in abscesses typical of melioidosis select for persistent populations of B. pseudomallei refractory to a broad spectrum of antibacterials. We tested the susceptibility of B. pseudomallei to the drugs hydroxyurea, spermine NONOate and DETA NONOate that release nitric oxide (NO). Our investigations indicate that B. pseudomallei are killed by NO in a concentration and time-dependent fashion. The cytoxicity of this diatomic radical against B. pseudomallei depends on both the culture medium and growth phase of the bacteria. Rapidly growing, but not stationary phase, B. pseudomallei are readily killed upon exposure to the NO donor spermine NONOate. NO also has excellent antimicrobial activity against anaerobic B. pseudomallei. In addition, persistent bacteria highly resistant to most conventional antibiotics are remarkably susceptible to NO. Sublethal concentrations of NO inhibited the enzymatic activity of [4Fe-4S]-cofactored aconitase of aerobic and anaerobic B. pseudomallei. The strong anti-B. pseudomallei activity of NO described herein merits further studies on the application of NO-based antibiotics for the treatment of melioidosis. PMID:22521523

Nitric oxide-dependent killing of aerobic, anaerobic and persistent Burkholderia pseudomallei.

PubMed

Jones-Carson, Jessica; Laughlin, James R; Stewart, Amanda L; Voskuil, Martin I; Vázquez-Torres, Andrés

2012-06-30

Burkholderia pseudomallei infections are fastidious to treat with conventional antibiotic therapy, often involving a combination of drugs and long-term regimes. Bacterial genetic determinants contribute to the resistance of B. pseudomallei to many classes of antibiotics. In addition, anaerobiosis and hypoxia in abscesses typical of melioidosis select for persistent populations of B. pseudomallei refractory to a broad spectrum of antibacterials. We tested the susceptibility of B. pseudomallei to the drugs hydroxyurea, spermine NONOate and DETA NONOate that release nitric oxide (NO). Our investigations indicate that B. pseudomallei are killed by NO in a concentration and time-dependent fashion. The cytoxicity of this diatomic radical against B. pseudomallei depends on both the culture medium and growth phase of the bacteria. Rapidly growing, but not stationary phase, B. pseudomallei are readily killed upon exposure to the NO donor spermine NONOate. NO also has excellent antimicrobial activity against anaerobic B. pseudomallei. In addition, persistent bacteria highly resistant to most conventional antibiotics are remarkably susceptible to NO. Sublethal concentrations of NO inhibited the enzymatic activity of [4Fe-4S]-cofactored aconitase of aerobic and anaerobic B. pseudomallei. The strong anti-B. pseudomallei activity of NO described herein merits further studies on the application of NO-based antibiotics for the treatment of melioidosis. Copyright © 2012 Elsevier Inc. All rights reserved.

Gamma-tubulin-containing abnormal centrioles are induced by insufficient Plk4 in human HCT116 colorectal cancer cells.

PubMed

Kuriyama, Ryoko; Bettencourt-Dias, Monica; Hoffmann, Ingrid; Arnold, Marc; Sandvig, Lisa

2009-06-15

Cancer cells frequently induce aberrant centrosomes, which have been implicated in cancer initiation and progression. Human colorectal cancer cells, HCT116, contain aberrant centrioles composed of disorganized cylindrical microtubules and displaced appendages. These cells also express unique centrosome-related structures associated with a subset of centrosomal components, including gamma-tubulin, centrin and PCM1. During hydroxyurea treatment, these abnormal structures become more abundant and undergo a change in shape from small dots to elongated fibers. Although gamma-tubulin seems to exist as a ring complex, the abnormal structures do not support microtubule nucleation. Several lines of evidence suggest that the fibers correspond to a disorganized form of centriolar microtubules. Plk4, a mammalian homolog of ZYG-1 essential for initiation of centriole biogenesis, is not associated with the gamma-tubulin-specific abnormal centrosomes. The amount of Plk4 at each centrosome was less in cells with abnormal centrosomes than cells without gamma-tubulin-specific abnormal centrosomes. In addition, the formation of abnormal structures was abolished by expression of exogenous Plk4, but not SAS6 and Cep135/Bld10p, which are downstream regulators required for the organization of nine-triplet microtubules. These results suggest that HCT116 cells fail to organize the ninefold symmetry of centrioles due to insufficient Plk4.

Novel cardiac protective effects of urea: from shark to rat

PubMed Central

Wang, Xintao; Wu, Lingyun; Aouffen, M'hamed; Mateescu, Mircea-Alexandru; Nadeau, Réginald; Wang, Rui

1999-01-01

This study was carried out to investigate novel cardioprotective effects of urea and the underlying mechanisms. The cardiac functions under oxidative stress were evaluated using Langendorff perfused isolated heart.Isolated dogfish shark hearts tolerated the oxidative stress generated by electrolysis (10 mA, 1 min) of the perfusion solution (n=4), and also showed normal cardiac functions during post-ischaemia reperfusion (n=4). The high concentration of urea (350 mM) in the heart perfusate was indispensable for maintaining the normal cardiac functions of the shark heart.Urea at 3–300 mM (n=4 for each group) protected the isolated rat heart against both electrolysis-induced heart damage and post-ischaemia reperfusion-induced cardiac injury.A concentration-dependent scavenging effect of urea (3–300 mM, n=4 for each group) against electrolysis-induced reactive oxygen species was also demonstrated in vitro.Urea derivatives as hydroxyurea, dimethylurea, and thiourea had antioxidant cardioprotective effect against the electrolysis-induced cardiac dysfunction of rat heart, but were not as effective as urea in suppressing the post-ischaemia reperfusion injury.Our results suggest that urea and its derivatives are potential antioxidant cardioprotective agents against oxidative stress-induced myocardium damage including the post-ischaemia reperfusion-induced injury. PMID:10602326

Transfusional iron overload in children with sickle cell anemia on chronic transfusion therapy for secondary stroke prevention.

PubMed

Kwiatkowski, Janet L; Cohen, Alan R; Garro, Julian; Alvarez, Ofelia; Nagasubramanian, Ramamorrthy; Sarnaik, Sharada; Thompson, Alexis; Woods, Gerald M; Schultz, William; Mortier, Nicole; Lane, Peter; Mueller, Brigitta; Yovetich, Nancy; Ware, Russell E

2012-02-01

Chronic transfusion reduces the risk of recurrent stroke in children with sickle cell anemia (SCA) but leads to iron loading. Management of transfusional iron overload in SCA has been reported as suboptimal [1], but studies characterizing monitoring and treatment practices for iron overload in children with SCA, particularly in recent years with the expansion of chelator options, are lacking. We investigated the degree of iron loading and treatment practices of 161 children with SCA receiving transfusions for a history of stroke who participated in the Stroke with Transfusions Changing to Hydroxyurea (SWiTCH) trial. Data obtained during screening, including past and entry liver iron concentration (LIC) measurements, ferritin values, and chelation were analyzed. The mean age at enrollment was 12.9 ± 4 years and the mean duration of transfusion was 7 ± 3.8 years. Baseline LIC (median 12.94 mg/g dw) and serum ferritin (median 3,164 ng/mL) were elevated. Chelation therapy was initiated after a mean of 2.6 years of transfusions. At study entry, 137 were receiving chelation, most of whom (90%) were receiving deferasirox. This study underscores the need for better monitoring of iron burden with timely treatment adjustments in chronically transfused children with SCA.

Allyl Isothiocyanate Arrests Cancer Cells in Mitosis, and Mitotic Arrest in Turn Leads to Apoptosis via Bcl-2 Protein Phosphorylation*

PubMed Central

Geng, Feng; Tang, Li; Li, Yun; Yang, Lu; Choi, Kyoung-Soo; Kazim, A. Latif; Zhang, Yuesheng

2011-01-01

Allyl isothiocyanate (AITC) occurs in many commonly consumed cruciferous vegetables and exhibits significant anti-cancer activities. Available data suggest that it is particularly promising for bladder cancer prevention and/or treatment. Here, we show that AITC arrests human bladder cancer cells in mitosis and also induces apoptosis. Mitotic arrest by AITC was associated with increased ubiquitination and degradation of α- and β-tubulin. AITC directly binds to multiple cysteine residues of the tubulins. AITC induced mitochondrion-mediated apoptosis, as shown by cytochrome c release from mitochondria to cytoplasm, activation of caspase-9 and caspase-3, and formation of TUNEL-positive cells. Inhibition of caspase-9 blocked AITC-induced apoptosis. Moreover, we found that apoptosis induction by AITC depended entirely on mitotic arrest and was mediated via Bcl-2 phosphorylation at Ser-70. Pre-arresting cells in G1 phase by hydroxyurea abrogated both AITC-induced mitotic arrest and Bcl-2 phosphorylation. Overexpression of a Bcl-2 mutant prevented AITC from inducing apoptosis. We further showed that AITC-induced Bcl-2 phosphorylation was caused by c-Jun N-terminal kinase (JNK), and AITC activates JNK. Taken together, this study has revealed a novel anticancer mechanism of a phytochemical that is commonly present in human diet. PMID:21778226

Epidemiology and treatment of relative anemia in children with sickle cell disease in sub-Saharan Africa.

PubMed

Bello-Manga, Halima; DeBaun, Michael R; Kassim, Adetola A

2016-11-01

Sickle cell disease (SCD) is the most common inherited hemoglobinopathy in the world, with the majority of cases in sub-Saharan Africa. Concomitant nutritional deficiencies, infections or exposure to environmental toxins exacerbate chronic anemia in children with SCD. The resulting relative anemia is associated with increased risk of strokes, poor cognitive function and impaired growth. It may also attenuate optimal response to hydroxyurea therapy, the only effective and practical treatment option for SCD in sub-Saharan Africa. This review will focus on the epidemiology, clinical sequelae, and treatment of relative anemia in children with SCD living in low and middle-income countries in sub-Saharan Africa. Areas covered: The causes and treatment of relative anemia in children with SCD in sub-Saharan Africa. The MEDLINE database was searched using medical subject headings (MeSH) and keywords for articles regarding relative anemia in children with SCD in sub-Saharan Africa. Expert commentary: Anemia due to nutritional deficiencies and infectious diseases such as helminthiasis and malaria are prevalent in sub-Saharan Africa. Their co-existence in children with SCD increases morbidity and mortality. Therefore, preventing, diagnosing and treating the underlying cause of this relative anemia will improve SCD-related outcomes in children in sub-Saharan Africa.

Foraging behaviour in Drosophila larvae: mushroom body ablation.

PubMed

Osborne, K A; de Belle, J S; Sokolowski, M B

2001-02-01

Drosophila larvae and adults exhibit a naturally occurring genetically based behavioural polymorphism in locomotor activity while foraging. Larvae of the rover morph exhibit longer foraging trails than sitters and forage between food patches, while sitters have shorter foraging trails and forage within patches. This behaviour is influenced by levels of cGMP-dependent protein kinase (PGK) encoded by the foraging (for) gene. Rover larvae have higher expression levels and higher PGK activities than do sitters. Here we discuss the importance of the for gene for studies of the mechanistic and evolutionary significance of individual differences in behaviour. We also show how structure-function analysis can be used to investigate a role for mushroom bodies in larval behaviour both in the presence and in the absence of food. Hydroxyurea fed to newly hatched larvae prevents the development of all post-embryonically derived mushroom body (MB) neuropil. This method was used to ablate MBs in rover and sitter genetic variants of foraging to test whether these structures mediate expression of the foraging behavioural polymorphism. We found that locomotor activity levels during foraging of both the rover and sitter larval morphs were not significantly influenced by MB ablation. Alternative hypotheses that may explain how variation in foraging behaviour is generated are discussed.

CD209-336A/G promotor polymorphism and its clinical associations in sickle cell disease Egyptian Pediatric patients.

PubMed

Afifi, Rasha Abdel-Raouf; Kamal, Dina; Sayed, Riham El; Ekladious, Sherif M M; Shaheen, Gehan H; Yousry, Sherif M; Hussein, Rania Elsayed

2018-06-01

To detect the frequency of CD209 A>G polymorphism in sickle cell disease (SCD) Egyptian patients and to evaluate the use of CD209 A>G polymorphism as a genetic predictor of SCD clinical heterogeneity. A total of 100 Egyptian children with SCD and 100 Egyptian controls were tested for CD209 A>G polymorphism and were followed up prospectively between June 2012 and December 2014. Comparison of CD209 A>G polymorphism among cases and controls did not show statistically significant difference (p = .742). In addition, comparison of the allelic frequency did not show statistically significant difference (p = .738). Infections occurred more frequently among the heterozygous genotype (AG; 60.5%) and homozygous genotype (GG; 75%) patients than among the wild (AA) genotype (24.1%; p < .001). The use of hydroxyurea treatment was significantly higher among the wild (AA) genotype (47%) than the heterozygous (AG; 21%) and homozygous (GG; 5%) genotypes (p = .003). We found no significant difference between our population of Egyptian SCD cases and controls regarding CD209 A>G polymorphism. Infections occurred more frequently among the heterozygous genotype (AG) and homozygous genotype (GG) patients. Copyright © 2017. Published by Elsevier Ltd.

How I treat polycythemia vera.

PubMed

Passamonti, Francesco

2012-07-12

Polycythemia vera (PV) is a clonal disorder characterized by unwarranted production of red blood cells. In the majority of cases, PV is driven by oncogenic mutations that constitutively activate the JAK-STAT signal transduction pathway, such as JAK2 V617F, or exon 12 mutations or LNK mutations. Diagnosis of PV is based on the WHO criteria. Diagnosis of post-PV myelofibrosis is established according to the International Working Group for Myeloproliferative Neoplasms Research and Treatment criteria. Different clinical presentations of PV are discussed. Prognostication of PV is tailored to the most frequent complication during follow-up, namely, thrombosis. Age older than 60 years and prior history of thrombosis are the 2 main risk factors for disease stratification. Correlations are emerging between leukocytosis, JAK2(V617F) mutation, BM fibrosis, and different outcomes of PV, which need to be confirmed in prospective studies. In my practice, hydroxyurea is still the "gold standard" when cytoreduction is needed, even though pegylated IFN-alfa-2a and ruxolitinib might be useful in particular settings. Results of phase 1 or 2 studies concerning these latter agents should however be confirmed by the ongoing randomized phase 3 clinical trials. In this paper, I discuss the main problems encountered in daily clinical practice with PV patients regarding diagnosis, prognostication, and therapy.

Checkpoint Defects Leading to Premature Mitosis Also Cause Endoreplication of DNA in Aspergillus nidulans

PubMed Central

De Souza, Colin P. C.; Ye, Xiang S.; Osmani, Stephen A.

1999-01-01

The G2 DNA damage and slowing of S-phase checkpoints over mitosis function through tyrosine phosphorylation of NIMXcdc2 in Aspergillus nidulans. We demonstrate that breaking these checkpoints leads to a defective premature mitosis followed by dramatic rereplication of genomic DNA. Two additional checkpoint functions, uvsB and uvsD, also cause the rereplication phenotype after their mutation allows premature mitosis in the presence of low concentrations of hydroxyurea. uvsB is shown to encode a rad3/ATR homologue, whereas uvsD displays homology to rad26, which has only previously been identified in Schizosaccharomyces pombe. uvsBrad3 and uvsDrad26 have G2 checkpoint functions over mitosis and another function essential for surviving DNA damage. The rereplication phenotype is accompanied by lack of NIMEcyclinB, but ectopic expression of active nondegradable NIMEcyclinB does not arrest DNA rereplication. DNA rereplication can also be induced in cells that enter mitosis prematurely because of lack of tyrosine phosphorylation of NIMXcdc2 and impaired anaphase-promoting complex function. The data demonstrate that lack of checkpoint control over mitosis can secondarily cause defects in the checkpoint system that prevents DNA rereplication in the absence of mitosis. This defines a new mechanism by which endoreplication of DNA can be triggered and maintained in eukaryotic cells. PMID:10564263

Dopamine and Mushroom Bodies in Drosophila: Experience-Dependent and -Independent Aspects of Sexual Behavior

PubMed Central

Neckameyer, Wendi S.

1998-01-01

Depletion of dopamine in Drosophila melanogaster adult males, accomplished through systemic introduction of the tyrosine hydroxylase inhibitor 3-iodo-tyrosine, severely impaired the ability of these flies to modify their courtship responses to immature males. Mature males, when first exposed to immature males, will perform courtship rituals; the intensity and duration of this behavior rapidly diminshes with time. Dopamine is also required for normal female sexual receptivity; dopamine-depleted females show increased latency to copulation. One kilobase of 5′ upstream information from the Drosophila tyrosine hydroxylase (DTH) gene, when fused to the Escherichia coli β-galactosidase reporter and transduced into the genome of Drosophila melanogaster, is capable of directing expression of the reporter gene in the mushroom bodies, which are believed to mediate learning acquisition and memory retention in flies. Ablation of mushroom bodies by treatment of newly hatched larva with hydroxyurea resulted in the inability of treated mature adult males to cease courtship when placed with untreated immature males. However, functional mushroom bodies were not required for the dopaminergic modulation of an innate behavior, female sexual receptivity. These data suggest that dopamine acts as a signaling molecule within the mushroom bodies to mediate a simple form of learning. PMID:10454380

Single molecule analysis of Trypanosoma brucei DNA replication dynamics

PubMed Central

Calderano, Simone Guedes; Drosopoulos, William C.; Quaresma, Marina Mônaco; Marques, Catarina A.; Kosiyatrakul, Settapong; McCulloch, Richard; Schildkraut, Carl L.; Elias, Maria Carolina

2015-01-01

Eukaryotic genome duplication relies on origins of replication, distributed over multiple chromosomes, to initiate DNA replication. A recent genome-wide analysis of Trypanosoma brucei, the etiological agent of sleeping sickness, localized its replication origins to the boundaries of multigenic transcription units. To better understand genomic replication in this organism, we examined replication by single molecule analysis of replicated DNA. We determined the average speed of replication forks of procyclic and bloodstream form cells and we found that T. brucei DNA replication rate is similar to rates seen in other eukaryotes. We also analyzed the replication dynamics of a central region of chromosome 1 in procyclic forms. We present evidence for replication terminating within the central part of the chromosome and thus emanating from both sides, suggesting a previously unmapped origin toward the 5′ extremity of chromosome 1. Also, termination is not at a fixed location in chromosome 1, but is rather variable. Importantly, we found a replication origin located near an ORC1/CDC6 binding site that is detected after replicative stress induced by hydroxyurea treatment, suggesting it may be a dormant origin activated in response to replicative stress. Collectively, our findings support the existence of more replication origins in T. brucei than previously appreciated. PMID:25690894

Single molecule analysis of Trypanosoma brucei DNA replication dynamics.

PubMed

Calderano, Simone Guedes; Drosopoulos, William C; Quaresma, Marina Mônaco; Marques, Catarina A; Kosiyatrakul, Settapong; McCulloch, Richard; Schildkraut, Carl L; Elias, Maria Carolina

2015-03-11

Eukaryotic genome duplication relies on origins of replication, distributed over multiple chromosomes, to initiate DNA replication. A recent genome-wide analysis of Trypanosoma brucei, the etiological agent of sleeping sickness, localized its replication origins to the boundaries of multigenic transcription units. To better understand genomic replication in this organism, we examined replication by single molecule analysis of replicated DNA. We determined the average speed of replication forks of procyclic and bloodstream form cells and we found that T. brucei DNA replication rate is similar to rates seen in other eukaryotes. We also analyzed the replication dynamics of a central region of chromosome 1 in procyclic forms. We present evidence for replication terminating within the central part of the chromosome and thus emanating from both sides, suggesting a previously unmapped origin toward the 5' extremity of chromosome 1. Also, termination is not at a fixed location in chromosome 1, but is rather variable. Importantly, we found a replication origin located near an ORC1/CDC6 binding site that is detected after replicative stress induced by hydroxyurea treatment, suggesting it may be a dormant origin activated in response to replicative stress. Collectively, our findings support the existence of more replication origins in T. brucei than previously appreciated. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Developmental analysis of the dopamine-containing neurons of the Drosophila brain

PubMed Central

Hartenstein, Volker; Cruz, Louie; Lovick, Jennifer K.; Guo, Ming

2016-01-01

The Drosophila dopaminergic (DA) system consists of a relatively small number of neurons clustered throughout the brain and ventral nerve cord. Previous work shows that clusters of DA neurons innervate different brain compartments, which in part accounts for functional diversity of the DA system. In this paper, we analyzed the association between DA neuron clusters and specific brain lineages, developmental and structural units of the Drosophila brain which provide a framework of connections that can be followed throughout development. The hatching larval brain contains six groups of primary DA neurons (born in the embryo), which we assign to six distinct lineages. We can show that all larval DA clusters persist into the adult brain. Some clusters increase in cell number during late larval stages while others do not become DA-positive until early pupa. Ablating neuroblasts with hydroxyurea (HU) prior to onset of larval proliferation (generates secondary neurons) confirms these added DA clusters are primary neurons born in the embryo, rather than secondary neurons. A single cluster that becomes DA-positive in the late pupa, PAM1/lineage DALcm1/2, forms part of a secondary lineage which can be ablated by larval HU application. By supplying lineage information for each DA cluster, our analysis promotes further developmental and functional analyses of this important system of neurons. PMID:27350102

P-body proteins regulate transcriptional rewiring to promote DNA replication stress resistance.

PubMed

Loll-Krippleber, Raphael; Brown, Grant W

2017-09-15

mRNA-processing (P-) bodies are cytoplasmic granules that form in eukaryotic cells in response to numerous stresses to serve as sites of degradation and storage of mRNAs. Functional P-bodies are critical for the DNA replication stress response in yeast, yet the repertoire of P-body targets and the mechanisms by which P-bodies promote replication stress resistance are unknown. In this study we identify the complete complement of mRNA targets of P-bodies during replication stress induced by hydroxyurea treatment. The key P-body protein Lsm1 controls the abundance of HHT1, ACF4, ARL3, TMA16, RRS1 and YOX1 mRNAs to prevent their toxic accumulation during replication stress. Accumulation of YOX1 mRNA causes aberrant downregulation of a network of genes critical for DNA replication stress resistance and leads to toxic acetaldehyde accumulation. Our data reveal the scope and the targets of regulation by P-body proteins during the DNA replication stress response.P-bodies form in response to stress and act as sites of mRNA storage and degradation. Here the authors identify the mRNA targets of P-bodies during DNA replication stress, and show that P-body proteins act to prevent toxic accumulation of these target transcripts.

Genetic variation in IL28B (IFNL3) and response to interferon-alpha treatment in myeloproliferative neoplasms.

PubMed

Lindgren, Marie; Samuelsson, Jan; Nilsson, Lars; Knutsen, Håvar; Ghanima, Waleed; Westin, Johan; Johansson, Peter L; Andréasson, Björn

2018-05-01

In myeloproliferative neoplasms (MPN), interferon-alpha (IFN-α) is an effective treatment with disease-modifying properties but currently with no clear predictors of treatment outcome. Recent genomewide association studies in chronic hepatitis C have found a strong influence of genetic polymorphism near the IL28B (IFNL3) gene in response to IFN-α treatment. In this study, we sought to evaluate the prognostic impact of IL28B rs12979860, rs8099917, and rs12980275 on IFN-α treatment response in myeloproliferative neoplasms. We retrospectively evaluated 100 patients with MPN treated with IFN-α. The hematologic treatment response on IFN-α was compared between patients and correlated with host genetic variations in IL28B. The genotypes of IL28B were determined by allelic discrimination assays. The CC genotype of rs12979860 was found significantly associated with hematologic response in polycythemia vera (PV) with a complete response (CR) in 79% (CC) compared to 48% (non-CC), (P = .036). No association between the genotypes and treatment response on hydroxyurea was found. These results imply an effect of IL28B genotype on the outcome of IFN-α treatment in MPN. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Hypomorphism in human NSMCE2 linked to primordial dwarfism and insulin resistance

PubMed Central

Payne, Felicity; Colnaghi, Rita; Rocha, Nuno; Seth, Asha; Harris, Julie; Carpenter, Gillian; Bottomley, William E.; Wheeler, Eleanor; Wong, Stephen; Saudek, Vladimir; Savage, David; O’Rahilly, Stephen; Carel, Jean-Claude; Barroso, Inês; O’Driscoll, Mark; Semple, Robert

2014-01-01

Structural maintenance of chromosomes (SMC) complexes are essential for maintaining chromatin structure and regulating gene expression. Two the three known SMC complexes, cohesin and condensin, are important for sister chromatid cohesion and condensation, respectively; however, the function of the third complex, SMC5–6, which includes the E3 SUMO-ligase NSMCE2 (also widely known as MMS21) is less clear. Here, we characterized 2 patients with primordial dwarfism, extreme insulin resistance, and gonadal failure and identified compound heterozygous frameshift mutations in NSMCE2. Both mutations reduced NSMCE2 expression in patient cells. Primary cells from one patient showed increased micronucleus and nucleoplasmic bridge formation, delayed recovery of DNA synthesis, and reduced formation of foci containing Bloom syndrome helicase (BLM) after hydroxyurea-induced replication fork stalling. These nuclear abnormalities in patient dermal fibroblast were restored by expression of WT NSMCE2, but not a mutant form lacking SUMO-ligase activity. Furthermore, in zebrafish, knockdown of the NSMCE2 ortholog produced dwarfism, which was ameliorated by reexpression of WT, but not SUMO-ligase–deficient NSMCE. Collectively, these findings support a role for NSMCE2 in recovery from DNA damage and raise the possibility that loss of its function produces dwarfism through reduced tolerance of replicative stress. PMID:25105364

Hypomorphism in human NSMCE2 linked to primordial dwarfism and insulin resistance.

PubMed

Payne, Felicity; Colnaghi, Rita; Rocha, Nuno; Seth, Asha; Harris, Julie; Carpenter, Gillian; Bottomley, William E; Wheeler, Eleanor; Wong, Stephen; Saudek, Vladimir; Savage, David; O'Rahilly, Stephen; Carel, Jean-Claude; Barroso, Inês; O'Driscoll, Mark; Semple, Robert

2014-09-01

Structural maintenance of chromosomes (SMC) complexes are essential for maintaining chromatin structure and regulating gene expression. Two the three known SMC complexes, cohesin and condensin, are important for sister chromatid cohesion and condensation, respectively; however, the function of the third complex, SMC5-6, which includes the E3 SUMO-ligase NSMCE2 (also widely known as MMS21) is less clear. Here, we characterized 2 patients with primordial dwarfism, extreme insulin resistance, and gonadal failure and identified compound heterozygous frameshift mutations in NSMCE2. Both mutations reduced NSMCE2 expression in patient cells. Primary cells from one patient showed increased micronucleus and nucleoplasmic bridge formation, delayed recovery of DNA synthesis, and reduced formation of foci containing Bloom syndrome helicase (BLM) after hydroxyurea-induced replication fork stalling. These nuclear abnormalities in patient dermal fibroblast were restored by expression of WT NSMCE2, but not a mutant form lacking SUMO-ligase activity. Furthermore, in zebrafish, knockdown of the NSMCE2 ortholog produced dwarfism, which was ameliorated by reexpression of WT, but not SUMO-ligase-deficient NSMCE. Collectively, these findings support a role for NSMCE2 in recovery from DNA damage and raise the possibility that loss of its function produces dwarfism through reduced tolerance of replicative stress.

β2-spectrin depletion impairs DNA damage repair

PubMed Central

Horikoshi, Nobuo; Pandita, Raj K.; Mujoo, Kalpana; Hambarde, Shashank; Sharma, Dharmendra; Mattoo, Abid R.; Chakraborty, Sharmistha; Charaka, Vijaya; Hunt, Clayton R.; Pandita, Tej K.

2016-01-01

β2-Spectrin (β2SP/SPTBN1, gene SPTBN1) is a key TGF-β/SMAD3/4 adaptor and transcriptional cofactor that regulates TGF-β signaling and can contribute to liver cancer development. Here we report that cells deficient in β2-Spectrin (β2SP) are moderately sensitive to ionizing radiation (IR) and extremely sensitive to agents that cause interstrand cross-links (ICLs) or replication stress. In response to treatment with IR or ICL agents (formaldehyde, cisplatin, camptothecin, mitomycin), β2SP deficient cells displayed a higher frequency of cells with delayed γ-H2AX removal and a higher frequency of residual chromosome aberrations. Following hydroxyurea (HU)-induced replication stress, β2SP-deficient cells displayed delayed disappearance of γ-H2AX foci along with defective repair factor recruitment (MRE11, CtIP, RAD51, RPA, and FANCD2) as well as defective restart of stalled replication forks. Repair factor recruitment is a prerequisite for initiation of DNA damage repair by the homologous recombination (HR) pathway, which was also defective in β2SP deficient cells. We propose that β2SP is required for maintaining genomic stability following replication fork stalling, whether induced by either ICL damage or replicative stress, by facilitating fork regression as well as DNA damage repair by homologous recombination. PMID:27248179

Body Mass Index and the Association With Vaso-occlusive Crises in Pediatric Sickle Cell Disease.

PubMed

Zivot, Andrea; Apollonsky, Nataly; Gracely, Edward; Raybagkar, Deepti

2017-05-01

Children with sickle cell disease (SCD) historically have been underweight and have poor overall growth. Recent studies have demonstrated a trend toward obesity in pediatric SCD populations. Through retrospective chart review of patients with SCD followed at our center, we collected patient's data, including body mass index (BMI), weight percentiles, sickle cell genotype, baseline hemoglobin, medical and psychiatric comorbidities, 25-hydroxy vitamin D level, treatment with hydroxyurea, and chronic transfusions. We identified hospitalizations to St. Christopher's Hospital for vaso-occlusive crisis (VOC) and duration of hospitalization and intravenous opioid use were recorded. Student t test, Mann-Whitney U test, and analysis of variance were used to examine associations between variables and frequency and duration of hospitalizations for VOC. Among 328 patients with SCD, overweight and obese children constituted 19% of hospitalized and nonhospitalized patients. BMI status did not influence frequency (P=0.90) or duration of hospitalization (P=0.65) for VOC. Obesity was more associated with HbSC than HbSS (P=0.025) genotype. Our study did not demonstrate an association between extremes of BMI of patients and hospitalization for VOC. Considering current trend toward obesity, further prospective and interventional research are required to define the effects of extremes of BMI on pain crises in SCD.

Evaluation of Antioxidant and DNA Damage Protection Activity of the Hydroalcoholic Extract of Desmostachya bipinnata L. Stapf

PubMed Central

Bhimathati, Solomon Sunder Raj

2014-01-01

Desmostachya bipinnata Stapf (Poaceae/Gramineae) is an official drug of ayurvedic pharmacopoeia. Various parts of this plant were used extensively in traditional and folklore medicine to cure various human ailments. The present study was aimed to evaluate the antioxidant and DNA damage protection activity of hydroalcoholic extract of Desmostachya bipinnata both in vitro and in vivo, to provide scientific basis for traditional usage of this plant. The extract showed significant antioxidant activity in a dose-dependent manner with an IC50 value of 264.18 ± 3.47 μg/mL in H2O2 scavenging assay and prevented the oxidative damage to DNA in presence of DNA damaging agent (Fenton's reagent) at a concentration of 50 μg/mL. Also, the presence of extract protected yeast cells in a dose-dependent manner against DNA damaging agent (Hydroxyurea) in spot assay. Moreover, the presence of extract exhibited significant antioxidant activity in vivo by protecting yeast cells against oxidative stressing agent (H2O2). Altogether, the results of current study revealed that Desmostachya bipinnata is a potential source of antioxidants and lends pharmacological credence to the ethnomedical use of this plant in traditional system of medicine, justifying its therapeutic application for free-radical-induced diseases. PMID:24574873

Evaluation of antioxidant and DNA damage protection activity of the hydroalcoholic extract of Desmostachya bipinnata L. Stapf.

PubMed

Golla, Upendarrao; Bhimathati, Solomon Sunder Raj

2014-01-01

Desmostachya bipinnata Stapf (Poaceae/Gramineae) is an official drug of ayurvedic pharmacopoeia. Various parts of this plant were used extensively in traditional and folklore medicine to cure various human ailments. The present study was aimed to evaluate the antioxidant and DNA damage protection activity of hydroalcoholic extract of Desmostachya bipinnata both in vitro and in vivo, to provide scientific basis for traditional usage of this plant. The extract showed significant antioxidant activity in a dose-dependent manner with an IC50 value of 264.18±3.47  μg/mL in H2O2 scavenging assay and prevented the oxidative damage to DNA in presence of DNA damaging agent (Fenton's reagent) at a concentration of 50  μg/mL. Also, the presence of extract protected yeast cells in a dose-dependent manner against DNA damaging agent (Hydroxyurea) in spot assay. Moreover, the presence of extract exhibited significant antioxidant activity in vivo by protecting yeast cells against oxidative stressing agent (H2O2). Altogether, the results of current study revealed that Desmostachya bipinnata is a potential source of antioxidants and lends pharmacological credence to the ethnomedical use of this plant in traditional system of medicine, justifying its therapeutic application for free-radical-induced diseases.

The Exonuclease Homolog OsRAD1 Promotes Accurate Meiotic Double-Strand Break Repair by Suppressing Nonhomologous End Joining.

PubMed

Hu, Qing; Tang, Ding; Wang, Hongjun; Shen, Yi; Chen, Xiaojun; Ji, Jianhui; Du, Guijie; Li, Yafei; Cheng, Zhukuan

2016-10-01

During meiosis, programmed double-strand breaks (DSBs) are generated to initiate homologous recombination, which is crucial for faithful chromosome segregation. In yeast, Radiation sensitive1 (RAD1) acts together with Radiation sensitive9 (RAD9) and Hydroxyurea sensitive1 (HUS1) to facilitate meiotic recombination via cell-cycle checkpoint control. However, little is known about the meiotic functions of these proteins in higher eukaryotes. Here, we characterized a RAD1 homolog in rice (Oryza sativa) and obtained evidence that O. sativa RAD1 (OsRAD1) is important for meiotic DSB repair. Loss of OsRAD1 led to abnormal chromosome association and fragmentation upon completion of homologous pairing and synapsis. These aberrant chromosome associations were independent of OsDMC1. We found that classical nonhomologous end-joining mediated by Ku70 accounted for most of the ectopic associations in Osrad1 In addition, OsRAD1 interacts directly with OsHUS1 and OsRAD9, suggesting that these proteins act as a complex to promote DSB repair during rice meiosis. Together, these findings suggest that the 9-1-1 complex facilitates accurate meiotic recombination by suppressing nonhomologous end-joining during meiosis in rice. © 2016 American Society of Plant Biologists. All Rights Reserved.

Deficiency of the Arabidopsis helicase RTEL1 triggers a SOG1-dependent replication checkpoint in response to DNA cross-links.

PubMed

Hu, Zhubing; Cools, Toon; Kalhorzadeh, Pooneh; Heyman, Jefri; De Veylder, Lieven

2015-01-01

To maintain genome integrity, DNA replication is executed and regulated by a complex molecular network of numerous proteins, including helicases and cell cycle checkpoint regulators. Through a systematic screening for putative replication mutants, we identified an Arabidopsis thaliana homolog of human Regulator of Telomere Length 1 (RTEL1), which functions in DNA replication, DNA repair, and recombination. RTEL1 deficiency retards plant growth, a phenotype including a prolonged S-phase duration and decreased cell proliferation. Genetic analysis revealed that rtel1 mutant plants show activated cell cycle checkpoints, specific sensitivity to DNA cross-linking agents, and increased homologous recombination, but a lack of progressive shortening of telomeres, indicating that RTEL1 functions have only been partially conserved between mammals and plants. Surprisingly, RTEL1 deficiency induces tolerance to the deoxynucleotide-depleting drug hydroxyurea, which could be mimicked by DNA cross-linking agents. This resistance does not rely on the essential replication checkpoint regulator WEE1 but could be blocked by a mutation in the SOG1 transcription factor. Taken together, our data indicate that RTEL1 is required for DNA replication and that its deficiency activates a SOG1-dependent replication checkpoint. © 2015 American Society of Plant Biologists. All rights reserved.

Diminished origin licensing capacity specifically sensitises tumour cells to replication stress

PubMed Central

Zimmerman, Kristin M.; Jones, Rebecca M.; Petermann, Eva; Jeggo, Penelope A.

2013-01-01

Previous studies have shown that dormant licensed replication origins can be exploited to enhance recovery from replication stress. Since tumour cells express high levels of origin licensing proteins, we examined whether depletion of such factors might specifically sensitise tumour versus non-tumour cells. Consistent with previous findings, we observed that three tumour-derived cell lines overexpress ORC1, a licensing component, compared to four non-tumour cell lines and that a greater level of ORC1 was required to maintain viability in the tumour cells. We determined siRNA-mediated knockdown conditions for each line that maximally reduced ORC1 but did not impact upon viability, which we considered would optimally deplete dormant origins. ORC1 depletion hypersensitised the tumour-derived cells to hydroxyurea (HU) and H202 but did not affect the sensitivity of the non-tumour lines. Similar results were observed following depletion of ORC6 or CDC6. Further, co-depletion of p53 and ORC1 modestly impaired viability of 1BR3hTERT non-tumour fibroblasts and more dramatically caused hypersensitivity to HU. Finally, overexpression of the c-Myc oncogene combined with ORC1 depletion in non-tumour BJhTERT cells diminished viability. Collectively, these findings suggest that tumour cells may have a reliance on origin licensing capacity, suggesting that licensing factors could represent a target for drug-based cancer therapy. PMID:23364533

Caffeine stabilizes Cdc25 independently of Rad3 in S chizosaccharomyces pombe contributing to checkpoint override

PubMed Central

Alao, John P; Sjölander, Johanna J; Baar, Juliane; Özbaki-Yagan, Nejla; Kakoschky, Bianca; Sunnerhagen, Per

2014-01-01

Cdc25 is required for Cdc2 dephosphorylation and is thus essential for cell cycle progression. Checkpoint activation requires dual inhibition of Cdc25 and Cdc2 in a Rad3-dependent manner. Caffeine is believed to override activation of the replication and DNA damage checkpoints by inhibiting Rad3-related proteins in both S chizosaccharomyces pombe and mammalian cells. In this study, we have investigated the impact of caffeine on Cdc25 stability, cell cycle progression and checkpoint override. Caffeine induced Cdc25 accumulation in S . pombe independently of Rad3. Caffeine delayed cell cycle progression under normal conditions but advanced mitosis in cells treated with replication inhibitors and DNA-damaging agents. In the absence of Cdc25, caffeine inhibited cell cycle progression even in the presence of hydroxyurea or phleomycin. Caffeine induces Cdc25 accumulation in S . pombe by suppressing its degradation independently of Rad3. The induction of Cdc25 accumulation was not associated with accelerated progression through mitosis, but rather with delayed progression through cytokinesis. Caffeine-induced Cdc25 accumulation appears to underlie its ability to override cell cycle checkpoints. The impact of Cdc25 accumulation on cell cycle progression is attenuated by Srk1 and Mad2. Together our findings suggest that caffeine overrides checkpoint enforcement by inducing the inappropriate nuclear localization of Cdc25. PMID:24666325

Replication stress affects the fidelity of nucleosome-mediated epigenetic inheritance

PubMed Central

Li, Wenzhu; Yi, Jia; Agbu, Pamela; Zhou, Zheng; Kelley, Richard L.; Jia, Songtao

2017-01-01

The fidelity of epigenetic inheritance or, the precision by which epigenetic information is passed along, is an essential parameter for measuring the effectiveness of the process. How the precision of the process is achieved or modulated, however, remains largely elusive. We have performed quantitative measurement of epigenetic fidelity, using position effect variegation (PEV) in Schizosaccharomyces pombe as readout, to explore whether replication perturbation affects nucleosome-mediated epigenetic inheritance. We show that replication stresses, due to either hydroxyurea treatment or various forms of genetic lesions of the replication machinery, reduce the inheritance accuracy of CENP-A/Cnp1 nucleosome positioning within centromere. Mechanistically, we demonstrate that excessive formation of single-stranded DNA, a common molecular abnormality under these conditions, might have correlation with the reduction in fidelity of centromeric chromatin duplication. Furthermore, we show that replication stress broadly changes chromatin structure at various loci in the genome, such as telomere heterochromatin expanding and mating type locus heterochromatin spreading out of the boundaries. Interestingly, the levels of inheritable expanding at sub-telomeric heterochromatin regions are highly variable among independent cell populations. Finally, we show that HU treatment of the multi-cellular organisms C. elegans and D. melanogaster affects epigenetically programmed development and PEV, illustrating the evolutionary conservation of the phenomenon. Replication stress, in addition to its demonstrated role in genetic instability, promotes variable epigenetic instability throughout the epigenome. PMID:28749973

Rif1 is a global regulator of timing of replication origin firing in fission yeast

PubMed Central

Hayano, Motoshi; Kanoh, Yutaka; Matsumoto, Seiji; Renard-Guillet, Claire; Shirahige, Katsuhiko; Masai, Hisao

2012-01-01

One of the long-standing questions in eukaryotic DNA replication is the mechanisms that determine where and when a particular segment of the genome is replicated. Cdc7/Hsk1 is a conserved kinase required for initiation of DNA replication and may affect the site selection and timing of origin firing. We identified rif1Δ, a null mutant of rif1+, a conserved telomere-binding factor, as an efficient bypass mutant of fission yeast hsk1. Extensive deregulation of dormant origins over a wide range of the chromosomes occurs in rif1Δ in the presence or absence of hydroxyurea (HU). At the same time, many early-firing, efficient origins are suppressed or delayed in firing timing in rif1Δ. Rif1 binds not only to telomeres, but also to many specific locations on the arm segments that only partially overlap with the prereplicative complex assembly sites, although Rif1 tends to bind in the vicinity of the late/dormant origins activated in rif1Δ. The binding to the arm segments occurs through M to G1 phase in a manner independent of Taz1 and appears to be essential for the replication timing program during the normal cell cycle. Our data demonstrate that Rif1 is a critical determinant of the origin activation program on the fission yeast chromosomes. PMID:22279046

Faithful anaphase is ensured by Mis4, a sister chromatid cohesion molecule required in S phase and not destroyed in G1 phase

PubMed Central

Furuya, Kanji; Takahashi, Kohta; Yanagida, Mitsuhiro

1998-01-01

The loss of sister chromatid cohesion triggers anaphase spindle movement. The budding yeast Mcd1/Scc1 protein, called cohesin, is required for associating chromatids, and proteins homologous to it exist in a variety of eukaryotes. Mcd1/Scc1 is removed from chromosomes in anaphase and degrades in G1. We show that the fission yeast protein, Mis4, which is required for equal sister chromatid separation in anaphase is a different chromatid cohesion molecule that behaves independent of cohesin and is conserved from yeast to human. Its inactivation in G1 results in cell lethality in S phase and subsequent premature sister chromatid separation. Inactivation in G2 leads to cell death in subsequent metaphase–anaphase progression but missegregation occurs only in the next round of mitosis. Mis4 is not essential for condensation, nor does it degrade in G1. Rather, it associates with chromosomes in a punctate fashion throughout the cell cycle. mis4 mutants are hypersensitive to hydroxyurea (HU) and UV irradiation but retain the ability to restrain cell cycle progression when damaged or sustaining a block to replication. The mis4 mutation results in synthetic lethality with a DNA ligase mutant. Mis4 may form a stable link between chromatids in S phase that is split rather than removed in anaphase. PMID:9808627

Bilateral visual loss and cerebral infarction after spleen embolization in a trauma patient with idiopathic thrombocytopenic purpura: A case report.

PubMed

Wang, Wei-Ting; Li, Yu-Yu; Lin, Wan-Ching; Chen, Jen-Yin; Lan, Kuo-Mao; Sun, Cheuk-Kwan; Hung, Kuo-Chuan

2018-04-01

Splenic artery embolization (SAE) is a common procedure in trauma patients with blunt splenic injuries. We report a case of acute ischemic stroke following orthopedic surgery in a patient with post-SAE reactive thrombocytosis. A 37-year-old woman with idiopathic thrombocytopenic purpura (ITP) suffered from multiple trauma scheduled for open reduction and internal fixation for right tibial and left radius fracture five days after SAE. The patient did not have any thromboembolic complications, although the platelet counts increased from 43 × 10/L to 568 × 10/L within two days after SAE. Surgery was completed under general anesthesia with tracheal intubation without complications. The patient complained of visual loss followed by limb weakness on the fourth and eighth hour postoperatively. Magnetic resonance imaging (MRI) of head demonstrated ischemic change over bilateral basal ganglia, and occipital areas, suggesting the diagnosis of cortical blindness. To suppress platelet count and avoid platelet hyper-aggregation, anti-platelet drug (i.e., oral aspirin 100 mg daily), hydration, and hydroxyurea (i.e., 20 mg/kg daily) were used for the treatment of reactive thrombocytosis. Although right-sided hemiparesis persisted, the patient reported mild visual recovery. She was discharged four months after SAE with active rehabilitation. Our report highlights an increased risk of acute arterial thromboembolic events in patients with reactive thrombocytosis, especially those undergoing surgery.

Schizosaccharomyces pombe Hsk1p Is a Potential Cds1p Target Required for Genome Integrity

PubMed Central

Snaith, Hilary A.; Brown, Grant W.; Forsburg, Susan L.

2000-01-01

The fission yeast Hsk1p kinase is an essential activator of DNA replication. Here we report the isolation and characterization of a novel mutant allele of the gene. Consistent with its role in the initiation of DNA synthesis, hsk1ts genetically interacts with several S-phase mutants. At the restrictive temperature, hsk1ts cells suffer abnormal S phase and loss of nuclear integrity and are sensitive to both DNA-damaging agents and replication arrest. Interestingly, hsk1ts mutants released to the restrictive temperature after early S-phase arrest in hydroxyurea (HU) are able to complete bulk DNA synthesis but they nevertheless undergo an abnormal mitosis. These findings indicate a second role for hsk1 subsequent to HU arrest. Consistent with a later S-phase role, hsk1ts is synthetically lethal with Δrqh1 (RecQ helicase) or rad21ts (cohesin) mutants and suppressed by Δcds1 (RAD53 kinase) mutants. We demonstrate that Hsk1p undergoes Cds1p-dependent phosphorylation in response to HU and that it is a direct substrate of purified Cds1p kinase in vitro. These results indicate that the Hsk1p kinase is a potential target of Cds1p regulation and that its activity is required after replication initiation for normal mitosis. PMID:11027263

Chromatin Remodeling Factors Isw2 and Ino80 Regulate Checkpoint Activity and Chromatin Structure in S Phase

PubMed Central

Lee, Laura; Rodriguez, Jairo; Tsukiyama, Toshio

2015-01-01

When cells undergo replication stress, proper checkpoint activation and deactivation are critical for genomic stability and cell survival and therefore must be highly regulated. Although mechanisms of checkpoint activation are well studied, mechanisms of checkpoint deactivation are far less understood. Previously, we reported that chromatin remodeling factors Isw2 and Ino80 attenuate the S-phase checkpoint activity in Saccharomyces cerevisiae, especially during recovery from hydroxyurea. In this study, we found that Isw2 and Ino80 have a more pronounced role in attenuating checkpoint activity during late S phase in the presence of methyl methanesulfonate (MMS). We therefore screened for checkpoint factors required for Isw2 and Ino80 checkpoint attenuation in the presence of MMS. Here we demonstrate that Isw2 and Ino80 antagonize checkpoint activators and attenuate checkpoint activity in S phase in MMS either through a currently unknown pathway or through RPA. Unexpectedly, we found that Isw2 and Ino80 increase chromatin accessibility around replicating regions in the presence of MMS through a novel mechanism. Furthermore, through growth assays, we provide additional evidence that Isw2 and Ino80 partially counteract checkpoint activators specifically in the presence of MMS. Based on these results, we propose that Isw2 and Ino80 attenuate S-phase checkpoint activity through a novel mechanism. PMID:25701287

Cytological and molecular relationships between Larix decidua, L. leptolepis and Larix x eurolepis: identification of species-specific Chromosoms and synchronization of mitotic cells.

PubMed

Nkongolo, K K; Klimaszewska, K

1995-05-01

The effects of different concentrations of hydroxyurea (HU) and aphidicolin (APH) on the mitotic index (MI) were compared in cells of embryogenic cultures of Larix decidua, L. leptolepis, and L. decidua x L. leptolepis (Larix x eurolepis). The highest enhancement of the MI was obtained with HU at 1.25 mM and 0.6% colchicine. In general the MI decreased with an increase of HU or APH concentration (over 1.25 mM for HU and 5 μM for APH). Detailed karyotype analyses were made on the somatic complement of L. decidua, L. leptolepis, and their hybrid. These karyotypes were asymmetrical and advanced, with the smaller chromosomes being more submedian than the larger ones. The topography of chromosome 7 of L. decidua and chromosome 9 of L. leptolepis was found to be the most significant cytotaxonomic characteristic in differentiating these two species. Cytological data indicate that Japanese larch (L. leptolepis) is phylogenetically closer to European larch (L. decidua) than the Siberian larch group (L. sibirica and L. sukaczewii). Chromosomes with unusually long kinetochores were found in both species and the hybrid. Hyperploid cells (2n = 25) were observed in the hybrid (Larix x eurolepis) material analyzed. A genomic L. decidua probe hybridized strongly to dots of DNA from L. leptolepis indicating that there is high sequence homology between these two species.

Phase I study of magnesium pidolate in combination with hydroxycarbamide for children with sickle cell anaemia.

PubMed

Hankins, Jane S; Wynn, Lynn W; Brugnara, Carlo; Hillery, Cheryl A; Li, Chin-Shang; Wang, Winfred C

2008-01-01

In sickle cell anaemia, red cell dehydration increases intracellular HbS concentration and promotes sickling. Higher erythrocyte magnesium reduces water loss through negative regulation of membrane transporters. Hydroxycarbamide (also known as hydroxyurea) reduces sickling partly by increasing intracellular HbF. Combining drugs with distinct mechanisms could offer additive effects. A phase I trial combining oral magnesium pidolate and hydroxycarbamide was performed to estimate the maximum tolerated dose (MTD) and toxicity of magnesium. Cohorts of three children with HbSS, who were on a stable dose of hydroxycarbamide (median 28.5 mg/kg/d), received magnesium pidolate for 6 months beginning at 83 mg/kg/d. The dose was escalated by 50% for subsequent cohorts. Laboratory evaluations were performed at 0, 3, 6 and 9 months. Sixteen children (aged 4-12 years) participated. All four dose-limiting toxicities (grade III diarrhoea and abdominal pain) occurred within the first month of starting magnesium. Additionally, diarrhoea grades I (n = 1) and II (n = 3), and abdominal pain grade II (n = 3) occurred. Hydroxycarbamide dose reduction or interruption was not required. The MTD for magnesium pidolate used in combination with hydroxycarbamide was 125 mg/kg/d. KCl co-transporter activity declined after 3 months of magnesium pidolate (P = 0.02). A phase II study is needed to investigate the efficacy of this drug combination.

Novel insights in the management of sickle cell disease in childhood

PubMed Central

Iughetti, Lorenzo; Bigi, Elena; Venturelli, Donatella

2016-01-01

Sickle cell disease (SCD) is a life-threatening genetic disorder characterized by chronic hemolytic anemia, vascular injury and multiorgan dysfunctions. Over the last few decades, there have been significant improvements in SCD management in Western countries, especially in pediatric population. An early onset of prophylaxis with Penicillin and a proper treatment of the infections have increased the overall survival in childhood. Nevertheless, management of painful episodes and prevention of organ damage are still challenging and more efforts are needed to better understand the mechanisms behind the development of chronic organ damages. Hydroxyurea (Hydroxycarbamide, HU), the only medication approved as a disease-modifying agent by the United States Food and Drug Administration and the European Medicines Agency, is usually under-used, especially in developing countries. Currently, hematopoietic stem-cell transplantation is considered the only curative option, although its use is limited by lack of donors and transplant-related toxicity. SCD symptoms are similar in children and adults, but complications and systemic organ damages increase with age, leading to early mortality worldwide. Experts in comprehensive care of young patients with SCD, especially those approaching the transition age to adulthood, are missing, leading people to rely on urgent care, increasing health care utilization costs and inappropriate treatments. It would be important to establish programs of comprehensive healthcare for patients with SCD from birth to adulthood, to improve their quality and expectancy of life. PMID:26862499

Chk1 phosphorylation at Ser286 and Ser301 occurs with both stalled DNA replication and damage checkpoint stimulation.

PubMed

Ikegami, Yosuke; Goto, Hidemasa; Kiyono, Tohru; Enomoto, Masato; Kasahara, Kousuke; Tomono, Yasuko; Tozawa, Keiichi; Morita, Akimichi; Kohri, Kenjiro; Inagaki, Masaki

2008-12-26

We previously reported Chk1 to be phosphorylated at Ser286 and Ser301 by cyclin-dependent kinase (Cdk) 1 during mitosis [T. Shiromizu et al., Genes Cells 11 (2006) 477-485]. Here, we demonstrated that Chk1-Ser286 and -Ser301 phosphorylation also occurs in hydroxyurea (HU)-treated or ultraviolet (UV)-irradiated cells. Unlike the mitosis case, however, Chk1 was phosphorylated not only at Ser286 and Ser301 but also at Ser317 and Ser345 in the checkpoint response. Treatment with Cdk inhibitors diminished Chk1 phosphorylation at Ser286 and Ser301 but not at Ser317 and Ser345 with the latter. In vitro analyses revealed Ser286 and Ser301 on Chk1 to serve as two major phosphorylation sites for Cdk2. Immunoprecipitation analyses further demonstrated that Ser286/Ser301 and Ser317/Ser345 phosphorylation occur in the same Chk1 molecule during the checkpoint response. In addition, Ser286/Ser301 phosphorylation by Cdk2 was observed in Chk1 mutated to Ala at Ser317 and Ser345 (S317A/S345A), as well as Ser317/Ser345 phosphorylation by ATR was in S286A/S301A. Therefore, Chk1 phosphorylation in the checkpoint response is regulated not only by ATR but also by Cdk2.

Phosphatidylcholine catabolism in the MCF-7 cell cycle.

PubMed

Lin, Weiyang; Arthur, Gilbert

2006-10-01

The catabolism of phosphatidylcholine (PtdCho) appears to play a key role in regulating the net accumulation of the lipid in the cell cycle. Current protocols for measuring the degradation of PtdCho at specific cell-cycle phases require prolonged periods of incubation with radiolabelled choline. To measure the degradation of PtdCho at the S and G2 phases in the MCF-7 cell cycle, protocols were developed with radiolabelled lysophosphatidylcholine (lysoPtdCho), which reduces the labelling period and minimizes the recycling of labelled components. Although most of the incubated lysoPtdCho was hydrolyzed to glycerophosphocholine (GroPCho) in the medium, the kinetics of the incorporation of label into PtdCho suggests that the labelled GroPCho did not contribute significantly to cellular PtdCho formation. A protocol which involved exposing the cells twice to hydroxyurea, was also developed to produce highly synchronized MCF-7 cells with a profile of G1:S:G2/M of 90:5:5. An analysis of PtdCho catabolism in the synchronized cells following labelling with lysoPtdCho revealed that there was increased degradation of PtdCho in early to mid-S phase, which was attenuated in the G2/M phase. The results suggest that the net accumulation of PtdCho in MCF-7 cells may occur in the G2 phase of the cell cycle.

Clinical Features of 294 Turkish Patients with Chronic Myeloproliferative Neoplasms

PubMed Central

Andıç, Neslihan; Ünübol, Mustafa; Yağcı, Eren; Akay, Olga Meltem; Yavaşoğlu, İrfan; Kadıköylü, Vefki Gürhan; Bolaman, Ali Zahit

2016-01-01

Objective: Myeloproliferative neoplasms (MPNs) share common clonal stem cells but show significant differences in their clinical courses. The aim of this retrospective study was to evaluate thrombotic and hemorrhagic complications, JAK2 status, gastrointestinal and cardiac changes, treatment modalities, and survival in MPNs in Turkish patients. Materials and Methods: Medical files of 294 patients [112 essential thrombocythemia (ET), 117 polycythemia vera (PV), 46 primary myelofibrosis, and 19 unclassified MPN cases] from 2 different universities in Turkey were examined. Results: Older age, higher leukocyte count at diagnosis, and JAK2 mutation positivity were risk factors for thrombosis. Platelet count over 1000x109/L was a risk factor for hemorrhagic episodes. Hydroxyurea treatment was not related to leukemic transformation. Median follow-up time was 50 months (quartiles: 22.2-81.75) in these patients. Patients with primary myelofibrosis had the shortest survival of 137 months when compared with 179 months for ET and 231 months for PV. Leukemic transformation, thromboembolic events, age over 60 years, and anemia were found to be the factors affecting survival. Conclusion: Thromboembolic complications are the most important preventable risk factors for morbidity and mortality in MPNs. Drug management in MPNs is done according to hemoglobin and platelet counts. Based on the current study population our results support the idea that leukocytosis and JAK2 positivity are more important risk factors for thrombosis than hemoglobin and platelet values. PMID:27094255

Loss of neurogenesis in Hydra leads to compensatory regulation of neurogenic and neurotransmission genes in epithelial cells

PubMed Central

2016-01-01

Hydra continuously differentiates a sophisticated nervous system made of mechanosensory cells (nematocytes) and sensory–motor and ganglionic neurons from interstitial stem cells. However, this dynamic adult neurogenesis is dispensable for morphogenesis. Indeed animals depleted of their interstitial stem cells and interstitial progenitors lose their active behaviours but maintain their developmental fitness, and regenerate and bud when force-fed. To characterize the impact of the loss of neurogenesis in Hydra, we first performed transcriptomic profiling at five positions along the body axis. We found neurogenic genes predominantly expressed along the central body column, which contains stem cells and progenitors, and neurotransmission genes predominantly expressed at the extremities, where the nervous system is dense. Next, we performed transcriptomics on animals depleted of their interstitial cells by hydroxyurea, colchicine or heat-shock treatment. By crossing these results with cell-type-specific transcriptomics, we identified epithelial genes up-regulated upon loss of neurogenesis: transcription factors (Dlx, Dlx1, DMBX1/Manacle, Ets1, Gli3, KLF11, LMX1A, ZNF436, Shox1), epitheliopeptides (Arminins, PW peptide), neurosignalling components (CAMK1D, DDCl2, Inx1), ligand-ion channel receptors (CHRNA1, NaC7), G-Protein Coupled Receptors and FMRFRL. Hence epitheliomuscular cells seemingly enhance their sensing ability when neurogenesis is compromised. This unsuspected plasticity might reflect the extended multifunctionality of epithelial-like cells in early eumetazoan evolution. PMID:26598723

Loss of neurogenesis in Hydra leads to compensatory regulation of neurogenic and neurotransmission genes in epithelial cells.

PubMed

Wenger, Y; Buzgariu, W; Galliot, B

2016-01-05

Hydra continuously differentiates a sophisticated nervous system made of mechanosensory cells (nematocytes) and sensory-motor and ganglionic neurons from interstitial stem cells. However, this dynamic adult neurogenesis is dispensable for morphogenesis. Indeed animals depleted of their interstitial stem cells and interstitial progenitors lose their active behaviours but maintain their developmental fitness, and regenerate and bud when force-fed. To characterize the impact of the loss of neurogenesis in Hydra, we first performed transcriptomic profiling at five positions along the body axis. We found neurogenic genes predominantly expressed along the central body column, which contains stem cells and progenitors, and neurotransmission genes predominantly expressed at the extremities, where the nervous system is dense. Next, we performed transcriptomics on animals depleted of their interstitial cells by hydroxyurea, colchicine or heat-shock treatment. By crossing these results with cell-type-specific transcriptomics, we identified epithelial genes up-regulated upon loss of neurogenesis: transcription factors (Dlx, Dlx1, DMBX1/Manacle, Ets1, Gli3, KLF11, LMX1A, ZNF436, Shox1), epitheliopeptides (Arminins, PW peptide), neurosignalling components (CAMK1D, DDCl2, Inx1), ligand-ion channel receptors (CHRNA1, NaC7), G-Protein Coupled Receptors and FMRFRL. Hence epitheliomuscular cells seemingly enhance their sensing ability when neurogenesis is compromised. This unsuspected plasticity might reflect the extended multifunctionality of epithelial-like cells in early eumetazoan evolution. © 2015 The Authors.

Pentose Phosphate Pathway Function Affects Tolerance to the G-Quadruplex Binder TMPyP4

PubMed Central

Andrew, Elizabeth J.; Merchan, Stephanie; Lawless, Conor; Banks, A. Peter; Wilkinson, Darren J.; Lydall, David

2013-01-01

G-quadruplexes form in guanine-rich regions of DNA and the presence of these structures at telomeres prevents the activity of telomerase in vitro. Ligands such as the cationic porphyrin TMPyP4 stabilise G-quadruplexes and are therefore under investigation for their potential use as anti-cancer drugs. In order to investigate the mechanism of action of TMPyP4 in vivo, we carried out a genome-wide screen in the budding yeast Saccharomyces cerevisiae. We found that deletion of key pentose phosphate pathway (PPP) genes increased the sensitivity of yeast to the presence of TMPyP4. The PPP plays an important role in the oxidative stress response and sensitivity to TMPyP4 also increased when genes involved in the oxidative stress response, CCS1 and YAP1, were deleted. For comparison we also report genome wide-screens using hydrogen peroxide, which causes oxidative stress, RHPS4, another G-quadruplex binder and hydroxyurea, an S phase poison. We found that a number of TMPyP4-sensitive strains are also sensitive to hydrogen peroxide in a genome-wide screen. Overall our results suggest that treatment with TMPyP4 results in light-dependent oxidative stress response in budding yeast, and that this, rather than G-quadruplex binding, is the major route to cytotoxicity. Our results have implications for the usefulness and mechanism of action of TMPyP4. PMID:23776642

Current sickle cell disease management practices in Nigeria.

PubMed

Galadanci, N; Wudil, B J; Balogun, T M; Ogunrinde, G O; Akinsulie, A; Hasan-Hanga, F; Mohammed, A S; Kehinde, M O; Olaniyi, J A; Diaku-Akinwumi, I N; Brown, B J; Adeleke, S; Nnodu, O E; Emodi, I; Ahmed, S; Osegbue, A O; Akinola, N; Opara, H I O; Adegoke, S A; Aneke, J; Adekile, A D

2014-03-01

Although Nigeria has the highest burden of sickle cell disease (SCD) worldwide, there is still variable and poor utilisation of standard-of-care practices for SCD patients in the country. This was a questionnaire survey of doctors in some dedicated SCD clinics in Nigeria in order to document the facilities available and common management practices. There were responses from 18 clinics based in 11 institutions. The number of patients being followed in each centre ranged from 15 to approximately 11 000. All clinics provided malaria prophylaxis and folic acid routinely to their patients. Only eight clinics prescribe penicillin prophylaxis. Eight prescribe hydroxyurea to patients who can afford it when indicated. All of the centres except three have electronic cell counters, but all had access to haemoglobin electrophoresis. Three had high-performance liquid chromatography machines installed but none was being routinely used. One institution had a functioning molecular biology laboratory. There is no official newborn screening programme in the country. All had access to microbiology and chemistry laboratories. Nine institutions had CT, six had MRI and three had transcranial Doppler facilities. The care available for SCD in Nigeria is still suboptimal and there is an urgent need for concerted effort to tackle the problem, but to make a significant impact on the burden of the disease would require more focus at the primary care level. Some steps to achieving this are outlined.

Role of circulating granulocytes in sheep lung injury produced by phorbol myristate acetate.

PubMed

Dyer, E L; Snapper, J R

1986-02-01

Phorbol myristate acetate (PMA) and endotoxin cause pulmonary granulocyte sequestration and alteration in lung fluid and solute exchange in awake sheep that are felt to be analogous to the adult respiratory distress syndrome in humans. The basic hypothesis that PMA causes lung injury by activating circulating granulocytes has never been tested. The effects of infused PMA on lung mechanics and the cellular constituents of lung lymph have also not been reported. We therefore characterized the effects of intravenous PMA, 5 micrograms/kg, on lung mechanics, pulmonary hemodynamics, lung fluid and solute exchange, pulmonary gas exchange, blood and lymph leukocyte counts, and plasma and lymph cyclooxygenase products of arachidonate metabolism in 10 awake sheep with normal granulocyte counts and after granulocyte depletion with hydroxyurea. PMA significantly altered lung mechanics from base line in both nongranulocyte depleted and granulocyte-depleted sheep. Dynamic compliance decreased by over 50% and resistance to airflow across the lungs increased over threefold acutely following PMA infusion in both sets of experiments. Changes in lung mechanics, pulmonary hemodynamics, lung fluid and solute exchange, pulmonary gas exchange, and plasma and lymph arachidonate metabolites were not significantly affected by greater than 99% depletion of circulating granulocytes. We conclude that the lung injury caused by PMA in chronically instrumented awake sheep probably is not a result of activation of circulating granulocytes.

Brazilian Guidelines for transcranial doppler in children and adolescents with sickle cell disease

PubMed Central

Lobo, Clarisse Lopes de Castro; Cançado, Rodolfo Delfini; Leite, Ana Claudia Celestino Bezerra; dos Anjos, Ana Claudia Mendonça; Pinto, Ana Cristina Silva; Matta, Andre Palma da Cunha; Silva, Célia Maria; Silva, Gisele Sampaio; Friedrisch, João Ricardo; Braga, Josefina Aparecida Pellegrini; Lange, Marcos Christiano; Figueiredo, Maria Stella; Rugani, Marília Álvares; Veloso, Orlando; Moura, Patrícia Gomes; Cortez, Paulo Ivo; Adams, Robert; Gualandro, Sandra Fátima Menosi; de Castilho, Shirley Lopes; Thomé, Ursula; Zetola, Viviane Flumignan

2011-01-01

Background Sickle cell disease is the most common monogenic hereditary disease in Brazil. Although strokes are one of the main causes of morbidity and mortality in these patients, the use of transcranial Doppler to identify children at risk is not universally used. Objective To develop Brazilian guidelines for the use of transcranial Doppler in sickle cell disease children and adolescents, so that related health policies can be expanded, and thus contribute to reduce morbidity and mortality. Methods The guidelines were formulated in a consensus meeting of experts in transcranial Doppler and sickle cell disease. The issues discussed were previously formulated and scientific articles in databases (MEDLINE, SciELO and Cochrane) were carefully analyzed. The consensus for each question was obtained by a vote of experts on the specific theme. Results Recommendations were made, including indications for the use of transcranial Doppler according to the sickle cell disease genotype and patients age; the necessary conditions to perform the exam and its periodicity depending on exam results; the criteria for the indication of blood transfusions and iron chelation therapy; the indication of hydroxyurea; and the therapeutic approach in cases of conditional transcranial Doppler. Conclusion The Brazilian guidelines on the use of transcranial doppler in sickle cell disease patients may reduce the risk of strokes, and thus reduce the morbidity and mortality and improve the quality of life of sickle cell disease patients. PMID:23284243

Depression in sickle cell disease.

PubMed Central

Hasan, Syed Parwez; Hashmi, Shahzad; Alhassen, Mohammed; Lawson, William; Castro, Oswaldo

2003-01-01

PURPOSE: To assess the prevalence of depressive symptoms and examine the contribution of demographics, disease severity, and health care use variables to depressive symptoms in sickle cell patients who had been in stable health for at least one month. PATIENTS AND METHODS: Subjects were a convenience sample of 27 men and 23 women selected during a routine visit to the sickle cell clinic at Howard University Hospital. Depression was assessed using a cut-off score from the Beck Depression Inventory (BDI) and related to a variety of health outcomes. RESULTS: The results of the analyses indicate that 44% (n=22) of the sample scored within the mild to severe (>20) range of depression on the BDI. Depressed sickle cell patients were more frequently treated in emergency rooms and more likely to be hospitalized with vaso-occlusive crises. Patients more likely to be depressed were: those with low family income (<$10,000); less than high school education; female; those who had multiple blood transfusions; poor pain control; inadequate social support; hydroxyurea use; and had histories of frequent vaso-occlusive crises. CONCLUSION: The prevalence of depressive symptoms in sickle cell patients is high compared to the general African American population. Our findings confirmed previous studies examining the occurrence of depression in adults with sickle cell disease. Treatment of depression should be strongly considered to improve the quality of life and probably disease course in sickle cell patients. PMID:12911250

Centriolar satellite– and hMsd1/SSX2IP-dependent microtubule anchoring is critical for centriole assembly

PubMed Central

Hori, Akiko; Peddie, Christopher J.; Collinson, Lucy M.; Toda, Takashi

2015-01-01

Centriolar satellites are numerous electron-dense granules dispersed around the centrosome. Mutations in their components are linked to various human diseases, but their molecular roles remain elusive. In particular, the significance of spatial communication between centriolar satellites and the centrosome is unknown. hMsd1/SSX2IP localizes to both the centrosome and centriolar satellites and is required for tethering microtubules to the centrosome. Here we show that hMsd1/SSX2IP-mediated microtubule anchoring is essential for proper centriole assembly and duplication. On hMsd1/SSX2IP knockdown, the centriolar satellites become stuck at the microtubule minus end near the centrosome. Intriguingly, these satellites contain many proteins that normally localize to the centrosome. Of importance, microtubule structures, albeit not being anchored properly, are still required for the emergence of abnormal satellites, as complete microtubule depolymerization results in the disappearance of these aggregates from the vicinity of the centrosome. We highlighted, using superresolution and electron microscopy, that under these conditions, centriole structures are faulty. Remarkably, these cells are insensitive to Plk4 overproduction–induced ectopic centriole formation, yet they accelerate centrosome reduplication upon hydroxyurea arrest. Finally, the appearance of satellite aggregates is cancer cell specific. Together our findings provide novel insights into the mechanism of centriole assembly and microtubule anchoring. PMID:25833712

Markers of iron deficiency in patients with polycythemia vera receiving ruxolitinib or best available therapy.

PubMed

Verstovsek, Srdan; Harrison, Claire N; Kiladjian, Jean-Jacques; Miller, Carole; Naim, Ahmad B; Paranagama, Dilan C; Habr, Dany; Vannucchi, Alessandro M

2017-05-01

Polycythemia vera (PV) is characterized by erythropoiesis and JAK2-activating mutations, with increased risks of morbidity and mortality. Most patients with PV are iron deficient, and treatment often includes hematocrit control with phlebotomy, which may exacerbate iron deficiency-associated complications. The phase 3 RESPONSE trial evaluated the JAK1/JAK2 inhibitor ruxolitinib (n=110) versus best available therapy (BAT; n=112) in patients with PV who were hydroxyurea-resistant/intolerant. Ruxolitinib was superior to BAT for hematocrit control, reduction in splenomegaly, and blood count normalization. This exploratory analysis, the first to evaluate iron status in a prospective study of patients with PV, investigated ruxolitinib effects on 7 serum iron markers and iron deficiency-related patient-reported outcomes (PRO). Among patients with evidence of baseline iron deficiency, ruxolitinib was associated with normalization of iron marker levels, compared with lesser improvement with BAT. Iron levels remained stable in ruxolitinib patients with normal iron levels at baseline. Regardless of baseline iron status, treatment with ruxolitinib was associated with improvements in concentration problems, cognitive function, dizziness, fatigue, headaches, and inactivity, although improvements were generally greater among patients with baseline iron deficiency. The improvements in iron deficiency markers and PROs observed with ruxolitinib are suggestive of clinical benefits that warrant further exploration. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

The biphasic interphase-mitotic polarity of cell nuclei induced under DNA replication stress seems to be correlated with Pin2 localization in root meristems of Allium cepa.

PubMed

Żabka, Aneta; Trzaskoma, Paweł; Winnicki, Konrad; Polit, Justyna Teresa; Chmielnicka, Agnieszka; Maszewski, Janusz

2015-02-01

Long-term treatment of Allium cepa seedlings with low concentration of hydroxyurea (HU) results in a disruption of cell cycle checkpoints, leading root apex meristem (RAM) cells to an abnormal organization of nuclear structures forming interphase (I) and mitotic (M) domains of chromatin at opposite poles of the nucleus. Thus far, both critical cell length and an uneven distribution of cyclin B-like proteins along the nuclear axis have been recognized as essential factors needed to facilitate the formation of biphasic interphase-mitotic (IM) cells. Two new aspects with respect to their emergence are investigated in this study. The first concerns a relationship between the polarity of increasing chromatin condensation (IM orientation) and the acropetal (base→apex) alignment of RAM cell files. The second problem involves the effects of auxin (IAA), on the frequency of IM cells. We provide evidence that there is an association between the advanced M-poles of the IM cell nuclei and the polarized accumulation sites of auxin efflux carriers (PIN2 proteins) and IAA. Furthermore, our observations reveal exclusion regions for PIN2 proteins in the microtubule-rich structures, such as preprophase bands (PPBs) and phragmoplast. The current and previous studies have prompted us to formulate a hypothetical mechanism linking PIN2-mediated unilateral localization of IAA and the induction of bipolar IM cells in HU-treated RAMs of A. cepa. Copyright © 2014 Elsevier GmbH. All rights reserved.

The natural absence of RPA1N domain did not impair Leishmania amazonensis RPA-1 participation in DNA damage response and telomere protection.

PubMed

Da Silveira, Rita De Cássia Viveiros; Da Silva, Marcelo Santos; Nunes, Vinícius Santana; Perez, Arina Marina; Cano, Maria Isabel Nogueira

2013-04-01

We have previously shown that the subunit 1 of Leishmania amazonensis RPA (LaRPA-1) alone binds the G-rich telomeric strand and is structurally different from other RPA-1. It is analogous to telomere end-binding proteins described in model eukaryotes whose homologues were not identified in the protozoan´s genome. Here we show that LaRPA-1 is involved with damage response and telomere protection although it lacks the RPA1N domain involved with the binding with multiple checkpoint proteins. We induced DNA double-strand breaks (DSBs) in Leishmania using phleomycin. Damage was confirmed by TUNEL-positive nuclei and triggered a G1/S cell cycle arrest that was accompanied by nuclear accumulation of LaRPA-1 and RAD51 in the S phase of hydroxyurea-synchronized parasites. DSBs also increased the levels of RAD51 in non-synchronized parasites and of LaRPA-1 and RAD51 in the S phase of synchronized cells. More LaRPA-1 appeared immunoprecipitating telomeres in vivo and associated in a complex containing RAD51, although this interaction needs more investigation. RAD51 apparently co-localized with few telomeric clusters but it did not immunoprecipitate telomeric DNA. These findings suggest that LaRPA-1 and RAD51 work together in response to DNA DSBs and at telomeres, upon damage, LaRPA-1 works probably to prevent loss of single-stranded DNA and to assume a capping function.

The use of incentive spirometry in pediatric patients with sickle cell disease to reduce the incidence of acute chest syndrome.

PubMed

Ahmad, Fahd A; Macias, Charles G; Allen, Joseph Y

2011-08-01

To determine if incentive spirometry (IS) in pediatric patients admitted with sickle cell disease for nonrespiratory complaints will decrease acute chest syndrome (ACS). This was an Institutional Review Board-approved before-after 2-year retrospective cohort study evaluating an evidence-based guideline (EBG) initiating mandatory IS in admitted pediatric sickle cell patients from a tertiary children's emergency center. Student t testing and χ² analysis were performed. There were 1551 patient visits. About 258 visits were enrolled in the pre-EBG year, and 230 in the EBG year. Between year characteristics were similar. The EBG year reported higher use of hydroxyurea (P<0.01), analgesics (P=0.02), and chest pain (P=0.03). Sixty-seven patients (25.9%) in the pre-EBG year received transfusions versus 51 (22.5%) in the EBG year (NS). Twenty-five (9.6%) of the pre-EBG patients received blood for ACS versus 14 (6.1%) in the EBG group (absolute risk reduction: 3.5%, 95% confidence interval: -1-8.4%). Subgroup analysis revealed that patients who presented with back pain experienced a significant decrease in the development of ACS in the EBG year (P=0.04, absolute risk reduction: 14%, 95% confidence interval: 1-28%, number needed to treat: 8). Mandatory IS for sickle cell disease patients admitted without respiratory complaints reduces transfusions and ACS, particularly for those presenting with back pain.

Impact of sickle cell anaemia on cardiac chamber size in the paediatric population.

PubMed

Adjagba, Philippe M; Habib, Gaston; Robitaille, Nancy; Pastore, Yves; Raboisson, Marie-Josée; Curnier, Daniel; Dahdah, Nagib

2017-07-01

Purpose Sickle cell disease is known to cause various degrees of vasculopathy, including impact on heart function. The aims of this single-centre, retrospective study were to assess cardiac chamber size and function and the relationship with haematological indices such as haemoglobin, aspartate aminotransferase, reticulocytosis and bilirubin, lactate dehydrogenase in sickle cell disease. Right ventricle and left ventricle diastolic diameters, left ventricle mass estimate, left ventricle shortening fraction, myocardial performance index, and an index of myocardial relaxation (E/E') were calculated and correlated with haematological parameters. A total of 110 patients (65% haemoglobin SS, 29% haemoglobin SC) were studied at a mean age of 12.14±5.26 years. Right ventricle dilatation and left ventricle dilatation were present in 61.5 and 42.9%, respectively. Left ventricle mass was abnormal in 21.9%; all patients had normal myocardial performance index, 31.4% had abnormal E/E', and left ventricle shortening fraction was low in 38.1%. Cardiac dilatation was best correlated with haemoglobin, aspartate aminotransferase, reticulocytosis and bilirubin. Best subset regression analysis yielded significant additional prediction for right ventricle or left ventricle dilatation with haemoglobin, bilirubin, and lactate dehydrogenase. Abnormal E/E' was solely predictable with haemoglobin level. Hydroxyurea-treated patients had improved diastolic function. Right ventricle dilatation was more prevalent than left ventricle dilatation. The long-term consequences of right ventricular dilatation, clinical consequences, and association with pulmonary vasculopathy need to be further determined.

Correction of Murine Sickle Cell Disease Using γ-Globin Lentiviral Vectors to Mediate High-level Expression of Fetal Hemoglobin

PubMed Central

Pestina, Tamara I; Hargrove, Phillip W; Jay, Dennis; Gray, John T; Boyd, Kelli M; Persons, Derek A

2008-01-01

Increased levels of red cell fetal hemogloblin, whether due to hereditary persistence of expression or from induction with hydroxyurea therapy, effectively ameliorate sickle cell disease (SCD). Therefore, we developed erythroid-specific, γ-globin lentiviral vectors for hematopoietic stem cell (HSC)-targeted gene therapy with the goal of permanently increasing fetal hemoglobin (HbF) production in sickle red cells. We evaluated two different γ-globin lentiviral vectors for therapeutic efficacy in the BERK sickle cell mouse model. The first vector, V5, contained the γ-globin gene driven by 3.1 kb of β-globin regulatory sequences and a 130-bp β-globin promoter. The second vector, V5m3, was identical except that the γ-globin 3′-untranslated region (3′-UTR) was replaced with the β-globin 3′-UTR. Adult erythroid cells have β-globin mRNA 3′-UTR-binding proteins that enhance β-globin mRNA stability and we postulated this design might enhance γ-globin expression. Stem cell gene transfer was efficient and nearly all red cells in transplanted mice expressed human γ-globin. Both vectors demonstrated efficacy in disease correction, with the V5m3 vector producing a higher level of γ-globin mRNA which was associated with high-level correction of anemia and secondary organ pathology. These data support the rationale for a gene therapy approach to SCD by permanently enhancing HbF using a γ-globin lentiviral vector. PMID:19050697

Jab1 Mediates Protein Degradation of Rad9/Rad1/Hus1 Checkpoint Complex

PubMed Central

Huang, Jin; Yuan, Honglin; Lu, Chongyuan; Liu, Ximeng; Cao, Xu; Wan, Mei

2009-01-01

Summary The Rad1-Rad9-Hus1 (9-1-1) complex serves a dual role as a DNA-damage sensor in checkpoint signaling and as a mediator in DNA repair pathway. However, the intercellular mechanisms that regulate 9-1-1 complex are poorly understood. Jab1, the fifth component of the COP9 signalosome complex, plays a central role in the degradation of multiple proteins and is emerging as an important regulator in cancer development. Here, we tested the hypothesis that Jab1 controls the protein stability of the 9-1-1 complex via the proteosome pathway. We provide evidence that Jab1 physically associates with the 9-1-1 complex. This association is mediated through direct interaction between Jab1 and Rad1, one of the subunits of 9-1-1 complex. Importantly, Jab1 causes the translocation of the 9-1-1 complex from the nucleus to the cytoplasm, mediating rapid degradation of the 9-1-1 complex via 26S proteasome. Furthermore, Jab1 significantly suppresses checkpoint signaling activation, DNA synthesis recovery from blockage and cell viability after replication stresses such as UV exposure, γ radiation and hydroxyurea treatment. These results suggest that Jab1 is an important regulator for 9-1-1 protein stability control in cells, which may provide novel information on the involvement of Jab1 in checkpoint and DNA repair signaling in response to DNA damage. PMID:17583730

Function of the Plant DNA Polymerase Epsilon in Replicative Stress Sensing, a Genetic Analysis.

PubMed

Pedroza-García, José-Antonio; Mazubert, Christelle; Del Olmo, Ivan; Bourge, Mickael; Domenichini, Séverine; Bounon, Rémi; Tariq, Zakia; Delannoy, Etienne; Piñeiro, Manuel; Jarillo, José A; Bergounioux, Catherine; Benhamed, Moussa; Raynaud, Cécile

2017-03-01

Faithful transmission of the genetic information is essential in all living organisms. DNA replication is therefore a critical step of cell proliferation, because of the potential occurrence of replication errors or DNA damage when progression of a replication fork is hampered causing replicative stress. Like other types of DNA damage, replicative stress activates the DNA damage response, a signaling cascade allowing cell cycle arrest and repair of lesions. The replicative DNA polymerase ε (Pol ε) was shown to activate the S-phase checkpoint in yeast in response to replicative stress, but whether this mechanism functions in multicellular eukaryotes remains unclear. Here, we explored the genetic interaction between Pol ε and the main elements of the DNA damage response in Arabidopsis ( Arabidopsis thaliana ). We found that mutations affecting the polymerase domain of Pol ε trigger ATR-dependent signaling leading to SOG1 activation, WEE1-dependent cell cycle inhibition, and tolerance to replicative stress induced by hydroxyurea, but result in enhanced sensitivity to a wide range of DNA damaging agents. Using knock-down lines, we also provide evidence for the direct role of Pol ε in replicative stress sensing. Together, our results demonstrate that the role of Pol ε in replicative stress sensing is conserved in plants, and provide, to our knowledge, the first genetic dissection of the downstream signaling events in a multicellular eukaryote. © 2017 American Society of Plant Biologists. All Rights Reserved.

Sickle cell crisis: A crisis of a different sort?

PubMed

Kumar, Gurinder; Al Muwaijei, Ayesha Ateeq; Sohal, Aman Preet Singh

2018-01-20

: A 9-year-old boy with sickle cell disease (SCD) was presented to the emergency department with acute headache and swelling over his bilateral temporoparietal region. There was no history of antecedent trauma, fever, vomiting or other features of an intercurrent illness. On arrival, his blood pressure was 112/62 mm Hg, heart rate was 98/min and his Glasgow Coma Scale score was 15/15. There was evidence of significant scalp tenderness over the bilateral temporoparietal region. A complete neurological examination including direct and consensual pupillary response was unremarkable. Initial investigations revealed haemoglobin of 9.6 g/dL, leucocyte count of 6.8/mm 3 , platelet count of 219/mm 3 and a normal coagulation profile. His current medications included hydroxyurea and penicillin prophylaxis. He underwent an urgent CT of the head followed by MRI of the brain, which revealed abnormalities as depicted in figures 1,2.edpract;archdischild-2017-313899v1/F1F1F1Figure 1CT head.edpract;archdischild-2017-313899v1/F2F2F2Figure 2MRI brain. QUESTION 1: Is this one of the most common neurological presentation seen in sickle cell crisis? QUESTION 2: How common is this presentation in paediatric SCD? QUESTION 3: What is the best way to manage this child? © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Sickle cell disease

PubMed Central

2016-01-01

Introduction Sickle cell disease causes chronic haemolytic anaemia, dactylitis, and painful acute crises. It also increases the risk of stroke, organ damage, bacterial infections, and complications of blood transfusion. In sub-Saharan Africa, up to one third of adults are carriers of the defective sickle cell gene, and 1% to 2% of babies are born with the disease. Methods and outcomes We conducted a systematic overview, aiming to answer the following clinical question: What are the effects of pharmaceutical interventions to prevent sickle cell crisis and other acute complications in people with sickle cell disease? We searched: Medline, Embase, The Cochrane Library, and other important databases up to January 2015 (BMJ Clinical Evidence overviews are updated periodically; please check our website for the most up-to-date version of this overview). Results At this update, searching of electronic databases retrieved 369 studies. After deduplication and removal of conference abstracts, 136 records were screened for inclusion in the overview. Appraisal of titles and abstracts led to the exclusion of 99 studies and the further review of 37 full publications. Of the 37 full articles evaluated, three already included systematic reviews were updated, two systematic reviews, two RCTs, and one subsequent RCT were added at this update. We performed a GRADE evaluation for 12 PICO combinations. Conclusions In this systematic overview, we categorised the efficacy for five interventions based on information about the effectiveness and safety of antibiotic prophylaxis in children aged under 5 years, antibiotic prophylaxis in children aged 5 years or older, hydroxyurea, malaria chemoprophylaxis, and pneumococcal vaccines. PMID:26808098

Biologic properties of the thymocyte-activating factor (CETAF) produced by a rabbit corneal cell line (SIRC).

PubMed

Grabner, G; Luger, T A; Luger, B M; Smolin, G; Oh, J O

1983-05-01

Rabbit corneal epithelial cell cultures produce a cytokine (CETAF) that greatly enhances the proliferation of C3H/HeJ mouse thymocytes. The rabbit corneal cell line SIRC was used to generate CETAF activity in the culture supernatant. CETAF was then partially purified by Sephacryl S-200 gel filtration, where peaks of activity eluted in a molecular weight range of 95,000-55,000 (CETAF I) and 30,000-15,000 (CETAF II). Similar to the epidermal cell-derived thymocyte-activating factor (ETAF), CETAF (I and II) stimulated the growth of a human dermal fibroblast line (CRL 1445) in a dose-dependent manner, but failed to enhance the proliferation of an Interleukin 2 (IL 2)-dependent T-cell line (CT 6). Although CETAF did not exhibit any IL 2 activity, it clearly enhanced the IL 2 production by C3H/HeJ mouse splenocytes stimulated with suboptimal doses of lectins. Crude SIRC supernatants as well as the partially purified CETAF preparations showed a marked inhibition of polymorphonuclear neutrophil migration at high concentrations, but were significantly chemotactic when diluted samples were tested. CETAF release by SIRC cells was increased by stimulation with mitomycin C, phorbolmyristate acetate, hydroxyurea, silica, lipopolysaccaride B, and when the cells were cultured under serum-free conditions. These observations suggest that corneal epithelial cells may not only interact with the immune system in a way similar to keratinocytes, but may also stimulate corneal stromal cell through the production of CETAF.

Myeloid Blastic Transformation of Myeloproliferative Neoplasms – A Review of 112 Cases

PubMed Central

Noor, Syed J; Tan, Wei; Wilding, Gregory E; Ford, Laurie A; Barcos, Maurice; Sait, Sheila N J; Block, AnneMarie W; Thompson, James E; Wang, Eunice S; Wetzler, Meir

2010-01-01

Blastic transformation of myeloproliferative neoplasms (MPN) is still poorly understood. We describe a cohort of 23 Roswell Park Cancer Institute (RPCI) patients and 89 additional cases from the English literature for whom biologic features were described. We initially compared our 23 patients to the 89 cases from the literature. Our population had significantly less patients with prior history of polycythemia vera (PV), shorter time from MPN diagnosis to blastic transformation, <3 prior therapies, more frequent use of hydroxyurea and erythropoietin and less frequent use of alkylating agents. Interestingly, the overall survival of the two cohorts from the time of blastic transformation was similar. We therefore looked at the outcome of the entire cohort (n=112). Patients with prior history of essential thrombocythemia survived longer than patients with prior history of myelofibrosis or PV. Further, patients with <3 prior therapies, those who lacked complex karyotype and those <60 year old at MPN diagnosis had significantly longer survival. Among the PRCI population, 20/23 patients underwent induction treatment with cytarabine and an anthracycline containing regimens; 12 achieved remission and their overall survival was significantly longer than those who did not. Three patients underwent an allogeneic transplantation and their survival was significantly longer than those who did not. Patients with <3 prior therapies, those who lack complex karyotype and those <60 at MPN diagnosis have longer survival following blastic transformation. Finally, allogeneic transplantation represents the only chance for long-term survival in these patients. PMID:20727590

Psychosocial stressors of sickle cell disease on adult patients in Cameroon.

PubMed

Wonkam, Ambroise; Mba, Caryl Zameyo; Mbanya, Dora; Ngogang, Jeanne; Ramesar, Raj; Angwafo, Fru F

2014-12-01

Sickle Cell Disease (SCD) is a debilitating illness that affects quality of life. Studies of the psychosocial burden of SCD on patients have been rarely reported in Africa. We used a quantitative method, with face-to-face administered questionnaires, to study indices of psychosocial stressors on adult SCD patients in Cameroon. The questionnaire included a 36-item stress factors scale evaluating general perceptions of stress and five main stressors' domain: disease factors, hospital factors, financial factors, family factors and quality of personal-life factors. Items pertaining to psychosocial stressors involved four response options with increasing severity: 0, 1, 2 or 3. Non-parametric tests were used for analysis. The majority of the 83 participants were urban dwellers, female, 20-30 years old, single, unemployed, with at least a secondary or tertiary education. Median age at diagnosis was 100 months; 47.8% had >3 painful vaso-oclusive crises annually. Only 4.8% had been treated with hydroxyurea. The majority reported moderate to severe difficulty coping with SCD. The "degree of clinical severity" category displayed the highest median score (2.0), while familial stressors showed the lowest (0.8). Being female, married, with low education level, an additional affected sibling and low direct income were significantly associated with specific stressors' categories. In Cameroon, there is an urgent need to implement policies that ensure affordable access to health-care and practices to reduce SCD morbidity and improve patients' quality of life.

The detection of diverse aminoglycoside phosphotransferases within natural populations of actinomycetes.

PubMed

Anderson, A S; Clark, D J; Gibbons, P H; Sigmund, J M

2002-08-01

The conserved nature of the genes that code for actinomycete secondary metabolite biosynthetic pathways suggests a common evolutionary ancestor and incidences of lateral gene transfer. Resistance genes associated with these biosynthetic pathways also display a high degree of similarity. Actinomycete aminoglycoside phosphotransferase antibiotic resistance enzymes (APH) are coded for by such genes and are therefore good targets for evaluating the bioactive potential of actinomycetes. A set of universal PCR primers for APH encoding genes was used to probe genomic DNA from three collections of actinomycetes to determine the utility of molecular screening. An additional monitoring of populations for the predominance of specific classes of enzymes to predict the potential of environmental sites for providing isolates with interesting metabolic profiles. Approximately one-fifth of all isolates screened gave a positive result by PCR. The PCR products obtained were sequenced and compared to existing APH family members. Sequence analysis resolved the family into nine groups of which six had recognizable phenotypes: 6'-phosphotransferase (APH(6)), 3'-phosphotransferase (APH(3)), hydroxyurea phosphotransferase (HUR), peptide phosphotransferase, hygromycin B phosphotransferase (APH(7")) and oxidoreductase. The actinomycetes screened fell into seven groups, including three novel groups with unknown phenotypes. The strains clustered according to the environmental site from where they were obtained, providing evidence for the movement of these genes within populations. The value of this as a method for obtaining novel compounds and the significance to the ecology of antibiotic biosynthesis are discussed.

Sickle cell anemia induces changes in peripheral lymphocytes E-NTPDase/E-ADA activities and cytokines secretion in patients under treatment.

PubMed

Castilhos, Lívia G; Doleski, Pedro H; Bertoldo, Tatiana M D; Passos, Daniela F; Bertoncheli, Claudia de M; Rezer, João F P; Schlemmer, Josiane B; Leal, Daniela B R

2015-07-01

Sickle cell anemia (SCA) is characterized by hemoglobin polymerization that results in sickle-shaped red blood cells. The vascular obstruction by sickle erythrocytes is often inflammatory, and purinergic system ecto-enzymes play an important role in modulating the inflammatory and immune response. This study aimed to evaluate the E-NTPDase and E-ADA activities in lymphocytes of SCA treated patients, as well as verify the cytokine profile in this population. Fifteen SCA treated patients and 30 health subjects (control group) were selected. The peripheral lymphocytes were isolated and E-NTPDase and E-ADA activities were determined. Serum was separated from clot formation for the cytokines quantification. E-NTPDase (ATP and ADP as substrate) and E-ADA (adenosine as substrate) activities were increased in lymphocytes from SCA patients (P<0.001). The TNF-α and IL-6 serum cytokines showed decreased on SCA patients comparing to control (P<0.001). The regulation of extracellular nucleotides released in response to hypoxia and inflammation through E-NTPDase and E-ADA enzymes represent an important control of purine-mediated in the SCA disease, avoiding elevated adenosine levels in the extracellular medium and consequent organ injuries in these patients. The pro-inflammatory cytokines decreased levels by use of hydroxyurea occur in attempt to reduce the pro-inflammatory response and prevent vaso-oclusive crisis. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Transfusion Medicine in Sub-Saharan Africa: Conference Summary.

PubMed

Dzik, Walter Sunny; Kyeyune, Dorothy; Otekat, Grace; Natukunda, Bernard; Hume, Heather; Kasirye, Phillip G; Ddungu, Henry; Kajja, Isaac; Dhabangi, Aggrey; Mugyenyi, Godfrey R; Seguin, Claire; Barnes, Linda; Delaney, Meghan

2015-07-01

In November 2014, a 3-day conference devoted to transfusion medicine in sub-Saharan Africa was held in Kampala, Uganda. Faculty from academic institutions in Uganda provided a broad overview of issues pertinent to transfusion medicine in Africa. The conference consisted of lectures, demonstrations, and discussions followed by 5 small group workshops held at the Uganda Blood Transfusion Service Laboratories, the Ugandan Cancer Institute, and the Mulago National Referral Hospital. Highlighted topics included the challenges posed by increasing clinical demands for blood, the need for better patient identification at the time of transfusion, inadequate application of the antiglobulin reagent during pretransfusion testing, concern regarding proper recognition and evaluation of transfusion reactions, the expanded role for nurse leadership as a means to improve patient outcomes, and the need for an epidemiologic map of blood usage in Africa. Specialty areas of focus included the potential for broader application of transcranial Doppler and hydroxyurea therapy in sickle cell disease, African-specific guidelines for transfusion support of cancer patients, the challenges of transfusion support in trauma, and the importance of African-centered clinical research in pediatric and obstetric transfusion medicine. The course concluded by summarizing the benefits derived from an organized quality program that extended from the donor to the recipient. As an educational tool, the slide-audio presentation of the lectures will be made freely available at the International Society of Blood Transfusion Academy Web site: http://www.isbtweb.org/academy/. Copyright © 2015 Elsevier Inc. All rights reserved.

POB3 is required for both transcription and replication in the yeast Saccharomyces cerevisiae.

PubMed Central

Schlesinger, M B; Formosa, T

2000-01-01

Spt16 and Pob3 form stable heterodimers in Saccharomyces cerevisiae, and homologous proteins have also been purified as complexes from diverse eukaryotes. This conserved factor has been implicated in both transcription and replication and may affect both by altering the characteristics of chromatin. Here we describe the isolation and properties of a set of pob3 mutants and confirm that they have defects in both replication and transcription. Mutation of POB3 caused the Spt(-) phenotype, spt16 and pob3 alleles displayed severe synthetic defects, and elevated levels of Pob3 suppressed some spt16 phenotypes. These results are consistent with previous reports that Spt16 and Pob3 act in a complex that modulates transcription. Additional genetic interactions were observed between pob3 mutations and the genes encoding several DNA replication factors, including POL1, CTF4, DNA2, and CHL12. pob3 alleles caused sensitivity to the ribonucleotide reductase inhibitor hydroxyurea, indicating a defect in a process requiring rapid dNTP synthesis. Mutation of the S phase checkpoint gene MEC1 caused pob3 mutants to lose viability rapidly under restrictive conditions, revealing defects in a process monitored by Mec1. Direct examination of DNA contents by flow cytometry showed that S phase onset and progression were delayed when POB3 was mutated. We conclude that Pob3 is required for normal replication as well as for transcription. PMID:10924459

Inefficacy of piracetam in the prevention of painful crises in children and adolescents with sickle cell disease.

PubMed

Alvim, R C; Viana, M B; Pires, M A S; Franklin, H M O H; Paula, M J; Brito, A C; Oliveira, T F; Rezende, P V

2005-01-01

Analgesia and hydration remain the only safe treatment for painful crises of sickle cell disease; hydroxyurea is effective, but the toxicity is still a problem. Piracetam is a nootropic drug that has reportedly been effective and non-toxic in sickle cell patients, but most studies were not placebo-controlled and included a small number of patients. The present study evaluated the drug in a double-blind crossed placebo-controlled clinical trial in 73 children and adolescents suffering from moderate to severe painful crises for 13 months. Information regarding frequency and severity of pain was acquired through monthly clinical evaluation, visits and house calls, and 4,300 weekly questionnaires filled out by the patients in their domiciles. A monthly pain score was calculated for each patient. Pain was the most frequent adverse manifestation of the disease stressing its significant bio-psycho-social impact. Although nearly all patients and relatives reported a better clinical course throughout the whole study, the drug was ineffective in the prevention of painful crises. This placebo effect may be ascribed to an unplanned and unsystematic 'cognitive-behavioural' management of the children. The pain score in the second semester of the study - both in the experimental and in the control groups - was significantly smaller than that in the first semester. In conclusion, piracetam was found to be ineffective in the prevention of painful crises; a powerful placebo effect due to adequate patient care was demonstrated. Copyright (c) 2005 S. Karger AG, Basel

Efficient geometry optimization by Hellmann-Feynman forces with the anti-Hermitian contracted Schrödinger equation

NASA Astrophysics Data System (ADS)

Foley, Jonathan J.; Mazziotti, David A.

2010-10-01

An efficient method for geometry optimization based on solving the anti-Hermitian contracted Schrödinger equation (ACSE) is presented. We formulate a reduced version of the Hellmann-Feynman theorem (HFT) in terms of the two-electron reduced Hamiltonian operator and the two-electron reduced density matrix (2-RDM). The HFT offers a considerable reduction in computational cost over methods which rely on numerical derivatives. While previous geometry optimizations with numerical gradients required 2M evaluations of the ACSE where M is the number of nuclear degrees of freedom, the HFT requires only a single ACSE calculation of the 2-RDM per gradient. Synthesizing geometry optimization techniques with recent extensions of the ACSE theory to arbitrary electronic and spin states provides an important suite of tools for accurately determining equilibrium and transition-state structures of ground- and excited-state molecules in closed- and open-shell configurations. The ability of the ACSE to balance single- and multi-reference correlation is particularly advantageous in the determination of excited-state geometries where the electronic configurations differ greatly from the ground-state reference. Applications are made to closed-shell molecules N2, CO, H2O, the open-shell molecules B2 and CH, and the excited state molecules N2, B2, and BH. We also study the HCN ↔ HNC isomerization and the geometry optimization of hydroxyurea, a molecule which has a significant role in the treatment of sickle-cell anaemia.

A retrospective analysis of the impact of treatments and blood counts on survival and the risk of vascular events during the course of polycythaemia vera.

PubMed

Enblom-Larsson, Anneli; Girodon, Francois; Bak, Marie; Hersby, Ditte; Jooste, Valérie; Hasselbalch, Hans; Johansson, Peter; Andreasson, Björn

2017-06-01

Vascular and non-vascular complications are common in patients with polycythaemia vera. This retrospective study of 217 patients with polycythaemia vera aimed to determine whether blood counts with respect to different treatments influenced the complication rate and survival. We found that 78 (36%) patients suffered from at least one complication during follow-up. Older age and elevated lactate dehydrogenase at diagnosis were found to be risk factors for vascular complications. When the vascular complication occurred, 41% of the patients with a complication had elevated white blood cells (WBC) compared with 20% of patients without a complication (P = 0·042). Patients treated with hydroxycarbamide (HC; also termed hydroxyurea) experienced significantly fewer vascular complications (11%) than patients treated with phlebotomy only (27%) (P = 0·013). We also found a survival advantage for patients treated with HC, when adjusted for age, gender and time period of diagnosis (Hazard ratio for phlebotomy-treated patients compared to HC-treated patients at 5 years was 2·42, 95% confidence interval 1·03-5·72, P = 0·043). Concerning survival and vascular complications, HC-treated patients who needed at least one phlebotomy per year were not significantly different from HC-treated patients with a low phlebotomy requirement. We conclude that complementary phlebotomy in HC-treated patients in order to maintain the haematocrit, is safe. © 2017 John Wiley & Sons Ltd.

MAP kinase-signaling controls nuclear translocation of tripeptidyl-peptidase II in response to DNA damage and oxidative stress.

PubMed

Preta, Giulio; de Klark, Rainier; Chakraborti, Shankhamala; Glas, Rickard

2010-08-27

Reactive oxygen species (ROS) are a continuous hazard in eukaroytic cells by their ability to cause damage to biomolecules, in particular to DNA. Previous data indicated that the cytosolic serine peptidase tripeptidyl-peptidase II (TPPII) translocates into the nucleus of most tumor cell lines in response to gamma-irradiation and ROS production; an event that promoted p53 expression as well as caspase-activation. We here observed that nuclear translocation of TPPII was dependent on signaling by MAP kinases, including p38MAPK. Further, this was caused by several types of DNA-damaging drugs, a DNA cross-linker (cisplatinum), an inhibitor of topoisomerase II (etoposide), and to some extent also by nucleoside-analogues (5-fluorouracil, hydroxyurea). In the minority of tumor cell lines where TPPII was not translocated into the nucleus in response to DNA damage we observed reduced intracellular ROS levels, and the expression levels of redox defense systems were increased. Further, treatment with the ROS-inducer gamma-hexa-chloro-cyclohexane (gamma-HCH, lindane), an inhibitor of GAP junctions, restored nuclear translocation of TPPII in these cell lines upon gamma-irradiation. Moreover, blocking nuclear translocation of TPPII in etoposide-treated cells, by using a peptide-derived inhibitor (Z-Gly-Leu-Ala-OH), attenuated expression of gamma-H2AX in gamma-irradiated melanoma cells. Our results indicated a role for TPPII in MAPK-dependent DNA damage signaling. Copyright 2010 Elsevier Inc. All rights reserved.

Elp3 and Dph3 of Schizosaccharomyces pombe mediate cellular stress responses through tRNALysUUU modifications.

PubMed

Villahermosa, Desirée; Fleck, Oliver

2017-08-03

Efficient protein synthesis in eukaryotes requires diphthamide modification of translation elongation factor eEF2 and wobble uridine modifications of tRNAs. In higher eukaryotes, these processes are important for preventing neurological and developmental defects and cancer. In this study, we used Schizosaccharomyces pombe as a model to analyse mutants defective in eEF2 modification (dph1Δ), in tRNA modifications (elp3Δ), or both (dph3Δ) for sensitivity to cytotoxic agents and thermal stress. The dph3Δ and elp3Δ mutants were sensitive to a range of drugs and had growth defects at low temperature. dph3Δ was epistatic with dph1Δ for sensitivity to hydroxyurea and methyl methanesulfonate, and with elp3Δ for methyl methanesulfonate and growth at 16 °C. The dph1Δ and dph3Δ deletions rescued growth defects of elp3Δ in response to thiabendazole and at 37 °C. Elevated tRNA Lys UUU levels suppressed the elp3Δ phenotypes and some of the dph3Δ phenotypes, indicating that lack of tRNA Lys UUU modifications were responsible. Furthermore, we found positive genetic interactions of elp3Δ and dph3Δ with sty1Δ and atf1Δ, indicating that Elp3/Dph3-dependent tRNA modifications are important for efficient biosynthesis of key factors required for accurate responses to cytotoxic stress conditions.

Induction of homologous recombination following in utero exposure to DNA-damaging agents.

PubMed

Karia, Bijal; Martinez, Jo Ann; Bishop, Alexander J R

2013-11-01

Much of our understanding of homologous recombination, as well as the development of the working models for these processes, has been derived from extensive work in model organisms, such as yeast and fruit flies, and mammalian systems by studying the repair of induced double strand breaks or repair following exposure to genotoxic agents in vitro. We therefore set out to expand this in vitro work to ask whether DNA-damaging agents with varying modes of action could induce somatic change in an in vivo mouse model of homologous recombination. We exposed pregnant dams to DNA-damaging agents, conferring a variety of lesions at a specific time in embryo development. To monitor homologous recombination frequency, we used the well-established retinal pigment epithelium pink-eyed unstable assay. Homologous recombination resulting in the deletion of a duplicated 70 kb fragment in the coding region of the Oca2 gene renders this gene functional and can be visualized as a pigmented eyespot in the retinal pigment epithelium. We observed an increased frequency of pigmented eyespots in resultant litters following exposure to cisplatin, methyl methanesulfonate, ethyl methanesulfonate, 3-aminobenzamide, bleomycin, and etoposide with a contrasting decrease in the frequency of detectable reversion events following camptothecin and hydroxyurea exposure. The somatic genomic rearrangements that result from such a wide variety of differently acting damaging agents implies long-term potential effects from even short-term in utero exposures. Copyright © 2013 Elsevier B.V. All rights reserved.

Developmental Function in Toddlers With Sickle Cell Anemia

PubMed Central

Elkin, T. David; Brown, R. Clark; Glass, Penny; Rana, Sohail; Casella, James F.; Kalpatthi, Ram V.; Pavlakis, Steven; Mi, Zhibao; Wang, Winfred C.

2013-01-01

BACKGROUND: Neurocognitive impairment occurs in children and adults with sickle cell anemia, but little is known about neurodevelopment in very young children. We examined the neurodevelopmental status of infants participating in the Pediatric Hydroxyurea Phase III Clinical Trial (Baby Hug) to determine relationships with age, cerebral blood flow velocity, and hemoglobin concentration. METHODS: Standardized measures of infant neurodevelopment were administered to 193 infants with hemoglobin SS or hemoglobin S-β0 thalassemia between 7 and 18 months of age at the time of their baseline evaluation. Associations between neurodevelopmental scores and age, family income, parent education, hemoglobin concentration, and transcranial Doppler velocity were examined. RESULTS: Mean functioning on the baseline neurodevelopment scales was in the average range. There were no mental development scores <70 (impaired); 22 children had scores in the clinically significant range, 11 with impaired psychomotor scores and 11 with problematic behavior rating scores. Significantly poorer performance was observed with older age at baseline. Behavior rating scores were an average of 2.82 percentile points lower per month of age, with similar patterns observed with parent report using adaptive behavior scales. Parent-reported functional abilities and hemoglobin were negatively associated with higher transcranial Doppler velocities. CONCLUSIONS: Whereas overall functioning was in the normal range, behavioral and adaptive function was poorer with older age, even in this very young group of children. Explanatory mechanisms for this association between poorer developmental function and older age need to be identified. PMID:23296434

The transport kinetics and selectivity of HpUreI, the urea channel from Helicobacter pylori†

PubMed Central

Gray, Lawrence R; Gu, Sean X; Quick, Matthias; Khademi, Shahram

2017-01-01

Helicobacter pylori’s unique ability to colonize and survive in the acidic environment of the stomach is critically dependent on uptake of urea through the urea channel, HpUreI. Hence, HpUreI may represent a promising target for the development of specific drugs against this human pathogen. To obtain insight into the structure/function relationship of this channel, we have developed conditions for the high-yield expression and purification of stable recombinant HpUreI that allowed its detailed kinetic characterization in solubilized form and reconstituted into liposomes. Detergent-solubilized HpUreI forms homo-trimer, as determined by chemical cross-linking. Urea dissociation kinetics of purified HpUreI were determined by means of the scintillation proximity assay (SPA), whereas urea efflux was measured in HpUreI-containing proteoliposomes using stopped-flow spectrometry to determine the kinetics and selectivity of the urea channel. The kinetic analyses revealed that urea conduction in HpUreI is pH sensitive and saturable with a half-saturation concentration (or K0.5) of ~163 mM. Binding of urea by HpUreI was increased at lower pH; however, the apparent affinity of urea binding (~150 mM) was not significantly pH dependent. The solute selectivity analysis indicated that HpUreI is highly selective for urea and hydroxyurea. Removing either amino group of urea molecules diminishes their permeability through HpUreI. Similar to urea conduction, water diffusion through HpUreI is pH-dependent with low water permeability at neutral pH. PMID:21877689

Identification of ATR-Chk1 pathway inhibitors that selectively target p53-deficient cells without directly suppressing ATR catalytic activity

PubMed Central

Kawasumi, Masaoki; Bradner, James E.; Tolliday, Nicola; Thibodeau, Renee; Sloan, Heather; Brummond, Kay M.; Nghiem, Paul

2014-01-01

Resistance to DNA-damaging chemotherapy is a barrier to effective treatment that appears to be augmented by p53 functional deficiency in many cancers. In p53-deficient cells where the G1/S checkpoint is compromised, cell viability after DNA damage relies upon intact intra-S and G2/M checkpoints mediated by the ATR and Chk1 kinases. Thus, a logical rationale to sensitize p53-deficient cancers to DNA-damaging chemotherapy is through the use of ATP-competitive inhibitors of ATR or Chk1. To discover small molecules that may act on uncharacterized components of the ATR pathway, we performed a phenotype-based screen of 9,195 compounds for their ability to inhibit hydroxyurea-induced phosphorylation of Ser345 on Chk1, known to be a critical ATR substrate. This effort led to the identification of four small-molecule compounds, three of which were derived from known bioactive library (anthothecol, dihydrocelastryl, and erysolin) and one of which was a novel synthetic compound termed MARPIN. These compounds all inhibited ATR-selective phosphorylation and sensitized p53-deficient cancer cells to DNA-damaging agents in vitro and in vivo. Notably, these compounds did not inhibit ATR catalytic activity in vitro, unlike typical ATP-competitive inhibitors, but acted in a mechanistically distinct manner to disable ATR-Chk1 function. Our results highlight a set of novel molecular probes to further elucidate druggable mechanisms to improve cancer therapeutic responses produced by DNA-damaging drugs. PMID:25336189

Identification of ATR-Chk1 pathway inhibitors that selectively target p53-deficient cells without directly suppressing ATR catalytic activity.

PubMed

Kawasumi, Masaoki; Bradner, James E; Tolliday, Nicola; Thibodeau, Renee; Sloan, Heather; Brummond, Kay M; Nghiem, Paul

2014-12-15

Resistance to DNA-damaging chemotherapy is a barrier to effective treatment that appears to be augmented by p53 functional deficiency in many cancers. In p53-deficient cells in which the G1-S checkpoint is compromised, cell viability after DNA damage relies upon intact intra-S and G2-M checkpoints mediated by the ATR (ataxia telangiectasia and Rad3 related) and Chk1 kinases. Thus, a logical rationale to sensitize p53-deficient cancers to DNA-damaging chemotherapy is through the use of ATP-competitive inhibitors of ATR or Chk1. To discover small molecules that may act on uncharacterized components of the ATR pathway, we performed a phenotype-based screen of 9,195 compounds for their ability to inhibit hydroxyurea-induced phosphorylation of Ser345 on Chk1, known to be a critical ATR substrate. This effort led to the identification of four small-molecule compounds, three of which were derived from known bioactive library (anthothecol, dihydrocelastryl, and erysolin) and one of which was a novel synthetic compound termed MARPIN. These compounds all inhibited ATR-selective phosphorylation and sensitized p53-deficient cancer cells to DNA-damaging agents in vitro and in vivo. Notably, these compounds did not inhibit ATR catalytic activity in vitro, unlike typical ATP-competitive inhibitors, but acted in a mechanistically distinct manner to disable ATR-Chk1 function. Our results highlight a set of novel molecular probes to further elucidate druggable mechanisms to improve cancer therapeutic responses produced by DNA-damaging drugs. ©2014 American Association for Cancer Research.

Histone mRNA degradation in vivo: the first detectable step occurs at or near the 3' terminus.

PubMed Central

Ross, J; Peltz, S W; Kobs, G; Brewer, G

1986-01-01

The first detectable step in the degradation of human H4 histone mRNA occurs at the 3' terminus in a cell-free mRNA decay system (J. Ross and G. Kobs, J. Mol. Biol. 188:579-593, 1986). Most or all of the remainder of the mRNA is then degraded in a 3'-to-5' direction. The experiments described here were designed to determine whether a similar degradation pathway is followed in whole cells. Two sets of short-lived histone mRNA decay products were detected in logarithmically growing erythroleukemia (K562) cells. These products, designated the -5 and -12 RNAs, were generated by the loss of approximately 4 to 6 and 11 to 13 nucleotides, respectively, from the 3' terminus of histone mRNA. The same decay products were observed after a brief incubation in vitro. They were in low abundance or absent from cells that were not degrading histone mRNA. In contrast, they were readily detectable in cells that degraded the mRNA at an accelerated rate, i.e., in cells cultured with a DNA synthesis inhibitor, either cytosine arabinoside or hydroxyurea. During the initial stages of the decay process, as the 3' terminus of the mRNA was being degraded, the 5'-terminal region remained intact. These results indicate that the first detectable step in human H4 histone mRNA decay occurs at the 3' terminus and that degradation proceeds 3' to 5', both in cells and in cell-free reactions. Images PMID:3467177

Histone mRNA degradation in vivo: the first detectable step occurs at or near the 3' terminus.

PubMed

Ross, J; Peltz, S W; Kobs, G; Brewer, G

1986-12-01

The first detectable step in the degradation of human H4 histone mRNA occurs at the 3' terminus in a cell-free mRNA decay system (J. Ross and G. Kobs, J. Mol. Biol. 188:579-593, 1986). Most or all of the remainder of the mRNA is then degraded in a 3'-to-5' direction. The experiments described here were designed to determine whether a similar degradation pathway is followed in whole cells. Two sets of short-lived histone mRNA decay products were detected in logarithmically growing erythroleukemia (K562) cells. These products, designated the -5 and -12 RNAs, were generated by the loss of approximately 4 to 6 and 11 to 13 nucleotides, respectively, from the 3' terminus of histone mRNA. The same decay products were observed after a brief incubation in vitro. They were in low abundance or absent from cells that were not degrading histone mRNA. In contrast, they were readily detectable in cells that degraded the mRNA at an accelerated rate, i.e., in cells cultured with a DNA synthesis inhibitor, either cytosine arabinoside or hydroxyurea. During the initial stages of the decay process, as the 3' terminus of the mRNA was being degraded, the 5'-terminal region remained intact. These results indicate that the first detectable step in human H4 histone mRNA decay occurs at the 3' terminus and that degradation proceeds 3' to 5', both in cells and in cell-free reactions.

Short-chain carboxylic acids, a new class of teratogens: studies of potential biochemical mechanisms.

PubMed

Coakley, M E; Rawlings, S J; Brown, N A

1986-12-01

Certain short-chain carboxylic acids (SCCA) appear to share a common teratogenic potential, although the structural requirements for activity remain obscure. By using a whole rat embryo culture model system, several biochemical processes have been examined, either as potential initial sites of teratogenic action or as early steps in the pathway to malformation. Valproate, methoxyacetate, and butyrate were the prototype SCCA examined. Measurement of [14C]glucose utilization and lactate production confirmed that energy production by the early organogenesis embryo is predominantly from glycolysis. While the positive control agent, iodoacetate, caused a significant inhibition of lactate production, none of the SCCA affected this process or glucose utilization at teratogenic concentrations. Valproate did not influence embryonic acetyl CoA levels, in marked contrast to the reported response of adult liver, the other major target of valproate toxicity. Pinocytosis by the visceral yolk sac (VYS) was measured by the uptake of [125I]polyvinylpyrrolidone. This process ultimately supplies the embryo with amino-acids and is essential for normal development. SCCA induce morphological abnormalities of the VYS in embryo culture. Pinocytosis was slightly reduced by valporate, but not the other SCCA. However, comparison with the action of an antiserum, for which inhibition of pinocytosis is the initial teratogenic insult, suggests that this is not the mechanism for valproate. Incorporation of [3H]thymidine into embryo or yolk sac was not affected after 3 hr of SCCA exposure, but there was a marked effect of the positive control, hydroxyurea. This suggests that DNA synthesis is not directly influenced by SCCA.(ABSTRACT TRUNCATED AT 250 WORDS)

Short-chain carboxylic acids, a new class of teratogens: studies of potential biochemical mechanisms.

PubMed Central

Coakley, M E; Rawlings, S J; Brown, N A

1986-01-01

Certain short-chain carboxylic acids (SCCA) appear to share a common teratogenic potential, although the structural requirements for activity remain obscure. By using a whole rat embryo culture model system, several biochemical processes have been examined, either as potential initial sites of teratogenic action or as early steps in the pathway to malformation. Valproate, methoxyacetate, and butyrate were the prototype SCCA examined. Measurement of [14C]glucose utilization and lactate production confirmed that energy production by the early organogenesis embryo is predominantly from glycolysis. While the positive control agent, iodoacetate, caused a significant inhibition of lactate production, none of the SCCA affected this process or glucose utilization at teratogenic concentrations. Valproate did not influence embryonic acetyl CoA levels, in marked contrast to the reported response of adult liver, the other major target of valproate toxicity. Pinocytosis by the visceral yolk sac (VYS) was measured by the uptake of [125I]polyvinylpyrrolidone. This process ultimately supplies the embryo with amino-acids and is essential for normal development. SCCA induce morphological abnormalities of the VYS in embryo culture. Pinocytosis was slightly reduced by valporate, but not the other SCCA. However, comparison with the action of an antiserum, for which inhibition of pinocytosis is the initial teratogenic insult, suggests that this is not the mechanism for valproate. Incorporation of [3H]thymidine into embryo or yolk sac was not affected after 3 hr of SCCA exposure, but there was a marked effect of the positive control, hydroxyurea. This suggests that DNA synthesis is not directly influenced by SCCA.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3830097

How We Identify and Manage Patients with Inadequately Controlled Polycythemia Vera.

PubMed

Reiter, Andreas; Harrison, Claire

2016-10-01

Polycythemia vera (PV) is a chronic myeloproliferative neoplasm (MPN) characterized by an overactive Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway through mutations in JAK2 exons 12 or 14 (JAK2 V617F). The dominant clinical characteristics include erythrocytosis (with or without leukocytosis/thrombocytosis), thrombotic events, and symptoms. Increased risk of mortality is mainly caused by thrombotic events and progression to post-polycythemia vera myelofibrosis (PPV-MF) or secondary acute myeloid leukemia (sAML). The most important prognostic factors include age and a history of thrombotic events, although recent evidence has indicated that leukocytosis and additional cytogenetic aberrations may also be of significant prognostic value. First-line therapies include aspirin and phlebotomies, which significantly reduce the incidence of thrombotic events and prolong survival. Cytoreductive treatment with hydroxyurea (approved) and conventional or pegylated interferon-α (effective, but not approved in many countries) is initiated for high-risk or inadequately controlled disease, e.g., uncontrolled hematocrit, leukocytosis, thrombocytosis, thrombotic events, splenomegaly, or symptoms. However, some patients may not receive initial benefit from first-line therapy or may become resistant or intolerant in due course. Although second-line treatment options are limited, clinical trials have shown the efficacy of ruxolitinib toward improving blood counts, enlarged spleen, and symptoms and potentially reducing thrombotic events. Identification of patients with uncontrolled PV is important for clinical care, as such patients have a high risk of complications, and future studies with JAK inhibitors or other agents alone or in combination are needed to test their potential to reduce rates of thrombotic events and transformation to PPV-MF or sAML.

Bacterial Signaling Nucleotides Inhibit Yeast Cell Growth by Impacting Mitochondrial and Other Specifically Eukaryotic Functions

PubMed Central

Vergnano, Marta; Wan, Chris

2017-01-01

ABSTRACT We have engineered Saccharomyces cerevisiae to inducibly synthesize the prokaryotic signaling nucleotides cyclic di-GMP (cdiGMP), cdiAMP, and ppGpp in order to characterize the range of effects these nucleotides exert on eukaryotic cell function during bacterial pathogenesis. Synthetic genetic array (SGA) and transcriptome analyses indicated that, while these compounds elicit some common reactions in yeast, there are also complex and distinctive responses to each of the three nucleotides. All three are capable of inhibiting eukaryotic cell growth, with the guanine nucleotides exhibiting stronger effects than cdiAMP. Mutations compromising mitochondrial function and chromatin remodeling show negative epistatic interactions with all three nucleotides. In contrast, certain mutations that cause defects in chromatin modification and ribosomal protein function show positive epistasis, alleviating growth inhibition by at least two of the three nucleotides. Uniquely, cdiGMP is lethal both to cells growing by respiration on acetate and to obligately fermentative petite mutants. cdiGMP is also synthetically lethal with the ribonucleotide reductase (RNR) inhibitor hydroxyurea. Heterologous expression of the human ppGpp hydrolase Mesh1p prevented the accumulation of ppGpp in the engineered yeast and restored cell growth. Extensive in vivo interactions between bacterial signaling molecules and eukaryotic gene function occur, resulting in outcomes ranging from growth inhibition to death. cdiGMP functions through a mechanism that must be compensated by unhindered RNR activity or by functionally competent mitochondria. Mesh1p may be required for abrogating the damaging effects of ppGpp in human cells subjected to bacterial infection. PMID:28743817

Functions of Fun30 Chromatin Remodeler in Regulating Cellular Resistance to Genotoxic Stress

PubMed Central

Bi, Xin; Yu, Qun; Siler, Jasmine; Li, Chong; Khan, Ali

2015-01-01

The Saccharomyces cerevisiae Fun30 chromatin remodeler has recently been shown to facilitate long-range resection of DNA double strand break (DSB) ends, which proceeds homologous recombination (HR). This is believed to underlie the role of Fun30 in promoting cellular resistance to DSB inducing agent camptothecin. We show here that Fun30 also contributes to cellular resistance to genotoxins methyl methanesulfonate (MMS) and hydroxyurea (HU) that can stall the progression of DNA replication. We present evidence implicating DNA end resection in Fun30-dependent MMS-resistance. On the other hand, we show that Fun30 deletion suppresses the MMS- and HU-sensitivity of cells lacking the Rad5/Mms2/Ubc13-dependent error-free DNA damage tolerance mechanism. This suppression is not the result of a reduction in DNA end resection, and is dependent on the key HR component Rad51. We further show that Fun30 negatively regulates the recovery of rad5Δ mutant from MMS induced G2/M arrest. Therefore, Fun30 has two functions in DNA damage repair: one is the promotion of cellular resistance to genotoxic stress by aiding in DNA end resection, and the other is the negative regulation of a Rad51-dependent, DNA end resection-independent mechanism for countering replicative stress. The latter becomes manifest when Rad5 dependent DNA damage tolerance is impaired. In addition, we find that the putative ubiquitin-binding CUE domain of Fun30 serves to restrict the ability of Fun30 to hinder MMS- and HU-tolerance in the absence of Rad5. PMID:25806814

Pharmacotherapeutical strategies in the prevention of acute, vaso-occlusive pain in sickle cell disease: a systematic review

PubMed Central

Mager, David J.; Davis, Shyrin C. A. T.; Biemond, Bart J.

2017-01-01

Sickle-cell disease (SCD) is characterized by frequent and painful vaso-occlusive crises (VOCs). Various treatments have been evaluated over the years. However, a clear overview is lacking. The objective of this study was to systematically review all pharmacotherapeutical strategies in the prevention of VOCs beyond hydroxyurea. We performed a systematic literature search (MEDLINE, Embase, CENTRAL). Eligible studies were controlled clinical trials evaluating pharmacotherapeutical interventions targeting the reduction of VOCs in patients with SCD. Primary outcomes were the number or duration of SCD-related pain days, VOCs, or hospital admissions for VOCs. Secondary outcomes included time to first VOC or hospital admission for a VOC. A standardized data extraction sheet was used. The methodological quality of studies was assessed using Cochrane’s risk-of-bias tool. A total of 36 studies were included in this review, covering 26 different prophylactic interventions. The most promising interventions for reducing the frequency of either VOCs or hospitalizations were the oral antioxidants l-glutamine and ω-3 fatty acids and the IV antiadhesive agent crizanlizumab. Twenty-three studies did not show any beneficial effect of the intervention under investigation, and 6 studies were either too small or methodologically inadequate to draw conclusions. Because of the heterogeneity of interventions, no meta-analysis was performed. In conclusion, this review identified 3 promising pharmacotherapeutical strategies in the prevention of VOCs in SCD. Importantly, this study highlights the discrepancy between the significant burden of SCD worldwide and the low number of adequate trials performed. This review was registered at PROSPERO (CRD42015025250). PMID:29296801

Ribonucleotide reductase inhibition by metal complexes of Triapine (3-aminopyridine-2-carboxaldehyde thiosemicarbazone): A combined experimental and theoretical study

PubMed Central

Popović-Bijelić, Ana; Kowol, Christian R.; Lind, Maria E.S.; Luo, Jinghui; Himo, Fahmi; Enyedy, Éva A.; Arion, Vladimir B.; Gräslund, Astrid

2012-01-01

Triapine (3-aminopyridine-2-carboxaldehyde thiosemicarbazone, 3-AP) is currently the most promising chemotherapeutic compound among the class of α-N-heterocyclic thiosemicarbazones. Here we report further insights into the mechanism(s) of anticancer drug activity and inhibition of mouse ribonucleotide reductase (RNR) by Triapine. In addition to the metal-free ligand, its iron(III), gallium(III), zinc(II) and copper (II) complexes were studied, aiming to correlate their cytotoxic activities with their effects on the diferric/tyrosyl radical center of the RNR enzyme in vitro. In this study we propose for the first time a potential specific binding pocket for Triapine on the surface of the mouse R2 RNR protein. In our mechanistic model, interaction with Triapine results in the labilization of the diferric center in the R2 protein. Subsequently the Triapine molecules act as iron chelators. In the absence of external reductants, and in presence of the mouse R2 RNR protein, catalytic amounts of the iron(III)–Triapine are reduced to the iron(II)–Triapine complex. In the presence of an external reductant (dithiothreitol), stoichiometric amounts of the potently reactive iron (II)–Triapine complex are formed. Formation of the iron(II)–Triapine complex, as the essential part of the reaction outcome, promotes further reactions with molecular oxygen, which give rise to reactive oxygen species (ROS) and thereby damage the RNR enzyme. Triapine affects the diferric center of the mouse R2 protein and, unlike hydroxyurea, is not a potent reductant, not likely to act directly on the tyrosyl radical. PMID:21955844

Activation of the stress proteome as a mechanism for small molecule therapeutics.

PubMed

Brose, Rebecca Deering; Shin, Gloria; McGuinness, Martina C; Schneidereith, Tonya; Purvis, Shirley; Dong, Gao X; Keefer, Jeffrey; Spencer, Forrest; Smith, Kirby D

2012-10-01

Various small molecule pharmacologic agents with different known functions produce similar outcomes in diverse Mendelian and complex disorders, suggesting that they may induce common cellular effects. These molecules include histone deacetylase inhibitors, 4-phenylbutyrate (4PBA) and trichostatin A, and two small molecules without direct histone deacetylase inhibitor activity, hydroxyurea (HU) and sulforaphane. In some cases, the therapeutic effects of histone deacetylase inhibitors have been attributed to an increase in expression of genes related to the disease-causing gene. However, here we show that the pharmacological induction of mitochondrial biogenesis was necessary for the potentially therapeutic effects of 4PBA or HU in two distinct disease models, X-linked adrenoleukodystrophy and sickle cell disease. We hypothesized that a common cellular response to these four molecules is induction of mitochondrial biogenesis and peroxisome proliferation and activation of the stress proteome, or adaptive cell survival response. Treatment of human fibroblasts with these four agents induced mitochondrial and peroxisomal biogenesis as monitored by flow cytometry, immunofluorescence and/or western analyses. In treated normal human fibroblasts, all four agents induced the adaptive cell survival response: heat shock, unfolded protein, autophagic and antioxidant responses and the c-jun N-terminal kinase pathway, at the transcriptional and translational levels. Thus, activation of the evolutionarily conserved stress proteome and mitochondrial biogenesis may be a common cellular response to such small molecule therapy and a common basis of therapeutic action in various diseases. Modulation of this novel therapeutic target could broaden the range of treatable diseases without directly targeting the causative genetic abnormalities.

Activation of the stress proteome as a mechanism for small molecule therapeutics

PubMed Central

Brose, Rebecca Deering; Shin, Gloria; McGuinness, Martina C.; Schneidereith, Tonya; Purvis, Shirley; Dong, Gao X.; Keefer, Jeffrey; Spencer, Forrest; Smith, Kirby D.

2012-01-01

Various small molecule pharmacologic agents with different known functions produce similar outcomes in diverse Mendelian and complex disorders, suggesting that they may induce common cellular effects. These molecules include histone deacetylase inhibitors, 4-phenylbutyrate (4PBA) and trichostatin A, and two small molecules without direct histone deacetylase inhibitor activity, hydroxyurea (HU) and sulforaphane. In some cases, the therapeutic effects of histone deacetylase inhibitors have been attributed to an increase in expression of genes related to the disease-causing gene. However, here we show that the pharmacological induction of mitochondrial biogenesis was necessary for the potentially therapeutic effects of 4PBA or HU in two distinct disease models, X-linked adrenoleukodystrophy and sickle cell disease. We hypothesized that a common cellular response to these four molecules is induction of mitochondrial biogenesis and peroxisome proliferation and activation of the stress proteome, or adaptive cell survival response. Treatment of human fibroblasts with these four agents induced mitochondrial and peroxisomal biogenesis as monitored by flow cytometry, immunofluorescence and/or western analyses. In treated normal human fibroblasts, all four agents induced the adaptive cell survival response: heat shock, unfolded protein, autophagic and antioxidant responses and the c-jun N-terminal kinase pathway, at the transcriptional and translational levels. Thus, activation of the evolutionarily conserved stress proteome and mitochondrial biogenesis may be a common cellular response to such small molecule therapy and a common basis of therapeutic action in various diseases. Modulation of this novel therapeutic target could broaden the range of treatable diseases without directly targeting the causative genetic abnormalities. PMID:22752410

Gastrointestinal and hepatic complications of sickle cell disease.

PubMed

Ebert, Ellen C; Nagar, Michael; Hagspiel, Klaus D

2010-06-01

Sickle cell disease (SCD) is an autosomal recessive abnormality of the beta-globin chain of hemoglobin (Hb), resulting in poorly deformable sickled cells that cause microvascular occlusion and hemolytic anemia. The spleen is almost always affected by SCD, with microinfarcts within the first 36 months of life resulting in splenic atrophy. Acute liver disorders causing right-sided abdominal pain include acute vaso-occlusive crisis, liver infarction, and acute hepatic crisis. Chronic liver disease might be due to hemosiderosis and hepatitis and possibly to SCD itself if small, clinically silent microvascular occlusions occur chronically. Black pigment gallstones caused by elevated bilirubin excretion are common. Their small size permits them to travel into the common bile duct but cause only low-grade obstruction, so hyperbilirubinemia rather than bile duct dilatation is typical. Whether cholecystectomy should be done in asymptomatic individuals is controversial. The most common laboratory abnormality is an elevation of unconjugated bilirubin level. Bilirubin and lactate dehydrogenase levels correlate with one another, suggesting that chronic hemolysis and ineffective erythropoiesis, rather than liver disease, are the sources of hyperbilirubinemia. Abdominal pain is very common in SCD and is usually due to sickling, which resolves with supportive care. Computed tomography scans might be ordered for severe or unremitting pain. The liver typically shows sickled erythrocytes and Kupffer cell enlargement acutely and hemosiderosis chronically. The safety of liver biopsies has been questioned, particularly during acute sickling crisis. Treatments include blood transfusions, exchange transfusions, iron-chelating agents, hydroxyurea, and allogeneic stem-cell transplantation. Copyright 2010 AGA Institute. Published by Elsevier Inc. All rights reserved.

[A rare case of myeloproliferative disease with t(8;13)(p11;q12) associated with eosinophilia and lymphadenopathy].

PubMed

Tsyba, N N; Turkina, A G; Chelysheva, E Yu; Nemchenko, I S; Kovrigina, A M; Obukhova, T N; Urnova, E S; Kuzmina, L A; Savchenko, V G

Myeloproliferative disease associated with FGFR1 rearrangement (8p11), which is included in the 2008 WHO Classification of Myeloid Neoplasms, is a rare and extremely aggressive abnormality. The paper describes a clinical case of a 39-year-old female patient who was detected to have leukocytosis (as high as 47.2·109/l), absolute eosinophilia (as high as 3.1·109/l), and enlarged peripheral lymph nodes during her visit to a doctor. The bone marrow (BM) showed the changes typically encountered in myeloproliferative disease with eosinophilia. The patient was found to have t(8;13)(p11;q12) translocation associated with the rearrangement of the FGFR1 gene located at the 8p11 locus. Molecular and cytogenetic examinations failed to reveal BCR-ABL chimeric transcript, Jak2 V617F mutation, and deletions and translocations involving PDGFRA (4q12) and PDGFRB (5q32-33). The similar changes in the karyotype were also found in the lymph node cells. The undertaken treatment with hydroxyurea and the tyrosine kinase inhibitor dasatinib turned out to be ineffective. The patient underwent allogeneic BM transplantation from a HLA-identical sibling. Graft rejection occurred 6 months later. Allogeneic BM transplantation from the same donor (100% donor chimerism; FGFR1/8р11 translocation was not detected), which was complicated by the development of chronic graft-versus-host reaction, was performed again in March 2015. The patient is being followed up and continues to receive immunosuppressive therapy.

Use of PMA1 as a Housekeeping Biomarker for Assessment of Toxicant-Induced Stress in Saccharomyces cerevisiae

PubMed Central

Schmitt, Marcel; Schwanewilm, Petra; Ludwig, Jost; Lichtenberg-Fraté, Hella

2006-01-01

The brewer's yeast Saccharomyces cerevisiae has emerged as a versatile and robust model system for laboratory use to study toxic effects of various substances. In this study, toxicant-induced stresses of pure compounds were investigated in Saccharomyces cerevisiae utilizing a destabilized version of the green fluorescent protein optimized for expression in yeast (yEGFP3) under control of the promoter of the housekeeping plasma membrane ATPase gene PMA1. The responses of the biomarker upon increasing test compound concentrations were monitored by determining the decrease in fluorescence. The reporter assay deployed a simple and robust protocol for the rapid detection of toxic effects within a 96-well microplate format. Fluorescence emissions were normalized to cell growth determined by absorption and were correlated to internal reference standards. The results were expressed as effective concentrations (EC20). Dose-response experiments were conducted in which yeast cells were exposed in minimal medium and in the presence of 20% fetal calf serum to sublethal concentrations of an array of heavy metals, salt, and a number of stress-inducing compounds (Diclofenac, Lindane, methyl-N-nitro-N-nitrosoguanidine [MNNG], hydroxyurea, and caffeine). Long-term exposure (7 h) played a considerable role in the adaptive response to intoxication compared to early responses at 4 h exposure. The data obtained after 4 h of exposure and expressed as EC20 were compared to 50% inhibitory concentration values derived from cell line and ecotoxicological tests. This study demonstrates the versatility of the novel biomarker to complement existing test batteries to assess contaminant exposure and effects. PMID:16461706

Regulation of transcriptional silencing and chromodomain protein localization at centromeric heterochromatin by histone H3 tyrosine 41 phosphorylation in fission yeast.

PubMed

Ren, Bingbing; Tan, Hwei Ling; Nguyen, Thi Thuy Trang; Sayed, Ahmed Mahmoud Mohammed; Li, Ying; Mok, Yu-Keung; Yang, Henry; Chen, Ee Sin

2018-01-09

Heterochromatin silencing is critical for genomic integrity and cell survival. It is orchestrated by chromodomain (CD)-containing proteins that bind to methylated histone H3 lysine 9 (H3K9me), a hallmark of heterochromatin. Here, we show that phosphorylation of tyrosine 41 (H3Y41p)-a novel histone H3 modification-participates in the regulation of heterochromatin in fission yeast. We show that a loss-of-function mutant of H3Y41 can suppress heterochromatin de-silencing in the centromere and subtelomere repeat regions, suggesting a de-silencing role for H3Y41p on heterochromatin. Furthermore, we show both in vitro and in vivo that H3Y41p differentially regulates two CD-containing proteins without the change in the level of H3K9 methylation: it promotes the binding of Chp1 to histone H3 and the exclusion of Swi6. H3Y41p is preferentially enriched on centromeric heterochromatin during M- to early S phase, which coincides with the localization switch of Swi6/Chp1. The loss-of-function H3Y41 mutant could suppress the hypersensitivity of the RNAi mutants towards hydroxyurea (HU), which arrests replication in S phase. Overall, we describe H3Y41p as a novel histone modification that differentially regulates heterochromatin silencing in fission yeast via the binding of CD-containing proteins. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Correlation of low levels of nitrite and high levels of fetal hemoglobin in patients with sickle cell disease at baseline

PubMed Central

Elias, Darcielle Bruna Dias; Rocha, Lilianne Brito da Silva; Cavalcante, Maritza Barbosa; Pedrosa, Alano Martins; Justino, Izabel Cristina Bandeira; Gonçalves, Romélia Pinheiro

2012-01-01

Background Sickle cell disease is a hemoglobinopathy characterized by hemolytic anemia, increased susceptibility to infections and recurrent vaso-occlusive crises that reduces the quality of life of sufferers. Objective To evaluate the correlation of the levels of lactate dehydrogenase, malonaldehyde and nitrite to fetal hemoglobin in patients with sickle cell disease not under treatment with hydroxyurea in outpatients at a university hospital in Fortaleza, Ceará, Brazil. Methods Forty-four patients diagnosed with sickle cell disease were enrolled at baseline. Diagnosis was confirmed by evaluating the beta globin gene using polymerase chain reaction-restriction fragment length polymorphism. The concentration of fetal hemoglobin was obtained by high-performance liquid chromatography. Serum levels of nitrite, malonaldehyde and lactate dehydrogenase were measured by biochemical methods. Results Significantly higher levels of lactate dehydrogenase, nitrite and malonaldehyde were observed in patients with sickle cell disease compared to a control group. The study of the correlation between fetal hemoglobin levels and these variables showed a negative correlation with nitrite levels. No correlation was found between fetal hemoglobin and malonaldehyde or lactate dehydrogenase. When the study population was stratified according to fetal hemoglobin levels, a decrease in the levels of nitrite was observed with higher levels of fetal hemoglobin (p-value = 0.0415). Conclusion The results show that, similar to fetal hemoglobin levels, the concentration of nitrite can predict the clinical course of the disease, but should not be used alone as a modulator of prognosis in patients with sickle cell disease. PMID:23049438

Novel Connections Between DNA Replication, Telomere Homeostasis, and the DNA Damage Response Revealed by a Genome-Wide Screen for TEL1/ATM Interactions in Saccharomyces cerevisiae

PubMed Central

Piening, Brian D.; Huang, Dongqing; Paulovich, Amanda G.

2013-01-01

Tel1 is the budding yeast ortholog of the mammalian tumor suppressor and DNA damage response (DDR) kinase ATM. However, tel1-Δ cells, unlike ATM-deficient cells, do not exhibit sensitivity to DNA-damaging agents, but do display shortened (but stably maintained) telomere lengths. Neither the extent to which Tel1p functions in the DDR nor the mechanism by which Tel1 contributes to telomere metabolism is well understood. To address the first question, we present the results from a comprehensive genome-wide screen for genetic interactions with tel1-Δ that cause sensitivity to methyl methanesulfonate (MMS) and/or ionizing radiation, along with follow-up characterizations of the 13 interactions yielded by this screen. Surprisingly, many of the tel1-Δ interactions that confer DNA damage sensitivity also exacerbate the short telomere phenotype, suggesting a connection between these two phenomena. Restoration of normal telomere length in the tel1-Δ xxx-Δ mutants results in only minor suppression of the DNA damage sensitivity, demonstrating that the sensitivity of these mutants must also involve mechanisms independent of telomere length. In support of a model for increased replication stress in the tel1-Δ xxx-Δ mutants, we show that depletion of dNTP pools through pretreatment with hydroxyurea renders tel1-Δ cells (but not wild type) MMS-sensitive, demonstrating that, under certain conditions, Tel1p does indeed play a critical role in the DDR. PMID:23378069

Randomized trial comparing two methods of re-irradiation after salvage surgery in head and neck squamous cell carcinoma: Once daily split-course radiotherapy with concomitant chemotherapy or twice daily radiotherapy with cetuximab.

PubMed

Tao, Yungan; Faivre, Laura; Laprie, Anne; Boisselier, Pierre; Ferron, Christophe; Jung, Guy Michel; Racadot, Séverine; Gery, Bernard; Even, Caroline; Breuskin, Ingrid; Bourhis, Jean; Janot, François

2018-05-18

A previous randomized trial in recurrent Head and Neck squamous-cell carcinoma (HNSCC) has shown re-irradiation combined with chemotherapy after salvage surgery significantly improved disease-free survival (DFS). The objective of this randomized trial was to compare two methods of re-irradiation in terms of toxicity and survival. Patients with recurrence/second primary in previously irradiated area were randomly allocated to receive either 60 Gy over 11 weeks with concomitant 5FU - hydroxyurea (VP-arm), or 60 Gy (1.2 Gy twice daily) over 5 weeks with cetuximab (HFR-arm). Primary endpoint was treatment interruption >15 days (acute toxicity). Twenty-six patients were included in VP-arm and 27 in HFR-arm. One patient in VP-arm experienced >15 days interruption due to toxicity, and none in HFR-arm. In both arms, all patients received at least 60 Gy. In VP-arm, 8/26 patients had chemotherapy delay and/or dose reduction. In HFR-arm, 4/27 patients had <6 cycles cetuximab. There was no significant difference in overall survival (Median OS: 37.4 months vs 21.9 months, p = 0.12). Toxicities and DFS were not different between 2 arms. Twice daily schedule of re-irradiation of 60 Gy/5 weeks with cetuximab was tolerable and no significant difference in treatment delays occurred between two arms. Copyright © 2018 Elsevier B.V. All rights reserved.

DNA Damage Response Resulting from Replication Stress Induced by Synchronization of Cells by Inhibitors of DNA Replication: Analysis by Flow Cytometry.

PubMed

Halicka, Dorota; Zhao, Hong; Li, Jiangwei; Garcia, Jorge; Podhorecka, Monika; Darzynkiewicz, Zbigniew

2017-01-01

Cell synchronization is often achieved by transient inhibition of DNA replication. When cultured in the presence of such inhibitors as hydroxyurea, aphidicolin or excess of thymidine the cells that become arrested at the entrance to S-phase upon release from the block initiate progression through S then G 2 and M. However, exposure to these inhibitors at concentrations commonly used to synchronize cells leads to activation of ATR and ATM protein kinases as well as phosphorylation of Ser139 of histone H2AX. This observation of DNA damage signaling implies that synchronization of cells by these inhibitors is inducing replication stress. Thus, a caution should be exercised while interpreting data obtained with use of cells synchronized this way since they do not represent unperturbed cell populations in a natural metabolic state. This chapter critically outlines virtues and vices of most cell synchronization methods. It also presents the protocol describing an assessment of phosphorylation of Ser139 on H2AX and activation of ATM in cells treated with aphidicolin, as a demonstrative of one of several DNA replication inhibitors that are being used for cell synchronization. Phosphorylation of Ser139H2AX and Ser1981ATM in individual cells is detected immunocytochemically with phospho-specific Abs and intensity of immunofluorescence is measured by flow cytometry. Concurrent measurement of cellular DNA content followed by multiparameter analysis allows one to correlate the extent of phosphorylation of these proteins in response to aphidicolin with the cell cycle phase.

Resistance of uveal melanoma to the interstrand cross-linking agent mitomycin C is associated with reduced expression of CYP450R

PubMed Central

Gravells, P; Hoh, L; Canovas, D; Rennie, I G; Sisley, K; Bryant, H E

2011-01-01

Background: Uveal melanoma (UM) is the most common primary intraocular tumour of adults, frequently metastasising to the liver. Hepatic metastases are difficult to treat and are mainly unresponsive to chemotherapy. To investigate why UM are so chemo-resistant we explored the effect of interstrand cross-linking agents mitomycin C (MMC) and cisplatin in comparison with hydroxyurea (HU). Methods: Sensitivity to MMC, cisplatin and HU was tested in established UM cell lines using clonogenic assays. The response of UM to MMC was confirmed in MTT assays using short-term cultures of primary UM. The expression of cytochrome P450 reductase (CYP450R) was analysed by western blotting, and DNA cross-linking was assessed using COMET analysis supported by γ-H2AX foci formation. Results: Both established cell lines and primary cultures of UM were resistant to the cross-linking agent MMC (in each case P<0.001 in Student's t-test compared with controls). In two established UM cell lines, DNA cross-link damage was not induced by MMC (in both cases P<0.05 in Students's t-test compared with damage induced in controls). In all, 6 out of 6 UMs tested displayed reduced expression of the metabolising enzyme CYP450R and transient expression of CYP450R increased MMC sensitivity of UM. Conclusion: We suggest that reduced expression of CYP450R is responsible for MMC resistance of UM, through a lack of bioactivation, which can be reversed by complementing UM cell lines with CYP450R. PMID:21386838

The plant homeodomain fingers of fission yeast Msc1 exhibit E3 ubiquitin ligase activity.

PubMed

Dul, Barbara E; Walworth, Nancy C

2007-06-22

The DNA damage checkpoint pathway governs how cells regulate cell cycle progression in response to DNA damage. A screen for suppressors of a fission yeast chk1 mutant defective in the checkpoint pathway identified a novel Schizosaccharomyces pombe protein, Msc1. Msc1 contains 3 plant homeodomain (PHD) finger motifs, characteristically defined by a C4HC3 consensus similar to RING finger domains. PHD finger domains in viral proteins and in the cellular protein kinase MEKK1 (mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase 1) have been implicated as ubiquitin E3 protein ligases that affect protein stability. The close structural relationship of PHD fingers to RING fingers suggests that other PHD domain-containing proteins might share this activity. We show that each of the three PHD fingers of Msc1 can act as ubiquitin E3 ligases, reporting for the first time that PHD fingers from a nuclear protein exhibit E3 ubiquitin ligase activity. The function of the PHD fingers of Msc1 is needed to rescue the DNA damage sensitivity of a chk1Delta strain. Msc1 co-precipitates Rhp6, the S. pombe homologue of the human ubiquitin-conjugating enzyme Ubc2. Strikingly, deletion of msc1 confers complete suppression of the slow growth phenotype, UV and hydroxyurea sensitivities of an rhp6 deletion strain and restores deficient histone H3 methylation observed in the rhp6Delta mutant. We speculate that the target of the E3 ubiquitin ligase activity of Msc1 is likely to be a chromatin-associated protein.

The Smc5/Smc6/MAGE Complex Confers Resistance to Caffeine and Genotoxic Stress in Drosophila melanogaster

PubMed Central

Li, Xiao; Zhuo, Ran; Tiong, Stanley; Di Cara, Francesca; King-Jones, Kirst; Hughes, Sarah C.; Campbell, Shelagh D.; Wevrick, Rachel

2013-01-01

The SMC5/6 protein complex consists of the Smc5, Smc6 and Non-Smc-Element (Nse) proteins and is important for genome stability in many species. To identify novel components in the DNA repair pathway, we carried out a genetic screen to identify mutations that confer reduced resistance to the genotoxic effects of caffeine, which inhibits the ATM and ATR DNA damage response proteins. This approach identified inactivating mutations in CG5524 and MAGE, homologs of genes encoding Smc6 and Nse3 in yeasts. The fact that Smc5 mutants are also caffeine-sensitive and that Mage physically interacts with Drosophila homologs of Nse proteins suggests that the structure of the Smc5/6 complex is conserved in Drosophila. Although Smc5/6 proteins are required for viability in S. cerevisiae, they are not essential under normal circumstances in Drosophila. However, flies carrying mutations in Smc5, Smc6 and MAGE are hypersensitive to genotoxic agents such as ionizing radiation, camptothecin, hydroxyurea and MMS, consistent with the Smc5/6 complex serving a conserved role in genome stability. We also show that mutant flies are not compromised for pre-mitotic cell cycle checkpoint responses. Rather, caffeine-induced apoptosis in these mutants is exacerbated by inhibition of ATM or ATR checkpoint kinases but suppressed by Rad51 depletion, suggesting a functional interaction involving homologous DNA repair pathways that deserves further scrutiny. Our insights into the SMC5/6 complex provide new challenges for understanding the role of this enigmatic chromatin factor in multi-cellular organisms. PMID:23555814

VDE-initiated intein homing in Saccharomyces cerevisiae proceeds in a meiotic recombination-like manner.

PubMed

Fukuda, Tomoyuki; Nogami, Satoru; Ohya, Yoshikazu

2003-07-01

Inteins and group I introns found in prokaryotic and eukaryotic organisms occasionally behave as mobile genetic elements. During meiosis of the yeast Saccharomyces cerevisiae, the site-specific endonuclease encoded by VMA1 intein, VDE, triggers a single double-strand break (DSB) at an inteinless allele, leading to VMA1 intein homing. Besides the accumulating information on the in vitro activity of VDE, very little has been known about the molecular mechanism of intein homing in yeast nucleus. We developed an assay to detect the product of VMA1 intein homing in yeast genome. We analysed mutant phenotypes of RecA homologs, Rad51p and Dmc1p, and their interacting proteins, Rad54p and Tid1p, and found that they all play critical roles in intein inheritance. The absence of DSB end processing proteins, Sae2p and those in the Mre11-Rad50-Xrs2 complex, also causes partial reduction in homing efficiency. As with meiotic recombination, crossover events are frequently observed during intein homing. We also observed that the absence of premeiotic DNA replication caused by hydroxyurea (HU) or clb5delta clb6delta mutation reduces VDE-mediated DSBs. The repairing system working in intein homing shares molecular machinery with meiotic recombination induced by Spo11p. Moreover, like Spo11p-induced DNA cleavage, premeiotic DNA replication is a prerequisite for a VDE-induced DSB. VMA1 intein thus utilizes several host factors involved in meiotic and recombinational processes to spread its genetic information and guarantee its progeny through establishment of a parasitic relationship with the organism.

Insights into mutagenesis using Escherichia coli chromosomal lacZ strains that enable detection of a wide spectrum of mutational events.

PubMed

Seier, Tracey; Padgett, Dana R; Zilberberg, Gal; Sutera, Vincent A; Toha, Noor; Lovett, Susan T

2011-06-01

Strand misalignments at DNA repeats during replication are implicated in mutational hotspots. To study these events, we have generated strains carrying mutations in the Escherichia coli chromosomal lacZ gene that revert via deletion of a short duplicated sequence or by template switching within imperfect inverted repeat (quasipalindrome, QP) sequences. Using these strains, we demonstrate that mutation of the distal repeat of a quasipalindrome, with respect to replication fork movement, is about 10-fold higher than the proximal repeat, consistent with more common template switching on the leading strand. The leading strand bias was lost in the absence of exonucleases I and VII, suggesting that it results from more efficient suppression of template switching by 3' exonucleases targeted to the lagging strand. The loss of 3' exonucleases has no effect on strand misalignment at direct repeats to produce deletion. To compare these events to other mutations, we have reengineered reporters (designed by Cupples and Miller 1989) that detect specific base substitutions or frameshifts in lacZ with the reverting lacZ locus on the chromosome rather than an F' element. This set allows rapid screening of potential mutagens, environmental conditions, or genetic loci for effects on a broad set of mutational events. We found that hydroxyurea (HU), which depletes dNTP pools, slightly elevated templated mutations at inverted repeats but had no effect on deletions, simple frameshifts, or base substitutions. Mutations in nucleotide diphosphate kinase, ndk, significantly elevated simple mutations but had little effect on the templated class. Zebularine, a cytosine analog, elevated all classes.

Rare but Lethal Hepatopathy-Sickle Cell Intrahepatic Cholestasis and Management Strategies.

PubMed

Malik, Aamir; Merchant, Chandni; Rao, Mana; Fiore, Rosemary P

2015-11-28

Sickle cell disease can affect the liver by way of the disease process, including sickling in hepatic sinusoids, as well as its treatment, including repeated blood transfusions leading to hemosiderosis and hepatitis. Sickle cell intrahepatic cholestasis (SCIC) is an extreme variant of sickle cell hepatopathy, and is associated with high fatality. We present the case of a 31-year-old man with past medical history of sickle cell disease and cholecystectomy who was admitted with uncomplicated vaso occlusive crisis and during the hospital stay developed fever, upper abdominal pain, and jaundice. There was an accelerated rise in total bilirubin to 50 mg/dL, direct bilirubin 38 mg/dL, and Cr 3.0 mg/dL. Hb was 6.4 g/dL, reticulocyte count 16%, ALT 40 IU/L, AST 155 IU/L, ALP 320 IU/L, and LDH 475 IU/L. Hepatitis panel was negative and MRCP showed normal caliber of the common bile duct, with no obstruction. Exchange transfusion of 9 units of packed red blood cells led to great improvement in his condition. SCIC, unlike the other sickle cell hepatopathies, requires urgent and vigorous exchange transfusion. Renal impairment in SCIC has not been well studied but usually is reversible with the hepatic impairment, as in this case. Unresolved renal impairment requires dialysis and is associated with poor outcome. There is limited data on use of hydroxyurea to prevent SCIC, and liver transplant is associated with high mortality. A timely diagnosis of SCIC and appropriate management is life-saving.

Systemic mastocytosis in adults: 2013 update on diagnosis, risk stratification, and management.

PubMed

Pardanani, Animesh

2013-07-01

Systemic mastocytosis (SM) results from a clonal proliferation of abnormal mast cells (MC) in one or more extracutaneous organs. The major criterion is presence of multifocal clusters of morphologically abnormal MC in the bone marrow. Minor diagnostic criteria include elevated serum tryptase level, abnormal MC expression of CD25 and/or CD2, and presence of KITD816V. The 2008 World Health Organization (WHO) classification of SM has been shown to be prognostically relevant. Classification of SM patients into indolent (SM), aggressive SM (ASM), SM associated with a clonal non-MC lineage disease (SM-AHNMD) and mast cell leukemia (MCL) subgroups is a useful first step in establishing prognosis. SM treatment is generally palliative. ISM patients have a normal life expectancy and receive symptom-directed therapy; infrequently, cytoreductive therapy may be indicated for refractory symptoms. ASM patients have disease-related organ dysfunction; interferon-α (±corticosteroids) can control dermatological, hematological, gastrointestinal, skeletal, and mediator-release symptoms, but is hampered by poor tolerability. Similarly, cladribine has broad therapeutic activity, with particular utility when rapid MC debulking is indicated; the main toxicity is myelosuppression. Imatinib has a therapeutic role in the presence of an imatinib-sensitive KIT mutation or in KITD816-unmutated patients. Treatment of SM-AHNMD is governed primarily by the non-MC neoplasm; hydroxyurea has modest utility in this setting. Dasatinib's in vitro anti- KITD816V activity has not translated into significant therapeutic activity in most SM patients. In contrast, recently updated data confirms Midostaurin's significant anti-MC activity in patients with advanced SM. Copyright © 2013 Wiley Periodicals, Inc.

Systemic mastocytosis in adults: 2012 Update on diagnosis, risk stratification, and management.

PubMed

Pardanani, Animesh

2012-04-01

Systemic mastocytosis (SM) results from a clonal proliferation of abnormal mast cells (MC) in one or more extra-cutaneous organs. The major criterion is presence of multifocal clusters of morphologically abnormal MC in the bone marrow. Minor diagnostic criteria include elevated serum tryptase level, abnormal MC expression of CD25 and/or CD2, and presence of KITD816V. The prognostic relevance of the 2008 World Health Organization (WHO) classification of SM has recently been confirmed. Classification of SM patients into indolent (SM), aggressive SM (ASM), SM associated with a clonal non-MC lineage disease (SM-AHNMD) and mast cell leukemia (MCL) subgroups is a useful first step in establishing prognosis. SM treatment is generally palliative. ISM patients have a normal life expectancy and receive symptom-directed therapy; infrequently, cytoreductive therapy may be indicated for refractory symptoms. ASM patients have disease-related organ dysfunction; interferon-α (±corticosteroids) can control dermatological, hematological, gastrointestinal, skeletal, and mediator-release symptoms, but is hampered by poor tolerability. Similarly, cladribine has broad therapeutic activity, with particular utility when rapid MC debulking is indicated; the main toxicity is myelosuppression. Imatinib has a therapeutic role in the presence of an imatinib-sensitive KIT mutation or in KITD816-unmutated patients. Treatment of SM-AHNMD is governed primarily by the non-MC neoplasm; hydroxyurea has modest utility in this setting. Dasatinib's in vitro anti-KITD816V activity has not translated into significant therapeutic activity in most SM patients. In contrast, preliminary data suggest that Midostaurin may produce significant decreases in MC burden in some patients. Copyright © 2012 Wiley Periodicals, Inc.

Systemic mastocytosis in adults: 2015 update on diagnosis, risk stratification, and management.

PubMed

Pardanani, Animesh

2015-03-01

Systemic mastocytosis (SM) results from a clonal proliferation of abnormal mast cells (MC) in one or more extracutaneous organs. The major criterion is presence of multifocal clusters of morphologically abnormal MC in the bone marrow. Minor diagnostic criteria include elevated serum tryptase level, abnormal MC expression of CD25 and/or CD2, and presence of KITD816V. The 2008 World Health Organization classification of SM has been shown to be prognostically relevant. Classification of SM patients into indolent SM (ISM), aggressive SM (ASM), SM associated with a clonal non-MC lineage disease (SM-AHNMD), and mast cell leukemia (MCL) subgroups is a useful first step in establishing prognosis. SM treatment is generally palliative. ISM patients have a normal life expectancy and receive symptom-directed therapy; infrequently, cytoreductive therapy may be indicated for refractory symptoms. ASM patients have disease-related organ dysfunction; interferon-α (+/-corticosteroids) can control dermatological, hematological, gastrointestinal, skeletal, and mediator-release symptoms, but is hampered by poor tolerability. Similarly, cladribine has broad therapeutic activity, with particular utility when rapid MC debulking is indicated; the main toxicity is myelosuppression. Imatinib has a therapeutic role in the presence of an imatinib-sensitive KIT mutation or in KITD816-unmutated patients. Treatment of SM-AHNMD is governed primarily by the non-MC neoplasm; hydroxyurea has modest utility in this setting; there is a role for allogeneic stem cell transplantation in select cases. Investigational Drugs: Recent data confirms midostaurin's significant anti-MC activity in patients with advanced SM. © 2015 Wiley Periodicals, Inc.

Systemic mastocytosis in adults: 2011 update on diagnosis, risk stratification, and management.

PubMed

Pardanani, Animesh

2011-04-01

Systemic mastocytosis (SM) results from a clonal proliferation of abnormal mast cells (MC) in one or more extracutaneous organs. The major criterion is presence of multifocal clusters of morphologically abnormal MC in the bone marrow. Minor diagnostic criteria include elevated serum tryptase level, abnormal MC expression of CD25 and/or CD2, and presence of KITD816V. The prognostic relevance of the 2008 World Health Organization (WHO) classification of SM has recently been confirmed. Classification of SM patients into indolent (SM), aggressive SM (ASM), SM associated with a clonal non-MC lineage disease (SM-AHNMD), and mast cell leukemia (MCL) subgroups is a useful first step in establishing prognosis. SM treatment is generally palliative. ISM patients have a normal life expectancy and receive symptom-directed therapy; infrequently, cytoreductive therapy may be indicated for refractory symptoms. ASM patients have disease-related organ dysfunction; interferon-α (±corticosteroids) can control dermatological, hematological, gastrointestinal, skeletal, and mediator-release symptoms, but is hampered by poor tolerability. Similarly, cladribine has broad therapeutic activity, with particular utility when rapid MC debulking is indicated; the main toxicity is myelosuppression. Imatinib has a therapeutic role in the presence of an imatinib-sensitive KIT mutation or in KITD816-unmutated patients. Treatment of SM-AHNMD is governed primarily by the non-MC neoplasm; hydroxyurea has modest utility in this setting. Dasatinib's in vitro anti- KITD816V activity has not translated into significant therapeutic activity in most SM patients. In contrast, preliminary data suggest that Midostaurin may produce significant decreases in MC burden in some patients. Copyright © 2011 Wiley-Liss, Inc.

Lamin A/C Depletion Enhances DNA Damage-Induced Stalled Replication Fork Arrest

PubMed Central

Singh, Mayank; Hunt, Clayton R.; Pandita, Raj K.; Kumar, Rakesh; Yang, Chin-Rang; Horikoshi, Nobuo; Bachoo, Robert; Serag, Sara; Story, Michael D.; Shay, Jerry W.; Powell, Simon N.; Gupta, Arun; Jeffery, Jessie; Pandita, Shruti; Chen, Benjamin P. C.; Deckbar, Dorothee; Löbrich, Markus; Yang, Qin; Khanna, Kum Kum; Worman, Howard J.

2013-01-01

The human LMNA gene encodes the essential nuclear envelope proteins lamin A and C (lamin A/C). Mutations in LMNA result in altered nuclear morphology, but how this impacts the mechanisms that maintain genomic stability is unclear. Here, we report that lamin A/C-deficient cells have a normal response to ionizing radiation but are sensitive to agents that cause interstrand cross-links (ICLs) or replication stress. In response to treatment with ICL agents (cisplatin, camptothecin, and mitomycin), lamin A/C-deficient cells displayed normal γ-H2AX focus formation but a higher frequency of cells with delayed γ-H2AX removal, decreased recruitment of the FANCD2 repair factor, and a higher frequency of chromosome aberrations. Similarly, following hydroxyurea-induced replication stress, lamin A/C-deficient cells had an increased frequency of cells with delayed disappearance of γ-H2AX foci and defective repair factor recruitment (Mre11, CtIP, Rad51, RPA, and FANCD2). Replicative stress also resulted in a higher frequency of chromosomal aberrations as well as defective replication restart. Taken together, the data can be interpreted to suggest that lamin A/C has a role in the restart of stalled replication forks, a prerequisite for initiation of DNA damage repair by the homologous recombination pathway, which is intact in lamin A/C-deficient cells. We propose that lamin A/C is required for maintaining genomic stability following replication fork stalling, induced by either ICL damage or replicative stress, in order to facilitate fork regression prior to DNA damage repair. PMID:23319047

Quality of life of chronic myeloid leukemia patients in Brazil: ability to work as a key factor.

PubMed

Hamerschlak, Nelson; de Souza, Carmino; Cornacchioni, Ana Lúcia; Pasquini, Ricardo; Tabak, Daniel; Spector, Nelson; Steagall, Merula

2014-08-01

The purpose of this study was to evaluate the quality of life (QOL) of patients receiving treatment by the public health system in Brazil for chronic myeloid leukemia (CML), a disease requiring daily and strict compliance to oral medication and regular blood and bone marrow controls, which are invasive exams. Between 2008 and 2010, patients with CML were surveyed by telephone. Quality of life was evaluated by the functional assessment of chronic illness therapy (FACIT) tool. The mean QOL among CML patients was 92.53 (out of 124 total points) in the trial outcome index, 78.50 (out of 108) in the general total score, and 130.43 (out of 176) in the leukemia total score. Patients who had the prescriptions recently changed anyway had better QOL general score (p = 0.012) and leukemia-specific score (p = 0.043) than those who remained with the same treatment. Imatinib was not associated with this change in QOL (p > 0.797). The more the patient felt able to work, the higher the scores in all three FACIT scales (p < 0.001, Spearman's correlation). The use of imatinib (p = 0.012) was associated with a better ability to work, while chemotherapy (p = 0.017) and the use of hydroxyurea (p = 0.001) were inversely associated with work capability. A recent change in medication can improve quality of life. The ability to work is an important component of quality of life of patients with CML. Ability to work should be specifically considered in CML treatment.

A compromised yeast RNA polymerase II enhances UV sensitivity in the absence of global genome nucleotide excision repair.

PubMed

Wong, J M; Ingles, C J

2001-02-01

Nucleotide excision repair is the major pathway responsible for removing UV-induced DNA damage, and is therefore essential for cell survival following exposure to UV radiation. In this report, we have assessed the contributions of some components of the RNA polymerase II (Pol II) transcription machinery to UV resistance in Saccharomyces cerevisiae. Deletion of the gene encoding the Pol II elongation factor TFIIS (SII) resulted in enhanced UV sensitivity, but only in the absence of global genome repair dependent on the RAD7 and RAD16 genes, a result seen previously with deletions of RAD26 and RAD28, yeast homologs of the human Cockayne syndrome genes CSB and CSA, respectively. A RAD7/16-dependent reduction in survival after UV irradiation was also seen in the presence of mutations in RNA Pol II that confer a defect in its response to SII, as well as with other mutations which reside in regions of the largest subunit of Pol II not involved in SII interactions. Indeed, an increase in UV sensitivity was achieved by simply decreasing the steadystate level of RNA Pol II. Truncation of the C-terminal domain and other RNA Pol II mutations conferred sensitivity to the ribonucleotide reductase inhibitor hydroxyurea and induction of RNR1 and RNR2 mRNAs after UV irradiation was attenuated in these mutant cells. That UV sensitivity can be a consequence of mutations in the RNA Pol II machinery in yeast cells suggests that alterations in transcriptional programs could underlie some of the pathophysiological defects seen in the human disease Cockayne syndrome.

UV-B inhibition of hypocotyl growth in etiolated Arabidopsis thaliana seedlings is a consequence of cell cycle arrest initiated by photodimer accumulation

PubMed Central

Biever, Jessica J.; Brinkman, Doug; Gardner, Gary

2014-01-01

Ultraviolet (UV) radiation is an important constituent of sunlight that determines plant morphology and growth. It induces photomorphogenic responses but also causes damage to DNA. Arabidopsis mutants of the endonucleases that function in nucleotide excision repair, xpf-3 and uvr1-1, showed hypersensitivity to UV-B (280–320nm) in terms of inhibition of hypocotyl growth. SOG1 is a transcription factor that functions in the DNA damage signalling response after γ-irradiation. xpf mutants that carry the sog1-1 mutation showed hypocotyl growth inhibition after UV-B irradiation similar to the wild type. A DNA replication inhibitor, hydroxyurea (HU), also inhibited hypocotyl growth in etiolated seedlings, but xpf-3 was not hypersensitive to HU. UV-B irradiation induced accumulation of the G2/M-specific cell cycle reporter construct CYCB1;1-GUS in wild-type Arabidopsis seedlings that was consistent with the expected accumulation of photodimers and coincided with the time course of hypocotyl growth inhibition after UV-B treatment. Etiolated mutants of UVR8, a recently described UV-B photoreceptor gene, irradiated with UV-B showed inhibition of hypocotyl growth that was not different from that of the wild type, but they lacked UV-B-specific expression of chalcone synthase (CHS), as expected from previous reports. CHS expression after UV-B irradiation was not different in xpf-3 compared with the wild type, nor was it altered after HU treatment. These results suggest that hypocotyl growth inhibition by UV-B light in etiolated Arabidopsis seedlings, a photomorphogenic response, is dictated by signals originating from UV-B absorption by DNA that lead to cell cycle arrest. This process occurs distinct from UVR8 and its signalling pathway responsible for CHS induction. PMID:24591052

Optimal Outcomes in Young Class 3 Patients With Thalassemia Undergoing HLA-Identical Sibling Bone Marrow Transplantation.

PubMed

Gaziev, Javid; Isgrò, Antonella; Sodani, Pietro; Marziali, Marco; Paciaroni, Katia; Gallucci, Cristiano; De Angelis, Gioia; Andreani, Marco; Testi, Manuela; Alfieri, Cecilia; Ribersani, Michela; Galluccio, Tiziana; Battarra, Maria Rosa; Morrone, Aldo; Lucarelli, Guido

2016-04-01

Bone marrow transplantation (BMT) for class 3 patients with thalassemia is challenging due to high rates of graft rejection and transplant-related mortality. Since the first studies of BMT in the late 1980s, a number of conditioning regimens have been designed to improve outcomes, but with suboptimal results. Here we report the outcome of transplantation in class 3 patients using a modified protocol. Sixty-three patients between 5 and 16.7 years of age with class 3 thalassemia received HLA-matched sibling BMT following either the original protocol (26 patients) or the modified protocol (37 patients). Both regimens comprised preconditioning cytoreduction with hydroxyurea and azathioprine starting at -45 days pretransplant, and fludarabine from days -16 to -12. Conditioning was performed with busulfan and cyclophosphamide (original protocol) or with busulfan, thiotepa, and cyclophosphamide (modified protocol). The 2 groups showed similar patient demographics. At day 0, the degree of cytoreduction (lymphopenia, neuthropenia, and thrombocytopenia) achieved by the modified protocol was greater than the original protocol. The incidence of graft failure/rejection was significantly higher in the original group (15%; 95% confidence interval [95% CI], 5-32%) compared with the modified group (0%) (P = 0.014). The respective 5-year thalassemia-free survival rates were 73% (95% CI, 51-86%) and 92% (95% CI, 77-97%) (P = 0.047). Both groups showed similar incidences of grades II to IV acute graft-versus host disease. Modified protocol did not increase nonhematological toxicity or infectious complications. The modified treatment protocol effectively and safely prevented graft failure/rejection and significantly increased thalassemia-free survival of class 3 patients with thalassemia.

Increased erythrocyte deformability in fetal erythropoiesis and in erythrocytes deficient in glucose-6-phosphate dehydrogenase and other glycolytic enzymes.

PubMed

Johnson, R M; Panchoosingh, H; Goyette, G; Ravindranath, Y

1999-01-01

Erythrocyte deformability was determined in more than 500 clinical samples, and was found to be elevated in conditions in which fetal-like red cells are produced: aplastic anemia (3/3 cases), myelodysplastic syndromes, polycythemias, sickle cell anemia during treatment with hydroxyurea, paroxysmal nocturnal hemoglobinuria, and recovery from B12 deficiency. Elevated deformability was observed in neonatal erythrocytes, and during recovery from transient erythroblastopenia of childhood, when fetal-like red cells are known to be produced. Increased deformability appears to be a feature of fetal and fetal-like red cells. Forty-eight cases of enzymatically verified glucose-6-phosphate (G-6-PD) deficiency were also examined. Thirty out of 32 G-6-PD(A-) individuals, including both heterozygotes and hemizygotes, exhibited increased deformability during the steady state. In contrast, G-6-PD(Med) hemizygotes had normal deformability. Increased deformability was also found in G-6-PD(Huron) (n=3), G-6-PD(Wayne) (n=4), triose phosphate isomerase deficiency (n=2), and pyruvate kinase deficiency (n=2). An elevated osmoscan was found in more than 90% of female G-6-PD heterozygotes, affording a simple screening test for heterozygotes. Deformability remained high during hemolytic episodes, when older enzyme deficient cells are removed from the circulation. In four cases of G-6-PD deficiency with normal deformability, evidence for co-existing hereditary spherocytosis was found. The combination of conditions with opposing effects on deformability resulted in nearly normal deformability. Because increased red cell deformability is a feature of fetal erythrocytes, these results suggest that the red cells in many cases of glycolytic enzyme deficiency are fetal-like.

Challenge of managing sickle cell disease in a pediatric population living in kinshasa, democratic republic of congo: a sickle cell center experience.

PubMed

Aloni, Michel Ntetani; Nkee, Leonard

2014-01-01

In the Democratic Republic of Congo (DRC), sickle cell disease is not yet really regarded as a health care priority. The patterns of sickle cell disease in patients living in Kinshasa, DRC are discussed and the difficulties encountered in their management are highlighted. The cross-sectional survey is of sickle cell patients and their families attending the Centre de Médecine Mixte et d'Anémie SS de Yolo (CMMASS), Kinshasa, DRC, between January and April 2009. Completed questionnaires were received from 168 respondents (111 girls; 57 boys). Seventy-one percent of the subjects were diagnosed before the age of 2 years but none in the neonatal period. Sickle cell disease was diagnosed in 54.8% of the patients after they had suffered pain crises. Of the 168 subjects, 74.0% had previously received blood transfusions. Seventy-five (45.0%) had more than three severe pain crises per year. A minority of 35.0% reported that they regularly took an antibioprophylaxis. Seventy-five (45.0%) subjects were eligible for hydroxyurea (HU) therapy but in all cases this drug was taken irregularly. Eighty-two percent of drugs were purchased by the parents. One hundred and sixty-three children (97.0%) were vaccinated according to the Expanded Programme on Immunization (EPI), 61.0% against Streptococcus pneumoniae and 16.0% against the Hepatitis B virus (HBV). No case of immunization against Hemophilus influenzae and Salmonella sp was reported. Neonatal screening programs, early educational detection programs for families, use of current method treatments and an implementation of a health insurance system for sickle cell disease will improve detection and management for these and future patients in our population.

Acute Crises and Complications of Sickle Cell Anemia Among Patients Attending a Pediatric Tertiary Unit in Kinshasa, Democratic Republic Of Congo.

PubMed

Aloni, Michel Ntetani; Kadima, Bertin Tshimanga; Ekulu, Pépé Mfutu; Budiongo, Aléine Nzazi; Ngiyulu, René Makuala; Gini-Ehungu, Jean Lambert

2017-06-01

In the Democratic Republic of Congo, the incidence of sickle cell anemia (SCA) is estimated to affect 30,000 to 40,000 neonates per year. However, there is paucity of data on acute clinical manifestations in sickle cell children. In these circumstances, it is difficult to develop a health care policy for an adequate management of sickle cell patients. This was a seven years' retrospective study of children admitted with acute sickle cell crisis in the Department of Pediatrics in University Hospital of Kinshasa, Kinshasa, the Democratic Republic of Congo. A total of 108 patients were identified as having SCA. There were 56 (51%) girls and 52 (49%) boys. Median age was 10.5 years (range 1-24 years). No child was diagnosed by neonatal screening. The median age of diagnosis of sickle cell anemia was 90 months (range: 8-250 months). The median age at the first transfusion was 36 months (range 4-168). In this series, 61 (56.5%) patients were eligible for hydroxyurea. However, this treatment was only performed in 4 (6.6%) of them. Pain episodes, acute anemic crisis and severe infection represent respectively 38.2%, 34.3% and 21.9% of events. Altered sensorium and focal deficit were encountered occasionally and represented 3.4% of acute events. Acute renal manifestations, cholelithiasis and priapism were rarely reported, in this cohort. In Kinshasa, the care of patients suffering from sickle cell anemia is characterized by the delayed diagnosis and low detection of organ complications compared to reports of Western countries. This situation is due to resources deficiencies.

Repriming by PrimPol is critical for DNA replication restart downstream of lesions and chain-terminating nucleosides.

PubMed

Kobayashi, Kaori; Guilliam, Thomas A; Tsuda, Masataka; Yamamoto, Junpei; Bailey, Laura J; Iwai, Shigenori; Takeda, Shunichi; Doherty, Aidan J; Hirota, Kouji

2016-08-02

PrimPol is a DNA damage tolerance enzyme possessing both translesion synthesis (TLS) and primase activities. To uncover its potential role in TLS-mediated IgVλ hypermutation and define its interplay with other TLS polymerases, PrimPol(-/-) and PrimPol(-/-)/Polη(-/-)/Polζ (-/-) gene knockouts were generated in avian cells. Loss of PrimPol had no significant impact on the rate of hypermutation or the mutation spectrum of IgVλ. However, PrimPol(-/-) cells were sensitive to methylmethane sulfonate, suggesting that it may bypass abasic sites at the IgVλ segment by repriming DNA synthesis downstream of these sites. PrimPol(-/-) cells were also sensitive to cisplatin and hydroxyurea, indicating that it assists in maintaining / restarting replication at a variety of lesions. To accurately measure the relative contribution of the TLS and primase activities, we examined DNA damage sensitivity in PrimPol(-/-) cells complemented with polymerase or primase-deficient PrimPol. Polymerase-defective, but not primase-deficient, PrimPol suppresses the hypersensitivity of PrimPol(-/-) cells. This indicates that its primase, rather than TLS activity, is pivotal for DNA damage tolerance. Loss of TLS polymerases, Polη and Polζ has an additive effect on the sensitivity of PrimPol(-/-) cells. Moreover, we found that PrimPol and Polη-Polζ redundantly prevented cell death and facilitated unperturbed cell cycle progression. PrimPol(-/-) cells also exhibited increased sensitivity to a wide variety of chain-terminating nucleoside analogs (CTNAs). PrimPol could perform close-coupled repriming downstream of CTNAs and oxidative damage in vitro. Together, these results indicate that PrimPol's repriming activity plays a central role in reinitiating replication downstream from CTNAs and other specific DNA lesions.

Translating sickle cell guidelines into practice for primary care providers with Project ECHO

PubMed Central

Shook, Lisa M.; Farrell, Christina B.; Kalinyak, Karen A.; Nelson, Stephen C.; Hardesty, Brandon M.; Rampersad, Angeli G.; Saving, Kay L.; Whitten-Shurney, Wanda J.; Panepinto, Julie A.; Ware, Russell E.; Crosby, Lori E.

2016-01-01

Background Approximately 100,000 persons with sickle cell disease (SCD) live in the United States, including 15,000 in the Midwest. Unfortunately, many patients experience poor health outcomes due to limited access to primary care providers (PCPs) who are prepared to deliver evidence-based SCD care. Sickle Treatment and Outcomes Research in the Midwest (STORM) is a regional network established to improve care and outcomes for individuals with SCD living in Indiana, Illinois, Michigan, Minnesota, Ohio, and Wisconsin. Methods STORM investigators hypothesized that Project ECHO® methodology could be replicated to create a low-cost, high-impact intervention to train PCPs in evidence-based care for pediatric and young adult patients with SCD in the Midwest, called STORM TeleECHO. This approach utilizes video technology for monthly telementoring clinics consisting of didactic and case-based presentations focused on the National Heart, Lung and Blood Institute (NHLBI) evidence-based guidelines for SCD. Results Network leads in each of the STORM states assisted with developing the curriculum and are recruiting providers for monthly clinics. To assess STORM TeleECHO feasibility and acceptability, monthly attendance and satisfaction data are collected. Changes in self-reported knowledge, comfort, and practice patterns will be compared with pre-participation, and 6 and 12 months after participation. Conclusions STORM TeleECHO has the potential to increase implementation of the NHLBI evidence-based guidelines, especially increased use of hydroxyurea, resulting in improvements in the quality of care and outcomes for children and young adults with SCD. This model could be replicated in other pediatric chronic illness conditions to improve PCP knowledge and confidence in delivering evidence-based care. PMID:27887664

Can pegylated interferon improve the outcome of polycythemia vera patients?

PubMed

Crisà, Elena; Cerrano, Marco; Beggiato, Eloise; Benevolo, Giulia; Lanzarone, Giuseppe; Manzini, Paola Maria; Borchiellini, Alessandra; Riera, Ludovica; Boccadoro, Mario; Ferrero, Dario

2017-01-13

Pegylated interferon (peg-IFN) was proven by phase II trials to be effective in polycythemia vera (PV); however, it is not clear whether it could improve patient outcome compared to hydroxyurea (HU). Here, we present an observational study on 65 PV patients aged 65 years or younger, who received either peg-IFN (30) or HU (35) according to the physician choice. Median follow-up was 75 months. The two cohorts were comparable for patient and disease characteristics. Eighty-seven percent of the patients treated with peg-INF responded, with a CR rate of 70% as compared to 100 and 49% with HU, respectively. Discontinuation rate was similar in the two groups (20% in peg-IFN vs 17% in HU). JAK2 allele burden was monitored in peg-INF arm only, and a reduction was observed in 88% of the patients. No thrombotic events were observed during peg-IFN treatment compared to three on HU. Disease progression to myelofibrosis or acute myeloid leukemia occurred to a patient only in peg-INF, compared to three in HU. Overall, three second malignancies were observed during the study, two in patients who received HU only, and one in a patient largely treated HU who received also peg-IFN for 3 months. Overall survival was significantly better for peg-IFN patients compared to HU, p = 0.027. Our study, albeit limited by small patient and event number and lack of randomization, confirms the efficacy of peg-INF in PV and shows a significant survival advantage for peg-INF-treated patients. Waiting for confirming data from the ongoing phase III trials, our study can support peg-INF as a first-line treatment option for PV, at least for younger patients.

Evaluation of dimethoxydop-NU as a novel anti-tumor agent.

PubMed

Mukherjee, A; Dutta, S; Sanyal, U

2007-12-01

Dimethoxydop-NU, 1-[2-{3-(2-Chloroethyl)-3-nitrosoureido}ethyl]-3,4-dimethoxy-benzene (Compound 1), was synthesized from 3,4-dimethoxy-phenethylamine as a novel anti-tumor agent based on the structures of the clinical drug CCNU and dopamine, an important endogenous biological amine having anti-angiogenesis property. In vitro screening in two human tumor cell lines, namely promyelocytic leukemia HL-60 and histiocytic lymphoma U-937, revealed its cytotoxicity greater than that of hydroxyurea and comparable to BCNU used as standards. Its in vivo anti-tumoral potency was assessed in the murine ascites tumors Sarcoma-180 (S-180) and Ehrlich ascites carcinoma (EAC) by measuring the increase in median survival times of drug treated (T) over untreated control (C) mice. Results revealed significant tumor regression effects in these tumors. The survival time of treated mice was markedly increased by combination of the compound 1 with dopamine hydrochloride. Its toxicity was assessed in vivo in normal and EAC bearing mice by measuring drug-induced changes in hematological parameters, femoral bone marrow and splenic cellularities as well as biochemical parameters sequentially on days 9, 14 and 19 following drug treatment at the optimum dose of 30 mg/kg from day 1 to 7. Results indicated that initial suppression in the femoral bone marrow cellularity seen on day 9 reached normalcy by day 19. Other parameters were within normal limit. Histopathological studies of liver revealed mild hepatotoxicity on day 9 in treated groups that substantially recovered on day 19. Similar studies with heart and kidney revealed no cardio toxicity or nephrotoxicity. Compound 1 comparable to standards inhibited the synthesis of DNA and RNA in S-180 tumor cells.

Wasting and stunting are still prevalent in children with sickle cell anaemia in Lagos, Nigeria.

PubMed

Esezobor, Christopher I; Akintan, Patricia; Akinsulie, Adebola; Temiye, Edamisan; Adeyemo, Titilope

2016-05-04

Sickle cell anaemia (SCA) is associated with growth failure. However, recent reports indicate high rates of overweight or obesity among children with SCA in developed countries. It is unclear whether overweight or obesity is also common in children with SCA in developing countries. The objectives of the study were to determine the prevalence of overweight or obesity, wasting and stunting and identify predictors of wasting and stunting among children with SCA in Nigeria. Children with SCA attending a public-funded tertiary hospital clinic were studied. Weight, height, haemoglobin, haemoglobin fractions and white cell count were measured. Anthropometric values were converted to z scores and referenced to the WHO Child Growth Standards and WHO Reference 2007. The proportions with wasting, stunting and overweight or obesity were determined. Regression analysis was used to identify the predictors of wasting and stunting. Two hundred and thirty-three children [mean (±SD) age of 9.0 (±4.0) years, 60.9 % males] participated in the study. Wasting, stunting and overweight or obesity rates were 22.7 %, 11.6 % and 1.7 %, respectively. Boys and children from low socioeconomic class were 3.25 (1.45-7.29) and 2.42 (1.14-5.18) times more likely to be wasted respectively, while both wasting and stunting were more common with increasing age [adjusted OR of 1.33 (1.18-1.51) and 1.15 (1.01-1.32) respectively]. Sickle cell-related complications and intake of oral penicillin and hydroxyurea were not associated with wasting and stunting. Overweight or obesity is uncommon while wasting and stunting are still prevalent in children with SCA in Lagos. The strongest predictors of wasting and stunting were older age, male gender and low socioeconomic status.

The vaccinia virus I3L gene product is localized to a complex endoplasmic reticulum-associated structure that contains the viral parental DNA.

PubMed

Welsch, Sonja; Doglio, Laura; Schleich, Sibylle; Krijnse Locker, Jacomine

2003-05-01

The vaccinia virus (VV) I3L gene product is a single-stranded DNA-binding protein made early in infection that localizes to the cytoplasmic sites of viral DNA replication (S. C. Rochester and P. Traktman, J. Virol. 72:2917-2926, 1998). Surprisingly, when replication was blocked, the protein localized to distinct cytoplasmic spots (A. Domi and G. Beaud, J. Gen. Virol. 81:1231-1235, 2000). Here these I3L-positive spots were characterized in more detail. By using an anti-I3L peptide antibody we confirmed that the protein localized to the cytoplasmic sites of viral DNA replication by both immunofluorescence and electron microscopy (EM). Before replication had started or when replication was inhibited with hydroxyurea or cytosine arabinoside, I3L localized to distinct cytoplasmic punctate structures of homogeneous size. We show that these structures are not incoming cores or cytoplasmic sites of VV early mRNA accumulation. Instead, morphological and quantitative data indicate that they are specialized sites where the parental DNA accumulates after its release from incoming viral cores. By EM, these sites appeared as complex, electron-dense structures that were intimately associated with the cellular endoplasmic reticulum (ER). By double labeling of cryosections we show that they contain DNA and a viral early protein, the gene product of E8R. Since E8R is a membrane protein that is able to bind to DNA, the localization of this protein to the I3L puncta suggests that they are composed of membranes. The results are discussed in relation to our previous data showing that the process of viral DNA replication also occurs in close association with the ER.

A novel component from citrus, ginger, and mushroom family exhibits antitumor activity on human meningioma cells through suppressing the Wnt/β-catenin signaling pathway.

PubMed

Das, Arabinda; Miller, Rickey; Lee, Philip; Holden, Chrysanthe Alyssa; Lindhorst, Scott M; Jaboin, Jerry; Vandergrift, William A; Banik, Naren L; Giglio, Pierre; Varma, Abhay K; Raizer, Jeffery J; Patel, Sunil J

2015-09-01

Recurrent meningiomas constitute an uncommon but significant problem after standard (surgery and radiation) therapy failure. Current chemotherapies (hydroxyurea, RU-486, and interferon-α) are only of marginal benefit. There is an urgent need for more effective treatments for meningioma patients who have failed surgery and radiation therapy. Limonin, Tangeritin, Zerumbone, 6-Gingerol, Ganoderic Acid A, and Ganoderic Acid DM are some of the plant derivatives that have anti-tumorgenic properties and cause cell death in meningioma cells in vitro. Due to its ease of administration, long-term tolerability, and low incidence of long-term side effects, we explored its potential as a therapeutic agent against meningiomas by examining their efficacy in vitro against meningioma cells. Treatment effects were assessed using MTT assay, Western blot analysis, caspases assay, and DNA fragmentation assay. Results indicated that treatments of IOMM-Lee and CH157MN meningioma cells with Limonin, Tangeritin, Zerumbone, 6-Gingerol, Ganoderic Acid A, and Ganoderic Acid DM induced apoptosis with enhanced phosphorylation of glycogen synthase kinase 3 β (GSK3β) via inhibition of the Wnt5/β-catenin pathway. These drugs did not induce apoptosis in normal human neurons. Other events in apoptosis included downregulation of tetraspanin protein (TSPAN12), survival proteins (Bcl-XL and Mcl-1), and overexpression apoptotic factors (Bax and caspase-3). These results provide preliminary strong evidence that medicinal plants containing Limonin, Tangeritin, 6-Gingerol, Zerumbone, Ganoderic Acid A, and Ganoderic Acid DM can be applied to high-grade meningiomas as a therapeutic agent, and suggests that further in vivo studies are necessary to explore its potential as a therapeutic agent against malignant meningiomas.