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1

Preclinical Toxicology of New Drugs.  

National Technical Information Service (NTIS)

Preclinical toxicology studies of WR238605, Succinate and Pyridostigmine Bromide are being performed to assist the U.S. Army Medical R&D Command (USAMRDC) in its decision of whether or not to allow widespread clinical use of these agents. Subacute (28 day...

J. G. Page

1986-01-01

2

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

3

Preclinical Toxicology Studies of New Drugs and Vaccines.  

National Technical Information Service (NTIS)

During the reporting period, Thirteen Week Oral Toxicity Studies of WR6026 with a Thirteen Week Recovery Period in dogs and rats, In Vitro Mutagenicity Tests of HI-6 Dichloride and an Acute Oral and intraperitoneal Toxicity Study of WR242511 and WR269410 ...

B. S. Levine

1993-01-01

4

Preclinical toxicology and biodistribution studies of recombinant adeno-associated virus 1 human acid ?-glucosidase.  

PubMed

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

5

Use of mixed-effect models and tolerance limits to evaluate control cynomolgus monkey body weight change and variability during preclinical toxicology studies  

Microsoft Academic Search

Cynomolgus monkeys are an important and widely used species in preclinical toxicology studies. During the in-life phase of study, body weight effects may be indicative of toxicity; however, trends in body weight and body weight variability are often difficult to interpret due to small sample size and\\/or inter- and intra-animal variability. The present analysis utilizes mixed-effect modelling, which incorporates random

Ronnie L. Yeager; Dong Zhao; Yan Lan; Duane Poage; C. Thomas Lin; Michael D. DuVall

2011-01-01

6

Metabolomics in Toxicology and Preclinical Research  

PubMed Central

Summary Metabolomics, the comprehensive analysis of metabolites in a biological system, provides detailed information about the biochemical/physiological status of a biological system, and about the changes caused by chemicals. Metabolomics analysis is used in many fields, ranging from the analysis of the physiological status of genetically modified organisms in safety science to the evaluation of human health conditions. In toxicology, metabolomics is the -omics discipline that is most closely related to classical knowledge of disturbed biochemical pathways. It allows rapid identification of the potential targets of a hazardous compound. It can give information on target organs and often can help to improve our understanding regarding the mode-of-action of a given compound. Such insights aid the discovery of biomarkers that either indicate pathophysiological conditions or help the monitoring of the efficacy of drug therapies. The first toxicological applications of metabolomics were for mechanistic research, but different ways to use the technology in a regulatory context are being explored. Ideally, further progress in that direction will position the metabolomics approach to address the challenges of toxicology of the 21st century. To address these issues, scientists from academia, industry, and regulatory bodies came together in a workshop to discuss the current status of applied metabolomics and its potential in the safety assessment of compounds. We report here on the conclusions of three working groups addressing questions regarding 1) metabolomics for in vitro studies 2) the appropriate use of metabolomics in systems toxicology, and 3) use of metabolomics in a regulatory context.

Ramirez, Tzutzuy; Daneshian, Mardas; Kamp, Hennicke; Bois, Frederic Y.; Clench, Malcolm R.; Coen, Muireann; Donley, Beth; Fischer, Steven M.; Ekman, Drew R.; Fabian, Eric; Guillou, Claude; Heuer, Joachim; Hogberg, Helena T.; Jungnickel, Harald; Keun, Hector C.; Krennrich, Gerhard; Krupp, Eckart; Luch, Andreas; Noor, Fozia; Peter, Erik; Riefke, Bjoern; Seymour, Mark; Skinner, Nigel; Smirnova, Lena; Verheij, Elwin; Wagner, Silvia; Hartung, Thomas; van Ravenzwaay, Bennard; Leist, Marcel

2013-01-01

7

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

8

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

9

Preclinical toxicology studies with the new dopamine agonist pergolide. Acute, subchronic, and chronic evaluations.  

PubMed

Pergolide (LY127809, CAS 66104-23-2), a dopamine agonist for the treatment of Parkinson's disease, was evaluated for toxicity in acute, subchronic, and chronic studies. Acute toxicity tests using oral, intravenous and intraperitoneal routes were conducted in rats, mice, rabbits, and dogs. The acute oral median lethal doses (MLD) ranged from 8.4 to 33.6 mg/kg in Wistar and Fischer 344 rats, and from 54.0 to 87.2 mg/kg in ICR mice. Oral doses of 20 and 25 mg/kg produced no mortality in rabbits or dogs, respectively. The MLD by the iv route ranged from 0.59 to 0.87 mg/kg for Fischer 344 rats and from 11.6 to 37.1 mg/kg for ICR mice. The predominant signs of toxicity in the acute studies included hyperactivity, poor grooming, ptosis, aggressive behavior, increased gnawing activity, tremors, convulsions, and emesis. In the subchronic and chronic studies, Fischer 344 rats, B6C3F1 mice, and beagle dogs were administered pergolide either by gavage or in the diet for up to 1 year. Daily doses in these studies ranged up to 20 mg/kg for rats, 45 mg/kg for mice, and 5 mg/kg for dogs. The predominant treatment-related effects seen in these studies were attributable to the pharmacologic activity of pergolide. These consisted primarily of CNS-mediated clinical signs in rats and dogs, weight loss or decreased weight gain, emesis in dogs, and inhibition of lysis of corpora lutea with a corresponding increase in the weight of the uterus and ovaries. Pergolide treatment was not associated with any specific target organ toxicity.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8192691

Francis, P C; Carlson, K H; Owen, N V; Adams, E R

1994-03-01

10

Preclinical toxicology studies with acyclovir: carcinogenicity bioassays and chronic toxicity tests.  

PubMed

Acyclovir (ACV), a nucleoside analog that is a new herpes-specific antiviral drug, was given by gavage at 50, 150 and 450 mg/kg/day to Sprague Dawley rats and Swiss mice for most of their lifetime to assess chronic toxicity and carcinogenicity. Treatment with ACV did not shorten the lifespan of either rats or mice. In fact, female mice given 150 and 450 mg/kg/day had significantly longer mean durations of survival than control female mice when analyzed by the life table technique. There were no signs of toxicosis produced by chronic exposure to ACV in either the rats or mice, and there was no drug-related increase in neoplasms in either species. Four groups of Beagle dogs were initially given daily oral doses of 15, 45 or 150 mg/kg ACV in a 1 year chronic toxicity study. Dogs treated at 150 mg/kg/day vomited, had diarrhea, consumed less feed and lost weight within 2 weeks. Dogs treated at 45 mg/kg/day also had minimal signs of gastrointestinal toxicosis. These dose levels were then decreased to 60 and 30 mg/kg/day for the rest of the one year test period. With the exception of occasional and inconsistent emesis and diarrhea, the 60 mg/kg/day dose level was well tolerated. Some mid and high dose dogs had sore paws due to erosion of footpads and cracking, splitting and loosening of the nails first becoming evident during the 13th week of the study.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6662300

Tucker, W E; Krasny, H C; de Miranda, P; Goldenthal, E I; Elion, G B; Hajian, G; Szczech, G M

1983-01-01

11

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

12

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

2012-01-01

13

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

PubMed Central

1263W94 is a novel benzimidazole compound being developed for treatment of human cytomegalovirus infection. 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, and monocytes at higher doses in female rats. 1263W94 was not genotoxic in the Ames or micronucleus assays. In the mouse lymphoma assay, 1263W94 was mutagenic in the absence of the rat liver S-9 metabolic activation system, with equivocal results in the presence of the S-9 mix. Mean oral bioavailability of 1263W94 was >90% in rats and ?50% in monkeys. Clearance in rats and monkeys was primarily by biliary secretion, with evidence of enterohepatic recirculation. In 1-month studies in rats and monkeys, mean peak concentrations and exposures to 1263W94 increased in near proportion to dose. Metabolism of 1263W94 to its primary metabolite, an N-dealkylated analog, appeared to be mediated via the isozyme CYP3A4 in humans. 1263W94 was primarily distributed in the gastrointestinal tract of rats but did not cross the blood-brain barrier. In monkeys, 1263W94 levels in the brain, cerebrospinal fluid, and vitreous humor ranged from 4 to 20%, 1 to 2%, and <1%, of corresponding concentrations in plasma, respectively. The high level of binding by 1263W94 to human plasma proteins (primarily albumin) was readily reversible, with less protein binding seen in the monkey, rat, and mouse. Results of these studies demonstrate a favorable safety profile for 1263W94.

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

2002-01-01

14

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.

15

NSC-121 210 Dehydroepiandrosterone Mustard: Preclinical Toxicological Evaluation in Dogs.  

National Technical Information Service (NTIS)

Androst-5-en-17-one, 3 beta-hydroxy-, (p-(bis (2-chloroethyl) amino) phenyl)-acetate; (Dehydroepiandrosterone mustard) was submitted to a p.o. preclinical pharmacological evaluation in 16 dogs. Treatments included 14 oral daily consecutive doses of 21.4 t...

U. H. Schaeppi R. W. Fleischman I. A. Heyman H. Rosenkrantz V. Ilievski

1972-01-01

16

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

2011-01-01

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 Central

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.

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

2010-01-01

18

Toxicologic studies of SRC materials  

SciTech Connect

Investigations on the toxicity of SRC materials are reported. Toxicological studies include: microbial mutageneis (Ames test); in vitro mammalian cell toxicity and transformation assays; epidermal carcinogenesis (skin painting); acute and subchronic oral toxicity; developmental toxicity; dominant lethal assays; inhalation toxicity; and dosimetry and metabolism. The materials tested include: SRC-I process solvent, wash solvent, and light oil; SRC-II heavy distillate, middle distillate, and light distillate; shale oil; crude petroleum; and pure carcinogens. (DC)

Mahlum, D.D.; Pelroy, R.A.; Drucker, H.; Wilson, B.W.; Massey, M.J.; Schmalzer, D.K.

1980-02-01

19

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

20

Love Canal: environmental and toxicological studies  

Microsoft Academic Search

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

1981-01-01

21

Demands on scientific studies in clinical toxicology  

Microsoft Academic Search

Scientific case studies in clinical toxicology on single cases or series of similar cases should document sufficient information on the clinical methodology and observations, the medical laboratory methodology and results, the toxicological analyses methodology and results, the source of used reference values for drug\\/poison concentrations and kinetics with critical discussion of such values, a description and discussion of the toxicodynamic,

Hans H. Maurer

2007-01-01

22

Respiratory Toxicology Group: Inhalation Studies  

MedlinePLUS

... NTP Laboratory. He received his Ph.D. in Pharmacology and Toxicology from the University of Kansas in ... completed his postdoctoral work in the Department of Pharmacology and Medicine at Duke University Medical Center. He ...

23

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

24

Preclinical Studies of Raloxifene and Related Compounds  

Microsoft Academic Search

\\u000a The development of raloxifene (also know as keoxifene) for clinical use was based on a series of preclinical studies that\\u000a demonstrated it has a highly desirable tissue-specific activity. Results indicated that the therapeutic effects of raloxifene\\u000a (LY138481 HCl; LY156758) mimicked some of those of estrogen in ovariectomized animals by reducing bone loss and lowering serum\\u000a cholesterol levels. Conversely, in mammary

Robin Fuchs-Young

25

Ibandronate: pharmacology and preclinical studies.  

PubMed

Over the past three decades, changes to the chemical structures of the bisphosphonates have resulted in progressive improvements in their antiresorptive potencies. Ibandronate is a potent, nitrogen-containing bisphosphonate that possesses a tertiary nitrogen group on its R2 side chain and a hydroxyl group on its R1 side chain, which together confer one of the highest antiresorptive potencies of all bisphosphonates. In common with other nitrogen-containing bisphosphonates, ibandronate is a strong inhibitor of farnesyl pyrophosphate synthase, which probably accounts for its major effects on osteoclast activity. In addition, it binds strongly to hydroxyapatite. The pharmacological efficacy and safety of various continuous and intermittent regimens of ibandronate have been extensively investigated in experimental models of osteoporosis in several animal species, including rats, dogs, and monkeys. In ovariectomized (OVX) rats, intermittent (dosing interval 2, 4, and 6 weeks) and continuous ibandronate regimens provided equivalent results per total dose irrespective of the dosing regimen. Similar results were obtained in OVX dogs and monkeys. High doses of ibandronate many times those used therapeutically were well tolerated and did not impair bone quality or mineralization in rats. Moreover, bone mass, architecture, and strength were maintained or improved, and bone healing was not adversely affected in animal models, regardless of whether ibandronate was administered intermittently or daily. The findings from all these studies demonstrate the efficacy and safety of intermittent ibandronate regimens and support the development of such regimens for the clinical management of postmenopausal osteoporosis. PMID:16531132

Russell, R G G

2006-04-01

26

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

27

Immunologic and toxicologic study of disaccharide tripeptide glycerol dipalmitoyl: a new lipophilic immunomodulator.  

PubMed

A new lipophilic immunomodulator, disaccharide tripeptide glycerol dipalmitoyl (DTP-GDP), has been synthesized and evaluated for its immunologic activity and toxicology. DTP-GDP alone or in liposomes is more effective as an adjuvant and in activating macrophages compared with muramyldipeptide (MDP). Preclinical studies demonstrate no evidence of toxicity, including vasculitis. DTP-GDP in liposomes has shown antitumor activity in phase I clinical trials. PMID:2185794

Vosika, G J; Cornelius, D A; Bennek, J A; Sadlik, J R; Gilbert, C W

1990-03-01

28

Comparative Inhalation Toxicology of Selected Materials. Phase 3 Studies.  

National Technical Information Service (NTIS)

The U.S. Army Biomedical Research and Development Laboratory (USABRDL) sponsored the Lovelace Inhalation Toxicology Research Institute (LITRI) to study the inhalation toxicity of respirable aerosols of powdered Cu-Zn alloy (Cu-Zn). Toxicological informati...

A. F. Eidson D. E. Bice D. G. Burt E. G. Damon M. B. Snipes

1988-01-01

29

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

30

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

31

Preclinical toxicology studies with acyclovir: ophthalmic and cutaneous tests.  

PubMed

Topical formulations of acyclovir (ACV) were tested in animals to define potential for tissue irritation and systemic toxicity. Acyclovir ointments (5 and 10% concentrations in polyethylene glycol vehicle) produced no sign of dermal irritation or systemic toxicity when applied to shaved abraded and intact skin of guinea pigs for 24 consecutive days. Solutions (0.9% normal saline vehicle) of ACV did not sensitize guinea pigs when 10 sensitizing doses and a challenge dose were injected intradermally. Petrolatum base ophthalmic ointments containing 1 and 3% ACV did not produce significant ocular irritation when applied to the corneas of New Zealand White rabbits 5 times each day for 21 consecutive days. A 6% petrolatum base ointment produced mild conjunctival irritation but no sign of corneal or iridic toxicity. Mean concentrations of 2.53 microM ACV were found in aqueous humor 2 hours after a 1 cm ribbon (21 mg) of 3% ophthalmic ointment was placed in the eyes of rabbits. A single treatment with a topical ointment containing 5% ACV in polyethylene glycol vehicle produced minimal irritation when placed in the eyes of New Zealand White rabbits. PMID:6662298

Tucker, W E; Johnston, R E; Macklin, A W; Szot, R J; Elion, G B; de Miranda, P; Szczech, G M

1983-01-01

32

Preclinical studies of alcohol binge drinking  

PubMed Central

Binge drinking is prevalent and has serious biomedical consequences. In children, adolescents, and young adults, it is a prominent risk factor for later development of alcohol-use disorders. Many preclinical models have been employed to study the genetic risks for and biomedical consequences of alcohol drinking. However, these models historically did not result in blood-alcohol concentrations (BACs) exceding 80 mg%; this relatively modest level is the threshold that currently defines a binge session, according to the NIAAA and CDC. Nevertheless, in alcohol-dependent rodents, binge drinking has been well documented. Key neurobiological substrates localized to brain reward and stress systems have been identified. Studies of newer models of binge drinking without dependence are reviewed here. In these models, rodents, non-human primates, and flies will drink enough to reach high BACs. They often display observable signs of intoxication. The neurobiological consequences of these episodes of binge drinking without dependence are reviewed, preliminary evidence for roles for GABA, glutamate, opioid peptides, and corticotropin releasing factor are discussed, as is the need for more work to identify the antecedents and consequences of binge drinking in both animal models and humans.

Crabbe, John C.; Harris, R. Adron; Koob, George F.

2011-01-01

33

TOXICOLOGICAL STUDIES OF SMOKE OBSCURANTS  

EPA Science Inventory

An exposure facility was designed and constructed to support health effect studies of inhaled smoke obscurants generated from light lubricating oils. Concentrations are monitored using gravimetric filter sample analysis and continuous RAM-1 aerosol monitors. Chemical consistency ...

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

Toxicological study of Balacaturbhadrika churna.  

PubMed

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. PMID:21760693

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

2011-04-01

36

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

37

Preclinical anticancer effects and toxicologic assessment of hepatic artery infusion of fine-powder cisplatin with lipiodol in vivo.  

PubMed

We conducted an in vivo study to evaluate the anticancer effect and toxicity of fine-powder cisplatin suspended in lipiodol (fCDDP/LPD suspension) after a single administration of three different doses to rats via the intrahepatic artery after transplantation of rat ascites hepatoma cells. The toxicity of the fCDDP/LPD suspension was also assessed in the same protocol in noncancer-bearing rats and the observed toxicologic changes were compared among groups administered saline (Sal), an aqueous solution of fCDDP (fCDDP/Sal solution), and LPD alone. In parallel with the toxicity test, plasma CDDP concentrations were compared between the fCDDP/LPD suspension and fCDDP/Sal solution. The mean weight of the tumors in the fCDDP/LPD suspension groups was significantly less than in the LPD-alone group. The pathologic changes in the liver observed in the fCDDP/LPD suspension group increased with dose, were more marked compared with those in the fCDDP/Sal solution and LPD-alone groups, and were reversible. No other toxicologic effects were observed. The concentration of CDDP in the plasma in the fCDDP/LPD suspension group was slightly lower than that in the fCDDP/Sal solution group. In conclusion, the results indicate that the fCDDP/LPD suspension has sufficient anticancer efficacy and tolerability for use in the clinical treatment of hepatocellular carcinoma. PMID:24270385

Yamaguchi, T; Nakajima, N; Nakamura, I; Mashiba, H; Kawashiro, T; Ebara, K; Ichimura, E; Nishimura, C; Okamoto, K; Ichikawa, Y; Ichida, T

2013-10-01

38

Toxicological studies on plant proteins: a review.  

PubMed

Nowadays, toxicological studies are contributing to human health more than ever. Reports on the toxicological studies of plant proteins, which are continuously growing in number in the literature, have been reviewed. Two important aspects are discussed: dietary safety evaluation, including toxicity tests and the maximum daily intake allowance, and the appropriate proportion in our daily diets of proteins from traditional foods and of new proteins from plant sources not traditionally employed as foods. Water hyacinth leaf proteins, sweet lupin proteins and canola proteins have not been shown to be toxic, although they are not traditionally employed as food proteins. These findings are very important for exploiting valuable new protein sources that are suitable for human or animal consumption and applicable to the food industry. Acutely toxic proteins, including lectins, ribosome-inactivating proteins, inhibitors of proteolytic enzymes and glycohydro-lases, have been isolated from plant materials and identified. Their toxicities and molecular characteristics have been described. The toxicity of proteins depends upon their specific native structures. Once they are denatured by appropriate treatment, such as heating, their toxicity can be reduced or even eliminated. These findings indicate that raw materials that contain this kind of toxic protein are not edible. However, after proper processing, they may be suitable for human or animal consumption. Although the toxicities of type 2 ribosome-inactivating proteins reported by different authors vary, the maximum dosages are still trace amounts. PMID:22183867

Wu, Wenbiao; Sun, Rong

2012-06-01

39

USHERING IN THE STUDY AND TREATMENT OF PRECLINICAL ALZHEIMER DISEASE  

PubMed Central

Researchers have begun to characterize the subtle biological and cognitive processes that precede the clinical onset of Alzheimer disease (AD), and to set the stage for accelerated evaluation of experimental treatments to delay the onset, reduce the risk of or completely prevent clinical decline. Here, we provide an overview of the experimental strategies, and brain imaging and cerebrospinal fluid biomarker measures that are used in early detection and tracking of AD, highlighting at-risk individuals who could be suitable for preclinical monitoring. We discuss how these advances have contributed to reconceptualization of AD as a sequence of biological changes that occur during progression from preclinical AD, to mild cognitive impairment and finally dementia, and we review recently proposed research criteria for preclinical AD. Advances in the study of preclinical AD have driven the recognition that efficacy of at least some AD therapies may depend on initiation of treatment before clinical manifestation of disease, leading to a new era of AD prevention research.

Langbaum, Jessica B.S.; Fleisher, Adam S.; Chen, Kewei; Ayutyanont, Napatkamon; Lopera, Francisco; Quiroz, Yakeel T.; Caselli, Richard J.; Tariot, Pierre N.; Reiman, Eric M.

2014-01-01

40

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

41

Phase 2 Preclinical Toxicological Evaluation of Flavone Acetic Acid (NSC-347512) in CD2F1 Mice, Fischer 344 Rats, and Beagle Dogs.  

National Technical Information Service (NTIS)

Flavone acetic acid (NSC-347512) was tested in a series of preclinical toxicity studies. These studies were conducted in CD2F1 mice, Fischer 344 rats, and beagle dogs using both single and five daily intravenous dosing schedules. In mice, death was acute ...

A. M. El-Hawari M. A. Stedham L. Brennecke M. L. Stoltz S. E. Unwin

1985-01-01

42

Genetically engineered humanized mouse models for preclinical antibody studies.  

PubMed

The use of genetic engineering has vastly improved our capabilities to create animal models relevant in preclinical research. With the recent advances in gene-editing technologies, it is now possible to very rapidly create highly tunable mouse models as needs arise. Here, we provide an overview of genetic engineering methods, as well as the development of humanized neonatal Fc receptor (FcRn) models and their use for monoclonal antibody in vivo studies. PMID:24150980

Proetzel, Gabriele; Wiles, Michael V; Roopenian, Derry C

2014-04-01

43

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

44

Characterization of nanomaterials for toxicological studies.  

PubMed

The scientific community, regulatory agencies, environmentalists, and most industry representatives all agree that more effort is required to ensure the responsible and safe development of new nanotechnologies. Characterizing nanomaterials is a key aspect in this effort. There is no universally agreed upon minimum set of characteristics although certain common properties are included in most recommendations. Therefore, characterization becomes more like a puzzle put together with various measurements rather than a single straightforward analytical measurement. In this chapter, we emphasize and illustrate the important elements of nanoparticle characterization with a systematic approach to physicochemical characterization. We start with an overview describing the properties that are most significant to toxicological testing along with suggested methods for characterizing an as-received nanomaterial and then specifically address the measurement of size, surface properties, and imaging. PMID:22975954

Powers, Kevin W; Carpinone, Paul L; Siebein, Kerry N

2012-01-01

45

Pre-clinical pharmacokinetics and acute toxicological evaluation of a monastrol derivative anticancer candidate LaSOM 65 in rats.  

PubMed

1. The present work investigated the pharmacokinetic and tissue distribution as well as acute toxicity of a new chemical entity (NCE), the anticancer candidate LaSOM 65 in Wistar rats. 2. LaSOM 65 pharmacokinetics was investigated after intravenous (i.v., 1?mg/kg) and oral (p.o., 10 and 30?mg/kg) dosing. Tissue distribution was assessed after i.v. bolus dose. Acute toxicity was evaluated after i.v. (1, 2.5 and 5?mg/kg) and p.o. (50, 100 and 150?mg/kg) administration. 3. Short half-life (1.75?±?0.71?h), a clearance of 0.85?±?0.18?L/h/kg and a volume of distribution of 1.76?±?0.24?L/kg were observed after i.v. dosing. The compound showed good bioavailability and linear pharmacokinetics after oral doses. The NCE distributes consistently in lung and fatty tissues, with penetration ratios of 2.7 and 1.4, respectively. The other tissues investigated presented smaller penetration ratios. Adverse clinical symptoms were observed only after i.v. administration, and regressed 3?h after dosing. Compared with controls, no statistical differences were found for serum analysis, body weight and relative organ weight, indicating no acute toxicological effects. 4. Overall, LaSOM 65 showed good pharmacokinetic characteristics and no signs of acute toxicity, indicating that it is a promising anticancer candidate. PMID:23937080

Torres, Bruna G S; Uchôa, Flávia De Toni; Pigatto, Maiara C; Azeredo, Francine J; Haas, Sandra E; Dallegrave, Eliane; Canto, Rômulo F S; Eifler-Lima, Vera L; Dalla Costa, Teresa

2014-03-01

46

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

47

Experimental design and efficient parameter estimation in preclinical pharmacokinetic studies.  

PubMed

Monte Carlo simulation technique used to evaluate the effect of the arrangement of concentrations on the efficiency of estimation of population pharmacokinetic parameters in the preclinical setting is described. Although the simulations were restricted to the one compartment model with intravenous bolus input, they provide the basis of discussing some structural aspects involved in designing a destructive ("quantic") preclinical population pharmacokinetic study with a fixed sample size as is usually the case in such studies. The efficiency of parameter estimation obtained with sampling strategies based on the three and four time point designs were evaluated in terms of the percent prediction error, design number, individual and joint confidence intervals coverage for parameter estimates approaches, and correlation analysis. The data sets contained random terms for both inter- and residual intra-animal variability. The results showed that the typical population parameter estimates for clearance and volume were efficiently (accurately and precisely) estimated for both designs, while interanimal variability (the only random effect parameter that could be estimated) was inefficiently (inaccurately and imprecisely) estimated with most sampling schedules of the two designs. The exact location of the third and fourth time point for the three and four time point designs, respectively, was not critical to the efficiency of overall estimation of all population parameters of the model. However, some individual population pharmacokinetic parameters were sensitive to the location of these times. PMID:7479560

Ette, E I; Howie, C A; Kelman, A W; Whiting, B

1995-05-01

48

DTP | Toxicology and Pharmacology Branch (TPB)  

Cancer.gov

Hendriks, H.R., J. Plowman, D.P. Berger, K.D. Paull, H.H. Fiebig, Ø. Fodstat, H.C. Dreef-van der Meulen, R.E.C. Henrar, H.M. Pinedo and G. Schwartsmann, 1992. Preclinical Antitumor Activity and Animal Toxicology Studies of Rhizoxin, a Novel Tubulin-interacting Agent, Annals of Oncol., 3, 755-763.

49

Kidney Injury Molecule-1 Outperforms Traditional Biomarkers of Kidney Injury in Multi-site Preclinical Biomarker Qualification Studies  

PubMed Central

Kidney toxicity accounts for a significant percentage of morbidity and drug candidate failure. Serum creatinine (SCr) and blood urea nitrogen (BUN) have been used to monitor kidney dysfunction for over a century but these markers are insensitive and non-specific. In multi-site preclinical rat toxicology studies the diagnostic performance of urinary kidney injury molecule-1 (Kim-1) was compared to traditional biomarkers as predictors of kidney tubular histopathologic changes, currently considered the “gold standard” of nephrotoxicity. In multiple models of kidney injury, urinary Kim-1 significantly outperformed SCr and BUN. The area under the receiver operating characteristic curve for Kim-1 was between 0.91 and 0.99 as compared to 0.79 to 0.9 for BUN and 0.73 to 0.85 for SCr. Thus urinary Kim-1 is the first injury biomarker of kidney toxicity qualified by the FDA and EMEA and is expected to significantly improve kidney safety monitoring.

Vaidya, Vishal S.; Ozer, Josef S.; Frank, Dieterle; Collings, Fitz B.; Ramirez, Victoria; Troth, Sean; Muniappa, Nagaraja; Thudium, Douglas; Gerhold, David; Holder, Daniel J.; Bobadilla, Norma A.; Marrer, Estelle; Perentes, Elias; Cordier, Andre; Vonderscher, Jacky; Maurer, Gerard; Goering, Peter L.; Sistare, Frank D.; Bonventre, Joseph V.

2010-01-01

50

A toxicological study of gadolinium nitrate  

SciTech Connect

The sensitization study in the guinea pig did not show gadolinium nitrate to have potential sensitizing properties. Skin application studies in the rabbit demonstrated that it was cutaneously a severe irritant. This material was considered an irritant in the rabbit eye application studies. 3 refs., 1 tab.

London, J.E.

1988-05-01

51

Toxicologic Studies with Daunomycin (Nsc-82151).  

National Technical Information Service (NTIS)

The report summarizes single intraperitoneal dose studies in BALB/c mice; single dose, two week repeated dose and weekly repeated dose studies in beagles; and two week repeated dose studies in African green monkeys. Four dogs received 12 daily 0.5 mg/kg i...

R. K. Morrison D. E. Brown E. K. Timmens M. Catillo

1967-01-01

52

Characterization of Liposarcoma Cell Lines for Preclinical and Biological Studies  

PubMed Central

Liposarcoma cell lines represent in vitro models for studying disease mechanisms at the cellular level and for preclinical evaluation of novel drugs. To date there are a limited number of well-characterized models available. In this study, nine immortal liposarcoma cell lines were evaluated for tumor-forming ability, stem cell- and differentiation potential, and metastatic potential, with the aim to generate a well-characterized liposarcoma cell line panel. Detailed stem cell and differentiation marker analyses were also performed. Five of the liposarcoma cell lines were tumorigenic, forming tumors in mice. Interestingly, tumor-forming ability correlated with high proliferative capacity in vitro. All the cell lines underwent adipocytic differentiation, but the degree varied. Surprisingly, the expression of stem cell and differentiation markers did not correlate well with function. Overall, the panel contains cell lines suited for in vivo analyses (LPS141, SA-4, T778, SW872, and LISA-2), for testing novel drugs targeting cancer stem cells (LPS141) and for studying tumor progression and metastasis (T449 and T778).

Stratford, Eva W.; Castro, Russell; Daffinrud, Jeanette; Skarn, Magne; Lauvrak, Silje; Munthe, Else; Myklebost, Ola

2012-01-01

53

Preclinical studies for induced pluripotent stem cell-based therapeutics.  

PubMed

Induced pluripotent stem cells (iPSCs) and their differentiated derivatives can potentially be applied to cell-based therapy for human diseases. The properties of iPSCs are being studied intensively both to understand the basic biology of pluripotency and cellular differentiation and to solve problems associated with therapeutic applications. Examples of specific preclinical applications summarized briefly in this minireview include the use of iPSCs to treat diseases of the liver, nervous system, eye, and heart and metabolic conditions such as diabetes. Early stage studies illustrate the potential of iPSC-derived cells and have identified several challenges that must be addressed before moving to clinical trials. These include rigorous quality control and efficient production of required cell populations, improvement of cell survival and engraftment, and development of technologies to monitor transplanted cell behavior for extended periods of time. Problems related to immune rejection, genetic instability, and tumorigenicity must be solved. Testing the efficacy of iPSC-based therapies requires further improvement of animal models precisely recapitulating human disease conditions. PMID:24362021

Harding, John; Mirochnitchenko, Oleg

2014-02-21

54

[Felines: an alternative in genetic toxicology studies?].  

PubMed

The micronuclei (MN) test carry out in peripheral blood is fast, simple, economic and it is used to detect genotoxic environmental agents. MN are fragments of chromosomes or complete chromosomes remaining in the cytoplasm after cell division, which increase when organisms are exposed to genotoxic agents. Therefore, species with the highest values of spontaneous micronucleated erythrocytes (MNE) are the most suitable to be potentials biomonitor of micronucleogenic agents, using a drop of blood. Nine species of Felines that present spontaneous MNE in peripheral blood are shown. From these species, the cat has been previously proven, with positive results and also lion (Panthera leo), yaguaroundi (Felis yagoaroundi), lynx (Lynx ruffus), jaguar (Panthera onca), puma (Puma concolor), tiger (Panthera tigris), ocelote (Felis padalis) and leopard (Panthera pardus) display spontaneous MNE, and with this characteristic this Family can be propose like a potential group to be used in toxicogenetic studies. PMID:19256458

Zamora-Perez, Ana; Gómez-Meda, Belinda C; Ramos-Ibarra, Maria L; Batista-González, Cecilia M; Luna-Aguirre, Jaime; González-Rodríguez, Andrés; Rodríguez-Avila, José L; Zúñiga-González, Guillermo M

2008-06-01

55

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

2013-09-01

56

[Toxicological studies of Bulgarian activated bentonite].  

PubMed

We studied the endurance of calves, lambs and pigs as well as the acute, subchronic and chronic toxicity for chickens with regard to bentonite of local origin, extra activated in a physico-chemical way. It was proved that the medicine was rather endurable with calves, lambs and pigs without causing intoxication or death after a single internal introduction in doses respectively 4138, 4130 and 1860 mg/kg t. LD0 of the activated bentonite for the chickens in the case of intra-crop application was over 18000 mg/kg t. During a 33-day extra addition to the fodder of chickens in quantities of 2 and 6% and during a 90-day introduction into concentrations 1, 3 and 5% the activated bentonite and not provoke any changes in the behaviour, overall state and in the clinical biochemical and electrolytic composition (Ca, P, K, Na) of the blood, but it caused suppression of growth ranging from 6 to 27% and brought about a higher expenditure of food for a single growth unit ranging from 4.7 to 12.1%. This was also observed when it was added to the morning ration of pigs in doses 1 and 5% (6 and 30 d/pig) without any influence over the health state of the pigs, but it slowed down growth ranging from 17.2 to 21.3% and a lower utilization of the fodder taken by 19 to 26%. PMID:7222463

Drumev, D; Donev, B; Dimitrov, K; Dilov, P; Dzhurov, A

1980-01-01

57

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

58

Seprafilm® adhesion barrier: (1) a review of preclinical, animal, and human investigational studies.  

PubMed

The aim of this study was to provide a single site resource for investigators, clinicians, and others seeking preclinical, animal, and human investigational studies concerning the postsurgical, anti-adhesion barrier Seprafilm™ (Genzyme Corporation, Cambridge, MA). All published preclinical, animal, human extra-abdominal research as of July 2011 have been summarized and included in this document. Searches of Medline and EMBASE Drugs and Pharmaceuticals databases were conducted for original preclinical, animal, and human extra-abdominal studies involving Seprafilm. Preclinical, animal, and extra-abdominal human investigational studies are the study selection for this manuscript. Intraabdominal use is discussed in the accompanying manuscript. Data extraction includes systematic manuscript review. Summary of preclinical, animal, and extra-abdominal human investigational use of Seprafilm by surgical discipline were gathered for data synthesis. The clinical use of Seprafilm, which was approved by the FDA for intra-abdominal procedures, is supported by preclinical and animal studies relating to general surgical and obstetrical/gynecological applications. Findings from preclinical, animal, and human investigational studies at other sites throughout the body raises the potential for additional human clinical trials to assess efficacy and safety following surgical procedures at non-abdominal locations. PMID:22837732

Diamond, Michael P; Burns, Ellen L; Accomando, Beverly; Mian, Sadiqa; Holmdahl, Lena

2012-09-01

59

Developmental Toxicology Evaluations--Issues with Including Neurotoxicology and Immunotoxicology Assessments in Reproductive Toxicology Studies  

Microsoft Academic Search

Developmental and reproductive toxicology (DART) has rou- tinely been a part of safety assessment. Attention is now focused on the effects of chemicals on the developing nervous and immune systems. This focus on developmental neurotoxicology (DNT) and developmental immunotoxicology (DIT) is based on the premise that children differ from adults in some aspects of their biology and, thus, may also

Gregory S. Ladics; Robert E. Chapin; Kenneth L. Hastings; Michael P. Holsapple; Susan L. Makris

2005-01-01

60

A crowdsourcing model for creating preclinical medical education study tools.  

PubMed

During their preclinical course work, medical students must memorize and recall substantial amounts of information. Recent trends in medical education emphasize collaboration through team-based learning. In the technology world, the trend toward collaboration has been characterized by the crowdsourcing movement. In 2011, the authors developed an innovative approach to team-based learning that combined students' use of flashcards to master large volumes of content with a crowdsourcing model, using a simple informatics system to enable those students to share in the effort of generating concise, high-yield study materials. The authors used Google Drive and developed a simple Java software program that enabled students to simultaneously access and edit sets of questions and answers in the form of flashcards. Through this crowdsourcing model, medical students in the class of 2014 at the Johns Hopkins University School of Medicine created a database of over 16,000 questions that corresponded to the Genes to Society basic science curriculum. An analysis of exam scores revealed that students in the class of 2014 outperformed those in the class of 2013, who did not have access to the flashcard system, and a survey of students demonstrated that users were generally satisfied with the system and found it a valuable study tool. In this article, the authors describe the development and implementation of their crowdsourcing model for creating study materials, emphasize its simplicity and user-friendliness, describe its impact on students' exam performance, and discuss how students in any educational discipline could implement a similar model of collaborative learning. PMID:23619061

Bow, Hansen C; Dattilo, Jonathan R; Jonas, Andrea M; Lehmann, Christoph U

2013-06-01

61

Preclinical Studies of Signaling Pathways in a Mutant Mouse Model of Hormone-Refractory Prostate Cancer.  

National Technical Information Service (NTIS)

We have been investigating targeted therapies for the treatment of advanced prostate cancer using a genetically engineered mouse model of the disease. Based on previous studies, we performed pre-clinical studies to examine the consequences of combinatoria...

C. Abate-Shen

2009-01-01

62

Mechanistic studies: their role in the toxicological evaluation of pesticides.  

PubMed

To date, studies on the mechanism of toxicity of pesticides are not yet an integral part of the toxicological evaluation process. However, in recent years mechanistic studies have played an increasing role in the assessment of toxicological hazards to man, and in this paper we have described two examples where an understanding of mechanism has contributed positively to risk assessment or has provided a surer scientific basis for the judgement of whether a potential hazard will be expressed in man. In the first example, an evaluation of the scientific literature leads to the conclusion that hepatic peroxisome proliferation in rats and mice is directly, or indirectly, related to the development of hepatocellular tumours. A wide range of non-mutagenic chemicals elicit peroxisome proliferation in mouse and rat liver, but not the guinea pig or marmoset liver. Using one of the diphenyl ether herbicides, fomesafen, we have shown that isolated hepatocytes from mice and rats, but not those from guinea pigs, marmosets and significantly man, undergo peroxisome proliferation. Therefore, it seems reasonable to conclude that although fomesafen causes peroxisome-related tumours in the mouse, man is neither susceptible nor sensitive to this mechanism. Consequently, we can conclude that fomesafen will not cause liver tumours in humans exposed to this herbicide. The herbicide paraquat, although safe in normal agricultural use, has been responsible for numerous human fatalities, almost exclusively as a result of the intentional ingestion of the concentrated commercial product.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2689246

Smith, L L; Elcombe, C R

1989-01-01

63

Mouse Model for the Preclinical Study of Metastatic Disease  

Cancer.gov

The successful development of new cancer therapeutics requires reliable preclinical data that are obtained from mouse models for cancer. Human tumor xenografts, which require transplantation of human tumor cells into an immune compromised mouse, represent the current standard mouse model for cancer. Since the immune system plays an important role in tumor growth, progression and metastasis, the current standard mouse model is not ideal for accurate prediction of therapeutic effectiveness in patients.

64

Characterization of Reference Artemia III for Marine Toxicological Studies.  

National Technical Information Service (NTIS)

ASTM Practice for Using Brine Shrimp Nauplii as Food for Test Animals in Aquatic Toxicology Tests (E 1203) suggests use of Reference Artemia as a reference standard for evaluating other batches of brine shrimp as food for organisms used in toxicology. In ...

G. A. Collins D. A. Bengtson J. C. Moore

1993-01-01

65

Zebrafish as a model system to study toxicology.  

PubMed

Monitoring and assessing the effects of contaminants in the aquatic eco-environment is critical in protecting human health and the environment. The zebrafish has been widely used as a prominent model organism in different fields because of its small size, low cost, diverse adaptability, short breeding cycle, high fecundity, and transparent embryos. Recent studies have demonstrated that zebrafish sensitivity can aid in monitoring environmental contaminants, especially with the application of transgenic technology in this area. The present review provides a brief overview of recent studies on wild-type and transgenic zebrafish as a model system to monitor toxic heavy metals, endocrine disruptors, and organic pollutants for toxicology. The authors address the new direction of developing high-throughput detection of genetically modified transparent zebrafish to open a new window for monitoring environmental pollutants. PMID:24307630

Dai, Yu-Jie; Jia, Yong-Fang; Chen, Na; Bian, Wan-Ping; Li, Qin-Kai; Ma, Yan-Bo; Chen, Yan-Ling; Pei, De-Sheng

2014-01-01

66

THE USE OF STEM CELLS FOR TOXICOLOGY STUDIES AND RISK ASSESSMENTS  

EPA Science Inventory

In general terms, toxicology studies are used in support of risk assessments of adverse health outcomes as a result of exposures to chemical and physical agents. In particular, toxicological data are used to provide information that aids in the assessment of disease outcomes at e...

67

Developmental Toxicology##  

EPA Science Inventory

Developmental toxicology encompasses the study of developmental exposures, pharmacokinetics, mechanisms, pathogenesis, and outcomes potentially leading to adverse health effects. Manifestations of developmental toxicity include structural malformations, growth retardation, functi...

68

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

69

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

2011-01-01

70

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...

71

International recommendations for training future toxicologic pathologists participating in regulatory-type, nonclinical toxicity studies.  

PubMed

The International Federation of Societies of Toxicologic Pathologists (IFSTP) proposes a common global framework for training future toxicologic pathologists who will support regulatory-type nonclinical toxicology studies. Trainees optimally should undertake a scientific curriculum of at least 5 years at an accredited institution leading to a clinical degree (veterinary medicine or medicine). Trainees should then obtain 4 or more years of intensive pathology practice during a residency and/or on-the-job "apprenticeship," at least 2 years of which must be focused on regulatory-type toxicologic pathology topics. Possession of a recognized pathology qualification (i.e., certification) is highly recommended. A non-clinical pathway (e.g., a graduate degree in medical biology or pathology) may be possible if medically trained pathologists are scarce, but this option is not optimal. Regular, lifelong continuing education (peer review of nonclinical studies, professional meetings, reading, short courses) will be necessary to maintain and enhance one's understanding of current toxicologic pathology knowledge, skills, and tools. This framework should provide a rigorous yet flexible way to reliably train future toxicologic pathologists to generate, interpret, integrate, and communicate data in regulatory-type, nonclinical toxicology studies. PMID:22272030

Bolon, Brad; Barale-Thomas, Erio; Bradley, Alys; Ettlin, Robert A; Franchi, Carla A S; George, Catherine; Giusti, Anna Maria; Hall, Robert; Jacobsen, Matthew; Konishi, Yoichi; Ledieu, David; Morton, Daniel; Park, Jae-Hak; Scudamore, Cheryl L; Tsuda, Hiroyuki; Vijayasarathi, S K; Wijnands, Marcel V W

2010-09-01

72

International Recommendations for Training Future Toxicologic Pathologists Participating in Regulatory-Type, Nonclinical Toxicity Studies*  

PubMed Central

The International Federation of Societies of Toxicologic Pathologists (IFSTP) proposes a common global framework for training future toxicologic pathologists who will support regulatory-type nonclinical toxicology studies. Trainees optimally should undertake a scientific curriculum of at least 5 years at an accredited institution leading to a clinical degree (veterinary medicine or medicine). Trainees should then obtain 4 or more years of intensive pathology practice during a residency and/or on-the-job “apprenticeship,” at least 2 years of which must be focused on regulatory-type toxicologic pathology topics. Possession of a recognized pathology qualification (i.e., certification) is highly recommended. A non-clinical pathway (e.g., a graduate degree in medical biology or pathology) may be possible if medically trained pathologists are scarce, but this option is not optimal. Regular, lifelong continuing education (peer review of nonclinical studies, professional meetings, reading, short courses) will be necessary to maintain and enhance one’s understanding of current toxicologic pathology knowledge, skills, and tools. This framework should provide a rigorous yet flexible way to reliably train future toxicologic pathologists to generate, interpret, integrate, and communicate data in regulatory-type, nonclinical toxicology studies.

Bolon, Brad; Barale-Thomas, Erio; Bradley, Alys; Ettlin, Robert A.; Franchi, Carla A.S.; George, Catherine; Giusti, Anna Maria; Hall, Robert; Jacobsen, Matthew; Konishi, Yoichi; Ledieu, David; Morton, Daniel; Park, Jae-Hak; Scudamore, Cheryl L.; Tsuda, Hiroyuki; Vijayasarathi, S.K.; Wijnands, Marcel V.W.

2010-01-01

73

International recommendations for training future toxicologic pathologists participating in regulatory-type, nonclinical toxicity studies.  

PubMed

The International Federation of Societies of Toxicologic Pathologists (IFSTP) proposes a common global framework for training future toxicologic pathologists who will support regulatory-type, nonclinical toxicology studies. Optimally, trainees should undertake a scientific curriculum of at least five years at an accredited institution leading to a clinical degree (veterinary medicine or medicine). Trainees should then obtain four or more years of intensive pathology practice during a residency and/or on-the-job "apprenticeship," at least two years of which must be focused on regulatory-type toxicologic pathology topics. Possession of a recognized pathology qualification (i.e., certification) is highly recommended. A nonclinical pathway (e.g., a graduate degree in medical biology or pathology) may be possible if medically trained pathologists are scarce, but this option is not optimal. Regular, lifelong continuing education (peer review of nonclinical studies, professional meetings, reading, short courses) will be necessary to maintain and enhance one's understanding of current toxicologic pathology knowledge, skills, and tools. This framework should provide a rigorous yet flexible way to reliably train future toxicologic pathologists to generate, interpret, integrate, and communicate data in regulatory-type, nonclinical toxicology studies. PMID:20716784

Bolon Chair, Brad; Barale-Thomas, Erio; Bradley, Alys; Ettlin, Robert A; Franchi, Carla A S; George, Catherine; Giusti, Anna Maria; Hall, Robert; Jacobsen, Matthew; Konishi, Yoichi; Ledieu, David; Morton, Daniel; Park, Jae-Hak; Scudamore, Cheryl L; Tsuda, Hiroyuki; Vijayasarathi, S K; Wijnands, Marcel V W

2010-10-01

74

International recommendations for training future toxicologic pathologists participating in regulatory-type, nonclinical toxicity studies.  

PubMed

The International Federation of Societies of Toxicologic Pathologists (IFSTP) proposes a common global framework for training future toxicologic pathologists who will support regulatory-type - nonclinical toxicology studies. Trainees optimally should undertake a scientific curriculum of at least 5 years at an accredited institution leading to a clinical degree (veterinary medicine or medicine). Trainees should then obtain 4 or more years of intensive pathology practice during a residency and/or on-the-job "apprenticeship," at least 2 years of which must be focused on regulatory-type toxicologic pathology topics. Possession of a recognized pathology qualification (i.e., certification) is highly recommended. A nonclinical pathway (e.g., a graduate degree in medical biology or pathology) may be possible if medically trained pathologists are scarce, but this option is not optimal. Regular, lifelong continuing education (peer review of nonclinical studies, professional meetings, reading, short courses) will be necessary to maintain and enhance one's understanding of current toxicologic pathology knowledge, skills, and tools. This framework should provide a rigorous yet flexible way to reliably train future toxicologic pathologists to generate, interpret, integrate, and communicate data in regulatory-type, nonclinical toxicology studies. PMID:20724123

Bolon, Brad; Barale-Thomas, Erio; Bradley, Alys; Ettlin, Robert A; Franchi, Carla A S; George, Catherine; Giusti, Anna Maria; Hall, Robert; Jacobsen, Matthew; Konishi, Yoichi; Ledieu, David; Morton, Daniel; Park, Jae-Hak; Scudamore, Cheryl L; Tsuda, Hiroyuki; Vijayasarathi, S K; Wijnands, Marcel V W

2011-01-01

75

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

76

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

2013-10-01

77

Novel Epigenetic Target Therapy for Prostate Cancer: A Preclinical Study  

PubMed Central

Epigenetic events are critical contributors to the pathogenesis of cancer, and targeting epigenetic mechanisms represents a novel strategy in anticancer therapy. Classic demethylating agents, such as 5-Aza-2?-deoxycytidine (Decitabine), hold the potential for reprograming somatic cancer cells demonstrating high therapeutic efficacy in haematological malignancies. On the other hand, epigenetic treatment of solid tumours often gives rise to undesired cytotoxic side effects. Appropriate delivery systems able to enrich Decitabine at the site of action and improve its bioavailability would reduce the incidence of toxicity on healthy tissues. In this work we provide preclinical evidences of a safe, versatile and efficient targeted epigenetic therapy to treat hormone sensitive (LNCap) and hormone refractory (DU145) prostate cancers. A novel Decitabine formulation, based on the use of engineered erythrocyte (Erythro-Magneto-Hemagglutinin Virosomes, EMHVs) drug delivery system (DDS) carrying this drug, has been refined. Inside the EMHVs, the drug was shielded from the environment and phosphorylated in its active form. The novel magnetic EMHV DDS, endowed with fusogenic protein, improved the stability of the carried drug and exhibited a high efficiency in confining its delivery at the site of action in vivo by applying an external static magnetic field. Here we show that Decitabine loaded into EMHVs induces a significant tumour mass reduction in prostate cancer xenograft models at a concentration, which is seven hundred times lower than the therapeutic dose, suggesting an improved pharmacokinetics/pharmacodynamics of drug. These results are relevant for and discussed in light of developing personalised autologous therapies and innovative clinical approach for the treatment of solid tumours.

Gherardini, Lisa; Pelosi, Gualtiero; Viglione, Federica; Grimaldi, Settimio; Pani, Luca; Cinti, Caterina

2014-01-01

78

Novel epigenetic target therapy for prostate cancer: a preclinical study.  

PubMed

Epigenetic events are critical contributors to the pathogenesis of cancer, and targeting epigenetic mechanisms represents a novel strategy in anticancer therapy. Classic demethylating agents, such as 5-Aza-2'-deoxycytidine (Decitabine), hold the potential for reprograming somatic cancer cells demonstrating high therapeutic efficacy in haematological malignancies. On the other hand, epigenetic treatment of solid tumours often gives rise to undesired cytotoxic side effects. Appropriate delivery systems able to enrich Decitabine at the site of action and improve its bioavailability would reduce the incidence of toxicity on healthy tissues. In this work we provide preclinical evidences of a safe, versatile and efficient targeted epigenetic therapy to treat hormone sensitive (LNCap) and hormone refractory (DU145) prostate cancers. A novel Decitabine formulation, based on the use of engineered erythrocyte (Erythro-Magneto-Hemagglutinin Virosomes, EMHVs) drug delivery system (DDS) carrying this drug, has been refined. Inside the EMHVs, the drug was shielded from the environment and phosphorylated in its active form. The novel magnetic EMHV DDS, endowed with fusogenic protein, improved the stability of the carried drug and exhibited a high efficiency in confining its delivery at the site of action in vivo by applying an external static magnetic field. Here we show that Decitabine loaded into EMHVs induces a significant tumour mass reduction in prostate cancer xenograft models at a concentration, which is seven hundred times lower than the therapeutic dose, suggesting an improved pharmacokinetics/pharmacodynamics of drug. These results are relevant for and discussed in light of developing personalised autologous therapies and innovative clinical approach for the treatment of solid tumours. PMID:24851905

Naldi, Ilaria; Taranta, Monia; Gherardini, Lisa; Pelosi, Gualtiero; Viglione, Federica; Grimaldi, Settimio; Pani, Luca; Cinti, Caterina

2014-01-01

79

Application of toxicogenomics in hepatic systems toxicology for risk assessment: Acetaminophen as a case study  

SciTech Connect

Hepatic systems toxicology is the integrative analysis of toxicogenomic technologies, e.g., transcriptomics, proteomics, and metabolomics, in combination with traditional toxicology measures to improve the understanding of mechanisms of hepatotoxic action. Hepatic toxicology studies that have employed toxicogenomic technologies to date have already provided a proof of principle for the value of hepatic systems toxicology in hazard identification. In the present review, acetaminophen is used as a model compound to discuss the application of toxicogenomics in hepatic systems toxicology for its potential role in the risk assessment process, to progress from hazard identification towards hazard characterization. The toxicogenomics-based parallelogram is used to identify current achievements and limitations of acetaminophen toxicogenomic in vivo and in vitro studies for in vitro-to-in vivo and interspecies comparisons, with the ultimate aim to extrapolate animal studies to humans in vivo. This article provides a model for comparison of more species and more in vitro models enhancing the robustness of common toxicogenomic responses and their relevance to human risk assessment. To progress to quantitative dose-response analysis needed for hazard characterization, in hepatic systems toxicology studies, generation of toxicogenomic data of multiple doses/concentrations and time points is required. Newly developed bioinformatics tools for quantitative analysis of toxicogenomic data can aid in the elucidation of dose-responsive effects. The challenge herein is to assess which toxicogenomic responses are relevant for induction of the apical effect and whether perturbations are sufficient for the induction of downstream events, eventually causing toxicity.

Kienhuis, Anne S., E-mail: anne.kienhuis@rivm.nl [Laboratory for Health Protection Research, National Institute of Public Health and the Environment (RIVM), PO Box 1, 3720 BA Bilthoven (Netherlands); RIKILT, Institute of Food Safety, Wageningen UR, PO Box 230, 6700 AE, Wageningen (Netherlands); Netherlands Toxicogenomics Centre (NTC), Maastricht University, PO Box 616, 6200 MD, Maastricht (Netherlands); Bessems, Jos G.M., E-mail: jos.bessems@rivm.nl [Centre for Substances and Integrated Risk Assessment, National Institute of Public Health and the Environment (RIVM), PO Box 1, 3720 BA Bilthoven (Netherlands); Pennings, Jeroen L.A., E-mail: jeroen.pennings@rivm.nl [Laboratory for Health Protection Research, National Institute of Public Health and the Environment (RIVM), PO Box 1, 3720 BA Bilthoven (Netherlands); Netherlands Toxicogenomics Centre (NTC), Maastricht University, PO Box 616, 6200 MD, Maastricht (Netherlands); Driessen, Marja, E-mail: marja.driessen@rivm.nl [Laboratory for Health Protection Research, National Institute of Public Health and the Environment (RIVM), PO Box 1, 3720 BA Bilthoven (Netherlands); Netherlands Toxicogenomics Centre (NTC), Maastricht University, PO Box 616, 6200 MD, Maastricht (Netherlands); Division of Toxicology, Leiden/Amsterdam Center for Drug Research, Leiden University, 2300 RA, Leiden (Netherlands); Luijten, Mirjam, E-mail: mirjam.luijten@rivm.nl [Laboratory for Health Protection Research, National Institute of Public Health and the Environment (RIVM), PO Box 1, 3720 BA Bilthoven (Netherlands); Netherlands Toxicogenomics Centre (NTC), Maastricht University, PO Box 616, 6200 MD, Maastricht (Netherlands); Delft, Joost H.M. van, E-mail: j.vandelft@grat.unimaas.nl [Netherlands Toxicogenomics Centre (NTC), Maastricht University, PO Box 616, 6200 MD, Maastricht (Netherlands); Department of Health Risk Analysis and Toxicology, Maastricht University, PO Box 616, 6200 MD, Maastricht (Netherlands)

2011-01-15

80

Exploratory Study of Factors Related to Educational Scores of First Preclinical Year Medical Students  

ERIC Educational Resources Information Center

The relationships among the scores of major subjects taught in the first preclinical year of a Thai medical school, previous academic achievements, and daily life activities are rarely explored. We therefore performed an exploratory study identifying various factors possibly related to the educational scores of these medical students.…

Sitticharoon, Chantacha; Srisuma, Sorachai; Kanavitoon, Sawita; Summachiwakij, Sarawut

2014-01-01

81

An overview of the toxicology of HFA134a (1,1,1,2-tetrafluoroethane)  

Microsoft Academic Search

1 This paper reviews the results of preclinical toxicology studies on HFA-134a carried out by Glaxo Research and Development Ltd.2 A comprehensive range of studies was conducted in ani mal models suitable for the type of investigation.3 The inhalation route of administration was used in all in vivo studies (with the exception of local tolerance and sensitisation studies) as patients

DJ Alexander; SE Libretto

1995-01-01

82

[Developing and standardizing experimental protocols using human iPS-derived cells to predict adverse drug reactions in pre-clinical safety studies].  

PubMed

In this study, we have standardized experimental protocols to evaluate the possibility of using cells differentiated from human induced pluripotent stem cells (hiPSCs) in the pre-clinical studies for the drug approval processes. Cells differentiated from hiPSC, especially cardiomyocytes, neurons and hepatocytes, are expected to be used as new pharmacological and toxicological assay tools. Current preclinical test methods have limitations for predicting clinical adverse drug reactions. This is because of the so-called 'problem of species difference'. Drug-induced arrhythmia, cognitive impairment and hepatotoxicity which can't be predicted in pre-clinical studies are major causes of the high rate attrition of new-drug candidates in clinical studies and of withdrawal of products from the market. The development of new pre-clinical test methods using cells differentiated from hiPSCs would resolve these problems, in addition to solving the issue of "the replacement, refinement and reduction (3Rs)" of animal experiments. From 2010 to 2011, we surveyed companies belonging to the Japan Pharmaceutical Manufacturers Association (JPMA) and academic researchers about the usage of differentiated cells in their laboratories. We found that studies were performed using differentiated cells from different cell lines of hiPSC with laboratory-specific differentiation methods. The cells were cultured in various conditions and their activities were measured using different methods. This resulted in a variety of pharmacological responses of the cells. It is therefore impossible to compare reproducibility and ensure reliability of experiments using these cells. To utilize the cells in the drug approval processes, we need robust, standardized test methods to accurately reproduce these methods in all laboratories. We will then be able to compare and analyze the obtained results. Based on the survey, the Ministry of Health, Labor and Welfare funded our study. In our study, we standardize pharmacological methods among several laboratories, including our laboratory, to develop robust tests, using the same lot of cells, the same culture conditions, reference compounds, experimental protocols, and analysis methodology. In conclusion, to standardize robust test methods, we need a consistent supply of high-quality differentiated cells. Further, indexes to quantify the quality of the differentiated cells will be needed for their effective usage in the pre-clinical safety studies. PMID:24340667

Sekino, Yuko; Sato, Kaoru; Kanda, Yasunari; Ishida, Seiichi

2013-01-01

83

Bias in toxicology  

Microsoft Academic Search

The potential for bias, i.e., influences that cause results to deviate systematically from the truth is substantial both in\\u000a toxicological research and in the performance of standardized toxicological testing. In this contribution, major potential\\u000a sources of bias in toxicological research and testing are identified. Due to the lack of empirical studies of bias in toxicology,\\u000a very little is known about

Birgitte Wandall; Sven Ove Hansson; Christina Rudén

2007-01-01

84

Why Toxicology?  

NSDL National Science Digital Library

One of the reasons for studying toxicology at the high school level is its relevance to everyday life. On a daily basis we are confronted with news reports about toxic chemicals in our food, water, and environment. How do we decide which of these are worth worrying about? Too often these decisions are based on misconceptions about what is "safe" and what involves too great a risk. In learning about the basic concepts of toxicology, students will become better prepared to make reasoned decisions about issues such as these. This free selection also includes the Table of Contents and Introduction.

Trautmann, Nancy M.; Team, The E.

2001-01-01

85

Toxicological screening  

PubMed Central

Toxicity testing of new compounds is essential for drug development process. The preclinical toxicity testing on various biological systems reveals the species-, organ- and dose- specific toxic effects of an investigational product. The toxicity of substances can be observed by (a) studying the accidental exposures to a substance (b) in vitro studies using cells/ cell lines (c) in vivo exposure on experimental animals. This review mainly focuses on the various experimental animal models and methods used for toxicity testing of substances. The pre-clinical toxicity testing helps to calculate “No Observed Adverse Effect Level” which is needed to initiate the clinical evaluation of investigational products.

Parasuraman, S.

2011-01-01

86

National Cooperative Gallstone Study.  

National Technical Information Service (NTIS)

The study was divided into two phases: (1) the pre-clinical (Phase I) which included all organizational, protocol development, treatment center and service laboratory selections, and animal toxicology studies and (2) the clinical phase (Phase II). The cli...

1975-01-01

87

National Cooperative Gallstone Study.  

National Technical Information Service (NTIS)

The study was divided into two phases; (1) the pre-clinical (Phase I) which included all organizational, protocol development, treatment center and service laboratory selections, and animal toxicology studies and (2) the clinical phase (Phase II). The cli...

1977-01-01

88

A magnetic resonance (MR) compatible selective brain temperature manipulation system for preclinical study  

PubMed Central

There is overwhelming evidence that hypothermia can improve the outcome of an ischemic stroke. However, the most widely used systemic cooling method could lead to multiple side effects, while the incompatibility with magnetic resonance imaging of the present selective cooling methods highly limit their application in preclinical studies. In this study, we developed a magnetic resonance compatible selective brain temperature manipulation system for small animals, which can regulate brain temperature quickly and accurately for a desired period of time, while maintaining the normal body physiological conditions. This device was utilized to examine the relationship between T1 relaxation, cerebral blood flow, and temperature in brain tissue during magnetic resonance imaging of ischemic stroke. The results showed that this device can be an efficient brain temperature manipulation tool for preclinical studies needing local hypothermic or hyperthermic conditions.

Liu, Qingwei; Cai, Yu; Lin, Weili; Turner, Gregory H; An, Hongyu

2012-01-01

89

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

90

Organic acids and bases: Review of toxicological studies  

SciTech Connect

Organic acids and bases are among the most frequently used chemicals in the manufacturing industries. However, the toxicology of only a number of them has been fully characterized, and for fewer still have occupational exposure limits been established. This paper reviews the acute and chronic toxicity data of the organic acids and bases, and considers the mechanism by which these chemicals produce their effects. A methodology for establishing preliminary occupational exposure limits based on the physicochemical properties of these chemicals is presented. Workplace exposure limits for 20 organic acids and bases which currently have no exposure guidelines are suggested. Advice regarding appropriate medical treatment of exposure to these materials is discussed. 98 references.

Leung, H.W.; Paustenbach, D.J. (Union Carbide Corporation, Danbury, CT (USA))

1990-01-01

91

Types of studies used to support treatment recommendations in medical toxicology.  

PubMed

There are few controlled clinical trials in medical toxicology to guide treatment decisions. Given the relative paucity of definitive data, we determined the types of evidence used to support treatment recommendations given in three major toxicology textbooks. One author reviewed the acetaminophen, tricyclic antidepressant, calcium channel blocker plus any relevant antidote chapters in three textbooks: Goldfranks Toxicologic Emergencies, Critical Care Toxicology, and Medical Toxicology. We identified statements that gave a treatment recommendation and classified the citation using the following system: No citation, general review article, in vitro study, animal study, case reports (n<3), case series (n>2), retrospective study, prospective observational study, and controlled clinical trial. Proportions for each type of citation with 95% confidence intervals were determined. We identified 469 treatment recommendations. We could not classify 57/742 citations. A large number of statements were not referenced (14%, 95% CI 12-17%). The most common citation types were case reports (28%, 95% CI 25-31%) and animal studies (18%, 16-21%). The proportions for the remaining types of citations were: review article (9%, 7-11%), clinical trials (9%, 7-11%), retrospective studies (8%, 6-10%), prospective observational studies (5%, 3-6%), and case series (4%, 3-6%). There is a need for more systematic studies of poisoned patients. As case reports are commonly used to support treatment recommendations, they should be held to rigorous scientific standards and include information to assess the validity of the conclusions. Case reports and animal studies are commonly used as evidence to support treatment recommendations in medical toxicology textbooks. PMID:20405268

Chuang, Ryan; Heard, Kennon J

2010-09-01

92

Preclinical Pharmacodynamic and Pharmacokinetic Studies of Investigational New Drugs.  

National Technical Information Service (NTIS)

During the past year of the contract, a study was initiated to evaluate, in dogs, whether significant clinical or pharmacological interactions occur when single oral doses of the antimalarial drug WR238605 are given in combination with one of the followin...

P. Noker

1996-01-01

93

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

94

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

95

JAK2 inhibitor therapy in myeloproliferative disorders: rationale, preclinical studies and ongoing clinical trials  

Microsoft Academic Search

The recent identification of somatic mutations such as JAK2V617F that deregulate Janus kinase (JAK)–signal transducer and activator of transcription signaling has spurred development of orally bioavailable small-molecule inhibitors that selectively target JAK2 kinase as an approach to pathogenesis-directed therapy of myeloproliferative disorders (MPD). In pre-clinical studies, these compounds inhibit JAK2V617F-mediated cell growth at nanomolar concentrations, and in vivo therapeutic efficacy

A Pardanani

2008-01-01

96

In Vitro Preclinical Evaluation Studies with the Echinocandin Antifungal MK-0991 (L-743,872)  

Microsoft Academic Search

The echinocandin MK-0991, formerly L-743,872, is a water-soluble lipopeptide that has been demonstrated in preclinical studies to have potent activity against Candida spp., Aspergillus fumigatus, and Pneumocystis carinii. An extensive in vitro biological evaluation of MK-0991 was performed to better define the potential activities of this novel compound. Susceptibility testing with MK-0991 against approximately 200 clinical isolates of Candida, Cryptococcus

KEN BARTIZAL; CHARLES J. GILL; GEORGE K. ABRUZZO; AMY M. FLATTERY; LI KONG; PATRICIA M. SCOTT; JEFFREY G. SMITH; CLAIRE E. LEIGHTON; AILEEN BOUFFARD; JAMES F. DROPINSKI; JAMES BALKOVEC

1997-01-01

97

Antisense Oligonucleotides: Insights from Preclinical Studies and Clinical Trials  

Microsoft Academic Search

\\u000a Since the first pioneering studies using antisense oligonucleotides (ASOs) in the late 1970s, thousands of publications followed,\\u000a demonstrating the remarkableness of antisense action and its enormous application spectrum. In 1998, Fomivirsen (Vitravene)\\u000a was the first, and to date the only ASO that gained approval by the US Food and Drug Administration (FDA) for intravitreous\\u000a treatment of cytomegalovirus-induced retinitis in patients

Doreen Kunze; Kai Kraemer; Susanne Fuessel

98

Development of regional chemotherapies: feasibility, safety and efficacy in clinical use and preclinical studies  

PubMed Central

Conventional oral and intravenous chemotherapies permeate throughout the body, exposing healthy tissues to similar cytotoxic drug levels as tumors. This leads to significant dose-limiting toxicities that may prevent patients from receiving sufficient treatment to overcome cancers. Therefore, a number of locoregional drug-delivery strategies have been evaluated and implemented in preclinical studies, clinical trials and in practice, in the past decades to minimize systemic toxicities from chemotherapeutic agents and to improve treatment outcomes. Localized treatment is beneficial because many cancers, such as melanoma, peritoneal cancer and breast cancer, advance locally adjacent to the site of the primary tumors prior to their circulatory invasion. In this article, we will review the feasibility, safety and efficacy of multiple localized chemotherapies in clinical use and preclinical development.

Cai, Shuang; Bagby, Taryn R; Forrest, M Laird

2011-01-01

99

Characterisation of nanoparticle size and concentration for toxicological studies.  

PubMed

The assessment of the complete distribution of nanoparticle sizes within a suspension is notoriously difficult to carry out. We demonstrate the Nanoparticle Tracking Analysis (NTA) technique that sizes nanoparticles in suspension, based on their Brownian motion. This technique has found significant use in the field of nano- and eco-toxicology, in several research groups showing of the technique to assess a range of engineered nanoparticles including gold, SiO2, TiO2 and polystyrene. This capability shares many features in common with conventional flow cytometry but is unique in this deeply sub-micron size range. NTA is a direct and fast technique by which nanoparticles in their natural solvated state in a liquid can be rapidly detected, sized and counted. The technique can be used to complement existing techniques for the sizing of nanoparticles (e.g., DLS, PCS) allowing data obtained from these methods to be validated by direct microscopical observation of the sample. PMID:21485867

Bendre, V; Gautam, M; Carr, R; Smith, J; Malloy, A

2011-02-01

100

New Diet (NTP2000) for Rats in the National Toxicology Program Toxicity and Carcinogenicity Studies  

Microsoft Academic Search

Composition of diet may influence growth, diseases, tumor rates, and responses to chemical treatment. Since 1980 the NIH-07 open formula nonpurified diet has been the selected diet for the National Toxicology Program (NTP) toxicity and carcinogenicity studies in rodents. Studies with nonpurified experimental diets with lower protein and higher fat and fiber than the NIH-07 diet indicated that the diet

Ghanta N. Rao

1996-01-01

101

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

102

SIMPLE, INEXPENSIVE HEART RATE MONITOR AND ARRHYTHMIA DETECTOR FOR USE IN TOXICOLOGICAL STUDIES  

EPA Science Inventory

Many toxic agents have been reported to produce acute, adverse effects on cardiac function. Often these data are neglected in toxicological studies because of the difficulty and expense of monitoring cardiac parameters. We have developed a simple, inexpensive heart rate monitor (...

103

Size Distributions and Characterization of Native and Ground Samples for Toxicology Studies  

NASA Technical Reports Server (NTRS)

This slide presentation shows charts and graphs that review the particle size distribution and characterization of natural and ground samples for toxicology studies. There are graphs which show the volume distribution versus the number distribution for natural occurring dust, jet mill ground dust, and ball mill ground dust.

McKay, David S.; Cooper, Bonnie L.; Taylor, Larry A.

2010-01-01

104

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

105

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

2011-01-01

106

Review: green tea polyphenols in chemoprevention of prostate cancer: preclinical and clinical studies.  

PubMed

The prevention of prostate cancer (PCa) is a crucial medical challenge in developed countries. PCa remains surrounded by puzzles in spite of the considerable progress in research, diagnosis, and treatment. It is an ideal target for chemoprevention, as clinically significant PCa usually requires more than two decades for development. Green tea and its major constituent epigallocatechin gallate (EGCG) have been extensively studied as a potential treatment for a variety of diseases including cancer. In this review, we highlight the evidences of green tea polyphenols from preclinical and clinical studies in the chemoprevention/chemotherapy of PCa. PMID:20155624

Khan, Naghma; Adhami, Vaqar Mustafa; Mukhtar, Hasan

2009-01-01

107

Ultrastructural analysis in preclinical safety evaluation.  

PubMed

The first electron microscopic images of biological specimens were made in the 1940s, and the next 30 years comprised an era of descriptive ultrastructure during which transmission electron microscopy (TEM) was integral to an explosion in cellular and molecular biology. However, when questions could no longer be answered by ultrastructural information alone, the use of TEM in biological research declined. Innovative molecular techniques and newer imaging technologies such as confocal fluorescence microscopy filled the gap, providing faster answers with less rigorous training as a prerequisite to data collection. The use of TEM in toxicologic pathology has paralleled the rise and fall of its popularity in other disciplines. However, TEM remains an essential resource that provides direct and unequivocal data to explain and address safety concerns in preclinical toxicity studies. There is still an important place for TEM in preclinical safety evaluation and mechanistic studies, particularly when visualization of subcellular structures provides a link to other endpoints. This review reinforces the value of TEM in preclinical safety testing and model development and encourages best practices for ultrastructural evaluation. PMID:22215513

Fagerland, Jane A; Wall, Henry G; Pandher, Karamjeet; LeRoy, Bruce E; Gagne, Gerard D

2012-01-01

108

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

109

Targeted agents: how to select the winners in preclinical and early clinical studies?  

PubMed

There has been a significant shift within oncology drug development away from empiric screening of cytotoxic compounds to the era of genomics and molecularly targeted agents. The drug development process is evolving with greater emphasis on proof-of-mechanism studies in both preclinical and early clinical development. The Methodology for the Development of Innovative Cancer Therapies (MDICT) Task Force, established as a forum for academic and pharmaceutical leaders to discuss methodological issues in targeted anticancer therapy development, met in March 2010 to review what were the minimal data required to make appropriate decisions about moving new targeted cancer agents from late preclinical development into phase I and from phase I into phase II trials. A number of specific questions were posed, and responses to each developed through survey, literature review and discussion at the face to face meeting of the MDICT Task Force. Consensus emerged around the necessity to demonstrate proof-of-mechanism and obtain information on key pharmacokinetic aspects of drug behaviour in late preclinical and early clinical trials. However, controversy remains on the extent of in vivo anti-tumour efficacy required to support clinical development of targeted agents. A systematic review of the data in this area would be informative. Further, while objective response in phase I trials may be a favourable signal about the potential activity of a new agent, debate exists around the weight that should be placed on the observation of stable disease or functional imaging changes in driving drug development decisions in the absence of observing either responses or convincing pharmacodynamic data in phase I. MDICT made a number of recommendations that may aid in future development of targeted agents. PMID:22093946

Goodwin, Rachel; Giaccone, Giuseppe; Calvert, Hilary; Lobbezoo, Marinus; Eisenhauer, Elizabeth A

2012-01-01

110

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

111

COMPUTATIONAL TOXICOLOGY  

EPA Science Inventory

Over the last several years, there has been increased pressure to utilize novel technologies derived from computational chemistry, molecular biology and systems biology in toxicological risk assessment. This new area has been referred to as "Computational Toxicology". Our resear...

112

Computational Toxicology  

EPA Science Inventory

?Computational toxicology? is a broad term that encompasses all manner of computer-facilitated informatics, data-mining, and modeling endeavors in relation to toxicology, including exposure modeling, physiologically based pharmacokinetic (PBPK) modeling, dose-response modeling, ...

113

Pegylated liposomal doxorubicin: proof of principle using preclinical animal models and pharmacokinetic studies.  

PubMed

Encapsulation of doxorubicin in polyethylene glycol-coated liposomes (Doxil/Caelyx [PLD]), was developed to enhance the safety and efficacy of conventional doxorubicin. The liposomes alter pharmacologic and pharmacokinetic parameters of conventional doxorubicin so that drug delivery to the tumor is enhanced while toxicity normally associated with conventional doxorubicin is decreased. In animals and humans, pharmacokinetic advantages of PLD include an increased area under the plasma concentration-time curve, longer distribution half-life, smaller volume of distribution, and reduced clearance. In preclinical models, PLD produced remission and cure against many cancers including tumors of the breast, lung, ovaries, prostate, colon, bladder, and pancreas, as well as lymphoma, sarcoma, and myeloma. It was also found to be effective as adjuvant therapy. In addition, it was found to cross the blood-brain barrier and induce remission in tumors of the central nervous system. Increased potency over conventional doxorubicin was observed and, in contrast to conventional doxorubicin, PLD was equally effective against low- and high-growth fraction tumors. The combination of PLD with vincristine or trastuzumab resulted in additive effects and possible synergy. PLD appeared to overcome multidrug resistance, possibly as the result of increased intracellular concentrations and an interaction between the liposome and P-glycoprotein function. On the basis of pharmacokinetic and preclinical studies, PLD, either alone or as part of combination therapy, has potential applications to treat a variety of cancers. PMID:15717736

Vail, David M; Amantea, Michael A; Colbern, Gail T; Martin, Francis J; Hilger, Ralf A; Working, Peter K

2004-12-01

114

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

115

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

116

Bioresorbable fracture fixation in orthopedics: a comprehensive review. Part I. Basic science and preclinical studies.  

PubMed

Metal alloys are currently the most popular materials for manufacture of fracture-fixation devices. Two major disadvantages of these materials are their extreme stiffness, which causes stress shielding of the underlying bone, and the necessity, in a significant number of cases, of removing metallic implants after fracture healing is complete. These shortcomings of metal alloys have led to the study of bioresorbable materials for use in fracture fixation. Currently, polylactic acid, polyglycolic acid, and polydioxanone implants are available to the orthopedic surgeon for the fixation of small cancellous bone fractures. Part I of this article provides an overview of the basic science of bioresorbable materials and presents a comprehensive review of preclinical studies reported in the orthopedic literature. Clinical studies will be reviewed in Part II. PMID:9349887

Simon, J A; Ricci, J L; Di Cesare, P E

1997-10-01

117

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

118

Pig models of neurodegenerative disorders: Utilization in cell replacement-based preclinical safety and efficacy studies.  

PubMed

An important component for successful translation of cell replacement-based therapies into clinical practice is the utilization of large animal models to conduct efficacy and/or safety cell dosing studies. Over the past few decades, several large animal models (dog, cat, nonhuman primate) were developed and employed in cell replacement studies; however, none of these models appears to provide a readily available platform to conduct effective and large-scale preclinical studies. In recent years, numerous pig models of neurodegenerative disorders were developed using both a transgenic approach as well as invasive surgical techniques. The pig model (naïve noninjured animals) was recently used successfully to define the safety and optimal dosing of human spinal stem cells after grafting into the central nervous system (CNS) in immunosuppressed animals. The data from these studies were used in the design of a human clinical protocol used in amyotrophic lateral sclerosis (ALS) patients in a Phase I clinical trial. In addition, a highly inbred (complete major histocompatibility complex [MHC] match) strain of miniature pigs is available which permits the design of comparable MHC combinations between the donor cells and the graft recipient as used in human patients. Jointly, these studies show that the pig model can represent an effective large animal model to be used in preclinical cell replacement modeling. This review summarizes the available pig models of neurodegenerative disorders and the use of some of these models in cell replacement studies. The challenges and potential future directions in more effective use of the pig neurodegenerative models are also discussed. J. Comp. Neurol. 522:2784-2801, 2014. © 2014 Wiley Periodicals, Inc. PMID:24610493

Dolezalova, Dasa; Hruska-Plochan, Marian; Bjarkam, Carsten R; Sørensen, Jens Christian H; Cunningham, Miles; Weingarten, David; Ciacci, Joseph D; Juhas, Stefan; Juhasova, Jana; Motlik, Jan; Hefferan, Michael P; Hazel, Tom; Johe, Karl; Carromeu, Cassiano; Muotri, Alysson; Bui, Jack; Strnadel, Jan; Marsala, Martin

2014-08-15

119

Systematic reviews and meta-analysis of preclinical studies: why perform them and how to appraise them critically  

PubMed Central

The use of systematic review and meta-analysis of preclinical studies has become more common, including those of studies describing the modeling of cerebrovascular diseases. Empirical evidence suggests that too many preclinical experiments lack methodological rigor, and this leads to inflated treatment effects. The aim of this review is to describe the concepts of systematic review and meta-analysis and consider how these tools may be used to provide empirical evidence to spur the field to improve the rigor of the conduct and reporting of preclinical research akin to their use in improving the conduct and reporting of randomized controlled trials in clinical research. As with other research domains, systematic reviews are subject to bias. Therefore, we have also suggested guidance for their conduct, reporting, and critical appraisal.

Sena, Emily S; Currie, Gillian L; McCann, Sarah K; Macleod, Malcolm R; Howells, David W

2014-01-01

120

Spinal cord stimulation for heart failure: preclinical studies to determine optimal stimulation parameters for clinical efficacy.  

PubMed

Spinal cord stimulation with implantable devices has been used worldwide for decades to treat regional pain conditions and cardiac angina refractory to conventional therapies. Preclinical studies with spinal cord stimulation in experimental animal models of heart disease have described interesting effects on cardiac and autonomic nervous system physiology. In canine and porcine animals with failing hearts, spinal cord stimulation reverses left ventricular dilation and improves cardiac function, while suppressing the prevalence of cardiac arrhythmias. In this paper, we present further canine studies that determined the optimal site and intensity of spinal cord stimulation that produced the most robust and beneficial clinical response in heart failure animals. We then explore and discuss the clinically relevant aspects and potential impediments that may be encountered in translating spinal cord stimulation to human patients with advanced cardiac disease. PMID:24569871

Lopshire, John C; Zipes, Douglas P

2014-04-01

121

Behavioral toxicology  

SciTech Connect

The new fields of behavioral toxicology and behavioral teratology investigate the outcome of specific toxic exposures in humans and animals on learning, memory, and behavioral characteristics. Three important classes of behavioral neurotoxicants are metals, solvents, and pesticides. The clearest data on the deleterious effects of prenatal exposure to toxicants comes from the study of two metals, lead and mercury, and form epidemiological investigations of the effects of alcohol taken during pregnancy. Less complete data are available for two other groups of agents, solvents, and pesticides. What we do know about their effects on the fetal brain is convincing enough to make us demand caution in their distribution. 15 refs.

Needleman, H.L. [Univ. of Pittsburgh, PA (United States)

1995-09-01

122

Fabry Disease: Preclinical Studies Demonstrate the Effectiveness of ?-Galactosidase A Replacement in Enzyme-Deficient Mice  

PubMed Central

Preclinical studies of enzyme-replacement therapy for Fabry disease (deficient ?-galactosidase A [?-Gal A] activity) were performed in ?-Gal A–deficient mice. The pharmacokinetics and biodistributions were determined for four recombinant human ?-Gal A glycoforms, which differed in sialic acid and mannose-6-phosphate content. The plasma half-lives of the glycoforms were ?2–5 min, with the more sialylated glycoforms circulating longer. After intravenous doses of 1 or 10 mg/kg body weight were administered, each glycoform was primarily recovered in the liver, with detectable activity in other tissues but not in the brain. Normal or greater activity levels were reconstituted in various tissues after repeated doses (10 mg/kg every other day for eight doses) of the highly sialylated AGA-1 glycoform; 4 d later, enzyme activity was retained in the liver and spleen at levels that were, respectively, 30% and 10% of that recovered 1 h postinjection. Importantly, the globotriaosylceramide (GL-3) substrate was depleted in various tissues and plasma in a dose-dependent manner. A single or repeated doses (every 48 h for eight doses) of AGA-1 at 0.3–10.0 mg/kg cleared hepatic GL-3, whereas higher doses were required for depletion of GL-3 in other tissues. After a single dose of 3 mg/kg, hepatic GL-3 was cleared for ?4 wk, whereas cardiac and splenic GL-3 reaccumulated at 3 wk to ?30% and ?10% of pretreatment levels, respectively. Ultrastructural studies demonstrated reduced GL-3 storage posttreatment. These preclinical animal studies demonstrate the dose-dependent clearance of tissue and plasma GL-3 by administered ?-Gal A, thereby providing the in vivo rationale—and the critical pharmacokinetic and pharmacodynamic data—for the design of enzyme-replacement trials in patients with Fabry disease.

Ioannou, Yiannis A.; Zeidner, Ken M.; Gordon, Ronald E.; Desnick, Robert J.

2001-01-01

123

Exploring Polymeric Micelles for Improved Delivery of Anticancer Agents: Recent Developments in Preclinical Studies  

PubMed Central

As versatile drug delivery systems, polymeric micelles have demonstrated particular strength in solubilizing hydrophobic anticancer drugs while eliminating the use of toxic organic solvents and surfactants. However, the true promise of polymeric micelles as drug carriers for cancer therapy resides in their potential ability to preferentially elevate drug exposure in the tumor and achieve enhanced anticancer efficacy, which still remains to be fully exploited. Here, we review various micellar constructs that exhibit the enhanced permeation and retention effect in the tumor, the targeting ligands that potentiate the anticancer efficacy of micellar drugs, and the polyplex micelle systems suitable for the delivery of plasmid DNA and small interference RNA. Together, these preclinical studies in animal models help us further explore polymeric micelles as emerging drug carriers for targeted cancer therapy.

Tan, Chalet; Wang, Yingzhe; Fan, Wei

2013-01-01

124

Contribution of Large Pig for Renal Ischemia-Reperfusion and Transplantation Studies: The Preclinical Model  

PubMed Central

Animal experimentation is necessary to characterize human diseases and design adequate therapeutic interventions. In renal transplantation research, the limited number of in vitro models involves a crucial role for in vivo models and particularly for the porcine model. Pig and human kidneys are anatomically similar (characterized by multilobular structure in contrast to rodent and dog kidneys unilobular). The human proximity of porcine physiology and immune systems provides a basic knowledge of graft recovery and inflammatory physiopathology through in vivo studies. In addition, pig large body size allows surgical procedures similar to humans, repeated collections of peripheral blood or renal biopsies making pigs ideal for medical training and for the assessment of preclinical technologies. However, its size is also its main drawback implying expensive housing. Nevertheless, pig models are relevant alternatives to primate models, offering promising perspectives with developments of transgenic modulation and marginal donor models facilitating data extrapolation to human conditions.

Giraud, S.; Favreau, F.; Chatauret, N.; Thuillier, R.; Maiga, S.; Hauet, T.

2011-01-01

125

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

2010-03-01

126

Preparation and preclinical pharmacological study on a novel bone imaging agent (99m)Tc-EMIDP.  

PubMed

A novel zoledronic acid (ZL) derivative, 1-hydroxy-2-(2-ethyl-4-methyl-1H-imidazol-1-yl)ethane-1,1-diyldiphosphonic acid (EMIDP), was prepared and labeled with (99)(m)Tc successfully in a high labeling yield and good stability in vitro. The preclinical pharmacological properties of (99)(m)Tc-EMIDP were investigated and compared with (99)(m)Tc-MDP and (99)(m)Tc-ZL. The studies of biodistribution in mice and SPECT bone imaging of the rabbit suggest that (99)(m)Tc-EMIDP has highly selective uptake in the skeletal system and rapid clearance in the soft tissues. The present findings indicate that (99)(m)Tc-EMIDP holds great potential for bone scintigraphy. PMID:20363146

Lin, Jianguo; Luo, Shineng; Chen, Chuanqing; Qiu, Ling; Wang, Yan; Cheng, Wen; Ye, Wanzhong; Xia, Yongmei

2010-09-01

127

Resveratrol: A Review of Pre-clinical Studies for Human Cancer Prevention  

PubMed Central

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 anti-oxidant 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 anti-cancer effects to support its potential as an anticancer agent in human populations.

Athar, Mohammad; Back, Jung Ho; Tang, Xiuwei; Kim, Kwang Ho; Kopelovich, Levy; Bickers, David R.; Kim, Arianna L.

2007-01-01

128

Immune Competency of a Hairless Mouse Strain for Improved Preclinical Studies in Genetically-Engineered Mice  

PubMed Central

Genetically-engineered mouse models (GEMMs) of cancer are of increasing value to preclinical therapeutics. Optical imaging is a cost-effective method of assessing deep-seated tumor growth in GEMMs whose tumors can be encoded to express luminescent or fluorescent reporters, although reporter signal attenuation would be improved if animals were fur-free. In this study, we sought to determine whether hereditable furlessness resulting from a hypomorphic mutation in the Hairless gene would or would not also affect immune competence. By assessment of humoral and cellular immunity of the SKH1 mouse line bearing the hypomorphic Hairless mutation, we determined that blood counts, immunoglobulin levels, and CD4+ and CD8+ T cells were comparable between SKH1 and the C57Bl/6 strain. On examination of T cell subsets, statistically significant differences in naïve T cells (1.7 vs. 3.4 × 105 cells/spleen in SKH1 vs. C57Bl/6, p=0.008) and memory T cells (1.4 vs. 0.13 × 106 cells/spleen in SKH1 vs. C57Bl/6, p=0.008) were detected. However, the numerical differences did not result in altered T cell functional response to antigen re-challenge (keyhole limpet hemocyanin) in a lymph node cell in vitro proliferative assay. Furthermore, interbreeding the SKH1 mouse line to a rhabdomyosarcoma GEMM demonstrated preserved anti-tumor responses of CD56+ Natural Killer cells and CD163+ macrophages, without any differences in tumor pathology. The fur-free GEMM was also especially amenable to multiplex optical imaging. Thus, SKH1 represents an immune competent, fur-free mouse strain which may be of use for interbreeding to other genetically-engineered mouse models of cancer for improved preclinical studies.

Schaffer, Beverly S.; Grayson, Marcia H.; Wortham, Joy M.; Kubicek, Courtney B.; McCleish, Amanda T.; Prajapati, Suresh I.; Nelon, Laura D.; Brady, Michelle M.; Jung, Inkyung; Hosoyama, Tohru; Sarro, Leslea M.; Hanes, Martha A.; Rubin, Brian P.; Michalek, Joel E.; Clifford, Charles B.; Infante, Anthony J.; Keller, Charles

2010-01-01

129

Preclinical testing on insects predicts human haematotoxic potentials.  

PubMed

The substitution of insects for laboratory animals in toxicity testing is likely to become a reality in the framework of prescreening. Haematotoxicological studies of newly developed chemicals, such as food components, drugs, etc. performed on insects can offer advantages in, for example, environmental toxicology. Reliable routine predictions should produce an increase in our knowledge of haemocyte physiology. Although the differences between human physiology and morphology and those of insects are great, the basic functions of insect haemocytes and mammalian leukocytes appear not to have changed during evolution. The use of insects in haematotoxicity assays represents a preclinical testing strategy which will lower costs, accelerate screening and offer ethical benefits. PMID:19505933

Berger, Josef

2009-10-01

130

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

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies were conducted by administering quercetin to groups of 70 male and 70 female rats at concentrations of 0, 1,000, 10,000 or 40,000 parts per million (ppm) quercetin in feed. Under the conditions of these 2-yea...

1992-01-01

131

Toxicology and Carcinogenesis Studies of Chrysotile Asbestos (Cas No. 12001-29-5) in F344/N Rats (Feed Studies).  

National Technical Information Service (NTIS)

Lifetime toxicology and carcinogenesis studies of short-range (SR) and intermediate-range (IR) fiber length chrysotile asbestos were conducted in groups of 88-250 male and female F344/N rats. Both forms of asbestos were administered at a concentration of ...

1985-01-01

132

Neurodevelopmental toxicology.  

PubMed

The fields of neurotoxicology and developmental toxicology are exploding in research and interest. Much of the data currently known are from epidemiologic human studies or studies of animal models. Each of these modes is difficult to translate to individual clinical encounters. It is often difficult to state with certainty which of the numerous chemical or physical agents in our environment are neurotoxic. Basic scientists will help with advances in molecular biology and toxicology. Improved clinical understanding of these issues may help patients to understand the medical issues; allay feelings of anxiety, guilt, or fear; and avoid unnecessary testing. For exposures that manifest as threshold phenomena, such as lead, the risk to society is even greater than to an individual. Individual risk may be less of a concern than the population's risk because small elevations in the average BLL can cause profound shifts in the normative curve of intelligence, increasing the burden on our institutions and bankrupting the brain trust. Good scholarship and interpersonal judgement are vital when counseling patients on the potential consequences of chemical exposures and are no less important when making policy. The challenge for the clinician reading the research is to remain aware of the limitations and biases of our science. PMID:15757787

Schmid, Carrie; Rotenberg, Joshua S

2005-05-01

133

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...

134

Nonindustry-Sponsored Preclinical Studies on Statins Yield Greater Efficacy Estimates Than Industry-Sponsored Studies: A Meta-Analysis  

PubMed Central

Industry-sponsored clinical drug studies are associated with publication of outcomes that favor the sponsor, even when controlling for potential bias in the methods used. However, the influence of sponsorship bias has not been examined in preclinical animal studies. We performed a meta-analysis of preclinical statin studies to determine whether industry sponsorship is associated with either increased effect sizes of efficacy outcomes and/or risks of bias in a cohort of published preclinical statin studies. We searched Medline (January 1966–April 2012) and identified 63 studies evaluating the effects of statins on atherosclerosis outcomes in animals. Two coders independently extracted study design criteria aimed at reducing bias, results for all relevant outcomes, sponsorship source, and investigator financial ties. The I2 statistic was used to examine heterogeneity. We calculated the standardized mean difference (SMD) for each outcome and pooled data across studies to estimate the pooled average SMD using random effects models. In a priori subgroup analyses, we assessed statin efficacy by outcome measured, sponsorship source, presence or absence of financial conflict information, use of an optimal time window for outcome assessment, accounting for all animals, inclusion criteria, blinding, and randomization. The effect of statins was significantly larger for studies sponsored by nonindustry sources (?1.99; 95% CI ?2.68, ?1.31) versus studies sponsored by industry (?0.73; 95% CI ?1.00, ?0.47) (p value<0.001). Statin efficacy did not differ by disclosure of financial conflict information, use of an optimal time window for outcome assessment, accounting for all animals, inclusion criteria, blinding, and randomization. Possible reasons for the differences between nonindustry- and industry-sponsored studies, such as selective reporting of outcomes, require further study.

Krauth, David; Anglemyer, Andrew; Philipps, Rose; Bero, Lisa

2014-01-01

135

IN VITRO STUDIES: WHAT IS THEIR ROLE IN TOXICOLOGY?  

EPA Science Inventory

Many epidemiology studies have reported associations between inhaled environmental pollutants, especially particles, and mortality or morbidity. Despite these impressive associations, fundamental uncertainties exist as to the underlying pathophysiological mechanisms responsible f...

136

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...

137

Toxicology Studies with Beta-Thioguanine Deoxyriboside (Nsc-71261).  

National Technical Information Service (NTIS)

The amount of thioguanine deoxyriboside which can be administered to mice as a single dose is approximately four times the total dose that can be administered on a five day repeated schedule. In single dose mouse studies, males tolerated more than females...

R. E. Morrison, D. E. Brown, E. K. Timmens, D. A. Cooney, R. A. Davis

1969-01-01

138

Environmental fate and aquatic toxicology studies on phthalate esters  

Microsoft Academic Search

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

E. F. Jr

1986-01-01

139

Cassava starch fermentation wastewater: Characterization and preliminary toxicological studies  

Microsoft Academic Search

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 5g\\/kg\\/body weight did

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

2007-01-01

140

Comparative Inhalation Toxicology of Selected Materials. Phase 3 Studies.  

National Technical Information Service (NTIS)

A subchronic inhalation study of powdered Cu-Zn alloy (Cu-Zn) was conducted with F344/N rats. Exposures were 1.5 hours/day, 4 days/week to 0, 0.32, 1.0, 3.2, or 10 mg Cu-Zn/m3 for 13 weeks, followed by a 4-Week recovery period. Rats were exposed nose-only...

A. F. Eidson D. E. Bice D. G. Burt E. G. Damon M. B. Snipes

1988-01-01

141

Pharmaco-toxicological study of Kageneckia oblonga, Rosaceae.  

PubMed

The probable antipyretic, antiinflammatory, analgesic and antioxidant properties of Kageneckia oblonga, Rosaceae, were investigated and the major compounds of its active extracts were isolated. The study comprised the acute toxicity of the extracts of global methanol, hexane, dichloromethane and methanol. The cytotoxicity of global methanol extract was studied in three tumoral cell lines. All the extracts exhibited the pharmacological activities under study. Methanol and dichloromethane were the most toxic extracts. From the global methanol extract, isolations were performed of prunasin, 23,24- dihydro-cucurbitacin F, and a new cucurbitacin, 3beta-(beta-D-glucosyloxy)-16alpha,23alpha-epoxycucurbita-5,24-diene-11-one. The cytotoxicity of both cucurbitacins on human neutrophils at the assayed concentrations was not statistically significant. In-vitro assays showed that both cucurbitacins can be partly responsible for the analgesic, antipyretic, and anti-inflammatory activities. Evaluation was done of the cytotoxicity of global methanol extract, 23, 24-dihydrocucurbitacin F, aqueous extracts and prunasin against P-388 murine leukaemia, A-549 human lung carcinoma and HT-29 colon carcinoma. Since global methanol extract presented a strong cytotoxicity against P-388 murine leukaemia, A-549 human lung carcinoma, and HT-29 cell lines, it is highly probable that this extract contain one or more cytotoxic compounds that could be investigated for their potential use as an agent against cancer. PMID:11926521

Delporte, Carla; Muñoz, Orlando; Rojas, Javier; Ferrándiz, Marisa; Payá, Miguel; Erazo, Silvia; Negrete, Rosa; Maldonado, Sergio; San, Feliciano Arturo; Backhouse, Nadine

2002-01-01

142

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

143

Techniques for pharmacological and toxicological studies with isolated hepatocyte suspensions  

SciTech Connect

The isolated hepatocyte preparation is particularly convenient for the study of the kinetics of hepatic drug uptake and excretion because the cells can be rapidly separated from the incubation medium. Isolated liver cells have also proved valuable for investigating drug metabolism since they show many of the features of the intact liver. However, they also show important differences such as losses of membrane specialization, some degree of cell polarity and the capacity to form bile. The many consequences of the hepatic toxicity of xenobiotics including lipid peroxidation, free radical formation, glutathione depletion, and covalent binding to macromolecules are also readily studied with the isolated liver cell preparation. A particular advantage is the ease with which morphological changes as a result of drug exposure can be observed in isolated hepatocytes. However, it must be remembered that the isolation procedure inevitably introduces changes that may make the cells more susceptible than the normal liver to damage by xenobiotic agents. Despite its limitations, the isolated hepatocyte preparation is now firmly established in the armamentarium of the investigator examining the interaction of the liver with xenobiotics. 237 refs.

Berry, M.N.; Halls, H.J.; Grivell, M.B. (Flinders Univ. of South Australia, Adelaide (Australia))

1992-01-01

144

Some pharmacological and toxicological studies on Balanites aegyptiaca bark.  

PubMed

The aqueous extract of Balanites aegyptiaca bark, which is used in Sudanese folk medicine in the treatment of jaundice, was without effect when studied on rabbit intestine, rabbit aortic strip, rat stomach strip, rat uterus and rat phrenic nerve-diaphragm in a dose up to 10 mg/mL gut bath. In a larger dose (25 mg) the extract decreased significantly the contractility and the rate of the isolated perfused rabbit heart. Administration of the aqueous extract to biliary duct-ligated rats, showed a dose-dependent significant decrease in serum bilirubin level. The chronic and subchronic toxicity investigations indicate the safety of the aqueous extract at a dose level which showed a significant decrease in serum bilirubin level in experimental obstructive jaundice in rats. PMID:10441790

Mohamed, A H; Eltahir, K E; Ali, M B; Galal, M; Ayeed, I A; Adam, S I; Hamid, O A

1999-08-01

145

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

146

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

147

Arsenite cocarcinogenesis: an animal model derived from genetic toxicology studies.  

PubMed Central

Although epidemiologic evidence shows an association between inorganic arsenic in drinking water and increased risk of skin, lung, and bladder cancers, no animal model for arsenic carcinogenesis has been successful. This lack has hindered mechanistic studies of arsenic carcinogenesis. Previously, we and others found that low concentrations (< or =5 microm) of arsenite (the likely environmental carcinogen), which are not mutagenic, can enhance the mutagenicity of other agents, including ultraviolet radiation (UVR) and alkylating agents. This enhancing effect appears to result from inhibition of DNA repair by arsenite, but not via inhibition of DNA repair enzymes. Rather, low concentrations of arsenite disrupt p53 function and upregulate cyclin D1. Failure to find an animal model for arsenic carcinogenesis might be because arsenite is not a carcinogen per se but acts as an enhancing agent (cocarcinogen) with a genotoxic partner. We tested this hypothesis with solar UVR in hairless but immunocompetent Skh1 mice. Mice were given 10 mg/L sodium arsenite in drinking water (or not) and irradiated with 1.7 KJ/m(2) solar UVR 3 times weekly. As expected, no tumors appeared in any organs in control mice or in mice given arsenite alone. After 26 weeks irradiated mice given arsenite had a 2.4-fold increase in skin tumor yield compared with mice given UVR alone. The tumors were mostly squamous cell carcinomas, and those occurring in mice given UVR plus arsenite were much larger and more invasive. These results are consistent with the hypothesis that arsenic acts as a cocarcinogen with a second (genotoxic) agent by inhibiting DNA repair and/or enhancing positive growth signaling. Skin cancers in populations drinking water containing arsenic may be caused by the enhancement by arsenic compounds of carcinogenesis induced by UVR (or other environmental agents). It is possible that lung and bladder cancers associated with arsenic in drinking water may also require a carcinogenic partner.

Rossman, Toby G; Uddin, Ahmed N; Burns, Fredric J; Bosland, Maarten C

2002-01-01

148

CCD-camera-based diffuse optical tomography to study ischemic stroke in preclinical rat models  

NASA Astrophysics Data System (ADS)

Stroke, due to ischemia or hemorrhage, is the neurological deficit of cerebrovasculature and is the third leading cause of death in the United States. More than 80 percent of stroke patients are ischemic stroke due to blockage of artery in the brain by thrombosis or arterial embolism. Hence, development of an imaging technique to image or monitor the cerebral ischemia and effect of anti-stoke therapy is more than necessary. Near infrared (NIR) optical tomographic technique has a great potential to be utilized as a non-invasive image tool (due to its low cost and portability) to image the embedded abnormal tissue, such as a dysfunctional area caused by ischemia. Moreover, NIR tomographic techniques have been successively demonstrated in the studies of cerebro-vascular hemodynamics and brain injury. As compared to a fiberbased diffuse optical tomographic system, a CCD-camera-based system is more suitable for pre-clinical animal studies due to its simpler setup and lower cost. In this study, we have utilized the CCD-camera-based technique to image the embedded inclusions based on tissue-phantom experimental data. Then, we are able to obtain good reconstructed images by two recently developed algorithms: (1) depth compensation algorithm (DCA) and (2) globally convergent method (GCM). In this study, we will demonstrate the volumetric tomographic reconstructed results taken from tissuephantom; the latter has a great potential to determine and monitor the effect of anti-stroke therapies.

Lin, Zi-Jing; Niu, Haijing; Liu, Yueming; Su, Jianzhong; Liu, Hanli

2011-02-01

149

"1. M Indira MA Andrews TP Lakesh. Incidence predictors and outcome of intermediate syndrome in cholinergic insecticide poisoning: a prospective observational cohort study. Clinical Toxicology"  

EPA Pesticide Factsheets

Did you mean: "1. M Indira MA Andrews TP Lakesh. Incidence predictors and outcome of intermediate syndrome in cholinergic insecticide poisoning: a prospective observational cohort study. Clinical Toxicology" ?

150

Preclinical Toxicologic Studies of L-Alanosine (NSC 153353) and DL-Alanosine (NSC 143647) in Beagle Dogs.  

National Technical Information Service (NTIS)

Responses to both drugs were qualitatively similar with L-Alanosine inducing slightly greater toxicity in dogs, while the LD10, LD50, and LD90 in mice were achieved at lower dosage levels with D,L-Alanosine. D,L-Alanosine (NSC 143647) and L,Alanosine (NSC...

D. C. Thake M. W. Naylor R. H. Denlinger A. M. Guarino C. L. Litterest

1976-01-01

151

Dried blood spot sampling: practical considerations and recommendation for use with preclinical studies.  

PubMed

At present it is necessary to use animals to generate toxicokinetic data as part of preclinical safety studies. However, ethical standards require animal use to be carefully monitored and the principles of the 3Rs: replacement, reduction and refinement, to be considered and applied. Use of dried blood spot (DBS) samples, typically 10 to 20 µl, rather than the larger blood volumes required to obtain plasma samples, fully embraces the latter two principles of reduction and refinement. The use of DBS sampling enables the number of rodents per study to be reduced whilst also refining the way blood samples are taken from both rodents and non-rodents. The recent changes to the European Directive on the protection of animals used for scientific purposes favor DBS sampling becoming the standard for generation of toxicokinetic data, and imply that pharmaceutical companies will have to justify why plasma samples (and therefore larger blood volumes) are required for bioanalysis. Use of DBS samples has been, and is being, discussed widely within the pharmaceutical industry as the move away from taking large blood volumes becomes inevitable. PMID:21585305

Burnett, Josephine Ec

2011-05-01

152

Toxicology of antisense therapeutics.  

PubMed

Targeting unique mRNA molecules using antisense approaches, based on sequence specificity of double-stranded nucleic acid interactions should, in theory, allow for design of drugs with high specificity for intended targets. Antisense-induced degradation or inhibition of translation of a target mRNA is potentially capable of inhibiting the expression of any target protein. In fact, a large number of proteins of widely varied character have been successfully downregulated using an assortment of antisense-based approaches. The most prevalent approach has been to use antisense oligonucleotides (ASOs), which have progressed through the preclinical development stages including pharmacokinetics and toxicological studies. A small number of ASOs are currently in human clinical trials. These trials have highlighted several toxicities that are attributable to the chemical structure of the ASOs, and not to the particular ASO or target mRNA sequence. These include mild thrombocytopenia and hyperglycemia, activation of the complement and coagulation cascades, and hypotension. Dose-limiting toxicities have been related to hepatocellular degeneration leading to decreased levels of albumin and cholesterol. Despite these toxicities, which are generally mild and readily treatable with available standard medications, the clinical trials have clearly shown that ASOs can be safely administered to patients. Alternative chemistries of ASOs are also being pursued by many investigators to improve specificity and antisense efficacy and to reduce toxicity. In the design of ASOs for anticancer therapeutics in particular, the goal is often to enhance the cytotoxicity of traditional drugs toward cancer cells or to reduce the toxicity to normal cells to improve the therapeutic index of existing clinically relevant cancer chemotherapy drugs. We predict that use of antisense ASOs in combination with small molecule therapeutics against the target protein encoded by the antisense-targeted mRNA, or an alternate target in the same or a connected biological pathway, will likely be the most beneficial application of this emerging class of therapeutic agent. PMID:15519609

Jason, Tracey L H; Koropatnick, James; Berg, Randal W

2004-11-15

153

A novel bone conduction implant (BCI): engineering aspects and pre-clinical studies.  

PubMed

Percutaneous bone anchored hearing aids (BAHA) are today an important rehabilitation alternative for patients suffering from conductive or mixed hearing loss. Despite their success they are associated with drawbacks such as skin infections, accidental or spontaneous loss of the bone implant, and patient refusal for treatment due to stigma. A novel bone conduction implant (BCI) system has been proposed as an alternative to the BAHA system because it leaves the skin intact. Such a BCI system has now been developed and the encapsulated transducer uses a non-screw attachment to a hollow recess of the lateral portion of the temporal bone. The aim of this study is to describe the basic engineering principals and some preclinical results obtained with the new BCI system. Laser Doppler vibrometer measurements on three cadaver heads show that the new BCI system produces 0-10 dB higher maximum output acceleration level at the ipsilateral promontory relative to conventional ear-level BAHA at speech frequencies. At the contralateral promontory the maximum output acceleration level was considerably lower for the BCI than for the BAHA. PMID:20105095

Håkansson, Bo; Reinfeldt, Sabine; Eeg-Olofsson, Måns; Ostli, Per; Taghavi, Hamidreza; Adler, Johannes; Gabrielsson, John; Stenfelt, Stefan; Granström, Gösta

2010-03-01

154

Preclinical studies of a specific PPAR? modulator in the control of skin inflammation.  

PubMed

Peroxisome proliferator-activated receptor ? (PPAR?) antagonizes inflammatory signals by interfering with NF-?B nuclear translocation. Consistently, PPAR? agonists have been proposed in various inflammatory skin disorders, but their wide use has been limited by severe side effects. Classes of compounds with specific PPAR? agonism have been designed to selectively target inflammatory pathways. Among these compounds, GED-0507-34L has been developed and recently used in phase II clinical trials for inflammatory bowel diseases. This study was aimed at assessing the role of GED-0507-34L in preclinical models of inflammatory skin diseases. The compound modulated PPAR? function and suppressed the inflammatory process inhibiting NF-?B nuclear translocation with the consequent reduction of inflammatory cytokines expression, such as IL-6, IL-8, IL-12, IL-21, IL-23, tumor necrosis factor-? (TNF-?), and cyclooxygenase-2 (COX-2) in normal human keratinocytes and lymphocytes treated with lipopolysaccharide (LPS) or TNF-?. Moreover, an altered proliferation and expression of differentiation markers induced by TNF-? were also counteracted. In psoriasis-like skin lesions elicited in mice by IL-21, topical application of GED-0507-34L reduced cellular infiltrate and epidermal hyperplasia, normalizing the differentiation process. The results indicate that GED-0507-34L possesses anti-inflammatory properties useful for the management of patients with inflammatory skin diseases including psoriasis. Phase I trial on patients is ongoing. PMID:24166135

Mastrofrancesco, Arianna; Kovacs, Daniela; Sarra, Massimiliano; Bastonini, Emanuela; Cardinali, Giorgia; Aspite, Nicaela; Camera, Emanuela; Chavatte, Philippe; Desreumaux, Pierre; Monteleone, Giovanni; Picardo, Mauro

2014-04-01

155

Stem cell therapy for ischaemic stroke: translation from preclinical studies to clinical treatment.  

PubMed

No pharmacological intervention has been shown convincingly to improve neurological outcome in stroke patients after the brain tissue is infarcted. While conventional therapeutic strategies focus on preventing brain damage, stem cell treatment has the potential to repair the injured brain tissue. Stem cells not only produce a source of trophic molecules to minimize brain damage caused by ischaemia/reperfusion and promote recovery, but also potentially turn to new cells to replace those lost in ischaemic core. Although preclinical studies have shown promise, stem cell therapy for stroke treatment in human is still at an early stage and it is difficult to draw conclusions from current clinical trials about the efficacy of the different treatments used in humans. This article reviews the potential of various types of stem cells, from embryonic to adult to induced pluripotent stem cells, in stroke therapy, highlights new evidence from the ongoing clinical trials and discusses some of the problems associated with translating stem cell technology to a clinical therapy for stroke. PMID:23394533

Balami, Joyce S; Fricker, Rosemary A; Chen, Ruoli

2013-03-01

156

Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) in Preclinical Studies of Antivascular Treatments  

PubMed Central

Antivascular treatments can either be antiangiogenic or targeting established tumour vasculature. These treatments affect the tumour microvasculature and microenvironment but may not change clinical measures like tumour volume and growth. In research on antivascular treatments, information on the tumour vasculature is therefore essential. Preclinical research is often used for optimization of antivascular drugs alone or in combined treatments. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is an in vivo imaging method providing vascular information, which has become an important tool in both preclinical and clinical research. This review discusses common DCE-MRI imaging protocols and analysis methods and provides an overview of preclinical research on antivascular treatments utilizing DCE-MRI.

Nielsen, Thomas; Wittenborn, Thomas; Horsman, Michael R.

2012-01-01

157

Preclinical pharmacology of alendronate  

Microsoft Academic Search

This brief review summarizes some of the preclinical findings of studies aimed at assessing the efficacy and safety of the aminobisphosphonate alendronate (ALN) in preventing or restoring the bone loss caused by calcium or estrogen deficiency. Mode of action studies show that ALN localizes at sites of bone resorption and inhibits osteoclastic activity. In secondary hyperparathyroidism caused by calcium-deficient diets

G. A. Rodan; J. G. Seedor; R. Balena

1993-01-01

158

Evaluation and identification of reliable reference genes for toxicological study in Caenorhabditis elegans.  

PubMed

To identify reliable reference genes for toxicological studies, 16 commonly-used reference genes were selected as candidates to evaluate their expression stabilities under experimental conditions in Caenorhabditis elegans. Sixteen candidates were composed of 12 protein-coding genes and 4 non-coding RNAs, they were act-2, ama-1, arp-6, cdc-42, csq-1, eif-3.C, idhg-1, mdh, pmp-3, rbd-1, tba-1, Y45F10D.4, 18S rRNA, Ce234, U18, and U6. Larval stage 1 synchronized hermaphrodites were exposed to benzo-?-pyrene (B?P), chlorpyrifos, diazinon, gossypol, zinc oxide nanoparticles, and the vehicle control DMSO for 30 h, respectively. Expression stabilities of candidate genes were analyzed using 4 independent evaluating approaches (BestKeeper, the delta Ct approach, geNorm, and NormFinder) followed by a comprehensive method. Results showed that there were slight differences in ranking order between evaluation methods due to their different assumptions and computations. The results also showed that responses of candidate genes to different chemicals were distinct, 18S rRNA was the best for B?P and chlorpyrifos, tba-1 was the most stable gene for diazinon and gossypol treatments, while pmp-3 was more stable for zinc oxide exposure. Additionally, results demonstrated that combinations of multiple genes were more reliable than individual gene, suggesting selecting two or more candidates as reference genes may generate more reliable results for toxicological studies. PMID:24510408

Wu, Hongmei; Taki, Faten A; Zhang, Yanqiong; Dobbins, Dorothy L; Pan, Xiaoping

2014-05-01

159

Pharmacological Intervention Studies Using Mouse Models of the Inflammatory Bowel Diseases: Translating Preclinical Data into New Drug Therapies  

PubMed Central

Most therapeutic agents used in clinical practice today were originally developed and tested in animal models so that drug toxicity and safety, dose-responses and efficacy could be determined. Retrospective analyses of preclinical intervention studies using animal models of different diseases demonstrate that only a small percentage of the interventions reporting promising effects translate to clinical efficacy. The failure to translate therapeutic efficacy from bench to bedside may be due, in part, to shortcomings in the design of the clinical studies; however, it is becoming clear that much of the problem resides within the preclinical studies. One potential strategy for improving our ability to identify new therapeutics that may have a reasonable chance of success in well-controlled clinical trials is to identify the most relevant mouse models IBD and pharmacologic strategies that most closely mimic the clinical situation. To begin this process, we present a critical evaluation of the different mouse models and pharmacological approaches that may be used in intervention studies as well as discuss emerging issues related to study design and data interpretation of preclinical studies.

Koboziev, Iurii; Karlsson, Fridrik; Zhang, Songlin; Grisham, Matthew B.

2010-01-01

160

A comparative toxicological study of Rasamanikya prepared with three different methods  

PubMed Central

Rasamanikya a familiar drug, frequently used by Ayurvedic physicians. It also has a high demand in current pharmaceutical industry. Rasamanikya possesses different pharmaceutical methods with many a proved clinical studies. But it is of utmost importance to understand the safety profile of drug based on assurance which could be done by carrying out animal experimentation. In the present study, Rasamanikya was prepared with three methods. The toxicological study was carried out on acute and sub-acute toxicity of the drug. The three samples when compared together showed that Rasamanikya prepared out of classical Abhraka Patra method and modified Sharava Samputa method showed minimal histopathological changes proving its non-toxicity, whereas Rasamanikya prepared out of electric bulb method showed mild toxicity, but with chances of recovery. Acute toxicity study showed no immediate and evident toxic signs and mortality in histopathology reports and liver function test. However, sub-acute toxicity study showed mild to moderate fatty changes in liver.

Sud, Sushant; Reddy, P. Sekhar; Sujatha, K.; Honwad, Sudheendra

2013-01-01

161

Preclinical potency and safety studies of an AAV2-mediated gene therapy vector for the treatment of MERTK associated retinitis pigmentosa.  

PubMed

Abstract Proof of concept for MERTK gene replacement therapy has been demonstrated using different viral vectors in the Royal College of Surgeon (RCS) rat, a well characterized model of recessive retinitis pigmentosa that contains a mutation in the Mertk gene. MERTK plays a key role in renewal of photoreceptor outer segments (OS) by phagocytosis of shed OS tips. Mutations in MERTK cause impaired phagocytic activity and accumulation of OS debris in the interphotoreceptor space that ultimately leads to photoreceptor cell death. In the present study, we conducted a series of preclinical potency and GLP-compliant safety evaluations of an adeno-associated virus type 2 (AAV2) vector expressing human MERTK cDNA driven by the retinal pigment epithelium-specific, VMD2 promoter. We demonstrate the potency of the vector in RCS rats by improved electroretinogram (ERG) responses in treated eyes compared with contralateral untreated controls. Toxicology and biodistribution studies were performed in Sprague-Dawley (SD) rats injected with two different doses of AAV vectors and buffer control. Delivery of vector in SD rats did not result in a change in ERG amplitudes of rod and cone responses relative to balanced salt solution control-injected eyes, indicating that administration of AAV vector did not adversely affect normal retinal function. In vivo fundoscopic analysis and postmortem retinal morphology of the vector-injected eyes were normal compared with controls. Evaluation of blood smears showed the lack of transformed cells in the treated eyes. All injected eyes and day 1 blood samples were positive for vector genomes, and all peripheral tissues were negative. Our results demonstrate the potency and safety of the AAV2-VMD2-hMERTK vector in animal models tested. A GMP vector has been manufactured and is presently in clinical trial. PMID:23692380

Conlon, Thomas J; Deng, Wen-Tao; Erger, Kirsten; Cossette, Travis; Pang, Ji-jing; Ryals, Renee; Clément, Nathalie; Cleaver, Brian; McDoom, Issam; Boye, Shannon E; Peden, Marc C; Sherwood, Mark B; Abernathy, Corinne R; Alkuraya, Fowzan S; Boye, Sanford L; Hauswirth, William W

2013-03-01

162

Preclinical Potency and Safety Studies of an AAV2-Mediated Gene Therapy Vector for the Treatment of MERTK Associated Retinitis Pigmentosa  

PubMed Central

Abstract Proof of concept for MERTK gene replacement therapy has been demonstrated using different viral vectors in the Royal College of Surgeon (RCS) rat, a well characterized model of recessive retinitis pigmentosa that contains a mutation in the Mertk gene. MERTK plays a key role in renewal of photoreceptor outer segments (OS) by phagocytosis of shed OS tips. Mutations in MERTK cause impaired phagocytic activity and accumulation of OS debris in the interphotoreceptor space that ultimately leads to photoreceptor cell death. In the present study, we conducted a series of preclinical potency and GLP-compliant safety evaluations of an adeno-associated virus type 2 (AAV2) vector expressing human MERTK cDNA driven by the retinal pigment epithelium–specific, VMD2 promoter. We demonstrate the potency of the vector in RCS rats by improved electroretinogram (ERG) responses in treated eyes compared with contralateral untreated controls. Toxicology and biodistribution studies were performed in Sprague–Dawley (SD) rats injected with two different doses of AAV vectors and buffer control. Delivery of vector in SD rats did not result in a change in ERG amplitudes of rod and cone responses relative to balanced salt solution control–injected eyes, indicating that administration of AAV vector did not adversely affect normal retinal function. In vivo fundoscopic analysis and postmortem retinal morphology of the vector-injected eyes were normal compared with controls. Evaluation of blood smears showed the lack of transformed cells in the treated eyes. All injected eyes and day 1 blood samples were positive for vector genomes, and all peripheral tissues were negative. Our results demonstrate the potency and safety of the AAV2-VMD2-hMERTK vector in animal models tested. A GMP vector has been manufactured and is presently in clinical trial.

Deng, Wen-Tao; Erger, Kirsten; Cossette, Travis; Pang, Ji-jing; Ryals, Renee; Clement, Nathalie; Cleaver, Brian; McDoom, Issam; Boye, Shannon E.; Peden, Marc C.; Sherwood, Mark B.; Abernathy, Corinne R.; Alkuraya, Fowzan S.; Boye, Sanford L.; Hauswirth, William W.

2013-01-01

163

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

164

Sex differences in the vulnerability to drug abuse: a review of preclinical studies  

Microsoft Academic Search

Clinical and preclinical findings indicate that males and females differ on several aspects of drug reinforcement. Females are more vulnerable than males during transition periods of drug use that are characteristic of drug addiction and relapse. Females are also more sensitive than males to the reinforcing effects of stimulants. It has been suggested that ovarian hormones contribute to the mechanisms

Megan E. Roth; Kelly P. Cosgrove; Marilyn E. Carroll

2004-01-01

165

Combined effects of bevacizumab with erlotinib and irradiation: a preclinical study on a head and neck cancer orthotopic model  

Microsoft Academic Search

Clinical benefit has been demonstrated in patients with head and neck tumours receiving an anti-epidermal growth factor receptor (EGFR) agent in combination with radiotherapy (RT). Recent preclinical and clinical studies suggest beneficial effects from combining anti-angiogenic drugs with RT. To investigate the effect of combining these approaches, we evaluated in vivo the anti-tumour efficacy of the anti-angiogenic compound bevacizumab, a

A Bozec; A Sudaka; J-L Fischel; M-C Brunstein; M-C Etienne-Grimaldi; G Milano

2008-01-01

166

Spaceflight Toxicology  

NASA Technical Reports Server (NTRS)

This viewgraph presentation provides a review of NASA Johnson Space Center's Toxicology program. The mission of this program is to protect crews from toxic exposures during spaceflight. The presentation reviews some of the health hazards. A toxicological hazard level chart is presented that reviews the rating of hazard level, irritancy, systemic effects and containability. The program also participates in the Lunar Airborne Dust Toxicity Advisory Group.

Meyers, Valerie

2008-01-01

167

Glycoengineered Pichia produced anti-HER2 is comparable to trastuzumab in preclinical study  

PubMed Central

Mammalian cell culture systems are used predominantly for the production of therapeutic monoclonal antibody (mAb) products. A number of alternative platforms, such as Pichia engineered with a humanized N-linked glycosylation pathway, have recently been developed for the production of mAbs. The glycosylation profiles of mAbs produced in glycoengineered Pichia are similar to those of mAbs produced in mammalian systems. This report presents for the first time the comprehensive characterization of an anti-human epidermal growth factor receptor 2 (HER2) mAb produced in glycoengineered Pichia, and a study comparing the anti-HER2 from Pichia, which had an amino acid sequence identical to trastuzumab, with trastuzumab. The comparative study covered a full spectrum of preclinical evaluation, including bioanalytical characterization, in vitro biological functions, in vivo anti-tumor efficacy and pharmacokinetics in both mice and non-human primates. Cell signaling and proliferation assays showed that anti-HER2 from Pichia had antagonist activities comparable to trastuzumab. However, Pichia-produced material showed a 5-fold increase in binding affinity to Fc?IIIA and significantly enhanced antibody dependent cell-mediated cytotoxicity (ADCC) activity, presumably due to the lack of fucose on N-glycans. In a breast cancer xenograft mouse model, anti-HER2 was comparable to trastuzumab in tumor growth inhibition. Furthermore, comparable pharmacokinetic profiles were observed for anti-HER2 and trastuzumab in both mice and cynomolgus monkeys. We conclude that glycoengineered Pichia provides an alternative production platform for therapeutic mAbs and may be of particular interest for production of antibodies for which ADCC is part of the clinical mechanism of action.

Zhang, Ningyan; Liu, Liming; Dumitru, Calin Dan; Cummings, Nga Rewa Houston; Cukan, Michael; Jiang, Youwei; Li, Yuan; Li, Fang; Mitchell, Teresa; Mallem, Muralidhar R; Ou, Yangsi; Patel, Rohan N; Vo, Kim; Wang, Hui; Burnina, Irina; Choi, Byung-Kwon; Huber, Hans; Stadheim, Terrance A

2011-01-01

168

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

169

Toxicology and Carcinogenesis Studies of Hydrochlorothiazide (CAS No. 58-93-5) in F344/N Rats and B6C3Fl Mice (Feed Studies).  

National Technical Information Service (NTIS)

Hydrochlorothiazide is a diuretic active at the distal convoluted tubule and collecting duct. Toxicology and carcinogenesis studies were conducted by feeding diets containing hydrochlorothiazide (USP grade, greater than 98% pure) to groups of F344/N rats ...

J. R. Bucher

1989-01-01

170

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

171

Chronic allyl chloride poisoning. An epidemiology, clinical, toxicological and neuropathological study.  

PubMed

It was previously reported that chronic exposure to allyl chloride resulted in liver and kidney damage. No neurotoxic effect of allyl chloride had been noticed until two outbreaks of polyneuropathy without liver and kidney dysfunction due to exposure to allyl chloride in China in the early 1970's. Epidemiological and clinical studies done within 1973-1982 revealed that the main risk of industrial exposure to allyl chloride is damage to the peripheral nervous system. Polyneuropathy is thought to be the main clinical manifestation of chronic allyl chloride poisoning. Electroneuromyography is essential and valuable for early diagnosis and biological monitoring. Toxicological and neuropathological studies in rabbits and mice have given the evidence of a pattern of central-peripheral distal axonopathy in peripheral nervous system which has further confirmed the neurotoxicity of allyl chloride found in man. Based on the above results, the maximum allowable concentration of allyl chloride and diagnostic criteria for chronic allyl chloride poisoning are proposed. PMID:3000860

He, F S; Lu, B Q; Zhang, S L; Dong, S W; Yu, A; Wang, B Y

1985-01-01

172

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

2011-10-01

173

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

174

THE CHEMICAL CHARACTERIZATION OF THE TEST ARTICLE USED IN TOXICOLOGICAL STUDIES OF GUM ARABIC (ACACIA SENEGAL (L.) WILLD)  

Microsoft Academic Search

The sample of commercial gum arabic used as the “Test Article” in recent toxicological studies has been characterized chemically. Comparative analytical data, presented for seven other commercial gum arabic samples, and for five specimens of gum collected from authenticated Acacia Senegal trees in several gum producing countries, indicate that the Test Article is a fair, average representative sample of gum

D. M. W. ANDERSON; M. M. E. BRIDGEMAN; J. G. K. FARQUHAR; C. G. A. McNAB

1983-01-01

175

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 ...

176

Modeling of Toxicological Effects of Fire Gases: VI. Further Studies on the Toxicity of Smoke Containing Hydrogen Chloride  

Microsoft Academic Search

Studies of rodent lethality due to exposure to HCl, as well as to mixtures of HCl and CO, have shown different apparent toxicological effects at low and at high concentrations of HCl. At low concentrations of HCl, sensory irritation causes a decrease in respiratory minute volume, with somewhat slower loading of CO and a delay in incapacitation. This effect is

G. E. Hartzell; A. F. Grand; W. G. Switzer

1987-01-01

177

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

178

Quantitative approaches for assessing dose-response relationships in genetic toxicology studies.  

PubMed

Genetic toxicology studies are required for the safety assessment of chemicals. Data from these studies have historically been interpreted in a qualitative, dichotomous "yes" or "no" manner without analysis of dose-response relationships. This article is based upon the work of an international multi-sector group that examined how quantitative dose-response relationships for in vitro and in vivo genetic toxicology data might be used to improve human risk assessment. The group examined three quantitative approaches for analyzing dose-response curves and deriving point-of-departure (POD) metrics (i.e., the no-observed-genotoxic-effect-level (NOGEL), the threshold effect level (Td), and the benchmark dose (BMD)), using data for the induction of micronuclei and gene mutations by methyl methanesulfonate or ethyl methanesulfonate in vitro and in vivo. These results suggest that the POD descriptors obtained using the different approaches are within the same order of magnitude, with more variability observed for the in vivo assays. The different approaches were found to be complementary as each has advantages and limitations. The results further indicate that the lower confidence limit of a benchmark response rate of 10% (BMDL(10) ) could be considered a satisfactory POD when analyzing genotoxicity data using the BMD approach. The models described permit the identification of POD values that could be combined with mode of action analysis to determine whether exposure(s) below a particular level constitutes a significant human risk. Subsequent analyses will expand the number of substances and endpoints investigated, and continue to evaluate the utility of quantitative approaches for analysis of genetic toxicity dose-response data. PMID:22987251

Gollapudi, B B; Johnson, G E; Hernandez, L G; Pottenger, L H; Dearfield, K L; Jeffrey, A M; Julien, E; Kim, J H; Lovell, D P; Macgregor, J T; Moore, M M; van Benthem, J; White, P A; Zeiger, E; Thybaud, V

2013-01-01

179

Temple study's pre-clinical data shows Angiocidin effective against leukemia  

Cancer.gov

Angiocidin, a novel tumor-inhibiting protein, has been shown to reduce acute myeloid leukemia (AML) cells in mice by almost two-thirds in pre-clinical experiments. A researcher from Temple University’s School of Medicine who discovered Angiocidin, presented the findings during the American Society of Hematology’s national meeting in Atlanta on Dec. 9. Temple University is home to the Fox Chase Cancer Center.

180

A study on spiral cone beam scanning mode for preclinical micro-CT  

Microsoft Academic Search

In preclinical micro-CT, a circular scanning trajectory is widely used, and the Feldkamp algorithm is usually the standard reconstruction method to recover the images. This imaging mode has the advantages of fast reconstruction speed and good intra-slice resolution for images near the central plane. However, it shows cone-beam artifacts for images at relatively large cone angles. To address this problem,

Junjun Deng; Shikui Yan; Hengyong Yu; Ge Wang; Mu Chen

2009-01-01

181

A QSAR, pharmacokinetic and toxicological study of new artemisinin compounds with anticancer activity.  

PubMed

The Density Functional Theory (DFT) method and the 6-31G** basis set were employed to calculate the molecular properties of artemisinin and 20 derivatives with different degrees of cytotoxicity against the human hepatocellular carcinoma HepG2 line. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were employed to select the most important descriptors related to anticancer activity. The significant molecular descriptors related to the compounds with anticancer activity were the ALOGPS_log, Mor29m, IC5 and GAP energy. The Pearson correlation between activity and most important descriptors were used for the regression partial least squares (PLS) and principal component regression (PCR) models built. The regression PLS and PCR were very close, with variation between PLS and PCR of R2 = ±0.0106, R2ajust = ±0.0125, s = ±0.0234, F(4,11) = ±12.7802, Q2 = ±0.0088, SEV = ±0.0132, PRESS = ±0.4808 and SPRESS = ±0.0057. These models were used to predict the anticancer activity of eight new artemisinin compounds (test set) with unknown activity, and for these new compounds were predicted pharmacokinetic properties: human intestinal absorption (HIA), cellular permeability (PCaCO2), cell permeability Maden Darby Canine Kidney (PMDCK), skin permeability (PSkin), plasma protein binding (PPB) and penetration of the blood-brain barrier (CBrain/Blood), and toxicological: mutagenicity and carcinogenicity. The test set showed for two new artemisinin compounds satisfactory results for anticancer activity and pharmacokinetic and toxicological properties. Consequently, further studies need be done to evaluate the different proposals as well as their actions, toxicity, and potential use for treatment of cancers. PMID:25061720

Vieira, Josinete B; Braga, Francinaldo S; Lobato, Cleison C; Santos, César F; Costa, Josivan S; Bittencourt, José Adolfo H M; Brasil, Davi S B; Silva, Jocivânia O; Hage-Melim, Lorane I S; Macêdo, Williams Jorge C; Carvalho, José Carlos T; Santos, Cleydson Breno R

2014-01-01

182

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

2008-08-01

183

Oral toxicological studies of pueraria flower extract: acute toxicity study in mice and subchronic toxicity study in rats.  

PubMed

Kudzu has been widely used as an herbal medicine in China. The root of the kudzu is also well known as an antipyretic and analgesic in treatment of the common cold, while its flower has been used to treat alcohol intoxication, alcohol abuse, and dysentery. Pueraria flower extract (PFE) is a hot water extract derived from the flower of the kudzu, Pueraria thomsonii Benth. (Fabaceae), oral intake of which exhibits anti-obesity properties in mice and humans. In this study, we conducted acute and subchronic toxicity studies for an evaluation of safety. In the acute study, PFE (5 g/kg body weight) was orally administered to ddY mice. For 14 d after administration, no deaths or abnormal changes were observed in general signs, body weight (BW), or food consumption, and no abnormal findings were observed in the major organs and tissues of either males or females at necropsy. The oral LD50 of PFE was therefore estimated to be higher than 5 g/kg BW. In the subchronic study, PFE was mixed into the diet in place of powdered CRF-1 and administered at concentrations of 0% (control), 0.5%, 1.5%, and 5.0% to male and female Sprague-Dawley rats for 90 d. No mortality or toxicological changes were observed during the experimental period. Blood biochemical, hematological, and urinary parameters revealed no toxicologically significant changes. Furthermore, no anatomical or histopathological changes due to PFE were observed. The no-observed adverse-effect-level of PFE was thus estimated to be 5.0% in the diet (male: 3.0 g/kg BW/d; female: 3.5 g/kg BW/d). PMID:24245900

Takano, Akira; Kamiya, Tomoyasu; Tsubata, Masahito; Ikeguchi, Motoya; Takagaki, Kinya; Kinjo, Junei

2013-11-01

184

Cell-Seeded Tubularized Scaffolds for Reconstruction of Long Urethral Defects: A Preclinical Study  

PubMed Central

Background The treatment options for patients requiring repair of a long segment of the urethra are limited by the availability of autologous tissues. We previously reported that acellular collagen-based tubularized constructs seeded with cells are able to repair small urethral defects in a rabbit model. Objective We explored the feasibility of engineering clinically relevant long urethras for surgical reconstruction in a canine preclinical model. Design, setting, and participants Autologous bladder epithelial and smooth muscle cells from 15 male dogs were grown and seeded onto preconfigured collagen-based tubular matrices (6 cm in length). The perineal urethral segment was removed in 21 male dogs. Urethroplasties were performed with tubularized collagen scaffolds seeded with cells in 15 animals. Tubularized constructs without cells were implanted in six animals. Serial urethrography and three-dimensional computed tomography (CT) scans were performed pre- and postoperatively at 1, 3, 6, and 12 mo. The animals were euthanized at their predetermined time points (three animals at 1 mo, and four at 3, 6, and 12 mo) for analyses. Outcome measurements and statistical analysis Statistical analysis of CT imaging and histology was not needed. Results and limitations CT urethrograms showed wide-caliber urethras without strictures in animals implanted with cell-seeded matrices. The urethral segments replaced with acellular scaffolds collapsed. Gross examination of the urethral implants seeded with cells showed normal-appearing tissue without evidence of fibrosis. Histologically, an epithelial cell layer surrounded by muscle fiber bundles was observed on the cell-seeded constructs, and cellular organization increased over time. The epithelial and smooth muscle phenotypes were confirmed using antibodies to pancytokeratins AE1/AE3 and smooth muscle–specific desmin. Formation of an epithelial cell layer occurred in the unseeded constructs, but few muscle fibers formed. Conclusions Cell-seeded tubularized collagen scaffolds can be used to repair long urethral defects, whereas scaffolds without cells lead to poor tissue development and strictures. This study demonstrates that long tissue-engineered tubularized urethral segments may be used for urethroplasty in patients.

Orabi, Hazem; AbouShwareb, Tamer; Zhang, Yuanyuan; Yoo, James J.; Atala, Anthony

2012-01-01

185

The toxicological response of Brazilian chrysotile asbestos: a multidose subchronic 90-day inhalation toxicology study with 92-day recovery to assess cellular and pathological response.  

PubMed

Inhalation toxicology studies with chrysotile asbestos have in the past been performed at exceedingly high doses without consideration of fiber number or dimensions. As such, the exposures have exceeded lung overload levels, making quantitative assessment of these studies difficult if not impossible. To assess the cellular and pathological response in the rat lung to a well-characterized aerosol of chrysotile asbestos, a 90-day subchronic inhalation toxicology study was performed using a commercial Brazilian chrysotile (CA 300). The protocol was based on that established by the European Commission for the evaluation of synthetic vitreous fibers. The study was also designed to assess the potential for reversibility of any such changes and to permit association of responses with fiber dose in the lung and the influence of fiber length. Wistar male rats were randomly assigned to an air control group and to 2 CA 300 exposure groups at mean fiber aerosol concentrations of 76 fibers L > 20 microm/cm3 (3413 total fibers/cm3; 536 WHO fibers/cm3) or 207 fibers L > 20 microm/cm3 (8941 total fibers/cm3; 1429 WHO fibers/cm3). The animals were exposed using a flow-past, nose-only exposure system for 5 days/wk, 6 h/day, during 13 consecutive weeks (65 exposures), followed by a subsequent nonexposure period lasting for 92 days. Animals were sacrificed after cessation of exposure and after 50 and 92 days of nonexposure recovery. At each sacrifice, subgroups of rats were assessed for the determination of the lung burden; histopathological examination; cell proliferation response; bronchoalveolar lavage with the determination of inflammatory cells; clinical biochemistry; and for analysis by confocal microscopy. Through 90 days of exposure and 92 days of recovery, chrysotile at a mean exposure of 76 fibers L > 20 microm/cm3 (3413 total fibers/cm3) resulted in no fibrosis (Wagner score 1.8 to 2.6) at any time point. The long chrysotile fibers were observed to break apart into small particles and smaller fibers. In vitro modeling has indicated that these particles are essentially amorphous silica. At an exposure concentration of 207 fibers L > 20 microm/cm3 (8941 total fibers/cm3) slight fibrosis was observed. In comparison with other studies, chrysotile produced less inflammatory response than the biosoluble synthetic vitreous fiber CMS. As predicted by the recent biopersistence studies on chrysotile, this study clearly shows that at that at an exposure concentration 5000 times greater than the U.S. threshold limit value of 0.1 f(WHO)/cm3, chrysotile produces no significant pathological response. PMID:16513591

Bernstein, David M; Rogers, Rick; Smith, Paul; Chevalier, Jörg

2006-05-01

186

Threats to Validity in the Design and Conduct of Preclinical Efficacy Studies: A Systematic Review of Guidelines for In Vivo Animal Experiments  

PubMed Central

Background The vast majority of medical interventions introduced into clinical development prove unsafe or ineffective. One prominent explanation for the dismal success rate is flawed preclinical research. We conducted a systematic review of preclinical research guidelines and organized recommendations according to the type of validity threat (internal, construct, or external) or programmatic research activity they primarily address. Methods and Findings We searched MEDLINE, Google Scholar, Google, and the EQUATOR Network website for all preclinical guideline documents published up to April 9, 2013 that addressed the design and conduct of in vivo animal experiments aimed at supporting clinical translation. To be eligible, documents had to provide guidance on the design or execution of preclinical animal experiments and represent the aggregated consensus of four or more investigators. Data from included guidelines were independently extracted by two individuals for discrete recommendations on the design and implementation of preclinical efficacy studies. These recommendations were then organized according to the type of validity threat they addressed. A total of 2,029 citations were identified through our search strategy. From these, we identified 26 guidelines that met our eligibility criteria—most of which were directed at neurological or cerebrovascular drug development. Together, these guidelines offered 55 different recommendations. Some of the most common recommendations included performance of a power calculation to determine sample size, randomized treatment allocation, and characterization of disease phenotype in the animal model prior to experimentation. Conclusions By identifying the most recurrent recommendations among preclinical guidelines, we provide a starting point for developing preclinical guidelines in other disease domains. We also provide a basis for the study and evaluation of preclinical research practice. Please see later in the article for the Editors' Summary

Henderson, Valerie C.; Kimmelman, Jonathan; Fergusson, Dean; Grimshaw, Jeremy M.; Hackam, Dan G.

2013-01-01

187

Nonclinical toxicology studies with zidovudine: acute, subacute, and chronic toxicity in rodents, dogs, and monkeys.  

PubMed

In single dose acute toxicity studies in CD-1 mice and CD rats, the median lethal dose (MLD) for zidovudine (ZDV) was > 750 mg/kg after iv dosing and > 3000 mg/kg after po administration (recommended human dose is 100 mg every 4 hr while awake). Because of the short half-life in rats (0.8 hr), dogs (1.0 hr), and monkeys (0.8 hr), the daily dose of ZDV in most studies was given in two equal portions approximately 6 hr apart. Intravenous administration of ZDV was well tolerated in beagle dogs at dose levels up to 42.5 mg/kg bid for 2 weeks and in CD rats at dose levels up to 75 mg/kg bid for 4 weeks. In a 2-week dose range-finding study in beagle dogs, cytostatic effects were noted at po dose levels of 62.5 to 250 mg/kg bid in certain tissues with rapid cell replication rates. In contrast, in 3- to 12-month oral toxicity studies in CD rats and cynomolgus monkeys, the principal toxicologic finding was reversible macrocytic normochromic anemia which occurred at 225-250 mg/kg bid in rats and 17.5-150 mg/kg bid in monkeys. In the 12-month rat study, RBC was decreased at 25 and 75 mg/kg bid. In the 12-month monkey study WBC was slightly decreased at 150 mg/kg bid. PMID:8921316

Ayers, K M; Tucker, W E; Hajian, G; De Miranda, P

1996-08-01

188

Aerospace Toxicology and Microbiology  

NASA Technical Reports Server (NTRS)

Toxicology dates to the very earliest history of humanity with various poisons and venom being recognized as a method of hunting or waging war with the earliest documentation in the Evers papyrus (circa 1500 BCE). The Greeks identified specific poisons such as hemlock, a method of state execution, and the Greek word toxos (arrow) became the root of our modern science. The first scientific approach to the understanding of poisons and toxicology was the work during the late middle ages of Paracelsus. He formulated what were then revolutionary views that a specific toxic agent or "toxicon" caused specific dose-related effects. His principles have established the basis of modern pharmacology and toxicology. In 1700, Bernardo Ramazzini published the book De Morbis Artificum Diatriba (The Diseases of Workers) describing specific illnesses associated with certain labor, particularly metal workers exposed to mercury, lead, arsenic, and rock dust. Modern toxicology dates from development of the modern industrial chemical processes, the earliest involving an analytical method for arsenic by Marsh in 1836. Industrial organic chemicals were synthesized in the late 1800 s along with anesthetics and disinfectants. In 1908, Hamilton began the long study of occupational toxicology issues, and by WW I the scientific use of toxicants saw Haber creating war gases and defining time-dosage relationships that are used even today.

James, John T.; Parmet, A. J.; Pierson, Duane L.

2007-01-01

189

Toxicologic evaluation of Dichrostachys glomerata extract: Subchronic study in rats and genotoxicity tests.  

PubMed

In western Cameroon, edible fruits and seeds from the plant Dichrostachys glomerata are commonly used as spices. Extract from the fruit pods has been reported as a good natural source of antioxidants and may provide health benefits. The objective of the present study was to investigate potential adverse effects, if any, of D. glomerata fruit pod extract (Dyglomera™) in a subchronic toxicity study and in genotoxicity studies. In the toxicity study, Sprague Dawley rats (20/sex/group) were gavaged with D. glomerata extract at dose levels of 0, 100, 1000 and 2500mg/kg body weight (bw)/day for 90-days. Dyglomera™ administration did not result in mortality or show treatmentrelated changes in clinical signs of toxicity, body weights, body weight gain or feed consumption. Similarly, no toxicologically significant treatment-related changes in hematological, clinical chemistry, urine analysis parameters, and organ weights were noted. Macroscopic and microscopic examinations did not reveal treatment-related abnormalities. Mutagenic and clastogenic potentials as evaluated by Ames assay, in vitro and in vivo chromosomal aberration test and in vivo micronucleus test did not reveal any genotoxicity of the extract. The results of subchronic toxicity study supports the no-observed-adverse-effect level (NOAEL) for D. glomerata extract as 2500mg/kg bw/day, the highest dose tested. PMID:24713264

Kothari, Shil C; Shivarudraiah, Prasad; Venkataramaiah, Suresh Babu; Gavara, Swapna; Arumugam, Shri Natrajan; Soni, Madhu G

2014-07-01

190

Rational design of murine secreted alkaline phosphatase for enhanced performance as a reporter gene in mouse gene therapy preclinical studies.  

PubMed

Many preclinical gene therapy studies use a reporter gene to evaluate vector design and performance in mouse models of human disease. Unfortunately, most commonly used reporter genes are immunogenic in mice, which confounds accurate evaluation of vector function. In previous studies, we showed that the murine secreted alkaline phosphatase (mSEAP) gene functions well as a simple and sensitive reporter gene in mice. In this study, we have used rational design to enhance mSEAP performance. The majority of native mSEAP remains attached to the outer surface of the cell through glycan phosphatidylinositol linkage; removal of the carboxy-terminal tail of mSEAP resulted in a dramatic enhancement of release of the protein into cell culture medium and into mouse plasma in whole animal experiments. We increased the heat stability of mSEAP through mutation of a key residue in the crown domain of the protein (H451E), thus allowing us to reduce endogenous, background AP activity through heat inactivation for enhanced sensitivity. We show that these alterations in mSEAP result in enhanced performance in tissue culture and mouse studies. Taken together, these data illustrate that mSEAP is a sensitive, nonimmunogenic reporter for preclinical mouse studies. PMID:21083426

Christou, Carin; Parks, Robin J

2011-04-01

191

Plant-based medicines for anxiety disorders, part 2: a review of clinical studies with supporting preclinical evidence.  

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. Thus, our aim was to provide a comprehensive narrative review of plant-based medicines that have clinical and/or preclinical evidence of anxiolytic activity. We present the article in two parts. In part one, we reviewed herbal medicines for which only preclinical investigations for anxiolytic activity have been performed. In this current article (part two), we review herbal medicines for which there have been both preclinical and clinical investigations of anxiolytic activity. A search of MEDLINE (PubMed), CINAHL, Scopus and the Cochrane Library databases was conducted (up to 28 October 2012) for English language papers using the search terms 'anxiety' OR 'anxiety disorder' OR 'generalized anxiety disorder' OR 'social phobia' OR 'post-traumatic stress disorder' OR 'panic disorder' OR 'agoraphobia' OR 'obsessive compulsive disorder' in combination with the search terms 'Herb*' OR 'Medicinal Plants' OR 'Botanical Medicine' OR 'Chinese herb*', in addition to individual herbal medicines. This search of the literature revealed 1,525 papers, of which 53 plants were included in the review (having at least one study using the whole plant extract). Of these plants, 21 had human clinical trial evidence (reviewed here in part two), with the other 32 having solely preclinical evidence (reviewed in part one). Support for efficacy was found for chronic use (i.e. greater than one day) of the following herbs in treating a range of anxiety disorders in human clinical trials: Piper methysticum, Matricaria recutita, Ginkgo biloba, Scutellaria lateriflora, Silybum marianum, Passiflora incarnata, Withania somniferum, Galphimia glauca, Centella asiatica, Rhodiola rosea, Echinacea spp., Melissa officinalis and Echium amoenum. For several of the plants studied, conclusions need to be tempered due to methodological issues such as small sample sizes, brief intervention durations and non-replication. Current evidence does not support Hypericum perforatum or Valeriana spp. for any anxiety disorder. Acute anxiolytic activity was found for Centella asiatica, Salvia spp., Melissa officinalis, Passiflora incarnata and Citrus aurantium. Bacopa monnieri has shown anxiolytic effects in people with cognitive decline. The therapeutic application of psychotropic plant-based treatments for anxiety disorders is also discussed, specifically Psychotria viridis and Banisteriopsis caarti (ayahuasca), Psilocybe spp. and cannabidiol-enriched (low tetrahydrocannabinol (?(9)-THC)) Cannabis spp. PMID:23653088

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

2013-04-01

192

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

2013-10-15

193

Preclinical Evaluation of the Immunogenicity and Safety of an Inactivated Enterovirus 71 Candidate Vaccine  

PubMed Central

Human enterovirus 71 (EV71) is a significant cause of morbidity and mortality from Hand, Foot and Mouth Disease (HFMD) and neurological complications, particularly in young children in the Asia-Pacific region. There are no vaccines or antiviral therapies currently available for prevention or treatment of HFMD caused by EV71. Therefore, the development of therapeutic and preventive strategies against HFMD is of growing importance. We report the immunogenic and safety profile of inactivated, purified EV71 preparations formulated with aluminum hydroxide adjuvant in preclinical studies in mice and rabbits. In mice, the candidate vaccine formulations elicited high neutralizing antibody responses. A toxicology study of the vaccine formulations planned for human use performed in rabbits showed no vaccine-related pathological changes and all animals remained healthy. Based on these preclinical studies, Phase 1 clinical testing of the EV71 inactivated vaccine was initiated.

Hwa, Shi-Hsia; Lee, Yock Ann; Brewoo, Joseph N.; Partidos, Charalambos D.; Osorio, Jorge E.; Santangelo, Joseph D.

2013-01-01

194

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

2013-01-01

195

A comparative toxicologic and genotoxic study of the herbicide arsenal, its active ingredient imazapyr, and the surfactant nonylphenol ethoxylate.  

PubMed

The herbicide arsenal 250 NA, its technical-grade active ingredient imazapyr, and the surfactant nonylphenol ethoxylate (NP) were evaluated through genotoxicity and toxicity studies in different organisms. A comparative study of these three compounds was carried out to assess how the addition of surfactant components may pose the highest toxicological risk to pesticide formulations. The results showed that arsenal, imazapyr, and NP did not cause chromosome aberration in Allium cepa nor increase the frequency of micronuclei in mice. However, toxicological evaluations showed that NP was the most toxic compound to mice, A. cepa, Drosophila melanogaster, and Biomphalaria tenagophila. In this evaluation, it was observed that the adverse effects were produced by the surfactant additive of the pesticide formulation. PMID:15261733

Grisolia, Cesar Koppe; Bilich, Marina Rolim; Formigli, Lia Menezes

2004-09-01

196

Dicycloplatin, a novel platinum analog in chemotherapy: synthesis of chinese pre-clinical and clinical profile and emerging mechanistic studies.  

PubMed

Dicycloplatin (DCP) has better solubility and stability than both cisplatin and carboplatin. Pre-clinical and phase I studies demonstrated significant antitumor activity and fewer adverse events than carboplatin. Phase II clinical trials in advanced non-small cell lung cancer found efficacy and safety of DCP-plus-paclitaxel comparable to carboplatin-plus-paclitaxel but better tolerability. This article summarizes and reviews pre-clinical and clinical data for dicycloplatin from the Chinese medical literature. We also report on new mechanistic findings in our laboratory in West Virginia, USA. Patient blood samples were collected for DCP-prototype determination by liquid chromatography mass spectrometry (LC-MS/MS). Molecular studies of ovarian cancer cells treated with DCP or cisplatin were carried out for gene-signature profiling using immunoblotting. Pharmacokinetic mass-spectrometry showed different spectrum profiles of DCP and carboplatin in plasma. Plasma concentration of DCP prototype was 17.1 ?g/ml 2h after administration, with a peak concentration of 26.9 ?g/ml at 0.5 h. Immunoblotting showed DCP-induced activation of DNA damage pathways, including double-phosphorylated checkpoint kinase 2 (CHK2) and breast cancer 1 (BRCA1) and triple-phosphorylated p53, compared to controls. Cisplatin produced a similar profile, with increased p53 protein. DCP and cisplatin activate DNA-damage response through similar pathways. DCP may be more soluble and stable, and better-tolerated. PMID:24403501

Yu, Jing Jie; Yang, Xuqing; Song, Qinhua; Mueller, Michael D; Remick, Scot C

2014-01-01

197

Focused Ultrasound-Induced Blood-Brain Barrier Opening to Enhance Temozolomide Delivery for Glioblastoma Treatment: A Preclinical Study  

PubMed Central

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.

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

2013-01-01

198

Incorporation of a micronucleus study into a developmental toxicology and pharmacokinetic study of L-selenomethionine in nonhuman primates  

SciTech Connect

Concomitant to a developmental toxicology study of selenium in long-tailed macaques (Macaca fascicularis), a transplacental bone marrow micronucleus assay was conducted in the fetuses of treated animals. Selenium was administered as L-selenomethionine by nasogastric intubation at 0, 150 or 300 [mu]g/kg-day to pregnant macaques daily throughout organogenesis (gestation days 20-50). Pregnancy was terminated on gestation day 100 [+-] 2 and fetuses were obtained by hysterotomy. Selenium concentrations in maternal blood were monitored throughout pregnancy and selenium concentrations in fetal blood were measured at hysterotomy. Maternal circulating selenium did not exceed 4 ppm in plasma or 3.7 ppm in erthrocytes. Selenium in cord blood was [<=] 0.1 ppm in plasma and [<=] 1.1 ppm in erthrocytes at 300 [mu]g/kg-day. Fetal bone marrow smears were prepared from the humerus and micronucleated polychromatic erythrocytes were scored. No increase of micronucleus frequency was detected in any dose group, although signs of maternal selenosis were obvious. This finding is compared to the previous observation that micronuclei were induced in the bone marrow of adult nonpregnant macaques treated at 600 [mu]g/kg-day, a lethal dose yielding blood selenium levels to 7.3 ppm in plasma and 5.7 ppm in erthyrocytes after 15 days of daily treatment, when death occurred. These data demonstrate that measurement of circulating xenobiotics can be useful for the interpretation of genetic toxicology results. 32 refs., 4 figs., 4 tabs.

Choy, Wai Nang; Henika, P.R.; Willhite, C.C.; Tarantal, A.F. (Univ. of California, Davis, CA (United States))

1993-01-01

199

Alternatives in pharmaceutical toxicology: global and focussed approaches--two case studies.  

PubMed

Safety testing of potential drugs has been and will continue to be a challenging task for the toxicologist in the pharmaceutical industry. We present two examples for the use of target-specific cell models to detect and assess species-specific toxicity. In the first example, adrenal models based on primary cells as well as a permanent human adrenal cell line were used. Both cell systems enabled a good prediction of adrenal effects in rodents, non-rodents and humans. The second example made use of primary hepatocytes. In this project, a potential drug candidate showed unexpected toxicity in vitro as well as species-specific cytochrome P450 (CYP) induction in vivo. We therefore analysed CYP induction and gene expression signatures in rat and human hepatocytes as well as in samples from in vivo animal toxicity studies. By this approach, the rat hepatocyte model correctly predicted the effects observed in rats and the in vitro/in vivo comparison enabled a solid extrapolation of consequences in humans. These examples demonstrate that an intelligent testing strategy, using alternative methods, can enable a meaningful safety assessment for humans by adding a ''tailor-made'' range of technologies to ''classic'' toxicological methods. PMID:17728977

Mueller, Stefan O; Tuschl, Gregor; Kling, Margret

2007-01-01

200

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

201

Toxicology: Statistical perspectives  

Microsoft Academic Search

Toxicity abounds in nature, environment, and in our modern life-style. Toxicology relates to the study of the intake process of such toxins by human being, their mode of propagation, biological reactions, molecular level of penetration, genotoxicity and afte rmaths. Because of the latent nature of a large class of toxic substances, the extreme variability of human metabo- lism as well

Pranab Kumar Sen

2001-01-01

202

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

203

Reducing attrition in drug development: smart loading preclinical safety assessment.  

PubMed

Entry into the crucial preclinical good laboratory practice (GLP) stage of toxicology testing triggers significant R&D investment yet >20% of AstraZeneca's potential new medicines have been stopped for safety reasons in this GLP phase alone. How could we avoid at least some of these costly failures? An analysis of historical toxicities that caused stopping ('stopping toxicities') showed that >50% were attributable to target organ toxicities emerging within 2 weeks of repeat dosing or to acute cardiovascular risks. By frontloading 2-week repeat-dose toxicity studies and a comprehensive assessment of cardiovascular safety, we anticipate a potential 50% reduction in attrition in the GLP phase. This will reduce animal use overall, save significant R&D costs and improve drug pipeline quality. PMID:24269835

Roberts, Ruth A; Kavanagh, Stefan L; Mellor, Howard R; Pollard, Christopher E; Robinson, Sally; Platz, Stefan J

2014-03-01

204

Contraceptive evaluation and toxicological study of aqueous extract of the seeds of Carica papaya in male rabbits.  

PubMed

The contraceptive evaluation and toxicological effects of the aqueous extract of the seeds of Carica papaya in adult male rabbits have been reported. Thirty adult male rabbits were divided into five groups of six animals each; Group I, control; Groups II-V were administered orally with aqueous extract of the seeds of C. papaya at doses of 20, 50, 75 and 100 mg/kg per day for 150 days, respectively. The body weight, reproductive organs weight, semen analysis, semen biochemistry, toxicological profiles and the fertility status have been recorded. The aqueous extract failed to exhibit contraceptive effects at any of the dose regimens tested, contrary to the observations made in the previous studies. Unaltered toxicological profiles indicated that the drug was free of side effects. The results suggest that the failure of contraceptive effects may be due to species specificity, relative resistance of the animals to the drug or lack of potency of the extract due to factors generally affect biological activity of the plant preparations. PMID:10720785

Lohiya, N K; Pathak, N; Mishra, P K; Manivannan, B

2000-04-01

205

Studies on the metabolism and toxicological detection of the new designer drug N-benzylpiperazine in urine using gas chromatography–mass spectrometry  

Microsoft Academic Search

Studies are described on the metabolism and on the toxicological analysis of the piperazine-like designer drug N-benzylpiperazine (BZP, scene name “A2”) in rat and human urine using gas chromatography–mass spectrometry (GC–MS). The identified metabolites indicated that BZP was hydroxylated at the aromatic ring and that the piperazine moiety is metabolically degraded. Our systematic toxicological analysis (STA) procedure using full-scan GC–MS

Roland F. Staack; Giselher Fritschi; Hans H. Maurer

2002-01-01

206

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

207

[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

1998-01-01

208

Feasibility study of an online toxicological sensor based on the optical waveguide technique.  

PubMed

Morphological properties of the cells often change as an early response to the presence of a pharmacologically acting toxic substance [Etcheverry, S.B., Crans, D.C., Keramidas, A.D., Cortizo, A.M., Arch. Biochem. Biophys. 338 (1997) 7-14]. Recently it has been shown that living animal cell adhesion and spreading can be monitored online and quantitatively via the interaction of the cells with the evanescent electromagnetic field present at the surface of an optical waveguide [Ramsden, J.J., Li, S.Y., Heinzle, E., Prinosil, J.E. Cytometry 19 (1995) 97-102]. In the present study, optical waveguide lightmode spectroscopy (OWLS) and confocal laser scanning microscopy (CLSM), which provides information about the shape of the cells at the surface, were compared under identical experimental conditions. This allowed for the correlation between the cell-shape information from CLSM and the cell-surface interaction measurements from OWLS. The proposed design of the microsystem sensor involves the establishment of a cell layer on the surface of the waveguide and the subsequent online measurement of the morphological response of the cells to various toxic substances. In the present study, the setup was evaluated using cells from an osteoblastic MC 3T3-E1 cell line, and sodium hypochlorite was used as model toxic substance. Comparing the OWLS signal to the morphological response measured by CLSM reveals that OWLS is effective in monitoring not only cell attachment and spreading but also the cellular response to toxic compounds (i.e. by means of change in cell morphology). For the model toxin, the OWLS measurements indicate that, at concentrations above 0.01%, the cells exhibit a clearly discernable morphological effect (i.e. a decrease in average cell contact area). Thus, the potential of an on-line sensor based on OWLS to applications in toxicology, pharmacy and biocompatibility was demonstrated. PMID:11419636

Vörös, J; Graf, R; Kenausis, G L; Bruinink, A; Mayer, J; Textor, M; Wintermantel, E; Spencer, N D

2000-01-01

209

Activity of PXD101, a histone deacetylase inhibitor, in preclinical ovarian cancer studies.  

PubMed

Histone deacetylase inhibitors represent a promising new class of anticancer agents. In the current investigation, we examined the activity of PXD101, a potent histone deacetylase inhibitor, used alone or in combination with clinically relevant chemotherapeutics (docetaxel, paclitaxel, and carboplatin), in preclinical in vitro and in vivo models of ovarian cancer. In vitro activity was examined in ovarian cancer and multidrug-resistant cell lines grown in monolayer culture, and in primary clinical ovarian cancer specimens grown in three-dimensional organoid culture. PXD101 was found to inhibit in vitro cancer cell growth at sub- to low micromolar IC(50) potency, exhibited synergistic activity when used in combination with relevant chemotherapeutics, and effectively inhibited the growth of multidrug-resistant cells. In vivo, PXD101 displayed single-agent antitumor activity on human A2780 ovarian cancer s.c. xenografts which was enhanced via combination therapy with carboplatin. In support of these findings, PXD101 was shown to increase the acetylation of alpha-tubulin induced by docetaxel and the phosphorylation of H2AX induced by carboplatin. Taken together, these results support the clinical evaluation of PXD101 used alone or in combination therapy for the treatment of ovarian cancer. PMID:16928830

Qian, Xiaozhong; LaRochelle, William J; Ara, Gulshan; Wu, Frank; Petersen, Kamille Dumong; Thougaard, Annemette; Sehested, Maxwell; Lichenstein, Henri S; Jeffers, Michael

2006-08-01

210

A toxicological study of HangAmDan-B in mice.  

PubMed

The aim of the study was to define the toxicity of HangAmDan-B (HAD-B) in mice over the short and long term. HAD-B was studied in 1-week single and 5-week repeated oral dose toxicity tests on male Imprinting Control Region mice. Doses used in 1 week single oral dose toxicity tests were 0, 0.2, 1, 5, and 25 g/kg/day and those of repeated toxicity test were 0, 0.04, 0.2, 1, and 2 g/kg/day. Blood and urine samples were assayed and their morphology observed. Numerical data were compared using Mann-Whitney U test and analysis of variance. Significantly decreased red blood cell levels in mice from S2-HAD-B, S3-HAD-B, S4-HAD-B, and S5-HAD-B groups were observed in single oral dose toxicity tests. Hemoglobin, hematocrit, and mean cell hemoglobin values in mice from the S4-HAD-B and S5-HAD-B groups were also significantly decreased. No mortalities or significant differences in all factors were observed during the dosing period of the repeated dose toxicity test. Administering 2 g/kg/day of HAD-B in mice over a 5-week period showed no significant hematological changes. However, risk of anemia with more than 5 g/kg/ day administration of HAD-B was found. In general, HAD-B appears to be safe and nontoxic, and a no observed adverse effect level in mice was established at 2 g/kg/ day. This data serves as satisfactory preclinical evidence for the safety of HAD-B should a future clinical trial for HAD-B be launched. Further studies are required to confirm these safety results and to carry out a safety trial in humans. PMID:21440880

Yoo, Hwa-Seung; Lee, Hyo-Jae; Kim, Jung-Sun; Yoon, Jeungwon; Lee, Grace H; Lee, Yeon-Weol; Cho, Chong-Kwan

2011-03-01

211

Analysis of machine perfusion benefits in kidney grafts: a preclinical study  

PubMed Central

Background Machine perfusion (MP) has potential benefits for marginal organs such as from deceased from cardiac death donors (DCD). However, there is still no consensus on MP benefits. We aimed to determine machine perfusion benefits on kidney grafts. Methods We evaluated kidney grafts preserved in ViaspanUW or KPS solutions either by CS or MP, in a DCD pig model (60 min warm ischemia + 24 h hypothermic preservation). Endpoints were: function recovery, quality of function during follow up (3 month), inflammation, fibrosis, animal survival. Results ViaspanUW-CS animals did not recover function, while in other groups early follow up showed similar values for kidney function. Alanine peptidase and ?-NAG activities in the urine were higher in CS than in MP groups. Oxydative stress was lower in KPS-MP animals. Histology was improved by MP over CS. Survival was 0% in ViaspanUW-CS and 60% in other groups. Chronic inflammation, epithelial-to-mesenchymal transition and fibrosis were lowest in KPS-MP, followed by KPS-CS and ViaspanUW-MP. Conclusions With ViaspanUW, effects of MP are obvious as only MP kidney recovered function and allowed survival. With KPS, the benefits of MP over CS are not directly obvious in the early follow up period and only histological analysis, urinary tubular enzymes and red/ox status was discriminating. Chronic follow-up was more conclusive, with a clear superiority of MP over CS, independently of the solution used. KPS was proven superior to ViaspanUW in each preservation method in terms of function and outcome. In our pre-clinical animal model of DCD transplantation, MP offers critical benefits.

2011-01-01

212

Toxicology and Carcinogenesis Studies of Monochloroacetic Acid (CAS No. 79-11-8) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies of monochloroacetic acid were conducted by administering the chemical at doses of 0, 15, or 30 mg/kg by gavage in deionized water to groups of 70 rats of each sex and at doses of 0, 50, or 100 mg/kg to groups of 60 mi...

1992-01-01

213

Toxicology and Carcinogenesis Studies of Two Pentachlorophenol Technical-Grade Mixtures (Cas No. 87-86-5) in B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenicity studies were conducted by administering diets containing 100 or 200 ppm technical-grade pentachlorophenol or 100, 200 or 600 ppm Dowicide EC-7 to groups of 50 male and 50 female mice. Two groups of 35 male and 35 fe...

E. E. McConnell

1989-01-01

214

Toxicology and Carcinogenesis Studies of Tetranitromethane (CAS NO. 509-14-8) in F344/N Rats and B6C3F1 Mice (Inhalation Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies of tetranitromethane were conducted by exposing groups of 50 rats of each sex to air containing tetranitromethane at target concentrations of 0 (chamber controls), 2, or 3 ppm, 6 hours per day, 5 days per week for 103...

J. Bucher

1990-01-01

215

Toxicology and Carcinogenesis Studies of C.I. Acid Red 114 (CAS No. 6459-94-5) in F344/N Rats (Drinking Water Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies were conducted by administering desalted, industrial grade C. I. Acid Red 114 in drinking water to groups of F344/N rats of each sex for 104 weeks. Male rats received 0, 70, 150, or 300 ppm C. I. Acid Red 114, female ...

1991-01-01

216

Toxicology and Carcinogenesis Studies of 3,3'-Dimethoxybenzidine Dihydrochloride (CAS No. 20325-40-0) in F344/N Rats (Drinking Water Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies were conducted by administering doses of 0, 80, 170 or 330 ppm 3,3'-dimethoxybenzidine dihydrochloride in drinking water to groups of F344/N rats of each sex for a period of 21 months. Under the conditions of these 21...

D. Morgan

1990-01-01

217

Toxicology and Carcinogenesis Studies of C.I. Direct Blue 15 (Cas No. 2429-74-5) in F344/N Rats (Drinking Water Studies).  

National Technical Information Service (NTIS)

Twenty-two month toxicology and carcinogenesis studies were conducted by administering to male and female rats doses of 0, 630, 1250, or 2500 ppm C. I. Direct Blue 15 in distilled drinking water for 96 weeks. There were 70 rats per control group, 45 rats ...

1992-01-01

218

Toxicology and Carcinogenesis Studies of Benzaldehyde (Cas No. 100-52-7) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies were conducted by administering 0, 200, or 400 mg/kg benzaldehyde in corn oil by gavage, 5 days per week for 103 weeks to groups of 50 male and 50 female rats and for 104 weeks to groups of 50 male mice. Grou...

J. Bishop

1990-01-01

219

Toxicology and Carcinogenesis Studies of Bromodichloromethane (CAS No. 75-27-4) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies of bromodichloromethane were conducted by administering the chemical in corn oil, by gavage, 5 days per week of 102 weeks, to groups of 50 male and 50 female rats at doses of 0, 50, or 100 mg/kg per day; to g...

1987-01-01

220

Toxicology and Carcinogenesis Studies of Pentachloroanisole (Cas No. 1825-21-4) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies were conducted by administering pentachloroanisole in corn oil by gavage 5 days per week for up to 2 years to groups of 70 rats and 70 mice of each sex. Male rats received doses of 0, 10, 20, and 40 mg/kg pentachloroa...

1993-01-01

221

Toxicology and Carcinogenesis Studies of p-Nitroaniline (Cas No. 100-01-6) in B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies were conducted in groups of 70 male and 70 female B6C3F1 mice receiving p-nitroaniline in corn oil by gavage at doses of 0, 3, 30, or 100 mg/kg body weight for 5 days per week for up to 103 weeks. Under the c...

1993-01-01

222

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

223

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

224

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

225

Toxicology and Carcinogenesis Studies of Phenylephrine Hydrochloride (CAS No. 61-76-7) in F344/N Rats and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies of USP-grade phenylephrine hydrochloride were conducted by administering diets containing the chemical to F344/N rats and B6C3F1 mice of each sex at doses of 0, 620, and 1,250 ppm for rats and 0, 1,250, and 2...

1987-01-01

226

Toxicology and Carcinogenesis Studies of Furosemide (Cas No. 54-31-9) in F344/N Rats and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Furosemide is a diuretic used in human and veterinary medicine. Toxicology and carcinogenesis studies were conducted by feeding diets containing furosemide (99% pure, USP grade) to groups of F344/N rats and B6C3F1 mice of each sex for 14 days, 13 weeks, o...

1989-01-01

227

Toxicology and Carcinogenesis Studies of Phenylbutazone (Cas No. 50-33-9) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies were conducted by administering 0, 50, or 100 mg/kg phenylbutazone in corn oil by gavage to groups of 50 rats of each sex, 5 days per week for 103 weeks. The doses administered to groups of 50 mice of each se...

F. W. Kari

1990-01-01

228

Toxicology and Carcinogenesis Studies of 4-Hexylresorcinol (CAS NO. 136-77-6) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies were conducted by administering 4-hexylresorcinol at dose levels of 0, 62.5 or 125 mg/kg in corn oil by gavage to groups of 50 F344/N rats and 50 B6C3F1 mice of each sex 5 days per week for 104 weeks. Under t...

1988-01-01

229

Toxicology and Carcinogenesis Studies of 2-Mercaptobenzothiazole in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies of technical grade 2-mercaptobenzothiazole were conducted by administering the chemical in corn oil by gavage to 50 animals of each species and sex 5 days per week for 103 weeks. Under the conditions of these...

M. P. Dieter

1988-01-01

230

Toxicology and Carcinogenesis Studies of Nickel Subsulfide (CAS No. 12035-72-2) in F344/N Rats and B6C3F1 Mice (Inhalation Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenicity studies were conducted by inhalation administration of nickel subsulfide to a core group of 63 F344/N rats of each sex at 0, 0.15 or 1 mg (equivalent to 0, 0.11 or 0.73 nickel mg/m3) for 6 hours per day, 5 days per week, for...

1996-01-01

231

Toxicology and Carcinogenesis Studies of Nickel Oxide (CAS No. 1313-99-1) in F344/N Rats and B6C3F1 Mice (Inhalation Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenicity studies were conducted by inhalation administration of nickel oxide (high temperature nickel oxide) to groups of 65 F344/N rats at exposures of 0, 0.62, 1.25, or 2.5 mg (equivalent to 0, 0.5, 1.0 or 2.0 mg) and to groups of ...

1996-01-01

232

Toxicology and Carcinogenesis Studies of Rotenone (CAS No. 83-79-4) in F344/N Rats and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies were conducted by administering diets containing 0, 38, or 75 ppm rotenone to groups of 50 F344/N rats of each sex for 103 weeks. Groups of 50 B6C3F(sub 1) mice of each sex were administered diets containing ...

K. M. Abdo

1988-01-01

233

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

234

Efficacy of screens in removing long fibers from an aerosol stream--sample preparation technique for toxicology studies.  

PubMed

Fiber dimension (especially length) and biopersistence are thought to be important variables in determining the pathogenicity of asbestos and other elongate mineral particles. In order to prepare samples of fibers for toxicology studies, it is necessary to develop and evaluate methods for separating fibers by length in the micrometer size range. In this study, we have filtered an aerosol of fibers through nylon screens to investigate whether such screens can efficiently remove the long fibers (L >20 µm, a typical macrophage size) from the aerosol stream. Such a sample, deficient in long fibers, could then be used as the control in a toxicology study to investigate the role of length. A well-dispersed aerosol of glass fibers (a surrogate for asbestos) was generated by vortex shaking a Japan Fibrous Material Research Association (JFMRA) glass fiber powder. Fibers were collected on a mixed cellulose ester (MCE) filter, imaged with phase contrast microscopy (PCM) and lengths were measured. Length distributions of the fibers that penetrated through various screens (10, 20 and 60?µm mesh sizes) were analyzed; additional study was made of fibers that penetrated through double screen and centrally blocked screen configurations. Single screens were not particularly efficient in removing the long fibers; however, the alternative configurations, especially the centrally blocked screen configuration, yielded samples substantially free of the long fibers. PMID:24417374

Ku, Bon Ki; Deye, Gregory J; Turkevich, Leonid A

2014-02-01

235

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

236

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

237

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

238

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

239

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

240

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

241

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

242

Preclinical studies of N3-O-toluyl-fluorouracil-loaded lipid-based nanosuspensions in H22-bearing mice  

PubMed Central

Purpose N3-O-toluyl-fluorouracil (TFU) is a potential antitumor prodrug of 5-fluorouracil (5-FU), but its poor solubility has limited its use in clinic. This study aimed to improve the bioavailability of TFU by preparing TFU-loaded lipid-based nanosuspensions (TFU-LNS) and perform a preclinical evaluation. Methods TFU-LNS were prepared through high-pressure homogenization and were lyophilized afterwards. For in vitro test, the physicochemical properties and cytotoxicity against HegG2 cells were conducted. For in vivo evaluation, the pharmacokinetics, tissue distribution, and antitumor efficacy were investigated in H22-bearing Kunming mice. Results TFU showed different degradability in four media; in particular, nearly all of it converted to an equimolar amount of 5-FU in blank plasma of Wistar rats. The lyophilized TFU-LNS had a mean particle size of 180.03±3.11 nm and zeta potential of ?8.02±1.43 mV and showed no discernible changes after storage at 4°C for 3 months. In the in vivo antitumor study, the antitumor efficacy of TFU-LNS was consistent with that of 5-FU injection. Furthermore, TFU-LNS released a lower concentration of 5-FU in heart and kidney throughout the tissue distribution studies. Conclusion TFU-LNS exhibited convincing antitumor activity and easy scale-up opportunity, which suggests that TFU-LNS might be a promising drug delivery system for cancer therapy.

Zhang, Juan; Li, Min; Liu, Zhihong; Wang, Lili; Liu, Yongjun; Zhang, Na

2014-01-01

243

Pre-clinical toxicokinetics and safety study of M2ES, a PEGylated recombinant human endostatin, in rhesus monkeys.  

PubMed

PEGylated recombinant human endostatin (M2ES) exhibited prolonged serum half-life and enhanced antitumor activity when compared with endostatin. A non-clinical study was performed to evaluate the toxicokinetics and safety of M2ES in rhesus monkeys. After intravenous (IV) infusions of M2ES at a dose level of 3, 10, and 30mg/kg in rhesus monkeys, the concentration-time curves of M2ES were best fitted to a non-compartment model, and area under the curve (AUC) was positively correlated with the dosage. M2ES had a tendency to accumulate in vivo following successive IV infusions. Serum anti-M2ES IgG antibodies were generated quickly during IV administration, and the antibody level in serum did not significantly decrease after four-week recovery period. Animals administered IV infusions twice weekly (M2ES at 10 or 30mg/kg body weight per day) for 3months developed mild or moderate vacuolation of proximal tubule epithelial cell in proximal convoluted tubule of kidney, but this adverse-effect was reversible. In summary, M2ES was well tolerated and did not cause any serious toxicity. These pre-clinical safety data contribute to the initiation of the ongoing clinical study. PMID:24878240

Guo, Lifang; Geng, Xingchao; Chen, Yang; Qi, Feifei; Liu, Li; Miao, Yufa; Lin, Zhi; Yu, Min; Li, Zuogang; Fu, Yan; Li, Bo; Luo, Yongzhang

2014-08-01

244

Preclinical PK and PD studies on 2'-O-methyl-phosphorothioate RNA antisense oligonucleotides in the mdx mouse model.  

PubMed

Antisense oligonucleotides (AONs) are being developed as RNA therapeutic molecules for Duchenne muscular dystrophy. For oligonucleotides with the 2'-O-methyl-phosphorothioate (2OMePS) RNA chemistry, proof of concept has been obtained in patient-specific muscle cell cultures, the mouse and dog disease models, and recently by local administration in Duchenne patients. To further explore the pharmacokinetic (PK)/pharmacodynamic (PD) properties of this chemical class of oligonucleotides, we performed a series of preclinical studies in mice. The results demonstrate that the levels of oligonucleotides in dystrophin-deficient muscle fibers are much higher than in healthy fibers, leading to higher exon-skipping levels. Oligonucleotide levels and half-life differed for specific muscle groups, with heart muscle showing the lowest levels but longest half-life (approximately 46 days). Intravenous (i.v.), subcutaneous (s.c.), and intraperitoneal (i.p.) delivery methods were directly compared. For each method, exon-skipping and novel dystrophin expression were observed in all muscles, including arrector pili smooth muscle in skin biopsies. After i.v. administration, the oligonucleotide peak levels in plasma, liver, and kidney were higher than after s.c. or i.p. injections. However, as the bioavailability was similar, and the levels of oligonucleotide, exon-skipping, and dystrophin steadily accumulated overtime after s.c. administration, we selected this patient-convenient delivery method for future clinical study protocols. PMID:20407428

Heemskerk, Hans; de Winter, Christa; van Kuik, Petra; Heuvelmans, Niki; Sabatelli, Patrizia; Rimessi, Paola; Braghetta, Paola; van Ommen, Gert-Jan B; de Kimpe, Sjef; Ferlini, Alessandra; Aartsma-Rus, Annemieke; van Deutekom, Judith C T

2010-06-01

245

Preclinical PK and PD Studies on 2?-O-Methyl-phosphorothioate RNA Antisense Oligonucleotides in the mdx Mouse Model  

PubMed Central

Antisense oligonucleotides (AONs) are being developed as RNA therapeutic molecules for Duchenne muscular dystrophy. For oligonucleotides with the 2?-O-methyl-phosphorothioate (2OMePS) RNA chemistry, proof of concept has been obtained in patient-specific muscle cell cultures, the mouse and dog disease models, and recently by local administration in Duchenne patients. To further explore the pharmacokinetic (PK)/pharmacodynamic (PD) properties of this chemical class of oligonucleotides, we performed a series of preclinical studies in mice. The results demonstrate that the levels of oligonucleotides in dystrophin-deficient muscle fibers are much higher than in healthy fibers, leading to higher exon-skipping levels. Oligonucleotide levels and half-life differed for specific muscle groups, with heart muscle showing the lowest levels but longest half-life (~46 days). Intravenous (i.v.), subcutaneous (s.c.), and intraperitoneal (i.p.) delivery methods were directly compared. For each method, exon-skipping and novel dystrophin expression were observed in all muscles, including arrector pili smooth muscle in skin biopsies. After i.v. administration, the oligonucleotide peak levels in plasma, liver, and kidney were higher than after s.c. or i.p. injections. However, as the bioavailability was similar, and the levels of oligonucleotide, exon-skipping, and dystrophin steadily accumulated overtime after s.c. administration, we selected this patient-convenient delivery method for future clinical study protocols.

Heemskerk, Hans; de Winter, Christa; van Kuik, Petra; Heuvelmans, Niki; Sabatelli, Patrizia; Rimessi, Paola; Braghetta, Paola; van Ommen, Gert-Jan B; de Kimpe, Sjef; Ferlini, Alessandra; Aartsma-Rus, Annemieke; van Deutekom, Judith CT

2010-01-01

246

Common handling procedures conducted in preclinical safety studies result in minimal hepatic gene expression changes in sprague-dawley rats.  

PubMed

Gene expression profiling is a tool to gain mechanistic understanding of adverse effects in response to compound exposure. However, little is known about how the common handling procedures of experimental animals during a preclinical study alter baseline gene expression. We report gene expression changes in the livers of female Sprague-Dawley rats following common handling procedures. Baseline gene expression changes identified in this study provide insight on how these changes may affect interpretation of gene expression profiles following compound exposure. Rats were divided into three groups. One group was not subjected to handling procedures and served as controls for both handled groups. Animals in the other two groups were weighed, subjected to restraint in Broome restrainers, and administered water via oral gavage daily for 1 or 4 days with tail vein blood collections at 1, 2, 4, and 8 hours postdose on days 1 and 4. Significantly altered genes were identified in livers of animals following 1 or 4 days of handling when compared to the unhandled animals. Gene changes in animals handled for 4 days were similar to those handled for 1 day, suggesting a lack of habituation. The altered genes were primarily immune function related genes. These findings, along with a correlating increase in corticosterone levels suggest that common handling procedures may cause a minor immune system perturbance. PMID:24551150

He, Yudong D; Karbowski, Christine M; Werner, Jon; Everds, Nancy; Di Palma, Chris; Chen, Yuan; Higgins-Garn, Marnie; Tran, Sandra; Afshari, Cynthia A; Hamadeh, Hisham K

2014-01-01

247

Dillenia species: A review of the traditional uses, active constituents and pharmacological properties from pre-clinical studies.  

PubMed

Abstract Context: Dillenia (Dilleniaceae) is a genus of about 100 species of flowering plants in tropical and subtropical trees of Southern Asia, Australasia, and the Indian Ocean Islands. Until now, only eight Dillenia species have been reported to be used traditionally in different countries for various medical purposes. Out of eight species, D. pentagyna (Roxb), D. indica (Linn.) and D. suffruticosa (Griffith Ex. Hook. F. & Thomsom Martelli) have been reported to be used to treat cancerous growth. Objective: The present review explored and provided information on the therapeutic potential of Dillenia species. Methods: Comprehensive and relevant literature on the therapeutic potential of Dillenia species was gathered through electronic databases including Google Scholar, Scopus, PubMed, and books, without limiting the dates of publication. Results and conclusion: The review demonstrated that only a few Dillenia species have been proven scientifically for their therapeutic potential in pre-clinical studies, including D. pentagyna, D. indica, D. papuana (Martelli), D. meliosmifolia (Hook. F. Ex. Thomsom) and D. suffruticosa (Griffith Ex Hook. F. & Thomson). A few species of Dillenia have undergone isolation and characterization of compounds with lupeol and betulinic acids having tremendous pharmacological potential. Dillenia species warrant further studies on their therapeutic potential, which may eventually lead to the development of new drug candidates for treatment of various diseases. PMID:24766363

Saiful Yazan, Latifah; Armania, Nurdin

2014-07-01

248

Investigation of the robustness of two models for assessing synergy in pre-clinical drug combination studies.  

PubMed

Pre-clinical studies may be used to screen for synergistic combinations of drugs. The types of in vitro assays used for this purpose will depend upon the disease area of interest. In oncology, one frequently used study measures cell line viability: cells placed into wells on a plate are treated with doses of two compounds, and cell viability is assessed from an optical density measurement corrected for blank well values. These measurements are often transformed and analysed as cell survival relative to untreated wells. The monotherapies are assumed to follow the Hill equation with lower and upper asymptotes at 0 and 1, respectively. Additionally, a common variance about the dose-response curve may be assumed. In this paper, we consider two models for incorporating synergy parameters. We investigate the effect of different models of biological variation on the assessment of synergy from both of these models. We show that estimates of the synergy parameters appear to be robust, even when estimates of the other model parameters are biased. Using untransformed measurements provides better coverage of the 95% confidence intervals for the synergy parameters than using transformed measurements, and the requirement to fit the upper asymptote does not cause difficulties. Assuming homoscedastic variances appears to be robust. The added complexity of determining and fitting an appropriate heteroscedastic model does not seem to be justified. PMID:23907796

Whitehead, Anne; Su, Ting-Li; Thygesen, Helene; Sperrin, Matthew; Harbron, Chris

2013-01-01

249

Curcumin nanoformulations: a review of pharmaceutical properties and preclinical studies and clinical data related to cancer treatment.  

PubMed

Curcumin, a natural yellow phenolic compound, is present in many kinds of herbs, particularly in Curcuma longa Linn. (turmeric). It is a natural antioxidant and has shown many pharmacological activities such as anti-inflammatory, anti-microbial, anti-cancer, and anti-Alzheimer in both preclinical and clinical studies. Moreover, curcumin has hepatoprotective, nephroprotective, cardioprotective, neuroprotective, hypoglycemic, antirheumatic, and antidiabetic activities and it also suppresses thrombosis and protects against myocardial infarction. Particularly, curcumin has demonstrated efficacy as an anticancer agent, but a limiting factor is its extremely low aqueous solubility which hampers its use as therapeutic agent. Therefore, many technologies have been developed and applied to overcome this limitation. In this review, we summarize the recent works on the design and development of nano-sized delivery systems for curcumin, including liposomes, polymeric nanoparticles and micelles, conjugates, peptide carriers, cyclodextrins, solid dispersions, lipid nanoparticles and emulsions. Efficacy studies of curcumin nanoformulations using cancer cell lines and in vivo models as well as up-to-date human clinical trials are also discussed. PMID:24439402

Naksuriya, Ornchuma; Okonogi, Siriporn; Schiffelers, Raymond M; Hennink, Wim E

2014-03-01

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

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

252

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

253

Further evaluation of the incorporation of an immunotoxicological functional assay for assessing humoral immunity for hazard identification purposes in rats in a standard toxicology study  

Microsoft Academic Search

A previous study (Ladics et al., 1995) conducted in our laboratory using the known immunosuppressant agent, cyclophosphamide, indicated that a functional assay for assessment of humoral immunity may be conducted in rats in a standard toxicology study. The objective of this study was to further examine the feasibility of conducting an immunotoxicological assay for assessing humoral immunity in rats in

Gregory S Ladics; Charlene Smith; Glenn S Elliott; Theodore W Slone; Scott E Loveless

1998-01-01

254

TOXLINE (TOXICOLOGY INFORMATION ONLINE)  

EPA Science Inventory

TOXLINE? (TOXicology information onLINE) are the National Library of Medicines extensive collection of online bibliographic information covering the pharmacological, biochemical, physiological, and toxicological effects of drugs and other chemicals. TOXLINE and TOXLINE65 together...

255

Preclinical dose ranging studies for enzyme replacement therapy with idursulfase in a knock-out mouse model of MPS II.  

PubMed

Mucopolysaccharidosis II (MPS II; Hunter syndrome) is an X-linked metabolic disorder caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase (I2S), which catalyzes the catabolism of glycosaminoglycans (GAG) by cleaving the O-linked sulfate from dermatan sulfate and heparan sulfate. Recently, enzyme replacement therapy (ERT) with recombinant human I2S (Elaprase (idursulfase), Shire Human Genetic Therapies, Inc.), has been approved in the US and European Union for the treatment and management of MPS II. The purpose of the studies presented here was to describe some of the preclinical development of idursulfase using the I2S knock-out mouse model of MPS II designed to study the effect of dose and various dosing regimens of idursulfase on urine and tissue GAG levels. Urine and tissue samples were collected prior to idursulfase treatment and periodically throughout each study and analyzed for GAGs. The presence of anti-idursulfase antibodies in the mice serum after idursulfase use was also determined. Results showed that idursulfase, at several doses and at several dosing frequencies, caused a reduction in tissue and urine GAG levels in a dose-dependent manner. These studies also demonstrated that after IV administration, idursulfase is biologically active in the IdS-KO mouse model and is transported to key target tissues, reaching the lysosomes in an active form, and degrading the accumulated GAG. In conclusion, these results indicated that ERT with idursulfase produced in a human cell line could be useful in the treatment and management of MPS II, and were used in the design of clinical studies to evaluate the efficacy of idursulfase in MPS II patients. PMID:17459751

Garcia, Antony R; DaCosta, Jeffrey M; Pan, Jing; Muenzer, Joseph; Lamsa, Justin C

2007-06-01

256

Case study: the role of mechanistic network models in systems toxicology.  

PubMed

Twenty first century systems toxicology approaches enable the discovery of biological pathways affected in response to active substances. Here, we briefly summarize current network approaches that facilitate the detailed mechanistic understanding of the impact of a given stimulus on a biological system. We also introduce our network-based method with two use cases and show how causal biological network models combined with computational methods provide quantitative mechanistic insights. Our approach provides a robust comparison of the transcriptional responses in different experimental systems and enables the identification of network-based biomarkers modulated in response to exposure. These advances can also be applied to pharmacology, where the understanding of disease mechanisms and adverse drug effects is imperative for the development of efficient and safe treatment options. PMID:23933191

Hoeng, Julia; Talikka, Marja; Martin, Florian; Sewer, Alain; Yang, Xiang; Iskandar, Anita; Schlage, Walter K; Peitsch, Manuel C

2014-02-01

257

A new medium for Caenorhabditis elegans toxicology and nanotoxicology studies designed to better reflect natural soil solution conditions.  

PubMed

A new toxicity test medium for Caenorhabditis elegans is presented. The test solution is designed to provide a better representation of natural soil pore water conditions than currently available test media. The medium has a composition that can readily be modified to allow for studies of the influences of a range of environmentally relevant parameters on nematode biology and toxicology. Tests conducted in the new medium confirmed that nematodes' reproduction was possible at a range of solution pH levels, offering the potential to conduct toxicity studies under a variety of conditions. A test to establish silver nanoparticle and dissolved silver nitrate toxicity, a study type not feasible in M9 or agar media due to precipitation and nanoparticle agglomeration, indicated lower silver nanoparticle (median effective concentration [EC50] of 6.5?mg Ag/L) than silver nitrate (EC50 0.28?mg Ag/L) toxicity. Characterization identified stable nanoparticle behavior in the new test medium. PMID:23595813

Tyne, William; Lofts, Stephen; Spurgeon, David J; Jurkschat, Kerstin; Svendsen, Claus

2013-08-01

258

Possible incorporation of an immunotoxicological functional assay for assessing humoral immunity for hazard identification purposes in rats on standard toxicology study  

Microsoft Academic Search

The objective of this study was to examine the feasibility of conducting an immunotoxicological assay for assessing humoral immunity in rats on standard toxicology study. Male CD rats were untreated or dosed intraperitoneally daily for 30 or 90 days, excluding weekends, with vehicle or 2 mg\\/kg cyclophosphamide (CY). Six days prior to sacrifice, selected rats were injected intravenously with sheep

Gregory S. Ladics; Charlene Smith; Karen Heaps; Glenn S. Elliott; Theodore W. Slone; Scott E. Loveless

1995-01-01

259

The Study about the Degradation of Nitrobenzene by Domesticated Activated Sludge and the Initial Validation of Toxicology before and after the Degradation  

Microsoft Academic Search

In this paper, the domestication of the activated sludge by which nitrobenzene can be degraded in a relatively poor nutrition is studied. The ability of activated sludge degradation of nitrobenzene is studied by degradation kinetics. The toxicology validation about the effect of activated sludge degradation of nitrobenzene is preliminarily explored. The results show that: The nitrobenzene could be the sole

Yu-bin Ji; Jin-yu Zhou; Wen-lan Li; Chang-ru Xu; Xing-jie Zhu

2010-01-01

260

Pasteurization of bone for tumour eradication prior to reimplantation - An in vitro & pre-clinical efficacy study  

PubMed Central

Background & objectives: In current era of limb-salvage therapy, pasteurization of bone sarcomas is receiving growing attention as a potential extracorporeal treatment and cost-effective alternative to allografts and radiation before surgical reimplantation. Detailed in vitro and in vivo pre-clinical study to evaluate efficacy of pasteurization to eradicate malignant cells has not been reported yet. The present study was carried out to assess the efficacy of pasteurization to kill tumour cells both in vitro and in vivo. Methods: Surgically resected specimens of osteosarcomas (n=4) were cut into equal halves and one section was pasteurized by heating at 60°C to 65°C for 40 min. Paired samples before and after pasteurization were studied in vitro for DNA ploidy, evaluation of histological change and elimination of mitotic activity. These tissues were transplanted in immune-deficient NOD-SCID mice to evaluate effect on tumour-generating ability, presence of human nuclei, osteopontin and cytokine/chemokines released in tumour-transplanted mice. Results: Non-pasteurized tumour samples had viable tumour cells which exhibited significant growth in culture, increased proliferative ability and clonogenic potential while respective pasteurized tumour tissues did not grow in culture and did not exhibit clonogenicity. Flow cytometry revealed that propidium iodide positive dead cells increased significantly (P< 0.01) post pasteurization. Seven of 12 non-pasteurized tumour transplanted mice demonstrated tumour-forming ability as against 0 of 12 in pasteurized tumour transplanted mice. Solid tumour xenografts exhibited strong expression of anti-human nuclei and osteopontin by immunohistochemistry as well as secretary human interluekin-6 (IL-6) while pasteurized mice failed to express these markers. Interpretation & conclusions: This study has provided a basis to establish pasteurization as being efficacious in ensuring tumour eradication from resected bone tumour specimens. Pasteurized tumour bearing bone can thus safely be used to reconstruct large defects after tumour resection.

Kode, Jyoti; Taur, Prasad; Gulia, Ashish; Jambhekar, Nirmala; Agarwal, Manish; Puri, Ajay

2014-01-01

261

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...

262

Genetic toxicology: web resources  

Microsoft Academic Search

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®,

Robert R. Young

2002-01-01

263

75 FR 71132 - Availability of Draft Toxicological Profiles  

Federal Register 2010, 2011, 2012, 2013

...availability of the Toxicological Profile for Toxaphene (Update) and the Toxicological Profile...on studies about the health effects of toxaphene and trichlorobenzenes. ATSDR remains...tppubliccomments@cdc.gov. Please include toxaphene or trichlorobenzenes in the subject...

2010-11-22

264

Scanning Electron Microscope Studies of the Chemotherapeutic Control of Preclinical Cariogenic Infection.  

National Technical Information Service (NTIS)

In summary, the joint AFIP and NMRI studies in early enamel infection are producing the following results: (1) Information regarding variations in enamel topography, their precise locations, and varied susceptibility to demineralizing agents. This may hel...

S. Hoffman H. D. Tow J. S. Cole

1973-01-01

265

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

266

Pre-Clinical Atherosclerosis due to HIV Infection: Carotid Intima-Medial Thickness Measurements from the FRAM Study  

PubMed Central

Background Cardiovascular disease (CVD) is an increasing cause of morbidity and mortality in HIV-infected patients. However, it is controversial whether HIV infection contributes to accelerated atherosclerosis independent of traditional CVD risk factors. Methods Cross-sectional study of HIV-infected and control subjects without pre-existing CVD from the study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM) and the Multi-Ethnic Study of Atherosclerosis (MESA). Pre-clinical atherosclerosis was assessed by carotid intima-medial thickness (IMT) measurements in the internal/bulb and common regions in HIV-infected and control subjects after adjusting for traditional CVD risk factors. Results For internal carotid, mean IMT was 1.17±0.50mm for HIV-infected participants and 1.06±0.58mm for controls (p<0.0001). After multivariable adjustment for demographic characteristics, the mean difference of HIV-infected vs. controls was +0.188mm (95%CI 0.113-0.263, p<0.0001). Further adjustment for traditional CVD risk factors modestly attenuated the HIV association (+0.148mm, 95%CI 0.072-0.224, p=0.0001). For the common carotid, HIV infection was independently associated with greater IMT (+0.033mm, 95%CI 0.010, 0.056, p=0.005). The association of HIV infection with IMT was similar to that of smoking which was also associated with greater IMT (internal +0.173mm, common +0.020mm). Conclusions Even after adjustment for traditional CVD risk factors, HIV infection was accompanied by more extensive atherosclerosis measured by IMT. The stronger association of HIV infection with IMT in the internal/bulb region compared to the common carotid may explain previous discrepancies in the literature. The association of HIV infection with IMT was similar to that of traditional CVD risk factors, such as smoking.

Grunfeld, C.; Delaney, J.A.C.; Wanke, C.; Currier, J.S.; Scherzer, R.; Biggs, M. L.; Tien, P.; Shlipak, M.; Sidney, S.; Polak, J.F.; O'Leary, D.; Bacchetti, P.; Kronmal, R.

2010-01-01

267

Preclinical studies on the radioprotective efficacy and pharmacokinetics of subcutaneously administered amifostine.  

PubMed

The radioprotective effects and pharmacokinetics of subcutaneously (SC) administered amifostine have been investigated in animal studies. Studies in rats using a single dose of amifostine showed that SC administration gave protection from radiation-induced mucositis that is at least equivalent to that achieved by intravenous administration of the drug. These studies also indicate that tissue levels of the active metabolite WR-1065 correlated better with the radioprotective effects of amifostine than do plasma WR-1065 levels. Multiple-dose studies in rats show radioprotective effects equal to or greater than those obtained with intravenous dosing in the setting of fractionated irradiation. In addition, there is no evidence of drug accumulation in either normal or tumor tissue, with tumor WR-1065 levels peaking just above the limits of quantitation during treatment. Preliminary data from studies of SC amifostine in monkeys indicate a plasma pharmacokinetic profile similar to that reported earlier in humans. Tissue WR-1065 levels were higher at 30 minutes after SC dosing than they were after intravenous dosing and were comparable for the two routes at 60 minutes. PMID:12577236

Cassatt, David R; Fazenbaker, Christine A; Kifle, Gizachew; Bachy, Christine M

2002-12-01

268

Mesenchymal stem cell therapy for salivary gland dysfunction and xerostomia: a systematic review of preclinical studies.  

PubMed

The most severe forms of xerostomia and salivary gland dysfunction, as well as a severely reduced quality of life, are seen in Sjögren syndrome (SS) and after radiotherapy for head and neck cancer. For both conditions, no effective regenerative therapies yet exist. Thus, the aim of this article was to assess, through systematic review, the potential benefit of mesenchymal stem cell (MSC) therapy in radiation-induced and SS-related salivary gland dysfunction and xerostomia. We searched PubMed/MEDLINE, Embase, Web of Science, the Cochrane Database of Systematic Reviews, the World Health Organization Clinical Trials Registry Platform, and Google Scholar. We identified 6 separate study comparisons eligible for inclusion. Owing to the limited number of studies, we conclude that more randomized, adequately powered clinical trials are needed to validate the potential beneficial effect of MSCs on salivary gland dysfunction and xerostomia. Nonetheless, the preliminary studies identified in the present review were encouraging for further research. PMID:24528792

Jensen, David Hebbelstrup; Oliveri, Roberto Stefan; Trojahn Kølle, Stig-Frederik; Fischer-Nielsen, Anne; Specht, Lena; Bardow, Allan; Buchwald, Christian

2014-03-01

269

Task III Preclinical Five Daily Dose Local Vasotoxicity Study of Acodazole (NSC-305884) in Rabbits.  

National Technical Information Service (NTIS)

A five daily dose vasotoxicity study was conducted to evaluate the local vasotoxicity resulting from five daily intravenous injections of NSC-305884 in the lateral marginal ear vein of the left rabbit ear. Doses administered, 0.97, 9.72 and 29.16 mg/kg/da...

J. M. Morgan T. B. Barnes G. D. Taylor J. E. Whalan M. D. Kastello

1983-01-01

270

Preclinical development of keliximab, a Primatized™ anti-CD4 monoclonal antibody, in human CD4 transgenic mice: characterization of the model and safety studies  

Microsoft Academic Search

The preclinical safety assessment of biopharmaceuticals necessitates that studies be conducted in species in which the products are pharmacologically active. Monoclonal anti-bodies are a promising class ofbiopharmaceuticals for many disease indications; however, by design, these agents tend to have limited species cross-reactivity and tend to only be active in primates. Keliximab is a human-cynomolgus monkey chimeric (Primatized&) monoclonal antibody with

P J Bugelskil; D J Herzykl; S. Rehm; A. G. Harmsen; E. V. Gore; D. M. Williams; B. E. Maleeff; A. M. Badger; A. Truneh; S R OBrien; R A Macial; P. J. Wier; D. G. Morgan; T. K. Hart

2000-01-01

271

Preclinical studies of the proteasome inhibitor bortezomib in malignant pleural mesothelioma  

Microsoft Academic Search

Malignant pleural mesothelioma (MPM) is a highly lethal neoplasm that is resistant to chemotherapy. Bortezomib is an FDA-approved\\u000a proteasome inhibitor that is currently under clinical investigation in multiple neoplasms but has not been studied extensively\\u000a in MPM. In this report, we determine the biological and molecular response of cultured MPM cells to bortezomib alone and in\\u000a combination with cisplatin or

Gavin J. Gordon; Madhubalan Mani; Gautam Maulik; Lipi Mukhopadhyay; Beow Y. Yeap; Hedy L. Kindler; Ravi Salgia; David J. Sugarbaker; Raphael Bueno

2008-01-01

272

In Situ and Ex Vivo Nasal Models for Preclinical Drug Development Studies  

Microsoft Academic Search

Advances in drug delivery research are to a reasonable extent dependent on the use of innovative experimental models. As a\\u000a result of many experimental, methodological, and ethical limitations associated with the use of the human species, animal\\u000a models are routinely used for drug delivery studies, especially during early stages of drug development. The use of excised\\u000a and cultured human or

Remigius U. Agu; Michael I. Ugwoke

273

Mentalizing in preclinical Huntington's disease: an fMRI study using cartoon picture stories.  

PubMed

Huntington's disease (HD) is an autosomal dominant degenerative brain disorder that is characterized by motor, cognitive and affective symptoms. Previous research has shown that patients with HD, similar to patients with schizophrenia, are impaired in their ability to appreciate the mental states of others. Functional brain imaging studies have shown that patients with schizophrenia underactivate the neural network involved in mentalizing, and that deviant patterns of brain activation are also present in individuals at high risk of developing a psychotic disorder. Accordingly, the present study sought to examine the brain activation in premanifest mutation carriers for HD. Thirty premanifest mutation carriers (13 males) defined by a positive gene test and absence of unequivocal HD symptoms ("pre-HD") performed a cartoon mentalizing task during functional brain imaging. For comparison, a group of 26 healthy controls took part in the study. BOLD responses revealed that pre-HD subjects activated the mentalizing network comprising prefrontal, temporoparietal and parietal brain regions during task performance. A comparison between pre-HD patients and healthy controls revealed no significant activation differences. Premanifest mutation carriers of HD activated the neural network involved in mentalizing similar to healthy control subjects. This suggests that impaired mentalizing emerges with the clinical manifestation of the disease, but is not necessarily part of the pre-manifest stage. PMID:23179063

Saft, Carsten; Lissek, Silke; Hoffmann, Rainer; Nicolas, Volkmar; Tegenthoff, Martin; Juckel, Georg; Brüne, Martin

2013-06-01

274

The role of orbitofrontal cortex in drug addiction: a review of preclinical studies  

PubMed Central

Studies using brain imaging methods have shown that neuronal activity in the orbitofrontal cortex, a brain area thought to promote the ability to control behavior according to likely outcomes or consequences, is altered in drug addicts. These human imaging findings have led to the hypothesis that core features of addiction like compulsive drug use and drug relapse are mediated in part by drug-induced changes in orbitofrontal function. Here, we discuss results from laboratory studies using rats and monkeys on the effect of drug exposure on orbitofrontal-mediated learning tasks and on neuronal structure and activity in orbitofrontal cortex. We also discuss results from studies on the role of the orbitofrontal cortex in drug self-administration and relapse. Our main conclusion is that while there is clear evidence that drug exposure impairs orbitofrontal-dependent learning tasks and alters neuronal activity in orbitofrontal cortex, the precise role these changes play in compulsive drug use and relapse has not yet been established.

Schoenbaum, Geoffrey; Shaham, Yavin

2008-01-01

275

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

276

Application of Emerging Technologies in Toxicology and Safety Assessment: Regulatory Perspectives  

Microsoft Academic Search

Emerging technologies applied in the regulatory field encompass a group of technologies that are used in addition to or in replacement of the standard toxicology studies conducted to support an Investigational New Drug Application (IND) or New Drug Application (NDA). The standard package includes general toxicology studies of various duration, safety pharmacology studies, genetic toxicology studies, and reproductive toxicology studies.

John K. Leighton

2005-01-01

277

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

278

Neural Stem Cell-Mediated Enzyme-Prodrug Therapy for Glioma: Preclinical Studies  

PubMed Central

High-grade gliomas are extremely difficult to treat because they are invasive and therefore are not curable by surgical resection; the toxicity of currently 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 that can target enzyme/prodrug therapy selectively to tumors. We have used a cytosine deaminase (CD)-expressing clonal human NSC line, HB1.F3.CD, to home to gliomas in mice and locally convert the tumor-localized prodrug 5-fluorocytosine to the active chemotherapeutic 5-fluorouracil. In vitro studies confirmed that the NSCs have normal karyotype, tumor tropism, and CD expression, indicating that these cells are genetically and functionally stable. In vivo biodistribution studies demonstrated that these NSCs retained tumor tropism, even in mice pre-treated 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 in 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 approximately 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, non-toxic and effective in mice. These data have led to approval of a first-inhuman study of an allogeneic NSC-mediated enzyme/prodrug targeted cancer therapy in patients with recurrent high-grade glioma.

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

2013-01-01

279

Masitinib antagonizes ATP-binding cassette subfamily C member 10-mediated paclitaxel resistance: a preclinical study.  

PubMed

Paclitaxel displays clinical activity against a wide variety of solid tumors. However, resistance to paclitaxel significantly attenuates the response to chemotherapy. The ABC transporter subfamily C member 10 (ABCC10), also known as multidrug resistance protein 7 (MRP7) efflux transporter, is a major mediator of paclitaxel resistance. In this study, we show that masitinib, a small molecule stem-cell growth factor receptor (c-Kit) tyrosine kinase inhibitor, at nontoxic concentrations, significantly attenuates paclitaxel resistance in HEK293 cells transfected with ABCC10. Our in vitro studies indicated that masitinib (2.5 ?mol/L) enhanced the intracellular accumulation and decreased the efflux of paclitaxel by inhibiting the ABCC10 transport activity without altering the expression level of ABCC10 protein. Furthermore, masitinib, in combination with paclitaxel, significantly inhibited the growth of ABCC10-expressing tumors in nude athymic mice in vivo. Masitinib administration also resulted in a significant increase in the levels of paclitaxel in the plasma, tumors, and lungs compared with paclitaxel alone. In conclusion, the combination of paclitaxel and masitinib could serve as a novel and useful therapeutic strategy to reverse paclitaxel resistance mediated by ABCC10. PMID:24431074

Kathawala, Rishil J; Sodani, Kamlesh; Chen, Kang; Patel, Atish; Abuznait, Alaa H; Anreddy, Nagaraju; Sun, Yue-Li; Kaddoumi, Amal; Ashby, Charles R; Chen, Zhe-Sheng

2014-03-01

280

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

281

Hydration with Saline Decreases Toxicity of Mice Injected With Calcitriol in Preclinical Studies  

PubMed Central

The effectiveness of saline injection in reducing the toxicity profile of calcitriol when coadministered in mice was evaluated. Mortality was used as an end point to study the toxic effects of calcitriol; the relative risk of mortality in mice injected with saline was evaluated from our previously published animal experiments. We discovered that coadministration with 0.25 mL normal saline solution injected intraperitoneally is associated with a lower mortality rate than calcitriol given alone. The estimated relative risk of mortality was 0.0789 (95% confidence interval, 0.0051–1.22; z = 1.82; P = 0.070) when saline is administered with calcitriol compared to calcitriol alone. There was a reduction in serum calcium levels in mice that received saline (11.4 ± 0.15 mg/dL) compared to mice that did not receive saline (12.42 ± 1.61 mg/dL). Hydration with saline seems to reduce mortality and toxicity in mice receiving calcitriol. Given the decrease in mortality rates, intraperitoneal injections of saline should be considered in studies involving mice receiving injections of calcitriol.

Azari, Amir A; Kanavi, Mozhgan R.; Darjatmoko, Soesiawati R.; Lee, Vivian; Kim, KyungMann; Potter, Heather D.; Albert, Daniel M.

2014-01-01

282

Toxicological Study of Ocimum sanctum Linn Leaves: Hematological, Biochemical, and Histopathological Studies.  

PubMed

The present study was aimed to study the acute and subacute toxicity studies with orally administered 50% ethanolic leaves extract of Ocimum sanctum Linn (OSE). In acute toxicity tests, four groups of mice (n = 6/group/sex) were orally treated with doses of 200, 600, and 2000?mg/kg, and general behavior, adverse effects, and mortality were recorded for up to 14 days. In subacute toxicity study, rats received OSE by gavage at the doses of 200, 400, and 800?mg/kg/day (n = 6/group/sex) for 28 days, and biochemical, hematological, and histopathological changes in tissues (liver, kidney, spleen, heart, and testis/ovary) were determined. OSE did not produce any hazardous symptoms or death and CNS and ANS toxicities in the acute toxicity test. Subacute treatment with OSE did not show any change in body weight, food and water consumption, and hematological and biochemical profiles. In addition, no change was observed both in macroscopic and microscopic aspects of vital organs in rats. Our result showed that Ocimum sanctum extract could be safe for human use. PMID:24616736

Gautam, M K; Goel, R K

2014-01-01

283

Specific effects of bortezomib against experimental malignant pleural effusion: a preclinical study  

PubMed Central

Background We have previously shown that nuclear factor (NF)-?B activation of mouse Lewis lung carcinoma (LLC) specifically promotes the induction of malignant pleural effusions (MPE) by these cells. In the present studies we hypothesized that treatment of immunocompetent mice with bortezomib tailored to inhibit cancer cell NF-?B activation and not proliferation specifically inhibits MPE formation by LLC cells. Results Treatment of LLC cells with low concentrations of bortezomib (100 ng/ml) inhibited NF-?B activation and NF-?B-dependent transcription, but not cellular proliferation. Bortezomib treatment of immunocompetent C57BL/6 mice bearing LLC-induced subcutaneous tumors and MPEs significantly blocked tumor-specific NF-?B activation. However, bortezomib treatment did not impair subcutaneous LLC tumor growth, but was effective in limiting LLC-induced MPE. This specific effect was evidenced by significant reductions in effusion accumulation and the associated mortality and was observed with both preventive (beginning before MPE formation) and therapeutic (beginning after MPE establishment) bortezomib treatment. The favorable impact of bortezomib on MPE was associated with suppression of cardinal MPE-associated phenomena, such as inflammation, vascular hyperpermeability, and angiogenesis. In this regard, therapeutic bortezomib treatment had identical favorable results on MPE compared with preventive treatment, indicating that the drug specifically counteracts effusion formation. Conclusions These studies indicate that proteasome inhibition tailored to block NF-?B activation of lung adenocarcinoma specifically targets the effusion-inducing phenotype of this tumor. Although the drug has limited activity against advanced solid lung cancer, it may prove beneficial for patients with MPE.

2010-01-01

284

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

285

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...

286

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...

287

Recent Advances in Particulate Matter and Nanoparticle Toxicology: A Review of the In Vivo and In Vitro Studies  

PubMed Central

Epidemiological and clinical studies have linked exposure to particulate matter (PM) to adverse health effects, which may be registered as increased mortality and morbidity from various cardiopulmonary diseases. Despite the evidence relating PM to health effects, the physiological, cellular, and molecular mechanisms causing such effects are still not fully characterized. Two main approaches are used to elucidate the mechanisms of toxicity. One is the use of in vivo experimental models, where various effects of PM on respiratory, cardiovascular, and nervous systems can be evaluated. To more closely examine the molecular and cellular mechanisms behind the different physiological effects, the use of various in vitro models has proven to be valuable. In the present review, we discuss the current advances on the toxicology of particulate matter and nanoparticles based on these techniques.

Nemmar, Abderrahim; Holme, J?rn A.; Rosas, Irma; Schwarze, Per E.

2013-01-01

288

Novel transdermal delivery of Timolol maleate using sugar esters: preclinical and clinical studies.  

PubMed

The feasibility of matrix controlled transdermal patch based on sugar fatty acid ester (SE) as penetration and absorption enhancer containing Timolol maleate (TM) was investigated. The influence of fatty acid type, chain length and hydrophile-lipophile balance (HLB) on the in vitro drug release as well as its permeation across hairless rat skin were studied and compared aiming to select a patch formula for clinical performance. Skin irritation induced by SE patch was evaluated by visual scoring, color reflectance measurements and non-invasive transepidermal water loss (TEWL) technique. The results indicated that among different SEs tried, laurate SE with shorter fatty acid chain length and higher HLB value significantly increased the amount of TM liberated from the patch (99+/-2.1%) and its permeation across rat skin (86+/-4.3%). The total drug permeation and flux values were approximately 5-fold greater compared to SE free patch. The extent of absorption of TM-SE patch expressed by AUC was 64% larger as compared to the oral solution with steady plasma concentration over 18 h and relative bioavailability (F(rel)) of 163%. The developed patch was well tolerated by all the subjects with only moderate skin irritation, which was recovered in 24h after patch removal. The results are very encouraging and offer an alternative approach to maintain higher, prolonged and controlled blood level profile of the drug over 18-24h. PMID:19126429

El-Laithy, Hanan M

2009-05-01

289

GABAergic contributions to alcohol responsivity during adolescence: insights from preclinical and clinical studies.  

PubMed

There is a considerable body of literature demonstrating that adolescence is a unique age period, which includes rapid and dramatic maturation of behavioral, cognitive, hormonal and neurobiological systems. Most notably, adolescence is also a period of unique responsiveness to alcohol effects, with both hyposensitivity and hypersensitivity observed to the various effects of alcohol. Multiple neurotransmitter systems are undergoing fine-tuning during this critical period of brain development, including those that contribute to the rewarding effects of drugs of abuse. The role of developmental maturation of the ?-amino-butyric acid (GABA) system, however, has received less attention in contributing to age-specific alcohol sensitivities. This review integrates GABA findings from human magnetic resonance spectroscopy studies as they may translate to understanding adolescent-specific responsiveness to alcohol effects. Better understanding of the vulnerability of the GABA system both during adolescent development, and in psychiatric conditions that include alcohol dependence, could point to a putative mechanism, boosting brain GABA, that may have increased effectiveness for treating alcohol use disorders. PMID:24631274

Silveri, Marisa M

2014-08-01

290

Receptor-selective mutants of tumour necrosis factor in the therapy of cancer: preclinical studies.  

PubMed

The use of TNF-mutants that are selective agonists of the TNF-R55 is one strategy that is being explored to broaden the therapeutic margin of TNF. Several problems still have to be overcome before they can be used in clinical trials. Regarding the sensitizing effect of some infections and some tumours, we identified IFN-gamma as a mediator in BCG- but not in tumour-induced sensitization. In both models, the vessel wall is most probably the key tissue as alpha-LFA-1 antibodies could protect against lethality. Studies in primates showed that an unexpected feature, namely, the longer half-life of such mutants, might interfere with this strategy. Recent observations also indicate that the mechanism of tolerance-induction, another way to separate antitumour and toxic effects of TNF, might reside in the functional ablation of the TNF-R75. Using IL-60/0 knockout mice, we could not find any causal role for IL-6 in TNF-mediated lethality, this in contrast to results obtained previously with neutralizing antibodies. Finally, we identified the acute phase protein alpha 1-acid glycoprotein as a protein with protective properties towards TNF-induced lethality and liver damage. PMID:7895324

Brouckaert, P; Ameloot, P; Cauwels, A; Everaerdt, B; Libert, C; Takahashi, N; Van Molle, W; Fiers, W

1994-08-01

291

Silver nanoparticle/chitosan oligosaccharide/poly(vinyl alcohol) nanofibers as wound dressings: a preclinical study  

PubMed Central

In this study, a mixture of poly(vinyl alcohol) (PVA) and chitosan oligosaccharides (COS) was electrospun with silver nanoparticles (AgNPs) to produce fibrous mats for use in wound healing. The AgNPs were reduced by COS prior to electrospinning or Ag+ was reduced via ultraviolet irradiation in nanofibers. The morphologies of the PVA/COS/AgNO3 and PVA/COS-AgNP nanofibers were analyzed by scanning electron microscopy. Formation of the AgNPs was investigated by field emission transmission electron microscopy, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. We also evaluated the biocompatibility of the nanofibers, particularly their cytotoxicity to human skin fibroblasts and potential to cause primary skin irritation. The in vitro antibacterial activity and in vivo wound healing capacity of the nanofibers were also investigated. The nanofibers had a smooth surface with an average diameter of 130–192 nm. The diameters of the AgNPs were in the range of 15–22 nm. The nanofibers significantly inhibited growth of Escherichia coli and Staphylococcus aureus bacteria. PVA/COS-AgNP nanofibers accelerated the rate of wound healing over that of the control (gauze). The results of our in vitro and in vivo animal experiments suggest that PVA/COS-AgNP nanofibers should be of greater interest than PVA/COS/AgNO3 nanofibers for clinical use as a bioactive wound dressing.

Li, Chenwen; Fu, Ruoqiu; Yu, Caiping; Li, Zhuoheng; Guan, Haiyan; Hu, Daqiang; Zhao, Dehua; Lu, Laichun

2013-01-01

292

Ovarian hyperstimulation syndrome inhibition by targeting VEGF, COX-2 and Calcium pathways: a preclinical randomized study.  

PubMed

Abstract Objective: The efficacy of vascular endothelial growth factor (VEGF), COX-2, calcium and aromatase inhibitors in an ovarian hyperstimulation syndrome (OHSS) rat model was tested. Methods: One hundred and eight female Wistar rats were randomly divided in nine groups. The control group received saline, while the OHSS group received rec-FSH for 4 consecutive days. The other seven groups received rec-FSH (4d) and Bevacizumab twice, Parecoxib daily, Verapamil daily, Parecoxib daily and Bevacizumab twice, Verapamil daily and Bevacizumab twice, Parecoxib and Verapamil daily, Letrozole and Meloxicam daily, respectively. All groups received also hCG at the 5th day. Results: All intervention groups were characterized by reduced vascular permeability compared to the OHSS group, which in the groups of Verapamil (Calcium inhibition) and Parecoxib?+?Verapamil (COX-2?+?Calcium inhibition) presented significant statistical difference. The Verapamil group showed the lowest corpus luteum formation, while the Parecoxib (COX-2 inhibition), the Parecoxib?+?Verapamil (COX-2?+?Calcium inhibition), the Bevacizumab?+?Parecoxib (VEGF?+?COX-2 inhibition) and the Bevacizumab?+?Verapamil (VEGF?+?Calcium inhibition) groups were also characterized by lower corpus luteum numbers compared to the OHSS group. Furthermore, lower graafian follicle formation was observed in the above groups, while the ovarian weight and the hormonal profile were not significantly affected. Conclusions: Studying the different check points of the VEGF pathway, we conclude that targeting calcium pathways could be beneficial for the vascular permeability control in an OHSS animal model. PMID:24819316

Kitsou, Chrysoula; Kosmas, Ioannis; Lazaros, Leandros; Hatzi, Elissavet; Euaggelou, Aggelos; Mynbaev, Ospan; Tournaye, Herman; Prapas, Nikolaos; Prapas, Ioannis; Zikopoulos, Konstantinos; Galani, Vasiliki; Georgiou, Ioannis

2014-08-01

293

Preclinical studies of vascular acting photosensitizer bacteriopheophorbide for the treatment of prostate cancer  

NASA Astrophysics Data System (ADS)

Photodynamic therapy (PDT) mediated with vascular acting photosensitizer pd-bacteriopheophorbide (Tookad), is investigated as an alternative modality for the total ablation of prostate cancer. In vivo normal canine prostate is used as the animal model. Interstitial PDT was performed by irradiating the surgically exposed prostates with a diode laser (763 nm, 150 mW/cm) to activate the IV infused photosensitizer drug. The prostate and its adjacent tissues were harvested and subjected to histopathological examination. At one-week post PDT, the animals recovered well with little or no urethral complications. Prostatic urethra and prostate adjacent tissues (bladder and underlying colon) were well preserved. PDT induced prostate lesions were characterized by marked hemorrhagic necrosis. Prostate lesions could be detected by MRI scan as early as 48 h post PDT. Maximum lesion size of 1.5 cm3 and 2.9 cm3 could be achieved at 50 J/cm and 100 J/cm, respectively, with interstitial treatment using a single 1-cm diffuser fiber, suggesting the Tookad-PDT is very effective in ablating prostatic tissue. Pharmacokinetic studies show that the photosensitizer is cleared rapidly from the circulation. In conclusion, the novel photosensitizer Tookad mediated PDT may provide an effective alternative to treat localized prostate cancer.

Hetzel, Fred W.; Chen, Qun; Luck, David; Beckers, Jill; Huang, Zheng

2004-06-01

294

Preclinical episodes of orofacial pain symptoms and their association with healthcare behaviors in the OPPERA prospective cohort study.  

PubMed Central

The course of preclinical pain symptoms sheds light on the etiology and prognosis of chronic pain. We aimed to quantify rates of developing initial- and recurrent-symptoms of painful temporomandibular disorder (TMD) and to evaluate associations with health behaviors. In the OPPERA prospective cohort study, 2,719 people aged 18-44 years with lifetime absence of TMD when enrolled completed 25,103 quarterly (three-monthly) questionnaires during amedian 2.3-year follow-up period. Questionnaires documented TMD symptom episodes, headache, other body pain, health care attendance and analgesic usage and. Kaplan-Meier methods for clustered data estimated symptom-free survival time. Multivariable models assessed demographic variation in TMD symptom rates and evaluated associations with healthcare and analgesic use. One third of people developed TMD symptoms and for one quarter of symptomatic episodes, pain intensity was severe. Initial TMD symptoms developed at anannual rate of 18.8 episodes per 100 people. The annual rate more than doubled for first-recurrence and doubled again for second-or-subsequent recurrence such that, one year after first recurrence, 71% of people experienced second recurrence. The overall rate increased with age and was greater in African-Americans and lower in Asians relative to Whites. The probability of TMD symptoms was strongly associated with concurrent episodes of headache and body pain and with past episodes of TMD symptoms. Episodes of TMD symptoms, headache and body pain were associated with increases of ~10% in probability of analgesic usage and healthcare attendance. Yet, even when TMD, headache and body pain occurred concurrently, 27% of people neither attended healthcare nor used analgesics.

Slade, Gary D.; Sanders, Anne E.; Bair, Eric; Brownstein, Naomi; Dampier, Dawn; Knott, Charles; Fillingim, Roger; Maixner, William O.; Smith, Shad; Greenspan, Joel; Dubner, Ron; Ohrbach, Richard

2013-01-01

295

A transplantable TH-MYCN transgenic tumor model in C57Bl/6 mice for preclinical immunological studies in neuroblastoma.  

PubMed

Current multimodal treatments for patients with neuroblastoma (NBL), including anti-disialoganglioside (GD2) monoclonal antibody (mAb) based immunotherapy, result in a favorable outcome in around only half of the patients with advanced disease. To improve this, novel immunocombinational strategies need to be developed and tested in autologous preclinical NBL models. A genetically well-explored autologous mouse model for NBL is the TH-MYCN model. However, the immunobiology of the TH-MYCN model remains largely unexplored. We developed a mouse model using a transplantable TH-MYCN cell line in syngeneic C57Bl/6 mice and characterized the immunobiology of this model. In this report, we show the relevance and opportunities of this model to study immunotherapy for human NBL. Similar to human NBL cells, syngeneic TH-MYCN-derived 9464D cells endogenously express the tumor antigen GD2 and low levels of MHC Class I. The presence of the adaptive immune system had little or no influence on tumor growth, showing the low immunogenicity of the NBL cells. In contrast, depletion of NK1.1+ cells resulted in enhanced tumor outgrowth in both wild-type and Rag1(-/-) mice, showing an important role for NK cells in the natural anti-NBL immune response. Analysis of the tumor infiltrating leukocytes ex vivo revealed the presence of both tumor associated myeloid cells and T regulatory cells, thus mimicking human NBL tumors. Finally, anti-GD2 mAb mediated NBL therapy resulted in ADCC in vitro and delayed tumor outgrowth in vivo. We conclude that the transplantable TH-MYCN model represents a relevant model for the development of novel immunocombinatorial approaches for NBL patients. PMID:24038106

Kroesen, Michiel; Nierkens, Stefan; Ansems, Marleen; Wassink, Melissa; Orentas, Rimas J; Boon, Louis; den Brok, Martijn H; Hoogerbrugge, Peter M; Adema, Gosse J

2014-03-15

296

Combined effects of bevacizumab with erlotinib and irradiation: a preclinical study on a head and neck cancer orthotopic model  

PubMed Central

Clinical benefit has been demonstrated in patients with head and neck tumours receiving an anti-epidermal growth factor receptor (EGFR) agent in combination with radiotherapy (RT). Recent preclinical and clinical studies suggest beneficial effects from combining anti-angiogenic drugs with RT. To investigate the effect of combining these approaches, we evaluated in vivo the anti-tumour efficacy of the anti-angiogenic compound bevacizumab, a highly specific monoclonal antibody directed against the vascular endothelial growth factor (VEGF), erlotinib, an EGFR tyrosine kinase inhibitor, and irradiation given alone and in combination. Investigations were performed using a VEGF-secreting human head and neck tumour cell line, CAL33, with a high EGFR content, injected as orthotopic xenografts into the mouth floor of nude mice. Three days after tumour cell injection, bevacizumab (5?mg?kg?1, 5 days a week, i.p.), erlotinib (100?mg?kg?1, 5 days a week, orally) and irradiation (6?Gy, 3 days a week) were administered alone and in combination for 10 days. As compared with the control, concomitant administration of drugs produced a marked and significant supra-additive decrease in tumour mass; the addition of irradiation almost completely abolished tumour growth. The drug association markedly reduced the number of metastatic nodes and the triple combination significantly reduced the total number of pathologically positive lymph nodes as compared with controls. The RT-induced proliferation, reflected by Ki67 labelling, was reduced to control level with the triple combination. Radiotherapy induced a strong and very significant increase in tumour angiogenesis, which was no longer observed when combined with erlotinib and bevacizumab. The efficacy of the combination of bevacizumab+erlotinib and RT may be of clinical importance in the management of head and neck cancer patients.

Bozec, A; Sudaka, A; Fischel, J-L; Brunstein, M-C; Etienne-Grimaldi, M-C; Milano, G

2008-01-01

297

Combined analysis of pharmacokinetic and efficacy data of preclinical studies with statins markedly improves translation of drug efficacy to human trials.  

PubMed

Correct prediction of human pharmacokinetics (PK) and the safety and efficacy of novel compounds based on preclinical data, is essential but often fails. In the current study, we aimed to improve the predictive value of ApoE*3Leiden (E3L) transgenic mice regarding the cholesterol-lowering efficacy of various statins in humans by combining pharmacokinetic with efficacy data. The efficacy of five currently marketed statins (atorvastatin, simvastatin, lovastatin, pravastatin, and rosuvastatin) in hypercholesterolemic patients (low-density lipoprotein ? 160 mg/dl) was ranked based on meta-analysis of published human trials. Additionally, a preclinical combined PK efficacy data set for these five statins was established in E3L mice that were fed a high-cholesterol diet for 4 weeks, followed by 6 weeks of drug intervention in which statins were supplemented to the diet. Plasma and tissue levels of the statins were determined on administration of (radiolabeled) drugs (10 mg/kg p.o.). As expected, all statins reduced plasma cholesterol in the preclinical model, but a direct correlation between cholesterol lowering efficacy of the different statins in mice and in humans did not reach statistical significance (R(2) = 0.11, P < 0.57). It is noteworthy that, when murine data were corrected for effective liver uptake of the different statins, the correlation markedly increased (R(2) = 0.89, P < 0.05). Here we show for the first time that hepatic uptake of statins is related to their cholesterol-lowering efficacy and provide evidence that combined PK and efficacy studies can substantially improve the translational value of the E3L mouse model in the case of statin treatment. This strategy may also be applicable for other classes of drugs and other preclinical models. PMID:24049060

van de Steeg, E; Kleemann, R; Jansen, H T; van Duyvenvoorde, W; Offerman, E H; Wortelboer, H M; Degroot, J

2013-12-01

298

Systematic reviews and meta-analyses of preclinical studies: publication bias in laboratory animal experiments.  

PubMed

In 2006, Peters et al. identified 86 systematic reviews (SRs) of laboratory animal experiments (LAEs). They found 46 LAE meta-analyses (MAs), often of poor quality. Six of these 46 MAs tried to assess publication bias. Publication bias is the phenomenon of an experiment's results determining its likelihood of publication, often over-representing positive findings. As such, publication bias is the Achilles heel of any SR. Since researchers increasingly become aware of the fact that SRs directly support the 'three Rs', we expect the number of SRs of LAEs will sharply increase. Therefore, it is useful to see how publication bias is dealt with. Our objective was to identify all SRs and MAs of LAEs where the purpose was to inform human health published between July 2005 and 2010 with special attention to MAs' quality features and publication bias. We systematically searched Medline, Embase, Toxline and ScienceDirect from July 2005 to 2010, updating Peters' review. LAEs not directly informing human health or concerning fundamental biology were excluded. We found 2780 references of which 163 met the inclusion criteria: 158 SRs, of which 30 performed an MA, and five MAs without an SR. The number of SRs roughly doubled every three years since 1997. The number of MAs roughly doubled every five years since 1999. Compared with before July 2005, more MAs were preceded by SR and reported on (quality) features of included studies and heterogeneity. A statistically significant proportion of MAs considered publication bias (26/35) and tried to formally assess it (21/35). PMID:21737463

Korevaar, D A; Hooft, L; ter Riet, G

2011-10-01

299

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

PubMed Central

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 of lower limb ischaemia before CPB. Main outcome measures Troponin I, glial protein S?100B, lactate concentrations, load?independent indices (conductance catheter) of systolic and diastolic function, and pulmonary resistance and compliance were measured before and for 6?h after CPB. Results Troponin I increased after CPB in both groups but during reperfusion the rIPC group had lower concentrations than controls (mean area under the curve ?57.3 (SEM 7.3) v 89.0 (11.6)?ng·h/ml, p??=??0.02). Lactate increased after CPB in both groups but during reperfusion the control group had significantly more prolonged hyperlactataemia (p??=??0.04). S?100B did not differ between groups. Indices of ventricular function did not differ. There was a tendency to improved lung compliance (p??=??0.07), and pulmonary resistance changed less in the rIPC than in the control group during reperfusion (p??=??0.02). Subsequently, peak inspiratory pressure was lower (p??=??0.001). Conclusion rIPC significantly attenuated clinically relevant markers of myocardial and pulmonary injury after CPB. Transient limb ischaemia as an rIPC stimulus has potentially important clinical applications.

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

2006-01-01

300

Molecular actions and therapeutic potential of lithium in preclinical and clinical studies of CNS disorders  

PubMed Central

Lithium has been used clinically to treat bipolar disorder for over half a century, and remains a fundamental pharmacological therapy for patients with this illness. Although lithium’s therapeutic mechanisms are not fully understood, substantial in vitro and in vivo evidence suggests that it has neuroprotective/neurotrophic properties against various insults, and considerable clinical potential for the treatment of several neurodegenerative conditions. Evidence from pharmacological and gene manipulation studies support the notion that glycogen synthase kinase-3 inhibition and induction of brain-derived neurotrophic factor-mediated signaling are lithium’s main mechanisms of action, leading to enhanced cell survival pathways and alteration of a wide variety of downstream effectors. By inhibiting N-methyl-D-aspartate receptor-mediated calcium influx, lithium also contributes to calcium homeostasis and suppresses calcium-dependent activation of pro-apoptotic signaling pathways. In addition, lithium decreases inositol 1,4,5-trisphosphate by inhibiting phosphoinositol phosphatases, a process recently identified as a novel mechanism for inducing autophagy. Through these mechanisms, therapeutic doses of lithium have been demonstrated to defend neuronal cells against diverse forms of death insults and to improve behavioral as well as cognitive deficits in various animal models of neurodegenerative diseases, including stroke, amyotrophic lateral sclerosis, fragile X syndrome, as well as Huntington’s, Alzheimer’s, and Parkinson’s diseases, among others. Several clinical trials are also underway to assess the therapeutic effects of lithium for treating these disorders. This article reviews the most recent findings regarding the potential targets involved in lithium’s neuroprotective effects, and the implication of these findings for the treatment of a variety of diseases.

Chiu, Chi-Tso; Chuang, De-Maw

2011-01-01

301

Chronic Electrical Stimulation with a Suprachoroidal Retinal Prosthesis: A Preclinical Safety and Efficacy Study  

PubMed Central

Purpose To assess the safety and efficacy of chronic electrical stimulation of the retina with a suprachoroidal visual prosthesis. Methods Seven normally-sighted feline subjects were implanted for 96–143 days with a suprachoroidal electrode array and six were chronically stimulated for 70–105 days at levels that activated the visual cortex. Charge balanced, biphasic, current pulses were delivered to platinum electrodes in a monopolar stimulation mode. Retinal integrity/function and the mechanical stability of the implant were assessed monthly using electroretinography (ERG), optical coherence tomography (OCT) and fundus photography. Electrode impedances were measured weekly and electrically-evoked visual cortex potentials (eEVCPs) were measured monthly to verify that chronic stimuli were suprathreshold. At the end of the chronic stimulation period, thresholds were confirmed with multi-unit recordings from the visual cortex. Randomized, blinded histological assessments were performed by two pathologists to compare the stimulated and non-stimulated retina and adjacent tissue. Results All subjects tolerated the surgical and stimulation procedure with no evidence of discomfort or unexpected adverse outcomes. After an initial post-operative settling period, electrode arrays were mechanically stable. Mean electrode impedances were stable between 11–15 k? during the implantation period. Visually-evoked ERGs & OCT were normal, and mean eEVCP thresholds did not substantially differ over time. In 81 of 84 electrode-adjacent tissue samples examined, there were no discernible histopathological differences between stimulated and unstimulated tissue. In the remaining three tissue samples there were minor focal fibroblastic and acute inflammatory responses. Conclusions Chronic suprathreshold electrical stimulation of the retina using a suprachoroidal electrode array evoked a minimal tissue response and no adverse clinical or histological findings. Moreover, thresholds and electrode impedance remained stable for stimulation durations of up to 15 weeks. This study has demonstrated the safety and efficacy of suprachoroidal stimulation with charge balanced stimulus currents.

Nayagam, David A. X.; Williams, Richard A.; Allen, Penelope J.; Shivdasani, Mohit N.; Luu, Chi D.; Salinas-LaRosa, Cesar M.; Finch, Sue; Ayton, Lauren N.; Saunders, Alexia L.; McPhedran, Michelle; McGowan, Ceara; Villalobos, Joel; Fallon, James B.; Wise, Andrew K.; Yeoh, Jonathan; Xu, Jin; Feng, Helen; Millard, Rodney; McWade, Melanie; Thien, Patrick C.; Williams, Chris E.; Shepherd, Robert K.

2014-01-01

302

Photoacoustic spectroscopy in the monitoring of breast tumor development: a pre-clinical study  

NASA Astrophysics Data System (ADS)

Breast cancer is the most frequently diagnosed cancer type and its detection at an early stage can reduce the mortality rate substantially. With the aim to detect breast cancer early, by studying tumor progression in nude mice, a pulsed laser induced photoacoustic spectroscopy set up has been designed and developed. MCF-7 cells xenografts were developed using six to eight weeks old female nude mice and tumor tissues were extracted on different days (10th, 15th and 20th Day) post injection and the corresponding photoacoustic spectra were recorded at 281nm excitation. A total of 144 time domain spectra were recorded from 36 animals belonging to the three time points (10th, 15th and 20th day post injection) and converted into frequency domains by Fast Fourier Transform (FFT) tools of the MATLAB algorithms and analyzed. The frequency patterns of the tumor masses on 10th, 15th and 20th day of tumor development showed a gradual increase in intensity at certain frequencies, 5.93 x103 Hz, 15.9 x103 Hz, 29.69 x103 Hz and 32.5 x103 Hz in the FFT patterns indicating that these frequencies were more sensitive towards tumor development. Further analysis of the data yielded a clear variation in the spectral parameters with progression of the disease suggesting that the technique may be suitable for early detection of the disease. Thus, we expect that the developed setup may be useful in assessing the different phases of tumor development which may have clinical implications.

Priya, Mallika; Rao, Bola Sadashiva Satish; Ray, Satadru; Mahato, Krishna Kishore

2014-03-01

303

Efficient vitreolysis by combining plasmin and sulfur hexafluoride injection in a preclinical study in rabbit eyes  

PubMed Central

Purpose To investigate the efficacy of plasmin and sulfur hexafluoride (SF6) on the vitreoretinal junction, as well as the long-term safety in the eye and effect on the recipient’s general health after application in the eye. Methods The study design included four groups of rabbits with three animals in each group. Group 1 received an intravitreal injection (IVI) of plasmin and SF6 in the right eye; group 2 received an IVI of plasmin in the right eye; group 3 received an IVI of SF6 in the right eye; and group 4 received an IVI of balanced salt solution in the right eye, which served as a normal control. Long-term safety (up to approximately three months) after plasmin and/or SF6 injection was evaluated morphologically by clinical examination, histology, and immunohistochemistry, and functionally by electroretinograms (ERGs). General health evaluations after intravitreal injection included the assessment of weight gain, food intake, body temperature, and complete blood count analysis. Results Plasmin plus SF6 injection resulted in complete posterior vitreous detachment (PVD), whereas plasmin or SF6 injection alone resulted in only partial PVD. Balanced salt solution did not induce PVD. Eighty days after intravitreal injection, there were no major differences among the eyes of the three groups of animals compared with the normal control animals upon clinical evaluation, or regarding retinal morphology and ERGs. The lenses examined remained clear for up to 80 days following the intravitreal injection of plasmin plus SF6, except one eye in the plasmin-treated group. ERGs decreased transiently one week after intravitreal injection in groups 1 through 3, but animals recovered fully to normal status afterward. General health was not affected after the injection of plasmin plus SF6. Conclusions Efficient vitreoretinal separation could be achieved, and an acceptable long-term safety profile was noted after plasmin plus SF6 injection in the eye. No major ocular toxicity or systemic toxicity was found after the injection of plasmin plus SF6. These results provide good support for the future clinical use of plasmin plus SF6 for treatment of a variety of vitreoretinopathies.

Wu, Wei-Chi; Liu, Chi-Hsien; Chen, Chih-Chun; Wang, Nan-Kai; Chen, Kwan-Jen; Chen, Tun-Lu; Hwang, Yih-Shiou; Li, Lien-Min

2012-01-01

304

Regionally contaminated aquifers--toxicological relevance and remediation options (Bitterfeld case study).  

PubMed

Large-scale contaminated megasites like Bitterfeld in eastern Germany are characterized by a regional contamination of soil, surface water and groundwater as a result of a long and varied history of chemical production. While the contaminants in soils and sediments mostly represent a localized problem, pollutants in groundwater may spread to uncontaminated areas and endanger receptors like surface water and drinking water wells according to the site-specific hydrologic regime. From the toxicological point of view, the contaminants at the Bitterfeld megasite represent a dangerous cocktail of various harmful substances coming from a multitude of sources. Appropriate remediation techniques must be able to remedy the specific problems arising from hot spot areas within the megasite in addition to preventing a further extension of the contaminated zone towards uncontaminated compartments. Therefore, a combination of specifically designed remediation technologies based on the pump and treat-principle with in situ technologies, such as reactive walls and monitored/enhanced natural attenuation, is necessary to efficiently address the miscellaneous challenges at this megasite. In this paper, the currently known contaminant distribution, the associated problems for human health and the environment and possible remediation strategies are presented for the Bitterfeld megasite. PMID:15464625

Heidrich, Susanne; Schirmer, Mario; Weiss, Holger; Wycisk, Peter; Grossmann, Jochen; Kaschl, Arno

2004-12-15

305

Influence of strain and sex on the metabolic profile of rats in repeated dose toxicological studies.  

PubMed

The impact of the strain on the metabolite profile of plasma samples in rats dosed with 2500 ppm 2-methyl-4-chlorophenoxyacetic acid (MCPA acid) or 45 mg/kg bw/day 4-chloro-3-nitroaniline (4C3N) for 4 weeks was evaluated. Four different strains were used: two Wistar strains (Crl:WI(Han), Han:RCC:WIST(SPF)), one Sprague-Dawley (Crl:CD) and one Fisher strain (F-344/Crl). The metabolite profiles in the plasma were measured by LC-MS and GC-MS. The profound changes of the metabolite values induced by the MCPA acid treatment outweighed slight deviations caused by physiological variations between the different rat strains. The metabolome changes of the MCPA acid in all strains could be related to toxicological "mode of action" patterns (peroxisome proliferator, renal organic anionic transporter inhibition) with Crl:WI(Han) rats as reference strain. 4C3N administration led to extravascular hemolytic anemia with a small number of metabolome changes, which were strain dependent. The metabolome pattern associated with "hemolytic anemia" established with the reference strain (Crl:Wi(Han)) was not sufficiently similar in other strains. Thus, comparable metabolome profiles were obtained in different rat strains for a compound inducing profound metabolite changes. For a compound with a weak profile the results were more variable and appeared to be strain dependent. PMID:19683565

Strauss, V; Wiemer, J; Leibold, E; Kamp, H; Walk, T; Mellert, W; Looser, R; Prokoudine, A; Fabian, E; Krennrich, G; Herold, M; van Ravenzwaay, B

2009-12-01

306

Antimicrobial and toxicological studies on an antiseptic based on hexachlorophene and destructive distillate of castor oil.  

PubMed

Bactericidal, bacteriostatic, fungistatic and toxicological evaluaton of an emulsion containing 0.25% hexachlorophene (W/V), 9.5% terpineol (V/V), 1.5% oil of terpentine (V/V), 13% ethanol (V/V), 6% castor oil distillate 1201275 degrees C (V/V) and 6% sodium salt of the residue (W/V) in aqueous medium was performed. The bactericidal concentration for Salmonella typhi was found to be 1:400 which increased to 1:350 in the presence of 5% horse serum. The bacteriostatic concentration of the emulsion varied from organism to organism. A 4% solution of the emulsione was found to be most effective against Microsporum vanbreuseghemii showing an inhibition zone of 7.2 cm and was least effective on Aspergillus niger. 1 to 8% solution of the emulsion given orally or instilled into conjunctival sacs of albino mice indicated lethal and insignificant toxic manifestations respectively but a dose equivalent to 50 mg/Kg given subcutaneously was found to produce a subacute lethal effect in guinea pigs. PMID:549568

Siddiqui, M A; Mahmood, I; Basit, N; Ahmed, S; Bukhari, A Q

1978-01-01

307

Identification of Prenatal Amphetamines Exposure by Maternal Interview and Meconium Toxicology in the Infant Development, Environment and Lifestyle (IDEAL) Study  

PubMed Central

The Infant Development Environment and Lifestyle (IDEAL) study is investigating the effects of prenatal methamphetamine (MAMP) exposure on infant and child development; potential concurrent exposure to cannabis and tobacco also are evaluated. Maternal self-reported drug use and/or meconium toxicology results defined drug exposure status. It is unclear how the frequency, duration and magnitude of maternal MAMP exposure affect qualitative and quantitative meconium results. Materials and Methods Interviews regarding maternal drug use were collected shortly after birth; meconium specimens were screened for amphetamines, cannabis and cotinine by immunoassay and confirmed by gas chromatography mass spectrometry (GCMS). Results The majority of MAMP- and cannabis-exposed infants were identified by maternal interview alone. Meconium tests were more likely to be positive if the mother reported MAMP and cannabis use, particularly in the third trimester. Less than half of immunoassay-positive amphetamines (31.0%) and cannabis (17.9%) meconium results were confirmed by GCMS. Tobacco exposure was equally detected by immunoassay cotinine screen and maternal report. Meconium concentrations did not correlate with maternal self-report status or trimester of use, frequency or route of MAMP use. Discussion Maternal self-report was more sensitive than meconium testing for identifying MAMP and cannabis-exposed neonates; however, the timing of drug exposure may influence meconium toxicology results. Most women ceased MAMP and cannabis use before the third trimester. In the first trimester, meconium has not yet formed, and based on our recent results for opiates and cocaine, drug use in the second trimester appears to be poorly reflected in meconium. Conclusion Low confirmation rates in meconium reinforce the need for confirmatory testing following positive screening results and additional research to identify alternative biomarkers.

Gray, Teresa R.; LaGasse, Linda L.; Smith, Lynne M.; Derauf, Chris; Grant, Penny; Shah, Rizwan; Arria, Amelia M.; Della Grotta, Sheri A.; Strauss, Arthur; Haning, William F.; Lester, Barry M.; Huestis, Marilyn A.

2009-01-01

308

Identification of prenatal amphetamines exposure by maternal interview and meconium toxicology in the Infant Development, Environment and Lifestyle (IDEAL) study.  

PubMed

The Infant Development Environment and Lifestyle study is investigating the effects of prenatal methamphetamine (MAMP) exposure on infant and child development; potential concurrent exposure to cannabis and tobacco also are evaluated. Maternal self-reported drug use and/or meconium toxicology results defined drug exposure status. It is unclear how the frequency, duration, and magnitude of maternal MAMP exposure affect qualitative and quantitative meconium results. Interviews regarding maternal drug use were collected shortly after birth; meconium specimens were screened for amphetamines, cannabis, and cotinine by immunoassay and confirmed by gas chromatography mass spectrometry. The majority of MAMP- and cannabis-exposed infants were identified by maternal interview alone. Meconium tests were more likely to be positive if the mother reported MAMP and cannabis use, particularly in the third trimester. Less than half of immunoassay-positive amphetamines (31.0%) and cannabis (17.9%) meconium results were confirmed by gas chromatography mass spectrometry. Tobacco exposure was equally detected by immunoassay cotinine screening and maternal report. Meconium concentrations did not correlate with maternal self-report status or trimester of use or frequency or route of MAMP use. Maternal self-report was more sensitive than meconium testing for identifying MAMP and cannabis-exposed neonates; however, the timing of drug exposure may influence meconium toxicology results. Most women stopped MAMP and cannabis use before the third trimester. In the first trimester, meconium has not yet formed, and based on our recent results for opiates and cocaine, drug use in the second trimester appears to be poorly reflected in meconium. Low confirmation rates in meconium reinforce the need for confirmatory testing following positive screening results and additional research to identify alternative biomarkers. PMID:19935364

Gray, Teresa R; LaGasse, Linda L; Smith, Lynne M; Derauf, Chris; Grant, Penny; Shah, Rizwan; Arria, Amelia M; Della Grotta, Sheri A; Strauss, Arthur; Haning, William F; Lester, Barry M; Huestis, Marilyn A

2009-12-01

309

Toxicological properties of metaflumizone.  

PubMed

Metaflumizone is a new insecticide developed for crop protection and urban pest control by BASF. Its mammalian toxicological profile was assessed by conducting multiple toxicity studies in the rat, mouse, and dog, covering all relevant endpoints. Metaflumizone is characterized by very low acute toxicity, is not irritating to the eye or the skin and does not possess a potential to induce skin sensitization. The substance also shows relatively low toxicity following subchronic oral or dermal exposure to mammals. In addition, metaflumizone demonstrates low toxicological potential following chronic oral exposure to rats, mice, and dogs. Overall, the lowest no observed adverse effect level (NOAEL) is 12mg/(kgday) from the 1-year chronic dog study. In a battery of in vitro and in vivo mutagenicity assays, the weight-of-the-evidence indicates a lack of potential genotoxicity for metaflumizone. Furthermore, the compound demonstrated a lack of potential oncogenicity in long-term toxicity studies in rats and mice. Results from the rat multi-generation reproductive toxicity study as well as the rat and rabbit developmental toxicity studies indicate that metaflumizone is not selectively toxic to the offspring or fetus, as compared to the parents. Also, metaflumizone is not teratogenic in the rat or rabbit. Lastly, no neurotoxicity could be detected in acute and subchronic neurotoxicity studies in rats. PMID:17933467

Hempel, K; Hess, F G; Bögi, C; Fabian, E; Hellwig, J; Fegert, I

2007-12-15

310

Toxicology and Carcinogenesis Studies of Hexachloroethane (CAS No. 67-72-1) in F344/N Rats (Gavage Studies).  

PubMed

Hexachloroethane is used in organic synthesis as a retarding agent in fermentation, as a camphor substitute in nitrocellulose, in pyrotechnics and smoke devices, in explosives, and as a solvent. In previous long-term gavage studies with B6C3F1 mice and Osbourne-Mendel rats (78 weeks of exposure followed by 12-34 weeks of observation), hexachloroethane caused increased incidences of hepatocellular carcinomas in mice. However, survival of low and high dose rats was reduced compared with that of vehicle controls, and the effects on rats were inconclusive. Therefore, additional toxicology and carcinogenesis studies were conducted in F344/N rats by administering hexachloroethane (approximately 99% pure) in corn oil by gavage to groups of males and females for 16 days, 13 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium and in Chinese hamster ovary (CHO) cells. Urinalysis was performed in conjunction with the 13-week studies. Sixteen-Day Studies: In the 16-day studies (dose range, 187-3,000 mg/kg), all rats that received 1,500 or 3,000 mg/kg and 1/5 males and 2/5 females that received 750 mg/kg died before the end of the studies. Final mean body weights of rats that received 750 mg/kg were 25% lower than that of vehicle controls for males and 37% lower for females. Compound-related clinical signs seen at 750 mg/kg or more included dyspnea, ataxia, prostration, and excessive lacrimation. Other compound-related effects included hyaline droplet formation in the tubular epithelial cells in all dosed males and tubular cell regeneration and granular casts in the tubules at the corticomedullary junction in the kidney in males receiving 187 and 375 mg/kg. Thirteen-Week Studies: In the 13-week studies (dose range, 47-750 mg/kg), 5/10 male rats and 2/10 female rats that received 750 mg/kg died before the end of the studies. The final mean body weight of male rats that received 750 mg/kg was 19% lower than that of vehicle controls. Compound-related clinical signs for both sexes included hyperactivity at doses of 94 mg/kg or higher and convulsions at doses of 375 or 750 mg/kg. The relative weights of liver, heart, and kidney were increased for exposed males and females. Kidney lesions were seen in all dosed male groups, and the severity increased with dose. Papillary necrosis and tubular cell necrosis and degeneration in the kidney and hemorrhagic necrosis in the urinary bladder were observed in the five male rats that received 750 mg/kg and died before the end of the studies; at all lower doses, hyaline droplets, tubular regeneration, and granular casts were present in the kidney. No chemical-related kidney lesions were observed in females. Foci of hepatocellular necrosis were observed in several male and female rats at doses of 188 mg/kg or higher. Dose selection for the 2-year studies was based primarily on the lesions of the kidney in males and of the liver in females. Studies were conducted by administering hexachloroethane in corn oil by gavage at 0, 10, or 20 mg/kg body weight, 5 days per week, to groups of 50 male rats. Groups of 50 female rats were administered 0, 80, or 160 mg/kg on the same schedule. Body Weight and Survival in the Two-Year Studies: Mean body weights of high dose rats were slightly (5%-9%) lower than those of vehicle controls toward the end of the studies. No significant differences in survival were observed between any groups of rats (male: vehicle control, 31/50; 10 mg/kg, 29/50; 20 mg/kg, 26/50; female: vehicle control, 32/50; 80 mg/kg, 27/50; 160 mg/kg, 32/50). Nonneoplastic and Neoplastic Effects in the Two-Year Studies: Incidences of kidney mineralization (vehicle control, 2/50; low dose, 15/50; high dose, 32/50) and hyperplasia of the pelvic transitional epithelium (0/50; 7/50; 7/50) were increased in dosed male rats. Renal tubule hyperplasia was observed at an increased incidence in high dose male rats (2/50; 4/50; 11/50). These lesions have been described as characteristic of the hyaline droplet nephropathy that is associated with an accumulation of liver-generatet

1989-08-01

311

No Association of nineteen COX-2 gene variants to preclinical markers of atherosclerosis The Cardiovascular Risk in Young Finns Study  

PubMed Central

Backgroud The role of cyclooxygenase-2 (COX-2) single nucleotide polymorphisms has mostly been studied in relation to advanced atherosclerosis, but little is known how they contribute to preclinical disease. In the present study we analyzed whether COX-2 gene variants associate independently with the early subclinical markers of atherosclerosis, carotid intima-media thickness and carotid artery distensibility in a population of young healthy Caucasian adults. Methods SNPs for association analysis were collected from the COX-2 gene and 5?kb up- and downstream of it. There were 19 SNPs available for analysis, four genotyped and fifteen imputed. Genotype data was available for 2442 individuals participating in the Cardiovascular Risk in Young Finns Study. Genotype imputation was performed using MACH 1.0 and HapMap II CEU (release 22) samples as reference. Association analysis was performed using linear regression with an additive model. PLINK was used for true genotyped SNPs and ProbABEL for imputed genotype dosages. False discovery rate was used to take into account multiple testing bias. Results Two of the COX-2 variants (rs689470, rs689462) associated with distensibility (p?=?0.005) under the linear regression additive model. After adjustment with gender, age, body mass index and smoking status, association between these SNPs and distensibility remained significant (p?=?0.031). Subjects carrying the minor alleles had higher value of carotid artery distensibility compared to the major allele homozygotes. However, after correcting p-values for multiple testing bias using false discovery rate, association was lost. Another COX-2 variant rs4648261 associated with mean carotid intima-media thickness (p?=?0.046) and maximal carotid intima-media thickness (p?=?0.048) in the linear regression model. Subjects carrying the minor allele of rs4648261 had lower values of mean and maximal carotid intima-media thickness compared to subjects homozygote for major allele. After adjustments the associations were lost with both mean and maximal carotid intima-media thickness. Thus, no statistically significant associations of the studied COX-2 variants with carotid artery distensibility or carotid intima-media thickness were found. Conclusions Our results suggest that in a Finnish population, there are no significant associations between COX-2 variants and early atherosclerotic changes in young adulthood.

2012-01-01

312

Reproductive Toxicology Testing with EDCS  

EPA Science Inventory

An introduction to reproductive toxicology: the basic approaches to testing chemicals for adverse effects using multigenerational studies with rats and how the regulatory agencies used the data in risk assessments. Case studies were presented of how endocrine or genomic data were...

313

Toxicology and Carcinogenesis Studies of 8-Methoxypsoralen (CAS No. 298-81-7) in F344/N Rats (Gavage Studies).  

PubMed

Oral administration of 8-methoxypsoralen followed by exposure to longwave ultraviolet light (primarily ultraviolet A, 320-400 nm) is used in the treatment of vitiligo and psoriasis. 8-Methoxypsoralen also occurs naturally in a variety of vegetables. Toxicology and carcinogenesis studies of 8-methoxypsoralen without ultraviolet A were conducted by administering USP-grade 8-methoxypsoralen (99% pure) in corn oil by gavage to groups of F344/N rats once or for 16 days, 13 weeks, or 2 years. In vitro genetic toxicology tests were performed with bacteria and mammalian cells. Single-Administration, Sixteen-Day, and Thirteen-Week Studies: In the single-administration studies, the chemical was administered at doses of 0 and 63-1,000 mg/kg. Four of five male rats and 5/5 female rats that received 1,000 mg/kg 8-methoxypsoralen died within 2 days. In the 16-day studies, the chemical was administered at doses of 0 and 50-800 mg/kg. All rats receiving 800 mg/kg died within 5 days, and one male and one female at 400 mg/kg and one female at 200 mg/kg also died before the end of the studies. The final mean body weights of animals at 200 or 400 mg/kg were 14% or 30% lower than those of vehicle controls. No compound-related effects were observed at necropsy. In the 13-week studies, the chemical was administered at doses of 0 and 25-400 mg/kg. Six of 10 male rats and 8/10 female rats that received 400 mg/kg died before the end of the studies. The final mean body weight of male rats that received 100, 200, or 400 mg/kg was 12%, 22%, or 45% lower than that of vehicle controls. The final mean body weight of female rats that received 200 or 400 mg/kg was 15% or 35% lower than that of vehicle controls. The liver weight to body weight ratios for all dosed groups of rats except the lowest (25 mg/kg) were greater than those for vehicle controls. Compound-related effects included fatty change in the liver in males and females and atrophy of the testis, seminal vesicles, and prostate. Based on these results, 2-year studies were conducted by administering 0, 37.5 or 75 mg/kg 8-methoxypsoralen in corn oil by gavage, 5 days per week for 103 weeks, to groups of 50 F344/N rats of each sex. Body Weight and Survival in the Two-Year Studies: The mean body weights of dosed male rats were generally 3%-14% lower than those of vehicle controls, and the mean body weights of high dose female rats were 5%-17% lower. The survival of both the low and the high dose groups of male rats was lower than that of the vehicle controls (male: vehicle control, 30/50; low dose, 16/50; high dose, 16/50; female: 39/50; 33/50; 36/50), likely because of kidney toxicity and neoplasia. Nonneoplastic and Neoplastic Effects in the Two-Year Studies: Mineralization of the renal papilla was observed in high dose male rats (vehicle control, 0/50; low dose, 0/50; high dose, 31/49). The severity of nephropathy was increased in dosed male rats. Focal hyperplasia of renal tubular cells was observed in dosed male rats (0/50; 8/50; 8/49). The incidences of tubular cell adenomas (1/50; 11/50; 8/49), adenocarcinomas (0/50; 1/50; 3/49), and adenomas or adenocarcinomas (combined) (1/50; 12/50; 11/49) were increased in dosed male rats. Hyperplasia of the parathyroid glands (2/49; 22/47; 18/48) and fibrous osteodystrophy (2/50; 10/50; 12/49) in male rats were secondary to chronic nephropathy. The incidences of carcinomas or squamous cell carcinomas (combined) of the Zymbal gland were increased in dosed male rats (1/50; 7/50; 4/49). The mean historical incidence for carcinomas or squamous cell carcinomas (combined) in corn oil vehicle control male F344/N rats is 0.8% (16/1,949); the highest incidence in any one group is 4% (2/49). Fibromas of the subcutaneous tissue in male rats occurred with a positive trend (1/50; 5/50; 7/49). An additional high dose male had a sarcoma. The mean historical incidence of fibromas or fibrosarcomas (combined) of subcutaneous tissue in corn oil vehicle control male F344/N rats is 9% (171/1,949). Alveolar/bronchiolar adenomas occurred with a positive trend in male rats (4t

1989-07-01

314

Nanotechnology: toxicologic pathology.  

PubMed

Nanotechnology involves technology, science, and engineering in dimensions less than 100 nm. A virtually infinite number of potential nanoscale products can be produced from many different molecules and their combinations. The exponentially increasing number of nanoscale products will solve critical needs in engineering, science, and medicine. However, the virtually infinite number of potential nanotechnology products is a challenge for toxicologic pathologists. Because of their size, nanoparticulates can have therapeutic and toxic effects distinct from micron-sized particulates of the same composition. In the nanoscale, distinct intercellular and intracellular translocation pathways may provide a different distribution than that obtained by micron-sized particulates. Nanoparticulates interact with subcellular structures including microtubules, actin filaments, centrosomes, and chromatin; interactions that may be facilitated in the nanoscale. Features that distinguish nanoparticulates from fine particulates include increased surface area per unit mass and quantum effects. In addition, some nanotechnology products, including the fullerenes, have a novel and reactive surface. Augmented microscopic procedures including enhanced dark-field imaging, immunofluorescence, field-emission scanning electron microscopy, transmission electron microscopy, and confocal microscopy are useful when evaluating nanoparticulate toxicologic pathology. Thus, the pathology assessment is facilitated by understanding the unique features at the nanoscale and the tools that can assist in evaluating nanotoxicology studies. PMID:23389777

Hubbs, Ann F; Sargent, Linda M; Porter, Dale W; Sager, Tina M; Chen, Bean T; Frazer, David G; Castranova, Vincent; Sriram, Krishnan; Nurkiewicz, Timothy R; Reynolds, Steven H; Battelli, Lori A; Schwegler-Berry, Diane; McKinney, Walter; Fluharty, Kara L; Mercer, Robert R

2013-02-01

315

Toxicological assessment of inhaled nanoparticles: role of in vivo, ex vivo, in vitro, and in silico studies.  

PubMed

The alveolar epithelium of the lung is by far the most permeable epithelial barrier of the human body. The risk for adverse effects by inhaled nanoparticles (NPs) depends on their hazard (negative action on cells and organism) and on exposure (concentration in the inhaled air and pattern of deposition in the lung). With the development of advanced in vitro models, not only in vivo, but also cellular studies can be used for toxicological testing. Advanced in vitro studies use combinations of cells cultured in the air-liquid interface. These cultures are useful for particle uptake and mechanistic studies. Whole-body, nose-only, and lung-only exposures of animals could help to determine retention of NPs in the body. Both approaches also have their limitations; cellular studies cannot mimic the entire organism and data obtained by inhalation exposure of rodents have limitations due to differences in the respiratory system from that of humans. Simulation programs for lung deposition in humans could help to determine the relevance of the biological findings. Combination of biological data generated in different biological models and in silico modeling appears suitable for a realistic estimation of potential risks by inhalation exposure to NPs. PMID:24646916

Fröhlich, Eleonore; Salar-Behzadi, Sharareh

2014-01-01

316

Toxicological Assessment of Inhaled Nanoparticles: Role of in Vivo, ex Vivo, in Vitro, and in Silico Studies  

PubMed Central

The alveolar epithelium of the lung is by far the most permeable epithelial barrier of the human body. The risk for adverse effects by inhaled nanoparticles (NPs) depends on their hazard (negative action on cells and organism) and on exposure (concentration in the inhaled air and pattern of deposition in the lung). With the development of advanced in vitro models, not only in vivo, but also cellular studies can be used for toxicological testing. Advanced in vitro studies use combinations of cells cultured in the air-liquid interface. These cultures are useful for particle uptake and mechanistic studies. Whole-body, nose-only, and lung-only exposures of animals could help to determine retention of NPs in the body. Both approaches also have their limitations; cellular studies cannot mimic the entire organism and data obtained by inhalation exposure of rodents have limitations due to differences in the respiratory system from that of humans. Simulation programs for lung deposition in humans could help to determine the relevance of the biological findings. Combination of biological data generated in different biological models and in silico modeling appears suitable for a realistic estimation of potential risks by inhalation exposure to NPs.

Frohlich, Eleonore; Salar-Behzadi, Sharareh

2014-01-01

317

Glucocorticoid-Treated Mice Are an Inappropriate Positive Control for Long-Term Preclinical Studies in the mdx Mouse  

PubMed Central

Background Dmdmdx (mdx) mice are used as a genetic and biochemical model of dystrophin deficiency. The long-term consequences of glucocorticoid (GC) treatment on dystrophin-deficient skeletal and heart muscle are not yet known. Here we used systematic phenotyping to assess the long-term consequences of GC treatment in mdx mice. Our investigation addressed not only the effects of GC on the disease phenotype but also the question of whether GCs can be used as a positive control for preclinical drug evaluations. Methods and Findings We performed nine pre-clinical efficacy trials (treated N?=?129, untreated N?=?106) of different durations in 9-to-50-week-old dystrophic mdx mice over a 3-year time period using standardized methods. In all these trials, we used either 1 mg/kg body weight of prednisone or 5 mg/kg body weight of prednisolone as positive controls to compare the efficacy of various test drugs. Data from untreated controls and GC-treated mice in the various trials have been pooled and analyzed to assess the effects of GCs on dystrophin-deficient skeletal and cardiac muscles of mdx mice. Our results indicate that continuous GC treatment results in early (e.g., at 50 days) improvements in normalized parameters such as grip strength, motor coordination and maximal in vitro force contractions on isolated EDL muscle, but these initial benefits are followed by a progressive loss of muscle strength after 100 days. We also found a significant increase in heart fibrosis that is reflected in a significant deterioration in cardiac systolic function after 100 days of treatment. Conclusion Continuous administration of prednisone to mdx mice initially improves skeletal muscle strength, but further therapy result in deterioration of muscle strength and cardiac function associated with enhanced cardiac fibrosis. These results suggest that GCs may not serve as an appropriate positive control for long-term mdx mouse preclinical trials.

Gordish-Dressman, Heather; Spurney, Christopher F.; Iantorno, Micaela; Hoffman, Eric P.; Nagaraju, Kanneboyina

2012-01-01

318

Toxicological assessment of ?-(1-->6)-glucan (lasiodiplodan) in mice during a 28-day feeding study by gavage.  

PubMed

Studies evaluating the toxicity caused by fungal exopolysaccharides of the ?-(1-->6)-D-glucan type are rare. In this study, the toxicological effects of sub-chronic treatments with lasiodiplodan (?-(1-->6)-D-glucan from Lasiodiplodia theobromae MMPI) were evaluated in mice through the assessment of biochemical, hematological, and histopathological alterations. Thirty-two mice (16 male, 16 female) were used in this study divided in two groups; one group received lasiodiplodan (50 mg/kg body weight) daily for 28 days via gavage, and another (control group) received saline during the same period. Blood samples were collected via cardiac puncture for hematological and biochemical analyses. Liver, heart, kidney, and spleen were collected for histopathological analysis. Statistical analysis was performed through one-way analysis of variance and only p < 0.05 F-values were presented. Significant reduction in blood glucose in the male group (35%; p < 0.01), transaminases activity in both sexes (AST and ALT; ~35%; p < 0.05), and urea (20%; p < 0.01) in the female group was observed with the lasiodiplodan treatment. The results showed that sub-chronic treatments with lasiodiplodan did not generate hematological and histopathological alterations leading to signs of toxicity in healthy mice, independent of gender. PMID:23208465

Túrmina, Janaína A; Carraro, Emerson; Alves da Cunha, Mário A; Dekker, Robert F H; Barbosa, Aneli M; Dos Santos, Fábio Seidel; Silva, Luiz A; Malfatti, Carlos R M

2012-01-01

319

Preclinical development of keliximab, a Primatized anti-CD4 monoclonal antibody, in human CD4 transgenic mice: characterization of the model and safety studies.  

PubMed

The preclinical safety assessment of biopharmaceuticals necessitates that studies be conducted in species in which the products are pharmacologically active. Monoclonal antibodies are a promising class of biopharmaceuticals for many disease indications; however, by design, these agents tend to have limited species cross-reactivity and tend to only be active in primates. Keliximab is a human-cynomolgus monkey chimeric (Primatized) monoclonal antibody with specificity for human and chimpanzee CD4. In order to conduct a comprehensive preclinical safety assessment of this antibody to support chronic treatment of rheumatoid arthritis in patients, a human CD4 transgenic mouse was used for chronic and reproductive toxicity studies and for genotoxic studies. In addition, immunotoxicity studies were conducted in these mice with Candida albicans, Pneumocystis carinii and B16 melanoma cells to assess the effects of keliximab on host resistance to infection and immunosurveillance to neoplasia. The results of these studies found keliximab to be well tolerated with the only effects observed being related to its pharmacologic activity on CD4+ T lymphocytes. The use of transgenic mice expressing human proteins provides a useful alternative to studies in chimpanzees with biopharmaceutical agents having limited species cross-reactivity. PMID:10918514

Bugelski, P J; Herzyk, D J; Rehm, S; Harmsen, A G; Gore, E V; Williams, D M; Maleeff, B E; Badger, A M; Truneh, A; O'Brien, S R; Macia, R A; Wier, P J; Morgan, D G; Hart, T K

2000-04-01

320

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

321

Studies on the metabolism and toxicological detection of the new designer drug 4?-methyl-?-pyrrolidinopropiophenone in urine using gas chromatography–mass spectrometry  

Microsoft Academic Search

4?-Methyl-?-pyrrolidinopropiophenone (MPPP) is a new designer drug which has appeared on the illicit drug market. The aim of our study was to identify the MPPP metabolites and to develop a toxicological detection procedure in urine using solid-phase extraction, ethylation and GC–MS. In urine samples of rats treated with MPPP, MPPP was found to be completely metabolized by oxidative desamination, hydroxylation

Dietmar Springer; Frank T. Peters; Giselher Fritschi; Hans H. Maurer

2002-01-01

322

Metabolism and toxicological detection of the new designer drug 3?,4?-methylenedioxy-?-pyrrolidinopropiophenone studied in urine using gas chromatography–mass spectrometry  

Microsoft Academic Search

R,S-3?,4?-Methylenedioxy-?-pyrrolidinopropiophenone (MDPPP) is a new designer drug with assumed amphetamine-like effects, which has appeared on the illicit drug market. The aim of this study was to identify the MDPPP metabolites using solid-phase extraction, ethylation or acetylation as well as to develop a toxicological detection procedure in urine using solid-phase extraction, trimethylsilylation and GC–MS. Analysis of urine samples of rats treated

Dietmar Springer; Giselher Fritschi; Hans H. Maurer

2003-01-01

323

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...

324

Impaired Gamete Function: Implications for Reproductive Toxicology.  

National Technical Information Service (NTIS)

The invited symposium chapter reviews methods for evaluating sperm function in laboratory rodents and humans, and presents strategies for incorporating both in vivo and in vitro fertilization assessments into reproductive toxicology studies. The EPA Progr...

S. D. Perreault

1989-01-01

325

IMPAIRED GAMETE FUNCTION: IMPLICATIONS FOR REPRODUCTIVE TOXICOLOGY  

EPA Science Inventory

The invited symposium chapter reviews methods for evaluating sperm function in laboratory rodents and humans, and presents strategies for incorporating both in vivo and in vitro fertilization assessments into reproductive toxicology studies. The EPA Program Offices may encounter ...

326

An overview of the toxicology of HFA-134a (1,1,1,2-tetrafluoroethane).  

PubMed

1. This paper reviews the results of preclinical toxicology studies on HFA-134a carried out by Glaxo Research and Development Ltd. 2. A comprehensive range of studies was conducted in animal models suitable for the type of investigation. 3. The inhalation route of administration was used in all in vivo studies (with the exception of local tolerance and sensitisation studies) as patients will be exposed only to vapour during actuation of metered-dose inhalers. Cell cultures used for in vitro studies were also exposed to the vapour. 4. There was no mortality of rodents or dogs at extremely high vapour concentrations (81%v/v) 5. HFA-134a was considered not to be toxic or oncogenic and to provide a safe alternative to chlorofluorocarbons for use in pharmaceutical metered-dose inhalers. PMID:8579881

Alexander, D J; Libretto, S E

1995-09-01

327

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

328

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

329

The application of ICH S6 to the preclinical safety evaluation of plasma derivative therapeutic products.  

PubMed

The ICH S6 guidance was developed to describe a rational science-based flexible approach to the preclinical evaluation for biotechnology-derived pharmaceutical products. It also suggested that some of the principles described may be suitable for plasma-derived therapeutics. Some of the specific concerns unique to protein-based therapeutics include complexity in structure and potential immunogenicity. S6 has been interpreted by some industry and regulatory authorities, often due to lack of experience with these types of products, as encouraging a broader or more conventional toxicology program similar to that normally conducted for small molecules. The guidance does encourage important and necessary preclinical evaluations but also recognizes the limitations of studies in non-relevant animal species because they are without pharmacological interaction with the biologic. In addition, studies of human proteins are often limited in useful chronic, reproductive and carcinogenic toxicity evaluations by the immunological response in animals. Thus the safety evaluation of biopharmaceuticals and plasma derivatives in animals has limitations that cannot be adequately addressed by the use of testing paradigms used for small molecule pharmaceuticals. S6 focuses evaluations on well-designed studies in relevant species for reasonable time periods to make the best use of available resources and enable clinical trials. PMID:20359910

Lewis, Richard M; Cavagnaro, Joy

2010-07-01

330

GENOMIC ADAPTATION OF THE EMBRYONIC STEM CELL TEST (EST) FOR A TOXICOLOGICAL STUDY OF DRINKING WATER DISINFECTION BY-PRODUCTS  

EPA Science Inventory

Among the many promised and potential applications of embryonic stem cells, in vitro toxicology is one area in which ES cells have already proven their utility. In 2003, the Embryonic Stem Cell Test (EST) protocol was validated in Europe as an in vitro alternative to live animal...

331

Meta-Analysis of Pre-Clinical Studies of Early Decompression in Acute Spinal Cord Injury: A Battle of Time and Pressure  

PubMed Central

Background The use of early decompression in the management of acute spinal cord injury (SCI) remains contentious despite many pre-clinical studies demonstrating benefits and a small number of supportive clinical studies. Although the pre-clinical literature favours the concept of early decompression, translation is hindered by uncertainties regarding overall treatment efficacy and timing of decompression. Methods We performed meta-analysis to examine the pre-clinical literature on acute decompression of the injured spinal cord. Three databases were utilised; PubMed, ISI Web of Science and Embase. Our inclusion criteria consisted of (i) the reporting of efficacy of decompression at various time intervals (ii) number of animals and (iii) the mean outcome and variance in each group. Random effects meta-analysis was used and the impact of study design characteristics assessed with meta-regression. Results Overall, decompression improved behavioural outcome by 35.1% (95%CI 27.4-42.8; I2=94%, p<0.001). Measures to minimise bias were not routinely reported with blinding associated with a smaller but still significant benefit. Publication bias likely also contributed to an overestimation of efficacy. Meta-regression demonstrated a number of factors affecting outcome, notably compressive pressure and duration (adjusted r2=0.204, p<0.002), with increased pressure and longer durations of compression associated with smaller treatment effects. Plotting the compressive pressure against the duration of compression resulting in paraplegia in individual studies revealed a power law relationship; high compressive forces quickly resulted in paraplegia, while low compressive forces accompanying canal narrowing resulted in paresis over many hours. Conclusion These data suggest early decompression improves neurobehavioural deficits in animal models of SCI. Although much of the literature had limited internal validity, benefit was maintained across high quality studies. The close relationship of compressive pressure to the rate of development of severe neurological injury suggests that pressure local to the site of injury might be a useful parameter determining the urgency of decompression.

Skeers, Peta; Battistuzzo, Camila R.; Macleod, Malcolm R.; Howells, David W.; Sena, Emily S.

2013-01-01

332

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...

333

A pharmacokinetic study of ethyl glucuronide in blood and urine: Applications to forensic toxicology  

Microsoft Academic Search

This pharmacokinetic study investigated the kinetics of ethanol and its metabolite ethyl glucuronide (EtG) in blood and urine during the whole time course of absorption and elimination. There are few previous studies on the kinetics of EtG in blood, and we wanted to evaluate whether such knowledge could yield valuable information regarding the time of ethanol ingestion in forensic cases,

Gudrun Høiseth; Jean Paul Bernard; Ritva Karinen; Lene Johnsen; Anders Helander; Asbjørg S. Christophersen; Jørg Mørland

2007-01-01

334

Chemical and Mechanistic Toxicology Evaluation of Exon Skipping Phosphorodiamidate Morpholino Oligomers in mdx Mice  

Microsoft Academic Search

AVI-4658 is a phosphorodiamidate morpholino oligomer (PMO) designed to induce skipping of dystrophin exon 51 and restore its expression in patients with Duchenne muscular dystrophy (DMD). Preclinically, restoration of dystrophin in the dystrophic mdx mouse model requires skipping of exon 23, achieved with the mouse-specific PMO, AVI-4225. Herein, we report the potential toxicological consequences of exon skipping and dystrophin restoration

Peter Sazani; Kirk P. Van Ness; Doreen L. Weller; Duane Poage; Keith Nelson; Stephen B. Shrewsbury

2011-01-01

335

Chemical and Toxicological Studies of Coal Gasification Wastewater Circulated Through a Cooling Tower.  

National Technical Information Service (NTIS)

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 stu...

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

1984-01-01

336

Toxicological evaluation of peroxy sulfonated oleic acid (PSOA) in subacute and developmental toxicity studies.  

PubMed

Peroxy sulfonated oleic acid (PSOA) is a new coupler used in sanitizing solutions primarily for the food and beverage industry. The toxicity of PSOA was evaluated in a 28-day repeat dose study according to OECD 407 guidelines with a 14-day recovery period and a developmental toxicity study according to OECD 414 guidelines. In both studies, PSOA was administered once daily via gavage at 0, 5, 15 and 50 mg/kg/day to Sprague-Dawley rats. Due to its corrosive properties, the highest test concentration was restricted to 0.5%. No findings related to PSOA administration were observed for the 28-day repeat-dose study and the NOEL is 50 mg/kg/day. Additionally, no impairment of the mucous membranes of the gastrointestinal tract was observed up to 0.5%, which is considered the NOEC in terms of local toxicity. For the developmental study, an embryo-fetal NOEL of 50 mg/kg/day was identified and the maternal NOEL is considered to be 15 mg/kg/day, based on slight reductions in maternal body weight and food consumption, as well as a modest increase in the incidence of clinical observations at the high dose. These findings demonstrate that PSOA appears to have minimal potential to induce toxicity associated with repeat-dose or developmental exposures. PMID:24007740

Pechacek, Nathan; Laidlaw, Karen; Clubb, Stephanie; Aulmann, Walter; Osorio, Magdalena; Caudill, Jeff

2013-12-01

337

Toxicology and Carcinogenesis Studies of 'dl'-Amphetamine Sulfate (Cas No. 60-13-9) in F344/N Rats and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies were conducted by feeding diets containing 0, 20, or 100 ppm dl-amphetamine sulfate to groups of 50 rats and 50 mice of each sex for 103 weeks. Under the conditions of these 2-year feed studies, there was no evidence ...

1991-01-01

338

Toxicology and Carcinogenesis Studies of 2-Amino-5-Nitrophenol (CAS No. 121-88-0) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies were conducted by administering 2-amino-5-nitrophenol (98% pure) by gavage in corn oil 5 days per week to groups of F344/N rats and B6C3F1 mice of each sex in 16-day, 13-week and 2-year studies. In the 2-year...

R. D. Irwin

1988-01-01

339

Toxicity profile of lisdexamfetamine dimesylate in three independent rat toxicology studies.  

PubMed

Lisdexamfetamine dimesylate (LDX) is a d-amphetamine prodrug developed for the treatment of attention-deficit/hyperactivity disorder. The toxicity profile of orally administered LDX has been evaluated in rats. In an acute study, LDX doses of 60 mg/kg and higher caused increased motor activity. At 1000 mg/kg, one rat died and another was euthanized. In a 7-day repeat-dose study, all rats dosed with LDX (14 per dose group for each sex) showed increased activity; 10 male rats and 11 female rats at 300 mg/kg/day and 3 female rats at 100 mg/kg/day were euthanized because of self-mutilation and 1 male rat at 300 mg/kg/day was found dead. In a 28-day study, only rats at 80 mg/kg showed signs of self-mutilation and thin body condition. In both the 7- and 28-day studies, LDX caused significant changes in some blood chemistry parameters (e.g. blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase) and organ weights (e.g. particularly heart, liver, brain, and spleen). Overall, no apparent treatment-related histopathologic changes were observed. Toxicokinetic assessments indicated that as the dose of LDX was increased, rats were exposed to increasing levels of LDX and d-amphetamine. The extent of exposure to LDX and d-amphetamine increased after repeated-dose in the 28-day study. The findings of the repeat-dose studies indicate that the toxicity profile in rats administered LDX orally is comparable to that for d-amphetamine; however, the apparent lethal dose of LDX in rats is more than five times higher than the LD(50) of orally administered d-amphetamine, supporting a putative protective effect of conjugating amphetamine with lysine. PMID:17845504

Krishnan, Suma; Montcrief, Scott

2007-10-01

340

Toward a Checklist for Exchange and Interpretation of Data froma Toxicology Study  

EPA Science Inventory

With the advent of toxicogenomics came the need to share data across interdisciplinary teams and to deposit data associated with publications into public data repositories. Within a single institution, many variables associated with a study are standardized, for instance diet, an...

341

HEART RATE VARIABILITY IN RODENTS ? USES AND CAVEATS IN TOXICOLOGICAL STUDIES  

EPA Science Inventory

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 ...

342

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

343

The rodent estrous cycle: Characterization of vaginal cytology and its utility in toxicological studies  

EPA Science Inventory

An evaluation of the estrous cycle in laboratory rodents can be a useful measure of the integrity of the hypothalamic-pituitary-ovarian reproductive axis. It can also serve as a way of insuring that animals exhibiting abnormal cycling patterns are disincluded from a study prior t...

344

STUDY OF THE CHEMICAL AND BEHAVIORAL TOXICOLOGY OF SUBSTITUTE CHEMICALS IN MICROTINE RODENTS  

EPA Science Inventory

Acute oral LD50 and 30-day dietary subacute LC50 studies of 10 selected pesticides were evaluated in microtine rodents. As a means to developing new animal model systems, four species of microtine rodents including Microtus ochrogaster (MO), Microtus canicaudus (MC), Microtus pen...

345

Toxicological and cytogenetic assessment of a Salacia oblonga extract in a rat subchronic study  

Microsoft Academic Search

Salacia oblonga holds potential as a natural method to mitigate the blood glucose response for people with diabetes by inhibiting the activity of intestinal ?-glucosidases. As part of a safety evaluation of novel ingredients for use in blood glucose control, the toxicity of a S. oblonga root extract (SOE) was evaluated in a subchronic 90-day feeding study in rats. An

A. M. Flammang; G. L. Erexson; J. M. Mirwald; S. M. Henwood

2007-01-01

346

Novel in vitro respiratory models to study lung development, physiology, pathology and toxicology  

PubMed Central

Detailed studies of lung pathology in patients during the course of development of acute lung injury or respiratory distress are limited, and in the past information related to lung-specific responses has been derived from the study of lungs from patients who died at autopsy or from animal models. Development of good in vitro human tissue models would help to bridge the gap in our current knowledge of lung responses and provide a better understanding of lung development, physiology and pathology. In vitro models of simple one-cell or two-cell culture systems as well as complex multicellular lung analogs that reproduce defined components of specific human lung responses have already been realized. A benefit of current in vitro lung models is that hypotheses generated from review of data from human or animal disease studies can be tested directly in engineered human tissue models. Results of studies done using simple in vitro lung systems or more complex three-dimensional models have already been used to examine cell-based responses, physiologic functions, pathologic changes and even drug toxicity or drug responses. In the future we will create models with specific genetic profiles to test the importance of single gene products or pathways of significance. Recent development of microfluidics-based models that support high-throughput screening will allow early-stage toxicity testing in human systems and faster development of new and innovative medical products. Model design in the future will also allow for evaluation of multiple organ systems at once, providing a more holistic or whole-body approach to understanding human physiology and responses.

2013-01-01

347

Toxicological and cytogenetic assessment of a Salacia oblonga extract in a rat subchronic study.  

PubMed

Salacia oblonga holds potential as a natural method to mitigate the blood glucose response for people with diabetes by inhibiting the activity of intestinal alpha-glucosidases. As part of a safety evaluation of novel ingredients for use in blood glucose control, the toxicity of a S. oblonga root extract (SOE) was evaluated in a subchronic 90-day feeding study in rats. An in vivo-in vitro rat peripheral blood lymphocyte chromosomal aberrations assay was added at termination of the subchronic rat study to examine cultured lymphocytes for possible chromosomal aberration induction. This was conducted due to a previous weak; although reproducible, positive chromosomal aberrations response in cultured peripheral blood human lymphocytes after acute in vitro treatment with SOE. The present study results indicate that SOE was negative for the induction of chromosomal aberrations in cultured rat peripheral blood lymphocytes after 90 consecutive days of treatment with SOE. The no observable adverse effect level (NOAEL) was determined to be 2,500 mg/kg/day following daily subchronic oral gavage administrations to rats. PMID:17566623

Flammang, A M; Erexson, G L; Mirwald, J M; Henwood, S M

2007-10-01

348

System Vaccinology for the Evaluation of Influenza Vaccine Safety by Multiplex Gene Detection of Novel Biomarkers in a Preclinical Study and Batch Release Test  

PubMed Central

Vaccines are beneficial and universal tools to prevent infectious disease. Thus, safety of vaccines is strictly evaluated in the preclinical phase of trials and every vaccine batch must be tested by the National Control Laboratories according to the guidelines published by each country. Despite many vaccine production platforms and methods, animal testing for safety evaluation is unchanged thus far. We recently developed a systems biological approach to vaccine safety evaluation where identification of specific biomarkers in a rat pre-clinical study evaluated the safety of vaccines for pandemic H5N1 influenza including Irf7, Lgals9, Lgalsbp3, Cxcl11, Timp1, Tap2, Psmb9, Psme1, Tapbp, C2, Csf1, Mx2, Zbp1, Ifrd1, Trafd1, Cxcl9, ?2m, Npc1, Ngfr and Ifi47. The current study evaluated whether these 20 biomarkers could evaluate the safety, batch-to-batch and manufacturer-to-manufacturer consistency of seasonal trivalent influenza vaccine using a multiplex gene detection system. When we evaluated the influenza HA vaccine (HAv) from four different manufactures, the biomarker analysis correlated to findings from conventional animal use tests, such as abnormal toxicity test. In addition, sensitivity of toxicity detection and differences in HAvs were higher and more accurate than with conventional methods. Despite a slight decrease in body weight caused by HAv from manufacturer B that was not statistically significant, our results suggest that HAv from manufacturer B is significantly different than the other HAvs tested with regard to Lgals3bp, Tapbp, Lgals9, Irf7 and C2 gene expression in rat lungs. Using the biomarkers confirmed in this study, we predicted batch-to-batch consistency and safety of influenza vaccines within 2 days compared with the conventional safety test, which takes longer. These biomarkers will facilitate the future development of new influenza vaccines and provide an opportunity to develop in vitro methods of evaluating batch-to-batch consistency and vaccine safety as an alternative to animal testing.

Mizukami, Takuo; Momose, Haruka; Kuramitsu, Madoka; Takizawa, Kazuya; Araki, Kumiko; Furuhata, Keiko; Ishii, Ken J.; Hamaguchi, Isao; Yamaguchi, Kazunari

2014-01-01

349

Pre-clinical studies of toxin-specific nanobodies: evidence of in vivo efficacy to prevent fatal disturbances provoked by scorpion envenoming.  

PubMed

Scorpions represent a significant threat to humans and animals in various countries throughout the world. Recently, we introduced Nanobodies (Nbs) to combat more efficiently scorpion envenoming and demonstrated the performance of NbAahIF12 and NbAahII10 to neutralize scorpion toxins of Androctonus australis hector venom. A bispecific Nb construct (NbF12-10) comprising these two Nbs is far more protective than the classic Fab'(2) based therapy and is the most efficient antivenom therapy against scorpion sting in preclinical studies. Now we investigate the biodistribution and pharmacokinetics of (99m)Tc labeled Nbs by in vivo imaging in rodents and compared these data with those of the Fab'(2) product (PAS). The pharmacodynamics of the Nbs was investigated in rats by in vivo echocardiography and it is shown that NbF12-10 prevents effectively the hemodynamic disturbances induced by a lethal dose of venom. Moreover, even a late injection of NbF12-10 restores the heart rate and brings the blood pressure to baseline values. Histology confirms that NbF12-10 prevents lung and heart lesions of treated mice after envenoming. In conjunction, in this preclinical study, we provide proof of concept that NbF12-10 prevents effectively the fatal disturbances induced by Androctonus venom, and that the Nanobody based therapeutic has a potential to substitute the classic Fab'(2) based product as immunotherapeutic in scorpion envenoming. Further clinical study using larger cohorts of animals should be considered to confirm the full protecting potential of our NbF12-10. PMID:22968189

Hmila, Issam; Cosyns, Bernard; Tounsi, Hayfa; Roosens, Bram; Caveliers, Vicky; Abderrazek, Rahma Ben; Boubaker, Samir; Muyldermans, Serge; El Ayeb, Mohamed; Bouhaouala-Zahar, Balkiss; Lahoutte, Tony

2012-10-15

350

Pre-clinical studies of toxin-specific Nanobodies: Evidence of in vivo efficacy to prevent fatal disturbances provoked by scorpion envenoming  

SciTech Connect

Scorpions represent a significant threat to humans and animals in various countries throughout the world. Recently, we introduced Nanobodies (Nbs) to combat more efficiently scorpion envenoming and demonstrated the performance of NbAahIF12 and NbAahII10 to neutralize scorpion toxins of Androctonus australis hector venom. A bispecific Nb construct (NbF12-10) comprising these two Nbs is far more protective than the classic Fab?{sub 2} based therapy and is the most efficient antivenom therapy against scorpion sting in preclinical studies. Now we investigate the biodistribution and pharmacokinetics of {sup 99m}Tc labeled Nbs by in vivo imaging in rodents and compared these data with those of the Fab?{sub 2} product (PAS). The pharmacodynamics of the Nbs was investigated in rats by in vivo echocardiography and it is shown that NbF12-10 prevents effectively the hemodynamic disturbances induced by a lethal dose of venom. Moreover, even a late injection of NbF12-10 restores the heart rate and brings the blood pressure to baseline values. Histology confirms that NbF12-10 prevents lung and heart lesions of treated mice after envenoming. In conjunction, in this preclinical study, we provide proof of concept that NbF12-10 prevents effectively the fatal disturbances induced by Androctonus venom, and that the Nanobody based therapeutic has a potential to substitute the classic Fab?{sub 2} based product as immunotherapeutic in scorpion envenoming. Further clinical study using larger cohorts of animals should be considered to confirm the full protecting potential of our NbF12-10. -- Highlights: ? Nanobody therapy prevents the hemodynamic disturbances induced by a lethal dose. ? Late injection of Nanobody restores hemodynamic parameters to baseline values. ? Nanobody therapy prevents lung and heart lesions of treated mice after envenoming. ? Labeled Nanobody and Fab’2 pharmacokinetics curves reach plateau in favour of Nanobody.

Hmila, Issam [Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis (Tunisia)] [Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis (Tunisia); Cosyns, Bernard [Laboratory of In Vivo Cellular and Molecular Imaging, Vrije Universiteit Brussel (Belgium)] [Laboratory of In Vivo Cellular and Molecular Imaging, Vrije Universiteit Brussel (Belgium); Tounsi, Hayfa [Service d'Anatomo-Pathologie, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis (Tunisia)] [Service d'Anatomo-Pathologie, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis (Tunisia); Roosens, Bram; Caveliers, Vicky [Laboratory of In Vivo Cellular and Molecular Imaging, Vrije Universiteit Brussel (Belgium)] [Laboratory of In Vivo Cellular and Molecular Imaging, Vrije Universiteit Brussel (Belgium); Abderrazek, Rahma Ben [Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis (Tunisia)] [Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis (Tunisia); Boubaker, Samir [Service d'Anatomo-Pathologie, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis (Tunisia)] [Service d'Anatomo-Pathologie, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis (Tunisia); Muyldermans, Serge [Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel (Belgium) [Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel (Belgium); Department of Structural Biology, VIB, Brussels (Belgium); El Ayeb, Mohamed [Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis (Tunisia)] [Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis (Tunisia); Bouhaouala-Zahar, Balkiss, E-mail: balkiss.bouhaouala@pasteur.rns.tn [Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis (Tunisia) [Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis (Tunisia); Faculté de Médecine de Tunis, Université de Tunis-El Manar (Tunisia); Lahoutte, Tony [Laboratory of In Vivo Cellular and Molecular Imaging, Vrije Universiteit Brussel (Belgium)] [Laboratory of In Vivo Cellular and Molecular Imaging, Vrije Universiteit Brussel (Belgium)

2012-10-15

351

Nonclinical toxicology studies with zidovudine: genetic toxicity tests and carcinogenicity bioassays in mice and rats.  

PubMed

Zidovudine (ZDV), an antiviral drug active in the treatment of acquired immunodeficiency syndrome (recommended human dose, 100 mg every 4 hr while awake), was evaluated for mutagenic and carcinogenic potential in a battery of short-term in vitro and in vivo assays and in lifetime studies in mice and rats. In L5178Y mouse lymphoma cells (tk+/- locus), a weak positive result was obtained only at the highest concentrations tested (4000 to 5000 micrograms/ml) in the absence of metabolic activation. In the presence of metabolic activation, the drug was weakly mutagenic at concentrations of 1000 micrograms/ml and higher. Following 24 hr treatment in the absence of metabolic activation, ZDV was moderately mutagenic at concentrations up to 600 micrograms/ml; dose-related structural chromosomal alterations were seen at concentrations of 3 micrograms/ml and higher in cultured human lymphocytes. Such effects were not noted at the two lowest concentrations tested, 0.3 and 1 microgram/ml, and BALB/c-3T3 cells were transformed at concentrations of 0.5 microgram/ml and higher. No effects were seen in the Ames Salmonella plate incorporation and preincubation modification assays (possibly due to bacteriocidal activity of ZDV at low concentrations) at concentrations ranging from 0.01 to 10 micrograms/plate or in a single-dose intravenous bone marrow cytogenetic assay in CD rats. In multidose micronucleus studies, increases in micronucleated erythrocytes were seen in mice at doses of 100 to 1000 mg/kg/day. Similar results were seen in rats and mice after 4 or 7 days of dosing at 500 mg/kg/day. In carcinogenicity bioassays, adjusted doses of 20, 30, or 40 mg/kg/day and 80, 220, and 300 mg/kg/day were given to CD-1 mice and CD rats, respectively, for up to 22 months in mice and 24 months in rats. ZDV caused a macrocytic, normochromic anemia in both species. No evidence of carcinogenicity was seen in male mice or rats. In female mice, five malignant and two benign vaginal epithelial neoplasms occurred in animals given 40 mg/kg/day. A single benign vaginal epithelial tumor was seen in a mouse given 30 mg/kg/day. In rats, two malignant vaginal epithelial neoplasms were seen in animals given 300 mg/kg/day. In a 7-day study in mice, ZDV was shown to be devoid of estrogenic activity. In an oral pharmacokinetics study, the AUC was 17 and 140 micrograms/ml.hr in female mice and rats given 40 or 300 mg/kg of ZDV, respectively. In contrast, the average steady-state concentration in humans at the recommended daily dose is 0.62 microgram/ml. Twenty-four hour urine concentrations were 1245 and 4417 micrograms/ml in female mice and rats given 40 or 300 mg/kg of ZDV, respectively. These values were approximately 26- and 136-fold higher than the human urine concentration at the recommended daily dose. In a one- to three-day study with intravenously administered sodium fluoroscein in rats and mice, retrograde flow of urine into the vagina was demonstrated. In a subsequent lifetime carcinogenicity bioassay in mice in which ZDV was given intravaginally at concentrations of 5 or 20 mg ZDV/ml in saline, 13 vaginal squamous cell carcinomas were seen at the highest concentration tested. It was concluded that the vaginal tumors seen in the oral carcinogenicity studies were the result of chronic local exposure of the vaginal epithelium to high urine concentrations of ZDV. PMID:8921318

Ayers, K M; Clive, D; Tucker, W E; Hajian, G; de Miranda, P

1996-08-01

352

Toxicological studies on Amfenac sodium (AHR-5850) (I) Acute toxicities in mice and rats.  

PubMed

Acute toxicities of Amfenac sodium (AHR-5850), new nonsteroidal anti-inflammatory agent, were studied in mice and rats. Each value of LD50 by oral, sc, im, iv and ip administration with this compound was 1190, 580, 540, 550 and 790 mg/kg for male mice and 1450, 625, 610, 630 and 710 mg/kg for female mice, respectively. Rats showed higher lethality than mice. There was no significant difference of sex in the values of LD50 for mice and rats. Movement and respiration rate followed by gastrointestinal ulcer, secondary peritonitis and systemic emaciation. These results suggest that the death is caused by secondary peritonitis and systemic emaciation due to gastrointestinal ulcer. PMID:6471132

Sasaki, H; Odaki, M; Yokota, M; Kawaoto, H; Watanabe, H; Itoh, T; Ishiwatari, N; Wada, T; Seki, M; Takeda, U

1984-02-01

353

[A retrospective study analysis of urinary hippuric acid levels in occupational toxicology exams].  

PubMed

Hippuric acid is the primary metabolite of toluene, a solvent widely used in industrial processes with considerable toxic effects, a fact which justifies regularly monitoring individuals with occupational exposure to this solvent. This work aims at evaluating urinary hippuric acid levels found in workers subject to biological monitoring. A retrospective study was carried out with data referring from 2002 to 2005, in which exams results and employment status were analyzed (periodic, post-employment, and pre-employment exams). Results indicate a significant reduction in hippuric acid levels for 2005. Periodic exams presented higher results than pre-employment and post-employment exams. No significant difference was found in individuals grouped according to their status in each of the established intervals, their reference numbers, and maximum biological levels allowed. Hippuric acid levels detected indicate low risk of toluene exposure for the population under evaluation, probably due to a growing concern with the deployment of measures regarding occupational hygiene. PMID:20640325

Gonzalez, Kelly Cristina; Sagebin, Fernando Rodrigues; Oliveira, Paola Garcia; Glock, Luiz; Thiesen, Flavia Valladão

2010-06-01

354

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

2012-01-01

355

Porcine adipose-derived stem cells from buccal fat pad and subcutaneous adipose tissue for future preclinical studies in oral surgery  

PubMed Central

Introduction Adipose-derived stem cells (ASCs) are progenitor cells used in bone tissue engineering and regenerative medicine. Despite subcutaneous adipose tissue being more abundant, the buccal fat pad (BFP) is easily accessible for dentists and maxillofacial surgeons. For this reason, considering the need for preclinical study and the swine as an optimal animal model in tissue engineering applications, we compared the features of porcine ASCs (pASCs) from both tissue-harvesting sites. Methods ASCs were isolated from interscapular subcutaneous adipose tissue (ScI) and buccal fat pads of six swine. Cells were characterized for their stemness and multipotent features. Moreover, their osteogenic ability when cultured on titanium disks and silicon carbide-plasma-enhanced chemical vapor-deposition fragments, and their growth in the presence of autologous and heterologous serum were also assessed. Results Independent of the harvesting site, no differences in proliferation, viability, and clonogenicity were observed among all the pASC populations. Furthermore, when induced toward osteogenic differentiation, both ScI- and BFP-pASCs showed an increase of collagen and calcified extracellular matrix (ECM) production, alkaline phosphatase activity, and osteonectin expression, indicating their ability to differentiate toward osteoblast-like cells. In addition, they differentiated toward adipocyte-like cells, and chondrogenic induced pASCs were able to increase glycosaminoglycans (GAGs) production over time. When cells were osteoinduced on synthetic biomaterials, they significantly increased the amount of calcified ECM compared with control cells; moreover, titanium showed the osteoinductive effect on pASCs, also without chemical stimuli. Finally, these cells grew nicely in 10% FBS, and no benefits were produced by substitution with swine serum. Conclusions Swine buccal fat pad contains progenitor cells with mesenchymal features, and they also osteo-differentiate nicely in association with synthetic supports. We suggest that porcine BFP-ASCs may be applied in preclinical studies of periodontal and bone-defect regeneration.

2013-01-01

356

Learning and confirming with preclinical studies: modeling and simulation in the discovery of GDC-0917, an inhibitor of apoptosis proteins antagonist.  

PubMed

The application of modeling and simulation techniques is increasingly common in the preclinical stages of the drug development process. GDC-0917 [(S)-1-((S)-2-cyclohexyl-2-((S)-2-(methylamino)propanamido)acetyl)-N-(2-(oxazol-2-yl)-4-phenylthiazol-5-yl)pyrrolidine-2-carboxamide] is a potent second-generation antagonist of inhibitor of apoptosis (IAP) proteins that is being developed for the treatment of various cancers. GDC-0917 has low to moderate clearance in the mouse (12.0 ml/min/kg), rat (27.0 ml/min/kg), and dog (15.3 ml/min/kg), and high clearance in the monkey (67.6 ml/min/kg). Accordingly, oral bioavailability was lowest in monkeys compared with other species. Based on our experience with a prototype molecule with similar structure, in vitro-in vivo extrapolation was used to predict a moderate clearance (11.5 ml/min/kg) in humans. The predicted human volume of distribution was estimated using simple allometry at 6.69 l/kg. Translational pharmacokinetic-pharmacodynamic (PK-PD) analysis using results from MDA-MB-231-X1.1 breast cancer xenograft studies and predicted human pharmacokinetics suggests that ED50 and ED90 targets can be achieved in humans using acceptable doses (72 mg and 660 mg, respectively) and under an acceptable time frame. The relationship between GDC-0917 concentrations and pharmacodynamic response (cIAP1 degradation) was characterized using an in vitro peripheral blood mononuclear cell immunoassay. Simulations of human GDC-0917 plasma concentration-time profile and cIAP1 degradation at the 5-mg starting dose in the phase 1 clinical trial agreed well with observations. This work shows the importance of leveraging information from prototype molecules and illustrates how modeling and simulation can be used to add value to preclinical studies in the early stages of the drug development process. PMID:24041744

Wong, Harvey; Gould, Stephen E; Budha, Nageshwar; Darbonne, Walter C; Kadel, Edward E; La, Hank; Alicke, Bruno; Halladay, Jason S; Erickson, Rebecca; Portera, Chia; Tolcher, Anthony W; Infante, Jeffery R; Mamounas, Michael; Flygare, John A; Hop, Cornelis E C A; Fairbrother, Wayne J

2013-12-01

357

Added risk and inverse estimation for count responses in reproductive aquatic toxicology studies.  

PubMed

One of the experimental designs used to evaluate the toxicity of certain chemicals in aquatic organisms focuses on reproductive output. Toxic effects are manifested through a reduced level of reproduction in exposed organisms. Historically, evaluating risks in this context has focused on changes in the mean reproduction in a population of organisms. In this paper, we focus on the toxic effects at the level of the individual organism. This new method for count responses involves added risk, the probability of the production of young being suppressed below certain specified levels in individuals exposed to a particular concentration level relative to the probability of that level of suppression in control organisms. This probability serves as the basis of the individual-based risk estimation procedures. In particular, inverse estimation of the concentration associated with a specified added risk and estimates of the added risk associated with a particular concentration are discussed in the context of a negative binomial regression model. Confidence intervals are constructed for both of these quantities using the delta method. These methods are illustrated with a study of an aquatic organism, Ceriodaphnia dubia, exposed to the herbicide nitrofen. PMID:9544508

See, K; Bailer, A J

1998-03-01

358

Gold(III)-dithiocarbamato anticancer agents: activity, toxicology and histopathological studies in rodents.  

PubMed

Gold(III)-dithiocarbamato complexes have recently gained increasing attention as potential anticancer agents because of their strong tumor cell growth--inhibitory effects, generally achieved by exploiting non-cisplatin-like mechanisms of action. The rationale of our research work is to combine the antitumor properties of the gold(III) metal center with the potential chemoprotective function of coordinated dithiocarbamates in order to reduce toxic side effects (in particular nephrotoxicity) induced by clinically established platinum-based drugs. In this context, [Au(III) Br(2) (ESDT)] (AUL12) was proved to exert promising and outstanding antitumor activity in vitro and to overcome both acquired and intrinsic resistance showed by some types of tumors toward cisplatin. As a subsequent extension of our previous work, we here report on detailed in vivo studies in rodents, including antitumor activity toward three transplantable murine tumor models, toxicity, nephrotoxicity and histopathological investigations. Remarkably, the gold(III) complex AUL12 stands out for higher anticancer activity than cisplatin toward all the murine tumor models examined, inducing up to 80% inhibition of tumor growth. In addition, it shows low acute toxicity levels (lethal dose, LD(50) = 30 mg kg(-1) ) and reduced nephrotoxicity. Altogether, these results confirm the reliability of our drug design strategy and support the validation of this gold(III)-dithiocarbamato derivative as a suitable candidate for clinical trials. PMID:20853318

Marzano, Cristina; Ronconi, Luca; Chiara, Federica; Giron, Maria Cecilia; Faustinelli, Ivo; Cristofori, Patrizia; Trevisan, Andrea; Fregona, Dolores

2011-07-15

359

Toxicological studies for some agricultural waste extracts on mosquito larvae and experimental animals  

PubMed Central

Objective To evaluate some agricultural waste extracts as insecticide and their effects on enzyme activities in liver and kidney of male mice. Methods The insecticidal activity of five tested compounds (one crude extract and 4 waste compounds) was bioassay against the 3rd instars of the Culex pipiens (Cx. pipiens) larvae in the laboratory. The LC50 values of eucalyptol, apricot kernel, Rice bran, corn, black liquor and white liquor are 91.45, 1 166.1, 1 203.3, 21 449.65, 4 025.78 and 6 343.18 ppm, respectively. Selection of the compounds for the subsequent studies was not only dependent on LC50 values but also on the persistence of these wastes products on large scale. Results White and black liquor did not produce any gross effect at 200 mg/Kg body weight. No apparent toxic symptoms were observed in tested animals during the whole period of the experiment which run out for 14 days. No statistically significance was observed in the enzyme cholinesterase activity, the activities of liver enzymes and kidney function in treated mice with black and white liquors. While, no and slight inhibition was observed after the 2 weeks of treatment period with deltamethrin and fenitrothion reached to about 24% in plasma cholinesterase enzyme activity. Significantly increase in the activities of liver enzymes and kidney function in treated mice with deltamethrin and fenitrothion. Conclusions Black liquor can be used efficiently to control Cx. pipiens larvae under laboratory condition. Environmental problem caused by rice straw can be solved by converting the waste material to beneficial natural selective insecticide.

El-Maghraby, Somia; Nawwar, Galal A; Bakr, Reda FA; Helmy, Nadia; Kamel, Omnia MHM

2012-01-01

360

[Toxicological studies on a new cephamycin, MT-141. I. Its acute toxicities in mice and rats].  

PubMed

Acute toxicities of MT-141 were studied in mice and rats to obtain the following results. LD50 value of MT-141 by i.v. administration was 6,100 mg/kg for male mice and 5,200 mg/kg for female mice. The LD50 value by i.m. administration was 8,200 mg/kg for the males and 8,600 mg/kg for the females, respectively. The mice administered with a lethal dose of MT-141 showed abnormal syndromes such as decreased spontaneous movement, decreased rate of respiration, ataxic gait, sedative state and loss of righting reflex, followed by a decrease of body weight. Gross inspection revealed no remarkable change in the organs and tissues of mice after a treatment with a lethal dose of MT-141. LD50 value of this compound was 6,600 mg/kg for male rats and 5,700 mg/kg for female rats by i.v. administration, 8,600 mg/kg for the males and 8,550 mg/kg for the females by i.p. administration, 9,600 mg/kg for the males and 9,700 mg/kg for the females by i.m. administration and more than 15,000 mg/kg for both sexes by s.c. or p.o. administration, respectively. The rats given a lethal dose of MT-141 showed abnormal syndromes such as stepping gait, face-down position, decreased rate of respiration, ataxic gait, decreased spontaneous movement and loss of righting reflex, followed by a decrease of body weight. The rats exhibited stretching behavior when given MT-141 through i.p. route and manifested vocalization when given it through s.c. and i.m. routes. The results of gross inspection and histopathological observation suggested that high doses of MT-141 induced slight renal toxicity in rats.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6434760

Kurebe, M; Yokota, M; Sasaki, H; Watanabe, H; Ito, T; Ishiwatari, N

1984-05-01

361

[Clinical toxicology of the Academy: yesterday, today and tomorrow].  

PubMed

National toxicology school of the Kirov Military Medical Academy, demonstrates the unity of clinical and experimental approaches related to one purpose throughout its history--saving human life and health from exposure to toxic substances of chemical nature. For more than three centuries the russian science of toxicology has been steadily developing, often ahead of the world science. It helped to create the means of protection and develop methods of treatment for chemical lesions. Currently, toxicology departments of military field therapy and military toxicology and medical protection are actively involved in the current study of military medicine, restructuring policy to provide toxicological aid in the Armed Forces, the development and introduction of Innovative methods of diagnosis and treatment of victims of toxicological etiology. PMID:24738280

Sofronov, G A; Khalimov, Iu Sh; Matveev, S Iu; Kuz'mich, V G; Fomichev, A V

2013-12-01

362

NTP Technical Report on the Toxicology and Carcinogenesis Studies of 2,3-Dibromo-1-Propanol (CAS No. 96-13-9) in F344/N Rats and B6C3F1 Mice (Dermal Studies).  

National Technical Information Service (NTIS)

2-3-Dibromo-1-propanol, a colorless liquid, has been used as a flame retardant, and as an intermediate in the manufacture of pesticides and pharmaceutical preparations. Toxicology and carcinogenicity studies were conducted by applying 2,3-dibromo-1-propan...

1993-01-01

363

Toxicology and Carcinogenesis Studies of C.I. Pigment Red 3 (CAS No. 2425-85-6) 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 60 rats of each sex diets containing 0, 6,000, 12,500, or 25,000 ppm C. I. Pigment Red 3. The appropriate feed was supplied weekly and available ad libitum for 103 weeks. U...

1992-01-01

364

Toxicology and Carcinogenesis Studies of 2,2-Bis(Bromomethyl) -1,3-Propanediol (FR-1138 (Trade Name)) (CAS. No. 3296-90-0) in F344/N Rats and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenicity studies were conducted by administering 2,2-bis(bromomethyl) -1,3-propanediol to groups of 60 F344/N rats of eachsex in feed at exposures of 0, 2,500, 5,000 or 10,000 for 104 to 105 weeks. Nine or ten control animals and fiv...

1996-01-01

365

NTP Technical Report on Toxicology and Carcinogenesis Studies of o-Benzyl-p-Chlorophenol (CAS No. 120-32-1) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Two year toxicology and carcinogenicity studies were conducted by administering o-benzyl-p-chlorophenol to groups of 80 male and female rats in corn oil by gavage for 103 weeks at doses of 0, 30, 60, or 120 mg/kg body weight for male rats and 0, 60, 120, ...

1994-01-01

366

Toxicology and Carcinogenesis Studies of HC Red No. 3 (2,-((4-Amino-2-Nitrophenyl)Amino)Ethanol) (CAS No. 2871-01-4) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies of HC Red No. 3 (97% pure), a semipermanent hair dye, were conducted by administering the chemical in corn oil by gavage for 105 weeks to groups of 50 male and 50 female F344/N rats and for 104 weeks to groups of 50 m...

1986-01-01

367

Toxicology and Carcinogenesis Studies of 2-Amino-4-Nitrophenol (CAS NO. 99-57-0) in F344/N Rats and B6C3F1 Mice (Gavage Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies of 2-amino-4-nitrophenol, which is used to color hair dyes, were conducted by administering the chemical in corn oil by gavage to groups of 50 F344/N rats of each sex and 50 B6C3F1 mice of each sex at doses o...

1988-01-01

368

Toxicology and Carcinogenesis Studies of HC Blue No. 1 (CAS No. 2784-94-3) in F344/N Rats and B6C3F1 Mice. (Feed Studies).  

National Technical Information Service (NTIS)

Toxicology and carcinogenesis studies of HC Blue No. 1 (97% pure), a semipermanent hair dye, were conducted by administering the test chemical in feed for 103 weeks to groups of 50 F344/N rats and 50 B6C3F1 mice of each sex. The dietary concentrations use...

1985-01-01

369

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

370

NTP Technical Report on the Toxicology and Carcinogenesis Studies of Oxazepam (CAS No. 604-75-1) in Swiss-Webster and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Two-year toxicology and carcinogenesis studies were performed by administering oxazepam (greater than 99% pure) in feed to groups of 60 male and 60 female Swiss-Webster and B6C3F1 mice at concentrations of 0, 2,500, or 5,000 ppm, for 57 weeks (Swiss-Webst...

1993-01-01

371

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

372

Organic lead toxicology.  

PubMed

Lead is one of the oldest known and most widely studied occupational and environmental poison. Despite intensive study, there is still debate about the toxic effects of lead, both from low-level exposure in the general population owing to environmental pollution and historic use of lead in paint and plumbing and from exposure in the occupational setting. Significant position have organic lead compounds used more than 60 years as antiknock additives in gasoline. Chemical and toxicological characteristics of main tetraalkyl leads used as gasoline additives are discussed in this article. The majority of industries historically associated with high lead exposure have made dramatic advances in their control of occupational exposure. However, cases of unacceptably high exposure and even of frank lead poisoning are still seen, predominantly in the demolition and tank cleaning industries. Nevertheless, in most industries blood lead levels have declined below levels at which signs or symptoms are seen and the current focus of attention is on the subclinical effects of exposure. The significance of some of these effects for the overt health of the workers is often the subject of debate. Inevitably there is pressure to reduce lead exposure in the general population and in working environments, because current studies show that no level of lead exposure appears to be a 'safe' and even the current 'low' levels of exposure, especially in children, are associated with neurodevelopmental deficits. PMID:19453086

Patocka, Jirí

2008-01-01

373

Comparative Effectiveness of 3-Dimensional vs 2-Dimensional and High-Definition vs Standard-Definition Neuroendoscopy: A Preclinical Randomized Crossover Study  

PubMed Central

BACKGROUND: Although the potential benefits of 3-dimensional (3-D) vs 2-dimensional (2-D) and high-definition (HD) vs standard-definition (SD) endoscopic visualization have long been recognized in other surgical fields, such endoscopes are generally considered too large and bulky for use within the brain. The recent development of 3-D and HD neuroendoscopes may therefore herald improved depth perception, better appreciation of anatomic details, and improved overall surgical performance. OBJECTIVE: To compare simultaneously the effectiveness of 3-D vs 2-D and HD vs SD neuroendoscopy. METHODS: Ten novice neuroendoscopic surgeons were recruited from a university hospital. A preclinical randomized crossover study design was adopted to compare 3-D vs 2-D and HD vs SD neuroendoscopy. The primary outcomes were time to task completion and accuracy. The secondary outcomes were perceived task workload using the NASA (National Aeronautics and Space Administration) Task Load Index and subjective impressions of the endoscopes using a 5-point Likert scale. RESULTS: Time to task completion was significantly shorter when using the 3-D vs the 2-D neuroendoscopy (P = .001), and accuracy of probe placement was significantly greater when using the HD vs the SD neuroendoscopy (P = .009). We found that 3-D endoscopy significantly improved perceived depth perception (P < .001), HD endoscopy significantly improved perceived image quality (P < .001), and both improved participants’ overall impression (P < .001). CONCLUSION: Three-dimensional neuroendoscopy and HD neuroendoscopy have differing but complementary effects on surgical performance, suggesting that neither alone can completely compensate for the lack of the other. There is therefore strong preclinical evidence to justify 3-D HD neuroendoscopy. ABBREVIATIONS: HD, high definition SD, standard definition

Hughes-Hallett, Archie; Cundy, Thomas P.; Di Marco, Aimee; Pratt, Philip; Nandi, Dipankar; Darzi, Ara; Yang, Guang-Zhong

2013-01-01

374

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

2010-01-01

375

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

2012-02-01

376

Pre-clinical safety evaluation of soluble glucan.  

PubMed

Soluble glucan, a beta-1,3-linked glucopyranose biological response modifier, is effective in the therapy of experimental neoplasia, infectious diseases and immune suppression. Currently, soluble glucan is undergoing phase I clinical trials. The present study describes the pre-clinical safety evaluation of soluble glucan in mice, rats, guinea pigs and rabbits. ICR/HSD mice and Harlan Sprague-Dawley rats received a single i.v. injection of soluble glucan in doses ranging from 40 to 1000 mg/kg. Soluble glucan administration did not induce mortality, appearance or behavioral changes in mice or rats. In subsequent studies, mice and guinea pigs were injected i.p. with glucan (250 mg/kg) for 7 consecutive days. ICR/HSD mice gained weight at the same rate as the saline-treated controls. In contrast, guinea pigs receiving i.p. injections of soluble glucan showed a significant (P less than 0.05) 10-13% decrease in weight gain over the 7 day period. No other toxicologic, behavioral or appearance changes were noted. To examine chronic toxicity, soluble glucan was administered twice weekly for a period of 30 or 60 days to ICR/HSD mice in the dose of 40, 200 or 1000 mg/kg. No deaths were observed in any group. Chronic glucan administration did not alter body weight, liver, lung or kidney weight. However, a significant splenomegaly was observed in both the 30 and 60 day study. Histopathologic examination showed no tissue alterations at 40 or 200 mg/kg. However, at 1000 mg/kg a mononuclear infiltrate was observed in the liver. Pyrogenicity testing, employing New Zealand white rabbits, revealed that parenteral glucan administration (5 mg/kg) did not significantly alter body temperature. These data indicate that the systemic administration of soluble glucan, over a wide dose range, does not induce mortality or significant toxicity, an important consideration in preparing soluble glucan for parenteral administration to human populations. PMID:3262594

Williams, D L; Sherwood, E R; Browder, I W; McNamee, R B; Jones, E L; Di Luzio, N R

1988-01-01

377

Biodegradation of Rubine GFL by Galactomyces geotrichum MTCC 1360 and subsequent toxicological analysis by using cytotoxicity, genotoxicity and oxidative stress studies.  

PubMed

Galactomyces geotrichum MTCC 1360 showed 87?% decolorization of the azo dye Rubine GFL (50 mg l(-1)) within 96 h at 30 °C and pH 7.0 under static conditions, with significant reduction of chemical oxygen demand (67?%) and total organic carbon (59?%). Examination of oxidoreductive enzymes, namely laccase, tyrosinase and azo reductase, confirmed their role in decolorization and degradation of Rubine GFL. Biodegradation of Rubine GFL into different metabolites was confirmed using high-performance TLC, HPLC, Fourier transform IR spectroscopy and GC-MS analysis. During toxicological studies, cell death was observed in Rubine GFL-treated Allium cepa root cells. Toxicological studies before and after microbial treatment were done with respect to cytotoxicity, genotoxicity, oxidative stress, antioxidant enzyme status, protein oxidation and lipid peroxidation using root cells of A. cepa. The analysis with A. cepa showed that the dye exerts oxidative stress and subsequently has a toxic effect on the root cells, whereas its metabolites are less toxic. Phytotoxicity studies revealed the less toxic nature of the metabolites as compared with Rubine GFL. PMID:22723285

Waghmode, Tatoba R; Kurade, Mayur B; Kabra, Akhil N; Govindwar, Sanjay P

2012-09-01

378

Oral-toxicology.  

PubMed

Forensic toxicology deals with the investigation of toxic substances, poisonous products or with the environmental chemicals. This field of science helps to identify poison substance and hazardous chemicals. Forensic toxicology deals with the way that substances are absorbed, distributed or eliminated in the body - the metabolism of substances. This paper reviews the manifestations that each poisonous substance presents concentrating toward the commonly used poisonous substance especially in India. It also explains the Indian Penal Code, which is main criminal code intended to cover all substantive aspects of criminal law regarding poison. PMID:24696586

Gowda, B K Charan; Sundharam, B Sivapatha; Mahadesh, Jyothi; Mukund

2014-01-01

379

TOXICOLOGY OF METALS. VOLUME II  

EPA Science Inventory

The report on metal toxicology contains reviews on twenty-three metals. These have been written for inclusion in a Handbook on the Toxicology of Metals: Environmental and Occupational Aspects which is being prepared by the Scientific Committee on the Toxicology of Metals of the P...

380

Preclinical cardiorenal interrelationships in essential hypertension.  

PubMed

A diseased heart causes numerous adverse effects on kidney function, and vice versa renal disease can significantly impair cardiac function. Beyond these heart-kidney interrelationships at the clinical level, a reciprocal association has been suggested to exist even in the early stages of those organs' dysfunction. The aim of the present review is to provide evidence of the presence of a preclinical cardiorenal syndrome in the particular setting of essential hypertension, focusing on the subsequent hypertensive sequelae on heart and kidneys. In particular, a plethora of studies have demonstrated not only the predictive role of kidney damage, as expressed by either decreased glomerular filtration or increased urine albumin excretion, for adverse left ventricular functional and structural adaptations but also preclinical heart disease, i.e. left ventricular hypertrophy that is associated with deterioration of renal function. Notably, these reciprocal interactions seem to exist even at the level of microcirculation, since both coronary flow reserve and renal hemodynamics are strongly related with clinical and preclinical renal and cardiac damage, respectively. In this preclinical setting, common pathophysiological denominators, including the increased hemodynamic load, sympathetic and renin-angiotensin system overactivity, increased subclinical inflammatory reaction, and endothelial dysfunction, account not only for the reported associations between overt cardiac and renal damage but also for the parallel changes that occur in coronary and renal microcirculation. PMID:23946723

Tsioufis, Costas; Tsiachris, Dimitrios; Kasiakogias, Alexandros; Dimitriadis, Kyriakos; Petras, Dimitris; Goumenos, Dimitris; Siamopoulos, Konstantinos; Stefanadis, Christodoulos

2013-04-01

381

Preclinical Cardiorenal Interrelationships in Essential Hypertension  

PubMed Central

A diseased heart causes numerous adverse effects on kidney function, and vice versa renal disease can significantly impair cardiac function. Beyond these heart-kidney interrelationships at the clinical level, a reciprocal association has been suggested to exist even in the early stages of those organs' dysfunction. The aim of the present review is to provide evidence of the presence of a preclinical cardiorenal syndrome in the particular setting of essential hypertension, focusing on the subsequent hypertensive sequelae on heart and kidneys. In particular, a plethora of studies have demonstrated not only the predictive role of kidney damage, as expressed by either decreased glomerular filtration or increased urine albumin excretion, for adverse left ventricular functional and structural adaptations but also preclinical heart disease, i.e. left ventricular hypertrophy that is associated with deterioration of renal function. Notably, these reciprocal interactions seem to exist even at the level of microcirculation, since both coronary flow reserve and renal hemodynamics are strongly related with clinical and preclinical renal and cardiac damage, respectively. In this preclinical setting, common pathophysiological denominators, including the increased hemodynamic load, sympathetic and renin-angiotensin system overactivity, increased subclinical inflammatory reaction, and endothelial dysfunction, account not only for the reported associations between overt cardiac and renal damage but also for the parallel changes that occur in coronary and renal microcirculation.

Tsioufis, Costas; Tsiachris, Dimitrios; Kasiakogias, Alexandros; Dimitriadis, Kyriakos; Petras, Dimitris; Goumenos, Dimitris; Siamopoulos, Konstantinos; Stefanadis, Christodoulos

2013-01-01

382

Studies on the human metabolism and the toxicologic detection of the cough suppressant dropropizine in urine using gas chromatography-mass spectrometry.  

PubMed

Studies are described on the metabolism and the toxicologic analysis of the nonopioid cough suppressant dropropizine [R,S-3-(4-phenyl-1-piperazinyl)1,2-propandiol, DRO] in human urine using gas chromatography-mass spectrometry (GC-MS). The metabolism studies showed that DRO was metabolized in humans mainly by hydroxylation of the aromatic ring, by N-dealkylation of the parent drug and of the hydroxyl-metabolite to the corresponding N-phenylpiperazines, and by degradation of the piperazine moiety. The authors' systematic toxicologic analysis (STA) procedure using full-scan GC-MS after acid hydrolysis, liquid-liquid extraction, and microwave-assisted acetylation allowed the unambiguous detection of DRO and its above-mentioned metabolites in human urine up to about 32 hours after intake of a single common therapeutic dose. The target analytes were found to be the parent compound DRO (earlier phase of excretion) and the hydroxylated metabolite para-hydroxy-DRO (later phase of excretion). Both allowed unambiguous detection of an intake of DRO and also differentiation from other phenylpiperazine derivatives. PMID:15257075

Staack, Roland F; Theobald, Denis S; Maurer, Hans H

2004-08-01

383

NTP Toxicology and Carcinogenesis Studies of 3,3'-Dimethoxybenzidine Dihydrochloride (CAS No. 20325-40-0) in F344/N Rats (Drinking Water Studies).  

PubMed

3,3'-Dimethoxybenzidine dihydrochloride is an off-white powder with a melting point of 274 degrees C. 3,3'-Dimethoxybenzidine is used principally as an intermediate in the production of commercial bisazobiphenyl dyes for coloring textiles, paper, plastic, rubber, and leather. In the synthesis of the bisazobiphenyl dyes, the amine groups of 3,3'-dimethoxybenzidine are chemically linked with other aromatic amines. A small quantity of 3,3'-dimethoxybenzidine is also used as an intermediate in the production of o-dianisidine diisocyanate, which is used in isocyanate-based adhesive systems and as a component of polyurethane elastomers. 3,3'-Dimethoxybenzidine dihydrochloride was evaluated in toxicity and carcinogenicity studies as part of the National Toxicology Program's Benzidine Dye Initiative. This Initiative was designed to evaluate the representative benzidine congeners and benzidine congener-derived and benzidine-derived dyes. 3,3'-Dimethoxybenzidine dihydrochloride was nominated for study because of the potential for human exposure during production of bisazobiphenyl dyes and because benzidine, a structurally related chemical, is a known human carcinogen. NTP Toxicology and Carcinogenesis studies were conducted by administering 3,3'-dimethoxybenzidine dihydrochloride (greater than 97.5% pure) in drinking water to groups of F344/N rats of each sex for 14 days, 13 weeks, 9 months, or 21-months. The 21-month studies were intended to last 24 months but were terminated early because of rapidly declining survival due to neoplasia. Studies were performed only in rats because similar studies are being performed in mice at the National Center for Toxicology Research. Genetic toxicology studies were conducted with Salmonella typhimurium, Chinese hamster over (CHO) cells, and Drosophila melanogaster. Fourteen-Day Studies: All rats receiving drinking water concentrations up to 4,500 ppm lived to the end of the studies. Rats that received water containing 4,500 ppm 3,3'-dimethoxybenzidine dihydrochloride lost weight. Water consumption decreased with increasing concentration of chemical and at 4,500 ppm was less than one-fourth that by the controls. Lymphoid depletion of the thymus in males and hypocellularity of the bone marrow in males and females were seen at the 4,500-ppm concentration, but not at the next lower concentration or in controls. Thirteen-Week Studies: All rats receiving concentrations up to 2,500 ppm lived to the end of the studies. Final mean body weights of rats given drinking water containing 1,250 or 2,500 ppm 3,3'-dimethoxybenzidine dihydrochloride were 5%-20% lower than those of controls. Water consumption at these concentrations was 40%-60% that consumed by controls. Compound-related effects in rats given water containing 2,500 ppm 3,3'-dimethoxybenzidine dihydrochloride included a mind exacerbation of naturally occurring nephropathy and the presence of a yellow-brown pigment (lipofuscin) in the cytoplasm of thyroid follicular cells. Serum triiodothyronine (T3) and thyroxin (T4) concentrations in females receiving 330 ppm or more and T4 concentrations in males receiving 170 ppm or more were significantly lower than in controls. Thyrotropin (TSH) concentrations were comparable in controls and exposed rats. Based on the chemical-related nephropathy and reductions in water consumption and body weight gain observed in the 13-week studies, doses for the long-term studies in male and female rats were 0 or 330 ppm 3,3'-dimethoxybenzidine dihydrochloride in drinking water administered for 9 months and 0, 80, 170, or 330 ppm administered for 21 months. Nine-Month Studies: Ten rats of each sex in control and 330-ppm groups were evaluated after 9 months. Significant decreases in T3 and T4 concentrations were seen in exposed male and female rats. Other lesions seen in exposed rats included foci of alteration in the liver, a carcinoma of the preputial gland in one male, a carcinoma of the clitoral gland in one female, and carcinoma of the Zymbal gland in two males. Body Weights and Survival in the Twenty-One-Month Studie

1990-01-01

384

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

385

Toxicology of chlorofluorocarbon replacements.  

PubMed

Chlorofluorocarbons (CFCs) are stable in the atmosphere and may reach the stratosphere. They are cleaved by UV-radiation in the stratosphere to yield chlorine radicals, which are thought to interfere with the catalytic cycle of ozone formation and destruction and deplete stratospheric ozone concentrations. Due to potential adverse health effects of ozone depletion, chlorofluorocarbon replacements with much lower or absent ozone depleting potential are developed. The toxicology of these compounds that represent chlorofluorohydrocarbons (HCFCs) or fluorohydrocarbons (HFCs) has been intensively studied. All compounds investigated (1, 1-dichloro-1-fluoroethane [HCFC-141b], 1,1,1,2-tetrafluoroethane [HFC-134a], pentafluoroethane [HFC-125], 1-chloro- 1,2,2,2-tetrafluoroethane [HCFC-124], and 1,1-dichloro-2,2,2-trifluoroethane [HCFC-123]) show only a low potential for skin and eye irritation. Chronic adverse effects on the liver (HCFC-123) and the testes (HCFC-141b and HCFC-134a), including tumor formation, were observed in long-term inhalation studies in rodents using very high concentrations of these CFC replacements. All CFC replacements are, to varying extents, biotransformed in the organism, mainly by cytochrome P450-catalyzed oxidation of C-H bonds. The formed acyl halides are hydrolyzed to give excretable carboxylic acids; halogenated aldehydes that are formed may be further oxidized to halogenated carboxylic acids or reduced to halogenated alcohols, which are excretory metabolites in urine from rodents exposed experimentally to CFC replacements. The chronic toxicity of the CFC replacements studied is unlikely to be of relevance for humans exposed during production and application of CFC replacements. PMID:8722112

Dekant, W

1996-03-01

386

NTP Report on the Toxicology Studies of Aspartame (CAS NO. 22839-47-0) in Genetically Modified (FVB Tg.AC Hemizygous) and B6.129-Cdkn2a(tm1Rdp) (n2) Deficient Mice and Carcinogenicity Studies of Aspartame in Genetically Modified (B6.129-trp53(tm1Brd)(n5) Haploinsufficient) Mice (Feed Studies).  

National Technical Information Service (NTIS)

The studies described in this report are designed and conducted to characterize and evaluate the toxicologic potential, including carcinogenic activity, of selected chemicals in laboratory animals (usually two species, rats and mice). Chemicals selected f...

2005-01-01

387

Toxicology and Biodistribution Studies for MGH2.1, an Oncolytic Virus that Expresses Two Prodrug-activating Genes, in Combination with Prodrugs.  

PubMed

MGH2.1 is a herpes simplex virus type 1 (HSV1) oncolytic virus that expresses two prodrug-activating transgenes: the cyclophosphamide (CPA)-activating cytochrome P4502B1 (CYP2B1) and the CPT11-activating secreted human intestinal carboxylesterase (shiCE). Toxicology and biodistribution of MGH2.1 in the presence/absence of prodrugs was evaluated in mice. MGH2.1 ± prodrugs was cytotoxic to human glioma cells, but not to normal cells. Pharmacokinetically, intracranial MGH2.1 did not significantly alter the metabolism of intraperitoneally (i.p.) administered prodrugs in mouse plasma, brain, or liver. MGH2.1 did not induce an acute inflammatory reaction. MGH2.1 DNA was detected in brains of mice inoculated with 10(8) pfus for up to 60 days. However, only one animal showed evidence of viral gene expression at this time. Expression of virally encoded genes was restricted to brain. Intracranial inoculation of MGH2.1 did not induce lethality at 10(8) pfus in the absence of prodrugs and at 10(6) pfus in the presence of prodrugs. This study provides safety and toxicology data justifying a possible clinical trial of intratumoral injection of MGH2.1 with peripheral administration of CPA and/or CPT11 prodrugs in humans with malignant gliomas.Molecular Therapy-Nucleic Acids (2013) 2, e113; doi:10.1038/mtna.2013.38; published online 6 August 2013. PMID:23922029

Kasai, Kazue; Nakashima, Hiroshi; Liu, Fang; Kerr, Samantha; Wang, Jiang; Phelps, Mitch; Potter, Philip M; Goins, William B; Fernandez, Soledad A; Chiocca, E Antonio

2013-01-01

388

Toxicology and Biodistribution Studies for MGH2.1, an Oncolytic Virus that Expresses Two Prodrug-activating Genes, in Combination with Prodrugs  

PubMed Central

MGH2.1 is a herpes simplex virus type 1 (HSV1) oncolytic virus that expresses two prodrug-activating transgenes: the cyclophosphamide (CPA)-activating cytochrome P4502B1 (CYP2B1) and the CPT11-activating secreted human intestinal carboxylesterase (shiCE). Toxicology and biodistribution of MGH2.1 in the presence/absence of prodrugs was evaluated in mice. MGH2.1 ± prodrugs was cytotoxic to human glioma cells, but not to normal cells. Pharmacokinetically, intracranial MGH2.1 did not significantly alter the metabolism of intraperitoneally (i.p.) administered prodrugs in mouse plasma, brain, or liver. MGH2.1 did not induce an acute inflammatory reaction. MGH2.1 DNA was detected in brains of mice inoculated with 108 pfus for up to 60 days. However, only one animal showed evidence of viral gene expression at this time. Expression of virally encoded genes was restricted to brain. Intracranial inoculation of MGH2.1 did not induce lethality at 108 pfus in the absence of prodrugs and at 106 pfus in the presence of prodrugs. This study provides safety and toxicology data justifying a possible clinical trial of intratumoral injection of MGH2.1 with peripheral administration of CPA and/or CPT11 prodrugs in humans with malignant gliomas.

Kasai, Kazue; Nakashima, Hiroshi; Liu, Fang; Kerr, Samantha; Wang, Jiang; Phelps, Mitch; Potter, Philip M; Goins, William B; Fernandez, Soledad A; Chiocca, E Antonio

2013-01-01

389

A 28-day rat inhalation study with an integrated molecular toxicology endpoint demonstrates reduced exposure effects for a prototypic modified risk tobacco product compared with conventional cigarettes.  

PubMed

Towards a systems toxicology-based risk assessment, we investigated molecular perturbations accompanying histopathological changes in a 28-day rat inhalation study combining transcriptomics with classical histopathology. We demonstrated reduced biological activity of a prototypic modified risk tobacco product (pMRTP) compared with the reference research cigarette 3R4F. Rats were exposed to filtered air or to three concentrations of mainstream smoke (MS) from 3R4F, or to a high concentration of MS from a pMRTP. Histopathology revealed concentration-dependent changes in response to 3R4F that were irritative stress-related in nasal and bronchial epithelium, and inflammation-related in the lung parenchyma. For pMRTP, significant changes were seen in the nasal epithelium only. Transcriptomics data were obtained from nasal and bronchial epithelium and lung parenchyma. Concentration-dependent gene expression changes were observed following 3R4F exposure, with much smaller changes for pMRTP. A computational-modeling approach based on causal models of tissue-specific biological networks identified cell stress, inflammation, proliferation, and senescence as the most perturbed molecular mechanisms. These perturbations correlated with histopathological observations. Only weak perturbations were observed for pMRTP. In conclusion, a correlative evaluation of classical histopathology together with gene expression-based computational network models may facilitate a systems toxicology-based risk assessment, as shown for a pMRTP. PMID:24632068

Kogel, Ulrike; Schlage, Walter K; Martin, Florian; Xiang, Yang; Ansari, Sam; Leroy, Patrice; Vanscheeuwijck, Patrick; Gebel, Stephan; Buettner, Ansgar; Wyss, Christoph; Esposito, Marco; Hoeng, Julia; Peitsch, Manuel C

2014-06-01

390

Operational Toxicology Research.  

National Technical Information Service (NTIS)

This is a final report for the Operational Toxicology Research (OTR) Contract F33615-00-C-6060 initiated in March 2001 to support the Air Force Research Laboratory Applied Biotechnology Branch (AFRL/HEPB) at Wright- Patterson Air Force Base (WPAFB), OH. T...

D. E. Dodd D. R. Mattie M. A. Angell

2006-01-01

391

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

392

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

393

Ultrasound guided fluorescence molecular tomography with improved quantification by an attenuation compensated born-normalization and in vivo preclinical study of cancer  

NASA Astrophysics Data System (ADS)

Ultrasound imaging, having the advantages of low-cost and non-invasiveness over MRI and X-ray CT, was reported by several studies as an adequate complement to fluorescence molecular tomography with the perspective of improving localization and quantification of fluorescent molecular targets in vivo. Based on the previous work, an improved dual-modality Fluorescence-Ultrasound imaging system was developed and then validated in imaging study with preclinical tumor model. Ultrasound imaging and a profilometer were used to obtain the anatomical prior information and 3D surface, separately, to precisely extract the tissue boundary on both sides of sample in order to achieve improved fluorescence reconstruction. Furthermore, a pattern-based fluorescence reconstruction on the detection side was incorporated to enable dimensional reduction of the dataset while keeping the useful information for reconstruction. Due to its putative role in the current imaging geometry and the chosen reconstruction technique, we developed an attenuation compensated Born-normalization method to reduce the attenuation effects and cancel off experimental factors when collecting quantitative fluorescence datasets over large area. Results of both simulation and phantom study demonstrated that fluorescent targets could be recovered accurately and quantitatively using this reconstruction mechanism. Finally, in vivo experiment confirms that the imaging system associated with the proposed image reconstruction approach was able to extract both functional and anatomical information, thereby improving quantification and localization of molecular targets.

Li, Baoqiang; Berti, Romain; Abran, Maxime; Lesage, Frédéric

2014-05-01

394

TOXICOLOGICAL RESEARCH INVOLVING HUMANS: ETHICAL AND REGULATORY CONSIDERATIONS  

EPA Science Inventory

This paper discusses the need for the Society of Toxicology (SOT) to develop a policy for ethical research in humans, and a review for publication of these studies. Observations on human beings have been the foundation upon which toxicologic knowledge has been built since the in...

395

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

396

Synovial fluid: an alternative toxicologic specimen?  

PubMed

Although blood is the most commonly used specimen in forensic toxicology, it is not always available. In those cases, alternative samples are sought on which to perform toxicology testing. The current study assessed the usefulness of synovial fluid for postmortem cocaine and opiate/opioid testing. One hundred four cases were sampled, with 98 cases being tested representing 24 negative controls and 74 cases positive for cocaine, benzoylecgonine, morphine, 6-monoacetylmorphine, hydrocodone, and/or oxycodone. Synovium demonstrated excellent correlation and predictability when compared with blood, although it was not as sensitive for 6-monoacetylmorphine as either vitreous or urine. The authors recommend further study to assess the usefulness of synovial fluid in postmortem toxicology to include the evaluation of its utilize for more drugs and the development of further assays to use its potential even in limited quantities. PMID:24781403

Deking, Janine; Hargrove, Veronica M; Molina, D Kimberley

2014-06-01

397

[Detection of antibiotics in biological materials for purposes of toxicological analysis. I. Methodologic study for the detection of tetracycline].  

PubMed

A method of the identification of tetracycline antibiotics in urine and gastric content, suitable for the routine toxicological analysis, was worked out. For the isolation, the extraction with ethyl acetate is recommended. The TLC method on Silufol layers impregnated with an aqueous solution of the disodium salt of ethylenediaminetetraacetic acid (Na2EDTA), in the concentration of 0.1 mol/l and pH value of 5 or 7.4 is used for the identification. The mobile phase chloroform--methanol--Na2EDTA 55:30:5 is suitable for the development of these layers; UV light of the wavelength 254 or 366 nm and Fast Blue B reagent are used for the detection. The conditions of the TLC (various modifications of the layer, mobile phase and detection) and the extraction solvents suitable for the isolation are discussed. PMID:1821333

Nováková, E

1991-11-01

398

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 24 h) 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 24 h 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

2013-10-01

399

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

400

Preclinical Evaluation of HIV Eradication Strategies in the Simian Immunodeficiency Virus-Infected Rhesus Macaque: A Pilot Study Testing Inhibition of Indoleamine 2,3-Dioxygenase  

PubMed Central

Abstract Even in the setting of maximally suppressive antiretroviral therapy (ART), HIV persists indefinitely. Several mechanisms might contribute to this persistence, including chronic inflammation and immune dysfunction. In this study, we have explored a preclinical model for the evaluation of potential interventions that might serve to eradicate or to minimize the level of persistent virus. Given data that metabolic products of the inducible enzyme indoleamine 2,3-dioxygeanse (IDO) might foster inflammation and viral persistence, chronically simian immunodeficiency virus (SIV)-infected, ART-treated rhesus macaques were treated with the IDO inhibitor 1-methyl tryptophan (1mT). Orally administered 1mT achieved targeted plasma levels, but did not impact tryptophan metabolism or decrease viral RNA or DNA in plasma or in intestinal tissues beyond levels achieved by ART alone. Animals treated with 1mT showed no difference in the levels of T cell activation or differentiation, or in the kinetics or magnitude of viral rebound following cessation of ART. Notwithstanding these negative results, our observations suggest that the chronically SIV-infected rhesus macaque on suppressive ART can serve as a tractable model in which to test and to prioritize the selection of other potential interventions designed to eradicate HIV in vivo. In addition, this model might be used to optimize the route and dose by which such interventions are administered and the methods by which their effects are monitored.

Dunham, Richard M.; Gordon, Shari N.; Vaccari, Monica; Piatak, Michael; Huang, Yong; Deeks, Steven G.; Lifson, Jeffrey; Franchini, Genoveffa

2013-01-01