Polychlorinated biphenyl (PCB) induction of CYP3A4 enzyme activity in healthy Faroese adults

DEFF Research Database (Denmark)

Petersen, Maria Skaalum; Halling, Jónrit; Damkier, Per

2007-01-01

The CYP3A4 enzyme is, along with other cytochrome P450 enzymes, involved in the metabolism of environmental pollutants and is highly inducible by these substances. A commercial polychlorinated biphenyl (PCB) mixture, 1,1,1,-trichloro-2-(o-chlorophenyl), 2-(p'-chlorophenyl)ethane (o,p'-DDT) and 1......,1,-dichloro-2,2-bis (p-chlorophenyl)ethene (p,p'-DDE) are known to induce CYP3A4 activity through activation of nuclear receptors, such as the pregnane X receptor. However, this induction of CYP3A4 has not yet been investigated in humans. Thus, the aim of the study was to determine the variability of the CYP3......A4 phenotype in regard to increased concentrations of PCBs and other persistent organohalogen pollutants (POPs) in healthy Faroese adults. In 310 randomly selected Faroese residents aged 18-60 years, the CYP3A4 activity was determined based on the urinary 6beta-hydroxycortisol/cortisol (6beta...

Sex difference in induction of hepatic CYP2B and CYP3A subfamily enzymes by nicardipine and nifedipine in rats

International Nuclear Information System (INIS)

Konno, Yoshihiro; Sekimoto, Masashi; Nemoto, Kiyomitsu; Degawa, Masakuni

2004-01-01

Male and female of F344 rats were treated per os with nicardipine (Nic) and nifedipine (Nif), and changes in the levels of mRNA and protein of hepatic cytochrome P450 (P450) enzymes, CYP2B1, CYP2B2, CYP3A1, CYP3A2, CYP3A9, and CYP3A18 were examined. Furthermore, hepatic microsomal activities for pentoxyresorufin O-dealkylation (PROD) and nifedipine oxidation, which are mainly mediated by CYP2B and CYP3A subfamily enzymes, respectively, were measured. Analyses of RT-PCR and Western blotting revealed that Nic and Nif induced predominantly CYP3A and CYP2B enzymes, respectively. As for the gene activation of CYP2B enzymes, especially CYP2B1, Nif showed high capacity in both sexes of rats, whereas Nic did a definite capacity in the males but little in the females. Gene activations of CYP3A1, CYP3A2, and CYP3A18 by Nic occurred in both sexes of rats, although that of CYP3A9 did only in the male rats. Although gene activations of CYP3A1 and CYP3A2 by Nif were observed in both sexes of rats, a slight activation of the CYP3A9 gene occurred only in female rats, and the CYP3A18 gene activation, in neither male nor female rats. Thus, changes in levels of the mRNA or protein of CYP2B and CYP3A enzymes, especially CYP2B1 and CYP3A2, were closely correlated with those in hepatic PROD and nifedipine oxidation activities, respectively. The present findings demonstrate for the first time the sex difference in the Nic- and Nif-mediated induction of hepatic P450 enzymes in rats and further indicate that Nic and Nif show different specificities and sex dependencies in the induction of hepatic P450 enzymes

Induction of salt tolerance in Azolla microphylla Kaulf through modulation of antioxidant enzymes and ion transport.

Science.gov (United States)

Abraham, Gerard; Dhar, Dolly Wattal

2010-09-01

Azolla microphylla plants exposed directly to NaCl (13 dsm(-1)) did not survive the salinity treatment beyond a period of one day, whereas plants exposed directly to 4 and 9 dsm(-1) NaCl were able to grow and produce biomass. However, plants pre-exposed to NaCl (2 dsm(-1)) for 7 days on subsequent exposure to 13 dsm(-1) NaCl were able to grow and produce biomass although at a slow rate and are hereinafter designated as pre-exposed plants. The pre-exposed and directly exposed plants distinctly differed in their response to salt in terms of lipid peroxidation, proline accumulation, activity of antioxidant enzymes, such as SOD, APX, and CAT, and Na(+)/K(+) ratio. Efficient modulation of antioxidant enzymes coupled with regulation of ion transport play an important role in the induction of salt tolerance. Results show that it is possible to induce salt adaptation in A. microphylla by pre-exposing them to low concentrations of NaCl.

Oligogalacturonide-mediated induction of a gene involved in jasmonic acid synthesis in response to the cell-wall-degrading enzymes of the plant pathogen Erwinia carotovora.

Science.gov (United States)

Norman, C; Vidal, S; Palva, E T

1999-07-01

Identification of Arabidopsis thaliana genes responsive to plant cell-wall-degrading enzymes of Erwinia carotovora subsp. carotovora led to the isolation of a cDNA clone with high sequence homology to the gene for allene oxide synthase, an enzyme involved in the biosynthesis of jasmonates. Expression of the corresponding gene was induced by the extracellular enzymes from this pathogen as well as by treatment with methyl jasmonate and short oligogalacturonides (OGAs). This suggests that OGAs are involved in the induction of the jasmonate pathway during plant defense response to E. carotovora subsp. carotovora attack.

Dose of Phenobarbital and Age of Treatment at Early Life are Two Key Factors for the Persistent Induction of Cytochrome P450 Enzymes in Adult Mouse Liver.

Science.gov (United States)

Tien, Yun-Chen; Liu, Ke; Pope, Chad; Wang, Pengcheng; Ma, Xiaochao; Zhong, Xiao-bo

2015-12-01

Drug treatment of neonates and infants and its long-term consequences on drug responses have emerged in recent years as a major challenge for health care professionals. In the current study, we use phenobarbital as a model drug and mouse as an in vivo model to demonstrate that the dose of phenobarbital and age of treatment are two key factors for the persistent induction of gene expression and consequential increases of enzyme activities of Cyp2b, Cyp2c, and Cyp3a in adult livers. We show that phenobarbital treatment at early life of day 5 after birth with a low dose (phenobarbital treatment with a high dose (>200 mg/kg) significantly increases expression and enzyme activities of these P450s in adult liver. We also demonstrate that phenobarbital treatment before day 10 after birth, but not at later ages, significantly increases mRNAs, proteins, and enzyme activities of the tested P450s. Such persistent induction of P450 gene expression and enzyme activities in adult livers by phenobarbital treatment only occurs within a sensitive age window early in life. The persistent induction in gene expression and enzyme activities is higher in female mice than in male mice for Cyp2b10 but not for Cyp2c29 and Cyp3a11. These results will stimulate studies to evaluate the long-term impacts of drug treatment with different doses at neonatal and infant ages on drug metabolism, therapeutic efficacy, and drug-induced toxicity throughout the rest of life. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

Possible involvement of G-proteins and cAMP in the induction of progesterone hydroxylating enzyme system in the vascular wilt fungus Fusarium oxysporum.

Science.gov (United States)

Poli, Anna; Di Pietro, Antonio; Zigon, Dusan; Lenasi, Helena

2009-02-01

Fungi present the ability to hydroxylate steroids. In some filamentous fungi, progesterone induces an enzyme system which converts the compound into a less toxic hydroxylated product. We investigated the progesterone response in the vascular wilt pathogen Fusarium oxysporum, using mass spectrometry and high performance liquid chromatography (HPLC). Progesterone was mainly transformed into 15alpha-hydroxyprogesterone, which was found predominantly in the extracellular medium. The role of two conserved fungal signaling cascades in the induction of the progesterone-transforming enzyme system was studied, using knockout mutants lacking the mitogen-activated protein kinase Fmk1 or the heterotrimeric G-protein beta subunit Fgb1 functioning upstream of the cyclic adenosine monophosphate (cAMP) pathway. No steroid hydroxylation was induced in the Deltafgb1 strain, suggesting a role for the G-protein beta subunit in progesterone signaling. Exogenous cAMP restored the induction of progesterone-transforming activity in the Deltafgb1 strain, suggesting that steroid signaling in F. oxysporum is mediated by the cAMP-PKA pathway.

Cistanche tubulosa ethanol extract mediates rat sex hormone levels by induction of testicular steroidgenic enzymes.

Science.gov (United States)

Wang, Tian; Chen, Chen; Yang, Man; Deng, Baiwan; Kirby, Gordon Michael; Zhang, Xiaoying

2016-01-01

Plants of the genus Cistanche Hoffmg. et Link (Orobanchaceae) are usually used as ethno-medicine in Eastern Asia. Pharmacology studies have shown that Cistanche possesses an androgen-like effect; however, the exact mechanism is unclear. The present study determines the effect of ethanol extract of Cistanche tubulosa (Schenk) R. Wight stem (CTE) on hormone levels and testicular steroidogenic enzymes in rats. Phenylethanoid glycoside content of CTE was detected by UV spectrophotometry. Rats were fed with different doses of CTE (0.2, 0.4, and 0.8 g/kg) by intragastric administration for 20 d. Sperm parameters were measured by staining and counting method. The level of progesterone and testosterone in serum was quantified by radioimmunoassay. The expression levels of cholesterol side-chain cleavage enzyme (CYP11A1), 17α-hydroxylase/17, 20-lyase (CYP17A1), and a liver metabolic enzyme (CYP3A4) in the microsome were assessed by immunohistochemical staining or/and western blot analysis. The study illustrates that the administration of CTE (0.4 and 0.8 g/kg) increased sperm count (2.3- and 2.7-folds) and sperm motility (1.3- and 1.4-folds) and decreased the abnormal sperm (0.76- and 0.6-folds). The serum level of progesterone and testosterone in rats was also increased by CTE administration (p blot analysis confirmed that the expression of CYP11A1, CYP17A1, and CYP3A4 was enhanced by CTE (p < 0.05). It was also found that high-dose of CTE can cause mild hepatic edema. Our results suggest that the increase in sex hormone levels could be mediated by the induction of testicular steroidogenic enzymes.

The effect of esmolol on corrected-QT interval, corrected-QT interval dispersion changes seen during anesthesia induction in hypertensive patients taking an angiotensin-converting enzyme inhibitor

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Zahit Çeker

2015-02-01

Full Text Available BACKGROUND AND OBJECTIVES: The importance of minimizing the exaggerated sympatho-adrenergic responses and QT interval and QT interval dispersion changes that may develop due to laryngoscopy and tracheal intubation during anesthesia induction in the hypertensive patients is clear. Esmolol decreases the hemodynamic response to laryngoscopy and intubation. However, the effect of esmolol in decreasing the prolonged QT interval and QT interval dispersion as induced by laryngoscopy and intubation is controversial. We investigated the effect of esmolol on the hemodynamic, and corrected-QT interval and corrected-QT interval dispersion changes seen during anesthesia induction in hypertensive patients using angiotensin converting enzyme inhibitors. METHODS: 60 ASA I-II patients, with essential hypertension using angiotensin converting enzyme inhibitors were included in the study. The esmolol group received esmolol at a bolus dose of 500 mcg/kg followed by a 100 mcg/kg/min infusion which continued until the 4th min after intubation. The control group received 0.9% saline similar to the esmolol group. The mean blood pressure, heart rate values and the electrocardiogram records were obtained as baseline values before the anesthesia, 5 min after esmolol and saline administration, 3 min after the induction and 30 s, 2 min and 4 min after intubation. RESULTS: The corrected-QT interval was shorter in the esmolol group (p = 0.012, the corrected-QT interval dispersion interval was longer in the control group (p = 0.034 and the mean heart rate was higher in the control group (p = 0.022 30 s after intubation. The risk of arrhythmia frequency was higher in the control group in the 4-min period following intubation (p = 0.038. CONCLUSION: Endotracheal intubation was found to prolong corrected-QT interval and corrected-QT interval dispersion, and increase the heart rate during anesthesia induction with propofol in hypertensive patients using angiotensin converting

Effects of atorvastatin metabolites on induction of drug-metabolizing enzymes and membrane transporters through human pregnane X receptor

Science.gov (United States)

Hoffart, E; Ghebreghiorghis, L; Nussler, AK; Thasler, WE; Weiss, TS; Schwab, M; Burk, O

2012-01-01

BACKGROUND AND PURPOSE Atorvastatin metabolites differ in their potential for drug interaction because of differential inhibition of drug-metabolizing enzymes and transporters. We here investigate whether they exert differential effects on the induction of these genes via activation of pregnane X receptor (PXR) and constitutive androstane receptor (CAR). EXPERIMENTAL APPROACH Ligand binding to PXR or CAR was analysed by mammalian two-hybrid assembly and promoter/reporter gene assays. Additionally, surface plasmon resonance was used to analyse ligand binding to CAR. Primary human hepatocytes were treated with atorvastatin metabolites, and mRNA and protein expression of PXR-regulated genes was measured. Two-hybrid co-activator interaction and co-repressor release assays were utilized to elucidate the molecular mechanism of PXR activation. KEY RESULTS All atorvastatin metabolites induced the assembly of PXR and activated CYP3A4 promoter activity. Ligand binding to CAR could not be proven. In primary human hepatocytes, the para-hydroxy metabolite markedly reduced or abolished induction of cytochrome P450 and transporter genes. While significant differences in co-activator recruitment were not observed, para-hydroxy atorvastatin demonstrated only 50% release of co-repressors. CONCLUSIONS AND IMPLICATIONS Atorvastatin metabolites are ligands of PXR but not of CAR. Atorvastatin metabolites demonstrate differential induction of PXR target genes, which results from impaired release of co-repressors. Consequently, the properties of drug metabolites have to be taken into account when analysing PXR-dependent induction of drug metabolism and transport. The drug interaction potential of the active metabolite, para-hydroxy atorvastatin, might be lower than that of the parent compound. PMID:21913896

[The effect of esmolol on corrected-QT interval, corrected-QT interval dispersion changes seen during anesthesia induction in hypertensive patients taking an angiotensin-converting enzyme inhibitor].

Science.gov (United States)

Ceker, Zahit; Takmaz, Suna Akın; Baltaci, Bülent; Başar, Hülya

2015-01-01

The importance of minimizing the exaggerated sympatho-adrenergic responses and QT interval and QT interval dispersion changes that may develop due to laryngoscopy and tracheal intubation during anesthesia induction in the hypertensive patients is clear. Esmolol decreases the hemodynamic response to laryngoscopy and intubation. However, the effect of esmolol in decreasing the prolonged QT interval and QT interval dispersion as induced by laryngoscopy and intubation is controversial. We investigated the effect of esmolol on the hemodynamic, and corrected-QT interval and corrected-QT interval dispersion changes seen during anesthesia induction in hypertensive patients using angiotensin converting enzyme inhibitors. 60 ASA I-II patients, with essential hypertension using angiotensin converting enzyme inhibitors were included in the study. The esmolol group received esmolol at a bolus dose of 500mcg/kg followed by a 100mcg/kg/min infusion which continued until the 4th min after intubation. The control group received 0.9% saline similar to the esmolol group. The mean blood pressure, heart rate values and the electrocardiogram records were obtained as baseline values before the anesthesia, 5min after esmolol and saline administration, 3min after the induction and 30s, 2min and 4min after intubation. The corrected-QT interval was shorter in the esmolol group (p=0.012), the corrected-QT interval dispersion interval was longer in the control group (p=0.034) and the mean heart rate was higher in the control group (p=0.022) 30s after intubation. The risk of arrhythmia frequency was higher in the control group in the 4-min period following intubation (p=0.038). Endotracheal intubation was found to prolong corrected-QT interval and corrected-QT interval dispersion, and increase the heart rate during anesthesia induction with propofol in hypertensive patients using angiotensin converting enzyme inhibitors. These effects were prevented with esmolol (500mcg/kg bolus, followed by

Developing Potential Candidates of Preclinical Preeclampsia

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Sandra Founds

2015-11-01

Full Text Available The potential for developing molecules of interest in preclinical preeclampsia from candidate genes that were discovered on gene expression microarray analysis has been challenged by limited access to additional first trimester trophoblast and decidual tissues. The question of whether these candidates encode secreted proteins that may be detected in maternal circulation early in pregnancy has been investigated using various proteomic methods. Pilot studies utilizing mass spectrometry based proteomic assays, along with enzyme linked immunosorbent assays (ELISAs, and Western immunoblotting in first trimester samples are reported. The novel targeted mass spectrometry methods led to robust multiple reaction monitoring assays. Despite detection of several candidates in early gestation, challenges persist. Future antibody-based studies may lead to a novel multiplex protein panel for screening or detection to prevent or mitigate preeclampsia.

Dipeptidyl peptidase IV is involved in the cellulose-responsive induction of cellulose biomass-degrading enzyme genes in Aspergillus aculeatus.

Science.gov (United States)

Tani, Shuji; Yuki, Shota; Kunitake, Emi; Sumitani, Jun-Ichi; Kawaguchi, Takashi

2017-06-01

We screened for factors involved in the cellulose-responsive induction of cellulose biomass-degrading enzyme genes from approximately 12,000 Aspergillus aculeatus T-DNA insertion mutants harboring a transcriptional fusion between the FIII-avicelase gene (cbhI) promoter and the orotidine 5'-monophosphate decarboxylase gene. Analysis of 5-fluoroorodic acid (5-FOA) sensitivity, cellulose utilization, and cbhI expression of the mutants revealed that a mutant harboring T-DNA at the dipeptidyl peptidase IV (dppIV) locus had acquired 5-FOA resistance and was deficient in cellulose utilization and cbhI expression. The deletion of dppIV resulted in a significant reduction in the cellulose-responsive expression of both cbhI as well as genes controlled by XlnR-independent and XlnR-dependent signaling pathways at an early phase in A. aculeatus. In contrast, the dppIV deletion did not affect the xylose-responsive expression of genes under the control of XlnR. These results demonstrate that DppIV participates in cellulose-responsive induction in A. aculeatus.

Polyphenol Oxidase Induction in Lulo Fruits (Solanum quitoense Infected by Colletotrichum acutatum

Directory of Open Access Journals (Sweden)

Obradith Caicedo O.

2007-08-01

Full Text Available Polyphenol oxidase (PFO activity induction was evaluated in lulo fruits to determine the role of this enzyme in resistance responses towards the pathogen Colletotrichum acutatum which causes anthracnose disease. We studied the experimental conditions to obtain the enzyme, using lulo peel, and found that extraction with phosphates buffer 100 mM pH 7, 1% SDS y 1% PVPP showed higher activities. The adequate parameters for activity measurement was also evaluated and established as cathecol 40 mM, pH 7,0, 23 °C and 30 µL of extract. Then, we performed an in vivo assay using lulo fruits in three maturity stages, green, semimature and mature, which were inoculated with the fungus or with sterile water. Enzymatic induction of this protein was studied at nine postinoculation times, and it was found that the induction was differential according to the time, the maturity stage, and as consequence of pathogen presence. The PFO activity increased in green fruits at 48, 96 y 144 (hours postinoculation (hpi, and in mature lulos for the majority of times studied, with the most significant induction response at this stage. In semimature lulo, the induction was observed only at 72 and 144 hpi. The highest nominal value of activity was found in green fruits. Fruits responded to incision with enzyme activation. The increase in the activity of the enzyme was faster in the fruits with the minor anthracnose symptoms than the ones that were more affected. Therefore, it is possible to postulate a positive relation between PFO induction and tolerance to anthracnose symptoms.

Polychlorinated biphenyl (PCB) induction of CYP3A4 enzyme activity in healthy Faroese adults

International Nuclear Information System (INIS)

Petersen, Maria Skaalum; Halling, Jonrit; Damkier, Per; Nielsen, Flemming; Grandjean, Philippe; Weihe, Pal; Brosen, Kim

2007-01-01

The CYP3A4 enzyme is, along with other cytochrome P450 enzymes, involved in the metabolism of environmental pollutants and is highly inducible by these substances. A commercial polychlorinated biphenyl (PCB) mixture, 1,1,1,-trichloro-2-(o-chlorophenyl), 2-(p'-chlorophenyl)ethane (o,p'-DDT) and 1,1,-dichloro-2,2-bis (p-chlorophenyl)ethene (p,p'-DDE) are known to induce CYP3A4 activity through activation of nuclear receptors, such as the pregnane X receptor. However, this induction of CYP3A4 has not yet been investigated in humans. Thus, the aim of the study was to determine the variability of the CYP3A4 phenotype in regard to increased concentrations of PCBs and other persistent organohalogen pollutants (POPs) in healthy Faroese adults. In 310 randomly selected Faroese residents aged 18-60 years, the CYP3A4 activity was determined based on the urinary 6β-hydroxycortisol/cortisol (6β-OHC/FC) ratio. POP exposures were assessed by measuring their concentrations in serum lipid. The results showed a unimodal distribution of the 6β-OHC/FC ratio with values ranging from 0.58 to 27.38. Women had a slightly higher 6β-OHC/FC ratio than men (p = 0.07). Confounder-adjusted multiple regression analysis showed significant associations between 6β-OHC/FC ratios and ΣPCB, PCB-TEQ and p,p'-DDE, o,p'-DDT and HCB, respectively, but the associations were statistically significant for men only

Regorafenib: Antitumor Activity upon Mono and Combination Therapy in Preclinical Pediatric Malignancy Models.

Science.gov (United States)

Daudigeos-Dubus, Estelle; Le Dret, Ludivine; Lanvers-Kaminsky, Claudia; Bawa, Olivia; Opolon, Paule; Vievard, Albane; Villa, Irène; Pagès, Mélanie; Bosq, Jacques; Vassal, Gilles; Zopf, Dieter; Geoerger, Birgit

2015-01-01

The multikinase inhibitor regorafenib (BAY 73-4506) exerts both anti-angiogenic and anti-tumorigenic activity in adult solid malignancies mainly advanced colorectal cancer and gastrointestinal stromal tumors. We intended to explore preclinically the potential of regorafenib against solid pediatric malignancies alone and in combination with anticancer agents to guide the pediatric development plan. In vitro effects on cell proliferation were screened against 33 solid tumor cell lines of the Innovative Therapies for Children with Cancer (ITCC) panel covering five pediatric solid malignancies. Regorafenib inhibited cell proliferation with a mean half maximal growth inhibition of 12.5 μmol/L (range 0.7 μmol/L to 28 μmol/L). In vivo, regorafenib was evaluated alone at 10 or 30 mg/kg/d or in combination with radiation, irinotecan or the mitogen-activated protein kinase kinase (MEK) inhibitor refametinib against various tumor types, including patient-derived brain tumor models with an amplified platelet-derived growth factor receptor A (PDGFRA) gene. Regorafenib alone significantly inhibited tumor growth in all xenografts derived from nervous system and connective tissue tumors. Enhanced effects were observed when regorafenib was combined with irradiation and irinotecan against PDGFRA amplified IGRG93 glioma and IGRM57 medulloblastoma respectively, resulting in 100% tumor regressions. Antitumor activity was associated with decreased tumor vascularization, inhibition of PDGFR signaling, and induction of apoptotic cell death. Our work demonstrates that regorafenib exhibits significant antitumor activity in a wide spectrum of preclinical pediatric models through inhibition of angiogenesis and induction of apoptosis. Furthermore, radio- and chemosensitizing effects were observed with DNA damaging agents in PDGFR amplified tumors.

Mathematical modelling of enzyme synthesis during fermentations: the Q-functions

Energy Technology Data Exchange (ETDEWEB)

Nielsen, H K; Martiny, S C

1981-01-01

In modeling enzyme synthesis, the Q-function has been generalized to describe ordinary induction and repression as well as mixed induction-repression. The practical use of the Q-function as found in the literature was considered, especially the implications of applying fractional exponents.

Induction, purification and characterisation of arabinases produced by Aspergillus niger.

NARCIS (Netherlands)

Veen, van de P.; Flipphi, M.J.A.; Voragen, A.G.J.; Visser, J.

1991-01-01

The induction of arabinases in Aspergillus niger N400 was studied on different simple and complex carbon sources. Sugar beet pulp was found to be an inducer of three arabinan degrading enzymes (alpha-L-arabinofuranosidase A, alpha-L-arabinofuranosidase B and endoarabinase). These enzymes were

Towards the pre-clinical diagnosis of hypothyroidism caused by iodotyrosine deiodinase (DEHAL1) defects.

Science.gov (United States)

Iglesias, Ainhoa; García-Nimo, Laura; Cocho de Juan, José A; Moreno, José C

2014-03-01

DEHAL1 (also named IYD) is the thyroidal enzyme that deiodinates mono- and diiodotyrosines (MIT, DIT) and recycles iodine, a scarce element in the environment, for the efficient synthesis of thyroid hormone. Failure of this enzyme leads to the iodotyrosine deiodinase deficiency (ITDD), characterized by hypothyroidism, compressive goiter and variable mental retardation, whose diagnostic hallmark is the elevation of iodotyrosines in serum and urine. However, the specific diagnosis of this type of hypothyroidism is not routinely performed, due to technical and practical difficulties in iodotyrosine determinations. A handful of mutations in the DEHAL1 gene have been identified as the molecular basis for the ITDD. Patients harboring DEHAL1 defects so far described all belong to consanguineous families, and psychomotor deficits were present in some affected individuals. This is probably due to the lack of biochemical expression of the disease at the beginning of life, which causes ITDD being undetected in screening programs for congenital hypothyroidism, as currently performed. This worrying feature calls for efforts to improve pre-clinical detection of iodotyrosine deiodinase deficiency during the neonatal time. Such a challenge poses questions of patho-physiological (natural history of the disease, environmental factors influencing its expression) epidemiological (prevalence of ITDD) and technical nature (development of optimal methodology for safe detection of pre-clinical ITDD), which will be addressed in this review. Copyright © 2013 Elsevier Ltd. All rights reserved.

Induction of cellular and molecular immunomodulatory pathways by vitamin A and Flavonoids

Science.gov (United States)

Patel, Sapna; Vajdy, Michael

2016-01-01

Introduction A detailed study of reports on the immunomodulatory properties of vitamin A and select flavonoids may pave the way for using these natural compounds or compounds with similar structures in novel drug and vaccine designs against infectious and autoimmune diseases and cancers. Areas Covered Intracellular transduction pathways, cellular differentiation and functional immunomodulatory responses have been reviewed. The reported studies encompass in vitro, in vivo preclinical and clinical studies that address the role of Vitamin A and select flavonoids in induction of innate and adaptive B and T cell responses, including TH1, TH2 and Treg. Expert Opinion While the immunomodulatory role of vitamin A, and related compounds, is well-established in many preclinical studies, its role in humans has begun to gain wider acceptance. In contrast, the role of flavonoids is mostly controversial in clinical trials, due to the diversity of the various classes of these compounds, and possibly due to the purity and the selected doses of the compounds. However, current preclinical and clinical studies warrant further detailed studies of these promising immuno-modulatory compounds. PMID:26185959

The 14C-monomethylamino-antipyrine breath test as in vivo parameter for characterizing the induction of the drug catabolizing enzyme system in the guinea pig

International Nuclear Information System (INIS)

Gramatzki, S.

1981-01-01

The aim of these investigations was to help clarify the following questions: 1) Does MAAP, following 14 C labelling of the exocyclic aminomethyl group, offer a suitable substrate for a breath test in guinea pigs. 2) Which procedures for evaluating the 14 C exhalation curves of the breath test are especially valid. 3) Can an induction of the drug catabolizing enzyme system following pre-treatment with various inducing substances be detected by the 14 C-MAAP breath test. 4) Do inducer-specific differences arise in response to the 14 C-MAAP breath test by which the inducers can be characterized. 5) Is monomethylamino-antipyrine similar to amidopyrine in that it is a suitable independent in vivo parameter for the drug metasbolizing enzyme system in the liver of guinea pigs. (orig./MG) [de

Induction of the Histamine-Forming Enzyme Histidine Decarboxylase in Skeletal Muscles by Prolonged Muscular Work: Histological Demonstration and Mediation by Cytokines.

Science.gov (United States)

Ayada, Kentaro; Tsuchiya, Masahiro; Yoneda, Hiroyuki; Yamaguchi, Kouji; Kumamoto, Hiroyuki; Sasaki, Keiichi; Tadano, Takeshi; Watanabe, Makoto; Endo, Yasuo

2017-01-01

Recent studies suggest that histamine-a regulator of the microcirculation-may play important roles in exercise. We have shown that the histamine-forming enzyme histidine decarboxylase (HDC) is induced in skeletal muscles by prolonged muscular work (PMW). However, histological analysis of such HDC induction is lacking due to appropriate anti-HDC antibodies being unavailable. We also showed that the inflammatory cytokines interleukin (IL)-1 and tumor necrosis factor (TNF)-α can induce HDC, and that PMW increases both IL-1α and IL-1β in skeletal muscles. Here, we examined the effects (a) of PMW on the histological evidence of HDC induction and (b) of IL-1β and TNF-α on HDC activity in skeletal muscles. By immunostaining using a recently introduced commercial polyclonal anti-HDC antibody, we found that cells in the endomysium and around blood vessels, and also some muscle fibers themselves, became HDC-positive after PMW. After PMW, TNF-α, but not IL-1α or IL-1β, was detected in the blood serum. The minimum intravenous dose of IL-1β that would induce HDC activity was about 1/10 that of TNF-α, while in combination they synergistically augmented HDC activity. These results suggest that PMW induces HDC in skeletal muscles, including cells in the endomysium and around blood vessels, and also some muscle fibers themselves, and that IL-1β and TNF-α may cooperatively mediate this induction.

Regorafenib: Antitumor Activity upon Mono and Combination Therapy in Preclinical Pediatric Malignancy Models.

Directory of Open Access Journals (Sweden)

Estelle Daudigeos-Dubus

Full Text Available The multikinase inhibitor regorafenib (BAY 73-4506 exerts both anti-angiogenic and anti-tumorigenic activity in adult solid malignancies mainly advanced colorectal cancer and gastrointestinal stromal tumors. We intended to explore preclinically the potential of regorafenib against solid pediatric malignancies alone and in combination with anticancer agents to guide the pediatric development plan. In vitro effects on cell proliferation were screened against 33 solid tumor cell lines of the Innovative Therapies for Children with Cancer (ITCC panel covering five pediatric solid malignancies. Regorafenib inhibited cell proliferation with a mean half maximal growth inhibition of 12.5 μmol/L (range 0.7 μmol/L to 28 μmol/L. In vivo, regorafenib was evaluated alone at 10 or 30 mg/kg/d or in combination with radiation, irinotecan or the mitogen-activated protein kinase kinase (MEK inhibitor refametinib against various tumor types, including patient-derived brain tumor models with an amplified platelet-derived growth factor receptor A (PDGFRA gene. Regorafenib alone significantly inhibited tumor growth in all xenografts derived from nervous system and connective tissue tumors. Enhanced effects were observed when regorafenib was combined with irradiation and irinotecan against PDGFRA amplified IGRG93 glioma and IGRM57 medulloblastoma respectively, resulting in 100% tumor regressions. Antitumor activity was associated with decreased tumor vascularization, inhibition of PDGFR signaling, and induction of apoptotic cell death. Our work demonstrates that regorafenib exhibits significant antitumor activity in a wide spectrum of preclinical pediatric models through inhibition of angiogenesis and induction of apoptosis. Furthermore, radio- and chemosensitizing effects were observed with DNA damaging agents in PDGFR amplified tumors.

Modulation of porcine biotransformation enzymes by anthelmintic therapy with fenbendazole and flubendazole.

Science.gov (United States)

Savlík, M; Fimanová, K; Szotáková, B; Lamka, J; Skálová, L

2006-06-01

Fenbendazole (FEN) and flubendazole (FLU) are benzimidazole anthelmintics often used in pig management for the control of nematodoses. The in vivo study presented here was designed to test the influence of FLU and FEN on cytochrome P4501A and other cytochrome P450 (CYP) isoforms, UDP-glucuronosyl transferase and several carbonyl reducing enzymes. The results indicated that FEN (in a single therapeutic dose as well as in repeated therapeutic doses) caused significant induction of pig CYP1A, while FLU did not show an inductive effect towards this isoform. Some of the other hepatic and intestinal biotransformation enzymes that were assayed were moderately influenced by FEN or FLU. Strong CYP1A induction following FEN therapy in pigs may negatively affect the efficacy and pharmacokinetics of FEN itself or other simultaneously or consecutively administered drugs. From the perspective of biotransformation enzyme modulation, FLU would appear to be a more convenient anthelmintic therapy of pigs than FEN.

Extending the theoretical framework for curriculum integration in pre-clinical medical education

DEFF Research Database (Denmark)

Vergel, John; Stentoft, Diana; Montoya, Juny

2017-01-01

students' knowledge integration. Therefore, we aimed to uncover how curriculum integration is manifested through context. METHODS: We collected data from the official curriculum and interviewed ten participants (including curriculum designers, facilitators, and students) in the bachelor's medical program......INTRODUCTION: Curriculum integration is widely discussed in medical education but remains ill defined. Although there is plenty of information on logistical aspects of curriculum integration, little attention has been paid to the contextual issues that emerge from its practice and may complicate...... at Aalborg University. We observed various learning activities focused on pre-clinical education. Inspired by grounded theory, we analyzed the information we gathered. RESULTS: The following theoretical constructs emerged after the inductive analysis: 1) curriculum integration complexity is embedded...

Catabolite repression and nitrogen control of allantoin-degrading enzymes in Pseudomonas aeruginosa

NARCIS (Netherlands)

Janssen, D.B.; Drift, C. van der

1983-01-01

The formation of the allantoin-degrading enzymes allantoinase, allantoicase and ureidoglycolase in Pseudomonas aeruginosa was found to be regulated by induction, catabolite repression and nitrogen control. Induction was observed when urate, allantoin or allantoate were included in the growth medium,

INDUCTION OF AUTOANTIBODIES TO HUMAN ENZYMES FOLLOWING VIRAL-INFECTION - A BIOLOGICALLY RELEVANT HYPOTHESIS

NARCIS (Netherlands)

WEIJERS, RNM; LAWSON, C; LEUNISSEN, J

Macro enzymes, i. e. complexes of normal (iso-)enzymes with an immunoglobulin, may be due to immunological cross-reactions evoked by specific viral antigenic determinants that are homologous to regions in the target enzymes. A search of the National Biomedical Research Foundation protein databank

effect of caffeine -coconut products interactions on induction of ...

African Journals Online (AJOL)

INDUCTION OF MICROSOMAL DRUG-METABOLIZING ENZYMES IN ... examine several biochemical parameters, ie, total protein and RNA levels, ... Caffeine also acts to increase alertness, ... Mechanisms of action of caffeine involve.

The induction of two biosynthetic enzymes helps Escherichia coli sustain heme synthesis and activate catalase during hydrogen peroxide stress.

Science.gov (United States)

Mancini, Stefano; Imlay, James A

2015-05-01

Hydrogen peroxide pervades many natural environments, including the phagosomes that mediate cell-based immunity. Transcriptomic analysis showed that during protracted low-grade H(2)O(2) stress, Escherichia coli responds by activating both the OxyR defensive regulon and the Fur iron-starvation response. OxyR induced synthesis of two members of the nine-step heme biosynthetic pathway: ferrochelatase (HemH) and an isozyme of coproporphyrinogen III oxidase (HemF). Mutations that blocked either adaptation caused the accumulation of porphyrin intermediates, inadequate activation of heme enzymes, low catalase activity, defective clearance of H(2)O(2) and a failure to grow. Genetic analysis indicated that HemH induction is needed to compensate for iron sequestration by the mini-ferritin Dps. Dps activity protects DNA and proteins by limiting Fenton chemistry, but it interferes with the ability of HemH to acquire the iron that it needs to complete heme synthesis. HemF is a manganoprotein that displaces HemN, an iron-sulfur enzyme whose synthesis and/or stability is apparently problematic during H(2)O(2) stress. Thus, the primary responses to H(2)O(2), including the sequestration of iron, require compensatory adjustments in the mechanisms of iron-cofactor synthesis. The results support the growing evidence that oxidative stress is primarily an iron pathology. © 2015 John Wiley & Sons Ltd.

Arabinase induction and carbon catabolite repression in Aspergillus niger and Aspergillus nidulans

NARCIS (Netherlands)

Veen, van der P.

1995-01-01

The first aim of this thesis was to get a better understanding of the properties and the induction features of arabinan degrading enzymes and enzymes involved in the intracellular L-arabinose catabolic pathway in Aspergillus niger. The second aim was to understand the

Involvement of methyltransferases enzymes during the energy ...

African Journals Online (AJOL)

The methyl group transfer from dimethylsulfide (DMS), trimethylamine and methanol to 2-mercaptoethanesulfonic acid (coenzyme M) were investigated from cell extracts of Methanosarcina semesiae sp. nov. to evaluate whether the enzyme systems involved were constitutive or inductive. The extracts from cells grown on ...

Shotgun proteomics of Aspergillus niger microsomes upon D-xylose induction.

Science.gov (United States)

Ferreira de Oliveira, José Miguel P; van Passel, Mark W J; Schaap, Peter J; de Graaff, Leo H

2010-07-01

Protein secretion plays an eminent role in cell maintenance and adaptation to the extracellular environment of microorganisms. Although protein secretion is an extremely efficient process in filamentous fungi, the mechanisms underlying protein secretion have remained largely uncharacterized in these organisms. In this study, we analyzed the effects of the d-xylose induction of cellulase and hemicellulase enzyme secretion on the protein composition of secretory organelles in Aspergillus niger. We aimed to systematically identify the components involved in the secretion of these enzymes via mass spectrometry of enriched subcellular microsomal fractions. Under each condition, fractions enriched for secretory organelles were processed for tandem mass spectrometry, resulting in the identification of peptides that originate from 1,081 proteins, 254 of which-many of them hypothetical proteins-were predicted to play direct roles in the secretory pathway. d-Xylose induction led to an increase in specific small GTPases known to be associated with polarized growth, exocytosis, and endocytosis. Moreover, the endoplasmic-reticulum-associated degradation (ERAD) components Cdc48 and all 14 of the 20S proteasomal subunits were recruited to the secretory organelles. In conclusion, induction of extracellular enzymes results in specific changes in the secretory subproteome of A. niger, and the most prominent change found in this study was the recruitment of the 20S proteasomal subunits to the secretory organelles.

Preclinical models in radiation oncology

Directory of Open Access Journals (Sweden)

Kahn Jenna

2012-12-01

Full Text Available Abstract As the incidence of cancer continues to rise, the use of radiotherapy has emerged as a leading treatment modality. Preclinical models in radiation oncology are essential tools for cancer research and therapeutics. Various model systems have been used to test radiation therapy, including in vitro cell culture assays as well as in vivo ectopic and orthotopic xenograft models. This review aims to describe such models, their advantages and disadvantages, particularly as they have been employed in the discovery of molecular targets for tumor radiosensitization. Ultimately, any model system must be judged by its utility in developing more effective cancer therapies, which is in turn dependent on its ability to simulate the biology of tumors as they exist in situ. Although every model has its limitations, each has played a significant role in preclinical testing. Continued advances in preclinical models will allow for the identification and application of targets for radiation in the clinic.

Induction of Laccase, Lignin Peroxidase and Manganese Peroxidase Activities in White-Rot Fungi Using Copper Complexes

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Martina Vrsanska

2016-11-01

Full Text Available Ligninolytic enzymes, such as laccase, lignin peroxidase and manganese peroxidase, are biotechnologically-important enzymes. The ability of five white-rot fungal strains Daedaleopsis confragosa, Fomes fomentarius, Trametes gibbosa, Trametes suaveolens and Trametes versicolor to produce these enzymes has been studied. Three different copper(II complexes have been prepared ((Him[Cu(im4(H2O2](btc·3H2O, where im = imidazole, H3btc = 1,3,5-benzenetricarboxylic acid, [Cu3(pmdien3(btc](ClO43·6H2O and [Cu3(mdpta3(btc](ClO43·4H2O, where pmdien = N,N,N′,N′′,N′′-pentamethyl-diethylenetriamine and mdpta = N,N-bis-(3-aminopropylmethyl- amine, and their potential application for laccase and peroxidases induction have been tested. The enzyme-inducing activities of the complexes were compared with that of copper sulfate, and it has been found that all of the complexes are suitable for the induction of laccase and peroxidase activities in white-rot fungi; however, the newly-synthesized complex M1 showed the greatest potential for the induction. With respect to the different copper inducers, this parameter seems to be important for enzyme activity, which depends also on the fungal strains.

Cloning and nitrate induction of nitrate reductase mRNA

OpenAIRE

Cheng, Chi-Lien; Dewdney, Julia; Kleinhofs, Andris; Goodman, Howard M.

1986-01-01

Nitrate is the major source of nitrogen taken from the soil by higher plants but requires reduction to ammonia prior to incorporation into amino acids. The first enzyme in the reducing pathway is a nitrate-inducible enzyme, nitrate reductase (EC 1.6.6.1). A specific polyclonal antiserum raised against purified barley nitrate reductase has been used to immunoprecipitate in vivo labeled protein and in vitro translation products, demonstrating that nitrate induction increases nitrate reductase p...

Recommendations for Benchmarking Preclinical Studies of Nanomedicines.

Science.gov (United States)

Dawidczyk, Charlene M; Russell, Luisa M; Searson, Peter C

2015-10-01

Nanoparticle-based delivery systems provide new opportunities to overcome the limitations associated with traditional small-molecule drug therapy for cancer and to achieve both therapeutic and diagnostic functions in the same platform. Preclinical trials are generally designed to assess therapeutic potential and not to optimize the design of the delivery platform. Consequently, progress in developing design rules for cancer nanomedicines has been slow, hindering progress in the field. Despite the large number of preclinical trials, several factors restrict comparison and benchmarking of different platforms, including variability in experimental design, reporting of results, and the lack of quantitative data. To solve this problem, we review the variables involved in the design of preclinical trials and propose a protocol for benchmarking that we recommend be included in in vivo preclinical studies of drug-delivery platforms for cancer therapy. This strategy will contribute to building the scientific knowledge base that enables development of design rules and accelerates the translation of new technologies. ©2015 American Association for Cancer Research.

Challenges for Preclinical Investigations of Human Biofield Modalities

Science.gov (United States)

Gronowicz, Gloria; Bengston, William

2015-01-01

Preclinical models for studying the effects of the human biofield have great potential to advance our understanding of human biofield modalities, which include external qigong, Johrei, Reiki, therapeutic touch, healing touch, polarity therapy, pranic healing, and other practices. A short history of Western biofield studies using preclinical models is presented and demonstrates numerous and consistent examples of human biofields significantly affecting biological systems both in vitro and in vivo. Methodological issues arising from these studies and practical solutions in experimental design are presented. Important questions still left unanswered with preclinical models include variable reproducibility, dosing, intentionality of the practitioner, best preclinical systems, and mechanisms. Input from the biofield practitioners in the experimental design is critical to improving experimental outcomes; however, the development of standard criteria for uniformity of practice and for inclusion of multiple practitioners is needed. Research in human biofield studies involving preclinical models promises a better understanding of the mechanisms underlying the efficacy of biofield therapies and will be important in guiding clinical protocols and integrating treatments with conventional medical therapies. PMID:26665042

Induction of Shikimic Acid Pathway Enzymes by Light in Suspension Cultured Cells of Parsley (Petroselinum crispum) 1

Science.gov (United States)

McCue, Kent F.; Conn, Eric E.

1990-01-01

Light treatment of suspension cultured cells of parsley (Petroselinum crispum) was shown to increase the activity of the shikimic acid pathway enzyme, 3-deoxy-d-arabino-heptulosonic acid-7-phosphate (DAHP) synthase (EC 4.1.2.15). DAHP synthase activity was assayed for two isoforms, DS-Mn and DS-Co (RJ Ganson, TA d'Amato, RA Jensen [1986] Plant Physiol 82: 203-210). Light increased the enzymatic activity of the plastidic isoform DS-Mn as much as 2-fold, averaging 1.6-fold with >95% confidence. The cytosolic isoform DS-Co was unaffected. Cycloheximide and actinomycin D, translational and transcriptional inhibitors, respectively, both reversed induction of DS-Mn by light suggesting transcriptional regulation of the gene. Chorismate mutase activity was assayed for the two isoforms CM I and CM II (BK Singh, JA Connelly, EE Conn [1985] Arch Biochem Biophys 243: 374-384). Treatment by light did not significantly affect either chorismate mutase isoform. The ratio of the two chorismate mutase isoforms changed during the growth cycle, with an increase in the ratio of plastidic to cytosolic isoforms occurring towards the end of logarithmic growth. PMID:16667741

Oxidative stress and the antioxidant enzyme system in the developing brain

Directory of Open Access Journals (Sweden)

So-Yeon Shim

2013-03-01

Full Text Available Preterm infants are vulnerable to the oxidative stress due to the production of large amounts of free radicals, antioxidant system insufficiency, and immature oligodendroglial cells. Reactive oxygen species (ROS play a pivotal role in the development of periventricular leukomalacia. The three most common ROS are superoxide (O2&#8226;-, hydroxyl radical (OH&#8226;, and hydrogen peroxide (H2O2. Under normal physiological conditions, a balance is maintained between the production of ROS and the capacity of the antioxidant enzyme system. However, if this balance breaks down, ROS can exert toxic effects. Superoxide dismutase, glutathione peroxidase, and catalase are considered the classical antioxidant enzymes. A recently discovered antioxidant enzyme family, peroxiredoxin (Prdx, is also an important scavenger of free radicals. Prdx1 expression is induced at birth, whereas Prdx2 is constitutively expressed, and Prdx6 expression is consistent with the classical antioxidant enzymes. Several antioxidant substances have been studied as potential therapeutic agents; however, further preclinical and clinical studies are required before allowing clinical application.

A High-Throughput (HTS) Assay for Enzyme Reaction Phenotyping in Human Recombinant P450 Enzymes Using LC-MS/MS.

Science.gov (United States)

Li, Xiaofeng; Suhar, Tom; Glass, Lateca; Rajaraman, Ganesh

2014-03-03

Enzyme reaction phenotyping is employed extensively during the early stages of drug discovery to identify the enzymes responsible for the metabolism of new chemical entities (NCEs). Early identification of metabolic pathways facilitates prediction of potential drug-drug interactions associated with enzyme polymorphism, induction, or inhibition, and aids in the design of clinical trials. Incubation of NCEs with human recombinant enzymes is a popular method for such work because of the specificity, simplicity, and high-throughput nature of this approach for phenotyping studies. The availability of a relative abundance factor and calculated intersystem extrapolation factor for the expressed recombinant enzymes facilitates easy scaling of in vitro data, enabling in vitro-in vivo extrapolation. Described in this unit is a high-throughput screen for identifying enzymes involved in the metabolism of NCEs. Emphasis is placed on the analysis of the human recombinant enzymes CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2B6, and CYP3A4, including the calculation of the intrinsic clearance for each. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

Quantitative site-specific phosphoproteomics of Trichoderma reesei signaling pathways upon induction of hydrolytic enzyme production

NARCIS (Netherlands)

Nguyen, E.V.; Imanishi, S.Y.; Haapaniemi, P.; Yadav, A.; Saloheimo, M.; Corthals, G.L.; Pakula, T.M.

2016-01-01

The filamentous fungus Trichoderma reesei is used for industrial production of secreted enzymes including carbohydrate active enzymes, such as cellulases and hemicellulases. The production of many of these enzymes by T. reesei is influenced by the carbon source it grows on, where the regulation

Mutual augmentation of the induction of the histamine-forming enzyme, histidine decarboxylase, between alendronate and immuno-stimulants (IL-1, TNF, and LPS), and its prevention by clodronate

International Nuclear Information System (INIS)

Deng Xue; Yu Zhiqian; Funayama, Hiromi; Shoji, Noriaki; Sasano, Takashi; Iwakura, Yoichiro; Sugawara, Shunji; Endo, Yasuo

2006-01-01

Nitrogen-containing bisphosphonates (N-BPs), powerful anti-bone-resorptive drugs, have inflammatory side effects, while histamine is not only an inflammatory mediator, but also an immuno-modifier. In murine models, a single intraperitoneal injection of an N-BP induces various inflammatory reactions, including the induction of the histamine-forming enzyme histidine decarboxylase (HDC) in tissues important in immune responses (such as liver, lungs, spleen, and bone marrow). Lipopolysaccharide (LPS) and the proinflammatory cytokines IL-1 and TNF are also capable of inducing HDC. We reported previously that in mice (i) the inflammatory actions of N-BPs depend on IL-1 (ii) N-BP pretreatment augments both LPS-stimulated IL-1 production and HDC induction, and (iii) the co-administration of clodronate (a non-N-BP) with an N-BP inhibits the latter's inflammatory actions (including HDC induction). Here, we add the new findings that (a) pretreatment with alendronate (a typical N-BP) augments both IL-1- and TNF-induced HDC elevations, (b) LPS pretreatment augments the alendronate-induced HDC elevation, (c) co-administration of clodronate with alendronate abolishes these augmentations, (d) alendronate does not induce HDC in IL-1-deficient mice even if they are pretreated with LPS, and (e) alendronate increases IL-1β in all tissues tested, but not in the serum. These results suggest that (1) there are mutual augmentations between alendronate and immuno-stimulants (IL-1, TNF, and LPS) in HDC induction, (2) tissue IL-1β is important in alendronate-stimulated HDC induction, and (3) combination use of clodronate may have the potential to reduce the inflammatory effects of alendronate (we previously found that clodronate, conveniently, does not inhibit the anti-bone-resorptive activity of alendronate)

Induction of peroxide and superoxide protective enzymes and physiological cross-protection against peroxide killing by a superoxide generator in Vibrio harveyi.

Science.gov (United States)

Vattanaviboon, Paiboon; Panmanee, Warunya; Mongkolsuk, Skorn

2003-04-11

Vibrio harveyi is a causative agent of destructive luminous vibriosis in farmed black tiger prawn (Penaeus monodon). V. harveyi peroxide and superoxide stress responses toward elevated levels of a superoxide generated by menadione were investigated. Exposure of V. harveyi to sub-lethal concentrations of menadione induced high expression of genes in both the OxyR regulon (e.g., a monofunctional catalase or KatA and an alkyl hydroperoxide reductase subunit C or AhpC), and the SoxRS regulon (e.g., a superoxide dismutase (SOD) and a glucose-6-phosphate dehydrogenase). V. harveyi expressed two detectable, differentially regulated SOD isozymes, [Mn]-SOD and [Fe]-SOD. [Fe]-SOD was expressed constitutively throughout the growth phase while [Mn]-SOD was expressed at the stationary phase and could be induced by a superoxide generator. Physiologically, pre-treatment of V. harveyi with menadione induced cross-protection against subsequent exposure to killing concentrations of H(2)O(2). This induced cross-protection required newly synthesized proteins. However, the treatment did not induce significant protection against exposures to killing concentrations of menadione itself or cross-protect against an organic hydroperoxide (tert-butyl hydroperoxide). Unexpectedly, growing V. harveyi in high-salinity media induced protection against menadione killing. This protection was independent of SOD induction. Stationary-phase cells were more resistant to menadione killing than exponential-phase cells. The induction of oxidative stress protective enzymes and stress-altered physiological responses could play a role in the survival of this bacterium in the host marine crustaceans.

Preclinical electrogastrography in experimental pigs

Science.gov (United States)

Květina, Jaroslav; Varayil, Jithinraj Edakkanambeth; Ali, Shahzad Marghoob; Kuneš, Martin; Bureš, Jan; Tachecí, Ilja; Rejchrt, Stanislav; Kopáčová, Marcela

2010-01-01

Surface electrogastrography (EGG) is a non-invasive means of recording gastric myoelectric activity or slow waves from cutaneous leads placed over the stomach. This paper provides a comprehensive review of preclinical EGG. Our group recently set up and worked out the methods for EGG in experimental pigs. We gained our initial experience in the use of EGG in assessment of porcine gastric myoelectric activity after volume challenge and after intragastric administration of itopride and erythromycin. The mean dominant frequency in pigs is comparable with that found in humans. EGG in experimental pigs is feasible. Experimental EGG is an important basis for further preclinical projects in pharmacology and toxicology. PMID:21217873

Indoleamine 2,3-dioxygenase-dependent tryptophan metabolites contribute to tolerance induction during allergen immunotherapy in a mouse model

NARCIS (Netherlands)

Taher, Yousef A.; Piavaux, Benoit J. A.; Gras, Renee; van Esch, Betty C. A. M.; Hofman, Gerard A.; Bloksma, Nanne; Henricks, Paul A. J.; van Oosterhout, Antoon J. M.

Background: The tryptophan-catabolizing enzyme indoleamine 2,3-dioxygenase (IDO) has been implicated in immune suppression and tolerance induction. Objective: We examined (1) whether IDO activity is required during tolerance induction by allergen immunotherapy or for the subsequent suppressive

Xylanolytic enzyme systems in Arthrobacter sp MTCC 5214 and Lactobacillus sp.

Digital Repository Service at National Institute of Oceanography (India)

Khandeparker, R.; Jalal, T.

The production of extracellular xylanolytic enzymes such as xylanase, alfa-L-arabinofuranosidase (alfa-l-AFase), and acetyl xylan esterase (Axe) by marine Arthrobacter sp and Lactobacillus sp was investigated using different carbon sources Induction...

Preclinical and clinical safety studies on DNA vaccines.

NARCIS (Netherlands)

Schalk, Johanna A C; Mooi, Frits R; Berbers, Guy A M; Aerts, Leon A G J M van; Ovelgönne, Hans; Kimman, Tjeerd G

2007-01-01

DNA vaccines are based on the transfer of genetic material, encoding an antigen, to the cells of the vaccine recipient. Despite high expectations of DNA vaccines as a result of promising preclinical data their clinical utility remains unproven. However, much data is gathered in preclinical and

Preclinical Cancer Chemoprevention Studies Using Animal Model of Inflammation-Associated Colorectal Carcinogenesis

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Takuji [Cytopatholgy Division, Tohkai Cytopathology Institute, Cancer Research and Prevention (TCI-CaRP), 5-1-2 Minami-uzura, Gifu 500-8285 (Japan); Department of Tumor Pathology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan)

2012-07-16

Inflammation is involved in all stages of carcinogenesis. Inflammatory bowel disease, such as ulcerative colitis and Crohn’s disease is a longstanding inflammatory disease of intestine with increased risk for colorectal cancer (CRC). Several molecular events involved in chronic inflammatory process are reported to contribute to multi-step carcinogenesis of CRC in the inflamed colon. They include over-production of free radicals, reactive oxygen and nitrogen species, up-regulation of inflammatory enzymes in arachidonic acid biosynthesis pathway, up-regulation of certain cytokines, and intestinal immune system dysfunction. In this article, firstly I briefly introduce our experimental animal models where colorectal neoplasms rapidly develop in the inflamed colorectum. Secondary, data on preclinical cancer chemoprevention studies of inflammation-associated colon carcinogenesis by morin, bezafibrate, and valproic acid, using this novel inflammation-related colorectal carcinogenesis model is described.

Neuropsychiatric symptoms predict hypometabolism in preclinical Alzheimer disease.

Science.gov (United States)

Ng, Kok Pin; Pascoal, Tharick A; Mathotaarachchi, Sulantha; Chung, Chang-Oh; Benedet, Andréa L; Shin, Monica; Kang, Min Su; Li, Xiaofeng; Ba, Maowen; Kandiah, Nagaendran; Rosa-Neto, Pedro; Gauthier, Serge

2017-05-09

To identify regional brain metabolic dysfunctions associated with neuropsychiatric symptoms (NPS) in preclinical Alzheimer disease (AD). We stratified 115 cognitively normal individuals into preclinical AD (both amyloid and tau pathologies present), asymptomatic at risk for AD (either amyloid or tau pathology present), or healthy controls (no amyloid or tau pathology present) using [ 18 F]florbetapir PET and CSF phosphorylated tau biomarkers. Regression and voxel-based regression models evaluated the relationships between baseline NPS measured by the Neuropsychiatric Inventory (NPI) and baseline and 2-year change in metabolism measured by [ 18 F]fluorodeoxyglucose (FDG) PET. Individuals with preclinical AD with higher NPI scores had higher [ 18 F]FDG uptake in the posterior cingulate cortex (PCC), ventromedial prefrontal cortex, and right anterior insula at baseline. High NPI scores predicted subsequent hypometabolism in the PCC over 2 years only in individuals with preclinical AD. Sleep/nighttime behavior disorders and irritability and lability were the components of the NPI that drove this metabolic dysfunction. The magnitude of NPS in preclinical cases, driven by sleep behavior and irritability domains, is linked to transitory metabolic dysfunctions within limbic networks vulnerable to the AD process and predicts subsequent PCC hypometabolism. These findings support an emerging conceptual framework in which NPS constitute an early clinical manifestation of AD pathophysiology. Copyright © 2017 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.

Regulation of the cellulolytic system in Trichoderma reesei by sophorose: induction of cellulase and repression of beta-glucosidase.

OpenAIRE

Sternberg, D; Mandels, G R

1980-01-01

Sophorose has two regulatory roles in the production of cellulase enzymes in Trichoderma reesei: beta-glucosidase repression and cellulase induction. Sophorose also is hydrolyzed by the mycelial-associated beta-glucosidase. Repression of beta-glucosidase reduces sophorose hydrolysis and thus may increase cellulase induction.

Effects of carbon and nitrogen sources on the induction and ...

African Journals Online (AJOL)

user

about the induction and repression mechanism of this hydrolytic enzyme. This report ... chitin as a sole source of carbon followed by the medium containing an extra nitrogen source, yeast extract. .... against fluorescent background by UV illumination. Statistical ..... Virulence Associated with Native and Mutant Isolates of an.

Effects of carbon and nitrogen sources on the induction and ...

African Journals Online (AJOL)

Effects of carbon and nitrogen sources on the induction and repression of chitinase enzyme from Beauveria bassiana isolates. Priyanka Dhar, Gurvinder Kaur. Abstract. Beauveria bassiana a natural soil borne insect pathogen is being used effectively these days in integrated pest management system. Foliar application of ...

Alpha Adrenergic Induction of Transport of Lysosomal Enzyme across the Blood-Brain Barrier.

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Akihiko Urayama

Full Text Available The impermeability of the adult blood-brain barrier (BBB to lysosomal enzymes impedes the ability to treat the central nervous system manifestations of lysosomal storage diseases. Here, we found that simultaneous stimulation of the alpha1 and alpha2 adrenoreceptor restores in adult mice the high rate of transport for the lysosomal enzyme P-GUS that is seen in neonates but lost with development. Beta adrenergics, other monoamines, and acetylcholine did not restore this transport. A high dose (500 microg/mouse of clonidine, a strong alpha2 and weak alpha1 agonist, was able to act as monotherapy in the stimulation of P-GUS transport. Neither use of alpha1 plus alpha2 agonists nor the high dose clonidine disrupted the BBB to albumin. In situ brain perfusion and immunohistochemistry studies indicated that adrengerics act on transporters already at the luminal surface of brain endothelial cells. These results show that adrenergic stimulation, including monotherapy with clonidine, could be key for CNS enzyme replacement therapy.

Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

Science.gov (United States)

Semsang, Nuananong; Yu, LiangDeng

2013-07-01

Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29-60 keV and ion fluences of 1 × 1016 ions cm-2. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

NCI Pediatric Preclinical Testing Consortium

Science.gov (United States)

NCI has awarded grants to five research teams to participate in its Pediatric Preclinical Testing Consortium, which is intended to help to prioritize which agents to pursue in pediatric clinical trials.

Production of xylan-degrading enzymes by a Trichoderma harzianum strain

Directory of Open Access Journals (Sweden)

Cacais André O.Guerreiro

2001-01-01

Full Text Available Trichoderma harzianum strain 4 produced extracellular xylan-degrading enzymes, namely beta-xylanase, beta-xylosidase and alpha-arabinofuranosidase, when grown in liquid medium cultures containing oat spelt xylan as inducer. Cellulase activity was not detected. The pattern of xylan-degrading enzymes induction was influenced by the form of xylan present in the medium. They were detected in different incubation periods. Electrophoretic separation of the proteins from liquid culture filtrates by SDS-PAGE showed a variety of bands with high and low molecular weights.

Two-step polymer- and liposome-enzyme prodrug therapies for cancer: PDEPT and PELT concepts and future perspectives.

Science.gov (United States)

Scomparin, Anna; Florindo, Helena F; Tiram, Galia; Ferguson, Elaine L; Satchi-Fainaro, Ronit

2017-09-01

Polymer-directed enzyme prodrug therapy (PDEPT) and polymer enzyme liposome therapy (PELT) are two-step therapies developed to provide anticancer drugs site-selective intratumoral accumulation and release. Nanomedicines, such as polymer-drug conjugates and liposomal drugs, accumulate in the tumor site due to extravasation-dependent mechanism (enhanced permeability and retention - EPR - effect), and further need to cross the cellular membrane and release their payload in the intracellular compartment. The subsequent administration of a polymer-enzyme conjugate able to accumulate in the tumor tissue and to trigger the extracellular release of the active drug showed promising preclinical results. The development of polymer-enzyme, polymer-drug conjugates and liposomal drugs had undergone a vast advancement over the past decades. Several examples of enzyme mimics for in vivo therapy can be found in the literature. Moreover, polymer therapeutics often present an enzyme-sensitive mechanism of drug release. These nanomedicines can thus be optimal substrates for PDEPT and this review aims to provide new insights and stimuli toward the future perspectives of this promising combination. Copyright © 2017 Elsevier B.V. All rights reserved.

Transglutaminase induction by various cell death and apoptosis pathways.

Science.gov (United States)

Fesus, L; Madi, A; Balajthy, Z; Nemes, Z; Szondy, Z

1996-10-31

Clarification of the molecular details of forms of natural cell death, including apoptosis, has become one of the most challenging issues of contemporary biomedical sciences. One of the effector elements of various cell death pathways is the covalent cross-linking of cellular proteins by transglutaminases. This review will discuss the accumulating data related to the induction and regulation of these enzymes, particularly of tissue type transglutaminase, in the molecular program of cell death. A wide range of signalling pathways can lead to the parallel induction of apoptosis and transglutaminase, providing a handle for better understanding the exact molecular interactions responsible for the mechanism of regulated cell death.

Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

Energy Technology Data Exchange (ETDEWEB)

Semsang, Nuananong, E-mail: nsemsang@gmail.com [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, LiangDeng [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

2013-07-15

Highlights: ► Ion beam bombarded rice seeds in vacuum. ► Studied seed survival from the ion bombardment. ► Determined various antioxidant enzyme activities and lipid peroxidation level. ► Discussed vacuum, ion species and ion energy effects. ► Attributed the changes to free radical formation due to ion bombardment. -- Abstract: Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29–60 keV and ion fluences of 1 × 10{sup 16} ions cm{sup −2}. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

Genotoxic activity and induction of biotransformation enzymes in two human cell lines after treatment by Erika fuel extract.

Science.gov (United States)

Amat-Bronnert, Agnès; Castegnaro, Marcel; Pfohl-Leszkowicz, Annie

2007-01-01

On 12 December 1999, the tanker Erika broke in two parts at about 60km from the Brittany French coasts (Point of Penmarc'h, Sud Finistère, France). About 10,000tonnes of heavy oil fuel were released in the sea. DNA adduct have been detected in fish liver and mussels digestive gland exposed to the Erika oil spill. In order to investigate the mechanism by which Erika fuel extract exhibits genotoxic effects the induction of DNA adducts by an Erika fuel extract have been analysed on two cell lines, human epithelial bronchial cells (WI) and human hepatoma cells. DNA adducts, reflected by a diagonal radioactive zone and individual adducts are detected only in hepatoma cells indicating biotransformation via CYP 1A2 and CYP 1B1. In addition, Erika fuel extract induces some metabolizing enzymes such CYP 1A2, COX2 and 5-LOX, the two later are involved in cancer processes. Formation of leucotrienes B4 (LTB(4)), a mediator playing a role in inflammation, is induced in epithelial bronchial cells. Since inhalation is one of the ways of contamination for human, the above results are important for human health and prevention. Copyright © 2006 Elsevier B.V. All rights reserved.

Perspective: Recommendations for benchmarking pre-clinical studies of nanomedicines

Science.gov (United States)

Dawidczyk, Charlene M.; Russell, Luisa M.; Searson, Peter C.

2015-01-01

Nanoparticle-based delivery systems provide new opportunities to overcome the limitations associated with traditional small molecule drug therapy for cancer, and to achieve both therapeutic and diagnostic functions in the same platform. Pre-clinical trials are generally designed to assess therapeutic potential and not to optimize the design of the delivery platform. Consequently, progress in developing design rules for cancer nanomedicines has been slow, hindering progress in the field. Despite the large number of pre-clinical trials, several factors restrict comparison and benchmarking of different platforms, including variability in experimental design, reporting of results, and the lack of quantitative data. To solve this problem, we review the variables involved in the design of pre-clinical trials and propose a protocol for benchmarking that we recommend be included in in vivo pre-clinical studies of drug delivery platforms for cancer therapy. This strategy will contribute to building the scientific knowledge base that enables development of design rules and accelerates the translation of new technologies. PMID:26249177

Modeling the Western Diet for Preclinical Investigations.

Science.gov (United States)

Hintze, Korry J; Benninghoff, Abby D; Cho, Clara E; Ward, Robert E

2018-05-01

Rodent models have been invaluable for biomedical research. Preclinical investigations with rodents allow researchers to investigate diseases by using study designs that are not suitable for human subjects. The primary criticism of preclinical animal models is that results are not always translatable to humans. Some of this lack of translation is due to inherent differences between species. However, rodent models have been refined over time, and translatability to humans has improved. Transgenic animals have greatly aided our understanding of interactions between genes and disease and have narrowed the translation gap between humans and model animals. Despite the technological innovations of animal models through advances in genetics, relatively little attention has been given to animal diets. Namely, developing diets that replicate what humans eat will help make animal models more relevant to human populations. This review focuses on commonly used rodent diets that are used to emulate the Western dietary pattern in preclinical studies of obesity and type 2 diabetes, nonalcoholic liver disease, maternal nutrition, and colorectal cancer.

The basics of preclinical drug development for neurodegenerative disease indications.

Science.gov (United States)

Steinmetz, Karen L; Spack, Edward G

2009-06-12

Preclinical development encompasses the activities that link drug discovery in the laboratory to initiation of human clinical trials. Preclinical studies can be designed to identify a lead candidate from several hits; develop the best procedure for new drug scale-up; select the best formulation; determine the route, frequency, and duration of exposure; and ultimately support the intended clinical trial design. The details of each preclinical development package can vary, but all have some common features. Rodent and nonrodent mammalian models are used to delineate the pharmacokinetic profile and general safety, as well as to identify toxicity patterns. One or more species may be used to determine the drug's mean residence time in the body, which depends on inherent absorption, distribution, metabolism, and excretion properties. For drugs intended to treat Alzheimer's disease or other brain-targeted diseases, the ability of a drug to cross the blood brain barrier may be a key issue. Toxicology and safety studies identify potential target organs for adverse effects and define the Therapeutic Index to set the initial starting doses in clinical trials. Pivotal preclinical safety studies generally require regulatory oversight as defined by US Food and Drug Administration (FDA) Good Laboratory Practices and international guidelines, including the International Conference on Harmonization. Concurrent preclinical development activities include developing the Clinical Plan and preparing the new drug product, including the associated documentation to meet stringent FDA Good Manufacturing Practices regulatory guidelines. A wide range of commercial and government contract options are available for investigators seeking to advance their candidate(s). Government programs such as the Small Business Innovative Research and Small Business Technology Transfer grants and the National Institutes of Health Rapid Access to Interventional Development Pilot Program provide funding and

Effect of thiabendazole on some rat hepatic xenobiotic metabolising enzymes

NARCIS (Netherlands)

Price, R.J.; Scott, M.P.; Walters, D.G.; Stierum, R.H.; Groten, J.P.; Meredith, C.; Lake, B.G.

2004-01-01

The effect of thiabendazole (TB) on some rat hepatic xenobiotic metabolising enzymes has been investigated. Male Sprague-Dawley rats were fed control diet or diets containing 102-5188 ppm TB for 28 days. As a positive control for induction of hepatic xenobiotic metabolism, rats were also fed diets

Simple Laboratory Exercise for Induction of Beta-Mannanase from "Aspergillus niger"

Science.gov (United States)

Mulimani, V. H.; Naganagouda, K.

2010-01-01

This laboratory experiment was designed for Biochemistry, Biotechnology, Microbiology, and Food Technology students of undergraduate and postgraduate courses. The experiment shows the advantages of using agricultural waste, copra mannan as potent inducer of [beta]-mannanase. The students were able to compare the enzyme induction by commercial…

Radiosensitivity of the induction of early enzymes by. gamma. -irradiated T7-phages

Energy Technology Data Exchange (ETDEWEB)

Bopp, E

1975-01-01

The radiosensitivity of the ability of the bacteriophage T7 to produce polymerase and lysozyme during its reproduction cycle is investigated. B-cells of Escherichia coli were infected with /sup 60/Co-..gamma..-irradiated T7 phages. From the extracts of the cells opened by ultrasonic waves, the amount of enzymes produced is determined with the aid of special enzyme tests. The fraction of inactivated phages able to produce RNA polymerase is higher than the fraction with intact DNA double strands and higher than the fraction able to inject DNA. The lowest fraction is that of inactivated phages producing lysozyme.

Induction of radiation resistance and radio-protective mechanism. On the reactive oxygen and free radical

International Nuclear Information System (INIS)

Yukawa, Osami

2003-01-01

Radical scavenging system for reactive oxygen species (ROS) leading to radio-protection is reviewed on findings in animals, tissues and cells. Protection against oxygen toxicity in evolution can be seen in anaerobes' superoxide dismutase (SOD) over 3500 million years ago. ROS is generated endogenously and also by radiation. However, the intracellular sites of the generated ROS are different depending on its cause. The protection is done through enzymes like SOD, peroxidase, catalase, glutathione-related enzymes and through substances like GSH, α-tocopherol, ascorbic acid etc. Induction of ROS scavenging substances related with radio-resistance includes the responses to the low dose radiation (5-50 cGy) in those enzymes described above; to middle to high dose radiation (1-30 Gy) in a similar and in other unknown mechanisms; to exposure of ROS like H 2 O 2 at low concentration; and to antioxidant treatment. The cross-resistance between radiation and drugs suggests necessity of this induction. (N.I.)

Synthesis of enzymes connected with mycoparasitism by ectomycorrhizal fungi.

Science.gov (United States)

Mucha, Joanna; Dahm, Hanna; Strzelczyk, Edmund; Werner, Antoni

2006-03-01

The production of enzymes involved in mycoparasitism by several strains of ectomycorrhizal fungi: Amanita muscaria (16-3), Laccaria laccata (9-12), L. laccata (9-1), Suillus bovinus (15-4), S. bovinus (15-3), S. luteus (14-7) on different substrates such as colloidal chitin, mycelia of Trichoderma harzianum, T. virens and Mucor hiemalis was examined. Chitinases and beta-1,3-glucanases were assayed spectrophotometrically by measuring the amount of reducing sugars releasing from suitable substrate by means of Miller's method. Beta-glucosidases were determined by measuring the amount of p-nitrophenol released from p-nitrophenyl-beta-D-glucopyranoside. It was observed that A. muscaria (16-3) and L. laccata (9-12) biosynthesized the highest activity of enzymes in contrast to the strains of S. bovinus and S. luteus. The mycelium of T. harzianum turned out to be the best substrate for the induction of beta-1,3-glucanases and beta-glucosidases for both strains of L. laccata, although the difference in the induction of chitinases in the presence of mycelia of different species of Trichoderma was not indicated.

Study partners should be required in preclinical Alzheimer's disease trials.

Science.gov (United States)

Grill, Joshua D; Karlawish, Jason

2017-12-06

In an effort to intervene earlier in Alzheimer's disease (AD), clinical trials are testing promising candidate therapies in preclinical disease. Preclinical AD trial participants are cognitively normal, functionally independent, and autonomous decision-makers. Yet, like AD dementia trials, preclinical trials require dual enrollment of a participant and a knowledgeable informant, or study partner. The requirement of dyadic enrollment is a barrier to recruitment and may present unique ethical challenges. Despite these limitations, the requirement should continue. Study partners may be essential to ensure participant safety and wellbeing, including overcoming distress related to biomarker disclosure and minimizing risk for catastrophic reactions and suicide. The requirement may maximize participant retention and ensure data integrity, including that study partners are the source of data that will ultimately instruct whether a new treatment has a clinical benefit and meaningful impact on the population health burden associated with AD. Finally, study partners are needed to ensure the scientific and clinical value of trials. Preclinical AD will represent a new model of care, in which persons with no symptoms are informed of probable cognitive decline and eventual dementia. The rationale for early diagnosis in symptomatic AD is equally applicable in preclinical AD-to minimize risk, maximize quality of life, and ensure optimal planning and communication. Family members and other sources of support will likely be essential to the goals of this new model of care for preclinical AD patients and trials must instruct this clinical practice.

A Metadata Analysis of Oxidative Stress Etiology in Preclinical Amyotrophic Lateral Sclerosis: Benefits of Antioxidant Therapy

Directory of Open Access Journals (Sweden)

Leila Bond

2018-01-01

Full Text Available Oxidative stress, induced by an imbalance of free radicals, incites neurodegeneration in Amyotrophic Lateral Sclerosis (ALS. In fact, a mutation in antioxidant enzyme superoxide dismutase 1 (SOD1 accounts for 20% of familial ALS cases. However, the variance among individual studies examining ALS oxidative stress clouds corresponding conclusions. Therefore, we construct a comprehensive, temporal view of oxidative stress and corresponding antioxidant therapy in preclinical ALS by mining published quantitative experimental data and performing metadata analysis of 41 studies. In vitro aggregate analysis of innate oxidative stress inducers, glutamate and hydrogen peroxide, revealed 70–90% of cell death coincides to inducer exposure equivalent to 30–50% peak concentration (p < 0.05. A correlative plateau in cell death suggests oxidative stress impact is greatest in early-stage neurodegeneration. In vivo SOD1-G93A transgenic ALS mouse aggregate analysis of heat shock proteins (HSPs revealed HSP levels are 30% lower in muscle than spine (p < 0.1. Overall spine HSP levels, including HSP70, are mildly upregulated in SOD1-G93A mice compared to wild type, but not significantly (p > 0.05. Thus, innate HSP compensatory responses to oxidative stress are simply insufficient, a result supportive of homeostatic system instability as central to ALS etiology. In vivo aggregate analysis of antioxidant therapy finds SOD1-G93A ALS mouse survival duration significantly increases by 11.2% (p << 0.001 but insignificantly decreases onset age by 2%. Thus, the aggregate antioxidant treatment effect on survival in preclinical ALS is not sufficient to overcome clinical heterogeneity, which explains the literature disparity between preclinical and clinical antioxidant survival benefit. The aggregate effect sizes on preclinical ALS survival and onset illustrate that present antioxidants, alone, are not sufficient to halt ALS, which underscores its multi-factorial nature

The role of microsomal enzyme inducers in the reduction of misonidazole neurotoxicity

International Nuclear Information System (INIS)

Jones, D.H.; Bleehen, N.M.; Workman, P.; Smith, N.C.

1983-01-01

It has been shown that phenytoin, 300 mg daily for one week, produces consistent hepatic microsomal enzyme induction, resulting in a decrease of 25% in misonidazole half-life, without causing any toxicity per se. A longer period of administration gives only a slightly greater induction. Phenobarbitone in a daily dose of 90 mg causes a reduction of 18% and 23% in misonidazole half-life after 1 and 2 weeks' pre-treatment respectively, but is less suitable clinically because of its sedative effect. A further series of studies using phenytoin as the inducing agent has shown that, despite adequate enzyme induction and increased misonidazole metabolism, it is impossible to increase the total dose of misonidazole beyond the usually accepted value of 12 g/m 2 because of unacceptable neuropathy (a rate of 50% at a dose of 14 g/m 2 over three weeks). In single doses of above 3.0-4.0 g of misonidazole, severe nausea and vomiting are prominent, so that this side effect is a determining factor in the treatment fractionation. Audiometric studies show no correlation between the incidence of peripheral neuropathy and abnormal audiograms, and have no value in the early prediction of neurotoxicity. (author)

Induction of spermidine/spermine N1-acetyltransferase by methylglyoxal bis(guanylhydrazone).

Science.gov (United States)

Pegg, A E; Erwin, B G; Persson, L

1985-10-17

The anti-tumor agent methylglyoxal bis(guanylhydrazone) was found to be a competitive inhibitor of spermidine/spermine N1-acetyltransferase with a Ki of about 8 microM. Treatment of rats with this drug lead to a very large increase in the total amount of spermidine/spermine N1-acetyltransferase in liver, kidney and spleen. The total increase as measured using a specific antiserum amounted to 700-fold in liver and 100-fold in kidney within 18 h of treatment with 80 mg/kg doses. At least part of this induction was due to a pronounced increase in the half-life of the acetyltransferase which increased from 15 min to more than 12 h. The very large increase in the amount of the enzyme is likely to overwhelm the direct inhibition, and a net increase in the acetylation of polyamines by this enzyme would be expected to occur after treatment with methylglyoxal bis(guanylhydrazone). The acetylated polyamines are known to be rapidly degraded by polyamine oxidase producing putrescine. Direct evidence that a substantial part of the increase in the content of putrescine in the liver of rats treated with methylglyoxal bis(guanylhydrazone) occurs via the induction of this acetylase/oxidase pathway was obtained. These results indicate that methylglyoxal bis(guanylhydrazone) affects cellular polyamine levels not only by means of its inhibitory effect on S-adenosylmethionine decarboxylase and diamine oxidase but also by the induction of spermidine/spermine N1-acetyltransferase. They also raise the possibility that the enormous increase in this enzyme which occurs with higher doses may contribute to the very severe toxicity of methylglyoxal bis(guanylhydrazone).

A study of overproduction and enhanced secretion of enzymes. Quarterly report

Energy Technology Data Exchange (ETDEWEB)

Dashek, W.V.

1993-09-01

Wood decay within forests, a significant renewable photosynthetic energy resource, is caused primarily by Basidiomycetous fungi, e.g., white rot fungi. These organisms possess the ability to degrade lignin, cellulose and hemicellulose, the main organic polymers of wood. In the case of the white rot fungi, e.g., Coriolus versicolor, the capacity results from the fungus` ability to elaborate extracellular cellulolytic and ligninolytic enzymes. With regard to the latter, at least one of the enzymes, polyphenol oxidase (PPO) appears within a defined growth medium. This proposal focuses on the over-production and enhanced secretion of PPO, cellulase and lignin peroxidase. There are two major sections to the proposal: (1) overproduction of lignocellulolytic enzymes by genetic engineering methodologies and hyper-production and enhanced secretion of these enzymes by biochemical/electro microscopical techniques and (2) the biochemical/electron microscopical method involves substrate induction and the time-dependent addition of respiration and PPO enzymes.

Trial watch – inhibiting PARP enzymes for anticancer therapy

Science.gov (United States)

Sistigu, Antonella; Manic, Gwenola; Obrist, Florine; Vitale, Ilio

2016-01-01

ABSTRACT Poly(ADP-ribose) polymerases (PARPs) are a members of family of enzymes that catalyze poly(ADP-ribosyl)ation (PARylation) and/or mono(ADP-ribosyl)ation (MARylation), two post-translational protein modifications involved in crucial cellular processes including (but not limited to) the DNA damage response (DDR). PARP1, the most abundant family member, is a nuclear protein that is activated upon sensing distinct types of DNA damage and contributes to their resolution by PARylating multiple DDR players. Recent evidence suggests that, along with DDR, activated PARP1 mediates a series of prosurvival and proapoptotic processes aimed at preserving genomic stability. Despite this potential oncosuppressive role, upregulation and/or overactivation of PARP1 or other PARP enzymes has been reported in a variety of human neoplasms. Over the last few decades, several pharmacologic inhibitors of PARP1 and PARP2 have been assessed in preclinical and clinical studies showing potent antineoplastic activity, particularly against homologous recombination (HR)-deficient ovarian and breast cancers. In this Trial Watch, we describe the impact of PARP enzymes and PARylation in cancer, discuss the mechanism of cancer cell killing by PARP1 inactivation, and summarize the results of recent clinical studies aimed at evaluating the safety and therapeutic profile of PARP inhibitors in cancer patients. PMID:27308587

The basics of preclinical drug development for neurodegenerative disease indications

Directory of Open Access Journals (Sweden)

Spack Edward G

2009-06-01

Full Text Available Abstract Preclinical development encompasses the activities that link drug discovery in the laboratory to initiation of human clinical trials. Preclinical studies can be designed to identify a lead candidate from several hits; develop the best procedure for new drug scale-up; select the best formulation; determine the route, frequency, and duration of exposure; and ultimately support the intended clinical trial design. The details of each preclinical development package can vary, but all have some common features. Rodent and nonrodent mammalian models are used to delineate the pharmacokinetic profile and general safety, as well as to identify toxicity patterns. One or more species may be used to determine the drug's mean residence time in the body, which depends on inherent absorption, distribution, metabolism, and excretion properties. For drugs intended to treat Alzheimer's disease or other brain-targeted diseases, the ability of a drug to cross the blood brain barrier may be a key issue. Toxicology and safety studies identify potential target organs for adverse effects and define the Therapeutic Index to set the initial starting doses in clinical trials. Pivotal preclinical safety studies generally require regulatory oversight as defined by US Food and Drug Administration (FDA Good Laboratory Practices and international guidelines, including the International Conference on Harmonisation. Concurrent preclinical development activities include developing the Clinical Plan and preparing the new drug product, including the associated documentation to meet stringent FDA Good Manufacturing Practices regulatory guidelines. A wide range of commercial and government contract options are available for investigators seeking to advance their candidate(s. Government programs such as the Small Business Innovative Research and Small Business Technology Transfer grants and the National Institutes of Health Rapid Access to Interventional Development Pilot

Role of microsomal enzyme inducers in the reduction of misonidazole neurotoxicity

Energy Technology Data Exchange (ETDEWEB)

Jones, D.H.; Bleehen, N.M.; Workman, P.; Smith, N.C. (Cambridge Univ. (UK). Dept. of Clinical Oncology and Radiotherapeutics; Addenbrooke' s Hospital, Cambridge (UK))

1983-11-01

It has been shown that phenytoin, 300 mg daily for one week, produces consistent hepatic microsomal enzyme induction, resulting in a decrease of 25% in misonidazole half-life, without causing any toxicity per se. A longer period of administration gives only a slightly greater induction. Phenobarbitone in a daily dose of 90 mg causes a reduction of 18% and 23% in misonidazole half-life after 1 and 2 weeks' pre-treatment respectively, but is less suitable clinically because of its sedative effect. A further series of studies using phenytoin as the inducing agent has shown that, despite adequate enzyme induction and increased misonidazole metabolism, it is impossible to increase the total dose of misonidazole beyond the usually accepted value of 12 g/m/sup 2/ because of unacceptable neuropathy (a rate of 50% at a dose of 14 g/m/sup 2/ over three weeks). In single doses of above 3.0-4.0 g of misonidazole, severe nausea and vomiting are prominent, so that this side effect is a determining factor in the treatment fractionation. Audiometric studies show no correlation between the incidence of peripheral neuropathy and abnormal audiograms, and have no value in the early prediction of neurotoxicity.

The Ubiquitin-Conjugating Enzyme Gene Family in Longan (Dimocarpus longan Lour.: Genome-Wide Identification and Gene Expression during Flower Induction and Abiotic Stress Responses

Directory of Open Access Journals (Sweden)

Dengwei Jue

2018-03-01

Full Text Available Ubiquitin-conjugating enzymes (E2s or UBC enzymes play vital roles in plant development and combat various biotic and abiotic stresses. Longan (Dimocarpus longan Lour. is an important fruit tree in the subtropical region of Southeast Asia and Australia; however the characteristics of the UBC gene family in longan remain unknown. In this study, 40 D. longan UBC genes (DlUBCs, which were classified into 15 groups, were identified in the longan genome. An RNA-seq based analysis showed that DlUBCs showed distinct expression in nine longan tissues. Genome-wide RNA-seq and qRT-PCR based gene expression analysis revealed that 11 DlUBCs were up- or down-regualted in the cultivar “Sijimi” (SJ, suggesting that these genes may be important for flower induction. Finally, qRT-PCR analysis showed that the mRNA levels of 13 DlUBCs under SA (salicylic acid treatment, seven under methyl jasmonate (MeJA treatment, 27 under heat treatment, and 16 under cold treatment were up- or down-regulated, respectively. These results indicated that the DlUBCs may play important roles in responses to abiotic stresses. Taken together, our results provide a comprehensive insight into the organization, phylogeny, and expression patterns of the longan UBC genes, and therefore contribute to the greater understanding of their biological roles in longan.

Cellulase enzyme production during continuous culture growth of Sporotrichum (Chrysosporium) thermophile

Energy Technology Data Exchange (ETDEWEB)

Cossar, D; Canevascini, G

1986-07-01

The cellulolytic fungus Sporotrichum (Chrysosporium) thermophile produces an extracellular cellobiose dehydrogenase during batch culture on cellulose or cellobiose. In chemostat culture at pH 5.6 on cellobiose this enzyme was produced in parallel with endo-cellulase. At pH 5.0 in continuous or fed-batch culture such a pattern was not evident. At constant growth rate in a chemostat with varying pH, activity of these enzymes was found to be poorly correlated. Thus the induction of cellobiose dehydrogenase shows a dependence on pH and cellobiose concentration which is different to that for endo-cellulase. The natural inducer of these enzymes and the role of cellubiose dehydrogenase remain to be elucidated.

Development, validation, and application of ELISA for detection of anti-HD105 antibodies in pre-clinical safety evaluation using monkeys.

Science.gov (United States)

Choi, Woo Hyuck; Jo, Hye Ryun; Jeon, Eun-Jeong; Youm, So-Young; Jeon, Jang Su; Son, Yong-Gyu; You, Weon-Kyoo; Koh, Woo Suk; Lee, Sang Hoon; Kim, Sang Kyum

2016-11-30

Unwanted immunogenicity of protein therapeutics can result in severe side effects and should be assessed in animals before applying the treatment to humans. Monkeys are the most relevant choice for pre-clinical toxicity testing of antibody-based therapeutics. To assess the immunogenicity of HD105, a novel antibody therapeutic that targets both vascular endothelial growth factor and Delta-like-ligand 4, a bridging enzyme-linked immunosorbent assay was developed as an anti-drug antibody (ADA) assay and validated for use in pre-clinical studies using non-human primates. This method was found to have suitable assay sensitivity, intra- and inter-assay precision, confirmation, drug tolerance, recovery, and sample stability for measuring ADA in monkey serum samples. The results showed that ADA elevation occurred following repeated doses of HD105, and that ADA production was negatively associated with serum HD105 concentration. These results suggest that intravenous administration of HD105 induces production of ADA in monkeys and that the detection of ADA may be negatively influenced by free HD105 in serum. Copyright © 2016 Elsevier B.V. All rights reserved.

The Economics of Reproducibility in Preclinical Research.

Directory of Open Access Journals (Sweden)

Leonard P Freedman

2015-06-01

Full Text Available Low reproducibility rates within life science research undermine cumulative knowledge production and contribute to both delays and costs of therapeutic drug development. An analysis of past studies indicates that the cumulative (total prevalence of irreproducible preclinical research exceeds 50%, resulting in approximately US$28,000,000,000 (US$28B/year spent on preclinical research that is not reproducible-in the United States alone. We outline a framework for solutions and a plan for long-term improvements in reproducibility rates that will help to accelerate the discovery of life-saving therapies and cures.

USHERING IN THE STUDY AND TREATMENT OF PRECLINICAL ALZHEIMER DISEASE

Science.gov (United States)

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

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. PMID:23752908

The Devil Is in the Details: Incomplete Reporting in Preclinical Animal Research.

Science.gov (United States)

Avey, Marc T; Moher, David; Sullivan, Katrina J; Fergusson, Dean; Griffin, Gilly; Grimshaw, Jeremy M; Hutton, Brian; Lalu, Manoj M; Macleod, Malcolm; Marshall, John; Mei, Shirley H J; Rudnicki, Michael; Stewart, Duncan J; Turgeon, Alexis F; McIntyre, Lauralyn

2016-01-01

Incomplete reporting of study methods and results has become a focal point for failures in the reproducibility and translation of findings from preclinical research. Here we demonstrate that incomplete reporting of preclinical research is not limited to a few elements of research design, but rather is a broader problem that extends to the reporting of the methods and results. We evaluated 47 preclinical research studies from a systematic review of acute lung injury that use mesenchymal stem cells (MSCs) as a treatment. We operationalized the ARRIVE (Animal Research: Reporting of In Vivo Experiments) reporting guidelines for pre-clinical studies into 109 discrete reporting sub-items and extracted 5,123 data elements. Overall, studies reported less than half (47%) of all sub-items (median 51 items; range 37-64). Across all studies, the Methods Section reported less than half (45%) and the Results Section reported less than a third (29%). There was no association between journal impact factor and completeness of reporting, which suggests that incomplete reporting of preclinical research occurs across all journals regardless of their perceived prestige. Incomplete reporting of methods and results will impede attempts to replicate research findings and maximize the value of preclinical studies.

Preclinical and Clinical Assessment of Cannabinoids as Anti-Cancer Agents

Directory of Open Access Journals (Sweden)

Daniel A. Ladin

2016-10-01

Full Text Available Cancer is the second leading cause of death in the United States with 1.7 million new cases estimated to be diagnosed in 2016. This disease remains a formidable clinical challenge and represents a substantial financial burden to the US health care system. Therefore, research and development of novel therapeutics for the treatment of cancer is of high priority. Cannabinoids and their derivatives have been utilized for their medicinal and therapeutic properties throughout history. Cannabinoid activity is regulated through the endocannabinoid system, which is comprised of cannabinoid receptors, transporters, and enzymes involved in cannabinoid synthesis and breakdown. More recently, cannabinoids have gained special attention for their role in cancer development and reduction. However, many studies investigated these roles using in vitro models which may not adequately mimic tumor growth and metastasis. As such, this article aims to review study results which evaluated effects of cannabinoids from plant, synthetic and endogenous origins on cancer development in preclinical models and to examine the current standing of cannabinoids currently being tested in human cancer patients.

Harmonization in preclinical epilepsy research: A joint AES/ILAE translational initiative.

Science.gov (United States)

Galanopoulou, Aristea S; French, Jacqueline A; O'Brien, Terence; Simonato, Michele

2017-11-01

Among the priority next steps outlined during the first translational epilepsy research workshop in London, United Kingdom (2012), jointly organized by the American Epilepsy Society (AES) and the International League Against Epilepsy (ILAE), are the harmonization of research practices used in preclinical studies and the development of infrastructure that facilitates multicenter preclinical studies. The AES/ILAE Translational Task Force of the ILAE has been pursuing initiatives that advance these goals. In this supplement, we present the first reports of the working groups of the Task Force that aim to improve practices of performing rodent video-electroencephalography (vEEG) studies in experimental controls, generate systematic reviews of preclinical research data, and develop preclinical common data elements (CDEs) for epilepsy research in animals. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

Stress, Burnout and Coping Strategies in Preclinical Medical Students

Science.gov (United States)

Fares, Jawad; Al Tabosh, Hayat; Saadeddin, Zein; El Mouhayyar, Christopher; Aridi, Hussam

2016-01-01

It is acknowledged that physicians do not seek the same expert aid for themselves as they would offer their patients. In their preclinical years, medical students appear to espouse comparable behavior. To many, medicine is described as a never-ending path that places the student under heavy stress and burnout from the beginning, leaving him/her vulnerable and with insufficient coping methods. Hence, the objective of this study is to 1) explore the prevalence of stress and burnout among preclinical medical students, and 2) propose solutions to decrease stress and burnout and improve medical education in the preclinical years. A detailed scholarly research strategy using Google Scholar, Scopus, Embase, MEDLINE and PubMed was implemented to highlight key themes that are relevant to preclinical medical students’ stress and burnout. Stress varied among different samples of medical students and ranged between 20.9% and 90%. Conversely, burnout ranged between 27% and 75%. Methods that help in reducing the incidence of stress and burnout by promoting strategies that focus on personal engagement, extracurricular activities, positive reinterpretation and expression of emotion, student-led mentorship programs, evaluation systems, career counseling and life coaching should be adopted. PMID:27042604

Stress, Burnout and Coping Strategies in Preclinical Medical Students.

Science.gov (United States)

Fares, Jawad; Al Tabosh, Hayat; Saadeddin, Zein; El Mouhayyar, Christopher; Aridi, Hussam

2016-02-01

It is acknowledged that physicians do not seek the same expert aid for themselves as they would offer their patients. In their preclinical years, medical students appear to espouse comparable behavior. To many, medicine is described as a never-ending path that places the student under heavy stress and burnout from the beginning, leaving him/her vulnerable and with insufficient coping methods. Hence, the objective of this study is to 1) explore the prevalence of stress and burnout among preclinical medical students, and 2) propose solutions to decrease stress and burnout and improve medical education in the preclinical years. A detailed scholarly research strategy using Google Scholar, Scopus, Embase, MEDLINE and PubMed was implemented to highlight key themes that are relevant to preclinical medical students' stress and burnout. Stress varied among different samples of medical students and ranged between 20.9% and 90%. Conversely, burnout ranged between 27% and 75%. Methods that help in reducing the incidence of stress and burnout by promoting strategies that focus on personal engagement, extracurricular activities, positive reinterpretation and expression of emotion, student-led mentorship programs, evaluation systems, career counseling and life coaching should be adopted.

DNA cleavage enzymes for treatment of persistent viral infections: Recent advances and the pathway forward

Energy Technology Data Exchange (ETDEWEB)

Weber, Nicholas D., E-mail: nweber@fhcrc.org [Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, E5-110, Seattle, WA 98109 (United States); Department of Laboratory Medicine, University of Washington, Seattle, WA 98195 (United States); Aubert, Martine, E-mail: maubert@fhcrc.org [Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, E5-110, Seattle, WA 98109 (United States); Dang, Chung H., E-mail: cdang@fhcrc.org [Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, E5-110, Seattle, WA 98109 (United States); Stone, Daniel, E-mail: dstone2@fhcrc.org [Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, E5-110, Seattle, WA 98109 (United States); Jerome, Keith R., E-mail: kjerome@fhcrc.org [Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, E5-110, Seattle, WA 98109 (United States); Department of Laboratory Medicine, University of Washington, Seattle, WA 98195 (United States); Department of Microbiology, University of Washington, Seattle, WA 98195 (United States)

2014-04-15

Treatment for most persistent viral infections consists of palliative drug options rather than curative approaches. This is often because long-lasting viral DNA in infected cells is not affected by current antivirals, providing a source for viral persistence and reactivation. Targeting latent viral DNA itself could therefore provide a basis for novel curative strategies. DNA cleavage enzymes can be used to induce targeted mutagenesis of specific genes, including those of exogenous viruses. Although initial in vitro and even in vivo studies have been carried out using DNA cleavage enzymes targeting various viruses, many questions still remain concerning the feasibility of these strategies as they transition into preclinical research. Here, we review the most recent findings on DNA cleavage enzymes for human viral infections, consider the most relevant animal models for several human viral infections, and address issues regarding safety and enzyme delivery. Results from well-designed in vivo studies will ideally provide answers to the most urgent remaining questions, and allow continued progress toward clinical application. - Highlights: • Recent in vitro and in vivo results for DNA cleavage enzymes targeting persistent viral infections. • Analysis of the best animal models for testing enzymes for HBV, HSV, HIV and HPV. • Challenges facing in vivo delivery of therapeutic enzymes for persistent viral infections. • Safety issues to be addressed with proper animal studies.

Relationship between hydrocarbon structure and induction of P450: effects on protein levels and enzyme activities.

Science.gov (United States)

Backes, W L; Sequeira, D J; Cawley, G F; Eyer, C S

1993-12-01

1. Treatment of male rat with the small aromatic hydrocarbons, benzene, toluene, ethylbenzene, n-propylbenzene, m-xylene, and p-xylene increased several P450-dependent activities, with ethylbenzene, m-xylene, and n-propylbenzene producing the greatest response. Hydrocarbon treatment differentially affected toluene metabolism, producing a response dependent on the metabolite monitored. In untreated rats, benzyl alcohol was the major hydroxylation product of toluene metabolism, comprising > 99% of the total metabolites formed. Hydrocarbon treatment increased the overall rate of toluene metabolism by dramatically increasing the amount of aromatic hydroxylation. Ethylbenzene, n-propylbenzene and m-xylene were the most effective inducers of aromatic hydroxylation of toluene. In contrast, production of the major toluene metabolite benzyl alcohol was increased only after treatment with m-xylene. 2. P450 2B1/2B2 levels were induced by each of the hydrocarbons examined, with the magnitude of induction increasing with increasing hydrocarbon size. P450 1A1 was also induced after hydrocarbon exposure; however, the degree of induction was smaller than that observed for P450 2B1/2B2. P450 2C11 levels were suppressed after treatment with benzene, ethylbenzene and n-propylbenzene. 3. Taken together these results display two induction patterns. The first generally corresponds to changes in the P450 2B subfamily, where activities (e.g. the aromatic hydroxylations of toluene) were most effectively induced by ethylbenzene, n-propylbenzene and m-xylene. In the second, induction was observed only after m-xylene treatment, a pattern that was found when the metabolism of the substrate was catalysed by both the P450 2B subfamily and P450 2C11. Hydrocarbons that both induced P450 2B1/2B2 and suppressed P450 2C11 (such as ethylbenzene and n-propylbenzene) showed little change in activities catalysed by both isozymes (e.g. aliphatic hydroxylation of toluene, and aniline hydroxylation

Preclinical animal research on therapy dosimetry with dual isotopes

International Nuclear Information System (INIS)

Konijnenberg, Mark W.; Jong, Marion de

2011-01-01

Preclinical research into radionuclide therapies based on radiation dosimetry will enable the use of any LET-equivalent radionuclide. Radiation dose and dose rate have significant influence on dose effects in the tumour depending on its radiation sensitivity, possibilities for repair of sublethal damage, and repopulation during or after the therapy. Models for radiation response of preclinical tumour models after peptide receptor radionuclide therapy based on the linear quadratic model are presented. The accuracy of the radiation dose is very important for observation of dose-effects. Uncertainties in the radiation dose estimation arise from incomplete assay of the kinetics, low accuracy in volume measurements and absorbed dose S-values for stylized models instead of the actual animal geometry. Normal dose uncertainties in the order of 20% might easily make the difference between seeing a dose-effect or missing it altogether. This is true for the theoretical case of a homogeneous tumour type behaving in vivo in the same way as its cells do in vitro. Heterogeneity of tumours induces variations in clonogenic cell density, radiation sensitivity, repopulation capacity and repair kinetics. The influence of these aspects are analysed within the linear quadratic model for tumour response to radionuclide therapy. Preclinical tumour models tend to be less heterogenic than the clinical conditions they should represent. The results of various preclinical radionuclide therapy experiments for peptide receptor radionuclide therapy are compared to the outcome of theoretical models and the influence of increased heterogeneity is analysed when the results of preclinical research is transferred to the clinic. When the radiation dose and radiobiology of the tumour response is known well enough it may be possible to leave the current phenomenological approach in preclinical radionuclide therapy and start basing these experiments on radiation dose. Then the use of a gamma ray

Preclinical animal research on therapy dosimetry with dual isotopes

Energy Technology Data Exchange (ETDEWEB)

Konijnenberg, Mark W.; Jong, Marion de [Nuclear Medicine Department, Erasmus MC, Rotterdam (Netherlands)

2011-06-15

Preclinical research into radionuclide therapies based on radiation dosimetry will enable the use of any LET-equivalent radionuclide. Radiation dose and dose rate have significant influence on dose effects in the tumour depending on its radiation sensitivity, possibilities for repair of sublethal damage, and repopulation during or after the therapy. Models for radiation response of preclinical tumour models after peptide receptor radionuclide therapy based on the linear quadratic model are presented. The accuracy of the radiation dose is very important for observation of dose-effects. Uncertainties in the radiation dose estimation arise from incomplete assay of the kinetics, low accuracy in volume measurements and absorbed dose S-values for stylized models instead of the actual animal geometry. Normal dose uncertainties in the order of 20% might easily make the difference between seeing a dose-effect or missing it altogether. This is true for the theoretical case of a homogeneous tumour type behaving in vivo in the same way as its cells do in vitro. Heterogeneity of tumours induces variations in clonogenic cell density, radiation sensitivity, repopulation capacity and repair kinetics. The influence of these aspects are analysed within the linear quadratic model for tumour response to radionuclide therapy. Preclinical tumour models tend to be less heterogenic than the clinical conditions they should represent. The results of various preclinical radionuclide therapy experiments for peptide receptor radionuclide therapy are compared to the outcome of theoretical models and the influence of increased heterogeneity is analysed when the results of preclinical research is transferred to the clinic. When the radiation dose and radiobiology of the tumour response is known well enough it may be possible to leave the current phenomenological approach in preclinical radionuclide therapy and start basing these experiments on radiation dose. Then the use of a gamma ray

S1P prophylaxis mitigates acute hypobaric hypoxia-induced molecular, biochemical, and metabolic disturbances: A preclinical report.

Science.gov (United States)

Chawla, Sonam; Rahar, Babita; Saxena, Shweta

2016-05-01

Sphingosine-1-phosphate (S1P) is emerging to have hypoxic preconditioning potential in various preclinical studies. The study aims to evaluate the preclinical preconditioning efficacy of exogenously administered S1P against acute hypobaric hypoxia (HH)-induced pathological disturbances. Male Sprague Dawley rats (200 ± 20 g) were preconditioned with 1, 10, and 100 μg/kg body weight (b.w.) S1P (i.v.) for three consecutive days. On the third day, S1P preconditioned animals, along with hypoxia control animals, were exposed to HH equivalent to 7,620 m (280 mm Hg) for 6 h. Postexposure status of cardiac energy production, circulatory vasoactive mediators, pulmonary and cerebral oxidative damage, and inflammation were assessed. HH exposure led to cardiac energy deficit indicated by low ATP levels and pronounced AMPK activation levels, raised circulatory levels of brain natriuretic peptide and endothelin-1 with respect to total nitrate (NOx), redox imbalance, inflammation, and alterations in NOx levels in the pulmonary and cerebral tissues. These pathological precursors have been routinely reported to be coincident with high-altitude diseases. Preconditioning with S1P, especially 1 µg/kg b.w. dose, was seen to reverse the manifestation of these pathological disturbances. The protective efficacy could be attributed, at least in part, to enhanced activity of cardioprotective protein kinase C and activation of small GTPase Rac1, which led to further induction of hypoxia-adaptive molecular mediators: hypoxia-inducible factor (HIF)-1α and Hsp70. This is a first such report, to the best of our knowledge, elucidating the mechanism of exogenous S1P-mediated HIF-1α/Hsp70 induction. Conclusively, systemic preconditioning with 1 μg/kg b.w. S1P in rats protects against acute HH-induced pathological disturbances. © 2016 IUBMB Life 68(5):365-375, 2016. © 2016 International Union of Biochemistry and Molecular Biology.

Characterization of novel preclinical dose distributions for micro irradiator

International Nuclear Information System (INIS)

Kodra, J; Miles, D; Yoon, S W; Kirsch, D G; Oldham, M

2017-01-01

This work explores and demonstrates the feasibility of utilizing new 3D printing techniques to implement advanced micro radiation therapy for pre-clinical small animal studies. 3D printed blocks and compensators were designed and printed from a strong x-ray attenuating material at sub-millimeter resolution. These techniques enable a powerful range of new preclinical treatment capabilities including grid therapy, lattice therapy, and IMRT treatment. At small scales, verification of these treatments is exceptionally challenging, and high resolution 3D dosimetry (0.5mm 3 ) is an essential capability to characterize and verify these capabilities, Here, investigate the 2D and 3D dosimetry of several novel pre-clinical treatments using a combination of EBT film and Presage/optical-CT 3D dosimetry in rodent-morphic dosimeters. (paper)

Characterization of novel preclinical dose distributions for micro irradiator

Science.gov (United States)

Kodra, J.; Miles, D.; Yoon, S. W.; Kirsch, D. G.; Oldham, M.

2017-05-01

This work explores and demonstrates the feasibility of utilizing new 3D printing techniques to implement advanced micro radiation therapy for pre-clinical small animal studies. 3D printed blocks and compensators were designed and printed from a strong x-ray attenuating material at sub-millimeter resolution. These techniques enable a powerful range of new preclinical treatment capabilities including grid therapy, lattice therapy, and IMRT treatment. At small scales, verification of these treatments is exceptionally challenging, and high resolution 3D dosimetry (0.5mm3) is an essential capability to characterize and verify these capabilities, Here, investigate the 2D and 3D dosimetry of several novel pre-clinical treatments using a combination of EBT film and Presage/optical-CT 3D dosimetry in rodent-morphic dosimeters.

The Devil Is in the Details: Incomplete Reporting in Preclinical Animal Research.

Directory of Open Access Journals (Sweden)

Marc T Avey

Full Text Available Incomplete reporting of study methods and results has become a focal point for failures in the reproducibility and translation of findings from preclinical research. Here we demonstrate that incomplete reporting of preclinical research is not limited to a few elements of research design, but rather is a broader problem that extends to the reporting of the methods and results. We evaluated 47 preclinical research studies from a systematic review of acute lung injury that use mesenchymal stem cells (MSCs as a treatment. We operationalized the ARRIVE (Animal Research: Reporting of In Vivo Experiments reporting guidelines for pre-clinical studies into 109 discrete reporting sub-items and extracted 5,123 data elements. Overall, studies reported less than half (47% of all sub-items (median 51 items; range 37-64. Across all studies, the Methods Section reported less than half (45% and the Results Section reported less than a third (29%. There was no association between journal impact factor and completeness of reporting, which suggests that incomplete reporting of preclinical research occurs across all journals regardless of their perceived prestige. Incomplete reporting of methods and results will impede attempts to replicate research findings and maximize the value of preclinical studies.

INDUCTION OF ENZYME COCKTAILS BY LOW COST CARBON SOURCES FOR PRODUCTION OF MONOSACCHARIDE-RICH SYRUPS FROM PLANT MATERIALS

Directory of Open Access Journals (Sweden)

Caroline T. Gilleran

2010-05-01

Full Text Available The production of cellulases, hemicellulases, and starch-degrading enzymes by the thermophilic aerobic fungus Talaromyces emersonii under liquid state culture on various food wastes was investigated. A comprehensive enzyme screening was conducted, which resulted in the identification of spent tea leaves as a potential substrate for hydrolytic enzyme production. The potent, polysaccharide-degrading enzyme-rich cocktail produced when tea leaves were utilised as sole carbon source was analysed at a protein and mRNA level and shown to exhibit high level production of key cellulose and hemicellulose degrading enzymes. As presented in this paper, the crude enzyme preparation produced after 120 h growth of Talaromyces emersonii on used tea leaves is capable of hydrolysing other lignocellulosic materials into their component monosaccharides, generating high value sugar syrups with a host of industrial applications including conversion to fuels and chemicals.

Antioxidant enzymes activity in embryogenic and non-embryogenic tissues in Sugarcane

International Nuclear Information System (INIS)

Marina Medeiros de Araujo Silva; Ulisses, Claudia; Lacerda E Medeiros, Maria Jaislanny; Cavalcante Granja, Manuela Maria; Willadino, Lilia; Camara, Terezinha

2014-01-01

The objective of this work was to induce direct somatic embryogenesis from segments of immature leaves of the RB872552 variety of sugarcane and to correlate this morphogenic event with oxidative stress. Two previously described protocols were utilized for the induction of somatic embryogenesis in sugarcane with different supplementations of the culture medium and different incubation conditions. For the conversion of embryos into plants was used ms medium without phytoregulators. Histological analyses and activity of antioxidant enzymes were also conducted for the embryogenic and non-embryogenic tissues. The formation of somatic embryos was obtained in 81 % of the explants with the combination of regulators 2,4-D (2,4-dichlorophenoxyacetic acid)and BAP (6-benzylaminopurine) when incubated under 16 h photoperiod. With regards to the antioxidant enzymes, there was increased activity of peroxidase and an increase in the soluble protein content in embryogenic tissues, whereas lower activities of polyphenol oxidase and catalase appeared in these tissues compared to nonembryogenic tissues. It could be inferred that oxidative stress plays an important role in the induction of somatic embryogenesis in sugarcane.

Extracurricular activities associated with stress and burnout in preclinical medical students

Directory of Open Access Journals (Sweden)

Jawad Fares

2016-09-01

Full Text Available This study aims to assess the prevalence of stress and burnout among preclinical medical students in a private university in Beirut, Lebanon, and evaluate the association between extracurricular involvement and stress and burnout relief in preclinical medical students. A cross-sectional survey was conducted on a random sample of 165 preclinical medical students. Distress level was measured using the 12-item General Health Questionnaire (GHQ-12 while that of burnout was measured through the Maslach Burnout Inventory-Student Survey (MBI-SS. The MBI-SS assesses three interrelated dimensions: emotional exhaustion, cynicism, and academic efficacy. Extracurricular activities were divided into four categories: physical exercise, music, reading, and social activities. All selected participants responded. A substantial proportion of preclinical medical students suffered from stress (62% and burnout (75%. Bivariate and multivariate regression analyses revealed that being a female or a 1st year medical student correlated with higher stress and burnout. Music-related activities were correlated with lower burnout. Social activities or living with parents were associated with lower academic efficacy. The high stress and burnout levels call for action. Addressing the studying conditions and attending to the psychological wellbeing of preclinical medical students are recommendations made in the study.

Extracurricular activities associated with stress and burnout in preclinical medical students.

Science.gov (United States)

Fares, Jawad; Saadeddin, Zein; Al Tabosh, Hayat; Aridi, Hussam; El Mouhayyar, Christopher; Koleilat, Mohamad Karim; Chaaya, Monique; El Asmar, Khalil

2016-09-01

This study aims to assess the prevalence of stress and burnout among preclinical medical students in a private university in Beirut, Lebanon, and evaluate the association between extracurricular involvement and stress and burnout relief in preclinical medical students. A cross-sectional survey was conducted on a random sample of 165 preclinical medical students. Distress level was measured using the 12-item General Health Questionnaire (GHQ-12) while that of burnout was measured through the Maslach Burnout Inventory-Student Survey (MBI-SS). The MBI-SS assesses three interrelated dimensions: emotional exhaustion, cynicism, and academic efficacy. Extracurricular activities were divided into four categories: physical exercise, music, reading, and social activities. All selected participants responded. A substantial proportion of preclinical medical students suffered from stress (62%) and burnout (75%). Bivariate and multivariate regression analyses revealed that being a female or a 1st year medical student correlated with higher stress and burnout. Music-related activities were correlated with lower burnout. Social activities or living with parents were associated with lower academic efficacy. The high stress and burnout levels call for action. Addressing the studying conditions and attending to the psychological wellbeing of preclinical medical students are recommendations made in the study. Copyright © 2015 Ministry of Health, Saudi Arabia. Published by Elsevier Ltd. All rights reserved.

Preclinical experimental stress studies: protocols, assessment and comparison.

Science.gov (United States)

Bali, Anjana; Jaggi, Amteshwar Singh

2015-01-05

Stress is a state of threatened homeostasis during which a variety of adaptive processes are activated to produce physiological and behavioral changes. Preclinical models are pivotal for understanding these physiological or pathophysiological changes in the body in response to stress. Furthermore, these models are also important for the development of novel pharmacological agents for stress management. The well described preclinical stress models include immobilization, restraint, electric foot shock and social isolation stress. Stress assessment in animals is done at the behavioral level using open field, social interaction, hole board test; at the biochemical level by measuring plasma corticosterone and ACTH; at the physiological level by measuring food intake, body weight, adrenal gland weight and gastric ulceration. Furthermore the comparison between different stressors including electric foot shock, immobilization and cold stressor is described in terms of intensity, hormonal release, protein changes in brain, adaptation and sleep pattern. This present review describes these preclinical stress protocols, and stress assessment at different levels. Copyright © 2014 Elsevier B.V. All rights reserved.

Screening of Enzyme Biomarker for Nanotoxicity of Zinc Oxide in OREOCHROMIS MOSSAMBICUS

Science.gov (United States)

Subramanian, Periasamy; Bupesh, Giridharan

2011-06-01

Experiments were conducted to determine the effects of Zinc oxide (ZnO) nanoparticles (NPs) on fish models. Oreochromis mossambicus was orally administered with ZnO NPs (50-100 nm) once and its effects at five different concentrations (60 ppm-100 ppm) were observed for 12 days. Enzymatic assays were performed at every three days interval in the vital tissues of liver, gill, muscle and kidney. The defense enzymes, ethoxyresorufin O-deethylase (EROD) and glutathione S transferase (GST) exerted a dose dependent elevation up to 6 days. This hike then declines in higher concentrations and extended duration. Whereas the tissue damaging enzymes, glutamate oxaloacetic transaminase (GOT), glutamate pyruvic transaminase (GPT) and alkaline phosphatase (ALP) as well as the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) exhibited a dose and duration dependent increase until the end of the experiment. Among these enzymes, the antioxidant enzymes response to ZnO NP toxicity on fish showed notable continuous induction. This study demonstrates that antioxidant enzymes responses in O. mossambicus could be used as a biomarker for the early detection of nanotoxicity.

Blarina brevicauda as a biological monitor of polychlorinated biphenyls: evaluation of hepatic cytochrome P450 induction.

Science.gov (United States)

Russell, Julie S; Halbrook, Richard S; Woolf, Alan; French, John B; Melancon, Mark J

2004-08-01

We assessed the value of short-tailed shrews (Blarina brevicauda) as a possible biomonitor for polychlorinated biphenyl pollution through measurement of the induction of hepatic cytochrome P450 and associated enzyme activities. First, we checked the inducibility of four monooxygenases (benzyloxyresorufin-O-dealkylase [BROD], ethoxyresorufin-O-dealkylase [EROD], methoxyresorufin-O-dealkylase [MROD], and pentoxyresorufin-O-dealkylase [PROD]) by measuring the activity of these enzymes in hepatic microsomes prepared from shrews injected with beta-naphthoflavone (betaNF) or phenobarbital (PB), typical inducers of cytochrome P4501A (CYP1A) and CYP2B enzyme families, respectively. Enzyme activity was induced in shrews that received betaNF but not in shrews that received PB; PROD was not induced by either exposure. Later, shrews were exposed to a mixture of polychlorinated biphenyls (PCBs) (Aroclor 1242:1254, in 1:2 ratio) at 0.6, 9.6, and 150 ppm in food, for 31 d. Induction in these shrews was measured by specific enzyme activity (BROD, EROD, and MROD) in hepatic microsomes, by western blotting of solubilized microsomes against antibodies to CYP1A or CYP2B, and by duration of sodium pentobarbital-induced sleep. These three CYP enzymes were induced in shrews by PCBs at similar levels of exposure as in cotton rat (Sigmodon hispidus). Neither sleep time nor the amount of CYP2B family protein were affected by PCB exposure. Blarina brevicauda can be a useful biomonitor of PCBs that induce CYP1A, especially in habitats where they are the abundant small mammal.

A novel marker for assessment of liver matrix remodeling: An enzyme-linked immunosorbent assay (ELISA) detecting a MMP generated type I collagen neo-epitope (C1M)

DEFF Research Database (Denmark)

Leeming, Diana Julie; He, Y.; Veidal, S. S.

2011-01-01

A competitive enzyme-linked immunosorbent assay (ELISA) for detection of a type I collagen fragment generated by matrix metalloproteinases (MMP) -2, -9 and -13, was developed (CO1-764 or C1M). The biomarker was evaluated in two preclinical rat models of liver fibrosis: bile duct ligation (BDL) an...

Standards and Methodological Rigor in Pulmonary Arterial Hypertension Preclinical and Translational Research.

Science.gov (United States)

Provencher, Steeve; Archer, Stephen L; Ramirez, F Daniel; Hibbert, Benjamin; Paulin, Roxane; Boucherat, Olivier; Lacasse, Yves; Bonnet, Sébastien

2018-03-30

Despite advances in our understanding of the pathophysiology and the management of pulmonary arterial hypertension (PAH), significant therapeutic gaps remain for this devastating disease. Yet, few innovative therapies beyond the traditional pathways of endothelial dysfunction have reached clinical trial phases in PAH. Although there are inherent limitations of the currently available models of PAH, the leaky pipeline of innovative therapies relates, in part, to flawed preclinical research methodology, including lack of rigour in trial design, incomplete invasive hemodynamic assessment, and lack of careful translational studies that replicate randomized controlled trials in humans with attention to adverse effects and benefits. Rigorous methodology should include the use of prespecified eligibility criteria, sample sizes that permit valid statistical analysis, randomization, blinded assessment of standardized outcomes, and transparent reporting of results. Better design and implementation of preclinical studies can minimize inherent flaws in the models of PAH, reduce the risk of bias, and enhance external validity and our ability to distinguish truly promising therapies form many false-positive or overstated leads. Ideally, preclinical studies should use advanced imaging, study several preclinical pulmonary hypertension models, or correlate rodent and human findings and consider the fate of the right ventricle, which is the major determinant of prognosis in human PAH. Although these principles are widely endorsed, empirical evidence suggests that such rigor is often lacking in pulmonary hypertension preclinical research. The present article discusses the pitfalls in the design of preclinical pulmonary hypertension trials and discusses opportunities to create preclinical trials with improved predictive value in guiding early-phase drug development in patients with PAH, which will need support not only from researchers, peer reviewers, and editors but also from

Survival of Bemisia tabaci and activity of plant defense-related enzymes in genotypes of Capsicum annuum L.

Directory of Open Access Journals (Sweden)

Luis Latournerie-Moreno

2015-03-01

Full Text Available The whitefly Bemisia tabaci (Gennadius, 1889 is a major plant pest of horticultural crops from the families Solanaceae, Fabaceae and Cucurbitaceae in Neotropical areas. The exploration of host plant resistance and their biochemical mechanisms offers an excellent alternative to better understand factors affecting the interaction between phytophagous insect and host plant. We evaluated the survival of B. tabaci in landrace genotypes of Capsicum annuum L., and the activity of plant defense-related enzymes (chitinase, polyphenoloxidase, and peroxidase. The landrace genotypes Amaxito, Tabaquero, and Simojovel showed resistance to B. tabaci, as we observed more than 50% nymphal mortality, while in the commercial susceptible genotype Jalapeño mortality of B. tabaci nymphs was not higher than 20%. The activities of plant defense-related enzymes were significantly different among pepper genotypes (P < 0.05. Basal activities of chitinase, polyphenoloxidase and peroxidase were significantly lower or equal in landrace genotypes than that of the commercial genotype Jalapeño. The activity of plant enzymes was differential among pepper genotypes (P < 0.05. For example, the activity of chitinase enzyme generally was higher in non-infested plants with B. tabaci than those infested. Instead polyphenoloxidase ('Amaxito' and 'Simojovel' and peroxidase enzymes activities ('Tabaquero' increased in infested plants (P < 0.05. We conclude that basal activities of plant defense-related enzymes could be act through other mechanism plant induction, since plant defense-related enzymes showed a different induction response to B. tabaci. We underlined the role of polyphenoloxidase as plant defense in the pepper genotype Simojovel related to B. tabaci.

Restoflex--a revolutionary change in preclinical practice for restorative dentistry and endodontics.

Science.gov (United States)

Jain, Shweta; Khaiser, Imran M; Thakur, Sophia; Jain, Shikha

2014-05-01

Preclinical exercises are very important for the dental students in order to master various dental techniques. The objective of this article is to introduce a new preclinical working model named Restoflex. It is especially designed for the students to carry out various restorative and endodontic procedures in an environment that closely simulate clinical situations. This will help them to provide a smooth transition from preclinical environment to the clinical one. It would also mean an increased confidence level and the efficiency with which the students would deal with their cases.

Neurotoxicity in Preclinical Models of Occupational Exposure to Organophosphorus Compounds

Science.gov (United States)

Voorhees, Jaymie R.; Rohlman, Diane S.; Lein, Pamela J.; Pieper, Andrew A.

2017-01-01

Organophosphorus (OPs) compounds are widely used as insecticides, plasticizers, and fuel additives. These compounds potently inhibit acetylcholinesterase (AChE), the enzyme that inactivates acetylcholine at neuronal synapses, and acute exposure to high OP levels can cause cholinergic crisis in humans and animals. Evidence further suggests that repeated exposure to lower OP levels insufficient to cause cholinergic crisis, frequently encountered in the occupational setting, also pose serious risks to people. For example, multiple epidemiological studies have identified associations between occupational OP exposure and neurodegenerative disease, psychiatric illness, and sensorimotor deficits. Rigorous scientific investigation of the basic science mechanisms underlying these epidemiological findings requires valid preclinical models in which tightly-regulated exposure paradigms can be correlated with neurotoxicity. Here, we review the experimental models of occupational OP exposure currently used in the field. We found that animal studies simulating occupational OP exposures do indeed show evidence of neurotoxicity, and that utilization of these models is helping illuminate the mechanisms underlying OP-induced neurological sequelae. Still, further work is necessary to evaluate exposure levels, protection methods, and treatment strategies, which taken together could serve to modify guidelines for improving workplace conditions globally. PMID:28149268

Differential retinoic acid inhibition of ornithine decarboxylase induction by 12-O-tetradecanoylphorbol-13-acetate and by germicidal ultraviolet light

International Nuclear Information System (INIS)

Lichti, U.; Patterson, E.; Hennings, H.; Yuspa, S.H.

1981-01-01

Several retinoids including retinoic acid effectively inhibit phorbol ester-mediated tumor promotion and ornithine decarboxylase (ODC) induction in mouse epidermis. To understand better the possible cellular site of action of retinoids, the inhibitory action of retinoic acid on the induction of ODC was compared for two distinctly different inducers, namely, 12-O-tetradecanoylphorbol-13-acetate (TPA) and germicidal ultraviolet light (uv), in primary mouse epidermal cell cultures. It was found that the induction of ODC by TPA is almost completely prevented by retinoic acid while the induction by uv is only moderately inhibited. The differential inhibition of enzyme induction cannot be accounted for by selective retinoid inhibition of DNA, RNA, or protein synthesis either alone or in concert with TPA or uv. These agents possibly act at transcription or translation, both of which are required for ODC induction by TPA or uv

Kinetic modeling in pre-clinical positron emission tomography

Energy Technology Data Exchange (ETDEWEB)

Kuntner, Claudia [AIT Austrian Institute of Technology GmbH, Seibersdorf (Austria). Biomedical Systems, Health and Environment Dept.

2014-07-01

Pre-clinical positron emission tomography (PET) has evolved in the last few years from pure visualization of radiotracer uptake and distribution towards quantification of the physiological parameters. For reliable and reproducible quantification the kinetic modeling methods used to obtain relevant parameters of radiotracer tissue interaction are important. Here we present different kinetic modeling techniques with a focus on compartmental models including plasma input models and reference tissue input models. The experimental challenges of deriving the plasma input function in rodents and the effect of anesthesia are discussed. Finally, in vivo application of kinetic modeling in various areas of pre-clinical research is presented and compared to human data.

Anti-Correlated Cerebrospinal Fluid Biomarker Trajectories in Preclinical Alzheimer's Disease.

Science.gov (United States)

Gomar, Jesus J; Conejero-Goldberg, Concepcion; Davies, Peter; Goldberg, Terry E

2016-01-01

The earliest stage of preclinical Alzheimer's disease (AD) is defined by low levels of cerebrospinal fluid (CSF) amyloid-β (Aβ42). However, covariance in longitudinal dynamic change of Aβ42 and tau in incipient preclinical AD is poorly understood. To examine dynamic interrelationships between Aβ42 and tau in preclinical AD. We followed 47 cognitively intact participants (CI) with available CSF data over four years in ADNI. Based on longitudinal Aβ42 levels in CSF, CI were classified into three groups: 1) Aβ42 stable with normal levels of Aβ42 over time (n = 15); 2) Aβ42 declining with normal Aβ42 levels at baseline but showing decline over time (n = 14); and 3) Aβ42 levels consistently abnormal (n = 18). In the Aβ42 declining group, suggestive of incipient preclinical AD, CSF phosphorylated tau (p-tau) showed a similar longitudinal pattern of increasing abnormality over time (p = 0.0001). Correlation between longitudinal slopes of Aβ42 and p-tau confirmed that both trajectories were anti-correlated (rho = -0.60; p = 0.02). Regression analysis showed that Aβ42 slope (decreasing Aβ42) predicted p-tau slope (increasing p-tau) (R2 = 0.47, p = 0.03). Atrophy in the hippocampus was predicted by the interaction of Aβ42 and p-tau slopes (p anti-correlated trajectory, i.e., as Aβ42 declined, p-tau increased, and thus was suggestive of strong temporal coincidence. Rapid pathogenic cross-talk between Aβ42 and p-tau thus may be evident in very early stages of preclinical AD.

Rigor or mortis: best practices for preclinical research in neuroscience.

Science.gov (United States)

Steward, Oswald; Balice-Gordon, Rita

2014-11-05

Numerous recent reports document a lack of reproducibility of preclinical studies, raising concerns about potential lack of rigor. Examples of lack of rigor have been extensively documented and proposals for practices to improve rigor are appearing. Here, we discuss some of the details and implications of previously proposed best practices and consider some new ones, focusing on preclinical studies relevant to human neurological and psychiatric disorders. Copyright © 2014 Elsevier Inc. All rights reserved.

[The participation of ethanol in induction of carbohydrates metabolism disturbances].

Science.gov (United States)

Orywal, Karolina; Jelski, Wojciech; Szmitkowski, Maciej

2009-07-01

Alcohol and products of its metabolism lead to impairment of many organs functions, what cause systemic and local carbohydrates metabolism disturbances. Abusing of alcohol induces changes in pancreatic digestive enzymes secretion, what contributes to development of chronic alcoholic pancreatitis. Alcohol can cause secondary diabetes, what is result of pancreatic beta-cells damage and is a risk factor for type 2 diabetes. Alcohol cause liver cells degeneration and induction of many metabolic disturbances especially carbohydrates.

VITAMIN AND THYROID STATUS IN ARCTIC GRAYLING (THYMALLUS ARCTICUS) EXPOSED TO DOSES OF 3, 3', 4, 4'-TETRACHLOROBIPHENYL THAT INDUCE THE PHASE I ENZYME SYSTEM

Science.gov (United States)

Induction of phase I biotransformation enzymes is recognized as a hallmark response in fish exposed to coplanar PCBs. Depletions of vitamins A and E and disrupted thyroid hormone and glandular structure secondary to this induction have not yet been examined in an arctic fish spec...

Automatic design of decision-tree induction algorithms tailored to flexible-receptor docking data.

Science.gov (United States)

Barros, Rodrigo C; Winck, Ana T; Machado, Karina S; Basgalupp, Márcio P; de Carvalho, André C P L F; Ruiz, Duncan D; de Souza, Osmar Norberto

2012-11-21

This paper addresses the prediction of the free energy of binding of a drug candidate with enzyme InhA associated with Mycobacterium tuberculosis. This problem is found within rational drug design, where interactions between drug candidates and target proteins are verified through molecular docking simulations. In this application, it is important not only to correctly predict the free energy of binding, but also to provide a comprehensible model that could be validated by a domain specialist. Decision-tree induction algorithms have been successfully used in drug-design related applications, specially considering that decision trees are simple to understand, interpret, and validate. There are several decision-tree induction algorithms available for general-use, but each one has a bias that makes it more suitable for a particular data distribution. In this article, we propose and investigate the automatic design of decision-tree induction algorithms tailored to particular drug-enzyme binding data sets. We investigate the performance of our new method for evaluating binding conformations of different drug candidates to InhA, and we analyze our findings with respect to decision tree accuracy, comprehensibility, and biological relevance. The empirical analysis indicates that our method is capable of automatically generating decision-tree induction algorithms that significantly outperform the traditional C4.5 algorithm with respect to both accuracy and comprehensibility. In addition, we provide the biological interpretation of the rules generated by our approach, reinforcing the importance of comprehensible predictive models in this particular bioinformatics application. We conclude that automatically designing a decision-tree algorithm tailored to molecular docking data is a promising alternative for the prediction of the free energy from the binding of a drug candidate with a flexible-receptor.

Tissue Engineering of the Urethra: A Systematic Review and Meta-analysis of Preclinical and Clinical Studies.

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Versteegden, Luuk R M; de Jonge, Paul K J D; IntHout, Joanna; van Kuppevelt, Toin H; Oosterwijk, Egbert; Feitz, Wout F J; de Vries, Rob B M; Daamen, Willeke F

2017-10-01

Urethra repair by tissue engineering has been extensively studied in laboratory animals and patients, but is not routinely used in clinical practice. To systematically investigate preclinical and clinical evidence of the efficacy of tissue engineering for urethra repair in order to stimulate translation of preclinical studies to the clinic. A systematic search strategy was applied in PubMed and EMBASE. Studies were independently screened for relevance by two reviewers, resulting in 80 preclinical and 23 clinical studies of which 63 and 13 were selected for meta-analysis to assess side effects, functionality, and study completion. Analyses for preclinical and clinical studies were performed separately. Full circumferential and inlay procedures were assessed independently. Evaluated parameters included seeding of cells and type of biomaterial. Meta-analysis revealed that cell seeding significantly reduced the probability of encountering side effects in preclinical studies. Remarkably though, cells were only sparsely used in the clinic (4/23 studies) and showed no significant reduction of side effects. ln 21 out of 23 clinical studies, decellularized templates were used, while in preclinical studies other biomaterials showed promising outcomes as well. No direct comparison to current clinical practice could be made due to the limited number of randomized controlled studies. Due to a lack of controlled (pre)clinical studies, the efficacy of tissue engineering for urethra repair could not be determined. Meta-analysis outcome measures were similar to current treatment options described in literature. Surprisingly, it appeared that favorable preclinical results, that is inclusion of cells, were not translated to the clinic. Improved (pre)clinical study designs may enhance clinical translation. We reviewed all available literature on urethral tissue engineering to assess the efficacy in preclinical and clinical studies. We show that improvements to (pre)clinical study

Marker for the pre-clinical development of bone substitute materials

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de Wild Michael

2017-09-01

Full Text Available Thin mechanically stable Ti-cages have been developed for the in-vivo application as X-ray and histology markers for the optimized evaluation of pre-clinical performance of bone graft materials. A metallic frame defines the region of interest during histological investigations and supports the identification of the defect site. This standardization of the procedure enhances the quality of pre-clinical experiments. Different models of thin metallic frameworks were designed and produced out of titanium by additive manufacturing (Selective Laser Melting. The productibility, the mechanical stability, the handling and suitability of several frame geometries were tested during surgery in artificial and in ex-vivo bone before a series of cages was preclinically investigated in the female Göttingen minipigs model. With our novel approach, a flexible process was established that can be adapted to the requirements of any specific animal model and bone graft testing.

Effects of naturally occurring coumarins on hepatic drug-metabolizing enzymes inmice

International Nuclear Information System (INIS)

Kleiner, Heather E.; Xia, Xiaojun; Sonoda, Junichiro; Zhang, Jun; Pontius, Elizabeth; Abey, Jane; Evans, Ronald M.; Moore, David D.; DiGiovanni, John

2008-01-01

Cytochromes P450 (P450s) and glutathione S-transferases (GSTs) constitute two important enzyme families involved in carcinogen metabolism. Generally, P450s play activation or detoxifying roles while GSTs act primarily as detoxifying enzymes. We previously demonstrated that oral administration of the linear furanocoumarins, isopimpinellin and imperatorin, modulated P450 and GST activities in various tissues of mice. The purpose of the present study was to compare a broader range of naturally occurring coumarins (simple coumarins, and furanocoumarins of the linear and angular type) for their abilities to modulate hepatic drug-metabolizing enzymes when administered orally to mice. We now report that all of the different coumarins tested (coumarin, limettin, auraptene, angelicin, bergamottin, imperatorin and isopimpinellin) induced hepatic GST activities, whereas the linear furanocoumarins possessed the greatest abilities to induce hepatic P450 activities, in particular P450 2B and 3A. In both cases, this corresponded to an increase in protein expression of the enzymes. Induction of P4502B10, 3A11, and 2C9 by xenobiotics often is a result of activation of the pregnane X receptor (PXR) and/or constitutive androstane receptor (CAR). Using a pregnane X receptor reporter system, our results demonstrated that isopimpinellin activated both PXR and its human ortholog SXR by recruiting coactivator SRC-1 in transfected cells. In CAR transfection assays, isopimpinellin counteracted the inhibitory effect of androstanol on full-length mCAR, a Gal4-mCAR ligand-binding domain fusion, and restored coactivator binding. Orally administered isopimpinellin induced hepatic mRNA expression of Cyp2b10, Cyp3a11, and GSTa in CAR(+/+) wild-type mice. In contrast, the induction of Cyp2b10 mRNA by isopimpinellin was attenuated in the CAR(-/-) mice, suggesting that isopimpinellin induces Cyp2b10 via the CAR receptor. Overall, the current data indicate that naturally occurring coumarins have

Induction of homologous recombination in Saccharomyces cerevisiae.

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Simon, J R; Moore, P D

1988-09-01

We have investigated the effects of UV irradiation of Saccharomyces cerevisiae in order to distinguish whether UV-induced recombination results from the induction of enzymes required for homologous recombination, or the production of substrate sites for recombination containing regions of DNA damage. We utilized split-dose experiments to investigate the induction of proteins required for survival, gene conversion, and mutation in a diploid strain of S. cerevisiae. We demonstrate that inducing doses of UV irradiation followed by a 6 h period of incubation render the cells resistant to challenge doses of UV irradiation. The effects of inducing and challenge doses of UV irradiation upon interchromosomal gene conversion and mutation are strictly additive. Using the yeast URA3 gene cloned in non-replicating single- and double-stranded plasmid vectors that integrate into chromosomal genes upon transformation, we show that UV irradiation of haploid yeast cells and homologous plasmid DNA sequences each stimulate homologous recombination approximately two-fold, and that these effects are additive. Non-specific DNA damage has little effect on the stimulation of homologous recombination, as shown by studies in which UV-irradiated heterologous DNA was included in transformation/recombination experiments. We further demonstrate that the effect of competing single- and double-stranded heterologous DNA sequences differs in UV-irradiated and unirradiated cells, suggesting an induction of recombinational machinery in UV-irradiated S. cerevisiae cells.

[Impact of microdose clinical trials in the preclinical stage].

Science.gov (United States)

Kim, Soonih

2014-01-01

A microdose clinical trial may be useful as a safe early-phase exploratory study using doses as low as 100 μg or less for determination of the disposition of a candidate compound in humans in a short period of time. This may increase confidence in candidate compounds, especially those for which it is difficult to predict disposition based on the results of in vitro or preclinical studies. In this study, we examined microdose trials performed in the preclinical stage for two first-in-class compounds with a new mechanism of action. These compounds showed species difference in first pass metabolism in the digestive tract and liver, causing uncertainty in prediction of disposition in humans. For this reason, first-in-human microdose clinical trials were performed. The results showed that the two compounds had effective blood concentrations after oral administration at a dose of 100 mg qd. Administration of an extremely small dose of one (14)C-labeled compound permitted identification of major metabolites. No toxic metabolites were detected. The preclinical toxic dose was determined based on prediction of blood exposure at the estimated maximum clinical dose. For the other candidate compound, the findings of the microdose trial indicated a high bioavailability after oral administration and low hepatic clearance after intravenous administration. These results suggested only a small risk of a change in disposition in patients with hepatic disorder. The data obtained for the two compounds suggest that microdose clinical trials can be useful for improving the process of candidate selection in the preclinical stage.

Induction of UMUC+ gene expression in Escherichia coli irradiated by near ultraviolet light

International Nuclear Information System (INIS)

Sato, N.; Ohnishi, T.; Tano, K.; Nozu, K.; Yamamoto, K.

1985-01-01

The induction of umu + gene expression caused by irradiation with near ultraviolet light (BLB; black light blue) was studied in Escherichia coli K-12 strains with special reference to the effects of SOS repair deficiencies. The umuC + gene expression was measured as the enzymic activity of β-galactosidase which is regulated by the promoter of the umuC + operon carried in a plasmid DNA carrying a promoter of umuC + operon, a umuD + gene and a umuC + -lacZ + gene fusion. A high induction of the umuC + gene expression was observed in the uvrA cells in the case of BLB or UV irradiation as compared with the parental wild-type cells. Caffeine inhibited the induction of the umuC + gene expression due to BLB or UV irradiation in both strains. There was very little induction in lexA and recA mutants. In contrast with UV irradiation, there was no killing of cells by BLB irradiation in any strain (wild, uvrA, lexA and recA). Possible implications of the experimental results were discussed. (author)

Variations of some parameters of enzyme induction in chemical workers

Energy Technology Data Exchange (ETDEWEB)

Dolara, P. (Univ. of Florence, Italy); Lodovici, M.; Buffoni, F.; Buiatti, E.; Baccetti, S.; Ciofini, O.; Bavazzano, P.; Barchielli, S.; Vannucci, V.

1982-01-01

Several parameters related to mono-oxygenase activity were followed in a population of chemical workers and controls. Workers exposed to toluene and xylene had a significant increase of urinary glucaric acid, that was correlated with hippuric acid excretion. On the other hand, workers exposed to pigments showed a marked increase of antipyrine half-life. A dose-related decrease of liver N-demethylase was induced in rats by the administration of a mixture of three of the pigments in use in the plant. Serum gamma-glutamyltranspeptidase was decreased in the workers exposed to pigments, but this variation was not statistically significant. The exposure to different chemicals in the workplace seemed to induce a complicated variation of mono-oxygenase levels, some enzyme being inhibited and others induced in the same group of workers. The sensitivity of these workers to toxic effects of chemicals, carcinogenic compounds and drugs seems to differ markedly from the control population.

Glucoraphanin, the bioprecursor of the widely extolled chemopreventive agent sulforaphane found in broccoli, induces Phase-I xenobiotic metabolizing enzymes and increases free radical generation in rat liver

Energy Technology Data Exchange (ETDEWEB)

Perocco, Paolo [Department of Experimental Pathology, Cancerology Section, viale Filopanti 22, I-40126, University of Bologna, Bologna (Italy); Bronzetti, Giorgio [Institute of Biology and Agricultural Biotechnology - CNR Research Area, via Moruzzi, I-56124 Pisa (Italy); Canistro, Donatella; Sapone, Andrea; Affatato, Alessandra; Pozzetti, Laura; Broccoli, Massimiliano [Department of Pharmacology, Molecular Toxicology Unit, via Irnerio 48, I-40126, University of Bologna, Bologna (Italy); Valgimigli, Luca [Department of Organic Chemistry ' A. Mangini' , Viale Risorgimento 4, I-40127, Alma-Mater Studiorum, University of Bologna, Bologna (Italy); Pedulli, Gian Franco [Department of Organic Chemistry ' A. Mangini' , Viale Risorgimento 4, I-40127, Alma-Mater Studiorum, University of Bologna, Bologna (Italy); Iori, Renato [C.R.A - Research Institute for Industrial Crops, via di Corticella 133, I-40129 Bologna (Italy); Barillari, Jessica [Institute of Biology and Agricultural Biotechnology - CNR Research Area, via Moruzzi, I-56124 Pisa (Italy)]|[C.R.A - Research Institute for Industrial Crops, via di Corticella 133, I-40129 Bologna (Italy); Sblendorio, Valeriana [Department of Pharmacology, Molecular Toxicology Unit, via Irnerio 48, I-40126, University of Bologna, Bologna (Italy); Legator, Marvin S. [Department of Preventive Medicine and Community Health, Division of Environmental Toxicology, The University of Texas Medical Branch at Galveston, 700 Harborside Drive, Galveston, TX 77555-1110 (United States); Paolini, Moreno [Department of Pharmacology, Molecular Toxicology Unit, via Irnerio 48, I-40126, University of Bologna, Bologna (Italy); Abdel-Rahman, Sherif Z. [Department of Preventive Medicine and Community Health, Division of Environmental Toxicology, The University of Texas Medical Branch at Galveston, 700 Harborside Drive, Galveston, TX 77555-1110 (United States)]. E-mail: sabdelra@utmb.edu

2006-03-20

Epidemiological and animal studies linking high fruit and vegetable consumption to lower cancer risk have strengthened the belief that long-term administration of isolated naturally occurring dietary constituents could reduce the risk of cancer. In recent years, metabolites derived from phytoalexins, such as glucoraphanin found in broccoli and other cruciferous vegetables (Brassicaceae), have gained much attention as potential cancer chemopreventive agents. The protective effect of these micronutrients is assumed to be due to the inhibition of Phase-I carcinogen-bioactivating enzymes and/or induction of Phase-II detoxifying enzymes, an assumption that still remains uncertain. The protective effect of glucoraphanin is thought to be due to sulforaphane, an isothiocyanate metabolite produced from glucoraphanin by myrosinase. Here we show, in rat liver, that while glucoraphanin slightly induces Phase-II enzymes, it powerfully boosts Phase-I enzymes, including activators of polycyclic aromatic hydrocarbons (PAHs), nitrosamines and olefins. Induction of the cytochrome P450 (CYP) isoforms CYP1A1/2, CYP3A1/2 and CYP2E1 was confirmed by Western immunoblotting. CYP induction was paralleled by an increase in the corresponding mRNA levels. Concomitant with this Phase-I induction, we also found that glucoraphanin generated large amount of various reactive radical species, as determined by electron paramagnetic resonance (EPR) spectrometry coupled to a radical-probe technique. This suggests that long-term uncontrolled administration of glucoraphanin could actually pose a potential health hazard.

Glucoraphanin, the bioprecursor of the widely extolled chemopreventive agent sulforaphane found in broccoli, induces Phase-I xenobiotic metabolizing enzymes and increases free radical generation in rat liver

International Nuclear Information System (INIS)

Perocco, Paolo; Bronzetti, Giorgio; Canistro, Donatella; Valgimigli, Luca; Sapone, Andrea; Affatato, Alessandra; Pedulli, Gian Franco; Pozzetti, Laura; Broccoli, Massimiliano; Iori, Renato; Barillari, Jessica; Sblendorio, Valeriana; Legator, Marvin S.; Paolini, Moreno; Abdel-Rahman, Sherif Z.

2006-01-01

Epidemiological and animal studies linking high fruit and vegetable consumption to lower cancer risk have strengthened the belief that long-term administration of isolated naturally occurring dietary constituents could reduce the risk of cancer. In recent years, metabolites derived from phytoalexins, such as glucoraphanin found in broccoli and other cruciferous vegetables (Brassicaceae), have gained much attention as potential cancer chemopreventive agents. The protective effect of these micronutrients is assumed to be due to the inhibition of Phase-I carcinogen-bioactivating enzymes and/or induction of Phase-II detoxifying enzymes, an assumption that still remains uncertain. The protective effect of glucoraphanin is thought to be due to sulforaphane, an isothiocyanate metabolite produced from glucoraphanin by myrosinase. Here we show, in rat liver, that while glucoraphanin slightly induces Phase-II enzymes, it powerfully boosts Phase-I enzymes, including activators of polycyclic aromatic hydrocarbons (PAHs), nitrosamines and olefins. Induction of the cytochrome P450 (CYP) isoforms CYP1A1/2, CYP3A1/2 and CYP2E1 was confirmed by Western immunoblotting. CYP induction was paralleled by an increase in the corresponding mRNA levels. Concomitant with this Phase-I induction, we also found that glucoraphanin generated large amount of various reactive radical species, as determined by electron paramagnetic resonance (EPR) spectrometry coupled to a radical-probe technique. This suggests that long-term uncontrolled administration of glucoraphanin could actually pose a potential health hazard

Preclinical activity of the type II CD20 antibody GA101 (obinutuzumab) compared with rituximab and ofatumumab in vitro and in xenograft models.

Science.gov (United States)

Herter, Sylvia; Herting, Frank; Mundigl, Olaf; Waldhauer, Inja; Weinzierl, Tina; Fauti, Tanja; Muth, Gunter; Ziegler-Landesberger, Doris; Van Puijenbroek, Erwin; Lang, Sabine; Duong, Minh Ngoc; Reslan, Lina; Gerdes, Christian A; Friess, Thomas; Baer, Ute; Burtscher, Helmut; Weidner, Michael; Dumontet, Charles; Umana, Pablo; Niederfellner, Gerhard; Bacac, Marina; Klein, Christian

2013-10-01

We report the first preclinical in vitro and in vivo comparison of GA101 (obinutuzumab), a novel glycoengineered type II CD20 monoclonal antibody, with rituximab and ofatumumab, the two currently approved type I CD20 antibodies. The three antibodies were compared in assays measuring direct cell death (AnnexinV/PI staining and time-lapse microscopy), complement-dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cell-mediated phagocytosis (ADCP), and internalization. The models used for the comparison of their activity in vivo were SU-DHL4 and RL xenografts. GA101 was found to be superior to rituximab and ofatumumab in the induction of direct cell death (independent of mechanical manipulation required for cell aggregate disruption formed by antibody treatment), whereas it was 10 to 1,000 times less potent in mediating CDC. GA101 showed superior activity to rituximab and ofatumumab in ADCC and whole-blood B-cell depletion assays, and was comparable with these two in ADCP. GA101 also showed slower internalization rate upon binding to CD20 than rituximab and ofatumumab. In vivo, GA101 induced a strong antitumor effect, including complete tumor remission in the SU-DHL4 model and overall superior efficacy compared with both rituximab and ofatumumab. When rituximab-pretreated animals were used, second-line treatment with GA101 was still able to control tumor progression, whereas tumors escaped rituximab treatment. Taken together, the preclinical data show that the glyoengineered type II CD20 antibody GA101 is differentiated from the two approved type I CD20 antibodies rituximab and ofatumumab by its overall preclinical activity, further supporting its clinical investigation. ©2013 AACR.

Effect of honokiol on the induction of drug-metabolizing enzymes in human hepatocytes

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Cho YY

2014-11-01

Full Text Available Yong-Yeon Cho,1 Hyeon-Uk Jeong,1 Jeong-Han Kim,2 Hye Suk Lee1 1College of Pharmacy, The Catholic University of Korea, Bucheon, Korea; 2Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea Abstract: Honokiol, 2-(4-hydroxy-3-prop-2-enyl-phenyl-4-prop-2-enyl-phenol, an active component of Magnolia officinalis and Magnolia grandiflora, exerts various pharmacological activities such as antitumorigenic, antioxidative, anti-inflammatory, neurotrophic, and antithrombotic effects. To investigate whether honokiol acts as a perpetrator in drug interactions, messenger ribonucleic acid (mRNA levels of phase I and II drug-metabolizing enzymes, including cytochrome P450 (CYP, UDP-glucuronosyltransferase (UGT, and sulfotransferase 2A1 (SULT2A1, were analyzed by real-time reverse transcription polymerase chain reaction following 48-hour honokiol exposure in three independent cryopreserved human hepatocyte cultures. Honokiol treatment at the highest concentration tested (50 µM increased the CYP2B6 mRNA level and CYP2B6-catalyzed bupropion hydroxylase activity more than two-fold in three different hepatocyte cultures, indicating that honokiol induces CYP2B6 at higher concentrations. However, honokiol treatment (0.5–50 µM did not significantly alter the mRNA levels of phase I enzymes (CYP1A2, CYP3A4, CYP2C8, CYP2C9, and CYP2C19 or phase II enzymes (UGT1A1, UGT1A4, UGT1A9, UGT2B7, and SULT2A1 in cryopreserved human hepatocyte cultures. CYP1A2-catalyzed phenacetin O-deethylase and CYP3A4-catalyzed midazolam 1'-hydroxylase activities were not affected by 48-hour honokiol treatment in cryopreserved human hepatocytes. These results indicate that honokiol is a weak CYP2B6 inducer and is unlikely to increase the metabolism of concomitant CYP2B6 substrates and cause pharmacokinetic-based drug interactions in humans. Keywords: honokiol, human hepatocytes, drug interactions, cytochrome P450, UDP-glucuronosyltransferases

Surgeon Involvement in Pre-Clinical Medical Education: Attitudes of Directors of Education

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Simon Turner

2012-04-01

Full Text Available Background: Application rates to surgical residencies have shown a downward trend recently. Introducing students to surgeons early in medical school can increase interest in surgery as a career and enhance the instruction of important surgical topics. Directors of undergraduate medical education have unique insight and influence regarding the participation of surgeons in pre-clinical education. Methods: To understand the attitudes of these educators towards surgeons as teachers in pre-clinical programs, a survey was administered to the directors of undergraduate medical education at each of the English-language medical schools in Canada. Results: Educators estimate the participation of surgeons in all categories of pre-clinical education to be low, despite being valuable, and think that it should be increased. The most significant barrier to participation identified was a lack of surgeons’ time. Conclusions: Despite the value of surgeons participating in pre-clinical education, their rate of participation is low. Steps should be taken to facilitate the involvement of surgeons in this phase of education, which may lead to improved education for students and increased student interest in surgery residencies.

Cranberries and Cancer: An Update of Preclinical Studies Evaluating the Cancer Inhibitory Potential of Cranberry and Cranberry Derived Constituents

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Katherine M. Weh

2016-08-01

Full Text Available Cranberries are rich in bioactive constituents reported to influence a variety of health benefits, ranging from improved immune function and decreased infections to reduced cardiovascular disease and more recently cancer inhibition. A review of cranberry research targeting cancer revealed positive effects of cranberries or cranberry derived constituents against 17 different cancers utilizing a variety of in vitro techniques, whereas in vivo studies supported the inhibitory action of cranberries toward cancers of the esophagus, stomach, colon, bladder, prostate, glioblastoma and lymphoma. Mechanisms of cranberry-linked cancer inhibition include cellular death induction via apoptosis, necrosis and autophagy; reduction of cellular proliferation; alterations in reactive oxygen species; and modification of cytokine and signal transduction pathways. Given the emerging positive preclinical effects of cranberries, future clinical directions targeting cancer or premalignancy in high risk cohorts should be considered.

Anti-oxidative stress regulator NF-E2-related factor 2 mediates the adaptive induction of antioxidant and detoxifying enzymes by lipid peroxidation metabolite 4-hydroxynonenal

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Huang Ying

2012-11-01

Full Text Available Abstract Background NF-E2-related factor 2 (NRF2 regulates a battery of antioxidative and phase II drug metabolizing/detoxifying genes through binding to the antioxidant response elements (ARE. NRF2-ARE signaling plays a central role in protecting cells from a wide spectrum of reactive toxic species including reactive oxygen/nitrogen species (RONS. 4-hydroxylnonenal (4-HNE is a major end product from lipid peroxidation of omega-6 polyunsaturated fatty acids (PUFA induced by oxidative stress, and it is highly reactive to nucleophilic sites in DNA and proteins, causing cytotoxicity and genotoxicity. In this study, we examined the role of NRF2 in regulating the 4-HNE induced gene expression of antioxidant and detoxifying enzymes. Results When HeLa cells were treated with 4-HNE, NRF2 rapidly transloated into the nucleus, as determined by the distribution of NRF2 tagged with the enhanced green fluorescent protein (EGFP and increased NRF2 protein in the nuclear fraction. Transcriptional activity of ARE-luciferase was significantly induced by 0.01-10 μM of 4-HNE in a dose-dependent manner, and the induction could be blocked by pretreatment with glutathione (GSH. 4-HNE induced transcriptional expression of glutathione S-transferase (GST A4, aldoketone reductase (AKR 1C1 and heme oxygenase-1 (HO-1, and the induction was attenuated by knocking down NRF2 using small interfering RNA. Conclusions NRF2 is critical in mediating 4-HNE induced expression of antioxidant and detoxifying genes. This may account for one of the major cellular defense mechanisms against reactive metabolites of lipids peroxidation induced by oxidative stress and protect cells from cytotoxicity.

Inductive reasoning.

Science.gov (United States)

Hayes, Brett K; Heit, Evan; Swendsen, Haruka

2010-03-01

Inductive reasoning entails using existing knowledge or observations to make predictions about novel cases. We review recent findings in research on category-based induction as well as theoretical models of these results, including similarity-based models, connectionist networks, an account based on relevance theory, Bayesian models, and other mathematical models. A number of touchstone empirical phenomena that involve taxonomic similarity are described. We also examine phenomena involving more complex background knowledge about premises and conclusions of inductive arguments and the properties referenced. Earlier models are shown to give a good account of similarity-based phenomena but not knowledge-based phenomena. Recent models that aim to account for both similarity-based and knowledge-based phenomena are reviewed and evaluated. Among the most important new directions in induction research are a focus on induction with uncertain premise categories, the modeling of the relationship between inductive and deductive reasoning, and examination of the neural substrates of induction. A common theme in both the well-established and emerging lines of induction research is the need to develop well-articulated and empirically testable formal models of induction. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website. Copyright © 2010 John Wiley & Sons, Ltd.

Vitality Improvement of the Mediterranean Fruit Fly, Ceratitis capitata Wied 1- Measured by using dehydrogenase Enzyme Activities

International Nuclear Information System (INIS)

Salama, M.S.; Shoman, A.A.; Elbermawy, S.M.; Abul Yazid, I.

2000-01-01

The present study searches for the improvement vitality of the Mediterranean fruit fly, Ceratitis capitata Wied. Through the induction of a specific variance (mutation) in the genetic material. Several types of treatments that were thought to cause this mutation were used, as IGR's, temperature, formaldehyde, colchicine, alcohols, several types of larval rearing media and gamma-rays. Generally, the activities of the energy enzymes alpha-glycerophosphate dehydrogenase (alpha-GPDH) enzyme lactate dehydrogenase (LDH) enzyme and malate dehydrogenase (MDH) enzyme, when used as a direct measure for the fly vitality, increased due to treatments of the egg stage by the previously mentioned treatments specially by the usage of rice hulls in the larval rearing medium alone or followed by irradiation of the pupal stage with 90 Gy

Regulation of the expression of NADP-malic enzyme by UV-B, red and far-red light in maize seedlings

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P. Casati

1999-10-01

Full Text Available The induction of nicotinamide adenine dinucleotide phosphate-malic enzyme (NADP-ME in etiolated maize (Zea mays seedlings by UV-B and UV-A radiation, and different levels of photosynthetically active radiation (PAR, 400-700 nm was investigated by measuring changes in activity, protein quantity and RNA levels as a function of intensity and duration of exposure to the different radiations. Under low levels of PAR, exposure to UV-B radiation but not UV-A radiation for 6 to 24 h caused a marked increase in the enzyme levels similar to that observed under high PAR in the absence of UV-B. UV-B treatment of green leaves following a 12-h dark period also caused an increase in NADP-ME expression. Exposure to UV-B radiation for only 5 min resulted in a rapid increase of the enzyme, followed by a more gradual rise with longer exposure up to 6 h. Low levels of red light for 5 min or 6 h were also effective in inducing NADP-ME activity equivalent to that obtained with UV-B radiation. A 5-min exposure to far-red light following UV-B or red light treatment reversed the induction of NADP-ME, and this effect could be eliminated by further treatment with UV-B or red light. These results indicate that physiological levels of UV-B radiation can have a positive effect on the induction of this photosynthetic enzyme. The reducing power and pyruvate generated by the activity of NADP-ME may be used for respiration, in cellular repair processes and as substrates for fatty acid synthesis required for membrane repair.

Antibody induction versus corticosteroid induction for liver transplant recipients

DEFF Research Database (Denmark)

Penninga, Luit; Wettergren, André; Wilson, Colin H

2014-01-01

BACKGROUND: Liver transplantation is an established treatment option for end-stage liver failure. To date, no consensus has been reached on the use of immunosuppressive T-cell specific antibody induction compared with corticosteroid induction of immunosuppression after liver transplantation....... OBJECTIVES: To assess the benefits and harms of T-cell specific antibody induction versus corticosteroid induction for prevention of acute rejection in liver transplant recipients. SEARCH METHODS: We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register...... to identify additional trials. SELECTION CRITERIA: We included all randomised clinical trials assessing immunosuppression with T-cell specific antibody induction versus corticosteroid induction in liver transplant recipients. Our inclusion criteria stated that participants within each included trial should...

Preclinical QSP Modeling in the Pharmaceutical Industry: An IQ Consortium Survey Examining the Current Landscape

Science.gov (United States)

Wu, Fan; Bansal, Loveleena; Bradshaw‐Pierce, Erica; Chan, Jason R.; Liederer, Bianca M.; Mettetal, Jerome T.; Schroeder, Patricia; Schuck, Edgar; Tsai, Alice; Xu, Christine; Chimalakonda, Anjaneya; Le, Kha; Penney, Mark; Topp, Brian; Yamada, Akihiro

2018-01-01

A cross‐industry survey was conducted to assess the landscape of preclinical quantitative systems pharmacology (QSP) modeling within pharmaceutical companies. This article presents the survey results, which provide insights on the current state of preclinical QSP modeling in addition to future opportunities. Our results call attention to the need for an aligned definition and consistent terminology around QSP, yet highlight the broad applicability and benefits preclinical QSP modeling is currently delivering. PMID:29349875

Induction linacs

International Nuclear Information System (INIS)

Keefe, D.

1986-07-01

The principle of linear induction acceleration is described, and examples are given of practical configurations for induction linacs. These examples include the Advanced Technology Accelerator, Long Pulse Induction Linac, Radial Line Accelerator (RADLAC), and Magnetically-Insulated Electron-Focussed Ion Linac. A related concept, the auto accelerator, is described in which the high-current electron-beam technology in the sub-10 MeV region is exploited to produce electron beams at energies perhaps as high as the 100 to 1000 MeV range. Induction linacs for ions are also discussed. The efficiency of induction linear acceleration is analyzed

Preclinical renal cancer chemopreventive efficacy of geraniol by modulation of multiple molecular pathways

International Nuclear Information System (INIS)

Ahmad, Shiekh Tanveer; Arjumand, Wani; Seth, Amlesh; Nafees, Sana; Rashid, Summya; Ali, Nemat; Sultana, Sarwat

2011-01-01

Graphical abstract: Diagrammatic presentation of the hypothesis of the article in a concise manner. It reveals the chemopreventive efficacy of GOH possibly through the modulation of multiple molecular targets. GOH inhibits ROS generation, NFκB and PCNA expression thereby abrogating inflammation and proliferation of tubular cells of kidney. Whereas, GOH induces effector caspase-3 expression both through mitochondrial signalling pathway and death receptor signalling pathway. Highlights: → Geraniol modulates renal carcinogenesis in Wistar rats. → It abrogates Fe-NTA induced oxidative stress, inflammation and hyperproliferation. → Promotes apoptosis via induction of both mitochondrial and death receptor pathway. → Thus, inhibits renal carcinogenesis by modulating multiple molecular targets. -- Abstract: In the present study, we have evaluated the chemopreventive potential of geraniol (GOH), an acyclic monoterpene alcohol against ferric nitrilotriacetate (Fe-NTA) induced renal oxidative stress and carcinogenesis in Wistar rats. Chronic treatment of Fe-NTA induced oxidative stress, inflammation and cellular proliferation in Wistar rats. The chemopreventive efficacy of GOH was studied in terms of xenobiotic metabolizing enzyme activities, LPO, redox status, serum toxicity markers and the expression of putative nephrotoxicity biomarker Kim-1, tumor suppressor gene P53, inflammation, cell proliferation and apoptosis related genes in the kidney tissue. Oral administration of GOH at doses of 100 and 200 mg/kg b wt effectively suppressed renal oxidative stress and tumor incidence. Chemopreventive effects of GOH were associated with upregulation of xenobiotic metabolizing enzyme activities and down regulation of serum toxicity markers. GOH was able to down regulate expression of Kim-1, NFκB, PCNA, P53 along with induction of apoptosis. However, higher dose of GOH was more effective in modulating these multiple molecular targets both at transcriptional and protein

Reproducibility of preclinical animal research improves with heterogeneity of study samples

Science.gov (United States)

Vogt, Lucile; Sena, Emily S.; Würbel, Hanno

2018-01-01

Single-laboratory studies conducted under highly standardized conditions are the gold standard in preclinical animal research. Using simulations based on 440 preclinical studies across 13 different interventions in animal models of stroke, myocardial infarction, and breast cancer, we compared the accuracy of effect size estimates between single-laboratory and multi-laboratory study designs. Single-laboratory studies generally failed to predict effect size accurately, and larger sample sizes rendered effect size estimates even less accurate. By contrast, multi-laboratory designs including as few as 2 to 4 laboratories increased coverage probability by up to 42 percentage points without a need for larger sample sizes. These findings demonstrate that within-study standardization is a major cause of poor reproducibility. More representative study samples are required to improve the external validity and reproducibility of preclinical animal research and to prevent wasting animals and resources for inconclusive research. PMID:29470495

Induction of the pi class of glutathione S-transferase by carnosic acid in rat Clone 9 cells via the p38/Nrf2 pathway.

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Lin, Chia-Yuan; Wu, Chi-Rei; Chang, Shu-Wei; Wang, Yu-Jung; Wu, Jia-Jiuan; Tsai, Chia-Wen

2015-06-01

Induction of phase II enzymes is important in cancer chemoprevention. We compared the effect of rosemary diterpenes on the expression of the pi class of glutathione S-transferase (GSTP) in rat liver Clone 9 cells and the signaling pathways involved. Culturing cells with 1, 5, 10, or 20 μM carnosic acid (CA) or carnosol (CS) for 24 h in a dose-dependent manner increased the GSTP expression. CA was more potent than CS. The RNA level and the enzyme activity of GSTP were also enhanced by CA treatment. Treatment with 10 μM CA highly induced the reporter activity of the enhancer element GPEI. Furthermore, CA markedly increased the translocation of nuclear factor erythroid-2 related factor 2 (Nrf2) from the cytosol to the nucleus after 30 to 60 min. CA the stimulated the protein induction of p38, nuclear Nrf2, and GSTP was diminished in the presence of SB203580 (a p38 inhibitor). In addition, SB203580 pretreatment or silencing of Nrf2 by siRNA suppressed the CA-induced GPEI-DNA binding activity and GSTP protein expression. Knockdown of p38 or Nrf2 by siRNA abolished the activation of p38 and Nrf2 as well as the protein induction and enzyme activity of GSTP by CA. These results suggest that CA up-regulates the expression and enzyme activity of GSTP via the p38/Nrf2/GPEI pathway.

Antibody induction versus placebo, no induction, or another type of antibody induction for liver transplant recipients

DEFF Research Database (Denmark)

Penninga, Luit; Wettergren, André; Wilson, Colin H

2014-01-01

. All 19 trials were with high risk of bias. Of the 19 trials, 16 trials were two-arm trials, and three trials were three-arm trials. Hence, we found 25 trial comparisons with antibody induction agents: interleukin-2 receptor antagonist (IL-2 RA) versus no induction (10 trials with 1454 participants....... Furthermore, serum creatinine was statistically significantly higher when T-cell specific antibody induction was compared with no induction (MD 3.77 μmol/L, 95% CI 0.33 to 7.21; low-quality evidence), as well as when polyclonal T-cell specific antibody induction was compared with no induction, but this small...... T-cell specific antibody induction, drug-related adverse events were less common among participants treated with interleukin-2 receptor antagonists (RR 0.23, 95% CI 0.09 to 0.63; low-quality evidence), but this was caused by the results from one trial, and trial sequential analysis could not exclude...

Quantitative spectral K-edge imaging in preclinical photon-counting x-ray computed tomography.

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de Vries, Anke; Roessl, Ewald; Kneepkens, Esther; Thran, Axel; Brendel, Bernhard; Martens, Gerhard; Proska, Roland; Nicolay, Klaas; Grüll, Holger

2015-04-01

The objective of this study was to investigate the feasibility and the accuracy of spectral computed tomography (spectral CT) to determine the tissue concentrations and localization of high-attenuation, iodine-based contrast agents in mice. Iodine tissue concentrations determined with spectral CT are compared with concentrations measured with single-photon emission computed tomography (SPECT) and inductively coupled plasma mass spectrometry (ICP-MS). All animal procedures were performed according to the US National Institutes of Health principles of laboratory animal care and were approved by the ethical review committee of Maastricht, The Netherlands. Healthy Swiss mice (n = 4) were injected with an iodinated emulsion radiolabeled with indium as multimodal contrast agent for CT and SPECT. The CT and SPECT scans were acquired using a dedicated small-animal SPECT/CT system. Subsequently, scans were performed with a preclinical spectral CT scanner equipped with a photon-counting detector and 6 energy threshold levels. Quantitative data analysis of SPECT and spectral CT scans were obtained using 3-dimensional volumes-of-interest drawing methods. The ICP-MS on dissected organs was performed to determine iodine uptake per organ and was compared with the amounts determined from spectral CT and SPECT. Iodine concentrations obtained with image-processed spectral CT data correlated well with data obtained either with noninvasive SPECT imaging (slope = 0.96, r = 0.75) or with ICP-MS (slope = 0.99, r = 0.89) in tissue samples. This preclinical proof-of-concept study shows the in vivo quantification of iodine concentrations in tissues using spectral CT. Our multimodal imaging approach with spectral CT and SPECT using radiolabeled iodinated emulsions together with ICP-based quantification allows a direct comparison of all methods. Benchmarked against ICP-MS data, spectral CT in the present implementation shows a slight underestimation of organ iodine concentrations compared

The preclinical discovery and development of dolutegravir for the treatment of HIV.

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Bailly, Fabrice; Cotelle, Philippe

2015-01-01

Integration of the viral genome into the host cell chromatin is a central step in the replication cycle of HIV. Blocking the viral integrase (IN) enzyme therefore provides an attractive therapeutic strategy, as evidenced by the recent clinical approval of three IN strand transfer inhibitors. Dolutegravir is a therapy that is unique in its ability to evade HIV drug resistance in treatment-naïve patients. This review starts by providing a brief summary of the history of HIV-1 IN inhibitors. The authors follow this with details of the discovery and preclinical and clinical developments of dolutegravir. Finally, the authors provide details of dolutegravir's post-launch including the launch of the combination pill of dolutegravir, abacavir and lamivudine in August 2014. The launch of raltegravir, the first IN inhibitor from Merck & Co., has created new hopes for the patient. Indeed, pharmaceutical companies have not lost courage by attempting to address the major drawbacks of this first-in-class molecule. And while the drug elvitegravir has been inserted into a four-drug combination pill providing a once-daily dosing alternative, dolutegravir has demonstrated superiority in terms of its efficacy and resistance.

Identification of new epilepsy treatments: issues in preclinical methodology.

Science.gov (United States)

Galanopoulou, Aristea S; Buckmaster, Paul S; Staley, Kevin J; Moshé, Solomon L; Perucca, Emilio; Engel, Jerome; Löscher, Wolfgang; Noebels, Jeffrey L; Pitkänen, Asla; Stables, James; White, H Steve; O'Brien, Terence J; Simonato, Michele

2012-03-01

Preclinical research has facilitated the discovery of valuable drugs for the symptomatic treatment of epilepsy. Yet, despite these therapies, seizures are not adequately controlled in a third of all affected individuals, and comorbidities still impose a major burden on quality of life. The introduction of multiple new therapies into clinical use over the past two decades has done little to change this. There is an urgent demand to address the unmet clinical needs for: (1) new symptomatic antiseizure treatments for drug-resistant seizures with improved efficacy/tolerability profiles, (2) disease-modifying treatments that prevent or ameliorate the process of epileptogenesis, and (3) treatments for the common comorbidities that contribute to disability in people with epilepsy. New therapies also need to address the special needs of certain subpopulations, that is, age- or gender-specific treatments. Preclinical development in these treatment areas is complex due to heterogeneity in presentation and etiology, and may need to be formulated with a specific seizure, epilepsy syndrome, or comorbidity in mind. The aim of this report is to provide a framework that will help define future guidelines that improve and standardize the design, reporting, and validation of data across preclinical antiepilepsy therapy development studies targeting drug-resistant seizures, epileptogenesis, and comorbidities. Wiley Periodicals, Inc. © 2012 International League Against Epilepsy.

Preclinical Magnetic Resonance Fingerprinting (MRF) at 7 T: Effective Quantitative Imaging for Rodent Disease Models

Science.gov (United States)

Gao, Ying; Chen, Yong; Ma, Dan; Jiang, Yun; Herrmann, Kelsey A.; Vincent, Jason A.; Dell, Katherine M.; Drumm, Mitchell L.; Brady-Kalnay, Susann M.; Griswold, Mark A.; Flask, Chris A.; Lu, Lan

2015-01-01

High field, preclinical magnetic resonance imaging (MRI) scanners are now commonly used to quantitatively assess disease status and efficacy of novel therapies in a wide variety of rodent models. Unfortunately, conventional MRI methods are highly susceptible to respiratory and cardiac motion artifacts resulting in potentially inaccurate and misleading data. We have developed an initial preclinical, 7.0 T MRI implementation of the highly novel Magnetic Resonance Fingerprinting (MRF) methodology that has been previously described for clinical imaging applications. The MRF technology combines a priori variation in the MRI acquisition parameters with dictionary-based matching of acquired signal evolution profiles to simultaneously generate quantitative maps of T1 and T2 relaxation times and proton density. This preclinical MRF acquisition was constructed from a Fast Imaging with Steady-state Free Precession (FISP) MRI pulse sequence to acquire 600 MRF images with both evolving T1 and T2 weighting in approximately 30 minutes. This initial high field preclinical MRF investigation demonstrated reproducible and differentiated estimates of in vitro phantoms with different relaxation times. In vivo preclinical MRF results in mouse kidneys and brain tumor models demonstrated an inherent resistance to respiratory motion artifacts as well as sensitivity to known pathology. These results suggest that MRF methodology may offer the opportunity for quantification of numerous MRI parameters for a wide variety of preclinical imaging applications. PMID:25639694

A cost-effective simulation curriculum for preclinical endodontics.

Science.gov (United States)

Pileggi, Roberta; Glickman, Gerald N

2004-02-01

A challenge in contemporary dental education is to achieve a smooth transition from preclinical teaching environments to patient-care clinics in a cost-effective manner. The preclinical endodontic courses at The University of Texas, Dental Branch at Houston provide a unique learning environment that enables the student to perform endodontic treatment on extracted teeth in a typodont, and be involved in diagnosis and treatment-planning discussions. The specially designed stone typodont used has built-in radiographic capability, and is mounted at each chair in the clinic. During each preclinical session, students are assigned clinical cubicles and proper aseptic protocol is followed. Students are required to wear gloves, masks and eyewear, and place a rubber dam during treatment. Written self-assessment evaluations based upon prescribed criteria are utilised; feedback is given by faculty composed of both full-time endodontists and graduate students who periodically rotate and are calibrated on a regular basis. In the lecture phase, clinical case scenarios are presented to reinforce concepts of diagnosis and emergency care and to help integrate endodontics with other disciplines; a Socratic-like teaching style is established by the faculty facilitator to create an environment for developing critical-thinking and problem-solving skills. The overall feedback from graduating students has been very positive. Advantages of this format are an easier transition to patient management, a more keen interest in specialsation and a perceived increase in levels of confidence.

Combined preclinical magnetic particle imaging and magnetic resonance imaging. Initial results in mice

International Nuclear Information System (INIS)

Kaul, M.G.; Mummert, T.; Jung, C.; Raabe, N.; Ittrich, H.; Adam, G.; Heinen, U.; Reitmeier, A.

2015-01-01

Magnetic particle imaging (MPI) is a new radiologic imaging modality. For the first time, a commercial preclinical scanner is installed. The goal of this study was to establish a workflow between MPI and magnetic resonance imaging (MRI) scanners for a complete in vivo examination of a mouse and to generate the first co-registered in vivo MR-MP images. The in vivo examination of five mice were performed on a preclinical MPI scanner and a 7 Tesla preclinical MRI system. MRI measurements were used for anatomical referencing and validation of the injection of superparamagnetic iron oxide (SPIO) particles during a dynamic MPI scan. We extracted MPI data of the injection phase and co-registered it with MRI data. A workflow process for a combined in vivo MRI and MPI examination was established. A successful injection of ferucarbotran was proven in MPI and MRI. MR-MPI co-registration allocated the SPIOs in the inferior vena cava and the heart during and shortly after the injection. The acquisition of preclinical MPI and MRI data is feasible and allows the combined analysis of MR-MPI information.

Combined preclinical magnetic particle imaging and magnetic resonance imaging. Initial results in mice

Energy Technology Data Exchange (ETDEWEB)

Kaul, M.G.; Mummert, T.; Jung, C.; Raabe, N.; Ittrich, H.; Adam, G. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Diagnostic and Interventional Radiology; Weber, O. [Philips Medical Systems DMC GmbH, Hamburg (Germany); Heinen, U. [Bruker BioSpin MRI GmbH, Ettlingen (Germany); Reitmeier, A. [Medical Center Hamburg-Eppendorf, Hamburg (Germany). Animal Facility; Knopp, T. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Diagnostic and Interventional Radiology; Hamburg University of Technology, Hamburg (Germany)

2015-05-15

Magnetic particle imaging (MPI) is a new radiologic imaging modality. For the first time, a commercial preclinical scanner is installed. The goal of this study was to establish a workflow between MPI and magnetic resonance imaging (MRI) scanners for a complete in vivo examination of a mouse and to generate the first co-registered in vivo MR-MP images. The in vivo examination of five mice were performed on a preclinical MPI scanner and a 7 Tesla preclinical MRI system. MRI measurements were used for anatomical referencing and validation of the injection of superparamagnetic iron oxide (SPIO) particles during a dynamic MPI scan. We extracted MPI data of the injection phase and co-registered it with MRI data. A workflow process for a combined in vivo MRI and MPI examination was established. A successful injection of ferucarbotran was proven in MPI and MRI. MR-MPI co-registration allocated the SPIOs in the inferior vena cava and the heart during and shortly after the injection. The acquisition of preclinical MPI and MRI data is feasible and allows the combined analysis of MR-MPI information.

Spatial reversal learning in preclinical scrapie-inoculated mice.

Science.gov (United States)

Lysons, A M; Woollard, S J

1996-04-10

Acquisition and reversal of a two-choice spatial discrimination were tested in scrapie-inoculated mice. Both acquisition and reversal were normal in mice tested 138 and 103 days prior to the onset of clinical symptoms. At 65 days before onset of clinical symptoms, scrapie-inoculated mice required more trails to criterion in reversal learning, but this effect was not significant in a second experiment (68 days preclinical) and was transient: no effect was seen 33 days before symptoms. However, the course of reversal learning was abnormal in all three late preclinical groups (68, 65 and 33 days before symptoms). Reversal learning in these three groups was characterized by a rapid extinction of the original discrimination, followed by a period, absent in controls, during which performance showed no further improvement. This effect corresponds in time of onset to the appearance of characteristic neuropathological features.

Human cytosolic thymidine kinase: purification and physical characterization of the enzyme from HeLa cells

International Nuclear Information System (INIS)

Sherley, J.L.; Kelly, T.J.

1988-01-01

The mammalian cytosolic thymidine kinase is one of a number of enzymes involved in DNA replication whose activities increase dramatically during S phase of the cell cycle. As a first step in defining the mechanisms that control the S phase induction of thymidine kinase activity, the authors have purified the human enzyme from HeLa cells and raised a specific immune serum against the purified protein. The enzyme was isolated from cells arrested in S phase by treatment with methotrexate and purified to near homogeneity by ion-exchange and affinity chromatography. Stabilization of the purified enzyme was achieved by the addition of digitonin. An electrophoretic R/sub m/ of 0.2 in nondenaturing gels characterizes the purified enzyme activity as cytosolic thymidine kinase. The enzyme has a Stoke's radius of 40 A determined by gel filtration and a sedimentation coefficient of 5.5 S determined by glycerol gradient sedimentation. Based on these hydrodynamic values, a native molecular weight of 96,000 was calculated for the purified enzyme. When electrophoresed in denaturing sodium dodecyl sulfate-polyacrylamide gels under reducing conditions, the most purified enzyme fraction was found to contain one predominant polypeptide of M/sub r/ = 24,000. Several lines of evidence indicate that this polypeptide is responsible for thymidine kinase enzymatic activity

Computer-aided Molecular Design of Compounds Targeting Histone Modifying Enzymes

Science.gov (United States)

Andreoli, Federico; Del Rio, Alberto

2015-01-01

Growing evidences show that epigenetic mechanisms play crucial roles in the genesis and progression of many physiopathological processes. As a result, research in epigenetic grew at a fast pace in the last decade. In particular, the study of histone post-translational modifications encountered an extraordinary progression and many modifications have been characterized and associated to fundamental biological processes and pathological conditions. Histone modifications are the catalytic result of a large set of enzyme families that operate covalent modifications on specific residues at the histone tails. Taken together, these modifications elicit a complex and concerted processing that greatly contribute to the chromatin remodeling and may drive different pathological conditions, especially cancer. For this reason, several epigenetic targets are currently under validation for drug discovery purposes and different academic and industrial programs have been already launched to produce the first pre-clinical and clinical outcomes. In this scenario, computer-aided molecular design techniques are offering important tools, mainly as a consequence of the increasing structural information available for these targets. In this mini-review we will briefly discuss the most common types of known histone modifications and the corresponding operating enzymes by emphasizing the computer-aided molecular design approaches that can be of use to speed-up the efforts to generate new pharmaceutically relevant compounds. PMID:26082827

The preclinical evaluation of TIC10/ONC201 as an anti-pancreatic cancer agent.

Science.gov (United States)

Zhang, Qiangbo; Wang, Hong; Ran, Lin; Zhang, Zongli; Jiang, Runde

2016-08-05

Here we evaluated the potential anti-pancreatic cancer activity by TIC10/ONC201, a first-in-class small-molecule inducer of tumor necrosis (TNF)-related apoptosis-inducing ligand (TRAIL). The in vitro results showed that TIC10 induced potent cytotoxic and cytostatic activities in several human pancreatic cancer cell lines (Panc-1, Mia-PaCa2, AsPC-1 or L3.6). TIC10 activated both extrinsic (TRAIL-caspase-8-dependent) and endogenous/mitochondrial (caspase-9-dependent) apoptosis pathways in the pancreatic cancer cells. Molecularly, we showed that TIC10 inhibited Akt-Erk activation, yet induced TRAIL expression in pancreatic cancer cells. Significantly, TIC10, at a relatively low concentration, sensitized gemcitabine-induced growth inhibition and apoptosis against pancreatic cancer cells. Further, TIC10 and gemcitabine synergistically inhibited Panc-1 xenograft growth in SCID mice. The combination treatment also significantly improved mice survival. In addition, Akt-Erk in-activation and TRAIL/cleaved-caspase-8 induction were observed in TIC10-treated Panc-1 xenografts. Together, the preclinical results of the study demonstrate the potent anti-pancreatic cancer activity by TIC10, or with gemcitabine. Copyright © 2016 Elsevier Inc. All rights reserved.

A small-molecule inhibitor of the ubiquitin activating enzyme for cancer treatment.

Science.gov (United States)

Hyer, Marc L; Milhollen, Michael A; Ciavarri, Jeff; Fleming, Paul; Traore, Tary; Sappal, Darshan; Huck, Jessica; Shi, Judy; Gavin, James; Brownell, Jim; Yang, Yu; Stringer, Bradley; Griffin, Robert; Bruzzese, Frank; Soucy, Teresa; Duffy, Jennifer; Rabino, Claudia; Riceberg, Jessica; Hoar, Kara; Lublinsky, Anya; Menon, Saurabh; Sintchak, Michael; Bump, Nancy; Pulukuri, Sai M; Langston, Steve; Tirrell, Stephen; Kuranda, Mike; Veiby, Petter; Newcomb, John; Li, Ping; Wu, Jing Tao; Powe, Josh; Dick, Lawrence R; Greenspan, Paul; Galvin, Katherine; Manfredi, Mark; Claiborne, Chris; Amidon, Benjamin S; Bence, Neil F

2018-02-01

The ubiquitin-proteasome system (UPS) comprises a network of enzymes that is responsible for maintaining cellular protein homeostasis. The therapeutic potential of this pathway has been validated by the clinical successes of a number of UPS modulators, including proteasome inhibitors and immunomodulatory imide drugs (IMiDs). Here we identified TAK-243 (formerly known as MLN7243) as a potent, mechanism-based small-molecule inhibitor of the ubiquitin activating enzyme (UAE), the primary mammalian E1 enzyme that regulates the ubiquitin conjugation cascade. TAK-243 treatment caused depletion of cellular ubiquitin conjugates, resulting in disruption of signaling events, induction of proteotoxic stress, and impairment of cell cycle progression and DNA damage repair pathways. TAK-243 treatment caused death of cancer cells and, in primary human xenograft studies, demonstrated antitumor activity at tolerated doses. Due to its specificity and potency, TAK-243 allows for interrogation of ubiquitin biology and for assessment of UAE inhibition as a new approach for cancer treatment.

Human HepaRG Cells can be Cultured in Hanging-drop Plates for Cytochrome P450 Induction and Function Assays.

Science.gov (United States)

Murayama, Norie; Usui, Takashi; Slawny, Nicky; Chesné, Christophe; Yamazaki, Hiroshi

2015-01-01

Recent guidance/guidelines for industry recommend that cytochrome P450 induction can be assessed using human hepatocyte enzyme activity and/or mRNA levels to evaluate potential drug- drug interactions. To evaluate time-dependent cytochrome P450 induction precisely, induction of CYP1A2, CYP2B6, and CYP3A4 mRNA was confirmed (>2-fold) by the treatment with omeprazole, phenobarbital, and rifampicin, respectively, for 24 or 48 h on day 3 from the start of culture. After 24 h, the fold induction of CYP1A2 with 3.6 and 1.8x10(4) HepaRG cells per well was lower than that for 7.2x10(4) cells. CYP1A2 induction levels at 24 h were higher than those after 48 h. In contrast, higher CYP2B6 inductions were confirmed after 48 h exposure than after 24 h, independent of the number of cells per well. To help reduce the use of human cryopreserved hepatocytes, typical P450-dependent enzyme activities were investigated in human HepaRG cells cultured in commercial hanging-drop plates. Newly designed 96-well hanging-drop plates were capable of maintaining human CYP3A-dependent midazolam hydroxylation activities for up to 4 days using only 10% of the recommended initial 7.2x10(4) cells per well. Favorable HepaRG function using hanging-drop plates was confirmed by detecting 1'- hydroxymidazolam O-glucuronide on day 3, suggesting an improvement over traditional control plates in which this metabolite can be detected for 24-well plates. These results suggest that the catalytic function and/or induction of CYP1A2, CYP2B6, and CYP3A4 can be readily assessed with reduced numbers of starting HepaRG cells cultured in three-dimensional cultures in drops prepared with hanging-drop plates.

Enhanced cellulase production by Trichoderma harzianum by cultivation on glycerol followed by induction on cellulosic substrates.

Science.gov (United States)

Delabona, Priscila da Silva; Lima, Deise Juliana; Robl, Diogo; Rabelo, Sarita Cândida; Farinas, Cristiane Sanchez; Pradella, José Geraldo da Cruz

2016-05-01

The use of glycerol obtained as an intermediate of the biodiesel manufacturing process as carbon source for microbial growth is a potential alternative strategy for the production of enzymes and other high-value bioproducts. This work evaluates the production of cellulase enzymes using glycerol for high cell density growth of Trichoderma harzianum followed by induction with a cellulosic material. Firstly, the influence of the carbon source used in the pre-culture step was investigated in terms of total protein secretion and fungal morphology. Enzymatic productivity was then determined for cultivation strategies using different types and concentrations of carbon source, as well as different feeding procedures (batch and fed-batch). The best strategy for cellulase production was then further studied on a larger scale using a stirred tank bioreactor. The proposed strategy for cellulase production, using glycerol to achieve high cell density growth followed by induction with pretreated sugarcane bagasse, achieved enzymatic activities up to 2.27 ± 0.37 FPU/mL, 106.40 ± 8.87 IU/mL, and 9.04 ± 0.39 IU/mL of cellulase, xylanase, and β-glucosidase, respectively. These values were 2 times higher when compared to the control experiments using glucose instead of glycerol. This novel strategy proved to be a promising approach for improving cellulolytic enzymes production, and could potentially contribute to adding value to biomass within the biofuels sector.

Induction of erythroid differentiation in human erythroleukemia cells by depletion of malic enzyme 2.

Directory of Open Access Journals (Sweden)

Jian-Guo Ren

2010-09-01

Full Text Available Malic enzyme 2 (ME2 is a mitochondrial enzyme that catalyzes the conversion of malate to pyruvate and CO2 and uses NAD as a cofactor. Higher expression of this enzyme correlates with the degree of cell de-differentiation. We found that ME2 is expressed in K562 erythroleukemia cells, in which a number of agents have been found to induce differentiation either along the erythroid or the myeloid lineage. We found that knockdown of ME2 led to diminished proliferation of tumor cells and increased apoptosis in vitro. These findings were accompanied by differentiation of K562 cells along the erythroid lineage, as confirmed by staining for glycophorin A and hemoglobin production. ME2 knockdown also totally abolished growth of K562 cells in nude mice. Increased ROS levels, likely reflecting increased mitochondrial production, and a decreased NADPH/NADP+ ratio were noted but use of a free radical scavenger to decrease inhibition of ROS levels did not reverse the differentiation or apoptotic phenotype, suggesting that ROS production is not causally involved in the resultant phenotype. As might be expected, depletion of ME2 induced an increase in the NAD+/NADH ratio and ATP levels fell significantly. Inhibition of the malate-aspartate shuttle was insufficient to induce K562 differentiation. We also examined several intracellular signaling pathways and expression of transcription factors and intermediate filament proteins whose expression is known to be modulated during erythroid differentiation in K562 cells. We found that silencing of ME2 leads to phospho-ERK1/2 inhibition, phospho-AKT activation, increased GATA-1 expression and diminished vimentin expression. Metabolomic analysis, conducted to gain insight into intermediary metabolic pathways that ME2 knockdown might affect, showed that ME2 depletion resulted in high orotate levels, suggesting potential impairment of pyrimidine metabolism. Collectively our data point to ME2 as a potentially novel

Preclinical diagnosis of Alzheimer's disease: Prevention or prediction?

Directory of Open Access Journals (Sweden)

Ricardo Nitrini

Full Text Available Abstract The diagnosis of Alzheimer's disease (AD for cases with dementia may be too late to allow effective treatment. Criteria for diagnosis of preclinical AD suggested by the Alzheimer's Association include the use of molecular and structural biomarkers. Preclinical diagnosis will enable testing of new drugs and forms of treatment toward achieving successful preventive treatment. But what are the advantages for the individual? To know that someone who is cognitively normal is probably going to develop AD's dementia when there is no effective preventive treatment is definitely not good news. A research method whereby volunteers are assigned to receive treatment or placebo without knowing whether they are in the control or at-risk arm of a trial would overcome this potential problem. If these new criteria are used wisely they may represent a relevant milestone in the search for a definitive treatment for AD.

Differentiation of monkey embryonic stem cells to hepatocytes by feeder-free dispersion culture and expression analyses of cytochrome p450 enzymes responsible for drug metabolism.

Science.gov (United States)

Maruyama, Junya; Matsunaga, Tamihide; Yamaori, Satoshi; Sakamoto, Sakae; Kamada, Noboru; Nakamura, Katsunori; Kikuchi, Shinji; Ohmori, Shigeru

2013-01-01

We reported previously that monkey embryonic stem cells (ESCs) were differentiated into hepatocytes by formation of embryoid bodies (EBs). However, this EB formation method is not always efficient for assays using a large number of samples simultaneously. A dispersion culture system, one of the differentiation methods without EB formation, is able to more efficiently provide a large number of feeder-free undifferentiated cells. A previous study demonstrated the effectiveness of the Rho-associated kinase inhibitor Y-27632 for feeder-free dispersion culture and induction of differentiation of monkey ESCs into neural cells. In the present study, the induction of differentiation of cynomolgus monkey ESCs (cmESCs) into hepatocytes was performed by the dispersion culture method, and the expression and drug inducibility of cytochrome P450 (CYP) enzymes in these hepatocytes were examined. The cmESCs were successfully differentiated into hepatocytes under feeder-free dispersion culture conditions supplemented with Y-27632. The hepatocytes differentiated from cmESCs expressed the mRNAs for three hepatocyte marker genes (α-fetoprotein, albumin, CYP7A1) and several CYP enzymes, as measured by real-time polymerase chain reaction. In particular, the basal expression of cmCYP3A4 (3A8) in these hepatocytes was detected at mRNA and enzyme activity (testosterone 6β-hydroxylation) levels. Furthermore, the expression and activity of cmCYP3A4 (3A8) were significantly upregulated by rifampicin. These results indicated the effectiveness of Y-27632 supplementation for feeder-free dispersed culture and induction of differentiation into hepatocytes, and the expression of functional CYP enzyme(s) in cmESC-derived hepatic cells.

Development of computational small animal models and their applications in preclinical imaging and therapy research

NARCIS (Netherlands)

Xie, Tianwu; Zaidi, Habib

The development of multimodality preclinical imaging techniques and the rapid growth of realistic computer simulation tools have promoted the construction and application of computational laboratory animal models in preclinical research. Since the early 1990s, over 120 realistic computational animal

77 FR 71194 - Draft Guidance for Industry: Preclinical Assessment of Investigational Cellular and Gene Therapy...

Science.gov (United States)

2012-11-29

...] Draft Guidance for Industry: Preclinical Assessment of Investigational Cellular and Gene Therapy... Industry: Preclinical Assessment of Investigational Cellular and Gene Therapy Products,'' dated November... Evaluation (CBER), Office of Cellular, Tissue, and Gene Therapies (OCTGT). The product areas covered by this...

Preclinical evaluation of strontium-containing bioactive bone cement

International Nuclear Information System (INIS)

Li, Zhaoyang; Yuan, Ning; Lam, Raymond Wing Moon; Cui, Zhenduo; Yang, Xianjin; Lu, William Weijia

2013-01-01

Strontium (Sr) has become more attractive for orthopaedic applications as they can simultaneously stimulate bone formation and prevent bone loss. A Sr-containing bioactive bone cement (Sr-BC) has been designed to fix osteoporotic bone fracture. Sr is a trace element, so the safety of containing Sr is concerned when Sr-BC is implanted in human body. The preclinical assessment of biocompatibility of Sr-BC was conducted according to ISO 10993 standards. MTT assay showed that this bioactive bone cement was non-toxic to mouse fibroblasts, and it met the basic requirement for the orthopaedic implant. The three independent genetic toxicity studies including Ames, chromosome aberration and bone marrow micronucleus assays demonstrated absence of genotoxic components in Sr-BC, which reassured the safety concerns of this novel bone cement. The muscle implantation results in present study were also encouraging. The acute inflammation around the cement was observed at 1 week post-implantation; however, no significant difference was observed between control and Sr-BC groups. These responses may be attributed to the presence of the foreign body, but the tissue healed after 12 weeks implantation. In summary, the above preclinical results provide additional assurance for the safety of this implant. Sr-BC can be used as a potential alternative to the traditional bone cement. - Highlights: • Strontium-containing bioactive bone cement (Sr-BC) was designed. • The biocompatibility of Sr-BC was evaluated according ISO 10993 standards. • Preclinical results provide additional assurance for the safety of Sr-BC

Preclinical evaluation of strontium-containing bioactive bone cement

Energy Technology Data Exchange (ETDEWEB)

Li, Zhaoyang, E-mail: lizy@hku.hk [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong (China); Yuan, Ning [Department of Laboratory Medicine, Tianjin Chest Hospital, Tianjin 300051 (China); Lam, Raymond Wing Moon [Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong (China); Cui, Zhenduo; Yang, Xianjin [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Lu, William Weijia, E-mail: wwlu@hku.hk [Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong (China)

2013-12-01

Strontium (Sr) has become more attractive for orthopaedic applications as they can simultaneously stimulate bone formation and prevent bone loss. A Sr-containing bioactive bone cement (Sr-BC) has been designed to fix osteoporotic bone fracture. Sr is a trace element, so the safety of containing Sr is concerned when Sr-BC is implanted in human body. The preclinical assessment of biocompatibility of Sr-BC was conducted according to ISO 10993 standards. MTT assay showed that this bioactive bone cement was non-toxic to mouse fibroblasts, and it met the basic requirement for the orthopaedic implant. The three independent genetic toxicity studies including Ames, chromosome aberration and bone marrow micronucleus assays demonstrated absence of genotoxic components in Sr-BC, which reassured the safety concerns of this novel bone cement. The muscle implantation results in present study were also encouraging. The acute inflammation around the cement was observed at 1 week post-implantation; however, no significant difference was observed between control and Sr-BC groups. These responses may be attributed to the presence of the foreign body, but the tissue healed after 12 weeks implantation. In summary, the above preclinical results provide additional assurance for the safety of this implant. Sr-BC can be used as a potential alternative to the traditional bone cement. - Highlights: • Strontium-containing bioactive bone cement (Sr-BC) was designed. • The biocompatibility of Sr-BC was evaluated according ISO 10993 standards. • Preclinical results provide additional assurance for the safety of Sr-BC.

Is performance in pre-clinical assessment a good predictor of the final Doctor of Medicine grade?

Science.gov (United States)

Al-Wardy, Nadia M; Rizvi, Syed G; Bayoumi, Riad A

2009-12-01

To investigate if any correlation exists between students' grades on their final doctor of Medicine (MD) assessment and their overall preclinical grade point average (GPA) and its component parts. Student data available from the Deanship of Admissions and Registration were analyzed. Pearson correlation coefficient was obtained to assess the degree of linear relationship between performance in the preclinical and the MD assessment of 529 students who graduated from the College of Medicine and Health Sciences, Sultan Qaboos University, Al-Khoud, Oman from June 1998 to June 2005. Simple and multiple regression analyses were performed to evaluate individual and combined impact of the preclinical courses' grades on MD grades. Preclinical GPA correlated highly with MD GPA (r=0.641). The science component taught early in the preclinical phase correlated more strongly (r=0.457) than student electives (r=0.246). This correlation was better in the good English group. Students' performance, however, was best in electives, but worst in English. Most students who had low MD GPA (2.5, and limiting the credit hour requirement of electives by the College seems to be justified.

Preclinical Data on Efficacy of 10 Drug-Radiation Combinations: Evaluations, Concerns, and Recommendations

Directory of Open Access Journals (Sweden)

Helen B. Stone

2016-02-01

Full Text Available BACKGROUND: Clinical testing of new therapeutic interventions requires comprehensive, high-quality preclinical data. Concerns regarding quality of preclinical data have been raised in recent reports. This report examines the data on the interaction of 10 drugs with radiation and provides recommendations for improving the quality, reproducibility, and utility of future studies. The drugs were AZD6244, bortezomib, 17-DMAG, erlotinib, gefitinib, lapatinib, oxaliplatin/Lipoxal, sunitinib (Pfizer, Corporate headquarters, New York, NY, thalidomide, and vorinostat. METHODS: In vitro and in vivo data were tabulated from 125 published papers, including methods, radiation and drug doses, schedules of administration, assays, measures of interaction, presentation and interpretation of data, dosimetry, and conclusions. RESULTS: In many instances, the studies contained inadequate or unclear information that would hamper efforts to replicate or intercompare the studies, and that weakened the evidence for designing and conducting clinical trials. The published reports on these drugs showed mixed results on enhancement of radiation response, except for sunitinib, which was ineffective. CONCLUSIONS: There is a need for improved experimental design, execution, and reporting of preclinical testing of agents that are candidates for clinical use in combination with radiation. A checklist is provided for authors and reviewers to ensure that preclinical studies of drug-radiation combinations meet standards of design, execution, and interpretation, and report necessary information to ensure high quality and reproducibility of studies. Improved design, execution, common measures of enhancement, and consistent interpretation of preclinical studies of drug-radiation interactions will provide rational guidance for prioritizing drugs for clinical radiotherapy trials and for the design of such trials.

Preclinical efficacy and safety of herbal formulation for management ...

African Journals Online (AJOL)

Preclinical efficacy and safety of herbal formulation for management of wounds. ... The effects of the treatments on rate of wound closure, epithelialisation time ... inflammation and better tissue remodeling for rats treated with herbal product.

Content and goals of preclinical prosthodontic programs at german-language dental schools.

Science.gov (United States)

Hey, Jeremias; Stimmelmayr, Michael; Hirsch, Christian; Beuer, Florian

2014-04-01

The Association for Dental Education in Europe (ADEE) makes recommendations regarding the skills graduates of European dental schools need to achieve and advises dental schools regarding necessary changes to be made to the curriculum. In 2010 to 2011, a survey was conducted in German-language dental schools to validate the curricula and goals of preclinical prosthodontic programs with regard to laboratory work. The survey was mailed to the course instructors of the preclinical programs at 37 dental schools. Of these, 35 schools returned the completed survey, resulting in a response rate of 95%. Bent wire, wax-up exercises, metal-ceramic single crowns, fixed dental prostheses, cast metal single crowns, temporary removable dental prostheses, and full dentures were part of the dental laboratory work at most schools; however, most instructors considered laboratory work as less important, and there were few similarities among the programs in this area. According to the instructors responsible for preclinical education, honing of fine motor skills, realistic self-assessment, and the ability to work independently were the main goals of the programs. The results of this survey show that with regard to laboratory work, there were more differences than similarities among preclinical prosthodontic programs at German-language dental schools, contrary to the recommendations of the ADEE. These findings should be taken into account when program reforms are planned. © 2013 by the American College of Prosthodontists.

The putative cellodextrin transporter-like protein CLP1 is involved in cellulase induction in Neurospora crassa.

Science.gov (United States)

Cai, Pengli; Wang, Bang; Ji, Jingxiao; Jiang, Yongsheng; Wan, Li; Tian, Chaoguang; Ma, Yanhe

2015-01-09

Neurospora crassa recently has become a novel system to investigate cellulase induction. Here, we discovered a novel membrane protein, cellodextrin transporter-like protein 1 (CLP1; NCU05853), a putative cellodextrin transporter-like protein that is a critical component of the cellulase induction pathway in N. crassa. Although CLP1 protein cannot transport cellodextrin, the suppression of cellulase induction by this protein was discovered on both cellobiose and Avicel. The co-disruption of the cellodextrin transporters cdt2 and clp1 in strain Δ3βG formed strain CPL7. With induction by cellobiose, cellulase production was enhanced 6.9-fold in CPL7 compared with Δ3βG. We also showed that the suppression of cellulase expression by CLP1 occurred by repressing the expression of cellodextrin transporters, particularly cdt1 expression. Transcriptome analysis of the hypercellulase-producing strain CPL7 showed that the cellulase expression machinery was dramatically stimulated, as were the cellulase enzyme genes including the inducer transporters and the major transcriptional regulators. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

The Putative Cellodextrin Transporter-like Protein CLP1 Is Involved in Cellulase Induction in Neurospora crassa*

Science.gov (United States)

Cai, Pengli; Wang, Bang; Ji, Jingxiao; Jiang, Yongsheng; Wan, Li; Tian, Chaoguang; Ma, Yanhe

2015-01-01

Neurospora crassa recently has become a novel system to investigate cellulase induction. Here, we discovered a novel membrane protein, cellodextrin transporter-like protein 1 (CLP1; NCU05853), a putative cellodextrin transporter-like protein that is a critical component of the cellulase induction pathway in N. crassa. Although CLP1 protein cannot transport cellodextrin, the suppression of cellulase induction by this protein was discovered on both cellobiose and Avicel. The co-disruption of the cellodextrin transporters cdt2 and clp1 in strain Δ3βG formed strain CPL7. With induction by cellobiose, cellulase production was enhanced 6.9-fold in CPL7 compared with Δ3βG. We also showed that the suppression of cellulase expression by CLP1 occurred by repressing the expression of cellodextrin transporters, particularly cdt1 expression. Transcriptome analysis of the hypercellulase-producing strain CPL7 showed that the cellulase expression machinery was dramatically stimulated, as were the cellulase enzyme genes including the inducer transporters and the major transcriptional regulators. PMID:25398875

METHODOLOGICAL APPROACHES TO EXPERT EVALUATION OF PRECLINICAL AND CLINICAL TRIALS OF HUMAN IMMUNOGLOBULIN PRODUCTS

Directory of Open Access Journals (Sweden)

V. B. Ivanov

2017-01-01

Full Text Available The article considers the experience of Russian and leading foreign regulatory agencies in organisation and conduction of preclinical and clinical trials of human immunoglobulin products. The authors suggest a classification of human immunoglobulins and provide updated information on authorization of these products in Russia. The article summarizes methodological approaches, basic scientific principles and criteria relating to expert evaluation of preclinical and clinical trials of blood products. The authors further define the expert body’s requirements for data on preclinical and clinical trials of human normal immuniglobulins and human specific immunoglobulins for the prevention and/or treatment of infectious and non-infectious diseases which are submitted as part of applications for marketing authorization or marketing authorization variation. The article suggests programs of preclinical and clinical trials for human normal immunoglobulins and human specific immunoglobulins for the prevention and/or treatment of infectious and non-infectious diseases that are aligned with the Russian legislation and Eurasian Economic Union’s regulations on medicines circulation, and have been elaborated with respect to the guidelines of the European Medicines Agency.

Over expression of beta-1, 4-xylanase by auto-induction in E. coli

International Nuclear Information System (INIS)

Khan, M.I.K.; Sajjad, M.; Akhtar, W.

2013-01-01

Catalytic domain of β-1, 4-xylanase gene, (xynZ.CD) of Clostridium thermocellum was cloned in pET28a expression vector and over-expressed in Escherichia colt BL21 CodonPlus (RIL). The production of XynZ.CD in E. colt was optimized using different concentrations of lactose and induction of the enzyme at different stages of growth. The maximum growth of the cells and the enzyme activity were observed when the cells were induced with 10mM lactose after 8 hours of incubation. The enzyme was found to constitute >40% of the total cell proteins in the supernatant of the lysed cells transformed with recombinant pET28a/xynZ.CD. It was purified by heating the cell lysate at 65 degree C for 30 m followed by fractionation through FPLC. Molecular weight of XynZ.CD was found to be approximately 38,524 D by MALDI-TOF analysis. The enzyme variant was quite stable within broad pH range of 5.5 - 8.0 and it retained >85% of xylanase activity after 2 h incubation at 70 degre C. (author)

Induction machine handbook

CERN Document Server

Boldea, Ion

2002-01-01

Often called the workhorse of industry, the advent of power electronics and advances in digital control are transforming the induction motor into the racehorse of industrial motion control. Now, the classic texts on induction machines are nearly three decades old, while more recent books on electric motors lack the necessary depth and detail on induction machines.The Induction Machine Handbook fills industry's long-standing need for a comprehensive treatise embracing the many intricate facets of induction machine analysis and design. Moving gradually from simple to complex and from standard to

The role of radiolabelled compounds in preclinical drug development

International Nuclear Information System (INIS)

Hawkins, D.R.

1988-01-01

The role of radiolabelled compounds in the development of new drugs is discussed, with particular reference to their use in toxicological, metabolic and pharmacokinetic studies for the pre-clinical safety evaluation of new drugs. (U.K.)

Induction of biotransformation enzymes by the carcinogenic air-pollutant 3-nitrobenzanthrone in liver, kidney and lung, after intra-tracheal instillation in rats.

Science.gov (United States)

Mizerovská, Jana; Dračínská, Helena; Frei, Eva; Schmeiser, Heinz H; Arlt, Volker M; Stiborová, Marie

2011-02-28

3-Nitrobenzanthrone (3-NBA), a carcinogenic air pollutant, was investigated for its ability to induce cytochrome P450 (CYP) 1A1/2 and NAD(P)H:quinone oxidoreductase (NQO1) in liver, kidney and lung of rats treated by intra-tracheal instillation. The organs used were from a previous study performed to determine the persistence of 3-NBA-derived DNA adducts in target and non-target tissues (Bieler et al., Carcinogenesis 28 (2007) 1117-1121, [22]). NQO1 is the enzyme reducing 3-NBA to N-hydroxy-3-aminobenzanthrone (N-OH-3-ABA) and CYP1A enzymes oxidize a human metabolite of 3-NBA, 3-aminobenzanthrone (3-ABA), to yield the same reactive intermediate. 3-NBA and 3-ABA are both activated to species forming DNA adducts by cytosols and/or microsomes isolated from rat lung, the target organ for 3-NBA carcinogenicity, and from liver and kidney. Each compound generated the same five DNA adducts detectable by (32)P-postlabelling. When hepatic cytosols from rats treated with 0.2 or 2mg/kg body weight of 3-NBA were incubated with 3-NBA, DNA adduct formation was 3.2- and 8.6-fold higher, respectively, than in incubations with cytosols from control animals. Likewise, cytosols isolated from lungs and kidneys of rats exposed to 3-NBA more efficiently activated 3-NBA than those of control rats. This increase corresponded to an increase in protein levels and enzymatic activities of NQO1. Incubations of hepatic, pulmonary or renal microsomes of 3-NBA-treated rats with 3-ABA led to an 9.6-fold increase in DNA-adduct formation relative to controls. The highest induction in DNA-adduct levels was found in lung. The stimulation of DNA-adduct formation correlated with expression of CYP1A1/2 induced by the intra-tracheal instillation of 3-NBA. The results demonstrate that 3-NBA induces NQO1 and CYP1A1/2 in livers, lungs and kidneys of rats after intra-tracheal instillation, thereby enhancing its own genotoxic and carcinogenic potential. Copyright © 2010 Elsevier B.V. All rights reserved.

Investigations on the possible genotoxic effect of irradiated onion powder by means of prophage induction (inductest)

Energy Technology Data Exchange (ETDEWEB)

Farkas, J; Andrassy, E [Koezponti Elelmiszeripari Kutato Intezet, Budapest (Hungary)

1982-01-01

Aqueous extracts and enzymic digests of onion powder, untreated, irradiated with 5.0 and 10.0 kGy gamma radiation doses under aerobic conditions were tested with lysogenic strains GY 5022 and GY 5027 of Escherichia coli K12, for their prophage lambda inducing effect in the course of the genotoxicologic study carried out as a part of the wholesomeness testing of irradiated spices and condiments in the frame of the International Project in the Field of Food Irradiation (IFIP). The tests were carried out on onion powder stored for 3 months subsequent to radiation treatment. One ..mu..g of aflatoxin B/sub 1/ or 1 ..mu..g of streptozotocin per test was used as a positive control. The amounts of extracts and enzymic digests exposed to prophage induction test corresponded to about 55 mg and 22 mg, resp., of onion powder. While both aflatoxin and streptozotocin, known for their carcinogenic and mutagenic effect, exerted prophage induction, no statistically significant difference was observed between the frequency of spontaneous phage induction and that occurring in the presence of either untreated or irradiated onion powder. In tests carried out with thermally inducible lambdac 1857 test organisms (Escherichia coli K12 GY 5024 and GY 5029) onion powder, used in amounts as indicated above, did not damage either the prophage or the host organism in a way to affect the induced prophage propagating capacity of the cells.

Investigations on the possible genotoxic effect of irradiated onion powder by means of prophage induction (inductest)

International Nuclear Information System (INIS)

Farkas, J.; Andrassy, E.

1982-01-01

Aqueous extracts and enzymic digests of onion powder, untreated, irradiated with 5.0 and 10.0 kGy gamma radiation doses under aerobic conditions were tested with lysogenic strains GY 5022 and GY 5027 of Escherichia coli K12, for their prophage lambda inducing effect in the course of the genotoxicologic study carried out as a part of the wholesomeness testing of irradiated spices and condiments in the frame of the International Project in the Field of Food Irradiation (IFIP). The tests were carried out on onion powder stored for 3 months subsequent to radiation treatment. One μg of aflatoxin B 1 or 1 μg of streptozotocin per test was used as a positive control. The amounts of extracts and enzymic digests exposed to prophage induction test corresponded to about 55 mg and 22 mg, resp., of onion powder. While both aflatoxin and streptozotocin, known for their carcinogenic and mutagenic effect, exerted prophage induction, no statistically significant difference was observed between the frequency of spontaneous phage induction and that occurring in the presence of either untreated or irradiated onion powder. In tests carried out with thermally inducible lambdac 1857 test organisms (Escherichia coli K12 GY 5024 and GY 5029) onion powder, used in amounts as indicated above, did not damage either the prophage or the host organism in a way to affect the induced prophage propagating capacity of the cells. (author)

Pre-Clinical Medical Students' Exposure to and Attitudes Toward Pharmaceutical Industry Marketing.

Science.gov (United States)

Fein, Eric H; Vermillion, Michelle L; Uijtdehaage, Sebastian H J

2007-12-01

Background - Recent studies have examined the exposures and attitudes of physicians and third- and fourth-year medical students toward pharmaceutical industry marketing, but fewer studies have addressed these topics among pre-clinical medical students. Thus, the purpose of this study was to assess pre-clinical students' level of exposure to the pharmaceutical industry and their attitudes toward marketing. Method - First and second-year medical students at UCLA completed a 40-item survey based on previous studies. Results - Over three quarters of pre-clinical students (78.5% or 226 of 288) responded to the survey. Exposure to pharmaceutical industry marketing started very early in medical school. Most second-year students (77%) had received gifts including drug samples after three semesters. Most felt that this would not affect their future prescribing behavior. Conclusions - These findings and findings from related studies, coupled with the students' desire to learn more about the issue, suggest that an early educational intervention addressing this topic may be warranted in American medical schools.

Preclinical deposition of pathological prion protein in muscle of experimentally infected primates.

Directory of Open Access Journals (Sweden)

Susanne Krasemann

Full Text Available Prion diseases are transmissible fatal neurodegenerative disorders affecting humans and animals. A central step in disease progression is the accumulation of a misfolded form (PrP(Sc of the host encoded prion protein (PrP(C in neuronal and non-neuronal tissues. The involvement of peripheral tissues in preclinical states increases the risk of accidental transmission. On the other hand, detection of PrP(Sc in non-neuronal easy-accessible compartments such as muscle may offer a novel diagnostic tool. Primate models have proven invaluable to investigate prion diseases. We have studied the deposition of PrP(Sc in muscle and central nervous system of rhesus monkeys challenged with sporadic Creutzfeldt-Jakob disease (sCJD, variant CJD (vCJD and bovine spongiform encephalopathy (BSE in preclinical and clinical stage using biochemical and morphological methods. Here, we show the preclinical presence of PrP(Sc in muscle and central nervous system of rhesus monkeys experimentally infected with vCJD.

Peroxisomal enzymes in the liver of rats with experimental diabetes mellitus type 2.

Science.gov (United States)

Turecký, L; Kupčová, V; Uhlíková, E; Mojto, V

2014-01-01

Diabetes mellitus is relatively frequently associated with fatty liver disease. Increased oxidative stress probably plays an important role in the development of this hepatopathy. One of possible sources of reactive oxygen species in liver is peroxisomal system. There are several reports about changes of peroxisomal enzymes in experimental diabetes, mainly enzymes of fatty acid oxidation. The aim of our study was to investigate the possible changes of activities of liver peroxisomal enzymes, other than enzymes of beta-oxidation, in experimental diabetes mellitus type 2. Biochemical changes in liver of experimental animals suggest the presence of liver steatosis. The changes of serum parameters in experimental group are similar to changes in serum of patients with non-alcoholic fatty liver disease. We have shown that diabetes mellitus influenced peroxisomal enzymes by the different way. Despite of well-known induction of peroxisomal beta-oxidation, the activities of catalase, aminoacid oxidase and NADH-cytochrome b(5) reductase were not significantly changed and the activities of glycolate oxidase and NADP-isocitrate dehydrogenase were significantly decreased. The effect of diabetes on liver peroxisomes is probably due to the increased supply of fatty acids to liver in diabetic state and also due to increased oxidative stress. The changes of metabolic activity of peroxisomal compartment may participate on the development of diabetic hepatopathy.

Role of oxygen free radicals in the induction of sister chromatid exchanges by cigarette smoke

International Nuclear Information System (INIS)

Lee, C.K.; Brown, B.G.; Rice, W.Y. Jr.; Doolittle, D.J.

1989-01-01

Cigarette smoke has been reported to contain free radicals and free radical generators in both the gas and particulate phases. Studies in our laboratory have shown that both cigarette smoke condensate (CSC) and smoke bubbled through phosphate buffered saline solution (smoke-PBS) increased sister chromatid exchanges (SCE) in Chinese hamster ovary cells in a dose-dependent manner. Since oxygen free radicals have been shown to cause SCEs and other chromosomal damage, we investigated the role of these radicals in the induction of SCEs by CSC and smoke-PBS. Addition of the antioxidant enzymes catalase and superoxide dismutase or the oxygen-radical scavenger ascorbic acid failed to reduce the SCE frequency in the presence of either CSC or smoke-PBS. Additional studies indicated that the quantity of hydrogen peroxide produced in CSC or smoke-PBS is too small to account for the observed SCE induction. It appears, therefore, that SCE induction by CSC or smoke-PBS does not involve the participation of oxygen free radicals

Identification of new treatments for epilepsy: issues in preclinical methodology

Science.gov (United States)

Galanopoulou, Aristea S.; Buckmaster, Paul S.; Staley, Kevin J.; Moshé, Solomon L.; Perucca, Emilio; Engel, Jerome; Löscher, Wolfgang; Noebels, Jeffrey L.; Pitkänen, Asla; Stables, James; White, Steve H.; O’Brien, Terence J.; Simonato, Michele

2013-01-01

Summary Preclinical research has facilitated the discovery of valuable drugs for the symptomatic treatment of epilepsy. Yet, despite these therapies, seizures are not adequately controlled in a third of all affected individuals, and comorbidities still impose a major burden on quality of life. The introduction of multiple new therapies into clinical use over the past two decades has done little to change this. There is an urgent demand to address the unmet clinical needs for: (a) new symptomatic anti-seizure treatments for drug-resistant seizures with improved efficacy/tolerability profiles, (b) disease modifying treatments that prevent or ameliorate the epileptogenic state, and (c) treatments for the common comorbidities that contribute to disability in people with epilepsy. New therapies also need to address the special needs of certain subpopulations, i.e. age- or gender-specific treatments. Preclinical development in these treatment areas is complex due to heterogeneity in presentation and etiology, and may need to be formulated with a specific seizure, epilepsy syndrome or comorbidity in mind. The aim of this report is to provide a framework that will help define future guidelines that improve and standardize the design, reporting, and validation of data across preclinical anti-epilepsy therapy development studies targeting drug-resistant seizures, epileptogenesis and comorbidities. PMID:22292566

Modeling of pharmacokinetics of cocaine in human reveals the feasibility for development of enzyme therapies for drugs of abuse.

Directory of Open Access Journals (Sweden)

Fang Zheng

Full Text Available A promising strategy for drug abuse treatment is to accelerate the drug metabolism by administration of a drug-metabolizing enzyme. The question is how effectively an enzyme can actually prevent the drug from entering brain and producing physiological effects. In the present study, we have developed a pharmacokinetic model through a combined use of in vitro kinetic parameters and positron emission tomography data in human to examine the effects of a cocaine-metabolizing enzyme in plasma on the time course of cocaine in plasma and brain of human. Without an exogenous enzyme, cocaine half-lives in both brain and plasma are almost linearly dependent on the initial cocaine concentration in plasma. The threshold concentration of cocaine in brain required to produce physiological effects has been estimated to be 0.22±0.07 µM, and the threshold area under the cocaine concentration versus time curve (AUC value in brain (denoted by AUC2(∞ required to produce physiological effects has been estimated to be 7.9±2.7 µM·min. It has been demonstrated that administration of a cocaine hydrolase/esterase (CocH/CocE can considerably decrease the cocaine half-lives in both brain and plasma, the peak cocaine concentration in brain, and the AUC2(∞. The estimated maximum cocaine plasma concentration which a given concentration of drug-metabolizing enzyme can effectively prevent from entering brain and producing physiological effects can be used to guide future preclinical/clinical studies on cocaine-metabolizing enzymes. Understanding of drug-metabolizing enzymes is key to the science of pharmacokinetics. The general insights into the effects of a drug-metabolizing enzyme on drug kinetics in human should be valuable also in future development of enzyme therapies for other drugs of abuse.

Modeling of pharmacokinetics of cocaine in human reveals the feasibility for development of enzyme therapies for drugs of abuse.

Science.gov (United States)

Zheng, Fang; Zhan, Chang-Guo

2012-01-01

A promising strategy for drug abuse treatment is to accelerate the drug metabolism by administration of a drug-metabolizing enzyme. The question is how effectively an enzyme can actually prevent the drug from entering brain and producing physiological effects. In the present study, we have developed a pharmacokinetic model through a combined use of in vitro kinetic parameters and positron emission tomography data in human to examine the effects of a cocaine-metabolizing enzyme in plasma on the time course of cocaine in plasma and brain of human. Without an exogenous enzyme, cocaine half-lives in both brain and plasma are almost linearly dependent on the initial cocaine concentration in plasma. The threshold concentration of cocaine in brain required to produce physiological effects has been estimated to be 0.22±0.07 µM, and the threshold area under the cocaine concentration versus time curve (AUC) value in brain (denoted by AUC2(∞)) required to produce physiological effects has been estimated to be 7.9±2.7 µM·min. It has been demonstrated that administration of a cocaine hydrolase/esterase (CocH/CocE) can considerably decrease the cocaine half-lives in both brain and plasma, the peak cocaine concentration in brain, and the AUC2(∞). The estimated maximum cocaine plasma concentration which a given concentration of drug-metabolizing enzyme can effectively prevent from entering brain and producing physiological effects can be used to guide future preclinical/clinical studies on cocaine-metabolizing enzymes. Understanding of drug-metabolizing enzymes is key to the science of pharmacokinetics. The general insights into the effects of a drug-metabolizing enzyme on drug kinetics in human should be valuable also in future development of enzyme therapies for other drugs of abuse.

Collaborative learning in pre-clinical dental hygiene education.

Science.gov (United States)

Mueller-Joseph, Laura J; Nappo-Dattoma, Luisa

2013-04-01

Dental hygiene education continues to move beyond mastery of content material and skill development to learning concepts that promote critical-thinking and problem-solving skills. The purpose of this research was to evaluate the effectiveness of collaborative learning and determine the growth in intellectual development of 54 first-year dental hygiene students. The control group used traditional pre-clinical teaching and the experimental group used collaborative pedagogy for instrument introduction. All students were subjected to a post-test evaluating their ability to apply the principles of instrumentation. Intellectual development was determined using pre- and post-tests based on the Perry Scheme of Intellectual Development. Student attitudes were assessed using daily Classroom Assessment Activities and an end-of-semester departmental course evaluation. Findings indicated no significant difference between collaborative learning and traditional learning in achieving pre-clinical competence as evidenced by the students' ability to apply the principles of instrumentation. Advancement in intellectual development did not differ significantly between groups. Value added benefits of a collaborative learning environment as identified by the evaluation of student attitudes included decreased student reliance on authority, recognition of peers as legitimate sources of learning and increased self-confidence. A significant difference in student responses to daily classroom assessments was evident on the 5 days a collaborative learning environment was employed. Dental hygiene students involved in a pre-clinical collaborative learning environment are more responsible for their own learning and tend to have a more positive attitude toward the subject matter. Future studies evaluating collaborative learning in clinical dental hygiene education need to investigate the cost/benefit ratio of the value added outcomes of collaborative learning.

Assessment of the knowledge and attitudes regarding HIV/AIDS among pre-clinical medical students in Israel

Science.gov (United States)

2014-01-01

Background Today’s medical students are the future physicians of people living with HIV/AIDS (PLWHA). It is therefore essential that medical students possess the appropriate knowledge and attitudes regarding PLWHA. This study aims to evaluate knowledge and attitudes of pre-clinical Israeli medical students and to assess whether their knowledge and attitudes change throughout their pre-clinical studies. Methods A cross-sectional study was conducted among all pre-clinical medical students from the four medical schools in Israel during the academic year of 2010/2011 (a total of 1,470 students). A self-administered questionnaire was distributed. The questionnaire sought student responses pertaining to knowledge of HIV transmission and non-transmission routes, basic knowledge of HIV/AIDS treatment and attitudes towards HIV/AIDS. Results The study’s response rate was 62.24 percent. Knowledge among pre-clinical medical students was generally high and showed a statistically significant improvement as students progressed through their pre-clinical studies. However, there were some misconceptions, mostly regarding HIV transmission via breastfeeding and knowledge of HIV prevention after exposure to the virus. Students’ attitudes were found to include stigmatizing notions. Furthermore, the majority of medical students correlated HIV with shame and fear. In addition, students’ attitudes toward HIV testing and providing confidential medical information were contradictory to health laws, protocols and guidelines. Overall, no positive changes in students’ attitudes were observed during the pre-clinical years of medical school. Conclusion The knowledge of pre-clinical medical students in Israel is generally high, although there are some knowledge inadequacies that require more emphasis in the curricula of the medical schools. Contrary to HIV-related knowledge, medical students’ attitudes are unaffected by their progression through medical school. Therefore, medical

Plant Cell Protolytic Enzymes Activity under Exposure to Lectins of Endophytic and Epiphytic Azospirillum Strains

Directory of Open Access Journals (Sweden)

S.A. Alen’kina

2016-05-01

Full Text Available We studied the ability of lectins isolated from the surface of the two strains of nitrogen-fixing soil bacteria of the genus Azospirillum, A. brasilense Sp7 (epiphytic and A. brasilense Sp245 (endophytic, to show have a regulating effect on the activity of pectinolytic enzymes in the roots of wheat seedlings. Research results showed that the lectins under study can cause the induction of the activity of polygalacturonase, pectinesterase, pectatlyase from the plant cell wall, thereby ensuring the bacteria penetration in the plant tissues, as well as the induction of plants responses which, being combined with growth-stimulating effect of bacteria, contributes to the formation of plants stability and productivity.

Neonatal tolerance induction enables accurate evaluation of gene therapy for MPS I in a canine model.

Science.gov (United States)

Hinderer, Christian; Bell, Peter; Louboutin, Jean-Pierre; Katz, Nathan; Zhu, Yanqing; Lin, Gloria; Choa, Ruth; Bagel, Jessica; O'Donnell, Patricia; Fitzgerald, Caitlin A; Langan, Therese; Wang, Ping; Casal, Margret L; Haskins, Mark E; Wilson, James M

2016-09-01

High fidelity animal models of human disease are essential for preclinical evaluation of novel gene and protein therapeutics. However, these studies can be complicated by exaggerated immune responses against the human transgene. Here we demonstrate that dogs with a genetic deficiency of the enzyme α-l-iduronidase (IDUA), a model of the lysosomal storage disease mucopolysaccharidosis type I (MPS I), can be rendered immunologically tolerant to human IDUA through neonatal exposure to the enzyme. Using MPS I dogs tolerized to human IDUA as neonates, we evaluated intrathecal delivery of an adeno-associated virus serotype 9 vector expressing human IDUA as a therapy for the central nervous system manifestations of MPS I. These studies established the efficacy of the human vector in the canine model, and allowed for estimation of the minimum effective dose, providing key information for the design of first-in-human trials. This approach can facilitate evaluation of human therapeutics in relevant animal models, and may also have clinical applications for the prevention of immune responses to gene and protein replacement therapies. Copyright © 2016 Elsevier Inc. All rights reserved.

Preclinical Pharmacokinetic/Pharmacodynamic Modeling and Simulation in the Pharmaceutical Industry: An IQ Consortium Survey Examining the Current Landscape

OpenAIRE

Schuck, Edgar; Bohnert, Tonika; Chakravarty, Arijit; Damian-Iordache, Valeriu; Gibson, Christopher; Hsu, Cheng-Pang; Heimbach, Tycho; Krishnatry, Anu Shilpa; Liederer, Bianca M; Lin, Jing; Maurer, Tristan; Mettetal, Jerome T; Mudra, Daniel R; Nijsen, Marjoleen JMA; Raybon, Joseph

2015-01-01

The application of modeling and simulation techniques is increasingly common in preclinical stages of the drug discovery and development process. A survey focusing on preclinical pharmacokinetic/pharmacodynamics (PK/PD) analysis was conducted across pharmaceutical companies that are members of the International Consortium for Quality and Innovation in Pharmaceutical Development. Based on survey responses, ~68% of companies use preclinical PK/PD analysis in all therapeutic areas indicating its...

Image-guided drug delivery: preclinical applications and clinical translation

NARCIS (Netherlands)

Ojha, Tarun; Rizzo, Larissa; Storm, Gerrit; Kiessling, Fabian; Lammers, Twan Gerardus Gertudis Maria

2015-01-01

Image-guided drug delivery refers to the combination of drug targeting and imaging. Preclinically, image-guided drug delivery can be used for several different purposes, including for monitoring biodistribution, target site accumulation, off-target localization, drug release and drug efficacy.

Preclinical Polymodal Hallucinations for 13 Years before Dementia with Lewy Bodies

Science.gov (United States)

Abbate, Carlo; Trimarchi, Pietro Davide; Inglese, Silvia; Viti, Niccolò; Cantatore, Alessandra; De Agostini, Lisa; Pirri, Federico; Marino, Lorenza; Bagarolo, Renzo

2014-01-01

Objective. We describe a case of dementia with Lewy bodies (DLB) that presented long-lasting preclinical complex polymodal hallucinations. Background. Few studies have deeply investigated the characteristics of hallucinations in DLB, especially in the preclinical phase. Moreover, the clinical phenotype of mild cognitive impairment-(MCI-) DLB is poorly understood. Methods. The patient was followed for 4 years and a selective phenomenological and cognitive study was performed at the predementia stage. Results. The phenomenological study showed the presence of hypnagogic and hypnopompic hallucinations that allowed us to make a differential diagnosis between DLB and Charles Bonnet syndrome (CBS). The neuropsychological evaluation showed a multiple domain without amnesia MCI subtype with prefrontal dysexecutive, visuoperceptual, and visuospatial impairments and simultanagnosia, which has not previously been reported in MCI-DLB. Conclusions. This study extends the prognostic value of hallucinations for DLB to the preclinical phases. It supports and refines the MCI-DLB concept and identifies simultanagnosia as a possible early cognitive marker. Finally, it confirms an association between hallucinations and visuoperceptual impairments at an intermediate stage of the disease course and strongly supports the hypothesis that hallucinations in the earliest stages of DLB may reflect a narcolepsy-like REM-sleep disorder. PMID:24868122

The development of neural stimulators: a review of preclinical safety and efficacy studies.

Science.gov (United States)

Shepherd, Robert K; Villalobos, Joel; Burns, Owen; Nayagam, David

2018-05-14

Given the rapid expansion of the field of neural stimulation and the rigorous regulatory approval requirements required before these devices can be applied clinically, it is important that there is clarity around conducting preclinical safety and efficacy studies required for the development of this technology. The present review examines basic design principles associated with the development of a safe neural stimulator and describes the suite of preclinical safety studies that need to be considered when taking a device to clinical trial. Neural stimulators are active implantable devices that provide therapeutic intervention, sensory feedback or improved motor control via electrical stimulation of neural or neuro-muscular tissue in response to trauma or disease. Because of their complexity, regulatory bodies classify these devices in the highest risk category (Class III), and they are therefore required to go through a rigorous regulatory approval process before progressing to market. The successful development of these devices is achieved through close collaboration across disciplines including engineers, scientists and a surgical/clinical team, and the adherence to clear design principles. Preclinical studies form one of several key components in the development pathway from concept to product release of neural stimulators. Importantly, these studies provide iterative feedback in order to optimise the final design of the device. Key components of any preclinical evaluation include: in vitro studies that are focussed on device reliability and include accelerated testing under highly controlled environments; in vivo studies using animal models of the disease or injury in order to assess safety and, given an appropriate animal model, the efficacy of the technology under both passive and electrically active conditions; and human cadaver and ex vivo studies designed to ensure the device's form factor conforms to human anatomy, to optimise the surgical approach and to

Attitudes of Pre-Clinical and Clinical Medical Students to Psychiatry ...

African Journals Online (AJOL)

Attitudes of Pre-Clinical and Clinical Medical Students to Psychiatry. ... Nigerian Hospital Practice ... Abstract. Medical training provides an environment in which proper and professional attitudes towards psychiatric patients can be acquired.

Enzyme

Science.gov (United States)

Enzymes are complex proteins that cause a specific chemical change in all parts of the body. For ... use them. Blood clotting is another example of enzymes at work. Enzymes are needed for all body ...

Elective courses for medical students during the preclinical curriculum: a systematic review and evaluation

Directory of Open Access Journals (Sweden)

Ankit Agarwal

2015-05-01

Full Text Available Objective: Preclinical medical student electives are prevalent at medical schools across the United States, but the range of electives available and their impact on medical student education are not well described in the literature. The objective of this article is to review the literature relating to preclinical medical student electives and their impact on medical student educational outcomes. Methods: We reviewed studies that met the following criteria: English-language articles describing preclinical US-based medical electives. We used PubMed journal databases and limited our search for the time period 1999–2014. We excluded electives based in other countries or electives designed for third or fourth year students. Data abstracted included the topic of the elective, qualitative descriptions of the electives, and any associated surveys or exam data associated with the electives. Data were synthesized using descriptive tables sorting electives by broad topic. Reported outcomes and statistical methods were analyzed to assess study quality. Results: We found a wide range of subjects taught in the form of preclinical medical school electives. We identified electives in clinical skills, the humanities, student lifestyle, specialty-specific electives, and an assortment of other miscellaneous electives. Surveys and exams administered to students showed that the electives were universally well received by students. Of the 37 electives identified, 15 electives used quantitative objective assessments, such as knowledge exams, while the remaining tended to use student self-reported results. Conclusions: Preclinical medical student electives are prevalent at medical schools across the United States and have a significant impact on medical student education.

Biosafety preclinical trials of xenogenic, Allogeniec and autologous progenitor cells from fat tissue

OpenAIRE

Melikhova, Vs; Saburina, I.; Repin, V.; Novikova, N.; Murashev, A.; Orlov, A.

2008-01-01

Due to wide spread of new methods of regenerative medicine on basis of stem cells it has become increasingly necessary to establish standards of techniques using them. Preclinical trial of a new technology after receiving preliminary experiment results is a primary stage of its adoption. We carried out the experiments to assess biosafety of autogenous, allergenic and xenogeneic cultures of human and rat cells in models under standard preclinical experiments conditions used in a presentday pha...

Regulations of enzymes in animals: effects of developmental processes, cancer, and radiation. Comprehensive three-year progress report, 1 May 1972--30 April 1975

International Nuclear Information System (INIS)

Knox, W.E.

1975-01-01

Controls by genes and by adaptive phenomena of the patterns of enzymes in several rat tissues were extended by systematic investigations during development, in neoplasms, and after x-irradiation. Newly developed quantitative assays for tryptophan pyrrolase and phenylalanine hydroxylase were used to study the mechanism of degradation after induction of the former enzyme. Systematic investigation of the isoenzymic variants and of the quantitative pattern of enzymes in numerous rat tissues led to the discovery of new variants, the determination of the functional role of certain enzymes in specific tissues, and the identification of enzymes whose amount provides sensitive indicators fo neoplastic growth in rat liver and spleen. X-irradiation of young postnatal rats interfered with the development of some hepatic enzymes. This effect was distinct from that of tumor-bearing, and from abnormal hormonal or nutritional conditions. (U.S.)

Early bedside care during preclinical medical education: can technology-enhanced patient simulation advance the Flexnerian ideal?

Science.gov (United States)

Gordon, James A; Hayden, Emily M; Ahmed, Rami A; Pawlowski, John B; Khoury, Kimberly N; Oriol, Nancy E

2010-02-01

Flexner wanted medical students to study at the patient bedside-a remarkable innovation in his time-so that they could apply science to clinical care under the watchful eye of senior physicians. Ever since his report, medical schools have reserved the latter years of their curricula for such an "advanced" apprenticeship, providing clinical clerkship experiences only after an initial period of instruction in basic medical sciences. Although Flexner codified the segregation of preclinical and clinical instruction, he was committed to ensuring that both domains were integrated into a modern medical education. The aspiration to fully integrate preclinical and clinical instruction continues to drive medical education reform even to this day. In this article, the authors revisit the original justification for sequential preclinical-clinical instruction and argue that modern, technology-enhanced patient simulation platforms are uniquely powerful for fostering simultaneous integration of preclinical-clinical content in a way that Flexner would have applauded. To date, medical educators tend to focus on using technology-enhanced medical simulation in clinical and postgraduate medical education; few have devoted significant attention to using immersive clinical simulation among preclinical students. The authors present an argument for the use of dynamic robot-mannequins in teaching basic medical science, and describe their experience with simulator-based preclinical instruction at Harvard Medical School. They discuss common misconceptions and barriers to the approach, describe their curricular responses to the technique, and articulate a unifying theory of cognitive and emotional learning that broadens the view of what is possible, feasible, and desirable with simulator-based medical education.

D-arabinose metabolism in Escherichia coli B: induction and cotransductional mapping of the L-fucose-D-arabinose pathway enzymes.

Science.gov (United States)

Elsinghorst, E A; Mortlock, R P

1988-12-01

D-Arabinose is degraded by Escherichia coli B via some of the L-fucose pathway enzymes and a D-ribulokinase which is distinct from the L-fuculokinase of the L-fucose pathway. We found that L-fucose and D-arabinose acted as the apparent inducers of the enzymes needed for their degradation. These enzymes, including D-ribulokinase, appeared to be coordinately regulated, and mutants which constitutively synthesized the L-fucose enzymes also constitutively synthesized D-ribulokinase. In contrast to D-arabinose-positive mutants of E. coli K-12, in which L-fuculose-1-phosphate and D-ribulose-1-phosphate act as inducers of the L-fucose pathway, we found that these intermediates did not act as inducers in E. coli B. To further characterize the E. coli B system, some of the L-fucose-D-arabinose genes were mapped by using bacteriophage P1 transduction. A transposon Tn10 insertion near the E. coli B L-fucose regulon was used in two- and three-factor reciprocal crosses. The gene encoding D-ribulokinase, designated darK, was found to map within the L-fucose regulon, and the partial gene order was found to be Tn10-fucA-darK-fucI-fucK-thyA.

Preclinical animal research on therapy dosimetry with dual isotopes

NARCIS (Netherlands)

M.W. Konijnenberg (Mark); M. de Jong (Marion)

2011-01-01

textabstractPreclinical research into radionuclide therapies based on radiation dosimetry will enable the use of any LET-equivalent radionuclide. Radiation dose and dose rate have significant influence on dose effects in the tumour depending on its radiation sensitivity, possibilities for repair of

Subjective and Objective Evaluation of PBL Outcomes in Preclinical ...

African Journals Online (AJOL)

Subjective and Objective Evaluation of PBL Outcomes in Preclinical Medical Students. ... ABSTRACT: Problem based learning curriculum is widely recognized as a progressive, learner-centered, active learning approach and is currently used in the entire medical curriculum in over 10% of medical schools worldwide.

A generalizable pre-clinical research approach for orphan disease therapy

Directory of Open Access Journals (Sweden)

Beaulieu Chandree L

2012-06-01

Full Text Available Abstract With the advent of next-generation DNA sequencing, the pace of inherited orphan disease gene identification has increased dramatically, a situation that will continue for at least the next several years. At present, the numbers of such identified disease genes significantly outstrips the number of laboratories available to investigate a given disorder, an asymmetry that will only increase over time. The hope for any genetic disorder is, where possible and in addition to accurate diagnostic test formulation, the development of therapeutic approaches. To this end, we propose here the development of a strategic toolbox and preclinical research pathway for inherited orphan disease. Taking much of what has been learned from rare genetic disease research over the past two decades, we propose generalizable methods utilizing transcriptomic, system-wide chemical biology datasets combined with chemical informatics and, where possible, repurposing of FDA approved drugs for pre-clinical orphan disease therapies. It is hoped that this approach may be of utility for the broader orphan disease research community and provide funding organizations and patient advocacy groups with suggestions for the optimal path forward. In addition to enabling academic pre-clinical research, strategies such as this may also aid in seeding startup companies, as well as further engaging the pharmaceutical industry in the treatment of rare genetic disease.

Is medical students' moral orientation changeable after preclinical medical education?

Science.gov (United States)

Lin, Chaou-Shune; Tsou, Kuo-Inn; Cho, Shu-Ling; Hsieh, Ming-Shium; Wu, Hsi-Chin; Lin, Chyi-Her

2012-03-01

Moral orientation can affect ethical decision-making. Very few studies have focused on whether medical education can change the moral orientation of the students. The purpose of the present study was to document the types of moral orientation exhibited by medical students, and to study if their moral orientation was changed after preclinical education. From 2007 to 2009, the Mojac scale was used to measure the moral orientation of Taiwan medical students. The students included 271 first-year and 109 third-year students. They were rated as a communitarian, dual, or libertarian group and followed for 2 years to monitor the changes in their Mojac scores. In both first and third-year students, the dual group after 2 years of preclinical medical education did not show any significant change. In the libertarian group, first and third-year students showed a statistically significant increase from a score of 99.4 and 101.3 to 103.0 and 105.7, respectively. In the communitarian group, first and third-year students showed a significant decline from 122.8 and 126.1 to 116.0 and 121.5, respectively. During the preclinical medical education years, students with communitarian orientation and libertarian orientation had changed in their moral orientation to become closer to dual orientation. These findings provide valuable hints to medical educators regarding bioethics education and the selection criteria of medical students for admission.

Targetable vulnerabilities in T- and NK-cell lymphomas identified through preclinical models.

Science.gov (United States)

Ng, Samuel Y; Yoshida, Noriaki; Christie, Amanda L; Ghandi, Mahmoud; Dharia, Neekesh V; Dempster, Joshua; Murakami, Mark; Shigemori, Kay; Morrow, Sara N; Van Scoyk, Alexandria; Cordero, Nicolas A; Stevenson, Kristen E; Puligandla, Maneka; Haas, Brian; Lo, Christopher; Meyers, Robin; Gao, Galen; Cherniack, Andrew; Louissaint, Abner; Nardi, Valentina; Thorner, Aaron R; Long, Henry; Qiu, Xintao; Morgan, Elizabeth A; Dorfman, David M; Fiore, Danilo; Jang, Julie; Epstein, Alan L; Dogan, Ahmet; Zhang, Yanming; Horwitz, Steven M; Jacobsen, Eric D; Santiago, Solimar; Ren, Jian-Guo; Guerlavais, Vincent; Annis, D Allen; Aivado, Manuel; Saleh, Mansoor N; Mehta, Amitkumar; Tsherniak, Aviad; Root, David; Vazquez, Francisca; Hahn, William C; Inghirami, Giorgio; Aster, Jon C; Weinstock, David M; Koch, Raphael

2018-05-22

T- and NK-cell lymphomas (TCL) are a heterogenous group of lymphoid malignancies with poor prognosis. In contrast to B-cell and myeloid malignancies, there are few preclinical models of TCLs, which has hampered the development of effective therapeutics. Here we establish and characterize preclinical models of TCL. We identify multiple vulnerabilities that are targetable with currently available agents (e.g., inhibitors of JAK2 or IKZF1) and demonstrate proof-of-principle for biomarker-driven therapies using patient-derived xenografts (PDXs). We show that MDM2 and MDMX are targetable vulnerabilities within TP53-wild-type TCLs. ALRN-6924, a stapled peptide that blocks interactions between p53 and both MDM2 and MDMX has potent in vitro activity and superior in vivo activity across 8 different PDX models compared to the standard-of-care agent romidepsin. ALRN-6924 induced a complete remission in a patient with TP53-wild-type angioimmunoblastic T-cell lymphoma, demonstrating the potential for rapid translation of discoveries from subtype-specific preclinical models.

Linear induction accelerators

International Nuclear Information System (INIS)

Briggs, R.J.

1986-06-01

The development of linear induction accelerators has been motivated by applications requiring high-pulsed currents of charged particles at voltages exceeding the capability of single-stage, diode-type accelerators and at currents too high for rf accelerators. In principle, one can accelerate charged particles to arbitrarily high voltages using a multi-stage induction machine, but the 50-MeV, 10-kA Advanced Test Accelerator (ATA) at LLNL is the highest voltage machine in existence at this time. The advent of magnetic pulse power systems makes sustained operation at high-repetition rates practical, and this capability for high-average power is very likely to open up many new applications of induction machines in the future. This paper surveys the US induction linac technology with primary emphasis on electron machines. A simplified description of how induction machines couple energy to the electron beam is given, to illustrate many of the general issues that bound the design space of induction linacs

Utilization of blended learning to teach preclinical endodontics.

Science.gov (United States)

Maresca, Cristina; Barrero, Carlos; Duggan, Dereck; Platin, Enrique; Rivera, Eric; Hannum, Wallace; Petrola, Frank

2014-08-01

Blended learning (BL) is the integration of classroom learning with an online environment. The purpose of this study was to determine whether dental students who experienced BL in a preclinical endodontic course demonstrated better manual skills, conceptual knowledge, and learning experience compared to those experiencing traditional learning. All eighty-one students (100 percent) in a preclinical endodontics course agreed to participate and were assigned to either the traditional or BL group. A root canal procedure was used to determine the level of manual skills gained by each group. Pre- and post-intervention quizzes were given to all students to evaluate conceptual knowledge gained, and the students' perspectives on the methods were evaluated with a survey. The BL group scored better than the traditional group on the manual skills exercise at a statistically significant level (p=0.0067). There were no differences in the post-intervention quiz scores between the two groups, and the students' opinions were positive regarding BL. With BL, the students were able to learn and demonstrate dental skills at a high level.

Labor Induction

Science.gov (United States)

f AQ FREQUENTLY ASKED QUESTIONS FAQ154 LABOR, DELIVERY, AND POSTPARTUM CARE Labor Induction • What is labor induction? • Why is labor induced? • What is the Bishop score? • What is “ripening ...

Inductive reasoning 2.0.

Science.gov (United States)

Hayes, Brett K; Heit, Evan

2018-05-01

Inductive reasoning entails using existing knowledge to make predictions about novel cases. The first part of this review summarizes key inductive phenomena and critically evaluates theories of induction. We highlight recent theoretical advances, with a special emphasis on the structured statistical approach, the importance of sampling assumptions in Bayesian models, and connectionist modeling. A number of new research directions in this field are identified including comparisons of inductive and deductive reasoning, the identification of common core processes in induction and memory tasks and induction involving category uncertainty. The implications of induction research for areas as diverse as complex decision-making and fear generalization are discussed. This article is categorized under: Psychology > Reasoning and Decision Making Psychology > Learning. © 2017 Wiley Periodicals, Inc.

Demonstration of de novo synthesis of enzymes by density labelling with stable isotopes

International Nuclear Information System (INIS)

Huebner, G.; Hirschberg, K.

1977-01-01

The technique of in vivo density labelling of proteins with H 2 18 O and 2 H 2 O has been used to investigate hormonal regulation and developmental expression of enzymes in plant cells. Buoyant density data obtained from isopycnic equilibrium centrifugation demonstrated that the cytokinine-induced nitrate reductase activity and the gibberellic acid-induced phosphatase activity in isolated embryos of Agrostemma githago are activities of enzymes synthesized de novo. The increase in alanine-specific aminopeptidase in germinating A. githago seeds is not due to de novo synthesis but to the release of preformed enzyme. On the basis of this result it is possible to apply the enzyme aminopeptidase as an internal density standard in equilibrium centrifugation. Density labelling experiments on proteins in pea cotyledons have been used to study the change in the activity of acid phosphatase, alanine-specific aminopeptidase, and peroxidase during germination. The activities of these enzymes increase in cotyledons of Pisum sativum. Density labelling by 18 O and 2 H demonstrates de novo synthesis of these three enzymes. The differential time course of enzyme induction shows the advantage of using H 2 18 O as labelling substance in cases when the enzyme was synthesized immediately at the beginning of germination. At this stage of development the amino-acid pool available for synthesis is formed principally by means of hydrolysis of storage proteins. The incorporation of 2 H into the new proteins takes place in a measurable amount at a stage of growth in which the amino acids are also synthesized de novo. The enzyme acid phosphatase of pea cotyledons was chosen to demonstrate the possibility of using the density labelling technique to detect protein turnover. (author)

In vivo 3-dimensional photoacoustic imaging of the renal vasculature in preclinical rodent models

OpenAIRE

Ogunlade, O.; Connell, J. J.; Huang, J. L.; Zhang, E.; Lythgoe, M. F.; Long, D. A.; Beard, P.

2017-01-01

Non-invasive imaging of the kidney vasculature in preclinical murine models is important for studying renal development, diseases and evaluating new therapies, but is challenging to achieve using existing imaging modalities. Photoacoustic imaging is a promising new technique that is particularly well suited to visualising the vasculature and could provide an alternative to existing preclinical imaging methods for studying renal vascular anatomy and function. To investigate this, an all-optica...

The interplay between academic performance and quality of life among preclinical students.

Science.gov (United States)

Shareef, Mohammad Abrar; AlAmodi, Abdulhadi A; Al-Khateeb, Abdulrahman A; Abudan, Zainab; Alkhani, Mohammed A; Zebian, Sanderlla I; Qannita, Ahmed S; Tabrizi, Mariam J

2015-10-31

The high academic performance of medical students greatly influences their professional competence in long term career. Meanwhile, medical students greatly demand procuring a good quality of life that can help them sustain their medical career. This study examines validity and reliability of the tool among preclinical students and testifies the influence of their scholastic performance along with gender and academic year on their quality of life. A cross sectional study was conducted by distributing World Health Organization Quality of Life, WHOQOL-BREF, survey among medical students of year one to three at Alfaisal University. For validity, item discriminate validity(IDV) and confirmatory factor analysis were measured and for reliability, Cronbach's α test and internal item consistency(IIC) were examined. The association of GPA, gender and academic year with all major domains was drawn using Pearson's correlation, independent samples t-test and one-way ANOVA, respectively. A total of 335 preclinical students have responded to this questionnaire. The construct has demonstrated an adequate validity and good reliability. The high academic performance of students positively correlated with physical (r = 0.23, p student scored higher than female peers in physical and psychological health. This study has identified a direct relationship between the academic performance of preclinical students and their quality of life. The WHOQOL-BREF is a valid and reliable tool among preclinical students and the positive direction of high academic performance with greater QOL suggests that academic achievers procure higher satisfaction and poor achievers need a special attention for the improvement of their quality of life.

Development of computational small animal models and their applications in preclinical imaging and therapy research.

Science.gov (United States)

Xie, Tianwu; Zaidi, Habib

2016-01-01

The development of multimodality preclinical imaging techniques and the rapid growth of realistic computer simulation tools have promoted the construction and application of computational laboratory animal models in preclinical research. Since the early 1990s, over 120 realistic computational animal models have been reported in the literature and used as surrogates to characterize the anatomy of actual animals for the simulation of preclinical studies involving the use of bioluminescence tomography, fluorescence molecular tomography, positron emission tomography, single-photon emission computed tomography, microcomputed tomography, magnetic resonance imaging, and optical imaging. Other applications include electromagnetic field simulation, ionizing and nonionizing radiation dosimetry, and the development and evaluation of new methodologies for multimodality image coregistration, segmentation, and reconstruction of small animal images. This paper provides a comprehensive review of the history and fundamental technologies used for the development of computational small animal models with a particular focus on their application in preclinical imaging as well as nonionizing and ionizing radiation dosimetry calculations. An overview of the overall process involved in the design of these models, including the fundamental elements used for the construction of different types of computational models, the identification of original anatomical data, the simulation tools used for solving various computational problems, and the applications of computational animal models in preclinical research. The authors also analyze the characteristics of categories of computational models (stylized, voxel-based, and boundary representation) and discuss the technical challenges faced at the present time as well as research needs in the future.

Development of computational small animal models and their applications in preclinical imaging and therapy research

Energy Technology Data Exchange (ETDEWEB)

Xie, Tianwu [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva 4 CH-1211 (Switzerland); Zaidi, Habib, E-mail: habib.zaidi@hcuge.ch [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva 4 CH-1211 (Switzerland); Geneva Neuroscience Center, Geneva University, Geneva CH-1205 (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen 9700 RB (Netherlands)

2016-01-15

The development of multimodality preclinical imaging techniques and the rapid growth of realistic computer simulation tools have promoted the construction and application of computational laboratory animal models in preclinical research. Since the early 1990s, over 120 realistic computational animal models have been reported in the literature and used as surrogates to characterize the anatomy of actual animals for the simulation of preclinical studies involving the use of bioluminescence tomography, fluorescence molecular tomography, positron emission tomography, single-photon emission computed tomography, microcomputed tomography, magnetic resonance imaging, and optical imaging. Other applications include electromagnetic field simulation, ionizing and nonionizing radiation dosimetry, and the development and evaluation of new methodologies for multimodality image coregistration, segmentation, and reconstruction of small animal images. This paper provides a comprehensive review of the history and fundamental technologies used for the development of computational small animal models with a particular focus on their application in preclinical imaging as well as nonionizing and ionizing radiation dosimetry calculations. An overview of the overall process involved in the design of these models, including the fundamental elements used for the construction of different types of computational models, the identification of original anatomical data, the simulation tools used for solving various computational problems, and the applications of computational animal models in preclinical research. The authors also analyze the characteristics of categories of computational models (stylized, voxel-based, and boundary representation) and discuss the technical challenges faced at the present time as well as research needs in the future.

Development of computational small animal models and their applications in preclinical imaging and therapy research

International Nuclear Information System (INIS)

Xie, Tianwu; Zaidi, Habib

2016-01-01

The development of multimodality preclinical imaging techniques and the rapid growth of realistic computer simulation tools have promoted the construction and application of computational laboratory animal models in preclinical research. Since the early 1990s, over 120 realistic computational animal models have been reported in the literature and used as surrogates to characterize the anatomy of actual animals for the simulation of preclinical studies involving the use of bioluminescence tomography, fluorescence molecular tomography, positron emission tomography, single-photon emission computed tomography, microcomputed tomography, magnetic resonance imaging, and optical imaging. Other applications include electromagnetic field simulation, ionizing and nonionizing radiation dosimetry, and the development and evaluation of new methodologies for multimodality image coregistration, segmentation, and reconstruction of small animal images. This paper provides a comprehensive review of the history and fundamental technologies used for the development of computational small animal models with a particular focus on their application in preclinical imaging as well as nonionizing and ionizing radiation dosimetry calculations. An overview of the overall process involved in the design of these models, including the fundamental elements used for the construction of different types of computational models, the identification of original anatomical data, the simulation tools used for solving various computational problems, and the applications of computational animal models in preclinical research. The authors also analyze the characteristics of categories of computational models (stylized, voxel-based, and boundary representation) and discuss the technical challenges faced at the present time as well as research needs in the future

Pre-clinical cognitive phenotypes for Alzheimer disease: a latent profile approach.

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Hayden, Kathleen M; Kuchibhatla, Maragatha; Romero, Heather R; Plassman, Brenda L; Burke, James R; Browndyke, Jeffrey N; Welsh-Bohmer, Kathleen A

2014-11-01

Cognitive profiles for pre-clinical Alzheimer disease (AD) can be used to identify groups of individuals at risk for disease and better characterize pre-clinical disease. Profiles or patterns of performance as pre-clinical phenotypes may be more useful than individual test scores or measures of global decline. To evaluate patterns of cognitive performance in cognitively normal individuals to derive latent profiles associated with later onset of disease using a combination of factor analysis and latent profile analysis. The National Alzheimer Coordinating Centers collect data, including a battery of neuropsychological tests, from participants at 29 National Institute on Aging-funded Alzheimer Disease Centers across the United States. Prior factor analyses of this battery demonstrated a four-factor structure comprising memory, attention, language, and executive function. Factor scores from these analyses were used in a latent profile approach to characterize cognition among a group of cognitively normal participants (N = 3,911). Associations between latent profiles and disease outcomes an average of 3 years later were evaluated with multinomial regression models. Similar analyses were used to determine predictors of profile membership. Four groups were identified; each with distinct characteristics and significantly associated with later disease outcomes. Two groups were significantly associated with development of cognitive impairment. In post hoc analyses, both the Trail Making Test Part B, and a contrast score (Delayed Recall - Trails B), significantly predicted group membership and later cognitive impairment. Latent profile analysis is a useful method to evaluate patterns of cognition in large samples for the identification of preclinical AD phenotypes; comparable results, however, can be achieved with very sensitive tests and contrast scores. Copyright © 2014 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.

Prediction of antibiotic resistance: time for a new preclinical paradigm?

DEFF Research Database (Denmark)

Sommer, Morten Otto Alexander; Munck, Christian; Toft-Kehler, Rasmus Vendler

2017-01-01

Predicting the future is difficult, especially for evolutionary processes that are influenced by numerous unknown factors. Still, this is what is required of drug developers when they assess the risk of resistance arising against a new antibiotic candidate during preclinical development. In this ......Predicting the future is difficult, especially for evolutionary processes that are influenced by numerous unknown factors. Still, this is what is required of drug developers when they assess the risk of resistance arising against a new antibiotic candidate during preclinical development....... In this Opinion article, we argue that the traditional procedures that are used for the prediction of antibiotic resistance today could be markedly improved by including a broader analysis of bacterial fitness, infection dynamics, horizontal gene transfer and other factors. This will lead to more informed...

Induction of anti-tumor immunity by trifunctional antibodies in patients with peritoneal carcinomatosis

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Lindhofer Horst

2009-02-01

Full Text Available Abstract Peritoneal carcinomatosis (PC from epithelial tumors is a fatal diagnosis without efficient treatment. Trifunctional antibodies (trAb are novel therapeutic approaches leading to a concerted anti-tumor activity resulting in tumor cell destruction. In addition, preclinical data in mouse tumor models demonstrated the induction of long lasting tumor immunity after treatment with trAb. We describe the induction of anti-tumor specific T-lymphocytes after intraperitoneal administration of trAb in patients with PC. 9 patients with progressive PC from gastric (n = 6 and ovarian cancer (n = 2, and cancer of unknown primary (n = 1 received 3 escalating doses of trAb after surgery and/or ineffective chemotherapy. The trAb EpCAM × CD3 (10, 20, 40 μg or HER2/neu × CD3 (10, 40, 80 μg were applicated by intraperitoneal infusion. Four weeks after the last trAb application, all patients were restimulated by subdermal injection of trAb + autologous PBMC + irradiated autologous tumor cells. Immunological reactivity was tested by analyzing PBMC for specific tumor reactive CD4+/CD8+ T lymphocytes using an IFN-γ secretion assay. In 5 of 9 patients, tumor reactive CD4+/CD8+ T-lymphocytes increased significantly, indicating specific anti-tumor immunity. A clinical response (stable disease, partial regression has been observed in 5 of 9 patients, with a mean time to progression of 3.6 months. Follow-up showed a mean survival of 11.8 months (median 8.0 months after trAb therapy. TrAb are able to induce anti-tumor immunity after intraperitoneal application and restimulation. The induction of long-lasting anti-tumor immunity may provide an additional benefit of the intraperitoneal therapy with trAb and should be further elevated in larger clinical trials.

Increased hepatic nicotine elimination after phenobarbital induction in the conscious rat

International Nuclear Information System (INIS)

Foth, H.; Walther, U.I.; Kahl, G.F.

1990-01-01

Elimination parameters of [14C]nicotine in conscious rats receiving nicotine (0.3 mg/kg) either intravenously or orally were studied. The oral availability of unchanged nicotine, derived by comparison of the respective areas under the concentration vs time curves (AUC), was 89%, indicating low hepatic extraction ratios of about 10%. Pretreatment of rats with phenobarbital (PB) markedly increased hepatic first-pass extraction of nicotine. The oral availability of unchanged nicotine in plasma dropped to 1.4% of the corresponding values obtained from PB-treated rats receiving nicotine iv. After PB pretreatment, the clearance of iv nicotine was increased approximately twofold over controls, much less than the observed more than ninefold increase of hepatic first-pass extraction. It is assumed that extrahepatic metabolism contributed significantly to the rapid removal of nicotine from the plasma. The elimination of cotinine, originating from nicotine administered either po or iv, was significantly increased by PB pretreatment, as determined by the ratio of corresponding AUCs. The pattern of nicotine metabolites in urine also indicated an increase in the rate of cotinine metabolic turnover. The amount of norcotinine in the organic extract of urine paralleled PB microsomal enzyme induction. The ratio between urinary concentrations of the normetabolite and cotinine correlated strongly with the PB-induced state of rat liver. This may be a suitable indicator of PB-inducible hepatic cytochrome P450 isoenzyme(s). Since smoking habits in man are feedback-regulated by nicotine plasma concentrations, a similar increase of nicotine elimination by microsomal enzyme induction in man may be of relevance for tobacco consumption

Processing of poultry feathers by alkaline keratin hydrolyzing enzyme from Serratia sp. HPC 1383.

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Khardenavis, Anshuman A; Kapley, Atya; Purohit, Hemant J

2009-04-01

The present study describes the production and characterization of a feather hydrolyzing enzyme by Serratia sp. HPC 1383 isolated from tannery sludge, which was identified by the ability to form clear zones around colonies on milk agar plates. The proteolytic activity was expressed in terms of the micromoles of tyrosine released from substrate casein per ml per min (U/mL min). Induction of the inoculum with protein was essential to stimulate higher activity of the enzyme, with 0.03% feathermeal in the inoculum resulting in increased enzyme activity (45U/mL) that further increased to 90U/mL when 3d old inoculum was used. The highest enzyme activity, 130U/mL, was observed in the presence of 0.2% yeast extract. The optimum assay temperature and pH for the enzyme were found to be 60 degrees C and 10.0, respectively. The enzyme had a half-life of 10min at 60 degrees C, which improved slightly to 18min in presence of 1mM Ca(2+). Inhibition of the enzyme by phenylmethyl sulfonyl fluoride (PMSF) indicated that the enzyme was a serine protease. The enzyme was also partially inhibited (39%) by the reducing agent beta-mercaptoethanol and by divalent metal ions such as Zn(2+) (41% inhibition). However, Ca(2+) and Fe(2+) resulted in increases in enzyme activity of 15% and 26%, respectively. The kinetic constants of the keratinase were found to be 3.84 microM (K(m)) and 108.7 microM/mLmin (V(max)). These results suggest that this extracellular keratinase may be a useful alternative and eco-friendly route for handling the abundant amount of waste feathers or for applications in other industrial processes.

EGFR-targeted anti-cancer drugs in radiotherapy: Preclinical evaluation of mechanisms

International Nuclear Information System (INIS)

Baumann, Michael; Krause, Mechthild; Dikomey, Ekkehard; Dittmann, Klaus; Doerr, Wolfgang; Kasten-Pisula, Ulla; Rodemann, H. Peter

2007-01-01

Preclinical and clinical results indicate that the EGFR can mediate radioresistance in different solid human tumours. Combination of radiotherapy and EGFR inhibitors can improve local tumour control compared to irradiation alone and has been introduced into clinical radiotherapy practice. So far several mechanisms have been identified in preclinical studies to contribute to improved local tumour control after radiation combined with EGFR inhibitors. These include direct kill of cancer stem cells by EGFR inhibitors, cellular radiosensitization through modified signal transduction, inhibition of repair of DNA damage, reduced repopulation and improved reoxygenation during fractionated radiotherapy. Effects and mechanisms may differ for different classes of EGFR inhibitors, for different tumours and for normal tissues. The mechanisms underlying this heterogeneity are currently poorly understood, and predictive assays are not available yet. Importantly, mechanisms and predictors for the combined effects of radiation with EGFR inhibitors appear to be considerably different to those for application of EGFR inhibitors alone or in combination with chemotherapy. Therefore to further evaluate the efficacy and mechanisms of EGFR-inhibition in combined treatments, radiotherapy-specific preclinical research strategies, which include in vivo experiments using local tumour control as an endpoint, as well as animal studies on normal tissue toxicity are needed

Evaluation of Cholinergic Deficiency in Preclinical Alzheimer’s Disease Using Pupillometry

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Shaun Frost

2017-01-01

Full Text Available Cortical cholinergic deficiency is prominent in Alzheimer’s disease (AD, and published findings of diminished pupil flash response in AD suggest that this deficiency may extend to the visual cortical areas and anterior eye. Pupillometry is a low-cost, noninvasive technique that may be useful for monitoring cholinergic deficits which generally lead to memory and cognitive disorders. The aim of the study was to evaluate pupillometry for early detection of AD by comparing the pupil flash response (PFR in AD (N=14 and cognitively normal healthy control (HC, N=115 participants, with the HC group stratified according to high (N=38 and low (N=77 neocortical amyloid burden (NAB. Constriction phase PFR parameters were significantly reduced in AD compared to HC (maximum acceleration p<0.05, maximum velocity p<0.0005, average velocity p<0.005, and constriction amplitude p<0.00005. The high-NAB HC subgroup had reduced PFR response cross-sectionally, and also a greater decline longitudinally, compared to the low-NAB subgroup, suggesting changes to pupil response in preclinical AD. The results suggest that PFR changes may occur in the preclinical phase of AD. Hence, pupillometry has a potential as an adjunct for noninvasive, cost-effective screening for preclinical AD.

Enhancing translation: guidelines for standard pre-clinical experiments in mdx mice.

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Willmann, Raffaella; De Luca, Annamaria; Benatar, Michael; Grounds, Miranda; Dubach, Judith; Raymackers, Jean-Marc; Nagaraju, Kanneboyina

2012-01-01

Duchenne Muscular Dystrophy is an X-linked disorder that affects boys and leads to muscle wasting and death due to cardiac involvement and respiratory complications. The cause is the absence of dystrophin, a large structural protein indispensable for muscle cell function and viability. The mdx mouse has become the standard animal model for pre-clinical evaluation of potential therapeutic treatments. Recent years have seen a rapid increase in the number of experimental compounds being evaluated in the mdx mouse. There is, however, much variability in the design of these pre-clinical experimental studies. This has made it difficult to interpret and compare published data from different laboratories and to evaluate the potential of a treatment for application to patients. The authors therefore propose the introduction of a standard study design for the mdx mouse model. Several aspects, including animal care, sampling times and choice of tissues, as well as recommended endpoints and methodologies are addressed and, for each aspect, a standard procedure is proposed. Testing of all new molecules/drugs using a widely accepted and agreed upon standard experimental protocol would greatly improve the power of pre-clinical experimentations and help identifying promising therapies for the translation into clinical trials for boys with Duchenne Muscular Dystrophy. Copyright © 2011 Elsevier B.V. All rights reserved.

Preclinical Polymodal Hallucinations for 13 Years before Dementia with Lewy Bodies

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Carlo Abbate

2014-01-01

Full Text Available Objective. We describe a case of dementia with Lewy bodies (DLB that presented long-lasting preclinical complex polymodal hallucinations. Background. Few studies have deeply investigated the characteristics of hallucinations in DLB, especially in the preclinical phase. Moreover, the clinical phenotype of mild cognitive impairment-(MCI- DLB is poorly understood. Methods. The patient was followed for 4 years and a selective phenomenological and cognitive study was performed at the predementia stage. Results. The phenomenological study showed the presence of hypnagogic and hypnopompic hallucinations that allowed us to make a differential diagnosis between DLB and Charles Bonnet syndrome (CBS. The neuropsychological evaluation showed a multiple domain without amnesia MCI subtype with prefrontal dysexecutive, visuoperceptual, and visuospatial impairments and simultanagnosia, which has not previously been reported in MCI-DLB. Conclusions. This study extends the prognostic value of hallucinations for DLB to the preclinical phases. It supports and refines the MCI-DLB concept and identifies simultanagnosia as a possible early cognitive marker. Finally, it confirms an association between hallucinations and visuoperceptual impairments at an intermediate stage of the disease course and strongly supports the hypothesis that hallucinations in the earliest stages of DLB may reflect a narcolepsy-like REM-sleep disorder.

Monochromatic minibeam radiotherapy: theoretical and experimental dosimetry for preclinical treatment plans

Energy Technology Data Exchange (ETDEWEB)

Deman, P; Vautrin, M; Stupar, V; Barbier, E L; Elleaume, H; Esteve, F; Adam, J F, E-mail: adam@esrf.fr [INSERM, U836, BP 170, Grenoble Cedex 9, F-38042 (France)

2011-07-21

Monochromatic x-ray minibeam radiotherapy is a new radiosurgery approach based on arrays of submillimetric interlaced planar x-ray beams. The aim of this study was to characterize the dose distributions obtained with this new modality when being used for preclinical trials. Monte Carlo simulations were performed in water phantoms. Percentage depth-dose curves and dose profiles were computed for single incidences and interleaved incidences of 80 keV planar x-ray minibeam (0.6 x 5 mm) arrays. Peak to valley dose ratios were also computed at various depths for an increasing number of minibeams. 3D experimental polymer gel (nPAG) dosimetry measurements were performed using MRI devices designed for small animal imaging. These very high spatial resolution (50 {mu}m) dose maps were compared to the simulations. Preclinical minibeams dose distributions were fully characterized. Experimental dosimetry correlated well with Monte Carlo calculations (Student t-tests: p > 0.1). F98 tumor-bearing rats were also irradiated with interleaved minibeams (80 keV, prescribed dose: 25 Gy). This associated preclinical trial serves as a proof of principle of the technique. The mean survival time of irradiated glioma-bearing rats increased significantly, when compared to the untreated animals (59.6 {+-} 2.8 days versus 28.25 {+-} 0.75 days, p < 0.001).

Preclinical Alzheimer's disease: Definition, natural history, and diagnostic criteria.

Science.gov (United States)

Dubois, Bruno; Hampel, Harald; Feldman, Howard H; Scheltens, Philip; Aisen, Paul; Andrieu, Sandrine; Bakardjian, Hovagim; Benali, Habib; Bertram, Lars; Blennow, Kaj; Broich, Karl; Cavedo, Enrica; Crutch, Sebastian; Dartigues, Jean-François; Duyckaerts, Charles; Epelbaum, Stéphane; Frisoni, Giovanni B; Gauthier, Serge; Genthon, Remy; Gouw, Alida A; Habert, Marie-Odile; Holtzman, David M; Kivipelto, Miia; Lista, Simone; Molinuevo, José-Luis; O'Bryant, Sid E; Rabinovici, Gil D; Rowe, Christopher; Salloway, Stephen; Schneider, Lon S; Sperling, Reisa; Teichmann, Marc; Carrillo, Maria C; Cummings, Jeffrey; Jack, Cliff R

2016-03-01

During the past decade, a conceptual shift occurred in the field of Alzheimer's disease (AD) considering the disease as a continuum. Thanks to evolving biomarker research and substantial discoveries, it is now possible to identify the disease even at the preclinical stage before the occurrence of the first clinical symptoms. This preclinical stage of AD has become a major research focus as the field postulates that early intervention may offer the best chance of therapeutic success. To date, very little evidence is established on this "silent" stage of the disease. A clarification is needed about the definitions and lexicon, the limits, the natural history, the markers of progression, and the ethical consequence of detecting the disease at this asymptomatic stage. This article is aimed at addressing all the different issues by providing for each of them an updated review of the literature and evidence, with practical recommendations. Copyright © 2016 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

Subjective memory complaints in preclinical autosomal dominant Alzheimer disease.

Science.gov (United States)

Norton, Daniel J; Amariglio, Rebecca; Protas, Hillary; Chen, Kewei; Aguirre-Acevedo, Daniel C; Pulsifer, Brendan; Castrillon, Gabriel; Tirado, Victoria; Munoz, Claudia; Tariot, Pierre; Langbaum, Jessica B; Reiman, Eric M; Lopera, Francisco; Sperling, Reisa A; Quiroz, Yakeel T

2017-10-03

To cross-sectionally study subjective memory complaints (SMC) in autosomal dominant Alzheimer disease (ADAD). We examined self-reported and study partner-based SMC in 52 young, cognitively unimpaired individuals from a Colombian kindred with early-onset ADAD. Twenty-six carried the PSEN-1 E280A mutation, averaging 7 years of age younger than the kindred's expected clinical onset. Twenty-six were age-matched noncarriers. Participants also underwent structural MRI and cognitive testing. Self-reported SMC were greater in carriers than noncarriers ( p = 0.02). Study partner-based SMC did not differ between groups ( p = 0.21), but in carriers increased with age ( r = 0.66, p < 0.001) and decreased with hippocampal volume ( r = -0.35, p = 0.08). Cognitively unimpaired PSEN-1 carriers have elevated SMC. Self-reported SMC may be a relatively early indicator of preclinical AD, while partner- reported SMC increases later in preclinical AD, closer to clinical onset. © 2017 American Academy of Neurology.

Ginsenoside Rb1 for Myocardial Ischemia/Reperfusion Injury: Preclinical Evidence and Possible Mechanisms

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Qun Zheng

2017-01-01

Full Text Available Ginseng is an important herbal drug that has been used worldwide for many years. Ginsenoside Rb1 (G-Rb1, the major pharmacological extract from ginseng, possesses a variety of biological activities in the cardiovascular systems. Here, we conducted a preclinical systematic review to investigate the efficacy of G-Rb1 for animal models of myocardial ischemia/reperfusion injury and its possible mechanisms. Ten studies involving 211 animals were identified by searching 6 databases from inception to May 2017. The methodological quality was assessed by using the CAMARADES 10-item checklist. All the data were analyzed using RevMan 5.3 software. As a result, the score of study quality ranged from 3 to 7 points. Meta-analyses showed that G-Rb1 can significantly decrease the myocardial infarct size and cardiac enzymes (including lactate dehydrogenase, creatine kinase, and creatine kinase-MB when compared with control group (P<0.01. Significant decrease in cardiac troponin T and improvement in the degree of ST-segment depression were reported in one study (P<0.05. Additionally, the possible mechanisms of G-Rb1 for myocardial infarction are antioxidant, anti-inflammatory, antiapoptosis, promoting angiogenesis and improving the circulation. Thus, G-Rb1 is a potential cardioprotective candidate for further clinical trials of myocardial infarction.

Induction of monooxygenation in rainbow trout by polybrominated biphenyls: a comparative study.

Science.gov (United States)

Elcombe, C R; Lech, J J

1978-01-01

Two commercial polychlorinated biphenyl mixtures (Aroclor 1254 and Aroclor 1242) and one polybrominated biphenyl mixture (FireMaster BP-6) were examined for their abilities to induce hepatic microsomal monooxygenation in rainbow trout (Salmo gairdneri). Pretreatment of rainbow trout with Aroclors 1254 and 1242 (150 mg/kg IP) resulted in an approximate 10-fold induction of arylhydrocarbon (benzo[a]pyrene) hydroxylation, ethoxycoumarin-O-deethylation and ethoxyresorufin-O-deethylation within 7 days after injection. These enzyme activities remained elevated above control values for at least 2-3 weeks. Administration of FireMaster BP-6 (150 mg/kg IP) also resulted in an induction of several monooxygenase activities. Arylhydrocarbon (benzo[a]pyrene) hydroxylation, ethoxycoumarin-O-deethylation and ethoxyresorufin-O-deethylation were increased by 6-, 3,- and 25-fold, respectively. Only the latter two activities remained elevated two weeks post-injection. Ethylmorphine-N-demethylation was unaffected by the polyhalogenated biphenyls. Significant increases in P-450 hemoprotein were not observed after pretreatment with any of the polyhalogenated biphenyls studied. PMID:209992

Induction of Nrf2-mediated cellular defenses and alteration of phase I activities as mechanisms of chemoprotective effects of coffee in the liver.

Science.gov (United States)

Cavin, C; Marin-Kuan, M; Langouët, S; Bezençon, C; Guignard, G; Verguet, C; Piguet, D; Holzhäuser, D; Cornaz, R; Schilter, B

2008-04-01

Coffee consumption has been associated with a significant decrease in the risk of developing chronic diseases such as Parkinson disease, diabetes type-2 and several types of cancers (e.g. colon, liver). In the present study, a coffee-dependent induction of enzymes involved in xenobiotic detoxification processes was observed in rat liver and primary hepatocytes. In addition, coffee was found to induce the mRNA and protein expression of enzymes involved in cellular antioxidant defenses. These inductions were correlated with the activation of the Nrf2 transcription factor as shown using an ARE-reporter luciferase assay. The induction of detoxifying enzymes GSTs and AKR is compatible with a protection against both genotoxicity and cytotoxicity of aflatoxin B1 (AFB1). This hypothesis was confirmed in in vitro and ex vivo test systems, where coffee reduced both AFB1-DNA and protein adducts. Interestingly, coffee was also found to inhibit cytochrome CYP1A1/2, indicating that other mechanisms different from a stimulation of detoxification may also play a significant role in the chemoprotective effects of coffee. Further investigations in either human liver cell line and primary hepatocytes indicated that the chemoprotective effects of coffee against AFB1 genotoxicity are likely to be of relevance for humans. These data strongly suggest that coffee may protect against the adverse effects of AFB1. In addition, the coffee-mediated stimulation of the Nrf2-ARE pathway resulting in increased endogenous defense mechanisms against electrophilic but also oxidative insults further support that coffee may be associated with a protection against various types of chemical stresses.

Nanotechnology and nuclear medicine; research and preclinical applications.

Science.gov (United States)

Assadi, Majid; Afrasiabi, Kolsoom; Nabipour, Iraj; Seyedabadi, Mohammad

2011-01-01

The birth of nanotechnology in human society was around 2000 years ago and soon found applications in various fields. In this article, we highlight the current status of research and preclinical applications and also future prospects of nanotechnology in medicine and in nuclear medicine. The most important field is cancer. A regular nanotechnology training program for nuclear medicine physicians may be welcome.

Teacher induction

NARCIS (Netherlands)

Beijaard, D.; Buitink, J.; Kessels, C.; Peterson, P.; Baker, E.; McGraw, B.

2010-01-01

Teacher induction programs are intended to support the professional development of beginning teachers and thereby contribute to the reduction of teacher attrition during the early teaching years. Teacher induction programs are often based upon a deficit model with a focus on the better organization

TET1-Mediated Hydroxymethylation Facilitates Hypoxic Gene Induction in Neuroblastoma

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Christopher J. Mariani

2014-06-01

Full Text Available The ten-eleven-translocation 5-methylcytosine dioxygenase (TET family of enzymes catalyzes the conversion of 5-methylcytosine (5-mC to 5-hydroxymethylcytosine (5-hmC, a modified cytosine base that facilitates gene expression. Cells respond to hypoxia by inducing a transcriptional program regulated in part by oxygen-dependent dioxygenases that require Fe(II and α-ketoglutarate. Given that the TET enzymes also require these cofactors, we hypothesized that the TETs regulate the hypoxia-induced transcriptional program. Here, we demonstrate that hypoxia increases global 5-hmC levels, with accumulation of 5-hmC density at canonical hypoxia response genes. A subset of 5-hmC gains colocalize with hypoxia response elements facilitating DNA demethylation and HIF binding. Hypoxia results in transcriptional activation of TET1, and full induction of hypoxia-responsive genes and global 5-hmC increases require TET1. Finally, we show that 5-hmC increases and TET1 upregulation in hypoxia are HIF-1 dependent. These findings establish TET1-mediated 5-hmC changes as an important epigenetic component of the hypoxic response.

Phase II enzyme induction by a carotenoid, lutein, in a PC12D neuronal cell line

International Nuclear Information System (INIS)

Miyake, Seiji; Kobayashi, Saori; Tsubota, Kazuo; Ozawa, Yoko

2014-01-01

Highlights: • Lutein reduced ROS levels in a PC12D neuronal cell line. • Lutein induced mRNAs of phase II antioxidative enzymes in PC12D neuronal cells. • Lutein increased protein levels of HO-1, SOD2, and NQO-1 in PC12D neuronal cells. • Lutein had no effect on intranuclear Nrf2 levels in PC12D neuronal cells. • Lutein did not activate potential upstream Nrf2 nuclear translocation pathways. - Abstract: The mechanism by which lutein, a carotenoid, acts as an antioxidant in retinal cells is still not fully understood. Here, lutein treatment of a neuronal cell line (PC12D) immediately resulted in reduced intracellular ROS levels, implying that it has a direct role in ROS scavenging. Significantly, lutein treatment also induced phase II antioxidative enzyme expression, probably via a nuclear factor-like 2 (Nrf2) independent pathway. This latter mechanism could explain why lutein acts diversely to protect against oxidative/cytotoxic stress, and why it is physiologically involved in the human neural tissue, such as the retina

Phase II enzyme induction by a carotenoid, lutein, in a PC12D neuronal cell line

Energy Technology Data Exchange (ETDEWEB)

Miyake, Seiji [Laboratory of Retinal Cell Biology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Wakasa Seikatsu Co., Ltd., 134 Chudoujiminami-cho, Shimogyo-ku, Kyoto 600-8813 (Japan); Kobayashi, Saori [Wakasa Seikatsu Co., Ltd., 134 Chudoujiminami-cho, Shimogyo-ku, Kyoto 600-8813 (Japan); Tsubota, Kazuo [Laboratory of Retinal Cell Biology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Ozawa, Yoko, E-mail: ozawa@a5.keio.jp [Laboratory of Retinal Cell Biology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan)

2014-04-04

Highlights: • Lutein reduced ROS levels in a PC12D neuronal cell line. • Lutein induced mRNAs of phase II antioxidative enzymes in PC12D neuronal cells. • Lutein increased protein levels of HO-1, SOD2, and NQO-1 in PC12D neuronal cells. • Lutein had no effect on intranuclear Nrf2 levels in PC12D neuronal cells. • Lutein did not activate potential upstream Nrf2 nuclear translocation pathways. - Abstract: The mechanism by which lutein, a carotenoid, acts as an antioxidant in retinal cells is still not fully understood. Here, lutein treatment of a neuronal cell line (PC12D) immediately resulted in reduced intracellular ROS levels, implying that it has a direct role in ROS scavenging. Significantly, lutein treatment also induced phase II antioxidative enzyme expression, probably via a nuclear factor-like 2 (Nrf2) independent pathway. This latter mechanism could explain why lutein acts diversely to protect against oxidative/cytotoxic stress, and why it is physiologically involved in the human neural tissue, such as the retina.

Cognitive enhancers (nootropics). Part 2: drugs interacting with enzymes.

Science.gov (United States)

Froestl, Wolfgang; Muhs, Andreas; Pfeifer, Andrea

2013-01-01

Cognitive enhancers (nootropics) are drugs to treat cognition deficits in patients suffering from Alzheimer's disease, schizophrenia, stroke, attention deficit hyperactivity disorder, or aging. Cognition refers to a capacity for information processing, applying knowledge, and changing preferences. It involves memory, attention, executive functions, perception, language, and psychomotor functions. The term nootropics was coined in 1972 when memory enhancing properties of piracetam were observed in clinical trials. In the meantime, hundreds of drugs have been evaluated in clinical trials or in preclinical experiments. To classify the compounds, a concept is proposed assigning drugs to 19 categories according to their mechanism(s) of action, in particular drugs interacting with receptors, enzymes, ion channels, nerve growth factors, re-uptake transporters, antioxidants, metal chelators, and disease modifying drugs meaning small molecules, vaccines, and monoclonal antibodies interacting with amyloid-β and tau. For drugs whose mechanism of action is not known, they are either classified according to structure, e.g., peptides, or their origin, e.g., natural products. This review covers the evolution of research in this field over the last 25 years.

Mexican medicinal plants with anxiolytic or antidepressant activity: Focus on preclinical research.

Science.gov (United States)

López-Rubalcava, Carolina; Estrada-Camarena, Erika

2016-06-20

Anxiety and depression are considered the most prevalent psychiatric disorders worldwide. In Mexico, the use of medicinal plants to alleviate the symptoms associated with these psychiatric disorders is increasing. However, there is little scientific evidence that validates the efficacy of these plants. This evidence needs to be critically revised, and further studied to provided scientific support for their use. To identify the plants that are used in Mexico for the treatment of disorders related to anxiety and depression, and to review the current preclinical and when available, clinical information of these plants. We searched in scientific databases (Pubmed, Web of Science, Scopus and other web sources such as "Biblioteca digital de la medicina tradicional Mexicana" ) for Mexican plants used for the treatment of anxiety and depression that have been analyzed in preclinical studies. Additional information was obtained from published books. For this review, we also consider those plants used in Mexican traditional medicine for the treatment of "nervios," "susto" or "espanto;" common terms that describe symptoms related to anxiety and depression disorders. The bibliographic search identified 49 plants used in Mexican traditional medicine for the treatment of disorders related to anxiety and depression. From all these plants, 59% were analyzed in preclinical research, and only 8% were tested in clinical studies; only a few of these studies tried to elucidate their mechanism of action. In general, it is proposed that the plant extracts interact with the GABAergic system. However, only part of these studies attempted to analyze other neurotransmitter systems. Finally, in some cases, drug-herbal interactions were reported. There is a large number of Mexican medicinal plants used as a treatment for anxiety and depression disorders. Although some of these plants have been studied in preclinical research, in most cases these studies are preliminary, and the understanding

Cytochrome P450 induction by rifampicin in healthy subjects: determination using the Karolinska cocktail and the endogenous CYP3A4 marker 4beta-hydroxycholesterol.

Science.gov (United States)

Kanebratt, K P; Diczfalusy, U; Bäckström, T; Sparve, E; Bredberg, E; Böttiger, Y; Andersson, T B; Bertilsson, L

2008-11-01

The Karolinska cocktail, comprising caffeine, losartan, omeprazole, and quinine, was given before and after administration of rifampicin (20, 100, or 500 mg daily) to measure induction of cytochrome P450 (P450) enzymes. Rifampicin was given for 14 days to eight healthy subjects (all of whom possessed at least one wild-type CYP2C9 and one wild-type CYP2C19 gene) in each dose group. 4beta-hydroxycholesterol was assessed as an endogenous marker of CYP3A4 induction. A fourfold induction of CYP3A4 was seen at the highest dose by both quinine:3'-hydroxyquinine and 4beta-hydroxycholesterol measurements (P Karolinska cocktail and 4beta-hydroxycholesterol can be used for an initial screening of the induction properties of a drug candidate.

Pevonedistat, a first-in-class NEDD8-activating enzyme inhibitor, combined with azacitidine in patients with AML.

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Swords, Ronan T; Coutre, Steven; Maris, Michael B; Zeidner, Joshua F; Foran, James M; Cruz, Jose; Erba, Harry P; Berdeja, Jesus G; Tam, Wayne; Vardhanabhuti, Saran; Pawlikowska-Dobler, Iwona; Faessel, Hélène M; Dash, Ajeeta B; Sedarati, Farhad; Dezube, Bruce J; Faller, Douglas V; Savona, Michael R

2018-03-29

Pevonedistat (TAK-924/MLN4924) is a novel inhibitor of NEDD8-activating enzyme (NAE) with single-agent activity in relapsed/refractory acute myeloid leukemia (AML). We performed a phase 1b study of pevonedistat (PEV) with azacitidine (AZA) based on synergistic activity seen preclinically. Primary objectives included safety and tolerability, and secondary objectives included pharmacokinetics (PK) and disease response. Patients ≥60 years with treatment-naive AML (unfit for standard induction therapy) received PEV 20 or 30 mg/m 2 IV on days 1, 3, and 5 combined with fixed-dose AZA (75 mg/m 2 IV/subcutaneously) on days 1 to 5, 8, and 9, every 28 days. The most common treatment-emergent adverse events were constipation (48%), nausea (42%), fatigue (42%), and anemia (39%). In total, 11 deaths were observed and considered unrelated to study therapy by the investigators. Transient elevations in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were dose limiting. The recommended phase 2 dose (RP2D) of PEV in this combination is 20 mg/m 2 PEV PK was not altered by the addition of AZA. Overall response rate (ORR) based on an intent-to-treat analysis was 50% (20 complete remissions [CRs], 5 complete remission with incomplete peripheral count recovery, 7 partial remissions [PRs]), with an 8.3-month median duration of remission. In patients receiving ≥6 cycles of therapy (n = 23, 44%), ORR was 83%. In patients with TP53 mutations, the composite CR/PR rate was 80% (4/5). Two of these patients stayed on study for >10 cycles. Baseline bone marrow blast percentage or cytogenetic/molecular risk did not influence ORR. This study was registered at www.clinicaltrials.gov as #NCT01814826. © 2018 by The American Society of Hematology.

Small Molecular TRAIL Inducer ONC201 Induces Death in Lung Cancer Cells: A Preclinical Study.

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Feng, Yuan; Zhou, Jihong; Li, Zhanhua; Jiang, Ying; Zhou, Ying

2016-01-01

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) selectively targets cancer cells. The present preclinical study investigated the anti-cancer efficiency of ONC201, a first-in-class small molecule TRAIL inducer, in lung cancer cells. We showed that ONC201 was cytotoxic and anti-proliferative in both established (A549 and H460 lines) and primary human lung cancer cells. It was yet non-cytotoxic to normal lung epithelial cells. Further, ONC201 induced exogenous apoptosis activation in lung cancer cells, which was evidenced by TRAIL/death receptor-5 (DR5) induction and caspase-8 activation. The caspase-8 inhibitor or TRAIL/DR5 siRNA knockdown alleviated ONC201's cytotoxicity against lung cancer cells. Molecularly, ONC201 in-activated Akt-S6K1 and Erk signalings in lung cancer cells, causing Foxo3a nuclear translocation. For the in vivo studies, intraperitoneal injection of ONC201 at well-tolerated doses significantly inhibited xenografted A549 tumor growth in severe combined immunodeficient (SCID) mice. Further, ONC201 administration induced TRAIL/DR5 expression, yet inactivated Akt-S6K1 and Erk in tumor tissues. These results of the study demonstrates the potent anti-lung cancer activity by ONC201.

Small Molecular TRAIL Inducer ONC201 Induces Death in Lung Cancer Cells: A Preclinical Study.

Directory of Open Access Journals (Sweden)

Yuan Feng

Full Text Available Tumor necrosis factor (TNF-related apoptosis-inducing ligand (TRAIL selectively targets cancer cells. The present preclinical study investigated the anti-cancer efficiency of ONC201, a first-in-class small molecule TRAIL inducer, in lung cancer cells. We showed that ONC201 was cytotoxic and anti-proliferative in both established (A549 and H460 lines and primary human lung cancer cells. It was yet non-cytotoxic to normal lung epithelial cells. Further, ONC201 induced exogenous apoptosis activation in lung cancer cells, which was evidenced by TRAIL/death receptor-5 (DR5 induction and caspase-8 activation. The caspase-8 inhibitor or TRAIL/DR5 siRNA knockdown alleviated ONC201's cytotoxicity against lung cancer cells. Molecularly, ONC201 in-activated Akt-S6K1 and Erk signalings in lung cancer cells, causing Foxo3a nuclear translocation. For the in vivo studies, intraperitoneal injection of ONC201 at well-tolerated doses significantly inhibited xenografted A549 tumor growth in severe combined immunodeficient (SCID mice. Further, ONC201 administration induced TRAIL/DR5 expression, yet inactivated Akt-S6K1 and Erk in tumor tissues. These results of the study demonstrates the potent anti-lung cancer activity by ONC201.

Preclinical stress research: where are we headed? An early career investigator's perspective.

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Gururajan, Anand; Kos, Aron; Lopez, Juan Pablo

2018-03-07

Stress is a major risk factor in the development of various psychiatric disorders such as depression, anxiety and post-traumatic stress disorder. The use of stress paradigms in preclinical contexts is essential to advance our understanding of the pathophysiology of these disorders. However, they are not without their limitations and in this commentary, we have examined some of the practical issues associated with their use. We also highlight some of the latest techniques to identify their neuromolecular correlates as well as the potentially important and integrative role of computational neuroscience. Finally, we share our perspective on future directions in the field of preclinical stress research.

Preclinical antivenom-efficacy testing reveals potentially disturbing deficiencies of snakebite treatment capability in East Africa.

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Robert A Harrison

2017-10-01

Full Text Available Antivenom is the treatment of choice for snakebite, which annually kills an estimated 32,000 people in sub-Saharan Africa and leaves approximately 100,000 survivors with permanent physical disabilities that exert a considerable socioeconomic burden. Over the past two decades, the high costs of the most polyspecifically-effective antivenoms have sequentially reduced demand, commercial manufacturing incentives and production volumes that have combined to create a continent-wide vacuum of effective snakebite therapy. This was quickly filled with new, less expensive antivenoms, many of which are of untested efficacy. Some of these successfully marketed antivenoms for Africa are inappropriately manufactured with venoms from non-African snakes and are dangerously ineffective. The uncertain efficacy of available antivenoms exacerbates the complexity of designing intervention measures to reduce the burden of snakebite in sub-Saharan Africa. The objective of this study was to preclinically determine the ability of antivenoms available in Kenya to neutralise the lethal effects of venoms from the most medically important snakes in East Africa.We collected venom samples from the most medically important snakes in East Africa and determined their toxicity in a mouse model. Using a 'gold standard' comparison protocol, we preclinically tested the comparative venom-neutralising efficacy of four antivenoms available in Kenya with two antivenoms of clinically-proven efficacy. To explain the variant efficacies of these antivenoms we tested the IgG-venom binding characteristics of each antivenom using in vitro IgG titre, avidity and venom-protein specificity assays. We also measured the IgG concentration of each antivenom.None of the six antivenoms are preclinically effective, at the doses tested, against all of the most medically important snakes of the region. The very limited snake polyspecific efficacy of two locally available antivenoms is of concern. In vitro

Enzyme Informatics

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Alderson, Rosanna G.; Ferrari, Luna De; Mavridis, Lazaros; McDonagh, James L.; Mitchell, John B. O.; Nath, Neetika

2012-01-01

Over the last 50 years, sequencing, structural biology and bioinformatics have completely revolutionised biomolecular science, with millions of sequences and tens of thousands of three dimensional structures becoming available. The bioinformatics of enzymes is well served by, mostly free, online databases. BRENDA describes the chemistry, substrate specificity, kinetics, preparation and biological sources of enzymes, while KEGG is valuable for understanding enzymes and metabolic pathways. EzCatDB, SFLD and MACiE are key repositories for data on the chemical mechanisms by which enzymes operate. At the current rate of genome sequencing and manual annotation, human curation will never finish the functional annotation of the ever-expanding list of known enzymes. Hence there is an increasing need for automated annotation, though it is not yet widespread for enzyme data. In contrast, functional ontologies such as the Gene Ontology already profit from automation. Despite our growing understanding of enzyme structure and dynamics, we are only beginning to be able to design novel enzymes. One can now begin to trace the functional evolution of enzymes using phylogenetics. The ability of enzymes to perform secondary functions, albeit relatively inefficiently, gives clues as to how enzyme function evolves. Substrate promiscuity in enzymes is one example of imperfect specificity in protein-ligand interactions. Similarly, most drugs bind to more than one protein target. This may sometimes result in helpful polypharmacology as a drug modulates plural targets, but also often leads to adverse side-effects. Many cheminformatics approaches can be used to model the interactions between druglike molecules and proteins in silico. We can even use quantum chemical techniques like DFT and QM/MM to compute the structural and energetic course of enzyme catalysed chemical reaction mechanisms, including a full description of bond making and breaking. PMID:23116471

Induction heating using induction coils in series-parallel circuits

Science.gov (United States)

Matsen, Marc Rollo; Geren, William Preston; Miller, Robert James; Negley, Mark Alan; Dykstra, William Chet

2017-11-14

A part is inductively heated by multiple, self-regulating induction coil circuits having susceptors, coupled together in parallel and in series with an AC power supply. Each of the circuits includes a tuning capacitor that tunes the circuit to resonate at the frequency of AC power supply.

Myocardial infarction in pregnancy associated with clomiphene citrate for ovulation induction: a case report.

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Duran, J Roberto; Raja, Mohammed L

2007-11-01

Clomiphene citrate (CC) is commonly prescribed for ovulation induction. It is considered safe, with minimal side effects. Thromboembolism is a rare but life-threatening complication that has been reported after ovulation induction with CC. Spontaneous coronary thrombosis or thromboembolism with subsequent clot lysis has been suggested as one of the most common causes of myocardial infarction (MI) during pregnancy, with a subsequently normal coronary angiogram. A 33-year-old woman with a 5-week gestation had recently received CC for ovulation induction and presented with chest pain. An electrocardiogram showed a lateral and anterior wall myocardial infarction. Cardiac enzymes showed a peak rise in troponin I to 9.10 ng/mL. An initial exercise stress test was normal. At the time of admission, the patient was at high risk of radiation injury to the fetus, so a coronary angiogram was postponed until the second trimester. It showed normal coronary vessels. This appears to be the first reported case documenting a possible association between CC and myocardial infarction. Thrombosis might be a rare but hazardous complication of CC. Given this life-threatening complication, appropriate prophylactic measures should be used in high-risk woman undergoing ovarian stimulation.

Impact of diet restriction in the management of diabetes: evidences from preclinical studies.

Science.gov (United States)

Krishan, Pawan; Bedi, Onkar; Rani, Monika

2018-03-01

The inappropriate dietary habits lead to the onset of age-related pathologies which include diabetes and cardiovascular ailments. Dietary restriction and nutritional therapy play an important role in the prevention of these chronic ailments. Preclinical research provides a basis for the therapeutic exploration of new dietary interventions for the clinical trials to potentiate the scientific management of diabetes and its related complications which further help in translating these nutritional improvements from bench to bedside. Within the same context, numerous therapeutically proved preclinical dietary interventions like high-fiber diet, caloric restriction, soy isoflavone-containing diets, etc., have shown the promising results for the management of diabetes and the associated complications. The focus of the present review is to highlight the various preclinical evidences of diet restriction for the management of diabetes and which will be helpful for enlightening the new ideas of nutritional therapy for future research exploration. In addition, some potential approaches are also discussed which are associated with various nutritional interventions to combat progressive diabetes and the associated disorders. Graphical abstract ᅟ.

Modulation of Xenobiotic Metabolizing Enzyme and Transporter Gene Expression in Primary Cultures of Human Hepatocytes by ToxCast Chemicals

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ToxCast chemicals were assessed for induction or suppression of xenobiotic metabolizing enzyme and transporter gene expression using primary human hepatocytes. The mRNA levels of 14 target and 2 control genes were measured: ABCB1, ABCB11, ABCG2, SLCO1B1, CYP1A1, CYP1A2, CYP2B6, C...

A Flexible, Preclinical, Medical School Curriculum Increases Student Academic Productivity and the Desire to Conduct Future Research

Science.gov (United States)

Peacock, Justin G.; Grande, Joseph P.

2015-01-01

In 2006, small blocks of flexible curriculum time, termed selectives, were implemented in the Mayo Medical School preclinical curriculum. Selectives permitted students to pursue professional endeavors, such as research, service, and career exploration, in the preclinical years. The purpose of this study was to survey current and former Mayo…

Application of forgetful analgesia induction in induction period in patients with obstructive jaundice

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Wei DU

2014-03-01

Full Text Available Objective　To observe the effect of forgetful analgesia induction and tracheal intubation on the hemodynamic changes in induction period in patients with obstructive jaundice, and explore a safe method for anesthesia induction and tracheal intubation. Methods　Sixty patients with obstructive jaundice undergoing elective abdominal operation in General Hospital of PLA from February, 2013 to August, 2013 were involved in the present study. Participants included 36 male and 24 female patients, aging 19-65 years (mean 42±5 years, weighing 47-73 kg (mean 54±6 kg, with ASA Ⅰ-Ⅱ. These 60 patients were randomly divided into forgetful analgesia induction-tracheal intubation group (group A, n=30 and rapid induction-tracheal intubation group (group B, n=30. The heart rate (HR, mean arterial pressure (MAP, pulse oxygen saturation (SpO2 at the time point of before induction (T0, before intubation (T1, at the moment of intubation (T2 and 3 min after intubation (T3 were determined in both groups. Administration times of ephedrine hydrochloride and atropine was recorded in both groups. Results　There was no significant difference in HR, MAP, SpO2 before and after induction in group A. In the patients of group B, the HR increased and MAP decreased after induction compared with those before induction (P<0.05, and the change of SpO2 was not significant. Ephedrine hydrochloride and atropine were administrated in both groups, and the cases and times of ephedrine hydrochloride administration were more in group B than in group A (P<0.05. Conclusion　The forgetful analgesia induction-tracheal intubation could effectively control the stress response and reduce the fluctuation in hemodynamics during induction of anesthesia in patients with obstructive jaundice. DOI: 10.11855/j.issn.0577-7402.2014.02.15

Preliminary study for small animal preclinical hadrontherapy facility

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Russo, G. [Institute of Molecular Bioimaging and Physiology, IBFM CNR-LATO, Cefalú (Italy); Pisciotta, P., E-mail: pietro.pisciotta@ibfm.cnr.it [Institute of Molecular Bioimaging and Physiology, IBFM CNR-LATO, Cefalú (Italy); National Institute for Nuclear Physics, Laboratori Nazionali del Sud, INFN-LNS, Catania (Italy); Cirrone, G.A.P.; Romano, F. [National Institute for Nuclear Physics, Laboratori Nazionali del Sud, INFN-LNS, Catania (Italy); Cammarata, F.; Marchese, V.; Forte, G.I.; Lamia, D.; Minafra, L.; Bravatá, V. [Institute of Molecular Bioimaging and Physiology, IBFM CNR-LATO, Cefalú (Italy); Acquaviva, R. [University of Catania, Catania (Italy); Gilardi, M.C. [Institute of Molecular Bioimaging and Physiology, IBFM CNR-LATO, Cefalú (Italy); Cuttone, G. [National Institute for Nuclear Physics, Laboratori Nazionali del Sud, INFN-LNS, Catania (Italy)

2017-02-21

Aim of this work is the study of the preliminary steps to perform a particle treatment of cancer cells inoculated in small animals and to realize a preclinical hadrontherapy facility. A well-defined dosimetric protocol was developed to explicate the steps needed in order to perform a precise proton irradiation in small animals and achieve a highly conformal dose into the target. A precise homemade positioning and holding system for small animals was designed and developed at INFN-LNS in Catania (Italy), where an accurate Monte Carlo simulation was developed, using Geant4 code to simulate the treatment in order to choose the best animal position and perform accurately all the necessary dosimetric evaluations. The Geant4 application can also be used to realize dosimetric studies and its peculiarity consists in the possibility to introduce the real target composition in the simulation using the DICOM micro-CT image. This application was fully validated comparing the results with the experimental measurements. The latter ones were performed at the CATANA (Centro di AdroTerapia e Applicazioni Nucleari Avanzate) facility at INFN-LNS by irradiating both PMMA and water solid phantom. Dosimetric measurements were performed using previously calibrated EBT3 Gafchromic films as a detector and the results were compared with the Geant4 simulation ones. In particular, two different types of dosimetric studies were performed: the first one involved irradiation of a phantom made up of water solid slabs where a layer of EBT3 was alternated with two different slabs in a sandwich configuration, in order to validate the dosimetric distribution. The second one involved irradiation of a PMMA phantom made up of a half hemisphere and some PMMA slabs in order to simulate a subcutaneous tumour configuration, normally used in preclinical studies. In order to evaluate the accordance between experimental and simulation results, two different statistical tests were made: Kolmogorov test and

Preliminary study for small animal preclinical hadrontherapy facility

Science.gov (United States)

Russo, G.; Pisciotta, P.; Cirrone, G. A. P.; Romano, F.; Cammarata, F.; Marchese, V.; Forte, G. I.; Lamia, D.; Minafra, L.; Bravatá, V.; Acquaviva, R.; Gilardi, M. C.; Cuttone, G.

2017-02-01

Aim of this work is the study of the preliminary steps to perform a particle treatment of cancer cells inoculated in small animals and to realize a preclinical hadrontherapy facility. A well-defined dosimetric protocol was developed to explicate the steps needed in order to perform a precise proton irradiation in small animals and achieve a highly conformal dose into the target. A precise homemade positioning and holding system for small animals was designed and developed at INFN-LNS in Catania (Italy), where an accurate Monte Carlo simulation was developed, using Geant4 code to simulate the treatment in order to choose the best animal position and perform accurately all the necessary dosimetric evaluations. The Geant4 application can also be used to realize dosimetric studies and its peculiarity consists in the possibility to introduce the real target composition in the simulation using the DICOM micro-CT image. This application was fully validated comparing the results with the experimental measurements. The latter ones were performed at the CATANA (Centro di AdroTerapia e Applicazioni Nucleari Avanzate) facility at INFN-LNS by irradiating both PMMA and water solid phantom. Dosimetric measurements were performed using previously calibrated EBT3 Gafchromic films as a detector and the results were compared with the Geant4 simulation ones. In particular, two different types of dosimetric studies were performed: the first one involved irradiation of a phantom made up of water solid slabs where a layer of EBT3 was alternated with two different slabs in a sandwich configuration, in order to validate the dosimetric distribution. The second one involved irradiation of a PMMA phantom made up of a half hemisphere and some PMMA slabs in order to simulate a subcutaneous tumour configuration, normally used in preclinical studies. In order to evaluate the accordance between experimental and simulation results, two different statistical tests were made: Kolmogorov test and

Preliminary study for small animal preclinical hadrontherapy facility

International Nuclear Information System (INIS)

Russo, G.; Pisciotta, P.; Cirrone, G.A.P.; Romano, F.; Cammarata, F.; Marchese, V.; Forte, G.I.; Lamia, D.; Minafra, L.; Bravatá, V.; Acquaviva, R.; Gilardi, M.C.; Cuttone, G.

2017-01-01

Aim of this work is the study of the preliminary steps to perform a particle treatment of cancer cells inoculated in small animals and to realize a preclinical hadrontherapy facility. A well-defined dosimetric protocol was developed to explicate the steps needed in order to perform a precise proton irradiation in small animals and achieve a highly conformal dose into the target. A precise homemade positioning and holding system for small animals was designed and developed at INFN-LNS in Catania (Italy), where an accurate Monte Carlo simulation was developed, using Geant4 code to simulate the treatment in order to choose the best animal position and perform accurately all the necessary dosimetric evaluations. The Geant4 application can also be used to realize dosimetric studies and its peculiarity consists in the possibility to introduce the real target composition in the simulation using the DICOM micro-CT image. This application was fully validated comparing the results with the experimental measurements. The latter ones were performed at the CATANA (Centro di AdroTerapia e Applicazioni Nucleari Avanzate) facility at INFN-LNS by irradiating both PMMA and water solid phantom. Dosimetric measurements were performed using previously calibrated EBT3 Gafchromic films as a detector and the results were compared with the Geant4 simulation ones. In particular, two different types of dosimetric studies were performed: the first one involved irradiation of a phantom made up of water solid slabs where a layer of EBT3 was alternated with two different slabs in a sandwich configuration, in order to validate the dosimetric distribution. The second one involved irradiation of a PMMA phantom made up of a half hemisphere and some PMMA slabs in order to simulate a subcutaneous tumour configuration, normally used in preclinical studies. In order to evaluate the accordance between experimental and simulation results, two different statistical tests were made: Kolmogorov test and

Ensuring transparency and minimization of methodologic bias in preclinical pain research: PPRECISE considerations.

Science.gov (United States)

Andrews, Nick A; Latrémolière, Alban; Basbaum, Allan I; Mogil, Jeffrey S; Porreca, Frank; Rice, Andrew S C; Woolf, Clifford J; Currie, Gillian L; Dworkin, Robert H; Eisenach, James C; Evans, Scott; Gewandter, Jennifer S; Gover, Tony D; Handwerker, Hermann; Huang, Wenlong; Iyengar, Smriti; Jensen, Mark P; Kennedy, Jeffrey D; Lee, Nancy; Levine, Jon; Lidster, Katie; Machin, Ian; McDermott, Michael P; McMahon, Stephen B; Price, Theodore J; Ross, Sarah E; Scherrer, Grégory; Seal, Rebecca P; Sena, Emily S; Silva, Elizabeth; Stone, Laura; Svensson, Camilla I; Turk, Dennis C; Whiteside, Garth

2016-04-01

There is growing concern about lack of scientific rigor and transparent reporting across many preclinical fields of biological research. Poor experimental design and lack of transparent reporting can result in conscious or unconscious experimental bias, producing results that are not replicable. The Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership with the U.S. Food and Drug Administration sponsored a consensus meeting of the Preclinical Pain Research Consortium for Investigating Safety and Efficacy (PPRECISE) Working Group. International participants from universities, funding agencies, government agencies, industry, and a patient advocacy organization attended. Reduction of publication bias, increasing the ability of others to faithfully repeat experimental methods, and increased transparency of data reporting were specifically discussed. Parameters deemed essential to increase confidence in the published literature were clear, specific reporting of an a priori hypothesis and definition of primary outcome measure. Power calculations and whether measurement of minimal meaningful effect size to determine these should be a core component of the preclinical research effort provoked considerable discussion, with many but not all agreeing. Greater transparency of reporting should be driven by scientists, journal editors, reviewers, and grant funders. The conduct of high-quality science that is fully reported should not preclude novelty and innovation in preclinical pain research, and indeed, any efforts that curtail such innovation would be misguided. We believe that to achieve the goal of finding effective new treatments for patients with pain, the pain field needs to deal with these challenging issues.

The effect of learning styles and study behavior on success of preclinical students in pharmacology.

Science.gov (United States)

Asci, Halil; Kulac, Esin; Sezik, Mekin; Cankara, F Nihan; Cicek, Ekrem

2016-01-01

To evaluate the effect of learning styles and study behaviors on preclinical medical students' pharmacology exam scores in a non-Western setting. Grasha-Reichmann Student Learning Study Scale and a modified Study Behavior Inventory were used to assess learning styles and study behaviors of preclinical medical students (n = 87). Logistic regression models were used to evaluate the independent effect of gender, age, learning style, and study behavior on pharmacology success. Collaborative (40%) and competitive (27%) dominant learning styles were frequent in the cohort. The most common study behavior subcategories were study reading (40%) and general study habits (38%). Adequate listening and note-taking skills were associated with pharmacology success, whereas students with adequate writing skills had lower exam scores. These effects were independent of gender. Preclinical medical students' study behaviors are independent predictive factors for short-term pharmacology success.

Manufacture of Third-Generation Lentivirus for Preclinical Use, with Process Development Considerations for Translation to Good Manufacturing Practice.

Science.gov (United States)

Gándara, Carolina; Affleck, Valerie; Stoll, Elizabeth Ann

2018-02-01

Lentiviral vectors are used in laboratories around the world for in vivo and ex vivo delivery of gene therapies, and increasingly clinical investigation as well as preclinical applications. The third-generation lentiviral vector system has many advantages, including high packaging capacity, stable gene expression in both dividing and post-mitotic cells, and low immunogenicity in the recipient organism. Yet, the manufacture of these vectors is challenging, especially at high titers required for direct use in vivo, and further challenges are presented by the process of translating preclinical gene therapies toward manufacture of products for clinical investigation. The goals of this paper are to report the protocol for manufacturing high-titer third-generation lentivirus for preclinical testing and to provide detailed information on considerations for translating preclinical viral vector manufacture toward scaled-up platforms and processes in order to make gene therapies under Good Manufacturing Practice that are suitable for clinical trials.

Jasmonate is involved in the induction of tyrosine aminotransferase and tocopherol biosynthesis in Arabidopsis thaliana.

Science.gov (United States)

Sandorf, Iris; Holländer-Czytko, Heike

2002-11-01

Coronatine-inducible tyrosine aminotransferase (TAT), which catalyses the transamination from tyrosine to p-hydroxyphenylpyruvate, is the first enzyme of a pathway leading via homogentisic acid to plastoquinone and tocopherols, the latter of which are known to be radical scavengers in plants. TAT can be also induced by the octadecanoids methyl jasmonate (MeJA) and methyl-12-oxophytodienoic acid (MeOPDA), as well as by wounding, high light, UV light and the herbicide oxyfluorfen. In order to elucidate the role of octadecanoids in the process of TAT induction in Arabidopsis thaliana (L.) Heynh., the jasmonate-deficient mutant delayed dehiscence (dde1) was used, in which the gene for 12-oxophytodienoic acid reductase 3 is disrupted. The amount of immunodetectable TAT was low. The enzyme was still fully induced by coronatine as well as by MeJA although induction by the latter was to a lesser extent and later than in the wild type. Treatment with MeOPDA, wounding and UV light, however, had hardly any effects. Tocopherol levels that showed considerable increases in the wild type after some treatments were much less affected in the mutant. However, starting levels of tocopherol were higher in non-induced dde1 than in the wild type. We conclude that jasmonate plays an important role in the signal transduction pathway regulating TAT activity and the biosynthesis of its product tocopherol.

A preclinical mouse model of invasive lobular breast cancer metastasis

NARCIS (Netherlands)

Doornebal, Chris W.; Klarenbeek, Sjoerd; Braumuller, Tanya M.; Klijn, Christiaan N.; Ciampricotti, Metamia; Hau, Cheei-Sing; Hollmann, Markus W.; Jonkers, Jos; de Visser, Karin E.

2013-01-01

Metastatic disease accounts for more than 90% of cancer-related deaths, but the development of effective antimetastatic agents has been hampered by the paucity of clinically relevant preclinical models of human metastatic disease. Here, we report the development of a mouse model of spontaneous

Altered whole-brain white matter networks in preclinical Alzheimer's disease

Directory of Open Access Journals (Sweden)

Florian Udo Fischer

2015-01-01

Our results suggest an impairment of WM networks in preclinical AD that is detectable while other structural imaging markers do not yet indicate incipient neurodegeneration. Moreover, these findings are specific to WM networks and cannot be explained by other surrogates of global WM integrity.

Enzyme induction and cytotoxicity in human hepatocytes by chlorpyrifos and N,N-diethyl-m-toluamide (DEET).

Science.gov (United States)

Das, Parikshit C; Cao, Yan; Rose, Randy L; Cherrington, Nathan; Hodgson, Ernest

2008-01-01

Xenobiotics, including drugs and environmental chemicals, can influence cytochrome P450 (CYP) levels by altering the transcription of CYP genes. To minimize potential drug-pesticide and pesticide-pesticide interactions it is important to evaluate the potential of pesticides to induce CYP isoforms and to cause cytotoxicity in humans. The present study was designed to examine chlorpyrifos and DEET mediated induction of CYP isoforms and also to characterize their potential cytotoxic effects on primary human hepatocytes. DEET significantly induced CYP3A4, CYP2B6, CYP2A6 and CYP1A2 mRNA expression while chlorpyrifos induced CYP1A1, CYP1A2 and CYP3A4 mRNA, and to a lesser extent, CYP1B1 and CYP2B6 mRNA in primary human hepatocytes. Chlorpyrifos and DEET also mediated the expression of CYP isoforms, particularly CYP3A4, CYP2B6 and CYP1A1, as shown by CYP3A4-specific protein expression, testosterone metabolism and CYP1Al-specific activity assays. DEET is a mild, while chlorpyrifos is a relatively potent, inducer of adenylate kinase and caspase-3/7, an indicator of apoptosis, while inducing 15-20% and 25-30% cell death, respectively. Therefore, DEET and chlorpyrifos mediated induction of CYP mRNA and functional CYP isoforms together with their cytotoxic potential in human hepatocytes suggests that exposure to chlorpyrifos and/or DEET should be considered in human health impact analysis.

Induction of c-Jun by air particulate matter (PM₁₀) of Mexico city: Participation of polycyclic aromatic hydrocarbons.

Science.gov (United States)

Salcido-Neyoy, Martha Estela; Sánchez-Pérez, Yesennia; Osornio-Vargas, Alvaro Román; Gonsebatt, María Eugenia; Meléndez-Zajgla, Jorge; Morales-Bárcenas, Rocío; Petrosyan, Pavel; Molina-Servin, Edith Danny; Vega, Elizabeth; Manzano-León, Natalia; García-Cuellar, Claudia M

2015-08-01

The carcinogenic potential of urban particulate matter (PM) has been partly attributed to polycyclic aromatic hydrocarbons (PAHs) content, which activates the aryl hydrocarbon receptor (AhR). Here we report the effect of PM with an aerodynamic size of 10 μm (PM10) on the induction of AhR pathway in A549 cells, evaluating its downstream targets CYP1B1, IL-6, IL-8 and c-Jun. Significant increases in CYP1B1 protein and enzyme activity; IL-6 and IL-8 secretion and c-Jun protein were found in response to PM10. The formation of PAH-DNA adducts was also detected. The involvement of AhR pathway was confirmed with Resveratrol as AhR antagonist, which reversed CYP1B1 and c-Jun induction. Nevertheless, in IL-6 and IL-8 secretion, the Resveratrol was ineffective, suggesting an effect independent of this pathway. Considering the role of c-Jun in oncogenesis, its induction by PM may be contributing to its carcinogenic potential through induction of AhR pathway by PAHs present in PM10. Copyright © 2015 Elsevier Ltd. All rights reserved.

Stem Cells for Cartilage Repair: Preclinical Studies and Insights in Translational Animal Models and Outcome Measures

Directory of Open Access Journals (Sweden)

Melissa Lo Monaco

2018-01-01

Full Text Available Due to the restricted intrinsic capacity of resident chondrocytes to regenerate the lost cartilage postinjury, stem cell-based therapies have been proposed as a novel therapeutic approach for cartilage repair. Moreover, stem cell-based therapies using mesenchymal stem cells (MSCs or induced pluripotent stem cells (iPSCs have been used successfully in preclinical and clinical settings. Despite these promising reports, the exact mechanisms underlying stem cell-mediated cartilage repair remain uncertain. Stem cells can contribute to cartilage repair via chondrogenic differentiation, via immunomodulation, or by the production of paracrine factors and extracellular vesicles. But before novel cell-based therapies for cartilage repair can be introduced into the clinic, rigorous testing in preclinical animal models is required. Preclinical models used in regenerative cartilage studies include murine, lapine, caprine, ovine, porcine, canine, and equine models, each associated with its specific advantages and limitations. This review presents a summary of recent in vitro data and from in vivo preclinical studies justifying the use of MSCs and iPSCs in cartilage tissue engineering. Moreover, the advantages and disadvantages of utilizing small and large animals will be discussed, while also describing suitable outcome measures for evaluating cartilage repair.

Stem Cells for Cartilage Repair: Preclinical Studies and Insights in Translational Animal Models and Outcome Measures.

Science.gov (United States)

Lo Monaco, Melissa; Merckx, Greet; Ratajczak, Jessica; Gervois, Pascal; Hilkens, Petra; Clegg, Peter; Bronckaers, Annelies; Vandeweerd, Jean-Michel; Lambrichts, Ivo

2018-01-01

Due to the restricted intrinsic capacity of resident chondrocytes to regenerate the lost cartilage postinjury, stem cell-based therapies have been proposed as a novel therapeutic approach for cartilage repair. Moreover, stem cell-based therapies using mesenchymal stem cells (MSCs) or induced pluripotent stem cells (iPSCs) have been used successfully in preclinical and clinical settings. Despite these promising reports, the exact mechanisms underlying stem cell-mediated cartilage repair remain uncertain. Stem cells can contribute to cartilage repair via chondrogenic differentiation, via immunomodulation, or by the production of paracrine factors and extracellular vesicles. But before novel cell-based therapies for cartilage repair can be introduced into the clinic, rigorous testing in preclinical animal models is required. Preclinical models used in regenerative cartilage studies include murine, lapine, caprine, ovine, porcine, canine, and equine models, each associated with its specific advantages and limitations. This review presents a summary of recent in vitro data and from in vivo preclinical studies justifying the use of MSCs and iPSCs in cartilage tissue engineering. Moreover, the advantages and disadvantages of utilizing small and large animals will be discussed, while also describing suitable outcome measures for evaluating cartilage repair.

Studies on in vitro induction mutation for wheat mutant of resistance to root rot and its resistance mechanism

International Nuclear Information System (INIS)

Sun Guangzu

1992-06-01

The screening wheat mutant which has the resistance to root rot was completed in 37 varieties by in vitro induction mutation method. The effect of irradiation on in vitro culture of different wheat explants and the effectiveness of screening rude toxin were studied. Two wheat mutants, RB500 and RB501, which have the resistance to root rot, were obtained. Changes of the ultrastructure and defensive enzymes (SOD, ROD and PAL) were investigated by using mutants and parent under the action of rude toxin. The results showed that the rude toxin could induce changes of enzyme activity, isoenzyme pattern and ultrastructure of the mitochondria and chloroplast. These change correspond to their ability of resistance to disease. The mutant under the action of toxin has the ability to increase the defensive enzyme activity and to reduce the damage of cell membrane system that would result in resistance increasing

Induction of anthocyanin formation and of enzymes related to its biosynthesis by UV light in cell cultures of Haplopappus gracilis

International Nuclear Information System (INIS)

Wellmann, E.; Hrazdina, G.; Grisebach, H.

1976-01-01

Only UV light below 345 nm stimulates anthocyanin formation in dark grown cell suspension cultures of Haplopappus gracilis. A linear relationship between UV dose and flavonoid accumulation, as found previously with parsley cell cultures was not observed with the H.gracilis cells. Only continuous irradiation with high doses of UV was effective. Drastic increases in the activities of the enzymes phenylalanine ammonia-lyase, chalcone isomerase and flavanone synthase were observed under continuous UV light. The increase in enzyme activities paralleled anthocyanin formation. (author)

Combination Therapy with NHS-muIL12 and Avelumab (anti-PD-L1) Enhances Antitumor Efficacy in Preclinical Cancer Models.

Science.gov (United States)

Xu, Chunxiao; Zhang, Yanping; Rolfe, P Alexander; Hernández, Vivian M; Guzman, Wilson; Kradjian, Giorgio; Marelli, Bo; Qin, Guozhong; Qi, Jin; Wang, Hong; Yu, Huakui; Tighe, Robert; Lo, Kin-Ming; English, Jessie M; Radvanyi, Laszlo; Lan, Yan

2017-10-01

Purpose: To determine whether combination therapy with NHS-muIL12 and the anti-programmed death ligand 1 (PD-L1) antibody avelumab can enhance antitumor efficacy in preclinical models relative to monotherapies. Experimental Design: BALB/c mice bearing orthotopic EMT-6 mammary tumors and μMt - mice bearing subcutaneous MC38 tumors were treated with NHS-muIL12, avelumab, or combination therapy; tumor growth and survival were assessed. Tumor recurrence following remission and rechallenge was evaluated in EMT-6 tumor-bearing mice. Immune cell populations within spleen and tumors were evaluated by FACS and IHC. Immune gene expression in tumor tissue was profiled by NanoString® assay and plasma cytokine levels were determined by multiplex cytokine assay. The frequency of tumor antigen-reactive IFNγ-producing CD8 + T cells was evaluated by ELISpot assay. Results: NHS-muIL12 and avelumab combination therapy enhanced antitumor efficacy relative to either monotherapy in both tumor models. Most EMT-6 tumor-bearing mice treated with combination therapy had complete tumor regression. Combination therapy also induced the generation of tumor-specific immune memory, as demonstrated by protection against tumor rechallenge and induction of effector and memory T cells. Combination therapy enhanced cytotoxic NK and CD8 + T-cell proliferation and T-bet expression, whereas NHS-muIL12 monotherapy induced CD8 + T-cell infiltration into the tumor. Combination therapy also enhanced plasma cytokine levels and stimulated expression of a greater number of innate and adaptive immune genes compared with either monotherapy. Conclusions: These data indicate that combination therapy with NHS-muIL12 and avelumab increased antitumor efficacy in preclinical models, and suggest that combining NHS-IL12 and avelumab may be a promising approach to treating patients with solid tumors. Clin Cancer Res; 23(19); 5869-80. ©2017 AACR . ©2017 American Association for Cancer Research.

SU-E-T-606: Performance of MR-Based 3D FXG Dosimetry for Preclinical Irradiation

Energy Technology Data Exchange (ETDEWEB)

Welch, M [Department of Medical Biophysics, University of Toronto, Toronto, ON (Canada); Jaffray, D [Department of Medical Biophysics, University of Toronto, Toronto, ON (Canada); Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); TECHNA Institute for the Advancement of Technology for Health, Toronto, ON (Canada)

2015-06-15

Purpose: Technological advances have revolutionized preclinical radiation research to enable precise radiation delivery in preclinical models. Kilovoltage x-rays and complex geometries in preclinical radiation studies challenge conventional dosimetry methods. Previously developed gel-based dosimetry provides a viable means of accommodating complex geometries and accurately reporting dose at kV energies. This paper will describe the development and evaluation of gel-based ferrous xylenol-orange (FXG) dosimetry using a 7T preclinical imaging system. Methods: To confirm water equivalence, Zeff values were calculated for the FXG material, water and ICRU defined soft tissue. Proton T1 relaxivity response in FXG was measured using a preclinical 7T MR and a small animal irradiator for a dose range of 1–22 Gy. FXG was contained in 50 ml centrifuge tubes and irradiated with a 225 kVp x-ray beam at a nominal dose rate of 2.3 Gy/min. Pre and post irradiation maps of the T1 relaxivity were collected using variable TR spin-echo imaging (TE 6.65 ms; TR 500, 750, 1000, 1500, 2000, 3000 and 5000 ms) with 2 mm thick slices, 0.325 mm/pixel, 3 averages and an acquisition time of 26 minutes. A linear fit to the change in relaxation rate (1/T1) for the delivered doses reported the gel sensitivity in units of ms{sup -1}Gy{sup -1}. Irradiation and imaging studies were repeated using three batches of gel over 72 hrs. Results: FXG has a Zeff of 3.8 for the 225 kVp spectrum used; differing from water and ICRU defined soft tissue by 0.5% and 2.5%, respectively. The average sensitivity for the FXG dosimeter was 31.5 ± 0.7 ms{sup -1}Gy{sup -1} (R{sup 2} = 0.9957) with a y-intercept of −29.4 ± 9.0 ms{sup -1}. Conclusion: Preliminary results for the FXG dosimeter properties, sensitivity, and dose linearity at preclinical energies is promising. Future work will explore anatomically relevant tissue inclusions to test MR performance. Student funding provided by The Terry Fox Foundation

Pancreatic Enzymes

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... Contact Us DONATE NOW GENERAL DONATION PURPLESTRIDE Pancreatic enzymes Home Facing Pancreatic Cancer Living with Pancreatic Cancer ... and see a registered dietitian. What are pancreatic enzymes? Pancreatic enzymes help break down fats, proteins and ...

Preclinical and clinical investigation of a CCR5 antagonist, AZD5672, in patients with rheumatoid arthritis receiving methotrexate

NARCIS (Netherlands)

Gerlag, Daniëlle M.; Hollis, Sally; Layton, Mark; Vencovský, Jiří; Szekanecz, Zoltán; Braddock, Martin; Tak, Paul P.; Oparanov, Boycho; Stoilov, Rumen; Yaneva, Tanya; Batalov, Anastas; Arteaga, Edgardo Tobias; Escalante, William Otero; Velez, Patricia; Restrepo, Jose Molina; Augustinova, Sevda; Blahova, Anna; Dvorak, Zdenek; Novosad, Libor; Rosa, Jan; Stehlikova, Helena; Vitek, Petr; Balazs, Tibor; Seregely, Katalin; Szombati, Istvan; Tarjan, Katalin; Csengei, Gabor; Galeazzi, Mauro; Saleniece, Sarmite; Saulite-Kandevica, Daina; Coleiro, Bernard; Badurski, Janusz; Brzosko, Marek; Chudzik, Dariusz; Gruszecka-Marczynska, Katarzyna; Hensel, Joanna; Pokrzywnicka-Gajek, Ines; Korpanty-Danda, Joanna; Sochocka-Bykowska, Malgorzata; Tlustochowicz, Witold; Stopinska-Polaszewska, Maria; Gluszko, Piotr; Nedelcovici, Corina; Radulescu, Florin; Gavrila, Mirea; Tanasescu, Coman; Korshunov, Nikolay; Matsievskaia, Galina; Damjanov, Nemanja; Dimic, Aleksandar

2010-01-01

To investigate both the preclinical effects of blocking the chemokine receptor CCR5 and the clinical effects of this approach on the signs and symptoms of rheumatoid arthritis (RA) in patients with active disease. Preclinical evaluations of AZD5672, a small-molecule antagonist of CCR5, were

Standard Operating Procedures (SOPs) for Evaluating the Heart in Preclinical Studies of Duchenne Muscular Dystrophy.

Science.gov (United States)

Duan, Dongsheng; Rafael-Fortney, Jill A; Blain, Alison; Kass, David A; McNally, Elizabeth M; Metzger, Joseph M; Spurney, Christopher F; Kinnett, Kathi

2016-02-01

A recent working group meeting focused on contemporary cardiac issues in Duchenne muscular dystrophy (DMD) was hosted by the National Heart, Lung, and Blood Institute in collaboration with the Parent Project Muscular Dystrophy. An outcome of this meeting was to provide freely available detailed protocols for preclinical animal studies. The goal of these protocols is to improve the quality and reproducibility of cardiac preclinical studies aimed at developing new therapeutics for the prevention and treatment of DMD cardiomyopathy.

Inductance loop and partial

CERN Document Server

Paul, Clayton R

2010-01-01

"Inductance is an unprecedented text, thoroughly discussing "loop" inductance as well as the increasingly important "partial" inductance. These concepts and their proper calculation are crucial in designing modern high-speed digital systems. World-renowned leader in electromagnetics Clayton Paul provides the knowledge and tools necessary to understand and calculate inductance." "With the present and increasing emphasis on high-speed digital systems and high-frequency analog systems, it is imperative that system designers develop an intimate understanding of the concepts and methods in this book. Inductance is a much-needed textbook designed for senior and graduate-level engineering students, as well as a hands-on guide for working engineers and professionals engaged in the design of high-speed digital and high-frequency analog systems."--Jacket.

Nitric oxide is not a negative regulator of metamorphic induction in the abalone Haliotis asinina

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Nobuo eUeda

2014-07-01

Full Text Available Nitric oxide (NO is a second messenger molecule synthesized by the enzyme nitric oxide synthase (NOS that requires the molecular chaperone heat shock protein 90 (HSP90 for normal enzymatic activity. Past studies have revealed that both NO and HSP90 act as negative regulators (repressors of metamorphosis in a diverse range of marine invertebrates, including several molluscan species. Here, we test the role of NO in the metamorphic induction of a vetigastropod mollusc, the tropical abalone Haliotis asinina. Specifically, we 1 test the effects of NO-manipulating pharmacological agents, 2 measure the temporal expression of NOS and HSP90 genes through metamorphosis, and 3 assess the spatial expression of NOS and HSP90 in larvae. We find that inhibition of NOS reduces rates of metamorphosis, indicating that NO facilitates, rather than represses, induction of metamorphosis in H. asinina. The marked increase in NOS expression in putative sensory cells localized to the anterior foot of competent larvae is consistent with NO as an inductive molecule for metamorphosis. In contrast to NOS, HSP90 transcript abundance decreases at competence and there is no evidence of NOS and HSP90 transcript co-localization. This study provides the first evidence of NO as an inductive facilitator of molluscan metamorphosis. Our experimental data suggest that NO modulates signals derived from live inductive substrates via the larval foot to regulate metamorphosis. Inter-specific comparisons of spatial NOS expression in molluscs suggest that the localized pattern of NOS or its protein product is related to the regulatory action of NO in metamorphosis.

Induction of apoptotic cell death by putrescine

DEFF Research Database (Denmark)

Takao, Koichi; Rickhag, Karl Mattias; Hegardt, Cecilia

2006-01-01

that overexpression of a metabolically stable ODC in CHO cells induced a massive cell death unless the cells were grown in the presence of the ODC inhibitor alpha-difluoromethylornithine (DFMO). Cells overexpressing wild-type (unstable) ODC, on the other hand, were not dependent on the presence of DFMO...... for their growth. The induction of cell death was correlated with a dramatic increase in cellular putrescine levels. Analysis using flow cytometry revealed perturbed cell cycle kinetics, with a large accumulation of cells with sub-G1 amounts of DNA, which is a typical sign of apoptosis. Another strong indication...... of apoptosis was the finding that one of the key enzymes in the apoptotic process, caspase-3, was induced when DFMO was omitted from the growth medium. Furthermore, inhibition of the caspase activity significantly reduced the recruitment of cells to the sub-G1 fraction. In conclusion, deregulation of polyamine...

Methodology to assay CYP2E1 mixed function oxidase catalytic activity and its induction

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Arthur I. Cederbaum

2014-01-01

Full Text Available The cytochrome P450 mixed function oxidase enzymes are the major catalysts involved in drug metabolism. There are many forms of P450. CYP2E1 metabolizes many toxicologically important compounds including ethanol and is active in generating reactive oxygen species. Since several of the contributions in the common theme series “Role of CYP2E1 and Oxidative/Nitrosative Stress in the Hepatotoxic Actions of Alcohol” discuss CYP2E1, this methodology review describes assays on how CYP2E1 catalytic activity and its induction by ethanol and other inducers can be measured using substrate probes such as the oxidation of para-nitrophenol to para-nitrocatechol and the oxidation of ethanol to acetaldehyde. Approaches to validate that a particular reaction e.g. oxidation of a drug or toxin is catalyzed by CYP2E1 or that induction of that reaction is due to induction of CYP2E1 are important and specific examples using inhibitors of CYP2E1, anti-CYP2E1 IgG or CYP2E1 knockout and knockin mice will be discussed.

Theory of mind and empathy in preclinical and clinical Huntington's disease.

Science.gov (United States)

Adjeroud, Najia; Besnard, Jérémy; El Massioui, Nicole; Verny, Christophe; Prudean, Adriana; Scherer, Clarisse; Gohier, Bénédicte; Bonneau, Dominique; Allain, Philippe

2016-01-01

We investigated cognitive and affective Theory of Mind (ToM) and empathy in patients with premanifest and manifest Huntington's disease (HD). The relationship between ToM performance and executive skills was also examined. Sixteen preclinical and 23 clinical HD patients, and 39 healthy subjects divided into 2 control groups were given a French adaptation of the Yoni test (Shamay-Tsoory, S.G., Aharon-Peretz, J. (2007). Dissociable prefrontal networks for cognitive and affective theory of mind: a lesion study. Neuropsychologia, 45(3), 3054-67) that examines first- and second-order cognitive and affective ToM processing in separate conditions with a physical control condition. Participants were also given questionnaires of empathy and cognitive tests which mainly assessed executive functions (inhibition and mental flexibility). Clinical HD patients made significantly more errors than their controls in the first- and second-order cognitive and affective ToM conditions of the Yoni task, but exhibited no empathy deficits. However, there was no evidence that ToM impairment was related to cognitive deficits in these patients. Preclinical HD patients were unimpaired in ToM tasks and empathy measures compared with their controls. Our results are consistent with the idea that impaired affective and cognitive mentalizing emerges with the clinical manifestation of HD, but is not necessarily part of the preclinical stage. Furthermore, these impairments appear independent of executive dysfunction and empathy. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

A taxonomy of inductive problems.

Science.gov (United States)

Kemp, Charles; Jern, Alan

2014-02-01

Inductive inferences about objects, features, categories, and relations have been studied for many years, but there are few attempts to chart the range of inductive problems that humans are able to solve. We present a taxonomy of inductive problems that helps to clarify the relationships between familiar inductive problems such as generalization, categorization, and identification, and that introduces new inductive problems for psychological investigation. Our taxonomy is founded on the idea that semantic knowledge is organized into systems of objects, features, categories, and relations, and we attempt to characterize all of the inductive problems that can arise when these systems are partially observed. Recent studies have begun to address some of the new problems in our taxonomy, and future work should aim to develop unified theories of inductive reasoning that explain how people solve all of the problems in the taxonomy.

Half Bridge Inductive Heater

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Zoltán GERMÁN-SALLÓ

2015-12-01

Full Text Available Induction heating performs contactless, efficient and fast heating of conductive materials, therefore became one of the preferred heating procedure in industrial, domestic and medical applications. During induction heating the high-frequency alternating currents that heat the material are induced by means of electromagnetic induction. The material to be heated is placed inside the time-varying magnetic field generated by applying a highfrequency alternating current to an induction coil. The alternating electromagnetic field induces eddy currents in the workpiece, resulting resistive losses, which then heat the material. This paper describes the design of a power electronic converter circuit for induction heating equipment and presents the obtained results. The realized circuit is a low power half bridge resonant inverter which uses power MOS transistors and adequate driver circuits.

Mathematical modeling of enzyme production using Trichoderma harzianum P49P11 and sugarcane bagasse as carbon source.

Science.gov (United States)

Gelain, Lucas; da Cruz Pradella, José Geraldo; da Costa, Aline Carvalho

2015-12-01

A mathematical model to describe the kinetics of enzyme production by the filamentous fungus Trichoderma harzianum P49P11 was developed using a low cost substrate as main carbon source (pretreated sugarcane bagasse). The model describes the cell growth, variation of substrate concentration and production of three kinds of enzymes (cellulases, beta-glucosidase and xylanase) in different sugarcane bagasse concentrations (5; 10; 20; 30; 40 gL(-1)). The 10 gL(-1) concentration was used to validate the model and the other to parameter estimation. The model for enzyme production has terms implicitly representing induction and repression. Substrate variation was represented by a simple degradation rate. The models seem to represent well the kinetics with a good fit for the majority of the assays. Validation results indicate that the models are adequate to represent the kinetics for a biotechnological process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Inductive Reasoning and Writing

Science.gov (United States)

Rooks, Clay; Boyd, Robert

2003-01-01

Induction, properly understood, is not merely a game, nor is it a gimmick, nor is it an artificial way of explaining an element of reasoning. Proper understanding of inductive reasoning--and the various types of reasoning that the authors term inductive--enables the student to evaluate critically other people's writing and enhances the composition…

Effect of Sodium Fluoride Ingestion on Malondialdehyde Concentration and the Activity of Antioxidant Enzymes in Rat Erythrocytes

Directory of Open Access Journals (Sweden)

José A. Morales-González

2010-06-01

Full Text Available Fluoride intoxication has been shown to produce diverse deleterious metabolic alterations within the cell. To determine the effects of sodium fluoride (NaF treatment on malondialdehyde (MDA levels and on the activity of antioxidant enzymes in rat erythrocytes, Male Wistar rats were treated with 50 ppm of NaF or were untreated as controls. Erythrocytes were obtained from rats sacrificed weekly for up to eight weeks and the concentration of MDA in erythrocyte membrane was determined. In addition, the activity of the enzymes superoxide, dismutase, catalase, and glutathione peroxidase were determined. Treatment with NaF produces an increase in the concentration of malondialdehyde in the erythrocyte membrane only after the eight weeks of treatment. On the other hand, antioxidant enzyme activity was observed to increase after the fourth week of NaF treatment. In conclusion, intake of NaF produces alterations in the erythrocyte of the male rat, which indicates induction of oxidative stress.

Measuring the Enzyme Activity of Arabidopsis Deubiquitylating Enzymes.

Science.gov (United States)

Kalinowska, Kamila; Nagel, Marie-Kristin; Isono, Erika

2016-01-01

Deubiquitylating enzymes, or DUBs, are important regulators of ubiquitin homeostasis and substrate stability, though the molecular mechanisms of most of the DUBs in plants are not yet understood. As different ubiquitin chain types are implicated in different biological pathways, it is important to analyze the enzyme characteristic for studying a DUB. Quantitative analysis of DUB activity is also important to determine enzyme kinetics and the influence of DUB binding proteins on the enzyme activity. Here, we show methods to analyze DUB activity using immunodetection, Coomassie Brilliant Blue staining, and fluorescence measurement that can be useful for understanding the basic characteristic of DUBs.

A review of targeted therapies evaluated by the Pediatric Preclinical Testing Program for osteosarcoma

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Valerie eSampson

2013-05-01

Full Text Available Osteosarcoma, the most common malignant bone tumor of childhood, is a high grade primary bone sarcoma that occurs mostly in adolescence. Standard treatment consists of surgery in combination with multi-agent chemotherapy regimens. The development and approval of imatinib for Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL in children and the fully human monoclonal antibody, anti-GD2, as part of an immune therapy for high-risk neuroblastoma patients have established the precedent for use of targeted inhibitors along with standard chemotherapy backbones. However, few targeted agents tested have achieved traditional clinical end points for osteosarcoma. Many biological agents demonstrating anti-tumor responses in preclinical and early phase clinical testing have failed to reach response thresholds to justify randomized trials with large numbers of patients. The development of targeted therapies for pediatric cancer remains a significant challenge. To aid in the prioritization of new agents for clinical testing, the Pediatric Preclinical Testing Program (PPTP has developed reliable and robust preclinical pediatric cancer models to rapidly screen agents for activity in multiple childhood cancers and establish pharmacological parameters and effective drug concentrations for clinical trials. In this article, we examine a range of standard and novel agents that have been evaluated by the PPTP, and we discuss the preclinical and clinical development of these for the treatment of osteosarcoma. We further demonstrate that committed resources for hypothesis-driven drug discovery and development are needed to yield clinical successes in the search for new therapies for this pediatric disease.

The composition of accessory enzymes of Penicillium chrysogenum P33 revealed by secretome and synergistic effects with commercial cellulase on lignocellulose hydrolysis.

Science.gov (United States)

Yang, Yi; Yang, Jinshui; Liu, Jiawen; Wang, Ruonan; Liu, Liang; Wang, Fengqin; Yuan, Hongli

2018-06-01

Herein, we report the secretome of Penicillium chrysogenum P33 under induction of lignocellulose for the first time. A total of 356 proteins were identified, including complete cellulases and numerous hemicellulases. Supplementing a commercial cellulase with increasing dosage of P33 enzyme cocktail from 1 to 5 mg/g substrate increased the release of reducing sugars from delignified corn stover by 21.4% to 106.8%. When 50% cellulase was replaced by P33 enzyme cocktail, release of reducing sugars was 78.6% higher than with cellulase alone. Meanwhile, glucan and xylan conversion was increased by 37% and 106%, respectively. P33 enzyme cocktail also enhanced commercial cellulase hydrolysis against four different delignified lignocellulosic biomass. These findings demonstrate that mixing appropriate amount of P33 cocktail with cellulase improves polysaccharide hydrolysis, suggesting P33 enzymes have great potential for industrial applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

Threats to validity in the design and conduct of preclinical efficacy studies: a systematic review of guidelines for in vivo animal experiments.

Directory of Open Access Journals (Sweden)

Valerie C Henderson

Full Text Available 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.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.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.

Threats to validity in the design and conduct of preclinical efficacy studies: a systematic review of guidelines for in vivo animal experiments.

Science.gov (United States)

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

2013-01-01

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. 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. 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.

Arginase induction and activation during ischemia and reperfusion and functional consequences for the heart

Directory of Open Access Journals (Sweden)

Klaus-Dieter eSchlüter

2015-03-01

Full Text Available Induction and activation of arginase is among the fastest responses of the heart to ischemic events. Induction of arginase expression and enzyme activation under ischemic conditions shifts arginine consumption from nitric oxide formation (NO to the formation of ornithine and urea. In the heart such a switch in substrate utilisation reduces the impact of the NO/cGMP-pathway on cardiac function that requires intact electromechanical coupling but at the same time it induces ornithine-dependent pathways such as the polyamine metabolism. Both effects significantly reduce the recovery of heart function during reperfusion and thereby limits the success of reperfusion strategies. In this context, changes in arginine consumption trigger cardiac remodelling in an unfavourable way and increases the risk of arrhythmia, specifically in the initial post-ischemic period in which arginase activity is dominating. However, during the entire ischemic period arginase activation might be a meaningful adaptation that is specifically relevant for reperfusion following prolonged ischemic periods. Therefore, a precise understanding about the underlying mechanism that leads to arginase induction as well as of it’s mechanistic impact on post-ischemic hearts is required for optimizing reperfusion strategies. In this review we will summarize our current understanding of these processes and give an outlook about possible treatment options for the future.

Neuroprotection in Parkinson's disease: A systematic review of the preclinical data

NARCIS (Netherlands)

Douna, H.; Bavelaar, B.M.; Pellikaan, H.; Olivier, B.; Pieters, T.

2012-01-01

Aim: This study aimed to systematically review the preclinical data of neuroprotective agents for Parkinson's disease (PD) to support the translation of these compounds. Methods: The study consisted of two phases. In phase I, Pubmed and Scopus were systematically searched for neuroprotective agents

Nanomaterials with enzyme-like characteristics (nanozymes): next-generation artificial enzymes.

Science.gov (United States)

Wei, Hui; Wang, Erkang

2013-07-21

Over the past few decades, researchers have established artificial enzymes as highly stable and low-cost alternatives to natural enzymes in a wide range of applications. A variety of materials including cyclodextrins, metal complexes, porphyrins, polymers, dendrimers and biomolecules have been extensively explored to mimic the structures and functions of naturally occurring enzymes. Recently, some nanomaterials have been found to exhibit unexpected enzyme-like activities, and great advances have been made in this area due to the tremendous progress in nano-research and the unique characteristics of nanomaterials. To highlight the progress in the field of nanomaterial-based artificial enzymes (nanozymes), this review discusses various nanomaterials that have been explored to mimic different kinds of enzymes. We cover their kinetics, mechanisms and applications in numerous fields, from biosensing and immunoassays, to stem cell growth and pollutant removal. We also summarize several approaches to tune the activities of nanozymes. Finally, we make comparisons between nanozymes and other catalytic materials (other artificial enzymes, natural enzymes, organic catalysts and nanomaterial-based catalysts) and address the current challenges and future directions (302 references).

In vitro induction of O6-methylguanine-DNA methyltransferase in C3H/10T1/2 cells by X-rays is inhibited by nitrogen

International Nuclear Information System (INIS)

Hofe, E. von; Kennedy, A.R.

1988-01-01

Ionizing radiation is one of the most potent inducers of O 6 -methylguanine-DNA methyltransferase (MT) in rat liver in vivo. In this study we show that MT is readily induced in C3H/10T1/2 cells in culture, which provides a system more amenable to determining the molecular events involved in the induction of this repair enzyme. Maximal induction was observed in logarithmically growing cells 48 h after a dose of 200 rad, similar to the optimal induction time seen in rat liver in vivo. The absolute level of MT observed in C3H/10T1/2 cells which had been at confluence for 24 h was less than in cells in log growth but was still inducible by X-rays, exhibiting an ∼ 2-fold increase over unirradiated cells similar to MT induction in logarithmically growing cells. Irradiating cells under anaerobic conditions abolished MT induction by 100 rad. Cells irradiated with 200 rad under anaerobic conditions exhibited ∼ 70% inhibition of induction compared with aerobically irradiated cells. The possibility that MT may be partially inactivated by interaction with radicals produced by ionizing radiation is discussed. (author)

Role of SimMan in teaching clinical skills to preclinical medical students

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Swamy Meenakshi

2013-02-01

Full Text Available Abstract Background Simulation training has potential in developing clinical skills in pre-clinical medical students, but there is little evidence on its effectiveness. Methods Twenty four first year graduate entry preclinical medical students participated in this crossover study. They were divided into two groups, one performed chest examination on each other and the other used SimMan. The groups then crossed over. A pretest, midtest and post-test was conducted in which the students answered the same questionnaire with ten questions on knowledge, and confidence levels rated using a 5 point Likert scale. They were assessed formatively using the OSCE marking scheme. At the end of the session, 23 students completed a feedback questionnaire. Data was analyzed using one-way ANOVA and independent t-test. Results When the two groups were compared, there was no significant difference in the pretest and the post-test scores on knowledge questions whereas the midtest scores increased significantly (P Mean confidence ratings increased from the pretest to midtest and then further in the post-test for both groups. Their confidence ratings increased significantly in differentiating between normal and abnormal signs [Group starting with SimMan, between pretest and midtest (P= 0.01 and group starting with peer examination, between midtest and post-test (P=0.02]. When the students’ ability to perform examination on each other for both groups was compared, there was a significant increase in the scores of the group starting with SimMan (P=0.007. Conclusions This pilot study demonstrated a significant improvement in the students’ knowledge and competence to perform chest examination after simulation with an increase in the student’s perceived levels of confidence. Feedback from the students was extremely positive. SimMan acts as a useful adjunct to teach clinical skills to preclinical medical students by providing a simulated safe environment and thus aids

Induction of a Torpor-Like State by 5’-AMP Does Not Depend on H2S Production

Science.gov (United States)

Dugbartey, George J.; Bouma, Hjalmar R.; Strijkstra, Arjen M.; Boerema, Ate S.; Henning, Robert H.

2015-01-01

Background Therapeutic hypothermia is used to reduce ischemia/reperfusion injury (IRI) during organ transplantation and major surgery, but does not fully prevent organ injury. Interestingly, hibernating animals undergo repetitive periods of low body temperature called ‘torpor’ without signs of organ injury. Recently, we identified an essential role of hydrogen sulfide (H2S) in entrance into torpor and preservation of kidney integrity during hibernation. A torpor-like state can be induced pharmacologically by injecting 5’-Adenosine monophosphate (5’-AMP). The mechanism by which 5’-AMP leads to the induction of a torpor-like state, and the role of H2S herein, remains to be unraveled. Therefore, we investigated whether induction of a torpor-like state by 5-AMP depends on H2S production. Methods To study the role of H2S on the induction of torpor, amino-oxyacetic acid (AOAA), a non-specific inhibitor of H2S, was administered before injection with 5'-AMP to block endogenous H2S production in Syrian hamster. To assess the role of H2S on maintenance of torpor induced by 5’-AMP, additional animals were injected with AOAA during torpor. Key Results During the torpor-like state induced by 5’-AMP, the expression of H2S- synthesizing enzymes in the kidneys and plasma levels of H2S were increased. Blockade of these enzymes inhibited the rise in the plasma level of H2S, but neither precluded torpor nor induced arousal. Remarkably, blockade of endogenous H2S production was associated with increased renal injury. Conclusions Induction of a torpor-like state by 5’-AMP does not depend on H2S, although production of H2S seems to attenuate renal injury. Unraveling the mechanisms by which 5’-AMP reduces the metabolism without organ injury may allow optimization of current strategies to limit (hypothermic) IRI and improve outcome following organ transplantation, major cardiac and brain surgery. PMID:26295351

Treatment of TBI with Hormonal and Pharmacological Support, Preclinical Validation Using Diffuse and Mechanical TBI Animal Models

Science.gov (United States)

2016-05-01

Award Number: PT075653 (grant) W81XWH-08-2-0153 (contract) TITLE: Treatment of TBI with Hormonal and Pharmacological Support, Preclinical...TITLE AND SUBTITLE 5a. CONTRACT NUMBER W81XWH-08-2-0153 Treatment of TBI with Hormonal and Pharmacological Support, Preclinical Validation Using...rats. Our in vivo tests also included MRI imaging, focusing on edema resolution and reduction of diffuse axonal damage (fractional anisotropy

[Advances on enzymes and enzyme inhibitors research based on microfluidic devices].

Science.gov (United States)

Hou, Feng-Hua; Ye, Jian-Qing; Chen, Zuan-Guang; Cheng, Zhi-Yi

2010-06-01

With the continuous development in microfluidic fabrication technology, microfluidic analysis has evolved from a concept to one of research frontiers in last twenty years. The research of enzymes and enzyme inhibitors based on microfluidic devices has also made great progress. Microfluidic technology improved greatly the analytical performance of the research of enzymes and enzyme inhibitors by reducing the consumption of reagents, decreasing the analysis time, and developing automation. This review focuses on the development and classification of enzymes and enzyme inhibitors research based on microfluidic devices.

Direct comparison of enzyme histochemical and immunohistochemical methods to localize an enzyme

NARCIS (Netherlands)

van Noorden, Cornelis J. F.

2002-01-01

Immunohistochemical localization of enzymes is compared directly with localization of enzyme activity with (catalytic) enzyme histochemical methods. The two approaches demonstrate principally different aspects of an enzyme. The immunohistochemical method localizes the enzyme protein whether it is

Plant Growth-Promoting Rhizobacteria Enhance Salinity Stress Tolerance in Okra through ROS-Scavenging Enzymes

Directory of Open Access Journals (Sweden)

Sheikh Hasna Habib

2016-01-01

Full Text Available Salinity is a major environmental stress that limits crop production worldwide. In this study, we characterized plant growth-promoting rhizobacteria (PGPR containing 1-aminocyclopropane-1-carboxylate (ACC deaminase and examined their effect on salinity stress tolerance in okra through the induction of ROS-scavenging enzyme activity. PGPR inoculated okra plants exhibited higher germination percentage, growth parameters, and chlorophyll content than control plants. Increased antioxidant enzyme activities (SOD, APX, and CAT and upregulation of ROS pathway genes (CAT, APX, GR, and DHAR were observed in PGPR inoculated okra plants under salinity stress. With some exceptions, inoculation with Enterobacter sp. UPMR18 had a significant influence on all tested parameters under salt stress, as compared to other treatments. Thus, the ACC deaminase-containing PGPR isolate Enterobacter sp. UPMR18 could be an effective bioresource for enhancing salt tolerance and growth of okra plants under salinity stress.

Induction melter apparatus

Science.gov (United States)

Roach, Jay A [Idaho Falls, ID; Richardson, John G [Idaho Falls, ID; Raivo, Brian D [Idaho Falls, ID; Soelberg, Nicholas R [Idaho Falls, ID

2008-06-17

Apparatus and methods of operation are provided for a cold-crucible-induction melter for vitrifying waste wherein a single induction power supply may be used to effect a selected thermal distribution by independently energizing at least two inductors. Also, a bottom drain assembly may be heated by an inductor and may include an electrically resistive heater. The bottom drain assembly may be cooled to solidify molten material passing therethrough to prevent discharge of molten material therefrom. Configurations are provided wherein the induction flux skin depth substantially corresponds with the central longitudinal axis of the crucible. Further, the drain tube may be positioned within the induction flux skin depth in relation to material within the crucible or may be substantially aligned with a direction of flow of molten material within the crucible. An improved head design including four shells forming thermal radiation shields and at least two gas-cooled plenums is also disclosed.

Deep Machine Learning Application to the Detection of Preclinical Neurodegenerative Diseases of Aging

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Mathew J. Summers

2017-12-01

Full Text Available Artificial intelligence (AI deep learning protocols offer solutions to complex data processing and analysis. Increasingly these solutions are being applied in the healthcare field, most commonly in processing complex medical imaging data used for diagnosis. Current models apply AI to screening populations of patients for markers of disease and report detection accuracy rates exceeding those of human data screening. In this paper, we explore an alternate model for AI deployment, that of monitoring and analysing an individual’s level of function over time. In adopting this approach, we propose that AI may provide highly accurate and reliable detection of preclinical disease states associated with aging-related neurodegenerative diseases. One of the key challenges facing clinical detection of preclinical phases of diseases such as dementia is the high degree of inter-individual variability in aging-related changes to cognitive function. AI based monitoring of an individual over time offers the potential for the early detection of change in function for the individual, rather than relying on comparing the individual’s performance to population norms. We explore an approach to developing AI platforms for individual monitoring and preclinical disease detection and examine the potential benefits to the stakeholders in this technological development.

Atomoxetine for hoarding disorder: A pre-clinical and clinical investigation.

Science.gov (United States)

Grassi, Giacomo; Micheli, Laura; Di Cesare Mannelli, Lorenzo; Compagno, Elisa; Righi, Lorenzo; Ghelardini, Carla; Pallanti, Stefano

2016-12-01

Despite several studies suggested that inattention and impulsivity-compulsivity could represent two core dimensions of hoarding disorder (HD), only a small case series study investigated the effectiveness of attention-deficit-hyperactivity-disorder (ADHD) medications in HD. The aim of the present study was to target attentional and inhibitory control networks in HD patients through the ADHD medication atomoxetine, moving from a preclinical investigation on an animal model of compulsive-like behavior (marble burying test) to a clinical investigation on both medicated and unmedicated patients with a primary diagnosis of HD without ADHD. Our preclinical investigation showed that acute administration of atomoxetine significantly reduced the compulsive-like behaviours of mice in the marble burying test without affecting neither locomotor activity and coordination nor exploration behaviours. When compared, atomoxetine and fluoxetine showed similar effects on the marble burying test. However, fluoxetine impaired both locomotor and exploratory activity. In our clinical investigation 12 patients were enrolled and 11 patients completed an open trial with atomoxetine at flexible dose (40-80 mg) for 12 weeks. At the endpoint the mean UCLA Hoarding Severity Scale score decreased by 41.3% for the whole group (p = 0003). Six patients were classified as full responders (mean symptom reduction of 57.2%) and three patients as partial responders (mean symptom reduction of 27.3%). Inattentive and impulsivity symptoms showed a significant mean score reduction of 18.5% from baseline to the endpoint (F (1,9) = 20.9, p = 0.0013). Hoarding symptoms improvement was correlated to reduction of patients' disability and increased in their global functioning. These preclinical and clinical data suggest that atomoxetine may be effective for HD and therefore should be considered for future controlled trials. Copyright © 2016 Elsevier Ltd. All rights reserved.

Computational enzyme design: transitioning from catalytic proteins to enzymes.

Science.gov (United States)

Mak, Wai Shun; Siegel, Justin B

2014-08-01

The widespread interest in enzymes stem from their ability to catalyze chemical reactions under mild and ecologically friendly conditions with unparalleled catalytic proficiencies. While thousands of naturally occurring enzymes have been identified and characterized, there are still numerous important applications for which there are no biological catalysts capable of performing the desired chemical transformation. In order to engineer enzymes for which there is no natural starting point, efforts using a combination of quantum chemistry and force-field based protein molecular modeling have led to the design of novel proteins capable of catalyzing chemical reactions not catalyzed by naturally occurring enzymes. Here we discuss the current status and potential avenues to pursue as the field of computational enzyme design moves forward. Published by Elsevier Ltd.

Postnatal modulation of hepatic biotransformation system enzymes via translactational exposure of F1 mouse pups to turmeric and curcumin.

Science.gov (United States)

Singh, A; Singh, S P; Bamezai, R

1995-09-04

The potential for the transfer of active principle(s) of turmeric (Curcuma longa L.) and curcumin (major pigment in turmeric) via translactational route and its modulatory influence on the hepatic biotransformation system enzymes in the lactating dams and their suckling offspring was assessed. Turmeric (4 g/kg b.w. per day) and curcumin (0.4 g/kg b.w. per day) induced significant (P curcumin (0.2 g/kg b.w. per day) could modulate hepatic GST activity (P curcumin (0.4 g/kg b.w.). The induction in hepatic biotransformation system enzymes in lactating dams and F1 progeny suggests the passage of active constituents and/or metabolites of turmeric and curcumin via the translactational route.

Preclinical models of shock and sepsis: what can they tell us?

NARCIS (Netherlands)

Marshall, John C.; Deitch, Edwin; Moldawer, Lyle L.; Opal, Steven; Redl, Heinz; van der Poll, Tom

2005-01-01

The goal of translational research is to transform biologic knowledge into new treatments for human disease. Although preclinical models replicate some of the features of the disease process modeled, they invariably fail to reproduce the complexity of human illness, and by their very experimental

Pre-clinical functional magnetic resonance imaging. Pt. I. The kidney

Energy Technology Data Exchange (ETDEWEB)

Zoellner, Frank G.; Kalayciyan, Raffi; Chacon-Caldera, Jorge; Zimmer, Fabian; Schad, Lothar R. [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine

2014-07-01

The prevalence of chronic kidney disease (CKD) is increasing worldwide. In Europe alone, at least 8% of the population currently has some degree of CKD. CKD is associated with serious comorbidity, reduced life expectancy, and high economic costs; hence, the early detection and adequate treatment of kidney disease is important. Pre-clinical research can not only give insights into the mechanisms of the various kidney diseases but it also allows for investigating the outcome of new drugs developed to treat kidney disease. Functional magnetic resonance imaging provides non-invasive access to tissue and organ function in animal models. Advantages over classical animal research approaches are numerous: the same animal might be repeatedly imaged to investigate a progress or a treatment of disease over time. This has also a direct impact on animal welfare and the refinement of classical animal experiments as the number of animals in the studies might be reduced. In this paper, we review current state of the art in functional magnetic resonance imaging with a focus on pre-clinical kidney imaging.

Pre-clinical functional magnetic resonance imaging. Pt. I. The kidney

International Nuclear Information System (INIS)

Zoellner, Frank G.; Kalayciyan, Raffi; Chacon-Caldera, Jorge; Zimmer, Fabian; Schad, Lothar R.

2014-01-01

The prevalence of chronic kidney disease (CKD) is increasing worldwide. In Europe alone, at least 8% of the population currently has some degree of CKD. CKD is associated with serious comorbidity, reduced life expectancy, and high economic costs; hence, the early detection and adequate treatment of kidney disease is important. Pre-clinical research can not only give insights into the mechanisms of the various kidney diseases but it also allows for investigating the outcome of new drugs developed to treat kidney disease. Functional magnetic resonance imaging provides non-invasive access to tissue and organ function in animal models. Advantages over classical animal research approaches are numerous: the same animal might be repeatedly imaged to investigate a progress or a treatment of disease over time. This has also a direct impact on animal welfare and the refinement of classical animal experiments as the number of animals in the studies might be reduced. In this paper, we review current state of the art in functional magnetic resonance imaging with a focus on pre-clinical kidney imaging.

Spinal Cord Stimulation for Treating Chronic Pain: Reviewing Preclinical and Clinical Data on Paresthesia-Free High-Frequency Therapy.

Science.gov (United States)

Chakravarthy, Krishnan; Richter, Hira; Christo, Paul J; Williams, Kayode; Guan, Yun

2018-01-01

Traditional spinal cord stimulation (SCS) requires that paresthesia overlaps chronic painful areas. However, the new paradigm high-frequency SCS (HF-SCS) does not rely on paresthesia. A review of preclinical and clinical studies regarding the use of paresthesia-free HF-SCS for various chronic pain states. We reviewed available literatures on HF-SCS, including Nevro's paresthesia-free ultra high-frequency 10 kHz therapy (HF10-SCS). Data sources included relevant literature identified through searches of PubMed, MEDLINE/OVID, and SCOPUS, and manual searches of the bibliographies of known primary and review articles. The primary goal is to describe the present developing conceptions of preclinical mechanisms of HF-SCS and to review clinical efficacy on paresthesia-free HF10-SCS for various chronic pain states. HF10-SCS offers a novel pain reduction tool without paresthesia for failed back surgery syndrome and chronic axial back pain. Preclinical findings indicate that potential mechanisms of action for paresthesia-free HF-SCS differ from those of traditional SCS. To fully understand and utilize paresthesia-free HF-SCS, mechanistic study and translational research will be very important, with increasing collaboration between basic science and clinical communities to design better trials and optimize the therapy based on mechanistic findings from effective preclinical models and approaches. Future research in these vital areas may include preclinical and clinical components conducted in parallel to optimize the potential of this technology. © 2017 International Neuromodulation Society.

Practicing induction:

DEFF Research Database (Denmark)

Sprogøe, Jonas; Rohde, Nicolas

2009-01-01

We claim that induction potentially triggers both individual and organizational learning and by drawing on practice-based theory we discuss how the interplay between individual and organization, what we call a generative dance, ignites both kinds of learning.......We claim that induction potentially triggers both individual and organizational learning and by drawing on practice-based theory we discuss how the interplay between individual and organization, what we call a generative dance, ignites both kinds of learning....

Endoglucanase enzyme protein engineering by site-directed mutagenesis to improve the enzymatic properties and its expression in yeast

Directory of Open Access Journals (Sweden)

Farnaz Nikzad Jamnani

2013-11-01

Full Text Available Introduction: Fossil fuel is an expensive and finite energy source. Therefore, the use of renewable energy and biofuels production has been taken into consideration. One of the most suitable raw materials for biofuels is cellulosic compounds. Only microorganisms that contain cellulose enzymes can decompose cellulose and fungus of Trichodermareesei is the most important producer of this enzyme. Methods: In this study the nucleotide sequence of endoglucanase II, which is the starter of attack to cellulose chains, synthesized from amino acid sequence of this enzyme in fungus T.reesei and based on codon usage in the host; yeast Pichiapastoris. To produce optimized enzyme and to decrease the production time and enzyme price, protein engineering will be used. There are some methods to improve the enzymatic properties like site-directed mutagenesis in which amino-acid replacement occur. In this study two mutations were induced in endoglucanase enzyme gene by PCR in which free syctein positions 169 and 393 were switched to valine and histidine respectively. Then this gene was inserted into the pPinka expression vector and cloned in Escherichia coli. The recombinant plasmids were transferred into P.pastoris competent cells with electroporation, recombinant yeasts were cultured in BMMY medium and induced with methanol. Results: The sequencing of gene proved the induction of the two mutations and the presence of recombinant enzyme was confirmed by dinitrosalicilic acid method and SDS-PAGE. Conclusion: Examination of biochemical properties revealed that the two mutations simultaneously decreased catalytic power, thermal stability and increased the affinity of enzyme and substrate.

Pharmacokinetic modeling of an induction regimen for in vivo combined testing of novel drugs against pediatric acute lymphoblastic leukemia xenografts.

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Barbara Szymanska

Full Text Available Current regimens for induction therapy of pediatric acute lymphoblastic leukemia (ALL, or for re-induction post relapse, use a combination of vincristine (VCR, a glucocorticoid, and L-asparaginase (ASP with or without an anthracycline. With cure rates now approximately 80%, robust pre-clinical models are necessary to prioritize active new drugs for clinical trials in relapsed/refractory patients, and the ability of these models to predict synergy/antagonism with established therapy is an essential attribute. In this study, we report optimization of an induction-type regimen by combining VCR, dexamethasone (DEX and ASP (VXL against ALL xenograft models established from patient biopsies in immune-deficient mice. We demonstrate that the VXL combination was synergistic in vitro against leukemia cell lines as well as in vivo against ALL xenografts. In vivo, VXL treatment caused delays in progression of individual xenografts ranging from 22 to >146 days. The median progression delay of xenografts derived from long-term surviving patients was 2-fold greater than that of xenografts derived from patients who died of their disease. Pharmacokinetic analysis revealed that systemic DEX exposure in mice increased 2-fold when administered in combination with VCR and ASP, consistent with clinical findings, which may contribute to the observed synergy between the 3 drugs. Finally, as proof-of-principle we tested the in vivo efficacy of combining VXL with either the Bcl-2/Bcl-xL/Bcl-w inhibitor, ABT-737, or arsenic trioxide to provide evidence of a robust in vivo platform to prioritize new drugs for clinical trials in children with relapsed/refractory ALL.

Intracellular β-Glucosidases CEL1a and CEL1b Are Essential for Cellulase Induction on Lactose in Trichoderma reesei

Science.gov (United States)

Xu, Jintao; Zhao, Guolei; Kou, Yanbo; Zhang, Weixin; Zhou, Qingxin; Chen, Guanjun

2014-01-01

Lactose (1,4-O-β-d-galacto-pyranosyl-d-glucose) induces cellulolytic enzymes in Trichoderma reesei and is in fact one of the most important soluble carbon sources used to produce cellulases on an industrial level. The mechanism underlying the induction is, however, not fully understood. In this study, we investigated the cellular functions of the intracellular β-glucosidases CEL1a and CEL1b in the induction of cellulase genes by lactose in T. reesei. We demonstrated that while CEL1a and CEL1b were functionally equivalent in mediating the induction, the simultaneous absence of these intracellular β-glucosidases abolished cbh1 gene expression on lactose. d-Galactose restored the efficient cellulase gene induction in the Δcel1a strain independently of its reductive metabolism, but not in the Δcel1a Δcel1b strain. A further comparison of the transcriptional responses of the Δcel1a Δcel1b strain complemented with wild-type CEL1a or a catalytically inactive CEL1a version and the Δcel1a strain constitutively expressing CEL1a or the Kluyveromyces lactis β-galactosidase LAC4 showed that both the CEL1a protein and its glycoside hydrolytic activity were indispensable for cellulase induction by lactose. We also present evidence that intracellular β-glucosidase-mediated lactose induction is further conveyed to XYR1 to ensure the efficiently induced expression of cellulase genes. PMID:24879125

Enhanced thyroid hormone breakdown in hepatocytes by mutual induction of the constitutive androstane receptor (CAR, NR1I3) and arylhydrocarbon receptor by benzo[a]pyrene and phenobarbital

International Nuclear Information System (INIS)

Schraplau, Anne; Schewe, Bettina; Neuschäfer-Rube, Frank; Ringel, Sebastian; Neuber, Corinna; Kleuser, Burkhard; Püschel, Gerhard P.

2015-01-01

Xenobiotics may interfere with the hypothalamic-pituitary-thyroid endocrine axis by inducing enzymes that inactivate thyroid hormones and thereby reduce the metabolic rate. This induction results from an activation of xeno-sensing nuclear receptors. The current study shows that benzo[a]pyrene, a frequent contaminant of processed food and activator of the arylhydrocarbon receptor (AhR) activated the promoter and induced the transcription of the nuclear receptor constitutive androstane receptor (CAR, NR1I3) in rat hepatocytes. Likewise, phenobarbital induced the AhR transcription. This mutual induction of the nuclear receptors enhanced the phenobarbital-dependent induction of the prototypic CAR target gene Cyp2b1 as well as the AhR-dependent induction of UDP-glucuronosyltransferases. In both cases, the induction by the combination of both xenobiotics was more than the sum of the induction by either substance alone. By inducing the AhR, phenobarbital enhanced the benzo[a]pyrene-dependent reduction of thyroid hormone half-life and the benzo[a]pyrene-dependent increase in the rate of thyroid hormone glucuronide formation in hepatocyte cultures. CAR ligands might thus augment the endocrine disrupting potential of AhR activators by an induction of the AhR

Pre-Clinical Testing of Real-Time PCR Assays for Diarrheal Disease Agents of Genera Escherichia and Shigella

Science.gov (United States)

2014-05-16

FOR DIARRHEAL DISEASE AGENTS OF GENERA ESCHERICHIA AND SHIGELLA May 16, 2014 Reporting Period: October 1, 2010 to September 30, 2013...10-2010 - 30-09-2013 PRE-CLINICAL TESTING OF REAL-TIME PCR ASSAYS FOR DIARRHEAL DISEASE AGENTS OF GENERA ESCHERICHIA AND SHIGELLA ...Texas (MOA 2007 - 2013. Agreement No.: DODI 4000.19; AFI 25-201). Pre-clinical test results qualify ETEC and Shigella real-time PCR assays as lead

Appropriate experimental approaches for predicting abuse potential and addictive qualities in preclinical drug discovery.

Science.gov (United States)

Mead, Andy N

2014-11-01

Drug abuse is an increasing social and public health issue, putting the onus on drug developers and regulatory agencies to ensure that the abuse potential of novel drugs is adequately assessed prior to product launch. This review summarizes the core preclinical data that frequently contribute to building an understanding of abuse potential for a new molecular entity, in addition to highlighting models that can provide increased resolution regarding the level of risk. Second, an important distinction between abuse potential and addiction potential is drawn, with comments on how preclinical models can inform on each. While the currently adopted preclinical models possess strong predictive validity, there are areas for future refinement and research. These areas include a more refined use of self-administration models to assess relative reinforcement; and the need for open innovation in pursuing improvements. There is also the need for careful scientifically driven application of models rather than a standardization of methodologies, and the need to explore the opportunities that may exist for enhancing the value of physical dependence and withdrawal studies by focusing on withdrawal-induced drug seeking, rather than broad symptomology.

Promoting evidence based medicine in preclinical medical students via a federated literature search tool.

Science.gov (United States)

Keim, Samuel Mark; Howse, David; Bracke, Paul; Mendoza, Kathryn

2008-01-01

Medical educators are increasingly faced with directives to teach Evidence Based Medicine (EBM) skills. Because of its nature, integrating fundamental EBM educational content is a challenge in the preclinical years. To analyse preclinical medical student user satisfaction and feedback regarding a clinical EBM search strategy. The authors introduced a custom EBM search option with a self-contained education structure to first-year medical students. The implementation took advantage of a major curricular change towards case-based instruction. Medical student views and experiences were studied regarding the tool's convenience, problems and the degree to which they used it to answer questions raised by case-based instruction. Surveys were completed by 70% of the available first-year students. Student satisfaction and experiences were strongly positive towards the EBM strategy, especially of the tool's convenience and utility for answering issues raised during case-based learning sessions. About 90% of the students responded that the tool was easy to use, productive and accessed for half or more of their search needs. This study provides evidence that the integration of an educational EBM search tool can be positively received by preclinical medical students.

The nature of outsourced preclinical research--the example of chemical synthesis.

Science.gov (United States)

Festel, Gunter W

2013-09-01

The possibility to buy standardized external services or even new and innovative methods within drug discovery has increased dramatically during the last decades. Service providers are able to provide timely and efficient solutions to any given problem within preclinical research. The outsourcing behavior depends on the specific company type. Generally, the outsourcing level of emerging pharmaceutical and biotechnology companies is much higher than established companies due to low or missing internal resources. Whereas the "make-or-buy" decisions of large and fully integrated pharmaceutical companies are mainly competency driven, those of mid-size and small pharmaceutical, as well as biotech companies show a specific combination of cost/capacity and competency. The three different cooperation models "price competition", "project selection," and "strategic partnership" were identified. For all types of companies, the cooperation model of "strategic partnership" offers access to high-level expertise while reducing fixed costs and complexity. This was shown using chemical synthesis as an example but is also true for other areas of preclinical research.

Stabilization of enzymes in ionic liquids via modification of enzyme charge.

Science.gov (United States)

Nordwald, Erik M; Kaar, Joel L

2013-09-01

Due to the propensity of ionic liquids (ILs) to inactivate enzymes, the development of strategies to improve enzyme utility in these solvents is critical to fully exploit ILs for biocatalysis. We have developed a strategy to broadly improve enzyme utility in ILs based on elucidating the effect of charge modifications on the function of enzymes in IL environments. Results of stability studies in aqueous-IL mixtures indicated a clear connection between the ratio of enzyme-containing positive-to-negative sites and enzyme stability in ILs. Stability studies of the effect of [BMIM][Cl] and [EMIM][EtSO4 ] on chymotrypsin specifically found an optimum ratio of positively-charged amine-to-negatively-charged acid groups (0.39). At this ratio, the half-life of chymotrypsin was increased 1.6- and 4.3-fold relative to wild-type chymotrypsin in [BMIM][Cl] and [EMIM][EtSO4 ], respectively. The half-lives of lipase and papain were similarly increased as much as 4.0 and 2.4-fold, respectively, in [BMIM][Cl] by modifying the ratio of positive-to-negative sites of each enzyme. More generally, the results of stability studies found that modifications that reduce the ratio of enzyme-containing positive-to-negative sites improve enzyme stability in ILs. Understanding the impact of charge modification on enzyme stability in ILs may ultimately be exploited to rationally engineer enzymes for improved function in IL environments. Copyright © 2013 Wiley Periodicals, Inc.

Artificial Enzymes, "Chemzymes"

DEFF Research Database (Denmark)

Bjerre, Jeannette; Rousseau, Cyril Andre Raphaël; Pedersen, Lavinia Georgeta M

2008-01-01

Enzymes have fascinated scientists since their discovery and, over some decades, one aim in organic chemistry has been the creation of molecules that mimic the active sites of enzymes and promote catalysis. Nevertheless, even today, there are relatively few examples of enzyme models that successf......Enzymes have fascinated scientists since their discovery and, over some decades, one aim in organic chemistry has been the creation of molecules that mimic the active sites of enzymes and promote catalysis. Nevertheless, even today, there are relatively few examples of enzyme models...... that successfully perform Michaelis-Menten catalysis under enzymatic conditions (i.e., aqueous medium, neutral pH, ambient temperature) and for those that do, very high rate accelerations are seldomly seen. This review will provide a brief summary of the recent developments in artificial enzymes, so called...... "Chemzymes", based on cyclodextrins and other molecules. Only the chemzymes that have shown enzyme-like activity that has been quantified by different methods will be mentioned. This review will summarize the work done in the field of artificial glycosidases, oxidases, epoxidases, and esterases, as well...

Economic implications of labor induction.

Science.gov (United States)

Garcia-Simon, Raquel; Montañes, Antonio; Clemente, Jesús; Del Pino, María D; Romero, Manuel A; Fabre, Ernesto; Oros, Daniel

2016-04-01

To assess health service costs associated with labor induction according to different clinical situations in a tertiary-level hospital. In a prospective study, individual patient cost data were assessed for women admitted for induction of labor at a tertiary hospital in Spain between November 1, 2012, and August 31, 2013. The costs of labor induction were estimated according to maternal and neonatal outcomes, method of delivery, cervical condition at admission, and obstetric indication. Direct costs including professional fees, epidural, maternal stay, consumables, and drugs were calculated. Overall, 412 women were included in the final cost analysis. The mean total cost of labor induction was €3589.87 (95% confidence interval [CI] 3475.13-3704.61). Cesarean delivery after labor induction (€4830.45, 95% CI 4623.13-5037.58) was significantly more expensive than spontaneous delivery (€3037.45, 95% CI 2966.91-3179.99) and instrumental vaginal delivery (€3344.31, 95%CI 3151.69-3536.93). The total cost for patients with a very unfavorable cervix (Bishop score Labor induction for hypertensive disorders of pregnancy was the most expensive obstetric indication for induction of labor (€4347.32, 95% CI 3890.45-4804.18). Following the induction of labor, a number of patient- and treatment-related factors influence costs associated with delivery. Copyright © 2015 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Stroke Lesions in a Large Upper Limb Rehabilitation Trial Cohort Rarely Match Lesions in Common Preclinical Models

Science.gov (United States)

Edwardson, Matthew A.; Wang, Ximing; Liu, Brent; Ding, Li; Lane, Christianne J.; Park, Caron; Nelsen, Monica A.; Jones, Theresa A; Wolf, Steven L; Winstein, Carolee J; Dromerick, Alexander W.

2017-01-01

Background Stroke patients with mild-moderate upper extremity (UE) motor impairments and minimal sensory and cognitive deficits provide a useful model to study recovery and improve rehabilitation. Laboratory-based investigators use lesioning techniques for similar goals. Objective Determine whether stroke lesions in an UE rehabilitation trial cohort match lesions from the preclinical stroke recovery models used to drive translational research. Methods Clinical neuroimages from 297 participants enrolled in the Interdisciplinary Comprehensive Arm Rehabilitation Evaluation (ICARE) study were reviewed. Images were characterized based on lesion type (ischemic or hemorrhagic), volume, vascular territory, depth (cortical gray matter, cortical white matter, subcortical), old strokes, and leukoaraiosis. Lesions were compared with those of preclinical stroke models commonly used to study upper limb recovery. Results Among the ischemic stroke participants, median infarct volume was 1.8 mL, with most lesions confined to subcortical structures (61%) including the anterior choroidal artery territory (30%) and the pons (23%). Of ICARE participants, stroke patients, but they represent a clinically and scientifically important subgroup. Compared to lesions in general stroke populations and widely-studied animal models of recovery, ICARE participants had smaller, more subcortically-based strokes. Improved preclinical-clinical translational efforts may require better alignment of lesions between preclinical and human stroke recovery models. PMID:28337932

The effects of gender, age, ethnicity, and liver cirrhosis on cytochrome P450 enzyme activity in human liver microsomes and inducibility in cultured human hepatocytes

International Nuclear Information System (INIS)

Parkinson, Andrew; Mudra, Daniel R.; Johnson, Cory; Dwyer, Anne; Carroll, Kathleen M.

2004-01-01

We have measured cytochrome P450 (CYP) activity in nearly 150 samples of human liver microsomes and 64 samples of cryopreserved human hepatocytes, and we have performed induction studies in over 90 preparations of cultured human hepatocytes. We have analyzed these data to examine whether the expression of CYP enzyme activity in liver microsomes and isolated hepatocytes or the inducibility of CYP enzymes in cultured hepatocytes is influenced by the gender, age, or ethnicity of the donor (the latter being limited to Caucasians, African Americans, and Hispanics due to a paucity of livers from Asian donors). In human liver microsomes, there were no statistically significant differences (P > 0.05) in CYP activity as a function of age, gender, or ethnicity with one exception. 7-Ethoxyresorufin O-dealkylase (CYP1A2) activity was greater in males than females, which is consistent with clinical observation. Liver microsomal testosterone 6β-hydroxylase (CYP3A4) activity was slightly greater in females than males, but the difference was not significant. However, in cryopreserved human hepatocytes, the gender difference in CYP3A4 activity (females = twice males) did reach statistical significance, which supports the clinical observation that females metabolize certain CYP3A4 substrates faster than do males. Compared with those from Caucasians and African Americans, liver microsomes from Hispanics had about twice the average activity of CYP2A6, CYP2B6, and CYP2C8 and half the activity of CYP1A2, although this apparent ethnic difference may be a consequence of the relatively low number of Hispanic donors. Primary cultures of hepatocytes were treated with β-naphthoflavone, an inducer of CYP1A2, phenobarbital or rifampin, both of which induce CYP2B6, CYP2C9, CYP2C19, and CYP3A4, albeit it to different extents. Induction of these CYP enzymes in freshly cultured hepatocytes did not appear to be influenced by the gender or age of the donor. Furthermore, CYP3A4 induction in

Inductive line energy storage generator

Energy Technology Data Exchange (ETDEWEB)

Choi, P [Ecole Polytechnique, Palaiseau (France). Laboratoire de Physique des Milieux Ionises

1997-12-31

The inductive energy storage (IES) generator has long been considered to be the most efficient system for energy usage in large pulsed power system at the MA level. A number of parameters govern the efficiency of energy transfer between the storage capacitors and the load, and the level of current deliverable to the load. For high power system, the energy storage capacitors are arranged as a Marx generator. The primary constraints are the inductances in the various parts of the circuit, in particular, the upstream inductance between the Marx and the POS, and the downstream inductance between the POS and the load. This paper deals with the effect of replacing part of the upstream inductance with a transmission line and introduces the new concept of an inductive line for energy storage (ILES). Extensive parametric scans were carried out on circuit simulations to investigate the effect of this upstream transmission line. A model was developed to explain the operation of the ILES design based on the data obtained. Comparison with an existing IES generator shows that the ILES design offers a significant improvement in the maximum current and hence energy delivered to an inductive load. (author). 5 figs., 1 ref.

Vector control of induction machines

CERN Document Server

Robyns, Benoit

2012-01-01

After a brief introduction to the main law of physics and fundamental concepts inherent in electromechanical conversion, ""Vector Control of Induction Machines"" introduces the standard mathematical models for induction machines - whichever rotor technology is used - as well as several squirrel-cage induction machine vector-control strategies. The use of causal ordering graphs allows systematization of the design stage, as well as standardization of the structure of control devices. ""Vector Control of Induction Machines"" suggests a unique approach aimed at reducing parameter sensitivity for

The Role of Three-Dimensional Scaffolds in Treating Long Bone Defects: Evidence from Preclinical and Clinical Literature-A Systematic Review.

Science.gov (United States)

Roffi, Alice; Krishnakumar, Gopal Shankar; Gostynska, Natalia; Kon, Elizaveta; Candrian, Christian; Filardo, Giuseppe

2017-01-01

Long bone defects represent a clinical challenge. Bone tissue engineering (BTE) has been developed to overcome problems associated with conventional methods. The aim of this study was to assess the BTE strategies available in preclinical and clinical settings and the current evidence supporting this approach. A systematic literature screening was performed on PubMed database, searching for both preclinical (only on large animals) and clinical studies. The following string was used: "(Scaffold OR Implant) AND (Long bone defect OR segmental bone defect OR large bone defect OR bone loss defect)." The search retrieved a total of 1573 articles: 51 preclinical and 4 clinical studies were included. The great amount of preclinical papers published over the past few years showed promising findings in terms of radiological and histological evidence. Unfortunately, this in vivo situation is not reflected by a corresponding clinical impact, with few published papers, highly heterogeneous and with small patient populations. Several aspects should be further investigated to translate positive preclinical findings into clinical protocols: the identification of the best biomaterial, with both biological and biomechanical suitable properties, and the selection of the best choice between cells, GFs, or their combination through standardized models to be validated by randomized trials.

Induction of Liver Steatosis and Lipid Droplet Formation in ATF6α-Knockout Mice Burdened with Pharmacological Endoplasmic Reticulum Stress

OpenAIRE

Harada, Akihiro; Okada, Tetsuya; Sato, Takashi; Mori, Kazutoshi; Yamamoto, Keisuke; Takahara, Kazuna; Oyadomari, Seiichi

2010-01-01

Accumulation of unfolded proteins in the endoplasmic reticulum (ER) activates homeostatic responses collectively termed the unfolded protein response. Among the three principal signaling pathways operating in mammals, activating transcription factor (ATF)6? plays a pivotal role in transcriptional induction of ER-localized molecular chaperones and folding enzymes as well as components of ER-associated degradation, and thereby mouse embryonic fibroblasts deficient in ATF6? are sensitive to ER s...

Designing Preclinical Instruction of Psychomotor Skills (IV)--Instructional Engineering: Evaluation Phase.

Science.gov (United States)

Guenzel, Pamela J.; And Others

1995-01-01

The fourth article in a four-part series on instructional design discusses evaluation of a psychomotor skills unit taught in preclinical dental education. Issues examined include piloting of instructional materials, analysis and revision of materials based on student performance, syllabus design and content, influence of faculty characteristics,…

Inductive Reasoning: A Training Approach

Science.gov (United States)

Klauer, Karl Josef; Phye, Gary D.

2008-01-01

Researchers have examined inductive reasoning to identify different cognitive processes when participants deal with inductive problems. This article presents a prescriptive theory of inductive reasoning that identifies cognitive processing using a procedural strategy for making comparisons. It is hypothesized that training in the use of the…

Inductive Monitoring System (IMS)

Data.gov (United States)

National Aeronautics and Space Administration — IMS: Inductive Monitoring System The Inductive Monitoring System (IMS) is a tool that uses a data mining technique called clustering to extract models of normal...

Rifampin modulation of xeno- and endobiotic conjugating enzyme mRNA expression and associated microRNAs in human hepatocytes.

Science.gov (United States)

Gufford, Brandon T; Robarge, Jason D; Eadon, Michael T; Gao, Hongyu; Lin, Hai; Liu, Yunlong; Desta, Zeruesenay; Skaar, Todd C

2018-04-01

Rifampin is a pleiotropic inducer of multiple drug metabolizing enzymes and transporters. This work utilized a global approach to evaluate rifampin effects on conjugating enzyme gene expression with relevance to human xeno- and endo-biotic metabolism. Primary human hepatocytes from 7 subjects were treated with rifampin (10 μmol/L, 24 hours). Standard methods for RNA-seq library construction, EZBead preparation, and NextGen sequencing were used to measure UDP-glucuronosyl transferase UGT, sulfonyltransferase SULT, N acetyltransferase NAT, and glutathione-S-transferase GST mRNA expression compared to vehicle control (0.01% MeOH). Rifampin-induced (>1.25-fold) mRNA expression of 13 clinically important phase II drug metabolizing genes and repressed (>1.25-fold) the expression of 3 genes ( P  accounting for simultaneous induction of both CYP3A4 and UGT1A4 predicted a ~10-fold decrease in parent midazolam exposure with only a ~2-fold decrease in midazolam N-glucuronide metabolite exposure. These data reveal differential effects of rifampin on the human conjugating enzyme transcriptome and potential associations with miRNAs that form the basis for future mechanistic studies to elucidate the interplay of conjugating enzyme regulatory elements.

Longitudinal trends and subgroup analysis in publication patterns for preclinical data of newly approved drugs.

Science.gov (United States)

Köster, Ursula; Nolte, Ingo; Michel, Martin C

2016-02-01

Having observed a large variation in the number and type of original preclinical publications for newly registered drugs, we have explored whether longitudinal trends and/or factors specific for certain drugs or their manufacturers may explain such variation. Our analysis is based on 1954 articles related to 170 newly approved drugs. The number of preclinical publications per compound declined from a median of 10.5 in 1991 to 3 in 2011. A similar trend was observed for the number of in vivo studies in general, but not in the subset of in vivo studies in animal models of disease. The percentage of compounds with studies using isolated human cells or cell lines almost doubled over time from 37 to 72%. Number of publications did not exhibit major differences between compounds intended for human versus veterinary use, therapeutic areas, small molecules versus biologicals, or innovator versus follow-up compounds; however, some companies may publish fewer studies per compound than others. However, there were qualitative differences in the types of models being used depending on the therapeutic area; specifically, compounds for use in oncology very often used isolated cells and cell lines, often from human origin. We conclude that the large variation in number and type of reported preclinical data is not easily explained. We propose that pharmaceutical companies should consistently provide a comprehensive documentation of the preclinical data they generate as part of their development programs in the public domain to enable a better understanding of the drugs they intend to market.

Epidermal growth factor receptor (EGFR) mutations in lung cancer: preclinical and clinical data

Energy Technology Data Exchange (ETDEWEB)

Jorge, S.E.D.C.; Kobayashi, S.S.; Costa, D.B. [Harvard Medical School, Beth Israel Deaconess Medical Center, Department of Medicine, Division of Hematology/Oncology, Boston, MA (United States)

2014-09-05

Lung cancer leads cancer-related mortality worldwide. Non-small-cell lung cancer (NSCLC), the most prevalent subtype of this recalcitrant cancer, is usually diagnosed at advanced stages, and available systemic therapies are mostly palliative. The probing of the NSCLC kinome has identified numerous nonoverlapping driver genomic events, including epidermal growth factor receptor (EGFR) gene mutations. This review provides a synopsis of preclinical and clinical data on EGFR mutated NSCLC and EGFR tyrosine kinase inhibitors (TKIs). Classic somatic EGFR kinase domain mutations (such as L858R and exon 19 deletions) make tumors addicted to their signaling cascades and generate a therapeutic window for the use of ATP-mimetic EGFR TKIs. The latter inhibit these kinases and their downstream effectors, and induce apoptosis in preclinical models. The aforementioned EGFR mutations are stout predictors of response and augmentation of progression-free survival when gefitinib, erlotinib, and afatinib are used for patients with advanced NSCLC. The benefits associated with these EGFR TKIs are limited by the mechanisms of tumor resistance, such as the gatekeeper EGFR-T790M mutation, and bypass activation of signaling cascades. Ongoing preclinical efforts for treating resistance have started to translate into patient care (including clinical trials of the covalent EGFR-T790M TKIs AZD9291 and CO-1686) and hold promise to further boost the median survival of patients with EGFR mutated NSCLC.

Epidermal growth factor receptor (EGFR) mutations in lung cancer: preclinical and clinical data

International Nuclear Information System (INIS)

Jorge, S.E.D.C.; Kobayashi, S.S.; Costa, D.B.

2014-01-01

Lung cancer leads cancer-related mortality worldwide. Non-small-cell lung cancer (NSCLC), the most prevalent subtype of this recalcitrant cancer, is usually diagnosed at advanced stages, and available systemic therapies are mostly palliative. The probing of the NSCLC kinome has identified numerous nonoverlapping driver genomic events, including epidermal growth factor receptor (EGFR) gene mutations. This review provides a synopsis of preclinical and clinical data on EGFR mutated NSCLC and EGFR tyrosine kinase inhibitors (TKIs). Classic somatic EGFR kinase domain mutations (such as L858R and exon 19 deletions) make tumors addicted to their signaling cascades and generate a therapeutic window for the use of ATP-mimetic EGFR TKIs. The latter inhibit these kinases and their downstream effectors, and induce apoptosis in preclinical models. The aforementioned EGFR mutations are stout predictors of response and augmentation of progression-free survival when gefitinib, erlotinib, and afatinib are used for patients with advanced NSCLC. The benefits associated with these EGFR TKIs are limited by the mechanisms of tumor resistance, such as the gatekeeper EGFR-T790M mutation, and bypass activation of signaling cascades. Ongoing preclinical efforts for treating resistance have started to translate into patient care (including clinical trials of the covalent EGFR-T790M TKIs AZD9291 and CO-1686) and hold promise to further boost the median survival of patients with EGFR mutated NSCLC

Expression of human DNA polymerase β in Escherichia coli and characterization of the recombinant enzyme

International Nuclear Information System (INIS)

Abbotts, J.; SenGupta, D.N.; Zmudzka, B.; Widen, S.G.; Notario, V.; Wilson, S.H.

1988-01-01

The coding region of a human β-polymerase cDNA, predicting a 335 amino acid protein, was subcloned in the Escherichia coli expression plasmid pRC23. After induction of transformed cells, the crude soluble extract was found to contain a new protein immunoreactive with β-polymerase antibody and corresponding in size to the protein deduced from the cDNA. This protein was purified in a yield of 1-2 mg/50 g of cells. The recombinant protein had about the same DNA polymerase specific activity as β-polymerase purified from mammalian tissues, and template-primer specificity and immunological properties of the recombinant polymerase were similar to those of natural β-polymerases. The purified enzyme was free of nuclease activity. The authors studied detailed catalytic properties of the recombinant β-polymerase using defined template-primer systems. The results indicate that this β-polymerase is essentially identical with natural β-polymerases. The recombinant enzyme is distributive in mode of synthesis and is capable of detecting changes in the integrity of the single-stranded template, such as methylated bases and a double-stranded region. The enzyme recognizes a template region four to seven bases downstream of the primer 3' end and utilizes alternative primers if this downstream template region is double stranded. The enzyme is unable to synthesize past methylated bases N 3 -methyl-dT or O 6 -methyl-dG

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

Science.gov (United States)

Ternovoĭ, K S; Kryzhanovskiĭ, G N; Musiĭchuk, Iu I; Noskin, L A; Klopov, N V; Noskin, V A; Starodub, N F

1998-01-01

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.

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

Directory of Open Access Journals (Sweden)

Eugene Michel

2011-01-01

Full Text Available Abstract 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 β-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.

Enzyme detection by microfluidics

DEFF Research Database (Denmark)

2013-01-01

Microfluidic-implemented methods of detecting an enzyme, in particular a DNA-modifying enzyme, are provided, as well as methods for detecting a cell, or a microorganism expressing said enzyme. The enzyme is detected by providing a nucleic acid substrate, which is specifically targeted...... by that enzyme...

Effect of Inductive Coil Shape on Sensing Performance of Linear Displacement Sensor Using Thin Inductive Coil and Pattern Guide

Directory of Open Access Journals (Sweden)

Hiroyuki Wakiwaka

2011-11-01

Full Text Available This paper discusses the effect of inductive coil shape on the sensing performance of a linear displacement sensor. The linear displacement sensor consists of a thin type inductive coil with a thin pattern guide, thus being suitable for tiny space applications. The position can be detected by measuring the inductance of the inductive coil. At each position due to the change in inductive coil area facing the pattern guide the value of inductance is different. Therefore, the objective of this research is to study various inductive coil pattern shapes and to propose the pattern that can achieve good sensing performance. Various shapes of meander, triangular type meander, square and circle shape with different turn number of inductive coils are examined in this study. The inductance is measured with the sensor sensitivity and linearity as a performance evaluation parameter of the sensor. In conclusion, each inductive coil shape has its own advantages and disadvantages. For instance, the circle shape inductive coil produces high sensitivity with a low linearity response. Meanwhile, the square shape inductive coil has a medium sensitivity with higher linearity.

Mercury induced oxidative stress, DNA damage, and activation of antioxidative system and Hsp70 induction in duckweed (Lemna minor).

Science.gov (United States)

Zhang, Tingting; Lu, Qianqian; Su, Chunlei; Yang, Yaru; Hu, Dan; Xu, Qinsong

2017-09-01

Mercury uptake and its effects on physiology, biochemistry and genomic stability were investigated in Lemna minor after 2 and 6d of exposure to 0-30μM Hg. The accumulation of Hg increased in a concentration- and duration-dependent manner, and was positively correlated with the leaf damage. Oxidative stress after Hg exposure was evidenced in L. minor by a significant decrease in photosynthetic pigments, an increase in malondialdehyde and lipoxygenase activities (total enzyme activity and isoenzymes activity). Fronds of L. minor exposed to Hg showed an induction of peroxidase, catalase, and ascorbate peroxidase activities (total enzyme activity and some isoenzymes activities). Exposure of L. minor to Hg reduced the activity (total enzyme activity and some isoenzymes activities) of glutathione reductase, and superoxide dismutase. Exposure to Hg produced a transient increase in the content of glutathione and ascorbic acid. The content of dehydroascorbate and oxidized glutathione in L. minor were high during the entire exposure period. Exposure of L. minor to Hg also caused the accumulation of proline and soluble sugars. The amplification of new bands and the absence of normal DNA amplicons in treated plants in the random amplified polymorphic DNA (RAPD) profile indicated that genomic template stability (GTS) was affected by Hg treatment. The accumulation of Hsp70 indicated the occurrence of a heat shock response at all Hg concentrations. These results suggest that L. minor plants were able to cope with Hg toxicity through the activation of various mechanisms involving enzymatic and non-enzymatic antioxidants, up-regulation of proline, and induction of Hsp70. Copyright © 2017 Elsevier Inc. All rights reserved.

[Enzyme inductive effect of zixoryn (3-trifluoromethyl-alpha-ethyl-benzhydrol) in neonatal jaundice].

Science.gov (United States)

Korányi, G; Boross, G

1985-02-01

Zixoryn, (3-trifluoromethyl-alfa-aethyl-benzhydrole) is a new product of the Hungarian Chemical Works of Gedeon Richter Ltd. It induces the mixed function oxydase enzyme system of the endoplasmic reticulum of the liver and has no other pharmacological effects. We have studied the effect of Zixoryn on early hyperbilirubin-aemia. 42 neonates were studied, 21 of them were randomly assigned to be treated and the others served as control group Zixoryn treatment consisted of drops containing 10 mg Zixoryn per ml in a single 20 mg/kg body weight dose through a gastric tube. Results are summarized in Fig. 2. It shows the mean se bi levels during the first six days of life. It is remarkable that the decline of se bi level was much faster in the treated than in the control group. On the third day the difference between the two groups was significant. We may conclude that after Zixoryn administration the se bi level of otherwise healthy newborns decreased significantly faster than that of untreated neonates. No side-effects what so ever were observed. The administration is easy, a single oral dose has a satisfactory effect.

Induction of DNA double-strand breaks by restriction enzymes in X-ray-sensitive mutant Chinese hamster ovary cells measured by pulsed-field gel electrophoresis

International Nuclear Information System (INIS)

Kinashi, Yuko; Nagasawa, Hatsumi; Little, J.B.; Okayasu, Ryuichi; Iliakis, G.E.

1995-01-01

This investigation was designed to determine whether the cytotoxic effects of different restriction endonucleases are related to the number and type of DNA double-strand breaks (DSBs) they produce. Chinese hamster ovary (CHO) K1 and xrs-5 cells, a radiosensitive mutant of CHO K1, were exposed to restriction endonucleases HaeIII, HinfI, PvuII and BamHI by electroporation. These enzymes represent both blunt and sticky end cutters with differing recognition sequence lengths. The number of DSBs was measured by pulsed-field gel electrophoresis (PFGE). Two forms of PFGE were employed: asymmetric field-inversion gel electrophoresis (AFIGE) for measuring the kinetics of DNA breaks by enzyme digestion and clamped homogeneous gel electrophoresis (CHEF) for examining the size distributions of damaged DNA. The amount of DNA damage induced by exposure to all four restriction enzymes was significantly greater in xrs-5 compared to CHO K1 cells, consistent with the reported DSB repair deficiency in these cells. Since restriction endonucleases produce DSBs alone as opposed to the various types of DNA damage induced by X rays, these results confirm that the repair defect in this mutant involves the rejoining of DSBs. Although the cutting frequency was directly related to the length of the recognition sequence for four restriction enzymes, there was no simple correlation between the cytotoxic effect and the amount of DNA damage produced by each enzyme in either cell line. This finding suggests that the type or nature of the cutting sequence itself may play a role in restriction enzyme-induced cell killing. 32 refs., 6 figs., 3 tabs

Preclinical Science Regarding Cannabinoids as Analgesics: An Overview

Directory of Open Access Journals (Sweden)

ME Lynch

2005-01-01

Full Text Available Modern pharmacology of cannabinoids began in 1964 with the isolation and partial synthesis of delta-9-tetrahydrocannabinol, the main psychoactive agent in herbal cannabis. Since then, potent antinociceptive and antihyperalgesic effects of cannabinoid agonists in animal models of acute and chronic pain; the presence of cannabinoid receptors in pain-processing areas of the brain, spinal cord and periphery; and evidence supporting endogenous modulation of pain systems by cannabinoids has provided support that cannabinoids exhibit significant potential as analgesics. The present article presents an overview of the preclinical science.

Preclinical Models in Chimeric Antigen Receptor-Engineered T-Cell Therapy.

Science.gov (United States)

Siegler, Elizabeth Louise; Wang, Pin

2018-05-01

Cancer immunotherapy has enormous potential in inducing long-term remission in cancer patients, and chimeric antigen receptor (CAR)-engineered T cells have been largely successful in treating hematological malignancies in the clinic. CAR-T therapy has not been as effective in treating solid tumors, in part due to the immunosuppressive tumor microenvironment. Additionally, CAR-T therapy can cause dangerous side effects, including off-tumor toxicity, cytokine release syndrome, and neurotoxicity. Animal models of CAR-T therapy often fail to predict such adverse events and frequently overestimate the efficacy of the treatment. Nearly all preclinical CAR-T studies have been performed in mice, including syngeneic, xenograft, transgenic, and humanized mouse models. Recently, a few studies have used primate models to mimic clinical side effects better. To date, no single model perfectly recapitulates the human immune system and tumor microenvironment, and some models have revealed CAR-T limitations that were contradicted or missed entirely in other models. Careful model selection based on the primary goals of the study is a crucial step in evaluating CAR-T treatment. Advancements are being made in preclinical models, with the ultimate objective of providing safer, more effective CAR-T therapy to patients.

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

Directory of Open Access Journals (Sweden)

Samarasekera Dharmabandu N

2011-05-01

Full Text Available Abstract Background Students can be classified into three categories depending on their approaches to studying; namely, deep approach (DA, strategic approach (SA and surface apathetic or superficial approach (SAA. The aim of this study was to identify factors affecting the approaches to studying among Sri Lankan medical undergraduates and post graduate trainees and to analyze the change in the pattern of study skills with time and experience. Method Pre-clinical and clinical students of the Faculty of Medicine, University of Colombo and postgraduate trainees in Surgery at the National Hospital of Sri Lanka were invited to complete the Approaches and Study Skills Inventory for Students (ASSIST questionnaire. Results A total of 187 pre clinical (M: F = 96:91, 124 clinical (M: F = 61:63 and 53 post graduate trainees (M: F = 50:3 participated in the study. Approaches of male and female students were similar. SA was significantly affected by age among the preclinical students (p = 0.01, but not in other groups. Among pre-clinical students, males preferred a teacher who supported understanding (p = 0.04 but females preferred a passive transmission of information (p Conclusion Different factors affect the approach to studying in different groups but these explain only a small fraction of the variance observed.

The preclinical discovery and development of quetiapine for the treatment of mania and depression.

Science.gov (United States)

Miranda, Aline Silva de; Moreira, Fabrício A; Teixeira, Antônio Lúcio

2017-05-01

Bipolar disorder is a chronic disabling condition characterized by alternating manic and depressive episodes. Bipolar disorder has been associated with functional impairment, poor quality of life, morbidity and mortality. Despite its significant clinical, social and economic burden, treatment options for bipolar disorder are still limited. Several clinical trials have shown efficacy of the atypical antipsychotic quetiapine (QTP) in the treatment of this condition. However, the mechanisms underlying the antidepressant and anti-manic effects of QTP remain poorly understood. Areas covered: The article provides the emerging evidence from pre-clinical studies regarding the antidepressant and anti-manic mechanisms of action of QTP. In combination with its primary active metabolite norquetiapine, QTP modulates several neurotransmitter systems, including serotonin, dopamine, noradrenaline and histamine. QTP also seems to influence mediators of the immune system. Expert opinion: Pre-clinical studies have provided valuable information on the potential antidepressant mechanisms of action of QTP, but pre-clinical studies on QTP's anti-manic effects are still scarce. A major problem refers to the lack of valid experimental models for bipolar disorder. Additionally, immune and genetic based studies are largely descriptive. The role of the QTP metabolite norquetiapine in modulating non-neurotransmitter systems also needs to be further addressed.

Characteristic single glucosinolates from Moringa oleifera: Induction of detoxifying enzymes and lack of genotoxic activity in various model systems.

Science.gov (United States)

Förster, Nadja; Mewis, Inga; Glatt, Hansruedi; Haack, Michael; Brigelius-Flohé, Regina; Schreiner, Monika; Ulrichs, Christian

2016-11-09

Leaves of Moringa oleifera are used by tribes as biological cancer medicine. Scientific investigations with M. oleifera conducted so far have almost exclusively used total plant extracts. Studies on the activity of single compounds are missing. Therefore, the biological effects of the two main aromatic multi-glycosylated glucosinolates of M. oleifera were investigated in the present study. The cytotoxic effects of M. oleifera glucosinolates were identified for HepG2 cells (NRU assay), for V79-MZ cells (HPRT assay, SCE assay), and for two Salmonella typhimurium strains (Ames test). Genotoxic effects of these glucosinolates were not observed (Ames test, HPRT assay, and SCE assay). Reporter gene assays revealed a significant increase in the ARE-dependent promoter activity of NQO1 and GPx2 indicating an activation of the Nrf2 pathway by M. oleifera glucosinolates. Since both enzymes can also be induced via activation of the AhR, plasmids containing promoters of both enzymes mutated in the respective binding sites (pGL3enh-hNQO1-ARE, pGL3enh-hNQO1-XRE, pGL3bas-hGPX2-mutARE, pGL3bas-hGPX2-mutXRE) were transfected. Analyses revealed that the majority of the stimulating effects was mediated by the ARE motif, whereas the XRE motif played only a minor role. The stimulating effects of M. oleifera glucosinolates could be demonstrated both at the transcriptional (reporter gene assay, real time-PCR) and translational levels (enzyme activity) making them interesting compounds for further investigation.

Anesthetic neuroprotection: antecedents and an appraisal of preclinical and clinical data quality.

Science.gov (United States)

Ishida, Kazuyoshi; Berger, Miles; Nadler, Jacob; Warner, David S

2014-01-01

Anesthetics have been studied for nearly fifty years as potential neuroprotective compounds in both perioperative and resuscitation medicine. Although anesthetics present pharmacologic properties consistent with preservation of brain viability in the context of an ischemic insult, no anesthetic has been proven efficacious for neuroprotection in humans. After such effort, it could be concluded that anesthetics are simply not neuroprotective in humans. Moreover, pharmacologic neuroprotection with non-anesthetic drugs has also repeatedly failed to be demonstrated in human acute brain injury. Recent focus has been on rectification of promising preclinical neuroprotection data and subsequent failed clinical trials. This has led to consensus guidelines for the process of transferring purported therapeutics from bench to bedside. In this review we first examined the history of anesthetic neuroprotection research. Then, a systematic review was performed to identify major clinical trials of anesthetic neuroprotection. Both the preclinical neuroprotection portfolio cited to justify a clinical trial and the design and conduct of that clinical trial were evaluated using modern standards that include the Stroke Therapy Academic Industry Roundtable (STAIR) and Consolidated Standards of Reporting Trials (CONSORT) guidelines. In publications intended to define anesthetic neuroprotection, we found overall poor quality of both preclinical efficacy analysis portfolios and clinical trial designs and conduct. Hence, using current translational research standards, it was not possible to conclude from existing data whether anesthetics ameliorate perioperative ischemic brain injury. Incorporation of advances in translational neuroprotection research conduct may provide a basis for more definitive and potentially successful clinical trials of anesthetics as neuroprotectants.

7 CFR 58.436 - Rennet, pepsin, other milk clotting enzymes and flavor enzymes.

Science.gov (United States)

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436 Section 58.436 Agriculture Regulations of the Department of Agriculture (Continued... clotting enzymes and flavor enzymes. Enzyme preparations used in the manufacture of cheese shall be safe...

Elevated Liver Enzymes

Science.gov (United States)

Symptoms Elevated liver enzymes By Mayo Clinic Staff Elevated liver enzymes may indicate inflammation or damage to cells in the liver. Inflamed or ... than normal amounts of certain chemicals, including liver enzymes, into the bloodstream, which can result in elevated ...

Stability of Enzymes in Granular Enzyme Products for Laundry Detergents

DEFF Research Database (Denmark)

Biran, Suzan; Bach, Poul; Simonsen, Ole

Enzymes have long been of interest to the detergent industry due to their ability to improve the cleaning efficiency of synthetic detergents, contribute to shortening washing times, and reduce energy and water consumption, provision of environmentally friendlier wash water effluents and fabric care....... However, incorporating enzymes in detergent formulations gives rise to numerous practical problems due to their incompatibility with and stability against various detergent components. In powdered detergent formulations, these issues can be partly overcome by physically isolating the enzymes in separate...... particles. However, enzymes may loose a significant part of their activity over a time period of several weeks. Possible causes of inactivation of enzymes in a granule may be related to the release of hydrogen peroxide from the bleaching chemicals in a moisture-containing atmosphere, humidity, autolysis...

Enhanced thyroid hormone breakdown in hepatocytes by mutual induction of the constitutive androstane receptor (CAR, NR1I3) and arylhydrocarbon receptor by benzo[a]pyrene and phenobarbital.

Science.gov (United States)

Schraplau, Anne; Schewe, Bettina; Neuschäfer-Rube, Frank; Ringel, Sebastian; Neuber, Corinna; Kleuser, Burkhard; Püschel, Gerhard P

2015-02-03

Xenobiotics may interfere with the hypothalamic-pituitary-thyroid endocrine axis by inducing enzymes that inactivate thyroid hormones and thereby reduce the metabolic rate. This induction results from an activation of xeno-sensing nuclear receptors. The current study shows that benzo[a]pyrene, a frequent contaminant of processed food and activator of the arylhydrocarbon receptor (AhR) activated the promoter and induced the transcription of the nuclear receptor constitutive androstane receptor (CAR, NR1I3) in rat hepatocytes. Likewise, phenobarbital induced the AhR transcription. This mutual induction of the nuclear receptors enhanced the phenobarbital-dependent induction of the prototypic CAR target gene Cyp2b1 as well as the AhR-dependent induction of UDP-glucuronosyltransferases. In both cases, the induction by the combination of both xenobiotics was more than the sum of the induction by either substance alone. By inducing the AhR, phenobarbital enhanced the benzo[a]pyrene-dependent reduction of thyroid hormone half-life and the benzo[a]pyrene-dependent increase in the rate of thyroid hormone glucuronide formation in hepatocyte cultures. CAR ligands might thus augment the endocrine disrupting potential of AhR activators by an induction of the AhR. Copyright © 2014. Published by Elsevier Ireland Ltd.

Use of Preclinical Drug vs. Food Choice Procedures to Evaluate Candidate Medications for Cocaine Addiction.

Science.gov (United States)

Banks, Matthew L; Hutsell, Blake A; Schwienteck, Kathryn L; Negus, S Stevens

2015-06-01

Drug addiction is a disease that manifests as an inappropriate allocation of behavior towards the procurement and use of the abused substance and away from other behaviors that produce more adaptive reinforcers (e.g. exercise, work, family and social relationships). The goal of treating drug addiction is not only to decrease drug-maintained behaviors, but also to promote a reallocation of behavior towards alternative, nondrug reinforcers. Experimental procedures that offer concurrent access to both a drug reinforcer and an alternative, nondrug reinforcer provide a research tool for assessment of medication effects on drug choice and behavioral allocation. Choice procedures are currently the standard in human laboratory research on medications development. Preclinical choice procedures have been utilized in biomedical research since the early 1940's, and during the last 10-15 years, their use for evaluation of medications to treat drug addiction has increased. We propose here that parallel use of choice procedures in preclinical and clinical studies will facilitate translational research on development of medications to treat cocaine addiction. In support of this proposition, a review of the literature suggests strong concordance between preclinical effectiveness of candidate medications to modify cocaine choice in nonhuman primates and rodents and clinical effectiveness of these medications to modify either cocaine choice in human laboratory studies or metrics of cocaine abuse in patients with cocaine use disorder. The strongest evidence for medication effectiveness in preclinical choice studies has been obtained with maintenance on the monoamine releaser d -amphetamine, a candidate agonist medication for cocaine use analogous to use of methadone to treat heroin abuse or nicotine formulations to treat tobacco dependence.

Striatal dopamine D2 receptors, metabolism, and volume in preclinical Huntington disease

NARCIS (Netherlands)

van Oostrom, JCH; Maguire, RP; Verschuuren-Bemelmans, CC; van der Duin, LV; Pruim, J; Roos, RAC; Leenders, KL

2005-01-01

Among 27 preclinical carriers of the Huntington disease mutation (PMC), the authors found normal striatal values for MRI volumetry in 88% and for fluorodesoxyglucose PET metabolic index in 67%. Raclopride PET binding potential (RAC-BP) was decreased in 50% and correlated with increases in the

One-year monitoring of core biomarker and digestive enzyme responses in transplanted zebra mussels (Dreissena polymorpha).

Science.gov (United States)

Palais, F; Dedourge-Geffard, O; Beaudon, A; Pain-Devin, S; Trapp, J; Geffard, O; Noury, P; Gourlay-Francé, C; Uher, E; Mouneyrac, C; Biagianti-Risbourg, S; Geffard, A

2012-04-01

A 12-month active biomonitoring study was performed in 2008-2009 on the Vesle river basin (Champagne-Ardenne, France) using the freshwater mussel Dreissena polymorpha as a sentinel species; allochthonous mussels originating from a reference site (Commercy) were exposed at four sites (Bouy, Sept-Saulx, Fismes, Ardre) within the Vesle river basin. Selected core biomarkers (acetylcholinesterase (AChE) activity, glutathione-S transferase (GST) activity, metallothionein concentration), along with digestive enzyme activities (amylase, endocellulase) and energy reserve concentrations (glycogen, lipids), were monitored throughout the study in exposed mussels. At the Fismes and Ardre sites (downstream basin), metallic and organic contamination levels were low but still high enough to elicit AChE and GST activity induction in exposed mussels (chemical stress); besides, chemical pollutants had no apparent deleterious effects on mussel condition. At the Bouy and Sept-Saulx sites (upstream basin), mussels obviously suffered from adverse food conditions which seriously impaired individual physiological state and survival (nutritional stress); food scarcity had however no apparent effects on core biomarker responses. Digestive enzyme activities responded to both chemical and nutritional stresses, the increase in energy outputs (general adaptation syndrome-downstream sites) or the decrease in energy inputs (food scarcity-upstream sites) leading to mid- or long-term induction of digestive carbohydrase activities in exposed mussels (energy optimizing strategy). Complex regulation patterns of these activities require nevertheless the use of a multi-marker approach to allow data interpretation. Besides, their sensitivity to natural confounding environmental factors remains to be precised.

Enzyme structure, enzyme function and allozyme diversity in ...

African Journals Online (AJOL)

In estimates of population genetic diversity based on allozyme heterozygosity, some enzymes are regularly more variable than others. Evolutionary theory suggests that functionally less important molecules, or parts of molecules, evolve more rapidly than more important ones; the latter enzymes should then theoretically be ...

Enzyme sensitive liposomes in chemotherapy and potentiation of immunotherapy

DEFF Research Database (Denmark)

Østrem, Ragnhild Garborg

efficacy and induction of severe adverse effects. Interestingly, the pharmacokinetics and biodistribution of drugs can be substantially altered by encapsulation in liposomal drug delivery vehicles. The first chapter of this thesis gives a brief introduction to cancer followed by a discussion...... of the applicability of liposomes as drug delivery vehicles in cancer therapy. The second chapter describes the development of a liposome system with an inbuilt release mechanism triggered by secretory phospholipase A2 (sPLA2). This enzyme is expressed at elevated levels in many human cancers, and as such represents...... with an introduction to the cancer-immunity cycle and to how treatment approaches can aid this interplay. Subsequently it demonstrates that the presence of a functional immune system is important in the efficacy of liposomal oxaliplatin, and that this efficacy can be substantially enhanced by combination with...

Ethical Considerations of Preclinical Testing

Directory of Open Access Journals (Sweden)

Allen Goldenthal

2015-12-01

Full Text Available The numbers of animal tests being conducted are on a sharp incline.  Much of this increase is directly due to our ability to generate transgenic models and knock-outs, thereby increasing the validity of the animal model but not necessarily correlating directly with any translational medical benefits to the human counterpart.  In spite of our best efforts, there still exist species differences that prevent the application directly from animal to human, and in some examples having a completely different and adverse effect from that seen in the animal model. There are several ways in which we can improve the opportunity for a positive test outcome and at the same time reduce the animal usage which is associated with our current animal testing practices. The benefit of the 3R’s is that they encourage us not only to avoid wastage of life but that they require us to provide considerable foresight and extrapolated thought before directly engaging in the preclinical testing phase.

Modeling of drug-mediated CYP3A4 induction by using human iPS cell-derived enterocyte-like cells

International Nuclear Information System (INIS)

Negoro, Ryosuke; Takayama, Kazuo; Nagamoto, Yasuhito; Sakurai, Fuminori; Tachibana, Masashi; Mizuguchi, Hiroyuki

2016-01-01

Many drugs have potential to induce the expression of drug-metabolizing enzymes, particularly cytochrome P450 3A4 (CYP3A4), in small intestinal enterocytes. Therefore, a model that can accurately evaluate drug-mediated CYP3A4 induction is urgently needed. In this study, we overlaid Matrigel on the human induced pluripotent stem cells-derived enterocyte-like cells (hiPS-ELCs) to generate the mature hiPS-ELCs that could be applied to drug-mediated CYP3A4 induction test. By overlaying Matrigel in the maturation process of enterocyte-like cells, the gene expression levels of intestinal markers (VILLIN, sucrase-isomaltase, intestine-specific homeobox, caudal type homeobox 2, and intestinal fatty acid-binding protein) were enhanced suggesting that the enterocyte-like cells were maturated by Matrigel overlay. The percentage of VILLIN-positive cells in the hiPS-ELCs found to be approximately 55.6%. To examine the CYP3A4 induction potential, the hiPS-ELCs were treated with various drugs. Treatment with dexamethasone, phenobarbital, rifampicin, or 1α,25-dihydroxyvitamin D3 resulted in 5.8-fold, 13.4-fold, 9.8-fold, or 95.0-fold induction of CYP3A4 expression relative to that in the untreated controls, respectively. These results suggest that our hiPS-ELCs would be a useful model for CYP3A4 induction test. - Highlights: • The hiPS-ELCs were matured by Matrigel overlay. • The hiPS-ELCs expressed intestinal nuclear receptors, such as PXR, GR and VDR. • The hiPS-ELC is a useful model for the drug-mediated CYP3A4 induction test.

Modeling of drug-mediated CYP3A4 induction by using human iPS cell-derived enterocyte-like cells

Energy Technology Data Exchange (ETDEWEB)

Negoro, Ryosuke [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Takayama, Kazuo [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); The Keihanshin Consortium for Fostering the Next Generation of Global Leaders in Research (K-CONNEX), Kyoto University, Kyoto 606-8302 (Japan); Laboratory of Hepatocyte Regulation, National Institute of Biomedical Innovation, Health and Nutrition, Osaka 567-0085 (Japan); Nagamoto, Yasuhito [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Laboratory of Hepatocyte Regulation, National Institute of Biomedical Innovation, Health and Nutrition, Osaka 567-0085 (Japan); Sakurai, Fuminori [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Laboratory of Regulatory Sciences for Oligonucleotide Therapeutics, Clinical Drug Development Project, Graduate School of Pharmaceutical Sciences, Osaka University Osaka 565-0871 (Japan); Tachibana, Masashi [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Mizuguchi, Hiroyuki, E-mail: mizuguch@phs.osaka-u.ac.jp [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Laboratory of Hepatocyte Regulation, National Institute of Biomedical Innovation, Health and Nutrition, Osaka 567-0085 (Japan); Global Center for Medical Engineering and Informatics, Osaka University, Osaka 565-0871 (Japan)

2016-04-15

Many drugs have potential to induce the expression of drug-metabolizing enzymes, particularly cytochrome P450 3A4 (CYP3A4), in small intestinal enterocytes. Therefore, a model that can accurately evaluate drug-mediated CYP3A4 induction is urgently needed. In this study, we overlaid Matrigel on the human induced pluripotent stem cells-derived enterocyte-like cells (hiPS-ELCs) to generate the mature hiPS-ELCs that could be applied to drug-mediated CYP3A4 induction test. By overlaying Matrigel in the maturation process of enterocyte-like cells, the gene expression levels of intestinal markers (VILLIN, sucrase-isomaltase, intestine-specific homeobox, caudal type homeobox 2, and intestinal fatty acid-binding protein) were enhanced suggesting that the enterocyte-like cells were maturated by Matrigel overlay. The percentage of VILLIN-positive cells in the hiPS-ELCs found to be approximately 55.6%. To examine the CYP3A4 induction potential, the hiPS-ELCs were treated with various drugs. Treatment with dexamethasone, phenobarbital, rifampicin, or 1α,25-dihydroxyvitamin D3 resulted in 5.8-fold, 13.4-fold, 9.8-fold, or 95.0-fold induction of CYP3A4 expression relative to that in the untreated controls, respectively. These results suggest that our hiPS-ELCs would be a useful model for CYP3A4 induction test. - Highlights: • The hiPS-ELCs were matured by Matrigel overlay. • The hiPS-ELCs expressed intestinal nuclear receptors, such as PXR, GR and VDR. • The hiPS-ELC is a useful model for the drug-mediated CYP3A4 induction test.

Exposure to an environment containing the aromatic red cedar, Juniperus virginiana: procarcinogenic, enzyme-inducing and insecticidal effects.

Science.gov (United States)

Sabine, J R

1975-11-01

(1) Shavings from the Eastern Red Cedar (Juniperus virginiana) were examined for three diverse biological properties, i.e. enzyme induction, procarcinogenicity and insecticidal activity. (2) The ability of a cedar environment to stimulate liver drug-metabolizing enzymes in mice was confirmed by lowered values for barbiturate sleeping time. (3) In susceptible strains of mice (C3H-Avy, C3H-AvyfB and CBA/J) the use of cedar shavings as bedding increased significantly the incidence of spontaneous tumors of the liver and mammary gland, and also reduced the average time at which tumors appeared. (4) Cedar and some of its derivatives (Oil of Cedarwood, cedrene, cedrol) disrupted the reproductive and developmental cycle of a number of insects, including the Peanut Trash Bug (Elasmolomus sordidus), the Indian Meal Moth (Plodia interpunctella) and the Forage Mite (Tyrophagus putrescentiae).

Urofollitropin and ovulation induction

NARCIS (Netherlands)

van Wely, Madelon; Yding Andersen, Claus; Bayram, Neriman; van der Veen, Fulco

2005-01-01

Anovulation is a common cause of female infertility. Treatment for women with anovulation is aimed at induction of ovulation. Ovulation induction with follicle-stimulating hormone (FSH) is indicated in women with WHO type II anovulation in whom treatment with clomifene citrate (clomifene) has

O-Alkyl Hydroxamates as Metaphors of Enzyme-Bound Enolate Intermediates in Hydroxy Acid Dehydrogenases. Inhibitors of Isopropylmalate Dehydrogenase, Isocitrate Dehydrogenase, and Tartrate Dehydrogenase(1).

Science.gov (United States)

Pirrung, Michael C.; Han, Hyunsoo; Chen, Jrlung

1996-07-12

The inhibition of Thermus thermophilus isopropylmalate dehydrogenase by O-methyl oxalohydroxamate was studied for comparison to earlier results of Schloss with the Salmonella enzyme. It is a fairly potent (1.2 &mgr;M), slow-binding, uncompetitive inhibitor against isopropylmalate and is far superior to an oxamide (25 mM K(i) competitive) that is isosteric with the ketoisocaproate product of the enzyme. This improvement in inhibition was attributed to its increased NH acidity, which presumably is due to the inductive effect of the hydroxylamine oxygen. This principle was extended to the structurally homologous enzyme isocitrate dehydrogenase from E. coli, for which the compound O-(carboxymethyl) oxalohydroxamate is a 30 nM inhibitor, uncompetitive against isocitrate. The pH dependence of its inhibition supports the idea that it is bound to the enzyme in the anionic form. Another recently discovered homologous enzyme, tartrate dehydrogenase from Pseudomonas putida, was studied with oxalylhydroxamate. It has a relatively low affinity for the enzyme, though it is superior to tartrate. On the basis of these leads, squaric hydroxamates with increased acidity compared to squaric amides directed toward two of these enzymes were prepared, and they also show increased inhibitory potency, though not approaching the nanomolar levels of the oxalylhydroxamates.

The prevalence and consequences of burnout on a group of preclinical dental students.

Science.gov (United States)

Atalayin, Cigdem; Balkis, Murat; Tezel, Huseyin; Onal, Banu; Kayrak, Gul

2015-01-01

The aim of this study is to investigate the prevalence of burnout among a group of Turkish preclinical dental students, to compare the level of burnout and to determine the consequences in structural equation model. Preclinical dental students (n = 329, 50.5% of females and 49.5% of males) aged between 18 and 24 took part in the study. Maslach burnout inventory student version, academic satisfaction scale, and personal information sheet were used to gather data. Pearson correlation analyses, t-test, and one-way ANOVA were used for statistical analysis. The proposed theoretical model was tested via observed variable path analysis using maximum likelihood parameter estimation with AMOS 7.0. About 22.3% of students had high level of emotional exhaustion, 16.7% of students had high level of cynicism, and 17.9% of students suffered from high level of reduced academic efficacy. While the students attending the first grade reported higher level of reduced academic efficacy, the students in the third grade reported higher level of emotional exhaustion. Academic workload played an important role in the development of burnout. As consequences of burnout, students with high levels of burnout intended to change their current major and did not to plan to continue to postgraduate education. Students with high level of burnout reported less level of academic satisfaction and academic achievement. Creating awareness on the burnout of dental students from the preclinical period may be useful for prevention and more compatible dental education environment.

The Australian Medical Schools Assessment Collaboration: benchmarking the preclinical performance of medical students.

Science.gov (United States)

O'Mara, Deborah A; Canny, Ben J; Rothnie, Imogene P; Wilson, Ian G; Barnard, John; Davies, Llewelyn

2015-02-02

To report the level of participation of medical schools in the Australian Medical Schools Assessment Collaboration (AMSAC); and to measure differences in student performance related to medical school characteristics and implementation methods. Retrospective analysis of data using the Rasch statistical model to correct for missing data and variability in item difficulty. Linear model analysis of variance was used to assess differences in student performance. 6401 preclinical students from 13 medical schools that participated in AMSAC from 2011 to 2013. Rasch estimates of preclinical basic and clinical science knowledge. Representation of Australian medical schools and students in AMSAC more than doubled between 2009 and 2013. In 2013 it included 12 of 19 medical schools and 68% of medical students. Graduate-entry students scored higher than students entering straight from school. Students at large schools scored higher than students at small schools. Although the significance level was high (P performance. The effect on performance of multiple assessments compared with the test items as part of a single end-of-year examination was negligible. The variables investigated explain only 12% of the total variation in student performance. An increasing number of medical schools are participating in AMSAC to monitor student performance in preclinical sciences against an external benchmark. Medical school characteristics account for only a small part of overall variation in student performance. Student performance was not affected by the different methods of administering test items.

Spinal Cord Tolerance in the Age of Spinal Radiosurgery: Lessons From Preclinical Studies

International Nuclear Information System (INIS)

Medin, Paul M.; Boike, Thomas P.

2011-01-01

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

Perceptions of Teaching Methods for Preclinical Oral Surgery: A Comparison with Learning Styles.

Science.gov (United States)

Omar, Esam

2017-01-01

Dental extraction is a routine part of clinical dental practice. For this reason, understanding the way how students' extraction knowledge and skills development are important. To date, there is no accredited statement about the most effective method for the teaching of exodontia to dental students. Students have different abilities and preferences regarding how they learn and process information. This is defined as learning style. In this study, the effectiveness of active learning in the teaching of preclinical oral surgery was examined. The personality type of the groups involved in this study was determined, and the possible effect of personality type on learning style was investigated. This study was undertaken over five years from 2011 to 2015. The sample consisted of 115 students and eight staff members. Questionnaires were submitted by 68 students and all eight staff members involved. Three measures were used in the study: The Index of Learning Styles (Felder and Soloman, 1991), the Myers-Briggs Type Indicator (MBTI), and the styles of learning typology (Grasha and Hruska-Riechmann). Findings indicated that demonstration and minimal clinical exposure give students personal validation. Frequent feedback on their work is strongly indicated to build the cognitive, psychomotor, and interpersonal skills needed from preclinical oral surgery courses. Small group cooperative active learning in the form of demonstration and minimal clinical exposure that gives frequent feedback and students' personal validation on their work is strongly indicated to build the skills needed for preclinical oral surgery courses.

Doxorubicin-mediated bone loss in breast cancer bone metastases is driven by an interplay between oxidative stress and induction of TGFβ.

Directory of Open Access Journals (Sweden)

Tapasi Rana

Full Text Available Breast cancer patients, who are already at increased risk of developing bone metastases and osteolytic bone damage, are often treated with doxorubicin. Unfortunately, doxorubicin has been reported to induce damage to bone. Moreover, we have previously reported that doxorubicin treatment increases circulating levels of TGFβ in murine pre-clinical models. TGFβ has been implicated in promoting osteolytic bone damage, a consequence of increased osteoclast-mediated resorption and suppression of osteoblast differentiation. Therefore, we hypothesized that in a preclinical breast cancer bone metastasis model, administration of doxorubicin would accelerate bone loss in a TGFβ-mediated manner. Administration of doxorubicin to 4T1 tumor-bearing mice produced an eightfold increase in osteolytic lesion areas compared untreated tumor-bearing mice (P = 0.002 and an almost 50% decrease in trabecular bone volume expressed in BV/TV (P = 0.0005, both of which were rescued by anti-TGFβ antibody (1D11. Doxorubicin, which is a known inducer of oxidative stress, decreased osteoblast survival and differentiation, which was rescued by N-acetyl cysteine (NAC. Furthermore, doxorubicin treatment decreased Cu-ZnSOD (SOD1 expression and enzyme activity in vitro, and treatment with anti-TGFβ antibody was able to rescue both. In conclusion, a combination therapy using doxorubicin and anti-TGFβ antibody might be beneficial for preventing therapy-related bone loss in cancer patients.

Induction immunosuppressive therapies in renal transplantation.

Science.gov (United States)

Gabardi, Steven; Martin, Spencer T; Roberts, Keri L; Grafals, Monica

2011-02-01

Induction immunosuppressive therapies for patients undergoing renal transplantation are reviewed. The goal of induction therapy is to prevent acute rejection during the early posttransplantation period by providing a high degree of immunosuppression at the time of transplantation. Induction therapy is often considered essential to optimize outcomes, particularly in patients at high risk for poor short-term outcomes. All of the induction immunosuppressive agents currently used are biological agents and are either monoclonal (muromonab-CD3, daclizumab, basiliximab, alemtuzumab) or polyclonal (antithymocyte globulin [equine] or antithymocyte globulin [rabbit]) antibodies. Although antithymocyte globulin (rabbit) is not labeled for induction therapy, it is used for this purpose more than any other agent. Basiliximab is not considered as potent an immunosuppressive agent but has a much more favorable adverse-effect profile compared with antithymocyte globulin (rabbit) and is most commonly used in patients at low risk for acute rejection. Rituximab is being studied for use as induction therapy but to date has not demonstrated any significant benefits over placebo. While head-to-head data are available comparing most induction agents, the final decision on the most appropriate induction therapy for a transplant recipient is highly dependent on preexisting medical conditions, donor characteristics, and the maintenance immunosuppressive regimen to be used. No standard induction immunosuppressive regimen exists for patients undergoing renal transplantation. Antithymocyte globulin (rabbit) is the most commonly used agent, whereas basiliximab appears safer. The choice of regimen depends on the preferences of clinicians and institutions.

A Philosophical Treatise of Universal Induction

Directory of Open Access Journals (Sweden)

Samuel Rathmanner

2011-06-01

Full Text Available Understanding inductive reasoning is a problem that has engaged mankind for thousands of years. This problem is relevant to a wide range of fields and is integral to the philosophy of science. It has been tackled by many great minds ranging from philosophers to scientists to mathematicians, and more recently computer scientists. In this article we argue the case for Solomonoff Induction, a formal inductive framework which combines algorithmic information theory with the Bayesian framework. Although it achieves excellent theoretical results and is based on solid philosophical foundations, the requisite technical knowledge necessary for understanding this framework has caused it to remain largely unknown and unappreciated in the wider scientific community. The main contribution of this article is to convey Solomonoff induction and its related concepts in a generally accessible form with the aim of bridging this current technical gap. In the process we examine the major historical contributions that have led to the formulation of Solomonoff Induction as well as criticisms of Solomonoff and induction in general. In particular we examine how Solomonoff induction addresses many issues that have plagued other inductive systems, such as the black ravens paradox and the confirmation problem, and compare this approach with other recent approaches.

Review of induction LINACS

International Nuclear Information System (INIS)

Faltens, A.; Keefe, D.

1981-10-01

There has been a recent upsurge of activity in the field of induction linacs, with several new machines becoming operational and others in the design stages. The performance levels of electron machines have reached 10's of kiloamps of current and will soon reach 10's of MeV's of energy. Acceleration of ion current has been demonstrated, and the study of a 10 GeV heavy ion induction linac for ICF continues. The operating principles of induction linacs are reviewed with the emphasis on design choices which are important for increasing the maximum beam currents

Properties of inductive reasoning.

Science.gov (United States)

Heit, E

2000-12-01

This paper reviews the main psychological phenomena of inductive reasoning, covering 25 years of experimental and model-based research, in particular addressing four questions. First, what makes a case or event generalizable to other cases? Second, what makes a set of cases generalizable? Third, what makes a property or predicate projectable? Fourth, how do psychological models of induction address these results? The key results in inductive reasoning are outlined, and several recent models, including a new Bayesian account, are evaluated with respect to these results. In addition, future directions for experimental and model-based work are proposed.

Review of induction linacs

International Nuclear Information System (INIS)

Faltens, A.; Keefe, D.

1982-01-01

There has been a recent upsurge of activity in the field of induction linacs, with several new machines becoming operational and others in the design stages. The performance levels of electron machines have reached 10's of kiloamps of current and will soon reach 10's of MeV's of energy. Acceleration of several kiloamps of ion current has been demonstrated, and the study of a 10 GeV heavy ion induction linac for ICF continues. The operating principles of induction linacs are reviewed with the emphasis on design choices which are important for increasing the maximum beam currents

Inhibitory and inductive effects of Phikud Navakot extract on human cytochrome P450.

Science.gov (United States)

Chiangsom, Abhiruj; Lawanprasert, Somsong; Oda, Shingo; Kulthong, Kornphimol; Luechapudiporn, Rataya; Yokoi, Tsuyoshi; Maniratanachote, Rawiwan

2016-06-01

Effects of the hydroethanolic extract of Phikud Navakot (PN), a Thai traditional remedy, on human cytochrome P450s (CYPs) were investigated in vitro. Selective substrates of CYPs were used to investigate the effects and kinetics of PN on CYP inhibition using human liver microsomes. Primary human hepatocytes were used to assess the inductive effects of PN on CYP enzyme activities and protein expressions. The results showed that PN inhibited the activities of CYP1A2, CYP2C9, CYP2D6, and CYP3A4 with half maximal inhibitory concentration (IC50) values of 13, 62, 67, and 88 μg/mL, respectively. Meanwhile, it had no effect on the activities of CYP2C19 and CYP2E1 (IC50 > 1 mg/mL). PN exhibited competitive inhibition of CYP1A2 (Ki = 34 μg/mL), mixed type inhibition of CYP2C9 and CYP2D6 (Ki = 80 and 12 μg/mL, respectively), and uncompetitive inhibition of CYP3A4 (Ki = 150 μg/mL). PN did not have an inductive effect on CYP1A2, CYP2C9, CYP2C19 and CYP3A4 in primary human hepatocytes, which is an advantageous characteristic of the extract. However the extract may cause herb-drug interactions via inhibition of CYP1A2, CYP2C9, CYP2D6 and CYP3A4, and precautions should be taken when PN is coadministered with drugs that are metabolized by these CYP enzymes. Copyright © 2016 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2004-10-01

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 of action underlying these sex differences. This review examines the preclinical literature on sex differences and ovarian hormonal influences on drug self-administration in animals. It summarizes the findings on the effects of these variables during different phases of drug addiction. Possible differences in the mechanisms of action of drugs of abuse due to interactions with sex differences or ovarian hormonal factors are considered. The animal literature on sex differences in drug abuse treatment effectiveness is also discussed.

Induction of 9-cis-epoxycarotenoid dioxygenase in Arabidopsis thaliana seeds enhances seed dormancy.

Science.gov (United States)

Martínez-Andújar, Cristina; Ordiz, M Isabel; Huang, Zhonglian; Nonogaki, Mariko; Beachy, Roger N; Nonogaki, Hiroyuki

2011-10-11

Full understanding of mechanisms that control seed dormancy and germination remains elusive. Whereas it has been proposed that translational control plays a predominant role in germination, other studies suggest the importance of specific gene expression patterns in imbibed seeds. Transgenic plants were developed to permit conditional expression of a gene encoding 9-cis-epoxycarotenoid dioxygenase 6 (NCED6), a rate-limiting enzyme in abscisic acid (ABA) biosynthesis, using the ecdysone receptor-based plant gene switch system and the ligand methoxyfenozide. Induction of NCED6 during imbibition increased ABA levels more than 20-fold and was sufficient to prevent seed germination. Germination suppression was prevented by fluridone, an inhibitor of ABA biosynthesis. In another study, induction of the NCED6 gene in transgenic seeds of nondormant mutants tt3 and tt4 reestablished seed dormancy. Furthermore, inducing expression of NCED6 during seed development suppressed vivipary, precocious germination of developing seeds. These results indicate that expression of a hormone metabolism gene in seeds can be a sole determinant of dormancy. This study opens the possibility of developing a robust technology to suppress or promote seed germination through engineering pathways of hormone metabolism.

Bioengineered Temporomandibular Joint Disk Implants: Study Protocol for a Two-Phase Exploratory Randomized Preclinical Pilot Trial in 18 Black Merino Sheep (TEMPOJIMS)

Science.gov (United States)

Monje, Florencio Gil; González-García, Raúl; Little, Christopher B; Mónico, Lisete; Pinho, Mário; Santos, Fábio Abade; Carrapiço, Belmira; Gonçalves, Sandra Cavaco; Morouço, Pedro; Alves, Nuno; Moura, Carla; Wang, Yadong; Jeffries, Eric; Gao, Jin; Sousa, Rita; Neto, Lia Lucas; Caldeira, Daniel; Salvado, Francisco

2017-01-01

Background Preclinical trials are essential to test efficacious options to substitute the temporomandibular joint (TMJ) disk. The contemporary absence of an ideal treatment for patients with severe TMJ disorders can be related to difficulties concerning the appropriate study design to conduct preclinical trials in the TMJ field. These difficulties can be associated with the use of heterogeneous animal models, the use of the contralateral TMJ as control, the absence of rigorous randomized controlled preclinical trials with blinded outcomes assessors, and difficulties involving multidisciplinary teams. Objective This study aims to develop a new, reproducible, and effective study design for preclinical research in the TMJ domain, obtaining rigorous data related to (1) identify the impact of bilateral discectomy in black Merino sheep, (2) identify the impact of bilateral discopexy in black Merino sheep, and (3) identify the impact of three different bioengineering TMJ discs in black Merino sheep. Methods A two-phase exploratory randomized controlled preclinical trial with blinded outcomes is proposed. In the first phase, nine sheep are randomized into three different surgical bilateral procedures: bilateral discectomy, bilateral discopexy, and sham surgery. In the second phase, nine sheep are randomized to bilaterally test three different TMJ bioengineering disk implants. The primary outcome is the histological gradation of TMJ. Secondary outcomes are imaging changes, absolute masticatory time, ruminant time per cycle, ruminant kinetics, ruminant area, and sheep weight. Results Previous preclinical studies in this field have used the contralateral unoperated side as a control, different animal models ranging from mice to a canine model, with nonrandomized, nonblinded and uncontrolled study designs and limited outcomes measures. The main goal of this exploratory preclinical protocol is to set a new standard for future preclinical trials in oromaxillofacial surgery

Immobilized enzymes: understanding enzyme - surface interactions at the molecular level.

Science.gov (United States)

Hoarau, Marie; Badieyan, Somayesadat; Marsh, E Neil G

2017-11-22

Enzymes immobilized on solid supports have important and industrial and medical applications. However, their uses are limited by the significant reductions in activity and stability that often accompany the immobilization process. Here we review recent advances in our understanding of the molecular level interactions between proteins and supporting surfaces that contribute to changes in stability and activity. This understanding has been facilitated by the application of various surface-sensitive spectroscopic techniques that allow the structure and orientation of enzymes at the solid/liquid interface to be probed, often with monolayer sensitivity. An appreciation of the molecular interactions between enzyme and surface support has allowed the surface chemistry and method of enzyme attachement to be fine-tuned such that activity and stability can be greatly enhanced. These advances suggest that a much wider variety of enzymes may eventually be amenable to immobilization as green catalysts.

Induction generator-induction motor wind-powered pumping system

Energy Technology Data Exchange (ETDEWEB)

Miranda, M.S.; Lyra, R.O.C.; Silva, S.R. [CPDEE - UFMG, Belo Horizonte (Brazil)

1997-12-31

The energy storage matter plays an important role in wind-electric conversion systems for isolated applications. Having that in mind, two different approaches can be basically considered: either the immediate conversion of the generated electric energy, as in a water pumping system or electric energy storage for later use, as in a battery charging system. Due to some features such as no need of an external reactive power source and, sometimes, a gearbox, permanent-magnet synchronous generators have been broadly used in low rated power isolated systems. Despite that, system performance can be affected when the generator is feeding an inductive load (e.g., an induction motor) under variable-speed-variable-frequency operational conditions. Since there is no effective flux control, motor overload may occur at high wind speeds. Thus, good system performance can be obtained through additional control devices which may increase system cost. Although being rugged and cheap, induction machines always work as a reactive power drain; therefore, they demand an external reactive power source. Considering that, reactive static compensators appear as an attractive alternative to the cost x performance problem. In addition to that, different control strategies can be used so that system performance can be improved.

Two-Phase Induction Motor Drives

Directory of Open Access Journals (Sweden)

Gholam Reza Arab Markadeh

2010-10-01

Full Text Available The lack of variable-speed drives for two (single induction motor is a reality. This article attempts mainly to investigate the reasons for this lack of variable – speed drives. This paper deals with literature survey of various existing converter topologies, which have been proposed for adjustable speed single phase induction motor drives. Various converter topologies have been compared in this paper. Among these converter topologies, the adjustable frequency PWM inverter is the best choice for single-phase induction motor drives. However, adjustable-frequency drives have not been widely used with single-phase Induction motors. The open-loop constant V/F control law cannot be used with the single-phase induction motor drives as it is used with three phase motors. The variation of the operating frequency at lower speed range with constant load torque causes variation in motor's slip. A constant V/F control is suitable only over the upper speed range.

CFOA-Based Lossless and Lossy Inductance Simulators

Directory of Open Access Journals (Sweden)

F. Kaçar

2011-09-01

Full Text Available Inductance simulator is a useful component in the circuit synthesis theory especially for analog signal processing applications such as filter, chaotic oscillator design, analog phase shifters and cancellation of parasitic element. In this study, new four inductance simulator topologies employing a single current feedback operational amplifier are presented. The presented topologies require few passive components. The first topology is intended for negative inductance simulation, the second topology is for lossy series inductance, the third one is for lossy parallel inductance and the fourth topology is for negative parallel (-R (-L (-C simulation. The performance of the proposed CFOA based inductance simulators is demonstrated on both a second-order low-pass filter and inductance cancellation circuit. PSPICE simulations are given to verify the theoretical analysis.

Induction sensor for measuring the accelerating voltage in an iron-free induction accelerator

International Nuclear Information System (INIS)

Bol'nykh, N.S.; Il'in, Yu.M.; Kostyushok, A.A.; Suvorov, V.A.

1987-01-01

An inductive sensor is described for measuring the amplitude and form of the accelerating-voltage pulse in the storage coils in a radial iron-free linear induction accelerator. The sensor does not respond to interference from external fields and does not require adjustment after calibration

Expanding the Halohydrin Dehalogenase Enzyme Family: Identification of Novel Enzymes by Database Mining.

Science.gov (United States)

Schallmey, Marcus; Koopmeiners, Julia; Wells, Elizabeth; Wardenga, Rainer; Schallmey, Anett

2014-12-01

Halohydrin dehalogenases are very rare enzymes that are naturally involved in the mineralization of halogenated xenobiotics. Due to their catalytic potential and promiscuity, many biocatalytic reactions have been described that have led to several interesting and industrially important applications. Nevertheless, only a few of these enzymes have been made available through recombinant techniques; hence, it is of general interest to expand the repertoire of these enzymes so as to enable novel biocatalytic applications. After the identification of specific sequence motifs, 37 novel enzyme sequences were readily identified in public sequence databases. All enzymes that could be heterologously expressed also catalyzed typical halohydrin dehalogenase reactions. Phylogenetic inference for enzymes of the halohydrin dehalogenase enzyme family confirmed that all enzymes form a distinct monophyletic clade within the short-chain dehydrogenase/reductase superfamily. In addition, the majority of novel enzymes are substantially different from previously known phylogenetic subtypes. Consequently, four additional phylogenetic subtypes were defined, greatly expanding the halohydrin dehalogenase enzyme family. We show that the enormous wealth of environmental and genome sequences present in public databases can be tapped for in silico identification of very rare but biotechnologically important biocatalysts. Our findings help to readily identify halohydrin dehalogenases in ever-growing sequence databases and, as a consequence, make even more members of this interesting enzyme family available to the scientific and industrial community. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

The induction on a continuous variable

International Nuclear Information System (INIS)

Zhang Jingzhong.

1989-06-01

Mathematical induction is a useful tool. But it could be used to prove only the proposition with form P(n) for the natural number n. Could the natural number n be replaced by a continuous variable x? Yes, and then we have the continuous induction. The continuous induction is very easy to grasp by the students who have learned mathematical induction. And it can be used to prove many basic propositions in the elementary calculus. (author)

Recommendations concerning the new U.S. National Institutes of Health initiative to balance the sex of cells and animals in preclinical research.

Science.gov (United States)

Sandberg, Kathryn; Umans, Jason G

2015-05-01

The U.S. National Institutes of Health (NIH) announced last May that steps will be taken to address the over-reliance on male cells and animals in preclinical research. To further address this announcement, in September 2014, scientists with varying perspectives came together at Georgetown University to discuss the following questions. (1) What metrics should the NIH use to assess tangible progress on policy changes designed to address the over-reliance on male cells and animals in preclinical research? (2) How effective can education be in reducing the over-reliance on male cells and animals in preclinical research and what educational initiatives sponsored by the NIH would most likely effect change? (3) What criteria should the NIH use to determine rigorously defined exceptions to the future proposal requirement of a balance of male and female cells and animals in preclinical studies? (4) What additional strategies in addition to proposal requirements should NIH use to reduce the overreliance of male cells and animals in preclinical research? The resulting consensus presented herein includes input from researchers not only from diverse disciplines of basic and translational science including biology, cell and molecular biology, biochemistry, physiology, pharmacology, neuroscience, cardiology, endocrinology, nephrology, psychiatry, and obstetrics and gynecology, but also from recognized experts in publishing, industry, advocacy, science policy, clinical medicine, and population health. We offer our recommendations to aid the NIH as it selects, implements, monitors, and optimizes strategies to correct the over-reliance on male cells and animals in preclinical research. © FASEB.

Metagenomics as a Tool for Enzyme Discovery: Hydrolytic Enzymes from Marine-Related Metagenomes.

Science.gov (United States)

Popovic, Ana; Tchigvintsev, Anatoly; Tran, Hai; Chernikova, Tatyana N; Golyshina, Olga V; Yakimov, Michail M; Golyshin, Peter N; Yakunin, Alexander F

2015-01-01

This chapter discusses metagenomics and its application for enzyme discovery, with a focus on hydrolytic enzymes from marine metagenomic libraries. With less than one percent of culturable microorganisms in the environment, metagenomics, or the collective study of community genetics, has opened up a rich pool of uncharacterized metabolic pathways, enzymes, and adaptations. This great untapped pool of genes provides the particularly exciting potential to mine for new biochemical activities or novel enzymes with activities tailored to peculiar sets of environmental conditions. Metagenomes also represent a huge reservoir of novel enzymes for applications in biocatalysis, biofuels, and bioremediation. Here we present the results of enzyme discovery for four enzyme activities, of particular industrial or environmental interest, including esterase/lipase, glycosyl hydrolase, protease and dehalogenase.

Phenobarbital induction and chemical synergism demonstrate the role of UDP-glucuronosyltransferases in detoxification of naphthalophos by Haemonchus contortus larvae.

Science.gov (United States)

Kotze, Andrew C; Ruffell, Angela P; Ingham, Aaron B

2014-12-01

We used an enzyme induction approach to study the role of detoxification enzymes in the interaction of the anthelmintic compound naphthalophos with Haemonchus contortus larvae. Larvae were treated with the barbiturate phenobarbital, which is known to induce the activity of a number of detoxification enzymes in mammals and insects, including cytochromes P450 (CYPs), UDP-glucuronosyltransferases (UDPGTs), and glutathione (GSH) S-transferases (GSTs). Cotreatment of larvae with phenobarbital and naphthalophos resulted in a significant increase in the naphthalophos 50% inhibitory concentration (IC50) compared to treatment of larvae with the anthelmintic alone (up to a 28-fold increase). The phenobarbital-induced drug tolerance was reversed by cotreatment with the UDPGT inhibitors 5-nitrouracil, 4,6-dihydroxy-5-nitropyrimidine, probenecid, and sulfinpyrazone. Isobologram analysis of the interaction of 5-nitrouracil with naphthalophos in phenobarbital-treated larvae clearly showed the presence of strong synergism. The UDPGT inhibitors 5-nitrouracil, 4,6-dihydroxy-5-nitropyrimidine, and probenecid also showed synergistic effects with non-phenobarbital-treated worms (synergism ratio up to 3.2-fold). This study indicates that H. contortus larvae possess one or more UDPGT enzymes able to detoxify naphthalophos. In highlighting the protective role of this enzyme group, this study reveals the potential for UDPGT enzymes to act as a resistance mechanism that may develop under drug selection pressure in field isolates of this species. In addition, the data indicate the potential for a chemotherapeutic approach utilizing inhibitors of UDPGT enzymes as synergists to increase the activity of naphthalophos against parasitic worms and to combat detoxification-mediated drug resistance if it arises in the field. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Development of induction cells at CAEP

International Nuclear Information System (INIS)

Wang Huacen; Zhang Kaizhi; Cheng Nian'an; Zhang Wenwei; Lai Qinggui; Wen Long; Zhang Linwen; Deng Jianjun; Ding Bonan

2002-01-01

The effects to develop induction cells for induction linac and radiography at CAEP are introduced and reviewed in this paper. During the past two decades, several kinds of cells have been designed and tested, and some of them have been used for construction of induction linac, such as Dragon-1 and 12 MeV, and a Synthetic Test Stand (STS) for comprehensive linac technology study. The structure, test results and performance in the induction linac of these cells are given

Rapid Induction of Aldosterone Synthesis in Cultured Neonatal Rat Cardiomyocytes under High Glucose Conditions

Directory of Open Access Journals (Sweden)

Masami Fujisaki

2013-01-01

Full Text Available In addition to classical adrenal cortical biosynthetic pathway, there is increasing evidence that aldosterone is produced in extra-adrenal tissues. Although we previously reported aldosterone production in the heart, the concept of cardiac aldosterone synthesis remains controversial. This is partly due to lack of established experimental models representing aldosterone synthase (CYP11B2 expression in robustly reproducible fashion. We herein investigated suitable conditions in neonatal rat cardiomyocytes (NRCMs culture system producing CYP11B2 with considerable efficacy. NRCMs were cultured with various glucose doses for 2–24 hours. CYP11B2 mRNA expression and aldosterone concentrations secreted from NRCMs were determined using real-time PCR and enzyme immunoassay, respectively. We found that suitable conditions for CYP11B2 induction included four-hour incubation with high glucose conditions. Under these particular conditions, CYP11B2 expression, in accordance with aldosterone secretion, was significantly increased compared to those observed in the cells cultured under standard-glucose condition. Angiotensin II receptor blocker partially inhibited this CYP11B2 induction, suggesting that there is local renin-angiotensin-aldosterone system activation under high glucose conditions. The suitable conditions for CYP11B2 induction in NRCMs culture system are now clarified: high-glucose conditions with relatively brief period of culture promote CYP11B2 expression in cardiomyocytes. The current system will help to accelerate further progress in research on cardiac tissue aldosterone synthesis.

Enzymes and Enzyme Activity Encoded by Nonenveloped Viruses.

Science.gov (United States)

Azad, Kimi; Banerjee, Manidipa; Johnson, John E

2017-09-29

Viruses are obligate intracellular parasites that rely on host cell machineries for their replication and survival. Although viruses tend to make optimal use of the host cell protein repertoire, they need to encode essential enzymatic or effector functions that may not be available or accessible in the host cellular milieu. The enzymes encoded by nonenveloped viruses-a group of viruses that lack any lipid coating or envelope-play vital roles in all the stages of the viral life cycle. This review summarizes the structural, biochemical, and mechanistic information available for several classes of enzymes and autocatalytic activity encoded by nonenveloped viruses. Advances in research and development of antiviral inhibitors targeting specific viral enzymes are also highlighted.

Linear induction accelerator

Science.gov (United States)

Buttram, M.T.; Ginn, J.W.

1988-06-21

A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities. 4 figs.

Pre-clinical evaluation of extracts and essential oils from betel-like ...

African Journals Online (AJOL)

The extracts and oils were preclinically studied based on cyto - and genotoxicity using microculture tetrazolium (MTT) and comet assays. Results: The crude extracts showed an IC50 in leukocytes and HeLa cells of 58.59 -97.31 mg/ml and 34.91-101.79 mg/ml, the LD50 is higher than 5000 mg/kg. With lower values than the ...

Model of Transient Process Where Three-Phase Transducer Feeds Induction Motor Equivalent as a Variable Active-Inductive Load

Directory of Open Access Journals (Sweden)

Nenad Marković

2016-01-01

Full Text Available The paper presents a new approach in the analysis of a transient state in a system where the feeding source is a transducer-IGBT inverter and load is introduced through the induction motor with its R-L parameters. Induction motors with different parameters of powers and power factors are tested. MATLAB simulation of the three-phase inverter that feeds the induction machine has replaced the missing lab equipment with which mathematical model of this system was verified. According to the selected parameters of the inverter and induction machine and through the simulation in the MATLAB program, the results are obtained in the form of diagrams that verify the model of a transient state of the induction machine operation when it operates as a motor which is presented as a variable R-L load. The transient process of the system three-phase bridge inverter whose active-inductive load is the induction machine in the conditions of the change of the load parameters is analyzed. The model of the transient process in the system formed by the inverter in PWM (Pulse Width Modulation converter and induction machine is developed in the time domain and phase coordinates.

Induction of mutation in Aspergillus niger for conversion of cellulose into glucose

Energy Technology Data Exchange (ETDEWEB)

Helmi, S.; Khalil, A.E.; Tahoun, M.K.; Khairy, A.H. [Univ. of Alexandria Research Centre, Alexandria (Egypt)

1991-12-31

Plant wastes are very important part of biomass used and investigated for energy, chemical, and fuel production. Cellulose is the major renewable form of carbohydrate in the world, about 10{sup 11} tons of which is synthesized annually. For general use, it must be hydrolyzed first, either chemically or by cellulases derived from a few specialized microorganisms. Enzymes are acceptable environmentally but expensive to produce. Certainly, induction of mutations and selection of high cellulose microbial strains with significant adaptability to degrade cellulose to glucose is promising solutions. Induction of mutations in other fungi and Aspergillus sp. rather than Aspergillus niger was reported. Aspergillus ustus and Trichoderma harzianum were induced by gamma irradiation indicating mutants that excrete higher cellulose yields, particularly exocellobiohydrolase (Avicelase) than their respective wild types. Mutants from the celluiolytic fungus Penicillium pinophilum were induced by chemical and UV-irradiation. Enhancing the production of endo-1,4-{Beta}-D-glucanase (CMCase) and particularly {Beta}-glucosidase was obtained by gamma irradiation of Altemaria alternate. To overcome the lower activity of {beta}-glucosidase in certain fungi species rather than A. niger, mixed cultures of different species were tried. Thus, Aspergillus phonicis with Trichoderma reesei Rut 30, produced a cellulose complex that improved activity twofold over cellulose from Trichoderma alone.

Phenotypical difference in deamination of cytarabine is not evident in induction therapy for acute myeloid leukemia

DEFF Research Database (Denmark)

Krogh-Madsen, Mikkel; Hansen, Steen Honore'; Jensen, Morten Krogh

2013-01-01

Objective To investigate the uracil arabinoside/cytarabine (Ara-U/Ara-C) ratios with the lower dose in adult acute myeloid leukaemia (AML) induction therapy (100 mg/m2 Ara-C) where no enzyme saturation is expected. Methods A precise and robust high-performance liquid chromatography (HPLC) method...... for simultaneous determination of Ara-C and its main inactive metabolite Ara-U in human plasma was developed and validated. Nineteen patients with acute myeloid leukaemia were treated with Ara-C in a dose of 100 mg/m2 together with daunorubicin and etoposide. Plasma concentrations were used to construct...

Pre-clinical research in small animals using radiotherapy technology. A bidirectional translational approach

International Nuclear Information System (INIS)

Tillner, Falk; Buetof, Rebecca; Krause, Mechthild; Enghardt, Wolfgang; Helmholtz-Zentrum Dresden-Rossendorf, Dresden; Technische Univ. Dresden; Helmholtz-Zentrum Dresden-Rossendorf, Dresden

2014-01-01

For translational cancer research, pre-clinical in-vivo studies using small animals have become indispensable in bridging the gap between in-vitro cell experiments and clinical implementation. When setting up such small animal experiments, various biological, technical and methodical aspects have to be considered. In this work we present a comprehensive topical review based on relevant publications on irradiation techniques used for pre-clinical cancer research in mice and rats. Clinical radiotherapy treatment devices for the application of external beam radiotherapy and brachytherapy as well as dedicated research irradiation devices are feasible for small animal irradiation depending on the animal model and the experimental goals. In this work, appropriate solutions for the technological transfer of human radiation oncology to small animal radiation research are summarised. Additionally, important information concerning the experimental design is provided such that reliable and clinically relevant results can be attained.

Thymoquinone as a Potential Adjuvant Therapy for Cancer Treatment: Evidence from Preclinical Studies

Directory of Open Access Journals (Sweden)

A.G.M. Mostofa

2017-06-01

Full Text Available Thymoquinone (TQ, the main bioactive component of Nigella sativa, has been found to exhibit anticancer effects in numerous preclinical studies. Due to its multitargeting nature, TQ interferes in a wide range of tumorigenic processes and counteracts carcinogenesis, malignant growth, invasion, migration, and angiogenesis. Moreover, TQ can specifically sensitize tumor cells toward conventional cancer treatments (e.g., radiotherapy, chemotherapy, and immunotherapy and simultaneously minimize therapy-associated toxic effects in normal cells. In this review, we summarized the adjuvant potential of TQ as observed in various in vitro and in vivo animal models and discussed the pharmacological properties of TQ to rationalize its supplementary role in potentiating the efficacy of standard therapeutic modalities namely surgery, radiotherapy, chemotherapy, and immunotherapy. Altogether, we suggest further comprehensive evaluation of TQ in preclinical and clinical levels to delineate its implied utility as a novel complementary adjuvant therapy for cancer treatment.

Tendinopathies and platelet-rich plasma (PRP: from pre-clinical experiments to therapeutic use

Directory of Open Access Journals (Sweden)

Kaux JF

2015-05-01

Full Text Available Objectives: The restorative properties of platelets, through the local release of growth factors, are used in various medical areas. This article reviews fundamental and clinical research relating to platelet-rich plasma applied to tendinous lesions. Materials and method: Articles in French and English, published between 1 January 2012 and 31 December 2014. dealing with PRP and tendons were searched for using the Medline and Scopus data bases. Results: Forty-seven articles were identified which addressed pre-clinical and clinical studies: 27 relating to in vitro and in vivo animal studies and 20 relating to human studies. Of these, five addressed lateral epicondylitis, two addressed rotator cuff tendinopathies, ten dealt with patellar tendinopathies and three looked at Achilles tendinopathies. Conclusions: The majority of pre-clinical studies show that PRP stimulates the tendon's healing process. However, clinical series remain more controversial and level 1, controlled, randomised studies are still needed.

A student-initiated and student-facilitated international health elective for preclinical medical students.

Science.gov (United States)

Vora, Nirali; Chang, Mina; Pandya, Hemang; Hasham, Aliya; Lazarus, Cathy

2010-02-15

Global health education is becoming more important for developing well-rounded physicians and may encourage students toward a career in primary care. Many medical schools, however, lack adequate and structured opportunities for students beginning the curriculum. Second-year medical students initiated, designed, and facilitated a pass-fail international health elective, providing a curricular framework for preclinical medical students wishing to gain exposure to the clinical and cultural practices of a developing country. All course participants (N=30) completed a post-travel questionnaire within one week of sharing their experiences. Screening reflection essays for common themes that fulfill university core competencies yielded specific global health learning outcomes, including analysis of health care determinants. Medical students successfully implemented a sustainable global health curriculum for preclinical student peers. Financial constraints, language, and organizational burdens limit student participation. In future, long-term studies should analyze career impact and benefits to the host country.

Pre-clinical research in small animals using radiotherapy technology. A bidirectional translational approach

Energy Technology Data Exchange (ETDEWEB)

Tillner, Falk; Buetof, Rebecca [Technische Univ. Dresden (Germany). OncoRay - National Center for Radiation Research in Oncology; Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Technische Univ. Dresden (Germany). Dept. of Radiation Oncology; Thute, Prasad [Technische Univ. Dresden (Germany). OncoRay - National Center for Radiation Research in Oncology; Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Krause, Mechthild [Technische Univ. Dresden (Germany). OncoRay - National Center for Radiation Research in Oncology; Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Technische Univ. Dresden (Germany). Dept. of Radiation Oncology; German Cancer Consortium (DKTK), Dresden (Germany); German Cancer Research Center (DKFZ), Heidelberg (Germany); Enghardt, Wolfgang [Technische Univ. Dresden (Germany). OncoRay - National Center for Radiation Research in Oncology; Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Technische Univ. Dresden (Germany). Dept. of Radiation Oncology; Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany). Inst. of Radiooncology

2014-07-01

For translational cancer research, pre-clinical in-vivo studies using small animals have become indispensable in bridging the gap between in-vitro cell experiments and clinical implementation. When setting up such small animal experiments, various biological, technical and methodical aspects have to be considered. In this work we present a comprehensive topical review based on relevant publications on irradiation techniques used for pre-clinical cancer research in mice and rats. Clinical radiotherapy treatment devices for the application of external beam radiotherapy and brachytherapy as well as dedicated research irradiation devices are feasible for small animal irradiation depending on the animal model and the experimental goals. In this work, appropriate solutions for the technological transfer of human radiation oncology to small animal radiation research are summarised. Additionally, important information concerning the experimental design is provided such that reliable and clinically relevant results can be attained.

Concise Review: Mesenchymal Stem (Stromal) Cells: Biology and Preclinical Evidence for Therapeutic Potential for Organ Dysfunction Following Trauma or Sepsis.

Science.gov (United States)

Matthay, Michael A; Pati, Shibani; Lee, Jae-Woo

2017-02-01

Several experimental studies have provided evidence that bone-marrow derived mesenchymal stem (stromal) cells (MSC) may be effective in treating critically ill surgical patients who develop traumatic brain injury, acute renal failure, or the acute respiratory distress syndrome. There is also preclinical evidence that MSC may be effective in treating sepsis-induced organ failure, including evidence that MSC have antimicrobial properties. This review considers preclinical studies with direct relevance to organ failure following trauma, sepsis or major infections that apply to critically ill patients. Progress has been made in understanding the mechanisms of benefit, including MSC release of paracrine factors, transfer of mitochondria, and elaboration of exosomes and microvesicles. Regardless of how well they are designed, preclinical studies have limitations in modeling the complexity of clinical syndromes, especially in patients who are critically ill. In order to facilitate translation of the preclinical studies of MSC to critically ill patients, there will need to be more standardization regarding MSC production with a focus on culture methods and cell characterization. Finally, well designed clinical trials will be needed in critically ill patient to assess safety and efficacy. Stem Cells 2017;35:316-324. © 2016 AlphaMed Press.

Strong synergistic induction of CYP1A1 expression by andrographolide plus typical CYP1A inducers in mouse hepatocytes

Energy Technology Data Exchange (ETDEWEB)

Jaruchotikamol, Atika [Department of Toxicology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Jarukamjorn, Kanokwan [Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002 (Thailand); Sirisangtrakul, Wanna [Department of Toxicology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002 (Thailand); Sakuma, Tsutomu; Kawasaki, Yuki [Department of Toxicology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Nemoto, Nobuo [Department of Toxicology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan)

2007-10-15

The effects of andrographolide, the major diterpenoid constituent of Andrographis paniculata, on the expression of cytochrome P450 superfamily 1 members, including CYP1A1, CYP1A2, and CYP1B1, as well as on aryl hydrocarbon receptor (AhR) expression in primary cultures of mouse hepatocytes were investigated in comparison with the effects of typical CYP1A inducers, including benz[a]anthracene, {beta}-naphthoflavone, and 2,3,7,8-tetrachlorodibenzo-p-dioxin. Andrographolide significantly induced the expression of CYP1A1 and CYP1A2 mRNAs in a concentration-dependent manner, as did the typical CYP1A inducers, but did not induce that of CYP1B1 or AhR. Interestingly, andrographolide plus the typical CYP1A inducers synergistically induced CYP1A1 expression, and the synergism was blocked by an AhR antagonist, resveratrol. The CYP1A1 enzyme activity showed a similar pattern of induction. This is the first report that shows that andrographolide has a potency to induce CYP1A1 enzyme and indicates that andrographolide could be a very useful compound for investigating the regulatory mechanism of the CYP1A1 induction pathway. In addition, our findings suggest preparing advice for rational administration of A. paniculata, according to its ability to induce CYP1A1 expression.

Strong synergistic induction of CYP1A1 expression by andrographolide plus typical CYP1A inducers in mouse hepatocytes

International Nuclear Information System (INIS)

Jaruchotikamol, Atika; Jarukamjorn, Kanokwan; Sirisangtrakul, Wanna; Sakuma, Tsutomu; Kawasaki, Yuki; Nemoto, Nobuo

2007-01-01

The effects of andrographolide, the major diterpenoid constituent of Andrographis paniculata, on the expression of cytochrome P450 superfamily 1 members, including CYP1A1, CYP1A2, and CYP1B1, as well as on aryl hydrocarbon receptor (AhR) expression in primary cultures of mouse hepatocytes were investigated in comparison with the effects of typical CYP1A inducers, including benz[a]anthracene, β-naphthoflavone, and 2,3,7,8-tetrachlorodibenzo-p-dioxin. Andrographolide significantly induced the expression of CYP1A1 and CYP1A2 mRNAs in a concentration-dependent manner, as did the typical CYP1A inducers, but did not induce that of CYP1B1 or AhR. Interestingly, andrographolide plus the typical CYP1A inducers synergistically induced CYP1A1 expression, and the synergism was blocked by an AhR antagonist, resveratrol. The CYP1A1 enzyme activity showed a similar pattern of induction. This is the first report that shows that andrographolide has a potency to induce CYP1A1 enzyme and indicates that andrographolide could be a very useful compound for investigating the regulatory mechanism of the CYP1A1 induction pathway. In addition, our findings suggest preparing advice for rational administration of A. paniculata, according to its ability to induce CYP1A1 expression

Role of brain cytochrome P450 mono-oxygenases in bilirubin oxidation-specific induction and activity.

Science.gov (United States)

Gambaro, Sabrina E; Robert, Maria C; Tiribelli, Claudio; Gazzin, Silvia

2016-02-01

In the Crigler-Najjar type I syndrome, the genetic absence of efficient hepatic glucuronidation of unconjugated bilirubin (UCB) by the uridine 5'-diphospho-glucuronosyltransferase1A1 (UGT1A1) enzyme produces the rise of UCB level in blood. Its entry to central nervous system could generate toxicity and neurological damage, and even death. In the past years, a compensatory mechanism to liver glucuronidation has been indicated in the hepatic cytochromes P450 enzymes (Cyps) which are able to oxidize bilirubin. Cyps are expressed also in the central nervous system, the target of bilirubin toxicity, thus making them theoretically important to confer a protective activity toward bilirubin accumulation and neurotoxicity. We therefore investigated the functional induction (mRNA, EROD/MROD) and the ability to oxidize bilirubin of Cyp1A1, 1A2, and 2A3 in primary astrocytes cultures obtained from two rat brain region (cortex: Cx and cerebellum: Cll). We observed that Cyp1A1 was the Cyp isoform more easily induced by beta-naphtoflavone (βNF) in both Cx and Cll astrocytes, but oxidized bilirubin only after uncoupling by 3, 4,3',4'-tetrachlorobiphenyl (TCB). On the contrary, Cyp1A2 was the most active Cyp in bilirubin clearance without uncoupling, but its induction was confined only in Cx cells. Brain Cyp2A3 was not inducible. In conclusion, the exposure of astrocytes to βNF plus TCB significantly enhanced Cyp1A1 mediating bilirubin clearance, improving cell viability in both regions. These results may be a relevant groundwork for the manipulation of brain Cyps as a therapeutic approach in reducing bilirubin-induced neurological damage.

Effect of inter-tissue inductive coupling on multi-frequency imaging of intracranial hemorrhage by magnetic induction tomography

Science.gov (United States)

Xiao, Zhili; Tan, Chao; Dong, Feng

2017-08-01

Magnetic induction tomography (MIT) is a promising technique for continuous monitoring of intracranial hemorrhage due to its contactless nature, low cost and capacity to penetrate the high-resistivity skull. The inter-tissue inductive coupling increases with frequency, which may lead to errors in multi-frequency imaging at high frequency. The effect of inter-tissue inductive coupling was investigated to improve the multi-frequency imaging of hemorrhage. An analytical model of inter-tissue inductive coupling based on the equivalent circuit was established. A set of new multi-frequency decomposition equations separating the phase shift of hemorrhage from other brain tissues was derived by employing the coupling information to improve the multi-frequency imaging of intracranial hemorrhage. The decomposition error and imaging error are both decreased after considering the inter-tissue inductive coupling information. The study reveals that the introduction of inter-tissue inductive coupling can reduce the errors of multi-frequency imaging, promoting the development of intracranial hemorrhage monitoring by multi-frequency MIT.

Structured Statistical Models of Inductive Reasoning

Science.gov (United States)

Kemp, Charles; Tenenbaum, Joshua B.

2009-01-01

Everyday inductive inferences are often guided by rich background knowledge. Formal models of induction should aim to incorporate this knowledge and should explain how different kinds of knowledge lead to the distinctive patterns of reasoning found in different inductive contexts. This article presents a Bayesian framework that attempts to meet…

Perceptions of Teaching Methods for Preclinical Oral Surgery: A Comparison with Learning Styles

Science.gov (United States)

Omar, Esam

2017-01-01

Purpose: Dental extraction is a routine part of clinical dental practice. For this reason, understanding the way how students’ extraction knowledge and skills development are important. Problem Statement and Objectives: To date, there is no accredited statement about the most effective method for the teaching of exodontia to dental students. Students have different abilities and preferences regarding how they learn and process information. This is defined as learning style. In this study, the effectiveness of active learning in the teaching of preclinical oral surgery was examined. The personality type of the groups involved in this study was determined, and the possible effect of personality type on learning style was investigated. Method: This study was undertaken over five years from 2011 to 2015. The sample consisted of 115 students and eight staff members. Questionnaires were submitted by 68 students and all eight staff members involved. Three measures were used in the study: The Index of Learning Styles (Felder and Soloman, 1991), the Myers-Briggs Type Indicator (MBTI), and the styles of learning typology (Grasha and Hruska-Riechmann). Results and Discussion: Findings indicated that demonstration and minimal clinical exposure give students personal validation. Frequent feedback on their work is strongly indicated to build the cognitive, psychomotor, and interpersonal skills needed from preclinical oral surgery courses. Conclusion: Small group cooperative active learning in the form of demonstration and minimal clinical exposure that gives frequent feedback and students’ personal validation on their work is strongly indicated to build the skills needed for preclinical oral surgery courses. PMID:28357004

Preclinical evaluation of human T lymphocytes in RAG2-/-γc-/- mice

NARCIS (Netherlands)

Rijn, R.S. van

2006-01-01

This thesis describes the development and application of a new model for the preclinical study of human T cells by transfer of huPBMCs into RAG2-/-γc-/- immunodeficient mice. The ultimate goal of treating patients with a malignancy is to eradicate the malignant cells, while keeping hold of damage to

Assessment and modeling of inductive and non-inductive scenarios for ITER

International Nuclear Information System (INIS)

Boucher, D.; Vayakis, G.; Moreau, D.

1999-01-01

This paper presents recent developments in modeling and simulations of ITER performances and scenarios. The first part presents an improved modeling of coupled divertor/main plasma operation including the simulation of the measurements involved in the control loop. The second part explores the fusion performances predicted under non-inductive operation with internal transport barrier. The final part covers a detailed scenario for non-inductive operation using a reverse shear configuration with lower hybrid and fast wave current drive. (author)

Neurosurgery Elective for Preclinical Medical Students: Early Exposure and Changing Attitudes.

Science.gov (United States)

Zuckerman, Scott L; Mistry, Akshitkumar M; Hanif, Rimal; Chambless, Lola B; Neimat, Joseph S; Wellons, John C; Mocco, J; Sills, Allen K; McGirt, Matthew J; Thompson, Reid C

2016-02-01

Exposure to surgical subspecialties is limited during the preclinical years of medical school. To offset this limitation, the authors created a neurosurgery elective for first- and second-year medical students. The objective was to provide each student with early exposure to neurosurgery by combining clinical experience with faculty discussions about the academic and personal realities of a career in neurosurgery. From 2012 to 2013, the authors offered a neurosurgery elective course to first- and second-year medical students. Each class consisted of the following: 1) peer-reviewed article analysis; 2) student presentation; 3) faculty academic lecture; 4) faculty personal lecture with question and answer period. Thirty-five students were enrolled over a 2-year period. After completing the elective, students were more likely to: consider neurosurgery as a future career (P life to be higher (P life, and family-work balance, while not altering the students' views about the difficulty of training. Adopting a neurosurgery elective geared towards preclinical medical students can significantly change attitudes about the field of neurosurgery and has potential to increase interest in pursuing a career in neurosurgery. Copyright © 2016 Elsevier Inc. All rights reserved.

Lymphoma: current status of clinical and preclinical imaging with radiolabeled antibodies

Energy Technology Data Exchange (ETDEWEB)

England, Christopher G. [University of Wisconsin School of Medicine and Public Health, Department of Medical Physics, Madison, WI (United States); Rui, Lixin [University of Wisconsin School of Medicine and Public Health, Department of Medicine, Madison, WI (United States); University of Wisconsin School of Medicine and Public Health, Carbone Cancer Center, Madison, WI (United States); Cai, Weibo [University of Wisconsin School of Medicine and Public Health, Department of Medical Physics, Madison, WI (United States); University of Wisconsin School of Medicine and Public Health, Carbone Cancer Center, Madison, WI (United States); University of Wisconsin School of Medicine and Public Health, Department of Radiology, Madison, WI (United States)

2017-03-15

Lymphoma is a complex disease that arises from cells of the immune system with an intricate pathology. While lymphoma may be classified as Hodgkin or non-Hodgkin, each type of tumor is genetically and phenotypically different and highly invasive tissue biopsies are the only method to investigate these differences. Noninvasive imaging strategies, such as immunoPET, can provide a vital insight into disease staging, monitoring treatment response in patients, and dose planning in radioimmunotherapy. ImmunoPET imaging with radiolabeled antibody-based tracers may also assist physicians in optimizing treatment strategies and enhancing patient stratification. Currently, there are two common biomarkers for molecular imaging of lymphoma, CD20 and CD30, both of which have been considered for investigation in preclinical imaging studies. In this review, we examine the current status of both preclinical and clinical imaging of lymphoma using radiolabeled antibodies. Additionally, we briefly investigate the role of radiolabeled antibodies in lymphoma therapy. As radiolabeled antibodies play critical roles in both imaging and therapy of lymphoma, the development of novel antibodies and the discovery of new biomarkers may greatly affect lymphoma imaging and therapy in the future. (orig.)

Lymphoma: current status of clinical and preclinical imaging with radiolabeled antibodies

International Nuclear Information System (INIS)

England, Christopher G.; Rui, Lixin; Cai, Weibo

2017-01-01

Lymphoma is a complex disease that arises from cells of the immune system with an intricate pathology. While lymphoma may be classified as Hodgkin or non-Hodgkin, each type of tumor is genetically and phenotypically different and highly invasive tissue biopsies are the only method to investigate these differences. Noninvasive imaging strategies, such as immunoPET, can provide a vital insight into disease staging, monitoring treatment response in patients, and dose planning in radioimmunotherapy. ImmunoPET imaging with radiolabeled antibody-based tracers may also assist physicians in optimizing treatment strategies and enhancing patient stratification. Currently, there are two common biomarkers for molecular imaging of lymphoma, CD20 and CD30, both of which have been considered for investigation in preclinical imaging studies. In this review, we examine the current status of both preclinical and clinical imaging of lymphoma using radiolabeled antibodies. Additionally, we briefly investigate the role of radiolabeled antibodies in lymphoma therapy. As radiolabeled antibodies play critical roles in both imaging and therapy of lymphoma, the development of novel antibodies and the discovery of new biomarkers may greatly affect lymphoma imaging and therapy in the future. (orig.)

The surface science of enzymes

DEFF Research Database (Denmark)

Rod, Thomas Holm; Nørskov, Jens Kehlet

2002-01-01

One of the largest challenges to science in the coming years is to find the relation between enzyme structure and function. Can we predict which reactions an enzyme catalyzes from knowledge of its structure-or from its amino acid sequence? Can we use that knowledge to modify enzyme function......? To solve these problems we must understand in some detail how enzymes interact with reactants from its surroundings. These interactions take place at the surface of the enzyme and the question of enzyme function can be viewed as the surface science of enzymes. In this article we discuss how to describe...... catalysis by enzymes, and in particular the analogies between enzyme catalyzed reactions and surface catalyzed reactions. We do this by discussing two concrete examples of reactions catalyzed both in nature (by enzymes) and in industrial reactors (by inorganic materials), and show that although analogies...

Structure of Human cGAS Reveals a Conserved Family of Second-Messenger Enzymes in Innate Immunity

Directory of Open Access Journals (Sweden)

Philip J. Kranzusch

2013-05-01

Full Text Available Innate immune recognition of foreign nucleic acids induces protective interferon responses. Detection of cytosolic DNA triggers downstream immune signaling through activation of cyclic GMP-AMP synthase (cGAS. We report here the crystal structure of human cGAS, revealing an unanticipated zinc-ribbon DNA-binding domain appended to a core enzymatic nucleotidyltransferase scaffold. The catalytic core of cGAS is structurally homologous to the RNA-sensing enzyme, 2′-5′ oligo-adenylate synthase (OAS, and divergent C-terminal domains account for specific ligand-activation requirements of each enzyme. We show that the cGAS zinc ribbon is essential for STING-dependent induction of the interferon response and that conserved amino acids displayed within the intervening loops are required for efficient cytosolic DNA recognition. These results demonstrate that cGAS and OAS define a family of innate immunity sensors and that structural divergence from a core nucleotidyltransferase enables second-messenger responses to distinct foreign nucleic acids.

PARIS reprograms glucose metabolism by HIF-1α induction in dopaminergic neurodegeneration.

Science.gov (United States)

Kang, Hojin; Jo, Areum; Kim, Hyein; Khang, Rin; Lee, Ji-Yeong; Kim, Hanna; Park, Chi-Hu; Choi, Jeong-Yun; Lee, Yunjong; Shin, Joo-Ho

2018-01-22

Our previous study found that PARIS (ZNF746) transcriptionally suppressed transketolase (TKT), a key enzyme in pentose phosphate pathway (PPP) in the substantia nigra (SN) of AAV-PARIS injected mice. In this study, we revealed that PARIS overexpression reprogrammed glucose metabolic pathway, leading to the increment of glycolytic proteins along with TKT reduction in the SN of AAV-PARIS injected mice. Knock-down of TKT in differentiated SH-SY5Y cells led to an increase of glycolytic enzymes and decrease of PPP-related enzymes whereas overexpression of TKT restored PARIS-mediated glucose metabolic shift, suggesting that glucose metabolic alteration by PARIS is TKT-dependent. Inhibition of PPP by either PARIS overexpression or TKT knock-down elevated the level of H 2 O 2 , and diminished NADPH and GSH levels, ultimately triggering the induction of HIF-1α, a master activator of glycolysis. In addition, TKT inhibition by stereotaxic injection of oxythiamine demonstrated slight decrement of dopaminergic neurons (DNs) in SN but not cortical neurons in the cortex, suggesting that TKT might be a survival factor of DNs. In differentiated SH-SY5Y, cell toxicity by GFP-PARIS was partially restored by introduction of Flag-TKT and siRNA-HIF-1α. We also observed the increase of HIF-1α and glycolytic hexokinase 2 in the SN of Parkinson's disease patients. Taken together, these results suggest that PARIS accumulation might distort the balance of glucose metabolism, providing clues for understanding mechanism underlying selective DNs death by PARIS. Copyright © 2017 Elsevier Inc. All rights reserved.

[Mood induction procedures: a critical review].

Science.gov (United States)

Gilet, A-L

2008-06-01

For a long period in the history of psychological research, emotion and cognition have been studied independently, as if one were irrelevant to the other. The renewed interest of researchers for the study of the relations between cognition and emotion has led to the development of a range of laboratory methods for inducing temporary mood states. This paper aims to review the main mood induction procedures allowing the induction of a negative mood as well as a positive mood, developed since the pioneer study of Schachter and Singer [Psychol Rev 69 (1962) 379-399] and to account for the usefulness and problems related to the use of such techniques. The first part of this paper deals with the detailed presentation of some of the most popular mood induction procedures according to their type: simple (use of only one mood induction technique) or combined (association of two or more techniques at once). The earliest of the modern techniques is the Velten Mood Induction Procedure [Behav Res Ther 6 (1968) 473-482], which involves reading aloud sixty self-referent statements progressing from relative neutral mood to negative mood or dysphoria. Some researchers have varied the procedure slightly by changing the number of the statements [Behav Res Ther 21 (1983) 233-239, Br J Clin Psychol 21 (1982) 111-117, J Pers Soc Psychol 35 (1977) 625-636]. Various other mood induction procedures have been developed including music induction [Cogn Emotion 11 (1997) 403-432, Br J Med Psychol 55 (1982) 127-138], film clip induction [J Pers Soc Psychol 20 (1971) 37-43, Cogn Emotion 7 (1993) 171-193, Rottenberg J, Ray RR, Gross JJ. Emotion elicitation using films. In: Coan JA, Allen JJB, editors. The handbook of emotion elicitation and assessment. New York: Oxford University Press, 2007], autobiographical recall [J Clin Psychol 36 (1980) 215-226, Jallais C. Effets des humeurs positives et négatives sur les structures de connaissances de type script. Thèse de doctorat non publi

The induction and repair of cyclobutane thymidine dimers in human skin

International Nuclear Information System (INIS)

Roza, L.; Erasmus Univ., Rotterdam; Vermeulen, W.; Schans, G.P. van der; Lohman, P.H.M.

1987-01-01

The most important detrimental effect of ultraviolet radiation (UV) on the living cell, so far known, is the induction of damage in the DNA. The major photoproducts induced in DNA by UV-C (200-280 nm) and UV-B (280-315 nm) are the cyclobutane-type pyrimidine dimers, which have been implicated in UV-induced mutagenesis and carcinogenesis. Dimer lesions in DNA of cells may be repaired in the dark by a multi-enzyme process (excision repair), or via a light dependent enzymatic reaction known as photoreactivation (phr) which is specific for pyrimidine dimers. Although phr has been found to occur in a wide range of organisms, studies on the presence of phr in mammalian cells have yielded conflicting results. To investigate repair of pyrimidine dimers in human skin cells irradiated in vivo, a specific and sensitive detection method was developed based on a monoclonal antibody directed against thymidine dimers. Application together with a fluorescent immunostaining permits the direct detection of thymidine dimers in human skin cells. The method is used in studies aimed at a better understanding of the role of these lesions in the process of carcinogenesis. A report is given on the isolation and characterization of the antibodies, and their application in a study on the induction of pyrimidine dimers in human skin and on photorepair in cultured cells. 10 refs.; 2 figs

Impact of peak/mid luteal estradiol on pregnancy outcome after intracytoplasmic sperm injection

International Nuclear Information System (INIS)

Rehman, R.; Hussain, Z.; Zahir, H.

2014-01-01

Objective: To compare peak to mid estradiol ratio with the probability of successful conception after intra-cytoplasmic sperm injection. Method: The quasi-experimental study was conducted in an infertility clinic at Islamabad from June 2010 till August 2011, and comprised couples subjected to intra-cytoplasmic sperm injection. Down-regulation of ovaries was followed by calculated stimulation, ovulation induction, oocytes retrieval, intra cytoplasmic sperm injection, in vitro maturation of embryos and finally blastocysts transfer. Serum estradiol was measured by enzyme-linked immunosorbent assay on ovulation induction day and the day of embryo transfer. Failure of procedure was detected by beta human chorionic gonadotropin 5-25mIU/ml (Group I; non-pregnant). Females with beta human chorionic gonadotropin>25mIU/ml and no cardiac activity after 4 weeks of transfer were placed in Group II (pre-clinical abortion), and confirmation of foetal heart in the latter comprised Group III (clinical pregnancy). Data was analysed using SPSS 15. Results: Of the 323 couples initially enrolled, embryo transfer was carried out in 282(87.3%) females. Clinical pregnancy was achieved in 101(36%) of the cases, while 61(21.63%) had pre-clinical abortion, and 120(42%) remained non-pregnant. The peak/mid-luteal estradiolratio was low (2.3) in patients who had high oocyte maturity (p=0.001) and fertilisation rate (p=0.003) compared to non-pregnant patients with high peak/mid-luteal estradiolratio (2.56). Conclusion: High peak estradiol with maintenance of optimal levels in mid-luteal phase is required for implantation of fertilised ovum and accomplishment of clinical pregnancy. (author)

Induction accelerator test module for HIF

International Nuclear Information System (INIS)

Faltens, A.

1991-04-01

An induction linac test module suitable for investigating the drive requirements and the longitudinal coupling impedance of a high-power ion induction linac has been constructed by the Heavy Ion Fusion (HIF) group at LBL. The induction linac heavy ion driver for inertial confinement fusion (ICF) as presently envisioned uses multiple parallel beams which are transported in separate focusing channels but accelerated together in the induction modules. The resulting induction modules consequently have large beam apertures-1--2 meters in diameter- and correspondingly large outside diameters. The module geometry is related to a low-frequency ''gap capacity'' and high-frequency structural resonances, which are affected by the magnetic core loading and the module pulser impedance. A description of the test module and preliminary results are presented. 3 figs

Enhanced porcine circovirus Cap protein production by Pichia pastoris with a fuzzy logic DO control based methanol/sorbitol co-feeding induction strategy.

Science.gov (United States)

Ding, Jian; Zhang, Chunling; Gao, Minjie; Hou, Guoli; Liang, Kexue; Li, Chunhua; Ni, Jianping; Li, Zhen; Shi, Zhongping

2014-05-10

Porcine circovirus Cap protein production by P. pastoris with strong AOX promoter suffered with the problems with traditional pure methanol induction: (1) inefficient methanol metabolism; (2) extensive oxygen supply load; (3) difficulty in stable DO control; (4) low protein titer. In this study, based on the difference of DO change patterns in response to methanol and sorbitol additions, a novel fuzzy control system was proposed to automatically regulate the co-feeding rates of methanol and sorbitol for efficient Cap protein induction. With aid of the proposed control system when setting DO control level at 10%, overall fermentation performance was significantly improved: (1) DO could be stably controlled under mild aeration condition; (2) methanol consumption rate could be restricted at moderate level and the major enzymes involved with methanol metabolism were largely activated; (3) Cap protein concentration reached a highest level of 198mg/L, which was about 64% increase over the best one using the pure methanol induction strategies. Copyright © 2014 Elsevier B.V. All rights reserved.

Magnetically responsive enzyme powders

Energy Technology Data Exchange (ETDEWEB)

Pospiskova, Kristyna, E-mail: kristyna.pospiskova@upol.cz [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Safarik, Ivo, E-mail: ivosaf@yahoo.com [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Department of Nanobiotechnology, Institute of Nanobiology and Structural Biology of GCRC, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic)

2015-04-15

Powdered enzymes were transformed into their insoluble magnetic derivatives retaining their catalytic activity. Enzyme powders (e.g., trypsin and lipase) were suspended in various liquid media not allowing their solubilization (e.g., saturated ammonium sulfate and highly concentrated polyethylene glycol solutions, ethanol, methanol, 2-propanol) and subsequently cross-linked with glutaraldehyde. Magnetic modification was successfully performed at low temperature in a freezer (−20 °C) using magnetic iron oxides nano- and microparticles prepared by microwave-assisted synthesis from ferrous sulfate. Magnetized cross-linked enzyme powders were stable at least for two months in water suspension without leakage of fixed magnetic particles. Operational stability of magnetically responsive enzymes during eight repeated reaction cycles was generally without loss of enzyme activity. Separation of magnetically modified cross-linked powdered enzymes from reaction mixtures was significantly simplified due to their magnetic properties. - Highlights: • Cross-linked enzyme powders were prepared in various liquid media. • Insoluble enzymes were magnetized using iron oxides particles. • Magnetic iron oxides particles were prepared by microwave-assisted synthesis. • Magnetic modification was performed under low (freezing) temperature. • Cross-linked powdered trypsin and lipase can be used repeatedly for reaction.

Enzymes in Fermented Fish.

Science.gov (United States)

Giyatmi; Irianto, H E

Fermented fish products are very popular particularly in Southeast Asian countries. These products have unique characteristics, especially in terms of aroma, flavor, and texture developing during fermentation process. Proteolytic enzymes have a main role in hydrolyzing protein into simpler compounds. Fermentation process of fish relies both on naturally occurring enzymes (in the muscle or the intestinal tract) as well as bacteria. Fermented fish products processed using the whole fish show a different characteristic compared to those prepared from headed and gutted fish. Endogenous enzymes like trypsin, chymotrypsin, elastase, and aminopeptidase are the most involved in the fermentation process. Muscle tissue enzymes like cathepsins, peptidases, transaminases, amidases, amino acid decarboxylases, glutamic dehydrogenases, and related enzymes may also play a role in fish fermentation. Due to the decreased bacterial number during fermentation, contribution of microbial enzymes to proteolysis may be expected prior to salting of fish. Commercial enzymes are supplemented during processing for specific purposes, such as quality improvement and process acceleration. In the case of fish sauce, efforts to accelerate fermentation process and to improve product quality have been studied by addition of enzymes such as papain, bromelain, trypsin, pepsin, and chymotrypsin. © 2017 Elsevier Inc. All rights reserved.

Preclinical models for obesity research

Directory of Open Access Journals (Sweden)

Perry Barrett

2016-11-01

Full Text Available A multi-dimensional strategy to tackle the global obesity epidemic requires an in-depth understanding of the mechanisms that underlie this complex condition. Much of the current mechanistic knowledge has arisen from preclinical research performed mostly, but not exclusively, in laboratory mouse and rat strains. These experimental models mimic certain aspects of the human condition and its root causes, particularly the over-consumption of calories and unbalanced diets. As with human obesity, obesity in rodents is the result of complex gene–environment interactions. Here, we review the traditional monogenic models of obesity, their contemporary optogenetic and chemogenetic successors, and the use of dietary manipulations and meal-feeding regimes to recapitulate the complexity of human obesity. We critically appraise the strengths and weaknesses of these different models to explore the underlying mechanisms, including the neural circuits that drive behaviours such as appetite control. We also discuss the use of these models for testing and screening anti-obesity drugs, beneficial bio-actives, and nutritional strategies, with the goal of ultimately translating these findings for the treatment of human obesity.

A systematic review of methodology applied during preclinical anesthetic neurotoxicity studies: important issues and lessons relevant to the design of future clinical research.

Science.gov (United States)

Disma, Nicola; Mondardini, Maria C; Terrando, Niccolò; Absalom, Anthony R; Bilotta, Federico

2016-01-01

Preclinical evidence suggests that anesthetic agents harm the developing brain thereby causing long-term neurocognitive impairments. It is not clear if these findings apply to humans, and retrospective epidemiological studies thus far have failed to show definitive evidence that anesthetic agents are harmful to the developing human brain. The aim of this systematic review was to summarize the preclinical studies published over the past decade, with a focus on methodological issues, to facilitate the comparison between different preclinical studies and inform better design of future trials. The literature search identified 941 articles related to the topic of neurotoxicity. As the primary aim of this systematic review was to compare methodologies applied in animal studies to inform future trials, we excluded a priori all articles focused on putative mechanism of neurotoxicity and the neuroprotective agents. Forty-seven preclinical studies were finally included in this review. Methods used in these studies were highly heterogeneous-animals were exposed to anesthetic agents at different developmental stages, in various doses and in various combinations with other drugs, and overall showed diverse toxicity profiles. Physiological monitoring and maintenance of physiological homeostasis was variable and the use of cognitive tests was generally limited to assessment of specific brain areas, with restricted translational relevance to humans. Comparison between studies is thus complicated by this heterogeneous methodology and the relevance of the combined body of literature to humans remains uncertain. Future preclinical studies should use better standardized methodologies to facilitate transferability of findings from preclinical into clinical science. © 2015 John Wiley & Sons Ltd.

The formation of estrogen-like tamoxifen metabolites and their influence on enzyme activity and gene expression of ADME genes.

Science.gov (United States)

Johänning, Janina; Kröner, Patrick; Thomas, Maria; Zanger, Ulrich M; Nörenberg, Astrid; Eichelbaum, Michel; Schwab, Matthias; Brauch, Hiltrud; Schroth, Werner; Mürdter, Thomas E

2018-03-01

Tamoxifen, a standard therapy for breast cancer, is metabolized to compounds with anti-estrogenic as well as estrogen-like action at the estrogen receptor. Little is known about the formation of estrogen-like metabolites and their biological impact. Thus, we characterized the estrogen-like metabolites tamoxifen bisphenol and metabolite E for their metabolic pathway and their influence on cytochrome P450 activity and ADME gene expression. The formation of tamoxifen bisphenol and metabolite E was studied in human liver microsomes and Supersomes™. Cellular metabolism and impact on CYP enzymes was analyzed in upcyte® hepatocytes. The influence of 5 µM of tamoxifen, anti-estrogenic and estrogen-like metabolites on CYP activity was measured by HPLC MS/MS and on ADME gene expression using RT-PCR analyses. Metabolite E was formed from tamoxifen by CYP2C19, 3A and 1A2 and from desmethyltamoxifen by CYP2D6, 1A2 and 3A. Tamoxifen bisphenol was mainly formed from (E)- and (Z)-metabolite E by CYP2B6 and CYP2C19, respectively. Regarding phase II metabolism, UGT2B7, 1A8 and 1A3 showed highest activity in glucuronidation of tamoxifen bisphenol and metabolite E. Anti-estrogenic metabolites (Z)-4-hydroxytamoxifen, (Z)-endoxifen and (Z)-norendoxifen inhibited the activity of CYP2C enzymes while tamoxifen bisphenol consistently induced CYPs similar to rifampicin and phenobarbital. On the transcript level, highest induction up to 5.6-fold was observed for CYP3A4 by tamoxifen, (Z)-4-hydroxytamoxifen, tamoxifen bisphenol and (E)-metabolite E. Estrogen-like tamoxifen metabolites are formed in CYP-dependent reactions and are further metabolized by glucuronidation. The induction of CYP activity by tamoxifen bisphenol and the inhibition of CYP2C enzymes by anti-estrogenic metabolites may lead to drug-drug-interactions.

Preclinical diagnosis and emergency medical care in case of radiation accidents

International Nuclear Information System (INIS)

Ohlenschlaeger, L.

1990-01-01

Reference is made to preclinical diagnosis and emergency medical care at the site of a potential radiation accident. Possibilities and limits, respectively, of the medical measures are shown. Cooperation between the experts of the technical and medical rescue services is described. Exposition to radiation for the emergency medical staff resulting from the medical care of contaminated persons, is negligible if the personal precautions are observed. (orig.) [de

Thermodynamic activity-based intrinsic enzyme kinetic sheds light on enzyme-solvent interactions.

Science.gov (United States)

Grosch, Jan-Hendrik; Wagner, David; Nistelkas, Vasilios; Spieß, Antje C

2017-01-01

The reaction medium has major impact on biocatalytic reaction systems and on their economic significance. To allow for tailored medium engineering, thermodynamic phenomena, intrinsic enzyme kinetics, and enzyme-solvent interactions have to be discriminated. To this end, enzyme reaction kinetic modeling was coupled with thermodynamic calculations based on investigations of the alcohol dehydrogenase from Lactobacillus brevis (LbADH) in monophasic water/methyl tert-butyl ether (MTBE) mixtures as a model solvent. Substrate concentrations and substrate thermodynamic activities were varied separately to identify the individual thermodynamic and kinetic effects on the enzyme activity. Microkinetic parameters based on concentration and thermodynamic activity were derived to successfully identify a positive effect of MTBE on the availability of the substrate to the enzyme, but a negative effect on the enzyme performance. In conclusion, thermodynamic activity-based kinetic modeling might be a suitable tool to initially curtail the type of enzyme-solvent interactions and thus, a powerful first step to potentially understand the phenomena that occur in nonconventional media in more detail. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:96-103, 2017. © 2016 American Institute of Chemical Engineers.

Profiling the orphan enzymes

Science.gov (United States)

2014-01-01

The emergence of Next Generation Sequencing generates an incredible amount of sequence and great potential for new enzyme discovery. Despite this huge amount of data and the profusion of bioinformatic methods for function prediction, a large part of known enzyme activities is still lacking an associated protein sequence. These particular activities are called “orphan enzymes”. The present review proposes an update of previous surveys on orphan enzymes by mining the current content of public databases. While the percentage of orphan enzyme activities has decreased from 38% to 22% in ten years, there are still more than 1,000 orphans among the 5,000 entries of the Enzyme Commission (EC) classification. Taking into account all the reactions present in metabolic databases, this proportion dramatically increases to reach nearly 50% of orphans and many of them are not associated to a known pathway. We extended our survey to “local orphan enzymes” that are activities which have no representative sequence in a given clade, but have at least one in organisms belonging to other clades. We observe an important bias in Archaea and find that in general more than 30% of the EC activities have incomplete sequence information in at least one superkingdom. To estimate if candidate proteins for local orphans could be retrieved by homology search, we applied a simple strategy based on the PRIAM software and noticed that candidates may be proposed for an important fraction of local orphan enzymes. Finally, by studying relation between protein domains and catalyzed activities, it appears that newly discovered enzymes are mostly associated with already known enzyme domains. Thus, the exploration of the promiscuity and the multifunctional aspect of known enzyme families may solve part of the orphan enzyme issue. We conclude this review with a presentation of recent initiatives in finding proteins for orphan enzymes and in extending the enzyme world by the discovery of new

PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR (PPAR) AGONISTS AS PROMISING NEW MEDICATIONS FOR DRUG ADDICTION: PRECLINICAL EVIDENCE

Science.gov (United States)

Foll, Bernard Le; Ciano, Patricia Di; Panlilio, Leigh V.; Goldberg, Steven R.; Ciccocioppo, Roberto

2013-01-01

This review examines the growing literature on the role of peroxisome proliferator-activated receptors (PPARs) in addiction. There are two subtypes of PPAR receptors that have been studied in addiction: PPAR-α and PPAR-γ. The role of each PPAR subtype in common models of addictive behavior, mainly pre-clinical models, is summarized. In particular, studies are reviewed that investigated the effects of PPAR-α agonists on relapse, sensitization, conditioned place preference, withdrawal and drug intake, and effects of PPAR-γ agonists on relapse, withdrawal and drug intake. Finally, studies that investigated the effects of PPAR agonists on neural pathways of addiction are reviewed. Taken together this preclinical data indicates that PPAR agonists are promising new medications for drug addiction treatment. PMID:23614675

CD26: A Prognostic Marker of Acute Lymphoblastic Leukemia in Children in the Post Remission Induction Phase.

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Mehde, Atheer Awad; Yusof, Faridah; Adel Mehdi, Wesen; Zainulabdeen, Jwan Abdulmohsin

2015-01-01

ALL is an irredeemable disease due to the resistance to treatment. There are several influences which are involved in such resistance to chemotherapy, including oxidative stress as a result of the generation of reactive oxygen species (ROS) and presence of hypodiploid cells. Cluster of differentiation 26 (CD26), also known as dipeptidyl peptidase-4, is a 110 kDa, multifunctional, membrane-bound glycoprotein. The aim of this study was to evaluate the clinical significance of serum CD26 in patients with acute lymphoblastic leukaemia patients in the post remission induction phase, as well as the relationship between CD26 activity and the oxidative stress status. CD26, total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI), in addition to activity of related enzymes myeloperoxidase, glutathione- s-transferase and xanthine oxidase, were analysed in sixty children with acute lymphoblastic leukaemia in the post remission induction phase. The study showed significant elevation in CD26, TOS and OSI levels in patients with acute lymphoblastic leukaemia in the post remission induction phase in comparison to healthy control samples. In contrast, myeloperoxidase, glutathione-s-transferase and xanthine oxidase activities were decreased significantly. A significant correlation between CD26 concentration and some oxidative stress parameters was evident in ALL patients. Serum levels of CD26 appear to be useful as a new biomarker of oxidative stress in children with acute lymphoblastic leukaemia in the post remission induction phase, and levels of antioxidants must be regularly estimated during the treatment of children with ALL.

Omics Meets Biology: Application to the Design and Preclinical Assessment of Antivenoms

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Juan J. Calvete

2014-12-01

Full Text Available Snakebite envenoming represents a neglected tropical disease that has a heavy public health impact worldwide, mostly affecting poor people involved in agricultural activities in Africa, Asia, Latin America and Oceania. A key issue that complicates the treatment of snakebite envenomings is the poor availability of the only validated treatment for this disease, antivenoms. Antivenoms can be an efficacious treatment for snakebite envenoming, provided they are safe, effective, affordable, accessible and administered appropriately. The shortage of antivenoms in various regions, particularly in Sub-Saharan Africa and some parts of Asia, can be significantly alleviated by optimizing the use of current antivenoms and by the generation of novel polyspecific antivenoms having a wide spectrum of efficacy. Complementing preclinical testing of antivenom efficacy using in vivo and in vitro functional neutralization assays, developments in venomics and antivenomics are likely to revolutionize the design and preclinical assessment of antivenoms by being able to test new antivenom preparations and to predict their paraspecific neutralization to the level of species-specific toxins.

How Preclinical Models Evolved to Resemble the Diagnostic Criteria of Drug Addiction.

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Belin-Rauscent, Aude; Fouyssac, Maxime; Bonci, Antonello; Belin, David

2016-01-01

Drug addiction is a complex neuropsychiatric disorder that affects a subset of the individuals who take drugs. It is characterized by maladaptive drug-seeking habits that are maintained despite adverse consequences and intense drug craving. The pathophysiology and etiology of addiction is only partially understood despite extensive research because of the gap between current preclinical models of addiction and the clinical criteria of the disorder. This review presents a brief overview, based on selected methodologies, of how behavioral models have evolved over the last 50 years to the development of recent preclinical models of addiction that more closely mimic diagnostic criteria of addiction. It is hoped that these new models will increase our understanding of the complex neurobiological mechanisms whereby some individuals switch from controlled drug use to compulsive drug-seeking habits and relapse to these maladaptive habits. Additionally, by paving the way to bridge the gap that exists between biobehavioral research on addiction and the human situation, these models may provide new perspectives for the development of novel and effective therapeutic strategies for drug addiction. Published by Elsevier Inc.

Developmental origins of metabolic disorders: The need for biomarker candidates and therapeutic targets from adequate preclinical models

Directory of Open Access Journals (Sweden)

Antonio Gonzalez-Bulnes

2016-03-01

Full Text Available The investigation on obesity and associated disorders have changed from an scenario in which genome drove the phenotype to a dynamic setup in which prenatal and early-postnatal conditions are determinant. However, research in human beings is difficult due to confounding factors (lifestyle and socioeconomic heterogeneity plus ethical issues. Hence, there is currently an intensive effort for developing adequate preclinical models, aiming for an adequate combination of basic studies in rodent models and specific preclinical studies in large animals. The results of these research strategies may increase the identification and development of contrasted biomarkers and therapeutic targets.

Applications of the Preclinical Molecular Imaging in Biomedicine: Gene Therapy

International Nuclear Information System (INIS)

Collantes, M.; Peñuelas, I.

2014-01-01

Gene therapy constitutes a promising option for efficient and targeted treatment of several inherited disorders. Imaging techniques using ionizing radiation as PET or SPECT are used for non-invasive monitoring of the distribution and kinetics of vector-mediated gene expression. In this review the main reporter gene/reporter probe strategies are summarized, as well as the contribution of preclinical models to the development of this new imaging modality previously to its application in clinical arena. [es

Multimodal imaging of bone metastases: From preclinical to clinical applications

Directory of Open Access Journals (Sweden)

Stephan Ellmann

2015-10-01

Full Text Available Metastases to the skeletal system are commonly observed in cancer patients, highly affecting the patients' quality of life. Imaging plays a major role in detection, follow-up, and molecular characterisation of metastatic disease. Thus, imaging techniques have been optimised and combined in a multimodal and multiparametric manner for assessment of complementary aspects in osseous metastases. This review summarises both application of the most relevant imaging techniques for bone metastasis in preclinical models and the clinical setting.

Induction of ovulation by a potent, orally active, low molecular weight agonist (Org 43553) of the luteinizing hormone receptor.

Science.gov (United States)

van de Lagemaat, R; Timmers, C M; Kelder, J; van Koppen, C; Mosselman, S; Hanssen, R G J M

2009-03-01

In assisted reproductive technology, human chorionic gonadotrophin (hCG) is administered subcutaneously for the induction of oocyte maturation and ovulation. Our efforts to develop orally bioavailable luteinizing hormone (LH) receptor agonists have led to the discovery of Org 43553, a low molecular weight (LMW) LH receptor (LH-R) agonist. Org 43553 was tested in vitro and in vivo in pre-clinical pharmacological models to demonstrate efficacy and oral availability. Org 43553 is a potent stimulator of the human LH-R in vitro (EC(50) 3.7 nM). In primary mouse Leydig cells, Org 43553 stimulated testosterone production. Pharmacokinetic analyses showed high oral bioavailability in rats (79%) and dogs (44%) with a shorter half-life compared with hCG (3.4 versus 5.6 h in the rat). Ovulation induction by Org 43553 was demonstrated in immature mice as well as in cyclic rats after single-dose oral administration (50 mg/kg). The ovulated oocytes were of good quality as demonstrated by successful fertilization and implantation of normal embryos. In male rats, testosterone production was substantially induced after oral administration. Org 43553 is the first LMW LH-R mimetic with demonstrated in vivo efficacy upon oral administration and could therefore replace subcutaneously administered hCG. The elimination half-life of Org 43553 is substantially shorter than hCG, which could potentially represent a clinical benefit in reducing the risk of ovarian hyperstimulation syndrome (OHSS).

The predictive validity of the BioMedical Admissions Test for pre-clinical examination performance.

Science.gov (United States)

Emery, Joanne L; Bell, John F

2009-06-01

Some medical courses in the UK have many more applicants than places and almost all applicants have the highest possible previous and predicted examination grades. The BioMedical Admissions Test (BMAT) was designed to assist in the student selection process specifically for a number of 'traditional' medical courses with clear pre-clinical and clinical phases and a strong focus on science teaching in the early years. It is intended to supplement the information provided by examination results, interviews and personal statements. This paper reports on the predictive validity of the BMAT and its predecessor, the Medical and Veterinary Admissions Test. Results from the earliest 4 years of the test (2000-2003) were matched to the pre-clinical examination results of those accepted onto the medical course at the University of Cambridge. Correlation and logistic regression analyses were performed for each cohort. Section 2 of the test ('Scientific Knowledge') correlated more strongly with examination marks than did Section 1 ('Aptitude and Skills'). It also had a stronger relationship with the probability of achieving the highest examination class. The BMAT and its predecessor demonstrate predictive validity for the pre-clinical years of the medical course at the University of Cambridge. The test identifies important differences in skills and knowledge between candidates, not shown by their previous attainment, which predict their examination performance. It is thus a valid source of additional admissions information for medical courses with a strong scientific emphasis when previous attainment is very high.

Preclinical magnetic resonance imaging and systems biology in cancer research: current applications and challenges.

Science.gov (United States)

Albanese, Chris; Rodriguez, Olga C; VanMeter, John; Fricke, Stanley T; Rood, Brian R; Lee, YiChien; Wang, Sean S; Madhavan, Subha; Gusev, Yuriy; Petricoin, Emanuel F; Wang, Yue

2013-02-01

Biologically accurate mouse models of human cancer have become important tools for the study of human disease. The anatomical location of various target organs, such as brain, pancreas, and prostate, makes determination of disease status difficult. Imaging modalities, such as magnetic resonance imaging, can greatly enhance diagnosis, and longitudinal imaging of tumor progression is an important source of experimental data. Even in models where the tumors arise in areas that permit visual determination of tumorigenesis, longitudinal anatomical and functional imaging can enhance the scope of studies by facilitating the assessment of biological alterations, (such as changes in angiogenesis, metabolism, cellular invasion) as well as tissue perfusion and diffusion. One of the challenges in preclinical imaging is the development of infrastructural platforms required for integrating in vivo imaging and therapeutic response data with ex vivo pathological and molecular data using a more systems-based multiscale modeling approach. Further challenges exist in integrating these data for computational modeling to better understand the pathobiology of cancer and to better affect its cure. We review the current applications of preclinical imaging and discuss the implications of applying functional imaging to visualize cancer progression and treatment. Finally, we provide new data from an ongoing preclinical drug study demonstrating how multiscale modeling can lead to a more comprehensive understanding of cancer biology and therapy. Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Evaluating the short-term effects of a communication skills program for preclinical medical students.

Science.gov (United States)

Lee, Young-Mee; Lee, Young Hee

2014-09-01

Regardless of the growing importance of communication skills as a core clinical competence, few studies have determined the effects of communication skills courses in undergraduate medical curricula in Asian medical schools. The purpose of this study was to examine the effectiveness of a communication skills program for preclinical medical students. A communication skills course was provided to 111 second-year medical students in a medical college in Korea. Students' self-assessed competency of communication skills was evaluated by a questionnaire survey. To examine the improvement in observed communication skills, the students' encounters with standardized patients (SPs) were assessed at the first session and at the final course assessment. A structured checklist, consisting of 25 communication skills items, was used for the assessment. Students' self-assessed competency of communication skills increased significantly after completion of the course (pcommunication skills scores also improved significantly at the end of the course; the mean scores of the first SPs encounters was 49.6 (standard deviation [SD], 11.1), and those of cases A and B at the final assessment were 61.5 (SD, 8.4) and 69.6 (SD, 7.8), respectively (F61=269.54, pcommunication skills course was beneficial in developing and improving communication skills competency in preclinical medical students. Further studies should be followed to examine whether the acquisition of communication skills during preclinical studies can be sustained into clerkship and actual practice.

Inductive Loops for Sensing Position as Signature Signals

International Nuclear Information System (INIS)

Larbani, Sofiane; Malik, Noreha Abdul; Nordin, Anis Norashikin; Khan, Sheroz; Shobaki, Mohammad

2013-01-01

In this paper, an inductive sensing technique made of a special shaped inductive loop is proposed. The inductive loop has an inner turn fitted within an outer turn, making a total inductance value 100μH. This loop is made to be shown with balanced response using three capacitance values of 0.068μF each when a sinusoidal voltage source of 5V peak-to-peak is applied. The variation of the relative permeability of the inductance of the inductive loop (AL) results in a variation of the overall inductance value (L+AL), that causes the output signal to change in term of shape and amplitude for variation of total inductance sweep over a given period of time. As a result of change in inductance value (lμH) there is a correspondence increase of 300mV. Theoretical derivations have showed in close agreement with the simulation plots obtained using Multisim software

Inductive Loops for Sensing Position as Signature Signals

Science.gov (United States)

Larbani, Sofiane; Malik, Noreha Abdul; Norashikin Nordin, Anis; Khan, Sheroz; Shobaki, Mohammad

2013-12-01

In this paper, an inductive sensing technique made of a special shaped inductive loop is proposed. The inductive loop has an inner turn fitted within an outer turn, making a total inductance value 100μH. This loop is made to be shown with balanced response using three capacitance values of 0.068μF each when a sinusoidal voltage source of 5V peak-to-peak is applied. The variation of the relative permeability of the inductance of the inductive loop (AL) results in a variation of the overall inductance value (L+AL), that causes the output signal to change in term of shape and amplitude for variation of total inductance sweep over a given period of time. As a result of change in inductance value (lμH) there is a correspondence increase of 300mV. Theoretical derivations have showed in close agreement with the simulation plots obtained using Multisim software.

Lack of induction of tissue transglutaminase but activation of the preexisting enzyme in c-Myc-induced apoptosis of CHO cells.

Science.gov (United States)

Balajthy, Z; Kedei, N; Nagy, L; Davies, P J; Fésüs, L

1997-07-18

The intracellular activity and expression of tissue transglutaminase, which crosslinks proteins through epsilon(gamma-glutamyl)lysine isodipeptide bond, was investigated in CHO cells and those stably transfected with either inducible c-Myc (which leads to apoptosis) or with c-myc and the apoptosis inhibitor Bcl-2. Protein-bound cross-link content was significantly higher when apoptosis was induced by c-Myc while the concomitant presence of Bcl-2 markedly reduced both apoptosis and enzymatic protein cross-linking. The expression of tissue transglutaminase did not change following the initiation of apoptosis by c-Myc or when it was blocked by Bcl-2. Studying transiently co-transfected elements of the mouse tissue transglutaminase promoter linked to a reporter enzyme revealed their overall repression in cells expressing c-Myc. This repression was partially suspended in cells also carrying Bcl-2. Our data suggest that tissue transglutaminase is not induced when c-Myc initiates apoptosis but the pre-existing endogenous enzyme is activated.

Neural induction with neurogenin 1 enhances the therapeutic potential of mesenchymal stem cells in an amyotrophic lateral sclerosis mouse model.

Science.gov (United States)

Chan-Il, Choi; Young-Don, Lee; Heejaung, Kim; Kim, Seung Hyun; Suh-Kim, Haeyoung; Kim, Sung-Soo

2013-01-01

Amyotrophic lateral sclerosis (ALS) is characterized by progressive dysfunction and degeneration of motor neurons in the central nervous system (CNS). In the absence of effective drug treatments for ALS, stem cell treatment has emerged as a candidate therapy for this disease. To date, however, there is no consensus protocol that stipulates stem cell types, transplantation timing, or frequency. Using an ALS mouse model carrying a high copy number of a mutant human superoxide dismutase-1 (SOD1)(G93A) transgene, we investigated the effect of neural induction on the innate therapeutic potential of mesenchymal stem cells (MSCs) in relation to preclinical transplantation parameters. In our study, the expression of monocyte chemoattractant protein-1 (MCP-1) was elevated in the ALS mouse spinal cord. Neural induction of MSCs with neurogenin 1 (Ngn1) upregulated the expression level of the MCP-1 receptor, CCR2, and enhanced the migration activity toward MCP-1 in vitro. Ngn1-expressing MSCs (MSCs-Ngn1) showed a corresponding increase in tropism to the CNS after systemic transplantation in ALS mice. Notably, MSCs-Ngn1 delayed disease onset if transplanted during preonset ages,whereas unprocessed MSCs failed to do so. If transplanted near the onset ages, a single treatment with MSCs-Ngn1 was sufficient to enhance motor functions during the symptomatic period (15–17 weeks), whereas unprocessed MSCs required repeated transplantation to achieve similar levels of motor function improvement. Our data indicate that systemically transplanted MSCs-Ngn1 can migrate to the CNS and exert beneficial effects on host neural cells for an extended period of time through paracrine functions, suggesting a potential benefit of neural induction of transplanted MSCs in long-term treatment of ALS.

Effect of irradiation on immobilized enzymes compared with that on enzymes in solution

International Nuclear Information System (INIS)

Schachinger, L.; Schippel, C.; Altmann, E.; Diepold, B.; Yang, C.; Jaenike, M.; Hochhaeuser, E.

1985-01-01

Glucose oxidase and catalase were immobilized by attaching them to nylon fibers that had been treated with triethyloxonium-tetrafluoroborate, diaminohexane and glutaraldialdehyde according to Morris, Campell and Hornby (1975). This method assures that the enzymes are bound to a side chain of the polyamide structure. Enzyme activity (as measured by the O 2 -uptake and by microcalorimetry) was found to be unchanged after 2 years. The apparent Ksub(m)-constants of the immobilized enzymes with glucose were the same as those for enzymes in solution. GOD and catalase immobilized in poly(acrylamide) gel had the same Ksub(m)-value. Despite the high stability during storage, the radiation induced inactivation of enzymes immobilized on gel or chromosorb, an inorganic carrier, was of the same order of magnitude as that of the dissolved enzymes. The enzymes bound to nylon fibers showed a higher radiation sensitivity. This might have been caused by an additional attack on the binding site of the carrier. (orig.)

Inductive Communication System Design Summary

Science.gov (United States)

1978-09-01

The report documents the experience obtained during the design and development of the Inductive Communications System used in the Morgantown People Mover. The Inductive Communications System is used to provide wayside-to-vehicle and vehicle-to-waysid...

Comparative studies on the induction of Trichoderma harzianum mutanase by α-(1→3)-glucan-rich fruiting bodies and mycelia of Laetiporus sulphureus.

Science.gov (United States)

Wiater, Adrian; Pleszczyńska, Małgorzata; Szczodrak, Janusz; Janusz, Grzegorz

2012-01-01

Mutanase (α-(1→3)-glucanase) is a little-known inductive enzyme that is potentially useful in dentistry. Here, it was shown that the cell wall preparation (CWP) obtained from the fruiting body or vegetative mycelium of polypore fungus Laetiporus sulphureus is rich in α-(1→3)-glucan and can be successfully used for mutanase induction in Trichoderma harzianum. The content of this biopolymer in the CWP depended on the age of fruiting bodies and increased along with their maturation. In the case of CWP prepared from vegetative mycelia, the amount of α-(1→3)-glucan depended on the mycelium age and also on the kind of medium used for its cultivation. All CWPs prepared from the individually harvested fruiting body specimens induced high mutanase activity (0.53-0.82 U/mL) in T. harzianum after 3 days of cultivation. As for the CWPs obtained from the hyphal mycelia of L. sulpureus, the maximal enzyme productivity (0.34 U/mL after 3 days of incubation) was recorded for CWP prepared from the 3 week-old mycelium cultivated in Sabouraud medium. Statistically, a high positive correlation was found between the total percentage content of α-(1→3)-glucan in the CWP and the mutanase activity.

A student-initiated and student-facilitated international health elective for preclinical medical students

Directory of Open Access Journals (Sweden)

Nirali Vora

2010-02-01

Full Text Available Introduction: Global health education is becoming more important for developing well-rounded physicians and may encourage students toward a career in primary care. Many medical schools, however, lack adequate and structured opportunities for students beginning the curriculum. Methods: Second-year medical students initiated, designed, and facilitated a pass–fail international health elective, providing a curricular framework for preclinical medical students wishing to gain exposure to the clinical and cultural practices of a developing country. Results: All course participants (N=30 completed a post-travel questionnaire within one week of sharing their experiences. Screening reflection essays for common themes that fulfill university core competencies yielded specific global health learning outcomes, including analysis of health care determinants. Conclusion: Medical students successfully implemented a sustainable global health curriculum for preclinical student peers. Financial constraints, language, and organizational burdens limit student participation. In future, long-term studies should analyze career impact and benefits to the host country.

Pre-clinical research in small animals using radiotherapy technology--a bidirectional translational approach.

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Tillner, Falk; Thute, Prasad; Bütof, Rebecca; Krause, Mechthild; Enghardt, Wolfgang

2014-12-01

For translational cancer research, pre-clinical in-vivo studies using small animals have become indispensable in bridging the gap between in-vitro cell experiments and clinical implementation. When setting up such small animal experiments, various biological, technical and methodical aspects have to be considered. In this work we present a comprehensive topical review based on relevant publications on irradiation techniques used for pre-clinical cancer research in mice and rats. Clinical radiotherapy treatment devices for the application of external beam radiotherapy and brachytherapy as well as dedicated research irradiation devices are feasible for small animal irradiation depending on the animal model and the experimental goals. In this work, appropriate solutions for the technological transfer of human radiation oncology to small animal radiation research are summarised. Additionally, important information concerning the experimental design is provided such that reliable and clinically relevant results can be attained. Copyright © 2014. Published by Elsevier GmbH.

Modeling and analysis with induction generators

CERN Document Server

Simões, M Godoy

2014-01-01

ForewordPrefaceAcknowledgmentsAuthorsPrinciples of Alternative Sources of Energy and Electric GenerationScope of This ChapterLegal DefinitionsPrinciples of Electrical ConversionBasic Definitions of Electrical PowerCharacteristics of Primary SourcesCharacteristics of Remote Industrial, Commercial, and Residential Sites and Rural EnergySelection of the Electric GeneratorInterfacing Primary Source, Generator, and LoadExample of a Simple Integrated Generating and Energy-Storing SystemSolved ProblemsSuggested ProblemsReferencesSteady-State Model of Induction GeneratorsScope of This ChapterInterconnection and Disconnection of the Electric Distribution NetworkRobustness of Induction GeneratorsClassical Steady-State Representation of the Asynchronous MachineGenerated PowerInduced TorqueRepresentation of Induction Generator LossesMeasurement of Induction Generator ParametersBlocked Rotor Test (s = 1)No-Load Test (s = 0)Features of Induction Machines Working as Generators Interconnected to the Distribution NetworkHigh-...

Hypnosis for induction of labour.

Science.gov (United States)

Nishi, Daisuke; Shirakawa, Miyako N; Ota, Erika; Hanada, Nobutsugu; Mori, Rintaro

2014-08-14

Induction of labour using pharmacological and mechanical methods can increase complications. Complementary and alternative medicine methods including hypnosis may have the potential to provide a safe alternative option for the induction of labour. However, the effectiveness of hypnosis for inducing labour has not yet been fully evaluated. To assess the effect of hypnosis for induction of labour compared with no intervention or any other interventions. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2014), handsearched relevant conference proceedings, contacted key personnel and organisations in the field for published and unpublished references. All published and unpublished randomised controlled trials (RCTs) and cluster-RCTs of acceptable quality comparing hypnosis with no intervention or any other interventions, in which the primary outcome is to assess whether labour was induced. Two review authors assessed the one trial report that was identified (but was subsequently excluded). No RCTs or cluster-RCTs were identified from the search strategy. There was no evidence available from RCTs to assess the effect of hypnosis for induction of labour. Evidence from RCTs is required to evaluate the effectiveness and safety of this intervention for labour induction. As hypnosis may delay standard care (in case standard care is withheld during hypnosis), its use in induction of labour should be considered on a case-by-case basis.Future RCTs are required to examine the effectiveness and safety of hypnotic relaxation for induction of labour among pregnant women who have anxiety above a certain level. The length and timing of the intervention, as well as the staff training required, should be taken into consideration. Moreover, the views and experiences of women and staff should also be included in future RCTs.

Preclinical Justification of pbi-shRNA EWS/FLI1 Lipoplex (LPX) Treatment for Ewing's Sarcoma.

Science.gov (United States)

Rao, Donald D; Jay, Christopher; Wang, Zhaohui; Luo, Xiuquan; Kumar, Padmasini; Eysenbach, Hilary; Ghisoli, Maurizio; Senzer, Neil; Nemunaitis, John

2016-08-01

The EWS/FLI1 fusion gene is well characterized as a driver of Ewing's sarcoma. Bi-shRNA EWS/FLI1 is a functional plasmid DNA construct that transcribes both siRNA and miRNA-like effectors each of which targets the identical type 1 translocation junction region of the EWS/FLI1 transcribed mRNA sequence. Previous preclinical and clinical studies confirm the safety of this RNA interference platform technology and consistently demonstrate designated mRNA and protein target knockdown at greater than 90% efficiency. We initiated development of pbi-shRNA EWS/FLI1 lipoplex (LPX) for the treatment of type 1 Ewing's sarcoma. Clinical-grade plasmid was manufactured and both sequence and activity verified. Target protein and RNA knockdown of 85-92% was demonstrated in vitro in type 1 human Ewing's sarcoma tumor cell lines with the optimal bi-shRNA EWS/FLI1 plasmid. This functional plasmid was placed in a clinically tested, liposomal (LP) delivery vehicle followed by in vivo verification of activity. Type 1 Ewing's sarcoma xenograft modeling confirmed dose related safety and tumor response to pbi-shRNA EWS/FLI1 LPX. Toxicology studies in mini-pigs with doses comparable to the demonstrated in vivo efficacy dose resulted in transient fever, occasional limited hypertension at low- and high-dose assessment and transient liver enzyme elevation at high dose. These results provide the justification to initiate clinical testing.

Direct Electron Transfer of Enzymes in a Biologically Assembled Conductive Nanomesh Enzyme Platform.

Science.gov (United States)

Lee, Seung-Woo; Lee, Ki-Young; Song, Yong-Won; Choi, Won Kook; Chang, Joonyeon; Yi, Hyunjung

2016-02-24

Nondestructive assembly of a nanostructured enzyme platform is developed in combination of the specific biomolecular attraction and electrostatic coupling for highly efficient direct electron transfer (DET) of enzymes with unprecedented applicability and versatility. The biologically assembled conductive nanomesh enzyme platform enables DET-based flexible integrated biosensors and DET of eight different enzyme with various catalytic activities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Near-peers improve patient safety training in the preclinical curriculum.

Science.gov (United States)

Raty, Sally R; Teal, Cayla R; Nelson, Elizabeth A; Gill, Anne C

2017-01-01

Accrediting bodies require medical schools to teach patient safety and residents to develop teaching skills in patient safety. We created a patient safety course in the preclinical curriculum and used continuous quality improvement to make changes over time. To assess the impact of resident teaching on student perceptions of a Patient Safety course. Using the Institute for Healthcare Improvement patient safety curriculum as a frame, the course included the seven IHI modules, large group lectures and small group facilitated discussions. Applying a social action methodology, we evaluated the course for four years (Y1-Y4). In Y1, Y2, Y3 and Y4, we distributed a course evaluation to each student (n = 184, 189, 191, and 184, respectively) and the response rate was 96, 97, 95 and 100%, respectively. Overall course quality, clarity of course goals and value of small group discussions increased in Y2 after the introduction of residents as small group facilitators. The value of residents and the overall value of the course increased in Y3 after we provided residents with small group facilitation training. Preclinical students value the interaction with residents and may perceive the overall value of a course to be improved based on near-peer involvement. Residents gain valuable experience in small group facilitation and leadership.

Left ventricular remodeling in preclinical experimental mitral regurgitation of dogs.

Science.gov (United States)

Dillon, A Ray; Dell'Italia, Louis J; Tillson, Michael; Killingsworth, Cheryl; Denney, Thomas; Hathcock, John; Botzman, Logan

2012-03-01

Dogs with experimental mitral regurgitation (MR) provide insights into the left ventricular remodeling in preclinical MR. The early preclinical left ventricular (LV) changes after mitral regurgitation represent progressive dysfunctional remodeling, in that no compensatory response returns the functional stroke volume (SV) to normal even as total SV increases. The gradual disease progression leads to mitral annulus stretch and enlargement of the regurgitant orifice, further increasing the regurgitant volume. Remodeling with loss of collagen weave and extracellular matrix (ECM) is accompanied by stretching and hypertrophy of the cross-sectional area and length of the cardiomyocyte. Isolated ventricular cardiomyocytes demonstrate dysfunction based on decreased cell shortening and reduced intracellular calcium transients before chamber enlargement or decreases in contractility in the whole heart can be clinically appreciated. The genetic response to increased end-diastolic pressure is down-regulation of genes associated with support of the collagen and ECM and up-regulation of genes associated with matrix remodeling. Experiments have not demonstrated any beneficial effects on remodeling from treatments that decrease afterload via blocking the renin-angiotensin system (RAS). Beta-1 receptor blockade and chymase inhibition have altered the progression of the LV remodeling and have supported cardiomyocyte function. The geometry of the LV during the remodeling provides insight into the importance of regional differences in responses to wall stress. Copyright © 2012 Elsevier B.V. All rights reserved.

Pre-clinical medical student experience in a pediatric pulmonary clinic

Directory of Open Access Journals (Sweden)

Thomas G. Saba

2015-11-01

Full Text Available Objective: Our objective was to evaluate the educational value of introducing pre-clinical medical students to pediatric patients and their families in a subspecialty clinic setting. Methods: First- and second-year medical students at the University of Michigan seeking clinical experience outside of the classroom attended an outpatient pediatric pulmonary clinic. Evaluation of the experience consisted of pre- and post-clinic student surveys and post-clinic parent surveys with statements employing a four-point Likert scale as well as open-ended questions. Results: Twenty-eight first-year students, 6 second-year students, and 33 parents participated in the study. Post-clinic statement scores significantly increased for statements addressing empathic attitudes, confidence communicating with children and families, comfort in the clinical environment, and social awareness. Scores did not change for statements addressing motivation, a sense of team membership, or confidence with career goals. Students achieved their goals of gaining experience interacting with patients, learning about pulmonary diseases, and observing clinic workflow. Parents felt that they contributed to student education and were not inconvenienced. Conclusions: Students identified several educational benefits of exposure to a single pediatric pulmonary clinic. Patients and families were not inconvenienced by the participation of a student. Additional studies are warranted to further investigate the value of this model of pre-clinical medical student exposure to subspecialty pediatrics.

Enzymes for improved biomass conversion

Science.gov (United States)

Brunecky, Roman; Himmel, Michael E.

2016-02-02

Disclosed herein are enzymes and combinations of the enzymes useful for the hydrolysis of cellulose and the conversion of biomass. Methods of degrading cellulose and biomass using enzymes and cocktails of enzymes are also disclosed.

Mode of action analysis for the synthetic pyrethroid metofluthrin-induced rat liver tumors: evidence for hepatic CYP2B induction and hepatocyte proliferation.

Science.gov (United States)

Deguchi, Yoshihito; Yamada, Tomoya; Hirose, Yukihiro; Nagahori, Hirohisa; Kushida, Masahiko; Sumida, Kayo; Sukata, Tokuo; Tomigahara, Yoshitaka; Nishioka, Kazuhiko; Uwagawa, Satoshi; Kawamura, Satoshi; Okuno, Yasuyoshi

2009-03-01

Two-year treatment with high doses of Metofluthrin produced hepatocellular tumors in both sexes of Wistar rats. To understand the mode of action (MOA) by which the tumors are produced, a series of studies examined the effects of Metofluthrin on hepatic microsomal cytochrome P450 (CYP) content, hepatocellular proliferation, hepatic gap junctional intercellular communication (GJIC), oxidative stress and apoptosis was conducted after one or two weeks of treatment. The global gene expression profile indicated that most genes with upregulated expression with Metofluthrin were metabolic enzymes that were also upregulated with phenobarbital. Metofluthrin induced CYP2B and increased liver weights associated with centrilobular hepatocyte hypertrophy (increased smooth endoplasmic reticulum [SER]), and induction of increased hepatocellular DNA replication. CYP2B1 mRNA induction by Metofluthrin was not observed in CAR knockdown rat hepatocytes using the RNA interference technique, demonstrating that Metofluthrin induces CYP2B1 through CAR activation. Metofluthrin also suppressed hepatic GJIC and induced oxidative stress and increased antioxidant enzymes, but showed no alteration in apoptosis. The above parameters related to the key events in Metofluthrin-induced liver tumors were observed at or below tumorigenic dose levels. All of these effects were reversible upon cessation of treatment. Metofluthrin did not cause cytotoxicity or peroxisome proliferation. Thus, it is highly likely that the MOA for Metofluthrin-induced liver tumors in rats is through CYP induction and increased hepatocyte proliferation, similar to that seen for phenobarbital. Based on analysis with the International Life Sciences Institute/Risk Science Institute MOA framework, it is reasonable to conclude that Metofluthrin will not have any hepatocarcinogenic activity in humans, at least at expected levels of exposure.

Improvement of Aspergillus niger 55, a raw corn meal saccharifying enzyme hyperproducer, through mutation and selective screening techniques

International Nuclear Information System (INIS)

Oh, S.H.; O, P.S.

1991-01-01

Mutation experiments were performed to select the mutant of Aspergillus niger 55, which had lost almost all the ability to produce transglucosidases but retained that of high productivity of raw meal saccharifying enzyme, by means of successive induction with N-methyl-N'-nitro-N-nitrosoguanidine(MNNG), ultraviolet(UV) light, and γ-rays. Also, we used the mutant enrichment techniques, such as liquid culture-filtration procedure and differential heat sensitivity of conidia, in order to increase the possibility of obtaining a mutant. The glucoamylase productivity of mutant PFST-38 was 11 times higher than that of the parent strain. The mutant PFST-38 was morphologically identical to the parent strain, except for the size of conidia, the tendency to form conidia and the length of conidiophore. Asp. niger mutant PFST-38 appeared to be useful for the submerged production of the raw corn meal saccharifying enzyme

Discovery of VU0467485/AZ13713945: An M4 PAM Evaluated as a Preclinical Candidate for the Treatment of Schizophrenia.

Science.gov (United States)

Wood, Michael R; Noetzel, Meredith J; Melancon, Bruce J; Poslusney, Michael S; Nance, Kellie D; Hurtado, Miguel A; Luscombe, Vincent B; Weiner, Rebecca L; Rodriguez, Alice L; Lamsal, Atin; Chang, Sichen; Bubser, Michael; Blobaum, Anna L; Engers, Darren W; Niswender, Colleen M; Jones, Carrie K; Brandon, Nicholas J; Wood, Michael W; Duggan, Mark E; Conn, P Jeffrey; Bridges, Thomas M; Lindsley, Craig W

2017-02-09

Herein, we report the structure-activity relationships within a series of potent, selective, and orally bioavailable muscarinic acetylcholine receptor 4 (M 4 ) positive allosteric modulators (PAMs). Compound 6c (VU0467485) possesses robust in vitro M 4 PAM potency across species and in vivo efficacy in preclinical models of schizophrenia. Coupled with an attractive DMPK profile and suitable predicted human PK, 6c (VU0467485) was evaluated as a preclinical development candidate.

Thinking through postoperative cognitive dysfunction: How to bridge the gap between clinical and pre-clinical perspectives.

Science.gov (United States)

Hovens, Iris B; Schoemaker, Regien G; van der Zee, Eddy A; Heineman, Erik; Izaks, Gerbrand J; van Leeuwen, Barbara L

2012-10-01

Following surgery, patients may experience cognitive decline, which can seriously reduce quality of life. This postoperative cognitive dysfunction (POCD) is mainly seen in the elderly and is thought to be mediated by surgery-induced inflammatory reactions. Clinical studies tend to define POCD as a persisting, generalised decline in cognition, without specifying which cognitive functions are impaired. Pre-clinical research mainly describes early hippocampal dysfunction as a consequence of surgery-induced neuroinflammation. These different approaches to study POCD impede translation between clinical and pre-clinical research outcomes and may hamper the development of appropriate interventions. This article analyses which cognitive domains deteriorate after surgery and which brain areas might be involved. The most important outcomes are: (1) POCD encompasses a wide range of cognitive impairments; (2) POCD affects larger areas of the brain; and (3) individual variation in the vulnerability of neuronal networks to neuroinflammatory mechanisms may determine if and how POCD manifests itself. We argue that, for pre-clinical and clinical research of POCD to advance, the effects of surgery on various cognitive functions and brain areas should be studied. Moreover, in addition to general characteristics, research should take inter-relationships between cognitive complaints and physical and mental characteristics into account. Copyright © 2012 Elsevier Inc. All rights reserved.

In question: the scientific value of preclinical safety pharmacology and toxicology studies with cell-based therapies

Directory of Open Access Journals (Sweden)

Christiane Broichhausen

2014-01-01

Full Text Available A new cell-based medicinal product containing human regulatory macrophages, known as Mreg_UKR, has been developed and conforms to expectations of a therapeutic drug. Here, Mreg_UKR was subjected to pharmacokinetic, safety pharmacology, and toxicological testing, which identified no adverse reactions. These results would normally be interpreted as evidence of the probable clinical safety of Mreg_UKR; however, we contend that, owing to their uncertain biological relevance, our data do not fully support this conclusion. This leads us to question whether there is adequate scientific justification for preclinical safety testing of similar novel cell-based medicinal products using animal models. In earlier work, two patients were treated with regulatory macrophages prior to kidney transplantation. In our opinion, the absence of acute or chronic adverse effects in these cases is the most convincing available evidence of the likely safety of Mreg_UKR in future recipients. On this basis, we consider that safety information from previous clinical investigations of related cell products should carry greater weight than preclinical data when evaluating the safety profile of novel cell-based medicinal products. By extension, we argue that omitting extensive preclinical safety studies before conducting small-scale exploratory clinical investigations of novel cell-based medicinal products data may be justifiable in some instances.

Pre-clinical therapeutic development of a series of metalloporphyrins for Parkinson's disease

International Nuclear Information System (INIS)

Liang, Li-Ping; Huang, Jie; Fulton, Ruth; Pearson-Smith, Jennifer N.; Day, Brian J.; Patel, Manisha

2017-01-01

Reactive oxygen species are a well-defined therapeutic target for Parkinson's disease (PD) and pharmacological agents that catalytically scavenge reactive species are promising neuroprotective strategies for treatment. Metalloporphyrins are synthetic catalytic antioxidants that mimic the body's own antioxidant enzymes i.e. superoxide dismutases and catalase. The goal of this study was to determine if newly designed metalloporphyrins have enhanced pharmacodynamics including oral bioavailability, longer plasma elimination half-lives, penetrate the blood brain barrier, and show promise for PD treatment. Three metalloporphyrins (AEOL 11216, AEOL 11203 and AEOL 11114) were identified in this study as potential candidates for further pre-clinical development. Each of these compounds demonstrated blood brain barrier permeability by the i.p. route and two of three compounds (AEOL 11203 and AEOL 11114) were orally bioavailable. All of these compounds protected against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity, including dopamine depletion in the striatum, dopaminergic neuronal loss in the substantial nigra, and increased oxidative/nitrative stress indices (glutathione disulfide and 3-nitrotyrosine) in the ventral midbrain of the mice without inhibiting MPTP metabolism. Daily therapeutic dosing of these metalloporphyrins were well tolerated without accumulation of brain manganese levels or behavioral alterations assessed by open field and rotarod tests. The study identified two orally active metalloporphyrins and one injectable metalloporphyrin as clinical candidates for further development in PD. - Highlights: • A series of metalloporphyrins were optimized in a mouse model of parkinsonism. • Two novel orally active, brain permeable antioxidant metalloporphyrins were identified. • The identified metalloporphyrins were well tolerated.

Pre-clinical therapeutic development of a series of metalloporphyrins for Parkinson's disease

Energy Technology Data Exchange (ETDEWEB)

Liang, Li-Ping [Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO (United States); Huang, Jie [Department of Medicine, National Jewish Health, Denver, CO (United States); Fulton, Ruth; Pearson-Smith, Jennifer N. [Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO (United States); Day, Brian J. [Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO (United States); Department of Medicine, National Jewish Health, Denver, CO (United States); Patel, Manisha, E-mail: manisha.patel@ucdenver.edu [Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO (United States)

2017-07-01

Reactive oxygen species are a well-defined therapeutic target for Parkinson's disease (PD) and pharmacological agents that catalytically scavenge reactive species are promising neuroprotective strategies for treatment. Metalloporphyrins are synthetic catalytic antioxidants that mimic the body's own antioxidant enzymes i.e. superoxide dismutases and catalase. The goal of this study was to determine if newly designed metalloporphyrins have enhanced pharmacodynamics including oral bioavailability, longer plasma elimination half-lives, penetrate the blood brain barrier, and show promise for PD treatment. Three metalloporphyrins (AEOL 11216, AEOL 11203 and AEOL 11114) were identified in this study as potential candidates for further pre-clinical development. Each of these compounds demonstrated blood brain barrier permeability by the i.p. route and two of three compounds (AEOL 11203 and AEOL 11114) were orally bioavailable. All of these compounds protected against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity, including dopamine depletion in the striatum, dopaminergic neuronal loss in the substantial nigra, and increased oxidative/nitrative stress indices (glutathione disulfide and 3-nitrotyrosine) in the ventral midbrain of the mice without inhibiting MPTP metabolism. Daily therapeutic dosing of these metalloporphyrins were well tolerated without accumulation of brain manganese levels or behavioral alterations assessed by open field and rotarod tests. The study identified two orally active metalloporphyrins and one injectable metalloporphyrin as clinical candidates for further development in PD. - Highlights: • A series of metalloporphyrins were optimized in a mouse model of parkinsonism. • Two novel orally active, brain permeable antioxidant metalloporphyrins were identified. • The identified metalloporphyrins were well tolerated.

Relationship between the induction frequency and LTE in inductively coupled plasmas

International Nuclear Information System (INIS)

Mostaghimi, J.; Boulos, M.I.

1990-01-01

In this paper, the effect of the induction frequency on the local thermodynamic equilibrium (LTE) conditions in an inductively coupled plasma is investigated. Using generators with frequencies ranging from 5 to 56 MHz, a previous study investigated demonstrated the importance of this effect. Their measurements of the excitation temperatures of the iron atomic lines showed a sharp decrease in this temperature as a result of the increase in frequency. Another conclusion was that, all other parameters constant, increase in frequency will help the promotion of non-LTE effects

Identification and induction of cytochrome P450s involved in the metabolism of flavone-8-acetic acid in mice

OpenAIRE

Pham, Minh Hien; Rhinn, Hervé; Auzeil, Nicolas; Regazzetti, Anne; Harami, Djamel Eddine; Scherman, Daniel; Chabot, Guy G.

2011-01-01

The metabolism of flavone-8-acetic acid (FAA) has been hypothesized to be partly responsible for its potent anticancer activity in mice. The purpose of this study was to identify the mouse enzymes involved in FAA Phase I metabolism and evaluate their possible induction in vivo by FAA. Mouse microsomes metabolized FAA into 6 metabolites: 3′,4′-dihydrodiol-FAA, 5,6-epoxy-FAA, 4′-OH-FAA, 3′-OH-FAA, 3′,4′-epoxy-FAA and 6-OH-FAA. Using Cyp-specific inhibitors (furafylline, Cyp1a2; α-naphthoflavone...

Preclinical evaluation of radiolabeled DOTA-derivatized cyclic minigastrin analogs for targeting cholecystokinin receptor expressing malignancies.

NARCIS (Netherlands)

Guggenberg, E. von; Rangger, C.; Sosabowski, J.; Laverman, P.; Reubi, J.C.; Virgolini, I.J.; Decristoforo, C.

2012-01-01

PURPOSE: Targeting of cholecystokinin receptor expressing malignancies such as medullary thyroid carcinoma is currently limited by low in vivo stability of radioligands. To increase the stability, we have developed and preclinically evaluated two cyclic

SPECT and PET imaging of angiogenesis and arteriogenesis in pre-clinical models of myocardial ischemia and peripheral vascular disease

Energy Technology Data Exchange (ETDEWEB)

Hendrikx, Geert [Maastricht University Medical Centre MUMC+, Department of Nuclear Medicine, Postbox 5800, Maastricht (Netherlands); Maastricht University, Cardiovascular Research Institute Maastricht (CARIM), Maastricht (Netherlands); Voeoe, Stefan [Maastricht University Medical Centre MUMC+, Department of Nuclear Medicine, Postbox 5800, Maastricht (Netherlands); Bauwens, Matthias [Maastricht University Medical Centre MUMC+, Department of Nuclear Medicine, Postbox 5800, Maastricht (Netherlands); Maastricht University, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht (Netherlands); Post, Mark J. [Maastricht University, Department of Physiology, Maastricht (Netherlands); Maastricht University, Cardiovascular Research Institute Maastricht (CARIM), Maastricht (Netherlands); Mottaghy, Felix M. [Maastricht University Medical Centre MUMC+, Department of Nuclear Medicine, Postbox 5800, Maastricht (Netherlands); University Hospital, RWTH Aachen University, Department of Nuclear Medicine, Aachen (Germany)

2016-12-15

The extent of neovascularization determines the clinical outcome of coronary artery disease and other occlusive cardiovascular disorders. Monitoring of neovascularization is therefore highly important. This review article will elaborately discuss preclinical studies aimed at validating new nuclear angiogenesis and arteriogenesis tracers. Additionally, we will briefly address possible obstacles that should be considered when designing an arteriogenesis radiotracer. A structured medline search was the base of this review, which gives an overview on different radiopharmaceuticals that have been evaluated in preclinical models. Neovascularization is a collective term used to indicate different processes such as angiogenesis and arteriogenesis. However, while it is assumed that sensitive detection through nuclear imaging will facilitate translation of successful therapeutic interventions in preclinical models to the bedside, we still lack specific tracers for neovascularization imaging. Most nuclear imaging research to date has focused on angiogenesis, leaving nuclear arteriogenesis imaging largely overlooked. Although angiogenesis is the process which is best understood, there is no scarcity in theoretical targets for arteriogenesis imaging. (orig.)

Preclinical detection of porcine circovirus type 2 infection using an ultrasensitive nanoparticle DNA probe-based PCR assay.

Directory of Open Access Journals (Sweden)

Yong Huang

Full Text Available Porcine circovirus type 2 (PCV2 has emerged as one of the most important pathogens affecting swine production globally. Preclinical identification of PCV2 is very important for effective prophylaxis of PCV2-associated diseases. In this study, we developed an ultrasensitive nanoparticle DNA probe-based PCR assay (UNDP-PCR for PCV2 detection. Magnetic microparticles coated with PCV2 specific DNA probes were used to enrich PCV2 DNA from samples, then gold nanoparticles coated with PCV2 specific oligonucleotides were added to form a sandwich nucleic acid-complex. After the complex was formed, the oligonucleotides were released and characterized by PCR. This assay exhibited about 500-fold more sensitive than conventional PCR, with a detection limit of 2 copies of purified PCV2 genomic DNA and 10 viral copies of PCV2 in serum. The assay has a wide detection range for all of PCV2 genotypes with reliable reproducibility. No cross-reactivity was observed from the samples of other related viruses including porcine circovirus type 1, porcine parvovirus, porcine pseudorabies virus, porcine reproductive and respiratory syndrome virus and classical swine fever virus. The positive detection rate of PCV2 specific UNDP-PCR in 40 preclinical field samples was 27.5%, which appeared greater than that by conventional and real-time PCR and appeared application potency in evaluation of the viral loads levels of preclinical infection samples. The UNDP-PCR assay reported here can reliably rule out false negative results from antibody-based assays, provide a nucleic acid extraction free, specific, ultrasensitive, economic and rapid diagnosis method for preclinical PCV2 infection in field, which may help prevent large-scale outbreaks.

Curriculum content and assessment of pre-clinical dental skills: A survey of undergraduate dental education in Europe.

Science.gov (United States)

Field, J; Stone, S; Orsini, C; Hussain, A; Vital, S; Crothers, A; Walmsley, D

2018-05-01

Since 1981, the qualifications for various healthcare professionals across the European Union have enjoyed mutual recognition in accordance with the EU Directive 81/1057/EEC. Whilst the directive includes dental practitioners, it is recognised that significant variation exists in curriculum structure, content and scope of practice across institutions. This article aimed to explore pan-European practice in relation to curriculum content, teaching and learning strategies and assessment of pre-clinical dental skills. A request to complete an online questionnaire, in English, was sent electronically to skills leads at all Association of Dental Education in Europe member schools. The questionnaire collected information in relation to institution and country, regulatory requirements to demonstrate safety, details of specific pre-clinical skills courses, learning materials and teaching staff. Forty-eight institutions, from 25 European countries responded. Seven countries (n=7, 28%) reported no requirement to demonstrate student operative safety prior to patient treatment. Several core and operative clinical skills are common to the majority of institutions. The most commonly taught core skills related directly to the clinical environment such as cross-infection control and hand washing. The least common were skills that indirectly related to patient care, such as communication skills and working as a team. There are clear differences within European pre-clinical dental education, and greater efforts are needed to demonstrate that all European students are fit to practice before they start treating patients. Learning outcomes, teaching activities and assessment activities of pre-clinical skills should be shared collaboratively to further standardise curricula. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Autophagy-Related Deubiquitinating Enzymes Involved in Health and Disease

Directory of Open Access Journals (Sweden)

Fouzi El Magraoui

2015-10-01

Full Text Available Autophagy is an evolutionarily-conserved process that delivers diverse cytoplasmic components to the lysosomal compartment for either recycling or degradation. This involves the removal of protein aggregates, the turnover of organelles, as well as the elimination of intracellular pathogens. In this situation, when only specific cargoes should be targeted to the lysosome, the potential targets can be selectively marked by the attachment of ubiquitin in order to be recognized by autophagy-receptors. Ubiquitination plays a central role in this process, because it regulates early signaling events during the induction of autophagy and is also used as a degradation-tag on the potential autophagic cargo protein. Here, we review how the ubiquitin-dependent steps of autophagy are balanced or counteracted by deubiquitination events. Moreover, we highlight the functional role of the corresponding deubiquitinating enzymes and discuss how they might be involved in the occurrence of cancer, neurodegenerative diseases or infection with pathogenic bacteria.

An overview of technologies for immobilization of enzymes and surface analysis techniques for immobilized enzymes

Science.gov (United States)

Mohamad, Nur Royhaila; Marzuki, Nur Haziqah Che; Buang, Nor Aziah; Huyop, Fahrul; Wahab, Roswanira Abdul

2015-01-01

The current demands of sustainable green methodologies have increased the use of enzymatic technology in industrial processes. Employment of enzyme as biocatalysts offers the benefits of mild reaction conditions, biodegradability and catalytic efficiency. The harsh conditions of industrial processes, however, increase propensity of enzyme destabilization, shortening their industrial lifespan. Consequently, the technology of enzyme immobilization provides an effective means to circumvent these concerns by enhancing enzyme catalytic properties and also simplify downstream processing and improve operational stability. There are several techniques used to immobilize the enzymes onto supports which range from reversible physical adsorption and ionic linkages, to the irreversible stable covalent bonds. Such techniques produce immobilized enzymes of varying stability due to changes in the surface microenvironment and degree of multipoint attachment. Hence, it is mandatory to obtain information about the structure of the enzyme protein following interaction with the support surface as well as interactions of the enzymes with other proteins. Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes. These technologies are pertinent to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies. PMID:26019635

Enzyme inhibition by iminosugars

DEFF Research Database (Denmark)

López, Óscar; Qing, Feng-Ling; Pedersen, Christian Marcus

2013-01-01

Imino- and azasugar glycosidase inhibitors display pH dependant inhibition reflecting that both the inhibitor and the enzyme active site have groups that change protonation state with pH. With the enzyme having two acidic groups and the inhibitor one basic group, enzyme-inhibitor complexes...

Targeted enzyme prodrug therapies.

Science.gov (United States)

Schellmann, N; Deckert, P M; Bachran, D; Fuchs, H; Bachran, C

2010-09-01

The cure of cancer is still a formidable challenge in medical science. Long-known modalities including surgery, chemotherapy and radiotherapy are successful in a number of cases; however, invasive, metastasized and inaccessible tumors still pose an unresolved and ongoing problem. Targeted therapies designed to locate, detect and specifically kill tumor cells have been developed in the past three decades as an alternative to treat troublesome cancers. Most of these therapies are either based on antibody-dependent cellular cytotoxicity, targeted delivery of cytotoxic drugs or tumor site-specific activation of prodrugs. The latter is a two-step procedure. In the first step, a selected enzyme is accumulated in the tumor by guiding the enzyme or its gene to the neoplastic cells. In the second step, a harmless prodrug is applied and specifically converted by this enzyme into a cytotoxic drug only at the tumor site. A number of targeting systems, enzymes and prodrugs were investigated and improved since the concept was first envisioned in 1974. This review presents a concise overview on the history and latest developments in targeted therapies for cancer treatment. We cover the relevant technologies such as antibody-directed enzyme prodrug therapy (ADEPT), gene-directed enzyme prodrug therapy (GDEPT) as well as related therapies such as clostridial- (CDEPT) and polymer-directed enzyme prodrug therapy (PDEPT) with emphasis on prodrug-converting enzymes, prodrugs and drugs.

Learning style preferences among pre-clinical medical students

Directory of Open Access Journals (Sweden)

Aye Aye Mon

2014-02-01

Full Text Available Generally, different students employ different learning styles dur-ing their studies and medical students are exposed to diverse methods of teaching. Therefore, understanding students’ learning style preference is an important consideration for a high quality and effective teaching and learning process.The aim of the study was to study the variation of learning styles among pre-clinical medical students of SEGi University, Malaysia. A cross-sectional study was performed by using VARK (Visual, Audio, Reading and Kinaesthetic questionnaire version 7.2 to assess the learning style preference of 98 (n=98 pre-clinical medical students in SEGi University. The questionnaire consists of 16 items which identify four different learning styles: visual, aural, reading/writing and kin-esthetic. Descriptive statistics were used to identify the learning styles of students. 61 students preferred multimodal as their learning style, out of which 43 (70% of them were female stu-dents and 18 (30% were male students. 37 students preferred unimodal as their learning style out of which 22 (59% of them were female students and 15 (41% were male students. In addi-tion, female students had more diverse preferences than male students by having 10 out of the other 11 possible combinations in multimodal learning style of preference, whereas the male stu-dents only had 5 out of the 11 combinations. In this study, there was no significant gender difference in the percentages of males and female students who preferred unimodal and multimodal styles of information presentation (P= 0.263; α=0.05. To con-clude, the majority of students of both genders had chosen quad-modal as their learning style preference. The results of this study can provide useful information for improving the quality of the teaching and learning experiences of students.

Quality Induction: The Effects of Comprehensive Induction on New Teacher Retention and Job Satisfaction

Science.gov (United States)

Hendricks-Harris, Mary Therese

2012-01-01

This investigation examined the effect of a comprehensive new teacher induction program on teacher retention and job satisfaction in one suburban school district. New teachers are retained at low rates, and districts are spending resources in an attempt to decrease this number. New teacher induction includes supports for new teachers in their…

78 FR 70307 - Guidance for Industry: Preclinical Assessment of Investigational Cellular and Gene Therapy...

Science.gov (United States)

2013-11-25

...] Guidance for Industry: Preclinical Assessment of Investigational Cellular and Gene Therapy Products... Assessment of Investigational Cellular and Gene Therapy Products'' dated November 2013. The guidance document... products reviewed by the Office of Cellular, Tissue and Gene Therapies (OCTGT). The product areas covered...

Enzyme-MOF (metal-organic framework) composites.

Science.gov (United States)

Lian, Xizhen; Fang, Yu; Joseph, Elizabeth; Wang, Qi; Li, Jialuo; Banerjee, Sayan; Lollar, Christina; Wang, Xuan; Zhou, Hong-Cai

2017-06-06

The ex vivo application of enzymes in various processes, especially via enzyme immobilization techniques, has been extensively studied in recent years in order to enhance the recyclability of enzymes, to minimize enzyme contamination in the product, and to explore novel horizons for enzymes in biomedical applications. Possessing remarkable amenability in structural design of the frameworks as well as almost unparalelled surface tunability, Metal-Organic Frameworks (MOFs) have been gaining popularity as candidates for enzyme immobilization platforms. Many MOF-enzyme composites have achieved unprecedented results, far outperforming free enzymes in many aspects. This review summarizes recent developments of MOF-enzyme composites with special emphasis on preparative techniques and the synergistic effects of enzymes and MOFs. The applications of MOF-enzyme composites, primarily in transferation, catalysis and sensing, are presented as well. The enhancement of enzymatic activity of the composites over free enzymes in biologically incompatible conditions is emphasized in many cases.

Artificial Inductance Concept to Compensate Nonlinear Inductance Effects in the Back EMF-Based Sensorless Control Method for PMSM

DEFF Research Database (Denmark)

Lu, Kaiyuan; Lei, Xiao; Blaabjerg, Frede

2013-01-01

The back EMF-based sensorless control method is very popular for permanent magnet synchronous machines (PMSMs) in the medium- to high-speed operation range due to its simple structure. In this speed range, the accuracy of the estimated position is mainly affected by the inductance, which varies...... at different loading conditions due to saturation effects. In this paper, a new concept of using a constant artificial inductance to replace the actual varying machine inductance for position estimation is introduced. This facilitates greatly the analysis of the influence of inductance variation...

Plasma internal inductance dynamics in a tokamak

International Nuclear Information System (INIS)

Romero, J.A.

2010-01-01

A lumped parameter model for tokamak plasma current and inductance time evolution as a function of plasma resistance, non-inductive current drive sources and boundary voltage or poloidal field coil current drive is presented. The model includes a novel formulation leading to exact equations for internal inductance and plasma current dynamics. Having in mind its application in a tokamak inductive control system, the model is expressed in state space form, the preferred choice for the design of control systems using modern control systems theory. The choice of system states allows many interesting physical quantities such as plasma current, inductance, magnetic energy, and resistive and inductive fluxes be made available as output equations. The model is derived from energy conservation theorem, and flux balance theorems, together with a first order approximation for flux diffusion dynamics. The validity of this approximation has been checked using experimental data from JET showing an excellent agreement.

Exploratory study of factors related to educational scores of first preclinical year medical students.

Science.gov (United States)

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

2014-03-01

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. Questionnaires were sent out to all first preclinical year medical students, with 79.8% being returned (245/307 questionnaires). Positive correlations were revealed between the premedical year grade point average (pre-MD GPA) and anatomy, physiology, and biochemistry scores (R = 0.664, 0.521, and 0.653, respectively, P student satisfaction with anatomy, the percentage of expected reading, monthly earnings, reading after class and near exam time, and duration of sleeping periods near exam time (R = 0.773, R(2) = 0.598, P student satisfaction with biochemistry, and exam performance expectations (R = 0.794, R(2) = 0.630, P satisfaction.

Preclinical evaluations of norcantharidin-loaded intravenous lipid microspheres with low toxicity.

Science.gov (United States)

Lin, Xia; Zhang, Bo; Zhang, Keru; Zhang, Yu; Wang, Juan; Qi, Na; Yang, Shenshen; He, Haibing; Tang, Xing

2012-12-01

The aim of this study was to perform a systematic preclinical evaluation of norcantharidin (NCTD)-loaded intravenous lipid microspheres (NLM). Pharmacokinetics, biodistribution, antitumor efficacy and drug safety assessment (including acute toxicity, subchronic toxicity, hemolysis testing, intravenous stimulation and injection anaphylaxis) of NLM were carried out in comparison with the commercial product disodium norcantharidate injection (NI). The pharmacokinetics of NLM in rats was similar to that of NI, and a non-linear correlation was observed between AUC and dose. A comparable antitumor efficacy of NLM and NI was observed in mice inoculated with A549, BEL7402 and BCAP-37 cell lines. It was worth noting that the NLM produced a lower drug concentration in heart compared with NI, and significantly reduced the cardiac and renal toxicity. The LD(50) of NLM was twice higher than that of NI. In NLM, over 80% of NCTD was loaded in the lipid phase or bound with phospholipids. Thus, NCTD was sequestered by direct contacting with body fluids and largely avoided distribution into tissues, consequently leading to significantly reduced cardiac and renal toxicity. These preclinical results suggested that NLM could be a useful potential carrier for parenteral administration of NCTD, while providing a superior safety profile.

Kinetic and structural evidences on human prolidase pathological mutants suggest strategies for enzyme functional rescue.

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Roberta Besio

Full Text Available Prolidase is the only human enzyme responsible for the digestion of iminodipeptides containing proline or hydroxyproline at their C-terminal end, being a key player in extracellular matrix remodeling. Prolidase deficiency (PD is an intractable loss of function disease, characterized by mutations in the prolidase gene. The exact causes of activity impairment in mutant prolidase are still unknown. We generated three recombinant prolidase forms, hRecProl-231delY, hRecProl-E412K and hRecProl-G448R, reproducing three mutations identified in homozygous PD patients. The enzymes showed very low catalytic efficiency, thermal instability and changes in protein conformation. No variation of Mn(II cofactor affinity was detected for hRecProl-E412K; a compromised ability to bind the cofactor was found in hRecProl-231delY and Mn(II was totally absent in hRecProl-G448R. Furthermore, local structure perturbations for all three mutants were predicted by in silico analysis. Our biochemical investigation of the three causative alleles identified in perturbed folding/instability, and in consequent partial prolidase degradation, the main reasons for enzyme inactivity. Based on the above considerations we were able to rescue part of the prolidase activity in patients' fibroblasts through the induction of Heath Shock Proteins expression, hinting at new promising avenues for PD treatment.

Probabilistic inductive inference: a survey

OpenAIRE

Ambainis, Andris

2001-01-01

Inductive inference is a recursion-theoretic theory of learning, first developed by E. M. Gold (1967). This paper surveys developments in probabilistic inductive inference. We mainly focus on finite inference of recursive functions, since this simple paradigm has produced the most interesting (and most complex) results.

An economic evaluation of preclinical testing strategies compared to the compulsory scrapie flock scheme in the control of classical scrapie.

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Lisa Boden

Full Text Available Cost-benefit is rarely combined with nonlinear dynamic models when evaluating control options for infectious diseases. The current strategy for scrapie in Great Britain requires that all genetically susceptible livestock in affected flocks be culled (Compulsory Scrapie Flock Scheme or CSFS. However, this results in the removal of many healthy sheep, and a recently developed pre-clinical test for scrapie now offers a strategy based on disease detection. We explore the flock level cost-effectiveness of scrapie control using a deterministic transmission model and industry estimates of costs associated with genotype testing, pre-clinical tests and the value of a sheep culled. Benefit was measured in terms of the reduction in the number of infected sheep sold on, compared to a baseline strategy of doing nothing, using Incremental Cost Effectiveness analysis to compare across strategies. As market data was not available for pre-clinical testing, a threshold analysis was used to set a unit-cost giving equal costs for CSFS and multiple pre-clinical testing (MT, one test each year for three consecutive years. Assuming a 40% within-flock proportion of susceptible genotypes and a test sensitivity of 90%, a single test (ST was cheaper but less effective than either the CSFS or MT strategies (30 infected-sales-averted over the lifetime of the average epidemic. The MT strategy was slightly less effective than the CSFS and would be a dominated strategy unless preclinical testing was cheaper than the threshold price of £6.28, but may be appropriate for flocks with particularly valuable livestock. Though the ST is not currently recommended, the proportion of susceptible genotypes in the national flock is likely to continue to decrease; this may eventually make it a cost-effective alternative to the MT or CSFS.

Nonylphenol-mediated CYP induction is PXR-dependent: The use of humanized mice and human hepatocytes suggests that hPXR is less sensitive than mouse PXR to nonylphenol treatment

International Nuclear Information System (INIS)

Mota, Linda C.; Barfield, Christina; Hernandez, Juan P.; Baldwin, William S.

2011-01-01