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1

Preclinical Toxicology Studies for New Drugs and Vaccines.  

National Technical Information Service (NTIS)

During the reporting period, Two Week Oral Toxicity Studies of WR2425 11 and WR2694 10 in Rats, In Vitro Mutagenicity Tests of WR2425 11 and WR2694 10, Four Week Oral Toxicity Studies of WR2425 11 and WR2694 10 in Dogs, Thirteen Week Oral Toxicity Studies...

B. S. Levine

1994-01-01

2

Preclinical Toxicology and Biodistribution Studies of Recombinant Adeno-Associated Virus 1 Human Acid ?-Glucosidase.  

PubMed

Abstract A biodistribution and toxicology study was performed to test the acute toxicities of intradiaphragmatic injection of a recombinant adeno-associated virus (rAAV) 2/1-human acid alpha-Glucosidase (hGAA) driven by a cytomegalovirus (CMV) promoter (rAAV1-CMV-hGAA) in New Zealand white rabbits and in the rodent Pompe disease model by injecting at the right quadriceps. Studies performed using fluoroscopy and AAV2-GFP demonstrated spread upon intradiaphragmatic injection, and the ability of AAV to infect and express acid ?-glucosidase (GAA) throughout the diaphragm. For the preclinical study, 10 rabbits (5 male, 5 female) were divided into two groups, vehicle control (Lactated Ringer's) and test article (1.5×10(12) vector genomes [vg] rAAV1-CMV-hGAA), and euthanized on day 21. After direct visualization, the left hemidiaphragm was injected at three locations. There was up to a 2,500-fold increase in circulating anti-AAV1 antibodies directed to the vector capsids. In addition, up to an 18-fold increase in antibodies against the GAA protein was generated. Injection sites maintained up to 1.0×10(5) vg/?g genomic DNA (gDNA), while uninjected sites had up to 1.0×10(4) vg/?g gDNA. Vector DNA was present in blood at 24?hr postinjection at up to 1.0×10(6) vg/?g gDNA, followed by a decrease to 1.0×10(3) vg/?g gDNA at euthanization on day 21. Nominal amounts of vector DNA were present in peripheral organs, including the brain, spinal cord, gonads, and skeletal muscle. Upon histopathological examination, fibroplasias of the serosal surface were noted at diaphragm injections sites of both groups. In addition, an increase in mononuclear cell infiltration in the diaphragm and esophagus in vector-dosed animals was found. Elevated creatine phosphokinase levels, an indicator of muscle repair, was observed in all animals postprocedure but persisted in vector-injected rabbits until euthanization. A follow-up study suggested that this was directed against the human transgene expression in a foreign species. Overall, this study demonstrates diffusion of vector throughout the diaphragm after localized injections. PMID:24021025

Conlon, Thomas J; Erger, Kirsten; Porvasnik, Stacy; Cossette, Travis; Roberts, Cheryl; Combee, Lynn; Islam, Saleem; Kelley, Jeffry; Cloutier, Denise; Clément, Nathalie; Abernathy, Corinne R; Byrne, Barry J

2013-09-01

3

Preclinical Toxicology of Nsc 1895 Administered By 24-Hour Infusion in Dogs. Part II.  

National Technical Information Service (NTIS)

NSC 1895, Guanazole, Triazole 3, 5-diamino-s, which shows strong antitumor activity has been studied for preclinical toxicological effects following weekly 24-hour infusions in young adult beagle dogs. At all dosage levels, clinical signs of toxicity were...

P. E. Palm M. S. Nick C. J. Kensler D. A. Cooney R. D. Davis

1969-01-01

4

Preclinical Toxicology of Nsc 17251E Administered by Oral Route in Dogs. Part II.  

National Technical Information Service (NTIS)

NSC 17251E* has been studied for preclinical toxicological effects following repeated oral administration in young adult beagle dogs. All animals survived the 28-day treatment, and no serious clinical signs of toxicity were noted with dosages of 168, 336,...

P. E. Palm M. S. Nick C. J. Kensler D. A. Cooney R. D. Davis

1969-01-01

5

Preclinical Toxicology Study of Guanazole (Nsc 1895) Administered by 48-Hour Infusion in Dogs. Part III.  

National Technical Information Service (NTIS)

NSC 1895, Guanazole, Triazole 3,5-diamino-s, which shows strong antitumor activity against L1210 in mic3 when administered by the intraperitoneal route, and moderate activity by the intravenous, oral, intramuscular, and subcutaneous routes, has been studi...

P. E. Palm G. J. Kensler

1970-01-01

6

Phospholipogenic pharmaceuticals are associated with a higher incidence of histological findings than nonphospholipogenic pharmaceuticals in preclinical toxicology studies.  

PubMed

While phospholipidosis is thought to be an adaptive response to chemical challenge, many phospholipogenic compounds are known to display adverse effects in preclinical species and humans. To investigate the link between phospholipogenic administration and incidence of preclinical histological signals, an internal AstraZeneca in vivo toxicology report database was searched to identify phospholipogenic and nonphospholipogenic compounds. The datasets assembled comprised 46 phospholipogenic and 62 nonphospholipogenic compounds. The phospholipogenic potential of these compounds was confirmed by a pathologist's interpretation and was supported by well-validated in silico and in vitro models. The phospholipogenic dataset contained 37 bases, 4 neutral compounds, 3 zwitterions, and 1 acid, whereas the nonphospholipogenic dataset contained 9 bases, 34 neutrals, 1 zwitterion, and 18 acids. Histologic findings were tracked for adrenal gland; bone marrow; kidney; liver; lung; lymph node; spleen; thymus; and reproductive organs. On average, plasma exposures were higher in animals dosed with the nonphospholipogenics. Phospholipogenics yielded proportionally more histologic changes (exclusive of phospholipidosis itself) in all organs. Statistically significant higher frequencies of liver necrosis, alveolitis/pneumonitis, as well as lymphocytolysis in the thymus, lymph nodes, and spleen occurred in response to phospholipogenics compared to that for nonphospholipogenics. PMID:22745636

Barone, Linda R; Boyer, Scott; Damewood, James R; Fikes, James; Ciaccio, Paul J

2012-06-14

7

Phospholipogenic Pharmaceuticals Are Associated with a Higher Incidence of Histological Findings than Nonphospholipogenic Pharmaceuticals in Preclinical Toxicology Studies  

PubMed Central

While phospholipidosis is thought to be an adaptive response to chemical challenge, many phospholipogenic compounds are known to display adverse effects in preclinical species and humans. To investigate the link between phospholipogenic administration and incidence of preclinical histological signals, an internal AstraZeneca in vivo toxicology report database was searched to identify phospholipogenic and nonphospholipogenic compounds. The datasets assembled comprised 46 phospholipogenic and 62 nonphospholipogenic compounds. The phospholipogenic potential of these compounds was confirmed by a pathologist's interpretation and was supported by well-validated in silico and in vitro models. The phospholipogenic dataset contained 37 bases, 4 neutral compounds, 3 zwitterions, and 1 acid, whereas the nonphospholipogenic dataset contained 9 bases, 34 neutrals, 1 zwitterion, and 18 acids. Histologic findings were tracked for adrenal gland; bone marrow; kidney; liver; lung; lymph node; spleen; thymus; and reproductive organs. On average, plasma exposures were higher in animals dosed with the nonphospholipogenics. Phospholipogenics yielded proportionally more histologic changes (exclusive of phospholipidosis itself) in all organs. Statistically significant higher frequencies of liver necrosis, alveolitis/pneumonitis, as well as lymphocytolysis in the thymus, lymph nodes, and spleen occurred in response to phospholipogenics compared to that for nonphospholipogenics.

Barone, Linda R.; Boyer, Scott; Damewood, James R.; Fikes, James; Ciaccio, Paul J.

2012-01-01

8

Preclinical toxicological evaluation of sertraline hydrochloride.  

PubMed

The toxicity profile of the antidepressant drug sertraline was determined in a series of preclinical studies in mice, rats, rabbits and dogs. Acute, subchronic, reproductive, chronic and carcinogenicity studies were conducted by the oral route. The highest doses tested in these studies were the maximum tolerated doses based on clinical signs, decreased food consumption, body weight effects, organ weight changes or clinical/anatomical pathology findings. Genetic toxicity studies were also performed. The liver was identified as a target organ in the mouse, rat and dog. The observed liver findings were consistent with hepatic xenobiotic-metabolizing enzyme induction and included hepatomegaly, hepatocellular hypertrophy, slightly increased serum transaminase activity and proliferation of smooth endoplasmic reticulum. Hepatocellular fatty change, a minimal toxic effect, was seen in mice and rats. There was no teratogenicity in studies conducted at maternally toxic doses in rats and rabbits. Decreased neonatal survival and growth observed in these studies have been previously reported in reproduction studies with other serotonin reuptake inhibitors. Sertraline was not genotoxic in an extensive battery of tests. Carcinogenicity tests were negative in rats, while benign liver tumors were slightly increased in drugtreated male mice. Liver tumors were considered secondary to the enzyme inducing potential of sertraline and not indicative of human risk. PMID:9598298

Davies, T S; Klowe, W M

1998-05-01

9

Preclinical toxicological evaluation of sertraline hydrochloride.  

PubMed

The toxicity profile of the antidepressant drug sertraline was determined in a series of preclinical studies in mice, rats, rabbits and dogs. Acute, subchronic, reproductive, chronic and carcinogenicity studies were conducted by the oral route. The highest doses tested in these studies were the maximum tolerated doses based on clinical signs, decreased food consumption, body weight effects, organ weight changes or clinical/anatomical pathology findings. Genetic toxicity studies were also performed. The liver was identified as a target organ in the mouse, rat and dog. The observed liver findings were consistent with hepatic xenobiotic-metabolizing enzyme induction and included hepatomegaly, hepatocellular hypertrophy, slightly increased serum transaminase activity and proliferation of smooth endoplasmic reticulum. Hepatocellular fatty change, a minimal toxic effect, was seen in mice and rats. There was no teratogenicity in studies conducted at maternally toxic doses in rats and rabbits. Decreased neonatal survival and growth observed in these studies have been previously reported in reproduction studies with serotonin reuptake inhibitors. Sertraline was not genotoxic in an extensive battery of tests. Carcinogenicity tests were negative in rats, while benign liver tumors were slightly increased in drug-treated male mice. Liver tumors were considered secondary to the enzyme inducing potential of sertraline and not indicative of human risk. PMID:10048942

Davies, T S; Kluwe, W M

1998-11-01

10

The Role of Transcriptome Analysis in PreClinical Toxicology  

Microsoft Academic Search

A major benefit of the genomics revolution in biomedical research has been the establishment of transcriptome analysis as an enabling technology in the drug development process. Nowhere in the realm of drug development has the expectation of the impact of transcriptome analysis been greater than in the area of pre-clinical toxicology. Transcriptome analysis, along with other new high-content data generating

George H. Searfoss; Timothy P. Ryan; Robert A. Jolly

2005-01-01

11

Preclinical and Toxicology Studies of 1263W94, a Potent and Selective Inhibitor of Human Cytomegalovirus Replication  

Microsoft Academic Search

1263W94 is a novel benzimidazole compound being developed for treatment of human cytomegalovirus in- fection. No adverse pharmacological effects were demonstrated in safety pharmacology studies with 1263W94. The minimal-effect dose in a 1-month rat study was 100 mg\\/kg\\/day, and the no-effect dose in a 1-month monkey study was 180 mg\\/kg\\/day. Toxic effects were limited to increases in liver weights, neutrophils,

George W. Koszalka; Nelson W. Johnson; Steven S. Good; Leslie Boyd; Stanley C. Chamberlain; Leroy B. Townsend; John C. Drach; Karen K. Biron

2002-01-01

12

Preclinical toxicology studies for new drugs and vaccines. Annual report, 15 November 1991-14 November 1992  

SciTech Connect

The purpose of this study is to determine specific target organ toxicity, dose-response relationships, and a no adverse effect level of WR6026 in Beagle dogs following thirteen weeks of daily oral administration. In addition, the reversibility of these toxic effects over a 90-day recovery period will be assessed. Treatment was initiated on 5/7/92. Necropsies were conducted on 8/6-7/92 and 11/5-6/92 after the three month treatment period and a three month recovery period, respectively.

Levine, B.S.

1992-12-07

13

Preclinical Pharmacology and Toxicology Studies  

Cancer.gov

OF RECEIPT for determining TIMELY DELIVERY is the address provided for the OFFICE OF ACQUISITIONS. IF YOUR PROPOSAL IS NOT RECEIVED BY THE CONTRACTING OFFICER OR HIS DESIGNEE AT THE PLACE AND TIME SPECIFIED FOR THE OFFICE OF ACQUISITIONS, THEN IT WILL BE CONSIDERED LATE AND HANDLED IN ACCORDANCE WITH subparagraph (c)(3) of FAR Clause 52.215-1, Instructions to Offerors--Competitive Acquisition," LOCATED IN SECTION L.1. OF THIS SOLICITATION. 10.

14

Preclinical Pharmacology and Toxicology of Intravenous MV-NIS, an Oncolytic Measles Virus Administered With or Without Cyclophosphamide  

Microsoft Academic Search

MV-NIS is an oncolytic measles virus encoding the human thyroidal sodium iodide symporter (NIS). Here, we report the results of preclinical pharmacology and toxicology studies conducted in support of our clinical protocol “Phase I Trial of Systemic Administration of Edmonston Strain of Measles Virus, Genetically Engineered to Express NIS, with or without Cyclophosphamide, in Patients with Recurrent or Refractory Multiple

R M Myers; S M Greiner; M E Harvey; G Griesmann; M J Kuffel; S A Buhrow; J M Reid; M Federspiel; M M Ames; D Dingli; K Schweikart; A Welch; A Dispenzieri; K-W Peng; S J Russell

2007-01-01

15

AMT: preclinical pharmacology studies.  

PubMed

Auron-Misheil-Therapy (AMT) consisting of aqueous camomile extract supplemented with calcium, vitamins, the antihistamine chlorpheniramine and human insulin is under development as anti-cancer treatment. AMT was preclinically investigated in tumour cell lines and tumour xenografts to guide clinical phase I/II studies. AMT was tested against 56 human tumour cell lines, in a clonogenic assay in 98 patient-derived xenografts and in in vivo studies. AMT showed in vitro cytotoxic activity with highest susceptibility in cervical cancer, glioblastoma and colon cancers. In the clonogenic assay, anti- cancer activity of AMT was most active in cervical and uterine tumours, in colon cancer, glioblastoma, leukaemia, melanoma and pancreatic cancer. In vivo, AMT showed slight activity in tumour xenograft models of colon and mammary cancer. It also showed immune stimulatory effects by induction of IL-6- and TNF-alpha secretion in human PBMCs. The immune stimulatory potential of AMT, together with slight anti-tumour efficacy observed in the present study, indicates a role of AMT in tumour therapy. PMID:19360346

Niazi, Faiz; Drevs, Joachim; Diergarten, Klaus; Dorn, Annette; Maier, Armin; Fiebig, Heinz Herbert; Bruyns, Eddy; Scheele, Jürgen

2009-05-01

16

Preclinical safety, toxicology, and biodistribution study of adenoviral gene therapy with sVEGFR-2 and sVEGFR-3 combined with chemotherapy for ovarian cancer.  

PubMed

Abstract Antiangiogenic and antilymphangiogenic gene therapy with soluble vascular endothelial growth factor receptor-2 (VEGFR-2) and soluble VEGFR-3 in combination with chemotherapy is a potential new treatment for ovarian carcinoma. We evaluated the safety, toxicology, and biodistribution of intravenous AdsVEGFR-2 and AdsVEGFR-3 combined with chemotherapy in healthy rats (n=90) before entering a clinical setting. The study groups were: AdLacZ and AdLacZ with chemotherapy as control groups, low dose AdsVEGFR-2 and AdsVEGFR-3, high dose AdsVEGFR-2 and AdsVEGFR-3, combination of low dose AdsVEGFR-2 and AdsVEGFR-3 with chemotherapy, combination of high dose AdsVEGFR-2 and AdVEGFR-3 with chemotherapy, and chemotherapy only. The follow-up time was 4 weeks. Safety and toxicology were assessed by monitoring the clinical status of the animals and by histological, hematological, and clinical chemistry parameters. For the biodistribution studies, quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were used. Low dose (2×10(10) vp) AdsVEGFR-2 and AdsVEGFR-3 gene therapy was well tolerated, even when gene therapy was combined with chemotherapy. Notably, only transient elevation of liver enzymes and mild regenerative changes were seen in liver after the gene transfer in the groups that received high doses (2×10(11) vp) of AdsVEGFR-2 and AdsVEGFR-3 with or without chemotherapy. No life-threatening adverse effects were noticed in any of the treatment groups. The highest protein concentration of soluble VEGFR-2 (sVEGFR-2) in circulation was seen 1 week after the gene transfer. The combination of chemotherapy to gene therapy seemed to prolong the time of detectable transgene protein at least 1 week in the circulation. The expression of AdsVEGFR-2 and AdsVEGFR-3 transgenes was mainly seen in the liver and spleen as detected by qRT-PCR. According to these results, AdsVEGFR-2 and AdsVEGFR-3 gene therapy combined with chemotherapy is safe and can be brought to clinical testing in ovarian cancer patients. PMID:23692381

Tuppurainen, Laura; Sallinen, Hanna; Kokki, Emmi; Koponen, Jonna; Anttila, Maarit; Pulkkinen, Kati; Heikura, Tommi; Toivanen, Pyry; Hämäläinen, Kirsi; Kosma, Veli-Matti; Heinonen, Seppo; Alitalo, Kari; Ylä-Herttuala, Seppo

2013-04-03

17

Preclinical Toxicology Studies of Recombinant Human Platelet-Derived Growth Factor-BB Either Alone or in Combination with Beta-Tricalcium Phosphate and Type I Collagen.  

PubMed

Human platelet-derived growth factor-BB (hPDGF-BB) is a basic polypeptide growth factor released from platelets at the injury site. It is a multifunctional molecule that regulates DNA synthesis and cell division and induces biological effects that are implicated in tissue repair, atherosclerosis, inflammatory responses, and neoplastic diseases. This paper is an overview of the toxicology data generated from a broad testing platform to determine bone, soft tissue, and systemic responses following administration of rhPDGF-BB. Moreover, the systemic and local toxicity of recombinant human PDGF-BB (rhPDGF-BB) in combination with either beta-tricalcium phosphate (?-TCP) or collagen combined with ?-TCP was studied to determine dermal sensitization, irritation, intramuscular tissue responses, pyrogenicity, genotoxicity, and hemolytic properties. All data strongly suggest that rhPDGF-BB either alone or in combination with ?-TCP or collagen with ?-TCP is biocompatible and has neither systemic nor local toxicity, supporting its safe use in enhancing wound healing in patients. PMID:21350649

Young, Conan S; Bradica, Gino; Hart, Charlie E; Karunanidhi, Anuradha; Street, Reva M; Schutte, Lyndsey; Hollinger, Jeffrey O

2011-01-10

18

Improving Toxicology Knowledge in Preclinical Medical Students Using High-Fidelity Patient Simulators  

PubMed Central

Background Superior patient care and optimal physician training are often mutually elusive in the Emergency Department setting. Highfidelity patient simulators (HFPSs) are being used with increasing frequency in the training of medical students (MS) because they enable students to develop and refine medical competency in a non-threatening and safe environment. However, learner outcomes using HFPSs in this setting have not been well studied. Objectives The objective of this pilot study was to determine the effectiveness of HFPSs in simulation (SIM) training as a learning tool for preclinical second-year MS to further increase their toxicology knowledge. Methods Second-year MS at a Problem Based Learning (PBL) medical school received a PBL toxicology teaching session in the middle of the semester. One week later, the students participated in a SIM exercise based on issues taken from the PBL case. The SIM exercise required that students address learning issues such as identifying abnormal findings, ordering tests, and, ultimately, initiating treatment on a full-scale HFPS mannequin. A supervised on-line test consisting of 10 multiple choice questions regarding the student's understanding of the learning issues was completed before the PBL class and directly before and after the SIM to determine the effectiveness of the HFPS use. Immediate video-assisted feedback was provided by emergency medicine attendings. Results Use of HFPSs during SIM exercises and in combination with PBL significantly increased toxicology knowledge in secondyear MS as determined by the improvement of on-line test scores (% correct answers) from 59% before PBL / before SIM to 69% after PBL / before SIM to 80% after PBL / after SIM. Conclusion This study suggests that HFPS may be a valuable tool in helping to improve toxicology knowledge in second-year MS at a key transition period prior to beginning clerkship experiences. Incorporation of HFPS into PBL curricula may also be beneficial to MS in other areas of study where interactive learning could assist in evoking emotional realism while also enhancing critical thinking and acquisition of knowledge thereby facilitating the transition from theory to practice.

Lee, Meta T; Franke, Adrian A

2011-01-01

19

Developing combination drugs in preclinical studies.  

PubMed

Although combination drugs have been available for many years, it is only recently that preclinical guidelines have been released by the Food and Drugs Administration (FDA) and EMEA and as yet they are not part of the ICH process. In addition, the World Health Organisation and FDA have issued guidelines for combination drugs developed specifically to treat HIV infections. Depending on the type of combination (marketed drug/marketed drug; marketed drug/NME and NME/NME), the scope and complexity of studies can vary greatly. In all cases, however, a key issue is the potential for pharmacokinetic and/or toxicologic interaction between the components. For a marketed drug/marketed drug combination, a detailed review of the preclinical data available may suffice; particularly when the components have a history of co-administration at about the same dose and ratio as that of the proposed combination. For a marketed drug/NME combination, in addition to a review of the data for the marketed drug, a full ICH programme of studies will be required for the NME, and a study of up to 90 days duration (in one species) for the combination. With an NME/NME combination, each component will require a full ICH battery of studies and a combination study in one species. In all cases, additional studies may be needed to address data gaps. Given the many novel and complex issues that arise when developing combination drugs, we recommend that, whenever possible, the preclinical study strategy is discussed with the regulatory authorities. PMID:20972744

Lodola, Alberto

2011-01-01

20

Application of population pharmacokinetics for preclinical safety and efficacy studies.  

PubMed

From the beginning of the 1980s, population PK has been primarily used in clinical development and only in the last decade has it been convincingly applied in a preclinical setting. Sparse sampling and covariate analyses are key features of preclinical popPK, useful for toxicology and efficacy studies in animals to assemble data obtained from different studies; for describing individual PK and PD; for building mechanistic models; and for performing interspecies scaling-up of disposition and efficacy. Application in disease models, mainly in behavioral and neurological models, allows the quantitative description of PK and PD without frequent blood sampling and recurrent physiological measurements, which are the critical and compromising perturbations of experimental systems. A preclinical population approach to PK and PD, by its versatility and possibility of simulating 'what if' scenarios, offers a unique and potent tool in the development of new drugs, in particular biologics. PMID:23937139

Porzio, Stefano

2013-08-01

21

Mixed chimerism: Preclinical studies and clinical applications  

Microsoft Academic Search

Traditional approaches to allogeneic stem cell transplantation have relied on the use of toxic high-dose conditioning therapy to achieve allogeneic engraftment and control of underlying disease. Preclinical observations have shown that, for engraftment purposes, conditioning regimens can be reduced in intensity, resulting in reduced treatment toxicities. In preclinical canine studies, the use of potent pre- and postgrafting immunosuppression allowed for

Peter A McSweeney; Rainer Storb

1999-01-01

22

Concordance of preclinical and clinical pharmacology and toxicology of monoclonal antibodies and fusion proteins: soluble targets  

PubMed Central

Monoclonal antibodies (mAbs) and fusion proteins directed towards soluble targets make an important contribution to the treatment of disease. The purpose of this review was to correlate the clinical and preclinical data on the 14 currently approved mAbs and fusion proteins targeted to soluble targets. The principal sources used to gather data were: the peer reviewed Literature; European Medicines Agency ‘Scientific Discussions’ and United States Food and Drug Administration ‘Pharmacology/Toxicology Reviews’ and package inserts (United States Prescribing Information). Data on the following approved biopharmaceuticals were included: adalimumab, anakinra, bevacizumab, canakinumab, certolizumab pegol, denosumab, eculizumab, etanercept, golimumab, infliximab, omalizumab, ranibizumab, rilonacept and ustekinumab. Some related biopharmaceuticals in late-stage development were also included for comparison. Good concordance with human pharmacodynamics was found for both non-human primates (NHPs) receiving the human biopharmaceutical and mice receiving rodent homologues (surrogates). In contrast, there was limited concordance for human adverse effects in genetically deficient mice, mice receiving surrogates or NHPs receiving the human pharmaceutical. In summary, the results of this survey show that although both mice and NHPs have good predictive value for human pharmacodynamics, neither species have good predictive value for human adverse effects. No evidence that NHPs have superior predictive value was found.

Martin, Pauline L; Bugelski, Peter J

2012-01-01

23

Preclinical Pharmacology and Toxicology of Intravenous MV-NIS, an Oncolytic Measles Virus Administered With or Without Cyclophosphamide  

PubMed Central

MV-NIS is an oncolytic measles virus encoding the human thyroidal sodium iodide symporter (NIS). Here, we report the results of preclinical pharmacology and toxicology studies conducted in support of our clinical protocol “Phase I Trial of Systemic Administration of Edmonston Strain of Measles Virus, Genetically Engineered to Express NIS, with or without Cyclophosphamide, in Patients with Recurrent or Refractory Multiple Myeloma.” Dose–response studies in the KAS-6/1 myeloma xenograft model demonstrated a minimum effective dose of 4 × 106 TCID50 (tissue culture infectious dose 50)/kg. Toxicity studies in measles-naive squirrel monkeys and measles-susceptible transgenic mice were negative at intravenous doses up to 108 and 4 × 108 TCID50/kg, respectively. Abundant viral mRNA, maximal on day 8, was detected in cheek swabs of squirrel monkeys, more so after pretreatment with cyclophosphamide. On the basis of these data, the safe starting dose of MV-NIS for our clinical protocol was set at 1 – 2 × 104 TCID50/kg (106 TCID50 per patient).

Myers, RM; Greiner, SM; Harvey, ME; Griesmann, G; Kuffel, MJ; Buhrow, SA; Reid, JM; Federspiel, M; Ames, MM; Dingli, D; Schweikart, K; Welch, A; Dispenzieri, A; Peng, K-W; Russell, SJ

2009-01-01

24

Preclinical studies of low back pain  

PubMed Central

Chronic low back pain is a major cause of disability and health care costs. Current treatments are inadequate for many patients. A number of preclinical models have been developed that attempt to mimic aspects of clinical conditions that contribute to low back pain. These involve application of nucleus pulposus material near the lumbar dorsal root ganglia (DRG), chronic compression of the DRG, or localized inflammation of the DRG. These models, which are primarily implemented in rats, have many common features including behavioral hypersensitivity of the hindpaw, enhanced excitability and spontaneous activity of sensory neurons, and locally elevated levels of inflammatory mediators including cytokines. Clinically, epidural injection of steroids (glucocorticoids) is commonly used when more conservative treatments fail, but clinical trials evaluating these treatments have yielded mixed results. There are relatively few preclinical studies of steroid effects in low back pain models. One preclinical study suggests that the mineralocorticoid receptor, also present in the DRG, may have pro-inflammatory effects that oppose the activation of the glucocorticoid receptor. Although the glucocorticoid receptor is the target of anti-inflammatory steroids, many clinically used steroids activate both receptors. This could be one explanation for the limited effects of epidural steroids in some patients. Additional preclinical research is needed to address other possible reasons for limited efficacy of steroids, such as central sensitization or presence of an ongoing inflammatory stimulus in some forms of low back pain.

2013-01-01

25

Performance of Novel Kidney Biomarkers in Preclinical Toxicity Studies  

PubMed Central

The kidney is one of the main targets of drug toxicity, but early detection of renal damage is often difficult. As part of the InnoMed PredTox project, a collaborative effort aimed at assessing the value of combining omics technologies with conventional toxicology methods for improved preclinical safety assessment, we evaluated the performance of a panel of novel kidney biomarkers in preclinical toxicity studies. Rats were treated with a reference nephrotoxin or one of several proprietary compounds that were dropped from drug development in part due to renal toxicity. Animals were dosed at two dose levels for 1, 3, and 14 days. Putative kidney markers, including kidney injury molecule-1 (Kim-1), lipocalin-2 (Lcn2), clusterin, and tissue inhibitor of metalloproteinases-1, were analyzed in kidney and urine using quantitative real-time PCR, ELISA, and immunohistochemistry. Changes in gene/protein expression generally correlated well with renal histopathological alterations and were frequently detected at earlier time points or at lower doses than the traditional clinical parameters blood urea nitrogen and serum creatinine. Urinary Kim-1 and clusterin reflected changes in gene/protein expression and histopathological alterations in the target organ in the absence of functional changes. This confirms clusterin and Kim-1 as early and sensitive, noninvasive markers of renal injury. Although Lcn2 did not appear to be specific for kidney toxicity, its rapid response to inflammation and tissue damage in general may suggest its utility in routine toxicity testing.

Hoffmann, Dana; Adler, Melanie; Vaidya, Vishal S.; Rached, Eva; Mulrane, Laoighse; Gallagher, William M.; Callanan, John J.; Gautier, Jean C.; Matheis, Katja; Staedtler, Frank; Dieterle, Frank; Brandenburg, Arnd; Sposny, Alexandra; Hewitt, Philip; Ellinger-Ziegelbauer, Heidrun; Bonventre, Joseph V.; Dekant, Wolfgang; Mally, Angela

2010-01-01

26

Performance of novel kidney biomarkers in preclinical toxicity studies.  

PubMed

The kidney is one of the main targets of drug toxicity, but early detection of renal damage is often difficult. As part of the InnoMed PredTox project, a collaborative effort aimed at assessing the value of combining omics technologies with conventional toxicology methods for improved preclinical safety assessment, we evaluated the performance of a panel of novel kidney biomarkers in preclinical toxicity studies. Rats were treated with a reference nephrotoxin or one of several proprietary compounds that were dropped from drug development in part due to renal toxicity. Animals were dosed at two dose levels for 1, 3, and 14 days. Putative kidney markers, including kidney injury molecule-1 (Kim-1), lipocalin-2 (Lcn2), clusterin, and tissue inhibitor of metalloproteinases-1, were analyzed in kidney and urine using quantitative real-time PCR, ELISA, and immunohistochemistry. Changes in gene/protein expression generally correlated well with renal histopathological alterations and were frequently detected at earlier time points or at lower doses than the traditional clinical parameters blood urea nitrogen and serum creatinine. Urinary Kim-1 and clusterin reflected changes in gene/protein expression and histopathological alterations in the target organ in the absence of functional changes. This confirms clusterin and Kim-1 as early and sensitive, noninvasive markers of renal injury. Although Lcn2 did not appear to be specific for kidney toxicity, its rapid response to inflammation and tissue damage in general may suggest its utility in routine toxicity testing. PMID:20118187

Hoffmann, Dana; Adler, Melanie; Vaidya, Vishal S; Rached, Eva; Mulrane, Laoighse; Gallagher, William M; Callanan, John J; Gautier, Jean C; Matheis, Katja; Staedtler, Frank; Dieterle, Frank; Brandenburg, Arnd; Sposny, Alexandra; Hewitt, Philip; Ellinger-Ziegelbauer, Heidrun; Bonventre, Joseph V; Dekant, Wolfgang; Mally, Angela

2010-01-29

27

Preclinical Studies of Novel Targeted Therapies  

PubMed Central

Summary The bone marrow (BM) milieu confers drug resistance in multiple myeloma (MM) cells to conventional therapies. Therefore novel biologically-based therapies are needed. Preclinical studies have identified and validated molecular targeted therapeutics in MM. In particular, recognition of the biologic significance of the BM microenvironment both in MM pathogenesis and as a potential target for novel therapeutics has already derived several promising approaches. Thalidomide, lenalidomide (Revlimid®) and bortezomib (Velcade®) are directed not only at MM cells, but also BM milieu, and have rapidly from the bench to the bedside and FDA approval to treat MM.

Hideshima, Teru; Anderson, Kenneth C.

2008-01-01

28

An Indexing Coverage Study of Toxicological Literature  

ERIC Educational Resources Information Center

The goal of this study was an appraisal of indexing coverage for the interdisciplinary field of toxicology. Information of research significance was limited to primary literature, defined as published documents containing original data from experimental work or case studies. (6 references) (Author/NH)

Montgomery, Ruth Reinke

1973-01-01

29

An Indexing Coverage Study of Toxicological Literature  

ERIC Educational Resources Information Center

|The goal of this study was an appraisal of indexing coverage for the interdisciplinary field of toxicology. Information of research significance was limited to primary literature, defined as published documents containing original data from experimental work or case studies. (6 references) (Author/NH)|

Montgomery, Ruth Reinke

1973-01-01

30

Concordance of preclinical and clinical pharmacology and toxicology of therapeutic monoclonal antibodies and fusion proteins: cell surface targets  

PubMed Central

Monoclonal antibodies (mAbs) and fusion proteins directed towards cell surface targets make an important contribution to the treatment of disease. The purpose of this review was to correlate the clinical and preclinical data on the 15 currently approved mAbs and fusion proteins targeted to the cell surface. The principal sources used to gather data were: the peer reviewed Literature; European Medicines Agency ‘Scientific Discussions’; and the US Food and Drug Administration ‘Pharmacology/Toxicology Reviews’ and package inserts (United States Prescribing Information). Data on the 15 approved biopharmaceuticals were included: abatacept; abciximab; alefacept; alemtuzumab; basiliximab; cetuximab; daclizumab; efalizumab; ipilimumab; muromonab; natalizumab; panitumumab; rituximab; tocilizumab; and trastuzumab. For statistical analysis of concordance, data from these 15 were combined with data on the approved mAbs and fusion proteins directed towards soluble targets. Good concordance with human pharmacodynamics was found for mice receiving surrogates or non-human primates (NHPs) receiving the human pharmaceutical. In contrast, there was poor concordance for human pharmacodynamics in genetically deficient mice and for human adverse effects in all three test systems. No evidence that NHPs have superior predictive value was found.

Bugelski, Peter J; Martin, Pauline L

2012-01-01

31

Endpoints for Prenatal Exposures in Toxicological Studies  

Microsoft Academic Search

The standard approach to developmental toxicology includes, 1) studies targeting the organogenesis\\/pregnancy period, to assess\\u000a birth defects, minor anomalies (that may be a signal of more severe effects at higher dose levels), fetal growth and viability\\u000a (OECD guideline 414); 2) one- and two-generation studies (OECD guidelines 415 and 416) that provide an overall assessment\\u000a of general parameters related to postnatal

A. Mantovani; F. Maranghi

32

Love Canal: environmental and toxicological studies  

SciTech Connect

The New York State Department of Health has been involved at the Love Canal since 1978. The State has carried out numerous environmental and toxicological studies. The major purposes for these studies were to define how Love Canal contaminants might be escaping into the environment at large, what paths contaminant migration might take, and what toxicological effects Love Canal chemicals might have individually and together. Although underground contaminant migration was hypothesized along swales and underground utility bedding, these mechanisms have been proven not to be operative except for some migration along the utility bedding under Frontier Avenue. In general no underground migration has occurred outside the confines of the three city blocks that contain the Love Canal referred to as the ''first ring''. Studies have been confused by apparent burial of waste materials in areas proximate but not directly connected to the Love Canal. Migration of Love Canal leachate has occurred through storm sewers. Love Canal contaminants have reached creeks to the north and the Niagara River to the south through storm sewer transport. In spite of finding 2, 3, 7, 8 tetrachlorodibenzoparadioxin (TCDD), toxicological studies in situ and through exposure to volatile components in Love Canal soils do not indicate unusual toxicity. Animal studies continue in an attempt to determine the teratogenic and fetotoxic potential of Love Canal chemicals under different routes of exposure.

Kim, C.S.

1981-01-01

33

Preclinical Toxicology of Nsc 1895 Administered by 24-Hour Infusion in Dogs.  

National Technical Information Service (NTIS)

NSC 1895, Guanazole, Triazole 3,5-diamino-s, which shows strong antitumor activity against L1210 in mice when administered by the intraperitoneal route, and moderate activity by the intravenous, oral, intramuscular, and subcutaneous routes, has been studi...

P. E. Palm M. S. Nick C. J. Kensler P. S. Schein R. D. Davis

1968-01-01

34

Toxicological study of Balacaturbhadrika churna  

PubMed Central

Balacaturbhadrika churna has an important place in pediatric practice in Ayurveda. Millennia of use of this formulation bears testimony to its safety when used for prolonged duration in children. This prompted us to initiate a long-term, acute oral toxicity evaluation of Balacaturbhadrika churna in rats. The study was carried out by administering Balacaturbhadrika churna orally once only in a dose up to 2000 mg/kg. For long-term toxicity, Balacaturbhadrika churna was administered in doses of 450 and 900 mg/kg orally for 45 consecutive days. The effects of the drug on ponderal changes, hematological, biochemical and histological parameters were noted. The acute toxicity experiment showed that the drug did not produce any signs and symptoms of toxicity (or mortality) up to the dose of 2000 mg/kg. Long-term toxicity results showed that, even at higher dose of 900 mg/kg, Balacaturbhadrika churna did not affect the parameters studied, to a significant extent. The doses employed for these toxicity studies were several times higher than normal clinical doses of Balacaturbhadrika churna, hence the observed changes will probably not become apparent at therapeutic dose level.

Nariya, Mukeshkumar B.; Parmar, Parag; Shukla, Vinay J.; Ravishankar, B.

2011-01-01

35

Human engineered heart tissue as a versatile tool in basic research and preclinical toxicology.  

PubMed

Human embryonic stem cell (hESC) progenies hold great promise as surrogates for human primary cells, particularly if the latter are not available as in the case of cardiomyocytes. However, high content experimental platforms are lacking that allow the function of hESC-derived cardiomyocytes to be studied under relatively physiological and standardized conditions. Here we describe a simple and robust protocol for the generation of fibrin-based human engineered heart tissue (hEHT) in a 24-well format using an unselected population of differentiated human embryonic stem cells containing 30-40% ?-actinin-positive cardiac myocytes. Human EHTs started to show coherent contractions 5-10 days after casting, reached regular (mean 0.5 Hz) and strong (mean 100 µN) contractions for up to 8 weeks. They displayed a dense network of longitudinally oriented, interconnected and cross-striated cardiomyocytes. Spontaneous hEHT contractions were analyzed by automated video-optical recording and showed chronotropic responses to calcium and the ?-adrenergic agonist isoprenaline. The proarrhythmic compounds E-4031, quinidine, procainamide, cisapride, and sertindole exerted robust, concentration-dependent and reversible decreases in relaxation velocity and irregular beating at concentrations that recapitulate findings in hERG channel assays. In conclusion this study establishes hEHT as a simple in vitro model for heart research. PMID:22028871

Schaaf, Sebastian; Shibamiya, Aya; Mewe, Marco; Eder, Alexandra; Stöhr, Andrea; Hirt, Marc N; Rau, Thomas; Zimmermann, Wolfram-Hubertus; Conradi, Lenard; Eschenhagen, Thomas; Hansen, Arne

2011-10-20

36

Toxicogenomics in drug discovery: from preclinical studies to clinical trials  

Microsoft Academic Search

Gene expression analysis applied to toxicology studies, also referred to as toxicogenomics, is rapidly being embraced by the pharmaceutical industry as a useful tool to identify safer drugs in a quicker, more cost-effective manner. Studies have already demonstrated the benefits of applying gene expression profiling towards drug safety evaluation, both for identifying mechanisms underlying toxicity, as well as for providing

Yi Yang; Eric A. G. Blomme; Jeffrey F. Waring

2004-01-01

37

Toxicologic Studies for Investigational New Drugs.  

National Technical Information Service (NTIS)

The general purpose of this program was to provide preclinical animal safety data on candidate antiparasitic test materials. The testing provided acute and subacute toxicity data to meet requirements of the Food and Drug Administration and, specifically, ...

F. E. Reno R. H. Cox J. A. Trutter R. W. Voelker

1984-01-01

38

Drug-eluting stents in preclinical studies: updated consensus recommendations for preclinical evaluation.  

PubMed

Coronary drug-eluting stents are commonplace in clinical practice with acceptable safety and efficacy. Preclinical evaluation of novel drug-eluting stent technologies has great importance for understanding safety and possibly efficacy of these technologies, and well-defined preclinical testing methods clearly benefit multiple communities within the developmental, testing, and clinical evaluation chain. An earlier consensus publication enjoyed widespread adoption but is in need of updating. This publication is an update, presenting an integrated view for testing drug-eluting technologies in preclinical models, including novel devices such as bioabsorbable coatings, totally bioabsorbable stents, bifurcation stents, and stent-free balloon-based drug delivery. This consensus document was produced by preclinical and translational scientists and investigators engaged in interventional technology community. The United States Food and Drug Administration (USFDA) recently issued a Draft Guidance for Industry Document for Drug-Eluting Stents. This expert consensus document is consistent with the Food and Drug Administration guidance. The dynamic nature of this field mandates future modifications and additions that will be added over time. PMID:20031669

Schwartz, Robert S; Edelman, Elazer; Virmani, Renu; Carter, Andrew; Granada, Juan F; Kaluza, Greg L; Chronos, Nicolas A F; Robinson, Keith A; Waksman, Ron; Weinberger, Judah; Wilson, Gregory J; Wilensky, Robert L

2008-10-01

39

Drug-Eluting Stents in Preclinical Studies Updated Consensus Recommendations for Preclinical Evaluation  

PubMed Central

Coronary drug-eluting stents are commonplace in clinical practice with acceptable safety and efficacy. Preclinical evaluation of novel drug-eluting stent technologies has great importance for understanding safety and possibly efficacy of these technologies, and well-defined preclinical testing methods clearly benefit multiple communities within the developmental, testing, and clinical evaluation chain. An earlier consensus publication enjoyed widespread adoption but is in need of updating. This publication is an update, presenting an integrated view for testing drug-eluting technologies in preclinical models, including novel devices such as bioabsorbable coatings, totally bioabsorbable stents, bifurcation stents, and stent-free balloon-based drug delivery. This consensus document was produced by preclinical and translational scientists and investigators engaged in interventional technology community. The United States Food and Drug Administration (USFDA) recently issued a Draft Guidance for Industry Document for Drug-Eluting Stents. This expert consensus document is consistent with the Food and Drug Administration guidance. The dynamic nature of this field mandates future modifications and additions that will be added over time.

Schwartz, Robert S.; Edelman, Elazer; Virmani, Renu; Carter, Andrew; Granada, Juan F.; Kaluza, Greg L.; Chronos, Nicolas A.F.; Robinson, Keith A.; Waksman, Ron; Weinberger, Judah; Wilson, Gregory J.; Wilensky, Robert L.

2010-01-01

40

Providing toxicokinetic support for reproductive toxicology studies in pharmaceutical development.  

PubMed

A package of toxicokinetic and disposition studies is generally conducted in support of reproductive toxicology studies in the development of new drugs. The content of the package often varies between companies and sometimes either insufficient data or inappropriate/over-interpreted data are presented. This paper was written to aid investigators in the design of toxicokinetic and disposition studies in support of reproductive toxicology. It offers: (1) an overview on the regulatory guidelines for toxicokinetics, (2) methods for the derivation of toxicokinetic parameters, (3) suggestions on general toxicokinetic study design, (4) suggestions on the specific design of toxicokinetic support for reproductive toxicology studies, and (5) an overview of species differences in placental transfer and the applicability (or otherwise) of transfer studies in drug development. Toxicokinetic and drug disposition studies should be carefully designed in order to gather relevant information, and consideration should be given to the usefulness of any data before embarking on a series of supporting or routine experiments. PMID:11693177

Schwartz, S

2001-09-01

41

[Preclinical study of anxiolytic activity and safety of Racium phytomedicine].  

PubMed

Results of a preclinical study of the anxiolytic activity and safety of original Racium phytomedicine are presented. The preparation possessed high anxiolytic activity, exhibits a wide range of therapeutic effects, produces no lethality in male and female rats and mice upon single intragastric and intraperitoneal introduction in doses up to 5 g/kg (VI class of toxicity according to OECD), induces no pathologic effects upon prolonged (120 days) administration in these rodents, and has no local irritant and/or allergen action. PMID:23012991

Kravchenko, E V; Nasek, V M; Ponteleeva, I V; Mazhar, M V; Sholomitskaia, E Iu; Zhukova, I A; San'ko, E V; Veselukha, O V; Nekhai, A S; Shafranovskaia, E V; Zhebrakova, I V

2012-01-01

42

Nonclinical toxicology study of recombinant-plasmid DNA anti-rabies vaccines  

Microsoft Academic Search

The absence of standard guidelines from National and International regulatory agencies for the safety evaluation of biotechnology products challenges the ingenuity of toxicologists. At present, the development of standard pre-clinical toxicology protocols for such products is on an individual case basis. The present investigation is an attempt to evaluate the safety profile of the first indigenously developed DNA based anti-rabies

P. Uday Kumar; B. Dinesh Kumar; V. V. Annapurna; T. Prasanna Krishna; S. Kalyanasundaram; P. Suresh; N. Harishankar; V. Jagadeesan; S. Hariharan; A. Nadamuni Naidu; Kamala Krishnaswamy; P. N. Rangarajan; V. A. Srinivasan; G. S. Reddy; B. Sesikeran

2006-01-01

43

Summary of Chemically Induced Pulmonary Lesions in the National Toxicology Program (NTP) Toxicology and Carcinogenesis Studies  

PubMed Central

The lung is the second most common target site of neoplasia of chemicals tested by the National Toxicology Program (NTP). Of all peer-reviewed NTP studies to date (N = 545), a total of sixty-four chemicals in sixty-six reports produced significant site-specific neoplasia in the lungs of rats and/or mice. Of the studies associated with lung tumor induction, approximately 35% were inhalation and 35% were gavage studies, with dosed-feed, dosed-water, topical, intraperitoneal, or in utero routes of chemical administration accounting for 18%, 6%, 3%, 1%, and 1% of the studies, respectively. The most commonly induced lung tumors were alveolar/bronchiolar (A/B) adenoma and/or carcinoma for both species. The most frequently observed nonneoplastic lesions included hyperplasia and inflammation in both species. The liver was the most common primary site of origin of metastatic lesions to the lungs of mice; however, skin was most often the primary site of origin of metastatic lesions to the lungs of rats. In summary, A/B adenoma and carcinoma were the most frequently diagnosed chemically induced tumors in the lungs of both rats and mice in the NTP toxicology and carcinogenesis bioassays, and hyperplasia and inflammation were the most common nonneoplastic changes observed.

Dixon, Darlene; Herbert, Ronald A.; Kissling, Grace E.; Brix, Amy E.; Miller, Rodney A.; Maronpot, Robert R.

2009-01-01

44

Behaviour-Toxicological Studies in Rats Exposed to Cadmium.  

National Technical Information Service (NTIS)

Studies were carried out on a behaviour-toxicological animal model in order to find out whether Cd may induce a minimal cerebral dysfunction and whether this effect outlasts prenatal and neonatal exposure. For this purpose, pregnant Wistar rats were given...

F. Wurms

1979-01-01

45

Microbiological and toxicological studies on cellulose generated from agricultural wastes  

Microsoft Academic Search

A pharmaceutical excipient is required to meet certain minimum standards for use in the manufacture of dosage forms. In this study, two of such requirements, microbiological and toxicological suitability, was investigated in respect of cellulose powder derived from an agricultural waste, maize cob. Microbial count data were obtained by inoculating a suspension of the cellulose into various types of agar.

Raymon I. Ozolua; Eric K. I. Omogbai; John O. Akerele; Augustine O. Okhamafe

46

Resveratrol: A review of preclinical studies for human cancer prevention  

SciTech Connect

The search for novel and effective cancer chemopreventive agents has led to the identification of various naturally occurring compounds one of which is resveratrol (trans-3,4',5-trihydroxystilbene), a phytoalexin derived from the skin of grapes and other fruits. Resveratrol is known to have potent anti-inflammatory and antioxidant effects and to inhibit platelet aggregation and the growth of a variety of cancer cells. Its potential chemopreventive and chemotherapeutic activities have been demonstrated in all three stages of carcinogenesis (initiation, promotion, and progression), in both chemically and UVB-induced skin carcinogenesis in mice, as well as in various murine models of human cancers. Evidence from numerous in vitro and in vivo studies has confirmed its ability to modulate various targets and signaling pathways. This review discusses the current preclinical and mechanistic data available and assesses resveratrol's anticancer effects to support its potential as an anticancer agent in human populations.

Athar, Mohammad; Back, Jung Ho; Tang Xiuwei [Department of Dermatology, College of Physicians and Surgeons, Columbia University, 630 West 168th Street VC15-204, New York, NY 10032 (United States); Kim, Kwang Ho [Department of Dermatology, Hallym University College of Medicine (Korea, Republic of); Kopelovich, Levy [Division of Cancer Prevention, National Cancer Institute, Bethesda, MD 20892 (United States); Bickers, David R. [Department of Dermatology, College of Physicians and Surgeons, Columbia University, 630 West 168th Street VC15-204, New York, NY 10032 (United States); Kim, Arianna L. [Department of Dermatology, College of Physicians and Surgeons, Columbia University, 630 West 168th Street VC15-204, New York, NY 10032 (United States)], E-mail: ak309@columbia.edu

2007-11-01

47

An algorithm for evaluating potential tissue drug distribution in toxicology studies from readily available pharmacokinetic parameters.  

PubMed

Having an understanding of drug tissue accumulation can be informative in the assessment of target organ toxicities; however, obtaining tissue drug levels from toxicology studies by bioanalytical methods is labor-intensive and infrequently performed. Additionally, there are no described methods for predicting tissue drug distribution for the experimental conditions in toxicology studies, which typically include non-steady-state conditions and very high exposures that may saturate several processes. The aim was the development of an algorithm to provide semiquantitative and quantitative estimates of tissue-to-plasma concentration ratios (Kp ) for several tissues from readily available parameters of pharmacokinetics (PK) such as volume of distribution (Vd ) and clearance of each drug, without performing tissue measurement in vivo. The computational approach is specific for the oral route of administration and non-steady-state conditions and was applied for a dataset of 29 Genentech small molecules such as neutral compounds as well as weak and strong organic bases. The maximum success rate in predicting Kp values within 2.5-fold error of observed Kp values was 82% at low doses (<100 mg/kg) in preclinical species. Prediction accuracy was relatively lower with saturation at high doses (?100 mg/kg); however, an approach to perform low-to-high dose extrapolations of Kp values was presented and applied successfully in most cases. An approach for the interspecies scaling was also applied successfully. Finally, the proposed algorithm was used in a case study and successfully predicted differential tissue distribution of two small-molecule MET kinase inhibitors, which had different toxicity profiles in mice. This newly developed algorithm can be used to predict the partition coefficients Kp for small molecules in toxicology studies, which can be leveraged to optimize the PK drivers of tissue distribution in an attempt to decrease drug tissue level, and improve safety margins. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:3816-3829, 2013. PMID:23878104

Poulin, Patrick; Dambach, Donna M; Hartley, Dylan H; Ford, Kevin; Theil, Frank-Peter; Harstad, Eric; Halladay, Jason; Choo, Edna; Boggs, Jason; Liederer, Bianca M; Dean, Brian; Diaz, Dolores

2013-07-22

48

The Primate Preclinical Test Center for Immune Suppression Study.  

National Technical Information Service (NTIS)

During the period January 27, 1969 to January 31, 1970, 101 (70*) different antilymphocyte sera (ALS) were received from various transplant centers and collaborators throughout the United States at the 'Primate Preclinical Test Center for Immune Suppressi...

C. C. Darrow G. S. LaFontaine

1970-01-01

49

Novel technology to prepare oral formulations for preclinical safety studies.  

PubMed

A novel method to prepare oral formulations, normally suspended dosage form, for preclinical safety studies in animals has been developed using a rotation/revolution mixer. Small hard balls made of zirconia were added to the mixing process to evaluate effectiveness in making a high quality suspension. The driving with balls loaded in the cylindrical container (vessel) of the mixer was quite efficient in dispersing and milling the particles of the active pharmaceutical ingredient (API) in an aqueous medium. The API powder and a small amount of oral aqueous medium (vehicle) were successfully mixed by the spinning motion of the balls in the vessel as though the paste-like suspension was kneaded with a mortar and pestle. It was found that the milled suspension with the mean size of 10-20microm could be prepared, in addition finer milling of less than 10microm could be achieved by selecting the material of vessel. Optimum driving conditions including mixing time, size and quantity of balls, and the standard operational procedure was established using compounds varying in physicochemical properties. The particle size and quantitative analysis by HPLC showed that the resultant suspension was well-milled and highly homogeneous with the nearly intended concentration of API. The proposed method established by this experiment could be applied to the actual safety studies in the real preparation scale of oral suspension. PMID:17942253

Niwa, Toshiyuki; Hashimoto, Naofumi

2007-08-24

50

Preclinical toxicity studies with two thymopoietin-like peptides.  

PubMed

Differentiation of T-lymphocytes is regulated by thymopoietin, a 49 amino acid polypeptide chain. The site of immunological activity is in the 32-36 (Arg-Lys-Asp-Val-Tyr) fragment. This pentapeptide can be reduced to a tetrapeptide (RGH-0206: Arg-Lys-Asp-Val) and further to a tripeptide (RGH-0205: Arg-Lys-Asp) which still retains immunological activity. To prepare Phase I and II clinical trials preclinical toxicity studies were duly performed. Mice, rats and dogs tolerated a single 1000 mg/kg dose i.v. without any symptom. In a 14-day i.v. test on Lati:Han:WISTAR rats daily doses of 10,25, 62.5, 150, 400 and 1000 mg/kg of either test compound were tolerated without symptom or damage. In a 28-day i.v. toxicity test on Wobe:BEAGLE dogs given daily doses of 6, 20 and 60 mg/kg of either test compound, no adverse reaction occurred. The low toxicity of both RGH-0205 and RGH-0206 are probably attributable to their short half-life, as half-life of the pentapeptide fraction is less than 30 sec in humans. It was concluded that the planned clinical dose of 1 mg/kg i.v. was safe for both peptides for short-term administration. PMID:3868381

Iván, E; Bodrogligeti, I; Juhász-Nagy, A; Német, L; Cholnoky, E

1985-01-01

51

Protective efficacy of Modified Vaccinia virus Ankara in preclinical studies.  

PubMed

Modified Vaccinia virus Ankara (MVA) is a tissue culture-derived, highly attenuated strain of vaccinia virus (VACV) exhibiting characteristic defective replication in cells from mammalian hosts. In the 1960s MVA was originally generated as a candidate virus for safer vaccination against smallpox. Now, MVA is widely used in experimental vaccine development targeting important infectious diseases and cancer. Versatile technologies for genetic engineering, large-scale production, and quality control facilitate R&D of recombinant and non-recombinant MVA vaccines matching today's requirements for new biomedical products. Such vaccines are attractive candidates for delivering antigens from pathogens against which no, or no effective vaccine is available, including emerging infections caused by highly pathogenic influenza viruses, chikungunya virus, West Nile virus or zoonotic orthopoxviruses. Other directions are seeking valuable vaccines against highly complex diseases such as AIDS, malaria, and tuberculosis. Here, we highlight examples of MVA candidate vaccines against infectious diseases, and review the efforts made to assess both the efficacy of vaccination and immune correlates of protection in preclinical studies. PMID:23523402

Volz, Asisa; Sutter, Gerd

2013-03-21

52

Quetiapine: preclinical studies, pharmacokinetics, drug interactions, and dosing.  

PubMed

Quetiapine is a novel dibenzothiazepine atypical antipsychotic. Quetiapine shows affinity for various neurotransmitter receptors including serotonin, dopamine, histamine, and adrenergic receptors and has binding characteristics at the dopamine-2 receptor similar to those of clozapine. In animal models, the drug has a preclinical profile suggestive of antipsychotic activity with a reduced tendency to cause extrapyramidal symptoms (EPS) and sustained prolactin elevation. For example, quetiapine alters neurotensin neurotransmission and c-fos expression in limbic but not motor brain regions. The drug also demonstrates clozapine-like activity in a range of behavioral and biochemical tests and may possess neuroprotective properties. In humans, quetiapine exhibits linear pharmacokinetics with a mean terminal half-life of 7 hours. The primary route of elimination of quetiapine is through hepatic metabolism. Although not affected by smoking, alterations in quetiapine disposition due to age or hepatic impairment are manageable by appropriate dosage reduction. The optimal dosing range for quetiapine is 150 to 750 mg/day, and recent results suggest that once-daily dosing may be suitable for some patients. Finally, imaging studies with positron emission tomography confirm significant differences between quetiapine and typical antipsychotics that may be indicative of their differences in mechanism of action and propensity for producing EPS. PMID:12562141

Nemeroff, Charles B; Kinkead, Becky; Goldstein, Jeffrey

2002-01-01

53

Preclinical studies of [ 99mTc]DTPA-mannosyl-dextran? ? ? Supported in part by National Cancer Institute Grant CA72751 and University of California Breast Cancer Research Program Grants 2RB0018 and 4IB0051  

Microsoft Academic Search

We report the preclinical testing of a synthetic receptor-binding macromolecule, [99mTc]DTPA-mannosyl-dextran (36 kDa, 8 DTPA and 55 mannosyl units per dextran, KD = 0.12 nM), for sentinel node detection. Nonclinical safety studies included cardiac pharmacology safety studies, acute toxicology and pathology studies at 50 and 500 times the scaled human dose in both rats and rabbits after foot pad administration,

Carl K Hoh; Anne M Wallace; David R Vera

2003-01-01

54

Isotopic study of the toxicology of oxidants  

SciTech Connect

Several aspects of the fate of /sup 18/O/sub 3/ in the respiratory system were examined. The distribution of ozone-derived oxygen in the nasopharynx and trachea was found to be related to the velocity profile of inspired air in these airways. In mice exposed to 1 ppm /sup 18/O/sub 3/, the amount of ozone-derived oxygen retained in the lungs increased linearly with time of exposure, at a rate of approximately 100 picomoles per minute. Clearance of the isotopic label exhibited biphasic kinetics, where 80% of the initial dose was cleared with a half-life of 2.2 h and the remainder was cleared with a half-life of 70 h. The macromolecular component of the lung contained approximately 80% of the label. Free radical-induced oxidation results in the incorporation of oxygen from O/sub 2/ into molecular constituents of the cell. To study reactions of this type, autoxidation of hepatic tissue in rats was induced by interperitoneal injection of carbon tetrachloride. Autoxidation resulted in a large increase in the oxygen-18 content of liver tissue in animals breathing air containing /sup 18/O/sub 2/. The amount of excess oxygen-18 retained in the liver was related to cytochrome P-450 activity. Appreciable amounts of the isotopic label were also detected in the macromolecular fraction from liver tissue.

Santrock, J.

1985-01-01

55

Nonclinical toxicology study of recombinant-plasmid DNA anti-rabies vaccines.  

PubMed

The absence of standard guidelines from National and International regulatory agencies for the safety evaluation of biotechnology products challenges the ingenuity of toxicologists. At present, the development of standard pre-clinical toxicology protocols for such products is on an individual case basis. The present investigation is an attempt to evaluate the safety profile of the first indigenously developed DNA based anti-rabies vaccine in India. The test compounds were DNA rabies vaccine [DRV (100 microg)] and combination rabies vaccine (CRV (100 microg DRV and 1/50 dose of cell culture vaccine)), intended for clinical use by intramuscular route on 1, 7, 14 and 28 day. As per the regular mandatory requirements, the study has been designed to undertake acute (single dose--10 days), sub-chronic (repeat dose--28 days) and chronic (intended clinical dose--120 days) toxicity tests using three dose levels viz. therapeutic, average (2 x therapeutic dose) and highest dose (10 x therapeutic dose) exposure in Swiss Albino mice. The selection of the rodent model viz. Swiss Albino mice is based on affinity and rapid higher antibody response during the efficacy studies. Apart from physical, physiological, clinical, hematological and histopathology profiles of all target organs, the tier-I immunotoxicity parameters have also been monitored. There were no observational adverse effects even at levels of 10x therapeutic dose administration of DRV and CRV. The procedure also emphasizes on the designing of protocols for the products developed by recombinant technique. PMID:16448727

Kumar, P Uday; Kumar, B Dinesh; Annapurna, V V; Krishna, T Prasanna; Kalyanasundaram, S; Suresh, P; Harishankar, N; Jagadeesan, V; Hariharan, S; Naidu, A Nadamuni; Krishnaswamy, Kamala; Rangarajan, P N; Srinivasan, V A; Reddy, G S; Sesikeran, B

2006-01-13

56

Intravital microscopy as a tool to study drug delivery in preclinical studies  

PubMed Central

The technical developments in the field of non-linear microscopy have made intravital microscopy one of the most successful techniques for studying physiological and pathological processes in live animals. Intravital microscopy has been utilized to address many biological questions in basic research and is now a fundamental tool for preclinical studies, with an enormous potential for clinical applications. The ability to dynamically image cellular and subcellular structures combined with the possibility to perform longitudinal studies have empowered investigators to use this discipline to study the mechanisms of action of therapeutic agents and assess the efficacy on their targets in vivo. The goal of this review is to provide a general overview of the recent advances in intravital microscopy and to discuss some of its applications in preclinical studies.

Amornphimoltham, Panomwat; Masedunskas, Andrius; Weigert, Roberto

2010-01-01

57

Intravital microscopy as a tool to study drug delivery in preclinical studies.  

PubMed

The technical developments in the field of non-linear microscopy have made intravital microscopy one of the most successful techniques for studying physiological and pathological processes in live animals. Intravital microscopy has been utilized to address many biological questions in basic research and is now a fundamental tool for preclinical studies, with an enormous potential for clinical applications. The ability to dynamically image cellular and subcellular structures combined with the possibility to perform longitudinal studies have empowered investigators to use this discipline to study the mechanisms of action of therapeutic agents and assess the efficacy on their targets in vivo. The goal of this review is to provide a general overview of the recent advances in intravital microscopy and to discuss some of its applications in preclinical studies. PMID:20933026

Amornphimoltham, Panomwat; Masedunskas, Andrius; Weigert, Roberto

2010-10-07

58

Preclinical evaluation of the toxicological effects of a novel constrained ethyl modified antisense compound targeting signal transducer and activator of transcription 3 in mice and cynomolgus monkeys.  

PubMed

ISIS 481464 is a constrained ethyl (cEt) modified phosphorothioate antisense oligonucleotide (ASO) targeting signal transducer and activator of transcription 3 (STAT3) studied in mice and monkey to support oncology clinical trials. Six-week toxicology studies were performed in mice and cynomolgus monkey (up to 70 and 30 mg/kg/week respectively). Reduction in STAT3 protein up to 90% of control was observed in monkey. Cynomolgus monkey was considered the most relevant species to human with respect to pharmacokinetic properties, but mice are useful in their relative sensitivity to the potential proinflammatory and hepatic effects of oligonucleotides. In monkeys, there was no impact on organ function at doses up to 30 mg/kg/week for 6 weeks. Minimal to slight proximal tubular epithelial cell degeneration and regeneration within the kidney was observed, which had no impact on renal function and showed reversibility at the end of the treatment-free period. Additionally, mild and transient activated partial thromboplastin time elevations and mild increases in complement Bb were observed at the higher doses by intravenous dosing only. In mice, the alterations at 70 mg/kg/week included spleen weight increase up to 1.4-fold relative to control, increases in alanine aminotransferase and aspartate aminotransferase up to 1.8-fold over control, interleukin-10 increases up to 3.7-fold, and monocyte chemoattractant protein-1 increase up to 1.9-fold over control. No significant clinical pathology or histopathology changes were seen in mice at 20 mg/kg/week or less. The toxicity profile of ISIS 481464 is consistent with effects observed with phosphorothioate ASOs containing 2'-O-methoxyethylribose modifications instead of cEt. PMID:23692080

Burel, Sebastien A; Han, So-Ri; Lee, Hong-Soo; Norris, Daniel A; Lee, Byoung-Seok; Machemer, Todd; Park, Shin-Young; Zhou, Tianyuan; He, Guobin; Kim, Youngsoo; MacLeod, A Robert; Monia, Brett P; Lio, Shirley; Kim, Tae-Won; Henry, Scott P

2013-06-01

59

Translation of stem cell research: points to consider in designing preclinical animal studies.  

PubMed

Stem cell-based therapies hold tremendous promise for the treatment of serious diseases and injuries. Although hematopoietic stem cell transplantation is routinely used as part of the treatment regime for some malignancies and genetic diseases, most stem cell-based therapeutic products are investigational and still require preclinical and clinical studies to support their many novel therapeutic uses. Because of the multiple sources of stem cells, the plethora of potential applications, and the novel mechanism of action of stem cell-based therapies, there is no single set of universal guidance documents that can be used to inform the preclinical development path for these therapeutics. Specific technical issues relating to the transplantation of human cells in animals, new delivery procedures, and laborious methods to characterize transplanted cells can present further challenges in the design and execution of preclinical animal studies for stem cell-based therapeutic products. In this article, we outline important parameters to guide the design of preclinical studies for stem cell-based therapeutics. In addition, we review the types of preclinical studies that should be considered depending on the nature and specific use of the intended stem cell therapeutic product. Finally, we describe important considerations in the design and execution of specific studies to monitor the efficacy, toxicity, biodistribution, and tumorigenicity of stem cell-based therapeutics. PMID:23197814

Frey-Vasconcells, Joyce; Whittlesey, Kevin J; Baum, Elona; Feigal, Ellen G

2012-02-06

60

Towards environmental construct validity in animal models of CNS disorders: optimizing translation of preclinical studies.  

PubMed

There is an enormous demand for new therapeutic interventions for a range of major disorders. The majority of clinical trials in recent years have been unsuccessful despite highly promising preclinical data. Therefore, an urgent issue confronting both the academic and commercial medical research sectors is how to optimize translation of preclinical studies. The vast majority of preclinical studies are currently performed using laboratory mice and rats. We will discuss the various opportunities for optimization of animal models of CNS disorders. One limitation of current approaches is that most studies are conducted on sedentary, unstimulated animals with unlimited access to food in the home cage, thus leading to metabolic and physiological compromise. Environmental enrichment, which enhances sensory stimulation, cognitive activity and physical exercise, has been demonstrated to induce dramatic effects on brain and behavior in both wild-type and genetically modified rodent models, relative to standard-housed littermate controls. Environmental enrichment also exerts beneficial effects outside the CNS, such as a reduction in excess body fat. We propose that therapeutic interventions which are found to show promise in standard-housed preclinical models should be subsequently tested under conditions of greater environmental enrichment to identify therapeutics which continue to show efficacy in housing contexts of superior 'environmental construct validity'. Other possible approaches to optimize the quality, validity and reporting of preclinical studies in animal models are also discussed. PMID:23574171

Burrows, Emma L; Hannan, Anthony J

2013-08-01

61

Personal reflections on 50 years of study of benzene toxicology.  

PubMed Central

The metabolism of benzene is reviewed, and the objectives of a quantitative balance study begun in 1945 are outlined; problems of toxicology and metabolism research of some 50 years ago are considered. The quantitative metabolism of 14C-benzene in the rabbit is annotated and compared with that of unlabeled benzene quantified by nonisotopic methods. The anomalies of phenylmercapturic acid and trans-trans-muconic acid as metabolites of benzene are examined in detail by isotopic and nonisotopic methods; these compounds are true but minor metabolites of benzene. Oxygen radicals are involved in both the metabolism of benzene and its toxicity; the roles of CYP2E1, the redox cycling of quinone metabolites, glutathione oxidation, and oxidative stress in the unique radiomimetic, hematopoietic toxicity of benzene are discussed. Differences between the toxicity of benzene and the halobenzenes are related to fundamental differences in their electronic structures and to the consequent pathways of metabolic activation and detoxication.

Parke, D V

1996-01-01

62

Cassava starch fermentation wastewater: characterization and preliminary toxicological studies.  

PubMed

Cassava starch fermentation wastewater is an industrial residue composed mainly of lactic acid bacteria with predominance of the genera Lactobacillus, and organic acids. To evaluate the safety of this residue for possible production of probiotic beverages, acute in mice and sub-chronic (28-day repeated dose) toxicity studies in rats were carried. The administration of a single dose of 5 g/kg/body weight did not produce mortality in mice. Rats treated with water containing 0 (control), 25%, 50%, and 100% of the residue for 28 days, did not present alterations in behaviour or in food and water consumption. There were no treatment-related changes of toxicological significance in the relative weight of the organs neither in the haematological nor in the biochemical parameters. Histopathologic alterations observed in the small intestine did not seem to be associated with the treatment. PMID:17637494

Avancini, S R P; Faccin, G L; Vieira, M A; Rovaris, A A; Podestá, R; Tramonte, R; de Souza, N M A; Amante, E R

2007-06-13

63

Environmental Toxicology  

NASA Astrophysics Data System (ADS)

Environmental Toxicology is a comprehensive introductory textbook dealing with most aspects of the subject, from the molecular to the ecosystem level. Early chapters deal with basic to advanced concepts, methods and approaches. The next discusses the environmental toxicology of individual or groups of substances. The third part addresses complex issues, in which many of the concepts, approaches and substances covered in earlier parts are incorporated. The fourth part includes chapters on risk assessment, rehabilitation and regulatory toxicology. The book concludes with a summary of present and future areas of emphasis. Each chapter contains a comprehensive list of references and further reading, case studies from different jurisdictions, and student exercises.

Wright, David A.; Welbourn, Pamela

2002-03-01

64

Preclinical Toxicologic Studies of Hexamethylmelamine in Beagle Dogs and CDF1 Mice.  

National Technical Information Service (NTIS)

Beagle dogs were treated intravenously with hexamethylmelamine in a single and multiple dose regimen. Major clinical signs observed during and after treatment were hyperexcitability, tetanic seizures, excessive salivation, urination, defecation, paresis, ...

D. C. Thake D. L. Metcalf A. M. Guarino T. E. Gram R. Folk

1978-01-01

65

ORAL TOXICOLOGY STUDIES WITH XYLENE ISOMERS AND MIXED XYLENES  

EPA Science Inventory

Xylene isomers and mixed xylenes were administered to male and female Sprague-Dawley rats to evaluate their effects on standard toxicological parameters rnhich included body and organ weights, hematology, serum chemistries, urinalysis and histopathological examination. n the init...

66

Behavioral Toxicological Studies of Pesticides in Laboratory Rats.  

National Technical Information Service (NTIS)

Behavioral testing procedures are still relatively new to the field of toxicology, but their use is rapidly growing. One of the principal reasons for their increasing popularity, and one which particularly bears on the Army's occupational health and safet...

P. J. Kurtz

1976-01-01

67

Anticancer activity of tolfenamic acid in medulloblastoma: a preclinical study.  

PubMed

Medulloblastoma (MB) is the most common malignancy in children arising in the brain. Morbidities associated with intensive therapy are serious concerns in treating MB. Our aim was to identify novel targets and agents with less toxicity for treating MB. Specificity protein 1 (Sp1) transcription factor regulates several genes involved in cell proliferation and cell survival including survivin, an inhibitor of apoptosis protein. We previously showed that tolfenamic acid (TA), a nonsteroidal anti-inflammatory drug, inhibits neuroblastoma cell growth by targeting Sp1. We investigated the anticancer activity of TA using human MB cell lines and a mouse xenograft model. DAOY and D283 cells were treated with vehicle (dimethyl sulfoxide) or TA (5-50 ?g/ml), and cell viability was measured at 1-3 days posttreatment. TA inhibited MB cell growth in a time- and dose-dependent manner. MB cells were treated with vehicle or TA (10 ?g/ml), and the effect on cell apoptosis was measured. Apoptosis was analyzed by flow cytometry (annexin V staining), and caspase 3/7 activity was determined using Caspase-Glo kit. The expression of Sp1, cleaved poly(ADP-ribose) polymerase (c-PARP), and survivin was determined by Western blot analysis. TA inhibited the expression of Sp1 and survivin and upregulated c-PARP. Athymic nude mice were subcutaneously injected with D283 cells and treated with TA (50 mg/kg, three times per week) for 4 weeks. TA caused a decrease of ~40 % in tumor weight and volume. The tumor growth inhibition was accompanied by a decrease in Sp1 and survivin expression in tumor tissue. These preclinical data demonstrate that TA acts as an anticancer agent in MB potentially targeting Sp1 and survivin. PMID:23686785

Eslin, Don; Lee, Chris; Sankpal, Umesh T; Maliakal, Pius; Sutphin, Robert M; Abraham, Liz; Basha, Riyaz

2013-05-18

68

Natural substances and Alzheimer's disease: From preclinical studies to evidence based medicine  

Microsoft Academic Search

Over the last 10years, the potential therapeutic effects of nutraceuticals to prevent or delay Alzheimer's disease were proposed. Among dietary antioxidants curcumin, Ginkgo biloba and carnitines were extensively studied for their neuroprotective effects. The rationale for this alternative therapeutic approach was based on several preclinical studies which suggested the neuroprotective effects for curcumin, Ginkgo biloba and acetyl-l-carnitine due to either

Cesare Mancuso; Raffaella Siciliano; Eugenio Barone; Paolo Preziosi

69

Manpower Development in Toxicology. EURO Reports and Studies, No. 9.  

ERIC Educational Resources Information Center

This report addresses the widely held view that currently available literature in toxicology is inadequate in that there is a need to identify manpower deficiencies in this field and to suggest means to correct these deficiencies. It contains a list of specific recommendations including the organization of a working group, sponsored by the World…

World Health Organization, Copenhagen (Denmark). Regional Office for Europe.

70

Manpower Development in Toxicology. EURO Reports and Studies, No. 9.  

ERIC Educational Resources Information Center

|This report addresses the widely held view that currently available literature in toxicology is inadequate in that there is a need to identify manpower deficiencies in this field and to suggest means to correct these deficiencies. It contains a list of specific recommendations including the organization of a working group, sponsored by the World…

World Health Organization, Copenhagen (Denmark). Regional Office for Europe.

71

In vitro preclinical lead optimisation technologies (PLOTs) in pharmaceutical development.  

PubMed

The explosion of genuine high throughput technologies has allowed large compound libraries to be screened with ever increasing biological specificity, exacerbating the problem of lead candidate selection for subsequent drug development. To avoid creating a bottleneck, compounds identified from the high throughput screens undergo lead optimisation, a medium-throughput screen which allows ranking in terms of their basic absorption, distribution, metabolism, excretion (ADME) and toxicological properties. The historical role of the preclinical scientist in the drug discovery/development continuum has been to perform ADME and toxicology studies, simply to support the regulatory submission of lead candidates. This situation is, however, changing with the development of preclinical lead optimisation technologies (Approaches to High Throughput Toxicity Screening, London, Atterwill et al., 1999) facilitating the selection of leading candidates, thereby bridging the gap between high throughput efficacy screens and traditional safety assessment programmes. PMID:12052652

Atterwill, Christopher K; Wing, Mark G

2002-02-28

72

A meta-analysis of marijuana, cocaine and opiate toxicology study findings among homicide victims.  

PubMed

ABSTRACT Aim To synthesize the results of marijuana, cocaine and opiate drug toxicology studies of homicide victims and examine variation in results across person and setting characteristics. Methods A meta-analysis of 18 independent studies identified from an extensive review of 239 published articles that met the inclusion criteria of reporting marijuana, cocaine and/or opiate toxicology test results for homicide victims. A total of 28 868 toxicology test results derived from 30 482 homicide victims across five countries were examined. Results On average, 6% of homicide victims tested positive for marijuana, 11% tested positive for cocaine, and 5% tested positive for opiates. The proportion of homicide victims testing positive for illicit drugs has increased over time. Age had a strong curvilinear relationship with toxicology test results, but gender differences were not apparent. Hispanic and African American homicide victims were more likely to test positive for cocaine; Caucasians were most likely to test positive for opiates. Cocaine use appeared to be related to increased risk of death from a firearm and was a greater risk factor for violent victimization in the United States than in Newfoundland and Scandinavia. Conclusion There are relatively few studies of illicit drug toxicology reports from homicide victims that allow for cross-cultural comparisons. This study provides a basis for comparing future local toxicology test results to estimates from existing research. PMID:19438418

Kuhns, Joseph B; Wilson, David B; Maguire, Edward R; Ainsworth, Stephanie A; Clodfelter, Tammatha A

2009-05-11

73

Spinal Cord Tolerance in the Age of Spinal Radiosurgery: Lessons from Pre-clinical Studies  

PubMed Central

Clinical implementation of spinal radiosurgery has increased rapidly in recent years but little is known regarding human spinal cord tolerance to single-fraction irradiation. In contrast, preclinical studies in single-fraction spinal cord tolerance have been ongoing since the 1970’s. The influences of field length, dose rate, inhomogeneous dose distributions and reirradiation have all been investigated. This review summarizes literature regarding single-fraction spinal cord tolerance in pre-clinical models with an emphasis on practical clinical significance. The outcomes of studies that incorporate uniform irradiation are surprisingly consistent among multiple small and large animal models. Extensive investigation of inhomogeneous dose distributions in the rat has demonstrated a significant dose-volume effect while preliminary results from one pig study are contradictory. Pre-clinical spinal cord dose-volume studies indicate that dose distribution is more critical than the volume irradiated suggesting that neither dose volume histogram analysis nor absolute volume constraints are effective in predicting complications. Reirradiation data is sparse, but results from guinea pig, rat and pig studies are consistent with the hypothesis that the spinal cord possesses a large capacity for repair. The mechanisms behind the phenomena observed in spinal cord studies are not readily explained and the ability of dose response models to predict outcomes is variable underscoring the need for further investigation. Animal studies provide insight into the phenomena and mechanisms of radiosensitivity but the true significance of animal studies can only be discovered through clinical trials.

Medin, Paul M.; Boike, Thomas P.

2010-01-01

74

Iron Deprivations Treatment of Breast Cancer: Pre-Clinical Studies.  

National Technical Information Service (NTIS)

Progress has been made in the study of iron deprivation as a potential treatment modality for breast cancer. Enhanced macrophage activation with an augmented acute phase response has been implicated as a source of potential treatment related toxicity. Def...

J. D. Kemp

1997-01-01

75

From Bench to Bedside: Lessons Learned in Translating Preclinical Studies in Cancer Drug Development  

PubMed Central

The development of targeted agents in oncology has rapidly expanded over the past 2 decades and has led to clinically significant improvements in the treatment of numerous cancers. Unfortunately, not all success at the bench in preclinical experiments has translated to success at the bedside. As preclinical studies shift toward defining proof of mechanism, patient selection, and rational drug combinations, it is critical to understand the lessons learned from prior translational studies to gain an understanding of prior drug development successes and failures. By learning from prior drug development, future translational studies will provide more clinically relevant data, and the underlying hope is that the clinical success rate will improve and the treatment of patients with ineffective targeted therapy will be limited.

2013-01-01

76

From bench to bedside: lessons learned in translating preclinical studies in cancer drug development.  

PubMed

The development of targeted agents in oncology has rapidly expanded over the past 2 decades and has led to clinically significant improvements in the treatment of numerous cancers. Unfortunately, not all success at the bench in preclinical experiments has translated to success at the bedside. As preclinical studies shift toward defining proof of mechanism, patient selection, and rational drug combinations, it is critical to understand the lessons learned from prior translational studies to gain an understanding of prior drug development successes and failures. By learning from prior drug development, future translational studies will provide more clinically relevant data, and the underlying hope is that the clinical success rate will improve and the treatment of patients with ineffective targeted therapy will be limited. PMID:24052618

Lieu, Christopher H; Tan, Aik-Choon; Leong, Stephen; Diamond, Jennifer R; Eckhardt, S Gail

2013-09-19

77

Therapeutic Applications of Incretin Mimetics for Metabolic Diseases: Preclinical Studies  

Technology Transfer Automated Retrieval System (TEKTRAN)

Exenatide (exendin-4) is an incretin mimetic peptide that shares several glucoregulatory actions with the endogenous incretin GLP-1. In addition to its actions on glucose control, exenatide produces effects to reduce food intake and body weight in all species studied. GLP-1 and exenatide have also b...

78

Preclinical Studies on the Anti-Migraine Drug, Sumatriptan  

Microsoft Academic Search

Sumatriptan is believed to constrict selectively the cranial vessels that are distended and inflamed during migraine. The action is mediated by activation of a 5-HT1 receptor subtype which has been shown in animals to be localized in cranial vessels. Further studies to elaborate sumatriptan’s precise clinical mode of action have focused on the human meningeal circulation and should lead to

P. P. A. Humphrey; W. Feniuk; A. S. Marriott; R. J. N. Tanner; M. R. Jackson; M. L. Tucker

1991-01-01

79

Robotic-assisted skull base surgery: preclinical study.  

PubMed

Abstract Objective and Study Design: To assess the feasibility of robotic-assisted skull base surgery, a preclincal cadaver study was conducted. Materials and Methods: The feasibility study was subdivided into three phases: Phase 1 (surgical corridor) entailed a review of the surgical access, Phase 2 (instrument configuration) entailed arrangements of the robotic instrument (da Vinci(®) Surgical System; Intuitive Surgical, Sunnyvale, CA) in relation to the surgical corridor and applied to a skull model, and Phase 3 was robotic-assisted skull base cadaver dissection. Results: Regarding the surgical corridor, the infratemporal area was accessed through a maxillary window, whereas the anterior skull base region was accessed through a combined single maxillary window and nasal corridor. Regarding instrument configuration, the camera was positioned above the two instrument arms, with both instrument arms angled at 30° to the camera axis with a flexed distal tip for the infratemporal skull base. For the anterior skull base, one of the robotic arms was inserted through the unilateral maxillary window, whereas the three-dimensional camera and the second arm were inserted through the nasal corridor. Regarding the robotic-assisted skull base cadaver dissection, we define the robotic set-up time in this study as the time required to move the robot into position, obtain adequate operative exposure, and place the robotic arms prior to the start of robotic dissection. The robotic set-up time for the anterior skull base dissection averaged 95 minutes, and that for pituitary resection was 61 minutes. The robotic set-up time for infratemporal dissection averaged 23 minutes. Operative time was 63.5 minutes. Robotic and endoscopic techniques can be combined during surgery. Conclusions: Robotic-assisted skull base surgery is feasible. The da Vinci instrument needs to be redesigned to be smaller and preferably with distal articulating tips, prior to clinical application of robotics to skull base surgery. PMID:24001158

Blanco, Ray Gervacio F; Boahene, Kofi

2013-09-01

80

Wireless Video Capsule Enteroscopy in Preclinical Studies: Methodical Design of Its Applicability in Experimental Pigs  

Microsoft Academic Search

The aim of this project was to develop a methodology to introduce wireless video capsule endoscopy in preclinical research.\\u000a Five mature female pigs (Sus scrofa domestica) were selected for the study. Capsule endoscopes (the EndoCapsule system; Olympus) were introduced into the duodenum endoscopically\\u000a in each of the animals. The life span of batteries (i.e., total time of endoscopy recording) was

Marcela Kopá?ová; Ilja Tachecí; Jaroslav Kv?tina; Jan Bureš; Martin Kuneš; Stanislav Špelda; V?ra Ty?ová; Zbyn?k Svoboda; Stanislav Rejchrt

2010-01-01

81

Pharmacology and Pharmacodynamics of Bevacizumab as Monotherapy or in Combination with Cytotoxic Therapy in Preclinical Studies  

Microsoft Academic Search

Preclinical models have examined the pharmacologic and pharmacodynamic activities of an anti-vascular endothelial growth factor (VEGF) humanized, monoclonal antibody, bevacizumab, and\\/or its murine equivalent A4.6.1. These studies found that single-agent therapy with bevacizumab\\/ A4.6.1 resulted in tumor growth inhibition of 20 different human tumor cell lines (13 tumor types) implanted into nude mice irrespective of the route of administration or

Hans-Peter Gerber; Napoleone Ferrara

2005-01-01

82

Interleukin-2 in bone marrow transplantation: preclinical studies.  

PubMed

Interleukin-2 (IL-2) promotes the generation and proliferation of killer cells in the peripheral blood and bone marrow (BM) both in vitro and in vivo. When employed in a syngeneic bone marrow transplantation (BMT) setting and followed by IL-2 therapy, murine BM cells activated with IL-2 in vitro (ABM) demonstrate potent graft-versus-leukemia (GVL) and anticytomegalovirus effects. ABM cells retain the capacity to reconstitute the hemopoietic system both in normal and leukemic mice. This therapy does not cause graft-versus-host disease (GVHD). Human ABM cells carry out purging of leukemia without loss of progenitor cell activity in vitro. The purging ability of ABM can be augmented by interleukin-1, interferon, and tumor necrosis factor. IL-2 therapy stimulates the veto suppressor cell activity of T cell-depleted BM, and has reduced GVHD and permitted engraftment of mismatched allogeneic BM in murine models. Future studies should determine the optimum treatment schedules with IL-2 for improving the GVL effect in autologous BMT, and for abolishing GVHD in allogeneic BMT settings. PMID:1326364

Charak, B S; Choudhary, G D; Tefft, M; Mazumder, A

1992-08-01

83

Aquatic toxicology  

Microsoft Academic Search

This paper briefly reviews the application of histopathology as aninstrument or endpoint in toxicity studies in fish. For long this has been applied rather occasionally in (regulatory) toxicology, and was mainly of interest in fundamental studies and limited carcinogenicity experiments. However, nowadays there are various incentives that ask for the application of pathology, such as field monitoring of pollution effects,

P. W Wester; L. T. M van der Ven; A. D Vethaak; G. C. M Grinwis; J. G Vos

2002-01-01

84

SOCIETY OF TOXICOLOGIC PATHOLOGY POSITION PAPER: BEST PRACTICES FOR REPORTING PATHOLOGY INTERPRETATIONS WITHIN GLP TOXICOLOGY STUDIES.  

EPA Science Inventory

The study pathologist provides specialized expertise to the interpretation of the toxicity and safety of pharmaceuticals, biological agents, human and animal food additives, environmental and industrial chemicals, and medical devices in animal studies. The study pathologist's fin...

85

Factors influencing the approaches to studying of preclinical and clinical students and postgraduate trainees  

PubMed Central

Background Students can be classified into three categories depending on their approaches to studying; namely, deep approach (DA), strategic approach (SA) and surface apathetic or superficial approach (SAA). The aim of this study was to identify factors affecting the approaches to studying among Sri Lankan medical undergraduates and post graduate trainees and to analyze the change in the pattern of study skills with time and experience. Method Pre-clinical and clinical students of the Faculty of Medicine, University of Colombo and postgraduate trainees in Surgery at the National Hospital of Sri Lanka were invited to complete the Approaches and Study Skills Inventory for Students (ASSIST) questionnaire. Results A total of 187 pre clinical (M: F = 96:91), 124 clinical (M: F = 61:63) and 53 post graduate trainees (M: F = 50:3) participated in the study. Approaches of male and female students were similar. SA was significantly affected by age among the preclinical students (p = 0.01), but not in other groups. Among pre-clinical students, males preferred a teacher who supported understanding (p = 0.04) but females preferred a passive transmission of information (p < 0.001). This, too, was not visible among other groups. A linear regression performed on group (batch), gender, island rank at GCE Advance Level (AL) examination, self appraisal score and the preference scores of type of teacher only managed to explain 35% or less of variance observed for each approach in individual groups. Conclusion Different factors affect the approach to studying in different groups but these explain only a small fraction of the variance observed.

2011-01-01

86

Accelerating drug discovery for Alzheimer's disease: best practices for preclinical animal studies  

PubMed Central

Animal models have contributed significantly to our understanding of the underlying biological mechanisms of Alzheimer's disease (AD). As a result, over 300 interventions have been investigated and reported to mitigate pathological phenotypes or improve behavior in AD animal models or both. To date, however, very few of these findings have resulted in target validation in humans or successful translation to disease-modifying therapies. Challenges in translating preclinical studies to clinical trials include the inability of animal models to recapitulate the human disease, variations in breeding and colony maintenance, lack of standards in design, conduct and analysis of animal trials, and publication bias due to under-reporting of negative results in the scientific literature. The quality of animal model research on novel therapeutics can be improved by bringing the rigor of human clinical trials to animal studies. Research communities in several disease areas have developed recommendations for the conduct and reporting of preclinical studies in order to increase their validity, reproducibility, and predictive value. To address these issues in the AD community, the Alzheimer's Drug Discovery Foundation partnered with Charles River Discovery Services (Morrisville, NC, USA) and Cerebricon Ltd. (Kuopio, Finland) to convene an expert advisory panel of academic, industry, and government scientists to make recommendations on best practices for animal studies testing investigational AD therapies. The panel produced recommendations regarding the measurement, analysis, and reporting of relevant AD targets, th choice of animal model, quality control measures for breeding and colony maintenance, and preclinical animal study design. Major considerations to incorporate into preclinical study design include a priori hypotheses, pharmacokinetics-pharmacodynamics studies prior to proof-of-concept testing, biomarker measurements, sample size determination, and power analysis. The panel also recommended distinguishing between pilot 'exploratory' animal studies and more extensive 'therapeutic' studies to guide interpretation. Finally, the panel proposed infrastructure and resource development, such as the establishment of a public data repository in which both positive animal studies and negative ones could be reported. By promoting best practices, these recommendations can improve the methodological quality and predictive value of AD animal studies and make the translation to human clinical trials more efficient and reliable.

2011-01-01

87

Accelerating drug discovery for Alzheimer's disease: best practices for preclinical animal studies.  

PubMed

Animal models have contributed significantly to our understanding of the underlying biological mechanisms of Alzheimer's disease (AD). As a result, over 300 interventions have been investigated and reported to mitigate pathological phenotypes or improve behavior in AD animal models or both. To date, however, very few of these findings have resulted in target validation in humans or successful translation to disease-modifying therapies. Challenges in translating preclinical studies to clinical trials include the inability of animal models to recapitulate the human disease, variations in breeding and colony maintenance, lack of standards in design, conduct and analysis of animal trials, and publication bias due to under-reporting of negative results in the scientific literature. The quality of animal model research on novel therapeutics can be improved by bringing the rigor of human clinical trials to animal studies. Research communities in several disease areas have developed recommendations for the conduct and reporting of preclinical studies in order to increase their validity, reproducibility, and predictive value. To address these issues in the AD community, the Alzheimer's Drug Discovery Foundation partnered with Charles River Discovery Services (Morrisville, NC, USA) and Cerebricon Ltd. (Kuopio, Finland) to convene an expert advisory panel of academic, industry, and government scientists to make recommendations on best practices for animal studies testing investigational AD therapies. The panel produced recommendations regarding the measurement, analysis, and reporting of relevant AD targets, th choice of animal model, quality control measures for breeding and colony maintenance, and preclinical animal study design. Major considerations to incorporate into preclinical study design include a priori hypotheses, pharmacokinetics-pharmacodynamics studies prior to proof-of-concept testing, biomarker measurements, sample size determination, and power analysis. The panel also recommended distinguishing between pilot 'exploratory' animal studies and more extensive 'therapeutic' studies to guide interpretation. Finally, the panel proposed infrastructure and resource development, such as the establishment of a public data repository in which both positive animal studies and negative ones could be reported. By promoting best practices, these recommendations can improve the methodological quality and predictive value of AD animal studies and make the translation to human clinical trials more efficient and reliable. PMID:21943025

Shineman, Diana W; Basi, Guriqbal S; Bizon, Jennifer L; Colton, Carol A; Greenberg, Barry D; Hollister, Beth A; Lincecum, John; Leblanc, Gabrielle G; Lee, Linda Bobbi H; Luo, Feng; Morgan, Dave; Morse, Iva; Refolo, Lorenzo M; Riddell, David R; Scearce-Levie, Kimberly; Sweeney, Patrick; Yrjänheikki, Juha; Fillit, Howard M

2011-09-28

88

Preclinical electrogastrography in experimental pigs  

PubMed Central

Surface electrogastrography (EGG) is a non-invasive means of recording gastric myoelectric activity or slow waves from cutaneous leads placed over the stomach. This paper provides a comprehensive review of preclinical EGG. Our group recently set up and worked out the methods for EGG in experimental pigs. We gained our initial experience in the use of EGG in assessment of porcine gastric myoelectric activity after volume challenge and after intragastric administration of itopride and erythromycin. The mean dominant frequency in pigs is comparable with that found in humans. EGG in experimental pigs is feasible. Experimental EGG is an important basis for further preclinical projects in pharmacology and toxicology.

Kvetina, Jaroslav; Varayil, Jithinraj Edakkanambeth; Ali, Shahzad Marghoob; Kunes, Martin; Bures, Jan; Tacheci, Ilja; Rejchrt, Stanislav; Kopacova, Marcela

2010-01-01

89

DTP | Toxicology and Pharmacology Branch (TPB)  

Cancer.gov

Preclinical toxicology and pharmacology are required for decision making throughout drug discovery and development and for IND filing for clinical trials. Toxicological and pharmacological data can inform clinical trial design, such as determination of maximum tolerated dose, dose-limiting toxicities, and starting dose. With appropriate characterization, in most cases, safe operating parameters can be established for human clinical trials.

90

Plant-based medicines for anxiety disorders, Part 1: a review of preclinical studies.  

PubMed

Research in the area of herbal psychopharmacology has revealed a variety of promising medicines that may provide benefit in the treatment of general anxiety and specific anxiety disorders. However, a comprehensive review of plant-based anxiolytics has been absent to date. This article (part 1) reviews herbal medicines for which only preclinical investigations for anxiolytic activity have been performed. In part 2, we review herbal medicines for which there have been clinical investigations for anxiolytic activity. An open-ended, language-restricted (English) search of MEDLINE (PubMed), CINAHL, Scopus and the Cochrane Library databases was conducted (up to 28 October 2012) using specific search criteria to identify herbal medicines that have been investigated for anxiolytic activity. This search of the literature revealed 1,525 papers, from which 53 herbal medicines were included in the full review (having at least one study using the whole plant extract). Of these plants, 21 had human clinical trial evidence (reviewed in part 2), with another 32 having solely preclinical studies (reviewed here in part 1). Preclinical evidence of anxiolytic activity (without human clinical trials) was found for Albizia julibrissin, Sonchus oleraceus, Uncaria rhynchophylla, Stachys lavandulifolia, Cecropia glazioui, Magnolia spp., Eschscholzia californica, Erythrina spp., Annona spp., Rubus brasiliensis, Apocynum venetum, Nauclea latifolia, Equisetum arvense, Tilia spp., Securidaca longepedunculata, Achillea millefolium, Leea indica, Juncus effusus, Coriandrum sativum, Eurycoma longifolia, Turnera diffusa, Euphorbia hirta, Justicia spp., Crocus sativus, Aloysia polystachya, Albies pindrow, Casimiroa edulis, Davilla rugosa, Gastrodia elata, Sphaerathus indicus, Zizyphus jujuba and Panax ginseng. Common mechanisms of action for the majority of botanicals reviewed primarily involve GABA, either via direct receptor binding or ionic channel or cell membrane modulation; GABA transaminase or glutamic acid decarboxylase inhibition; a range of monoaminergic effects; and potential cannabinoid receptor modulation. Future research should focus on conducting human clinical trials on the plants reviewed with promising anxiolytic activity. PMID:23436255

Sarris, Jerome; McIntyre, Erica; Camfield, David A

2013-03-01

91

Look back in anger - what clinical studies tell us about preclinical work.  

PubMed

Misled by animal studies and basic research? Whenever we take a closer look at the outcome of clinical trials in a field such as, most recently, stroke or septic shock, we see how limited the value of our preclinical models was. For all indications, 95% of drugs that enter clinical trials do not make it to the market, despite all promise of the (animal) models used to develop them. Drug development has started already to decrease its reliance on animal models: In Europe, for example, despite increasing R&D expenditure, animal use by pharmaceutical companies dropped by more than 25% from 2005 to 2008. In vitro studies are likewise limited: questionable cell authenticity, over-passaging, mycoplasma infections, and lack of differentiation as well as non-homeostatic and non-physiologic culture conditions endanger the relevance of these models. The standards of statistics and reporting often are poor, further impairing reliability. Alarming studies from industry show miserable reproducibility of landmark studies. This paper discusses factors contributing to the lack of reproducibility and relevance of pre-clinical research. The conclusion: Publish less but of better quality and do not rely on the face value of animal studies. PMID:23861075

Hartung, Thomas

2013-01-01

92

Food for Thought Look Back in Anger - What Clinical Studies Tell Us About Preclinical Work  

PubMed Central

Summary Misled by animal studies and basic research? Whenever we take a closer look at the outcome of clinical trials in a field such as, most recently, stroke or septic shock, we see how limited the value of our preclinical models was. For all indications, 95% of drugs that enter clinical trials do not make it to the market, despite all promise of the (animal) models used to develop them. Drug development has started already to decrease its reliance on animal models: In Europe, for example, despite increasing R&D expenditure, animal use by pharmaceutical companies dropped by more than 25% from 2005 to 2008. In vitro studies are likewise limited: questionable cell authenticity, over-passaging, mycoplasma infections, and lack of differentiation as well as non-homeostatic and non-physiologic culture conditions endanger the relevance of these models. The standards of statistics and reporting often are poor, further impairing reliability. Alarming studies from industry show miserable reproducibility of landmark studies. This paper discusses factors contributing to the lack of reproducibility and relevance of pre-clinical research. The conclusion: Publish less but of better quality and do not rely on the face value of animal studies.

Hartung, Thomas

2013-01-01

93

Issues in pharmaceutical development of thymosin alpha1 from preclinical studies through marketing.  

PubMed

SciClone Pharmaceuticals licensed the commercial and patent rights to thymosin alpha1, for geographical regions of the world excluding the United States and Europe, in the early 1990s. With this license, SciClone embarked on global drug development, and the issues encountered for thymosin alpha1 are reflective of the roller coaster of modern approval of pharmaceuticals. Most of the required toxicology studies had been completed prior to licensure, but some newer studies had to be conducted to obtain approvals in certain countries. The recent development of the "International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use" (ICH) guidelines allows for a clearer definition of the required battery of toxicology studies, although some countries still have not adopted these guidelines, and the local regulations have had to be understood and followed. Other hurdles include the complications that manufacturing requirements can differ between countries, and certain countries require local clinical experience trials in addition to SciClone's cumulative clinical data. A further obstacle was the pleiotropic nature of the mechanism of action of thymosin alpha1, with the resulting difficulty in the unraveling of its pharmacologic effects. With close attention to these regulatory details, SciClone has obtained approvals in more than 30 countries and has successfully begun commercial sales. PMID:17947591

Tuthill, Cynthia

2007-09-01

94

Preclinical and Clinical Studies of Gamma Secretase Inhibitors with Docetaxel on Human Breast Tumors  

PubMed Central

Purpose Accumulating evidence supports the existence of breast cancer stem cells (BCSCs), which are characterized by their capacity to self-renew and divide indefinitely, and resistance to conventional therapies. The Notch pathway is important for stem cell renewal, and is a potential target for BCSC-directed therapy. Experimental Design Using human breast tumorgraft studies, we evaluated the impact of gamma secretase inhibitors (GSI) on the BCSC population and the efficacy of combining GSI with docetaxel treatment. The mouse experimental therapy paralleled a concurrent clinical trial in advanced breast cancer patients, designed to determine the maximally tolerated dose of the GSI, MK-0752, administered sequentially with docetaxel, and to evaluate BCSC markers in serial tumor biopsies. Results Treatment with GSI reduced BCSCs in MC1 and BMC-2147 tumorgrafts by inhibition of the Notch pathway. GSI enhanced the efficacy of docetaxel in preclinical studies. In the clinical trial, 30 patients with advanced breast cancer were treated with escalating doses of MK-0752 plus docetaxel. Clinically meaningful doses of both drugs were possible, with manageable toxicity and preliminary evidence of efficacy. A decrease in CD44+/CD24?, ALDH+, and MSFE were observed in tumors of patients undergoing serial biopsies. Conclusions These preclinical data demonstrate that pharmacological inhibition of the Notch pathway can reduce BCSCs in breast tumorgraft models. The clinical trial demonstrates feasibility of combination GSI and chemotherapy, and together these results encourage further study of Notch pathway inhibitors in combination with chemotherapy in breast cancer.

Schott, Anne F.; Landis, Melissa D.; Dontu, Gabriela; Griffith, Kent A.; Layman, Rachel M.; Krop, Ian; Paskett, Lacey A; Wong, Helen; Dobrolecki, Lacey E.; Froehlich, Amber M.; Paranilam, Jaya; Hayes, Daniel F.; Wicha, Max S.; Chang, Jenny C.

2013-01-01

95

A COMPARATIVE STUDY OF MACHINE LEARNING ALGORITHMS APPLIED TO PREDICTIVE TOXICOLOGY DATA MINING  

Microsoft Academic Search

This paper conducted a comparative study of widely used machine algorithms applied to predictive toxicology data mining. The involved machine learning algorithms are chosen in terms of their representability and diversity, and are extensively evaluated on seven toxicity data sets which come from real- world applications. A visual analysis of the correlations of different descriptors to the class values of

96

Regulatory forum opinion piece: blind reading of histopathology slides in general toxicology studies.  

PubMed

With the intention of reducing bias, a recent European Food Safety Authority draft guidance document included a recommendation for blinded evaluation of histopathology slides in general toxicology studies (EFSA 2011). Although blinding as to treatment status reduces bias in many types of scientific experiment and is sometimes also appropriate in toxicologic pathology (Holland and Holland 2011), it is most unlikely to help achieve the overall goal of improved human safety when used for routine histopathology evaluation of tissues in general toxicology studies. This is the case because (1) blinding is not applicable to the inductive reasoning process used to identify test article effects in the tissues and would dramatically reduce the chances of these being successfully identified; and (2) in any case, the bias that would be reduced by blinding is actually a bias favoring diagnosis of a toxicological hazard and a conservative safety evaluation, which is appropriate in this context. Other unintended consequences of blinding histopathology evaluation include reductions in sensitivity for a variety of additional reasons and increased subjectivity of the pathology data. PMID:22407309

Neef, Natasha; Nikula, Kristen J; Francke-Carroll, Sabine; Boone, Laura

2012-03-09

97

Advanced Pre-Clinical Research Approaches and Models to Studying Pediatric Anesthetic Neurotoxicity  

PubMed Central

Advances in pediatric and obstetric surgery have resulted in an increase in the duration and complexity of anesthetic procedures. A great deal of concern has recently arisen regarding the safety of anesthesia in infants and children. Because of obvious limitations, it is not possible to thoroughly explore the effects of anesthetic agents on neurons in vivo in human infants or children. However, the availability of some advanced pre-clinical research approaches and models, such as imaging technology both in vitro and in vivo, stem cells, and non-human primate experimental models, have provided potentially invaluable tools for examining the developmental effects of anesthetic agents. This review discusses the potential application of some sophisticated research approaches, e.g., calcium imaging, in stem cell-derived in vitro models, especially human embryonic neural stem cells, along with their capacity for proliferation and their potential for differentiation, to dissect relevant mechanisms underlying the etiology of the neurotoxicity associated with developmental exposures to anesthetic agents. Also, this review attempts to discuss several advantages for using the developing rhesus monkey model (in vivo), when combined with dynamic molecular imaging approaches, in addressing critical issues related to the topic of pediatric sedation/anesthesia. These include the relationships between anesthetic-induced neurotoxicity, dose response, time-course, and developmental stage at time of exposure (in vivo studies), serving to provide the most expeditious platform toward decreasing the uncertainty in extrapolating pre-clinical data to the human condition.

Wang, Cheng

2012-01-01

98

Preclinical toxicological assessment of a phytotherapeutic product--CPV (based on dry extracts of Crataegus oxyacantha L., Passiflora incarnata L., and Valeriana officinalis L.).  

PubMed

Associations of plants have been widely used, for centuries, in Ayurveda and in Chinese medicine and have been increasingly acknowledged in Western medicine. The objective of this study is to assess the level of toxicity of an association of three plants: Crataegus oxyacantha, Passiflora incarnata, and Valeriana officinalis (CPV extract). This association was administered to rats, mice, and dogs, both acute and chronically for 180 days. The tests used in the acute experiments were: observational pharmacological screening, LD(50), motor coordination and motor activity. Chronic tests carried out were: weight gain/loss and behavioral parameters in rats and in mice; estrus cycle, effects on fertility, and teratogenic studies in rats and of mutagenic features in mice, in addition to the Ames test. The following parameters were assessed in dogs: weight gain/loss, general physical conditions, water/food consumption and anatomopathological examination of the organs subsequent to the 180 days of treatment. All of the results were negative, showing that CPV administered in high doses and over a long period of time presents no toxicity, suggestive of the fact that this is an association devoid of risk for human beings. PMID:19048610

Tabach, Ricardo; Rodrigues, Eliana; Carlini, E A

2009-01-01

99

Genetic toxicology: web resources.  

PubMed

Genetic toxicology is the scientific discipline dealing with the effects of chemical, physical and biological agents on the heredity of living organisms. The Internet offers a wide range of online digital resources for the field of Genetic Toxicology. The history of genetic toxicology and electronic data collections are reviewed. Web-based resources at US National Library of Medicine (NLM), including MEDLINE, PUBMED, Gateway, Entrez, and TOXNET, are discussed. Search strategies and Medical Subject Headings (MeSH) are reviewed in the context of genetic toxicology. The TOXNET group of databases are discussed with emphasis on those databases with genetic toxicology content including GENE-TOX, TOXLINE, Hazardous Substances Data Bank, Integrated Risk Information System, and Chemical Carcinogenesis Research Information System. Location of chemical information including chemical structure and linkage to health and regulatory information using CHEMIDPLUS at NLM and other databases is reviewed. Various government agencies have active genetic toxicology research programs or use genetic toxicology data to assist fulfilling the agency's mission. Online resources at the US Food and Drug Administration (FDA), the US Environmental Protection Agency (EPA), the National Institutes of Environmental Health Sciences, and the National Toxicology Program (NTP) are outlined. Much of the genetic toxicology for pharmaceuticals, industrial chemicals and pesticides that is performed in the world is regulatory-driven. Regulatory web resources are presented for the laws mandating testing, guidelines on study design, Good Laboratory Practice (GLP) regulations, and requirements for electronic data collection and reporting. The Internet provides a range of other supporting resources to the field of genetic toxicology. The web links for key professional societies and journals in genetic toxicology are listed. Distance education, educational media resources, and job placement services are also available online in the field of genetic toxicology. As molecular biology and computational tools improve, new areas within genetic toxicology such as structural activity relationship analysis, mutational spectra databases and toxicogenomics, now have resources online as well. PMID:11955688

Young, Robert R

2002-04-25

100

Preclinical studies with platelet-activating factor antagonists in models of septic shock.  

PubMed

Since the isolation and elucidation of the structure of platelet-activating factor (PAF) in the late 1970's, several preclinical studies have suggested that PAF is a key mediator of septic shock induced in animals by either endotoxin or by Gram-negative bacteria. A number of PAF antagonists have been sythesized that protect animals from the lethal effects of endotoxin. Some of these antagonists are in early stages of clinical development. The most advanced cadidate is BN 52021, a ginkgolide, that is in Phase II/III clinical trials in patients with septic shock. Preliminary results with BN 52021 indicate that it is efficacious and significantly reduces mortality associated with Gram-negative sepsis. Pivotal trials with BN 52021 aer ongoing. The present review summarizes the biological effects of PAF and the effect of PAF antagonists in animal models of septic shock. The interrelationship of PAF and tumor necrosis factor (another key mediator of septic shock) is also discussed. PMID:18611559

Dejoy, S Q; Oronsky, A L; Wick, M M; Kerwar, S S

1993-01-01

101

Granulocyte-colony stimulating factor for stroke treatment: mechanisms of action and efficacy in preclinical studies  

PubMed Central

G-CSF is widely employed for the treatment of chemotherapy-induced neutropenia. Recently, neuroprotective effects of G-CSF in animal stroke models were discovered including infarct size reduction and enhancement of functional recovery. The underlying mechanisms of action of G-CSF in ischemia appear to be a direct anti-apoptotic activity in neurons and a neurogenesis inducing capacity. Additional effects may be based on the stimulation of new blood-vessel formation, the stimulation of immunocompetence and -modulation as well as on bone marrow mobilization. In addition to a discussion of these mechanisms, we will review the available preclinical studies and analyze their impact on the overall efficacy of G-CSF in experimental stroke.

2009-01-01

102

Wireless video capsule enteroscopy in preclinical studies: methodical design of its applicability in experimental pigs.  

PubMed

The aim of this project was to develop a methodology to introduce wireless video capsule endoscopy in preclinical research. Five mature female pigs (Sus scrofa domestica) were selected for the study. Capsule endoscopes (the EndoCapsule system; Olympus) were introduced into the duodenum endoscopically in each of the animals. The life span of batteries (i.e., total time of endoscopy recording) was 487-540 min (median 492 min). The capsule endoscope reached the cecum during enteroscopy once (after 7 h 57 min), in the remaining cases, endoscopy recordings terminated in the distal or terminal ileum. All capsule enteroscopies found a normal pattern of the small intestine. The intestinal lumen is narrower, transverse folds are sparse or even absent, villi are wider but less prominent in pigs compared to humans. Capsule endoscopy in experimental pigs will be helpful for future trials on injury of different drugs and xenobiotics to the small bowel. PMID:19294508

Kopácová, Marcela; Tachecí, Ilja; Kvetina, Jaroslav; Bures, Jan; Kunes, Martin; Spelda, Stanislav; Tycová, Vera; Svoboda, Zbynek; Rejchrt, Stanislav

2009-03-18

103

Toward a checklist for exchange and interpretation of data from a toxicology study.  

PubMed

Data from toxicology and toxicogenomics studies are valuable, and can be combined for meta-analysis using public data repositories such as Chemical Effects in Biological Systems Knowledgebase, ArrayExpress, and Gene Expression Omnibus. In order to fully utilize the data for secondary analysis, it is necessary to have a description of the study and good annotation of the accompanying data. This study annotation permits sophisticated cross-study comparison and analysis, and allows data from comparable subjects to be identified and fully understood. The Minimal Information About a Microarray Experiment Standard was proposed to permit deposition and sharing of microarray data. We propose the first step toward an analogous standard for a toxicogenomics/toxicology study, by describing a checklist of information that best practices would suggest be included with the study data. When the information in this checklist is deposited together with the study data, the checklist information helps the public explore the study data in context of time, or identify data from similarly treated subjects, and also explore/identify potential sources of experimental variability. The proposed checklist summarizes useful information to include when sharing study data for publication, deposition into a database, or electronic exchange with collaborators. It is not a description of how to carry out an experiment, but a definition of how to describe an experiment. It is anticipated that once a toxicology checklist is accepted and put into use, then toxicology databases can be configured to require and output these fields, making it straightforward to annotate data for interpretation by others. PMID:17442663

Fostel, Jennifer M; Burgoon, Lyle; Zwickl, Craig; Lord, Peter; Corton, J Christopher; Bushel, Pierre R; Cunningham, Michael; Fan, Liju; Edwards, Stephen W; Hester, Susan; Stevens, James; Tong, Weida; Waters, Michael; Yang, ChiHae; Tennant, Raymond

2007-04-17

104

Assessment of candidate biomarkers of drug-induced hepatobiliary injury in preclinical toxicity studies.  

PubMed

This study was designed to assess the value of a set of potential markers for improved detection of liver injury in preclinical toxicity studies. Male Wistar rats were treated with drug candidates (BAY16, EMD335823, BI-3) that previously failed during development, in part due to hepatotoxicity, at two dose levels for 1, 3 and 14 days. Concentrations of lipocalin-2/NGAL and clusterin, which are frequently overexpressed and released from damaged tissues, and thiostatin, recently identified within PredTox as being elevated in urine in response to liver injury, were determined in rat urine and serum by ELISA. This was supplemented by confirmatory qRT-PCR and immunohistochemical analyses in the target organ. Serum paraoxonase-1 activity (PON1), which has been suggested as a marker of hepatotoxicity, was determined using a fluorometric assay. Clusterin and PON1 were not consistently altered in response to liver injury. In contrast, thiostatin and NGAL were increased in serum and urine of treated animals in a time- and dose-dependent manner. These changes correlated well with mRNA expression in the target organ and generally reflected the onset and degree of drug-induced liver injury. Receiver-operating characteristics (ROC) analyses supported serum thiostatin, but not NGAL, as a better indicator of drug-induced hepatobiliary injury than conventional clinical chemistry parameters, i.e. ALP, ALT and AST. Although thiostatin, an acute phase protein expressed in a range of tissues, may not be specific for liver injury, our results indicate that thiostatin may serve as a sensitive, minimally-invasive diagnostic marker of inflammation and tissue damage in preclinical safety assessment. PMID:20362651

Adler, M; Hoffmann, D; Ellinger-Ziegelbauer, H; Hewitt, P; Matheis, K; Mulrane, L; Gallagher, W M; Callanan, J J; Suter, L; Fountoulakis, M M; Dekant, W; Mally, A

2010-04-01

105

Integration of preclinical and clinical knowledge to predict intravenous PK in human: Bilastine case study.  

PubMed

Modern pharmacometrics can integrate and leverage all prior proprietary and public knowledge. Such methods can be used to scale across species or comparators, perform clinical trial simulation across alternative designs, confirm hypothesis and potentially reduce development burden, time and costs. Crucial yet typically lacking in integration is the pre-clinical stage. Prediction of PK in man, using in vitro and in vivo studies in different animal species, is increasingly well theorized but could still find wider application in drug development. The aim of the present work was to explore methods for bridging pharmacokinetic knowledge from animal species (i.v. and p.o.) and man (p.o.) into i.v. in man using the antihistamine drug bilastine as example. A model, predictive of i.v. PK in man, was developed on data from two pre-clinical species (rat and dog) and p.o. in man bilastine trials performed earlier. In the knowledge application stage, two different approaches were used to predict human plasma concentration after i.v. of bilastine: allometry (several scaling methods) and a semi-physiological method. Both approaches led to successful predictions of key i.v. PK parameters of bilastine in man. The predictive i.v. PK model was validated using later data from a clinical study of i.v. bilastine. Introduction of such knowledge in development permits proper leveraging of all emergent knowledge as well as quantification-based exploration of PK scenario, e.g. in special populations (pediatrics, renal insufficiency, comedication). In addition, the methods permit reduction or elimination and certainly optimization of learning trials, particularly those concerning alternative off-label administration routes. PMID:23619917

Vozmediano, Valvanera; Ortega, Ignacio; Lukas, John C; Gonzalo, Ana; Rodriguez, Monica; Lucero, Maria Luisa

2013-04-26

106

A New Three-Dimensional Ultrasound Microimaging Technology for Preclinical Studies Using a Transgenic Prostate Cancer Mouse Model  

Microsoft Academic Search

Prostate cancer is the most common cancer in adult men in North America. Preclinical studies of prostate cancer employ genetically engineered mouse models, because prostate cancer does not occur naturally in rodents. Widespread application of these models has been limited because autopsy was the only reliable method to evaluate treatment efficacy in longitudinal studies. This article reports the first use

Lauren A. Wirtzfeld; Guojun Wu; Michael Bygrave; Yasuto Yamasaki; Hideki Sakai; Madeleine Moussa; Jonathan I. Izawa; Donal B. Downey; Norman M. Greenberg; Aaron Fenster; Jim W. Xuan; James C. Lacefield

2005-01-01

107

(Environmental toxicology)  

Microsoft Academic Search

The traveler attended an International Seminar on Environmental Toxicology sponsored by Her Royal Highness Princess Chulabhorn of Thailand. The objective of the seminar was to provide technical knowledge in the area of environmental toxicology to participants from developing countries in Asia. Priorities identified at the workshop which would aid in the application of environmental toxicology principles in developing countries were:

Travis

1988-01-01

108

Midcycle Toxicology Review Memo - BAT  

Center for Biologics Evaluation and Research (CBER)

... Midcycle Toxicology Review Memo - BAT. ... Toxicology, Main Findings There were no dedicated toxicity studies performed to support this BLA. ... More results from www.fda.gov/biologicsbloodvaccines/bloodbloodproducts/approvedproducts

109

Educational Challenges in Toxicology.  

ERIC Educational Resources Information Center

Issues and topics related to educational challenges in toxicology at all levels are discussed. They include public awareness and understanding, general approach to toxicology, quality structure-activity relationships, epidemiological studies, quantification of risk, and the types of toxicants studied. (JN)

Dixon, Robert L.

1984-01-01

110

Educational Challenges in Toxicology.  

ERIC Educational Resources Information Center

|Issues and topics related to educational challenges in toxicology at all levels are discussed. They include public awareness and understanding, general approach to toxicology, quality structure-activity relationships, epidemiological studies, quantification of risk, and the types of toxicants studied. (JN)|

Dixon, Robert L.

1984-01-01

111

Vaporization--Condensation Generation of Ultrafine Hydrocarbon Particulate Matter for Inhalation Toxicology Studies  

Microsoft Academic Search

An evaporation\\/condensation particle generator produced 30-50 nm count median diameter particles from both pure hydrocarbons and from a complex mixture--used motor oil--at a concentration above 1 2 10 6 \\/cm 3 . The objective was to generate ultrafine aerosols for inhalation toxicology studies using specified organic components as surrogates for the particulate emissions generated by diesel internal combustion engines. This

John M. Veranth; Robert Gelein; Günter Oberdörster

2003-01-01

112

Developmental Toxicology--New Directions Workshop: Refining Testing Strategies and Study Designs  

PubMed Central

In April 2009, the International Life Sciences Institute (ILSI) Health and Environmental Sciences Institute’s (HESI) Developmental and Reproductive Toxicology Technical Committee held a two-day workshop entitled “Developmental Toxicology—New Directions.” The third session of the workshop focused on ways to refine animal studies to improve relevance and predictivity for human risk. The session included five presentations on: (1) considerations for refining developmental toxicology testing and data interpretation; (2) comparative embryology and considerations in study design and interpretation; (3) pharmacokinetic considerations in study design; (4) utility of genetically modified models for understanding mode-of-action; and (5) special considerations in reproductive testing for biologics. The presentations were followed by discussion by the presenters and attendees. Much of the discussion focused on aspects of refining current animal testing strategies, including use of toxicokinetic data, dose selection, tiered/triggered testing strategies, species selection, and use of alternative animal models. Another major area of discussion was use of non-animal-based testing paradigms, including how to define a “signal” or adverse effect, translating in vitro exposures to whole animal and human exposures, validation strategies, the need to bridge the existing gap between classical toxicology testing and risk assessment, and development of new technologies. Although there was general agreement among participants that the current testing strategy is effective, there was also consensus that traditional methods are resource-intensive and improved effectiveness of developmental toxicity testing to assess risks to human health is possible. This article provides a summary of the session’s presentations and discussion and describes some key areas that warrant further consideration.

Brannen, Kimberly C.; Fenton, Suzanne E.; Hansen, Deborah K.; Harrouk, Wafa; Kim, James H.; Shuey, Dana

2012-01-01

113

EFFECTS OF A BICARBONATE-ALKALINE MINERAL WATER ON GASTRIC FUNCTIONS AND FUNCTIONAL DYSPEPSIA: A PRECLINICAL AND CLINICAL STUDY  

Microsoft Academic Search

The present study was performed in order to evaluate: (1) the influence of a bicarbonate-alkaline mineral water (Uliveto®) on digestive symptoms in patients with functional dyspepsia; (2) the effects of Uliveto® on preclinical models of gastric functions. Selected patients complained of dyspeptic symptoms in the absence of digestive lesions or Helicobacter pylori infection within the previous 3 months. They were

MICHELE BERTONI; FILIPPO OLIVERI; MARTA MANGHETTI; ELENA BOCCOLINI; MARIA GRAZIA BELLOMINI; CORRADO BLANDIZZI; FERRUCCIO BONINO; MARIO DEL TACCA

2002-01-01

114

In vitro preclinical lead optimisation technologies (PLOTs) in pharmaceutical development.  

PubMed

The explosion of genuine high throughput technologies has allowed large compound libraries to be screened with ever-increasing biological specificity, exacerbating the problem of lead candidate selection for subsequent drug development. To avoid creating a bottleneck, compounds identified from the high throughput screens undergo lead optimisation by employing medium-throughput screen which permits ranking in terms of their basic absorption, distribution, metabolism, excretion (ADME) and toxicological properties. The historical role of the CRO in the drug discovery/development continuum has been to perform efficacy and toxicology studies, simply to support the regulatory submission of lead candidates. This situation is, however, changing with the development of preclinical lead optimisation technologies facilitating the selection of leading candidates, thereby bridging the gap between high throughput efficacy screens and conventional safety assessment programmes. PMID:11105205

Atterwill, C K; Wing, M G

115

An overview of prechronic and chronic toxicity/carcinogenicity experimental study designs and criteria used by the National Toxicology Program.  

PubMed Central

Since the establishment of the National Toxicology Program (NTP), there have been gradual changes in strategies to evaluate the overall toxicity of chemicals as well as their carcinogenic potential. The spectrum of toxicologic information sought on selected chemicals has been broadened by the multidisciplinary approach to evaluating chemicals. This paper describes the scientific rationale and experimental processes used by NTP in designing studies. Also, an outline of current NTP protocols are given for prechronic and chronic toxicity/carcinogenicity studies.

Chhabra, R S; Huff, J E; Schwetz, B S; Selkirk, J

1990-01-01

116

Exercise as a potential treatment for drug abuse: evidence from preclinical studies.  

PubMed

Epidemiological studies reveal that individuals who engage in regular aerobic exercise are less likely to use and abuse illicit drugs. Until recently, very few studies had examined the causal influences that mediate this relationship, and it was not clear whether exercise was effective at reducing substance use and abuse. In the past few years, several preclinical studies have revealed that exercise reduces drug self-administration in laboratory animals. These studies have revealed that exercise produces protective effects in procedures designed to model different transitional phases that occur during the development of, and recover from, a substance use disorder (e.g., acquisition, maintenance, escalation, and relapse/reinstatement of drug use). Moreover, recent studies have revealed several behavioral and neurobiological consequences of exercise that may be responsible for its protective effects in these assays. Collectively, these studies have provided convincing evidence to support the development of exercise-based interventions to reduce compulsive patterns of drug intake in clinical and at-risk populations. PMID:22347866

Smith, Mark A; Lynch, Wendy J

2012-01-12

117

Exercise as a Potential Treatment for Drug Abuse: Evidence from Preclinical Studies  

PubMed Central

Epidemiological studies reveal that individuals who engage in regular aerobic exercise are less likely to use and abuse illicit drugs. Until recently, very few studies had examined the causal influences that mediate this relationship, and it was not clear whether exercise was effective at reducing substance use and abuse. In the past few years, several preclinical studies have revealed that exercise reduces drug self-administration in laboratory animals. These studies have revealed that exercise produces protective effects in procedures designed to model different transitional phases that occur during the development of, and recover from, a substance use disorder (e.g., acquisition, maintenance, escalation, and relapse/reinstatement of drug use). Moreover, recent studies have revealed several behavioral and neurobiological consequences of exercise that may be responsible for its protective effects in these assays. Collectively, these studies have provided convincing evidence to support the development of exercise-based interventions to reduce compulsive patterns of drug intake in clinical and at-risk populations.

Smith, Mark A.; Lynch, Wendy J.

2012-01-01

118

Effects of a bicarbonate-alkaline mineral water on gastric functions and functional dyspepsia: a preclinical and clinical study.  

PubMed

The present study was performed in order to evaluate: (1) the influence of a bicarbonate-alkaline mineral water (Uliveto) on digestive symptoms in patients with functional dyspepsia; (2) the effects of Uliveto on preclinical models of gastric functions. Selected patients complained of dyspeptic symptoms in the absence of digestive lesions or Helicobacter pylori infection within the previous 3 months. They were treated with Uliveto water (1.5 l day(-1)) for 30 days. Frequency and severity of symptoms were assessed at baseline and day 30 by a score system. Preclinical experiments were carried out on rats, allowed to drink Uliveto or oligomineral water for 30 days. Animals then underwent pylorus ligation to evaluate gastric secretion of acid, pepsinogen, and mucus. In separate experiments, gastric emptying was assessed. Crenotherapy was associated with a relief of epigastric pain, retrosternal pyrosis, postprandial fullness and gastric distention. At preclinical level, Uliveto water increased acid and pepsinogen secretions as well as gastric emptying, without changes in bound mucus. The enhancing actions of Uliveto on gastric secretions and emptying were prevented by L-365,260, an antagonist of gastrin/CCK-2 receptors. These findings indicate that a regular intake of Uliveto favors an improvement of dyspeptic symptoms. The preclinical study suggests that the clinical actions of Uliveto water depend mainly on its ability to enhance gastric motor and secretory functions. PMID:12457626

Bertoni, Michele; Olivieri, Filippo; manghetti, Marta; Boccolini, Elena; Bellomini, Maria Grazia; Blandizzi, Corrado; Bonino, Ferruccio; Del Tacca, Mario

2002-12-01

119

Standardization of the Filovirus Plaque Assay for Use in Preclinical Studies  

PubMed Central

The filovirus plaque assay serves as the assay of choice to measure infectious virus in a cell culture, blood, or homogenized tissue sample. It has been in use for more than 30 years and is the generally accepted assay used to titrate virus in samples from animals treated with a potential antiviral therapeutic or vaccine. As these animal studies are required for the development of vaccines and therapeutics under the FDA Animal Rule, it is essential to have a standardized assay to compare their efficacies against the various filoviruses. Here, we present an evaluation of the conditions under which the filovirus plaque assay performs best for the Ebola virus Kikwit variant and the Angola variant of Marburg virus. The indicator cell type and source, inoculum volumes, length of incubation and general features of filovirus biology as visualized in the assay are addressed in terms of the impact on the sample viral titer calculations. These optimization studies have resulted in a plaque assay protocol which can be used for preclinical studies, and as a standardized protocol for use across institutions, to aid in data comparison. This protocol will be validated for use in GLP studies supporting advanced development of filovirus therapeutics and vaccines.

Shurtleff, Amy C.; Biggins, Julia E.; Keeney, Ashley E.; Zumbrun, Elizabeth E.; Bloomfield, Holly A.; Kuehne, Ana; Audet, Jennifer L.; Alfson, Kendra J.; Griffiths, Anthony; Olinger, Gene G.; Bavari, Sina

2012-01-01

120

Natural substances and Alzheimer's disease: from preclinical studies to evidence based medicine.  

PubMed

Over the last 10 years, the potential therapeutic effects of nutraceuticals to prevent or delay Alzheimer's disease were proposed. Among dietary antioxidants curcumin, Ginkgo biloba and carnitines were extensively studied for their neuroprotective effects. The rationale for this alternative therapeutic approach was based on several preclinical studies which suggested the neuroprotective effects for curcumin, Ginkgo biloba and acetyl-l-carnitine due to either a free radical scavenging activity or the inhibition of pro-inflammatory pathways or the potentiation of the cell stress response. However, although these are interesting premises, clinical studies were not able to demonstrate significant beneficial effects of curcumin, Ginkgo biloba and acetyl-l-carnitine in improving cognitive functions in Alzheimer's disease patients. The aim of this review is to summarize the main pharmacologic features of curcumin, Ginkgo biloba and carnitines as well as to underlie the main outcomes reached by clinical studies designed to demonstrate the efficacy of these natural substances in Alzheimer's disease patients. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease. PMID:21939756

Mancuso, Cesare; Siciliano, Raffaella; Barone, Eugenio; Preziosi, Paolo

2011-09-14

121

Preclinical Studies with Umbilical Cord Mesenchymal Stromal Cells in Different Animal Models for Muscular Dystrophy  

PubMed Central

Umbilical cord mesenchymal stromal cells (MSC) have been widely investigated for cell-based therapy studies as an alternative source to bone marrow transplantation. Umbilical cord tissue is a rich source of MSCs with potential to derivate at least muscle, cartilage, fat, and bone cells in vitro. The possibility to replace the defective muscle cells using cell therapy is a promising approach for the treatment of progressive muscular dystrophies (PMDs), independently of the specific gene mutation. Therefore, preclinical studies in different models of muscular dystrophies are of utmost importance. The main objective of the present study is to evaluate if umbilical cord MSCs have the potential to reach and differentiate into muscle cells in vivo in two animal models of PMDs. In order to address this question we injected (1) human umbilical cord tissue (hUCT) MSCs into the caudal vein of SJL mice; (2) hUCT and canine umbilical cord vein (cUCV) MSCs intra-arterially in GRMD dogs. Our results here reported support the safety of the procedure and indicate that the injected cells could engraft in the host muscle in both animal models but could not differentiate into muscle cells. These observations may provide important information aiming future therapy for muscular dystrophies.

Zucconi, Eder; Vieira, Natassia Moreira; Bueno, Carlos Roberto; Secco, Mariane; Jazedje, Tatiana; Costa Valadares, Marcos; Fussae Suzuki, Miriam; Bartolini, Paolo; Vainzof, Mariz; Zatz, Mayana

2011-01-01

122

TISSUE SLICES IN THE STUDY OF LUNG METABOLISM AND TOXICOLOGY  

EPA Science Inventory

Lung tissue slices are model systems for the study of pulmonary metabolism. Because of the speed and simplicity of slice preparation, lung slices have been used in studies of oxygen, amino acid, carbohydrate and lipid utilization and adenine nucleotide metabolism. Dose-response c...

123

Toxicology Studies with Azotomycin (Nsc 56654) IN Beagle Dogs.  

National Technical Information Service (NTIS)

The toxicity of azotomycin was studied in beagle dogs, which received single intravenous doses, 24-hour intravenous infusions, or 6 weekly intravenous doses. Azotomycin toxicosis in dogs was characterized by emesis, anorexia, mydriasis of short duration, ...

R. K. Morrison D. E. Brown E. K. Timmens M. A. Nieglos R. M. Tassini

1970-01-01

124

Preliminary toxicological study of Sylgard 184 encapsulating resin  

Microsoft Academic Search

The acute oral LDââ³° values for Sylgard 184 encapsulating resin in mice and rats were greater than 5 g\\/kg. According to classical guidelines, the compound would be considered slightly toxic or practically nontoxic in both species. Skin application studies in the rabbit demonstrated this material to be mildly irritating. Eye irritation studies, also in the rabbit, showed that Sylgard 184

D. M. Smith; G. A. Drake; J. E. London; R. G. Thomas

1978-01-01

125

Preliminary toxicological study of Sylgard 184 curing agent  

Microsoft Academic Search

The acute oral LDââ³° values for mice and rats receiving Sylgard 184 curing agent were greater than 5 g\\/kg. According to classical guidelines, the compound would be considered slightly toxic or practically nontoxic in both species. Skin application studies in the rabbit demonstrated the compound to be mildly irritating. Eye irritation studies, also in the rabbit, showed that Sylgard 184

D. M. Smith; J. E. London; G. A. Drake; R. G. Thomas

1978-01-01

126

ISOTOPIC STUDY OF THE INHALATION TOXICOLOGY OF OXIDANTS  

EPA Science Inventory

The purpose of these studies was to develop novel methods to investigate the biological fate of inhaled ozone and other oxygen-containing pollutants in animal and human tissues using the heavy isotope of oxygen, oxygen-18 (18O). Methods were developed which facilitated the conver...

127

Toxicological study of two novel pesticides on earthworm Eisenia foetida  

Microsoft Academic Search

In this paper, several studies were conducted to evaluate the toxicity of two pesticides, Imidacloprid and RH-5849 on earthworm (Eisenia foetida) in terms of their acute toxicity, biochemical toxicity and effects on sperm morphological deformity. LC50for earthworms indicated that these two pesticides had different effects in different exposure systems. The results of biochemical toxicity tests showed that lower concentrations of

Yu Luo; Yu Zang; Yuan Zhong; Zhiming Kong

1999-01-01

128

Toxicologic and Pharmacologic Studies with Lapachol (Nsf 11905).  

National Technical Information Service (NTIS)

Repeated dose studies were conducted using beagles and cynomolgus monkeys. Dogs received doses of 0.25, 0.50, 1.0 or 2.0 mg/kg/day without lethal effect. Characteristic findings at all dose levels consisted of moderate to severe anemia with reticulocytosi...

D. E. Brown E. K. Timmens J. J. Oleson R. A. Tassini R. K. Morrison

1966-01-01

129

Facilitating Multimodal Preclinical Imaging Studies in Mice by Using an Immobilization Bed  

PubMed Central

We have designed an immobilization bed that accommodates mice of all ages and sizes, to improve image registration for multimodal scans and for longitudinal preclinical imaging studies. Stationary pegs were placed such that they effectively immobilized mice and reduced set-up time. 22Na fiducial markers were placed into the pegs at unique depths to provide 3D references to facilitate image registration. Multiple users registered positron emission tomographic (PET) and CT data obtained with and without the bed to examine the effect of the bed on registration accuracy and interuser variability. The image registrations performed by different users were evaluated for their similarity by using the Entropy Correlation Coefficient as a metric. The immobilization bed significantly reduced variations in body movement and interuser variability. Average differences in quantification of tumor PET signal among users when registering images without versus with the fiduciary-marker bed fell from 9.1% to 0.8% for maximal percentage injected dose per gram (%ID/g), from 15.6% to 2.3% for mean %ID/g, and from 9.4% to 0.7% for the 90th percentile of the maximum %ID/g. The bed improves animal immobilization, greatly reduces interuser variability, and supports registration of image data acquired from different imaging sessions.

Nelson, Geoffrey S; Perez, Jessica; Colomer, Marta V; Ali, Rehan; Graves, Edward

2011-01-01

130

Preclinical animal study and clinical trail of modified extraoral craniofacial implants.  

PubMed

We report on our experience using a new endosseous implant designed to provide sufficient retention to various types of facial prostheses. In a preclinical animal experiment implants (N=12, 4 x 3.5 mm) were placed in the frontal calvarial region of nine adult pigs. The animals were sacrificed at 2, 4 and 8 weeks to evaluate the implant incorporation microradiographically. The clinical outcome and patient satisfaction of implant-retained prostheses were evaluated in a group of 10 patients with facial defects by using clinical assessment and standardized questionnaires for patients and relatives. In the prospective clinical study 33 identical modified implants for extraoral anchorage were placed for the fixation of various prostheses in the midfacial (eye, nose) and ear regions in the course of a clinical trial and observed over a follow-up period of 34 months. The bone-implant contact in the animal experiment reached 31% (+/-2) at 2 weeks, 39% (+/-1) after 4 weeks and 51% (+/-5) at 8 weeks. In the clinical trial, no implants were lost and all implants remained osseointegrated as confirmed clinically and radiographically, providing a stable prosthetic restoration. The analysis of the questionnaire indicates an improvement of the quality of life of patients with respect to aesthetic and psychological well-being. The results demonstrate that extraoral implants not only achieve sufficient osseointegration but also show good clinical handling and easy fixation possibilities for prosthetic anchorage. PMID:17392045

Petrovic, L; Schlegel, K A; Wiltfang, J; Neukam, F W; Rupprecht, S

2007-01-31

131

PRECLINICAL AND CLINICAL STUDIES ON THE INDUCTION OF RENAL ALLOGRAFT TOLERANCE THROUGH TRANSIENT MIXED CHIMERISM  

PubMed Central

Purpose of review This review updates the current status of research for induction of tolerance through a mixed chimerism approach in nonhuman primates and humans. Recent findings Allograft tolerance has been successfully achieved with a nonmyeloablative conditioning regimen and donor bone marrow transplantation in HLA-matched and mismatched kidney transplantation. In HLA-matched kidney transplantation, persistent mixed chimerism and renal allograft tolerance has been achieved in some patients. In HLA-mismatched combinations, induction of persistent mixed chimerism has not been achieved using a nonmyeloablative preparative regimen. Nevertheless, the transient mixed chimerism that has been achieved has resulted in long-term renal allograft tolerance in the majority of patients. Recent preclinical studies have demonstrated that the presence of heterologous memory T cell responses observed in primates, but not in rodents, may be a major barrier for induction of durable chimerism and tolerance in primates. Strategies to overcome such memory T cell responses may therefore be of great value in the development of reliable protocols for clinical tolerance induction. Summary Induction of tolerance in clinical kidney transplantation has been achieved via mixed chimerism approaches. Improvements in the consistency and safety of tolerance induction and extension of successful protocols to other organs and to organs from deceased donors will all be among the next steps in bringing tolerance to a wider range of clinical applications.

Kawai, Tatsuo; Cosimi, A. Benedict; Sachs, David H.

2011-01-01

132

Urine toxicology screening in Austrian trauma patients: a prospective study  

Microsoft Academic Search

Introduction  The question as to whether the patient consumed drugs prior to the trauma and which drugs were consumed, is of prime importance\\u000a for the anesthesia required during surgery. However, many patients are unwilling or unable (including those with multiple\\u000a trauma or impaired consciousness, or unconscious patients) to answer this question. The purpose of our prospective multicenter\\u000a study was to collect

Markus Figl; Linda E. Pelinka; Patrick Weninger; Christoph Walchetseder; Walter Mauritz; Harald Hertz; Albert Kroepfl; Robert Schmidhammer; Walter Buchinger; Heinz Redl

2010-01-01

133

The zoapatle IV--toxicological and clinical studies.  

PubMed

The zoapatle aqueous crude extract has been used in Mexico for the last 5 centuries for the induction of labor, treatment of post-partum bleeding problems, and as a menses inducer. Today, it is sold in street markets, and its long documented history of use by humans could be taken as indirect evidence of a lack of toxicity. Rigorous pharmacological and clinical studies described here, fully confirm the empirical observations. PMID:6851559

Southam, L; Pedrón, N; Ponce-Monter, H; Girón, H; Estrada, A; Lozoya, X; Enríquez, R G; Bejar, E; Gallegos, A J

1983-03-01

134

Preliminary toxicological study of Sylgard 184 encapsulating resin: curing agent  

Microsoft Academic Search

The acute oral LDââ³° values for Sylgard 184 (100 parts encapsulating resin plus 10 parts curing agent) were greater than 5 g\\/kg in rats and mice. According to classical guidelines, the mixture would be considered slightly toxic or practically nontoxic in both species. Skin application studies in the rabbit demonstrated the mixture to be mildly irritating. Eye irritation tests, also

D. M. Smith; G. A. Drake; J. E. London; R. G. Thomas

1978-01-01

135

Toxicological studies of two compounds isolated from Loranthus globosus Roxb.  

PubMed

The sub-acute toxicities of two compounds 3,4-dimethoxycinnamyl alcohol (1) and 3,4,5-trimethoxycinnamyl alcohol (2) isolated from the plant Loranthus globosus Roxb were studied on long Evan's rats. The studies included the gross general observation such as changes in body weight, haematological profiles [total count of Red Blood Cells (RBC) and White Blood Cells (WBC), differential count of WBC, platelet count and Haemoglobin (Hb)%], biochemical parameters of blood [Serum Glutamate Oxaloacetate Transaminase (SGOT), Serum Glutamate Pyruvate Transaminase (SGPT), Serum Alkaline Phosphatase (SALP), urea and creatinine) and histopathology of the liver, kidney, heart and lung of both control and experimental groups of rats. The changes in haematological and biochemical parameters were statistically not significant after the administration of compounds 1 and 2 in a dose of 300 microg/rat/day for consecutive 14 days. No abnormality was found in the histopathology of the liver, kidney, heart and lung in the experimental groups of rats following same dose when compared with control group. This preliminary study suggests that the isolated compounds may be used safely for clinical trial. PMID:19093449

Islam, Robiul; Alam, A H M Khurshid; Rahman, B M; Salam, K A; Hossain, Aslam; Baki, Abdullahil; Sadik, Golam

2007-06-15

136

Environmental fate and aquatic toxicology studies on phthalate esters  

SciTech Connect

A comprehensive environmental fate and effects testing program, sponsored by the Chemical Manufacturers Association (CMA) Phthalate Esters Program Panel, has been completed. Based on the results, a preliminary safety assessment has shown that all of the 14 commercially important phthalates tested have sufficiently high safety factors to demonstrate low potential for adverse environmental effects. This program comprised acute toxicity studies on nine representative species of aquatic life, chronic reproduction studies on Daphnia magna, biodegradation (fate) testing, and physicochemical property (mobility) determinations on 14 phthalate esters. The objectives of this program were to determine for each test compound: The concentration at which effects on aquatic life might occur, the potential for bioconcentration in aquatic life, and the relative persistence in the environment. These data would provide the basis for an environmental safety assessment and would identify potential effects that might require further investigation. A total of 195 individual studies were carried out. Tests on a wide variety of aquatic organisms representing different food chain levels in both fresh and salt water environments showed that no single test species was unusually sensitive to the test materials. The higher molecular weight (longer side-chain) phthalates exhibited no toxic effects up to their limits of water solubility in the test systems. Even though the lower molecular weight, more water-soluble phthalates produced toxic effects below their limits of water solubility, no product exhibited unusually severe effects of concern.

Group, E.F. Jr.

1986-03-01

137

(Environmental toxicology)  

SciTech Connect

The traveler attended an International Seminar on Environmental Toxicology sponsored by Her Royal Highness Princess Chulabhorn of Thailand. The objective of the seminar was to provide technical knowledge in the area of environmental toxicology to participants from developing countries in Asia. Priorities identified at the workshop which would aid in the application of environmental toxicology principles in developing countries were: a data base on toxicological properties of chemicals, increased research support in all aspects of science and technology in developing countries, increased public awareness and participation in the risk management process, and an increased number of training courses held in third world countries to facilitate exchange of experience and techniques.

Travis, C.C.

1988-11-28

138

Methyl isocyanate: reproductive and development toxicology studies in Swiss mice  

SciTech Connect

Studies were conducted in Swiss (CD-1) mice to evaluate the potential of inhaled vapors of methyl isocyanate (MIC) to affect reproduction and development. Inhaled MIC at concentrations of 0, 1, or 3 ppm, 6 hr per day during days 14 through 17 of gestation caused a significant increase in the number of dead fetuses at birth and caused a significant decrease in neonatal survival during lactation. In contrast, exposure of male and female mice to 1 or 3 ppm given 6 hr per day for 4 consecutive days had no effect on reproduction during mating trials conducted 1, 8, and 17 weeks after the exposure period. Similarly, there was no evidence of a dominant lethal effect in exposed male mice.

Schwetz, B.A.; Adkins, B. Jr.; Harris, M.; Moorman, M.; Sloane, R.

1987-06-01

139

Inhalation developmental toxicology studies: Gallium arsenide in mice and rats  

SciTech Connect

Gallium arsenide is a crystalline compound used extensively in the semiconductor industry. Workers preparing solar cells and gallium arsenide ingots and wafers are potentially at risk from the inhalation of gallium arsenide dust. The potential for gallium arsenide to cause developmental toxicity was assessed in Sprague- Dawley rats and CD-1 (Swiss) mice exposed to 0, 10, 37, or 75 mg/m{sup 3} gallium arsenide, 6 h/day, 7 days/week. Each of the four treatment groups consisted of 10 virgin females (for comparison), and {approx}30 positively mated rats or {approx}24 positively mated mice. Mice were exposed on 4--17 days of gestation (dg), and rats on 4--19 dg. The day of plug or sperm detection was designated as 0 dg. Body weights were obtained throughout the study period, and uterine and fetal body weights were obtained at sacrifice (rats, 20 dg; mice, 18 dg). Implants were enumerated and their status recorded. Live fetuses were sexed and examined for gross, visceral, skeletal, and soft-tissue craniofacial defects. Gallium and arsenic concentrations were determined in the maternal blood and uterine contents of the rats (3/group) at 7, 14, and 20 dg. 37 refs., 11 figs., 30 tabs.

Mast, T.J.; Greenspan, B.J.; Dill, J.A.; Stoney, K.H.; Evanoff, J.J.; Rommereim, R.L.

1990-12-01

140

A Preclinical Study of the Effects of Seabuckthorn (Hippophae rhamnoides L.) Leaf Extract on Cutaneous Wound Healing in Albino Rats  

Microsoft Academic Search

Hippophae rhamnoides L. (family Elaeagnaceae), commonly known as seabuckthorn, is a wild shrub growing at high altitude (1200-4500 meters) in adverse climatic conditions. The aim of the present study was to evaluate healing potential of seabuckthorn leaves in a preclinical study on rats using a cutaneous excision-punch wound model. Four full-thickness excision-type wounds of 8.0 mm diameter were created on

Asheesh Gupta; Ratan Kumar; Karan Pal; Pratul K. Banerjee; Ramesh C. Sawhney

2005-01-01

141

Inhalation developmental toxicology studies: Teratology study of tetrahydrofuran in mice and rats: Final report  

SciTech Connect

Tetrahydrofuran (THF), a four-carbon cyclic ether, is widely used as an industrial solvent. Although it has been used in large quantities for many years, few long-term toxicology studies, and no reproductive or developmental studies, have been conducted on THF. This study addresses the potential for THF to cause developmental toxicity in rodents by exposing Sprague-Dawley rats and Swiss (CD-1) mice to 0, 600, 1800, or 5000 ppm tetrahydrofuran (THF) vapors, 6 h/day, 7 dy/wk. Each treatment group consisted of 10 virgin females (for comparison), and approx.33 positively mated rats or mice. Positively mated mice were exposed on days 6--17 of gestation (dg), and rats on 6--19 dg. The day of plug or sperm detection was designated as O dg. Body weights were obtained throughout the study period, and uterine and fetal body weights were obtained at sacrifice (rats, 20 dg; mice, 18 dg). Implants were enumerated and their status recorded and live fetuses were examined for gross, visceral, skeletal, and soft-tissue craniofacial defects. 27 refs., 6 figs., 23 tabs.

Mast, T.J.; Evanoff, J.J.; Stoney, K.H.; Westerberg, R.B.; Rommereim, R.L.; Weigel, R.J.

1988-08-01

142

Pharmacokinetics of chemotherapeutic agents in pregnancy: a preclinical and clinical study  

Microsoft Academic Search

OBJECTIVE: To determine the impact of physiologic changes of pregnancy on pharmacokinetics of chemotherapeutic agents. DESIGN: A preclinical and a clinical case-control trial. SETTING: Institute of Primate Research Nairobi and collaborating hospitals in Belgium, the Netherlands and Czech Republic. POPULATION: Pregnant and nonpregnant women and baboons receiving chemotherapy. METHODS: Chemotherapy pharmacokinetics was compared between the pregnant and nonpregnant state. Standard-dosed

K. van Calsteren; R. Verbesselt; N. Ottevanger; M. Halaska; L. Heyns; R. de Bree; E. de Bruijn; D. Chai; M. Delforge; L. Noens; V. Renard; E. Witteveen; L. Rob; J. de Hoon; F. Amant

2010-01-01

143

Hypotensive, hypoglycaemic and toxicological studies on the flavonol C-glycoside shamimin from Bombax ceiba.  

PubMed

Shamimin, a C-flavonol glucoside from Bombax ceiba leaves showed significant potency as a hypotensive agent at the doses of 15 mg/kg, 3 mg/kg, 1 mg/kg and significant hypoglycaemic activity at 500 mg/kg in Sprague-Dawley rats. Further studies revealed that it did not cause any mortality in mice at the dose of 1 g/kg but in rats 500 mg/kg is a lethal dose. Aqueous and methanolic extracts of Bombax ceiba leaves and one of its fractions were also subjected to pharmacological and toxicological screening. PMID:10364838

Saleem, R; Ahmad, M; Hussain, S A; Qazi, A M; Ahmad, S I; Qazi, M H; Ali, M; Faizi, S; Akhtar, S; Husnain, S N

1999-05-01

144

Preclinical studies identify novel targeted pharmacological strategies for treatment of human malignant pleural mesothelioma  

PubMed Central

The incidence of human malignant pleural mesothelioma (hMPM) is still increasing worldwide. hMPM prognosis is poor even if the median survival time has been slightly improved after the introduction of the up-to-date chemotherapy. Nevertheless, large phase II/III trials support the combination of platinum derivatives and pemetrexed or raltitrexed, as preferred first-line schedule. Better understanding of the molecular machinery of hMPM will lead to the design and synthesis of novel compounds targeted against pathways identified as crucial for hMPM cell proliferation and spreading. Among them, several receptors tyrosine kinase show altered activity in subsets of hMPM. This observation suggests that these kinases might represent novel therapeutic targets in this chemotherapy-resistant disease. Over these foundations, several promising studies are ongoing at preclinical level and novel molecules are currently under evaluation as well. Yet, established tumour cell lines, used for decades to investigate the efficacy of anticancer agents, although still the main source of drug efficacy studies, after long-term cultures tend to biologically diverge from the original tumour, limiting the predictive potential of in vivo efficacy. Cancer stem cells (CSCs), a subpopulation of malignant cells capable of self-renewal and multilineage differentiation, are believed to play an essential role in cancer initiation, growth, metastasization and relapse, being responsible of chemo- and radiotherapy refractoriness. According to the current carcinogenesis theory, CSCs represent the tumour-initiating cell (TIC) fraction, the only clonogenic subpopulation able to originate a tumour mass. Consequently, the recently described isolation of TICs from hMPM, the proposed main pharmacological target for novel antitumoural drugs, may contribute to better dissect the biology and multidrug resistance pathways controlling hMPM growth.

Favoni, Roberto E; Daga, Antonio; Malatesta, Paolo; Florio, Tullio

2012-01-01

145

Tissue Damage in the Canine Normal Esophagus by Photoactivation with Talaporfin Sodium (Laserphyrin): A Preclinical Study  

PubMed Central

Background Treatment failure at the primary site after chemoradiotherapy is a major problem in achieving a complete response. Photodynamic therapy (PDT) with porfimer sodium (Photofrin®) has some problems such as the requirement for shielding from light for several weeks and a high incidence of skin phototoxicity. PDT with talaporfin sodium (Laserphyrin) is less toxic and is expected to have a better effect compared with Photofrin PDT. However, Laserphyrin PDT is not approved for use in the esophagus. In this preclinical study, we investigated tissue damage of the canine normal esophagus caused by photoactivation with Laserphyrin. Methodology/Principal Findings Diode laser irradiation was performed at 60 min after administration. An area 5 cm oral to the esophagogastric junction was irradiated at 25 J/cm2, 50 J/cm2, and 100 J/cm2 using a three-step escalation. The irradiated areas were evaluated endoscopically on postirradiation days 1 and 7, and were subjected to histological examination after autopsy. The areas injured by photoactivation were 52 mm2, 498 mm2, and 831 mm2 after irradiation at 25 J/cm2, 50 J/cm2, and 100 J/cm2, respectively. Tissue injury was observed in the muscle layer or even deeper at any irradiation level and became more severe as the irradiation dose increased. At 100 J/cm2 both inflammatory changes and necrosis were seen histologically in extra-adventitial tissue. Conclusions/Significance To minimize injury of the normal esophagus by photoactivation with Laserphyrin, diode laser irradiation at 25 J/cm2 appears to be safe. For human application, it would be desirable to investigate the optimal laser dose starting from this level.

Horimatsu, Takahiro; Muto, Manabu; Yoda, Yusuke; Yano, Tomonori; Ezoe, Yasumasa; Miyamoto, Shinichi; Chiba, Tsutomu

2012-01-01

146

Efficient production of recombinant IL-21 proteins for pre-clinical studies by a two-step dilution refolding method.  

PubMed

Produced by CD4(+) helper T cells and natural killer T (NKT) cells, interleukin-21 (IL-21) performs broad regulatory functions on B cells, CD4(+) T cells, CD8(+) T cells, NK cells and NKT cells. Targeting IL-21 to enhance the immune system has attracted great interests in the development of vaccination, anti-infection and anti-tumor therapies. Administration of IL-21 in pre-clinical models is however limited by relatively high expense of the recombinant IL-21 protein. Here, we report a rapid and cost-effective method to produce IL-21 using Escherichia coli (E. coli) by introducing a novel two-step dilution strategy for refolding. The method has been validated to produce milligrams of human IL-21, human IL-21/IL-4 chimera and mouse IL-21 with high bioactivities and low endotoxin, mostly suitable for in vitro and in vivo pre-clinical studies. PMID:23474188

Chen, Zhian; Cui, Yanfang; Leong, Yew Ann; Beddoe, Travis; Yu, Di

2013-03-06

147

Preclinical safety evaluation of moxifloxacin, a novel fluoroquinolone.  

PubMed

The toxicity of moxifloxacin (BAY 12-8039), a novel fluoroquinolone with a broad spectrum of antibacterial activity, was evaluated in a comprehensive programme of toxicological studies that included single and multiple dose toxicity studies in rats, mice, dogs and monkeys, reproductive system toxicity studies in rats and monkeys and in-vitro and in-vivo mutagenicity assays. Although moxifloxacin is not intended for long-term clinical use, an accelerated bioassay in target organs to assess carcinogenesis was performed in rats. In addition to the routine toxicological programme required for the development of a drug intended for short-term administration, a major part of the preclinical programme for moxifloxacin comprised studies designed specifically to address the safety issues known to be features of fluoroquinolones, i.e. adverse effects on the central nervous and cardiovascular systems, phototoxicity, arthrotoxicity and oculotoxicity. The results of the toxicological investigations confirmed that the safety profile of moxifloxacin is comparable to those of other fluoroquinolones. PMID:10382881

von Keutz, E; Schlüter, G

1999-05-01

148

Toxicological profile of therapeutic nanodelivery systems.  

PubMed

Several of the newly developed drug molecules show potent biological activity, but exhibit poor pharmacokinetic properties that may hinder their effective delivery to the intended site of action. In order to improve their pharmacological effect, these molecules can be associated with drug carriers in order to overcome these inherent difficulties. An ideal drug delivery agent requires therefore biocompatibility, improved solubility of a loaded drug or peptide, releasing of the payload at the absorption site and, at the same time, leaving undisturbed cell structure and function, and maintaining the physiological milieu. By taking advantage of the valuable properties of nanoscale delivery systems, such as increased surface area, improved solubility of hydrophobic drugs, possibility to encapsulate and protect drugs from degradation and reduced immunogenic potential and toxicological effect, new therapeutic options can be brought forth and improve the clinical arsenal for numerous diseases. The use of nanodelivery systems can even promote the re-investigation of pharmacokinetically less favourable, but biologically more active compounds. Although very promising, these systems may also encompass inherent toxicological issues, mainly due to their size and shape, physical interaction with cellular membranes and organelles, immunological reactions, long- or short-term tissue accumulation, and degradation products. Pharmaceutical nanodelivery systems, such as liposomes, polymeric nanoparticles, dendrimers and mesoporous silica and silicon based nanoparticles have shown great potential in preclinical applications and several of these nanosystems are even undergoing clinical trials. They have been found to combine drug delivery properties with an acceptable toxicological profile, which has made them prime candidates for several drug delivery approaches. This review aims to provide and correlate the toxicological studies with the drug delivery properties of the above mentioned nanodelivery systems in particular concerning uptake and accumulation as well as the critical aspects in each system regarding their optimal performance, while pointing out to the most relevant references. PMID:22380014

Bimbo, Luis M; Peltonen, Leena; Hirvonen, Jouni; Santos, Helder A

2012-10-01

149

Radiopaque contrast media. XLIV - Preclinical studies with a new nonionic contrast agent.  

PubMed

L-5-alpha-hydroxypropionylamino-2,4,6-triiodoisophthalic acid di-(1,3-dihydroxy-2-propylamide), abbreviated Iopamidol, a new non-ionic water soluble contrast agent for angiography, myelography, ventriculography and for contrast reinforced computer-assisted axial tomography is described. Extensive preclinical testing showed favorable physico-chemical features of the new compound, low systemic toxicity, excellent cardiovascular and renal tolerability, very mild effects on the blood-brain barrier and on nervous tissue. PMID:923795

Felder, E; Pitrè, D; Tirone, P

1977-11-01

150

Uses of available record systems in epidemiologic studies of reproductive toxicology.  

PubMed

The uses of available record systems in epidemiologic studies of reproductive toxicology are described with reference to New York State. The available record systems (and relevant reproductive end points) described include: a newborn screening program for metabolic diseases and hemoglobinopathies (relevant to point mutations); chromosome registries and prenatal cytogenetics (for chromosome anomalies); live birth certificates (for birth defects, birthweight, sex ratio, etc); fetal death certificates (for spontaneous fetal deaths); and a statewide cancer registry (for childhood cancers and transplacental carcinogenesis). The uses and limitations of these record systems are discussed, along with examples of their use in descriptive and analytic epidemiologic studies. Descriptive studies outlined include investigations of temporal and geographic trends in birth defects, birth weight, and fetal deaths, with reference to environmental questions (eg, Love Canal, nuclear power plants). Analytic studies described concern parental occupation in relation to specific birth defects (neural tube defects and Down syndrome) and maternal use of contraceptive drugs. PMID:6220602

Polednak, A P; Janerich, D T

1983-01-01

151

Uses of available record systems in epidemiologic studies of reproductive toxicology  

SciTech Connect

The uses of available record systems in epidemiologic studies of reproductive toxicology are described with reference to New York State. The available record systems (and relevant reproductive end points) described include: a newborn screening program for metabolic diseases and hemoglobinopathies (relevant to point mutations); chromosome registries and prenatal cytogenetics (for chromosome anomalies); live birth certificates (for birth defects, birthweight, sex ratio, etc); fetal death certificates (for spontaneous fetal deaths); and a statewide cancer registry (for childhood cancers and transplacental carcinogenesis). The uses and limitations of these record systems are discussed, along with examples of their use in descriptive and analytic epidemiologic studies. Descriptive studies outlined include investigations of temporal and geographic trends in birth defects, birth weight, and fetal deaths, with reference to environmental questions (eg, Love Canal, nuclear power plants). Analytic studies described concern parental occupation in relation to specific birth defects (neural tube defects and Down syndrome) and maternal use of contraceptive drugs.

Polednak, A.P.; Janerich, D.T.

1983-01-01

152

Equivalence of concentration-response relationships in aquatic toxicology studies: Testing and implications for potency estimation  

SciTech Connect

The purpose of this study was to describe statistical procedures to test the equivalence of concentration-response relationships in acute toxicology studies and to illustrate the implications of nonequivalence on potency endpoints such as LC10, LC50, or LC90. A logistic regression model for binary response endpoints such as mortality that allowed for the examination of equivalence of slopes and intercepts of the responses between populations is described. Test statistics were derived from comparing nested regression models. This procedure was used to test the equivalence of concentration versus acute mortality response relationships between two nonpolar, narcotic chemicals in a single population of fish and between two populations of fish with different exposure histories to a polycyclic aromatic hydrocarbon. These case studies illustrate different outcomes in the comparison of concentration-response relationships and demonstrate the need to consider more than a single endpoint (e.g., LC50) in a risk assessment context when nonparallel concentration-responses are observed.

Oris, J.T. [Miami Univ., Oxford, OH (United States). Center for Environmental Toxicology and Statistics

1997-10-01

153

NTP Technical Report on the Toxicology and Carcinogenesis Study of Ethinyl Estradiol (CAS NO. 57-63-6) in Sprague-Dawley Rats (Feed Study).  

National Technical Information Service (NTIS)

Ethinyl estradiol is a potent synthetic estrogen widely usedin pharmaceutical preparations. Its high potency and wide-spread use led to its selection by the National ToxicologyProgram for inclusion in studies to examine endocrine disrupting compounds with...

2010-01-01

154

Phenesterin (Nsc - 104 469): Preclinical Toxicity of 14 Oral Treatments (Q 4 Day) in Rhesus Monkeys.  

National Technical Information Service (NTIS)

Phenesterin, (Cholest - 5 en, 3 beta - hydroxy -, (p -(bis (2 - Chloroethyl) amino) phenyl) - acetate) (NSC - 104 469) a compound with potent antitumor activity was submitted to a preclinical toxicological evaluation in 8 Rhesus monkeys. Groups of 2 monke...

I. Heyman U. Schaeppi G. Thompson D. A. Cooney R. D. Davis

1970-01-01

155

Ovarian toxicity and carcinogenicity in eight recent National Toxicology Program studies.  

PubMed Central

Ovarian toxicity and/or carcinogenicity has been documented for at least eight chemicals recently tested in National Toxicity Program prechronic and chronic rodent studies. The chemicals that yielded treatment-related ovarian lesions were 1,3-butadiene, 4-vinylcyclohexene, vinylcyclohexene deipoxide, nitrofurantoin, nitrofurazone, benzene, delta-9-tetrahydrocannabinol, and tricresylphosphate. Typical nonneoplastic ovarian changes included hypoplasia, atrophy, follicular necrosis, and tubular hyperplasia. The most commonly observed treatment-related neoplasms were granulosa cell tumors and benign mixed tumors. A relationship between antecedent ovarian hypoplasia, atrophy, and hyperplasia and subsequent ovarian neoplasia is supported by some of these National Toxicology Program studies. Pathologic changes in other tissues such as the adrenal glands and uterus were associated with the treatment-related ovarian changes.

Maronpot, R R

1987-01-01

156

Ovarian toxicity and carcinogenicity in eight recent national toxicology program studies  

SciTech Connect

Ovarian toxicity and/or carcinogenicity has been documented for at least eight chemicals recently tested in National Toxicity Program prechronic and chronic rodent studies. The chemicals that yielded treatment-related ovarian lesions were 1,3-butadiene, 4-vinylcyclohexene, vinylcylohexene deipoxide, nitrofurantoin, nitrofurazone, benzene, ..delta..-9-tetrahydrocannabinol, and tricresylphosphate. Typical nonneoplastic ovarian changes included hypoplasia, atrophy, follicular necrosis, and tubular hyperplasia. The most commonly observed treatment-related neoplasms were granulosa cell tumors and benign mixed tumors. A relationship between antecedent ovarian hypoplasia, atrophy, and hyperplasia and subsequent ovarian neoplasia is supported by some of these National Toxicology Program studies. Pathologic changes in other tissues such as the adrenal glands and uterus were associated with the treatment-related ovarian changes.

Maronpot, R.R.

1987-08-01

157

Physicochemical and toxicological studies on 4-chloro-3,5-dinitrobenzoic acid in aqueous solutions.  

PubMed

Physicochemical characterization of hazardous compounds often is required for the development of structure-reactivity correlations. Physical, chemical, and toxicological properties of target pollutants require determination for an efficient application of wastewater treatments. In the present work, we chose a chloro-nitro-aromatic derivative (4-chloro-3,5-dinitrobenzoic acid [CDNBA]), as a model compound on which to perform physicochemical and toxicological studies. Several properties of CDNBA are not available in the literature, although many aromatic nitro-compounds are considered hazardous materials. Measurements of solubility in water, acid dissociation constant, and kinetic parameters for the nucleophilic substitution of chlorine atom in alkaline media are reported. We also performed cytotoxicity studies of CDNBA and ultraviolet-irradiated CDNBA solutions. From the analysis of CDNBA solubility in water at different temperatures, an enthalpy of solution of 23.2 +/- 2.5 kJ/mol was found. The study of the acid dissociation constant Kc by using conductivity measurements and the modified Gran's method yielded values for the equilibrium constant Ka of 2.36 x 10(-3) and 2.26 x 10(-3), respectively. The bimolecular rate constant for the reaction of CDNB- and hydroxyl ion (HO) measured at room temperature and 0.1 M of ionic strength was 5.92/M x s, and the activation energy for this process was 70.7 +/- 3.4 kJ/mol. Cytotoxicity assays with aqueous suspensions of Tetrahymena pyriformis showed lethal effects due to the pH change induced by CDNBA. On the other hand, in buffered solutions, a value of 104.47 microM was observed for the median effective concentration, that is, the concentration of CDNBA at which the proliferation was restricted to one half of the blank. Irradiation of CDNBA solutions increased the toxicity, suggesting the formation of intermediate products with higher cytotoxicity effects. PMID:15180363

Lopez, Jorge L; García Einschlag, Fernando S; Rives, Carina V; Villata, Laura S; Capparelli, Alberto L

2004-05-01

158

Zebrafish (Danio rerio) neuromast: promising biological endpoint linking developmental and toxicological studies.  

PubMed

Aquatic toxicology is facing the challenge to assess the impact of complex mixtures of compounds on diverse biological endpoints. So far, ecotoxicology focuses mainly on apical endpoints such as growth, lethality and reproduction, but does not consider sublethal toxic effects that may indirectly cause ecological effects. One such sublethal effect is toxicant-induced impairment of neurosensory functions which will affect important behavioural traits of exposed organisms. Here, we critically review the mechanosensory lateral line (LL) system of zebrafish as a model to screen for chemical effects on neurosensory function of fish in particular and vertebrates in general. The LL system consists of so-called neuromasts, composed of centrally located sensory hair cells, and surrounding supporting cells. The function of neuromasts is the detection of water movements that is essential for the fish's ability to detect prey, to escape predator, to socially interact or to show rheotactic behaviour. Recent advances in the study of these organs provided researchers with a broad area of molecular tools for easy and rapid detection of neuromasts dysfunction and/or disturbed development. Further, genes involved in neuromasts differentiation have been identified using auditory/mechanosensory mutants and morphants. A number of environmental toxicants including metals and pharmaceuticals have been shown to affect neuromasts development and/or function. The use of the LL organ for toxicological studies offers the advantage to integrate the available profound knowledge on developmental biology of the neuromasts with the study of chemical toxicity. This combination may provide a powerful tool in environmental risk assessment. PMID:19467721

Froehlicher, Mirjam; Liedtke, Anja; Groh, Ksenia J; Neuhauss, Stephan C F; Segner, Helmut; Eggen, Rik I L

2009-04-24

159

Integration of mutation and chromosomal damage endpoints into 28-day repeat dose toxicology studies.  

PubMed

Two endpoints of genetic toxicity, mutation at the X-linked Pig-a gene and chromosomal damage in the form of micronucleated reticulocytes (MN-RETs), were evaluated in blood samples obtained from 28-day repeat-dosing studies typical of those employed in toxicity evaluations. Male Wistar Han rats were treated at 24-h intervals on days 1 through 28 with one of five prototypical genotoxicants: N-ethyl-N-nitrosourea, 7,12-dimethyl-12-benz[a]anthracene, 4-nitroquinoline-1-oxide (4NQO), benzo(a)pyrene, and N-methyl-N-nitrosourea. Flow cytometric scoring of CD59-negative erythrocytes (indicative of glycosylphosphatidylinositol anchor deficiency and hence Pig-a mutation) was performed using blood specimens obtained on days -1, 15, 29, and 56. Blood specimens collected on days 4 and 29 were evaluated for MN-RET frequency using flow cytometry-based MicroFlow Kits. With the exception of 4NQO, each chemical induced significant increases in the frequency of MN-RETs on days 4 and 29. All five agents increased the frequency of mutant phenotype (CD59 negative) reticulocytes (RETs) and erythrocytes. Mutation responses in RETs occurred earlier than in erythrocytes and tended to peak, or nearly peak, at day 29. In contrast, the mutant phenotype erythrocyte responses were modest on day 29 and required additional time to reach their maximal value. The observed kinetics were expected based on the known turnover of RETs and erythrocytes. The data show that RETs can serve as an appropriate indicator cell population for 28-day studies. Collectively, these data suggest that blood-based genotoxicity endpoints can be effectively incorporated into routine toxicology studies, a strategy that would reduce animal usage while providing valuable genetic toxicity information within the context of other toxicological endpoints. PMID:20202993

Dertinger, Stephen D; Phonethepswath, Souk; Franklin, Dean; Weller, Pamela; Torous, Dorothea K; Bryce, Steven M; Avlasevich, Svetlana; Bemis, Jeffrey C; Hyrien, Ollivier; Palis, James; MacGregor, James T

2010-03-04

160

Integration of Mutation and Chromosomal Damage Endpoints into 28-Day Repeat Dose Toxicology Studies  

PubMed Central

Two endpoints of genetic toxicity, mutation at the X-linked Pig-a gene and chromosomal damage in the form of micronucleated reticulocytes (MN-RETs), were evaluated in blood samples obtained from 28-day repeat-dosing studies typical of those employed in toxicity evaluations. Male Wistar Han rats were treated at 24-h intervals on days 1 through 28 with one of five prototypical genotoxicants: N-ethyl-N-nitrosourea, 7,12-dimethyl-12-benz[a]anthracene, 4-nitroquinoline-1-oxide (4NQO), benzo(a)pyrene, and N-methyl-N-nitrosourea. Flow cytometric scoring of CD59-negative erythrocytes (indicative of glycosylphosphatidylinositol anchor deficiency and hence Pig-a mutation) was performed using blood specimens obtained on days ?1, 15, 29, and 56. Blood specimens collected on days 4 and 29 were evaluated for MN-RET frequency using flow cytometry–based MicroFlow Kits. With the exception of 4NQO, each chemical induced significant increases in the frequency of MN-RETs on days 4 and 29. All five agents increased the frequency of mutant phenotype (CD59 negative) reticulocytes (RETs) and erythrocytes. Mutation responses in RETs occurred earlier than in erythrocytes and tended to peak, or nearly peak, at day 29. In contrast, the mutant phenotype erythrocyte responses were modest on day 29 and required additional time to reach their maximal value. The observed kinetics were expected based on the known turnover of RETs and erythrocytes. The data show that RETs can serve as an appropriate indicator cell population for 28-day studies. Collectively, these data suggest that blood-based genotoxicity endpoints can be effectively incorporated into routine toxicology studies, a strategy that would reduce animal usage while providing valuable genetic toxicity information within the context of other toxicological endpoints.

Dertinger, Stephen D.; Phonethepswath, Souk; Franklin, Dean; Weller, Pamela; Torous, Dorothea K.; Bryce, Steven M.; Avlasevich, Svetlana; Bemis, Jeffrey C.; Hyrien, Ollivier; Palis, James; MacGregor, James T.

2010-01-01

161

Inclusion of Biomarkers for Detecting Perturbations in the Heart and Lung and Lipid\\/Carbohydrate Metabolism in National Toxicology Program Studies  

Microsoft Academic Search

Environmental factors and exposures may contribute to many serious diseases afflicting humans. Biomarkers are useful to understand disease processes and identify early events leading to disease. The National Toxicology Program (NTP) convened a workshop in September 2006 to help identify biomarkers that could be used in toxicology studies with rodents to predict disease outcome and detect early events in disease

June K. Dunnick; Kristina A. Thayer; Gregory S. Travlos

2007-01-01

162

Toxicological studies on silver nanoparticles: challenges and opportunities in assessment, monitoring and imaging.  

PubMed

Silver nanoparticles (Ag NPs) are becoming increasingly prevalent in consumer products as antibacterial agents. The increased use of Ag NP-enhanced products may lead to an increase in toxic levels of environmental silver, but regulatory control over the use or disposal of such products is lagging due to insufficient assessment on the toxicology of Ag NPs and their rate of release into the environment. In this article we discuss recent research on the transport, activity and fate of Ag NPs at the cellular and organismic level, in conjunction with traditional and recently established methods of nanoparticle characterization. We include several proposed mechanisms of cytotoxicity based on such studies, as well as new opportunities for investigating the uptake and fate of Ag NPs in living systems. PMID:21793678

Stensberg, Matthew Charles; Wei, Qingshan; McLamore, Eric Scott; Porterfield, David Marshall; Wei, Alexander; Sepúlveda, María Soledad

2011-07-01

163

Toxicological studies on silver nanoparticles: challenges and opportunities in assessment, monitoring and imaging  

PubMed Central

Silver nanoparticles (Ag NPs) are becoming increasingly prevalent in consumer products as antibacterial agents. The increased use of Ag NP-enhanced products may lead to an increase in toxic levels of environmental silver, but regulatory control over the use or disposal of such products is lagging due to insufficient assessment on the toxicology of Ag NPs and their rate of release into the environment. In this article we discuss recent research on the transport, activity and fate of Ag NPs at the cellular and organismic level, in conjunction with traditional and recently established methods of nanoparticle characterization. We include several proposed mechanisms of cytotoxicity based on such studies, as well as new opportunities for investigating the uptake and fate of Ag NPs in living systems.

Stensberg, Matthew Charles; Wei, Qingshan; McLamore, Eric Scott; Porterfield, David Marshall; Wei, Alexander; Sepulveda, Marla Soledad

2012-01-01

164

UNUSUAL FINDINGS IN ZEBRAFISH, DANIO RERIO, FROM TOXICOLOGICAL STUDIES AND THE ZEBRAFISH INTERNATIONAL RESOURCE CENTER DIAGNOSTIC SERVICE  

EPA Science Inventory

A number of interesting and unusual lesions have been diagnosed in zebrafish that have been evaluated from toxicological studies or submitted as cases to the Diagnostic Service at Oregon State University. Lesions were observed in various wild-type and mutant lines of zebrafish an...

165

OPTIMIZATION OF THE HAMILTON-THORN COMPUTERIZED SPERM MOTILITY ANALYSIS SYSTEM FOR USE WITH RAT SPERMATOZOA IN TOXICOLOGICAL STUDIES  

EPA Science Inventory

To optimize the Hamilton-Thorn Motility Analyzer (HIM, Hamilton-Thorn Research, Beverly, MA) for use in reproductive toxicology studies with rat spermatozoa, the accuracy and precision of the instrument were assessed under a variety of instrument settings. ideotapes of both fast ...

166

The role of the toxicologic pathologist in the biopharmaceutical industry.  

PubMed

Toxicologic pathologists contribute significantly to the development of new biopharmaceuticals, yet there is often a lack of awareness of this specialized role. As the members of multidisciplinary teams, toxicologic pathologists participate in all aspects of the drug development process. This review is part of an initiative by the Society of Toxicologic Pathology to educate scientists about toxicologic pathology and to attract junior scientists, veterinary students, and veterinarians into the field. We describe the role of toxicologic pathologists in identifying candidate agents, elucidating bioactive pathways, and evaluating efficacy and toxicity in preclinical animal models. Educational and specialized training requirements and the challenges of working in a global environment are discussed. The biopharmaceutical industry provides diverse, challenging, and rewarding career opportunities in toxicologic pathology. We hope that this review promotes understanding of the important role the toxicologic pathologist plays in drug development and encourages exploration of an important career option. PMID:21878555

van Tongeren, Susan; Fagerland, Jane A; Conner, Michael W; Diegel, Kelly; Donnelly, Kevin; Grubor, Branka; Lopez-Martinez, Alric; Bolliger, Anne Provencher; Sharma, Alok; Tannehill-Gregg, Sarah; Turner, Patricia V; Wancket, Lyn M

2011-08-30

167

Pre-Clinical Studies of Epigenetic Therapies Targeting Histone Modifiers in Lung Cancer  

PubMed Central

Treatment options for lung cancer patients have been generally limited to standard therapies or targeted interventions which involve a small number of known mutations. Although the targeted therapies are initially successful, they most often result in drug resistance, relapse, and mortality. We now know that the complexity of lung cancer comes not only from genomic changes, but also from aberrant epigenetic regulatory events. Epigenetic therapies have shown promise as single agents in the treatment of hematological malignancies but have yet to meet this expectation in solid tumors thus fostering researchers to pursue new approaches in the development and use of epigenetic interventions. Here, we review some recent pre-clinical findings involving the use of drugs targeting histone modifying enzymes both as single agents and as co-therapies against lung cancer. A greater understanding of the impact of these epigenetic compounds in lung cancer signaling is needed and further evaluation in vivo is warranted in several cases based on the pre-clinical activity of a subset of compounds discussed in this review, including drugs co-targeting HDACs and EGF receptor, targeting Brd4 and targeting Jumonji histone demethylases.

Huffman, Kenneth; Martinez, Elisabeth D.

2013-01-01

168

Preclinical Acute Toxicity Studies and Dosimetry Estimates of the Novel Sigma1 Receptor Radiotracer, [ 18 F]SFE  

Microsoft Academic Search

[18F]1-(2-Fluoroethyl)-4-[(4-cyanophenoxy)methyl]piperidine ([18F]SFE) is a novel, selective, high-affinity sigma-1 receptor radioligand that has been preclinically well characterized in rodents. To support an investigational new drug (IND) application for the first evaluation of [18F]SFE in humans, single-organ and whole-body radiation adsorbed doses associated with [18F]SFE injection were estimated from rat distribution data. In addition, single- and multiple-dose toxicity studies were conducted in

Rikki N. Waterhouse; Jun Zhao; Michael G. Stabin; Hanna Ng; Janice Schindler-Horvat; Raymond C. Chang; Jon C. Mirsalis

2006-01-01

169

Creation of a digital slide and tissue microarray resource from a multi-institutional predictive toxicology study in the rat: an initial report from the PredTox group.  

PubMed

The widespread use of digital slides has only recently come to the fore with the development of high-throughput scanners and high performance viewing software. This development, along with the optimisation of compression standards and image transfer techniques, has allowed the technology to be used in wide reaching applications including integration of images into hospital information systems and histopathological training, as well as the development of automated image analysis algorithms for prediction of histological aberrations and quantification of immunohistochemical stains. Here, the use of this technology in the creation of a comprehensive library of images of preclinical toxicological relevance is demonstrated. The images, acquired using the Aperio ScanScope CS and XT slide acquisition systems, form part of the ongoing EU FP6 Integrated Project, Innovative Medicines for Europe (InnoMed). In more detail, PredTox (abbreviation for Predictive Toxicology) is a subproject of InnoMed and comprises a consortium of 15 industrial (13 large pharma, 1 technology provider and 1 SME) and three academic partners. The primary aim of this consortium is to assess the value of combining data generated from 'omics technologies (proteomics, transcriptomics, metabolomics) with the results from more conventional toxicology methods, to facilitate further informed decision making in preclinical safety evaluation. A library of 1709 scanned images was created of full-face sections of liver and kidney tissue specimens from male Wistar rats treated with 16 proprietary and reference compounds of known toxicity; additional biological materials from these treated animals were separately used to create 'omics data, that will ultimately be used to populate an integrated toxicological database. In respect to assessment of the digital slides, a web-enabled digital slide management system, Digital SlideServer (DSS), was employed to enable integration of the digital slide content into the 'omics database and to facilitate remote viewing by pathologists connected with the project. DSS also facilitated manual annotation of digital slides by the pathologists, specifically in relation to marking particular lesions of interest. Tissue microarrays (TMAs) were constructed from the specimens for the purpose of creating a repository of tissue from animals used in the study with a view to later-stage biomarker assessment. As the PredTox consortium itself aims to identify new biomarkers of toxicity, these TMAs will be a valuable means of validation. In summary, a large repository of histological images was created enabling the subsequent pathological analysis of samples through remote viewing and, along with the utilisation of TMA technology, will allow the validation of biomarkers identified by the PredTox consortium. The population of the PredTox database with these digitised images represents the creation of the first toxicological database integrating 'omics and preclinical data with histological images. PMID:18479893

Mulrane, Laoighse; Rexhepaj, Elton; Smart, Valerie; Callanan, John J; Orhan, Diclehan; Eldem, Türkan; Mally, Angela; Schroeder, Susanne; Meyer, Kirstin; Wendt, Maria; O'Shea, Donal; Gallagher, William M

2008-05-13

170

The Humanized NOD/SCID Mouse as a Preclinical Model to Study the Fate of Encapsulated Human Islets  

PubMed Central

Despite encouraging results in animal models, the transplantation of microencapsulated islets into humans has not yet reached the therapeutic level. Recent clinical trials using microencapsulated human islets in barium alginate showed the presence of dense fibrotic overgrowth around the microcapsules with no viable islets. The major reason for this is limited understanding of what occurs when encapsulated human islets are allografted. This warrants the need for a suitable small animal model. In this study, we investigated the usefulness of NOD/SCID mice reconstituted with human PBMCs (called humanized NOD/SCID mice) as a preclinical model. In this model, human T cell engraftment could be achieved, and CD45+ cells were observed in the spleen and peripheral blood. Though the engrafted T cells caused a small fibrotic overgrowth around the microencapsulated human islets, this failed to stop the encapsulated islets from functioning in the diabetic recipient mice. The ability of encapsulated islets to survive in this mouse model might partly be attributed to the presence of Th2 cytokines IL-4 and IL-10, which are known to induce graft tolerance. In conclusion, this study showed that the hu-NOD/SCID mouse is not a suitable preclinical model to study the allograft rejection mechanisms of encapsulated human islets. As another result, the maintained viability of transplanted islets on the NOD/SCID background emphasized a critical role of protective mechanisms in autoimmune diabetes transplanted subjects due to specific immunoregulatory effects provided by IL-4 and IL-10.

Vaithilingam, Vijayaganapathy; Oberholzer, Jose; Guillemin, Gilles J.; Tuch, Bernard E.

2010-01-01

171

Cardiac arterial spin labeling using segmented ECG-gated Look-Locker FAIR: variability and repeatability in preclinical studies.  

PubMed

MRI is important for the assessment of cardiac structure and function in preclinical studies of cardiac disease. Arterial spin labeling techniques can be used to measure perfusion noninvasively. In this study, an electrocardiogram-gated Look-Locker sequence with segmented k-space acquisition has been implemented to acquire single slice arterial spin labeling data sets in 15 min in the mouse heart. A data logger was introduced to improve data quality by: (1) allowing automated rejection of respiration-corrupted images, (2) providing additional prospective gating to improve consistency of acquisition timing, and (3) allowing the recombination of uncorrupted k-space lines from consecutive data sets to reduce respiration corruption. Finally, variability and repeatability of perfusion estimation within-session, between-session, between-animal, and between image rejection criteria were assessed in mice. The criterion used to reject images from the T(1) fit was shown to affect the perfusion estimation. These data showed that the between-animal coefficient of variability (24%) was greater than the between-session variability (17%) and within-session variability (11%). Furthermore, the magnitude of change in perfusion required to detect differences was 30% (within-session) and 55% (between-session) according to Bland-Altman repeatability analysis. These technique developments and repeatability statistics will provide a platform for future preclinical studies applying cardiac arterial spin labeling. PMID:22411842

Campbell-Washburn, Adrienne E; Price, Anthony N; Wells, Jack A; Thomas, David L; Ordidge, Roger J; Lythgoe, Mark F

2012-03-12

172

Novel direct factor IIa and Xa inhibitors: mechanisms of action and preclinical studies.  

PubMed

The need to overcome certain limitations of the existing anticoagulant agents (heparin, LMWH and VKAs) and to achieve more convenient long-term anticoagulation has fueled the quest for the "ideal anticoagulant", an agent that would exert at least similar antithrombotic effects with a substantially improved pharmacologic profile and significantly less bleeding complications. The major disadvantages of the traditional agents were the narrow therapeutic window with serious drug and food interactions and the need for regular blood monitoring. Coagulation factors IIa and Xa have proved the most attractive pharmacologic targets due to their key role in the coagulation process and the opportunity of blocking thrombin generation before the level of thrombin production that results in amplification of the anticoagulant effect while preserving some of thrombin hemostatic effect. This review summarizes the mechanism of action of some of the most promising novel oral direct factor IIa and Xa inhibitors with a focus on published preclinical trials that led to their clinical development. PMID:22564123

Deftereos, Spyridon; Anatoliotakis, Nikolaos; Giannopoulos, Georgios; Kaoukis, Andreas; Mavri, Maria; Pyrgakis, Vlasios; Stefanadis, Christodoulos

2012-08-01

173

Focused ultrasound-induced blood-brain barrier opening to enhance temozolomide delivery for glioblastoma treatment: a preclinical study.  

PubMed

The purpose of this study is to assess the preclinical therapeutic efficacy of magnetic resonance imaging (MRI)-monitored focused ultrasound (FUS)-induced blood-brain barrier (BBB) disruption to enhance Temozolomide (TMZ) delivery for improving Glioblastoma Multiforme (GBM) treatment. MRI-monitored FUS with microbubbles was used to transcranially disrupt the BBB in brains of Fisher rats implanted with 9L glioma cells. FUS-BBB opening was spectrophotometrically determined by leakage of dyes into the brain, and TMZ was quantitated in cerebrospinal fluid (CSF) and plasma by LC-MS\\MS. The effects of treatment on tumor progression (by MRI), animal survival and brain tissue histology were investigated. Results demonstrated that FUS-BBB opening increased the local accumulation of dyes in brain parenchyma by 3.8-/2.1-fold in normal/tumor tissues. Compared to TMZ alone, combined FUS treatment increased the TMZ CSF/plasma ratio from 22.7% to 38.6%, reduced the 7-day tumor progression ratio from 24.03 to 5.06, and extended the median survival from 20 to 23 days. In conclusion, this study provided preclinical evidence that FUS BBB-opening increased the local concentration of TMZ to improve the control of tumor progression and animal survival, suggesting its clinical potential for improving current brain tumor treatment. PMID:23527068

Wei, Kuo-Chen; Chu, Po-Chun; Wang, Hay-Yan Jack; Huang, Chiung-Yin; Chen, Pin-Yuan; Tsai, Hong-Chieh; Lu, Yu-Jen; Lee, Pei-Yun; Tseng, I-Chou; Feng, Li-Ying; Hsu, Peng-Wei; Yen, Tzu-Chen; Liu, Hao-Li

2013-03-19

174

[From medicolegal toxicology to forensic toxicology].  

PubMed

The importance of forensic toxicology has been increasing until now, because of the increasing numbers of toxic substances and poisoning incidents. In Japan, a special translational word "houi-chudoku-gaku" has been used for the forensic toxicology especially in the field of legal medicine. The Japanese word, however, does not seem appropriate for translation of forensic toxicology, because it covers medicine, pharmacy and police sciences interdisciplinary. In 1980, Emeritus Prof. Hidetoshi Yoshimura created an appropriate word "hochudoku-gaku" for translation of forensic toxicology. In 1982, Prof. Yoshimura and his friends established the Japanese Association of Forensic Toxicology, consisting of people from legal medicine, pharmacy and police institutes. This Association enabled lively discussions among different fields and greatly contributed to advances of forensic toxicology in Japan. We started studies of forensic toxicology using gas chromatography (GC)/mass spectrometry (MS) in 1979. Until now, we delt with solid-phase extraction (1987-1994), surface ionization GC (1989-1997), negative ion chemical ionization MS (1981-now), solid-phase microextraction (1994-now), cryogenic oven trapping GC (1997-now), surface ionization organic MS (1998-now) and high-performance liquid chromatography/tandem MS (1998-now). In this review, the author presents some details of solid-phase microextraction, negative ion chemical ionization MS, cryogenic oven trapping GC and surface ionization organic MS. Unprecedented poisoning terrorism by use of sarin took place in Matsumoto and Tokyo in 1994 and 1995, respectively. On July 25, 1998, a curry poisoning incident using arsenious acid occurred in Wakayama, resulting in the death of 4 people and injury of 63 people. Since then, more than 30 imitative poisoning cases have been reported by mass communication within 1 year. In spite of the above continuing poisoning cases, almost no effective measures have been taken by the administration of our country and local governments. Many serious problems concerning poisoning and drug abuse are accumulating in Japan. In this review, the problems are also made manifest, and some proposals are presented to solve the problems. PMID:11218750

Suzuki, O

2000-11-01

175

Latent Structure and Factorial Invariance of a Neuropsychological Test Battery for the Study of Preclinical Alzheimer's Disease  

PubMed Central

Objective To examine the latent structure of a test battery currently being used in a longitudinal study of asymptomatic middle-aged adults with a parental history of Alzheimer’s disease (AD) and test the invariance of the factor solution across subgroups defined by selected demographic variables and known genetic risk factors for AD. Method An exploratory factor analysis (EFA) and a sequence of confirmatory factor analyses (CFA) were conducted on 24 neuropsychological measures selected to provide a comprehensive estimate of cognitive abilities most likely to be affected in preclinical AD. Once the underlying latent model was defined and the structural validity established through model comparisons, a multi-group confirmatory factor analysis model was used to test for factorial invariance across groups. Results The EFA solution revealed a factor structure consisting of 5 constructs: verbal ability, visuo-spatial ability, speed & executive function, working memory, and verbal learning & memory. The CFA models provided support for the hypothesized 5-factor structure. Results indicated factorial invariance of the model across all groups examined. Conclusions Collectively, the results suggested a relatively strong psychometric basis for using the factor structure in clinical samples that match the characteristics of this cohort. This confirmed an invariant factor structure should prove useful in research aimed to detect the earliest cognitive signature of preclinical AD in similar middle aged cohorts.

Dowling, N. Maritza; Hermann, Bruce; La Rue, Asenath; Sager, Mark A.

2010-01-01

176

Advances in reproductive toxicology  

SciTech Connect

Research in reproductive toxicology has relied on several animal models as well as on the more difficult-to-perform human studies. In animals, ovarian toxicity is being investigated in more detail, with investigation of characteristics of reversibility. Epidemiology studies using time-to-pregnancy techniques have been useful in identifying potential at-risk populations for further study. Male toxicology research has concentrated on defining normal sperm parameters in experimental animals and in men, particularly when those parameters are evaluated by computer-assisted techniques.37 references.

Scialli, A.R. (Department of Obstetrics and Gynecology, Georgetown University Medical Center, Washington, DC (United States))

1992-06-01

177

The effect of genistein aglycone on cancer and cancer risk: a review of in vitro, preclinical, and clinical studies.  

PubMed

In Asian epidemiological studies, health benefits, including reduced incidence of breast and prostate cancers, are attributed to soy food and isoflavone consumption. The recent increased intake of soy foods and supplements in the American diet has raised concerns about the possible estrogen-like effects of natural isoflavones and possible promotion or propagation of estrogen-sensitive cancers. These concerns are primarily based on in vitro and rodent data which suggest that genistein aglycone can stimulate tumor cell proliferation and growth in mice having deficient immune systems. In contrast, a recent nested case-control study and meta-analysis of numerous epidemiological studies show an inverse correlation between genistein intake and breast cancer risk. Furthermore, clinical studies in osteopenic and osteoporotic, postmenopausal women support the breast and uterine safety of purified naturally derived genistein administered for up to 3 years. In this review, we summarize the in vitro, preclinical and clinical evidence for the safety of natural genistein. PMID:19566600

Taylor, Christopher K; Levy, Robert M; Elliott, Jay C; Burnett, Bruce P

2009-07-01

178

Production, composition and toxicology studies of Enzogenol® Pinus radiata bark extract.  

PubMed

Enzogenol® pine bark extract is a dietary supplement and food ingredient produced by water extraction of Pinus radiata. We present production method, composition, and safety data from rat and dog toxicological and human clinical studies. The dry powder contains proanthocyanidins (>80%), taxifolin (1-2%), other flavonoids and phenolic acids (up to 8%), and carbohydrates (5-10%). Reverse mutation assays showed lack of mutagenic activity. Single and 14-day repeat dosing in rats and dogs had no influence on body weight, feed consumption, blood chemistry, and haematology at any dose level. There were no treatment related findings on gross and detailed necroscopy, organ weights, organ weight ratios and histology. The only adverse events were emesis and diarrhoea in dogs occurring mainly in un-fed condition and at the highest dose level in a total of 18% of applications. The MTD and NOAEL in the present rat and dog studies were 2500 and 750 mg/kg/day, respectively. Consumption of 480 mg/day for 6 months and 960 mg/day for 5 weeks in two human studies showed Enzogenol® had no adverse influence on liver and kidney function, haematology, and did not cause any adverse events. Our studies indicate lack of toxicity of Enzogenol® and support safe use as a food ingredient. PMID:22982471

Frevel, Mathias A E; Pipingas, Andrew; Grigsby, Warren J; Frampton, Chris M; Gilchrist, Nigel L

2012-09-12

179

Endoscopic minimally invasive thyroidectomy (eMIT): some clarifications regarding the idea, development, preclinical studies, and application in humans.  

PubMed

BACKGROUND: The transoral endoscopic approach for thyroid surgery was based on a previous attempt to reach the thyroid gland by an axilloscope. In contrast to this single-port access, endoscopic minimally invasive thyroidectomy (eMIT) uses three access points (sublingual and bivestibular). This results in a sufficient triangulation of instruments, making surgical procedures in the anterior neck region possible. METHODS: The idea and development of the eMIT technique are described in detail. Anatomic studies, the development of the surgical access in a cadaver study, and the animal study for safety and feasibility of this transoral endoscopic approach for surgery of the anterior neck are outlined. Also, the foundations and ethical aspects are addressed in the context of developing a surgical innovation, which resulted in the first clinical application of this technique in humans. RESULTS: The preclinical studies regarding endoscopic minimally invasive thyroidectomy proofed feasibility in a human cadaver studies as well as safety in a short-time survival animal study. The first clinical application in a 53-year old patient was successful without any significant complications; expected benefits (no postoperative pain or dysphagia, no visible scar) could be demonstrated. CONCLUSIONS: The eMIT technique represents a promising new surgical approach for endoscopic surgery in the anterior neck region. The whole development was based on principles for surgical innovation published after the authors' preclinical studies. At this writing, after an initial clinical study with humans, the time has come to compare this new technique with other endoscopic and minimally invasive approaches in a prospective randomized multicenter trial. PMID:20734066

Wilhelm, Thomas; Metzig, Andreas

2010-08-24

180

Toxicological study of pesticides in air and precipitations of Paris by means of a bioluminescence method.  

PubMed

A detailed toxicological study on several pesticides, including chlorothalonil, cyprodynil, dichlobénil, pendimethaline, trifluraline, and alpha-endosulfan, present at trace levels in air and total atmospheric precipitations of Paris is presented. The pesticides contained in the atmospheric samples, collected during sampling campaigns in February-March 2007, are identified and quantified by a high-performance liquid chromatographic (HPLC)-UV detection method. The toxicity measurements are performed by means of the Microtox bioluminescence method, based on the evaluation of the bioluminescence inhibition of the Vibrio fischeri marine bacteria at two exposure times to the pesticide solutions. The specific toxicity, corresponding to the particular toxicity of the compound under study and represented by the EC(50) parameter, is determined for these pesticides. Also, the global toxicity, which is the toxicity of all micro-pollutants present in the sample under study, is estimated for the extracts of air and atmospheric precipitation (rainwater) samples. The specific toxicities strongly vary with the nature of the pesticide, the EC(50) parameter values being comprised between 0.17 and 0.83 mg/mL and 0.15 and 0.66 mg/mL, respectively, for exposure times of 5 and 15 min. The importance of the atmospheric samples' global toxicity and the respective contribution of the toxic potency of the various pesticides contained in these samples are discussed. PMID:19387620

Trajkovska, S; Mbaye, M; Gaye Seye, M D; Aaron, J J; Chevreuil, M; Blanchoud, H

2009-04-22

181

Targeted Toxins for Glioblastoma Multiforme: pre-clinical studies and clinical implementation  

PubMed Central

Glioblastoma multiforme (GBM) is most common primary brain tumor in adults. GBM is very aggressive due to its poor cellular differentiation and invasiveness, which makes complete surgical resection virtually impossible. Therefore, GBM’s invasive nature as well as its intrinsic resistance to current treatment modalities makes it a unique therapeutic challenge. Extensive examination of human GBM specimens has uncovered that these tumors overexpress a variety of receptors that are virtually absent in the surrounding non-neoplastic brain. Human GBMs overexpress receptors for cytokines, growth factors, ephrins, urokinase-type plasminogen activator (uPA), and transferrin, which can be targeted with high specificity by linking their ligands with highly cytotoxic molecules, such as Diptheria toxin and Pseudomonas exotoxin A. We review the preclinical development and clinical translation of targeted toxins for GBM. In view of the clinical experience, we conclude that although these are very promising therapeutic modalities for GBM patients, efforts should be focused on improving the delivery systems utilized in order to achieve better distribution of the immuno-toxins in the tumor/resection cavity. Delivery of targeted toxins using viral vectors would also benefit enormously from improved strategies for local delivery.

Candolfi, Marianela; Kroeger, Kurt M.; Xiong, Weidong; Liu, Chunyan; Puntel, Mariana; Yagiz, Kader; Ghulam Muhammad, AKM; Mineharu, Yohei; Foulad, David; Wibowo, Mia; Assi, Hikmat; Baker, Gregory J.; Lowenstein, Pedro R.; Castro, Maria G.

2011-01-01

182

Platinum formulations as anticancer drugs clinical and pre-clinical studies.  

PubMed

This review summarizes clinical and pre-clinical results on platinum anti-cancer drug formulations. A concise summary of the use of oxidation state to modulate cancer pharmacology is given for Pt(IV) complexes, distinct from the clinically used Pt(II) drugs. The chemistry of platinum drug formulation combines aspects of kinetics of active moiety release from nominally weak-binding ligands (bond cleavage from platinum-carboxylate and platinum-phosphate) in polymers and nanoparticles with pharmacological considerations of plasma distribution and cellular accumulation. The action of any molecular entity as a drug is influenced by its ADME profile--absorption, distribution, metabolism and excretion. The purpose of drug formulation is to alter any or all of these parameters with the ultimate goal of improving the efficacy and reducing side effects with the possibility to target drugs directly to the tumor site. The diverse array of approaches includes liposomes, polymers (not limited to peptides, dendrimers, biodegradable polymers, polysaccharides, and metallic nanoparticles). Functionalization of the surfaces of nanoparticles with antibodies or cellular surface recognition motifs may further target specific cancers. PMID:22039867

P Farrell, Nicholas

2011-01-01

183

[Classification of results of studying blood plasma with laser correlation spectroscopy based on semiotics of preclinical and clinical states].  

PubMed

The usage of laser correlation spectroscopy for verification of preclinical and clinical states is substantiated. Developed "semiotic" classifier for solving the problems of preclinical and clinical states is presented. The substantiation of biological algorithms as well as the mathematical support and software for the proposed classifier for the data of laser correlation spectroscopy of blood plasma are presented. PMID:9848161

Ternovo?, K S; Kryzhanovski?, G N; Musi?chuk, Iu I; Noskin, L A; Klopov, N V; Noskin, V A; Starodub, N F

184

The underlying toxicological mechanism of chemical mixtures: A case study on mixture toxicity of cyanogenic toxicants and aldehydes to Photobacterium phosphoreum.  

PubMed

Intracellular chemical reaction of chemical mixtures is one of the main reasons that cause synergistic or antagonistic effects. However, it still remains unclear what the influencing factors on the intracellular chemical reaction are, and how they influence on the toxicological mechanism of chemical mixtures. To reveal this underlying toxicological mechanism of chemical mixtures, a case study on mixture toxicity of cyanogenic toxicants and aldehydes to Photobacterium phosphoreum was employed, and both their joint effects and mixture toxicity were observed. Then series of two-step linear regressions were performed to describe the relationships between joint effects, the expected additive toxicities and descriptors of individual chemicals (including concentrations, binding affinity to receptors, octanol/water partition coefficients). Based on the quantitative relationships, the underlying joint toxicological mechanisms were revealed. The result shows that, for mixtures with their joint effects resulting from intracellular chemical reaction, their underlying toxicological mechanism depends on not only their interaction with target proteins, but also their transmembrane actions and their concentrations. In addition, two generic points of toxicological mechanism were proposed including the influencing factors on intracellular chemical reaction and the difference of the toxicological mechanism between single reactive chemicals and their mixtures. This study provided an insight into the understanding of the underlying toxicological mechanism for chemical mixtures with intracellular chemical reaction. PMID:23811331

Tian, Dayong; Lin, Zhifen; Zhou, Xianghong; Yin, Daqiang

2013-06-26

185

Regulatory toxicology considerations for the development of inhaled pharmaceuticals.  

PubMed

The preclinical safety studies required to support the development of inhaled drugs are generally the same as for other routes of administration. Repeat-dose toxicology studies should be conducted by inhalation to ensure the characterization of both the local (i.e., respiratory) and systemic toxicity, although some studies (e.g., reproductive) can be performed by utilizing alternative routes, when it is paramount to maximize systemic exposure. Respiratory tract changes in preclinical species can include irritancy of the larynx and nasal cavity, particularly in rodents. Such changes are not necessarily predictive of a risk to humans because of the exquisite sensitivity of the rodent larynx and the lack of exposure to the nasal cavity after oro-inhalation of drugs in the clinical setting. The design of poorly soluble molecules to limit systemic exposure places greater emphasis on the elimination of drugs from the lungs by macrophages. Consequently, an increase in macrophage numbers is often noted, and in the absence of any other changes, this is generally considered to be a nonadverse, physiological response to an inhaled particulate. Other changes in the lung, which can include an inflammatory response and/or epithelial hyperplasia, resulting from irritancy or particulate overload, are a safety concern and are not monitorable in humans. For such changes, safety margins can be calculated in terms of the drug deposited per unit weight of lung. These factors should be taken into account when designing preclinical studies or programs for inhaled drugs. PMID:22273711

Owen, Keith

2012-01-25

186

Unscheduled deoxyribonucleic acid (DNA) synthesis assays for toxicological studies. May 1977-March 1990 (A Bibliography from the NTIS data base). Report for May 1977-March 1990  

SciTech Connect

This bibliography contains citations concerning the unscheduled DNA synthesis (UDS) assay for toxicological studies. UDS assays provide very sensitive measures of damage to DNA by detecting induction of DNA synthesis in non-S-phase cells. UDS toxicological studies analyzing gamma radiation, drugs, pesticides, nerve gas, jet engine fuels, ultraviolet light, chlorated organic compounds, and aromatic compounds are discussed. UDS studies using both human and animal tissue cultures are described. (Contains 57 citations fully indexed and including a title list.)

Not Available

1990-04-01

187

scyllo-Inositol, preclinical, and clinical data for Alzheimer's disease.  

PubMed

Preclinical development of scyllo-inositol for the treatment of Alzheimer's disease (AD) has been investigated in both in vitro and in vivo models with positive results. scyllo-Inositol stabilized a small conformer of A?42 in vitro, neutralized cell derived A? trimers and promoted low molecular weight A? species in vivo. These interactions resulted in decreased neuronal toxicity, increased long-term potentiation (LTP) and ablation of cognitive deficits in multiple mouse models of AD. scyllo-Inositol bioavailability, pharmacokinetics, and small animal toxicology studies demonstrated the potential for translation to human patients. The results of Phase I and Phase II clinical trials for AD are presented. Furthermore, the use of this compound for imaging and other amyloid related disorders is discussed. PMID:22840748

Ma, Keran; Thomason, Lynsie A M; McLaurin, JoAnne

2012-01-01

188

Analytical toxicology  

Microsoft Academic Search

\\u000a This paper reviews procedures for screening, identification and quantification of drugs, poisons and their metabolites in\\u000a biosamples, and the corresponding work-up procedures. Gas chromatography-mass spectrometry and liquid chromatography-mass\\u000a spectrometry are mostly used today in analytical toxicology. Selection of the most appropriate biosample, e.g., ante\\/postmortem\\u000a blood, urine, or tissues or alternative matrices like hair, sweat and oral fluid, nails or meconium,

Hans H. Maurer

189

Forensic toxicology  

Microsoft Academic Search

\\u000a Forensic toxicology has developed as a forensic science in recent years and is now widely used to assist in death investigations,\\u000a in civil and criminal matters involving drug use, in drugs of abuse testing in correctional settings and custodial medicine,\\u000a in road and work-place safety, in matters involving environmental pollution, as well as in sports doping. Drugs most commonly\\u000a targeted

Olaf H. Drummer

190

Aspartame: a safety evaluation based on current use levels, regulations, and toxicological and epidemiological studies.  

PubMed

Aspartame is a methyl ester of a dipeptide used as a synthetic nonnutritive sweetener in over 90 countries worldwide in over 6000 products. The purpose of this investigation was to review the scientific literature on the absorption and metabolism, the current consumption levels worldwide, the toxicology, and recent epidemiological studies on aspartame. Current use levels of aspartame, even by high users in special subgroups, remains well below the U.S. Food and Drug Administration and European Food Safety Authority established acceptable daily intake levels of 50 and 40 mg/kg bw/day, respectively. Consumption of large doses of aspartame in a single bolus dose will have an effect on some biochemical parameters, including plasma amino acid levels and brain neurotransmitter levels. The rise in plasma levels of phenylalanine and aspartic acid following administration of aspartame at doses less than or equal to 50 mg/kg bw do not exceed those observed postprandially. Acute, subacute and chronic toxicity studies with aspartame, and its decomposition products, conducted in mice, rats, hamsters and dogs have consistently found no adverse effect of aspartame with doses up to at least 4000 mg/kg bw/day. Critical review of all carcinogenicity studies conducted on aspartame found no credible evidence that aspartame is carcinogenic. The data from the extensive investigations into the possibility of neurotoxic effects of aspartame, in general, do not support the hypothesis that aspartame in the human diet will affect nervous system function, learning or behavior. Epidemiological studies on aspartame include several case-control studies and one well-conducted prospective epidemiological study with a large cohort, in which the consumption of aspartame was measured. The studies provide no evidence to support an association between aspartame and cancer in any tissue. The weight of existing evidence is that aspartame is safe at current levels of consumption as a nonnutritive sweetener. PMID:17828671

Magnuson, B A; Burdock, G A; Doull, J; Kroes, R M; Marsh, G M; Pariza, M W; Spencer, P S; Waddell, W J; Walker, R; Williams, G M

2007-01-01

191

A review of inhalation toxicology studies with para-aramid fibrils.  

PubMed

The paper summarizes the results of inhalation toxicology studies associated with para-aramid (p-aramid) fibrils. The review is subdivided into two categories: the results of inhalation toxicity studies and mechanistic inhalation studies. Keratin-associated lesions were observed in the lungs of female rats following chronic exposure to high concentrations of p-aramid. These lesions were originally interpreted as cystic keratinizing squamous cell carcinomas (CKSCC). In recent years, this keratinizing lesion has been observed in the lungs of rats with greater regularity in numerous chronic inhalation studies following exposures to a variety of dusts. In an attempt to reach a consensus on an appropriate diagnosis for this lesion, an international panel of pathologists was convened to evaluate the morphological aspects of this lesion. The panel considered that the most appropriate diagnosis for this lesion was 'proliferative keratin cyst' (PKC), the biological potential of the PKC remains controversial, but it appears to be unique to the rat species and has little relevance for humans. Mechanistic studies with p-aramid have demonstrated that acute inhalation of high concentrations of fibrils produces a potent but transient pulmonary inflammatory and cell labelling response. The inhaled fibrils have low durability in the lungs of rats as evidenced by a progressive decrease in median fibre lengths with increasing residence time in the lung. In contrast, in a comparative study, size-separated chrysotile asbestos produced a sustained increase over controls in cellular proliferation responses of terminal airways, parenchyma, subpleural and mesothelial regions.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8526399

Warheit, D B

1995-10-01

192

Toxicology 1: Toxicology and Living Systems  

NSDL National Science Digital Library

In the first lesson, Toxicology 1: Toxicology and Living Systems, students are introduced to the basic concepts and terminology of the science. Toxicology 2: Finding the Toxic Dose allows students the opportunity to conduct a toxicology experiment on a plant. Specifically, students determine the toxic dose of a chemical that will inhibit seed germination in Brassica rapa, a relative to cabbages and mustards. In the third lesson, Toxicology 3: Toxicology and Human Health, students investigate the effect of environmental tobacco smoke on human lung development. These lessons can be done in a series or they can stand alone.

American Association for the Advancement of Science (;)

2005-06-13

193

Potential application of immobilized and perfused hepatocytes in environmental toxicology studies.  

PubMed

Conventional cellular models have contributed significantly to the understanding of many aspects of cell physiology and molecular biology. In these models cells are metabolically less active, due to the inefficient oxygenation and waste product buildup. Therefore perfusion methods for the cells are expected to improve cell activities. Cells have to be fixed in or on an appropriate inert carrier or support, which enables cellular perfusion, maintains integrated cellular functions and makes a bioreactor. Since isolated hepatocytes are extensively used in biomedical studies including those dealing with environmental pollutants or toxins and in xenobiotic biotransformation investigations, an efficient hepatocyte perfusion model has to be available for researchers. This research article is focusing on the value of hepatocyte immobilization as a laboratory bioreactor model and is shedding light on its potentiality in research related to public health. We demonstrate the application of this cellular model as a means to study representative phase I and phase II biotransformation reactions using hexobarbital hydroxylation and 7-ethoxycoumarin deethylation and 4-chloro 2-dinitrobenzene glutathione. Both phase I and phase II drug biotransformation in hepatocytes was demonstrated in this study non-destructively to the cells and in an efficient way. In spite of the aforementioned advantages, immobilized hepatocytes yet have relatively limited applications compared to conventional hepatocyte cellular systems. Reasons for this discrepancy are discussed. This cellular system may become popular due to the better performance of immobilized hepatocytes as compared to conventional hepatocyte culture and due to economic and ethical reasons. Naturally its applicability will cover several biomedical areas including basic research in environmental toxicology and other public health issues. PMID:11503272

Farghali, H; Lincová, D; Kmonícková, E; Bencko, V

2001-05-01

194

Recent studies in the behavioral toxicology of ELF electric and magnetic fields  

Microsoft Academic Search

Behavioral responses to ELF electric and magnetic fields are reviewed starting with the simple sensory awareness or detection by an animal and moving on through more-complicated behavioral responses such as behavior that averts exposure. The literature selected in this review is taken primarily from the area of behavioral toxicology. As such, it does not review work on specialized response systems

Lovely

1988-01-01

195

Zebrafish ( Danio rerio) neuromast: Promising biological endpoint linking developmental and toxicological studies  

Microsoft Academic Search

Aquatic toxicology is facing the challenge to assess the impact of complex mixtures of compounds on diverse biological endpoints. So far, ecotoxicology focuses mainly on apical endpoints such as growth, lethality and reproduction, but does not consider sublethal toxic effects that may indirectly cause ecological effects. One such sublethal effect is toxicant-induced impairment of neurosensory functions which will affect important

Mirjam Froehlicher; Anja Liedtke; Ksenia J. Groh; Stephan C. F. Neuhauss; Helmut Segner; Rik I. L. Eggen

2009-01-01

196

INTEGRATED TECHNOLOGY-BASED TOXICOLOGY STUDIES ON DRINKING WATER DISINFECTION BYPRODUCTS (DBPS)  

EPA Science Inventory

DBPs are formed by reactions of chemical disinfectants with natural organic matter in the source water. Although more than 300 DBPs are known, many remain unidentified; for chlorination, known DBPs account for ~50% of the mass of total organic halide. Toxicological evaluation o...

197

Indoor and outdoor airborne particles. An in vitro study on mutagenic potential and toxicological implications  

Microsoft Academic Search

Introduction<\\/strong>Air pollution components are present as gases and as particulate matter. As particle deposition takes place in various parts of the respiratory system particulate matter may have other toxicological implications than gaseous pollutants, which all may penetrate in the lower part of the respiratory tract. In addition, suspended particulate matter represents a group of pollutants of variable physical as well

Houdt van J. J

1988-01-01

198

New designer drug p-methoxymethamphetamine: studies on its metabolism and toxicological detection in urine using gas chromatography–mass spectrometry  

Microsoft Academic Search

Studies are described on the metabolism and the toxicological analysis of the new designer drug rac-p-methoxymethamphetamine (PMMA) in rat urine using gas chromatography–mass spectrometry (GC–MS). The identified metabolites indicated that PMMA was extensively metabolized mainly by O-demethylation to pholedrine and to a minor extent to p-methoxyamphetamine (PMA), 1-hydroxypholedrine diastereomers (one being oxilofrine), 4?-hydroxy-3?-methoxymethamphetamine and 4?-hydroxy-3?-methoxyamphetamine. The authors’ systematic toxicological analysis

Roland F. Staack; Josef Fehn; Hans H. Maurer

2003-01-01

199

Chemical and toxicological studies of coal gasification wastewater circulated through a cooling tower  

SciTech Connect

Argonne National Laboratory is studying health and environmental issues related to coal gasification, using data and samples from the oxygen-blown slagging fixed-bed gasifier at the University of North Dakota Energy Research Center (UNDERC). The pilot study reported here developed preliminary chemical and toxicological data needed to evaluate the health and environmental, as well as the process, implications of using partially treated gasifier wastewater in cooling towers. This minimal-treatment process removes organic compounds by solvent extraction and removes ammonia and acid gas by steam stripping; then, without intermediate biological treatment, the wastewater is reused in a cooling tower. Samples were collected of both the influent wastewater to the cooling tower and the effluent in the tower's blowdown pipeline. These samples were analyzed for the presence of organic chemicals and trace metals and tested for mutagenic and teratologic activity. Results indicate that the UNDERC solvent-extracted and steam-stripped coal gasification wastewaters doe not contain any easily observed mutagenic or cytotoxic activity. The blowdown water sampled was not cytotoxic or mutagenic after phenol removal and ten-fold concentration. Initial indications are that UNDEREC cooling tower blowdown water may contain teratogenically active compounds. Phenolic material is volatilized in the cooling tower and 85 to 90% is lost as a vapor effluent. Probably less than 10% oxidative degradation of phenols occurs in the UNDERC cooling tower. Hydantoins and most inorganic elements are concentrated in the blowdown water approximately ten-fold, as expected. Trace element distributions of zinc and lead in the blowdown water are not as predicted and are unexplained. The aerodynamic size of the drift aerosol may be 12 ..mu..m or greater, depending on the characteristics of the cooling tower's eliminators. 26 references, 2 figures, 13 tables.

Stetter, J.R.; Stamoudis, V.C.; Flotard, R.D.; Reilly, C.A., Jr.; Wilzbach, K.E.

1984-08-01

200

Genetic Toxicology Evaluation: Bacterial Mutagenesis  

Center for Food Safety and Applied Nutrition (CFSAN)

Text Version... In the event that the study contains additional types of information included as part of the ... GENETIC TOXICOLOGY STUDIES: ... More results from www.fda.gov/downloads/food/guidanceregulation

201

Toxicology Education Foundation  

MedlinePLUS

... increase the public understanding of toxicology. ! Support for the Toxicology Education Foundation comes from individuals, government, institutions and companies. ---Select---- Programs & Activities Travel Awards ...

202

Toxicology and Carcinogenesis Studies of Oxytetracycline Hydrochloride (CAS No. 2058-46-0) in F344/N Rats and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies were conducted on oxytetracycline hydrochloride by administering the test chemical in feed to F344/N rats and B6C3F1 mice. These studies were conducted by administering diets containing 0, 25,000, or 50,000 p...

1987-01-01

203

Preclinical students: who are surgeons?  

Microsoft Academic Search

Introduction: We have previously demonstrated that even a brief intervention by surgeons can positively influence perceptions of preclinical medical students. The purpose of the present study was to determine the origin of negative perceptions regarding surgery and if perceptions differ between students with or without an interest in surgery (+surg or -surg). Methods: A qualitative study was performed by conducting

R. A. Kozar; K. D. Anderson; S. L. Escobar-Chaves; M. A. Thiel; S. I. Brundage

2003-01-01

204

Preclinical pharmacology of docetaxel.  

PubMed

Docetaxel is a taxoid cytotoxic agent which promotes tubulin assembly into microtubles and inhibits their depolymerisation. In vitro, docetaxel reduces murine and human tumour cell survival by 50% at concentrations of 4-35 ng/ml, with a greater cytotoxic effect on proliferating than on non-proliferating cells. In vivo, docetaxel is schedule-independent. Over 80% of murine transplantable tumours were found to be very docetaxel sensitive, with complete regression of advanced stage tumours. Activity was also observed in > 90% of advanced stage human tumour xenografts in mice. In combination therapy studies, synergism with 5-fluorouracil, cyclophosphamide and etoposide was observed in vivo. Docetaxel exhibited linear pharmacokinetics and long tumour retention in tumour-bearing mice; plasma protein binding ranged from 76 to 89%. In toxicological studies in mice and dogs, docetaxel produced haematological, gastrointestinal and neuromotor toxicity. The dog was found to be the most sensitive species to the toxic effects of docetaxel. PMID:7577097

Bissery, M C

1995-01-01

205

Preclinical study of using multiphoton microscopy to diagnose liver cancer and differentiate benign and malignant liver lesions  

NASA Astrophysics Data System (ADS)

Recently, the miniaturized multiphoton microscopy (MPM) and multiphoton probe allow the clinical use of multiphoton endoscopy for diagnosing cancer via ``optical biopsy''. The purpose of this study was to establish MPM optical diagnostic features for liver cancer and evaluate the sensitivity, specificity, and accuracy of MPM optical diagnosis. Firstly, we performed a pilot study to establish the MPM diagnostic features by investigating 60 surgical specimens, and found that high-resolution MPM images clearly demonstrated apparent differences between benign and malignant liver lesions in terms of their tissue architecture and cell morphology. Cancer cells, characterized by irregular size and shape, enlarged nuclei, and increased nuclear-cytoplasmic ratio, were identified by MPM images, which were comparable to hematoxylin-eosin staining images. Secondly, we performed a blinded study to evaluate the sensitivity, specificity, and accuracy of MPM optical diagnosis by investigating another 164 specimens, and found that the sensitivity, specificity, and accuracy of MPM diagnosis was 96.32%, 96.43%, and 96.34%, respectively. In conclusion, it is feasible to use MPM to diagnose liver cancer and differentiate benign and malignant liver lesions. This preclinical study provides the groundwork for further using multiphoton endoscopy to perform real-time noninvasive ``optical biopsy'' for liver lesions in the near future.

Yan, Jun; Zhuo, Shuangmu; Chen, Gang; Wu, Xiufeng; Zhou, Dong; Xie, Shusen; Jiang, Jiahao; Ying, Mingang; Jia, Fan; Chen, Jianxin; Zhou, Jian

2012-02-01

206

Toxicology and Carcinogenesis Studies of Acetaminophen (CAS No. 103-90-2) in F344/N Rats and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies were conducted by administering acetamionophen (purity > 99%) to groups of 60 F344/N rats and 50 B6C3F1 mice of each sex by feeding in diets containing 0,600,3,000, or 6,000ppm acetaminophen continuously for up to 104...

1993-01-01

207

Toxicology and Carcinogenesis Studies of Methylphenidate Hydrochloride (CAS No. 298-59-9) in F344/N Rats and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenicity studies were conducted by administration of methylphenidate hydrochloride in feed to groups of 70 F344/N rats of each sex at doses of 0, 100, 500, or 1,0000 ppm and to groups of 70 B6C3F1 mice of each sex at doses of 0, 50, ...

1995-01-01

208

Toxicology and Carcinogenesis Studies of Methyl Methacrylate (CAS NO. 80-62-6) in F344/N Rats and B6C3F1 Mice (Inhalation Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies of methyl methacrylate, a liquid chemical intermediate used in the plastics industry in the manufacture of plexiglass and other acrylic products, were conducted by exposing groups of F344/N rats and B6C3F1 mice by inh...

1986-01-01

209

Toxicology and Carcinogenesis Studies of Mercuric Chloride (CAS No. 7487-94-7) in F344 Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Two year toxicology and carcinogenicity studies were conducted by administering to groups of 60 rats of each sex 0,2.5, or 5 mg mercuric chloride/kg body weight and groups of 60 mice of each sex in 0,5, or 10 mg/kg in deionized water by gavage 5 days per ...

1993-01-01

210

Toxicology and Carcinogenesis Studies of Codeine (CAS No. 76-57-3) in F344/N Rats and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenicity studies were conducted by oral administration of codeine to groups of 60 F344/N rats of each sex at 0, 400, 800, or 1,600 ppm and 60 B6C3F1 mice of each sex at 0, 750, 1,500, or 3,000 ppm in feed for up to 106 weeks. In each...

1996-01-01

211

Toxicology and Carcinogenesis Studies of Ampicillin Trihydrate (CAS NO. 7177-48-2) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies of ampicillin trihydrate were conducted by administering the chemical in corn oil by gavage to groups of 50 F344/N rats and 50 B6C3F1 mice of each sex, 5 days per week for 103 weeks. Male and female rats rece...

1987-01-01

212

Toxicology and Carcinogenesis Studies of Furfural (CAS No. 98-01-1) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies of furfural were conducted by administering 0, 30, or 60 mg/kg furfural in corn oil by gavage to groups of 50 rats of each sex, 5 days per week for 103 weeks. Groups of 50 mice of each sex were administered 0, 50, 100...

1990-01-01

213

Toxicology and Carcinogenesis Studies of Erythromycin Stearate (CAS No. 643-22-1) in F344/N Rats and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies of erythromycin stearate were conducted by feeding diets containing 0, 5,000 or 10,000 ppm of the chemical to groups of 50 F344/N rats of each sex for 103 weeks. Diets containing O, 2,500 or 5,000 ppm were fed to grou...

1988-01-01

214

NTP Technical Report on the Toxicology and Carcinogenesis Studies of Ethylene Glycol (CAS No. 107-21-1) in B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies were conducted by administering ethylene glycol in the diet of 60 male mice (0, 6250, 12,500, or 25,000 ppm) and 60 female mice (0, 12,500, 25,000, or 50,000 ppm) for up to 103 weeks. These concentrations correspond t...

1993-01-01

215

Toxicology and Carcinogenesis Studies of Glycidol (Cas No. 556-52-5) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Glycidol is a viscous liquid that is used as a stabilizer in the manufacture of vinyl polymers, as an additive for oil and synthetic hydraulic fluids, and as a diluent in some epoxy resins. Toxicology and carcinogenesis studies were conducted by administe...

R. Irwin

1990-01-01

216

Efficacy of Pimobendan in the Prevention of Congestive Heart Failure or Sudden Death in Doberman Pinschers with Preclinical Dilated Cardiomyopathy (The PROTECT Study)  

PubMed Central

Background The benefit of pimobendan in delaying the progression of preclinical dilated cardiomyopathy (DCM) in Dobermans is not reported. Hypothesis That chronic oral administration of pimobendan to Dobermans with preclinical DCM will delay the onset of CHF or sudden death and improve survival. Animals Seventy-six client-owned Dobermans recruited at 10 centers in the UK and North America. Methods The trial was a randomized, blinded, placebo-controlled, parallel group multicenter study. Dogs were allocated in a 1:1 ratio to receive pimobendan (Vetmedin capsules) or visually identical placebo. The composite primary endpoint was prospectively defined as either onset of CHF or sudden death. Time to death from all causes was a secondary endpoint. Results The proportion of dogs reaching the primary endpoint was not significantly different between groups (P = .1). The median time to the primary endpoint (onset of CHF or sudden death) was significantly longer in the pimobendan (718 days, IQR 441–1152 days) versus the placebo group (441 days, IQR 151–641 days) (log-rank P = 0.0088). The median survival time was significantly longer in the pimobendan (623 days, IQR 491–1531 days) versus the placebo group (466 days, IQR 236–710 days) (log-rank P = .034). Conclusion and Clinical Importance The administration of pimobendan to Dobermans with preclinical DCM prolongs the time to the onset of clinical signs and extends survival. Treatment of dogs in the preclinical phase of this common cardiovascular disorder with pimobendan can lead to improved outcome.

Summerfield, NJ; Boswood, A; O'Grady, MR; Gordon, SG; Dukes-McEwan, J; Oyama, MA; Smith, S; Patteson, M; French, AT; Culshaw, GJ; Braz-Ruivo, L; Estrada, A; O'Sullivan, ML; Loureiro, J; Willis, R; Watson, P

2012-01-01

217

Preclinical Studies of the Chinese Herbal Medicine formulation PHY906 as a Potential Adjunct to Radiation Therapy  

PubMed Central

Purpose/Objectives Abdominal and pelvic radiotherapy is limited by the radiosensitivity of the small and large intestine. PHY906, a state-of-the-art adaptation of a traditional Chinese medicine, decreased intestinal injury from chemotherapy in preclinical studies and is in clinical trials with chemotherapy. This project assessed whether PHY906 would also reduce intestinal injury from whole-abdomen irradiation in mice. Materials/Methods BALB/c mice received whole-abdomen irradiation (2 Gy/day) ± PHY906 by oral gavage twice daily for 4 days. Intestinal injury was assayed by physiological observations and histological studies. Effects of PHY906 on tumor radiation response were assayed in tumor growth studies. Results PHY906 decreased the toxicity of fractionated abdominal irradiation. Radiation alone produced marked blunting and loss of villi, crypt loss, crypt hyperplasia and irregular crypt morphology, which were reduced by PHY906. The radiation-induced reduction in viable crypt counts was also mitigated by PHY906. PHY906 did not alter radiation-induced weight loss, but resulted in more rapid recovery. PHY906 did not alter growth, local invasion or metastatic spread of EMT6 mouse mammary tumors or protect tumors from growth delays produced by single-dose and fractionated irradiation. Conclusion In this mouse model system, PHY906 decreased the toxicity of abdominal irradiation, without protecting tumors, thereby increasing the therapeutic ratio.

Rockwell, Sara; Grove, Tina A.; Liu, Yanfeng; Cheng, Yung-Chi; Higgins, Susan A; Booth, Carmen J

2013-01-01

218

Comparative Plasma Exposure and Lung Distribution of Two Human Use Commercial Azithromycin Formulations Assessed in Murine Model: A Preclinical Study  

PubMed Central

Azithromycin (AZM) therapeutic failure and relapses of patients treated with generic formulations have been observed in clinical practice. The main goal of this research was to compare in a preclinical study the serum exposure and lung tissue concentration of two commercial formulations AZM-based in murine model. The current study involved 264 healthy Balb-C. Mice were divided into two groups (n = 44): animals of Group A (reference formulation -R-) were orally treated with AZM suspension at 10?mg/kg of b.w. Experimental animals of Group B (generic formulation -G-) received identical treatment than Group A with a generic formulation AZM-based. The study was repeated twice as Phase II and III. Serum and lung tissue samples were taken 24?h post treatment. Validated microbiological assay was used to determine the serum pharmacokinetic and lung distribution of AZM. After the pharmacokinetic analysis was observed, a similar serum exposure for both formulations of AZM assayed. In contrast, statistical differences (P < 0.001) were obtained after comparing the concentrations of both formulations in lung tissue, being the values obtained for AUC and Cmax (AZM-R-) +1586 and 122%, respectively, than those obtained for AZM-G- in lung. These differences may indicate large differences on the distribution process of both formulations, which may explain the lack of efficacy/therapeutic failure observed on clinical practice.

Rivulgo, Virginia; Sparo, Monica; Ceci, Monica; Fumuso, Elida; Confalonieri, Alejandra; Sanchez Bruni, Sergio F.

2013-01-01

219

Photodynamic therapy with the phthalocyanine photosensitizer Pc 4: The case experience with preclinical mechanistic and early clinical-translational studies  

SciTech Connect

Photodynamic therapy (PDT) is emerging as a promising non-invasive treatment for cancers. PDT involves either local or systemic administration of a photosensitizing drug, which preferentially localizes within the tumor, followed by illumination of the involved organ with light, usually from a laser source. Here, we provide a selective overview of our experience with PDT at Case Western Reserve University, specifically with the silicon phthalocyanine photosensitizer Pc 4. We first review our in vitro studies evaluating the mechanism of cell killing by Pc 4-PDT. Then we briefly describe our clinical experience in a Phase I trial of Pc 4-PDT and our preliminary translational studies evaluating the mechanisms behind tumor responses. Preclinical work identified (a) cardiolipin and the anti-apoptotic proteins Bcl-2 and Bcl-xL as targets of Pc 4-PDT, (b) the intrinsic pathway of apoptosis, with the key participation of caspase-3, as a central response of many human cancer cells to Pc 4-PDT, (c) signaling pathways that could modify apoptosis, and (d) a formulation by which Pc 4 could be applied topically to human skin and penetrate at least through the basal layer of the epidermis. Clinical-translational studies enabled us to develop an immunohistochemical assay for caspase-3 activation, using biopsies from patients treated with topical Pc 4 in a Phase I PDT trial for cutaneous T-cell lymphoma. Results suggest that this assay may be used as an early biomarker of clinical response.

Miller, Janine D. [Department of Dermatology, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, OH 44106 (United States); Case Skin Diseases Research Center, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, OH 44106 (United States); Case Comprehensive Cancer Center, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, OH 44106 (United States); Baron, Elma D. [Department of Dermatology, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, OH 44106 (United States); Case Skin Diseases Research Center, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, OH 44106 (United States); Case Comprehensive Cancer Center, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, OH 44106 (United States); Louis-Stokes VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106 (United States); Scull, Heather [Department of Dermatology, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, OH 44106 (United States); Case Skin Diseases Research Center, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, OH 44106 (United States); Case Comprehensive Cancer Center, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, OH 44106 (United States); Hsia, Andrew [Department of Dermatology, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, OH 44106 (United States); Berlin, Jeffrey C. [Department of Dermatology, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, OH 44106 (United States); Department of Chemistry, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, OH 44106 (United States)] (and others)

2007-11-01

220

Evaluation of rodent-only toxicology for early clinical trials with novel cancer therapeutics  

PubMed Central

Preclinical toxicology studies are performed prior to phase I trials with novel cancer therapeutics to identify a safe clinical starting dose and potential human toxicities. The primary aim of this study was to evaluate the ability of rodent-only toxicology studies to identify a safe phase I trial starting dose. In addition, the ability of murine studies to predict the quantitative and qualitative human toxicology of cancer therapeutics was studied. Data for 25 cancer drugs were collated for which the preclinical and clinical routes and schedules of administration were either the same (22/25), or closely matched. The maximum tolerated dose/dose lethal to 10% of mice (MTD/LD10) was identified for 24 drugs, and in patients the maximum administered dose (MAD) was associated with dose-limiting toxicity (DLT) in initial clinical trials with 20 compounds. In addition, for 13 agents, the toxicity of the drug at one-tenth the mouse MTD/LD10 was also investigated in rats, following repeated administration (20 doses). A phase I trial starting dose of one-tenth the mouse MTD/LD10 (mg m–2) was, or would have been, safe for all 25 compounds. With the exception of nausea and vomiting, which cannot be assessed in rodents, other common DLTs were accurately predicted by the murine studies (i.e. 7/7 haematological and 3/3 neurological DLTs). For two of the 13 drugs studied in rats, repeated administration of one-tenth the mouse MTD/LD10 was toxic, leading to a reduction in the phase I trial starting dose; however, one-tenth the mouse MTD/LD10 was subsequently tolerated in patients. For the 20 drugs where clinical DLT was reached, the median ratio of the human MAD to the mouse MTD/LD10 was 2.6 (range 0.2–16) and the median ratio of the clinical starting dose to the MAD was 35 (range 2.3–160). In contrast, in 13 subsequent phase I trials with 11 of the initial 25 drugs, the median ratio of the clinical starting dose to the MAD was 2.8 (range 1.6–56), emphasizing the value of early clinical data in rapidly defining the dose range for therapeutic studies. For all 25 drugs studied, rodent-only toxicology provided a safe and rapid means of identifying the phase I trial starting dose and predicting commonly encountered DLTs. This study has shown that the routine use of a non-rodent species in preclinical toxicology studies prior to initial clinical trials with cancer therapeutics is not necessary. © 1999 Cancer Research Campaign

Newell, D R; Burtles, S S; Fox, B W; Jodrell, D I; Connors, T A

1999-01-01

221

Systems toxicology.  

PubMed

The need for a more mechanistic understanding of the ways in which chemicals modulate biological pathways is urgent if we are to identify and better assess safety issues relating to a wide range of substances developed by the pharmaceutical, chemical, agri-bio, and cosmetic industries. Omics technologies provide a valuable opportunity to refine existing methods and provide information for so-called integrated testing strategies via the creation of signatures of toxicity. By mapping these signatures to underlying pathways of toxicity, some of which have been identified by toxicologists over the last few decades, and bringing them together with pathway information determined from biochemistry and molecular biology, a "systems toxicology" approach will enable virtual experiments to be conducted that can improve the prediction of hazard and the assessment of compound toxicity. PMID:22562485

Hartung, Thomas; van Vliet, Erwin; Jaworska, Joanna; Bonilla, Leo; Skinner, Nigel; Thomas, Russell

2012-01-01

222

Preclinical studies for pharmacokinetics and biodistribution of Ad-stTRAIL, an adenovirus delivering secretable trimeric TRAIL for gene therapy  

PubMed Central

Malignant glioma is the most frequent type in brain tumors. The prognosis of this tumor has not been significantly improved for the past decades and the average survival of patients is less than one year. Thus, an effective novel therapy is urgently needed. TNF-related apoptosis inducing ligand (TRAIL), known to have tumor cell-specific killing activity, has been investigated as a novel therapeutic for cancers. We have developed Ad-stTRAIL, an adenovirus delivering secretable trimeric TRAIL for gene therapy and demonstrated the potential to treat malignant gliomas. Currently, this Ad-stTRAIL gene therapy is under phase I clinical trial for malignant gliomas. Here, we report preclinical studies for Ad-stTRAIL carried out using rats. We delivered Ad-stTRAIL intracranially and determined its pharmacokinetics and biodistribution. Most Ad-stTRAIL remained in the delivered site and the relatively low number of viral genomes was detected in the opposite site of brain and cerebrospinal fluid. Similarly, only small portion of the viral particles injected was found in the blood plasma and major organs and tissues, probably due to the brain-blood barrier. Multiple administrations did not lead to accumulation of Ad-stTRAIL at the injection site and organs. Repeated delivery of Ad-stTRAIL did not show any serious side effects. Our data indicate that intracranially delivered Ad-stTRAIL is a safe approach, demonstrating the potential as a novel therapy for treating gliomas.

Kim, Chae-Young; Park, Soon-Hye; Jeong, Moonsup; Kwon, O-Seo; Doh, Hyounmie; Kang, Su-Hyung; Robbins, Paul D.; Kim, Byong-Moon

2011-01-01

223

Re-Evaluate the Effect of Hyperbaric Oxygen Therapy in Cancer - A Preclinical Therapeutic Small Animal Model Study  

PubMed Central

Tumor hypoxia is a known driver of angiogenesis that also facilitates tumor growth. Moreover, poorly oxygenated central tumor area remains relatively radio or chemo resistant. HBO therapy is known to elevate the levels of dissolved oxygen and eliminates tumor hypoxia. It has been one of the modalities in cancer treatment; therefore its optimization is important. In this experimental study, no cancer enhancing effect was seen during the course of HBO therapy; however, post therapy there was an accelerated growth and progression of tumor. HBO treated mice lived shorter and the response to therapy was dose & tumor volume dependent. HBO therapy probably exert its effect on the cancer proliferating cells through multiple pathways such as increased DNA damage, apoptosis & geno-toxicity leading to slow cancer progression while post therapy tumorigenic effect could be due to impaired DNA repair mechanism, mutagenic effect & aneuploidy as well as altered blood supply & nutrients. Tumor growth reached plateau with time and this finding validated theoretical model predicting tumor reaching an asymptotic limit. While, marked asymmetry observed in tumor volume progression or cancer cell proliferation rate in each of the experimental C3H mouse suggested a need for an alternate small animal pre-clinical cancer therapeutic model.

Pande, Sneha; Sengupta, Amit; Srivastava, Anurag; Gude, Rajiv P.; Ingle, Arvind

2012-01-01

224

A review of preclinical and clinical studies using synthetic materials for meniscus replacement.  

PubMed

The emerging field of tissue engineering holds the promise to use bio-materials for meniscus injury repair, namely scaffold or meniscus implant. Many implants have been studied and several studies have been conducted to verify the safety and quality of scaffolds. Preliminary data support the idea that synthetic implants can provide an alternative to menyscectomy helping to preserve the cartilage and preventing arthritis in patient with menisci injuries. However, the prevalence of postoperative complications varies within studies. Further investigations are required to evaluate the role of these materials in the clinical practice. PMID:24016324

Longo, Umile Giuseppe; Rizzello, Giacomo; Berton, Alessandra; Fumo, Caterina; Battaglia, Giulio; Khan, Wasim S; Denaro, Vincenzo

2013-11-01

225

Comparative toxicology of borates  

Microsoft Academic Search

Inorganic borates, including boric acid, Na, ammonium, K, and Zn borates generally display low acute toxicity orally, dermally,\\u000a and by inhalation. They are either not irritant or mild skin and eye irritants. Exceptions owing to physiochemical properties\\u000a do occur.\\u000a \\u000a Longer-term toxicological studies have been reported mainly on boric acid or borax where the properties are generally similar\\u000a on an equivalent

Susan A. Hubbard

1998-01-01

226

SPONTANEOUS OCCURRENCE OF A DISTINCTIVE RENAL TUBULE TUMOR PHENOTYPE IN RAT CARCINOGENICITY STUDIES CONDUCTED BY THE NATIONAL TOXICOLOGY PROGRAM (NTP)  

PubMed Central

The Toxicology Data Management System (TDMS) of the National Toxicology Program, NIEHS, NIH, was surveyed for occurrence and distribution of a distinctive renal tubule tumor type in rats. The hallmark features of this tumor included eosinophilic/amphophilic staining, large finely granular cells, and numerous vacuoles and/or minilumens. It is referred to here as the amphophilic-vacuolar (AV) variant of renal tubule tumor. Of 154 studies in which renal tubule tumors had been recorded in the standard single sections of kidney in the TDMS, there were collectively 1012 rats with renal adenomas, carcinomas or adenocarcinomas, and of these, 100 displayed the distinctive AV morphology, representing 74 studies involving mostly the F344 rat, but also the Sprague-Dawley and Wistar strains. The AV tumors (mainly adenomas but also some carcinomas) occurred usually as solitary lesions in the affected animals. However, they were multiple and bilateral in a few cases. They were equally distributed between the sexes, did not metastasize (at least to the lung), and were not associated with chronic progressive nephropathy. The distribution of this renal tumor type was random across studies and dose groups, underscoring the likelihood that it was of spontaneous origin and not chemically induced. Accordingly, it is suggested that this distinctive renal tumor phenotype be recorded as a separate category from conventional RTT when assessing the carcinogenic potential of a test compound.

Hard, Gordon C; Seely, John Curtis; Kissling, Grace E; Betz, Laura J

2010-01-01

227

Remote ischaemic preconditioning protects against cardiopulmonary bypass-induced tissue injury: a preclinical study  

Microsoft Academic Search

Objectives: To test the hypothesis that remote ischaemic preconditioning (rIPC) reduces injury after cardiopulmonary bypass (CPB).Design: Randomised study with an experimental model of CPB (3 h CPB with 2 h of cardioplegic arrest). Twelve 15 kg pigs were randomly assigned to control or rIPC before CPB and followed up for 6 h.Intervention: rIPC was induced by four 5 min cycles

R K Kharbanda; J Li; I E Konstantinov; M M H Cheung; P A White; H Frndova; J Stokoe; P Cox; M Vogel; G Van Arsdell; R MacAllister; A N Redington

2006-01-01

228

Application of micro-ct assessment of 3-d bone microstructure in preclinical and clinical studies  

Microsoft Academic Search

As the mechanical competence of trabecular bone is a function of its apparent density and 3-D distribution, assessment of\\u000a 3-D trabecular structural characteristics may improve our ability to understand the pathophysiology of osteoporosis, to test\\u000a the efficacy of pharmaceutical intervention, and to estimate bone biomechanical properties. We have studied ovariectomy-induced\\u000a osteopenia in rats and its treatment with agents such as

Yebin Jiang; Jenny Zhao; Er-Yuan Liao; Ru-Chun Dai; Xian-Ping Wu; Harry K. Genant

2005-01-01

229

Application of accelerator mass spectrometry to macromolecules: preclinical pharmacokinetic studies on a polybisphosphonate.  

PubMed

Data on the use of accelerator mass spectrometry (AMS) in conjunction with in vivo studies of macromolecular drugs are scarce. The present study shows the versatility of this technique when investigating the pharmacokinetics (PK) of a macromolecular drug candidate, a polybisphosphonate conjugate (ODX). The aforementioned is a polymer (molecular weight ~30?kDa) constituting a carbohydrate backbone with covalently linked ligands (aldendronate and aminoguanidine) and is intended for treatment of osteoporosis and the therapy of bone metastasis from prostate cancer. The conjugate is prepared through partial oxidation of the carbohydrate and sequential coupling of the ligands by reductive amination. (14)C was incorporated in the conjugate by means of coupling a commercially available (14)C-lysine in the conjugation sequence. Fifteen rats were injected intravenously with (14)C-labelled ODX (150?µg, 14?Bq/rat) and blood samples were collected at 1, 2, 4, 6, and 24?h post-injection (3 rats/time point). Liver, spleen and kidney samples were collected at 4 and 24?h post-injection. Blood from each time point (triplicate) were collected for AMS measurement determining the isotopic ratio ((14)C/(12)C) and consequently the drug concentration in blood. ODX showed a transient presence in blood circulation; 93% of the total dose was cleared from the circulation within 1?h. The half-life after 1?h was estimated to be about 3?h; 0.7% of the administered (14)C dose of ODX remained in circulation after 24?h. The major (14)C accumulation was in the liver, the spleen and the kidneys indicating the probable route of metabolism and excretion. This study demonstrates the versatility of AMS for pharmacological in vivo studies of macromolecules. Labelling with (14)C is relatively simple, inexpensive and the method requires minimal radioactivity, eliminating the need for radioprotection precautions in contrast to methods using scintillation counting. PMID:21818805

Salehpour, Mehran; Håkansson, Karl; Höglund, Urban; Grahn-Westin, Annika; Nilsson, Sten; Márquez, Marcela; Possnert, Göran; Holmberg, Anders R

2011-09-15

230

Preclinical Studies and Clinical Correlation of the Effect of Alkylating Dose1  

Microsoft Academic Search

Dose-response studies were performed with the alkylating agents (nitrogen mustard, \\/V,Ar'-bis(2-chloroethyl)-AI-nitrosourea, melphalan, cisplatin (CDDP), 4-hydroperoxycyclophosphamide (4-HC), and tri- methyleneiminethiophosphoramide) in both the MCF-7 human breast carcinoma cell line and the EMT6 and FSalIC murine tumor lines. Increasing selection pressure with the alkylating agents CDDP, mel phalan, and 4-HC In vitro produced low levels (6.5- to 9-fold) of drug resistance, despite

Emil Frei; Beverly A. Teicher; Sylvia A. Holden; Kathleen N. S. Cathcart; Yenyun Wang

1988-01-01

231

A Preclinical and Clinical Study of Lithium in Low-Grade Neuroendocrine Tumors  

PubMed Central

Background. Low-grade neuroendocrine tumors (NETs) respond poorly to chemotherapy; effective, less toxic therapies are needed. Glycogen synthase kinase (GSK)-3? has been shown to regulate growth and hormone production in NETs. Use of lithium chloride in murine models suppressed carcinoid cell growth, reduced GSK-3? levels, and reduced expression of chromogranin A. This study assessed the efficacy of lithium chloride in patients with NETs. Design. Eligible patients had low-grade NETs. A single-arm, open-label phase II design was used. Lithium was dosed at 300 mg orally three times daily, titrated to serum levels of 0.8–1.0 mmol/L. The primary endpoint was objective tumor response by the Response Evaluation Criteria in Solid Tumors. Secondary endpoints included overall survival, progression-free survival, GSK-3? phosphorylation, and toxicity. Results. Fifteen patients were enrolled between October 3, 2007 and July 17, 2008, six men and nine women. The median age was 58 years. Patient diagnoses were carcinoid tumor for eight patients, islet cell tumor for five patients, and two unknown primary sites. Eastern Cooperative Oncology Group performance status scores were 0 or 1. Two patients came off study because of side effects. The median progression-free survival interval was 4.50 months. There were no radiographic responses. Because of an early stopping rule requiring at least one objective response in the first 13 evaluable patients, the study was closed to further accrual. Patients had pre- and post-therapy biopsies. Conclusions. Lithium chloride was ineffective at obtaining radiographic responses in our 13 patients who were treated as part of this study. Based on the pre- and post-treatment tumor biopsies, lithium did not potently inhibit GSK-3? at serum levels used to treat bipolar disorders.

Kunnimalaiyaan, Muthusamy; Holen, Kyle D.; Ning, Li; Ndiaye, Mary; LoConte, Noelle K.; Mulkerin, Daniel L.; Schelman, William R.; Chen, Herbert

2011-01-01

232

AAV-Mediated Gene Therapy for Choroideremia: Preclinical Studies in Personalized Models  

PubMed Central

Choroideremia (CHM) is an X- linked retinal degeneration that is symptomatic in the 1st or 2nd decade of life causing nyctalopia and loss of peripheral vision. The disease progresses through mid-life, when most patients become blind. CHM is a favorable target for gene augmentation therapy, as the disease is due to loss of function of a protein necessary for retinal cell health, Rab Escort Protein 1 (REP1).The CHM cDNA can be packaged in recombinant adeno-associated virus (rAAV), which has an established track record in human gene therapy studies, and, in addition, there are sensitive and quantitative assays to document REP1 activity. An animal model that accurately reflects the human condition is not available. In this study, we tested the ability to restore REP1 function in personalized in vitro models of CHM: lymphoblasts and induced pluripotent stems cells (iPSCs) from human patients. The initial step of evaluating safety of the treatment was carried out by evaluating for acute retinal histopathologic effects in normal-sighted mice and no obvious toxicity was identified. Delivery of the CHM cDNA to affected cells restores REP1 enzymatic activity and also restores proper protein trafficking. The gene transfer is efficient and the preliminary safety data are encouraging. These studies pave the way for a human clinical trial of gene therapy for CHM.

Vasireddy, Vidyullatha; Kohnke, Monika; Black, Aaron D.; Alexandrov, Krill; Zhou, Shangzhen; Maguire, Albert M.; Chung, Daniel C.; Mac, Helen; Sullivan, Lisa; Gadue, Paul; Bennicelli, Jeannette L.; French, Deborah L.; Bennett, Jean

2013-01-01

233

Neural stem cell-mediated enzyme/prodrug therapy for glioma: preclinical studies.  

PubMed

High-grade gliomas are extremely difficult to treat because they are invasive and therefore not curable by surgical resection; the toxicity of current chemo- and radiation therapies limits the doses that can be used. Neural stem cells (NSCs) have inherent tumor-tropic properties that enable their use as delivery vehicles to target enzyme/prodrug therapy selectively to tumors. We used a cytosine deaminase (CD)-expressing clonal human NSC line, HB1.F3.CD, to home to gliomas in mice and locally convert the prodrug 5-fluorocytosine to the active chemotherapeutic 5-fluorouracil. In vitro studies confirmed that the NSCs have normal karyotype, tumor tropism, and CD expression, and are genetically and functionally stable. In vivo biodistribution studies demonstrated NSC retention of tumor tropism, even in mice pretreated with radiation or dexamethasone to mimic clinically relevant adjuvant therapies. We evaluated safety and toxicity after intracerebral administration of the NSCs in non-tumor-bearing and orthotopic glioma-bearing immunocompetent and immunodeficient mice. We detected no difference in toxicity associated with conversion of 5-fluorocytosine to 5-fluorouracil, no NSCs outside the brain, and no histological evidence of pathology or tumorigenesis attributable to the NSCs. The average tumor volume in mice that received HB1.F3.CD NSCs and 5-fluorocytosine was about one-third that of the average volume in control mice. On the basis of these results, we conclude that combination therapy with HB1.F3.CD NSCs and 5-fluorocytosine is safe, nontoxic, and effective in mice. These data have led to approval of a first-in-human study of an allogeneic NSC-mediated enzyme/prodrug-targeted cancer therapy in patients with recurrent high-grade glioma. PMID:23658244

Aboody, Karen S; Najbauer, Joseph; Metz, Marianne Z; D'Apuzzo, Massimo; Gutova, Margarita; Annala, Alexander J; Synold, Timothy W; Couture, Larry A; Blanchard, Suzette; Moats, Rex A; Garcia, Elizabeth; Aramburo, Soraya; Valenzuela, Valerie V; Frank, Richard T; Barish, Michael E; Brown, Christine E; Kim, Seung U; Badie, Behnam; Portnow, Jana

2013-05-01

234

Correlating preclinical animal studies and human clinical trials of a multifunctional, polymeric nanoparticle  

PubMed Central

Nanoparticles are currently being investigated in a number of human clinical trials. As information on how nanoparticles function in humans is difficult to obtain, animal studies that can be correlative to human behavior are needed to provide guidance for human clinical trials. Here, we report correlative studies on animals and humans for CRLX101, a 20- to 30-nm-diameter, multifunctional, polymeric nanoparticle containing camptothecin (CPT). CRLX101 is currently in phase 2 clinical trials, and human data from several of the clinical investigations are compared with results from multispecies animal studies. The pharmacokinetics of polymer-conjugated CPT (indicative of the CRLX101 nanoparticles) in mice, rats, dogs, and humans reveal that the area under the curve scales linearly with milligrams of CPT per square meter for all species. Plasma concentrations of unconjugated CPT released from CRLX101 in animals and humans are consistent with each other after accounting for differences in serum albumin binding of CPT. Urinary excretion of polymer-conjugated CPT occurs primarily within the initial 24 h after dosing in animals and humans. The urinary excretion dynamics of polymer-conjugated and unconjugated CPT appear similar between animals and humans. CRLX101 accumulates into solid tumors and releases CPT over a period of several days to give inhibition of its target in animal xenograft models of cancer and in the tumors of humans. Taken in total, the evidence provided from animal models on the CRLX101 mechanism of action suggests that the behavior of CRLX101 in animals is translatable to humans.

Eliasof, Scott; Lazarus, Douglas; Peters, Christian G.; Case, Roy I.; Cole, Roderic O.; Hwang, Jungyeon; Schluep, Thomas; Chao, Joseph; Lin, James; Yen, Yun; Han, Han; Wiley, Devin T.; Zuckerman, Jonathan E.; Davis, Mark E.

2013-01-01

235

A method for obtaining randomized block designs in preclinical studies with multiple quantitative blocking variables.  

PubMed

A method is proposed for block randomization of treatments to experimental units that can accommodate both multiple quantitative blocking variables and unbalanced designs. Hierarchical clustering in conjunction with leaf-order optimization is used to block experimental units in multivariate space. The method is illustrated in the context of a diabetic mouse assay. A simulation study is presented to explore the utility of the proposed randomization method relative to that of a completely randomized approach, both in the presence and absence of covariate adjustment. An example R function is provided to illustrate the implementation of the method. PMID:20572260

Iturria, Stephen J

236

Novel sugar esters proniosomes for transdermal delivery of vinpocetine: preclinical and clinical studies.  

PubMed

Vinpocetine (Vin) existing oral formulations suffer poor bioavailability (?7%) since Vin undergoes a marked first-pass effect (?75%) and its absorption is dissolution rate-limited. In this study, a novel sustained release proniosomal system was designed using sugar esters (SEs) as non-ionic surfactants in which proniosomes were converted to niosomes upon skin water hydration following topical application under occlusive conditions. Different in vitro aspects (encapsulation efficiency, vesicle size and shape, effect of occlusion, in vitro release, skin permeation and stability) were studied leading to an optimized formula that was assessed clinically for transdermal pharmacokinetics and skin irritation. All formulae exhibited high entrapment efficiencies, regardless of the surfactant HLB. Vesicle size analysis showed that all vesicles were in the range from 0.63 ?m to 2.52 ?m which favored efficient transdermal delivery. The extent of drug permeation through the skin from the optimized formula--containing laurate SE with shorter fatty acid chain length and high HLB--was quite high (91%) after 48 h under occlusive conditions. The extent of absorption of Vin from proniosomes was larger when compared to the oral tablet with a relative bioavailability (F(rel)) of 206%. Histopathological evaluation revealed only moderate skin irritation when using SEs compared to skin inflammation when using Tween 80. Sugar esters proniosomes may be a promising carrier for vinpocetine, especially due to their simple scaling up and their ability to control drug release. PMID:21056658

El-Laithy, Hanan M; Shoukry, Omar; Mahran, Laila G

2010-11-05

237

Evaluation of wound healing activity of Lantana camara L. - a preclinical study.  

PubMed

Lantana camara is used in herbal medicine for the treatment of skin itches, as an antiseptic for wounds, and externally for leprosy and scabies. The objective of our study was to investigate excision wound healing activity of the leaf extract of L. camara in rats. The animals were divided into two groups of 12 each in both the models. The test group animals were treated with the aqueous extract of L. camara (100 mg/kg/day) topically and the control group animals were left untreated. Wound healing efficacy was measured by determining the morphological and biochemical parameters. Wound healing time, wound contraction and synthesis of collagen were monitored periodically. Antimicrobial activities of the extract against the microorganisms were also assessed. Treatment of the wounds with extract enhanced significantly the rate of wound contraction (98%), synthesis of collagen and decreased mean wound healing time. These studies demonstrate that L. camara is effective in healing excision wounds in the experimental animal and could be evaluated as a therapeutic agent in tissue repair processes associated with skin injuries. PMID:18844241

Nayak, B Shivananda; Raju, S Sivachandra; Eversley, Mathew; Ramsubhag, Adash

2009-02-01

238

NMR-based metabolomic studies on the toxicological effects of cadmium and copper on green mussels Perna viridis.  

PubMed

Traditional toxicology studies have focused on selected biomarkers to characterize the biological stress induced by metals in marine organisms. In this study, a system biology tool, metabolomics, was applied to the marine mussel Perna viridis to investigate changes in the metabolic profiles of soft tissue as a response to copper (Cu) and cadmium (Cd), both as single metal and as a mixture. The major metabolite changes corresponding to metal exposure are related to amino acids, osmolytes, and energy metabolites. Following metal exposure for 1 week, there was a significant increase in the levels of branched chain amino acids, histidine, glutamate, glutamine, hypotaurine, dimethylglycine, arginine and ATP/ADP. For the Cu+Cd co-exposed mussels, the levels of lactate, branched chain amino acid, succinate, and NAD increased, whereas the levels of glucose, glycogen, and ATP/ADP decreased, indicating a different metabolic profile for the single metal exposure groups. After 2 weeks of exposure, the mussels showed acclimatization to Cd exposure based on the recovery of some metabolites. However, the metabolic profile induced by the metal mixture was very similar to that from Cu exposure, suggesting that Cu dominantly induced the metabolic disturbances. Both Cu and Cd may lead to neurotoxicity, disturbances in energy metabolism, and osmoregulation changes. These results demonstrate the high applicability and reliability of NMR-based metabolomics in interpreting the toxicological mechanisms of metals using global metabolic biomarkers. PMID:20843565

Wu, Huifeng; Wang, Wen-Xiong

2010-08-24

239

A preclinical study of the effects of seabuckthorn (Hippophae rhamnoides L.) leaf extract on cutaneous wound healing in albino rats.  

PubMed

Hippophae rhamnoides L. (family Elaeagnaceae), commonly known as seabuckthorn, is a wild shrub growing at high altitude (1200-4500 meters) in adverse climatic conditions. The aim of the present study was to evaluate healing potential of seabuckthorn leaves in a preclinical study on rats using a cutaneous excision-punch wound model. Four full-thickness excision-type wounds of 8.0 mm diameter were created on the dorsal surface of rats under aseptic conditions. The aqueous lyophilized extract of seabuckthorn leaves, at doses of 0.5%, 1.0%, and 1.5% w/v prepared in propylene glycol, were applied topically twice daily for 7 days. Control animals received the vehicle alone in an identical manner. Wound granulation tissues were excised on eighth day postwounding, and the hydroxyproline, hexosamine, total protein content, and antioxidant levels were determined. Wound surface area was also measured on the eighth day before wound excision to determine wound contraction. Topical application of 1.0% seabuckthorn leaf extract statistically significantly augmented the healing process, as evidenced by increases in the content of hydroxyproline and protein as well as the reduction in wound area when compared with similar effects in response to treatment using povidone-iodine ointment (standard care). The reduced glutathione, vitamin C, superoxide dismutase, catalase, and glutathione peroxidase activities showed significant increases in seabuckthorn leaf extract-treated wounds as compared to controls. The lipid peroxide levels were significantly decreased in leaf extract-treated wounds. The results suggest that aqueous leaf extract of seabuckthorn promotes wound healing, which may be due to increased antioxidant levels in the granulation tissue. PMID:15911921

Gupta, Asheesh; Kumar, Ratan; Pal, Karan; Banerjee, Pratul K; Sawhney, Ramesh C

2005-06-01

240

Systematic Approach to Remediation in Basic Science Knowledge for Preclinical Students: A case study  

NASA Astrophysics Data System (ADS)

Remediation of pre-clerkship students for deficits in basic science knowledge should help them overcome their learning deficiencies prior to clerkship. However, very little is known about remediation in basic science knowledge during pre-clerkship. This study utilized the program theory framework to collect and organize mixed methods data of the remediation plan for pre-clerkship students who failed their basic science cognitive examinations in a Canadian medical school. This plan was analyzed using a logic model narrative approach and compared to literature on the learning theories. The analysis showed a remediation plan that was strong on governance and verification of scores, but lacked: clarity and transparency of communication, qualified remedial tutors, individualized diagnosis of learner's deficits, and student centered learning. Participants admitted uncertainty about the efficacy of the remediation process. A remediation framework is proposed that includes student-centered participation, individualized learning plan and activities, deliberate practice, feedback, reflection, and rigorous reassessment.

Amara, Francis

241

Irinotecan delivery by microbubble-assisted ultrasound - A pilot preclinical study  

NASA Astrophysics Data System (ADS)

Irinotecan is conventionally used for the treatment of colorectal cancer. However, its administration is associated with severe side effects. Targeted drug delivery using ultrasound (US) combined with microbubbles offers new opportunities to increase the therapeutic effectiveness of antitumor treatment and to reduce toxic exposure to healthy tissues. The objective of this study is to investigate the safety and efficacy of in-vivo delivery of irinotecan by microbubble-assisted US in human glioblastoma model (U-87 MG). In order to validate the potential of this new method in-vivo, subcutaneous tumors were implanted in the flank of nude mouse and treated when they reached a volume of 100 mm3. In the first study, the measured volumes with caliper and anatomic ultrasound imaging were compared for the monitoring and the quantification of tumor growth during 27 days. Ultrasound imaging measurements were positively correlated to caliper measurements. The tumor treatment consisted of an i.v. injection of irinotecan (20 mg/kg) followed one hour later by i.v. administration of MM1 microbubble and an US insonation using a single-element transducer operating at 1MHz (400 kPa, 10 kHz PRF 40% DC, 3 min). The therapeutic efficacy was evaluated for 39 days by measuring the tumor volume before and after treatment using a caliper and based on ultrasound images using an 18 MHz probe (Vevo 2100). Our results showed that anatomical ultrasound imaging was as efficient as caliper for the monitoring and the quantification of tumor growth. Moreover, irinotecan delivery by sonoporation induced a significant decrease of glioblastoma tumor volume and an increase of tumor-doubling time compared to the tumor treated by irinotecan alone. In conclusion, this novel therapeutic approach has promising features since it can be used to reduce the injected drug dose and to achieve a better therapeutic efficacy.

Escoffre, Jean-Michel; Novell, Anthony; Serrière, Sophie; Bouakaz, Ayache

2012-11-01

242

Preclinical Dose-Finding Study With a Liver-Tropic, Recombinant AAV2\\/8 Vector in the Mouse Model of Galactosialidosis  

Microsoft Academic Search

Galactosialidosis (GS) is a lysosomal storage disease linked to deficiency of the protective protein\\/cathepsin A (PPCA). Similarly to GS patients, Ppca-null mice develop a systemic disease of the reticuloendothelial system, affecting most visceral organs and the nervous system. Symptoms include severe nephropathy, visceromegaly, infertility, progressive ataxia, and shortened life span. Here, we have conducted a preclinical, dose-finding study on a

Huimin Hu; Elida Gomero; Erik Bonten; John T Gray; Jim Allay; Yanan Wu; Jianrong Wu; Christopher Calabrese; Arthur Nienhuis; Alessandra d'Azzo

2012-01-01

243

Synthesis, characterization and preclinical studies of two-photon-activated targeted PDT therapeutic triads  

NASA Astrophysics Data System (ADS)

Photodynamic therapy (PDT) continues to evolve into a mature clinical treatment of a variety of cancer types as well as age-related macular degeneration of the eye. However, there are still aspects of PDT that need to be improved in order for greater clinical acceptance. While a number of new PDT photo-sensitizers, sometimes referred to as second- or third- generation therapeutic agents, are currently under clinical investigation, the direct treatment through the skin of subcutaneous tumors deeper than 5 mm remains problematic. Currently approved PDT porphyrin photo-sensitizers, as well as several modified porphyrins (e.g. chlorins, bacteriochlorins, etc.) that are under clinical investigation can be activated at 630-730 nm, but none above 800 nm. It would be highly desirable if new PDT paradigms could be developed that would allow photo-activation deep in the tissue transparency window in the Near-infrared (NIR) above 800 nm to reduce scattering and absorption phenomena that reduce deep tissue PDT efficacy. Rasiris and MPA Technologies have developed new porphyrins that have greatly enhanced two-photon absorption ( P A ) cross-sections and can be activated deep in the NIR (ca. 780-850 nm). These porphyrins can be incorporated into a therapeutic triad that also employs an small molecule targeting agent that directs the triad to over-expressed tumor receptor sites, and a NIR onephoton imaging agent that allows tracking the delivery of the triad to the tumor site, as well as clearance of excess triad from healthy tissue prior to the start of PDT treatment. We are currently using these new triads in efficacy studies with a breast cancer cell line that has been transfected with luciferase genes that allow implanted tumor growth and post- PDT treatment efficacy studies in SCID mouse models by following the rise and decay of the bioluminescence signal. We have also designed highly absorbing and scattering collagen breast cancer phantoms in which we have demonstrated dramatic cell kill to a depth of at least 4 cm. We have also demonstrated that at the wavelength and laser fluences used in the treatment of implanted tumors in the mouse mammary fat pads, there is little, if any, damage to the skin or internal mouse organs. In addition, we have also demonstrated that the implanted tumors can be treated to a depth of more than 1 cm by direct radiation through the dorsal side of the mouse.

Spangler, C. W.; Starkey, J. R.; Rebane, A.; Meng, F.; Gong, A.; Drobizhev, M.

2006-03-01

244

A novel injectable bioactive bone cement for spinal surgery: a developmental and preclinical study.  

PubMed

The injection of bone cement by minimally invasive techniques for the treatment of vertebral body fractures or for stabilization of an osteoporotic vertebral body is regarded as promising in spinal surgery. The purpose of this study was to develop a novel injectable bioactive bone cement to address such concerns. The cement was composed mainly of strontium-containing hydroxyapatite (Sr-HA) filler and Bisphenol A Diglycidylether Dimethacrylate (D-GMA) resin. The Sr-HA filler was prepared by precipitation and calcination, then analyzed with Fourier transform infrared (FTIR) spectra and X-ray diffraction (XRD) patterns. Samples of strontium-containing hydroxyapatite cement (SrHAC) were formed by a combination of powder filler and resin matrix, with the setting time and peak temperature recorded. Cell relative growth rate (RGR), Tetrazolium bromide (MTT), and haemolysis tests were used to detect initial in vitro biocompatibility of the new cement. In vitro spinal biomechanical testing and morphological observation after bone cement injection were performed on pig spines. Results indicate that the setting time and peak temperature of the cement was 15 min and 55 degrees C, respectively. Cytotoxicity of the cement was class 1 (no cytotoxicity) and haemolysis was 1% (no haemolysis). Stiffness after cement injection and fatigue loading were 112% and 95% of the intact bone, respectively, which is similar to that of natural bone. Radiopacity of SrHAC allowed easy radiographic imaging. The use of SrHAC cement is, thus, promising in spinal surgery. PMID:10906688

Li, Y W; Leong, J C; Lu, W W; Luk, K D; Cheung, K M; Chiu, K Y; Chow, S P

2000-10-01

245

Preclinical studies with zoledronic acid and other bisphosphonates: impact on the bone microenvironment.  

PubMed

The propensity for breast cancer cells to metastasize to bone and to induce osteolysis has long been recognized. Characteristics of both the tumor cells and the bone microenvironment contribute to this phenomenon. The presence of tumor in bone is associated with activation of osteoclasts, resulting in excessive bone resorption and subsequent osteolysis. Breast cancer cells and other tumor types influence osteoclastic bone resorption by increasing the number of osteoclasts and enhancing their resorptive activity. Parathyroid hormone-related peptide, in addition to its role in humorally mediated hypercalcemia, is secreted by metastatic breast cancer cells in bone in which it acts as a paracrine factor to stimulate osteoclasts. As bone matrix is broken down by activated osteoclasts, a rich supply of mitogenic factors is released, including insulin-like growth factors, bone morphogenetic proteins, and fibroblast growth factors. Transforming growth factor (TGF)-beta, one of the most abundant of the bone-derived factors, promotes increased production of parathyroid hormone-related peptide by tumor cells, establishing a "vicious cycle" leading to progressive tumor growth and bone destruction. Bisphosphonates interrupt this cycle by inhibiting osteoclasts, in part by inducing osteoclast apoptosis. In several animal models of breast cancer metastasis to bone, bisphosphonates decrease the number of new bone metastases and inhibit progression of existing lesions. A single 3 microg intravenous injection of zoledronic acid (Zometa; Novartis Pharmaceuticals Corp, East Hanover, NJ), a new highly potent bisphosphonate, prevented destruction of trabecular bone in an orthotopic mouse mammary tumor model. Tumor volume in bone was decreased by zoledronic acid in a dose-dependent manner in the same model, and tumor cell apoptosis was increased by zoledronic acid in bone metastases in the 4T1 murine model of mammary carcinoma metastasis. Zoledronic acid at a dose of 1.0 microg/d for 10 days also reduced bone lesion area in a nude mouse model with existing bone metastases. Although bisphosphonates, including zoledronic acid, are able to induce apoptosis in tumor cells in vitro, studies in animal models to date have generally not shown a reduction in nonosseous tumor. Therefore, bisphosphonate-associated tumor reduction in bone is most likely mediated by osteoclast inhibition or is related to high local concentrations of bisphosphonates in the bone compartment. PMID:11346863

Mundy, G R; Yoneda, T; Hiraga, T

2001-04-01

246

Preclinical studies of molecular-targeting diagnostic and therapeutic strategies against breast cancer.  

PubMed

We have investigated protein kinase C (PKC) signaling, a putative differentiation-related and metastasis suppressor gene Cap43/NDRG1/Drg-1, and Y-box binding protein-1 (YB-1) to identify new molecular targeting for breast cancer. PKC is a family of serine/threonine kinases that is involved in the regulation of cell growth. We have demonstrated that PKC caused G(1) arrest in a breast cancer cell line through a mechanism involving a PKC-ERK MAPK-JNK-Rb protein signaling pathway. We have also characterized a novel mechanism through which all-trans retinoic acid (ATRA) and antineoplaston, anticancer drug, caused cell growth inhibition in breast cancer cells through effects on intracellular pathways. ATRA decreased the expression of PKCalpha, as well as reduced ERK MAPK phosphorylation, and consequently caused G(1) arrest. Antineoplaston caused the down-regulation of PKCalpha protein expression, resulting in inhibition of ERK MAPK phosphorylation, with resultant inhibition of Rb phosphorylation leading to G(1) arrest. PKC signaling represents a promising target for development of novel therapeutic agents. Cap43 is known as N-myc downstream-regulated gene 1 (NDRG1). Treatment with estradiol (E(2)) significantly decreased the expression of Cap43 in ER-alpha-positive breast cancer cell lines. Co-administration of tamoxifen abrogated the E(2)-induced downregulation of Cap43 in ER-alpha-positive cell lines. These results suggested that Cap43 may hold the potential of being a molecular marker to determine the therapeutic efficacy of anti-estrogenic anticancer agents in breast cancer. YB-1 is a member of the cold shock domain protein family. The expression of nuclear YB-1 was correlated with HER2 positively in clinical specimens of human breast cancer. Immunostaining studies showed that nuclear YB-1 expression was an independent prognostic factor of overall survival. Expression of nuclear YB-1 played an essential role in acquirement of malignant characteristics through HER2-dependent pathways in breast cancer patients. PKC, Cap43 and YB-1 may be useful in new molecular-targeting diagnosis and therapeutics in breast cancer. PMID:18224398

Fujii, Teruhiko; Yokoyama, Goro; Takahashi, Hiroki; Namoto, Roka; Nakagawa, Shino; Toh, Uhi; Kage, Masayoshi; Shirouzu, Kazuo; Kuwano, Michihiko

2008-01-01

247

Monte Carlo simulation on pre-clinical irradiation: A heterogeneous phantom study on monoenergetic kilovoltage photon beams  

NASA Astrophysics Data System (ADS)

This study investigated radiation dose variations in pre-clinical irradiation due to the photon beam energy and presence of tissue heterogeneity. Based on the same mouse computed tomography image dataset, three phantoms namely, heterogeneous, homogeneous and bone homogeneous were used. These phantoms were generated by overriding the relative electron density of no voxel (heterogeneous), all voxel (homogeneous) and the bone voxel (bone homogeneous) to one. 360° photon arcs with beam energies of 50 - 1250 keV were used in mouse irradiations. Doses in the above phantoms were calculated using the EGSnrc-based DOSXYZnrc code through the DOSCTP. Monte Carlo simulations were carried out in parallel using multiple nodes in a high-performance computing cluster. It was found that the dose conformity increased with the increase of the photon beam energy from the keV to MeV range. For the heterogeneous mouse phantom, increasing the photon beam energy from 50 keV to 1250 keV increased seven times the dose deposited at the isocenter. For the bone dose enhancement, the mean dose was 2.7 times higher when the bone heterogeneity was not neglected using the 50 keV photon beams in the mouse irradiation. Bone dose enhancement affecting the mean dose was found in the photon beams with energy range of 50 - 200 keV and the dose enhancement decreased with an increase of the beam energy. Moreover, the MeV photon beam had a higher dose at the isocenter, and a better dose conformity compared to the keV beam.

Chow, James C. L.

2012-10-01

248

7?-methyl-19-nortestosterone vs. testosterone implants for hypogonadal osteoporosis: a preclinical study in the aged male orchidectomized rat model.  

PubMed

Overt male hypogonadism induces not only osteoporosis but also unfavourable changes in body composition, which can be prevented by testosterone (T) replacement. In this preclinical study, the potential of synthetic androgen 7?-methyl-19-nortestosterone (MENT) as alternative treatment for male hypogonadism was evaluated in comparison with T. Eleven-month-old male rats were orchidectomized (orch) and left untreated for 2-months. Subsequently, the effects of 4-month MENT (12 ?g/day) and T (72 ?g/day) treatment on bone, muscle and fat were analysed using microcomputed tomography, dual-energy X-ray absorptiometry, dynamic bone histomorphometry and muscle fibre typing. At the onset of treatment, orch rats were clearly hypogonadal. This was evidenced by significant reductions of androgen-sensitive organ weight, lean mass, cortical thickness and trabecular bone volume compared with sham-operated aged-matched controls (sham). MENT and T restored weight of androgen-sensitive organs to a similar extent, with a superior anabolic action of MENT on levator ani muscle. Both androgens not only fully rescued hypogonadal loss of lean mass but also restored muscle fibre type composition and trabecular bone volume. Cortical bone loss was similarly prevented by MENT and T, but without full recovery to sham. Both androgens stimulated periosteal bone formation, but with a stronger effect of T. By contrast, MENT more strongly suppressed endocortical bone formation and bone turnover rate and reduced fat mass and serum leptin to a greater extent than T. MENT and T are both effective replacement therapies to stimulate bone and muscle in hypogonadal rats, with stronger lipolytic action of MENT. PMID:21790658

Sinnesael, M; Callewaert, F; Morreels, M; Kumar, N; Sitruk-Ware, R; Van Proeyen, K; Hespel, P; Boonen, S; Claessens, F; Vanderschueren, D

2011-07-26

249

Education Predicts Incidence of Preclinical Mobility Disability in Initially High-Functioning Older Women. The Women's Health and Aging Study II  

PubMed Central

Background. To examine the impact of educational attainment on the incidence of preclinical mobility disability (PCD). Methods. The Women's Health and Aging II Study is a prospective observational cohort study of 436 initially high-functioning community-dwelling women aged 70–79 years at baseline in Baltimore, Maryland. We measured the association of highest attained education level with preclinical mobility disability (PCD) over an 11-year period. PCD is defined as self-reported modification in any of four tasks without reporting difficulty in those tasks. The tasks were walking ½ mile, climbing up steps, doing heavy housework, and getting in/out of bed or chair. Results. Participants with less than 9 years of education were more likely to acquire incident PCD (hazard ratio: 3.1, 95% confidence interval = 1.2–7.7) than their counterparts with more education after adjusting for income, marital status, number of diseases, and high self-efficacy. Conclusions. Lower education level is an independent predictor of incident preclinical mobility disability. This association has important implications for primary and secondary prevention and can be easily assessed in clinical encounters.

Gregory, Patricia C.; Xue, Qian-Li; Tian, Jing; Thorpe, Roland J.; Fried, Linda P.

2011-01-01

250

Toxicological approaches to complex mixtures.  

PubMed Central

This paper reviews the role of toxicological studies in understanding the health effects of environmental exposures to mixtures. The approach taken is to review mixtures that have received the greatest emphasis from toxicology; major mixtures research programs; the toxicologist's view of mixtures and approaches to their study; and the complementary roles of toxicological, clinical, and epidemiological studies. Studies of tobacco smoke, engine exhaust, combustion products, and air pollutants comprise most of the past research on mixtures. Because of their great experimental control over subjects, exposures, and endpoints, toxicologists tend to consider a wider range of toxic interactions among mixture components and sequential exposures than is practical for human studies. The three fundamental experimental approaches used by toxicologists are integrative (studying the mixture as a whole), dissective (dissecting a mixture to determine causative constituents), and synthetic (studying interactions between agents in simple combinations). Toxicology provides information on potential hazards, mechanisms by which mixture constituents interact to cause effects, and exposure dose-effect relationships; but extrapolation from laboratory data to quantitative human health risks is problematic. Toxicological, clinical, and epidemiological approaches are complementary but are seldom coordinated. Fostering synergistic interactions among the disciplines in studying the risks from mixtures could be advantageous.

Mauderly, J L

1993-01-01

251

Toxicological Profile for Perchlorates.  

National Technical Information Service (NTIS)

This ATSDR toxicological profile succinctly characterizes the toxicologic and adverse health effects information for the hazardous substance described therein. Each peer-reviewed profile identifies and reviews the key literature that describes a hazardous...

2008-01-01

252

Studies on the metabolism and the toxicological analysis of the nootropic drug fipexide in rat urine using gas chromatography–mass spectrometry  

Microsoft Academic Search

Qualitative studies are described on the metabolism and the toxicological analysis of the nootropic fipexide (FIP) in rat urine using gas chromatography–mass spectrometry (GC–MS). FIP was extensively metabolized to 1-(3,4-methylenedioxybenzyl)piperazine (MDBP), 4-chlorophenoxyacetic acid, 1-[2-(4-chlorophenoxy)acetyl]piperazine, N-(4-hydroxy-3-methoxy-benzyl)piperazine, piperazine, N-(3,4-methylenedioxybenzyl)ethylenediamine, and N-[2-(4-chlorophenoxy)acetyl]ethylenediamine. The authors’ systematic toxicological analysis (STA) procedure using full-scan GC–MS after acid hydrolysis of one urine aliquot, liquid-liquid extraction and acetylation

Roland F. Staack; Hans H. Maurer

2004-01-01

253

Predicting Neurotoxicity and Behavioral Dysfunction from Preclinical Toxicologic Data.  

National Technical Information Service (NTIS)

The report includes seven commissioned review papers and a workshop review of current information on neurotoxicity and behavioral dysfunction. Available basic research, test methods for detecting neurobehavioral toxicity, and the need for expanding applie...

R. W. Leukroth

1986-01-01

254

Genetic toxicology assessment of HI-6 dichloride  

SciTech Connect

The oxime HI-6 dichloride (1-(2 hydroxyiminomethyl- 1-pyridino)-3- (4-carbamoyl-1- pyridino)-2-oxapropane dichloride monohydrate) has shown to be a potent reactivator of cholinesterase activity and may have efficacy for the treatment of organo-phosphate intoxication (SIPRI, 1976; Schenk et al.; Arch Toxicol 36:71-81, 1976). As part of a pre-clinical safety assessment program, the genetic toxicology of HI-6 dichloride was evaluated in a series of assays designed to measure induction of gene mutations and chromosomal aberrations. HI-6 dichloride gave negative responses in the Salmonella mutagenicity assay and in the CHO/HGPRT gene mutation assay. Dose-dependent increases in the frequency of chromosomal aberrations when HI-6 dichloride was tested in cultured CHO cells and in cultured human peripheral blood lymphocytes. The mouse lymphoma gene mutation assay, reputed to measure both gene mutations and chromosomal deletions, was negative in the absence of metabolic activation. Depending on the criteria employed, a negative or equivocal response was seen in the presence of rat liver-derived S-9 mix. An in vivo rat bone marrow metaphase assay performed to further investigate the in vitro clastogenic responses was negative. The results from these studies indicate that HI-6 dichloride does not induce gene mutations in vitro; however, it is clastogenic in vitro but does not appear to be clastogenic in vivo.

Putman, D.; San, R.H.; Bigger, C.A.; Levine, B.S.; Jacobson-Kram, D.

1996-08-01

255

TOXNET (TOXICOLOGY DATA NETWORK)  

EPA Science Inventory

TOXNET (Toxicology Data Network) is a computerized system of files oriented to toxicology and related areas. It is managed by the National Library of Medicines Toxicology and Environmental Health Information Program (TEHIP) and runs on a series of microcomputers in a networked cl...

256

CAVEATS REGARDING THE USE OF THE LABORATORY RATS AS A MODEL FOR ACUTE TOXICOLOGICAL STUDIES: MODULATION OF THE TOXIC RESPONSE VIA PHYSIOLOGICAL AND BEHAVIORAL MECHANISMS  

EPA Science Inventory

The rodent, specifically the inbred laboratory rat, is the primary experimental animal used in toxicology testing. Despite its popularity, recent studies from our laboratory and others raise a number of questions concerning the rat's appropriateness as an animal model for toxicol...

257

THE BENEFITS OF A QUALITY ASSURANCE REVIEW OF A RESEARCH STUDY ON THE PHYSICOCHEMISTRY AND PULMONARY TOXICOLOGICAL PROPERTIES OF ORIMULSION FLY ASH  

EPA Science Inventory

THE BENEFITS OF A QUALITY ASSURANCE REVIEW OF A RESEARCH STUDY ON THE PHYSICOCHEMISTRY AND PULMONARY TOXICOLOGICAL PROPERTIES OF ORIMULSION FLY ASH. K Dreher', J. Richards', J. McGee', J. Lehmann', T. Hughes', A. Miller, W. Linak2, and A. Mallett3.'National Health and Environment...

258

A preparation of murine liver fragments for in vitro studies: liver preparation for toxicological studies  

PubMed Central

Background The aim of this study was to develop liver tissue preparation suitable for investigating toxins. Hepatocyte respiration, ATP content, urea synthesis, caspase activity and morphology were measured as a function of in vitro incubation time. Mice were anesthetized by sevoflurane inhalation. Small liver fragments were then rapidly excised and incubated at 37°C in Krebs-Henseleit buffer (continuously gassed with 95% O2: 5% CO2) for up to 6 h. Phosphorescence O2 analyzer was used to determine the rate of cellular mitochondrial O2 consumption (kc, ?M O2 min-1 mg-1). Cellular ATP was measured using the luciferin/luciferase system. The caspase-3 substrate N-acetyl-asp-glu-val-asp-7-amino-4-methylcoumarin (Ac-DEVD-AMC) was used to monitor intracellular caspase activity; cleaved AMC moieties (reflecting caspase activity) were separated on HPLC and detected by fluorescence. Findings Respiration was inhibited by cyanide, confirming the oxidation occurred in the respiratory chain. The values of kc (mean ± SD) for 0? t ?6 h were 0.15 ± 0.02 ?M O2 min-1 mg-1 (n = 18, coefficient of variation, CV = 13%), ATP content 131 ± 69 pmol mg-1 (1? t ?6 h, n = 16, CV = 53%), synthesized urea 0.134 ± 0.017 mg/dL mg-1 in 50 min (0? t ?6 h, n = 14, CV = 13%), and AMC peak area 62,540 ± 26,227 arbitrary units mg-1 (1? t ?6 h, n = 3, CV = 42%). Hepatocyte morphology and organelles were reasonably persevered. Conclusions The described liver tissue preparation demonstrates stable hepatocyte structure, ultrastructure and biomarkers for up to 6 h, permitting in vitro studies.

2013-01-01

259

Preclinical investigations with mistletoe (Viscum album L.) extract Iscador.  

PubMed

The mistletoe (Viscum album L.) extract Iscador has been shown to be an effective complementary drug in the treatment of cancer patients after surgical removal of the primary tumor. It improved survival, recovery from damage caused by irradiation or cytostatic therapy, and quality of life. Beneficial effects were seen especially as reduction of the side effects caused by basic oncological therapy. In animal tests, clear anti-carcinogenic effects of Iscador were demonstrated as reduction of tumor growth in preformed tumors and as prevention of tumor growth in newly induced tumors. Mainly immune stimulation but also direct cytotoxic activity are believed to be responsible for the anti-carcinogenic activity of Iscador. Other effects seen in patients, such as improved quality of life and improved psychic conditions, are not possible to be tested in animals. Recently, toxicological investigations were performed with Iscador to get more information on possible toxicological effects which can only be evaluated in preclinical studies. Tests examining the acute toxicity, genotoxic effects as well as effects on reproduction were performed. In these studies, no adverse effects of Iscador preparations were detected thus confirming the information on the safety of the extract which has been gained in clinical trials and during more than 80 years of use in human therapy. Iscador has been shown to be essentially safe. No severe adverse events have been reported during many years of use by thousands of patients. Genotoxic effects and effects on reproduction, which cannot be evaluated in clinical use, have been cleared up in animal tests. Iscador was shown to be clearly non-genotoxic and free of relevant toxic effects on reproduction in vivo. In summary, no risk of adverse effects of Iscador during human use is expected. PMID:16927531

Maldacker, Juliane

2006-06-01

260

Inhalation developmental toxicology studies: Teratology study of n-hexane in rats: Final report  

SciTech Connect

The straight chain hydrocarbon, n-hexane, is a volatile, ubiquitous solvent used in industrial, academic, and smaller commercial environments. The significant opportunity for women of child-bearing age to be exposed to this chemical prompted the undertaking of a study to assess the developmental toxicity of n-hexane in an animal model. Timed-pregnant (30 animals per group) and virgin (10 animals per group) Sprague-Dawley rats were exposed to 0 (filtered air), 200, 1000, and 5000 ppM n-hexane (99.9% purity) vapor in inhalation chambers for 20 h/day for a period of 14 consecutive days. Sperm-positive females were exposed for 6 to 19 days of gestation (dg) and virgins were exposed concurrently for 14 consecutive days. The day of sperm detection was designated as 0 dg for mated females. Adult female body weights were monitored prior to, throughout the exposure period, and at sacrifice. Uterine, placental, and fetal body weights were obtained for gravid females at sacrifice. Implants were enumerated and their status recorded as live fetus, early or late resorption, or dead. Live fetuses were sexed and examined for gross, visceral, skeletal, and soft-tissue craniofacial defects. 16 refs., 3 figs., 7 tabs.

Mast, T.J.

1987-12-01

261

Flexible use of QSAR models in predictive toxicology: a case study on aromatic amines.  

PubMed

Over the last years, predictive toxicology approaches based on Structure-Activity Relationships have emerged as fundamental tools in the regulatory assessments of chemicals, especially in those programs where regulatory constraints and assessment schemes limit the amount of data available from experimental test methods. Both the qualitative (e.g., Structural Alerts) and the quantitative (Quantitative Structure-Activity Relationships, QSAR) approach can play important roles. However, the two approaches are not familiar to the same extent to the regulators that most often use only the qualitative approach, so that the potentiality of the more sophisticated QSAR approach is neglected. In fact, QSAR is a very flexible tool that allows the user to modulate its response according to different goals and requirements. Here, we present a non-naïve approach to the use of a QSAR relative to a dichotomous biological activity (such as mutagen/nonmutagen), and we show how the user can maximize alternatively the reliability of the prediction of negative compounds (i.e., safe chemicals) or that of positive chemicals (i.e., chemicals that pose high hazard). Because of the environmental and industrial importance of the class of aromatic amines, we apply the approach to a previously published QSAR on the Salmonella typhimurium mutagenicity of these chemicals. PMID:22329023

Benigni, Romualdo; Bossa, Cecilia

2012-01-01

262

History of wildlife toxicology.  

PubMed

The field of wildlife toxicology can be traced to the late nineteenth and early twentieth centuries. Initial reports included unintentional poisoning of birds from ingestion of spent lead shot and predator control agents, alkali poisoning of waterbirds, and die-offs from maritime oil spills. With the advent of synthetic pesticides in the 1930s and 1940s, effects of DDT and other pesticides were investigated in free-ranging and captive wildlife. In response to research findings in the US and UK, and the publication of Silent Spring in 1962, public debate on the hazards of pollutants arose and national contaminant monitoring programs were initiated. Shortly thereafter, population-level effects of DDT on raptorial and fish-eating birds were documented, and effects on other species (e.g., bats) were suspected. Realization of the global nature of organochlorine pesticide contamination, and the discovery of PCBs in environmental samples, launched long-range studies in birds and mammals. With the birth of ecotoxicology in 1969 and the establishment of the Society of Environmental Toxicology and Chemistry in 1979, an international infrastructure began to emerge. In the 1980s, heavy metal pollution related to mining and smelting, agrichemical practices and non-target effects, selenium toxicosis, and disasters such as Chernobyl and the Exxon Valdez dominated the field. Biomarker development, endocrine disruption, population modeling, and studies with amphibians and reptiles were major issues of the 1990s. With the turn of the century, there was interest in new and emerging compounds (pharmaceuticals, flame retardants, surfactants), and potential population-level effects of some compounds. Based upon its history, wildlife toxicology is driven by chemical use and misuse, ecological disasters, and pollution-related events affecting humans. Current challenges include the need to more thoroughly estimate and predict exposure and effects of chemical-related anthropogenic activities on wildlife and their supporting habitat. PMID:19533341

Rattner, Barnett A

2009-06-17

263

Quality in environmental toxicology measurements.  

PubMed

From the clinical chemist's point of view, environmental toxicology can be defined as the identification or quantitation or both of environmental toxicants, their metabolites, and the biochemical consequences in easily accessible human specimens. Requirements as to specificity, accuracy, precision, and sensitivity will vary depending on the purpose of the analysis (e.g., diagnosis of acute intoxication vs. population baseline study). Laboratories must therefore clearly indicate the scope of their analytic methods. To ensure consistency of results, quality guidelines, such as International Standards Organization (ISO) guide 25, should be adhered to. However, to demonstrate accuracy, external proficiency assessment is required. Interlaboratory comparison programs, by using representative reference material, can document laboratory performance over time. Examples taken from the Quebec Toxicology Centre's program for toxic metals in biologic fluids indicate that laboratory performance has improved in recent years. The quality of results is generally adequate for most applications of environmental toxicology measurements. PMID:8857572

Weber, J P

1996-08-01

264

Case studies for practical food effect assessments across BCS/BDDCS class compounds using in silico, in vitro, and preclinical in vivo data.  

PubMed

Practical food effect predictions and assessments were described using in silico, in vitro, and/or in vivo preclinical data to anticipate food effects and Biopharmaceutics Classification System (BCS)/Biopharmaceutics Drug Disposition Classification System (BDDCS) class across drug development stages depending on available data: (1) limited in silico and in vitro data in early discovery; (2) preclinical in vivo pharmacokinetic, absorption, and metabolism data at candidate selection; and (3) physiologically based absorption modeling using biorelevant solubility and precipitation data to quantitatively predict human food effects, oral absorption, and pharmacokinetic profiles for early clinical studies. Early food effect predictions used calculated or measured physicochemical properties to establish a preliminary BCS/BDDCS class. A rat-based preclinical BCS/BDDCS classification used rat in vivo fraction absorbed and metabolism data. Biorelevant solubility and precipitation kinetic data were generated via animal pharmacokinetic studies using advanced compartmental absorption and transit (ACAT) models or in vitro methods. Predicted human plasma concentration-time profiles and the magnitude of the food effects were compared with observed clinical data for assessment of simulation accuracy. Simulations and analyses successfully identified potential food effects across BCS/BDDCS classes 1-4 compounds with an average fold error less than 1.6 in most cases. ACAT physiological absorption models accurately predicted positive food effects in human for poorly soluble bases after oral dosage forms. Integration of solubility, precipitation time, and metabolism data allowed confident identification of a compound's BCS/BDDCS class, its likely food effects, along with prediction of human exposure profiles under fast and fed conditions. PMID:23139017

Heimbach, Tycho; Xia, Binfeng; Lin, Tsu-han; He, Handan

2012-11-10

265

[Actual problems of genetic toxicology].  

PubMed

The review deals with current issues of genetic toxicology and aims to develop this science at the contemporary stage. We study general approaches to assessing the genotoxic and mutagenic activity of environmental factors; to constructing a regulatory system of chemical compounds that considers the mutagenic effect in Russia and abroad; and to determining modem methods for assessing the organ specificity of mutagens, alternative methods of genetic toxicology, the mutagenic action of various factors in the survey of population, and the abilities of toxicogenomics to identify the mutagenic properties of the environment. PMID:23755529

Sycheva, L P; Zhurkov, V S; Rakhmanin, Iu A

2013-03-01

266

Human pharmaceuticals in the aquatic environment: a review of recent toxicological studies and considerations for toxicity testing.  

PubMed

Although an increasingly large amount of data exists on the acute and chronic aquatic toxicity of pharmaceuticals, numerous questions still remain. There remains a dearth of information pertaining to the chronic toxicity of bivalves, benthic invertebrates, fish, and endangered species, as well as study designs that examine mechanism-of-action (MOA)-based toxicity, in vitro and computational toxicity, and pharmaceutical mixtures. Studies examining acute toxicity are prolific in the published literature; therefore, we address many of the shortcomings in the literature by proposing "intelligent" well-designed aquatic toxicology studies that consider comparative pharmacokinetics and pharmacodynamics. For example, few studies on the chronic responses of aquatic species to residues of pharmaceuticals have been performed, and very few on variables that are plausibly linked to any therapeutic MOA. Unfortunately, even less is understood about the metabolism of pharmaceuticals in aquatic organisms. Therefore, it is clear that toxicity testing at each tier of an ecological risk assessment scheme would be strengthened for some pharmaceuticals by selecting model organisms and endpoints to address ecologically problematic MOAs. We specifically recommend that future studies employ AOP approaches (Ankley et al. 2010) that leverage mammalian pharmacology information, including data on side effects and contraindications. Use of conceptual AOP models for pharmaceuticals can enhance future studies in ways that assist in the development of more definitive ecological risk assessments, identify chemical classes of concern, and help protect ecosystems that are affected by WWTP effluent discharge. PMID:22488604

Brausch, John M; Connors, Kristin A; Brooks, Bryan W; Rand, Gary M

2012-01-01

267

TOXICOLOGICAL SAFETY OF IRRADIATED FOODS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Irradiation of food and agricultural products is allowed in over 60 countries around the world, and has only been allowed only after extensive testing for toxicological safety. Studies conducted over a 50 year period found no detectable increases in the risk of cancer or birth defects associated wi...

268

NATIONAL TOXICOLOGY PROGRAM (NTP) DATA  

EPA Science Inventory

The National Toxicology Program (NTP) was established in 1978 by the Department of Health and Human Services (DHHS) to coordinate toxicological testing programs within the department, strengthen the science base in toxicology; develop and validate improved testing methods; and pr...

269

Timing of Decompressive Surgery of Spinal Cord after Traumatic Spinal Cord Injury: An Evidence-Based Examination of Pre-Clinical and Clinical Studies  

PubMed Central

Abstract While the recommendations for spine surgery in specific cases of acute traumatic spinal cord injury (SCI) are well recognized, there is considerable uncertainty regarding the role of the timing of surgical decompression of the spinal cord in the management of patients with SCI. Given this, we sought to critically review the literature regarding the pre-clinical and clinical evidence on the potential impact of timing of surgical decompression of the spinal cord on outcomes after traumatic SCI. The primary literature search was performed using MEDLINE, CINAHL, EMBASE, and Cochrane databases. A secondary search strategy incorporated articles referenced in prior meta-analyses and systematic and nonsystematic review articles. Two reviewers independently assessed every study with regard to eligibility, level of evidence, and study quality. Of 198 abstracts of pre-clinical studies, 19 experimental studies using animal SCI models fulfilled our inclusion and exclusion criteria. Despite some discrepancies in the results of those pre-clinical studies, there is evidence for a biological rationale to support early decompression of the spinal cord. Of 153 abstracts of clinical studies, 22 fulfilled the inclusion and exclusion criteria. While the vast majority of the clinical studies were level-4 evidence, there were two studies of level-2b evidence. The quality assessment scores varied from 7 to 25 with a mean value of 12.41. While 2 of 22 clinical studies assessed feasibility and safety, 20 clinical studies examined efficacy of early surgical intervention to stabilize and align the spine and to decompress the spinal cord; the most common definitions of early operation used 24 and 72?h after SCI as timelines. A number of studies indicated that patients who undergo early surgical decompression can have similar outcomes to patients who received a delayed decompressive operation. However, there is evidence to suggest that early surgical intervention is safe and feasible and that it can improve clinical and neurological outcomes and reduce health care costs. Based on the current clinical evidence using a Delphi process, an expert panel recommended that early surgical intervention should be considered in all patients from 8 to 24?h following acute traumatic SCI.

Furlan, Julio C.; Noonan, Vanessa; Cadotte, David W.

2011-01-01

270

Generating nano-aerosols from TiO? (5 nm) nanoparticles showing different agglomeration states. Application to toxicological studies.  

PubMed

Agglomeration of nanoparticles (NP) is a key factor in the generation of aerosols from nano-powders and may represent an important parameter to consider in toxicological studies. For this reason, the characterization of NP aerosols (e.g., concentration, size, and structure of agglomerates) is a critical step in the determination of the relationship between exposure and effects. The aim of this study was to generate and characterize aerosols composed of TiO? (5 nm) NP showing different agglomeration states. Two concentrations were tested: 2 and 7 mg/m³. Stable mass concentrations over 6 hr were successfully generated by a wet method using Collison and Delavan nebulizers that resulted in aerosols composed of smaller agglomerates (<100 nm), while aerosols composed of larger agglomerates (>100 nm) were obtained by dry generation techniques using either a Palas dust feeder or a Fluidized Bed. Particle size distributions in the aerosols were determined by an electrical low pressure impactor. Median number aerodynamic diameters corresponding to the aerosol with smaller and larger agglomerates were 30 and 185 nm, respectively, for the 2 mg/m³ concentration, and 31 and 194 nm for the 7 mg/m³ experiment. Image analysis by transmission electron microscopy showed the presence of compact or agglomerates with void spaces in the different nano-aerosols. These characterized nano-aerosols will be used in further experiments to study the influence of agglomerate size on NP toxicity. PMID:23252512

Noël, Alexandra; Cloutier, Yves; Wilkinson, Kevin James; Dion, Chantal; Hallé, Stéphane; Maghni, Karim; Tardif, Robert; Truchon, Ginette

2013-01-01

271

101. Toxicology and Biodistribution Studies of a Recombinant Adeno-Associated Virus 2 (rAAV2) Alpha1 Antitrypsin (AAT) Vector  

Microsoft Academic Search

A series of safety and biodistribution studies were undertaken to support the development of a muscle-based gene therapy system for AAT deficiency. AAT is the primary circulating serum proteinase inhibitor, and its deficiency can result in emphysema. The test article that was used in this toxicology study was rAAV serotype 2 with the CMV\\/Beta Actin promoter driving expression of the

Amy E. Poirier; Lynn A. Combee; Ashley T. Martino; Terence R. Flotte

2004-01-01

272

Toxicology of brotizolam  

PubMed Central

1 Acute studies. Following oral or intraperitoneal administration, toxicity was very low (LD50 in rodents > 10,000 and > 900 mg/kg, respectively). 2 Subacute and chronic studies in rodents. Signs of toxicity were seen only at doses of 400 mg/kg or more. Histopathological changes were found only in the 78-week study. 3 Subacute studies in dogs (intravenous) and primates (oral). In dogs, doses of 0.1 and 0.3 mg/kg produced ataxia, salivation, and diarrhoea. In monkeys doses of 7 mg/kg or higher produced ataxia, increased appetite, hyperreflexive muscular spasms, increase in liver weight, and lipid depletion of the adrenal cortex. 4 Reproductive studies in the rat and rabbit. Repeated doses of up to 30 mg/kg were not associated with any disturbance in fertility; nor were any embryotoxic or teratogenic effects observed. When dams were treated with 400 mg/kg, litter mortality was markedly increased. 5 Mutagenicity studies. The four different tests performed gave no indication of any mutagenic effect. 6 Local tolerance tests in the rabbit. Brotizolam was well tolerated when administered intramuscularly, intra-arterially, or intravenously. 7 Carcinogenicity studies in rodents. The mouse study showed no evidence of a tumourigenic effect. The rat study is still being evaluated. 8 The toxicological studies demonstrate that brotizolam has an unusually wide therapeutic range. Findings of toxicological significance, most of which were reversible, were first recorded at doses of 7-10 mg/kg, i.e. at more than 100-times the intended human therapeutic dose.

Hewett, C.; Kreuzer, H.; Kollmer, H.; Niggeschulze, A.; Stotzer, H.

1983-01-01

273

Intersex in Japanese medaka (Oryzias latipes) used as negative controls in toxicologic bioassays: a review of 54 cases from 41 studies.  

PubMed

Histologic assessment of the gonads to detect intersex has become a valuable end point in reproductive toxicologic testing for fish, and many studies have solidly linked intersex with exposure to endocrine active substances (EAS). An assumption in such studies is that spontaneous intersex does not occur in control fish. Using historical data derived from toxicologic tests with Japanese medaka (Oryzias latipes), we report a retrospective study in which we identified 54 individual instances of intersex (testicular oocytes or ovarian testicular tissue) in control medaka from 15 of 41 selected toxicologic studies. These studies, comprised of previously unpublished data, had been conducted at three geographically distant laboratories, each of which utilized unique water sources, employed somewhat different culture protocols, and maintained distinct medaka breeding colonies. During our histologic examinations, we also identified three germ cell neoplasms that had been inadvertently diagnosed as intersex. In the present report, we review potential causes of intersex, discuss possible reasons why spontaneous intersex has rarely been reported, and propose suggestions for the judicious interpretation of intersex results in medaka studies involving EAS. PMID:17702336

Grim, K Christiana; Wolfe, Marilyn; Hawkins, William; Johnson, Rodney; Wolf, Jeffrey

2007-08-01

274

Pulmonary Edema Due to Oral Gavage in a Toxicological Study Related to Aquaporin-1, -4 and -5 Expression  

PubMed Central

A one-time oral gavage can be enough to cause of alveologenic edema with higher expression of AQP-1 and -4 than that with repeated-dose oral gavage, which caused both profound perivascular edema and hydrostatic pressure edema, while AQP-5 was similarly expressed. The alteration of AQPs expression was probably related to alveolar fluid clearance across the alveolar and bronchiolar epithelium in different stages of lung injury. The results clarified the type of lung edema in acute and sub-chronic toxicity studies without treatment related effect of tested material. The pathogenesis of pulmonary edema due to oral gavage toxicological study is associated with the cellular immune response to the reflux materials. Mast cell and leukocyte accumulation may contribute to increase vascular permeability leading to permeability edema. The increase in alveolar septum epithelium, perivascular and peribronchial cuffing, accumulation alveolar lipid containing macrophage and medial hyperplasia of the pulmonary artery might have been caused to increase airway resistance, which resulted in hydrostatic pressure edema.

Singha, Ornuma; Kengkoom, Kanchana; Chaimongkolnukul, Khuanjit; Cherdyu, Sompong; Pongponratn, Emsri; Ketjareon, Taweesak; Panavechkijkul, Yaowaluk; Ampawong, Sumate

2013-01-01

275

Processing nanoparticles with A4F-SAXS for toxicological studies: Iron oxide in cell-based assays.  

PubMed

Nanoparticles are not typically ready-to-use for in vitro cell culture assays. Prior to their use in assays, powder samples containing nanoparticles must be dispersed, de-agglomerated, fractionated by size, and characterized with respect to size and size distribution. For this purpose we report exemplarily on polyphosphate-stabilized iron oxide nanoparticles in aqueous suspension. Fractionation and online particle size analysis was performed in a time-saving procedure lasting 50 min by combining asymmetrical flow field-flow fractionation (A4F) and small-angle X-ray scattering (SAXS). Narrowly distributed nanoparticle fractions with radii of gyration (R(g)) from 7 to 21 nm were obtained from polydisperse samples. The A4F-SAXS combination is introduced for the preparation of well-characterized sample fractions originating from a highly polydisperse system as typically found in engineered nanoparticles. A4F-SAXS processed particles are ready-to-use for toxicological studies. The results of preliminary tests of the effects of fractionated iron oxide nanoparticles with a R(g) of 15 nm on a human colon model cell line are reported. PMID:21129749

Knappe, Patrick; Boehmert, Linda; Bienert, Ralf; Kamutzki, Silvana; Karmutzki, Silvana; Niemann, Birgit; Lampen, Alfonso; Thünemann, Andreas F

2010-11-16

276

Toxicology ontology perspectives.  

PubMed

The field of predictive toxicology requires the development of open, public, computable, standardized toxicology vocabularies and ontologies to support the applications required by in silico, in vitro, and in vivo toxicology methods and related analysis and reporting activities. In this article we review ontology developments based on a set of perspectives showing how ontologies are being used in predictive toxicology initiatives and applications. Perspectives on resources and initiatives reviewed include OpenTox, eTOX, Pistoia Alliance, ToxWiz, Virtual Liver, EU-ADR, BEL, ToxML, and Bioclipse. We also review existing ontology developments in neighboring fields that can contribute to establishing an ontological framework for predictive toxicology. A significant set of resources is already available to provide a foundation for an ontological framework for 21st century mechanistic-based toxicology research. Ontologies such as ToxWiz provide a basis for application to toxicology investigations, whereas other ontologies under development in the biological, chemical, and biomedical communities could be incorporated in an extended future framework. OpenTox has provided a semantic web framework for the implementation of such ontologies into software applications and linked data resources. Bioclipse developers have shown the benefit of interoperability obtained through ontology by being able to link their workbench application with remote OpenTox web services. Although these developments are promising, an increased international coordination of efforts is greatly needed to develop a more unified, standardized, and open toxicology ontology framework. PMID:22562487

Hardy, Barry; Apic, Gordana; Carthew, Philip; Clark, Dominic; Cook, David; Dix, Ian; Escher, Sylvia; Hastings, Janna; Heard, David J; Jeliazkova, Nina; Judson, Philip; Matis-Mitchell, Sherri; Mitic, Dragana; Myatt, Glenn; Shah, Imran; Spjuth, Ola; Tcheremenskaia, Olga; Toldo, Luca; Watson, David; White, Andrew; Yang, Chihae

2012-01-01

277

Validating animal models for preclinical research: a scientific and ethical discussion.  

PubMed

The use of animals to model humans in biomedical research relies on the notion that basic processes are sufficiently similar across species to allow extrapolation. Animal model validity is discussed in terms of the similarity between the model and the human condition it is intended to model, but no formal validation of models is applied. There is a stark contrast here with the use of non-animal alternatives in toxicology and safety studies, for which an extensive validation is required. We discuss both the potential and the limitations of validating preclinical animal models for proof-of-concept studies, by using an approach similar to that applied to alternative non-animal methods in toxicology and safety testing. A major challenge in devising a validation system for animal models is the lack of a clear gold standard with which to compare results. While a complete adoption of the validation approach for alternative methods is probably inappropriate for research animal models, key features, such as making data available for external validation and defining a strategy to run experiments in a way that permits meaningful retrospective analysis, remain highly relevant. PMID:20602541

Varga, Orsolya E; Hansen, Axel K; Sandøe, Peter; Olsson, I Anna S

2010-06-01

278

Antagonism of haloperidol-induced swim impairment in L-dopa and caffeine treated mice: a pre-clinical model to study Parkinson's disease.  

PubMed

Parkinson's disease (PD) exhibits symptoms of motor dysfunction such as tremor, akinesia and rigidity. Agents that selectively disrupt or destroy catecholaminergic systems, such as reserpine, methamphetamine, 6-hydroxydopamine and 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine, have been used to develop PD models and to study the animal behavior like catalepsy, akinesia, swim-test, etc. The major apprehension while working with these chemicals is their irreversible neuro-toxic effect. Haloperidol is a classical antipsychotic drug, which produces extra-pyrimidal Parkinson's symptoms (EPS). Measuring catalepsy and akinesia in the treated mice monitored the haloperidol-induced EPS. Alternatively, swimming disability was tested as a new parameter to monitor haloperidol-induced EPS. The results showed that the restoration of swimming disability in haloperidol-induced L-dopa and caffeine pre-treated mice could be used as pre-clinical model to study PD. PMID:19146880

Luthra, Pratibha Mehta; Barodia, Sandeep Kumar; Raghubir, Ram

2008-12-25

279

Pharmacology Toxicology Review recd July 5, 2012 ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... of administration and be based on experimental data that ... may be present in human plasma ... However, these toxicology studies were conducted with ... More results from www.fda.gov/downloads/biologicsbloodvaccines/bloodbloodproducts

280

MINING ENVIRONMENTAL TOXICOLOGY INFORMATION WEB RESOURCES  

EPA Science Inventory

Environmental toxicology is the study of the ecological effects of anthropogenic substances released into the environment. It is a relatively diverse field addressing impacts to aquatic and terrestrial organisms and communities. The determination of potential risk associated with...

281

CD40 ligand is necessary and sufficient to support primary diffuse large B-cell lymphoma cells in culture: a tool for in vitro preclinical studies with primary B-cell malignancies  

PubMed Central

Established cell lines are utilized extensively to study tumor biology and preclinical therapeutic development; however, they may not accurately recapitulate the heterogeneity of their corresponding primary disease. B-cell tumor cells are especially difficult to maintain under conventional culture conditions, limiting access to samples that faithfully represent this disease for preclinical studies. Here, we used primary canine diffuse large B-cell lymphoma to establish a culture system that reliably supports the growth of these cells. CD40 ligand, either expressed by feeder cells or provided as a soluble two-trimeric form, was sufficient to support primary lymphoma cells in vitro. The tumor cells retained their original phenotype, clonality and known karyotypic abnormalities after extended expansion in culture. Finally, we illustrate the utility of the feeder cell-free culture system for comparable assessment of cytotoxicity using dog and human B-cell malignancies. We conclude this system has broad applications for in vitro preclinical development for B-cell malignancies.

Ito, Daisuke; Frantz, Aric M.; Williams, Christina; Thomas, Rachael; Burnett, Robert C.; Avery, Anne C.; Breen, Matthew; Mason, Nicola J.; O'Brien, Timothy D.; Modiano, Jaime F.

2013-01-01

282

[Studies of biologic activation associated with molecular receptor increase and tumor response in ChL6/L6 protocol patients; Studies in phantoms; Quantitative SPECT; Preclinical studies; and Clinical studies]. DOE annual report, 1994--95  

SciTech Connect

The authors describe results which have not yet been published from their associated studies listed in the title. For the first, they discuss Lym-1 single chain genetically engineered molecules, analysis of molecular genetic coded messages to enhance tumor response, and human dosimetry and therapeutic human use radiopharmaceuticals. Studies in phantoms includes a discussion of planar image quantitation, counts coincidence correction, organ studies, tumor studies, and {sup 90}Y quantitation with Bremsstrahlung imaging. The study on SPECT discusses attenuation correction and scatter correction. Preclinical studies investigated uptake of {sup 90}Y-BrE-3 in mice using autoradiography. Clinical studies discuss image quantitation verses counts from biopsy samples, S factors for radiation dose calculation, {sup 67}Cu imaging studies for lymphoma cancer, and {sup 111}In MoAb imaging studies for breast cancer to predict {sup 90}Y MoAb therapy.

DeNardo, S.J.

1995-12-31

283

Toxicology and Carcinogenesis Studies of Quercetin (CAS No. 117-39-5) in F344 Rats (Feed Studies).  

PubMed

Quercetin is a member of a group of naturally occurring compounds, the flavonoids, which have a common flavone nucleus composed of two benzene rings linked through a heterocyclicpyrone ring. Quercetin is found in various plants, food products, and dyes of natural origin. The estimated average daily intake of quercetin by an individual in the United States is 25 mg. The Food and Drug Administration nominated quercetin for toxicity and carcinogenicity studies in the rat because it is a chemical that is widely distributed in foods. Quercetin was administered to rats by dosed feed since human exposure is by dietary consumption. Information in the literature showed that quercetin administered in the diet to rats at levels up to approximately 4% caused a minor body weight effect, whereas higher dose levels produced greater than 10% reduction in body weight gains relative to controls. Based on this information, the NTP 2-year studies were conducted by administering 0, 1,000, 10,000, or 40,000 ppm quercetin (>95% pure) in feed to groups of 50 male and female rats for 104 weeks. Ten additional animals per dose group were evaluated at 6 and 15 months. Body Weight, Survival, and Clinical Findings in the 2-Year Studies: Body weights of exposed male and female rats given 1,000 and 10,000 ppm were within 5% of controls throughout the studies. Reduced body weight gain in male and female rats receiving 40,000 ppm was observed by week 15 and the final mean body weights were 87% of controls at week 104. Survival and feed consumption were similar among exposed and control groups throughout the studies. The average amounts of quercetin consumed per day by the 1,000, 10,000 and 40,000 ppm dose groups after week 52 were 40, 400, and 1,900 mg/kg of body weight. Nonneoplastic and Neoplastic Effects in the 2-Year Studies: In male rats, the principal toxic effects associated with the dietary administration of quercetin for 2 years were observed in the kidney. There were dose-related increases in the severity of chronic nephropathy (control, 2.7; low-dose, 2.7; mid-dose, 3.0; high-dose, 3.2) and a slight increased incidence in focal hyperplasia of the renal tubule epithelium (1/50; 2/50; 3/50; 4/50). Parathyroid hyperplasia, indicative of renal secondary hyperparathyroidism, also increased incidence in dosed male rats (1/43, 6/45, 6/43, 17/43). The evaluation of single sections from the left and right kidneys revealed renal tubule adenomas in three male rats and adenocarcinomas in another male rat receiving 40,000 ppm quercetin; none were seen in the controls. Examination of additional step sections of the male rat kidney identified additional hyperplasia and adenomas in all dose groups (hyperplasia: 2/50, 2/50, 6/50, 8/50; adenoma: 1/50, 2/50, 7/50, 6/50). The overall incidence of renal tubule adenoma or adenocarcinoma combined in male rats was 1/50 in controls and 9/50 in the high-dose group. There was no apparent effect of quercetin on the kidney of female rats. A single renal tubule adenoma was seen in a female receiving 10,000 ppm; this neoplasm was not considered biologically significant. There was a statistically significant, dose-related decrease in the incidence of mammary gland fibroadenomas in exposed female rats (29/50, 27/50, 16/50, 9/50), which may in part be attributed to lower body weight gains. There was a treatment-related accumulation of yellow-brown granular pigment adsorbed to or absorbed by the epithelial cells of the glandular stomach, ileum, jejunum, and, to a lesser extent, the duodenum and colon. The severity of the pigmentation in these tissues increased with increased length of exposure. There were no other lesions considered to be related to chemical administration. Genetic Toxicology: Quercetin induced gene mutations in Salmonella typhimurium strains TA100 and TA98 with and without exogenous metabolic activation (S9). Positive results were also obtained in tests with and without S9 for induction of sister chromatid exchanges and chromosomal aberrations in Chinese hamster ovary cells. Conclusions: Under the conditio

1992-09-01

284

Preclinical Studies to Predict Efficacy of Vascular Changes Induced by Combretastatin A-4 Disodium Phosphate in Patients  

SciTech Connect

Purpose: To determine how combretastatin A-4 disodium phosphate (CA4DP) dose-dependent changes in radiation response of a C3H mouse mammary carcinoma relate to measurements of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters and how those mouse DCE-MRI results compare with published clinical DCE-MRI data. Methods and Materials: C3H mammary carcinomas grown in female CDF{sub 1} mice were treated when at 200 mm{sup 3} in size. Groups of mice were given graded radiation doses, either alone or followed 30 min later by an intraperitoneal injection of CA4DP, administered at doses of 10-250 mg/kg. The radiation dose producing local tumor control in 50% of treated animals at 90 days (TCD{sub 50}) was calculated for each CA4DP dose. DCE-MRI was performed before and 3 h after CA4DP administration, and parameters describing vascularity and interstitial volume were estimated. Results: TCD{sub 50} showed a dose-dependent decrease reaching significance at 25 mg/kg. At greater doses of 50 and 100 mg/kg, the TCD{sub 50} increased slightly and was not significantly different from that of controls. TCD{sub 50} significantly decreased again at 250 mg/kg. The drug dose-response curves for all post-treatment vascular DCE-MRI parameters showed a shape similar to that of the TCD{sub 50} curve. A similar dose dependency was seen with previously published clinical data. Conclusion: Our preclinical DCE-MRI data could predict the CA4DP enhancement of the tumor radiation response and suggest the clinical CA4DP doses necessary to improve the radiation response in patients.

Nielsen, Thomas [Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus (Denmark); Department of Neuroradiology, Aarhus University Hospital, Aarhus (Denmark)], E-mail: thomas@oncology.dk; Murata, Rumi [Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus (Denmark); Maxwell, Ross J. [University of Newcastle Upon Tyne, Northern Institute for Cancer Research, Newcastle Upon Tyne (United Kingdom); Stodkilde-Jorgensen, Hans [MR Research Centre, Aarhus University Hospital, Aarhus (Denmark); Ostergaard, Leif [Department of Neuroradiology, Aarhus University Hospital, Aarhus (Denmark); Horsman, Michael R. [Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus (Denmark)

2008-03-01

285

The chemical, toxicological and ecological studies in assessing the heavy metal pollution in Le An River, China  

Microsoft Academic Search

By integrating the chemical, toxicological and ecological data, the impact of heavy metal pollution on the Le An River was assessed. The results showed that the water and sediment pollution has affected the aquatic ecosystem due to discharges from Dexing copper mines and mines along the Jishui River. The ecological deterioration between the Dexing copper mine and the converges with

Mengchang He; Zijian Wang; Hongxiao Tang

1998-01-01

286

Biosensors for Aquatic Toxicology Evaluation  

Microsoft Academic Search

There is an increasing need for effective tools to estimate the risks derived from the large number of pollutants released\\u000a to the environment by human activities. These studies need the combination of chemical analysis and ecotoxicological evaluation.\\u000a Environmental toxicology is the qualitative and quantitative study of the adverse effects of anthropogenic and naturally occurring\\u000a chemical stressors.\\u000a \\u000a Initial aquatic ecotoxicology studies

Marinella Farré; Damià Barceló

287

Gram-scale purification of flavonolignan diastereoisomers from Silybum marianum (Milk Thistle) extract in support of preclinical in vivo studies for prostate cancer chemoprevention.  

PubMed

Extracts of milk thistle ( Silybum marianum, Asteraceae), termed "silymarin," are used worldwide, primarily for hepatoprotective applications and recently for prostate cancer chemoprevention. Silymarin is a mixture of at least eight compounds, and four major constituents are a group of structurally related flavonolignans: silybin A, silybin B, isosilybin A, and isosilybin B. The initiation of IN VIVO studies to compare the respective preclinical activities of each compound required that gram quantities of these diastereoisomers be prepared. Procedures were developed and optimized to produce multigram-scale quantities of each of these in > 97 % purity. A hybrid chromatographic/precipitative technique was developed, whereby mixtures were chromatographed at high concentrations so as to induce formation of a precipitate in the column fractions, yielding samples that were more enriched in the desired compounds than would be obtained solely by the chromatographic steps alone. PMID:17948171

Graf, Tyler N; Wani, Mansukh C; Agarwal, Rajesh; Kroll, David J; Oberlies, Nicholas H

2007-10-18

288

Generation of genetically-modified human differentiated cells for toxicological tests and the study of neurodegenerative diseases.  

PubMed

Human differentiated cell types, such as neurons or hepatocytes, are of limited availability, and their use for experiments requiring ectopic gene expression is challenging. We explored here in the human conditionally-immortalized neuronal precursor line LUHMES, whether genetic modification in the proliferating state could be used for experiments in the differentiated post-mitotic neurons. First, alpha-synuclein (ASYN), a gene associated with the pathology of Parkinson's disease, was overexpressed. Increased amounts of the protein were tolerated without change of phenotype, and this approach allows now further studies on protein variants. Knockdown of ASYN augmented the toxicity of the parkinsonian toxicant 1-methyl-4-phenylpyridinium (MPP+). Different lentiviral constructs were then tested: cells labeled ubiquitously by green (GFP) or red fluorescent protein (RFP) allowed the quantification of neurite growth, and of its disturbance by toxicants; expression of proteins of interest could be targeted to different organelles; production of two different proteins from a single read-through construct was achieved successfully by an expression strategy using a linker peptide between the two proteins, which is cleaved by deubiquitinases; LUHMES, labeled with GFP in the cytosol and RFP in the mitochondria were used to quantify mitochondrial mobility along the neurites. MPP+ reduced such organelle movement before any other detectable cellular change, and this toxicity was prevented by simultaneous treatment with the antioxidant ascorbic acid. Thus, a strategy has been outlined here, to study new functional endpoints and subtle changes of structure and proteostasis, relevant in toxicology and biomedicine in post-mitotic human cells. PMID:23743630

Schildknecht, Stefan; Karreman, Christiaan; Pöltl, Dominik; Efremova, Liudmila; Kullmann, Cornelius; Gutbier, Simon; Krug, Anne; Scholz, Diana; Gerding, Hanne; Leist, Marcel; Schildknecht, Stefan

2013-06-01

289

Preclinical Operative Dentistry Courses in Northern Europe and Scandinavia.  

ERIC Educational Resources Information Center

|This study compares teaching methods, time spent, and materials used in the existing preclinical teaching efforts of dental schools in 11 Northern European states (Belgium, Denmark, Eire, Finland, France, Germany, Netherlands, Norway, Sweden, Switzerland, and United Kingdom). Results reveal considerable variation in the teaching of preclinical

Wilson, N. H. F.; And Others

1993-01-01

290

Preclinical Imaging of Mammary Intraepithelial Neoplasia with Positron Emission Tomography  

Microsoft Academic Search

Small-animal imaging with positron emission tomography (PET) has become a valuable tool for evaluating preclinical models of breast cancer and other diseases. In this review, we examine a number of issues related to preclinical imaging studies with PET, using transgenic models of ductal carcinoma in situ and metastasis as specific examples. We discuss imaging components such as reconstruction, normalization, and

Craig K. Abbey; Alexander D. Borowsky; Jeffery P. Gregg; Robert D. Cardiff; Simon R. Cherry

2006-01-01

291

[Toxicological studies on pepleomycin sulfate (NK 631). I. Acute toxicity of pepleomycin in mice, rats and dogs (author's transl)].  

PubMed

Studies on acute toxicities of pepleomycin sulfate were carried out in both sexes of mice and rats, comparing with bleomycin, and male dogs. Pepleomycin was administered subcutaneously, intravenously and intraperitoneally in both sexes of mice and rats, and intravenously in male dogs respectively. Mice and rats, and intravenously in male dogs respectively. Mice and rats were observed respectively for 10 and 14 days after the administration. LD50 values were calculated by the method of Litchifield & Wilcoxon. LD50 values of pepleomycin were 4 approximately 6 times smaller than those of bleomycin in all routes of mice, but difference between them was not significant in all routes of rats. Additionally sex-difference of LD50 values was scacely recognized in all routes of both species. Toxicological findings observed in common to all routes of both species were ataxia, depression, tremor and epiphora, and only in all routes of mice, head-twitch, running-round and rolling were especially recognized as toxic behavior, which were not observed in bleomycin. Hepatic and renal lesions were recognized in biochemically and histopathologically in the survived rats. The dogs treated with pepleomycin 50 and 30 mg/kg had the decrease in food intake and the loss of body weight. They became moribund in 9 approximately 36 days after administration. In these dogs the lesions of liver and kidney were severely recognized in biochemical and histopathological findings. One of them which received 50 mg/kg recovered biochemically and histopathologically in 209 days after administration by the supplemental nutrition in early stage. PMID:83404

Ito, K; Irie, Y; Miyamoto, K; Yamashita, T; Tsubosaki, M; Matsuda, A; Konoha, N

1978-12-01

292

Intuitive Toxicology: The Public Perception of Nanoscience  

Microsoft Academic Search

\\u000a “Intuitive toxicology” is much more than a clever term. It refers to how an inexpert or lay audience comprehends and reacts\\u000a differently to expert information, in this case quantitative toxicology data. There is a tyranny of risk assessment and management\\u000a in policy making. Experts solicit and collect data on hazards based on in vitro and in vivo studies. They pair

David M. Berube

293

Toxicologic Effects of Air Pollution on Reproduction. Epidemiological Studies - Literature Review.  

National Technical Information Service (NTIS)

Air pollutions include a number of toxic agents emitted from fossil fuels (NOsub (x), SO sub 2 , CO, POM heavy metals). Epidemiological studies of health effects from such pollutions have been performed concerning lung cancer and cancer mortality, disease...

S. Nordstroem B. Forsberg

1983-01-01

294

Toxicology Study of Diisopropyl Methylphosphonate and Dicyclopentadiene in Mallard Ducks, Bobwhite Quail and Mink.  

National Technical Information Service (NTIS)

This study was conducted to determine the toxicity, and tissue residue accumulation, of diisopropyl methylphosphonate (DIMP) and dicyclopentadiene (DCPD) in wildlife. The toxicity was evaluated by acute (LD50), subacute (LC50) and chronic tests with Malla...

D. Polin K. S. Howell R. J. Aulerich R. K. Ringer T. H. Coleman

1979-01-01

295

Preclinical and clinical research on inflammation after intracerebral hemorrhage  

PubMed Central

Intracerebral hemorrhage (ICH) is one of the most lethal stroke subtypes. Despite the high morbidity and mortality associated with ICH, its pathophysiology has not been investigated as well as that of ischemic stroke. Available evidence from preclinical and clinical studies suggests that inflammatory mechanisms are involved in the progression of ICH-induced secondary brain injury. For example, in preclinical ICH models, microglial activation has been shown to occur within 1 h, much earlier than neutrophil infiltration. Recent advances in our understanding of neuroinflammatory pathways have revealed several new molecular targets, and related therapeutic strategies have been tested in preclinical ICH models. This review summarizes recent progress made in preclinical models of ICH, surveys preclinical and clinical studies of inflammatory cells (leukocytes, macrophages, microglia, and astrocytes) and inflammatory mediators (matrix metalloproteinases, nuclear factor erythroid 2-related factor 2, heme oxygenase, and iron), and highlights the emerging areas of therapeutic promise.

Wang, Jian

2010-01-01

296

DISEASE REGISTRY TOXICOLOGICAL PROFILES  

EPA Science Inventory

By Congressional mandate, the Agency for Toxic Substances and Disease Registry (ATSDR) produces "toxicological profiles" for hazardous substances found at National Priorities List (NPL) sites. These hazardous substances are ranked based on frequency of occurrence at NPL sites, to...

297

Computational Toxicology (S)  

EPA Science Inventory

The emerging field of computational toxicology applies mathematical and computer models and molecular biological and chemical approaches to explore both qualitative and quantitative relationships between sources of environmental pollutant exposure and adverse health outcomes. Th...

298

The Toxicology of Beryllium.  

National Technical Information Service (NTIS)

Review of the physiology, toxicology, pathology, analytical determination, and experimental testing of beryllium and beryllium compounds. Tabulated data are given for the effect, body distribution, excretion and blood levels of various beryllium compounds...

I. R. Tabershaw

1972-01-01

299

Genetic Toxicology: An Overview.  

ERIC Educational Resources Information Center

|Provides background information about the current state of a new field of science, genetic toxicology. Discusses mutations and cancer, the history of the field, and detection of genetic damage. (CS)|

Naismith, Robert W.

1980-01-01

300

Genistein effects on haematoimmune cells in a newly developed alternative toxicological model  

Microsoft Academic Search

Unexpected, sometimes opposite effects of dietary isoflavonic phytoestrogens on immunity may suggest that classical mammalian toxicological assays are not entirely suitable for preclinical safety tests of these compounds. We evaluated a new alternative model of haemocytes of Egyptian cotton worm in vivo following genistein administration. Genistein induced significant changes in nucleolar morphology of haemocytes but did not influence their counts

Veronika Picmonova; Josef Berger

301

Toxicological significance of dihydrodiol metabolites  

SciTech Connect

Dihydrodiols are often found as the major organic-extractable metabolites of various olefinic or aromatic xenobiotics in many biological samples. Studies on the chemistry of dihydrodiol metabolites have provided insight into the pharmacokinetic behavior and the mode of action of the parent compound. The toxicology of dihydrodiol is more complex than what can be deduced solely on the basis of diminished bioavailability of the epoxide precursor, and the increased hydrophilicity associated with the dihydrodiol moiety. Dihydrodiols can be intrinsically toxic and may even represent metabolically activated species. Some of the dihydrodiol metabolites may still retain sufficient lipophilic character to serve again as substrates for microsomal oxygenases. Because of the tremendous chemical and biological diversity that existed among the various dihydrodiols, more mechanistic studies are needed to examine the toxicological properties of these compounds. It may be premature to conclude dihydrodiol formation as purely a detoxification route for xenobioties.

Hsia, M.T.

1982-01-01

302

Preliminary toxicology study of 3,6-diamino-1,2,4,5-tetrazine  

SciTech Connect

The calculated acute oral LD 30/50 (lethal dose for 50% of the animals occurring within 30 days after compound administration) value for 3,6-diamino-1,2,4,5-tetrazine (DATZ) was 863 mg/kg in rats. According to classical guidelines, DATZ would be considered slightly to moderately toxic for rats. The calculated acute oral LD {sub 30/50} value was 2,288 mg/kg in mice and would be considered slightly to moderately toxic for mice. Skin application studies using rabbits demonstrated DATZ to be a nonirritant. The eye study using rabbits disclosed DATZ to be a very mild irritant. The sensitization study using guinea pigs did not show DATZ to have potential sensitizing properties.

London, J.E.

1993-03-01

303

Toxicology and carcinogenesis studies of benzofuran (CAS No. 271-89-6) in F344/N rats and B6C3f1 mice (gavage studies). Technical report series  

SciTech Connect

Benzofuran is used as an intermediate in the polymerization of coumarone-indene resins found in various corrosion-resistant coatings such as paints and varnishes, in water-resistant coatings for paper products and fabrics, and in adhesives approved for use in food containers. Toxicology and carcinogenesis studies were conducted by administering benzofuran (approximately 99% pure) in corn oil by gavage to groups of F344/N rats and B6C3F1 mice of each sex for 14 days, 13 weeks, or 2 years. Genetic toxicology tests were conducted in Salmonella typhimurium, mouse lymphoma cells, and Chinese hamster ovary (CHO) cells.

Irwin, R.

1989-10-01

304

alpha 2u-globulin nephropathy and renal tumors in national toxicology program studies.  

PubMed

Chemically induced renal neoplasms in male rats, developed coincident with alpha(2u)-globulin nephropathy, are not considered predictive of risk to humans by the International Agency for Research on Cancer (IARC) and the U.S. Environmental Protection Agency. Criteria have been defined to establish the role of alpha(2u)-globulin nephropathy in renal carcinogenesis, based on a proposed mode of action involving sustained tubular cell proliferation resulting from alpha(2u)-induced nephropathy, with consequent development of neoplastic lesions. Recent NTP studies demonstrated inconsistencies with this proposed mechanism, including in some cases, far weaker kidney tumor responses than expected based on the extent of alpha(2u)-globulin nephropathy. NTP studies with decalin, propylene glycol mono-t-butyl ether and Stoddard solvent IIC included extended evaluations of alpha(2u)-related nephropathy, and were thus used in assessing the linkage between key events in 90-day studies with renal tumors in 2-year studies. This review revealed no or at best weak associations of tumor responses with renal alpha(2u)-globulin concentrations, indices of cell turnover, or microscopic evidence of alpha(2u)-associated nephropathy in prechronic studies. While tumor responses corresponded somewhat with a measure of cumulative alpha(2u)-associated nephropathy (linear mineralization of the papilla) at the end of the 2-year studies, the severity of chronic nephropathy was generally in best agreement with the pattern of tumor response. These results suggest that while alpha(2u)-globulin nephropathy may contribute to the renal tumor response, the critical component(s) of the nephropathy most closely associated with the development of tumors could not be clearly identified in this review. PMID:17562486

Doi, Adriana M; Hill, Georgette; Seely, John; Hailey, James R; Kissling, Grace; Bucher, John R

2007-06-01

305

Toxicology Studies with Cytembena (NSC-104,801) in Beagle Dogs and Rhesus Monkeys.  

National Technical Information Service (NTIS)

Cytembena NSC-104,801, was studied for toxic effects following intravenous administration to Beagle dogs and Rhesus monkeys at dose levels ranging from 12.5-200 mg/kg/day in dogs and 6.25-50 mg/kg/day in monkeys, given as either single doses, daily for fi...

E. J. Gralla G. L. Coleman

1973-01-01

306

APPLICATION OF CDNA MICROARRAY TO THE STUDY OF ARSENIC TOXICOLOGY AND CARCINOGENESIS  

EPA Science Inventory

Arsenic (As) is a common environmental toxicant and known human carcinogen. Epidemiological studies link As exposure to various disorders and cancers. However, the molecular mechanisms for As toxicity and carcinogenicity are not completely known. The cDNA microarray, a high-th...

307

Toxicological Studies on Beryllium and Oxides and Beryllium-Containing Exhaust Products.  

National Technical Information Service (NTIS)

Results of long-term studies on rats and rabbits, injected intratracheally with well-characterized key samples of beryllium oxide prepared by calcining beryllium hydroxide for 10 hours at 500, 1100 and 1600 C, respectively, show clearly that there is a de...

H. C. Spencer J. A. Blumenshine R. H. Hook S. B. McCollister S. E. Sadek

1968-01-01

308

Particulate matter properties and health effects: consistency of epidemiological and toxicological studies  

Microsoft Academic Search

Identifying the ambient particulate matter (PM) fractions or constituents, critically involved in eliciting adverse health effects, is crucial to the implementation of more cost-efficient abatement strategies to improve air quality. This review focuses on the importance of different particle properties for PM-induced effects, and whether there is consistency in the results from epidemiological and experimental studies. An evident problem for

P E Schwarze; J Øvrevik; M Låg; M Refsnes; P Nafstad; R B Hetland; E Dybing

2006-01-01

309

Toxicology and Carcinogenesis Studies of 3-Chloro-2-Methylpropene (Technical Grade Containing 5% Dimethylvinyl Chloride) (CAS No. 563-47-3) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies of technical-grade 3-chloro-2-methylpropene (containing 5% dimethylvinyl chloride), a widely used insecticide and chemical intermediate, were performed on F344/N rats and B6C3F1 mice. In the 13-week studies, 50%-100% ...

1986-01-01

310

Status of study on biological and toxicological effects of nanoscale materials  

Microsoft Academic Search

Because the physical and chemical properties of nanosized materials mostly differ from the existing microsized materials,\\u000a their potential impacts on human health and the environment will be topics under the serious discussions in press and in a\\u000a number of international scientific journals. We analyze and summarize the existing data of the experimental study on the biological\\u000a activities and adverse effects

Bing Wang; Weiyue Feng; Yuliang Zhao; Gengmei Xing; Zhifang Chai; Haifang Wang; Guang Jia

2005-01-01

311

Modification of Rochester chambers for toxicological studies of concentrated oil aerosols  

Microsoft Academic Search

An exposure system for the study of diesel oil aerosols is described. An evaporation-condensation generator capable of producing sub-micron sized aerosols of diesel oil in the concentration range of 0.5 to 20. g\\/m³ was designed and interfaced to Rochester style exposure chambers. It was found that the existing chamber design was not adequate to provide a uniformly distributed aerosol. This

R. W. Holmbers; J. H. Moneyhun; W. Dalbey

1980-01-01

312

Shellfish: Toxicology studies. (Latest citations from the NTIS Bibliographic database). Published Search  

SciTech Connect

The bibliography contains citations concerning the effects of toxic substances on shellfish. Petroleum products, solvents, sewage, copper, mercury, chromium, dredged materials, and organic chemicals are among the toxic substances studied. Reproductive impairment, molting behavior, and population reduction caused by toxic chemicals are discussed. Shellfish as bioindicators and shellfish tolerance to toxic substances are briefly considered. (Contains 250 citations and includes a subject term index and title list.)

Not Available

1993-12-01

313

Acute and chronic toxicological studies of Dimorphandra mollis in experimental animals.  

PubMed

Dimorphandra mollis Benth. (Caesalpiniaceae), known as "faveira" or "fava d'anta" is a common plant in central Brazilian cerrado that is used mainly as a vasoprotector. Its main marker is rutin. The present study aimed to evaluate the security of Dimorphandra mollis dry extract in rodents. The extract presented a rutin content of 76+/-3%. Acute and chronic (180 days) toxicity was evaluated after per os administration. In acute toxicity, 3500 and 5000 mg/kg doses presented reversible effects. In chronic toxicity, 1000 and 2000 mg/kg doses did not provoke significant changes in body weight of the animals and in water and food consumption. Behavioral reversible changes and in blood count parameters (hemoglobin, hematocrit and red cells decrease and platelets increase in male in rats) were observed only in 2000 mg/kg dose. In biochemical evaluation, the results varied a lot considering doses and sex, without a linear profile. Some parameters showed a significant difference but without a clinical correlation. In histopathological examination, lung hemorrhage was observed in 2000 mg/kg dose. In conclusion, the study suggest that the extract is safe in a 1000 mg/kg dose, whereas for 2000 mg/kg dose further studies are needed. In long-term use, caution is required. PMID:16872769

Féres, C A O; Madalosso, R C; Rocha, O A; Leite, J P V; Guimarães, T M D P; Toledo, V P P; Tagliati, C A

2006-06-23

314

Toxicological evaluation of a dietary supplement formulated for male sexual health prior to market release.  

PubMed

The dietary supplement, 112 Degrees, was formulated with the goal of supporting sexual functioning in men. Due to rampant problems with drug adulteration for this category of products, a comprehensive screening for active pharmaceutical agents, with an emphasis on drugs prescribed for erectile dysfunction such as type 5 phosphodiesterase (PDE-5) inhibitors, and known unapproved PDE-5 drug analogues, was performed along with preclinical toxicology studies prior to the introduction of this product into the marketplace. 112 Degrees was found to be free of all pharmaceutical adulterants tested, and was not mutagenic, clastogenic, or genotoxic as demonstrated by the Ames test, chromosomal aberration assay, and mouse micronucleus assay, respectively. The LD(50) in the 14-day acute oral toxicity study was greater than 5000 mg/kg, the highest dose tested. PMID:20043970

Clewell, A; Qureshi, I; Endres, J; Horváth, J; Financsek, I; Neal-Kababick, J; Jade, K; Schauss, A G

2010-01-04

315

Toxicology and carcinogenesis studies of microencapsulated citral in rats and mice.  

PubMed

Citral, a widely used natural ingredient, is added to foods and cosmetics as a flavoring and fragrance agent. Male and female F344/N rats and B6C3F1 mice were exposed to microencapsulated citral in the feed for 14 weeks or two years. All studies included untreated and vehicle control groups. In the 14-week studies, rats and mice were given diets containing 3,900, 7,800, 15,600, or 31,300 ppm citral. In rats, food consumption was reduced in the two highest dose groups. In mice an apparent increase in food consumption was observed, but was due to mice scattering the feed. Body weights of all treated animals were less than controls. All rats and four male mice were killed moribund in the high dose groups. In rats, forestomach and kidney lesions were observed. At the higher doses, lesions observed in the bone marrow, testes, and thymus in rats and in the ovary in mice were considered related to inanition and resultant moribundity. In the two-year studies, rats were exposed to 1,000, 2,000, or 4,000 ppm citral. Body weights were reduced in the 4,000 ppm rats. Mice were exposed to 500, 1,000, or 2,000 ppm citral. Body weights in the 1,000 and 2,000 ppm groups were reduced. No neoplasms were attributed to citral in rats or mice. Malignant lymphoma occurred with a positive trend and was significantly greater than controls in female mice in the 2,000 ppm group. However, the incidences were within the NTP historical control range and could not be clearly related to citral administration. PMID:12563105

Ress, N B; Hailey, J R; Maronpot, R R; Bucher, J R; Travlos, G S; Haseman, J K; Orzech, D P; Johnson, J D; Hejtmancik, M R

2003-02-01

316

Toxicology and carcinogenesis studies of microencapsulated trans-cinnamaldehyde in rats and mice.  

PubMed

trans-Cinnamaldehyde is a widely used natural ingredient that is added to foods and cosmetics as a flavoring and fragrance agent. Male and female F344/N rats and B6C3F(1) mice were exposed to microencapsulated trans-cinnamaldehyde in the feed for three months or two years. All studies included untreated and vehicle control groups. In the three-month studies, rats and mice were given diets containing 4100, 8200, 16,500, or 33,000 ppm trans-cinnamaldehyde. In rats, feed consumption was reduced in all exposed groups. In mice, feed consumption was reduced in the highest dose groups. Body weights of all treated males were less than controls. Body weights were reduced in female rats exposed to 16,500 or 33,000 ppm and female mice exposed to 8200 ppm or greater. All rats survived to the end of the study but some male mice in the highest dose groups died due to inanition from unpalatability of the dosed feed. The incidence of squamous epithelial hyperplasia of the forestomach was significantly increased in rats exposed to 8200 ppm or greater and female mice exposed to 33,000 ppm. In mice, the incidence of olfactory epithelial degeneration of the nasal cavity was significantly increased in males and females exposed to 16,500 ppm and females exposed to 33,000 ppm. In the two-year studies, rats and mice were exposed to 1000, 2100, or 4100 ppm trans-cinnamaldehyde. Body weights were reduced in mice exposed to 2100 ppm and in rats and mice exposed to 4100 ppm. In rats, hippuric acid excretion was dose proportional indicating that absorption, metabolism, and excretion were not saturated. No neoplasms were attributed to trans-cinnamaldehyde in rats or mice. Squamous cell papillomas and carcinomas of the forestomach were observed in male and female mice but the incidences were within the NTP historical control range and were not considered to be related to trans-cinnamaldehyde exposure. PMID:15350673

Hooth, M J; Sills, R C; Burka, L T; Haseman, J K; Witt, K L; Orzech, D P; Fuciarelli, A F; Graves, S W; Johnson, J D; Bucher, J R

2004-11-01

317

Heart rate variability in rodents: uses and caveats in toxicological studies.  

PubMed

Heart rate variability (HRV) is a measure of cardiac pacing dynamics that has recently garnered a great deal of interest in environmental health studies. While the use of these measures has become popular, much uncertainty remains in the interpretation of results, both in terms of human and animal research. In humans, HRV endpoints, specifically chronic alterations in baseline HRV patterns, have been reasonably well characterized as prognostic indicators of adverse outcomes for a variety of diseases. However, such information is lacking for reversible HRV changes that may be induced by short-term exposures to environmental toxicants. Furthermore, there are minimal substantive data, either acute or chronic, regarding the pathological interpretation or prognostic value of toxicant-induced changes in HRV in rodents. The present report summarizes the physiological and clinical aspects of HRV, the methodological processes for obtaining these endpoints, and previous human and animal studies in the field of environmental health. Furthermore, we include a discussion of important caveats and recommendations for the interpretation of HRV data in animal research. PMID:17646680

Rowan, William H; Campen, Matthew J; Wichers, Lindsay B; Watkinson, William P

2007-01-01

318

Relationship between fetal weight and litter size in rats: application to reproductive toxicology studies.  

PubMed

The inverse relationship between mammalian fetal weight and litter size has been discussed by many authors, but their opinions reveal no agreement at all. As in toxicity studies of reproduction, both parameters must be correctly evaluated. We investigated the existence of such a relationship in 2466 fetuses from 203 litters of Sprague-Dawley CD control rats. The frequency distribution of fetal weights had a normal adjustment. From the mean weight of fetuses in each litter, the mean fetal weights in each litter size and correlation coefficient were calculated and the regression line was plotted; the correlation coefficient (r = 0.677) was highly significant (P = 0.002), which made evident that there was an inverse relationship between fetal weight and litter size. If fetal weight/litter size inverse relationship is not taken into account when toxicity on the fetal weight is analyzed, wrong conclusions may be reached if the test substance reduces the litter size, provoking embryofoetal mortality. The iatrogenic decrement in fetal weight can be masked by an increment due to the litter size reduction. We suggest that in all three segments of reproductive toxicity studies, litter size must be considered as a covariate to the effect of the test substance on the fetal weight, in order to perform a correct analysis of covariance (ANCOVA), in addition to the dose factor commonly used in common ANOVA. PMID:1463926

Romero, A; Villamayor, F; Grau, M T; Sacristán, A; Ortiz, J A

1992-01-01

319

[Toxicological studies on pepleomycin sulfate (NK631). III. Subacute toxicity of pepleomycin in dogs (author's transl)].  

PubMed

Subacute toxicity and its recovery of pepleomycin sulfate was studied in both sexes of beagle dogs. At dose levels of 2.4, 1.2 and 0.6 mg/kg, pepleomycin was administered intramuscularly to dogs for 30 successive days. Two dogs of the 1.2 mg/kg dose group were used for recovery test for 35 days. As general symptoms, the decrease of food intake, the loss of body weight, ulceration of foot pad, nail root necrosis and onychoptosic, ulcer of tongue and labia, and alopecia, dermatitis and necrosis at friction sites were observed the more severely in high dose groups, as those in bleomycin were. The death occurred in the 2.4 mg/kg dose group of both sexes. The lesions of liver and kidney were recognized in the 2.4 and 1.2 mg/kg dose groups of both sexes on biochemical, histopathological or urinary findings. Additionally slight fibrous change of lung was observed in all dose groups. Generally subacute toxicity of pepleomycin was revealed approximately in the same as or in a little stronger degree than that of bleomycin, and its recovery was hardly recognized during its period. The maximum safety dose in this studies is estimated to be between 0.3 and 0.6 mg/kg in dogs. PMID:83406

Ito, K; Handa, J; Irie, Y; Ezura, H; Kumagai, M; Irie, Y; Suzuki, A; Miyamoto, K; Yamashita, T; Tsubosaki, M; Matsuda, A; Konoha, N

1978-12-01

320

Immunohistochemical investigation of F344/N rat islet cell tumors from national toxicology program studies.  

PubMed

In this study, we have investigated the immunoexpression of peptide hormones and mediators associated with human islet cell tumors in a group of proliferative islet cell lesions in F344 rats including islet cell hyperplasias, adenomas, and carcinomas, as defined by conventional histopathologic criteria. All proliferative islets expressed synaptophysin, although decreased expression intensity was observed in hyperplasias and adenomas. Most of the proliferative lesions expressed insulin, which generally decreased as lesions progressed toward malignancy. The distribution of glucagon, somatostatin, and gastrin-expressing cells was altered in proliferative islet lesions but did not comprise a large proportion of cells. Islet cell tumors were associated with increased nuclear expression of cyclin-dependent kinase 4 as well as increased proliferating cell nuclear antigen and decreased ?-catenin expression. c-Myelocytomatosis oncogene expression was variable. This is the first study to describe the immunophenotype of islet cell tumors in the F344 rat and to show that islet cell tumors in the F344 rat exhibit similarities in protein expression to the human counterpart. PMID:22477723

Koivisto, Christopher; Flake, Gordon P; Kolenda-Roberts, Holly; Masinde, Tiwanda; Kissling, Grace E; Sills, Robert C; Hoenerhoff, Mark J

2012-04-03

321

HILIC-UPLC-MS for exploratory urinary metabolic profiling in toxicological studies.  

PubMed

Hydrophilic interaction ultra performance liquid chromatography (HILIC-UPLC) permits the analysis of highly polar metabolites, providing complementary information to reversed-phase (RP) chromatography. HILIC-UPLC-TOF-MS was investigated for the global metabolic profiling of rat urine samples generated in an experimental hepatotoxicity study of galactosamine (galN) and the concomitant investigation of the protective effect of glycine. Within-run repeatability and stability over a large sample batch (>200 samples, 60 h run-time) was assessed through the repeat analysis of a quality control sample. Following system equilibration, excellent repeatability was observed in terms of retention time (CV < 1.7%), signal intensity (CV < 14%), and mass variability (<0.005 amu), providing a good measure of reproducibility. Classification of urinary metabolic profiles according to treatment was observed, with significant changes in specific metabolites after galN exposure, including increased urocanic acid, N-acetylglucosamine, and decreased 2-oxoglutarate. A novel finding from this HILIC-UPLC-MS approach was elevated urinary tyramine in galN-treated rats, reflecting disturbed amino acid metabolism. These results show HILIC-UPLC-MS to be a promising method for global metabolic profiling, demonstrating high within-run repeatability, even over an extended run time. Retention of polar endogenous analytes and xenobiotic metabolites was improved compared with RP studies, including galN, N-acetylglucosamine, oxoglutarate, and urocanic acid, enhancing metabolome coverage and potentially improving biomarker discovery. PMID:21142126

Spagou, Konstantina; Wilson, Ian D; Masson, Perrine; Theodoridis, Georgios; Raikos, Nikolaos; Coen, Muireann; Holmes, Elaine; Lindon, John C; Plumb, Robert S; Nicholson, Jeremy K; Want, Elizabeth J

2010-12-13

322

Pre-clinical Models for Oral and Periodontal Reconstructive Therapies  

PubMed Central

The development of new medical formulations (NMF) for reconstructive therapies has considerably improved the available treatment options for individuals requiring periodontal repair or oral implant rehabilitation. Progress in tissue engineering and regenerative medicine modalities strongly depends on validated pre-clinical research. Pre-clinical testing has contributed to the recent approval of NMF such as GEM 21S® and INFUSE® bone grafts for periodontal and oral regenerative therapies. However, the selection of a suitable pre-clinical model for evaluation of the safety and efficacy of a NMF remains a challenge. This review is designed to serve as a primer to choose the appropriate pre-clinical models for the evaluation of NMF in situations requiring periodontal or oral reconstruction. Here, we summarize commonly used pre-clinical models and provide examples of screening and functional studies of NMF that can be translated into clinical use.

Pellegrini, G.; Seol, Y.J.; Gruber, R.; Giannobile, W.V.

2009-01-01

323

Personality and performance of preclinical medical students.  

PubMed

This study deals with personality variables of medical students in relation to their academic success in the preclinical stage. One hundred and one students completed the 16PF Questionnaire at the beginning of their medical course and the scores were analysed in relation to their marks obtained at the end of the 2-year preclinical stage. This study shows that the 16PF Questionnaire can be a useful instrument for identifying personality variables in candidates who are likely to have academic problems and those who are likely to do well in the preclinical stage of a medical course. Students of urban origin and the eldest in the family performed better in their preclinical years. Performance was not related to sex, ethnic group, family size of entrance qualification into medicine. Personality variables of being enthusiastic, venturesome, self-opinionated, imaginative, experimenting, resourceful and driven correlate positively with performance, whereas being self-assured has negative correlation. Problem students were more reserved, emotionally less stable and more apprehensive than non-problem students. PMID:8594392

Peng, R; Khaw, H H; Edariah, A B

1995-07-01

324

Antinociceptive effect and toxicological study of the aqueous bark extract of Barringtonia racemosa on rats.  

PubMed

Barringtonia racemosa Linn. (Family Lecythidaceae) possess several bioactivities and is used in traditional medicine of Sri Lanka, but its analgesic potential has not been investigated so far. The aim of this study was therefore to examine the antinociceptive potential of an aqueous bark extract (500, 750, 1000 or 1500 mg/kg) of B. racemosa in male rats using three models of nociception (tail flick, hot plate and formalin tests). The results showed that the extract has antinociceptive activity (when evaluated in hot plate and formalin test but not in tail flick test) without producing unwanted side effects or toxicity. Further, the extract did not alter fertility, gestational length, peri- and neonatal development and appears to be non-teratogenic. The antinociceptive effect was mediated mainly via opioid mechanisms. Such inhibition of pain could arise from phenolic and steroidal constituents as was shown to be present in the extract. PMID:12686437

Deraniyagala, S A; Ratnasooriya, W D; Goonasekara, C L

2003-05-01

325

Optical oxygen microrespirometry as a platform for environmental toxicology and animal model studies.  

PubMed

We present a new methodology for testing physiological responses of small organisms (size 70-500 microm) via changes in their oxygen respiration monitored by quenched-phosphorescence oxygen sensing on a scale of a single organism. The method is demonstrated using three different formats of respirometric assays, Artemia salina and mouse embryos as model animals, and various effectors including compounds that induce and prevent superoxide-mediated and heavy metal ion toxicity. These assays, which employ soluble oxygen probes, standard fluorescent readers, and accessorytools, provide sensitive, noninvasive, real-time monitoring of animal respiration, and rapid assessment of EC50, sublethal effects, and metabolic alterations. Applications include screening for acute toxicity of compound libraries and environmental samples, and the study of animal physiology and metabolism. PMID:16053104

O'Mahony, Fiach C; O'Donovan, Ciara; Hynes, James; Moore, Tom; Davenport, John; Papkovsky, Dmitri B

2005-07-01

326

Toxicological studies of organophosphate and pyrethroid insecticides for controlling the fruit fly Dacus ciliatus (Diptera: Tephritidae).  

PubMed

The fruit fly Dacus ciliatus Loew is a pest of the fruits of many cucurbit species. We studied the effect of organaophosphate and pyrethroid compounds on the adult flies by using surface contact and oral administration. In contrast to other fruit flies, we found that organophosphates were ineffective against D. ciliatus. This was supported by the insignificant decrease of head acetylcholinesterase activity. All tested pyrethroids showed satisfactory killing ability, rapid and massive knockdown effect, and prevention of oviposition. Piperonyl butoxide considerably increased the toxicity of pyrethroids, which can be explained by oxidase detoxification of these compounds in D. ciliatus. It can be concluded that pyrethroids have high potential for controlling D. ciliatus. PMID:11681666

Maklakov, A; Ishaaya, I; Freidberg, A; Yawetz, A; Horowitz, A R; Yarom, I

2001-10-01

327

[Cyanide poisoning: forensic toxicology observations in the study of 54 cases of fatal poisoning].  

PubMed

The present study describes various observations made during the examination of 54 cases of lethal cyanide intoxication at the Institute of Forensic Medicine of the University of Zürich during a period of more than 40 years. Data pertain to the scene of death, the medicolegal inspection, the autopsy, the histological examinations, the chemical analyses, the various types of poisoning observed and the diagnostic criteria used. The intoxicated victims were mostly adults who had professional access to various cyanogenic compounds and had ingested them with the intention of committing suicide. Cases of accidental and criminal poisoning were rare. In spite of this fact, and although its frequency has not increased in the last few decades, cyanide poisoning has maintained undiminished importance. PMID:4060897

Pasi, A; Morath, M; Hartmann, H

1985-01-01

328

Analytical and toxicological studies of decomposition of insecticide parathion after gamma-irradiation and ozonation.  

PubMed

The decomposition of the widely used organophosphorus pesticide parathion was carried out in aqueous solutions by the use of gamma-irradiation from a 60Co source or ozonation by means of an ozone generator, and by combined processes of ozonation and radiolysis. Factors affecting the parathion decomposition as well formation and decomposition of the main by-products, including irradiation dose, length of ozonation time, and presence of common scavengers, were investigated. The most efficient was found to be the gamma-irradiation process combined with a short ozonation period; about 1 kGy irradiation dose was sufficient to decompose the pesticide in 15 mg/L solutions. Chemical studies of the decomposition of parathion were accompanied by monitoring of toxicity changes of irradiated solutions with the Microtox test. PMID:23175969

Bojanowska-Czajka, Anna; Torun, Murat; Kciuk, Gabriel; Wachowicz, Mariusz; Ozbay, Dilek Solpan; Guven, Olgun; Bobrowski, Krzysztof; Trojanowicz, Marek

329

Novel biological recycling water purification system for use in fish toxicology studies  

SciTech Connect

A major problem with fish toxicity testing has been maintaining an adequate supply of healthy, acclimated fish in the laboratory setting from which test populations can be obtained. The build-up of metabolic waste (ammonia) in holding tank environments leads to a stressful situation for the fish, resulting in mortality or erroneous toxicity data. Ammonia is the principal nitrogenous waste product of catfish and is excreted primarily as the toxic unionized ammonia from the gills. The purpose of this study was to develop a novel biological filter system which facilitates the nitrification process, thereby removing or controlling the build-up of toxic metabolic waste products in holding tanks in the laboratory. This system would provide a healthy, non-stressful environment for blue channel catfish (Ictalurus Punctatus) fingerlings prior to their use in LC50 determinations of various insecticides, herbicides, and fungicides currently employed in the vicinity of catfish ponds or farms.

Veriangieri, A.J.; Lewis, R.M.; Bannon, A.W.; Wilson, M.C.

1988-02-01

330

Tissue-specific toxicological effects of cadmium in green mussels (Perna viridis): nuclear magnetic resonance-based metabolomics study.  

PubMed

Toxicity tests for metals have traditionally focused on selected biomarkers to characterize the biological stress induced by metals in marine organisms. Here nuclear magnetic resonance (NMR)-based metabolomics, a system biology tool, was applied to the marine green mussel, Perna viridis, to investigate the toxicological effects of Cd in both digestive gland and adductor muscle tissues. After Cd exposure for either two or four weeks, there was no significant metabolic change in the mussels exposed to Cd at 2?µg/L. At 20?µg/L, there were major metabolite changes related to amino acids, osmolytes, and energy metabolites. Digestive gland tissue was more sensitive to Cd than adductor muscle tissue. The adductor muscle tissue showed elevated levels of glutamine, glutamate, and lactate, and reduced levels of branched chain amino acids, aspartate, phenylalanine, and tyrosine. Overall, four weeks of Cd exposure produced neurotoxicity and metabolic disturbances and disturbed osmoregulation. These results suggest that the adductor muscle tissue of mussels may be a suitable supplemental biomarker for exposure to toxicants. In addition, the results demonstrate that (1) H-NMR-based metabolomic analysis can provide a systematic view of the toxicological effects of metals on mussels, suggesting that it might be employed to investigate the toxicological effects of other marine pollutants. PMID:21184531

Wu, Huifeng; Wang, Wen-Xiong

2011-02-21

331

The hepatotoxicity of valproic acid and its metabolites in rats. I. Toxicologic, biochemical and histopathologic studies.  

PubMed

Valproic acid (VPA), its unsaturated metabolites and pent-4-enoate (4-PA) were studied for potential hepatotoxicity in rats. 4-PA, 4-en-VPA and 2,4-dien-VPA were potent inducers of microvesicular steatosis in young rats. Microvesicular steatosis induced by the 4-en-VPA was accompanied by ultrastructural changes characterized by myeloid bodies, lipid vacuoles and mitochondrial abnormalities. Myeloid bodies and lipid vacuoles were seen to a lesser extent in 2,4-dien-VPA and 4-PA-treated rats. VPA failed to induce discernible liver lesions in young rats even at near lethal doses of 700 mg per kg per day. The drug did, however, induce hepatic lipid accumulation in mature rats and in young rats dosed concomitantly with phenobarbital. beta-oxidation inhibition and several other biochemical alterations were observed in rats dosed with VPA, its unsaturated metabolites and 4-PA. It was suggested that beta-oxidation inhibition observed in both VPA and en-metabolite-treated rats occurred by different mechanisms. VPA inhibits by a transient sequestering of CoA while the CoA esters of some en-VPA-metabolites, particularly 4-en-VPA, inhibit specific enzyme(s) in the beta-oxidation sequences. PMID:6437960

Kesterson, J W; Granneman, G R; Machinist, J M

332

Toxicometallomics for research on the toxicology of exotic metalloids based on speciation studies.  

PubMed

Tellurium and antimony are widely used in industry because of their unique chemical and physical properties. Although these metalloids, which belong to period 5 of the periodic table of elements, are known to be non-essential and harmful, or the so-called "exotic" elements, little is known about their toxic effects and metabolism. The present review describes the role of speciation in considering the metabolism of tellurium and antimony from the viewpoint of toxicometallomics. Inorganic tellurium in the form of tellurite is reduced and simply methylated in the body. Rat red blood cells accumulate tellurium in the form of dimethylated tellurium, and tellurium is excreted into urine as trimethyltelluronium. Although selenium, which belongs to the same group as tellurium, is known to be excreted in the form of selenosugar as the major urinary metabolite, tellurosugar was not detected by an inductively coupled plasma-mass spectrometer hyphenated with an HPLC. Speciation studies revealed that the major metabolic pathway of antimony is oxidation in human and rat, and methylation also occurs as a minor metabolic pathway in humans. PMID:19822961

Ogra, Yasumitsu

2009-10-01

333

Formulation and analysis of food-grade mineral hydrocarbons in toxicology studies.  

PubMed

Methods are presented for the formulation and rapid determination of mineral hydrocarbons (MHCs) in animal diet and tissue. Food grade white oils and low melting point waxes are mixed as liquids with powdered diet. Higher melting point waxes are first powdered using a novel atomization technique before dry mixing with diet. MHCs sufficiently soluble in carbon tetrachloride (CCl4) are determined in diet by ultrasonic solvent extraction, adsorption of polar material on Florisil and analysis of the residue by quantitative Fourier Transform Infra Red (FT-IR) spectroscopy. Quantification in tissue is achieved by aqueous saponification, followed by extraction, clean-up and FT-IR analysis as for diet samples. A 10-fold increase in sensitivity over previous methods is achieved, below 0.002% (w/w) in diet and 0.1 mg/g in tissue. Over 80% of the CCl4 used can be recovered and recycled. Control diet seems to contain approximately 0.003% (w/w) background MHC. The method was modified for one powdered wax, only sparingly soluble in CCl4, high concentrations being extracted from diet by flotation in aqueous cetrimide and determined gravimetrically with a limit of detection of 0.1% (w/w) in diet. Application of these methods to 90-day feeding studies is described, and future developments due to the phasing out of CCl4 are discussed. PMID:8045462

Walters, D G; Sherrington, K V; Worrell, N; Riley, R A

1994-06-01

334

Repeated dose (14 days) rat intramuscular toxicology study of Her1 vaccine.  

PubMed

Our goal was to assess the toxicity of two strengths (200 and 400 ?g) of HER1 cancer vaccine (Center of Molecular Immunology, Cuba), presented in two different formulations, in Sprague Dawley rats after repeated intramuscular administration (14 days). Four groups (5 animals/sex) were established: Control, Placebo (adjuvant), and two Treated groups receiving a dose representing ten times of human total dose (10×), 28.6 and 57.1 ?g/kg. Clinical observations, body weight and rectal temperature were measured during the study. Clinical pathology analysis was performed, besides gross necropsy and histological examination of tissues on animals at the end of the assay. The assay ended with a 100% survival. Injection site damage, with the presence of cysts and granulomas, was observed in adjuvant and vaccine treated groups, with most severe cases predominating at higher strength. Administration of Placebo and Her1 vaccine induced increase in polymorphonuclear cells, with relative lymphopenia conditioned by primary neutrophilia. In summary, results suggest that Her1 immunization was capable of inducing an inflammatory effect at the injection site, leading to systemic alterations, more significant at higher strength (400 ?g, 57.1 ?g/kg), probably affected by the immunizations' schedule used. The vaccine was shown to be well tolerated without any obvious signs of systemic toxicity, with findings largely attributable to the adjuvant used. PMID:23085371

Mancebo, A; Casacó, A; Sánchez, B; González, B; Gómez, D; León, A; Bada, A M; Arteaga, M E; González, Y; González, C; Pupo, M; Fuentes, Dasha

2012-10-17

335

Toxicology as a nanoscience? - Disciplinary identities reconsidered  

PubMed Central

Toxicology is about to establish itself as a leading scientific discipline in addressing potential health effects of materials on the nanosize level. Entering into a cutting-edge field, has an impact on identity-building processes within the involved academic fields. In our study, we analyzed the ways in which the entry into the field of nanosciences impacts on the formation of disciplinary identities. Using the methods of qualitative interviews with particle toxicologists in Germany, Holland, Switzerland and the USA, we could demonstrate that currently, toxicology finds itself in a transitional phase. The development of its disciplinary identity is not yet clear. Nearly all of our interview partners stressed the necessity of repositioning toxicology. However, they each suggested different approaches. While one part is already propagandizing the establishment of a new discipline – 'nanotoxicology'- others are more reserved and are demanding a clear separation of traditional and new research areas. In phases of disciplinary new-orientation, research communities do not act consistently. Rather, they establish diverse options. By expanding its disciplinary boundaries, participating in new research fields, while continuing its previous research, and only vaguely defining its topics, toxicology is feeling its way into the new fields without giving up its present self-conception. However, the toxicological research community is also discussing a new disciplinary identity. Within this, toxicology could develop from an auxiliary into a constitutive position, and take over a basic role in the cognitive, institutional and social framing of the nanosciences.

Kurath, Monika; Maasen, Sabine

2006-01-01

336

Preclinical Molecular Imaging of Tumor Angiogenesis  

PubMed Central

Angiogenesis, a course that new blood vessels grow from the existing vasculature, plays important roles both physiologically and pathologically. Angiogenesis can be switched on by growth factors secreted by tumor cells, and in turn supplies more oxygen and nutrition to the tumor. More and more preclinical studies and clinical trials have shown that inhibition of angiogenesis is an effective way to inhibit tumor growth, substantiating the development of anti-angiogenesis therapeutics. Imaging technologies accelerate the translation of preclinical research to the clinic. In oncology, various imaging modalities are widely applied to drug development, tumor early detection and therapy response monitoring. So far, several angiogenesis related imaging agents are promising in cancer diagnosis. However, more effective imaging agents with less side-effect still need to be pursued to visualize angiogenesis process non-invasively. The main purpose of this review is to summarize the recent progresses in preclinical molecular imaging of angiogenesis and to discuss the potential of the current preclinical probes specific to various angiogenesis targets including vascular endothelial growth factor and its receptors (VEGF/VEGFRs), integrin ?v?3 and matrix metalloproteinases (MMPs). It is predicable that related investigations in the field will benefit cancer research and quicken the anti-angiogenic drug development.

Zhu, Lei; Niu, Gang; Fang, Xuexun; Chen, Xiaoyuan

2010-01-01

337

Toxicology and Carcinogenesis Studies of HC Yellow 4 (Cas No. 59820-43-8) in F344/N Rats and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies were conducted by feeding groups of 70 male rats diets containing 0, 2,500 or 5,000 ppm HC Yellow 4 and feeding groups of 70 female rats and 70 mice of each sex diets containing 0, 5,000 or 10,000 ppm HC Yell...

1992-01-01

338

Toxicology and Carcinogenesis Studies of Rhodamine 6G (C.I. Basic Red 1) (CAS NO. 989-38-8) in F344/N Rats and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies were conducted by administering rhodamine 6G in feed to groups of 50 rats of each sex at doses, of 0, 120, or 250 ppm rhodamine 6G for 103 weeks. Groups of 50 male mice received diets containing 0, 1,000, or 2,000 ppm...

J. E. French

1989-01-01

339

NTP Technical Report on the Toxicology and Carcinogenesis Studies of Androstenedione (CAS NO. 63-05-8) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Androstenedione is an androgen steroid that is normally synthesized within men and women and may be metabolized to a more potent androgen or estrogen hormone. It was nominated to the National Toxicology Program for study due to concern for adverse health ...

2010-01-01

340

Toxicology and Carcinogenesis Studies of 4,4'-Diamino-2,2'-Stilbenedisulfonic Acid, Disodium Salt (Cas No. 7336-20-1) in F344/N Rats and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies were conducted by administering 4,4'-diamino-2,2'-stilbenedisulfonic acid, disodium salt, to groups of 60 rats and 60 mice of each sex in feed for 7 days a week for up to 103 weeks. Rats received feed contain...

1992-01-01

341

NTP Technical Report on Toxicology and Carcinogenesis Studies of Tricresyl Phosphate (CAS No. 1330-78-5) in F344/N Rats and B6C3F1 Mice (Gavage and Feed Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenicity studies were conducted by administering tricresyl phosphate in feed to groups of 95 F344/N rats of each sex at doses 0, 75, 150, or 300 ppm for 2 years. An additional group of 95 F344/N rats of each sex were given a dose of ...

1994-01-01

342

NTP Technical Report Series on Toxicology and Carcinogenesis Studies of Furan (CAS No. 110-00-9) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies were conducted by administering to groups 70 rats or each sex 2, 4, or 8 mg furan per kg body weight in corn oil by gavage 5 days per week for 2 years. Groups of 50 mice of each sex received doses of 8 or 15 mg/kg fur...

1993-01-01

343

Aviation combustion toxicology: an overview.  

PubMed

Aviation combustion toxicology is a subspecialty of the field of aerospace toxicology, which is composed of aerospace and toxicology. The term aerospace, that is, the environment extending above and beyond the surface of the Earth, is also used to represent the combined fields of aeronautics and astronautics. Aviation is another term interchangeably used with aerospace and aeronautics and is explained as the science and art of operating powered aircraft. Toxicology deals with the adverse effects of substances on living organisms. Although toxicology borrows knowledge from biology, chemistry, immunology, pathology, physiology, and public health, the most closely related field to toxicology is pharmacology. Economic toxicology, environmental toxicology, and forensic toxicology, including combustion toxicology, are the three main branches of toxicology. In this overview, a literature search for the period of 1960-2007 was performed and information related to aviation combustion toxicology collected. The overview included introduction; combustion, fire, and smoke; smoke gas toxicity; aircraft material testing; fire gases and their interactive effects; result interpretation; carboxyhemoglobin and blood cyanide ion levels; pyrolytic products of aircraft engine oils, fluids, and lubricants; and references. This review is anticipated to be an informative resource for aviation combustion toxicology and fire-related casualties. PMID:20109297

Chaturvedi, Arvind K

344

Pharmacology / Toxicology Review Memorandum - Berinert ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... Pharmacology / Toxicology Review Memorandum ... Comment: The current labeling does not contain a non-clinical toxicology section. ... More results from www.fda.gov/downloads/biologicsbloodvaccines/bloodbloodproducts

345

From quantal counts to mechanisms and systems: the past, present, and future of biometrics in environmental toxicology.  

PubMed

As appreciation for human impact on the environment has developed, so have the experimental systems and associated statistical tools that quantify this impact. Toxicological study in particular has grown in its complexity and its need for advanced statistical support. Within this perspective, we describe statistical practice in environmental toxicology and risk assessment. We present two case studies, one from mammalian toxicology and one from aquatic toxicology, that highlight the evolution of statistical practice in environmental toxicology. PMID:10877286

Bailer, A J; Piegorsch, W W

2000-06-01

346

Toxicology of nanoparticles.  

PubMed

While nanotechnology and the production of nanoparticles are growing exponentially, research into the toxicological impact and possible hazard of nanoparticles to human health and the environment is still in its infancy. This review aims to give a comprehensive summary of what is known today about nanoparticle toxicology, the mechanisms at the cellular level, entry routes into the body and possible impacts to public health. Proper characterisation of the nanomaterial, as well as understanding processes happening on the nanoparticle surface when in contact with living systems, is crucial to understand possible toxicological effects. Dose as a key parameter is essential in hazard identification and risk assessment of nanotechnologies. Understanding nanoparticle pathways and entry routes into the body requires further research in order to inform policy makers and regulatory bodies about the nanotoxicological potential of certain nanomaterials. PMID:21925220

Elsaesser, Andreas; Howard, C Vyvyan

2011-09-08

347

Preclinical Dose-Finding Study With a Liver-Tropic, Recombinant AAV-2/8 Vector in the Mouse Model of Galactosialidosis  

PubMed Central

Galactosialidosis (GS) is a lysosomal storage disease linked to deficiency of the protective protein/cathepsin A (PPCA). Similarly to GS patients, Ppca-null mice develop a systemic disease of the reticuloendothelial system, affecting most visceral organs and the nervous system. Symptoms include severe nephropathy, visceromegaly, infertility, progressive ataxia, and shortened life span. Here, we have conducted a preclinical, dose-finding study on a large cohort of GS mice injected intravenously at 1 month of age with increasing doses of a GMP-grade rAAV2/8 vector, expressing PPCA under the control of a liver-specific promoter. Treated mice, monitored for 16 weeks post-treatment, had normal physical appearance and behavior without discernable side effects. Despite the restricted expression of the transgene in the liver, immunohistochemical and biochemical analyses of other systemic organs, serum, and urine showed a dose-dependent, widespread correction of the disease phenotype, suggestive of a protein-mediated mechanism of cross-correction. A notable finding was that rAAV-treated GS mice showed high expression of PPCA in the reproductive organs, which resulted in reversal of their infertility. Together these results support the use of this rAAV-PPCA vector as a viable and safe method of gene delivery for the treatment of systemic disease in non-neuropathic GS patients.

Hu, Huimin; Gomero, Elida; Bonten, Erik; Gray, John T; Allay, Jim; Wu, Yanan; Wu, Jianrong; Calabrese, Christopher; Nienhuis, Arthur; d'Azzo, Alessandra

2012-01-01

348

Uruguay eHealth initiative: preliminary studies regarding an integrated approach to evaluate vascular age and preclinical atherosclerosis (CUiiDARTE project).  

PubMed

In this work we present an initiative to develop a national (Uruguayan) program to evaluate vascular age and to detect pre-clinical atherosclerosis using: gold-standard technologies; complimentary and integrative approaches to asses arterial functional and structural indexes; data bases systems to process, analyze and determine normal and reference values and to identify the most sensitive markers of vascular changes for different ages. We evaluated, in a Uruguayan population complementary structural and functional vascular parameters that associate aging-related changes and are considered markers of sub-clinical atherosclerosis. Traditional CV risk factors were assessed. The subjects (n=281) were submitted to non-invasive vascular studies to evaluate: 1) Common carotid artery (CCA) intima-media thickness and diameter waveforms, 2) CCA stiffness, 3) aortic stiffness (pulse wave velocity) and 4) peripheral and central pressure pulse wave derived parameters. Age groups: 21-30, 31-40, 41-50, 51-60, and 61-70 years-old. Age-related profiles were obtained for the different vascular parameters, and their utility to assess vascular changes in young, middle-aged and old subjects was evaluated. The work has the strength of being the first that uses, in Latin-America an integrative approach to characterize vascular aging-related changes. PMID:22254442

Armentano, Ricardo L; Bia, Daniel; Zócalo, Yanina; Torrado, Juan; Farro, Ignacio; Farro, Federico; Florio, Lucía; Olascoaga, Alicia; Alallon, Walter; Negreira, Carlos; Lluberas, Ricardo

2011-01-01

349

Transplantation of umbilical cord-derived mesenchymal stem cells as a novel strategy to protect the central nervous system: technical aspects, preclinical studies, and clinical perspectives.  

PubMed

The prevention of perinatal neurological disabilities remains a major challenge for public health, and no neuroprotective treatment to date has proven clinically useful in reducing the lesions leading to these disabilities. Efforts are, therefore, urgently needed to test other neuroprotective strategies including cell therapies. Although stem cells have raised great hopes as an inexhaustible source of therapeutic products that could be used for neuroprotection and neuroregeneration in disorders affecting the brain and spinal cord, certain sources of stem cells are associated with potential ethical issues. The human umbilical cord (hUC) is a rich source of stem and progenitor cells including mesenchymal stem cells (MSCs) derived either from the cord or from cord blood. hUC MSCs (hUC-MSCs) have several advantages as compared to other types and sources of stem cells. In this review, we will summarize the most recent findings regarding the technical aspects and the preclinical investigation of these promising cells in neuroprotection and neuroregeneration, and their potential use in the developing human brain. However, extensive studies are needed to optimize the administration protocol, safety parameters, and potential preinjection cell manipulations before designing a controlled trial in human neonates. PMID:22430384

Dalous, Jérémie; Larghero, Jérome; Baud, Olivier

2012-02-08

350

NTP Toxicology and Carcinogenesis Studies of Ethylene Glycol (CAS No. 107-21-1) in B6C3F1 Mice (Feed Studies).  

PubMed

Ethylene glycol is a major constituent of motor vehicle antifreeze-coolant fluids and is also found in other commercial products including hydraulic brake fluids, adhesives, printer's inks, and wood stains. It is used in the manufacture of polyester films and fibers, polyethylene terephthalate (PET) solid state resins, plasticizers, elastomers, cellophane, and other products. Previous 13-week and 2-year studies of ethylene glycol in F344 rats were considered adequate to evaluate the toxicology and carcinogenicity of ethylene glycol in this species and strain; therefore, the present studies were conducted in mice only. Toxicology and carcinogenesis studies were conducted by administering ethylene glycol (greater than 99% pure) in feed to male and female B6C3F1 mice for 13 weeks and 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, mouse lymphoma L5178Y cells, and Chinese hamster ovary cells. 13-Week Studies: Groups of 10 male and 10 female mice received feed containing 0, 3,200, 6,300, 12,500, 25,000 or 50,000 ppm ethylene glycol. All mice survived to the end of the studies. Final mean body weights of dosed male and female mice and feed consumption of dosed males were similar to those of the controls. Feed consumption of dosed females was significantly greater than that of controls. Absolute and relative organ weights of mice administered ethylene glycol were generally similar to those of controls throughout the study. No chemical-related clinical findings were observed. Chemical-related kidney and liver lesions, seen only in 25,000 and 50,000 ppm male mice, consisted of nephropathy and centrilobular hepatocellular hyaline degeneration (cytoplasmic accumulation of non-birefringent, eosinophilic, globular, or crystalline material resembling erythrocyte fragments). 2-Year Studies: Groups of 60 mice received diets containing ethylene glycol for up to 103 weeks (males: 0, 6,250, 12,500, or 25,000 ppm; females: 0, 12,500, 25,000, or 50,000 ppm). These concentrations correspond to daily doses of approximately 1,500, 3,000, or 6,000 mg/kg body weight for male mice and 3,000, 6,000, or 12,000 mg/kg for females. Dietary concentrations greater than 50,000 ppm have the potential to affect the nutritional value of the feed. Interim evaluations were performed on six males and nine or ten females from each dose group at 15 months. Survival, Body Weights, Feed Consumption, and Clinical Findings in the 2-Year Studies: At the end of the 2-year studies, survival rates of male and female mice exposed to ethylene glycol were similar to those of controls. Mean body weights and feed consumption of exposed male and female groups were also similar to those of controls. No clinical findings associated with the administration of ethylene glycol were observed. Pathology Findings: No chemical-related neoplasms were observed in male or female mice in these studies. Hepatocellular hyaline degeneration was seen in mid- and high-dose male and high-dose female mice. Pulmonary arterial medial hyperplasia was observed at an increased incidence in exposed females but not in exposed males. Incidence and severity of nephropathy were not affected by treatment in either sex. Small numbers of oxalate-like crystals, calculi, or both were noted in renal tubules, urethrae, and/or urinary bladders in a few high-dose male mice. Genetic Toxicology: Ethylene glycol did not induce gene mutations in Salmonella typhimurium strains TA98, TA100, TA1535, and TA1537, trifluorothymidine resistance in mouse L5178Y lymphoma cells, or sister chromatid exchanges or chromosomal aberrations in Chinese hamster ovary cells. All tests were conducted with and without exogenous metabolic activation (S9). Conclusions: Under the conditions of these 2-year feed studies, there was no evidence of carcinogenic activity of ethylene glycol in male B6C3F1 mice receiving 6,250, 12,500, or 25,000 ppm, or in female B6C3F1 mice receiving 12,500, 25,000, or 50,000 ppm. Administration of ethylene glycol resulted in hepatocellular hyaline degeneration in male mice fed diets d

1993-02-01

351

Innovations in testing strategies in reproductive toxicology.  

PubMed

Toxicological hazard assessment currently finds itself at a crossroads where the existing classical test paradigm is challenged by a host of innovative approaches. Animal study protocols are being enhanced for additional parameters and improved for more efficient effect assessment with reduced animal numbers. Whilst existing testing paradigms have generally proven conservative for chemical safety assessment, novel alternative in silico and in vitro approaches and assays are being introduced that begin to elucidate molecular mechanisms of toxicity. Issues such as animal welfare, alternative assay validation, endocrine disruption, and the US-NAS report on toxicity testing in the twenty-first century have provided directionality to these developments. The reductionistic nature of individual alternative assays requires that they be combined in a testing strategy in order to provide a complete picture of the toxicological profile of a compound. One of the challenges of this innovative approach is the combined interpretation of assay results in terms of toxicologically relevant effects. Computational toxicology aims at providing that integration. In order to progress, we need to follow three steps: (1) Learn from past experience in animal studies and human diseases about critical end points and pathways of toxicity. (2) Design alternative assays for essential mechanisms of toxicity. (3) Build an integrative testing strategy tailored to human hazard assessment using a battery of available alternative tests for critical end points that provides optimal in silico and in vitro filters to upgrade toxicological hazard assessment to the mechanistic level. PMID:23138915

Piersma, Aldert H

2013-01-01

352

Testing computational toxicology models with phytochemicals.  

PubMed

Computational toxicology employing quantitative structure-activity relationship (QSAR) modeling is an evidence-based predictive method being evaluated by regulatory agencies for risk assessment and scientific decision support for toxicological endpoints of interest such as rodent carcinogenicity. Computational toxicology is being tested for its usefulness to support the safety assessment of drug-related substances (e.g. active pharmaceutical ingredients, metabolites, impurities), indirect food additives, and other applied uses of value for protecting public health including safety assessment of environmental chemicals. The specific use of QSAR as a chemoinformatic tool for estimating the rodent carcinogenic potential of phytochemicals present in botanicals, herbs, and natural dietary sources is investigated here by an external validation study, which is the most stringent scientific method of measuring predictive performance. The external validation statistics for predicting rodent carcinogenicity of 43 phytochemicals, using two computational software programs evaluated at the FDA, are discussed. One software program showed very good performance for predicting non-carcinogens (high specificity), but both exhibited poor performance in predicting carcinogens (sensitivity), which is consistent with the design of the models. When predictions were considered in combination with each other rather than based on any one software, the performance for sensitivity was enhanced, However, Chi-square values indicated that the overall predictive performance decreases when using the two computational programs with this particular data set. This study suggests that complementary multiple computational toxicology software need to be carefully selected to improve global QSAR predictions for this complex toxicological endpoint. PMID:20024931

Valerio, Luis G; Arvidson, Kirk B; Busta, Emily; Minnier, Barbara L; Kruhlak, Naomi L; Benz, R Daniel

2010-02-01

353

Advanced Urine Toxicology Testing  

Microsoft Academic Search

Urine toxicology screening testing is an important standard of care in the addiction and pain treatment setting, offering a reproducible, unbiased, and accurate laboratory test to monitor patients and provide objective support for clinical observations. It has been shown that physicians do not have proficiency in the ordering or interpretation of these tests. This article is an attempt to respond

Peter L. Tenore

2010-01-01

354

Toxicology, an STS Approach.  

ERIC Educational Resources Information Center

Presented are activities suggested through Project L.A.B.S. that involve the topic of toxicology. Activities include suggested research, the risk benefit seesaw, human-made compounds, legislation, a historical perspective, and health. A suggested readings list is provided. (KR)

Wagner, Richard

1990-01-01

355

Toxicology and Chemical Safety.  

ERIC Educational Resources Information Center

Topics addressed in this discussion of toxicology and chemical safety include routes of exposure, dose/response relationships, action of toxic substances, and effects of exposure to chemicals. Specific examples are used to illustrate the principles discussed. Suggests prudence in handling any chemicals, whether or not toxicity is known. (JN)

Hall, Stephen K.

1983-01-01

356

Toxicology, an STS Approach.  

ERIC Educational Resources Information Center

|Presented are activities suggested through Project L.A.B.S. that involve the topic of toxicology. Activities include suggested research, the risk benefit seesaw, human-made compounds, legislation, a historical perspective, and health. A suggested readings list is provided. (KR)|

Wagner, Richard

1990-01-01

357

Toxicology and Chemical Safety.  

ERIC Educational Resources Information Center

|Topics addressed in this discussion of toxicology and chemical safety include routes of exposure, dose/response relationships, action of toxic substances, and effects of exposure to chemicals. Specific examples are used to illustrate the principles discussed. Suggests prudence in handling any chemicals, whether or not toxicity is known. (JN)|

Hall, Stephen K.

1983-01-01

358

Toxicology of Melatonin  

Microsoft Academic Search

Despite the fact that melatonin has been released for public use in the United States by the Food and Drug Administration and is available over the counter nationwide, there currently is a total lack of information on the toxicology of melatonin. In Europe, melatonin has a completely different status in that it is considered a \\

Béatrice Guardiola-Lemaitre

1997-01-01

359

The minipig in toxicology  

Microsoft Academic Search

The use of pigs (Sus scrofa) in biomedical research is well established in particular in surgical and physiological research. For years both pigs and minipigs have been used in pharmacology and toxicology to answer specific questions when the more conventional species have been found unsuitable. The development of minipigs has resulted in strains of more manageable size than the domestic

Ove Svendsen

2006-01-01

360

Toxicology and seafood toxins: domoic acid.  

PubMed

Marine and terrestrial food sources are susceptible to contamination by various industrial chemicals and microbial pathogens. Both types of hazard are amenable to regulatory assessment using a single toxicology data base, along with some knowledge of contaminant levels and consumption figures for food. On the other hand, regulatory problems persist with acutely toxic naturally occurring phycotoxins, which may accumulate unpredictably to toxic levels in seafood. However, a scarce supply of pure toxin often precludes the availability of acceptable toxicology studies describing their biological effects. An exception to this situation is domoic acid, a neurotoxin phycotoxin that produced numerous cases of severe human intoxication which demanded extensive toxicological study. This paper describes a series of ongoing studies initiated in the wake of the outbreak of domoic acid toxicity that occurred in 1987 in Eastern Canada. PMID:7866671

Iverson, F; Truelove, J

1994-01-01

361

The role of childhood trauma in the neurobiology of mood and anxiety disorders: preclinical and clinical studies  

Microsoft Academic Search

Epidemiologic studies indicate that children exposed to early adverse experiences are at increased risk for the development of depression, anxiety disorders, or both. Persistent sensitization of central nervous system (CNS) circuits as a consequence of early life stress, which are integrally involved in the regulation of stress and emotion, may represent the underlying biological substrate of an increased vulnerability to

Christine Heim; Charles B. Nemeroff

2001-01-01

362

Toxicological evaluation of pidotimod.  

PubMed

This paper reports the toxicological evaluation of pidotimod ((R)-3-[(S)-(5-oxo-2-pyrrolidinyl) carbonyl]-thiazolidine-4-carboxylic acid, PGT/1A, CAS 121808-62-6). Its acute toxicity in mice, rats and dogs was very low after oral, i.v., i.m. and i.p. administration. The repeated administration studies in rats were performed for 4 months via the i.p. route and for 12 months via the oral route. Pidotimod did not show toxic effects at dosages up to 200 mg/kg i.p. and 800 mg/kg p.o. These dosages correspond to 32.5 times the maximum dosage intended for clinical use. The repeated administration studies in dogs were performed for 26 weeks via the i.m. route and for 52 weeks via the oral route. Pidotimod did not show toxic effects at dosages up to 300 mg/kg i.m. and 600 mg/kg p.o.. It did not affect male or female rat fertility at dosages up to 600 mg/kg by oral and 500 mg/kg by i.v. route. The compound was not teratogenic in rats (600 mg/kg p.o. and 1000 mg/kg i.v.), with no effects on subsequent embryofoetal development at dosages up to 1000 mg/kg/day, and in rabbits (300 mg/kg p.o. and 500 mg/kg. i.v.). There were no peri- and postnatal toxic effects in rats (600 mg/kg p.o. and 500 mg/kg i.v.). Local tolerability of pidotimod after i.m. administration was very good. In conclusion pidotimod is characterized by a high safety margin in all animal species. PMID:7857340

Coppi, G; Amico-Roxas, M; Bertè, F; Bussi, R; Gnemi, P; Harling, R J; Mailland, F; Manzardo, S; Massey, J E; Spencer-Briggs, D J

1994-12-01

363

National Toxicology Program Annual Report for Fiscal Year 2008.  

National Technical Information Service (NTIS)

In 2008 the National Toxicology Program (NTP) celebrated its 30th anniversary as a leader in the effort to apply the science of toxicology to the protection of public health. During its history, the NTP has studied more than 2,500 substances for toxicity ...

2009-01-01

364

Targeting therapy of hepatocellular carcinoma with doxorubicin prodrug PDOX increases anti-metastatic effect and reduces toxicity: a preclinical study  

PubMed Central

Background This study was to investigate the effects and safety of cathepsin B-cleavable doxorubicin (DOX)-prodrug (PDOX) for targeting therapy of metastatic human hepatocellular carcinoma (HCC) using DOX as a positive control drug. Methods The orthotopic nude mice model of highly metastatic HCC was established and the animals were randomized and treated with PDOX, DOX and saline, respectively. Hematology, biochemistry and tumor markers were studied. At autopsy, liver tumor weight and size, ascites, abdominal lymph nodes metastases, experimental peritoneal carcinomatosis index (ePCI), and tumor-host body weight ratio were investigated. Immunohistochemical studies and western blotting were done to investigate key molecules involved in the mechanism of action. Results Compared with Control, both PDOX and DOX could similarly and significantly reduce liver tumor weight and tumor volume by over 40%, ePCI values, retroperitoneal lymph node metastases and lung metastases and serum AFP levels (P?

2013-01-01

365

Preclinical efficacy studies of a novel nanoparticle-based formulation of paclitaxel that out-performs Abraxane  

Microsoft Academic Search

Purpose  Poly-(?-l-glutamylglutamine)–paclitaxel (PGG–PTX) is a novel polymer-based formulation of paclitaxel (PTX) in which the PTX is linked\\u000a to the polymer via ester bonds. PGG–PTX is of interest because it spontaneously forms very small nanoparticles in plasma.\\u000a In mouse models, PGG–PTX increased tumor exposure to PTX by 7.7-fold relative to that produced by PTX formulated in Cremophor.\\u000a In this study, the efficacy

Zhongling Feng; Gang Zhao; Lei Yu; David Gough; Stephen B. Howell

2010-01-01

366

Orazipone, a locally acting immunomodulator, ameliorates intestinal radiation injury: A preclinical study in a novel rat model  

SciTech Connect

Purpose: Intestinal radiation injury (radiation enteropathy) is relevant to cancer treatment, as well as to radiation accidents and radiation terrorism scenarios. This study assessed the protective efficacy of orazipone, a locally-acting small molecule immunomodulator. Methods and Materials: Male rats were orchiectomized, a 4-cm segment of small bowel was sutured to the inside of the scrotum, a proximal anteperistaltic ileostomy was created for intraluminal drug administration, and intestinal continuity was re-established by end-to-side anastomosis. After three weeks postoperative recovery, the intestine in the 'scrotal hernia' was exposed locally to single-dose or fractionated X-radiation. Orazipone (30 mg/kg/day) or vehicle was administered daily through the ileostomy, either during and after irradiation, or only after irradiation. Structural, cellular, and molecular aspects of intestinal radiation toxicity were assessed two weeks after irradiation. Results: Orazipone significantly ameliorated histologic injury and transforming growth factor-{beta} immunoreactivity levels, both after single-dose and fractionated irradiation. Intestinal wall thickness was significantly reduced after single-dose and nonsignificantly after fractionated irradiation. Mucosal surface area and numbers of mast cells were partially restored by orazipone after single-dose irradiation. Conclusions: This work (1) demonstrates the utility of the ileostomy rat model for intraluminal administration of response modifiers in single-dose and fractionated radiation studies; (2) shows that mucosal immunomodulation during and/or after irradiation ameliorates intestinal toxicity; and (3) highlights important differences between single-dose and fractionated radiation regimens.

Boerma, Marjan [Department of Surgery, University of Arkansas for Medical Sciences and Central Arkansas Veterans Healthcare System, Little Rock, AR (United States); Wang, Junru [Department of Surgery, University of Arkansas for Medical Sciences and Central Arkansas Veterans Healthcare System, Little Rock, AR (United States); Richter, Konrad K. [Department of Surgery, University of Arkansas for Medical Sciences and Central Arkansas Veterans Healthcare System, Little Rock, AR (United States); Hauer-Jensen, Martin [Department of Surgery, University of Arkansas for Medical Sciences and Central Arkansas Veterans Healthcare System, Little Rock, AR (United States) and Department of Pathology, University of Arkansas for Medical Sciences and Central Arkansas Veterans Healthcare System, Little Rock, AR (United States)]. E-mail: mhjensen@life.uams.edu

2006-10-01

367

Preclinical Alzheimer disease --the challenges ahead  

PubMed Central

There is growing recognition that the pathophysiological process of Alzheimer disease (AD) begins many years prior to clinically obvious symptoms, and the concept of a presymptomatic or preclinical stage of AD is becoming more widely accepted. Advances in biomarker studies have enabled detection of AD pathology in vivo in clinically normal older individuals. The predictive value of these biomarkers at the individual patient level, however, remains to be elucidated. The ultimate goal of identifying individuals in the preclinical stages of AD is to facilitate early intervention to delay and perhaps even prevent emergence of the clinical syndrome. A number of challenges remain to be overcome before this concept can be validated and translated into clinical practice.

Sperling, Reisa A.; Karlawish, Jason; Johnson, Keith A.

2013-01-01

368

Fibrillar amyloid correlates of preclinical cognitive decline.  

PubMed

BACKGROUND: It is not known whether preclinical cognitive decline is associated with fibrillar ?-amyloid (A?) deposition irrespective of apolipoprotein E (APOE) ?4 status. METHODS: From a prospective observational study of 623 cognitively normal individuals, we identified all subjects who showed preclinical decline of at least 2 standard deviations beyond the decline of the entire group in memory or executive function. Fourteen decliners were matched by APOE ?4 gene dose, age, sex, and education with 14 nondecliners. Dynamic Pittsburgh compound B (PiB) positron emission tomography (PET) scans, the Logan method, statistical parametric mapping, and automatically labeled regions of interest were used to characterize and compare cerebral-to-cerebellar PiB distribution volume ratios (DVRs), reflecting fibrillar A? burden. RESULTS: At P < .005 (uncorrected), decliners had significantly greater DVRs in comparison to nondecliners. CONCLUSIONS: Asymptomatic longitudinal neuropsychological decline is associated with subsequent increased fibrillar amyloid deposition, even when controlling for APOE ?4 genotype. PMID:23583233

Stonnington, Cynthia M; Chen, Kewei; Lee, Wendy; Locke, Dona E C; Dueck, Amylou C; Liu, Xiaofen; Roontiva, Auttawut; Fleisher, Adam S; Caselli, Richard J; Reiman, Eric M

2013-04-11

369

Discovery and preliminary confirmation of novel early detection biomarkers for triple-negative breast cancer using preclinical plasma samples from the Women's Health Initiative observational study  

PubMed Central

Triple-negative breast cancer is a particularly aggressive and lethal breast cancer subtype that is more likely to be interval-detected rather than screen-detected. The purpose of this study is to discover and initially validate novel early detection biomarkers for triple-negative breast cancer using preclinical samples. Plasma samples collected up to 17 months prior to diagnosis from 28 triple-negative cases and 28 matched controls from the Women’s Health Initiative Observational Study were equally divided into a training set and a test set and interrogated using a customized antibody array. Data were available on 889 antibodies, and in the training set statistically significant differences in case vs. control signals were observed for 93 (10.5%) antibodies at p<0.05. Of these 93 candidates, 29 were confirmed in the test set at p<0.05. Areas under the curve for these candidates ranged from 0.58 to 0.79. With specificity set at 98%, sensitivity ranged from 4% to 68% with ?20 candidates having a sensitivity 20% and 6 having a sensitivity ?40%. In an analysis of KEGG gene sets, the pyrimidine metabolism gene set was upregulated in cases compared to controls (p=0.004 in the testing set) and the JAK/Stat signaling pathway gene set was downregulated (p=0.003 in the testing set). Numerous potential early detection biomarkers specific to triple-negative breast cancer in multiple pathways were identified. Further research is required to follow-up on promising candidates in larger sample sizes and to better understand their potential biological importance as our understanding of the etiology of triple-negative breast cancer continues to grow.

Li, Christopher I.; Mirus, Justin E.; Zhang, Yuzheng; Ramirez, Arturo B.; Ladd, Jon J.; Prentice, Ross L.; McIntosh, Martin; Hanash, Samir M.; Lampe, Paul D.

2012-01-01

370

A rapid and sensitive LC-MS/MS assay for the determination of berbamine in rat plasma with application to preclinical pharmacokinetic study.  

PubMed

Berbamine (BBM), a natural compound from Chinese herb Berberis amurensis, has recently received a great deal of attention due to its anti-leukemia activity. In this study, a rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of BBM in rat plasma was developed for the first time. Caffeine was used as an internal standard. Chromatographic separation was performed on an ODS column with gradient elution using methanol-1% formic acid as mobile phase at a flow rate of 0.3mL/min. Quantification was through tandem mass spectrometry with positive electrospray ionization (ESI) and multiple reaction monitoring (MRM) at m/z 305.2?566.3 and 195.1?138.0 for BBM and IS, respectively. The lower limit of quantification was 1ng/mL with a linear range of 1-1000ng/mL. The intra- and inter-day assay precision (RSD) ranged from 2.0-6.4% to 2.5-5.5%, respectively, and the intra- and inter-day assay accuracy (RE) was between -5.8-6.0% and -6.5-1.4%, respectively. The validated method was successfully applied to the preclinical pharmacokinetic studies of BBM in rats. The elimination half-lives (t1/2) were (472.4±66.1), (509.6±97.0) and (486.2±94.6) min after single intravenous administration of 2, 4 and 8mg/kg BBM, respectively. The area under the plasma concentration versus time curve (AUC0-24h) and initial plasma concentration (C0) were linearly related to dose. PMID:23660248

Liu, Qingwang; Wang, Junsong; Yang, Lei; Jia, Yuanwei; Kong, Lingyi

2013-04-17

371

Standardized extracts from hawthorn leaves and flowers in the treatment of cardiovascular disorders--preclinical and clinical studies.  

PubMed

Extracts from different parts of hawthorn plants (Crataegus spp.) are used worldwide for the treatment of cardiovascular diseases. So far, almost all clinical studies have been conducted with standardized hydroalcoholic extracts from leaves and flowers. These trials with more than 4000 patients have provided evidence for clinical benefits in the therapy of mild chronic heart failure. Besides cardiotonic effects, recent pharmacological investigations indicate that hawthorn extracts also possess cardio- and vasoprotective properties. Thus, these extracts may also be employed in the prophylactic and therapeutic treatment of such conditions as endothelial dysfunction, atherosclerosis, coronary heart disease, or prevention of restenosis/reocclusion following peripheral endovascular treatment. In this review the pharmacological and clinical data relating to these standardized extracts are summarized. PMID:21384315

Koch, Egon; Malek, Fathi Abdul

2011-03-07

372

Fluorine-18-fluorodeoxygglucose-guided breast cancer surgery with a positron-sensitive probe: Validation in preclinical studies  

SciTech Connect

In this study, the feasibility of utilizing 2-deoxy-2-fluoro-d-glucose (FDG) in conjunction with a positron-sensitive intraoperative probe to guide breast tumor excision was investigated. The probe was constructed with a plastic scintillator tip coupled to a photomultiplier tube with fiber optic cable. Anticipated resolution degradation was evaluated by measurement of line spread functions in the presence of background radiation. Realistic photon background distributions were simulated with a human torso phantom and a cardiac insert. The relationship between resolution and energy threshold was measured to find the optimal discriminator settings. In addition, probe sensitivity as a function of energy threshold was determined for various size-simulated tumors. Finally, the ability to localize breast cancers in vivo was tested in a rodent model. Mammary rat tumors implanted in Lewis rats were examined after injection with FDG; these results were correlated with those of histologic analyses. Measurements of line spread functions indicated that resolution could be maximized in a realistic background photon environment by increasing the energy threshold to levels at or above the Compton continuum edge (340 keV). At this setting, the probe`s sensitivity was determined to be 58 and 11 cps/{mu}Ci for 3.18- and 6.35-mm diameter simulated tumors, respectively. Probe readings correlated well with histologic results; the probe was generally able to discriminate between tumor and normal tissue. This study indicates that breast cancer surgery guided by a positron-sensitive probe warrants future evaluation in breast-conserving surgery of patients with breast cancer. 23 refs., 5 figs.

Raylman, R.R.; Fisher, S.J.; Brown, R.S.; Ethier, S.P.; Wahl, R.L. [Univ. of Michigan Medical Center, Ann Arbor, MI (United States)

1995-10-01

373

A comparative study of students' performance in preclinical physiology assessed by multiple choice and short essay questions.  

PubMed

This study was designed to compare the performance of medical students in physiology when assessed by multiple choice questions (MCQs) and short essay questions (SEQs). The study also examined the influence of factors such as age, sex, O/level grades and JAMB scores on performance in the MCQs and SEQs. A structured questionnaire was administered to 264 medical students' four months before the Part I MBBS examination. Apart from personal data of each student, the questionnaire sought information on the JAMB scores and GCE O' Level grades of each student in English Language, Biology, Chemistry, Physics and Mathematics. The physiology syllabus was divided into five parts and the students were administered separate examinations (tests) on each part. Each test consisted of MCQs and SEQs. The performance in MCQs and SEQs were compared. Also, the effects of JAMB scores and GCE O/level grades on the performance in both the MCQs and SEQs were assessed. The results showed that the students performed better in all MCQ tests than in the SEQs. JAMB scores and O' level English Language grade had no significant effect on students' performance in MCQs and SEQs. However O' level grades in Biology, Chemistry, Physics and Mathematics had significant effects on performance in MCQs and SEQs. Inadequate knowledge of physiology and inability to present information in a logical sequence are believed to be major factors contributing to the poorer performance in the SEQs compared with MCQs. In view of the finding of significant association between performance in MCQs and SEQs and GCE O/level grades in science subjects and mathematics, it was recommended that both JAMB results and the GCE results in the four O/level subjects above may be considered when selecting candidates for admission into the medical schools. PMID:11713989

Oyebola, D D; Adewoye, O E; Iyaniwura, J O; Alada, A R; Fasanmade, A A; Raji, Y

374

Toxicological characterization of the landfill leachate prior/after chemical and electrochemical treatment: A study on human and plant cells.  

PubMed

In this research, toxicological safety of two newly developed methods for the treatment of landfill leachate from the Piškornica (Croatia) sanitary landfill was investigated. Chemical treatment procedure combined chemical precipitation with CaO followed by coagulation with ferric chloride and final adsorption by clinoptilolite. Electrochemical treatment approach included pretreatment with ozone followed by electrooxidation/electrocoagulation and final polishing by microwave irradiation. Cell viability of untreated/treated landfill leachate was examined using fluorescence microscopy. Cytotoxic effect of the original leachate was obtained for both exposure periods (4 and 24h) while treated samples showed no cytotoxic effect even after prolonged exposure time. The potential DNA damage of the untreated/treated landfill leachate was evaluated by the comet assay and cytokinesis-block micronucleus (CBMN) assay using either human or plant cells. The original leachate exhibited significantly higher comet assay parameters compared to negative control after 24h exposure. On the contrary, there was no significant difference between negative control and chemically/electrochemically treated leachate for any of the parameters tested. There was also no significant increase in either CBMN assay parameter compared to the negative control following the exposure of the lymphocytes to the chemically or electrochemically treated landfill leachate for both exposure periods while the original sample showed significantly higher number of micronuclei, nucleoplasmic bridges and nuclear buds for both exposure times. Results suggest that both methods are suitable for the treatment of such complex waste effluent due to high removal efficiency of all measured parameters and toxicological safety of the treated effluent. PMID:23790829

Garaj-Vrhovac, Vera; Oreš?anin, Višnja; Gajski, Goran; Geri?, Marko; Ruk, Damir; Kollar, Robert; Radi? Brkanac, Sandra; Cvjetko, Petra

2013-06-20

375

Isolated Lung Perfusion as an Adjuvant Treatment of Colorectal Cancer Lung Metastases: A Preclinical Study in a Pig Model  

PubMed Central

Background The lung is a frequent site of colorectal cancer (CRC) metastases. After surgical resection, lung metastases recurrences have been related to the presence of micrometastases, potentially accessible to a high dose chemotherapy administered via adjuvant isolated lung perfusion (ILP). We sought to determine in vitro the most efficient drug when administered to CRC cell lines during a short exposure and in vivo its immediate and delayed tolerance when administered via ILP. Methods First, efficacy of various cytotoxic molecules against a panel of human CRC cell lines was tested in vitro using cytotoxic assay after a 30-minute exposure. Then, early (operative) and delayed (1 month) tolerance of two concentrations of the molecule administered via ILP was tested on 19 adult pigs using hemodynamic, biological and histological criteria. Results In vitro, gemcitabine (GEM) was the most efficient drug against selected CRC cell lines. In vivo, GEM was administered via ILP at regular (20 µg/ml) or high (100 µg/ml) concentrations. GEM administration was associated with transient and dose-dependant pulmonary vasoconstriction, leading to a voluntary decrease in pump inflow in order to maintain a stable pulmonary artery pressure. After this modulation, ILP using GEM was not associated with any systemic leak, systemic damage, and acute or delayed histological pulmonary toxicity. Pharmacokinetics studies revealed dose-dependant uptake associated with heterogenous distribution of the molecule into the lung parenchyma, and persistent cytotoxicity of venous effluent. Conclusions GEM is effective against CRC cells even after a short exposure. ILP with GEM is a safe and reproducible technique.

Pages, Pierre-Benoit; Facy, Olivier; Mordant, Pierre; Ladoire, Sylvain; Magnin, Guy; Lokiec, Francois; Ghiringhelli, Francois; Bernard, Alain

2013-01-01

376

Pre-clinical study of in vivo magnetic resonance-guided bubble-enhanced heating in pig liver.  

PubMed

Bubble-enhanced heating (BEH) can be exploited to increase heating efficiency in treatment of liver tumors with non-invasive high-intensity focused ultrasound (HIFU). The objectives of this study were: (i) to demonstrate the feasibility of increasing the heating efficiency of sonication exploiting BEH in pig liver in vivo using a clinical platform; (ii) to determine the acoustic threshold for such effects with real-time, motion-compensated magnetic resonance-guided thermometry; and (iii) to compare the heating patterns and thermal lesion characteristics resulting from continuous sonication and sonication including a burst pulse. The threshold acoustic power for generation of BEH in pig liver in vivo was determined using sonication of 0.5-s duration ("burst pulse") under real-time magnetic resonance thermometry. In a second step, experimental sonication composed of a burst pulse followed by continuous sonication (14.5 s) was compared with conventional sonication (15 s) of identical energy (1.8 kJ). Modification of the heating pattern at the targeted region located at a liver depth between 20 and 25 mm required 600-800 acoustic watts. The experimental group exhibited near-spherical heating with 40% mean enhancement of the maximal temperature rise as compared with the conventional sonication group, a mean shift of 7 ± 3.3 mm toward the transducer and reduction of the post-focal temperature increase. Magnetic resonance thermometry can be exploited to control acoustic BEH in vivo in the liver. By use of experimental sonication, more efficient heating can be achieved while protecting tissues located beyond the focal point. PMID:23562012

Elbes, Delphine; Denost, Quentin; Laurent, Christophe; Trillaud, Hervé; Rullier, Anne; Quesson, Bruno

2013-04-03

377

[The opioid tramadol demonstrates excitatory properties of non-opioid character--a preclinical study using alfentanil as a comparison].  

PubMed

Tramadol, an analgesic with mean potency one tenth that of morphine is used regularly for the treatment of chronic and postoperative pain. Previous reports have indicated that tramadol may induce seizure activity when given together with a selective serotonin reuptake inhibitor (SSRI). Therefore, its major mode of action may be questioned which purportedly is due to binding with the opioid receptor and partly due to the inhibition of monoamine reuptake. We therefore set out to study its potential in inducing seizure activity and to quantify its effect on EEG-power spectra and on the central modulation of sensory afferents in awake and trained dogs (n=7). In order to demonstrate if opioid receptors mediated these effects, incremental doses of tramadol were given which was followed by naloxone for possible reversal. After a wash-out period the same animals were exposed to graded doses of alfentanil, a pure mu-receptor agonist. Again this was followed by the opioid antagonist naloxone for reversal.The electroencephalogram (EEG) and the event-related evoked potentials (SEP) were used to demonstrate possible excitatory effects. In order to derive the SEP the front paw was stimulated electrically (Digi Stim II trade mark ) while the evoked potentials were picked up contralaterally from the somatosensory cortex using stick-on electrodes. 256 sweeps were averaged (Lifescan) and the peak-to-peak amplitude was measured to demonstrate CNS excitation compared to control (%). Additionally, the raw electroencephalogram was viewed for epileptogenic changes and its power computed into the various power bands alpha, beta, delta und theta using FFT over a time epoch of 60 s. Following control, graded doses of either tramadol (2-5-10 mg/kg i.v.) or alfentanil (10-30-60 microg/kg i.v.) were given every 15 min while the EEG and the SEP were recorded. Thereafter naloxone (20 microg/kg i.v.) was injected for reversal. Tramadol did not suppress the amplitude of the SEP at any dose. High doses (>5 mg/kg i.v.) resulted in an increase (+100%) of the amplitude of the evoked potential. This was accompanied by short-term muscle fibrillations, and a short-term spike-and-wave activity in the EEG followed by a long-lasting theta-dominance. These effects could not be reversed by naloxone. In contrast to tramadol, alfentanil induced a dose-related depression of amplitude in the SEP with a maximum of 82% suggesting a depressive effect of modulation of afferents in the sensory cortex. This effect was fully naloxone reversible and was followed by a rebound in amplitude of the SEP together with an increase in fast beta-waves in the EEG. Tramadol very little mediates its central action via the mu-opioid receptor as the present effects were not naloxone reversible. Consistent with the results is the very low affinity of tramadol to the opioid receptor which is several thousand times less than that of morphine. Most likely, inhibition of central norepinephrine and serotonin reuptake as well as the reduction in 5-HT-turnover may contribute to the effects of tramadol. Due to the monoamine reuptake inhibition an increase in transmission may result, triggering off excitatory phenomena with spike-and-wave activity in the CNS. Such excitatory effects, however, may only be seen when tramadol is used in doses exceeding the therapeutic range. PMID:12799988

Freye, E; Latasch, L; Von Bredow, G; Neruda, B

1998-02-28

378

Toxicologic methods: controlled human exposures.  

PubMed Central

The assessment of risk from exposure to environmental air pollutants is complex, and involves the disciplines of epidemiology, animal toxicology, and human inhalation studies. Controlled, quantitative studies of exposed humans help determine health-related effects that result from breathing the atmosphere. The major unique feature of the clinical study is the ability to select, control, and quantify pollutant exposures of subjects of known clinical status, and determine their effects under ideal experimental conditions. The choice of outcomes to be assessed in human clinical studies can be guided by both scientific and practical considerations, but the diversity of human responses and responsiveness must be considered. Subjects considered to be among the most susceptible include those with asthma, chronic obstructive lung disease, and cardiovascular disease. New experimental approaches include exposures to concentrated ambient air particles, diesel engine exhaust, combustion products from smoking machines, and experimental model particles. Future investigations of the health effects of air pollution will benefit from collaborative efforts among the disciplines of epidemiology, animal toxicology, and human clinical studies.

Utell, M J; Frampton, M W

2000-01-01

379

NTP Toxicology and Carcinogenesis Studies of C.I. Direct Blue 15 (CAS No. 2429-74-5) in F344 Rats (Drinking Water Studies).  

PubMed

C.I. Direct Blue 15 is one of five chemicals being evaluated in 2-year carcinogenicity and toxicity studies as part of the NTP's Benzidine Dye Initiative. This Initiative was designed to evaluate representative benzidine congeners, benzidine congener-derived dyes, and benzidine-derived dyes. The dye, industrial grade C.I. Direct Blue 15, was chosen for study as a product to which workers are potentially exposed. Because of the high salt content, the dye was desalted prior to use. The purity was determined to be approximately 50%, with high-performance liquid chromatography indicating one major peak and approximately 35 impurities. Toxicology and carcinogenesis studies were conducted by administering the dye, C.I. Direct Blue 15, in drinking water to groups of F344/N rats of each sex for 14 days, 13 weeks, or 22 months. Planned as 24-month studies, the 22-month studies were terminated early because of rapidly declining animal survival, which was due primarily to neoplasia. These studies were performed only in rats because studies of benzidine congeners were being performed in mice at the National Center for Toxicological Research (NCTR). Genetic toxicology studies were conducted in Salmonella typhimurium and Chinese hamster ovary cells. 14-Day Studies: Rats were given C.I. Direct Blue 15 in drinking water at doses of 1,250, 2,500, 5,000, 10,000, or 30,000 ppm. All control and treated rats survived. Body weight gain in high-dose females was less than that in controls. Water consumption declined as the dose increased. Male and female rats receiving 30,000 ppm had slight degeneration and necrosis of individual hepatocytes in the liver, and females also had mild to moderate renal tubule degeneration and thymic lymphoid depletion. 13-Week Studies: C.I. Direct Blue 15 was administered in drinking water at doses of 0, 1,250, 2,500, 5,000, 10,000, or 30,000 ppm to male rats, and at doses of 0, 630, 1,250, 2,500, 5,000, or 10,000 ppm to female rats. Seven of 10 male rats receiving 30,000 ppm died; all rats in the other groups survived until the end of the studies. Mean final body weights of males receiving 10,000 or 30,000 ppm were 92% and 69% of those of controls, and mean final body weights of females receiving 5,000 or 10,000 ppm were 97% and 94% of those of controls. Tissues from treated animals were stained blue. Compound-related lesions were seen in the kidney and liver of male rats given 30,000 ppm and in the kidney of males and females given 10,000 ppm. The renal lesions included necrosis, degeneration, pigmentation and regeneration of the tubule epithelium, and tubule mineralization. Liver lesions included centrilobular hepatocellular degeneration, fatty metamorphosis, and individual cell necrosis with slight periportal hepatocellular hypertrophy. Lymphoid depletion in the thymus was also seen in the high-dose males. Based on the results of the 14-day and 13-week studies, the high dose chosen for the 22-month studies was 2,500 ppm. 22-Month Studies: At study initiation, 70 rats of each sex were given 0 or 2,500 ppm C.I. Direct Blue 15, 45 rats of each sex were given 630 ppm, and 75 rats of each sex were given 1,250 ppm. Interim evaluations were made at 9 and 15 months. The average amounts of compound consumed per day by the six dose groups after week 52 of the studies were estimated to be 45, 90, and 215 mg/kg for male rats and 50, 100, and 200 mg/kg for female rats. Survival and Body Weights: The studies were terminated at 22 months due to extensive mortality associated with chemical-related neoplasia. Survival of control, 630, 1,250, and 2,500 ppm males at 22 months was 37/50, 8/35, 11/65, and 2/50; survival of females was 40/50, 13/35, 22/65, and 4/50. At 22 months, the mean final body weights of the 630, 1,250, and 2,500 ppm groups were 95%, 91%, and 81% of those of the control for male rats and 91% of those of the control for all female dose groups. Histopathologic Effects in the 22-Month Studies: At the 9-month interim evaluations, one adenoma of the Zymbal's gland was seen in a high-dose male rat, and three carcinm

1992-08-01

380

Progress in nickel toxicology  

SciTech Connect

The Third International Conference on Nickel Metabolism and Toxicology was held at the PLM St Jacques Hotel in Paris in September 1984, under the joint sponsorship of the International Union of Pure and Applied Chemistry (IUPAC), the Association of Clinical Scientists, and the Nickel Producers Environmental Research Association (NiPERA). The Paris Conference was attended by 150 participants from 19 countries, including many of the world's authorities on nickel in the areas of trace analysis, biochemistry, radiochemistry, pharmacology, toxicology, pathology, immunology, industrial hygiene, epidemiology, occupational health and clinical medicine. The text of the Richard T. Barton memorial lecture and synopses of the scientific papers that were presented at the Conference are published in this volume.

Brown, S.S.; Sunderman, F.W.

1985-01-01

381

History of wildlife toxicology  

Microsoft Academic Search

The field of wildlife toxicology can be traced to the late nineteenth and early twentieth centuries. Initial reports included\\u000a unintentional poisoning of birds from ingestion of spent lead shot and predator control agents, alkali poisoning of waterbirds,\\u000a and die-offs from maritime oil spills. With the advent of synthetic pesticides in the 1930s and 1940s, effects of DDT and\\u000a other pesticides

Barnett A. Rattner

2009-01-01

382

Toxicology of nitrous oxide  

Microsoft Academic Search

Since the first description of its anaesthetic effects by Horace Wells in 1844, nitrous oxide (N2O) or ‘laughing-gas’ was, for a long period, considered to be an inert gas. However, since Lassen, in 1956, published details of the occurrence of aplastic anaemia and septicaemia in patients after prolonged N2O-exposure, we know that there are toxicological effects.The majority of these secondary

Jessika Takács

2001-01-01

383

Toxicology of mycotoxins  

Microsoft Academic Search

\\u000a Humans are exposed to mycotoxins via ingestion, contact and inhalation. This must have occurred throughout human history and led to severe outbreaks. Potential\\u000a diseases range from akakabio-byo to stachybotryotoxicosis and cancer. The known molecular bases of toxicology run the gamut\\u000a of 23 compounds, from aflatoxins (AFs) to zearalenone, ochratoxin A and deoxynivalenol. Ergotism is one of the oldest recognized\\u000a mycotoxicosis,

Robert R. M. Paterson; Nelson Lima

384

Meloxicam: A toxicology overview  

Microsoft Academic Search

Meloxicam is a new potent non-steroidal anti-inflammatory drug (NSAID), which in animal tests exhibits potential antiarthritic\\u000a action and has a wider spectrum of anti-inflammatory activity than currently available NSAIDs. Toxicological testing of meloxicam\\u000a in animals suggests that acute oral overdosage is unlikely to cause severe toxicity in man. Compared with other NSAIDs, meloxicam\\u000a has a relatively weak effect on gastric

H. A. Lehmann; M. Baumeister; L. Lützen; J. Wiegleb

1996-01-01

385

Toxicological Benchmarks for Wildlife  

Microsoft Academic Search

Ecological risks of environmental contaminants are evaluated by using a two-tiered process. In the first tier, a screening assessment is performed where concentrations of contaminants in the environment are compared to no observed adverse effects level (NOAEL)-based toxicological benchmarks. These benchmarks represent concentrations of chemicals (i.e., concentrations presumed to be nonhazardous to the biota) in environmental media (water, sediment, soil,

B. E. Opresko; D. M. Suter

1993-01-01

386

Advances in Preclinical SPECT Instrumentation  

PubMed Central

Preclinical SPECT imaging of rodents is both in demand and very demanding. The need for high spatial resolution in combination with good sensitivity has given rise to considerable innovation in the areas of detectors, collimation, acquisition geometry, and image reconstruction. Some of the developments described herein are beginning to carry over into clinical imaging as well.

Peterson, Todd E.; Shokouhi, Sepideh

2012-01-01

387

Toxicological Benchmarks for Wildlife  

SciTech Connect

Ecological risks of environmental contaminants are evaluated by using a two-tiered process. In the first tier, a screening assessment is performed where concentrations of contaminants in the environment are compared to no observed adverse effects level (NOAEL)-based toxicological benchmarks. These benchmarks represent concentrations of chemicals (i.e., concentrations presumed to be nonhazardous to the biota) in environmental media (water, sediment, soil, food, etc.). While exceedance of these benchmarks does not indicate any particular level or type of risk, concentrations below the benchmarks should not result in significant effects. In practice, when contaminant concentrations in food or water resources are less than these toxicological benchmarks, the contaminants may be excluded from further consideration. However, if the concentration of a contaminant exceeds a benchmark, that contaminant should be retained as a contaminant of potential concern (COPC) and investigated further. The second tier in ecological risk assessment, the baseline ecological risk assessment, may use toxicological benchmarks as part of a weight-of-evidence approach (Suter 1993). Under this approach, based toxicological benchmarks are one of several lines of evidence used to support or refute the presence of ecological effects. Other sources of evidence include media toxicity tests, surveys of biota (abundance and diversity), measures of contaminant body burdens, and biomarkers. This report presents NOAEL- and lowest observed adverse effects level (LOAEL)-based toxicological benchmarks for assessment of effects of 85 chemicals on 9 representative mammalian wildlife species (short-tailed shrew, little brown bat, meadow vole, white-footed mouse, cottontail rabbit, mink, red fox, and whitetail deer) or 11 avian wildlife species (American robin, rough-winged swallow, American woodcock, wild turkey, belted kingfisher, great blue heron, barred owl, barn owl, Cooper's hawk, and red-tailed hawk, osprey) (scientific names for both the mammalian and avian species are presented in Appendix B). [In this document, NOAEL refers to both dose (mg contaminant per kg animal body weight per day) and concentration (mg contaminant per kg of food or L of drinking water)]. The 20 wildlife species were chosen because they are widely distributed and provide a representative range of body sizes and diets. The chemicals are some of those that occur at U.S. Department of Energy (DOE) waste sites. The NOAEL-based benchmarks presented in this report represent values believed to be nonhazardous for the listed wildlife species; LOAEL-based benchmarks represent threshold levels at which adverse effects are likely to become evident. These benchmarks consider contaminant exposure through oral ingestion of contaminated media only. Exposure through inhalation and/or direct dermal exposure are not considered in this report.

Sample, B.E. Opresko, D.M. Suter, G.W.

1993-01-01

388

A 90-day toxicology study of high-amylose transgenic rice grain in Sprague-Dawley rats.  

PubMed

A transgenic rice line (TRS) with high amylose level has been developed by antisense RNA inhibition of starch branching enzymes. Compositional analysis of TRS demonstrated that the content of resistant starch (RS) was significantly higher compared to conventional non-transgenic rice. High level of RS is an important raw material in food industry and has various physiological effects for human health. In order to provide the reliable theory basis for field release of TRS rice, we evaluated the potential health effects of long-term consumption of the TRS. The 90-day toxicology feeding experiment was conducted in Sprague-Dawley rats fed with diets containing 70% of either TRS rice flour, its near-isogenic rice flour or the control diet. The clinical performance variables (body weight, body weight gain and food consumption) were measured and pathological responses (hematological parameters and serum chemistry at the midterm and the completion of the experiment, urinalysis profile and serum sex hormone response at the completion of the experiment) were performed. Besides, clinical signs, relative organ weights and microscopic observations were also compared between TRS group and its near-isogenic rice group. The combined data indicates that high-amylose TRS grain is as safe as the conventional non-transgenic rice for rat consumption. PMID:21967780

Zhou, Xing Hua; Dong, Ying; Xiao, Xiang; Wang, Yun; Xu, Yong; Xu, Bin; Shi, Wei Dong; Zhang, Yi; Zhu, Li Jia; Liu, Qiao Quan

2011-09-24

389

Lost in translation: preclinical studies on 3,4-methylenedioxymethamphetamine provide information on mechanisms of action, but do not allow accurate prediction of adverse events in humans  

PubMed Central

3,4-Methylenedioxymethamphetamine (MDMA) induces both acute adverse effects and long-term neurotoxic loss of brain 5-HT neurones in laboratory animals. However, when choosing doses, most preclinical studies have paid little attention to the pharmacokinetics of the drug in humans or animals. The recreational use of MDMA and current clinical investigations of the drug for therapeutic purposes demand better translational pharmacology to allow accurate risk assessment of its ability to induce adverse events. Recent pharmacokinetic studies on MDMA in animals and humans are reviewed and indicate that the risks following MDMA ingestion should be re-evaluated. Acute behavioural and body temperature changes result from rapid MDMA-induced monoamine release, whereas long-term neurotoxicity is primarily caused by metabolites of the drug. Therefore acute physiological changes in humans are fairly accurately mimicked in animals by appropriate dosing, although allometric dosing calculations have little value. Long-term changes require MDMA to be metabolized in a similar manner in experimental animals and humans. However, the rate of metabolism of MDMA and its major metabolites is slower in humans than rats or monkeys, potentially allowing endogenous neuroprotective mechanisms to function in a species specific manner. Furthermore acute hyperthermia in humans probably limits the chance of recreational users ingesting sufficient MDMA to produce neurotoxicity, unlike in the rat. MDMA also inhibits the major enzyme responsible for its metabolism in humans thereby also assisting in preventing neurotoxicity. These observations question whether MDMA alone produces long-term 5-HT neurotoxicity in human brain, although when taken in combination with other recreational drugs it may induce neurotoxicity. LINKED ARTICLES This article is commented on by Parrott, pp. 1518–1520 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2012.01941.x and to view the the rebuttal by the authors (Green et al., pp. 1521–1522 of this issue) visit http://dx.doi.org/10.1111/j.1476-5381.2012.01940.x

Green, AR; King, MV; Shortall, SE; Fone, KCF

2012-01-01

390

Toxicology Studies on Lewisite and Sulfur Mustard Agents: Two-Generation Reproduction Study of Lewisite in Rats Final Report  

SciTech Connect

Occupational health standards have not been established for Lewisite [bis(2-chlorethyl)arsine], a potent toxic vesicant which reacts with the sulfhydryl groups of proteins through its arsenic group. The purposes of this study were to determine the reproductive consequences and dose~response of continuing Lewisite exposure of parental males and females and their offspring in a 42-week two-generation study. Solutions of Lewisite were prepared for administration by diluting the neat agent with sesame oil. Rats were administered Lewisite (0, 0.10, 0.25 or 0.60 mg/kg/day for 5 days a week) via intragastric intubation prior to mating, during mating and after mating until the birth of their offspring. The dams continued to receive Lewisite during lactation. At weaning, male and female offspring of each group were selected to continue on the study; rece1v1ng Lewisite during adolescence, mating and throughout gestation. Again, the dams continued to receive Lewisite until weaning of the offspring. Lewisite had no adverse effect on reproduction performance, fertility or reproductive organ weights of male or female rats through two consecutive generations. No adverse effect to offspring were attributed to Lewisite exposure. Minor changes in growth was the only maternal effect observed. Lewisite exposure of parental rats caused no gross or microscopic lesions in testes, epididymis, prostrate, seminal vesicles, ovaries, uterus or vagina. Severe inflammation of the lung was observed at necropsy in cases in which Lewisite gained access to the respiratory system from accidental dosing or reflux and aspiration; this usually caused early death of the animal. The NOEL for reproductive effects in this study was greater than 0.60 mg/kg/day.

Sasser, L. B.; Cushing, J. A.; Kalkwarf, D. R.; Mellick, P. W.; Buschbom, R. L.

1989-07-15

391

Transgenic Fish as Models in Environmental Toxicology  

Microsoft Academic Search

Historically, fish have played significant roles in assessing potential risks associated with exposure to chemical con- tamination in aquatic environments. Considering the contri- butions of transgenic rodent models to biomedicine, it is reasoned that the development of transgenic fish could enhance the role of fish in environmental toxicology. Application of transgenic fish in environmental studies remains at an early stage,

Richard N. Winn

392

Research Models in Developmental Behavioral Toxicology.  

ERIC Educational Resources Information Center

Developmental models currently used by child behavioral toxicologists and teratologists are inadequate to address current issues in these fields. Both child behavioral teratology and toxicology scientifically study the impact of exposure to toxic agents on behavior development: teratology focuses on prenatal exposure and postnatal behavior…

Dietrich, Kim N.; Pearson, Douglas T.

393

Research Models in Developmental Behavioral Toxicology.  

ERIC Educational Resources Information Center

|Developmental models currently used by child behavioral toxicologists and teratologists are inadequate to address current issues in these fields. Both child behavioral teratology and toxicology scientifically study the impact of exposure to toxic agents on behavior development: teratology focuses on prenatal exposure and postnatal behavior…

Dietrich, Kim N.; Pearson, Douglas T.

394

Chronic Mammalian Toxicological Effects of LAP Wastewater.  

National Technical Information Service (NTIS)

The objective of these studies was to provide a comprehensive definition of the long-term toxicological effects of LAP wastewater (TNT/RDX in a ratio of 1.6 to 1) on Fischer-344 rats with respect to possible lesions at the biochemical and cellular levels....

J. M. Brown R. J. Spanggord T. A. Jorgenson

1983-01-01

395

TOXICOLOGICAL EVALUATION OF SELECTED CHLORINATED PHENOLS  

EPA Science Inventory

Toxicology studies were conducted with the mono-, di-, and pentachlorophenols (CP). Chlorophenols (except PC) demonstrate a relatively low order of toxicity. The order of toxicity in mice and rats (most to least) is: PCP > tetra CPs > mono CPs > tri CPs > di CPs. Short-term (14 d...

396

Toxicological Profile for Ethion (Update), 2000.  

National Technical Information Service (NTIS)

Toxicological Profiles are a unique compilation of toxicological information on a given hazardous substance. Each profile reflects a comprehensive and extensive evaluation, summary, and interpretation of available toxicologic and epidemiologic information...

2000-01-01

397

Toxicological Profile for Methylene Chloride (Update), 2000.  

National Technical Information Service (NTIS)

Toxicological Profiles are a unique compilation of toxicological information on a given hazardous substance. Each profile reflects a comprehensive and extensive evaluation, summary, and interpretation of available toxicologic and epidemiologic information...

2000-01-01

398

Toxicological Profile for Manganese and Compounds.  

National Technical Information Service (NTIS)

The ATSDR Toxicological Profile is intended to characterize succinctly the toxicological and health effects information for manganese compounds. It identifies and reviews the key literature that describes manganese compounds' toxicological properties. Oth...

1992-01-01

399

Toxicology Studies on Lewisite and Sulfur Mustard Agents: Modified Dominant Lethal Study of Sulfur Mustard in Rats Final Report  

SciTech Connect

Occupational health standards have not been established for sulfur mustard (HD) [bis{2-chloroethyl)-sulfide) ' a strong alkylating agent with known mutagenic properties. Little, however, is known about the mutagenic activity of HD in mammalian species and data regarding the dominant lethal effects of HD are ambiguous. The purpose of this study was to determine the dominant lethal effect in male and female rats orally exposed to HD. The study was conducted in two phases; a female dominant lethal phase and a male dominant lethal phase. Sprague-Dawley rats of each sex were administered 0.08, 0.20, or 0.50 mg/kg HD in sesame oil 5 days/week for 10 weeks. For the female phase, treated or untreated males were mated with treated females and their fetuses were evaluated at approximately 14 days after copulation. For the male dominant lethal phase, treated males cohabited with untreated femal (during 5 days of each week for 10 weeks) and females were sacrificed for fetal evaluation 14 days after the midweek of cohabitation during each of the 10 weeks. The appearance and behavior of the rats were unremarkable throughout the experiment and there were no treatment-related deaths. Growth rates were reduced in both female and male rats treated with 0.50 mg/kg HD. Indicators of reproductive performance did not demonstrate significant female dominant lethal effects, although significant male dominant lethal effects were observed at 2 and 3 week post-exposure. These effects included increases of early fetal resorptions and preimplantation losses and decreases of total live embryo implants. These effects were most consistently observed at a dose of 0.50 mg/kg, but frequently occurred at the lower doses. Although no treatment-related effects on male reproductive organ weights or sperm motility were found, a significant increase in the percentage of abnormal sperm was detected in males exposed to 0. 50 mg/kg HD. The timing of these effects is consistent with an effect during the postmeiotic stages of spermatogenesis, possibly involving the generally sensitive spermatids.

Sasser, L. B.; Cushing, J. A.; Kalkwarf, D. R.; Buschbom, R. L.

1989-05-01

400

Synthetic toxicology: where engineering meets biology and toxicology.  

PubMed

This article examines the implications of synthetic biology (SB) for toxicological sciences. Starting with a working definition of SB, we describe its current subfields, namely, DNA synthesis, the engineering of DNA-based biological circuits, minimal genome research, attempts to construct protocells and synthetic cells, and efforts to diversify the biochemistry of life through xenobiology. Based on the most important techniques, tools, and expected applications in SB, we describe the ramifications of SB for toxicology under the label of synthetic toxicology. We differentiate between cases where SB offers opportunities for toxicology and where SB poses challenges for toxicology. Among the opportunities, we identified the assistance of SB to construct novel toxicity testing platforms, define new toxicity-pathway assays, explore the potential of SB to improve in vivo biotransformation of toxins, present novel biosensors developed by SB for environmental toxicology, discuss cell-free protein synthesis of toxins, reflect on the contribution to toxic use reduction, and the democratization of toxicology through do-it-yourself biology. Among the identified challenges for toxicology, we identify synthetic toxins and novel xenobiotics, biosecurity and dual-use considerations, the potential bridging of toxic substances and infectious agents, and do-it-yourself toxin production. PMID:21068213

Schmidt, Markus; Pei, Lei

2010-11-10

401

Genetic Modification of Risk Assessment Based on Staging of Preclinical Type 1 Diabetes in Siblings of Affected Children  

Microsoft Academic Search

We set out to study the association between human leukocyte antigen-defined genetic disease susceptibility and the stage of preclinical type 1 diabetes and whether genetic predisposi- tion affects the natural course of preclinical diabetes in ini- tially nondiabetic siblings of affected children. A total of 701 initially unaffected siblings were graded into four stages of preclinical type 1 diabetes based

S. MRENA; K. SAVOLA; P. KULMALA; H. REIJONEN; J. ILONEN; H. K. ÅKERBLOM; M. KNIP

2010-01-01

402

Reprint Library for Toxicology Data Bank  

ERIC Educational Resources Information Center

The Industrial Toxicology Research Center, Lucknow, India, maintains a register of toxicology and provides its research workers with current information mainly through its collection of reprints. (Author)

Agarwal, S. N.; Khan, R. R.

1975-01-01

403

Reprint Library for Toxicology Data Bank  

ERIC Educational Resources Information Center

|The Industrial Toxicology Research Center, Lucknow, India, maintains a register of toxicology and provides its research workers with current information mainly through its collection of reprints. (Author)|

Agarwal, S. N.; Khan, R. R.

1975-01-01

404

Global Recognition of Qualified Toxicologic Pathologists: Credential Review as a Potential Route for Recognizing the Proficiency of Pathologists Involved in Regulatory-type Nonclinical Studies*  

PubMed Central

Recent international summits of the International Federation of Societies of Toxicologic Pathologists (IFSTP) have debated the desirability and potential means by which the proficiency of an individual toxicologic pathologist might be recognized and communicated throughout the world. The present document describes the advantages and disadvantages of implementing such a global recognition system by any means, and provides a proposal whereby recognition might be accorded via rigorous credential review of a practitioner’s education and experience.

Ettlin, Robert A.; Bolon, Brad; Pyrah, Ian; Konishi, Yoichi; Black, Hugh E.

2009-01-01

405

Pharmacogenetics and forensic toxicology.  

PubMed

Large inter-individual variability in drug response and toxicity, as well as in drug concentrations after application of the same dosage, can be of genetic, physiological, pathophysiological, or environmental origin. Absorption, distribution and metabolism of a drug and interactions with its target often are determined by genetic differences. Pharmacokinetic and pharmacodynamic variations can appear at the level of drug metabolizing enzymes (e.g., the cytochrome P450 system), drug transporters, drug targets or other biomarker genes. Pharmacogenetics or toxicogenetics can therefore be relevant in forensic toxicology. This review presents relevant aspects together with some examples from daily routines. PMID:20828952

Musshoff, Frank; Stamer, Ulrike M; Madea, Burkhard

2010-09-09

406

Toxicology: Old Art, New Science.  

ERIC Educational Resources Information Center

|Examines the need for a science of toxicology and training at both the undergraduate and graduate levels in response to legislation controlling drugs, food additives and toxic substances in the work environment, and concern about effects on man. Stresses need for putting toxicology on a scientific base with adequate funding. (JM)|

Timbrell, John A.

1983-01-01

407

Historical perspectives on cadmium toxicology  

SciTech Connect

The first health effects of cadmium (Cd) were reported already in 1858. Respiratory and gastrointestinal symptoms occurred among persons using Cd-containing polishing agent. The first experimental toxicological studies are from 1919. Bone effects and proteinuria in humans were reported in the 1940's. After World War II, a bone disease with fractures and severe pain, the itai-itai disease, a form of Cd-induced renal osteomalacia, was identified in Japan. Subsequently, the toxicokinetics and toxicodynamics of Cd were described including its binding to the protein metallothionein. International warnings of health risks from Cd-pollution were issued in the 1970's. Reproductive and carcinogenic effects were studied at an early stage, but a quantitative assessment of these effects in humans is still subject to considerable uncertainty. The World Health Organization in its International Program on Chemical Safety, WHO/IPCS (1992) (Cadmium. Environmental Health Criteria Document 134, IPCS. WHO, Geneva, 1-280.) identified renal dysfunction as the critical effect and a crude quantitative evaluation was presented. In the 1990's and 2000 several epidemiological studies have reported adverse health effects, sometimes at low environmental exposures to Cd, in population groups in Japan, China, Europe and USA (reviewed in other contributions to the present volume). The early identification of an important role of metallothionein in cadmium toxicology formed the basis for recent studies using biomarkers of susceptibility to development of Cd-related renal dysfunction such as gene expression of metallothionein in peripheral lymphocytes and autoantibodies against metallothionein in blood plasma. Findings in these studies indicate that very low exposure levels to cadmium may give rise to renal dysfunction among sensitive subgroups of human populations such as persons with diabetes.

Nordberg, Gunnar F. [Environmental Medicine, Department of Public Health and Clinical Medicine, Umea University, SE-90187 Umea (Sweden)], E-mail: gunnar.nordberg@envmed.umu.se

2009-08-01

408

Meal-feeding rodents and toxicology research.  

PubMed

Most laboratory rodents used for toxicology studies are fed ad libitum, with unlimited access to food. As a result, ad libitum-fed rodents tend to overeat. Research demonstrates that ad libitum-fed rodents are physiologically and metabolically different from rodents fed controlled amounts of food at scheduled times (meal-fed). Ad libitum-fed rodents can develop hypertriglyceridemia, hypercholesterolemia, diet-induced obesity, nephropathy, cardiomyopathy, and pituitary, pancreatic, adrenal, and thyroid tumors, conditions likely to affect the results of toxicology research studies. In contrast, meal-feeding synchronizes biological rhythms and leads to a longer life span, lower body weight, lower body temperature, hypertrophy of the small intestine, and synchronization of hepatic and digestive enzymes. The circadian rhythms present in nearly all living organisms are entrained by light intensity and food intake, and peripheral clocks in all organs of the body, especially the GI tract and liver, are particularly sensitive to food intake. Feeding schedule has been demonstrated to alter the toxicity and metabolism of drugs including sodium valproate, chloral hydrate, acetaminophen, gentamicin, and methotrexate. Feeding schedule alters the expression of genes that code for Phase I, II, and III proteins, thereby altering the rate and amplitude of drug disposition. Rhythms of plasma insulin and glucagon that fluctuate with food ingestion are also altered by feeding schedule; ad libitum feeding promotes hyperinsulinemia which is a precursor for developing diabetes. The emerging field of chronopharmacology, the interaction of biological rhythms and drugs, will lead to optimizing the design and delivery of drugs in a manner that matches biological rhythms, but it is wise for toxicology researchers to consider feeding schedule when designing these experiments. It has been 10 years since the Society for Toxicologic Pathology voiced its position that feeding schedule is an important variable that should be controlled in toxicology experiments, and research continues to underscore this position. PMID:22642213

Carey, Gale B; Merrill, Lisa C

2012-06-13

409

Substitute Chemical Program - The First Year of Proceedings of a Symposium. Volume II. Toxicological Methods and Genetic Effects Workshop.  

National Technical Information Service (NTIS)

Partial contents: Toxicological methods and genetic effects research progress session introduction; Inhalation toxicology; Studies on toxicity to mammals of small particle aerosols of nuclear polyhedrosis virus (NPV) pesticides; Metabolism of pesticides; ...

1976-01-01

410

Toxicology of chemical mixtures: Experimental approaches, underlying concepts, and some results  

SciTech Connect

The toxicology of chemical mixtures will be the toxicology of the 1990s and beyond. While this branch of toxicology most closely reflects the actual human exposure situation, as yet there is no standard protocol or consensus methodology for investigating the toxicology of mixtures. Thus, in this emerging science, experimentation is required just to develop a broadly applicable evaluation system. Several examples are discussed to illustrate the different experimental designs and the concepts behind each. These include the health effects studies of Love Canal soil samples, the Lake Ontario Coho salmon, the water samples repurified from secondary sewage in the city of Denver Potable Water Reuse Demonstration Plant, and the National Toxicology Program (NTP) effort on a mixture of 25 frequently detected groundwater contaminants derived from hazardous waste disposal sites. In the last instance, an extensive research program has been ongoing for the last two years at the NTP, encompassing general toxicology, immunotoxicology, developmental and reproductive toxicology, biochemical toxicology, myelotoxicology, genetic toxicology, neurobehavioral toxicology, and hepato- and renal toxicology.

Yang, R.S.; Long, H.L.; Boorman, G.A.

1990-07-01

411

Toxicology of chemical mixtures: experimental approaches, underlying concepts, and some results.  

PubMed

The toxicology of chemical mixtures will be the toxicology of the 1990s and beyond. While this branch of toxicology most closely reflects the actual human exposure situation, there is yet no standard protocol or consensus methodology for investigating the toxicology of mixtures. Thus, in this emerging science, experimentation is required just to develop a broadly applicable evaluation system. Several examples are discussed to illustrate the different experimental designs and the concepts behind each. These include the health effects studies of Love Canal soil samples, the Lake Ontario Coho salmon, the water samples repurified from secondary sewage in the city of Denver Potable Water Reuse Demonstration Plant, and the National Toxicology Program (NTP) effort on a mixture of 25 frequently detected groundwater contaminants derived from hazardous waste disposal sites. In the last instance, an extensive research program has been ongoing for the last 2 years at the NTP, encompassing general toxicology, immunotoxicology, developmental and reproductive toxicology, biochemical toxicology, myelotoxicology, genetic toxicology, neurobehavioral toxicology, and hepato- and renal toxicology. PMID:2690403

Yang, R S; Hong, H L; Boorman, G A

1989-12-01

412

Textile dye degradation by bacterial consortium and subsequent toxicological analysis of dye and dye metabolites using cytotoxicity, genotoxicity and oxidative stress studies.  

PubMed

The present study aims to evaluate Red HE3B degrading potential of developed microbial consortium SDS using two bacterial cultures viz. Providencia sp. SDS (PS) and Pseudomonas aeuroginosa strain BCH (PA) originally isolated from dye contaminated soil. Consortium was found to be much faster for decolorization and degradation of Red HE3B compared to the individual bacterial strain. The intensive metabolic activity of these strains led to 100% decolorization of Red HE3B (50 mg l(-1)) with in 1h. Significant induction of various dye decolorizing enzymes viz. veratryl alcohol oxidase, laccase, azoreductase and DCIP reductase compared to control, point out towards their involvement in overall decolorization and degradation process. Analytical studies like HPLC, FTIR and GC-MS were used to scrutinize the biodegradation process. Toxicological studies before and after microbial treatment was studied with respect to cytotoxicity, genotoxicity, oxidative stress, antioxidant enzyme status, protein oxidation and lipid peroxidation analysis using root cells of Allium cepa. Toxicity analysis with A. cepa signifies that dye Red HE3B exerts oxidative stress and subsequently toxic effect on the root cells where as biodegradation metabolites of the dye are relatively less toxic in nature. Phytotoxicity studies also indicated that microbial treatment favors detoxification of Red HE3B. PMID:21144656

Phugare, Swapnil S; Kalyani, Dayanand C; Patil, Asmita V; Jadhav, Jyoti P

2010-11-19

413

High Hematocrit Resulting from Administration of Erythropoiesis-stimulating Agents Is Not Fully Predictive of Mortality or Toxicities in Preclinical Species.  

PubMed

We conducted a retrospective analysis of publicly available preclinical toxicology studies with erythropoiesis-stimulating agents (ESAs) to examine common adverse events in rats, Beagle dogs, and cynomolgus monkeys. Mortality and/or thrombotic events were reported sporadically in a subset of studies and attributed to the high hematocrit (HCT) achieved in the animals. However, similarly high HCT was achieved in both high-dose and low-dose groups, but there were no reported adverse events in the low-dose group suggesting HCT was not the sole contributing factor leading to toxicity. Our analysis indicated that increased dose, dose frequency, and dosing duration in addition to high HCT contributed to mortality and thrombosis. To further evaluate this relationship, the incidence of toxicities was compared in rats administered an experimental hyperglycosylated analog of recombinant human erythropoietin (AMG 114) at varying dosing schedules in 1-month toxicity studies. The incidence of mortality and thrombotic events increased in higher dose groups and when dosed more frequently, despite a similarly high HCT in all animals. The results from the investigative study and retrospective analysis demonstrate that ESA-related toxicities in preclinical species are associated with dose level, dose frequency, and dosing duration, and not solely dependent upon a high HCT. PMID:23674390

Andrews, Dina A; Pyrah, Ian T G; Boren, Babette M; Tannehill-Gregg, Sarah H; Lightfoot-Dunn, Ruth M

2013-05-14