Characteristics of the uridine uptake system in normal and polyoma transformed hamster embryo cells

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

Lemkin, J.A.

1973-01-01

The lability of the uridine uptake system in the normal and polyoma transformed hamster embryo fibroblast was studied. The major areas investigated were: the kinetic parameters of uridine transport, a comparison of changes in cellular ATP content by factors which modulate uridine uptake, and a comparison of the qualitative and quantitative effects of the same modulating agent on uridine transport, cell growth, and cellular ATP content. Uridine uptake into cells in vitro was examined using tritiated uridine as a tracer to measure the amount of uridine incorporated into the acid soluble and acid-insoluble fractions of the cells studied. The ATPmore » content of the cells was determined by the firefly bioluminescence method. It was found that the K/sub t/ for uridine uptake into the normal hamster embryo cell and two polyoma transformed hamster embryo cell lines was identical. However, the V/sub max/ for uridine transport was higher in both polyoma transformed cell lines. Furthermore, the K/sub t/ in both the normal and transformed cell cultured in serum-less or serum-containing media was identical, although the V/sub max/ was higher in the serum-stimulated cell in both the normal and transformed cell. Stimulation of the normal cell with adenosine produced a different K/sub t/ for uridine transport. Preliminary investigations have demonstrated that treatment of the polyoma transformed with adenosine also induces a different K/sub t/ (not shown). The K/sub i/ for phloretin inhibition in serum-less and serum-stimulated normal and polyoma transformed cells was found to be identical in each case.« less

Homologous Recombination Repair Protects Against Particulate Chromate-induced Chromosome Instability in Chinese Hamster Cells

PubMed Central

Stackpole, Megan M.; Wise, Sandra S.; Duzevik, Eliza Grlickova; Munroe, Ray C.; Thompson, W. Douglas; Thacker, John; Thompson, Larry H.; Hinz, John M.; Wise, John Pierce

2008-01-01

Particulate hexavalent chromium [Cr(VI)] compounds are well-established human carcinogens. Cr(VI)-induced tumors are characterized by chromosomal instability (CIN); however, the mechanisms of this effect are unknown. We investigated the hypothesis that homologous recombination (HR) repair of DNA double strand breaks protect cells from Cr(VI)-induced CIN by focusing on the XRCC3 and RAD51C genes, which play an important role in cellular resistance to DNA double strand breaks. We used Chinese hamster cells defective in each HR gene (irs3 for RAD51C and irs1SF for XRCC3) and compared with their wildtype parental and cDNA-complemented controls. We found that the intracellular Cr ion levels varied among the cell lines after particulate chromate treatment. Importantly, accounting for differences in Cr ion levels, we discovered that XRCC3 and RAD51C cells treated with lead chromate had increased cytotoxicity and chromosomal aberrations, relative to wild-type and cDNA-complimented cells. We also observed the emergence of high levels of chromatid exchanges in the two mutant cell lines. For example, 1 ug/cm2 lead chromate induced 20 and 32 exchanges in XRCC3- and RAD51C-deficient cells, respectively, whereas no exchanges were detected in the wildtype and cDNA-complemented cells. These observations suggest that HR protects cells from Cr(VI)-induced CIN, consistent with the ability of particulate Cr(VI) to induce double strand breaks. PMID:17662313

Transformation of Primary Hamster Brain Cells with JC Virus and Its DNA

PubMed Central

Frisque, R. J.; Rifkin, D. B.; Walker, D. L.

1980-01-01

We transformed primary hamster brain cells with four isolates of JC virus and JC virus DNA. Several properties of these transformants were characterized and compared to those of simian virus 40 transformants isolated under identical conditions. Images PMID:6251275

Crocidolite asbestos and SV40 are cocarcinogens in human mesothelial cells and in causing mesothelioma in hamsters

PubMed Central

Kroczynska, Barbara; Cutrone, Rochelle; Bocchetta, Maurizio; Yang, Haining; Elmishad, Amira G.; Vacek, Pamela; Ramos-Nino, Maria; Mossman, Brooke T.; Pass, Harvey I.; Carbone, Michele

2006-01-01

Only a fraction of subjects exposed to asbestos develop malignant mesothelioma (MM), suggesting that additional factors may render some individuals more susceptible. We tested the hypothesis that asbestos and Simian virus (SV40) are cocarcinogens. Asbestos and SV40 in combination had a costimulatory effect in inducing ERK1/2 phosphorylation and activator protein-1 (AP-1) activity in both primary Syrian hamster mesothelial cells (SHM) and primary human mesothelial cells (HM). Ap-1 activity caused the expression and activation of matrix metalloprotease (MMP)-1 and MMP-9, which in turn led to cell invasion. Experiments using siRNA and chemical inhibitors confirmed the specificity of these results. The same effects were observed in HM and SHM. Experiments in hamsters showed strong cocarcinogenesis between asbestos and SV40: SV40 did not cause MM, asbestos caused MM in 20% of hamsters, and asbestos and SV40 together caused MM in 90% of hamsters. Significantly lower amounts of asbestos were sufficient to cause MM in animals infected with SV40. Our results indicate that mineral fibers and viruses can be cocarcinogens and suggest that lower amounts of asbestos may be sufficient to cause MM in individuals infected with SV40. PMID:16966607

The Saccharomyces cerevisiae DPM1 gene encoding dolichol-phosphate-mannose synthase is able to complement a glycosylation-defective mammalian cell line.

PubMed Central

Beck, P J; Orlean, P; Albright, C; Robbins, P W; Gething, M J; Sambrook, J F

1990-01-01

The Saccharomyces cerevisiae DPM1 gene product, dolichol-phosphate-mannose (Dol-P-Man) synthase, is involved in the coupled processes of synthesis and membrane translocation of Dol-P-Man. Dol-P-Man is the lipid-linked sugar donor of the last four mannose residues that are added to the core oligosaccharide transferred to protein during N-linked glycosylation in the endoplasmic reticulum. We present evidence that the S. cerevisiae gene DPM1, when stably transfected into a mutant Chinese hamster ovary cell line, B4-2-1, is able to correct the glycosylation defect of the cells. Evidence for complementation includes (i) fluorescence-activated cell sorter analysis of differential lectin binding to cell surface glycoproteins, (ii) restoration of Dol-P-Man synthase enzymatic activity in crude cell lysates, (iii) isolation and high-performance liquid chromatography fractionation of the lipid-linked oligosaccharides synthesized in the transfected and control cell lines, and (iv) the restoration of endoglycosidase H sensitivity to the oligosaccharides transferred to a specific glycoprotein synthesized in the DPM1 CHO transfectants. Indirect immunofluorescence with a primary antibody directed against the DPM1 protein shows a reticular staining pattern of protein localization in transfected hamster and monkey cell lines. Images PMID:2201896

Synergetic cholesterol-lowering effects of main alkaloids from Rhizoma Coptidis in HepG2 cells and hypercholesterolemia hamsters.

PubMed

Kou, Shuming; Han, Bing; Wang, Yue; Huang, Tao; He, Kai; Han, Yulong; Zhou, Xia; Ye, Xiaoli; Li, Xuegang

2016-04-15

Hyperlipidemia contributes to the progression of cardiovascular diseases. Main alkaloids from Rhizoma Coptidis including berberine (BBR), coptisine (COP), palmatine (PAL), epiberberine (EPI) and jatrorrhizine (JAT), improved dyslipidemia in hypercholesterolemic hamsters to a different degree. In this study, HepG2 cells and hypercholesterolemic hamsters were used to investigate the synergetic cholesterol-lowering efficacy of these five main alkaloids. The cellular lipid and cholesterol accumulation and in HepG2 cells were evaluated by Oil Red O staining and HPLC analysis. LDL receptor, 3-Hydroxy-3-methylglutaryl CoA reductase (HMGCR) and cholesterol 7-alpha-hydroxylase (CYP7A1) that involving cholesterol metabolism in HepG2 cells were measured by qRT-PCR, western blot and immunofluorescence analysis. The serum profiles including total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-c) and high-density lipoprotein cholesterol (HDL-c), as well as TC and total bile acids (TBA) of feces in hypercholesterolemic hamsters were also measured. As compared to single alkaloids, the combination of five main alkaloids (COM) reduced the lipid and cholesterol accumulation in HepG2 cells more effectively and performed an advantageous effect on controlling TC, TG, LDL-c and HDL-c in hypercholesterolemic hamsters. More effective reduction of TBA and TC levels in feces of hamsters were achieved after the administration of COM. These effects were derived from the up-regulation of LDL receptor and CYP7A1, as well as HMGCR downregulation. Our results demonstrated that COM showed a synergetic cholesterol-lowering efficacy, which was better than single alkaloids and it might be considered as a potential therapy for hypercholesterolemia. Copyright © 2016 Elsevier Inc. All rights reserved.

p48 Activates a UV-Damaged-DNA Binding Factor and Is Defective in Xeroderma Pigmentosum Group E Cells That Lack Binding Activity

PubMed Central

Hwang, Byung Joon; Toering, Stephanie; Francke, Uta; Chu, Gilbert

1998-01-01

A subset of xeroderma pigmentosum (XP) group E cells lack a factor that binds to DNA damaged by UV radiation. This factor can be purified to homogeneity as p125, a 125-kDa polypeptide. However, when cDNA encoding p125 is translated in vitro, only a small fraction binds to UV-damaged DNA, suggesting that a second factor is required for the activation of p125. We discovered that most hamster cell lines expressed inactive p125, which was activated in somatic cell hybrids containing human chromosome region 11p11.2-11cen. This region excluded p125 but included p48, which encodes a 48-kDa polypeptide known to copurify with p125 under some conditions. Expression of human p48 activated p125 binding in hamster cells and increased p125 binding in human cells. No such effects were observed from expression of p48 containing single amino acid substitutions from XP group E cells that lacked binding activity, demonstrating that the p48 gene is defective in those cells. Activation of p125 occurred by a “hit-and-run” mechanism, since the presence of p48 was not required for subsequent binding. Nevertheless, p48 was capable of forming a complex with p125 either bound to UV-damaged DNA or in free solution. It is notable that hamster cells fail to efficiently repair cyclobutane pyrimidine dimers in nontranscribed DNA and fail to express p48, which contains a WD motif with homology to proteins that reorganize chromatin. We propose that p48 plays a role in repairing lesions that would otherwise remain inaccessible in nontranscribed chromatin. PMID:9632823

Inhibitory effect of vitamin D-binding protein-derived macrophage activating factor on DMBA-induced hamster cheek pouch carcinogenesis and its derived carcinoma cell line.

PubMed

Toyohara, Yukiyo; Hashitani, Susumu; Kishimoto, Hiromitsu; Noguchi, Kazuma; Yamamoto, Nobuto; Urade, Masahiro

2011-07-01

This study investigated the inhibitory effect of vitamin D-binding protein-derived macrophage-activating factor (GcMAF) on carcinogenesis and tumor growth, using a 9,10-dimethyl-1,2-benzanthracene (DMBA)-induced hamster cheek pouch carcinogenesis model, as well as the cytocidal effect of activated macrophages against HCPC-1, a cell line established from DMBA-induced cheek pouch carcinoma. DMBA application induced squamous cell carcinoma in all 15 hamsters of the control group at approximately 10 weeks, and all 15 hamsters died of tumor burden within 20 weeks. By contrast, 2 out of the 14 hamsters with GcMAF administration did not develop tumors and the remaining 12 hamsters showed a significant delay of tumor development for approximately 3.5 weeks. The growth of tumors formed was significantly suppressed and none of the hamsters died within the 20 weeks during which they were observed. When GcMAF administration was stopped at the 13th week of the experiment in 4 out of the 14 hamsters in the GcMAF-treated group, tumor growth was promoted, but none of the mice died within the 20-week period. On the other hand, when GcMAF administration was commenced after the 13th week in 5 out of the 15 hamsters in the control group, tumor growth was slightly suppressed and all 15 hamsters died of tumor burden. However, the mean survival time was significantly extended. GcMAF treatment activated peritoneal macrophages in vitro and in vivo, and these activated macrophages exhibited a marked cytocidal effect on HCPC-1 cells. Furthermore, the cytocidal effect of activated macrophages was enhanced by the addition of tumor-bearing hamster serum. These findings indicated that GcMAF possesses an inhibitory effect on tumor development and growth in a DMBA-induced hamster cheek pouch carcinogenesis model.

Inhibitory effect of vitamin D-binding protein-derived macrophage activating factor on DMBA-induced hamster cheek pouch carcinogenesis and its derived carcinoma cell line

PubMed Central

TOYOHARA, YUKIYO; HASHITANI, SUSUMU; KISHIMOTO, HIROMITSU; NOGUCHI, KAZUMA; YAMAMOTO, NOBUTO; URADE, MASAHIRO

2011-01-01

This study investigated the inhibitory effect of vitamin D-binding protein-derived macrophage-activating factor (GcMAF) on carcinogenesis and tumor growth, using a 9,10-dimethyl-1,2-benzanthracene (DMBA)-induced hamster cheek pouch carcinogenesis model, as well as the cytocidal effect of activated macrophages against HCPC-1, a cell line established from DMBA-induced cheek pouch carcinoma. DMBA application induced squamous cell carcinoma in all 15 hamsters of the control group at approximately 10 weeks, and all 15 hamsters died of tumor burden within 20 weeks. By contrast, 2 out of the 14 hamsters with GcMAF administration did not develop tumors and the remaining 12 hamsters showed a significant delay of tumor development for approximately 3.5 weeks. The growth of tumors formed was significantly suppressed and none of the hamsters died within the 20 weeks during which they were observed. When GcMAF administration was stopped at the 13th week of the experiment in 4 out of the 14 hamsters in the GcMAF-treated group, tumor growth was promoted, but none of the mice died within the 20-week period. On the other hand, when GcMAF administration was commenced after the 13th week in 5 out of the 15 hamsters in the control group, tumor growth was slightly suppressed and all 15 hamsters died of tumor burden. However, the mean survival time was significantly extended. GcMAF treatment activated peritoneal macrophages in vitro and in vivo, and these activated macrophages exhibited a marked cytocidal effect on HCPC-1 cells. Furthermore, the cytocidal effect of activated macrophages was enhanced by the addition of tumor-bearing hamster serum. These findings indicated that GcMAF possesses an inhibitory effect on tumor development and growth in a DMBA-induced hamster cheek pouch carcinogenesis model. PMID:22848250

Hematologic Assessment in Pet Rats, Mice, Hamsters, and Gerbils: Blood Sample Collection and Blood Cell Identification.

PubMed

Lindstrom, Nicole M; Moore, David M; Zimmerman, Kurt; Smith, Stephen A

2015-09-01

Hamsters, gerbils, rats, and mice are presented to veterinary clinics and hospitals for prophylactic care and treatment of clinical signs of disease. Physical examination, history, and husbandry practice information can be supplemented greatly by assessment of hematologic parameters. As a resource for veterinarians and their technicians, this article describes the methods for collection of blood, identification of blood cells, and interpretation of the hemogram in mice, rats, gerbils, and hamsters. Copyright © 2015 Elsevier Inc. All rights reserved.

Large-Scale Transient Transfection of Chinese Hamster Ovary Cells in Suspension.

PubMed

Rajendra, Yashas; Balasubramanian, Sowmya; Hacker, David L

2017-01-01

We describe a one-liter transfection of suspension-adapted Chinese hamster ovary (CHO-DG44) cells using polyethyleneimine (PEI) for DNA delivery. The method involves transfection at a high cell density (5 × 10 6 cells/mL) by direct addition of plasmid DNA (pDNA) and PEI to the culture and subsequent incubation at 31 °C with agitation by orbital shaking. We also describe an alternative method in which 90% of the pDNA is replaced by nonspecific (filler) DNA, and the production phase is performed at 31 °C in the presence of 0.25% N, N-dimethylacetamide (DMA).

Isolation and characterization of a Chinese hamster ovary cell mutant with altered regulation of phosphatidylserine biosynthesis

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

Hasegawa, K.; Kuge, O.; Nishijima, M.

1989-11-25

We have screened approximately 10,000 colonies of Chinese hamster ovary (CHO) cells immobilized on polyester cloth for mutants defective in (14C)ethanolamine incorporation into trichloroacetic acid-precipitable phospholipids. In mutant 29, discovered in this way, the activities of enzymes involved in the CDP-ethanolamine pathway were normal; however, the intracellular pool of phosphorylethanolamine was elevated, being more than 10-fold that in the parental CHO-K1 cells. These results suggested that the reduced incorporation of (14C)ethanolamine into phosphatidylethanolamine in mutant 29 was due to dilution of phosphoryl-(14C)ethanolamine with the increased amount of cellular phosphorylethanolamine. Interestingly, the rate of incorporation of serine into phosphatidylserine and themore » content of phosphatidylserine in mutant 29 cells were increased 3-fold and 1.5-fold, respectively, compared with the parent cells. The overproduction of phosphorylethanolamine in mutant 29 cells was ascribed to the elevated level of phosphatidylserine biosynthesis, because ethanolamine is produced as a reaction product on the conversion of phosphatidylethanolamine to phosphatidylserine, which is catalyzed by phospholipid-serine base-exchange enzymes. Using both intact cells and the particulate fraction of a cell extract, phosphatidylserine biosynthesis in CHO-K1 cells was shown to be inhibited by phosphatidylserine itself, whereas that in mutant 29 cells was greatly resistant to the inhibition, compared with the parental cells. As a conclusion, it may be assumed that mutant 29 cells have a lesion in the regulation of phosphatidylserine biosynthesis by serine-exchange enzyme activity, which results in the overproduction of phosphatidylserine and phosphorylethanolamine as well.« less

Mechanisms underlying radiosensitivity : iIvestigations in xrs-5, an X-ray sensitive hamster cell line

NASA Astrophysics Data System (ADS)

Johnston, Peter James

The damage caused to cells by ionising radiation is believed to center on damage to the DNA. In particular, the induction of DNA double strand breaks (DSB) have been implicated in biological end-points such as cell killing and the formation of chromosomal aberrations. The xrs-5 cell line is a mutant Chinese hamster ovary fibroblast (CHO-K1) mutant which exhibits sensitivity to ionising radiation and a number of other DNA damaging agents. This mutation, postulated to involve the hamster homologue of the human XRCC5 gene, is believed to be involved in the repair of the DSB. In addition, there are constitutive differences between the wild type and xrs cells involving the structure and function of the nucleus and higher order chromatin structures. The aims of this thesis were to study further the xrs-5 cell line and its response to DNA damage and to investigate the possible link between chromatin structure and DSB repair. By the examination of the response of xrs-5 cells to a number of DNA damaging agents and potential modulators of this response using the cytokinesis block micronucleus assay [Fenech and Morley, 1985] a possible cell cycle defect was identified in addition to elevated levels of chromosomal damage. Xrs-5 cells appeared to be partially defective in the cell cycle checkpoints involving the passage from G2 phase to mitosis. By the use of a modified neutral filter elution procedure variations in the repair of DSB were observed between xrs-5 and CHO. Conventional neutral filter elution requires harsh lysis conditions to remove higher order chromatin structures which interfere with the elution of DNA containing DSB. By lysing cells with non-ionic detergent in the presence of 2 M NaC1, histone depleted structures which retain the higher order nuclear matrix organisation, including chromatin loops, can be produced. Elution from these structures will only occur if two or more DSB lie within a single looped domain delineated by points of attachment to the nuclear

Phosphatidylserine biosynthesis in cultured Chinese hamster ovary cells. III. Genetic evidence for utilization of phosphatidylcholine and phosphatidylethanolamine as precursors

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

Kuge, O.; Nishijima, M.; Akamatsu, Y.

1986-05-05

We reported that Chinese hamster ovary (CHO) cells contain two different serine-exchange enzymes (I and II) which catalyze the base-exchange reaction of phospholipid(s) with serine and that a phosphatidylserine-requiring mutant (strain PSA-3) of CHO cells is defective in serine-exchange enzyme I and lacks the ability to synthesize phosphatidylserine. In this study, we examined precursor phospholipids for phosphatidylserine biosynthesis in CHO cells. When mutant PSA-3 and parent (CHO-K1) cells were cultured with (/sup 32/P)phosphatidylcholine, phosphatidylserine in the parent accumulated radioactivity while that in the mutant was not labeled significantly. On the contrary, when cultured with (/sup 32/P)phosphatidylethanolamine, the mutant incorporated themore » label into phosphatidylserine more efficiently than the parent. Furthermore, we found that mutant PSA-3 grew normally in growth medium supplemented with 30 microM phosphatidylethanolamine as well as phosphatidylserine and that the biosynthesis of phosphatidylserine in the mutant was normal when cells were cultured in the presence of exogenous phosphatidylethanolamine. The simplest interpretation of these findings is that phosphatidylserine in CHO cells is biosynthesized through the following sequential reactions: phosphatidylcholine----phosphatidylserine----phosphatidylethanolamine--- - phosphatidylserine. The three reactions are catalyzed by serine-exchange enzyme I, phosphatidylserine decarboxylase, and serine-exchange enzyme II, respectively.« less

Metabolic design of macroscopic bioreaction models: application to Chinese hamster ovary cells.

PubMed

Provost, A; Bastin, G; Agathos, S N; Schneider, Y-J

2006-12-01

The aim of this paper is to present a systematic methodology to design macroscopic bioreaction models for cell cultures based upon metabolic networks. The cell culture is seen as a succession of phases. During each phase, a metabolic network represents the set of reactions occurring in the cell. Then, through the use of the elementary flux modes, these metabolic networks are used to derive macroscopic bioreactions linking the extracellular substrates and products. On this basis, as many separate models are obtained as there are phases. Then, a complete model is obtained by smoothly switching from model to model. This is illustrated with batch cultures of Chinese hamster ovary cells.

Etiology of Tetracycline-Associated Pseudomembranous Colitis in Hamsters

PubMed Central

Toshniwal, Renu; Fekety, Robert; Silva, Joseph

1979-01-01

Tetracyclines were implicated in the 1950s in induction of protracted diarrhea and pseudomembranous colitis. Because the pathogenetic mechanism of these illnesses has been questioned recently, we studied tetracycline in hamster models of antibiotic-associated colitis. Orogastric administration of tetracycline caused diarrhea and death, with evidence of hemorrhagic typhlitis. Filtrates of cecal contents were toxic when inoculated into normal hamsters and cell culture monolayers, and toxicity was neutralized with Clostridium sordellii antitoxin. Tetracycline-resistant C. difficile was cultured from stools of these hamsters, but Staphylococcus aureus was not isolated. The value of tetracycline for treatment or prevention of clindamycin-induced colitis in hamsters was also studied, and it was found that daily orogastric administration of tetracycline was poorly protective against clindamycin-induced colitis. PMID:485127

Model-based analysis of N-glycosylation in Chinese hamster ovary cells

PubMed Central

Krambeck, Frederick J.; Bennun, Sandra V.; Betenbaugh, Michael J.

2017-01-01

The Chinese hamster ovary (CHO) cell is the gold standard for manufacturing of glycosylated recombinant proteins for production of biotherapeutics. The similarity of its glycosylation patterns to the human versions enable the products of this cell line favorable pharmacokinetic properties and lower likelihood of causing immunogenic responses. Because glycan structures are the product of the concerted action of intracellular enzymes, it is difficult to predict a priori how the effects of genetic manipulations alter glycan structures of cells and therapeutic properties. For that reason, quantitative models able to predict glycosylation have emerged as promising tools to deal with the complexity of glycosylation processing. For example, an earlier version of the same model used in this study was used by others to successfully predict changes in enzyme activities that could produce a desired change in glycan structure. In this study we utilize an updated version of this model to provide a comprehensive analysis of N-glycosylation in ten Chinese hamster ovary (CHO) cell lines that include a wild type parent and nine mutants of CHO, through interpretation of previously published mass spectrometry data. The updated N-glycosylation mathematical model contains up to 50,605 glycan structures. Adjusting the enzyme activities in this model to match N-glycan mass spectra produces detailed predictions of the glycosylation process, enzyme activity profiles and complete glycosylation profiles of each of the cell lines. These profiles are consistent with biochemical and genetic data reported previously. The model-based results also predict glycosylation features of the cell lines not previously published, indicating more complex changes in glycosylation enzyme activities than just those resulting directly from gene mutations. The model predicts that the CHO cell lines possess regulatory mechanisms that allow them to adjust glycosylation enzyme activities to mitigate side effects of

Effect of ambient temperature on the proliferation of brown adipocyte progenitors and endothelial cells during postnatal BAT development in Syrian hamsters.

PubMed

Nagaya, Kazuki; Okamatsu-Ogura, Yuko; Nio-Kobayashi, Junko; Nakagiri, Shohei; Tsubota, Ayumi; Kimura, Kazuhiro

2018-04-02

In Syrian hamsters, brown adipose tissue (BAT) develops postnatally through the proliferation and differentiation of brown adipocyte progenitors. In the study reported here, we investigated how ambient temperature influenced BAT formation in neonatal hamsters. In both hamsters raised at 23 or 30 °C, the interscapular fat changed from white to brown coloration in an age-dependent manner and acquired the typical morphological features of BAT by day 16. However, the expression of uncoupling protein 1, a brown adipocyte marker, and of vascular endothelial growth factor α were lower in the group raised at 30 °C than in that raised at 23 °C. Immunofluorescent staining revealed that the proportion of Ki67-expressing progenitors and endothelial cells was lower in the 30 °C group than in the 23 °C group. These results indicate that warm ambient temperature suppresses the proliferation of brown adipocyte progenitors and endothelial cells and negatively affects the postnatal development of BAT in Syrian hamsters.

CELLULAR TOXICITY IN CHINESE HAMSTER OVARY CELL CULTURES. 1. ANALYSIS OF CYTOTOXICITY ENDPOINTS FOR TWENTY-NINE PRIORITY POLLUTANTS

EPA Science Inventory

Chinese hamster ovary cells were exposed to 29 toxic chemical substances which were representative of several classes of compounds listed by the Natural Resources Defense Council Consent Decree as priority toxic pollutants. After cell cultures were exposed to the test substance, ...

Neoplastic transformation of hamster embryo cells by heavy ions

NASA Astrophysics Data System (ADS)

Han, Z.; Suzuki, H.; Suzuki, F.; Suzuki, M.; Furusawa, Y.; Kato, T.; Ikenaga, M.

1998-11-01

We have studied the induction of morphological transformation of Syrian hamster embryo cells by low doses of heavy ions with different linear energy transfer (LET), ranging from 13 to 400 keV/μm. Exponentially growing cells were irradiated with 12C or 28Si ion beams generated by the Heavy Ion Medical Accelerator in Chiba (HIMAC), inoculated to culture dishes, and transformed colonies were identified when the cells were densely stacked and showed a crisscross pattern. Over the LET range examined, the frequency of transformation induced by the heavy ions increased sharply at very low doses no greater than 5 cGy. The relative biological effectiveness (RBE) of the heavy ions relative to 250 kVp X-rays showed an initial increase with LET, reaching a maximum value of about 7 at 100 keV/μm, and then decreased with the further increase in LET. Thus, we confirmed that high LET heavy ions are significantly more effective than X-rays for the induction of in vitro cell transformation.

Neoplastic transformation of hamster embyro cells by heavy ions.

PubMed

Han, Z; Suzuki, H; Suzuki, F; Suzuki, M; Furusawa, Y; Kato, T; Ikenaga, M

1998-01-01

We have studied the induction of morphological transformation of Syrian hamster embryo cells by low doses of heavy ions with different linear energy transfer (LET), ranging from 13 to 400 keV/micrometer. Exponentially growing cells were irradiated with 12C or 28Si ion beams generated by the Heavy Ion Medical Accelerator in Chiba (HIMAC), inoculated to culture dishes, and transformed colonies were identified when the cells were densely stacked and showed a crisscross pattern. Over the LET range examined, the frequency of transformation induced by the heavy ions increased sharply at very low doses no greater than 5 cGy. The relative biological effectiveness (RBE) of the heavy ions relative to 250 kVp X-rays showed an initial increase with LET, reaching a maximum value of about 7 at 100 keV/micrometer, and then decreased with the further increase in LET. Thus, we confirmed that high LET heavy ions are significantly more effective than X-rays for the induction of in vitro cell transformation.

Histological study of cell migration in the dermis of hamsters after immunisation with two different vaccines against visceral leishmaniasis.

PubMed

Moreira, Nádia das Dores; Giunchetti, Rodolfo Cordeiro; Carneiro, Cláudia Martins; Vitoriano-Souza, Juliana; Roatt, Bruno Mendes; Malaquias, Luiz Cosme Cotta; Corrêa-Oliveira, Rodrigo; Reis, Alexandre Barbosa

2009-04-15

Vaccine candidates, including live and/or killed parasites, Leishmania-purified fractions, defined recombinant antigens and antigen-encoding DNA-plasmids have been proposed to use as vaccine anti-Leishmania. More recently, the hamsters have been used to pre-selection of antigens candidate to apply in further experiments using canine model. In this report we evaluated the kinetics of cell migration in dermal inflammatory infiltrate, circulating leukocytes and the presence of nitric oxide (NO)/induced nitric oxide synthase during the early (1-24h) and late (48-168h) periods following inoculation of hamsters with antigenic components of anti-canine visceral leishmaniasis vaccines Leishmune and Leishmania braziliensis antigen (LB) with and without saponin (Sap) adjuvant. Our results show that LB caused an early reduction of lymphocytes in the dermis while Sap and LBSap triggered a late recruitment, suggesting the role of the adjuvant in the traffic of antigen-presenting cells and the induction of lymphocyte migration. In that manner our results suggest that the kinetics of cell migration on hamster model may be of value in the selection of vaccine antigens prior the tests in dogs particularly in respect of the toxicity of the preparations.

Prevention by cromakalim of spontaneously occurring cardiac necroses in polymyopathic hamsters.

PubMed

Jasmin, G; Proschek, L

1996-11-01

Previous studies on the heart necrotizing process at early stages of the hamster polymyopathy have led us to believe that this hereditary disease derives from a defective transmembrane ion flux resulting in myocardial Ca2+ over-load. On the other hand, certain K+ ATP channel openers were shown to prevent cytosolic Ca2+ accumulation in ischemic hearts. Therefore, we investigated the potential beneficial effect of chronic treatment with cromakalim (CR) on the development of necrotic changes in hamster myopathic hearts. Young cardiomyopathic (CM) hamsters were treated parenterally with CR over 4 consecutive weeks. The K+ ATP opener was dissolved in 5% DMSO and injected twice daily (s.c. and i.p. alternatively) at a dose level of 2.5 mg/kg per injection. Microscopic readings were carried out in staged serial paraffin sections of heart ventricles, the diaphragm, and tongue, will all tissues freshly taken at autopsy. In comparison with control untreated hearts, which exhibit numerous necrotic calcific foci, only minute myolytic lesions were found in 5 of 12 hamsters hearts receiving CR (p < 0.0001). Interestingly, the dystrophic process in the tongue was significantly less severe (p < 0.0004) in CR-treated animals. These observations provide evidence for the first time that in vivo sustained treatment with a K+ ATP opener exerts cardioprotection upon development of the hamster hereditary cardiomyopathy.

Defective TFH Cell Function and Increased TFR Cells Contribute to Defective Antibody Production in Aging.

PubMed

Sage, Peter T; Tan, Catherine L; Freeman, Gordon J; Haigis, Marcia; Sharpe, Arlene H

2015-07-14

Defective antibody production in aging is broadly attributed to immunosenescence. However, the precise immunological mechanisms remain unclear. Here, we demonstrate an increase in the ratio of inhibitory T follicular regulatory (TFR) cells to stimulatory T follicular helper (TFH) cells in aged mice. Aged TFH and TFR cells are phenotypically distinct from those in young mice, exhibiting increased programmed cell death protein-1 expression but decreased ICOS expression. Aged TFH cells exhibit defective antigen-specific responses, and programmed cell death protein-ligand 1 blockade can partially rescue TFH cell function. In contrast, young and aged TFR cells have similar suppressive capacity on a per-cell basis in vitro and in vivo. Together, these studies reveal mechanisms contributing to defective humoral immunity in aging: an increase in suppressive TFR cells combined with impaired function of aged TFH cells results in reduced T-cell-dependent antibody responses in aged mice. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Chromosomal mutations and chromosome loss measured in a new human-hamster hybrid cell line, ALC: studies with colcemid, ultraviolet irradiation, and 137Cs gamma-rays

NASA Technical Reports Server (NTRS)

Kraemer, S. M.; Waldren, C. A.; Chatterjee, A. (Principal Investigator)

1997-01-01

Small mutations, megabase deletions, and aneuploidy are involved in carcinogenesis and genetic defects, so it is important to be able to quantify these mutations and understand mechanisms of their creation. We have previously quantified a spectrum of mutations, including megabase deletions, in human chromosome 11, the sole human chromosome in a hamster-human hybrid cell line AL. S1- mutants have lost expression of a human cell surface antigen, S1, which is encoded by the M1C1 gene at 11p13 so that mutants can be detected via a complement-mediated cytotoxicity assay in which S1+ cells are killed and S1- cells survive. But loss of genes located on the tip of the short arm of 11 (11p15.5) is lethal to the AL hybrid, so that mutants that have lost the entire chromosome 11 die and escape detection. To circumvent this, we fused AL with Chinese hamster ovary (CHO) cells to produce a new hybrid, ALC, in which the requirement for maintaining 11p15.5 is relieved, allowing us to detect mutations events involving loss of 11p15.5. We evaluated the usefulness of this hybrid by conducting mutagenesis studies with colcemid, 137Cs gamma-radiation and UV 254 nm light. Colcemid induced 1000 more S1- mutants per unit dose in ALC than in AL; the increase for UV 254 nm light was only two-fold; and the increase for 137Cs gamma-rays was 12-fold. The increase in S1- mutant fraction in ALC cells treated with colcemid and 137Cs gamma-rays were largely due to chromosome loss and 11p deletions often containing a breakpoint within the centromeric region.

Mechanisms driving the lactate switch in Chinese hamster ovary cells.

PubMed

Hartley, Fiona; Walker, Tracy; Chung, Vicky; Morten, Karl

2018-03-31

The metabolism of Chinese Hamster Ovary (CHO) cells in a production environment has been extensively investigated. However, a key metabolic transition, the switch from lactate production to lactate consumption, remains enigmatic. Though commonly observed in CHO cultures, the mechanism(s) by which this metabolic shift is triggered is unknown. Despite this, efforts to control the switch have emerged due to the association of lactate consumption with improved cell growth and productivity. This review aims to consolidate current theories surrounding the lactate switch. The influence of pH, NAD + /NADH, pyruvate availability and mitochondrial function on lactate consumption are explored. A hypothesis based on the cellular redox state is put forward to explain the onset of lactate consumption. Various techniques implemented to control the lactate switch, including manipulation of the culture environment, genetic engineering, and cell line selection are also discussed. © 2018 Wiley Periodicals, Inc.

Targeted delivery of antigen to hamster nasal lymphoid tissue with M-cell-directed lectins.

PubMed Central

Giannasca, P J; Boden, J A; Monath, T P

1997-01-01

The nasal cavity of a rodent is lined by an epithelium organized into distinct regional domains responsible for specific physiological functions. Aggregates of nasal lymphoid tissue (NALT) located at the base of the nasal cavity are believed to be sites of induction of mucosal immune responses to airborne antigens. The epithelium overlying NALT contains M cells which are specialized for the transcytosis of immunogens, as demonstrated in other mucosal tissues. We hypothesized that NALT M cells are characterized by distinct glycoconjugate receptors which influence antigen uptake and immune responses to transcytosed antigens. To identify glycoconjugates that may distinguish NALT M cells from other cells of the respiratory epithelium (RE), we performed lectin histochemistry on sections of the hamster nasal cavity with a panel of lectins. Many classes of glycoconjugates were found on epithelial cells in this region. While most lectins bound to sites on both the RE and M cells, probes capable of recognizing alpha-linked galactose were found to label the follicle-associated epithelium (FAE) almost exclusively. By morphological criteria, the FAE contains >90% M cells. To determine if apical glycoconjugates on M cells were accessible from the nasal cavity, an M-cell-selective lectin and a control lectin in parallel were administered intranasally to hamsters. The M-cell-selective lectin was found to specifically target the FAE, while the control lectin did not. Lectin bound to M cells in vivo was efficiently endocytosed, consistent with the role of M cells in antigen transport. Intranasal immunization with lectin-test antigen conjugates without adjuvant stimulated induction of specific serum immunoglobulin G, whereas antigen alone or admixed with lectin did not. The selective recognition of NALT M cells by a lectin in vivo provides a model for microbial adhesin-host cell receptor interactions on M cells and the targeted delivery of immunogens to NALT following intranasal

Photoperiod-dependent modulation of anti-Müllerian hormone in female Siberian hamsters, Phodopus sungorus.

PubMed

Kabithe, Esther W; Place, Ned J

2008-03-01

Fertility and fecundity decline with advancing age in female mammals, but reproductive aging was decelerated in Siberian hamsters (Phodopus sungorus) raised in a short-day (SD) photoperiod. Litter success was significantly improved in older hamsters when reared in SD and the number of primordial follicles was twice that of females held in long days (LD). Because anti-Müllerian hormone (AMH) appears to inhibit the recruitment of primordial follicles in mice, we sought to determine whether the expression patterns of AMH differ in the ovaries and serum of hamsters raised in SD versus LD. Ovaries of SD female hamsters are characterized by a paucity of follicular development beyond the secondary stage and are endowed with an abundance of large eosinophilic cells, which may derive from granulosa cells of oocyte-depleted follicles. In ovaries from 10-week-old SD hamsters, we found that the so-called 'hypertrophied granulosa cells' were immunoreactive for AMH, as were granulosa cells within healthy-appearing primary and secondary follicles. Conversely, ovaries from age-matched LD animals lack the highly eosinophilic cells present in SD ovaries. Therefore, AMH staining in LD was limited to primary and secondary follicles that are comparable in number to those found in SD ovaries. The substantially greater AMH expression in SD ovaries probably reflects the abundance of hypertrophied granulosa cells in SD ovaries and their relative absence in LD ovaries. The modulation of ovarian AMH by day length is a strong mechanistic candidate for the preservation of primordial follicles in female hamsters raised in a SD photoperiod.

Characterisation of monoclonal antibodies specific for hamster leukocyte differentiation molecules.

PubMed

Rees, Jennifer; Haig, David; Mack, Victoria; Davis, William C

2017-01-01

Flow cytometry was used to identify mAbs that recognize conserved epitopes on hamster leukocyte differentiation molecules (hLDM) and also to characterize mAbs developed against hLDM. Initial screening of mAbs developed against LDMs in other species yielded mAbs specific for the major histocompatibility (MHC) II molecule, CD4 and CD18. Screening of sets of mAbs developed against hLDM yielded 22 new mAbs, including additional mAbs to MHC II molecules and mAbs that recognize LDMs expressed on all leukocytes, granulocytes, all lymphocytes, all T cells, a subset of T cells, or on all B cells. Based on comparison of the pattern of expression of LDMs expressed on all hamster leukocytes with the patterns of expression of known LDMs in other species, as detected by flow cytometry (FC), four mAbs are predicted to recognize CD11a, CD44, and CD45. Cross comparison of mAbs specific for a subset of hamster T cells with a cross reactive mAb known to recognize CD4 in mice and one recognising CD8 revealed they recognize CD4. The characterization of these mAbs expands opportunities to use hamsters as an additional model species to investigate the mechanisms of immunopathogenesis of infectious diseases. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Single Unit Recordings of Cells Responsive to Visual, Somatic, Acoustic, and Noxious Stimuli in the Superior Colliculus of the Golden Hamster.

DTIC Science & Technology

1978-08-01

Acoustic, and Noxious Stimuli Thesis in the Superior Colliculus of the Golden 6. PERFORMING OG. REPORT NUMBER Hamster -. _ // 7. AUTHOR( a ) S. CONTRACT...OR GRANT NUMBER(s) James P. Dixon I - "JV 9. PERF 7 MING ORGANIZATION NAME A D10. PROGRAM ELEMENT, PROJECT, TASK AFIT Student at: Virginia...studied in the superior colliculus of the golden hamster. A laminar organiza- tion was observed with cells in the superficial layers responding exclusively

Augmenting Chinese hamster genome assembly by identifying regions of high confidence.

PubMed

Vishwanathan, Nandita; Bandyopadhyay, Arpan A; Fu, Hsu-Yuan; Sharma, Mohit; Johnson, Kathryn C; Mudge, Joann; Ramaraj, Thiruvarangan; Onsongo, Getiria; Silverstein, Kevin A T; Jacob, Nitya M; Le, Huong; Karypis, George; Hu, Wei-Shou

2016-09-01

Chinese hamster Ovary (CHO) cell lines are the dominant industrial workhorses for therapeutic recombinant protein production. The availability of genome sequence of Chinese hamster and CHO cells will spur further genome and RNA sequencing of producing cell lines. However, the mammalian genomes assembled using shot-gun sequencing data still contain regions of uncertain quality due to assembly errors. Identifying high confidence regions in the assembled genome will facilitate its use for cell engineering and genome engineering. We assembled two independent drafts of Chinese hamster genome by de novo assembly from shotgun sequencing reads and by re-scaffolding and gap-filling the draft genome from NCBI for improved scaffold lengths and gap fractions. We then used the two independent assemblies to identify high confidence regions using two different approaches. First, the two independent assemblies were compared at the sequence level to identify their consensus regions as "high confidence regions" which accounts for at least 78 % of the assembled genome. Further, a genome wide comparison of the Chinese hamster scaffolds with mouse chromosomes revealed scaffolds with large blocks of collinearity, which were also compiled as high-quality scaffolds. Genome scale collinearity was complemented with EST based synteny which also revealed conserved gene order compared to mouse. As cell line sequencing becomes more commonly practiced, the approaches reported here are useful for assessing the quality of assembly and potentially facilitate the engineering of cell lines. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Morphometric and histological analysis of the lungs of Syrian golden hamsters.

PubMed Central

Kennedy, A R; Desrosiers, A; Terzaghi, M; Little, J B

1978-01-01

Hamster lung morphometry and histology have been studied in an attempt to determine differences between hamster and human lungs which may have relevance for lung carcinogenesis studies. Morphometric measurements were made on fresh lungs, lung casts, and histological sections. Cell type and frequency measurements were determined from frozen, paraffin, 1 micron plastic (glycol methacrylate) and electron microscopic sections. A standard terminology for hamster lung histology is established, and differences between hamster and human lung morphometry and histology are discussed. Images Fig. 2 Fig. 3 Fig. 4 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 Fig. 17 Fig. 18 Fig. 19 Fig. 20 Fig. 21 Fig. 22 PMID:640957

Stable Expression of the Motor Protein Prestin in Chinese Hamster Ovary Cells

NASA Astrophysics Data System (ADS)

Iida, Koji; Konno, Kazuaki; Oshima, Takeshi; Tsumoto, Kouhei; Ikeda, Katsuhisa; Kumagai, Izumi; Kobayashi, Toshimitsu; Wada, Hiroshi

Mammalian hearing sensitivity relies on a mechanical amplification mechanism involving the outer hair cells (OHCs), which rapidly alter their longitudinal length in response to changes in their membrane potential. The molecular basis of this mechanism is thought to be a motor protein embedded in the lateral membrane of the OHCs. Recently, this motor protein was identified and termed prestin. Since then, prestin has been researched intensively to elucidate the behavior of the OHCs. However, little progress in the study of prestin at the molecular level has been made because no method of obtaining an adequate amount of prestin has been established. In this study, therefore, an attempt was made to construct a stable expression system of prestin using Chinese hamster ovary (CHO) cells. The expression of prestin in the transfected CHO cells and the activity of prestin on CHO cells were confirmed by immunofluorescence and whole-cell patch-clamp measurements, respectively.

Inhibiting Sperm Pyruvate Dehydrogenase Complex and Its E3 Subunit, Dihydrolipoamide Dehydrogenase Affects Fertilization in Syrian Hamsters

PubMed Central

Sailasree, Purnima; Singh, Durgesh K.; Kameshwari, Duvurri B.; Shivaji, Sisinthy

2014-01-01

Background/Aims The importance of sperm capacitation for mammalian fertilization has been confirmed in the present study via sperm metabolism. Involvement of the metabolic enzymes pyruvate dehydrogenase complex (PDHc) and its E3 subunit, dihydrolipoamide dehydrogenase (DLD) in hamster in vitro fertilization (IVF) via in vitro sperm capacitation is being proposed through regulation of sperm intracellular lactate, pH and calcium. Methodology and Principal Findings Capacitated hamster spermatozoa were allowed to fertilize hamster oocytes in vitro which were then assessed for fertilization, microscopically. PDHc/DLD was inhibited by the use of the specific DLD-inhibitor, MICA (5-methoxyindole-2-carboxylic acid). Oocytes fertilized with MICA-treated (MT) [and thus PDHc/DLD-inhibited] spermatozoa showed defective fertilization where 2nd polar body release and pronuclei formation were not observed. Defective fertilization was attributable to capacitation failure owing to high lactate and low intracellular pH and calcium in MT-spermatozoa during capacitation. Moreover, this defect could be overcome by alkalinizing spermatozoa, before fertilization. Increasing intracellular calcium in spermatozoa pre-IVF and in defectively-fertilized oocytes, post-fertilization rescued the arrest seen, suggesting the role of intracellular calcium from either of the gametes in fertilization. Parallel experiments carried out with control spermatozoa capacitated in medium with low extracellular pH or high lactate substantiated the necessity of optimal sperm intracellular lactate levels, intracellular pH and calcium during sperm capacitation, for proper fertilization. Conclusions This study confirms the importance of pyruvate/lactate metabolism in capacitating spermatozoa for successful fertilization, besides revealing for the first time the importance of sperm PDHc/ DLD in fertilization, via the modulation of sperm intracellular lactate, pH and calcium during capacitation. In addition, the

Alpha 1-protease inhibitor moderates human neutrophil elastase-induced emphysema and secretory cell metaplasia in hamsters.

PubMed

Stone, P J; Lucey, E C; Virca, G D; Christensen, T G; Breuer, R; Snider, G L

1990-06-01

A study was undertaken to determine whether emphysema and airway secretory cell metaplasia, induced in hamsters by intratracheal treatment with human neutrophil elastase (HNE), could be moderated by pretreatment with human alpha 1-protease inhibitor (API). API (4.9 mg) was given intratracheally to hamsters 1 h before 0.3 mg HNE. Eight weeks later, lung volumes and pressure-volume relationships were measured in the anaesthetized animals. Mean linear intercepts and secretory cell indices were measured in lung sections. API given 1 h before HNE moderated the development of bronchial secretory cell metaplasia. The severity of emphysema was reduced by 75%. Clearance studies indicated that 80% of the functional activity of instilled API could be lavaged from the lungs after 1 h, indicating a 4 h half-life in the lavageable compartment of the lungs. We calculate that for 50% protection from emphysema the molar ratio of lavageable API to HNE at the time of HNE instillation was 4.8 as compared with 0.78 for 50% inhibition of elastolytic activity in vitro, indicating that API is only 16% as efficient in vivo as compared with its in vitro HNE inhibitory effectiveness. Nevertheless, we conclude that human API given intratracheally is efficacious against HNE-induced emphysema and secretory cell metaplasia.

Early effect of boron neutron capture therapy mediated by boronophenylalanine (BPA-BNCT) on mast cells in premalignant tissue and tumors of the hamster cheek pouch.

PubMed

Aromando, Romina F; Trivillin, Verónica A; Heber, Elisa M; Pozzi, Emiliano; Schwint, Amanda E; Itoiz, María E

2010-05-01

Mast cell (MC) activation in the hamster cheek pouch cancerization model is associated with the increase in tumor cell proliferation, mediated in turn by tryptase, a protease released from mast cell granules after activation. Tryptase induces tumor cell proliferation through the activation of PAR-2 (protease activated receptor-2) on the plasma membrane of carcinoma cells. The therapeutic success of boron neutron capture therapy mediated by boronophenylalanine (BPA-BNCT) in tumor control in the hamster cheek pouch oral cancer model has been previously reported by our laboratory. Early effects of BPA-BNCT on tumors of the hamster cheek pouch include a reduction in DNA-synthesis with the concomitant decrease in the proliferation of malignant cells. The aim of the present study was to investigate the early histological changes in mast cells after BPA-BNCT in tumors and premalignant tissue of the hamster cheek pouch. Tumor-bearing pouches were treated with BPA-BNCT or beam only (neutron irradiation without prior administration of the boron compound) and sacrificed 1day after treatment. The samples were fixed in Carnoy fixative and stained with alcian blue-safranin to identify all the populations of mast cells. Total, active and inactive mast cells (MC) were counted in the connective tissue and the adventitious tissue underlying the pouch wall and at the base of the tumors in pouches treated with BPA-BNCT, in keeping with a previously described technique. BPA-BNCT induced a marked reduction in the total number of mast cells in the pouch (p<0.05). This reduction in the total number of mast cells was due to a reduction in mast cells at the base of the tumor (p<0.005) and it occurred at the expense of the active mast cells (p<0.05). A slight reduction that did not reach statistical significance also occurred in the amount of mast cells in the pouch wall (that corresponds to the premalignant tissue in tumor-bearing pouches), and in the adventitious tissue. In this case the

The antioxidant effect of the Malaysian Gelam honey on pancreatic hamster cells cultured under hyperglycemic conditions.

PubMed

Batumalaie, Kalaivani; Qvist, Rajes; Yusof, Kamaruddin Mohd; Ismail, Ikram Shah; Sekaran, Shamala Devi

2014-05-01

Type 2 diabetes consists of progressive hyperglycemia, insulin resistance, and pancreatic β-cell failure which could result from glucose toxicity, inflammatory cytokines, and oxidative stress. In the present study, we investigate the effect of pretreatment with Gelam honey (Melaleuca spp.) and the individual flavonoid components chrysin, luteolin, and quercetin, on the production of reactive oxygen species (ROS), cell viability, lipid peroxidation, and insulin content in hamster pancreatic cells (HIT-T15 cells), cultured under normal and hyperglycemic conditions. Phenolic extracts from a local Malaysian species of Gelam honey (Melaleuca spp.) were prepared using the standard extraction methods. HIT-T15 cells were cultured in 5 % CO2 and then preincubated with Gelam honey extracts (20, 40, 60, and 80 μg/ml) as well as some of its flavonoid components chrysin, luteolin, and quercetin (20, 40, 60, and 80 μM), prior to stimulation by 20 and 50 mM of glucose. The antioxidative effects were measured in these cultured cells at different concentrations and time point by DCFH-DA assay. Pretreatment of cells with Gelam honey extract or the flavonoid components prior to culturing in 20 or 50 mM glucose showed a significant decrease in the production of ROS, glucose-induced lipid peroxidation, and a significant increase in insulin content and the viability of cells cultured under hyperglycemic condition. Our results show the in vitro antioxidative property of the Gelam honey and the flavonoids on the β-cells from hamsters and its cytoprotective effect against hyperglycemia.

Sequencing, Annotation and Analysis of the Syrian Hamster (Mesocricetus auratus) Transcriptome

PubMed Central

Tchitchek, Nicolas; Safronetz, David; Rasmussen, Angela L.; Martens, Craig; Virtaneva, Kimmo; Porcella, Stephen F.; Feldmann, Heinz

2014-01-01

Background The Syrian hamster (golden hamster, Mesocricetus auratus) is gaining importance as a new experimental animal model for multiple pathogens, including emerging zoonotic diseases such as Ebola. Nevertheless there are currently no publicly available transcriptome reference sequences or genome for this species. Results A cDNA library derived from mRNA and snRNA isolated and pooled from the brains, lungs, spleens, kidneys, livers, and hearts of three adult female Syrian hamsters was sequenced. Sequence reads were assembled into 62,482 contigs and 111,796 reads remained unassembled (singletons). This combined contig/singleton dataset, designated as the Syrian hamster transcriptome, represents a total of 60,117,204 nucleotides. Our Mesocricetus auratus Syrian hamster transcriptome mapped to 11,648 mouse transcripts representing 9,562 distinct genes, and mapped to a similar number of transcripts and genes in the rat. We identified 214 quasi-complete transcripts based on mouse annotations. Canonical pathways involved in a broad spectrum of fundamental biological processes were significantly represented in the library. The Syrian hamster transcriptome was aligned to the current release of the Chinese hamster ovary (CHO) cell transcriptome and genome to improve the genomic annotation of this species. Finally, our Syrian hamster transcriptome was aligned against 14 other rodents, primate and laurasiatheria species to gain insights about the genetic relatedness and placement of this species. Conclusions This Syrian hamster transcriptome dataset significantly improves our knowledge of the Syrian hamster's transcriptome, especially towards its future use in infectious disease research. Moreover, this library is an important resource for the wider scientific community to help improve genome annotation of the Syrian hamster and other closely related species. Furthermore, these data provide the basis for development of expression microarrays that can be used in functional

Unusual neutral oligosaccharides in mature Sindbis virus glycoproteins are synthesized from truncated precursor oligosaccharides in Chinese hamster ovary cells.

PubMed

Davidson, S K; Hunt, L A

1983-03-01

We have previously demonstrated the presence of unusual small asparaginyl-oligosaccharides [(Man)3GlcNAc2-ASN] in the mature glycoproteins of Sindbis virus released from both wild-type and lectin-resistant Chinese hamster ovary cells, but the mechanism of synthesis of these structures was not determined. Gel filtration and endo-beta-N-acetylglucosaminidase analyses of Pronase-digested glycopeptides from [3H]mannose-labelled Sindbis virus released at different times after infection of a phytohaemagglutinin-resistant line of Chinese hamster ovary cells demonstrated that these small asparaginyl-oligosaccharides were present in similar relative amounts in virus released throughout the virus infection, rather than arising primarily at late times when cytopathic effects were maximal. Similar analyses of pulse-labelled, cell-associated viral glycopeptides suggested that these small oligosaccharides on mature virus glycoprotein resulted from the normal alpha 1,2-mannosidase processing of truncated precursor oligosaccharides (containing five rather than nine mannoses), rather than from aberrant processing or degradation of the full-size precursor oligosaccharides or normal intermediates.

Caffeine-enhanced survival of radiation-sensitive, repair-deficient Chinese hamster cells

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

Utsumi, H.; Elkind, M.M.

1983-11-01

A clone of V79 Chinese hamster cells (V79-AL162/S-10) with unique properties has been isolated after a challenge of parental cells (V79-AL162) with 1 mM ouabain. Compared with parental cells, or with other clones isolated after the ouabain challenge, these cells form smaller colonies, are more sensitive to both x rays and fission-spectrum neutrons, and respond atypically to a postirradiation treatment with caffeine. Their enhanced response to x rays results mainly from a large reduction in the shoulder of their survival curve, probably because in late S phase, the most resistant phase in the cell cycle, the survival curve of thesemore » cells has a reduced shoulder width. Caffeine, and to a lesser extent theophylline, added to the colony-forming medium immediately after exposure appreciably increases the width of the shoulder of these sensitive cells, whereas caffeine has the opposite effect on the response of normal V79 cells. Thus the unique response of the V79-AL162/S-10 cells to a radiation posttreatment with caffeine (increased survival) results from a net increase in their ability to repair damage that is otherwise lethal; caffeine treatment ordinarly prevents normal V79 cells from repairing damage that is only potentially lethal.« less

Effects of proliferation on the decay of thermotolerance in Chinese hamster cells.

PubMed

Armour, E P; Li, G C; Hahn, G M

1985-09-01

Development and decay of thermotolerance were observed in Chinese hamster HA-1 cells. The thermotolerance kinetics of exponentially growing and fed plateau-phase cells were compared. Following a 10-min heat exposure at 45 degrees C, cells in both growth states had similar rates of development of tolerance to a subsequent 45-min exposure at 45 degrees C. This thermotolerant state started to decay between 12 and 24 hr after the initial heat exposure. The decay appeared to initiate slightly sooner in the exponentially growing cells when compared to the fed plateau-phase cells. During the decay phase, the rate of thermotolerance decay was similar in the two growth conditions. In other experiments, cells were induced to divide at a slower rate by chronic growth (3 months) in a low concentration of fetal calf serum. Under these low serum conditions cells became more sensitive to heat and the rate of decay of thermotolerance remained the same for exponentially growing cells. Plateau-phase cells were also more sensitive, but thermotolerance decayed more rapidly in these cells. Although dramatic cell cycle perturbations were seen in the exponentially growing cells, these changes appeared not to be related to thermotolerance kinetics.

Decreased adult neurogenesis in hibernating Syrian hamster.

PubMed

León-Espinosa, Gonzalo; García, Esther; Gómez-Pinedo, Ulises; Hernández, Félix; DeFelipe, Javier; Ávila, Jesús

2016-10-01

Generation of new neurons from adult neural stem cells occurs in the dentate gyrus (DG) of the hippocampus and the lateral walls of the lateral ventricles. In this article, we study the neurogenesis that takes place during the hibernation of the Syrian hamster (Mesocricetus auratus). Using a variety of standard neurogenesis markers and 5-bromo-2-deoxyuridine (BrdU) incorporation, we describe a preferential decrease in the proliferation of newborn neurons in the subventricular zone (SVZ) of the hibernating hamsters (torpor) rather than in the hippocampus. Furthermore, we demonstrate that the proliferative capacity is recovered after 3-4days of torpor when arousal is triggered under natural conditions (i.e., not artificially provoked). In addition, we show that tau3R, a tau isoform with three microtubule-binding domains, is a suitable marker to study neurogenesis both in the SVZ and subgranular zone (SGZ) of the Syrian hamster brain. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Syngeneic syrian hamster tumors feature tumor-infiltrating lymphocytes allowing adoptive cell therapy enhanced by oncolytic adenovirus in a replication permissive setting.

PubMed

Siurala, Mikko; Vähä-Koskela, Markus; Havunen, Riikka; Tähtinen, Siri; Bramante, Simona; Parviainen, Suvi; Mathis, J Michael; Kanerva, Anna; Hemminki, Akseli

2016-05-01

Adoptive transfer of tumor-infiltrating lymphocytes (TIL) has shown promising yet sometimes suboptimal results in clinical trials for advanced cancer, underscoring the need for approaches improving efficacy and safety. Six implantable syngeneic tumor cell lines of the Syrian hamster were used to initiate TIL cultures. TIL generated from tumor fragments cultured in human interleukin-2 (IL-2) for 10 d were adoptively transferred into tumor-bearing hamsters with concomitant intratumoral injections of oncolytic adenovirus (Ad5-D24) for the assessment of antitumor efficacy. Pancreatic cancer (HapT1) and melanoma (RPMI 1846) TIL exhibited potent and tumor-specific cytotoxicity in effector-to-target (E/T) assays. MHC Class I blocking abrogated the cell killing of RPMI 1846 TIL, indicating cytotoxic CD8(+) T-cell activity. When TIL were combined with Ad5-D24 in vitro, HapT1 tumor cell killing was significantly enhanced over single agents. In vivo, the intratumoral administration of HapT1 TIL and Ad5-D24 resulted in improved tumor growth control compared with either treatment alone. Additionally, splenocytes derived from animals treated with the combination of Ad5-D24 and TIL killed autologous tumor cells more efficiently than monotherapy-derived splenocytes, suggesting that systemic antitumor immunity was induced. For the first time, TIL of the Syrian hamster have been cultured, characterized and used therapeutically together with oncolytic adenovirus for enhancing the efficacy of TIL therapy. Our results support human translation of oncolytic adenovirus as an enabling technology for adoptive T-cell therapy of solid tumors.

Syngeneic syrian hamster tumors feature tumor-infiltrating lymphocytes allowing adoptive cell therapy enhanced by oncolytic adenovirus in a replication permissive setting

PubMed Central

Siurala, Mikko; Vähä-Koskela, Markus; Havunen, Riikka; Tähtinen, Siri; Bramante, Simona; Parviainen, Suvi; Mathis, J. Michael; Kanerva, Anna; Hemminki, Akseli

2016-01-01

ABSTRACT Adoptive transfer of tumor-infiltrating lymphocytes (TIL) has shown promising yet sometimes suboptimal results in clinical trials for advanced cancer, underscoring the need for approaches improving efficacy and safety. Six implantable syngeneic tumor cell lines of the Syrian hamster were used to initiate TIL cultures. TIL generated from tumor fragments cultured in human interleukin-2 (IL-2) for 10 d were adoptively transferred into tumor-bearing hamsters with concomitant intratumoral injections of oncolytic adenovirus (Ad5-D24) for the assessment of antitumor efficacy. Pancreatic cancer (HapT1) and melanoma (RPMI 1846) TIL exhibited potent and tumor-specific cytotoxicity in effector-to-target (E/T) assays. MHC Class I blocking abrogated the cell killing of RPMI 1846 TIL, indicating cytotoxic CD8+ T-cell activity. When TIL were combined with Ad5-D24 in vitro, HapT1 tumor cell killing was significantly enhanced over single agents. In vivo, the intratumoral administration of HapT1 TIL and Ad5-D24 resulted in improved tumor growth control compared with either treatment alone. Additionally, splenocytes derived from animals treated with the combination of Ad5-D24 and TIL killed autologous tumor cells more efficiently than monotherapy-derived splenocytes, suggesting that systemic antitumor immunity was induced. For the first time, TIL of the Syrian hamster have been cultured, characterized and used therapeutically together with oncolytic adenovirus for enhancing the efficacy of TIL therapy. Our results support human translation of oncolytic adenovirus as an enabling technology for adoptive T-cell therapy of solid tumors. PMID:27467954

The insecticide buprofezin induces morphological transformation and kinetochore-positive micronuclei in cultured Syrian hamster embryo cells in the absence of detectable DNA damage.

PubMed

Herrera, L A; Ostrosky-Wegman, P; Schiffmann, D; Chen, Q Y; Ziegler-Skylakakis, K; Andrae, U

1993-11-01

The insecticide buprofezin was examined for its genotoxicity in cultured Syrian hamster embryo cells in order to better understand the mechanisms underlying the genotoxicity of the compound in mammalian cells. Exposure to buprofezin concentrations of 12.5-100 microM did not significantly affect the colony-forming ability of the cells, but did result in increased frequencies of morphologically transformed colonies. Treatment with buprofezin did not cause a detectable induction of DNA repair synthesis, an indicator of DNA damage, but significantly increased the frequency of micronuclei. Immunostaining of the cells with antikinetochore antibody (CREST antibody) showed that essentially all of the buprofezin-induced micronuclei were kinetochore-positive. The results suggest that morphological transformation of Syrian hamster embryo cells by buprofezin results from an interaction of the compound or a metabolite of it with the mitotic apparatus rather than from DNA damage.

Identifying Early Target Cells of Nipah Virus Infection in Syrian Hamsters

PubMed Central

Baseler, Laura; Scott, Dana P.; Saturday, Greg; Horne, Eva; Rosenke, Rebecca; Thomas, Tina; Meade-White, Kimberly; Haddock, Elaine; Feldmann, Heinz

2016-01-01

Background Nipah virus causes respiratory and neurologic disease with case fatality rates up to 100% in individual outbreaks. End stage lesions have been described in the respiratory and nervous systems, vasculature and often lymphoid organs in fatal human cases; however, the initial target organs of Nipah virus infection have not been identified. Here, we detected the initial target tissues and cells of Nipah virus and tracked virus dissemination during the early phase of infection in Syrian hamsters inoculated with a Nipah virus isolate from Malaysia (NiV-M) or Bangladesh (NiV-B). Methodology/Principal Findings Syrian hamsters were euthanized between 4 and 48 hours post intranasal inoculation and tissues were collected and analyzed for the presence of viral RNA, viral antigen and infectious virus. Virus replication was first detected at 8 hours post inoculation (hpi). Nipah virus initially targeted type I pneumocytes, bronchiolar respiratory epithelium and alveolar macrophages in the lung and respiratory and olfactory epithelium lining the nasal turbinates. By 16 hpi, virus disseminated to epithelial cells lining the larynx and trachea. Although the pattern of viral dissemination was similar for both virus isolates, the rate of spread was slower for NiV-B. Infectious virus was not detected in the nervous system or blood and widespread vascular infection and lesions within lymphoid organs were not observed, even at 48 hpi. Conclusions/Significance Nipah virus initially targets the respiratory system. Virus replication in the brain and infection of blood vessels in non-respiratory tissues does not occur during the early phase of infection. However, virus replicates early in olfactory epithelium and may serve as the first step towards nervous system dissemination, suggesting that development of vaccines that block virus dissemination or treatments that can access the brain and spinal cord and directly inhibit virus replication may be necessary for preventing central

Identifying Early Target Cells of Nipah Virus Infection in Syrian Hamsters.

PubMed

Baseler, Laura; Scott, Dana P; Saturday, Greg; Horne, Eva; Rosenke, Rebecca; Thomas, Tina; Meade-White, Kimberly; Haddock, Elaine; Feldmann, Heinz; de Wit, Emmie

2016-11-01

Nipah virus causes respiratory and neurologic disease with case fatality rates up to 100% in individual outbreaks. End stage lesions have been described in the respiratory and nervous systems, vasculature and often lymphoid organs in fatal human cases; however, the initial target organs of Nipah virus infection have not been identified. Here, we detected the initial target tissues and cells of Nipah virus and tracked virus dissemination during the early phase of infection in Syrian hamsters inoculated with a Nipah virus isolate from Malaysia (NiV-M) or Bangladesh (NiV-B). Syrian hamsters were euthanized between 4 and 48 hours post intranasal inoculation and tissues were collected and analyzed for the presence of viral RNA, viral antigen and infectious virus. Virus replication was first detected at 8 hours post inoculation (hpi). Nipah virus initially targeted type I pneumocytes, bronchiolar respiratory epithelium and alveolar macrophages in the lung and respiratory and olfactory epithelium lining the nasal turbinates. By 16 hpi, virus disseminated to epithelial cells lining the larynx and trachea. Although the pattern of viral dissemination was similar for both virus isolates, the rate of spread was slower for NiV-B. Infectious virus was not detected in the nervous system or blood and widespread vascular infection and lesions within lymphoid organs were not observed, even at 48 hpi. Nipah virus initially targets the respiratory system. Virus replication in the brain and infection of blood vessels in non-respiratory tissues does not occur during the early phase of infection. However, virus replicates early in olfactory epithelium and may serve as the first step towards nervous system dissemination, suggesting that development of vaccines that block virus dissemination or treatments that can access the brain and spinal cord and directly inhibit virus replication may be necessary for preventing central nervous system pathology.

Process-induced defects in terrestrial solar cells

NASA Technical Reports Server (NTRS)

Lindholm, F. A.; Li, S. S.; Sah, C. T.

1975-01-01

Experimental and theoretical work on low resistivity, high efficiency solar cells indicates the dominant role that defects take in determining performance. High doping mechanisms produce gap shrinkage by band tailing, impurity band widening and impurity misfit; altered interband transmission rates result from Auger impact, SRH processes, or from electronic tunneling via defects. Characterizations of cell materials for their defects and their relations to the chosen fabrication processes are proposed.

Characterization of an N-Terminal Non-Core Domain of RAG1 Gene Disrupted Syrian Hamster Model Generated by CRISPR Cas9.

PubMed

Miao, Jinxin; Ying, Baoling; Li, Rong; Tollefson, Ann E; Spencer, Jacqueline F; Wold, William S M; Song, Seok-Hwan; Kong, Il-Keun; Toth, Karoly; Wang, Yaohe; Wang, Zhongde

2018-05-06

The accumulating evidence demonstrates that Syrian hamsters have advantages as models for various diseases. To develop a Syrian hamster ( Mesocricetus auratus ) model of human immunodeficiency caused by RAG1 gene mutations, we employed the CRISPR/Cas9 system and introduced an 86-nucleotide frameshift deletion in the hamster RAG1 gene encoding part of the N-terminal non-core domain of RAG1. Histological and immunohistochemical analyses demonstrated that these hamsters (referred herein as RAG1-86nt hamsters) had atrophic spleen and thymus, and developed significantly less white pulp and were almost completely devoid of splenic lymphoid follicles. The RAG1-nt86 hamsters had barely detectable CD3⁺ and CD4⁺ T cells. The expression of B and T lymphocyte-specific genes (CD3γ and CD4 for T cell-specific) and (CD22 and FCMR for B cell-specific) was dramatically reduced, whereas the expression of macrophage-specific (CD68) and natural killer (NK) cell-specific (CD94 and KLRG1) marker genes was increased in the spleen of RAG1-nt86 hamsters compared to wildtype hamsters. Interestingly, despite the impaired development of B and T lymphocytes, the RAG1-86nt hamsters still developed neutralizing antibodies against human adenovirus type C6 (HAdV-C6) upon intranasal infection and were capable of clearing the infectious viruses, albeit with slower kinetics. Therefore, the RAG1-86nt hamster reported herein (similar to the hypomorphic RAG1 mutations in humans that cause Omenn syndrome), may provide a useful model for studying the pathogenesis of the specific RAG1-mutation-induced human immunodeficiency, the host immune response to adenovirus infection and other pathogens as well as for evaluation of cell and gene therapies for treatment of this subset of RAG1 mutation patients.

Identification of hamster inducible nitric oxide synthase (iNOS) promoter sequences that influence basal and inducible iNOS expression

PubMed Central

Saldarriaga, Omar A.; Travi, Bruno L.; Choudhury, Goutam Ghosh; Melby, Peter C.

2012-01-01

IFN-γ/LPS-activated hamster (Mesocricetus auratus) macrophages express significantly less iNOS (NOS2) than activated mouse macrophages, which contributes to the hamster's susceptibility to intracellular pathogens. We determined a mechanism responsible for differences in iNOS promoter activity in hamsters and mice. The HtPP (1.2 kb) showed low basal and inducible promoter activity when compared with the mouse, and sequences within a 100-bp region (−233 to −133) of the mouse and hamster promoters influenced this activity. Moreover, within this 100 bp, we identified a smaller region (44 bp) in the mouse promoter, which recovered basal promoter activity when swapped into the hamster promoter. The mouse homolog (100-bp region) contained a cis-element for NF-IL-6 (−153/−142), which was absent in the hamster counterpart. EMSA and supershift assays revealed that the hamster sequence did not support the binding of NF-IL-6. Introduction of a functional NF-IL-6 binding sequence into the hamster promoter or its alteration in the mouse promoter revealed the critical importance of this transcription factor for full iNOS promoter activity. Furthermore, the binding of NF-IL-6 to the iNOS promoter (−153/−142) in vivo was increased in mouse cells but was reduced in hamster cells after IFN-γ/LPS stimulation. Differences in the activity of the iNOS promoters were evident in mouse and hamster cells, so they were not merely a result of species-specific differences in transcription factors. Thus, we have identified unique DNA sequences and a critical transcription factor, NF-IL-6, which contribute to the overall basal and inducible expression of hamster iNOS. PMID:22517919

Lymphocyte function in experimental endemic syphilis of Syrian hamsters.

PubMed Central

Bagasra, O; Kushner, H; Hashemi, S

1985-01-01

We have studied the changes in the lymph nodes, spleen and thymus that occur in inbred LSH Syrian hamsters infected with Treponema pallidum Bosnia A, the causative agent of endemic syphilis, as well as the B-cell responses of these infected animals to helper T-cell independent and dependent antigens. The lymph nodes increased significantly in weight up to 6 weeks after infection, and contained viable treponemes. No significant changes in the spleen weight were observed, and no viable treponemes could be recovered from the spleen. However, the size of the thymus decreased steadily during the course of the disease. The relative number of Ig+ cells (B cells) increased in the spleen and regional lymph nodes, whereas the relative number of T cells decreased during the course of infection. In both the spleen and lymph nodes, the relative number of macrophages increased initially and decreased thereafter in the form of a bell-shaped curve showing a peak at 4-6 weeks of infection. The ability of splenic lymphocytes from infected hamsters to mount a primary PFC response to pneumococcal polysaccharide type III (SIII), a helper T-cell independent antigen, was elevated throughout the course of infection. However, the splenic PFC response to sheep erythrocytes (SRBC), a helper T-cell dependent antigen, was increased only during the first 4 weeks of infection and progressively decreased thereafter. The PFC responses of infected lymph node lymphocytes to both SIII and SRBC were increased during the first 4 weeks and decreased thereafter. These data suggested that atrophy of the thymus seen in syphilitic infection is accompanied by the complex losses of subsets of T cells and altered B-cell functions. An early loss of suppressor T cells in both the lymph nodes and spleen occurs concomitantly with a loss of T helper cells and heterologous (treponema-unrelated) B-cell functions in the lymph nodes. Helper T cells are lost from the spleen only in the later stages of infection, whereas

Expression of vascular endothelial growth factor does not promote transformation but confers a growth advantage in vivo to Chinese hamster ovary cells.

PubMed Central

Ferrara, N; Winer, J; Burton, T; Rowland, A; Siegel, M; Phillips, H S; Terrell, T; Keller, G A; Levinson, A D

1993-01-01

Vascular endothelial growth factor (VEGF) is a mitogen with a specificity for endothelial cells in vitro and an angiogenic inducer in vivo. We tested the hypothesis that VEGF may confer on expressing cells a growth advantage in vivo. Dihydrofolatereductase--Chinese hamster ovary cells were transfected with expression vectors which direct the constitutive synthesis of VEGF. Neither the expression nor the exogenous administration of VEGF stimulated anchorage-dependent or anchorage-independent growth of Chinese hamster ovary cells in vitro. However, VEGF-expressing clones, unlike control cells, demonstrated an ability to proliferate in nude mice. Histologic examination revealed that the proliferative lesions were compact, well vascularized, and nonedematous. Ultrastructural analysis revealed that capillaries within the lesions were of the continuous type. These findings indicate that the expression of VEGF may confer on cells the ability to grow in vivo in the absence of transformation by purely paracrine mechanisms. Since VEGF is a widely distributed protein, this property may have relevance for a variety of physiological and pathological proliferative processes. Images PMID:8423215

Cell and defect behavior in lithium-counterdoped solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Mehta, S.; Swartz, C. K.

1984-01-01

Some n(+)/p cells in which lithium is introduced as a counterdopant, by ion-implantation, into the cell's boron-doped p-region were studied. To determine if the cells radiation resistance could be significantly improved by lithium counterdoping. Defect behavior was related to cell performance using deep level transient spectroscopy. Results indicate a significantly increased radiation resistance for the lithium counterdoped cells when compared to the boron doped 1 ohm-cm control cell. The increased radiation resistance of the lithium counterdoped cells is due to the complexing of lithium with divacancies and boron. It is speculated that complexing with oxygen and single vacancies also contributes to the increased radiation resistance. Counterdoping silicon with lithium results in a different set of defects.

Antigenic specificity and morphologic characteristics of Chlamydia trachomatis, strain SFPD, isolated from hamsters with proliferative ileitis.

PubMed

Fox, J G; Stills, H F; Paster, B J; Dewhirst, F E; Yan, L; Palley, L; Prostak, K

1993-10-01

Profound diarrhea associated with proliferating intestinal cells containing intraepithelial campylobacter-like organisms (ICLO) occurs in a variety of mammalian hosts, particularly swine and hamsters. Recently, intracellular bacteria were isolated from proliferative intestinal tissue of hamsters and propagated in intestine cell line 407. Oral inoculation of hamsters with cell culture lysates containing these organisms reproduced the disease in susceptible hamsters. In the present study, an intracellular bacterium from the INT 407 cell line was shown by a variety of techniques to be a member of the genus Chlamydia and has been designated Chlamydia sp. strain SFPD. McCoy cells infected with Chlamydia sp. strain SFPD demonstrated bright fluorescent-stained intracytoplasmic inclusions when examined with fluorescein-labeled species-specific C. trachomatis monoclonal antibodies. The organism also reacted to fluorescein-labeled polyclonal but not monoclonal ICLO "omega" antisera. Ultrastructural examination of the Chlamydia sp. strain SFPD from McCoy cells revealed electrondense elementary bodies and a less electron-dense reticulate-like body that was circular; both features are consistent in morphology to developmental forms of Chlamydia and do not conform to ICLO morphology. Molecular studies, 16S ribosomal sequence analysis, and sequencing of the outer membrane protein confirmed that the isolate is a C. trachomatis closely related to the mouse pneumonitis strain of C. trachomatis.

Topological defects in epithelia govern cell death and extrusion

NASA Astrophysics Data System (ADS)

Saw, Thuan Beng; Doostmohammadi, Amin; Nier, Vincent; Kocgozlu, Leyla; Thampi, Sumesh; Toyama, Yusuke; Marcq, Philippe; Lim, Chwee Teck; Yeomans, Julia M.; Ladoux, Benoit

2017-04-01

Epithelial tissues (epithelia) remove excess cells through extrusion, preventing the accumulation of unnecessary or pathological cells. The extrusion process can be triggered by apoptotic signalling, oncogenic transformation and overcrowding of cells. Despite the important linkage of cell extrusion to developmental, homeostatic and pathological processes such as cancer metastasis, its underlying mechanism and connections to the intrinsic mechanics of the epithelium are largely unexplored. We approach this problem by modelling the epithelium as an active nematic liquid crystal (that has a long range directional order), and comparing numerical simulations to strain rate and stress measurements within monolayers of MDCK (Madin Darby canine kidney) cells. Here we show that apoptotic cell extrusion is provoked by singularities in cell alignments in the form of comet-shaped topological defects. We find a universal correlation between extrusion sites and positions of nematic defects in the cell orientation field in different epithelium types. The results confirm the active nematic nature of epithelia, and demonstrate that defect-induced isotropic stresses are the primary precursors of mechanotransductive responses in cells, including YAP (Yes-associated protein) transcription factor activity, caspase-3-mediated cell death, and extrusions. Importantly, the defect-driven extrusion mechanism depends on intercellular junctions, because the weakening of cell-cell interactions in an α-catenin knockdown monolayer reduces the defect size and increases both the number of defects and extrusion rates, as is also predicted by our model. We further demonstrate the ability to control extrusion hotspots by geometrically inducing defects through microcontact printing of patterned monolayers. On the basis of these results, we propose a mechanism for apoptotic cell extrusion: spontaneously formed topological defects in epithelia govern cell fate. This will be important in predicting

Effect of Saw Palmetto Supplements on Androgen-Sensitive LNCaP Human Prostate Cancer Cell Number and Syrian Hamster Flank Organ Growth

PubMed Central

Opoku-Acheampong, Alexander B.; Penugonda, Kavitha; Lindshield, Brian L.

2016-01-01

Saw palmetto supplements (SPS) are commonly consumed by men with prostate cancer. We investigated whether SPS fatty acids and phytosterols concentrations determine their growth-inhibitory action in androgen-sensitive LNCaP cells and hamster flank organs. High long-chain fatty acids-low phytosterols (HLLP) SPS ≥ 750 nM with testosterone significantly increased and ≥500 nM with dihydrotestosterone significantly decreased LNCaP cell number. High long-chain fatty acids-high phytosterols (HLHP) SPS ≥ 500 nM with dihydrotestosterone and high medium-chain fatty acids-low phytosterols (HMLP) SPS ≥ 750 nM or with androgens significantly decreased LNCaP cell number (n = 3; p < 0.05). Five- to six-week-old, castrated male Syrian hamsters were randomized to control (n = 4), HLLP, HLHP, and HMLP SPS (n = 6) groups. Testosterone or dihydrotestosterone was applied topically daily for 21 days to the right flank organ; the left flank organ was treated with ethanol and served as the control. Thirty minutes later, SPS or ethanol was applied to each flank organ in treatment and control groups, respectively. SPS treatments caused a notable but nonsignificant reduction in the difference between left and right flank organ growth in testosterone-treated SPS groups compared to the control. The same level of inhibition was not seen in dihydrotestosterone-treated SPS groups (p < 0.05). Results may suggest that SPS inhibit 5α-reductase thereby preventing hamster flank organ growth. PMID:27272436

Effect of Saw Palmetto Supplements on Androgen-Sensitive LNCaP Human Prostate Cancer Cell Number and Syrian Hamster Flank Organ Growth.

PubMed

Opoku-Acheampong, Alexander B; Penugonda, Kavitha; Lindshield, Brian L

2016-01-01

Saw palmetto supplements (SPS) are commonly consumed by men with prostate cancer. We investigated whether SPS fatty acids and phytosterols concentrations determine their growth-inhibitory action in androgen-sensitive LNCaP cells and hamster flank organs. High long-chain fatty acids-low phytosterols (HLLP) SPS ≥ 750 nM with testosterone significantly increased and ≥500 nM with dihydrotestosterone significantly decreased LNCaP cell number. High long-chain fatty acids-high phytosterols (HLHP) SPS ≥ 500 nM with dihydrotestosterone and high medium-chain fatty acids-low phytosterols (HMLP) SPS ≥ 750 nM or with androgens significantly decreased LNCaP cell number (n = 3; p < 0.05). Five- to six-week-old, castrated male Syrian hamsters were randomized to control (n = 4), HLLP, HLHP, and HMLP SPS (n = 6) groups. Testosterone or dihydrotestosterone was applied topically daily for 21 days to the right flank organ; the left flank organ was treated with ethanol and served as the control. Thirty minutes later, SPS or ethanol was applied to each flank organ in treatment and control groups, respectively. SPS treatments caused a notable but nonsignificant reduction in the difference between left and right flank organ growth in testosterone-treated SPS groups compared to the control. The same level of inhibition was not seen in dihydrotestosterone-treated SPS groups (p < 0.05). Results may suggest that SPS inhibit 5α-reductase thereby preventing hamster flank organ growth.

Measuring the spectrum of mutation induced by nitrogen ions and protons in the human-hamster hybrid cell line A(L)C

NASA Technical Reports Server (NTRS)

Kraemer, S. M.; Kronenberg, A.; Ueno, A.; Waldren, C. A.; Chatterjee, A. (Principal Investigator)

2000-01-01

Astronauts can be exposed to charged particles, including protons, alpha particles and heavier ions, during space flights. Therefore, studying the biological effectiveness of these sparsely and densely ionizing radiations is important to understanding the potential health effects for astronauts. We evaluated the mutagenic effectiveness of sparsely ionizing 55 MeV protons and densely ionizing 32 MeV/nucleon nitrogen ions using cells of two human-hamster cell lines, A(L) and A(L)C. We have previously characterized a spectrum of mutations, including megabase deletions, in human chromosome 11, the sole human chromosome in the human-hamster hybrid cell lines A(L)C and A(L). CD59(-) mutants have lost expression of a human cell surface antigen encoded by the CD59 gene located at 11p13. Deletion of genes located on the tip of the short arm of 11 (11p15.5) is lethal to the A(L) hybrid, so that CD59 mutants that lose the entire chromosome 11 die and escape detection. In contrast, deletion of the 11p15.5 region is not lethal in the hybrid A(L)C, allowing for the detection of chromosome loss or other chromosomal mutations involving 11p15.5. The 55 MeV protons and 32 MeV/nucleon nitrogen ions were each about 10 times more mutagenic per unit dose at the CD59 locus in A(L)C cells than in A(L) cells. In the case of nitrogen ions, the mutations observed in A(L)C cells were predominantly due to chromosome loss events or 11p deletions, often containing a breakpoint in the pericentromeric region. The increase in the CD59(-) mutant fraction for A(L)C cells exposed to protons was associated with either translocation of portions of 11q onto a hamster chromosome, or discontinuous or "skipping" mutations. We demonstrate here that A(L)C cells are a powerful tool that will aid in the understanding of the mutagenic effects of different types of ionizing radiation.

Response to high LET radiation 12C (LET, 295 keV/microm) in M5 cells, a radio resistant cell strain derived from Chinese hamster V79 cells.

PubMed

Pathak, R; Sarma, A; Sengupta, B; Dey, S K; Khuda-Bukhsh, A R

2007-01-01

To study the effects of 12C-beam of 295 keV/microm (57.24 MeV) on M5 and Chinese hamster V79 cells by using cytogenetic assays like micronuclei (MN) induction, chromosomal aberrations (CA) and apoptosis. Additionally, the relative survival of these two cell lines was tested by the colony forming ability of the cells, with a view to understanding the mechanism of cellular damages that lead to difference in cell survival. Confluent cells were irradiated with 12C-beam at various doses using 15UD Pelletron accelerator. Cell survival was studied by the colony forming ability of cells. MN assay was done by fluorescent staining. Different types of chromosomal aberrations in metaphase cells were scored at 12 h after irradiation. Apoptosis was measured at different post irradiation times as detected by nuclear fragmentation and DNA ladder was prepared after 48 h of incubation. Dose-dependent decrease in surviving fractions was found in both the cell lines. However, the surviving fractions were higher in M5 cells in comparison to V79 cells when exposed to the same radiation doses. On the other hand, induced MN frequencies, CA frequencies and apoptosis percentages were less in M5 cells than V79 cells. Very good correlations between surviving fractions and induced MN frequencies or induced total CA or induced apoptosis percentages were obtained in this study. The cell strain M5 showed relatively more radio-resistance to 12C-beam compared to Chinese hamster V79 cells in this study. As the MN formation, CA and apoptosis induction were less in M5 cells as compared to parental V79 cells, the higher cell survival in the former could possibly be attributed to their better repairing ability leading to higher cell survival.

ULTRASTRUCTURE OF THE NUCLEOLUS DURING THE CHINESE HAMSTER CELL CYCLE

PubMed Central

Noel, J. S.; Dewey, W. C.; Abel, J. H.; Thompson, R. P.

1971-01-01

Changes in the structure of the nucleolus during the cell cycle of the Chinese hamster cell in vitro were studied. Quantitative electron microscopic techniques were used to establish the size and volume changes in nucleolar structures. In mitosis, nucleolar remnants, "persistent nucleoli," consisting predominantly of ribosome-like granular material, and a granular coating on the chromosomes were observed. Persistent nucleoli were also observed in some daughter nuclei as they were leaving telophase and entering G1. During very early G1, a dense, fibrous material characteristic of interphase nucleoli was noted in the nucleoplasm of the cells. As the cells progressed through G1, a granular component appeared which was intimately associated with the fibrous material. By the middle of G1, complete, mature nucleoli were present. The nucleolar volume enlarged by a factor of two from the beginning of G1 to the middle of S primarily due to the accumulation of the granular component. During the G2 period, there was a dissolution or breakdown of the nucleolus prior to the entry of the cells into mitosis. Correlations between the quantitative aspects of this study and biochemical and cytochemical data available in the literature suggest the following: nucleolar reformation following division results from the activation of the nucleolar organizer regions which transcribe for RNA first appearing in association with protein as a fibrous component (45S RNA) and then later as a granular component (28S and 32S RNA). PMID:4933472

Inhibition of apoptosis using exosomes in Chinese hamster ovary cell culture.

PubMed

Han, Seora; Rhee, Won Jong

2018-05-01

Animal cell culture technology for therapeutic protein production has shown significant improvement over the last few decades. Chinese hamster ovary (CHO) cells have been widely adapted for the production of biopharmaceutical drugs. In the biopharmaceutical industry, it is crucial to develop cell culture media and culturing conditions to achieve the highest productivity and quality. However, CHO cells are significantly affected by apoptosis in the bioreactors, resulting in a substantial decrease in product quantity and quality. Thus, to overcome the obstacle of apoptosis in CHO cell culture, it is critical to develop a novel method that does not have minimal concern of safety or cost. Herein, we showed for the first time that exosomes, which are nano-sized extracellular vesicles, derived from CHO cells inhibited apoptosis in CHO cell culture when supplemented to the culture medium. Flow cytometric and microscopic analyses revealed that substantial amounts of exosomes were delivered to CHO cells. Higher cell viability after staurosporine treatment was observed by exosome supplementation (67.3%) as compared to control (41.1%). Furthermore, exosomes prevented the mitochondrial membrane potential loss and caspase-3 activation, meaning that the exosomes enhanced cellular activities under pro-apoptotic condition. As the exosomes supplements are derived from CHO cells themselves, it is not only beneficial for the biopharmaceutical productivity of CHO cell culture to inhibit apoptosis, but also from a regulatory standpoint to diminish any safety concerns. Thus, we conclude that the method developed in this research may contribute to the biopharmaceutical industry where minimizing apoptosis in CHO cell culture is beneficial. © 2018 Wiley Periodicals, Inc.

Zika virus infection of adult and fetal STAT2 knock-out hamsters.

PubMed

Siddharthan, Venkatraman; Van Wettere, Arnaud J; Li, Rong; Miao, Jinxin; Wang, Zhongde; Morrey, John D; Julander, Justin G

2017-07-01

Zika virus (ZIKV) infection was investigated in adult and fetal STAT2 knock-out (KO) hamsters. Subcutaneous injection of ZIKV of adults resulted in morbidity, mortality, and infection of the uterus, placenta, brain, spinal cord, and testicles, thus providing an opportunity to evaluate congenital ZIKV infection in a second rodent species besides mice. ZIKV-infected cells with morphologies of Sertoli cells and spermatogonia were observed in the testes, which may have implications for sexual transmission and male sterility. Neonates exposed as fetuses to ZIKV at 8 days post-coitus were not smaller than controls. Nevertheless, infectious virus and ZIKV RNA was detected in some, but not all, placentas and fetal brains of KO hamsters. STAT2 KO hamsters may be useful for addressing sexual transmission, pathogenesis, routes of fetal infection, and neurological disease outcomes, and may also be used in antiviral or vaccine studies to identify intervention strategies. Copyright © 2017. Published by Elsevier Inc.

Male hamster preference for odors of female hamster vaginal discharges: studies of experiential and hormonal determinants.

PubMed

Gregory, E; Engel, K; Pfaff, D

1975-07-01

Male hamsters approach sources of odors from female hamster vaginal discharges and spend significantly more time around these odor sources than around control locations in the test box. This preference for female hamster vaginal odors appears in sexually inexperienced as well as experienced males, even in individuals isolated from females since the time of weaning. Castration significantly reduces the sex odor preference, and treatment with testosterone propionate partially restores it.

Pleural lesions in Syrian golden hamsters and Fischer-344 rats following intrapleural instillation of man-made ceramic or glass fibers.

PubMed

Everitt, J I; Bermudez, E; Mangum, J B; Wong, B; Moss, O R; Janszen, D; Rutten, A A

1994-01-01

The mesothelium is a target of the toxic and carcinogenic effects of certain natural mineral and man-made fibers. Long-term inhalation of a ceramic fiber (RCF-1) results in a high incidence of pleural mesotheliomas in Syrian golden hamsters but not in identically exposed Fischer-344 rats. The present study compared the histopathology of the early pleural response in rats and hamsters instilled with artificial fibers. Groups of Syrian golden hamsters and Fischer-344 rats were instilled with ceramic (RCF-1) or glass (MMVF-10) fibers directly into the pleural space. Each species received approximately equal numbers of long, thin fibers per g body weight. Fiber-induced lesions were compared 7 and 28 days postinstillation. Both hamsters and rats developed qualitatively similar dose-dependent inflammatory lesions that were not fiber-type specific. Both species developed fibrosis in conjunction with inflammation in the visceral pleura, but a striking interspecies difference was noted in the pattern of mesothelial cell response. Hamsters developed greater surface mesothelial cell proliferation and had focal aggregates of mesothelial cells embedded deep within regions of visceral pleural fibrosis. It is hypothesized from the present study that the marked fiber-induced proliferative mesothelial cell response of the hamster visceral pleura may explain the high number of pleural mesotheliomas found in long-term fiber studies in this species.

Ionotropic glutamate receptor GluR2/3-immunoreactive neurons in the cat, rabbit, and hamster superficial superior colliculus.

PubMed

Park, Won-Mee; Kim, Min-Jeong; Jeon, Chang-Jin

2004-06-01

Ionotropic glutamate receptor (GluR) subtypes occur in various types of cells in the central nervous system. We studied the distribution of AMPA glutamate receptor subtype GluR2/3 in the superficial layers of cat, rabbit, and hamster superior colliculus (SC) with antibody immunocytochemistry and the effect of enucleation on this distribution. Furthermore, we compared this labeling to that of calbindin D28K and parvalbumin. Anti-GluR2/3-immunoreactive (IR) cells formed a dense band of labeled cells within the lower superficial gray layer (SGL) and upper optic layer (OL) in the cat SC. By contrast, GluR2/3-IR cells formed a dense band within the upper OL in the rabbit and within the OL in the hamster SC. Calbindin D28K-IR cells are located in three layers in the SC: one within the zonal layer (ZL) and the upper SGL in all three animals, a second within the lower OL and upper IGL in the cat, within the IGL in the rabbit and within the OL in the hamster, and a third within the deep gray layer (DGL) in all three animals. Many parvalbumin-IR neurons were found within the lower SGL and upper OL. Thus, the GluR2/3-IR band was sandwiched between the first and second layers of calbindin D28K-IR cells in the cat and rabbit SC while the distribution of GluR2/3-IR cells in the hamster matches the second layer of calbindin D28K-IR cells. The patterned distribution of GluR2/3-IR cells overlapped the tier of parvalbumin-IR neurons in cat, but only partially overlapped in hamster and rabbit. Two-color immunofluorescence revealed that more than half (55.1%) of the GluR2/3-IR cells in the hamster SC expressed calbindin D28K. By contrast, only 9.9% of GluR2/3-IR cells expressed calbindin D28K in the cat. Double-labeled cells were not found in the rabbit SC. Some (4.8%) GluR2/3-IR cells in the cat SC also expressed parvalbumin, while no GluR2/3-IR cells in rabbit and hamster SC expressed parvalbumin. In this dense band of GluR2/3, the majority of labeled cells were small to medium

Intestinal transfer of choline in rat and hamster

PubMed Central

Sanford, P. A.; Smyth, D. H.

1971-01-01

1. The transfer of choline was studied with sacs of everted intestine of rat and hamster. 2. The choline transfer can be divided into two components, a diffusion process and a saturable process. The latter plays a relatively greater part at low concentrations of choline, which include the physiological concentration in the plasma. The saturable process is better seen in the hamster than in the rat. 3. Intestinal transfer of choline is influenced by substances altering the availability of energy in the cell, and by some substances chemically or pharmacologically related to choline. These findings are consistent with some kind of specific mechanism for choline transfer. 4. Part of the choline taken up by the cell appears as a metabolite not yet identified. The formation of the metabolite is a saturable process and is abolished by anaerobic conditions and by homogenization. 5. The results are also discussed in relation to parameters of transfer. PMID:5090994

Molecular Prerequisites for Diminished Cold Sensitivity in Ground Squirrels and Hamsters.

PubMed

Matos-Cruz, Vanessa; Schneider, Eve R; Mastrotto, Marco; Merriman, Dana K; Bagriantsev, Sviatoslav N; Gracheva, Elena O

2017-12-19

Thirteen-lined ground squirrels and Syrian hamsters are known for their ability to withstand cold during hibernation. We found that hibernators exhibit cold tolerance even in the active state. Imaging and electrophysiology of squirrel somatosensory neurons reveal a decrease in cold sensitivity of TRPM8-expressing cells. Characterization of squirrel and hamster TRPM8 showed that the channels are chemically activated but exhibit poor activation by cold. Cold sensitivity can be re-introduced into squirrel and hamster TRPM8 by transferring the transmembrane domain from the cold sensitive rat ortholog. The same can be achieved in squirrel TRPM8 by mutating only six amino acids. Reciprocal mutations suppress cold sensitivity of the rat ortholog, supporting functional significance of these residues. Our results suggest that ground squirrels and hamsters exhibit reduced cold sensitivity, partially due to modifications in the transmembrane domain of TRPM8. Our study reveals molecular adaptations that accompany cold tolerance in two species of mammalian hibernators. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Cultured Chinese hamster cells undergo apoptosis after exposure to cold but nonfreezing temperatures.

PubMed

Nagle, W A; Soloff, B L; Moss, A J; Henle, K J

1990-08-01

Cultured Chinese hamster V79 fibroblast cells at the transition from logarithmic to stationary growth have been shown to undergo apoptosis (programmed cell death) after cold shock [B. L. Soloff, W. A. Nagle, A. J. Moss, Jr., K. J. Henle, and J. T. Crawford, Biochem. Biophys. Res. Commun. 145, 876-883 (1987)]. In this report, we show that about 95% of the cell population was susceptible to cold-induced apoptosis, and the amount of cell killing was dependent on the duration of hypothermia. Cells treated for 0-90 min at 0 degrees C exhibited an exponential survival curve with a D0 of 32 min; thus, even short exposures to the cold (e.g., 5 min) produced measurable cell killing. The cold-induced injury was not produced by freezing, because similar results were observed at 6 degrees C, and cell killing was not influenced by the cryoprotective agent dimethyl sulfoxide. Cold-induced apoptosis was inhibited by rewarming at 23 degrees C, compared to 37 degrees C, by inhibitors of macromolecular synthesis, such as cycloheximide, and by 0.8 mM zinc sulfate. The results suggest that apoptosis represents a new manifestation of cell injury after brief exposure to 0-6 degrees C hypothermia.

Centriole distribution during tripolar mitosis in Chinese hamster ovary cells

PubMed Central

1984-01-01

During bipolar mitosis a pair of centrioles is distributed to each cell but the activities of the two centrioles within the pair are not equivalent. The parent is normally surrounded by a cloud of pericentriolar material that serves as a microtubule-organizing center. The daughter does not become associated with pericentriolar material until it becomes a parent in the next cell cycle (Rieder, C.L., and G. G. Borisy , 1982, Biol. Cell., 44:117-132). We asked whether the microtubule-organizing activity associated with a centriole was dependent on its becoming a parent. We induced multipolar mitosis in Chinese hamster ovary cells by treatment with 0.04 micrograms/ml colcemid for 4 h. After recovery from this colcemid block, the majority of cells divided into two, but 40% divided into three and 2% divided into four. The tripolar mitotic cells were examined by antitubulin immunofluorescence and by high voltage electron microscopy of serial thick (0.25-micron) sections. The electron microscope analysis showed that centriole number was conserved and that the centrioles were distributed among the three spindle poles, generally in a 2:1:1 or 2:2:0 pattern. The first pattern shows that centriole parenting is not prerequisite for association with pole function; the second pattern indicates that centrioles per se are not required at all. However, the frequency of midbody formation and successful division was higher when centrioles were present in the 2:1:1 pattern. We suggest that the centrioles may help the proper distribution and organization of the pericentriolar cloud, which is needed for the formation of a functional spindle pole. PMID:6373793

Hypothalamic Ventricular Ependymal Thyroid Hormone Deiodinases Are an Important Element of Circannual Timing in the Siberian Hamster (Phodopus sungorus)

PubMed Central

Bolborea, Matei; Wilson, Dana; Mercer, Julian G.; Ebling, Francis J. P.; Morgan, Peter J.; Barrett, Perry

2013-01-01

Exposure to short days (SD) induces profound changes in the physiology and behaviour of Siberian hamsters, including gonadal regression and up to 30% loss in body weight. In a continuous SD environment after approximately 20 weeks, Siberian hamsters spontaneously revert to a long day (LD) phenotype, a phenomenon referred to as the photorefractory response. Previously we have identified a number of genes that are regulated by short photoperiod in the neuropil and ventricular ependymal (VE) cells of the hypothalamus, although their importance and contribution to photoperiod induced physiology is unclear. In this refractory model we hypothesised that the return to LD physiology involves reversal of SD expression levels of key hypothalamic genes to their LD values and thereby implicate genes required for LD physiology. Male Siberian hamsters were kept in either LD or SD for up to 39 weeks during which time SD hamster body weight decreased before increasing, after more than 20 weeks, back to LD values. Brain tissue was collected between 14 and 39 weeks for in situ hybridization to determine hypothalamic gene expression. In VE cells lining the third ventricle, expression of nestin, vimentin, Crbp1 and Gpr50 were down-regulated at 18 weeks in SD photoperiod, but expression was not restored to the LD level in photorefractory hamsters. Dio2, Mct8 and Tsh-r expression were altered by SD photoperiod and were fully restored, or even exceeded values found in LD hamsters in the refractory state. In hypothalamic nuclei, expression of Srif and Mc3r mRNAs was altered at 18 weeks in SD, but were similar to LD expression values in photorefractory hamsters. We conclude that in refractory hamsters not all VE cell functions are required to establish LD physiology. However, thyroid hormone signalling from ependymal cells and reversal of neuronal gene expression appear to be essential for the SD refractory response. PMID:23637944

Topological defects control collective dynamics in neural progenitor cell cultures

NASA Astrophysics Data System (ADS)

Kawaguchi, Kyogo; Kageyama, Ryoichiro; Sano, Masaki

2017-04-01

Cultured stem cells have become a standard platform not only for regenerative medicine and developmental biology but also for biophysical studies. Yet, the characterization of cultured stem cells at the level of morphology and of the macroscopic patterns resulting from cell-to-cell interactions remains largely qualitative. Here we report on the collective dynamics of cultured murine neural progenitor cells (NPCs), which are multipotent stem cells that give rise to cells in the central nervous system. At low densities, NPCs moved randomly in an amoeba-like fashion. However, NPCs at high density elongated and aligned their shapes with one another, gliding at relatively high velocities. Although the direction of motion of individual cells reversed stochastically along the axes of alignment, the cells were capable of forming an aligned pattern up to length scales similar to that of the migratory stream observed in the adult brain. The two-dimensional order of alignment within the culture showed a liquid-crystalline pattern containing interspersed topological defects with winding numbers of +1/2 and -1/2 (half-integer due to the nematic feature that arises from the head-tail symmetry of cell-to-cell interaction). We identified rapid cell accumulation at +1/2 defects and the formation of three-dimensional mounds. Imaging at the single-cell level around the defects allowed us to quantify the velocity field and the evolving cell density; cells not only concentrate at +1/2 defects, but also escape from -1/2 defects. We propose a generic mechanism for the instability in cell density around the defects that arises from the interplay between the anisotropic friction and the active force field.

Depletion of Alveolar Macrophages Does Not Prevent Hantavirus Disease Pathogenesis in Golden Syrian Hamsters.

PubMed

Hammerbeck, Christopher D; Brocato, Rebecca L; Bell, Todd M; Schellhase, Christopher W; Mraz, Steven R; Queen, Laurie A; Hooper, Jay W

2016-07-15

Andes virus (ANDV) is associated with a lethal vascular leak syndrome in humans termed hantavirus pulmonary syndrome (HPS). The mechanism for the massive vascular leakage associated with HPS is poorly understood; however, dysregulation of components of the immune response is often suggested as a possible cause. Alveolar macrophages are found in the alveoli of the lung and represent the first line of defense to many airborne pathogens. To determine whether alveolar macrophages play a role in HPS pathogenesis, alveolar macrophages were depleted in an adult rodent model of HPS that closely resembles human HPS. Syrian hamsters were treated, intratracheally, with clodronate-encapsulated liposomes or control liposomes and were then challenged with ANDV. Treatment with clodronate-encapsulated liposomes resulted in significant reduction in alveolar macrophages, but depletion did not prevent pathogenesis or prolong disease. Depletion also did not significantly reduce the amount of virus in the lung of ANDV-infected hamsters but altered neutrophil recruitment, MIP-1α and MIP-2 chemokine expression, and vascular endothelial growth factor (VEGF) levels in hamster bronchoalveolar lavage (BAL) fluid early after intranasal challenge. These data demonstrate that alveolar macrophages may play a limited protective role early after exposure to aerosolized ANDV but do not directly contribute to hantavirus disease pathogenesis in the hamster model of HPS. Hantaviruses continue to cause disease worldwide for which there are no FDA-licensed vaccines, effective postexposure prophylactics, or therapeutics. Much of this can be attributed to a poor understanding of the mechanism of hantavirus disease pathogenesis. Hantavirus disease has long been considered an immune-mediated disease; however, by directly manipulating the Syrian hamster model, we continue to eliminate individual immune cell types. As the most numerous immune cells present in the respiratory tract, alveolar macrophages are

Depletion of Alveolar Macrophages Does Not Prevent Hantavirus Disease Pathogenesis in Golden Syrian Hamsters

PubMed Central

Hammerbeck, Christopher D.; Brocato, Rebecca L.; Bell, Todd M.; Schellhase, Christopher W.; Mraz, Steven R.; Queen, Laurie A.

2016-01-01

ABSTRACT Andes virus (ANDV) is associated with a lethal vascular leak syndrome in humans termed hantavirus pulmonary syndrome (HPS). The mechanism for the massive vascular leakage associated with HPS is poorly understood; however, dysregulation of components of the immune response is often suggested as a possible cause. Alveolar macrophages are found in the alveoli of the lung and represent the first line of defense to many airborne pathogens. To determine whether alveolar macrophages play a role in HPS pathogenesis, alveolar macrophages were depleted in an adult rodent model of HPS that closely resembles human HPS. Syrian hamsters were treated, intratracheally, with clodronate-encapsulated liposomes or control liposomes and were then challenged with ANDV. Treatment with clodronate-encapsulated liposomes resulted in significant reduction in alveolar macrophages, but depletion did not prevent pathogenesis or prolong disease. Depletion also did not significantly reduce the amount of virus in the lung of ANDV-infected hamsters but altered neutrophil recruitment, MIP-1α and MIP-2 chemokine expression, and vascular endothelial growth factor (VEGF) levels in hamster bronchoalveolar lavage (BAL) fluid early after intranasal challenge. These data demonstrate that alveolar macrophages may play a limited protective role early after exposure to aerosolized ANDV but do not directly contribute to hantavirus disease pathogenesis in the hamster model of HPS. IMPORTANCE Hantaviruses continue to cause disease worldwide for which there are no FDA-licensed vaccines, effective postexposure prophylactics, or therapeutics. Much of this can be attributed to a poor understanding of the mechanism of hantavirus disease pathogenesis. Hantavirus disease has long been considered an immune-mediated disease; however, by directly manipulating the Syrian hamster model, we continue to eliminate individual immune cell types. As the most numerous immune cells present in the respiratory tract

A comparative genomic hybridization approach to study gene copy number variations among Chinese hamster cell lines.

PubMed

Vishwanathan, Nandita; Bandyopadhyay, Arpan; Fu, Hsu-Yuan; Johnson, Kathryn C; Springer, Nathan M; Hu, Wei-Shou

2017-08-01

Chinese Hamster Ovary (CHO) cells are aneuploid in nature. The genome of recombinant protein producing CHO cell lines continuously undergoes changes in its structure and organization. We analyzed nine cell lines, including parental cell lines, using a comparative genomic hybridization (CGH) array focused on gene-containing regions. The comparison of CGH with copy-number estimates from sequencing data showed good correlation. Hierarchical clustering of the gene copy number variation data from CGH data revealed the lineage relationships between the cell lines. On analyzing the clones of a clonal population, some regions with altered genomic copy number status were identified indicating genomic changes during passaging. A CGH array is thus an effective tool in quantifying genomic alterations in industrial cell lines and can provide insights into the changes in the genomic structure during cell line derivation and long term culture. Biotechnol. Bioeng. 2017;114: 1903-1908. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Regional assignment of seven genes on chromosome 1 of man by use of man-Chinese hamster somatic cell hybrids. I. Results obtained after hybridization of human cells carrying reciprocal translocations involving chromosome 1.

PubMed

Jongsma, A P; Burgerhout, W G

1977-01-01

Regional localization studies of genes coding for human PGD, PPH1, PGM1, UGPP, GuK1, Pep-C, and FH, which have been assigned to chromosome 1, were performed with man-Chinese hamster somatic cell hybrids, Informative hybrids that retained fragments of the human chromosome 1 were produced by fusion of hamster cells with human cells carrying reciprocal translocations involving chromosome 1. Analysis of the hybrids that retained one of the translocation chromosomes or de novo rearrangements involving the human 1 revealed the following gene positions: PGD and PPH1 in 1pter leads to 1p32, PGM1 in 1p32 leads to 1p22, UGPP and GuK1 in 1q21 leads to 1q42, FH in 1qter leads to 1q42, and Pep-C probably in 1q42.

Secondhand smoke induces hepatic apoptosis and fibrosis in hamster fetus.

PubMed

Huang, Chien-Wei; Horng, Chi-Ting; Huang, Chih-Yang; Cho, Ta-Hsiung; Tsai, Yi-Chang; Chen, Li-Jeng; Hsu, Tsai-Ching; Tzang, Bor-Show

2016-09-01

Secondhand smoke (SHS) is an important health issue worldwide. Inhaling SHS during pregnancy could cause abnormalities in the internal tissues of newborns, which may then impair fetal development and even cause severe intrauterine damage and perinatal death. However, the understanding of cytopathic mechanisms of SHS by maternal passive smoking on fetus liver during pregnancy is still limited. This study analyzed the effects of high-dose SHS (SHSH) on fetus liver using a maternal passive smoking animal model. Experiments showed that hepatic matrix metalloproteinase-9 activity and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling-positive cells were significantly increased in livers from fetuses of hamsters treated with SHSH. Similarly, expressions of both extrinsic and intrinsic apoptotic molecules were significantly higher in livers from fetuses of hamsters exposed to SHSH. Additionally, significantly increased inflammatory proteins, including transforming growth factor β, inducible nitric oxide synthase, and interleukin 1β, and fibrotic signaling molecules, including phosphorylated Smad2/3, SP1, and α-smooth muscle actin, were observed in the fetus livers from hamsters treated with SHSH. This study revealed that SHSH not only increased apoptosis through intrinsic and extrinsic pathways in the livers of fetuses from hamsters exposed to SHSH but also augmented hepatic fibrosis via Smad2/3 signaling. © The Author(s) 2015.

Evaluation of eight cephalosporins in hamster colitis model.

PubMed Central

Ebright, J R; Fekety, R; Silva, J; Wilson, K H

1981-01-01

Eight commonly used cephalosporins were evaluated in the hamster colitis mode. They were all found to cause hemorrhagic cecitis and death within 10 days of being given as subcutaneous or oral challenges. Necropsy findings were indistinguishable from clindamycin-induced cecitis. Bacteria-free cecal filtrate obtained from hamsters dying of cephalosporin-induced cecitis contained toxin similar or identical to hat produced by Clostridium difficile isolated from the cecum of a hamster. Daily oral administration of poorly absorbed cephalosporins protected hamsters from clindamycin-induced cecitis and death as long as the cephalosporins were continued. The absorbable cephalosporins were ineffective in protecting hamsters from clindamycin-induced cecitis. This difference probably relates to the lower concentrations of absorbable cephalosporins maintained in the ceca of the hamsters. The possible correlation of these findings to human cases of cephalosporin-induced pseudomembranous colitis is discussed. PMID:6973951

THE ACTION OF α-AMANITIN ON RNA SYNTHESIS IN CHINESE HAMSTER OVARY CELLS

PubMed Central

Kedinger, Claude; Simard, Rene

1974-01-01

α-Amanitin acts in vitro as a selective inhibitor of the nucleoplasmic form B RNA polymerases. Treatment of Chinese hamster ovary (CHO) cells with this drug leads principally to a severe fragmentation of the nucleoli. While the ultrastructural lesions induced by α-amanitin in CHO cells and in rat or mouse liver are quite similar, the results diverge concerning the effect on RNA synthesis. It has been shown that in rat or mouse liver α-amanitin blocks both extranucleolar and nucleolar RNA synthesis. Our autoradiographic and biochemical evidence indicates that in CHO cells high molecular weight extranucleolar RNA synthesis (HnRNA) is blocked by the α-amanitin treatment, whereas nucleolar RNA (preribosomal RNA) synthesis remains unaffected even several hours after the inhibition of extranucleolar RNA synthesis. Furthermore, the processing of this RNA as well as its transport to the cytoplasm seem only slightly affected by the treatment. Finally, under these conditions, the synthesis of the low molecular RNA species (4–5S) still occurs, though less actively. The results are interpreted as evidence for a selective impairment of HnRNA synthesis by α-amanitin in CHO cells. PMID:4474178

An Automated Classification Technique for Detecting Defects in Battery Cells

NASA Technical Reports Server (NTRS)

McDowell, Mark; Gray, Elizabeth

2006-01-01

Battery cell defect classification is primarily done manually by a human conducting a visual inspection to determine if the battery cell is acceptable for a particular use or device. Human visual inspection is a time consuming task when compared to an inspection process conducted by a machine vision system. Human inspection is also subject to human error and fatigue over time. We present a machine vision technique that can be used to automatically identify defective sections of battery cells via a morphological feature-based classifier using an adaptive two-dimensional fast Fourier transformation technique. The initial area of interest is automatically classified as either an anode or cathode cell view as well as classified as an acceptable or a defective battery cell. Each battery cell is labeled and cataloged for comparison and analysis. The result is the implementation of an automated machine vision technique that provides a highly repeatable and reproducible method of identifying and quantifying defects in battery cells.

Pharmacokinetics and pharmacodynamics of tetra(m-hydroxyphenyl)chlorin in the hamster cheek pouch tumor model: comparison with clinical measurements.

PubMed

Glanzmann, T; Forrer, M; Blant, S A; Woodtli, A; Grosjean, P; Braichotte, D; van den Bergh, H; Monnier, P; Wagnières, G

2000-08-01

The pharmacokinetics (PK) of the photosensitizer tetra(m-hydroxyphenyl)chlorin (mTHPC) was measured by optical fiber-based light-induced fluorescence spectroscopy (LIFS) in the normal and tumoral cheek pouch mucosa of 29 Golden Syrian hamsters with chemically induced squamous cell carcinoma. Similar measurements were carried out on the normal oral cavity mucosa of five patients up to 30 days after injection. The drug doses were between 0.15 and 0.3 mg per kg of body weight (mg/kg), and the mTHPC fluorescence in the tissue was excited at 420 nm. The PK in both human and hamster exhibited similar behavior although the PK in the hamster mucosa was slightly delayed in comparison with that of its human counterpart. The mTHPC fluorescence signal of the hamster mucosa was smaller than that of the human mucosa by a factor of about 3 for the same injected drug dose. A linear correlation was found between the fluorescence signal and the mTHPC dose in the range from 0.075 to 0.5 mg/kg at times between 8 and 96 h after injection. No significant selectivity in mTHPC fluorescence between the tumoral and normal mucosa of the hamsters was found at any of the applied conditions. The sensitivity of the normal and tumoral hamster cheek pouch mucosa to mTHPC photodynamic therapy as a function of the light dose was determined by light irradiation at 650 nm and 150 mW/cm2, 4 days after the injection of a drug dose of 0.15 mg/kg. These results were compared with irradiations of the normal oral and normal and tumoral bronchial mucosa of 37 patients under the same conditions. The reaction to PDT of both types of human mucosae was considerably stronger than that of the hamster cheek pouch mucosa. The sensitivity to PDT became comparable between hamster and human mucosa when the drug dose for the hamster was increased to 0.5 mg/kg. A significant therapeutic selectivity between the normal and neoplastic hamster cheek pouch was observed. Less selectivity was found following irradiations of

In vivo but not in vitro leptin enhances lymphocyte proliferation in Siberian hamsters (Phodopus sungorus).

PubMed

Demas, Gregory E

2010-04-01

Mounting an immune response requires a relatively substantial investment of energy and marked reductions in energy availability can suppress immune function and presumably increase disease susceptibility. We have previously demonstrated that a moderate reduction in energy stores by partial surgical lipectomy impairs humoral immunity of Siberian hamsters (Phodopus sungorus) and is mediated, in part, by changes in the adipose tissue hormone leptin. The goals of the present study were to assess the role of leptin in cell-mediated immunity and to determine if the potential effects of leptin on immunity are via the direct actions of this hormone on lymphocytes, or indirect, via the sympathetic nervous system (SNS). In Experiment 1, hamsters received osmotic minipumps containing either murine leptin (0.5 microl/h) or vehicle alone for 10 days and splenocyte proliferation in response to the T-cell mitogen Concanavalin A (Con A) was determined. In Experiment 2, Con A-induced splenocyte proliferation was tested in the presence or absence of leptin in vitro. In Experiment 3, exogenous leptin was administered to intact or sympathetically denervated hamsters. Hamsters treated with in vivo leptin displayed increased splenocyte proliferation compared with control hamsters receiving vehicle. In contrast, in vitro leptin had no effect on splenocyte proliferation. Sympathetic denervation attenuated, but did not block, leptin-induced increases in immunity. Taken together, these results are consistent with the idea that leptin can enhance cell-mediated immunity; the SNS appears to contribute, least in part, to leptin-induced increases in immunity. Importantly, these findings confirm previous studies that leptin serves as an important endocrine link between energy balance and immunity. (c) 2009 Elsevier Inc. All rights reserved.

Effects of red mold dioscorea on oral carcinogenesis in DMBA-induced hamster animal model.

PubMed

Hsu, Wei-Hsuan; Lee, Bao-Hong; Pan, Tzu-Ming

2011-06-01

Monascus-fermented products offer valuable therapeutic benefits and have been extensively used for centuries in East Asia. Dioscorea has been proved to have anti-cancer effect. The aim of this study is to investigate the anti-tumor ability of the ethanol extract of red mold dioscorea (RMDE) on 7,12-dimethyl-1,2-benz[a]anthracene (DMBA)-induced hamster buccal pouch carcinogenesis. We induced oral squamous cell carcinoma (OSCC) in the buccal pouch of male Syrian golden hamsters by painting with 0.5% DMBA three times a week for 14 weeks. From 9 to 14 weeks, a dose of 50, 100, and 200 mg RMDE per kg body weight were painting with the hamsters for 6 weeks on days alternate to the DMBA application. The results demonstrated that RMDE decreased nitric oxide (NO), reactive oxygen species (ROS), and prostaglandin E(2) (PGE(2)) overexpression in hamster buccal pouches in the DMBA treatment group and increased p53, serum tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) to significantly stimulate caspase-8 and -3 activities, indicating that RMDE reduced oxidative damage causing by DMBA and induced apoptosis in oral cancer cells. Therefore, RMDE may have therapeutic potentials against OSCC. Copyright © 2011 Elsevier Ltd. All rights reserved.

INGN 007, an oncolytic adenovirus vector, replicates in Syrian hamsters but not mice: comparison of biodistribution studies

PubMed Central

Ying, B; Toth, K; Spencer, JF; Meyer, J; Tollefson, AE; Patra, D; Dhar, D; Shashkova, EV; Kuppuswamy, M; Doronin, K; Thomas, MA; Zumstein, LA; Wold, WSM; Lichtenstein, DL

2012-01-01

Preclinical biodistribution studies with INGN 007, an oncolytic adenovirus (Ad) vector, supporting an early stage clinical trial were conducted in Syrian hamsters, which are permissive for Ad replication, and mice, which are a standard model for assessing toxicity and biodistribution of replication-defective (RD) Ad vectors. Vector dissemination and pharmacokinetics following intravenous administration were examined by real-time PCR in nine tissues and blood at five time points spanning 1 year. Select organs were also examined for the presence of infectious vector/virus. INGN 007 (VRX-007), wild-type Ad5 and AdCMVpA (an RD vector) were compared in the hamster model, whereas only INGN 007 was examined in mice. DNA of all vectors was widely disseminated early after injection, but decayed rapidly in most organs. In the hamster model, DNA of INGN 007 and Ad5 was more abundant than that of the RD vector AdCMVpA at early times after injection, but similar levels were seen later. An increased level of INGN 007 and Ad5 DNA but not AdCMVpA DNA in certain organs early after injection, and the presence of infectious INGN 007 and Ad5 in lung and liver samples at early times after injection, strongly suggests that replication of INGN 007 and Ad5 occurred in several Syrian hamster organs. There was no evidence of INGN 007 replication in mice. In addition to providing important information about INGN 007, the results underscore the utility of the Syrian hamster as a permissive immunocompetent model for Ad5 pathogenesis and oncolytic Ad vectors. PMID:19197322

INGN 007, an oncolytic adenovirus vector, replicates in Syrian hamsters but not mice: comparison of biodistribution studies.

PubMed

Ying, B; Toth, K; Spencer, J F; Meyer, J; Tollefson, A E; Patra, D; Dhar, D; Shashkova, E V; Kuppuswamy, M; Doronin, K; Thomas, M A; Zumstein, L A; Wold, W S M; Lichtenstein, D L

2009-08-01

Preclinical biodistribution studies with INGN 007, an oncolytic adenovirus (Ad) vector, supporting an early stage clinical trial were conducted in Syrian hamsters, which are permissive for Ad replication, and mice, which are a standard model for assessing toxicity and biodistribution of replication-defective (RD) Ad vectors. Vector dissemination and pharmacokinetics following intravenous administration were examined by real-time PCR in nine tissues and blood at five time points spanning 1 year. Select organs were also examined for the presence of infectious vector/virus. INGN 007 (VRX-007), wild-type Ad5 and AdCMVpA (an RD vector) were compared in the hamster model, whereas only INGN 007 was examined in mice. DNA of all vectors was widely disseminated early after injection, but decayed rapidly in most organs. In the hamster model, DNA of INGN 007 and Ad5 was more abundant than that of the RD vector AdCMVpA at early times after injection, but similar levels were seen later. An increased level of INGN 007 and Ad5 DNA but not AdCMVpA DNA in certain organs early after injection, and the presence of infectious INGN 007 and Ad5 in lung and liver samples at early times after injection, strongly suggests that replication of INGN 007 and Ad5 occurred in several Syrian hamster organs. There was no evidence of INGN 007 replication in mice. In addition to providing important information about INGN 007, the results underscore the utility of the Syrian hamster as a permissive immunocompetent model for Ad5 pathogenesis and oncolytic Ad vectors.

[Cardiac neuronal depopulation in hamsters (Mesocricetus auratus) chronically infected with Trypanosoma cruzi].

PubMed

Chapadeiro, E; Silva, E L; Silva, A C; Fernandes, P; Ramirez, L E

1999-01-01

The aim of this study was to obtain an experimental animal model of destruction of cardiac neurons in order to investigate the behavior of the cardiac nervous system of hamsters chronically infected with Trypanosoma cruzi. We counted the neuronal cells of the cardiac autonomic nervous plexus in hamsters inoculated with 35,000 blood forms of three different T. cruzi strains and killed 5, 8 and 10 months after infection. We showed for the first time severe neuronal destruction in an experimental animal model with characteristics similar to those observed in human Chagas'disease.

Expression and activity levels of chymase in mast cells of burn wound tissues increase during the healing process in a hamster model.

PubMed

Dong, Xianglin; Xu, Tao; Ma, Shaolin; Wen, Hao

2015-06-01

The present study aimed to investigate the changes in the expression levels and activity of mast cell chymase in the process of burn wound healing in a hamster model of deep second-degree burn. The hamster model was established by exposing a ~3 cm diameter area of bare skin to hot water (75°C) for 0, 6, 8, 10 or 12 sec. Tissue specimens were collected 24 h after burning and histological analysis revealed that hot water contact for 12 sec was required to produce a deep second-degree burn. Quantitative polymerase chain reaction and a radioimmunoassay were used to the determine changes in chymase mRNA expression levels and activity. The mRNA expression levels and activity of chymase were increased in the burn wound tissues when compared with the normal skin. However, no statistically significant differences were observed in mast cell chymase activity amongst the various post-burn stages. Chymase mRNA expression levels peaked at day 1 post-burn, subsequently decreasing at days 3 and 7 post-burn and finally increasing again at day 14 post-burn. In summary, a hamster model of deep second-degree burn can be created by bringing the skin into contact with water at 75°C for 12 sec. Furthermore, the mRNA expression levels and activity of chymase in the burn wound tissues increased when compared with those in normal skin tissues.

Expression and activity levels of chymase in mast cells of burn wound tissues increase during the healing process in a hamster model

PubMed Central

DONG, XIANGLIN; XU, TAO; MA, SHAOLIN; WEN, HAO

2015-01-01

The present study aimed to investigate the changes in the expression levels and activity of mast cell chymase in the process of burn wound healing in a hamster model of deep second-degree burn. The hamster model was established by exposing a ~3 cm diameter area of bare skin to hot water (75°C) for 0, 6, 8, 10 or 12 sec. Tissue specimens were collected 24 h after burning and histological analysis revealed that hot water contact for 12 sec was required to produce a deep second-degree burn. Quantitative polymerase chain reaction and a radioimmunoassay were used to the determine changes in chymase mRNA expression levels and activity. The mRNA expression levels and activity of chymase were increased in the burn wound tissues when compared with the normal skin. However, no statistically significant differences were observed in mast cell chymase activity amongst the various post-burn stages. Chymase mRNA expression levels peaked at day 1 post-burn, subsequently decreasing at days 3 and 7 post-burn and finally increasing again at day 14 post-burn. In summary, a hamster model of deep second-degree burn can be created by bringing the skin into contact with water at 75°C for 12 sec. Furthermore, the mRNA expression levels and activity of chymase in the burn wound tissues increased when compared with those in normal skin tissues. PMID:26136958

Damage and Repair of DNA in 5-Bromodeoxyuridine-Labeled Chinese Hamster Cells Exposed to Fluorescent Light

PubMed Central

Ben-Hur, E.; Elkind, M. M.

1972-01-01

Illumination of Chinese hamster cells with fluorescent light after 5-bromodeoxyuridine incorporation leads to extensive single-strand breakage in the DNA of the exposed cells. The rate of production of single-strand breaks is dependent on the extent to which thymine is replaced by 5-bromouracil. At least some of the breaks observed with alkaline gradients are probably produced in vivo and are probably not contingent upon alkaline hydrolysis since breakage can be demonstrated with neutral gradients also. Cells are able to rejoin most of the single-strand breaks within 60 min; however, damage to the DNA-containing material (the “complex”) initially released from cells is repaired more slowly. Cysteamine protects against single-strand breakage with a dose-modifying factor of 2.8. A comparison is made between the production of single-strand breaks by fluorescent light and X-rays, and the significance of such breaks relative to cell survival is discussed. PMID:5063839

Effect of caffeine on the ultraviolet light induction of SV40 virus from transformed hamster cells

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

Zamansky, G.B.; Kleinman, L.F.; Little, J.B.

1976-01-01

The effect of caffeine on the uv light induction of SV40 virus from two transformed hamster cell lines heterogeneous for the induction of infectious virus was studied. The amount of virus induced was significantly increased in both cell lines when exposure to uv light was followed by treatment with caffeine. Caffeine in the absence of uv irradiation did not stimulate virus induction, nor did it stimulate SV40 replication in a lytic infection. There was an apparent difference in the concentrations of caffeine which maximally stimulated SV40 virus induction in the two cell lines. This effect could not be explained bymore » differences in cell survival after exposure to uv light and caffeine. Since caffeine is known to cause the accumulation of gaps formed in DNA during postreplication repair of uv-irradiated rodent cells, our results support the hypothesis that the formation of gaps or breaks in DNA is an important early step in virus induction.« less

Topological defects in confined populations of spindle-shaped cells

NASA Astrophysics Data System (ADS)

Duclos, Guillaume; Erlenkämper, Christoph; Joanny, Jean-François; Silberzan, Pascal

2017-01-01

Most spindle-shaped cells (including smooth muscles and sarcomas) organize in vivo into well-aligned `nematic’ domains, creating intrinsic topological defects that may be used to probe the behaviour of these active nematic systems. Active non-cellular nematics have been shown to be dominated by activity, yielding complex chaotic flows. However, the regime in which live spindle-shaped cells operate, and the importance of cell-substrate friction in particular, remains largely unexplored. Using in vitro experiments, we show that these active cellular nematics operate in a regime in which activity is effectively damped by friction, and that the interaction between defects is controlled by the system’s elastic nematic energy. Due to the activity of the cells, these defects behave as self-propelled particles and pairwise annihilate until all displacements freeze as cell crowding increases. When confined in mesoscopic circular domains, the system evolves towards two identical +1/2 disclinations facing each other. The most likely reduced positions of these defects are independent of the size of the disk, the cells’ activity or even the cell type, but are well described by equilibrium liquid crystal theory. These cell-based systems thus operate in a regime more stable than other active nematics, which may be necessary for their biological function.

Characterization of prmt7alpha and beta isozymes from Chinese hamster cells sensitive and resistant to topoisomerase II inhibitors.

PubMed

Gros, Laurent; Renodon-Cornière, Axelle; de Saint Vincent, Bruno Robert; Feder, Marcin; Bujnicki, Janusz M; Jacquemin-Sablon, Alain

2006-11-01

By selection of genetic suppressor elements (GSEs) conferring resistance to topoisomerase II inhibitors in Chinese hamster cells (DC-3F), we identified a gene encoding two proteins of 78 and 82 kDa which belong to the protein arginine methyltransferase (PRMT) family. Down-regulation of these enzymes (named PRMT7alpha and beta), either induced by an antisense GSE or as observed in the 9-OH-ellipticine (9-OH-E) resistant mutant DC-3F/9-OH-E, was responsible for cell resistance to various DNA damaging agents. Alternative splicing alterations in the 5'-terminal region and changes of the polyadenylation site of PRMT7 mRNAs were observed in these resistant mutant cells. PRMT7alpha and beta are isoforms of a highly conserved protein containing two copies of a module common to all PRMTs, comprising a Rossmann-fold domain and a beta-barrel domain. The C-terminal repeat appears to be degenerate and catalytically inactive. PRMT7alpha and beta form homo- and hetero-dimers but differ by their sub-cellular localization and in vitro recognize different substrates. PRMT7beta was only observed in Chinese hamster cells while mouse 10T1/2 fibroblasts only contain PRMT7alpha. Surprisingly, in human cells the anti-PRMT7 antibody essentially recognized an approximately 37 kDa peptide, which is not formed during extraction, and a faint band at 78 kDa. Analysis of in vitro and in vivo methylation patterns in cell lines under- or over-expressing PRMT7alpha and beta detected a discrete number of proteins which methylation and/or expression are under the control of these enzymes.

Functional defect in regulatory T cells in myasthenia gravis

PubMed Central

Thiruppathi, Muthusamy; Rowin, Julie; Jiang, Qin Li; Sheng, Jian Rong; Prabhakar, Bellur S.; Meriggioli, Matthew N.

2012-01-01

Forkhead box P3 (FOXP3)+ is a transcription factor necessary for the function of regulatory T cells (Treg cells). Treg cells maintain immune homeostasis and self-tolerance, and play an important role in the prevention of autoimmune disease. Here, we discuss the role of Treg cells in the pathogenesis of myasthenia gravis (MG) and review evidence indicating that a significant defect in Treg cell in vitro suppressive function exists in MG patients, without an alteration in circulating frequency. This functional defect is associated with a reduced expression of key functional molecules such as FOXP3 on isolated Treg cells and appears to be more pronounced in immunosuppression-naive MG patients. In vitro administration of granulocyte-macrophage colony-stimulating factor (GM-CSF) enhanced the suppressive function of Treg cells and up-regulated FOXP3 expression. These findings indicate a clinically relevant Treg cell–intrinsic defect in immune regulation in MG that may reveal a novel therapeutic target. PMID:23252899

Induction of tissue transglutaminase by dexamethasone: its correlation to receptor number and transglutaminase-mediated cell death in a series of malignant hamster fibrosarcomas.

PubMed Central

Johnson, T S; Scholfield, C I; Parry, J; Griffin, M

1998-01-01

Treatment of the hamster fibrosarcoma cell lines (Met B, D and E) and BHK-21 hamster fibroblast cells with the glucocorticoid dexamethasone led to a powerful dose-dependent mRNA-synthesis-dependent increase in transglutaminase activity, which can be correlated with dexamethasone-responsive receptor numbers in each cell line. Increasing the number of dexamethasone-responsive receptors by transfection of cells with the HG1 glucocorticoid receptor protein caused an increase in transglutaminase activity that was proportional to the level of transfected receptor. In all experiments the levels of the tissue transglutaminase-mediated detergent-insoluble bodies was found to be comparable with increases in transglutaminase activity. Despite an increase in detergent-insoluble body formation, an increase in apoptosis as measured by DNA fragmentation was not found. Incubation of cells with the non-toxic competitive transglutaminase substrate fluorescein cadaverine led to the incorporation of this fluorescent amine into cellular proteins when cells were damaged after exposure to trypsin during cell passage. These cross-linked proteins containing fluorescein cadaverine were shown to be present in the detergent-insoluble bodies, indicating that the origin of these bodies is via activation of tissue transglutaminase after cell damage by trypsinization rather than apoptosis per se, since Met B cells expressing the bcl-2 cDNA were not protected from detergent-insoluble body formation. We describe a novel mechanism of cell death related to tissue transglutaminase expression and cell damage. PMID:9512467

Metabolic engineering of Chinese hamster ovary cells: Towards a bioengineered heparin

PubMed Central

Baik, Jong Youn; Gasimli, Leyla; Yang, Bo; Datta, Payel; Zhang, Fuming; Glass, Charles A.; Esko, Jeffrey D.; Linhardt, Robert J.; Sharfstein, Susan T.

2012-01-01

Heparin is the most widely used pharmaceutical to control blood coagulation in modern medicine. A health crisis that took place in 2008 led to a demand for production of heparin from non-animal sources. Chinese hamster ovary (CHO) cells, commonly used mammalian host cells for production of foreign pharmaceutical proteins in the biopharmaceutical industry, are capable of producing heparan sulfate (HS), a related polysaccharide naturally. Since heparin and HS share the same biosynthetic pathway, we hypothesized that heparin could be produced in CHO cells by metabolic engineering. Based on the expression of endogenous enzymes in the HS / heparin pathways of CHO-S cells, human N-deacetylase/N-sulfotransferase (NDST2) and mouse heparan sulfate 3-O-sulfotransferase 1 (Hs3st1) genes were transfected sequentially into CHO host cells growing in suspension culture. Transfectants were screened using quantitative RT-PCR and Western blotting. Out of 120 clones expressing NDST2 and Hs3st1, 2 clones, Dual-3 and Dual-29, were selected for further analysis. An antithrombin III (ATIII) binding assay using flow cytometry, designed to recognize a key sugar structure characteristic of heparin, indicated that Hs3st1 transfection was capable of increasing ATIII binding. An anti-factor Xa assay, which affords a measure of anticoagulant activity, showed a significant increase in activity in the dual-expressing cell lines. Disaccharide analysis of the engineered HS showed a substantial increase in N-sulfo groups, but did not show a pattern consistent with pharmacological heparin, suggesting that further balancing the expression of transgenes with the expression levels of endogenous enzymes involved in HS / heparin biosynthesis might be necessary. PMID:22326251

Metabolic engineering of Chinese hamster ovary cells: towards a bioengineered heparin.

PubMed

Baik, Jong Youn; Gasimli, Leyla; Yang, Bo; Datta, Payel; Zhang, Fuming; Glass, Charles A; Esko, Jeffrey D; Linhardt, Robert J; Sharfstein, Susan T

2012-03-01

Heparin is the most widely used pharmaceutical to control blood coagulation in modern medicine. A health crisis that took place in 2008 led to a demand for production of heparin from non-animal sources. Chinese hamster ovary (CHO) cells, commonly used mammalian host cells for production of foreign pharmaceutical proteins in the biopharmaceutical industry, are capable of producing heparan sulfate (HS), a related polysaccharide naturally. Since heparin and HS share the same biosynthetic pathway, we hypothesized that heparin could be produced in CHO cells by metabolic engineering. Based on the expression of endogenous enzymes in the HS/heparin pathways of CHO-S cells, human N-deacetylase/N-sulfotransferase (NDST2) and mouse heparan sulfate 3-O-sulfotransferase 1 (Hs3st1) genes were transfected sequentially into CHO host cells growing in suspension culture. Transfectants were screened using quantitative RT-PCR and Western blotting. Out of 120 clones expressing NDST2 and Hs3st1, 2 clones, Dual-3 and Dual-29, were selected for further analysis. An antithrombin III (ATIII) binding assay using flow cytometry, designed to recognize a key sugar structure characteristic of heparin, indicated that Hs3st1 transfection was capable of increasing ATIII binding. An anti-factor Xa assay, which affords a measure of anticoagulant activity, showed a significant increase in activity in the dual-expressing cell lines. Disaccharide analysis of the engineered HS showed a substantial increase in N-sulfo groups, but did not show a pattern consistent with pharmacological heparin, suggesting that further balancing the expression of transgenes with the expression levels of endogenous enzymes involved in HS/heparin biosynthesis might be necessary. Copyright © 2012 Elsevier Inc. All rights reserved.

Histiocytic Sarcoma and Bilateral Facial Vein Thrombosis in a Siberian Hamster (Phodopus sungorus).

PubMed

Coble, Dondrae J; Shoemaker, Margaret; Harrington, Bonnie; Dardenne, Adrienne D; Bolon, Brad

2015-04-01

A 21-mo-old, male Siberian hamster (Phodopus sungorus) presented with left-sided facial swelling, proptosis of the left eye, and blepharospasm of the right eye. The hamster had been used only for breeding. Because of the poor prognosis, the hamster was euthanized without additional diagnostic assays or treatments. Routine gross pathologic evaluation demonstrated exophthalmos and presumptive hyphema of the left eye, bilateral facial edema, freely movable nodules within the mesentery, white foci within the liver, and a large mass effacing the cranial pole of the right kidney. On histologic evaluation, the mesenteric nodules and liver foci expressed histiocytic marker CD163 and thus were diagnosed as sites of histiocytic sarcoma, whereas the kidney mass was a well-differentiated renal cell carcinoma. The facial swelling resulted from bilateral, chronic, severe, branching thrombi in many facial veins. Additional age-related histopathologic findings were observed in other organs, including diffuse glomerulopathy, nesidioblastosis (pancreatic islet neoformation), and multiple foci of severe cartilage degeneration in the axial skeleton. To our knowledge, this report provides the first description of histiocytic sarcoma in a Siberian hamster.

Laguna Negra Virus Infection Causes Hantavirus Pulmonary Syndrome in Turkish Hamsters (Mesocricetus brandti).

PubMed

Hardcastle, K; Scott, D; Safronetz, D; Brining, D L; Ebihara, H; Feldmann, H; LaCasse, R A

2016-01-01

Laguna Negra virus (LNV) is a New World hantavirus associated with severe and often fatal cardiopulmonary disease in humans, known as hantavirus pulmonary syndrome (HPS). Five hamster species were evaluated for clinical and serologic responses following inoculation with 4 hantaviruses. Of the 5 hamster species, only Turkish hamsters infected with LNV demonstrated signs consistent with HPS and a fatality rate of 43%. Clinical manifestations in infected animals that succumbed to disease included severe and rapid onset of dyspnea, weight loss, leukopenia, and reduced thrombocyte numbers as compared to uninfected controls. Histopathologic examination revealed lung lesions that resemble the hallmarks of HPS in humans, including interstitial pneumonia and pulmonary edema, as well as generalized infection of endothelial cells and macrophages in major organ tissues. Histologic lesions corresponded to the presence of viral antigen in affected tissues. To date, there have been no small animal models available to study LNV infection and pathogenesis. The Turkish hamster model of LNV infection may be important in the study of LNV-induced HPS pathogenesis and development of disease treatment and prevention strategies. © The Author(s) 2015.

Mutagenic activities of heterocyclic amines in Chinese hamster lung cells in culture

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

Terada, M.; Nagao, M.; Nakayasu, M.

1986-01-01

A mutation assay system with Chinese hamster lung cells (CHL) using diphtheria toxin resistance as a selective marker has been established. The mutagenic activities of heterocyclic amines, originally isolated from pyrolyzates of amino acids and proteins, broiled fish and fried beef were assayed in cultured CHL cells in the absence and presence of a metabolic activation system, with diphtheria toxin resistance as a marker. All the heterocyclic amines tested except 3-amino-1,4-dimethyl-5H-pyrido (4,3-b)indole (Trp-P-1) required the presence of a metabolic activation system for mutagenicity on CHL cells. 3-Amino-1-methyl-5H-pyrido(4,3-b)indole (Trp-P-2) was the most mutagenic among the heterocyclic amines tested. Other compounds weremore » also mutagenic in the following order of decreasing potency: Trp-P-1, 2-amino-3,4-dimethylimidazo(4,5-f)quinoline (MeIQ), 2-amino-3-methylimidazo(4,5-f)quinoline (IQ), 2-amino-9H-pyrido(2,3-b)indole (A..cap alpha..C), 2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline (MeIQx), 2-amino-6-methyldipyrido(1,2-a:3',2'-d)imidazole (Glu-P-1) and 2-aminodipyrido(1,2--a:3',2'-d)imidazole (Glu-P-2).« less

Heat-resistant variants of the Chinese hamster ovary cell: alteration of cellular structure and expression of vimentin.

PubMed

Lee, Y J; Hou, Z Z; Curetty, L; Armour, E P; al-Saadi, A; Bernstein, J; Corry, P M

1992-04-01

Three heat-resistant mutant cell lines (78-1, 78-2, 78-3) were previously selected from Chinese hamster ovary cells. In this study, we investigated whether the differences in intrinsic thermal sensitivity result from alteration of stress protein levels or cellular structural changes. Although there was no significant difference in the levels of stress proteins, i.e., constitutive HSP70 in wild type and three heat-resistant mutant strains, there were marked differences in the amounts of vimentin among the cell lines. Two-dimensional gel electrophoresis and Western blot showed a 2.3-2.9-fold increase in the level of vimentin in the mutant cells under normal growth conditions. Northern blot also revealed higher amounts of vimentin mRNA in the mutant cells. Electron microscopy and immunofluorescence suggest that increased amounts of the vimentin-containing intermediate filaments are correlated with the heat-resistant phenotypes.

Stable expression of rat cytochrome P-450IIB1 cDNA in Chinese hamster cells (V79) and metabolic activation of aflatoxin B1.

PubMed Central

Doehmer, J; Dogra, S; Friedberg, T; Monier, S; Adesnik, M; Glatt, H; Oesch, F

1988-01-01

V79 Chinese hamster fibroblasts are widely used for mutagenicity testing but have the serious limitation that they do not express cytochromes P-450, which are needed for the activation of many promutagens to mutagenic metabolites. A full-length cDNA clone encoding the monooxygenase cytochrome P-450IIB1 under control of the simian virus 40 early promoter was constructed and cointroduced with the selection marker neomycin phosphotransferase (conferring resistance to G418) into V79 Chinese hamster cells. G418-resistant cells were selected, established as cell lines, and tested for cytochrome P-450IIB1 expression and enzymatic activity. Two cell lines (SD1 and SD3) were found that stably produce cytochrome P-450IIB1. Although purified cytochromes P-450 possess monooxygenase activity only after reconstitution with cytochrome P-450 reductase and phospholipid, the gene product of the construct exhibited this activity. This implies that the gene product is intracellularly localized in a way that allows access to the required components. If compared with V79 cells, the mutation rate for the hypoxanthine phosphoribosyltransferase (HPRT) locus in SD1 cells is markedly increased when exposed to aflatoxin B1, which is activated by this enzyme. Images PMID:3137560

Structural changes in plasma membranes prepared from irradiated Chinese hamster V79 cells as revealed by Raman spectroscopy

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

Verma, S.P.; Sonwalkar, N.

1991-04-01

The effect of gamma irradiation on the integrity of plasma membranes isolated from Chinese hamster V79 cells was investigated by Raman spectroscopy. Plasma membranes of control V79 cells show transitions between {minus}10 and 5{degree}C (low-temperature transition), 10 and 22{degree}C (middle-temperature transition), and 32 and 40{degree}C (high-temperature transition). Irradiation (5 Gy) alters these transitions markedly. First, the low-temperature transition shifts to higher temperature (onset and completion temperatures 4 and 14{degree}C). Second, the middle-temperature transition shifts up to the range of about 20-32{degree}C, but the width remains unchanged. Third, the higher temperature transition broadens markedly and shifts to the range of aboutmore » 15-40{degree}C. Protein secondary structure as determined by least-squares analysis of the amide I bands shows 36% total helix, 55% total beta-strand, and 9% turn plus undefined for control plasma membrane proteins. Plasma membrane proteins of irradiated V79 cells show an increase in total helix (40 and 45% at 5 and 10 Gy, respectively) and a decrease in the total beta-strand (48 and 44% at 5 and 10 Gy, respectively) structures. The qualitative analysis of the Raman features of plasma membranes and model compounds in the 1600 cm-1 region, assigned to tyrosine groups, revealed that irradiation alters the microenvironment of these groups. We conclude that the radiation dose used in the survival range of Chinese hamster V79 cells can cause damage to plasma membrane proteins without detectable lipid peroxidation, and that the altered proteins react differently with lipids, yielding a shift in the thermal transition properties.« less

Cultivation of recombinant Chinese hamster ovary cells grown as suspended aggregates in stirred vessels.

PubMed

Han, Yi; Liu, Xing-Mao; Liu, Hong; Li, Shi-Chong; Wu, Ben-Chuan; Ye, Ling-Ling; Wang, Qu-Wei; Chen, Zhao-Lie

2006-11-01

Recombinant Chinese hamster ovary (rCHO) cells capable of producing a prourokinase mutant (mPro-uk) grown as suspended aggregates in stirred vessels were described and characterized. The addition of chitosan to a mixture of DMEM and Ham's F12 (D-MEM/F-12) medium promoted cell aggregation and spheroid formation efficiently. Multicellular aggregates formed immediately after the rCHO cells were inoculated into the chitosan-added medium, and the mean diameter of the cell aggregates reflecting the aggregate size increased with culture time, shifting from 65 to 163 mum after 2 and 9 d of culture in spinner flasks. No significant difference in the metabolism performance of the rCHO cells was observed between suspended aggregates and anchored monolayers. However, the cells cultured as suspended aggregates showed a marked decrease in growth rate as evaluated from specific growth rate (mu). Replacing D-MEM/F-12 medium with CD 293 medium caused compact spherical cell aggregates to dissociate into small irregular aggregates and single cells without apparent effects on cell performance in subcultures. The perfusion culture of the rCHO cells grown as suspended aggregates in a 2-l stirred tank bioreactor for 15 d resulted in a maximum viable cell density of 5.6 x 10(6) cells ml(-1) and an mPro-uk concentration of about 2.6 x 10(3) IU ml(-1), and cell viability was remained at roughly 90% during the entire run.

Neurogenesis and ontogeny of specific cell phenotypes within the hamster suprachiasmatic nucleus.

PubMed

Antle, Michael C; LeSauter, Joseph; Silver, Rae

2005-06-09

The hamster suprachiasmatic nucleus (SCN) is anatomically and functionally heterogeneous. A group of cells in the SCN shell, delineated by vasopressin-ergic neurons, are rhythmic with respect to Period gene expression and electrical activity but do not receive direct retinal input. In contrast, some cells in the SCN core, marked by neurons containing calbindin-D28k, gastrin-releasing peptide (GRP), substance P (SP), and vasoactive intestinal polypeptide (VIP), are not rhythmic with respect to Period gene expression and electrical activity but do receive direct retinal input. Examination of the timing of neurogenesis using bromodeoxyuridine indicates that SCN cells are born between embryonic day 9.5 and 12.5. Calbindin, GRP, substance P, and VIP cells are born only during early SCN neurogenesis, between embryonic days 9.5-11.0. Vasopressin cells are born over the whole period of SCN neurogenesis, appearing as late as embryonic day 12.5. Examination of the ontogeny of peptide expression in these cell types reveals transient expression of calbindin in a cluster of dorsolateral SCN cells on postnatal days 1-2. The adult pattern of calbindin expression is detected in a different ventrolateral cell cluster starting on postnatal day 2. GRP and SP expression appear on postnatal day 8 and 10, respectively, after the retinohypothalamic tract has innervated the SCN. In summary, the present study describes the ontogeny-specific peptidergic phenotypes in the SCN and compares these developmental patterns to previously identified patterns in the appearance of circadian functions. These comparisons suggest the possibility that these coincident appearances may be causally related, with the direction of causation to be determined.

Selenite restores Pax6 expression in neuronal cells of chronically arsenic-exposed Golden Syrian hamsters.

PubMed

Aguirre-Vázquez, Alain; Sampayo-Reyes, Adriana; González-Escalante, Laura; Hernández, Alba; Marcos, Ricard; Castorena-Torres, Fabiola; Lozano-Garza, Gerardo; Taméz-Guerra, Reyes; de León, Mario Bermúdez

2017-01-01

Arsenic is a worldwide environmental pollutant that generates public health concerns. Various types of cancers and other diseases, including neurological disorders, have been associated with human consumption of arsenic in drinking water. At the molecular level, arsenic and its metabolites have the capacity to provoke genome instability, causing altered expression of genes. One such target of arsenic is the Pax6 gene that encodes a transcription factor in neuronal cells. The aim of this study was to evaluate the effect of two antioxidants, α-tocopheryl succinate (α-TOS) and sodium selenite, on Pax6 gene expression levels in the forebrain and cerebellum of Golden Syrian hamsters chronically exposed to arsenic in drinking water. Animals were divided into six groups. Using quantitative real-time reverse transcriptase (RT)-PCR analysis, we confirmed that arsenic downregulates Pax6 expression in nervous tissues by 53 ± 21% and 32 ± 7% in the forebrain and cerebellum, respectively. In the presence of arsenic, treatment with α-TOS did not modify Pax6 expression in nervous tissues; however, sodium selenite completely restored Pax6 expression in the arsenic-exposed hamster forebrain, but not the cerebellum. Although our results suggest the use of selenite to restore the expression of a neuronal gene in arsenic-exposed animals, its use and efficacy in the human population require further studies.

Transgene Expression and Host Cell Responses to Replication-Defective, Single-Cycle, and Replication-Competent Adenovirus Vectors.

PubMed

Crosby, Catherine M; Barry, Michael A

2017-02-18

Most adenovirus (Ad) vectors are E1 gene deleted replication defective (RD-Ad) vectors that deliver one transgene to the cell and all expression is based on that one gene. In contrast, E1-intact replication-competent Ad (RC-Ad) vectors replicate their DNA and their transgenes up to 10,000-fold, amplifying transgene expression markedly higher than RD-Ad vectors. While RC-Ad are more potent, they run the real risk of causing adenovirus infections in vector recipients and those that administer them. To gain the benefits of transgene amplification, but avoid the risk of Ad infections, we developed "single cycle" Ad (SC-Ad) vectors. SC-Ads amplify transgene expression and generated markedly stronger and more persistent immune responses than RD-Ad as expected. However, they also unexpectedly generated stronger immune responses than RC-Ad vectors. To explore the basis of this potency here, we compared gene expression and the cellular responses to infection to these vectors in vitro and in vivo. In vitro, in primary human lung epithelial cells, SC- and RC-Ad amplified their genomes more than 400-fold relative to RD-Ad with higher replication by SC-Ad. This replication translated into higher green fluorescent protein (GFP) expression for 48 h by SC- and RC-Ad than by RD-Ad. In vitro, in the absence of an immune system, RD-Ad expression became higher by 72 h coincident with cell death mediated by SC- and RC-Ad and release of transgene product from the dying cells. When the vectors were compared in human THP-1 Lucia- interferon-stimulated gene (ISG) cells, which are a human monocyte cell line that have been modified to quantify ISG activity, RC-Ad6 provoked significantly stronger ISG responses than RD- or SC-Ad. In mice, intravenous or intranasal injection produced up to 100-fold genome replication. Under these in vivo conditions in the presence of the immune system, luciferase expression by RC and SC-Ad was markedly higher than that by RD-Ad. In immunodeficient mice, SC

Parent-of-origin growth effects and the evolution of hybrid inviability in dwarf hamsters.

PubMed

Brekke, Thomas D; Good, Jeffrey M

2014-11-01

Mammalian hybrids often show abnormal growth, indicating that developmental inviability may play an important role in mammalian speciation. Yet, it is unclear if this recurrent phenotype reflects a common genetic basis. Here, we describe extreme parent-of-origin-dependent growth in hybrids from crosses between two species of dwarf hamsters, Phodopus campbelli and Phodopus sungorus. One cross type resulted in massive placental and embryonic overgrowth, severe developmental defects, and maternal death. Embryos from the reciprocal cross were viable and normal sized, but adult hybrid males were relatively small. These effects are strikingly similar to patterns from several other mammalian hybrids. Using comparative sequence data from dwarf hamsters and several other hybridizing mammals, we argue that extreme hybrid growth can contribute to reproductive isolation during the early stages of species divergence. Next, we tested if abnormal growth in hybrid hamsters was associated with disrupted genomic imprinting. We found no association between imprinting status at several candidate genes and hybrid growth, though two interacting genes involved in embryonic growth did show reduced expression in overgrown hybrids. Collectively, our study indicates that growth-related hybrid inviability may play an important role in mammalian speciation but that the genetic underpinnings of these phenotypes remain unresolved. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Circadian rhythms accelerate wound healing in female Siberian hamsters

PubMed Central

Cable, Erin J.; Onishi, Kenneth G.; Prendergast, Brian J.

2017-01-01

Circadian rhythms (CRs) provide temporal regulation and coordination of numerous physiological traits, including immune function. CRs in multiple aspects of immune function are absent in rodents that have been rendered circadian-arrhythmic through various methods. In Siberian hamsters, circadian arrhythmia can be induced by disruptive light treatments (DPS). Here we examined CRs in wound healing, and the effects of circadian disruption on wound healing in DPS-arrhythmic hamsters. Circadian entrained/rhythmic (RHYTH) and behaviorally-arrhythmic (ARR) female hamsters were administered a cutaneous wound either 3 h after light onset (ZT03) or 2 h after dark onset (ZT18); wound size was quantified daily using image analyses. Among RHYTH hamsters, ZT03 wounds healed faster than ZT18 wounds, whereas in ARR hamsters, circadian phase did not affect wound healing. In addition, wounds healed slower in ARR hamsters. The results document a clear CR in wound healing, and indicate that the mere presence of organismal circadian organization enhances this aspect of immune function. Faster wound healing in CR-competent hamsters may be mediated by CR-driven coordination of the temporal order of mechanisms (inflammation, leukocyte trafficking, tissue remodeling) underlying cutaneous wound healing. PMID:27998755

Heterogeneity within populations of recombinant Chinese hamster ovary cells expressing human interferon-gamma.

PubMed

Coppen, S R; Newsam, R; Bull, A T; Baines, A J

1995-04-20

The Chinese hamster ovary (CHO) cell line has great commercial importance in the production of recombinant human proteins, especially those for therapeutic use. Much attention has been paid to CHO cell population physiology in order to define factors affecting product fidelity and yield. Such studies have revealed that recombinant proteins, including human interferon-gamma (IFN-gamma), can be heterogeneous both in glycosylation and in proteolytic processing. The type of heterogeneity observed depends on the growth physiology of the cell population, although the relationship between them is complex. In this article we report results of a cytological study of the CHO320 line which expresses recombinant human IFN-gamma. When grown in suspension culture, this cell line exhibited three types of heterogeneity: (1) heterogeneity of the production of IFN-gamma within the cell population, (2) heterogeneity of the number of nuclei and mitotic spindles in dividing cells, and (3) heterogeneity of cellular environment. The last of these arises from cell aggregates which form in suspension culture: Some cells are exposed to the culture medium; others are fully enclosed within the mass with little or no direct access to the medium. Thus, live cells producing IFN-gamma are heterogeneous in their environment, with variable access to O(2) and nutrients. Within the aggregates, it appears that live cells proliferate on a dead cell mass. The layer of live cells can be several cells deep. Specific cell-cell attachments are observed between the living cells in these aggregates. Two proteins, known to be required for the formation of certain types of intercellular junctions, spectrin and vinculin, have been localized to the regions of cell-cell contact. The aggregation of the cells appears to be an active process requiring protein synthesis. (c) 1995 John Wiley & Sons, Inc.

V79 Chinese-hamster cells rendered resistant to high cadmium concentration also become resistant to oxidative stress.

PubMed Central

Mello-Filho, A C; Chubatsu, L S; Meneghini, R

1988-01-01

Chinese hamster cells (V79) resistant to high concentrations of Cd2+ in the medium were obtained by using the procedure of Beach & Palmiter [(1981) Proc. Natl. Acad. Sci. U.S.A. 78, 2110-2114], which in mouse led to amplification of metallothionein (MT) genes and to an enrichment in cellular MT. The Cd-resistant V79 clones isolated were significantly more resistant than parental cells to oxidative stress by extracellular H2O2 or a mixture of H2O2 and superoxide anion (O2-) generated by xanthine oxidase plus acetaldehyde. On a per-cell basis, there was no difference between the two cells in their total H2O2-decomposing or O2-(-)dismutating activity. The most likely explanation is that an enrichment in MT content in the Cd-resistant cells was responsible for this effect, because of the antioxidant properties already described for this protein. Images Fig. 2. PMID:2851992

EMODIN EFFICACY ON THE AKT, MAPK, ERK AND DNMT EXPRESSION PATTERN DURING DMBA-INDUCED ORAL CARCINOMA IN GOLDEN SYRIAN HAMSTERS.

PubMed

Manimaran, Asokan; Manoharan, Shanmugam; Neelakandan, Mani

2016-01-01

The present study has evaluated the Emodin efficacy on the Akt, MAPK, ERK and DNMT expression pattern during 7,12-dimethylbenz[a]anthracene (DMBA)-induced oral carcinoma in golden Syrian hamsters, in order to explore its antitumor potential. Oral tumors were developed in the buccal pouches of golden Syrian hamsters using the carcinogen, DMBA. While the incidence of tumor formation was 100% in hamsters treated with DMBA alone, the tumor formation was not noticed in DMBA+ Emodin treated hamsters. Also, Emodin reduced the severity of precancerous pathological lesions such as dysplasia, in the hamsters treated with DMBA. Emodin administration corrected the abnormalities in the expression pattern of Akt, MAPK, ERK and DNMT in the buccal mucosa of hamsters treated with DMBA. The present study thus suggests that the tumor preventive potential of Emodin is partly related to its modulating effect on the Akt, MAPK, ERK and DNMT expression pattern, as these molecular markers have a pivotal role in the process of cell proliferation, inflammation, invasion, and apoptosis.

Functional antigen binding by the defective B cells of CBA/N mice.

PubMed

Snippe, H; Merchant, B; Lizzio, E F; Inman, J K

1982-01-01

CBA/N mice have an X-linked B cell defect which prevents them from responding to nonmitogenic thymic independent (TI-2) antigens such as dinitrophenylated DNP-Ficoll (1,2). The F1 male progeny of CBA/N female mice express the same defect. Spleen cell suspensions from such defective mice (CBA/N X C3H/HeN F1 males) could not respond to DNP-Ficoll following in vitro immunization and subsequent transfer into irradiated, syngeneic, F1 male recipients as expected. In contrast, normal CBA/N X C3H/HeN F1 female spleen cells could respond and effect a "rescue"; they mounted strong plaque-forming cell responses 7 days after in vitro exposure to DNP-Ficoll and subsequent transfer into irradiated F1 male recipients. Defective F1 male spleen cells, however, could bind significant quantities of 125I-DNP-Ficoll after in vitro exposure. Extensive washing of these spleen cells could not reverse this binding. Such DNP-Ficoll-exposed and washed F1 male spleen cells could, after transfer, aid normal untreated F1 female cells in their rescue function. The defective F1 male spleen cells could convey immunogenic quantities of DNP-Ficoll to the "rescuing" F1 female cells. Mitomycin treatment of F1 male cells did not interfere with their conveyor function. Goat anti-mouse mu serum impeded the passive antigen conveyor function of defective F1 male cells as did prior exposure to high concentrations of free DNP hapten. Our data support the view that the B cell defect of CBA/N X C3H/HeN F1 male mice does not relate to antigen binding, but rather to an inability to be effectively triggered by certain cell-bound polymeric antigens.

Human Urine-Derived Stem Cells: Potential for Cell-Based Therapy of Cartilage Defects

PubMed Central

Chen, Long; Li, Lang; Xing, Fei; Peng, Jing; Peng, Kun; Wang, Yuanzheng

2018-01-01

Stem cell therapy is considered an optimistic approach to replace current treatments for cartilage defects. Recently, human urine-derived stem cells (hUSCs), which are isolated from the urine, are studied as a promising candidate for many tissue engineering therapies due to their multipotency and sufficient proliferation activities. However, it has not yet been reported whether hUSCs can be employed in cartilage defects. In this study, we revealed that induced hUSCs expressed chondrogenic-related proteins, including aggrecan and collagen II, and their gene expression levels were upregulated in vitro. Moreover, we combined hUSCs with hyaluronic acid (HA) and injected hUSCs-HA into a rabbit knee joint with cartilage defect. Twelve weeks after the injection, the histologic analyses (HE, toluidine blue, and Masson trichrome staining), immunohistochemistry (aggrecan and collagen II), and histologic grade of the sample indicated that hUSCs-HA could stimulate much more neocartilage formation compared with hUSCs alone, pure HA, and saline, which only induced the modest cartilage regeneration. In this study, we demonstrated that hUSCs could be a potential cell source for stem cell therapies to treat cartilage-related defects in the future. PMID:29765413

Topical Olive Leaf Extract Improves Healing of Oral Mucositis in Golden Hamsters.

PubMed

Showraki, Najmeh; Mardani, Maryam; Emamghoreishi, Masoumeh; Andishe-Tadbir, Azadeh; Aram, Alireza; Mehriar, Peiman; Omidi, Mahmoud; Sepehrimanesh, Masood; Koohi-Hosseinabadi, Omid; Tanideh, Nader

2016-12-01

Oral mucositis (OM) is a common side effect of anti-cancer drugs and needs significant attention for its prevention. This study aimed to evaluate the healing effects of olive leaf extract on 5-fluorouracil-induced OM in golden hamster. OM was induced in 63 male golden hamsters by the combination of 5-fluorouracil injections (days 0, 5 and 10) and the abrasion of the cheek pouch (days 3 and 4). On day 12, hamsters were received topical olive leaf extract ointment, base of ointment, or no treatment (control) for 5 days. Histopathology evaluations, blood examinations, and tissue malondialdehyde level measurement were performed 1, 3 and 5 days after treatments. Histopathology score and tissue malondialdehyde level were significantly lower in olive leaf extract treated group in comparison with control and base groups ( p = 0.000). Significant decreases in white blood cell, hemoglobin, hematocrit , and mean corpuscular volume and an increase in mean corpuscular hemoglobin concentration were observed in olive leaf extract treated group in comparison with control and base groups ( p < 0.05). Our findings demonstrated that daily application of olive leaf extract ointment had healing effect on 5-fluorouracil induced OM in hamsters. Moreover, the beneficial effect of olive leaf extract on OM might be due to its antioxidant and anti-inflammatory properties.

A mechanistic study on the effect of dexamethasone in moderating cell death in Chinese Hamster Ovary cell cultures.

PubMed

Jing, Ying; Qian, Yueming; Ghandi, Mahmoud; He, Aiqing; Borys, Michael C; Pan, Shih-Hsie; Li, Zheng Jian

2012-01-01

Dexamethasone (DEX) was previously shown (Jing et al., Biotechnol Bioeng. 2010;107:488-496) to play a dual role in increasing sialylation of recombinant glycoproteins produced by Chinese Hamster Ovary (CHO) cells. DEX addition increased sialic acid levels of a recombinant fusion protein through increased expression of α2,3-sialyltransferase and β1,4-galactosyltransferase, but also decreased the sialidase-mediated, extracellular degradation of sialic acid through slowing cell death at the end of the culture period. This study examines the underlying mechanism for this cytoprotective action by studying the transcriptional response of the CHO cell genome upon DEX treatment using DNA microarrays and gene ontology term analysis. Many of those genes showing a significant transcriptional response were associated with the regulation of programmed cell death. The gene with the highest change in expression level, as validated by Quantitative PCR assays with TaqMan® probes and confirmed by Western Blot analysis, was the antiapoptotic gene Tsc22d3, also referred to as GILZ (glucocorticoid-induced leucine zipper). The pathway by which DEX suppressed cell death towards the end of the culture period was also confirmed by showing involvement of glucocorticoid receptors and GILZ through studies using the glucocorticoid antagonist mifepristone (RU-486). These findings advance the understanding of the mechanism by which DEX suppresses cell death in CHO cells and provide a rationale for the application of glucocorticoids in CHO cell culture processes. Copyright © 2011 American Institute of Chemical Engineers (AIChE).

neu mutation in schwannomas induced transplacentally in Syrian golden hamsters by N-nitrosoethylurea: high incidence but low allelic representation.

PubMed

Buzard, G S; Enomoto, T; Hongyo, T; Perantoni, A O; Diwan, B A; Devor, D E; Reed, C D; Dove, L F; Rice, J M

1999-10-01

Peripheral nerve tumors (PNT) and melanomas induced transplacentally on day 14 of gestation in Syrian golden hamsters by N-nitrosoethylurea were analyzed for activated oncogenes by the NIH 3T3 transfection assay, and for mutations in the neu oncogene by direct sequencing, allele-specific oligonucleotide hybridization, MnlI restriction-fragment-length polymorphism, single-strand conformation polymorphism, and mismatch amplification mutation assays. All (67/67) of the PNT, but none of the melanomas, contained a somatic missense T --> A transversion within the neu oncogene transmembrane domain at a site corresponding to that which also occurs in rat schwannomas transplacentally induced by N-nitrosoethylurea. In only 2 of the 67 individual hamster PNT did the majority of tumor cells appear to carry the mutant neu allele, in contrast to comparable rat schwannomas in which it overwhelmingly predominates. The low fraction of hamster tumor cells carrying the mutation was stable through multiple transplantation passages. In the hamster, as in the rat, specific point-mutational activation of the neu oncogene thus constitutes the major pathway for induction of PNT by transplacental exposure to an alkylating agent, but the low allelic representation of mutant neu in hamster PNT suggests a significant difference in mechanism by which the mutant oncogene acts in this species.

Functional integrins from normal and glycosylation-deficient baby hamster kidney cells. Terminal processing of asparagine-linked oligosaccharides is not correlated with fibronectin-binding activity.

PubMed

Koyama, T; Hughes, R C

1992-12-25

We have examined the properties of the alpha 5 beta 1 integrin of baby hamster kidney (BHK) cells, a ricin-resistant variant Ric14 lacking N-acetylglucosaminyl transferase I, and hence unable to complete assembly of hybrid- or complex-type N-glycans, and BHK cells treated with 1-deoxymannojirimycin (dMM), an inhibitor of Golgi mannosidases involved in the initial processing of N-glycan precursors. Comparable amounts of alpha 5 beta 1 integrin were isolated from these cells by chromatography of detergent extracts on a fibronectin cell-binding fragment affinity column and elution with EDTA. The alpha 5 beta 1 integrin obtained from normal BHK cells by fibronectin affinity chromatography contained mainly endoglycosidase H-resistant oligosaccharides, whereas in RicR14 cells or dMM-treated BHK cells these were entirely endoglycosidase H-sensitive. Analysis of lactoperoxidase labeled or long term biosynthetically 35S-labeled proteins from cultures of normal or glycosylation deficient cells showed similar steady state levels of alpha 5 beta 1 integrin and expression at the cell surface. Pulse-chase experiments in normal BHK cells showed rapid conversion of the alpha 5 subunit into a mature form containing oligosaccharides resistant to endoglycosidase H and slower maturation of a precursor beta 1 subunit, as in other cell types. In Ric14 cells the precursor beta 1 subunit was found to carry glycans larger than the fully processed Man5GlcNAc2 glycan of the mature subunit, indicating that the bulk precursor pool had not been translocated into the cis-Golgi compartment containing mannosidase I. We conclude that in BHK cells terminal oligosaccharide processing of alpha 5 beta 1 integrin subunits is not required for dimer formation, surface expression, and fibronectin binding, and that expression of the glycosylation defect of Ric14 cells on the alpha 5 beta 1 integrin does not account for the reduced adhesiveness of these cells on fibronectin compared with normal and d

Induction of carcinomas and sarcomas by 9,10-dimethyl-1,2-benzanthracene administration into the hamster maxillary sinus.

PubMed

Yura, Y; Tsujimoto, H; Kusaka, J; Harada, K; Yoshida, H; Sato, M

1995-03-01

To determine whether the local administration of 9,10-dimethyl-1,2-benzanthracene (DMBA) into the hamster maxillary sinus induced carcinoma at the injected site, hamsters were injected with 30 microliters of 0.5% solution of DMBA in dimethyl sulfoxide (DMSO) through the infraorbital foramen into the maxillary sinus once weekly for 10 weeks (Group 2). Another group of hamsters (Group 1) received similar injections of 30 microliters of DMSO only. In a third group of animals (Group 3), a roll of oxycellulose was inserted into the maxillary sinus and 40 microliters of a 2% solution of DMBA in DMSO was injected once. Sinonasal carcinomas were demonstrated in 73% (8/11) of the hamsters in Group 2 and sarcomas were shown in 73% (8/11) of the hamsters in Group 3, as well as some carcinomas. No tumors were seen in the Group 1 hamsters. Histologic examination revealed squamous cell carcinomas arising from the surface epithelium and submucous glands of the nasal cavity and maxillary sinus. These findings indicate that the intrasinal administration of a 0.5% solution of DMBA in DMSO is a reliable method for inducing maxillary sinus cancer.

Chemoprevention by Quercetin of Oral Squamous Cell Carcinoma by Suppression of the NF-κB Signaling Pathway in DMBA-treated Hamsters.

PubMed

Zhang, Wen; Yin, Gang; Dai, Jianguo; Sun, Y U; Hoffman, Robert M; Yang, Zhijian; Fan, Yuan

2017-08-01

The aim of this study was to investigate the effects of the flavonoid quercetin on chemoprevention of oral squamous cell carcinoma (OSCC). The study involved molecular signaling pathways in 7,12-dimethylbenz(a) anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis. DMBA (0.5%) was painted at the right buccal pouches of hamsters for 14 weeks to induce carcinoma. DMBA-treated hamsters received simultaneous doses of quercetin. Animals without DMBA induction were used as normal controls. The incidence of OSCC and the severity of pre-malignant lesions were determined histologically. Apoptosis in the pouch tissue was determined by TUNEL staining. The mRNA and protein expression of NF-κB p50 and p65, as well as Bcl-2 and Bax genes were analyzed using RT-PCR and Western blotting, respectively. Quercetin, at various doses, significantly reduced OSCC incidence and severity of hyperplasia and dysplasia compared to the DMBA-induction-only group (p<0.01). Apoptosis was induced by quercetin treatment compared to the DMBA-induction-only group (p<0.01). mRNA and protein expression of NF-κB p50, p65 as well as Bcl-2 genes were significantly suppressed by quercetin at high doses compared to DMBA induction only (p<0.05). However, mRNA and protein expression of the Bax gene was increased by quercetin treatment at medium and high doses, compared to the DMBA-induction-only group (p<0.05). Quercetin significantly reduced body-weight loss compared to the DMBA-induction-only group (p<0.05). Quercetin reduced tumor incidence and induced apoptosis through modulation of NF-κB signaling and its target genes Bcl-2 and Bax in the DMBA-induced carcigenesis hamster model, suggesting the potential of quercetin as a candidate for OSCC chemoprevention. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Mitochondrial function in diaphragm of emphysematous hamsters after treatment with nandrolone.

PubMed

Wijnhoven, Hanneke J H; Ennen, Leo; Rodenburg, Richard J T; Dekhuijzen, P N Richard

2006-01-01

Respiratory failure in patients with COPD may be caused by insufficient force production or insufficient endurance capacity of the respiratory muscles. Anabolic steroids may improve respiratory muscle function in COPD. The effect of anabolic steroids on mitochondrial function in the diaphragm in emphysema is unknown. In an emphysematous male hamster model, we investigated whether administration of the anabolic steroid nandrolone decanoate (ND) altered the activity of mitochondrial respiratory chain complexes in the diaphragm. The bodyweight of hamsters treated with ND was decreased after treatment compared with initial values, and serum testosterone levels were significantly lower in hamsters treated with ND than in control hamsters. No difference in the activity of mitochondrial respiratory chain complexes in the diaphragm between normal and emphysematous hamsters was observed. Treatment with ND did not change the activity of mitochondrial respiratory chain complexes in the diaphragm of both normal and emphysematous hamsters. In emphysematous hamsters, administration of ND decreased the activity of succinate:cytochrome c oxidoreductase compared with ND treatment in normal hamsters. We conclude that anabolic steroids have negative effects on the activity of succinate:cytochrome c oxidoreductase and anabolic status in this emphysematous hamster model.

Mitochondrial function in diaphragm of emphysematous hamsters after treatment with nandrolone

PubMed Central

Wijnhoven, Hanneke JH; Ennen, Leo; Rodenburg, Richard JT; Dekhuijzen, PN Richard

2006-01-01

Respiratory failure in patients with COPD may be caused by insufficient force production or insufficient endurance capacity of the respiratory muscles. Anabolic steroids may improve respiratory muscle function in COPD. The effect of anabolic steroids on mitochondrial function in the diaphragm in emphysema is unknown. In an emphysematous male hamster model, we investigated whether administration of the anabolic steroid nandrolone decanoate (ND) altered the activity of mitochondrial respiratory chain complexes in the diaphragm. The bodyweight of hamsters treated with ND was decreased after treatment compared with initial values, and serum testosterone levels were significantly lower in hamsters treated with ND than in control hamsters. No difference in the activity of mitochondrial respiratory chain complexes in the diaphragm between normal and emphysematous hamsters was observed. Treatment with ND did not change the activity of mitochondrial respiratory chain complexes in the diaphragm of both normal and emphysematous hamsters. In emphysematous hamsters, administration of ND decreased the activity of succinate:cytochrome c oxidoreductase compared with ND treatment in normal hamsters. We conclude that anabolic steroids have negative effects on the activity of succinate:cytochrome c oxidoreductase and anabolic status in this emphysematous hamster model. PMID:18046906

Transmission and adaptation of chronic wasting disease to hamsters and transgenic mice: evidence for strains.

PubMed

Raymond, Gregory J; Raymond, Lynne D; Meade-White, Kimberly D; Hughson, Andrew G; Favara, Cynthia; Gardner, Donald; Williams, Elizabeth S; Miller, Michael W; Race, Richard E; Caughey, Byron

2007-04-01

In vitro screening using the cell-free prion protein conversion system indicated that certain rodents may be susceptible to chronic wasting disease (CWD). Therefore, CWD isolates from mule deer, white-tailed deer, and elk were inoculated intracerebrally into various rodent species to assess the rodents' susceptibility and to develop new rodent models of CWD. The species inoculated were Syrian golden, Djungarian, Chinese, Siberian, and Armenian hamsters, transgenic mice expressing the Syrian golden hamster prion protein, and RML Swiss and C57BL10 wild-type mice. The transgenic mice and the Syrian golden, Chinese, Siberian, and Armenian hamsters had limited susceptibility to certain of the CWD inocula, as evidenced by incomplete attack rates and long incubation periods. For serial passages of CWD isolates in Syrian golden hamsters, incubation periods rapidly stabilized, with isolates having either short (85 to 89 days) or long (408 to 544 days) mean incubation periods and distinct neuropathological patterns. In contrast, wild-type mouse strains and Djungarian hamsters were not susceptible to CWD. These results show that CWD can be transmitted and adapted to some species of rodents and suggest that the cervid-derived CWD inocula may have contained or diverged into at least two distinct transmissible spongiform encephalopathy strains.

Caffeine induces metformin anticancer effect on fibrosarcoma in hamsters.

PubMed

Popović, D J; Lalošević, D; Miljković, D; Popović, K J; Čapo, I; Popović, J K

2018-04-01

We investigated the effect of metformin and caffeine on fibrosarcoma in hamsters. 32 Syrian golden hamsters of both sexes, weighing approximately 100 g, were randomly allocated to 3 experimental and 2 control groups, with a minimum of 6 animals per group. 2 x 106 BHK-21/C13 cells in 1 ml were injected subcutaneously into the animals' back in 4 groups. The first experimental group started peroral treatment with metformin 500 mg/kg daily, the second with caffeine 100 mg/kg daily and the third with a combination of metformin 500 mg/kg and caffeine 100 mg/kg daily, via a gastric probe 3 days before tumor inoculation. After 2 weeks, when the tumors were approximately 2 cm in the control group, all animals were sacrificed. The blood was collected for glucose and other analyses. The tumors were excised and weighed and their diameters were measured. The tumor samples were pathohistologically (HE) and immunohistochemically (Ki-67, CD 31, COX IV, GLUT-1, iNOS) assessed and the main organs toxicologically analyzed, including the control animals that had received metformin and caffeine. Tumor volume was determined using the formula LxS2/2, where L was the longest and S the shortest diameter. Ki-67-positive cells in the tumor samples were quantified. Images were taken and processed by software UTHSCSA Image Tools for Windows Version 3.00. Statistical significances were determined by the Student's t-test. The combination of metformin and caffeine inhibited fibrosarcoma growth in hamsters without toxicity. Administration of metformin with caffeine might be an effective and safe approach in novel nontoxic adjuvant anticancer treatment.

Long-term carcinogenicity study in Syrian golden hamster of particulate emissions from coal- and oil-fired power plants

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

Persson, S.A.; Ahlberg, M.; Berghem, L.

1988-04-01

Male Syrian golden hamsters were given 15 weekly intratracheal instillations with suspensions of coal fly ash or oil fly ash. Controls were instilled with saline containing gelatine (0.5 g/100 mL) or to check particle effects with suspensions of hematite (Fe/sub 2/O/sub 3/). The common weekly dose was 4.5 mg/hamster. In addition, one subgroup of hamsters was treated with oil fly ash at a weekly dose of 3.0 mg/hamster and another with coal fly ash at a weekly dose of 6.0 mg/hamster. Other groups of hamsters were treated with suspensions of benzo(a)pyrene (BaP) or with suspensions on coal fly ash, oilmore » fly ash, or Fe/sub 2/O/sub 3/ coated with BaP. The mass median aerodynamic diameters of the coal and oil fly ashes were 4.4 microns and 28 microns, respectively. Hamsters treated with oil fly ash showed a higher frequency of bronchiolar-alveolar hyperplasia than hamsters in the other treatment groups. Squamous dysplasia and squamous metaplasia were most frequent in animals treated with suspensions of BaP or BaP-coated particles. The earliest appearance of a tumor, the highest incidence of tumors, and the highest incidence of malignant tumors were observed in hamsters treated with oil fly ash coated with BaP. Squamous cell carcinoma and adenosquamous carcinoma were the most frequent malignant tumors. No malignant tumors and only few benign tumors were observed in hamsters instilled with suspensions of fly ash not coated with BaP. The present study gives no indication that coal fly ash could create more serious health problems than oil fly ash.« less

MEK-ERK inhibition corrects the defect in VLDL assembly in HepG2 cells: potential role of ERK in VLDL-ApoB100 particle assembly.

PubMed

Tsai, Julie; Qiu, Wei; Kohen-Avramoglu, Rita; Adeli, Khosrow

2007-01-01

Hepatic VLDL assembly is defective in HepG2 cells, resulting in the secretion of immature triglyceride-poor LDL-sized apoB particles. We investigated the mechanisms underlying defective VLDL assembly in HepG2 and have obtained evidence implicating the MEK-ERK pathway. HepG2 cells exhibited considerably higher levels of the ERK1/2 mass and activity compared with primary hepatocytes. Inhibition of ERK1/2 using the MEK1/MEK2 inhibitor, U0126 (but not the inactive analogue) led to a significant increase in apoB secretion. In the presence of oleic acid, ERK1/2 inhibition caused a major shift in the lipoprotein distribution with a majority of particles secreted as VLDL, an effect independent of insulin. In contrast, overexpression of constitutively active MEK1 decreased apoB and large VLDL secretion. MEK1/2 inhibition significantly increased both cellular and microsomal TG mass, and mRNA levels for DGAT-1 and DGAT-2. In contrast to ERK, modulation of the PI3-K pathway or inhibition of the p38 MAP kinase, had no effect on lipoprotein density profile. Modulation of the MEK-ERK pathway in primary hamster hepatocytes led to changes in apoB secretion and altered the density profile of apoB-containing lipoproteins. Inhibition of the overactive ras-MEK-ERK pathway in HepG2 cells can correct the defect in VLDL assembly leading to the secretion of large, VLDL-sized particles, similar to primary hepatocytes, implicating the MEK-ERK cascade in VLDL assembly in the HepG2 model. Modulation of this pathway in primary hepatocytes also regulates apoB secretion and appears to alter the formation of VLDL-1 sized particles.

Heat and cold acclimation in helium-cold hypothermia in the hamster.

NASA Technical Reports Server (NTRS)

Musacchia, X. J.

1972-01-01

A study was made of the effects of acclimation of hamsters to high (34-35 C) and low (4-5 C) temperatures for periods up to 6 weeks on the induction of hypothermia in hamsters. Hypothermia was achieved by exposing hamsters to a helox mixture of 80% helium and 20% oxygen at 0 C. Hypothermic induction was most rapid (2-3 hr) in heat-acclimated hamsters and slowest (6-12 hr) in cold-acclimated hamsters. The induction period was intermediate (5-8 hr) in room temperature nonacclimated animals (controls). Survival time in hypothermia was relatable to previous temperature acclimations. The hypothesis that thermogenesis in cold-acclimated hamsters would accentuate resistance to induction of hypothermia was substantiated.

Understanding Transcriptional Enhancement in Monoclonal Antibody-Producing Chinese Hamster Ovary Cells

NASA Astrophysics Data System (ADS)

Nicoletti, Sarah E.

With the demand for monoclonal antibody (mAB) therapeutics continually increasing, the need to better understand what makes a high productivity clone has gained substantial interest. Monoclonal antibody producing Chinese hamster ovary (CHO) cells with different productivities were provided by a biopharmaceutical company for investigation. Gene copy numbers, mRNA levels, and mAb productivities were previously determined for two low producing clones and their amplified progeny. These results showed an increase in mRNA copy number in amplified clones, which correlated to the observed increases in specific productivity of these clones. The presence of multiple copies of mRNA per one copy of DNA in the higher productivity clones has been coined as transcriptional enhancement. The methylation status of the CMV promoter as well as transcription factor/promoter interactions were evaluated to determine the cause of transcriptional enhancement. Methylation analysis via bisulfite sequencing revealed no significant difference in overall methylation status of the CMV promoter. These data did, however, reveal the possibility of differential interactions of transcription factors between the high and low productivity cell clones. This finding was further supported by chromatin immunoprecipitations previously performed in the lab, as well as literature studies. Transcription activator-like effector (TALE) binding proteins were constructed and utilized to selectively immunoprecipitate the CMV promoter along with its associated transcription factors in the different CHO cell clones. Cells were transfected with the TALE proteins, harvested and subjected to a ChIP-like procedure. Results obtained from the TALE ChIP demonstrated the lack of binding of the protein to the promoter and the need to redesign the TALE. Overall, results obtained from this study were unable to give a clear indication as to the causes of transcriptional enhancement in the amplified CHO cell clones. Further

Induction of lyme arthritis in LSH hamsters

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

Schmitz, J.L.; Schell, R.F.; Hejka, A.

1988-09-01

In studies of experimental Lyme disease, a major obstacle has been the unavailability of a suitable animal model. We found that irradiated LSH/Ss Lak hamsters developed arthritis after injection of Borrelia burgdorferi in the hind paws. When nonirradiated hamsters were injected in the hind paws with B. burgdorferi, acute transient synovitis was present. A diffuse neutrophilic infiltrate involved the synovia and periarticular structures. The inflammation was associated with edema, hyperemia, and granulation tissue. Numerous spirochetes were seen in the synovial and subsynovial tissues. The histopathologic changes were enhanced in irradiated hamsters. The onset and duration of the induced swelling weremore » dependent on the dose of radiation and the inoculum of spirochetes. Inoculation of irradiated hamsters with Formalin-killed spirochetes or medium in which B. burgdorferi had grown for 7 days failed to induce swelling. This animal model should prove useful for studies of the immune response to B. burgdorferi and the pathogenesis of Lyme arthritis.« less

Relative biological effectiveness of accelerated heavy ions for induction of morphological transformation in Syrian hamster embryo cells.

PubMed

Han, Z B; Suzuki, H; Suzuki, F; Suzuki, M; Furusawa, Y; Kato, T; Ikenaga, M

1998-09-01

Syrian hamster embryo cells were used to study the morphological transformation induced by accelerated heavy ions with different linear energy transfer (LET) ranging from 13 to 400 keV/micron. Exponentially growing cells were irradiated with 12C or 28Si ion beams generated by the Heavy Ion Medical Accelerator in Chiba (HIMAC), then inoculated to culture dishes. Morphologically altered colonies were scored as transformants. Over the LET range examined, the frequency of transformation induced by the heavy ions increased sharply at very low doses no greater than 5 cGy. The relative biological effectiveness (RBE) of the heavy ions relative to X-rays first increased with LET, reached a maximum value of about 7 at 100 keV/micron, then decreased with the further increase of LET. Our findings confirmed that high LET heavy ions are much more effective than X-rays for the induction of in vitro cell transformation.

Effects of porcine pancreatic enzymes on the pancreas of hamsters. Part 2: carcinogenesis studies.

PubMed

Nozawa, Fumiaki; Yalniz, Mehmet; Saruc, Murat; Standop, Jens; Egami, Hiroshi; Pour, Parviz M

2012-09-10

Our previous study suggested that porcine pancreatic extract in hamsters with peripheral insulin resistance, normalizes insulin output, islet size and pancreatic DNA synthetic rate. It also inhibited the growth of human pancreatic cancer cells in nude mice. To examine the potential value of the porcine pancreatic extract in controlling pancreatic carcinogenesis in this model, the present experiment was performed. Hamsters were fed a high fat diet and four weeks later when insulin resistance emerges, they were divided into two groups. One group received 1 g/kg BW of porcine pancreatic extract in drinking water and the other group received tap water. One week later, when insulin output normalizes in porcine pancreatic extract-treated hamsters, a single subcutaneous injection of N-nitrosobis-(2-oxopropyl) amine (BOP) at a dose of 40 mg/kg BW was given to all hamsters. The experiment was terminated at 43 weeks after the porcine pancreatic extract treatment. The number and size of pancreatic tumors, blood glucose, insulin, amylase and lipase levels, the average size of islets and the number of insulin cells/islets were determined. The incidence of pancreatic cancer was significantly lower in the porcine pancreatic extract group (P=0.043), as well as the plasma insulin level and the size of the islets in the porcine pancreatic extract group were significantly lower (P<0.001) than in the control group. No significantly differences were found in the glucose level between the groups. These results show that porcine pancreatic extract has a potential to inhibit pancreatic cancer growth.

Directed Student Inquiry: Modeling in Roborovsky Hamsters

ERIC Educational Resources Information Center

Elwess, Nancy L.; Bouchard, Adam

2007-01-01

In this inquiry-based activity, Roborovsky hamsters are used to provide students with an opportunity to develop their skills of analysis, inquiry, and design. These hamsters are easy to maintain, yet offer students a means to use conventional techniques and those of their own design to make further observations through measuring, assessing, and…

Pineal melatonin synthesis in Syrian hamsters: A summary

NASA Astrophysics Data System (ADS)

Rollag, M. D.

1982-12-01

During the past decade there has been ample documentation of the proposition that the pineal gland mediates photoperiodic influences upon reproductive behavior of hamsters. It is commonly hypothesized that the pineal gland expresses its activity by transformation of photoperiodic information into an hormonal output, that hormone being melatonin. If this hypothesis is correct, there must be some essential diffrence in melatonin's output when hamsters are exposed to different photoperiodic environments. The experiments summarized in this communication analyze pineal melatonin contents in Syrian hamsters maintained in a variety of photoperiodic conditions during different physiological states. The results demonstrate that adult hamsters have a daily surge in pineal melatonin content throughout their lifetime when exposed to simulated annual photoperiodic cycles. There is some fluctuation in the amount of pineal melatonin produced during different physiological states and photoperiodic environments, but these fluctuations seem small when compared to those normally found for other regulatory hormones. When hamsters are exposed to different photoperiodic regimens, the daily melatonin surge maintains a relatively constant phase relationship with respect to the onset of daily activity. There is a concomitant change in its phase relationship with respect to light-dark transitions.

Cell performance and defect behavior in proton-irradiated lithium-counterdoped n(+)p silicon solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Stupica, J. W.; Swartz, C. K.; Goradia, C.

1986-01-01

Lithium-counterdoped n(+)p silicon solar cells were irradiated by 10-MeV protons, and their performance was determined as a function of fluence. It was found that the cell with the highest lithium concentration exhibited the higher radiation resistance. Deep-level transient spectroscopy studies of deep-level defects were used to identify two lithium-related defects. Defect energy levels obtained after the present 10-MeV irradiations were found to be markedly different than those observed after previous 1-MeV electron irradiations. However, the present DLTS data are consistent with previous suggestion by Weinberg et al. (1984) of a lithium-oxygen interaction which tends to inhibit formation of an interstitial boron-oxygen defect.

Fasting-induced daily torpor in desert hamsters (Phodopus roborovskii).

PubMed

Chi, Qing-Sheng; Wan, Xin-Rong; Geiser, Fritz; Wang, De-Hua

2016-09-01

Daily torpor is frequently expressed in small rodents when facing energetically unfavorable ambient conditions. Desert hamsters (Phodopus roborovskii, ~20g) appear to be an exception as they have been described as homeothermic. However, we hypothesized that they can use torpor because we observed reversible decreases of body temperature (Tb) in fasted hamsters. To test this hypothesis we (i) randomly exposed fasted summer-acclimated hamsters to ambient temperatures (Tas) ranging from 5 to 30°C or (ii) supplied them with different rations of food at Ta 23°C. All desert hamsters showed heterothermy with the lowest mean Tb of 31.4±1.9°C (minimum, 29.0°C) and 31.8±2.0°C (minimum, 29.0°C) when fasted at Ta of 23°C and 19°C, respectively. Below Ta 19°C, the lowest Tb and metabolic rate increased and the proportion of hamsters using heterothermy declined. At Ta 5°C, nearly all hamsters remained normothermic by increasing heat production, suggesting that the heterothermy only occurs in moderately cold conditions, perhaps to avoid freezing at extremely low Tas. During heterothermy, Tbs below 31°C with metabolic rates below 25% of those during normothermia were detected in four individuals at Ta of 19°C and 23°C. Consequently, by definition, our observations confirm that fasted desert hamsters are capable of shallow daily torpor. The negative correlation between the lowest Tbs and amount of food supply shows that heterothermy was mainly triggered by food shortage. Our data indicate that summer-acclimated desert hamsters can express fasting-induced shallow daily torpor, which may be of significance for energy conservation and survival in the wild. Copyright © 2016 Elsevier Inc. All rights reserved.

Inhaled ozone as a mutagen. II - Effect on the frequency of chromosome aberrations observed in irradiated Chinese hamsters.

NASA Technical Reports Server (NTRS)

Zelac, R. E.; Cromroy, H. L.; Bolch, W. E., Jr.; Dunavant, B. G.; Bevis, H. A.

1971-01-01

Exposure-adjusted break frequencies for chromosome aberrations produced in Chinese hamster circulating blood lymphocytes were the quantitative indicator of damage from 5 hrs of exposure to X-radiation and/or to ozone. Radiation produced 5.51 x 0.0001 breaks/cell rad for cells withdrawn 2 weeks after exposure, a reasonable value when compared with data from in vivo exposure of human lymphocytes and Chinese hamster bone marrow cells. Animals exposed to the two agents simultaneously exhibited more than 70% of the total breaks anticipated assuming the expected equal contributions to be additive. Extending to humans, at presently permitted levels, exposure to ozone would be much more detrimental than exposure to radiati*n.

Pleural dosimetry and pathobiological responses in rats and hamsters exposed subchronically to MMVF 10a fiberglass.

PubMed

Bermudez, Edilberto; Mangum, James B; Moss, Owen R; Wong, Brian A; Everitt, Jeffrey I

2003-07-01

Interspecies differences in pulmonary and pleural responses to the inhalation of natural mineral and synthetic vitreous fibers have been observed in chronic and subchronic studies. However, the reasons for these differences are not clearly understood. There are also fiber-specific differences in the outcome of chronic inhalation exposure to natural mineral and synthetic vitreous fibers. Whether these differences are dependent upon the ability of these fibers to translocate to the pleural space is unknown. The present study was conducted to compare retained fiber burdens and selected pathological responses in the pleural compartments of rats and hamsters following subchronic inhalation of MMVF 10a fiberglass, a fiber negative for tumorigenesis or fibrosis in chronic studies. Fischer 344 rats and Syrian golden hamsters were exposed for 4 or 12 weeks by nose-only inhalation at nominal aerosol mass concentrations of 45 mg/m3 (610 WHO fibers/cc). Pulmonary fiber burdens and pulmonary inflammatory responses were greater in rats than in hamsters. The total number of fibers in the lung was approximately three orders of magnitude greater than in the pleural compartment. Pleural burdens in the hamster (160 fibers/cm2 surface area) were significantly greater than burdens in similarly exposed rats (60 fibers/cm2 surface area) following 12 weeks of exposure. With time postexposure, pleural burdens decreased in hamsters but were essentially unchanged in rats. Pleural inflammatory responses in both species were minimal. In rats, pleural inflammation was characterized by increased numbers of macrophages and increases in mesothelial cell replication during the period of fiber exposure. In contrast, hamsters had increased numbers of macrophages and lymphocytes, and mesothelial-cell replication indices were elevated on the parietal pleura of the costal wall and diaphragm, with some of these responses persisting through 12 weeks of postexposure recovery. Taken together, the results

The fluidity of Chinese hamster ovary cell and bull sperm membranes after cholesterol addition.

PubMed

Purdy, P H; Fox, M H; Graham, J K

2005-08-01

Cell plasma membrane fluidity is affected by membrane lipid and protein composition as well as temperature. Altering the cholesterol content of a membrane can change membrane fluidity at different temperatures and this may affect cell survival during cryopreservation. In these experiments, we examined the effect that adding cholesterol to the membranes of Chinese hamster ovary cells (CHO) and bull sperm had on cell plasma membrane fluidity and cell survival when cells were cooled to 5 degrees C or were cryopreserved. Cells were treated with 0, 1.5 or 5.0mg cholesterol-loaded cyclodextrin (CLC), stained with N-((4-(6-phenyl-1,3,5-hexatrienyl)phenyl)propyl)trimethylammonium-p-toluenesulfonate (TMAP-DPH) to evaluate membrane fluidity and with propidium iodide to evaluate cell viability, prior to analysis by flow cytometry at 23, 5 degrees C, and after cryopreservation. CHO cells exhibited a single cell population with all cells having similar membrane fluidity. Membrane fluidity did not change when temperature had been reduced and then returned to 23 degrees C (P<0.05), however, adding cholesterol to the cells induced membranes to become more rigid (P<0.05). Bull sperm samples consisted of two cell subpopulations, one having relatively higher membrane fluidity than the other, regardless of cholesterol treatment or temperature. In addition, cells possessing the highest membrane fluidity did not survive cooling or cryopreservation efficiently. CLC treatment did not significantly alter membrane fluidity after temperature changes, but did maintain higher percentages of spermatozoa surviving cooling to 5 degrees C and cryopreservation (P<0.05). In conclusion, adding cholesterol to cell resulted in detectable membrane fluidity changes in CHO cells and increased survival of bull sperm after cooling to 5 degrees C and after cryopreservation.

Characteristics of 263K Scrapie Agent in Multiple Hamster Species

PubMed Central

Barbian, Kent D.; Race, Brent; Favara, Cynthia; Gardner, Don; Taubner, Lara; Porcella, Stephen; Race, Richard

2009-01-01

Transmissible spongiform encephalopathy (TSE) diseases are known to cross species barriers, but the pathologic and biochemical changes that occur during transmission are not well understood. To better understand these changes, we infected 6 hamster species with 263K hamster scrapie strain and, after each of 3 successive passages in the new species, analyzed abnormal proteinase K (PK)–resistant prion protein (PrPres) glycoform ratios, PrPres PK sensitivity, incubation periods, and lesion profiles. Unique 263K molecular and biochemical profiles evolved in each of the infected hamster species. Characteristics of 263K in the new hamster species seemed to correlate best with host factors rather than agent strain. Furthermore, 2 polymorphic regions of the prion protein amino acid sequence correlated with profile differences in these TSE-infected hamster species. PMID:19193264

CHO-cell mutant with a defect in cytokinesis

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

Thompson, L.H.; Lindl, P.A.

1976-01-01

In a selection procedure designed to enrich for temperature-sensitive mutant cells blocked in mitosis a CHO-cell mutant was isolated which has a defect in cytokinesis as the basis of its temperature-sensitive phenotype. Cultures of the mutant had an abnormally high percentage (ie, 34 percent) of polyploid cells at the permissive temperature of 34/sup 0/C and showed further increased frequencies of polyploidy as well as many multinucleated cells at 38.5/sup 0/ and 39.5/sup 0/. When the mutant cells were synchronized in metaphase by Colcemid arrest and then placed into fresh medium at nonpermissive temperature, they did not divide although the completionmore » of mitosis appeared cytologically normal. Ultrastructural examination by electron microscopy of such synchronized cells at telophase revealed no specific defects in cellular components other than failure of development of a normal midbody. The sensitivity of the mutant to cytochalasin B and to Colcemid was the same as for wild-type cells. This mutation behaved as recessive in tetraploid cell hybrids constructed by fusing the mutant with a CHO strain which was wild-type with respect to temperature sensitivity.« less

Suppress carrier recombination by introducing defects. The case of Si solar cell

DOE PAGES

Liu, Yuanyue; Stradins, Paul; Deng, Huixiong; ...

2016-01-11

Deep level defects are usually harmful to solar cells. Here we show that incorporation of selected deep level defects in the carrier-collecting region, however, can be utilized to improve the efficiency of optoelectronic devices. The designed defects can help the transport of the majority carriers by creating defect levels that is resonant with the band edge state, and/or reduce the concentration of minority carriers through Coulomb repulsion, thus suppressing the recombination at the carrier-collecting region. The selection process is demonstrated by using Si solar cell as an example. In conclusion, our work enriches the understanding and utilization of the semiconductormore » defects.« less

Effects of porcine pancreatic enzymes on the pancreas of hamsters. Part 1: basic studies.

PubMed

Saruc, Murat; Nozawa, Fumiaki; Yalniz, Mehmet; Itami, Atsushi; Pour, Parviz M

2012-09-10

Porcine pancreatic enzymes (PPE) extracted from glandular stomach has been used for the treatment of pancreatic cancer patients. Unfortunately, no information is available on the in vitro and in vivo effect on the pancreas and other tissues. We used Syrian Golden hamsters, a unique pancreatic cancer model, to obtain basic information on PPE for its eventual use for the treatment of pancreatic cancer. PPE was used in different concentrations in vitro and in vivo. The stability of the enzyme in the water solution was investigated. It was given to the hamsters by gavage in concentrations of 1g/kg and 400 mg/kg for short periods and in aqueous solution for 65 days. Plasma enzyme and insulin, the size of islets and the number of the insulin cells per islet were examined. The enzyme activity of PPE was maintained in water solution for at least 24 hours. Due to its content of calcium chloride it showed a high toxicity to normal and malignant hamster pancreatic cancer cells and human pancreatic cancer cell lines in vitro. PPE did not alter the plasma pancreatic enzyme levels regardless of the dose, duration and application route. On the contrary, PPE reduced their levels significantly. Remarkably, it also reduced the level of insulin, the size of the islets and the number of insulin cells in the islets significantly. The results imply that PPE does not enter the blood circulation but it appears to slow down the function of both the exocrine and endocrine pancreas.

A Systematic Approach to Time-series Metabolite Profiling and RNA-seq Analysis of Chinese Hamster Ovary Cell Culture.

PubMed

Hsu, Han-Hsiu; Araki, Michihiro; Mochizuki, Masao; Hori, Yoshimi; Murata, Masahiro; Kahar, Prihardi; Yoshida, Takanobu; Hasunuma, Tomohisa; Kondo, Akihiko

2017-03-02

Chinese hamster ovary (CHO) cells are the primary host used for biopharmaceutical protein production. The engineering of CHO cells to produce higher amounts of biopharmaceuticals has been highly dependent on empirical approaches, but recent high-throughput "omics" methods are changing the situation in a rational manner. Omics data analyses using gene expression or metabolite profiling make it possible to identify key genes and metabolites in antibody production. Systematic omics approaches using different types of time-series data are expected to further enhance understanding of cellular behaviours and molecular networks for rational design of CHO cells. This study developed a systematic method for obtaining and analysing time-dependent intracellular and extracellular metabolite profiles, RNA-seq data (enzymatic mRNA levels) and cell counts from CHO cell cultures to capture an overall view of the CHO central metabolic pathway (CMP). We then calculated correlation coefficients among all the profiles and visualised the whole CMP by heatmap analysis and metabolic pathway mapping, to classify genes and metabolites together. This approach provides an efficient platform to identify key genes and metabolites in CHO cell culture.

Sindbis virus glycoproteins are abnormally glycosylated in Chinese hamster ovary cells deprived of glucose.

PubMed

Davidson, S K; Hunt, L A

1985-07-01

We have previously demonstrated that Sindbis virus infection of Chinese hamster ovary (CHO) cells altered the protein glycosylation machinery of the cell, so that both normal, full-size (nine mannose-containing) oligosaccharides and abnormal, "truncated' (five mannose-containing) oligosaccharides are transferred from lipid-linked precursors to newly synthesized viral membrane glycoproteins. In the present studies, we have examined the precursor oligosaccharides on viral glycoproteins that were pulse-labelled with [3H]mannose in the presence or absence of glucose, since glucose starvation of uninfected CHO cells has been reported to induce synthesis of truncated precursor oligosaccharides. Pulse-labelling in the absence of glucose led to a greater than 10-fold increase in the relative amount of the truncated precursor oligosaccharides being transferred to the newly synthesized viral glycoproteins and to an apparent underglycosylation of some precursor viral polypeptides, with some asparaginyl sites not acquiring covalently linked oligosaccharides. The mature virion glycoproteins from CHO cells which were pulse-labelled in the absence of glucose and then 'chased' in the presence of glucose contained proportionately more unusual Man3GlcNAc2-size oligosaccharides. These small neutral-type oligosaccharides were apparently not as good a substrate for further processing into complex acidic-type oligosaccharides as the normal Man5GlcNAc2 intermediate that results from the full-size precursor oligosaccharides.

Short photoperiod-induced ovarian regression is mediated by apoptosis in Siberian hamsters (Phodopus sungorus)

PubMed Central

Moffatt-Blue, C S; Sury, J J; Young, Kelly A

2009-01-01

Siberian hamster reproduction is mediated by photoperiod-induced changes in gonadal activity. However, little is known about how photoperiod induces cellular changes in ovarian function. We hypothesized that exposing female hamsters to short (inhibitory) as opposed to long (control) photoperiods would induce an apoptosis-mediated disruption of ovarian function. Ovaries and plasma from hamsters exposed to either long (LD, 16 h light:8 h darkness) or short (SD, 8 h light:16 h darkness) days were collected during diestrus II after 3, 6, 9 and 12 weeks and processed for histology or RIA respectively. Apoptosis was assessed by in situ TUNEL and active caspase-3 protein immunolabeling. No significant differences were observed among LD hamsters for any parameter; therefore, these control data were pooled. SD exposure induced a decline in preantral follicles (P < 0.05), early antral/antral follicles (P < 0.01) and corpora lutea (P < 0.01) by week 12 as compared with LD. Terminal atretic follicles appeared by SD week 9; by week 12, these had become the predominant ovarian structures. Estradiol concentrations decreased by weeks 9 and 12 SD when compared with both LD and week-3 SD hamsters (P < 0.05); however, no changes were observed for progesterone. TUNEL-positive follicles in SD ovaries increased at week 3 and subsequently declined by week 12 as compared with LD ovaries (P < 0.01). Active capsase-3 protein immunostaining peaked at SD week 3 as compared with all other groups (P < 0.01). TUNEL and capsase-3 immunolabeling were localized to granulosa cells of late-preantral and early-antral/antral follicles. These data indicate that SD exposure rapidly induces follicular apoptosis in Siberian hamsters, which ultimately disrupts both estradiol secretion and folliculogenesis, resulting in the seasonal loss of ovarian function. PMID:16595728

Blood Vessel Normalization in the Hamster Oral Cancer Model for Experimental Cancer Therapy Studies

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

Ana J. Molinari; Romina F. Aromando; Maria E. Itoiz

Normalization of tumor blood vessels improves drug and oxygen delivery to cancer cells. The aim of this study was to develop a technique to normalize blood vessels in the hamster cheek pouch model of oral cancer. Materials and Methods: Tumor-bearing hamsters were treated with thalidomide and were compared with controls. Results: Twenty eight hours after treatment with thalidomide, the blood vessels of premalignant tissue observable in vivo became narrower and less tortuous than those of controls; Evans Blue Dye extravasation in tumor was significantly reduced (indicating a reduction in aberrant tumor vascular hyperpermeability that compromises blood flow), and tumor bloodmore » vessel morphology in histological sections, labeled for Factor VIII, revealed a significant reduction in compressive forces. These findings indicated blood vessel normalization with a window of 48 h. Conclusion: The technique developed herein has rendered the hamster oral cancer model amenable to research, with the potential benefit of vascular normalization in head and neck cancer therapy.« less

Southern Analysis of Genomic Alterations in Gamma-Ray-Induced Aprt- Hamster Cell Mutants

PubMed Central

Grosovsky, Andrew J.; Drobetsky, Elliot A.; deJong, Pieter J.; Glickman, Barry W.

1986-01-01

The role of genomic alterations in mutagenesis induced by ionizing radiation has been the subject of considerable speculation. By Southern blotting analysis we show here that 9 of 55 (approximately 1/6) gamma-ray-induced mutants at the adenine phosphoribosyl transferase (aprt) locus of Chinese hamster ovary (CHO) cells have a detectable genomic rearrangement. These fall into two classes: intragenic deletions and chromosomal rearrangements. In contrast, no major genomic alterations were detected among 67 spontaneous mutants, although two restriction site loss events were observed. Three gamma-ray-induced mutants were found to be intragenic deletions; all may have identical break-points. The remaining six gamma-ray-induced mutants demonstrating a genomic alteration appear to be the result of chromosomal rearrangements, possibly translocation or inversion events. None of the remaining gamma-ray-induced mutants showed any observable alteration in blotting pattern indicating a substantial role for point mutation in gamma-ray-induced mutagenesis at the aprt locus. PMID:3013724

Molecular analysis of peroxisome proliferation in the hamster.

PubMed

Choudhury, Agharul I; Sims, Helen M; Horley, Neill J; Roberts, Ruth A; Tomlinson, Simon R; Salter, Andrew M; Bruce, Mary; Shaw, P Nicholas; Kendall, David; Barrett, David A; Bell, David R

2004-05-15

Three novel P450 members of the cytochrome P450 4A family were cloned as partial cDNAs from hamster liver, characterised as novel members of the CYP4A subfamily, and designated CYP4A17, 18, and 19. Hamsters were treated with the peroxisome proliferator-activated receptor alpha (PPARalpha) agonists, methylclofenapate (MCP) or Wy-14,643, and shown to develop hepatomegaly and induction of CYP4A17 RNA, and concomitant induction of lauric acid 12- hydroxylase. This treatment also resulted in hypolipidaemia, which was most pronounced in the VLDL fraction, with up to 50% reduction in VLDL-triglycerides; by contrast, blood cholesterol concentration was unaffected by this treatment. These data show that hamster is highly responsive to induction of CYP4A by peroxisome proliferators. To characterise the molecular basis of peroxisome proliferation, the hamster PPARalpha was cloned and shown to encode a 468-amino-acid protein, which is highly similar to rat and mouse PPARalpha proteins. The level of expression of hamster PPARalpha in liver is intermediate between mouse and guinea pig. These results fail to support the hypothesis that the level of PPARalpha in liver is directly responsible for species differences in peroxisome proliferation.

Hamster and Murine Models of Severe Destructive Lyme Arthritis

PubMed Central

Munson, Erik; Nardelli, Dean T.; Du Chateau, Brian K.; Callister, Steven M.; Schell, Ronald F.

2012-01-01

Arthritis is a frequent complication of infection in humans with Borrelia burgdorferi. Weeks to months following the onset of Lyme borreliosis, a histopathological reaction characteristic of synovitis including bone, joint, muscle, or tendon pain may occur. A subpopulation of patients may progress to a chronic, debilitating arthritis months to years after infection which has been classified as severe destructive Lyme arthritis. This arthritis involves focal bone erosion and destruction of articular cartilage. Hamsters and mice are animal models that have been utilized to study articular manifestations of Lyme borreliosis. Infection of immunocompetent LSH hamsters or C3H mice results in a transient synovitis. However, severe destructive Lyme arthritis can be induced by infecting irradiated hamsters or mice and immunocompetent Borrelia-vaccinated hamsters, mice, and interferon-gamma- (IFN-γ-) deficient mice with viable B. burgdorferi. The hamster model of severe destructive Lyme arthritis facilitates easy assessment of Lyme borreliosis vaccine preparations for deleterious effects while murine models of severe destructive Lyme arthritis allow for investigation of mechanisms of immunopathology. PMID:22461836

Radiation damage and defect behavior in ion-implanted, lithium counterdoped silicon solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Mehta, S.; Swartz, C. K.

1984-01-01

Boron doped silicon n+p solar cells were counterdoped with lithium by ion implantation and the resuitant n+p cells irradiated by 1 MeV electrons. The function of fluence and a Deep Level Transient Spectroscopy (DLTS) was studied to correlate defect behavior with cell performance. It was found that the lithium counterdoped cells exhibited significantly increased radiation resistance when compared to boron doped control cells. It is concluded that the annealing behavior is controlled by dissociation and recombination of defects. The DLTS studies show that counterdoping with lithium eliminates at least three deep level defects and results in three new defects. It is speculated that the increased radiation resistance of the counterdoped cells is due primarily to the interaction of lithium with oxygen, single vacanies and divacancies and that the lithium-oxygen interaction is the most effective in contributing to the increased radiation resistance.

Radiation damage and defect behavior in ion-implanted, lithium counterdoped silicon solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Mehta, S.; Swartz, C. K.

1984-01-01

Boron doped silicon n+p solar cells were counterdoped with lithium by ion implanation and the resultant n+p cells irradiated by 1 MeV electrons. The function of fluence and a Deep Level Transient Spectroscopy (DLTS) was studied to correlate defect behavior with cell performance. It was found that the lithium counterdoped cells exhibited significantly increased radiation resistance when compared to boron doped control cells. It is concluded that the annealing behavior is controlled by dissociation and recombination of defects. The DLTS studies show that counterdoping with lithium eliminates at least three deep level defects and results in three new defects. It is speculated that the increased radiation resistance of the counterdoped cells is due primarily to the interaction of lithium with oxygen, single vacancies and divacancies and that the lithium-oxygen interaction is the most effective in contributing to the increased radiation resistance.

The adaptive immune response does not influence hantavirus disease or persistence in the Syrian hamster

PubMed Central

Prescott, Joseph; Safronetz, David; Haddock, Elaine; Robertson, Shelly; Scott, Dana; Feldmann, Heinz

2013-01-01

Pathogenic New World hantaviruses cause severe disease in humans characterized by a vascular leak syndrome, leading to pulmonary oedema and respiratory distress with case fatality rates approaching 40%. Hantaviruses infect microvascular endothelial cells without conspicuous cytopathic effects, indicating that destruction of the endothelium is not a mechanism of disease. In humans, high levels of inflammatory cytokines are present in the lungs of patients that succumb to infection. This, along with other observations, suggests that disease has an immunopathogenic component. Currently the only animal model available to study hantavirus disease is the Syrian hamster, where infection with Andes virus (ANDV), the primary agent of disease in South America, results in disease that closely mimics that seen in humans. Conversely, inoculation of hamsters with a passaged Sin Nombre virus (SNV), the virus responsible for most cases of disease in North America, results in persistent infection with high levels of viral replication. We found that ANDV elicited a stronger innate immune response, whereas SNV elicited a more robust adaptive response in the lung. Additionally, ANDV infection resulted in significant changes in the blood lymphocyte populations. To determine whether the adaptive immune response influences infection outcome, we depleted hamsters of CD4+ and CD8+ T cells before infection with hantaviruses. Depletion resulted in inhibition of virus-specific antibody responses, although the pathogenesis and replication of these viruses were unaltered. These data show that neither hantavirus replication, nor pathogenesis caused by these viruses, is influenced by the adaptive immune response in the Syrian hamster. PMID:23600567

Defect Genome of Cubic Perovskites for Fuel Cell Applications

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

Balachandran, Janakiraman; Lin, Lianshan; Anchell, Jonathan S.

Heterogeneities such as point defects, inherent to material systems, can profoundly influence material functionalities critical for numerous energy applications. This influence in principle can be identified and quantified through development of large defect data sets which we call the defect genome, employing high-throughput ab initio calculations. However, high-throughput screening of material models with point defects dramatically increases the computational complexity and chemical search space, creating major impediments toward developing a defect genome. In this paper, we overcome these impediments by employing computationally tractable ab initio models driven by highly scalable workflows, to study formation and interaction of various point defectsmore » (e.g., O vacancies, H interstitials, and Y substitutional dopant), in over 80 cubic perovskites, for potential proton-conducting ceramic fuel cell (PCFC) applications. The resulting defect data sets identify several promising perovskite compounds that can exhibit high proton conductivity. Furthermore, the data sets also enable us to identify and explain, insightful and novel correlations among defect energies, material identities, and defect-induced local structural distortions. Finally, such defect data sets and resultant correlations are necessary to build statistical machine learning models, which are required to accelerate discovery of new materials.« less

Defect Genome of Cubic Perovskites for Fuel Cell Applications

DOE PAGES

Balachandran, Janakiraman; Lin, Lianshan; Anchell, Jonathan S.; ...

2017-10-10

Heterogeneities such as point defects, inherent to material systems, can profoundly influence material functionalities critical for numerous energy applications. This influence in principle can be identified and quantified through development of large defect data sets which we call the defect genome, employing high-throughput ab initio calculations. However, high-throughput screening of material models with point defects dramatically increases the computational complexity and chemical search space, creating major impediments toward developing a defect genome. In this paper, we overcome these impediments by employing computationally tractable ab initio models driven by highly scalable workflows, to study formation and interaction of various point defectsmore » (e.g., O vacancies, H interstitials, and Y substitutional dopant), in over 80 cubic perovskites, for potential proton-conducting ceramic fuel cell (PCFC) applications. The resulting defect data sets identify several promising perovskite compounds that can exhibit high proton conductivity. Furthermore, the data sets also enable us to identify and explain, insightful and novel correlations among defect energies, material identities, and defect-induced local structural distortions. Finally, such defect data sets and resultant correlations are necessary to build statistical machine learning models, which are required to accelerate discovery of new materials.« less

Spindle disturbances in human-hamster hybrid (AL) cells induced by mobile communication frequency range signals.

PubMed

Schrader, Thorsten; Münter, Klaus; Kleine-Ostmann, Thomas; Schmid, Ernst

2008-12-01

The production of spindle disturbances in FC2 cells, a human-hamster hybrid (A(L)) cell line, by non-ionizing radiation was studied using an electromagnetic field with a field strength of 90 V/m at a frequency of 835 MHz. Due to the given experimental conditions slide flask cultures were exposed at room temperature in a microTEM (transversal electromagnetic field) cell, which allows optimal experimental conditions for small samples of biological material. Numerical calculations suggest that specific absorption rates of up to 60 mW/kg are reached for maximum field exposure. All exposure field parameters--either measured or calculable--are precisely defined and, for the first time, traceable to the standards of the SI system of physical units. Compared with co-incident negative controls, the results of two independently performed experiments suggest that exposure periods of time from 0.5 to 2 h with an electric field strength of 90 V/m are spindle acting agents as predominately indicated by the appearance of spindle disturbances at the ana- and telophase stages (especially lagging and non-disjunction of single chromosomes) of cell divisions. The spindle disturbances do not change the fraction of mitotic cells with increasing exposure time up to 2 h. Due to the applied experimental conditions an influence of temperature as a confounder parameter for spindle disturbances can be excluded.

Targeted transgene insertion into the CHO cell genome using Cre recombinase-incorporating integrase-defective retroviral vectors.

PubMed

Kawabe, Yoshinori; Shimomura, Takuya; Huang, Shuohao; Imanishi, Suguru; Ito, Akira; Kamihira, Masamichi

2016-07-01

Retroviral vectors have served as efficient gene delivery tools in various biotechnology fields. However, viral DNA is randomly inserted into the genome, which can cause problems, such as insertional mutagenesis and gene silencing. Previously, we reported a site-specific gene integration system, in which a transgene is integrated into a predetermined chromosomal locus of Chinese hamster ovary (CHO) cells using integrase-defective retroviral vectors (IDRVs) and Cre recombinase. In this system, a Cre expression plasmid is transfected into founder cells before retroviral transduction. In practical applications of site-specific gene modification such as for hard-to-transfect cells or for in vivo gene delivery, both the transgene and the Cre protein into retroviral virions should be encapsulate. Here, we generated novel hybrid IDRVs in which viral genome and enzymatically active Cre can be delivered (Cre-IDRVs). Cre-IDRVs encoding marker genes, neomycin resistance and enhanced green fluorescent protein (EGFP), flanked by wild-type and mutated loxP sites were produced using an expression plasmid for a chimeric protein of Cre and retroviral gag-pol. After analyzing the incorporation of the Cre protein into retroviral virions by Western blotting, the Cre-IDRV was infected into founder CHO cells, in which marker genes (hygromycin resistance and red fluorescent protein) flanked with corresponding loxP sites are introduced into the genome. G418-resistant colonies expressing GFP appeared and the site-specific integration of the transgene into the expected chromosomal site was confirmed by PCR and sequencing of amplicons. Moreover, when Cre-IDRV carried a gene expression unit for a recombinant antibody, the recombinant cells in which the antibody expression cassette was integrated in a site-specific manner were generated and the cells produced the recombinant antibody. This method may provide a promising tool to perform site-specific gene modification according to Cre

Characterization of the Host Response to Pichinde Virus Infection in the Syrian Golden Hamster by Species-Specific Kinome Analysis*

PubMed Central

Falcinelli, Shane; Gowen, Brian B.; Trost, Brett; Napper, Scott; Kusalik, Anthony; Johnson, Reed F.; Safronetz, David; Prescott, Joseph; Wahl-Jensen, Victoria; Jahrling, Peter B.; Kindrachuk, Jason

2015-01-01

The Syrian golden hamster has been increasingly used to study viral hemorrhagic fever (VHF) pathogenesis and countermeasure efficacy. As VHFs are a global health concern, well-characterized animal models are essential for both the development of therapeutics and vaccines as well as for increasing our understanding of the molecular events that underlie viral pathogenesis. However, the paucity of reagents or platforms that are available for studying hamsters at a molecular level limits the ability to extract biological information from this important animal model. As such, there is a need to develop platforms/technologies for characterizing host responses of hamsters at a molecular level. To this end, we developed hamster-specific kinome peptide arrays to characterize the molecular host response of the Syrian golden hamster. After validating the functionality of the arrays using immune agonists of defined signaling mechanisms (lipopolysaccharide (LPS) and tumor necrosis factor (TNF)-α), we characterized the host response in a hamster model of VHF based on Pichinde virus (PICV1) infection by performing temporal kinome analysis of lung tissue. Our analysis revealed key roles for vascular endothelial growth factor (VEGF), interleukin (IL) responses, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling, and Toll-like receptor (TLR) signaling in the response to PICV infection. These findings were validated through phosphorylation-specific Western blot analysis. Overall, we have demonstrated that hamster-specific kinome arrays are a robust tool for characterizing the species-specific molecular host response in a VHF model. Further, our results provide key insights into the hamster host response to PICV infection and will inform future studies with high-consequence VHF pathogens. PMID:25573744

A dual near-infrared and dielectric spectroscopies strategy to monitor populations of Chinese hamster ovary cells in bioreactor.

PubMed

Courtès, Franck; Ebel, Bruno; Guédon, Emmanuel; Marc, Annie

2016-05-01

to develop a new strategy combining near-infrared (NIR) and dielectric spectroscopies for real-time monitoring and in-depth characterizing populations of Chinese hamster ovary cells throughout cultures performed in bioreactors. Spectral data processing was based on off-line analyses of the cells, including trypan blue exclusion method, and lactate dehydrogenase activity (LDH). Viable cell density showed a linear correlation with permittivity up to 6 × 10(6) cells ml(-1), while a logarithmic correlation was found between non-lysed dead cell density and conductivity up to 10(7) cells ml(-1). Additionally, partial least square technique was used to develop a calibration model of the supernatant LDH activity based on online NIR spectra with a RMSEC of 55 U l(-1). Considering the LDH content of viable cells measured to be 110 U per 10(9) cells, the lysed dead cell density could be then estimated. These calibration models provided real-time prediction accuracy (R(2) ≥ 0.95) for the three types of cell populations. The high potential of a dual spectroscopy strategy to enhance the online bioprocesses characterization is demonstrated since it allows the simultaneous determination of viable, dead and lysed cell populations in real time.

Influence of deep defects on device performance of thin-film polycrystalline silicon solar cells

NASA Astrophysics Data System (ADS)

Fehr, M.; Simon, P.; Sontheimer, T.; Leendertz, C.; Gorka, B.; Schnegg, A.; Rech, B.; Lips, K.

2012-09-01

Employing quantitative electron-paramagnetic resonance analysis and numerical simulations, we investigate the performance of thin-film polycrystalline silicon solar cells as a function of defect density. We find that the open-circuit voltage is correlated to the density of defects, which we assign to coordination defects at grain boundaries and in dislocation cores. Numerical device simulations confirm the observed correlation and indicate that the device performance is limited by deep defects in the absorber bulk. Analyzing the defect density as a function of grain size indicates a high concentration of intra-grain defects. For large grains (>2 μm), we find that intra-grain defects dominate over grain boundary defects and limit the solar cell performance.

[The polyploidization characteristics of the hepatocytes of the mouse-like hamster Calomyscus mystax].

PubMed

Anatskaia, O V; Malikov, V G; Meĭer, M N; Kudriavtsev, B N

1995-01-01

A cytophotometric measurement of DNA content in hepatocytes of maturing mouse-like hamsters was made. Cells belonging to ordinary mammalian ploidy classes 2c, 2c x 2, 4c, and 4c x 2 made about 90% of the hepatocyte population. The share of binucleated cells wa high (about 80%), the majority of these cells being 2c X 2 hepatocytes. Binucleated cells with tetraploid and diploid nuclei occur in almost every animal. An average hepatocyte ploidy level in mouse-like hamster is 4.6c. The main peculiarity of parenchymal liver cell populations is that up 5% of hepatocytes contain 3--11 nuclei of different ploidy classes. Multinucleated cells increase in number from 1.5% to 4% within the period from one year (the age of maturation) to two years. Later on their percentage does not change. It is found that in binucleated and multinucleated hepatocytes DNA synthesis can proceed asynchronously. Asynchrony in DNA synthesis elevates as the number of nuclei increases. Among the 2c x 2 and 2c x 3 cells an uneven distribution of 3H-thymidine label can occur, respectively, in 5 and in 50% cases, whereas all the cells with more than 3 nuclei display an uneven an uneven 3H-thymidin label distribution. The formation of multinucleated cells is supposed to be associated with asynchrony in DNA-synthesis in binucleated cells and with the restitution of mitosis.

Alkaline phosphatases contribute to uterine receptivity, implantation, decidualization and defense against bacterial endotoxin in hamsters

PubMed Central

Lei, Wei; Nguyen, Heidi; Brown, Naoko; Ni, Hua; Kiffer-Moreira, Tina; Reese, Jeff; Millán, José Luis; Paria, Bibhash C.

2013-01-01

Alkaline phosphatase (AP) activity has been demonstrated in the uterus of several species, but its importance in the uterus, in general and during pregnancy, is yet to be revealed. In this study, we focused on identifying AP isozyme types, and their hormonal regulation, cell-type and event-specific expression and possible functions in the hamster uterus during the cycle and early pregnancy. Our RT-PCR and in situ hybridization studies demonstrated that among the known Akp2, Akp3, Akp5 and Akp6 murine AP isozyme genes, hamster uteri express only Akp2 and Akp6; and both genes are co-expressed in luminal epithelial cells. Studies in cyclic and ovariectomized hamsters established that while progesterone is the major uterine Akp2 inducer, both progesterone and estrogen are strong Akp6 regulators. Studies in preimplantation uteri showed induction of both genes and the activity of their encoded isozymes in luminal epithelial cells during uterine receptivity. However, at the beginning of implantation, Akp2 showed reduced expression in luminal epithelial cells surrounding the implanted embryo. In contrast, expression of Akp6 and its isozyme was maintained in luminal epithelial cells adjacent to, but not away from, the implanted embryo. Following implantation, stromal transformation to decidua was associated with induced expressions of only Akp2 and its isozyme. We next demonstrated that uterine APs dephosphorylate and detoxify endotoxin lipopolysaccharide at their sites of production and activity. Taken together, our findings suggest that uterine APs contribute to uterine receptivity, implantation, and decidualization in addition to their role in protection of the uterus and pregnancy against bacterial infection. PMID:23929901

Local adherent technique for transplanting mesenchymal stem cells as a potential treatment of cartilage defect.

PubMed

Koga, Hideyuki; Shimaya, Masayuki; Muneta, Takeshi; Nimura, Akimoto; Morito, Toshiyuki; Hayashi, Masaya; Suzuki, Shiro; Ju, Young-Jin; Mochizuki, Tomoyuki; Sekiya, Ichiro

2008-01-01

Current cell therapy for cartilage regeneration requires invasive procedures, periosteal coverage and scaffold use. We have developed a novel transplantation method with synovial mesenchymal stem cells (MSCs) to adhere to the cartilage defect. For ex vivo analysis in rabbits, the cartilage defect was faced upward, filled with synovial MSC suspension, and held stationary for 2.5 to 15 minutes. The number of attached cells was examined. For in vivo analysis in rabbits, an autologous synovial MSC suspension was placed on the cartilage defect, and the position was maintained for 10 minutes to adhere the cells to the defect. For the control, either the same cell suspension was injected intra-articularly or the defects were left empty. The three groups were compared macroscopically and histologically. For ex vivo analysis in humans, in addition to the similar experiment in rabbits, the expression and effects of neutralizing antibodies for adhesion molecules were examined. Ex vivo analysis in rabbits demonstrated that the number of attached cells increased in a time-dependent manner, and more than 60% of cells attached within 10 minutes. The in vivo study showed that a large number of transplanted synovial MSCs attached to the defect at 1 day, and the cartilage defect improved at 24 weeks. The histological score was consistently better than the scores of the two control groups (same cell suspension injected intra-articularly or defects left empty) at 4, 12, and 24 weeks. Ex vivo analysis in humans provided similar results to those in rabbits. Intercellular adhesion molecule 1-positive cells increased between 1 minute and 10 minutes, and neutralizing antibodies for intercellular adhesion molecule 1, vascular cell adhesion molecule 1 and activated leukocyte-cell adhesion molecule inhibited the attachment. Placing MSC suspension on the cartilage defect for 10 minutes resulted in adherence of >60% of synovial MSCs to the defect, and promoted cartilage regeneration. This

Isolation, antimicrobial activities, and primary structures of hamster neutrophil defensins.

PubMed Central

Mak, P; Wójcik, K; Thogersen, I B; Dubin, A

1996-01-01

Hamster (Mesocricetus auratus) neutrophil granules contain at least four microbicidal peptides belonging to the defensin family. These compounds were purified from granule acid extracts by reverse-phase chromatography and termed HaNP-1 to -4 (hamster neutrophil peptide). HaNP-1 and HaNP-3 revealed the most bactericidal activity, with a 50% inhibitory concentration of 0.3 to 0.8 microg/ml for Staphylococcus aureus and Streptococcus pyogenes strains. The HaNP-4 was always isolated in concentrations exceeding about 10 times the concentrations of other hamster peptides, but its antibacterial activity as well as that of HaNP-2 was relatively lower, probably as a result of conserved Arg residue substitutions. Other microorganisms were also tested, and generally, hamster defensins exhibited less potency against gram-negative bacteria. The amino acid sequence of hamster defensins showed a high percentage of identity to the sequence of mouse enteric defensins, reaching about 60% identical residues in the case of HaNP-3 and cryptdin 3. PMID:8890190

[Rabies in the common hamster (Cricetus cricetus) in Slovakia].

PubMed

Svrcek, S; Ondrejka, R; Mlynarcíková, K; Svec, J

1984-11-01

The trials were conducted within the full-scale research on the ecology of lyssa virus. In a period of the mass outbreak of common hamster population in the East Slovakian region, 283 hamsters were examined for rabies. Using the direct immunofluorescence method (DIFM), the rabies antigen was detected in the brain of five hamsters. Three virus strains (denoted as 3 O, 7 E, 9 E) were isolated by means of the inoculation test on sucking mice. On the basis of the detection of the nucleo-protein antigen by DIFM, or its inhibition, detection of the Babes-Negri bodies, determination of the neutralization index, titration on mice and determination of incubation time, the isolated strains were identified as the street strains of rabies virus. As determined by further detailed studies on biological characteristics (determination of the invasiveness index on animals with different susceptibility to rabies virus, determination of pathogenicity for different species of laboratory animals, different weight categories, with different methods of administration, invasiveness index), the "hamster" strains are included among those of intermediate virulence or reduced virulence. At intramuscular administration, the most virulent of the three "hamster" strains studied (3 O) induces a fatal course of rabies in common fox and cat; for wolves, dogs and rabbits it is apathogenic. This strain is also contained in the salivary glands of foxes and cats. In immunofluorescent detection of the rabies nucleoprotein antigen, the "hamster" strains formed a mixed picture of fluorescing particles, characteristic of street strains.

Absence of C-type natriuretic peptide receptors in hamster glomeruli.

PubMed

Luk, J K; Wong, E F; Wong, N L

1994-01-01

The distribution of atrial natriuretic peptide receptor B (ANPR-B) varies between tissues and species. The aim of this study is to determine whether ANPR-B is present in the hamster glomeruli. In vitro C-type natriuretic peptide (CNP)- and atrial natriuretic factor (ANF)-stimulated cGMP accumulation studies were performed in hamster glomeruli. Elevated cGMP accumulations were observed upon ANF addition. No cGMP response was seen with CNP. Competitive receptor-binding experiments were performed with 125I-CNP and 125I-ANF against their respective cold peptides in hamster glomeruli. Although no CNP binding was detected, positive ANF binding was found and two types of ANF receptor were demonstrated. The affinity (Kdl) and maximum binding capacity (Bmaxl) of the high-affinity ANF receptor were 0.014 +/- 0.001 nM and 60.4 +/- 10.2 fmol/mg protein, respectively. Those of the low-affinity receptor (Kd2 and Bmax2) were 45.7 +/- 6.2 nM and 28.3 +/- 6.3 pmol/mg protein, respectively. Similarly, saturation binding experiments also failed to show any CNP receptor binding in hamster glomeruli. This finding suggests that ANPR-B is not present in hamster glomeruli and CNP is not a direct physiological regulator of hamster renal function.

Mutation and repair in an ultraviolet-sensitive Chinese hamster ovary cell line

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

Wood, R.D.

1981-11-01

An ultraviolet (UV) light-sensitive mutant of Chinese hamster ovary cells (CHO) has been isolated and characterized with respect to a number of post-irradiation responses. The UV-sensitive mutant, termed 43-3B, has the same growth rate and chromosome number as the wild-type CHO-9. 43-3B is hypersensitive to the lethal effects of UV light (D/sub 0/ of 0.3 J/m/sup 2/ as compared to 3.2 J/m/sup 2/ for the wild-type). A marked UV-hypermutability is observed in 43-3B as compared to the wild-type, as measured with markers for induced resistance to 6-thioguanine, ouabain, and diphtheria toxin. A factor of 38 to 65 more mutations aremore » induced per unit fluence in 43-3B than in CHO-9. The UV-sensitive mutant is also sensitive to killing by simulated solar light, although the D/sub 0/ ratio is not as great as for germicidal UV. 43-3B exhibits only about 17% of the wild-type level of UV-stimulated DNA repair synthesis, as measured by autoradiography of G/sub 1/ phase cells. A much reduced ability to recover control rates of semiconservative DNA synthesis after UV irradiation was observed in the repair-deficient 43-3B cell line. Recovery of colony-forming ability between fractionated UV exposures was observed in the wild-type CHO-9, but little recovery was seen in 43-3B. The present investigation demonstrates that a sensitive/wild-type pair of CHO cell lines can be used in comparative studies to determine the involvement of repair in a wide range of post-irradiation phenomena.« less

Etoposide radiosensitizes p53-defective cholangiocarcinoma cell lines independent of their G2 checkpoint efficacies

PubMed Central

Hematulin, Arunee; Meethang, Sutiwan; Utapom, Kitsana; Wongkham, Sopit; Sagan, Daniel

2018-01-01

Radiotherapy has been accounted as the most comprehensive cancer treatment modality over the past few decades. However, failure of this treatment modality occurs in several malignancies due to the resistance of cancer cells to radiation. It was previously reported by the present authors that defective cell cycle checkpoints could be used as biomarkers for predicting the responsiveness to radiation in individual patients with cholangiocarcinoma (CCA). However, identification of functional defective cell cycle checkpoints from cells from a patient's tissues is cumbersome and not applicable in the clinic. The present study evaluated the radiosensitization potential of etoposide in p53-defective CCA KKU-M055 and KKU-M214 cell lines. Treatment with etoposide enhanced the responsiveness of two p53-defective CCA cell lines to radiation independent of G2 checkpoint function. In addition, etoposide treatment increased radiation-induced cell death without altering the dominant mode of cell death of the two cell lines. These findings indicate that etoposide could be used as a radiation sensitizer for p53-defective tumors, independent of the function of G2 checkpoint. PMID:29541168

Melatonin alleviates hyperthyroidism induced oxidative stress and neuronal cell death in hippocampus of aged female golden hamster, Mesocricetus auratus.

PubMed

Rao, Geeta; Verma, Rakesh; Mukherjee, Arun; Haldar, Chandana; Agrawal, Neeraj Kumar

2016-09-01

Oxidative stress is a well known phenomenon under hyperthyroid condition that induces various physiological and neural problems with a higher prevalence in females. We, therefore investigated the antioxidant potential of melatonin (Mel) on hyperthyroidism-induced oxidative stress and neuronal cell death in the hippocampus region of brain (cognition and memory centre) of aged female golden hamster, Mesocricetus auratus. Aged female hamsters were randomly divided into four experimental groups (n=7); group-I: control, group-II: Melatonin (5mgkg(-1)day(-1), i.p., for one week), group-III: Hyperthyroid (100μg kg(-1)day(-1), i.p., for two weeks) and group-IV- Hyper+Mel. Hormonal profiles (thyroid and melatonin), activity of antioxidant enzymes (SOD, CAT and GPX), lipid peroxidation level (TBARS) and the specific apoptotic markers (Bax/Bcl-2 ratio and Caspase-3) expression were evaluated. A significant increase in the profile of total thyroid hormone (tT3 and tT4) in hyperthyroidic group as compared to control while tT3 significantly decreased in melatonin treated hyperthyroidic group. However, Mel level significantly decreased in hyperthyroidic group but increased in melatonin treated hyperthyroidic group. Further, the number of immune-positive cells for thyroid hormone receptor-alpha (TR-α) decreased in the hippocampus of hyperthyroidic group and increased in melatonin treated hyperthyroidic group. Profiles of antioxidant enzymes showed a significant decrease in hyperthyroidic group with a simultaneous increase in lipid peroxidation (TBARS). Melatonin treatment to hyperthyroidic group lead to decreased TBARS level with a concomitant increase in antioxidant enzyme activity. Moreover, increased expression of Bax/Bcl-2 ratio and Caspase-3, in hyperthyroidic group had elevated neuronal cell death in hippocampal area and melatonin treatment reduced its expression in hyperthyroidic group. Our findings thus indicate that melatonin reduced the hyperthyroidism

Histopathology of Lyme arthritis in LSH hamsters

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

Hejka, A.; Schmitz, J.L.; England, D.M.

1989-05-01

The authors studied the histopathologic evolution of arthritis in nonirradiated and irradiated hamsters infected with Borrelia burgdorferi. Nonirradiated hamsters injected in the hind paws with B. burgdorferi developed an acute inflammatory reaction involving the synovium, periarticular soft tissues, and dermis. This acute inflammatory reaction was short-lived and was replaced by a mild chronic synovitis as the number of detectable spirochetes in the synovium, periarticular soft tissues, and perineurovascular areas diminished. Exposing hamsters to radiation before inoculation with B. burgdorferi exacerbated and prolonged the acute inflammatory phase. Spirochetes also persisted longer in the periarticular soft tissues. A major histopathologic finding wasmore » destructive and erosive bone changes of the hind paws, which resulted in deformation of the joints. These studies should be helpful in defining the immune mechanism participating in the onset, progression, and resolution of Lyme arthritis.« less

The adaptive immune response does not influence hantavirus disease or persistence in the Syrian hamster.

PubMed

Prescott, Joseph; Safronetz, David; Haddock, Elaine; Robertson, Shelly; Scott, Dana; Feldmann, Heinz

2013-10-01

Pathogenic New World hantaviruses cause severe disease in humans characterized by a vascular leak syndrome, leading to pulmonary oedema and respiratory distress with case fatality rates approaching 40%. Hantaviruses infect microvascular endothelial cells without conspicuous cytopathic effects, indicating that destruction of the endothelium is not a mechanism of disease. In humans, high levels of inflammatory cytokines are present in the lungs of patients that succumb to infection. This, along with other observations, suggests that disease has an immunopathogenic component. Currently the only animal model available to study hantavirus disease is the Syrian hamster, where infection with Andes virus (ANDV), the primary agent of disease in South America, results in disease that closely mimics that seen in humans. Conversely, inoculation of hamsters with a passaged Sin Nombre virus (SNV), the virus responsible for most cases of disease in North America, results in persistent infection with high levels of viral replication. We found that ANDV elicited a stronger innate immune response, whereas SNV elicited a more robust adaptive response in the lung. Additionally, ANDV infection resulted in significant changes in the blood lymphocyte populations. To determine whether the adaptive immune response influences infection outcome, we depleted hamsters of CD4(+) and CD8(+) T cells before infection with hantaviruses. Depletion resulted in inhibition of virus-specific antibody responses, although the pathogenesis and replication of these viruses were unaltered. These data show that neither hantavirus replication, nor pathogenesis caused by these viruses, is influenced by the adaptive immune response in the Syrian hamster. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Modeling and experimental methods to predict oxygen distribution in bone defects following cell transplantation.

PubMed

Heylman, Christopher M; Santoso, Sharon; Krebs, Melissa D; Saidel, Gerald M; Alsberg, Eben; Muschler, George F

2014-04-01

We have developed a mathematical model that allows simulation of oxygen distribution in a bone defect as a tool to explore the likely effects of local changes in cell concentration, defect size or geometry, local oxygen delivery with oxygen-generating biomaterials (OGBs), and changes in the rate of oxygen consumption by cells within a defect. Experimental data for the oxygen release rate from an OGB and the oxygen consumption rate of a transplanted cell population are incorporated into the model. With these data, model simulations allow prediction of spatiotemporal oxygen concentration within a given defect and the sensitivity of oxygen tension to changes in critical variables. This information may help to minimize the number of experiments in animal models that determine the optimal combinations of cells, scaffolds, and OGBs in the design of current and future bone regeneration strategies. Bone marrow-derived nucleated cell data suggest that oxygen consumption is dependent on oxygen concentration. OGB oxygen release is shown to be a time-dependent function that must be measured for accurate simulation. Simulations quantify the dependency of oxygen gradients in an avascular defect on cell concentration, cell oxygen consumption rate, OGB oxygen generation rate, and OGB geometry.

The effect of pinealectomy, melatonin and leptin hormones on ovarian follicular development in female Syrian hamsters (Mesocricetus auratus).

PubMed

Karakaş, A; Kaya, Aliye; Gündüz, B

2010-12-01

We studied the effects of melatonin and leptin hormones on ovarian follicular development in intact and pinealectomized female Syrian hamsters. We first monitored the oestrous cycle of the hamsters by the vaginal smear samples throughout a ten day period to start the injections simultaneously in all groups and performed saline, melatonin and leptin hormone injection groups for both control and pinealectomized hamsters. Then the injections were applied for four days starting the oestrus phase of the cycle and the ovaries were removed for preparation of histological analysis. We measured the diameters and the numbers of the follicles and we classified the follicles according to the number of the granulosa cell layer. Leptin hormone injection increased melatonin hormone injection decreased the number and the diameter of the follicles. The stimulating effect of the leptin hormone was more pronounced in the pinealectomized group. The results of the present study indicate that the removal of the pineal gland and leptin hormone administration are playing a stimulatory while melatonin hormone administration is playing an inhibitory role on the follicular development in female Syrian hamsters.

Repair of full-thickness cartilage defects with cells of different origin in a rabbit model.

PubMed

Yan, Hui; Yu, Changlong

2007-02-01

The purpose of this study was to evaluate the repaired tissues formed in full-thickness cartilage defects in a rabbit model implanted with 4 types of chondrogenic cells, including chondrocytes, mesenchymal stem cells (MSCs) and fibroblasts from rabbit, and human umbilical cord blood (hUCB) stem cells. Chondrocytes, MSCs, and fibroblasts were isolated from 6-week-old New Zealand rabbits; hUCB stem cells were isolated from the umbilical cord blood of newborn children. These 4 types of cells were cultured in vitro and embedded in polylactic acid (PLA) matrices. Full-thickness defects were produced in the femoral trochlear grooves of both knees in 36 adult New Zealand White rabbits. Cell/PLA composites were transplanted into cartilage defects. A total of 5 groups were formed according to implanted cell type: Group A, chondrocytes; Group B, MSCs; Group C, fibroblasts; Group D, hUCB stem cells; and Group E, no cells (control group). Repaired tissues were evaluated grossly, histologically, and immunohistochemically at 6 weeks and 12 weeks after implantation. In Groups A and B, defects were repaired with hyaline-like cartilage. In Group C, defects were repaired with fibrous tissue. In Group D, defects were repaired primarily with fibrous tissue and scattered chondrocytes; in some specimens, defects were repaired with a thin layer of hyaline-like cartilage at 12 weeks. In Group E, defects were repaired with fibrous tissue. Histologic scores in Groups A and B were significantly higher than those in Groups C, D, and E at 6 and 12 weeks after transplantation. Full-thickness cartilage defects treated with chondrocyte or MSC transplantation were repaired with hyaline-like cartilage tissue, and repair was significantly better than in tissues treated with fibroblasts and hUCB stem cells, as well as in the control group. Repaired tissues treated with MSCs appeared to have better cell arrangement, subchondral bone remodeling, and integration with surrounding cartilage than did

The Syrian hamster model of hantavirus pulmonary syndrome.

PubMed

Safronetz, David; Ebihara, Hideki; Feldmann, Heinz; Hooper, Jay W

2012-09-01

Hantavirus pulmonary syndrome (HPS) is a relatively rare, but frequently fatal disease associated with New World hantaviruses, most commonly Sin Nombre and Andes viruses in North and South America, respectively. It is characterized by fever and the sudden, rapid onset of severe respiratory distress and cardiogenic shock, which can be fatal in up to 50% of cases. Currently there are no approved antiviral therapies or vaccines for the treatment or prevention of HPS. A major obstacle in the development of effective medical countermeasures against highly pathogenic agents like the hantaviruses is recapitulating the human disease as closely as possible in an appropriate and reliable animal model. To date, the only animal model that resembles HPS in humans is the Syrian hamster model. Following infection with Andes virus, hamsters develop HPS-like disease which faithfully mimics the human condition with respect to incubation period and pathophysiology of disease. Perhaps most importantly, the sudden and rapid onset of severe respiratory distress observed in humans also occurs in hamsters. The last several years has seen an increase in studies utilizing the Andes virus hamster model which have provided unique insight into HPS pathogenesis as well as potential therapeutic and vaccine strategies to treat and prevent HPS. The purpose of this article is to review the current understanding of HPS disease progression in Syrian hamsters and discuss the suitability of utilizing this model to evaluate potential medical countermeasures against HPS. Copyright © 2012 Elsevier B.V. All rights reserved.

The Syrian hamster model of hantavirus pulmonary syndrome

PubMed Central

Safronetz, David; Ebihara, Hideki; Feldmann, Heinz; Hooper, Jay W.

2012-01-01

Hantavirus pulmonary syndrome (HPS) is a relatively rare, but frequently fatal disease associated with New World hantaviruses, most commonly Sin Nombre and Andes viruses in North and South America, respectively. It is characterized by fever and the sudden, rapid onset of severe respiratory distress and cardiogenic shock, which can be fatal in up to 50% of cases. Currently there are no approved antiviral therapies or vaccines for the treatment or prevention of HPS. A major obstacle in the development of effective medical countermeasures against highly pathogenic agents like the hantaviruses is recapitulating the human disease as closely as possible in an appropriate and reliable animal model. To date, the only animal model that resembles HPS in humans is the Syrian hamster model. Following infection with Andes virus, hamsters develop HPS-like disease which faithfully mimics the human condition with respect to incubation period and pathophysiology of disease. Perhaps most importantly, the sudden and rapid onset of severe respiratory distress observed in humans also occurs in hamsters. The last several years has seen an increase in studies utilizing the Andes virus hamster model which have provided unique insight into HPS pathogenesis as well as potential therapeutic and vaccine strategies to treat and prevent HPS. The purpose of this article is to review the current understanding of HPS disease progression in Syrian hamsters and discuss the suitability of utilizing this model to evaluate potential medical countermeasures against HPS. PMID:22705798

Production of chimeric recombinant single domain antibody-green fluorescent fusion protein in Chinese hamster ovary cells.

PubMed

Bazl, M Rajabi; Rasaee, M J; Foruzandeh, M; Rahimpour, A; Kiani, J; Rahbarizadeh, F; Alirezapour, B; Mohammadi, M

2007-02-01

There is an increasing interest in the application of nanobodies such as VHH in the field of therapy and imaging. In the present study a stable genetically engineered cell line of Chinese hamster ovary (CHO) origin transfected using two sets of expression vectors was constructed in order to permit the cytoplasmic and extracellular expression of single domain antibody along with green fluorescent protein (GFP) as reporter gene. The quality of the constructs were examined both by the restriction map as well as sequence analysis. The gene transfection and protein expression was further examined by reverse transcription-polymerase chain reaction (RT-PCR). The transfected cells were grown in 200 microg/mL hygromycin containing media and the stable cell line obtained showed fluorescent activity for more than a period of 180 days. The production of fusion protein was also detected by fluorescent microscopy, fluorescent spectroscopy as well as by enzyme-linked immunosorbent assay (ELISA) analysis. This strategy allows a rapid production of recombinant fluobodies involving VHH, which can be used in various experiments such as imaging and detection in which a primary labeled antibody is required.

Morphological features (defects) in fuel cell membrane electrode assemblies

NASA Astrophysics Data System (ADS)

Kundu, S.; Fowler, M. W.; Simon, L. C.; Grot, S.

Reliability and durability issues in fuel cells are becoming more important as the technology and the industry matures. Although research in this area has increased, systematic failure analysis, such as a failure modes and effects analysis (FMEA), are very limited in the literature. This paper presents a categorization scheme of causes, modes, and effects related to fuel cell degradation and failure, with particular focus on the role of component quality, that can be used in FMEAs for polymer electrolyte membrane (PEM) fuel cells. The work also identifies component defects imparted on catalyst-coated membranes (CCM) by manufacturing and proposes mechanisms by which they can influence overall degradation and reliability. Six major defects have been identified on fresh CCM materials, i.e., cracks, orientation, delamination, electrolyte clusters, platinum clusters, and thickness variations.

Photoluminescence Imaging and LBIC Characterization of Defects in mc-Si Solar Cells

NASA Astrophysics Data System (ADS)

Sánchez, L. A.; Moretón, A.; Guada, M.; Rodríguez-Conde, S.; Martínez, O.; González, M. A.; Jiménez, J.

2018-05-01

Today's photovoltaic market is dominated by multicrystalline silicon (mc-Si) based solar cells with around 70% of worldwide production. In order to improve the quality of the Si material, a proper characterization of the electrical activity in mc-Si solar cells is essential. A full-wafer characterization technique such as photoluminescence imaging (PLi) provides a fast inspection of the wafer defects, though at the expense of the spatial resolution. On the other hand, a study of the defects at a microscopic scale can be achieved through the light-beam induced current technique. The combination of these macroscopic and microscopic resolution techniques allows a detailed study of the electrical activity of defects in mc-Si solar cells. In this work, upgraded metallurgical-grade Si solar cells are studied using these two techniques.

Inhibitory effects of Zengshengping fractions on DMBA-induced buccal pouch carcinogenesis in hamsters.

PubMed

Guan, Xiao-Bing; Sun, Zheng; Chen, Xiao-Xin; Wu, Hong-Ru; Zhang, Xin-Yan

2012-01-01

Zengshengping (ZSP) tablets had inhibitory effects on oral precancerous lesions by reducing the incidence of oral cancer. However, the severe liver toxicity caused by systemic administration of ZSP limits the long-term use of this anti-cancer drug. The purpose of this study was to evaluate the tumor inhibitory effects due to the topical application of extracts from ZSP, a Chinese herbal drug, on 7, 12-dimethlbenz(a)anthracene (DMBA) induced oral tumors in hamsters. The study also investigated the anti-cancer mechanisms of the ZSP extracts on oral carcinogenesis. DMBA (0.5%) was applied topically to the buccal pouches of Syrian golden hamsters (6 - 8 weeks old) three times per week for six weeks in order to induce the development of oral tumors. Different fractions of ZSP were either applied topically to the oral tumor lesions or fed orally at varying dosages to animals with oral tumors for 18 weeks. Tumor volume was measured by histopathological examination. Tumor cell proliferation was evaluated by counting BrdU labeled cells and by Western blotting for mitogen-activated protein kinase (MAPK) protein levels. The protein levels of apoptosis marker Caspase-3 and regulator Bcl-2 protein were also measured by Western blotting. Topical application of DMBA to the left pouch of hamsters induced oral tumor formation. Animals treated with DMBA showed a loss in body weight while animals treated with ZSP maintained normal body weights. Both the ZSP n-butanol fraction and water fraction significantly reduced tumor volume by 32.6% (P < 0.01) and 22.9% (P < 0.01) respectively. Topical application of ZSP also markedly decreased the BrdU-positive cell numbers in oral tumor lesions and reduced the expression level of MAPK. In addition, ZSP promoted tumor cell apoptosis by increasing Caspase-3 expression but decreasing Bcl-2 protein production. The n-butanol and water fractions of ZSP are effective at inhibiting tumor cell proliferation and stimulating apoptosis in oral cancer

[Toxic effect of trichloroethylene on liver cells with CYP3A4 gene defect].

PubMed

Liao, R Y; Liu, S

2016-06-20

To investigate the toxic effect of trichloroethylene on liver cells with CYP3A4 gene defect. The normal human liver cells (L02 cells) and liver cells with CYP3A4 gene defect were exposed to trichloroethylene at different doses (0.0, 0.4, 0.8, 1.6, 3.2, and 6.4 mmol/L). CCK8 assay and RT-qPCR were used to measure cell viability and changes in the expression of apoptosis genes and oncogenes. After being exposed to trichloroethylene at doses of 1.6, 3.2, and 6.4 mmol/L, the liver cells with CYP3A4 gene defect showed significantly higher cell viability than L02 cells (0.91±0.06/0.89±0.05/0.85±0.07 vs 0.80±0.04/0.73±0.06/0.67±0.07, P<0.05). The L02 cells in the 0.8~3.2 mmol/L trichloroethylene groups showed significant increases in the expression of the apoptosis genes caspase-3, caspase-8, and caspase-9 (P<0.05) , as well as the oncogenes c-myc, c-fos, and k-ras (P<0.05). Compared with the L02 cells, the cells with CYP3A4 gene defect showed significant reductions in the expression of the apoptosis genes caspase-3, caspase-8, and caspase-9 and the oncogenes c-myc, c-fos, and k-ras (P<0.05). Trichloroethylene exposure has a less effect on the expression of apoptosis genes and oncogenes in liver cells with CYP3A4 gene defect than in normal human liver cells, suggesting that CYP3A4 gene defect reduces the inductive effect of trichloroethylene on apoptosis genes and oncogenes.

Intrinsic and extrinsic contributors to defective CD8+ T cell responses with aging.

PubMed

Jergović, Mladen; Smithey, Megan J; Nikolich-Žugich, Janko

2018-05-01

Aging has a profound effect on the immune system, and both innate and adaptive arms of the immune system show functional decline with age. In response to infection with intracellular microorganisms, old animals mobilize decreased numbers of antigen-specific CD8+ T cells with reduced production of effector molecules and impaired cytolytic activity. However, the CD8+ T cell-intrinsic contribution to, and molecular mechanisms behind, these defects remain unclear. In this review we will discuss the mechanistic contributions of age related changes in the CD8+ T cell pool and the relative roles of intrinsic functional defects in aged CD8+ T cells vs. defects in the aged environment initiating the CD8+ T cell response. Copyright © 2018 Elsevier Inc. All rights reserved.

Endogenous ADP-ribosylation of elongation factor 2 in polyoma virus-transformed baby hamster kidney cells

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

Fendrick, J.L.; Iglewski, W.J.

1989-01-01

Polyoma virus-transformed baby hamster kidney (pyBHK) cells were cultured in medium containing ({sup 32}P)orthophosphate and 105 (vol/vol) fetal bovine serum. A {sup 32}P-labeled protein with an apparent molecular mass of 97 kDa was immunoprecipitated from cell lysates with antiserum to ADP-ribosylated elongation factor 2 (EF-2). The {sup 32}P labeling of the protein was enhanced by culturing cells in medium containing 2% serum instead of 10% serum. The {sup 32}P label was completely removed from the protein by treatment with snake venom phosphodiesterase and the digestion product was identified as ({sup 32}P)AMP, indicating the protein was mono-ADP-ribosylated. HPLC analysis of trypticmore » peptides of the {sup 32}P-labeled 97-kDa protein and purified EF-2, which was ADP-ribosylated in vitro with diphtheria toxin fragment A and ({sup 32}P)NAD, demonstrated an identical labeled peptide in the two proteins. The data strongly suggest that EF-2 was endogenously ADP-ribosylated in pyBHK cells. Maximum incorporation of radioactivity in EF-2 occurred by 12 hr and remained constant over the subsequent 12 hr. It was estimated that 30-35% of the EF-2 was ADP-ribosylated in cells cultured in medium containing 2% serum. When {sup 32}P-labeled cultures were incubated in medium containing unlabeled phosphate, the {sup 32}P label was lost from the EF-2 within 30 min.« less

Progressive proliferative and dysplastic typhlocolitis in aging syrian hamsters naturally infected with Helicobacter spp.: a spontaneous model of inflammatory bowel disease.

PubMed

Nambiar, P R; Kirchain, S M; Courmier, K; Xu, S; Taylor, N S; Theve, E J; Patterson, M M; Fox, J G

2006-01-01

Helicobacter spp. have been implicated in a variety of gastrointestinal tract diseases, including peptic ulcer disease, gastric cancer, and inflammatory bowel disease (IBD), in humans and animals. Although most models of IBD are experimentally induced, spontaneous or natural models of IBD are rare. Herein, we describe a long-term study of chronic, progressive lesions that develop in the distal portion of the large bowel of unmanipulated Syrian hamsters naturally infected with Helicobacter spp. Twenty-four Syrian hamsters of three age groups (group A, 1 month [n = 4], group B, 7-12 months [n = 12], group C, 18-24 months [n = 12]), underwent complete postmortem examination. Results of microbial isolation and polymerase chain reaction and restriction fragment length polymorphism analyses confirmed the presence of Helicobacter spp. infection in the distal portion of the large bowel of all animals. Additionally, confounding pathogens, such as Clostridium difficile, Lawsonia intracellularis, and Giardia spp. that can cause proliferative enteritis, were absent in the hamsters of this study. Histopathologic scores for inflammation (P < 0.01), hyperplasia (P < 0.01), and dysplasia (P < 0.05) were significantly higher in the ileocecocolic (ICC) junction of animals in group C, relative to group A. Dysplastic lesions of various grades were detected in 5 of 11 hamsters in group C. Interestingly, the segment of the bowel that is usually colonized by Helicobacter spp. in hamsters had the most severe lesions. One hamster of group C developed a malignant fibrous histiocytoma, whereas another hamster developed a round cell sarcoma originating from the ICC junction. Thus, lesions in the distal portion of the large bowel of aging hamsters naturally colonized with Helicobacter spp. warrants developing the hamster as an animal model of IBD and potentially IBD-related cancer.

The Use of Transcription Terminators to Generate Transgenic Lines of Chinese Hamster Ovary Cells (CHO) with Stable and High Level of Reporter Gene Expression.

PubMed

Gasanov, N B; Toshchakov, S V; Georgiev, P G; Maksimenko, O G

2015-01-01

Mammalian cell lines are widely used to produce recombinant proteins. Stable transgenic cell lines usually contain many insertions of the expression vector in one genomic region. Transcription through transgene can be one of the reasons for target gene repression after prolonged cultivation of cell lines. In the present work, we used the known transcription terminators from the SV40 virus, as well as the human β- and γ-globin genes, to prevent transcription through transgene. The transcription terminators were shown to increase and stabilize the expression of the EGFP reporter gene in transgenic lines of Chinese hamster ovary (CHO) cells. Hence, transcription terminators can be used to create stable mammalian cells with a high and stable level of recombinant protein production.

Regional assignment of seven genes on chromosome 1 of man by use of man-Chinese hamster somatic cell hybrids. II. Results obtained after induction of breaks in chromosome 1 by X-irradiation.

PubMed

Burgerhout, W G; Smit, S L; Jongsma, A P

1977-01-01

The position of genes coding for PGD, PPH1, UGPP, GuK1, PGM1, Pep-C, and FH on human chromosome 1 was investigated by analysis of karyotype and enzyme phenotypes in man-Chinese hamster somatic cell hybrids carrying aberrations involving chromosome 1. Suitable hybrid cell lines were obtained by X-irradiation of hybrid cells carrying an intact chromosome 1 and by fusion of human cells from a clonal population carrying a translocation involving chromosome 1 with Chinese hamster cells. The latter human cell population had been isolated following X-irradiation of primary Lesch-Nyhan fibroblasts. In addition, products of de novo chromosome breakage in the investigated hybrid lines were utilized. By integrating the results of these analyses with earlier findings in our laboratory, the following positions of genes are deduced: PGD and PPH1 in 1p36 leads to 1p34; PGM1 in 1p32; UGPP in 1q21 leads to 1q23; GuK1 in 1q31 leads to 1q42; Pep-C in 1q42; and FH in 1qter leads to 1q42.

Chemopreventive effect of Toona sinensis leaf extract on 7,12-dimethylbenz[a]anthracene-induced hamster buccal pouch squamous cell carcinogenesis.

PubMed

Wang, Wen-Chen; Chen, Ching-Yi; Hsu, Hseng-Kuang; Lin, Li-Min; Chen, Yuk-Kwan

2016-10-01

Toona sinensis leaf extract (TSL) has been shown to have anti-tumor effects on cancer cell lines. This study aimed to investigate the chemopreventive potential and the underlying mechanism of TSL during 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis. One hundred hamsters were divided into control (n=30), carcinogenic (n=20), preventive (n=42), and therapeutic (n=8) groups. The animals in carcinogenic and preventive groups were administered reverse osmosis water (carcinogenic group) or TSL (1g/kg bw) (preventive group) by gavage daily for 4 weeks, and their bilateral pouches were painted with a 0.5% DMBA solution for 4, 9, and 12 weeks. The animals in the therapeutic group were treated with DMBA for 12 weeks prior to TSL administration for 4 weeks. Expression levels of survivin, X chromosome-linked inhibitor of apoptosis (XIAP), proliferating cell nuclear antigen (PCNA), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) proteins were analyzed by immunohistochemistry. Apoptotic activity was examined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method, cytochrome C, and poly (ADP-ribose) polymerase (PARP). In the preventive group, the results showed significant decreases not only in the incidences of squamous cell carcinoma (SCC) (50%) and epithelial dysplasia (62.5%) but also in the tumor number, tumor volume, tumor burden, and the severity of dysplastic lesions. The down-regulation of survivin, XIAP, PCNA, iNOS, and COX-2 proteins and the increased apoptotic activity indicated anti-proliferative and apoptosis-inducing abilities of TSL on DMBA-induced HBP carcinogenesis. The results suggested that TSL might be a promising candidate for the prevention of oral cancer. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation with mTHPC of early squamous cell carcinomas of the cheek pouch mucosa of Golden Syrian hamsters as a model for clinical PDT of early cancers in the upper aerodigestive tract, the esophag

NASA Astrophysics Data System (ADS)

Glanzmann, Thomas M.; Theumann, Jean-Francois; Forrer, Martin; Braichotte, Daniel; Wagnieres, Georges A.; van den Bergh, Hubert; Andrejevic-Blant, Snezana; Savary, Jean-Francois; Monnier, Philippe

1995-03-01

Golden Syrian hamsters are evaluated as an animal model for light induced fluorescence (LIF) photodetection and phototherapy of early squamous cell carcinomas of the upper aerodigestive tract, the esophagus, and the traecheo-bronchial tree. Carcinomas of this type are induced on the hamster cheek pouch mucosa by the application of the carcinogen 7,12-DMBA. For phototherapeutic experiments on the animals we utilized meso-(tetrahydoxyphenyl) chlorin (mTHPC). This drug is currently in phase I and II clinical trials for ENT patients presenting superficial `early' squamous cell carcinomas. By means of LIF we measured in vivo the kinetics of the uptake and removal of mTHPC in the normal and tumoral cheek mucosa and in the skin. The photodynamic therapy (PDT) reaction of the tissue after excitation of the photosensitizer with laser light at 652 nm was studied. Both pharmacokinetics and PDT efficacy are compared between animal model and clinical results with special emphasis on selectivity between normal and tumoral mucosa. These first experiments show that this tumor model in the hamster cheek pouch seems to be suitable for testing new photosensitizers preceding their clinical application as well as for optimization of the multiple parameters of clinical PDT.

Topical photosan-mediated photodynamic therapy for DMBA-induced hamster buccal pouch premaligant lesions: an in vivo study

NASA Astrophysics Data System (ADS)

Hsu, Yih-Chih; Chiang, Chun-Pin; Chen, Jian Wen; Chen, Ying-Ru; Lee, Jeng-Woei

2010-02-01

One of the best strategies to prevent the occurrence of oral cancer is to eliminate oral precancers and block their further malignant transformation. Previous studies showed that photosan-mediated photodynamic therapy (photosan-PDT) is very effective for human head and neck cancers. To avoid the systemic photodynamic toxicity of photosan, this study was designed to use a topical photosan-PDT for treatment of DMBA-induced hamster buccal pouch precancerous lesions. Twelve 10-week-old male Syrian golden hamsters were used in this study. DMBA was applied to the left buccal pouches thrice a week for 8 to 10 weeks and mineral oil was painted on the right buccal pouches thrice a week for 8 to 10 weeks as the normal controls. Six hamsters were euthanized for tissue harvest. Precancerous lesions of moderate to severe dysplasia were consistently induced and proven by histological examination. These induced precancerous lesions in the remaining 6 hamsters were used for testing the efficacy of topical photosan-PDT. Before PDT, fluorescence spectroscopy was used to determine when protoporphyrine IX (PpIX) reached its peak level in the lesional epithelial cells after topical application of photosan-gel. We found that PpIX reached its peak level in precancerous lesions about 13.5 min after topical application of photosan-gel. The precancerous lesions in 4 hamsters were treated with topical photosan-PDT using the 635-nm LED light once or twice a week. Complete regression of the precancerous lesions was found after 2-4 PDT treatments by visual and histological examination. Our findings indicate that topical photosan-PDT is a very effective treatment modality for DMBA-induced hamster buccal pouch precancerous lesions.

Metabolic influences on circadian rhythmicity in Siberian and Syrian hamsters exposed to long photoperiods.

PubMed

Challet, E; Kolker, D E; Turek, F W

2000-01-01

Calorie restriction and other situations of reduced glucose availability in rodents alter the entraining effects of light on the circadian pacemaker located in the suprachiasmatic nuclei. Siberian and Syrian hamsters are photoperiodic species that are sexually active when exposed to long summer-like photoperiods, while both species show opposite changes in body mass when transferred from long to short or short to long days. Because metabolic cues may fine tune the photoperiodic responses via the suprachiasmatic nuclei, we tested whether timed calorie restriction can alter the photic synchronization of the light-entrainable pacemaker in these two hamster species exposed to long photoperiods. Siberian and Syrian hamsters were exposed to 16 h:8 h light:dark cycles and received daily hypocaloric (75% of daily food intake) or normocaloric diet (100% of daily food intake) 4 h after light onset. Four weeks later, hamsters were transferred to constant darkness and fed ad libitum. The onset of the nocturnal pattern of locomotor activity was phase advanced by 1.5 h in calorie-restricted Siberian hamsters, but not in Syrian hamsters. The lack of phase change in calorie-restricted Syrian hamsters was also observed in individuals exposed to 14 h:10 h dim light:dark cycles and fed with lower hypocaloric food (i.e. 60% of daily food intake) 2 h after light onset. Moreover, in hamsters housed in constant darkness and fed ad lib., light-induced phase shifts of the locomotor activity in Siberian hamsters, but not in Syrian hamsters were significantly reduced when glucose utilization was blocked by pretreatment with 500 mg/kg i.p. 2-deoxy-D-glucose. Taken together, these results show that the photic synchronization of the light-entrainable pacemaker can be modulated by metabolic cues in Siberian hamsters, but not in Syrian hamsters maintained on long days.

A lethal disease model for New World hantaviruses using immunosuppressed Syrian hamsters.

PubMed

Vergote, Valentijn; Laenen, Lies; Vanmechelen, Bert; Van Ranst, Marc; Verbeken, Erik; Hooper, Jay W; Maes, Piet

2017-10-01

Hantavirus, the hemorrhagic causative agent of two clinical diseases, is found worldwide with variation in severity, incidence and mortality. The most lethal hantaviruses are found on the American continent where the most prevalent viruses like Andes virus and Sin Nombre virus are known to cause hantavirus pulmonary syndrome. New World hantavirus infection of immunocompetent hamsters results in an asymptomatic infection except for Andes virus and Maporal virus; the only hantaviruses causing a lethal disease in immunocompetent Syrian hamsters mimicking hantavirus pulmonary syndrome in humans. Hamsters, immunosuppressed with dexamethasone and cyclophosphamide, were infected intramuscularly with different New World hantavirus strains (Bayou virus, Black Creek Canal virus, Caño Delgadito virus, Choclo virus, Laguna Negra virus, and Maporal virus). In the present study, we show that immunosuppression of hamsters followed by infection with a New World hantavirus results in an acute disease that precisely mimics both hantavirus disease in humans and Andes virus infection of hamsters. Infected hamsters showed specific clinical signs of disease and moreover, histological analysis of lung tissue showed signs of pulmonary edema and inflammation within alveolar septa. In this study, we were able to infect immunosuppressed hamsters with different New World hantaviruses reaching a lethal outcome with signs of disease mimicking human disease.

Replication fork reversal triggers fork degradation in BRCA2-defective cells.

PubMed

Mijic, Sofija; Zellweger, Ralph; Chappidi, Nagaraja; Berti, Matteo; Jacobs, Kurt; Mutreja, Karun; Ursich, Sebastian; Ray Chaudhuri, Arnab; Nussenzweig, Andre; Janscak, Pavel; Lopes, Massimo

2017-10-16

Besides its role in homologous recombination, the tumor suppressor BRCA2 protects stalled replication forks from nucleolytic degradation. Defective fork stability contributes to chemotherapeutic sensitivity of BRCA2-defective tumors by yet-elusive mechanisms. Using DNA fiber spreading and direct visualization of replication intermediates, we report that reversed replication forks are entry points for fork degradation in BRCA2-defective cells. Besides MRE11 and PTIP, we show that RAD52 promotes stalled fork degradation and chromosomal breakage in BRCA2-defective cells. Inactivation of these factors restores reversed fork frequency and chromosome integrity in BRCA2-defective cells. Conversely, impairing fork reversal prevents fork degradation, but increases chromosomal breakage, uncoupling fork protection, and chromosome stability. We propose that BRCA2 is dispensable for RAD51-mediated fork reversal, but assembles stable RAD51 nucleofilaments on regressed arms, to protect them from degradation. Our data uncover the physiopathological relevance of fork reversal and illuminate a complex interplay of homologous recombination factors in fork remodeling and stability.BRCA2 is involved in both homologous recombination (HR) and the protection of stalled replication forks from degradation. Here the authors reveal how HR factors cooperate in fork remodeling, showing that BRCA2 supports RAD51 loading on the regressed arms of reversed replication forks to protect them from degradation.

Evaluation of formalin-inactivated Clostridium difficile vaccines administered by parenteral and mucosal routes of immunization in hamsters.

PubMed Central

Torres, J F; Lyerly, D M; Hill, J E; Monath, T P

1995-01-01

Clostridium difficile produces toxins that cause inflammation, necrosis, and fluid in the intestine and is the most important cause of nosocomial antibiotic-associated diarrhea and colitis. We evaluated C. difficile antigens as vaccines to protect against systemic and intestinal disease in a hamster model of clindamycin colitis. Formalin-inactivated culture filtrates from a highly toxigenic strain were administered by mucosal routes (intranasal, intragastric, and rectal) with cholera toxin as a mucosal adjuvant. A preparation of culture filtrate and killed whole cells was also tested rectally. The toxoid was also tested parenterally (subcutaneously and intraperitoneally) and by a combination of three intranasal immunizations followed by a combined intranasal-intraperitoneal boost. Serum antibodies against toxins A and B and whole-cell antigen were measured by enzyme-linked immunosorbent assay, neutralization of cytotoxic activity, and bacterial agglutination. The two rectal immunization regimens induced low antibody responses and protected only 20% of hamsters against death and 0% against diarrhea. The intragastric regimen induced high antibody responses but low protection, 40% against death and 0% against diarrhea. Hamsters immunized by the intranasal, intraperitoneal, and subcutaneous routes were 100% protected against death and partially protected (40, 40, and 20%, respectively) against diarrhea. Among the latter groups, intraperitoneally immunized animals had the highest serum anticytotoxic activity and the highest agglutinating antibody responses. Hamsters immunized intranasally and revaccinated intraperitoneally were 100% protected against both death and diarrhea. Protection against death and diarrhea correlated with antibody responses to all antigens tested. The results indicate that optimal protection against C. difficile disease can be achieved with combined parenteral and mucosal immunization. PMID:7591115

Microinjection of human cell extracts corrects xeroderma pigmentosum defect.

PubMed Central

de Jonge, A J; Vermeulen, W; Klein, B; Hoeijmakers, J H

1983-01-01

Cultured fibroblasts of patients with the DNA repair syndrome xeroderma pigmentosum (XP) were injected with crude cell extracts from various human cells. Injected fibroblasts were then assayed for unscheduled DNA synthesis (UDS) to see whether the injected extract could complement their deficiency in the removal of u.v.-induced thymidine dimers from their DNA. Microinjection of extracts from repair-proficient cells (such as HeLa, placenta) and from cells belonging to XP complementation group C resulted in a temporary correction of the DNA repair defect in XP-A cells but not in cells from complementation groups C, D or F. Extracts prepared from XP-A cells were unable to correct the XP-A repair defect. The UDS of phenotypically corrected XP-A cells is u.v.-specific and can reach the level of normal cells. The XP-A correcting factor was found to be sensitive to the action of proteinase K, suggesting that it is a protein. It is present in normal cells in high amounts, it is stable on storage and can still be detected in the injected cells 8 h after injection. The microinjection assay described in this paper provides a useful tool for the purification of the XP-A (and possibly other) factor(s) involved in DNA repair. Images Fig. 1. PMID:6357782

Foodborne transmission of nipah virus in Syrian hamsters.

PubMed

de Wit, Emmie; Prescott, Joseph; Falzarano, Darryl; Bushmaker, Trenton; Scott, Dana; Feldmann, Heinz; Munster, Vincent J

2014-03-01

Since 2001, outbreaks of Nipah virus have occurred almost every year in Bangladesh with high case-fatality rates. Epidemiological data suggest that in Bangladesh, Nipah virus is transmitted from the natural reservoir, fruit bats, to humans via consumption of date palm sap contaminated by bats, with subsequent human-to-human transmission. To experimentally investigate this epidemiological association between drinking of date palm sap and human cases of Nipah virus infection, we determined the viability of Nipah virus (strain Bangladesh/200401066) in artificial palm sap. At 22°C virus titers remained stable for at least 7 days, thus potentially allowing food-borne transmission. Next, we modeled food-borne Nipah virus infection by supplying Syrian hamsters with artificial palm sap containing Nipah virus. Drinking of 5×10⁸ TCID₅₀ of Nipah virus resulted in neurological disease in 5 out of 8 hamsters, indicating that food-borne transmission of Nipah virus can indeed occur. In comparison, intranasal (i.n.) inoculation with the same dose of Nipah virus resulted in lethal respiratory disease in all animals. In animals infected with Nipah virus via drinking, virus was detected in respiratory tissues rather than in the intestinal tract. Using fluorescently labeled Nipah virus particles, we showed that during drinking, a substantial amount of virus is deposited in the lungs, explaining the replication of Nipah virus in the respiratory tract of these hamsters. Besides the ability of Nipah virus to infect hamsters via the drinking route, Syrian hamsters infected via that route transmitted the virus through direct contact with naïve hamsters in 2 out of 24 transmission pairs. Although these findings do not directly prove that date palm sap contaminated with Nipah virus by bats is the origin of Nipah virus outbreaks in Bangladesh, they provide the first experimental support for this hypothesis. Understanding the Nipah virus transmission cycle is essential for preventing

Foodborne Transmission of Nipah Virus in Syrian Hamsters

PubMed Central

de Wit, Emmie; Prescott, Joseph; Falzarano, Darryl; Bushmaker, Trenton; Scott, Dana; Feldmann, Heinz; Munster, Vincent J.

2014-01-01

Since 2001, outbreaks of Nipah virus have occurred almost every year in Bangladesh with high case-fatality rates. Epidemiological data suggest that in Bangladesh, Nipah virus is transmitted from the natural reservoir, fruit bats, to humans via consumption of date palm sap contaminated by bats, with subsequent human-to-human transmission. To experimentally investigate this epidemiological association between drinking of date palm sap and human cases of Nipah virus infection, we determined the viability of Nipah virus (strain Bangladesh/200401066) in artificial palm sap. At 22°C virus titers remained stable for at least 7 days, thus potentially allowing food-borne transmission. Next, we modeled food-borne Nipah virus infection by supplying Syrian hamsters with artificial palm sap containing Nipah virus. Drinking of 5×108 TCID50 of Nipah virus resulted in neurological disease in 5 out of 8 hamsters, indicating that food-borne transmission of Nipah virus can indeed occur. In comparison, intranasal (i.n.) inoculation with the same dose of Nipah virus resulted in lethal respiratory disease in all animals. In animals infected with Nipah virus via drinking, virus was detected in respiratory tissues rather than in the intestinal tract. Using fluorescently labeled Nipah virus particles, we showed that during drinking, a substantial amount of virus is deposited in the lungs, explaining the replication of Nipah virus in the respiratory tract of these hamsters. Besides the ability of Nipah virus to infect hamsters via the drinking route, Syrian hamsters infected via that route transmitted the virus through direct contact with naïve hamsters in 2 out of 24 transmission pairs. Although these findings do not directly prove that date palm sap contaminated with Nipah virus by bats is the origin of Nipah virus outbreaks in Bangladesh, they provide the first experimental support for this hypothesis. Understanding the Nipah virus transmission cycle is essential for preventing and

Effect of diisopropanolamine upon choline uptake and phospholipid synthesis in Chinese hamster ovary cells.

PubMed

Stott, W T; Kleinert, K M

2008-02-01

Aminoalcohols differ in mammalian toxicity at least in part based upon their ability to alter the metabolism of phospholipids and to cause depletion of the essential nutrient choline in animals. This study examined the incorporation of diisopropanolamine (DIPA) into phospholipids (PLs) and effects of DIPA upon choline uptake and phospholipid synthesis in Chinese hamster ovary (CHO) cells. Results were compared to those of a related secondary alcohol amine, diethanolamine (DEA), whose systemic toxicity is closely associated with its metabolic incorporation into PLs and depletion of choline pools. DIPA caused a dose-related inhibition of (3)H-choline uptake by CHO cells that was approximately 3-4 fold less potent, based upon an IC50, than that reported for DEA. DIPA, in contrast to DEA, did not cause changes in the synthesis rates of (33)P-phosphatidylethanolamine, (33)P-phosphatidylcholine or (33)P-sphingomyelin at either non-toxic or moderately toxic concentrations. Only approximately 0.004%, of administered (14)C-DIPA was metabolically incorporated into PLs, over 30-fold less than the incorporation of (14)C-DEA under similar conditions. Overall, these data and previous pharmacokinetic and toxicity data obtained in vivo suggests that DIPA is distinct from DEA and lacks significant choline and PL metabolism related toxicity in animals.

MSH3 deficiency is not sufficient for a mutator phenotype in Chinese hamster ovary cells.

PubMed

Hinz, J M; Meuth, M

1999-02-01

In the yeast Saccharomyces cerevisiae, the mutS homolog protein products MSH3 and MSH6, each in cooperation with MSH2, play well-defined and specific roles in the repair of DNA mismatches and nucleotide loops. The discrete functions of the human homologs hMSH3 and hMSH6 are less clear and current evidence suggests that the substrate specificity of these proteins may be less strict. To determine the role of MSH3 in mammalian mismatch repair, we employed MSH3-deficient Chinese hamster ovary (CHO) cell lines. No significant changes in mutation rate were detected in the MSH3-deficient strain and there were no differences in sensitivity to DNA-damaging agents. Further analysis of hprt mutants did not show a MSH3-dependent shift in the mutant spectrum. Interestingly, thorough examination of four dinucleotide microsatellite regions revealed instability at only one locus in one of the MSH3-deficient cell lines. These data support the idea of a high degree of redundancy in the function of the MutS homologs MSH3 and MSH6, at least with respect to the control of microsatellite instability.

Radiation damage and defect behavior in proton irradiated lithium-counterdoped n+p silicon solar cells

NASA Technical Reports Server (NTRS)

Stupica, John; Goradia, Chandra; Swartz, Clifford K.; Weinberg, Irving

1987-01-01

Two lithium-counterdoped n+p silicon solar cells with different lithium concentrations were irradiated by 10-MeV protons. Cell performance was measured as a function of fluence, and it was found that the cell with the highest concentration of lithium had the highest radiation resistance. Deep level transient spectroscopy which showed two deep level defects that were lithium related. Relating the defect energy levels obtained from this study with those from earlier work using 1-MeV electron irradiation shows no correlation of the defect energy levels. There is one marked similarity: the absence of the boron-interstitial-oxygen-interstitial defect. This consistency strengthens the belief that lithium interacts with oxygen to prevent the formation of the boron interstitial-oxygen interstitial defect. The results indicate that, in general, addition of lithium in small amounts to the p-base of a boron doped silicon solar cell such that the base remains p-type, tends to increase the radiation resistance of the cell.

Triphenyltin impairs a protein kinase A (PKA)-dependent increase of cytosolic Na{sup +} and Ca{sup 2+} and PKA-independent increase of cytosolic Ca{sup 2+} associated with insulin secretion in hamster pancreatic {beta}-cells

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

Miura, Yoshikazu; Matsui, Hisao

2006-11-01

Oral administration of triphenyltin chloride (TPT) (60 mg/kg body weight) inhibits the insulin secretion by decreasing the cytoplasmic Ca{sup 2+} concentration ([Ca{sup 2+}] {sub i}) induced by glucose-dependent insulinotropic polypeptide (GIP) in pancreatic {beta}-cells of the hamster. To test the possibility that the abnormal level of [Ca{sup 2+}] {sub i} induced by TPT administration could be due to a defect in the cAMP-dependent cytoplasmic Na{sup +} concentration ([Na{sup +}] {sub i}) in the {beta}-cells, we investigated the effects of TPT administration on the changes of [Na{sup +}] {sub i} induced by GIP, glucagon-like peptide-1 (GLP-1), or forskolin, an activator ofmore » adenylyl cyclase, and on the changes of [Na{sup +}] {sub i} or [Ca{sup 2+}] {sub i} induced by 6-Bnz-cAMP, an activator of protein kinase A (PKA), and 8-pCPT-2'-O-Me-cAMP, an activator of Epac. The [Na{sup +}] {sub i} and [Ca{sup 2+}] {sub i} were measured in islet cells loaded with sodium-binding benzofuran isophthalate (SBFI) and fura-2, respectively. In the presence of 135 mM Na{sup +}, TPT administration significantly reduced the rise in [Na{sup +}] {sub i} by 10 nM GLP-1, 10 {mu}M forskolin, and 50 {mu}M 6-Bnz-cAMP, but had not effect in a Na{sup +}-free medium. In the presence of 135 mM Na{sup +}, TPT administration also reduced the rise in [Ca{sup 2+}] {sub i} by 8-pCPT-2'-O-Me-cAMP plus10 {mu}M H-89, a inhibitor of PKA, and 6-Bnz-cAMP. Moreover, TPT administration significantly reduced the insulin secretion by 2 mM db-cAMP, GLP-1, GIP, and 8-pCPT-2'-O-Me-cAMP with and without H-89, and that by 6-Bnz-cAMP and forskolin. Our study suggested that TPT has inhibitory effects on the cellular Ca{sup 2+} response due to a reduced Na{sup +} permeability through PKA-dependent mechanisms in hamster islet cells. Also TPT has the reduction of [Ca{sup 2+}] {sub i} related to Na{sup +}-dependent insulin secretion after an activation of Epac.« less

Numerical study of metal oxide hetero-junction solar cells with defects and interface states

NASA Astrophysics Data System (ADS)

Zhu, Le; Shao, Guosheng; Luo, J. K.

2013-05-01

Further to our previous work on ideal metal oxide (MO) hetero-junction solar cells, a systematic simulation has been carried out to investigate the effects of defects and interface states on the cells. Two structures of the window/absorber (WA) and window/absorber/voltage-enhancer (WAV) were modelled with defect concentration, defect energy level, interface state (ISt) density and ISt energy level as parameters. The simulation showed that the defects in the window layer and the voltage-enhancer layer have very limited effects on the performance of the cells, but those in the absorption layer have profound effects on the cell performance. The interface states at the W/A interface have a limited effect on the performance even for a density up to 1013 cm-2, while those at the A/V interface cause the solar cell to deteriorate severely even at a low density of lower than 1 × 1011 cm-2. It also showed that the back surface field (BSF) induced by band gap off-set in the WAV structure loses its function when defects with a modest concentration exist in the absorption layer and does not improve the open voltage at all.

Senescence of nickel-transformed cells by an X chromosome: Possible epigenetic control

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

Klein, C.B.; Xin Wei Wang; Bhamra, R.K.

1991-02-15

Transfer of a normal Chinese hamster X chromosome (carried in a mouse A9 donor cell line) to a nickel-transformed Chinese hamster cell line with an Xq chromosome deletion resulted in senescense of these previously immortal cells. At early passages of the A9/CX donor cells, the hamster X chromosome was highly active, inducing senescence in 100% of the colonies obtained after its transfer into the nickel-transformed cells. However, senescence was reduced to 50% when Chinese hamster X chromosomes were transferred from later passage A9 cells. Full senescing activity of the intact hamster X chromosome was restored by treatment of the donormore » mouse cells with 5-azacytidine, which induced demethylation of DMA. These results suggest that a senescence gene or genes, which may be located on the Chinese hamster X chromosome, can be regulated by DNA methylation, and that escape from senescence and possibly loss of tumor suppressor gene activity can occur by epigenetic mechanisms.« less

Uninduced adipose-derived stem cells repair the defect of full-thickness hyaline cartilage.

PubMed

Zhang, Hai-Ning; Li, Lei; Leng, Ping; Wang, Ying-Zhen; Lv, Cheng-Yu

2009-04-01

To testify the effect of the stem cells derived from the widely distributed fat tissue on repairing full-thickness hyaline cartilage defects. Adipose-derived stem cells (ADSCs) were derived from adipose tissue and cultured in vitro. Twenty-seven New Zealand white rabbits were divided into three groups randomly. The cultured ADSCs mixed with calcium alginate gel were used to fill the full-thickness hyaline cartilage defects created at the patellafemoral joint, and the defects repaired with gel or without treatment served as control groups. After 4, 8 and 12 weeks, the reconstructed tissue was evaluated macroscopically and microscopically. Histological analysis and qualitative scoring were also performed to detect the outcome. Full thickness hyaline cartilage defects were repaired completely with ADSCs-derived tissue. The result was better in ADSCs group than the control ones. The microstructure of reconstructed tissue with ADSCs was similar to that of hyaline cartilage and contained more cells and regular matrix fibers, being better than other groups. Plenty of collagen fibers around cells could be seen under transmission electron microscopy. Statistical analysis revealed a significant difference in comparison with other groups at each time point (t equal to 4.360, P less than 0.01). These results indicate that stem cells derived from mature adipose without induction possess the ability to repair cartilage defects.

Retinal ganglion cell projections to the hamster suprachiasmatic nucleus, intergeniculate leaflet, and visual midbrain: bifurcation and melanopsin immunoreactivity

NASA Technical Reports Server (NTRS)

Morin, Lawrence P.; Blanchard, Jane H.; Provencio, Ignacio

2003-01-01

The circadian clock in the suprachiasmatic nucleus (SCN) receives direct retinal input via the retinohypothalamic tract (RHT), and the retinal ganglion cells contributing to this projection may be specialized with respect to direct regulation of the circadian clock. However, some ganglion cells forming the RHT bifurcate, sending axon collaterals to the intergeniculate leaflet (IGL) through which light has secondary access to the circadian clock. The present studies provide a more extensive examination of ganglion cell bifurcation and evaluate whether ganglion cells projecting to several subcortical visual nuclei contain melanopsin, a putative ganglion cell photopigment. The results showed that retinal ganglion cells projecting to the SCN send collaterals to the IGL, olivary pretectal nucleus, and superior colliculus, among other places. Melanopsin-immunoreactive (IR) ganglion cells are present in the hamster retina, and some of these cells project to the SCN, IGL, olivary pretectal nucleus, or superior colliculus. Triple-label analysis showed that melanopsin-IR cells bifurcate and project bilaterally to each SCN, but not to the other visual nuclei evaluated. The melanopsin-IR cells have photoreceptive characteristics optimal for circadian rhythm regulation. However, the presence of moderately widespread bifurcation among ganglion cells projecting to the SCN, and projection by melanopsin-IR cells to locations distinct from the SCN and without known rhythm function, suggest that this ganglion cell type is generalized, rather than specialized, with respect to the conveyance of photic information to the brain. Copyright 2003 Wiley-Liss, Inc.

Natural Immunity to Ebola Virus in the Syrian Hamster Requires Antibody Responses.

PubMed

Prescott, Joseph; Falzarano, Darryl; Feldmann, Heinz

2015-10-01

Most ebolaviruses can cause severe disease in humans and other primates, with high case fatality rates during human outbreaks. Although these viruses have been studied for almost 4 decades, little is know regarding the mechanisms by which they cause disease and what is important for protection or treatment after infection. Because of the sporadic nature of the outbreaks and difficulties accessing the populations affected by ebolaviruses, little is also known about what constitutes an appropriate immune response to infection in humans that survive infection. Such knowledge would allow a targeted approach to therapies. In contrast to humans, rodents are protected from disease on infection with ebolaviruses, although adapted versions of some of the viruses are lethal in mice, hamsters and guinea pigs. Using the recently described hamster model, along with T-cell depletion strategies, we show that CD4(+) T cells are required for natural immunity to Ebola virus infection and that CD4-dependent antibody responses are required for immunity in this model. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Nipah virus transmission in a hamster model.

PubMed

de Wit, Emmie; Bushmaker, Trenton; Scott, Dana; Feldmann, Heinz; Munster, Vincent J

2011-12-01

Based on epidemiological data, it is believed that human-to-human transmission plays an important role in Nipah virus outbreaks. No experimental data are currently available on the potential routes of human-to-human transmission of Nipah virus. In a first dose-finding experiment in Syrian hamsters, it was shown that Nipah virus was predominantly shed via the respiratory tract within nasal and oropharyngeal secretions. Although Nipah viral RNA was detected in urogenital and rectal swabs, no infectious virus was recovered from these samples, suggesting no viable virus was shed via these routes. In addition, hamsters inoculated with high doses shed significantly higher amounts of viable Nipah virus particles in comparison with hamsters infected with lower inoculum doses. Using the highest inoculum dose, three potential routes of Nipah virus transmission were investigated in the hamster model: transmission via fomites, transmission via direct contact and transmission via aerosols. It was demonstrated that Nipah virus is transmitted efficiently via direct contact and inefficiently via fomites, but not via aerosols. These findings are in line with epidemiological data which suggest that direct contact with nasal and oropharyngeal secretions of Nipah virus infected individuals resulted in greater risk of Nipah virus infection. The data provide new and much-needed insights into the modes and efficiency of Nipah virus transmission and have important public health implications with regards to the risk assessment and management of future Nipah virus outbreaks.

Nipah Virus Transmission in a Hamster Model

PubMed Central

de Wit, Emmie; Bushmaker, Trenton; Scott, Dana; Feldmann, Heinz; Munster, Vincent J.

2011-01-01

Based on epidemiological data, it is believed that human-to-human transmission plays an important role in Nipah virus outbreaks. No experimental data are currently available on the potential routes of human-to-human transmission of Nipah virus. In a first dose-finding experiment in Syrian hamsters, it was shown that Nipah virus was predominantly shed via the respiratory tract within nasal and oropharyngeal secretions. Although Nipah viral RNA was detected in urogenital and rectal swabs, no infectious virus was recovered from these samples, suggesting no viable virus was shed via these routes. In addition, hamsters inoculated with high doses shed significantly higher amounts of viable Nipah virus particles in comparison with hamsters infected with lower inoculum doses. Using the highest inoculum dose, three potential routes of Nipah virus transmission were investigated in the hamster model: transmission via fomites, transmission via direct contact and transmission via aerosols. It was demonstrated that Nipah virus is transmitted efficiently via direct contact and inefficiently via fomites, but not via aerosols. These findings are in line with epidemiological data which suggest that direct contact with nasal and oropharyngeal secretions of Nipah virus infected individuals resulted in greater risk of Nipah virus infection. The data provide new and much-needed insights into the modes and efficiency of Nipah virus transmission and have important public health implications with regards to the risk assessment and management of future Nipah virus outbreaks. PMID:22180802

Expression of FSH receptor in the hamster ovary during perinatal development

PubMed Central

Chakraborty, Prabuddha; Roy, Shyamal K.

2014-01-01

FSH plays an important role in ovarian follicular development, and it functions via the G-protein coupled FSH receptor. The objectives of the present study were to determine if full-length FSHR mRNA and corresponding protein were expressed in fetal through postnatal hamster ovaries to explain the FSH-induced primordial follicle formation, and if FSH or estrogen (E) would affect the expression. A full-length and two alternately spliced FSHR transcripts were expressed from E14 through P20. The level of the full-length FSHR mRNA increased markedly through P7 before stabilizing at a lower level with the formation and activation of primordial follicles. A predicted 87kDa FSHR protein band was detected in fetal through P4 ovaries, but additional bands appeared as ovary developed. FSHR immunosignal was present in undifferentiated somatic cells and oocytes in early postnatal ovaries, but was granulosa cells specific after follicles formed. Both eCG and E significantly up-regulated full-length FSHR mRNA levels. Therefore, FSHR is expressed in the hamster ovary from the fetal life to account for FSH-induced primordial follicle formation and cAMP production. Further, FSH or E regulates the receptor expression. PMID:25462586

Reproductive responses to photoperiod persist in olfactory bulbectomized Siberian hamsters (Phodopus sungorus).

PubMed

Prendergast, Brian J; Pyter, Leah M; Galang, Jerome; Kay, Leslie M

2009-03-02

In reproductively photoperiodic Syrian hamsters, removal of the olfactory bulbs (OBx) leads to a marked and sustained increase in gonadotrophin secretion which prevents normal testicular regression in short photoperiods. In contrast, among reproductively nonphotoperiodic laboratory strains of rats and mice, bulbectomy unmasks reproductive responses to photoperiod. The role of the olfactory bulbs has been proposed to have opposite effects on responsiveness to photoperiod, depending on the photoperiodicity of the reproductive system; however, Syrian hamsters are the only reproductively photoperiodic rodent species for which the role of the olfactory bulb in reproductive endocrinology has been assessed. This experiment evaluated the role of the olfactory bulbs in the photoperiodic control of reproduction in Siberian hamsters (Phodopus sungorus), an established model species for the study of neural substrates mediating seasonality. Relative to control hamsters housed in long days (15 h light/day), exposure of adult male hamsters to short days (9h light/day) for 8 weeks led to a temporal expansion of the pattern of nocturnal locomotor activity, testicular regression, decreases in testosterone (T) production, and undetectable levels of plasma follicle-stimulating hormone (FSH). Bilateral olfactory bulbectomy failed to affect any of these responses to short days. The patterns of entrainment to long and short days suggests that pre-pineal mechanisms involved in photoperiodic timekeeping are functioning normally in OBx hamsters. The absence of increases in FSH following bulbectomy in long days is incompatible with the hypothesis that the olfactory bulbs provide tonic inhibition of the HPG axis in this species. In marked contrast to Syrian hamsters, the olfactory bulbs of Siberian hamsters play essentially no role in the modulation of tonic gonadotrophin production or gonadotrophin responses to photoperiod.

Use of Adipose Derived Stem Cells to Treat Large Bone Defects. Addendum

DTIC Science & Technology

2009-07-01

optimal delivery . We have also completed characterization of our segmental defect model, including analysis of vascular ingrowth during defect healing...cells seeded in 1.2% Keltone alginate at a density of 12-15x106cells/ml were loaded on 24-well transwell insert membranes [6]. Once hydrogel discs...process from tissue culture plates and hydrogels does not alter the surface phenotype. Gene expression of surface markers and proteins associated with

Thermostability of sperm nuclei assessed by microinjection into hamster oocytes

EPA Science Inventory

Nuclei isolated from spermatozoa of various species (golden hamster, mouse, human, rooster, and the fish tilapia) were heated at 60 degrees-125 degrees C for 20-120 min and then microinjected into hamster oocytes to determine whether they could decondense and develop into pronucl...

Black tea extract and dental caries formation in hamsters.

PubMed

Linke, Harald A B; LeGeros, Racquel Z

2003-01-01

Several studies have suggested that green tea and Oolong tea extracts have antibacterial and anticariogenic properties in vitro and in vivo. The aim of the present study was to determine the effect of a standardized black tea extract (BTE) on caries formation in inbred hamsters on a regular and a cariogenic diet. Eighty hamsters were divided into four groups of 20 animals each. Two groups received a pelleted regular diet (LabChow) with water or BTE ad libitum. The other two groups received a powdered cariogenic diet (Diet 2000, containing 56% sucrose) with water or BTE ad libitum. The animals were kept for 3 months on their respective diets and then were sacrificed. The heads were retained, the jaws were prepared and stained using alizarin mordant red II, and were then scored for dental caries according to the Keyes method. This is the first study indicating that BTE, as compared with water, significantly decreased caries formation by 56.6% in hamsters on a regular diet and by 63.7% in hamsters on a cariogenic diet (P < 0.05). In the cariogenic diet group BTE, reduced the mandibular caries score of the hamsters slightly more than the maxillary caries score. The fluoride content of the standardized BTE solution was frequently monitored during the experiment; the mean fluoride concentration was found to be 4.22 ppm. A frequent intake of black tea can significantly decrease caries formation, even in the presence of sugars in the diet.

The hamster flank organ model: Is it relevant to man

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

Franz, T.J.; Lehman, P.A.; Pochi, P.

1989-10-01

The critical role that androgens play in the etiology of acne has led to a search for topically active antiandrogens and the frequent use of the flank organ of the golden Syrian hamster as an animal model. 17-alpha-propyltestosterone (17-PT) has been identified as having potent antiandrogenic activity in the hamster model, and this report describes its clinical evaluation. Two double-blind placebo controlled studies comparing 4% 17-PT in 80% alcohol versus vehicle alone were conducted. One study examined 17-PT sebosuppressive activity in 20 subjects. The second study examined its efficacy in 44 subjects having mild to moderate acne. A third studymore » measured in vitro percutaneous absorption of 17-PT through hamster flank and monkey skin, and human face skin in-vivo, using radioactive drug. 17-PT was found to be ineffective in reducing either the sebum excretion rate or the number of inflammatory acne lesions. Failure of 17-PT to show clinical activity was not a result of poor percutaneous absorption. Total absorption in man was 7.7% of the dose and only 1.0% in the hamster. The sebaceous gland of hamster flank organ is apparently more sensitive to antiandrogens than the human sebaceous gland.« less

Aryl- and alkyl-phosphorus-containing flame retardants induced mitochondrial impairment and cell death in Chinese hamster ovary (CHO-k1) cells.

PubMed

Huang, Chao; Li, Na; Yuan, Shengwu; Ji, Xiaoya; Ma, Mei; Rao, Kaifeng; Wang, Zijian

2017-11-01

Phosphorus-containing flame retardants (PFRs) are increasingly in demand worldwide as replacements for brominated flame retardants (BFRs), but insufficient available toxicological information on PFRs makes assessing their health risks challenging. Mitochondria are important targets of various environmental pollutants, and mitochondrial dysfunction may lead to many common diseases. In the present study, mitochondria impairment-related endpoints were measured by a high content screening (HCS) assay for 11 selected non-halogen PFRs in Chinese hamster ovary (CHO-k1) cells. A cluster analysis was used to categorize these PFRs into three groups according to their structural characteristics and results from the HCS assay. Two groups, containing long-chain alkyl-PFRs and all aryl-PFRs, were found to cause mitochondrial impairment but showed different mechanisms of toxicity. Due to the high correlation between cell death and mitochondrial impairment, two PFRs with different structures, trihexyl phosphate (THP) and cresyl diphenyl phosphate (CDP), were selected and compared with chlorpyrifos (CPF) to elucidate their mechanism of inducing cell death. THP (an alkyl-PFR) was found to utilize a similar pathway as CPF to induce apoptosis. However, cell death induced by CDP (an aryl-PFR) was different from classical necrosis based on experiments to discriminate among the different modes of cell death. These results confirm that mitochondria might be important targets for some PFRs and that differently structured PFRs could function via distinct mechanisms of toxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identification, Expression, and Physiological Functions of Siberian Hamster Gonadotropin-Inhibitory Hormone

PubMed Central

Ubuka, Takayoshi; Inoue, Kazuhiko; Fukuda, Yujiro; Mizuno, Takanobu; Ukena, Kazuyoshi; Kriegsfeld, Lance J.

2012-01-01

Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that inhibits gonadotropin secretion in birds and mammals. To further understand its physiological roles in mammalian reproduction, we identified its precursor cDNA and endogenous mature peptides in the Siberian hamster brain. The Siberian hamster GnIH precursor cDNA encoded two RFamide-related peptide (RFRP) sequences. SPAPANKVPHSAANLPLRF-NH2 (Siberian hamster RFRP-1) and TLSRVPSLPQRF-NH2 (Siberian hamster RFRP-3) were confirmed as mature endogenous peptides by mass spectrometry from brain samples purified by immunoaffinity chromatography. GnIH mRNA expression was higher in long days (LD) compared with short days (SD). GnIH mRNA was also highly expressed in SD plus pinealectomized animals, whereas expression was suppressed by melatonin, a nocturnal pineal hormone, administration. GnIH-immunoreactive (-ir) neurons were localized to the dorsomedial region of the hypothalamus, and GnIH-ir fibers projected to hypothalamic and limbic structures. The density of GnIH-ir perikarya and fibers were higher in LD and SD plus pinealectomized hamsters than in LD plus melatonin or SD animals. The percentage of GnRH neurons receiving close appositions from GnIH-ir fiber terminals was also higher in LD than SD, and GnIH receptor was expressed in GnRH-ir neurons. Finally, central administration of hamster RFRP-1 or RFRP-3 inhibited LH release 5 and 30 min after administration in LD. In sharp contrast, both peptides stimulated LH release 30 min after administration in SD. These results suggest that GnIH peptides fine tune LH levels via its receptor expressed in GnRH-ir neurons in an opposing fashion across the seasons in Siberian hamsters. PMID:22045661

Slow Replication Fork Velocity of Homologous Recombination-Defective Cells Results from Endogenous Oxidative Stress.

PubMed

Wilhelm, Therese; Ragu, Sandrine; Magdalou, Indiana; Machon, Christelle; Dardillac, Elodie; Técher, Hervé; Guitton, Jérôme; Debatisse, Michelle; Lopez, Bernard S

2016-05-01

Replications forks are routinely hindered by different endogenous stresses. Because homologous recombination plays a pivotal role in the reactivation of arrested replication forks, defects in homologous recombination reveal the initial endogenous stress(es). Homologous recombination-defective cells consistently exhibit a spontaneously reduced replication speed, leading to mitotic extra centrosomes. Here, we identify oxidative stress as a major endogenous source of replication speed deceleration in homologous recombination-defective cells. The treatment of homologous recombination-defective cells with the antioxidant N-acetyl-cysteine or the maintenance of the cells at low O2 levels (3%) rescues both the replication fork speed, as monitored by single-molecule analysis (molecular combing), and the associated mitotic extra centrosome frequency. Reciprocally, the exposure of wild-type cells to H2O2 reduces the replication fork speed and generates mitotic extra centrosomes. Supplying deoxynucleotide precursors to H2O2-exposed cells rescued the replication speed. Remarkably, treatment with N-acetyl-cysteine strongly expanded the nucleotide pool, accounting for the replication speed rescue. Remarkably, homologous recombination-defective cells exhibit a high level of endogenous reactive oxygen species. Consistently, homologous recombination-defective cells accumulate spontaneous γH2AX or XRCC1 foci that are abolished by treatment with N-acetyl-cysteine or maintenance at 3% O2. Finally, oxidative stress stimulated homologous recombination, which is suppressed by supplying deoxynucleotide precursors. Therefore, the cellular redox status strongly impacts genome duplication and transmission. Oxidative stress should generate replication stress through different mechanisms, including DNA damage and nucleotide pool imbalance. These data highlight the intricacy of endogenous replication and oxidative stresses, which are both evoked during tumorigenesis and senescence initiation

Effect of curcumin on pathogenesis of hamster-opisthorchiasis through apoptosis-related gene expression.

PubMed

Sriraj, Pranee; Boonmars, Thidarut; Boonjaraspinyo, Sirintip; Kaewsamut, Butsara; Srisawangwong, Tuanchai; Sithithaworn, Paiboon; Wu, Zhiliang

2009-11-01

The present study investigated the effect of curcumin, a phenolic compound with yellow color from Curcuma longa L., on the expression of the apoptosis-related genes [BAX (Bcl-2 associated protein X), PKB, p53, MDM2 (mouse double minute 2), caspase 9, c-Ski, smad1 and smad4] in hamster opisthorchiasis. On Opisthorchis viverrini infection treated with dietary curcumin apoptosis-related gene expression profiles were similar to O. viverrini-infected group, but the expression levels seemed lower. Light microscopic observation revealed that aggregation of inflammatory cells surrounding the hepatic bile ducts in the groups infected with O. viverrini and treated with dietary curcumin was lower than in infected group. The intensity of the response is correlated with expression of the genes studied. The results suggest that curcumin reduces pathogenesis in hamster-opisthorchiasis by controlling apoptosis-related gene expression.

Defective homing is associated with altered Cdc42 activity in cells from patients with Fanconi anemia group A

PubMed Central

Zhang, Xiaoling; Shang, Xun; Guo, Fukun; Murphy, Kim; Kirby, Michelle; Kelly, Patrick; Reeves, Lilith; Smith, Franklin O.; Williams, David A.

2008-01-01

Previous studies showed that Fanconi anemia (FA) murine stem cells have defective reconstitution after bone marrow (BM) transplantation. The mechanism underlying this defect is not known. Here, we report defective homing of FA patient BM progenitors transplanted into mouse models. Using cells from patients carrying mutations in FA complementation group A (FA-A), we show that when transplanted into nonobese diabetic/severe combined immunodeficiency (NOD/SCID) recipient mice, FA-A BM cells exhibited impaired homing activity. FA-A cells also showed defects in both cell-cell and cell-matrix adhesion. Complementation of FA-A deficiency by reexpression of FANCA readily restored adhesion of FA-A cells. A significant decrease in the activity of the Rho GTPase Cdc42 was found associated with these defective functions in patient-derived cells, and expression of a constitutively active Cdc42 mutant was able to rescue the adhesion defect of FA-A cells. These results provide the first evidence that FA proteins influence human BM progenitor homing and adhesion via the small GTPase Cdc42-regulated signaling pathway. PMID:18565850

FATE OF FLUORIDE-INDUCED SUBAMELOBLASTIC CYSTS IN DEVELOPING HAMSTER MOLAR TOOTH GERMS

PubMed Central

Lyaruu, DM; Alberga, JMR; Kwee, NCH; Bervoets, TJM; Bronckers, ALJJ; DenBesten, PK

2016-01-01

White opacities and pits are developmental defects in enamel caused by high intake of fluoride (F) during amelogenesis. We tested the hypothesis that these enamel pits develop at locations where F induces the formation of sub-ameloblastic cysts. We followed the fate of these cysts during molar development over time. Mandibles from hamster pups injected with 20 mg NaF/kg at postnatal day 4 were excised from 1 h after injection till shortly after tooth eruption, 8 days later. Tissues were histologically processed and cysts located and measured. Cysts were formed at early secretory stage and transitional stage of amelogenesis and detected as early 1 h after injection. The number of cysts increased from 1 to almost 4 per molar during the first 16 h post-injection. The size of the cysts was about the same, i.e., 0.46±0.29 ×106 μm3 at 2hr and 0.50±0.35×106 μm3 at 16 h post-injection. By detachment of the ameloblasts the forming enamel surface below the cyst was cell-free the first 16 h post-injection. With time new ameloblasts repopulated and covered the enamel surface in the cystic area. Three days after injection all cysts had disappeared and the integrity of the ameloblastic layer restored. After eruption, white opaque areas with intact enamel surface were found occlusally at similar anatomical locations as late secretory stage cysts were seen pre-eruptively. We conclude that at this moderate F dose, the opaque sub-surface defects with intact surface enamel (white spots) are the consequence of the fluoride-induced cystic lesions formed earlier under the late secretory–transitional stage ameloblasts. PMID:21277565

Stable expression of recombinant human coagulation factor XIII in protein-free suspension culture of Chinese hamster ovary cells.

PubMed

Chun, B H; Bang, W G; Park, Y K; Woo, S K

2001-11-01

The recombinant a and bsubunits for human coagulation factor XIII were transfected into Chinese hamster ovary (CHO) cells. CHO cells were amplified and selected with methotrexate in adherent cultures containing serum, and CHO 1-62 cells were later selected in protein-free medium. To develop a recombinant factor XIII production process in a suspension culture, we have investigated the growth characteristics of CHO cells and the maintenance of factor XIII expression in the culture medium. Suspension adaptation of CHO cells was performed in protein-free medium, GC-CHO-PI, by two methods, such as serum weaning and direct switching from serum containing media to protein-free media. Although the growth of CHO cells in suspension culture was affected initially by serum depletion, cell specific productivity of factor XIII showed only minor changes by the direct switching to protein-free medium during a suspension culture. As for the long-term stability of factor XIII, CHO 1-62 cells showed a stable expression of factor XIII in protein-free condition for 1000 h. These results indicate that the CHO 1-62cells can be adapted to express recombinant human factor XIII in a stable maimer in suspension culture using a protein-free medium. Our results demonstrate that enhanced cell growth in a continuous manner is achievable for factor XIII production in a protein-free medium when a perfusion bioreactor culture system with a spin filter is employed.

Phosphorylation of 3-deazaguanosine by nicotinamide riboside kinase in Chinese hamster ovary cells.

PubMed

Saunders, P P; Tan, M T; Spindler, C D; Robins, R K

1989-12-01

The growth inhibitory activity of 3-deazaguanosine toward a mutant line (TGR-3) of Chinese hamster ovary cells deficient in hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8) was substantially reversed by the simultaneous addition of nicotinamide riboside. The activities of most other ribonucleoside analogues tested were unaffected. The formation of cellular 3-deazaGMP and 3-deazaGTP from the ribonucleoside analogue, as measured by high-pressure liquid chromatography, was inhibited by the presence of nicotinamide riboside. The inhibition was dependent on concentration of 3-deazaguanosine and could also be demonstrated by following the metabolism of 3-deazaguanosine, labeled with 14C in the ribose moiety, to [14C]3-deazaGTP. In the presence of 100 microM nicotinamide riboside formation of the labeled triphosphate derivative of 3-deazaguanosine was undetectable. A 3-deazaguanosine phosphorylating activity was separated from other cellular kinases by DEAE-cellulose chromatography. Contaminating purine nucleoside phosphorylase (EC 2.4.2.1) was subsequently removed by sucrose density gradient centrifugation. The resulting enzyme preparation demonstrated the greatest activities with nicotinamide riboside and 3-deazaguanosine and, in addition, could also phosphorylate tiazofurin and guanosine to lesser, but significant, degrees. These and other observations suggest that 3-deazaguanosine, and perhaps other agents such as tiazofurin, may, at least in part, be phosphorylated by a nicotinamide ribonucleoside kinase in these cells. If so, it is possible that the activity of this agent in other types of cells in vivo could be dependent upon the presence of this enzyme and that it could be influenced by cellular concentrations of the natural pyridine nucleoside.

The Syrian hamster embryo cells transformation assay identifies efficiently nongenotoxic carcinogens, and can contribute to alternative, integrated testing strategies.

PubMed

Benigni, Romualdo; Bossa, Cecilia; Tcheremenskaia, Olga; Battistelli, Chiara Laura; Giuliani, Alessandro

2015-02-01

The long-term carcinogenesis bioassays have played a central role in protecting human health, but for ethical and practical reasons their use is dramatically diminishing and the genotoxicity short-term tests have taken the pivotal role in the pre-screening of chemical carcinogenicity. However, this strategy cannot detect nongenotoxic carcinogens. Since up to 25% of IARC human carcinogens are recognized to have nongenotoxic mechanisms of action, the risk they pose to human health cannot be disregarded, and it is urgent to fill the gap in the tools for alternative testing. In this paper, we analyze from different perspectives the ability of Cell Transformation Assays to identify nongenotoxic carcinogens, and we conclude that the Syrian hamster embryo cells test is able to identify nongenotoxic carcinogens with 80-90% efficiency, and thus, can play an important role in integrated, alternative testing strategies. Copyright © 2015 Elsevier B.V. All rights reserved.

Cloning and characterization of the hamster and guinea pig nicotinic acid receptors.

PubMed

Torhan, April Smith; Cheewatrakoolpong, Boonlert; Kwee, Lia; Greenfeder, Scott

2007-09-01

In this study, we present the identification and characterization of hamster and guinea pig nicotinic acid receptors. The hamster receptor shares approximately 80-90% identity with the nucleotide and amino acid sequences of human, mouse, and rat receptors. The guinea pig receptor shares 76-80% identity with the nucleotide and amino acid sequences of these other species. [(3)H]nicotinic acid binding affinity at guinea pig and hamster receptors is similar to that in human (dissociation constant = 121 nM for guinea pig, 72 nM for hamster, and 74 nM for human), as are potencies of nicotinic acid analogs in competition binding studies. Inhibition of forskolin-stimulated cAMP production by nicotinic acid and related analogs is also similar to the activity in the human receptor. Analysis of mRNA tissue distribution for the hamster and guinea pig nicotinic acid receptors shows expression across a number of tissues, with higher expression in adipose, lung, skeletal muscle, spleen, testis, and ovary.

Electrophysiological characteristics of hamster dorsal root ganglion cells and their response to axotomy.

PubMed

Gurtu, S; Smith, P A

1988-02-01

1. The active and passive membrane properties of neurons in the lower lumbar (L6, L7) or sacral (S1) dorsal root ganglia from golden hamsters were examined in vitro by means of conventional intracellular recording techniques. Data were collected from neurons exhibiting action potentials (AP) of 70 mV or more in amplitude. 2. Cells with axonal conduction velocities (CV) greater than 20 m/s were termed fast-A-cells, those with CVs between 2.5 and 20 m/s were termed A-delta-cells, and those with CVs less than 1 m/s were termed C-cells. 3. Fast-A-cells usually exhibited short-duration APs (2.51 +/- 0.41 ms, n = 19) followed by short (less than 50 ms) afterhyperpolarizations (AHPs). C-cells usually exhibited long-duration APs (10.5 +/- 0.69 ms, n = 18) followed by long-duration AHPs (much greater than 50 ms). The characteristics of APs in A-delta-cells (AP mean duration 3.34 +/- 0.42 ms, n = 32) were intermediate between those of fast-A- and C-cells. Long AHPs (duration much greater than 50 ms) were manifest in 43.8% of A-delta-cells. 4. A time-dependent sag in hyperpolarizing electrotonic potentials (rectification) was found in 68.8% of fast-A-cells, 45.5% of A-delta-cells, and 62.5% of C-cells. 5. To examine neuronal properties 1-6 wk after transection of the sciatic nerve (axotomy), cells were reclassified as SAP (short action potential) cells and LAP (long action potential) cells. Cells in the SAP category had AP durations less than 5 ms and included all fast-A-cells and the majority of A-delta-cells. The LAP category included cells with AP durations greater than 8 ms contained only C-cells. 6. Axotomy failed to decrease the CV of LAP cells or A-delta-cells in the SAP group. The CV of LAP cells may have increased (P less than 0.05), whereas that of SAP cells was unchanged. 7. The duration of the AP and AHP of SAP cells were slightly increased (0.1 greater than P greater than 0.05), whereas AP and AHP duration of LAP cells were unchanged after axotomy. AHP amplitudes

Hibernation, stress, intestinal functions, and catecholoamine turnover rate in hamsters and gerbils

NASA Technical Reports Server (NTRS)

Musacchia, X. J.

1973-01-01

Bioenergetic studies on hamsters during depressed metabolic states are reported. External support of blood glucose extended the survival times of hibernating animals. Radioresistance increased in hibernating as well as in hypothermic hamsters. Marked changes in hamster catecholamine turnover rates were observed during acclimatization to high temperature stress. High radioresistance levels of the gerbil gastrointestinal system were attributed in part to the ability of the gut to maintain functional integrity.

Photoperiod history differentially impacts reproduction and immune function in adult Siberian hamsters.

PubMed

Prendergast, Brian J; Pyter, Leah M

2009-12-01

Seasonal changes in numerous aspects of mammalian immune function arise as a result of the annual variation in environmental day length (photoperiod), but it is not known if absolute photoperiod or relative change in photoperiod drives these changes. This experiment tested the hypothesis that an individual's history of exposure to day length determines immune responses to ambiguous, intermediate-duration day lengths. Immunological (blood leukocytes, delayed-type hypersensitivity reactions [DTH]), reproductive, and adrenocortical responses were assessed in adult Siberian hamsters (Phodopus sungorus) that had been raised initially in categorically long (15-h light/day; 15L) or short (9L) photoperiods and were subsequently transferred to 1 of 7 cardinal experimental photoperiods between 9L and 15L, inclusive. Initial photoperiod history interacted with contemporary experimental photoperiods to determine reproductive responses: 11L, 12L, and 13L caused gonadal regression in hamsters previously exposed to 15L, but elicited growth in hamsters previously in 9L. In hamsters with a 15L photoperiod history, photoperiods < or = 11L elicited sustained enhancement of DTH responses, whereas in hamsters with a 9L photoperiod history, DTH responses were largely unaffected by increases in day length. Enhancement and suppression of blood leukocyte concentrations occurred at 13L in hamsters with photoperiod histories of 15L and 9L, respectively; however, prior exposure to 9L imparted marked hysteresis effects, which suppressed baseline leukocyte concentrations. Cortisol concentrations were only enhanced in 15L hamsters transferred to 9L and, in common with DTH, were unaffected by photoperiod treatments in hamsters with a 9L photoperiod history. Photoperiod history acquired in adulthood impacts immune responses to photoperiod, but manifests in a markedly dissimilar fashion as compared to the reproductive system. Prior photoperiod exposure has an enduring impact on the ability of the

Acute brown adipose tissue temperature response to cold in monosodium glutamate-treated Siberian hamsters

PubMed Central

Leitner, Claudia; Bartness, Timothy J.

2014-01-01

Neonatal monosodium glutamate (MSG) administration increases adiposity, decreases energy expenditure and is associated with arcuate nucleus (Arc) destruction. Disrupted brown adipose tissue (BAT) thermogenesis underlies some of these effects, although, interscapular BAT temperature (TIBAT) has not been measured. Therefore, we tested the effects of neonatal MSG or vehicle administration in Siberian hamsters and, when they were adults, measured TIBAT during acute cold exposure. The Arc and its projection to the hypothalamic paraventricular nucleus (PVH) are both components of the CNS outflow circuits to IBAT, with the latter implicated in BAT thermogenesis that could be compromised by MSG treatment. Using a viral transneuronal tract tracer, pseudorabies virus (PRV), we also tested whether the components of these circuits were intact. As adults, MSG-treated hamsters had significantly increased body mass and some white fat pad masses, markedly reduced Arc Nissl and neuropeptide staining, and PVH neuropeptide fiber staining. Cold-exposed (18 h at 5 °C) MSG- and vehicle-treated hamsters initially maintained TIBAT, but the ability of the former waned after 2 h being significantly decreased by 18 h. PRV immunoreactive fibers/cells were not altered by neonatal MSG treatment despite substantial Arc and PVH destruction. MSG- and vehicle-treated hamsters given an exogenous norepinephrine challenge showed identical increases in the duration and peak of TIBAT. Thus, the inability of MSG-treated animals to sustain TIBAT in the cold is not due to any obvious MSG-induced deletions of central sympathetic outflow circuits to IBAT, but appears to be extrinsic to the tissue nevertheless. PMID:19643091

Infestivity of Demodex canis to hamster skin engrafted onto SCID mice.

PubMed

Tani, Kenji; Une, Satoshi; Hasegawa, Atsuhiko; Adachi, Makoto; Kanda, Naoko; Watanabe, Shin-ichi; Nakaichi, Munekazu; Taura, Yasuho

2005-04-01

We demonstrated that Demodex canis was transferred to skin xenografts of a dog and a hamster onto severe combined immunodeficiency mice. After the transfer of mites, the number of eggs, larvae, nymphs and adult mites per gram of canine and hamster xenografts increased, whereas no live mites were detected on murine allograft. These results indicate that D. canis proliferates in hair follicles of dog and hamster skins but not in murine allograft. Therefore, D. canis may have host preference but not strict host-specificity.

Electronic properties of deep-level defects in proton irradiated AlGaAs-GaAs solar cells

NASA Technical Reports Server (NTRS)

Li, S. S.

1981-01-01

Deep level transient spectroscopy and capacitance voltage techniques as well as analysis of the forward current voltage (I-V) characteristics and SEM-EIC data were carried out for proton irradiated GaAs solar cells over a wide range of proton energies and proton fluences. Defect and recombination parameters such as defect energy levels and density, carrier capture cross sections and lifetimes as well as diffusion lengths in the undoped n-GaAs LPE layers were determined. Good correlation between these defect parameters and solar cell performance parameters was obtained for GaAs solar cells irradiated by 200 and 290 KeV protons. It was found that 200 to 290 KeV protons will produce the most defects and damages to the GaAs solar cell structure used. The influence of the low temperature (200 to 400 C) periodic thermal annealing on the deep level defects and the performance of the 200 KeV proton irradiated cells is discussed.

Neurons identified by NeuN/Fox-3 immunoreactivity have a novel distribution in the hamster and mouse suprachiasmatic nucleus.

PubMed

Morin, Lawrence P; Hefton, Sara; Studholme, Keith M

2011-11-03

The suprachiasmatic nucleus (SCN) has several structural characteristics and cell phenotypes shared across species. Here, we describe a novel feature of SCN anatomy that is seen in both hamster and mouse. Frozen sections through the SCN were obtained from fixed brains and stained for the presence of immunoreactivity to neuronal nuclear protein (NeuN-IR) using a mouse monoclonal antibody which is known to exclusively identify neurons. NeuN-IR did not identify all SCN neurons as medial NeuN-IR neurons were generally not present. In the hamster, NeuN-IR cells are present rostrally, scattered in the dorsal half of the nucleus. More caudally, the NeuN-IR cells are largely, but not exclusively, scattered inside the lateral and dorsolateral border. At mid- to mid-caudal SCN levels, a dense group of NeuN-IR cells extends from the dorsolateral border ventromedially to encompass the central subnucleus of the SCN (SCNce). The pattern is similar in the mouse SCN. NeuN-IR does not co-localize with either cholecystokinin- or vasoactive intestinal polypeptide, but does with vasopressin-IR in the caudal SCN. In the hamster SCNce, numerous cells contain both calbindin- and NeuN-IR. The distribution of NeuN-IR cells in the SCN is unique, especially with regard to its generally lateral location through the length of the nucleus. The distribution of NeuN-IR cells is not consistent with most schemas representing SCN organization or with terminology referring to its widely accepted subdivisions. NeuN has recently been identified as Fox-3 protein. Its function in the SCN is not known, nor is it known why a large proportion of SCN cells do not contain NeuN-IR. Copyright © 2011 Elsevier B.V. All rights reserved.

Cross-species transcriptomic approach reveals genes in hamster implantation sites.

PubMed

Lei, Wei; Herington, Jennifer; Galindo, Cristi L; Ding, Tianbing; Brown, Naoko; Reese, Jeff; Paria, Bibhash C

2014-12-01

The mouse model has greatly contributed to understanding molecular mechanisms involved in the regulation of progesterone (P4) plus estrogen (E)-dependent blastocyst implantation process. However, little is known about contributory molecular mechanisms of the P4-only-dependent blastocyst implantation process that occurs in species such as hamsters, guineapigs, rabbits, pigs, rhesus monkeys, and perhaps humans. We used the hamster as a model of P4-only-dependent blastocyst implantation and carried out cross-species microarray (CSM) analyses to reveal differentially expressed genes at the blastocyst implantation site (BIS), in order to advance the understanding of molecular mechanisms of implantation. Upregulation of 112 genes and downregulation of 77 genes at the BIS were identified using a mouse microarray platform, while use of the human microarray revealed 62 up- and 38 down-regulated genes at the BIS. Excitingly, a sizable number of genes (30 up- and 11 down-regulated genes) were identified as a shared pool by both CSMs. Real-time RT-PCR and in situ hybridization validated the expression patterns of several up- and down-regulated genes identified by both CSMs at the hamster and mouse BIS to demonstrate the merit of CSM findings across species, in addition to revealing genes specific to hamsters. Functional annotation analysis found that genes involved in the spliceosome, proteasome, and ubiquination pathways are enriched at the hamster BIS, while genes associated with tight junction, SAPK/JNK signaling, and PPARα/RXRα signalings are repressed at the BIS. Overall, this study provides a pool of genes and evidence of their participation in up- and down-regulated cellular functions/pathways at the hamster BIS. © 2014 Society for Reproduction and Fertility.

Pentoxifylline increases sperm penetration into zona-free hamster oocytes without increasing the acrosome reaction.

PubMed

Morales, P; Llanos, M; Yovich, J L; Cummins, J M; Vigil, P

1993-01-01

Several drugs have been used to stimulate human sperm motility, including 3-deoxy-adenosine, caffeine, and pentoxifylline. Pentoxifylline is an inhibitor of the phosphodiesterase and may stimulate sperm motility by increasing the intracellular levels of cAMP. In this study we have evaluated the effect of pentoxifylline in the outcome of the sperm penetration assay into zona-free hamster oocytes. Twenty-seven semen samples, obtained for diagnostic purposes, were used. After the motile sperm were selected by the swim-up technique, the samples were divided into two aliquots. One aliquot was incubated with 1 mg ml-1 of pentoxifylline at 37 degrees C, 5% CO2 for 30 min. The control aliquot was incubated with culture medium. The samples were then washed and resuspended in fresh, pentoxifylline-free medium, at a sperm concentration of 10 x 10(6) cells ml-1. One hundred microlitres of each sperm suspension was then deposited under oil and 30-40 zona-free hamster oocytes were added. After 6 h of gamete coincubation, the percentage of penetrated oocytes and the number of decondensed sperm heads were evaluated. The percentage of acrosome-reacted sperm was evaluated using the Pisum sativum lectin. The percentage of zona-free hamster oocytes penetrated was increased after pentoxifylline-treatment. The percentage of acrosome reacted sperm and the number of decondensed sperm heads per egg were not different between the control and the pentoxifylline-treated groups. The results suggest that the beneficial effect of pentoxifylline upon the sperm cells is not mediated by stimulation of the acrosome reaction.

Altered cytokeratin expression during chemoprevention of experimental hamster buccal pouch carcinogenesis by garlic.

PubMed

Balasenthil, S; Rao, K S; Nagini, S

2002-03-01

Cytokeratins (also known as keratins (K)) are members of the family of intermediate filaments and form major components of the mammalian epithelial cell cytoskeleton. Cytokeratins have emerged as reliable cellular markers of oral cancer development and chemoprevention because of their abundance, stability and high antigenicity. We investigated the effect of aqueous garlic extract on cytokeratin expression during 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis. Hamsters were divided into four groups of six animals. Animals in group 1 were painted with a 0.5% solution of DMBA in liquid paraffin, on the right buccal pouches, three times a week for 14 weeks. Group 2 animals were painted with DMBA as in group 1 and also received 250 mg/kg body weight aqueous garlic extract orally on alternate days to the DMBA application. Group 3 animals received garlic extract only, as in group 2. Group 4 animals received neither DMBA nor garlic extract and served as the control. The hamsters were killed after an experimental period of 14 weeks. Cytokeratin expression was studied using human monoclonal antibodies AE1 and AE3, which react with type I and II keratins. In DMBA-induced squamous cell carcinomas, decreased expression of high molecular weight keratins was observed. Administration of garlic extract to animals painted with DMBA suppressed HBP carcinomas and restored normal cytokeratin expression. The results of the present study suggest that inhibition of HBP carcinogenesis by garlic may be due to its regulatory effects on differentiation, tumour invasiveness, migratory and metastatic potential. We suggest that one of the mechanisms of tumour inhibition by garlic is an influence on cellular differentiation.

Psoriasis associated with idiopathic CD4+ T-cell lymphopenia: a regulatory T-cell defect?

PubMed

Baroudjian, B; Viguier, M; Battistella, M; Beneton, N; Pagès, C; Gener, G; Bégon, E; Bachelez, H

2014-07-01

Idiopathic CD4(+) lymphocytopenia (ICL) is a rare immunodeficiency syndrome of unknown origin for which the increased risks of opportunistic infections and of malignancies have been well established; however, skin dysimmune diseases, including psoriasis, have been scarcely reported up to now. We report herein the severe course of psoriasis in four patients with ICL, and show evidence for a defect in the skin recruitment of regulatory CD4(+) FoxP3(+) T cells. These data raise the apparent paradigm of the occurrence of a severe immunomediated disease together with a profound T-cell defect, a model that might also apply to other immune deficiencies associated with psoriasis. © 2014 British Association of Dermatologists.

Photoperiodic Regulation of the Orexigenic Effects of Ghrelin in Siberian Hamsters

PubMed Central

Bradley, Sean P.; Pattullo, Lucia M.; Patel, Priyesh N.; Prendergast, Brian J.

2010-01-01

Animals living in temperate climates with predictable seasonal changes in food availability may use seasonal information to engage different metabolic strategies. Siberian hamsters decrease costs of thermoregulation during winter by reducing food intake and body mass in response to decreasing or short day lengths (SD). These experiments examined whether SD reductions in food intake in hamsters is driven, at least in part, by altered behavioral responses to ghrelin, a gut-derived orexigenic peptide which induces food intake via NPY-dependent mechanisms. Relative to hamsters housed in long day (LD) photoperiods, SD hamsters consumed less food in response to i.p. treatment with ghrelin across a range of doses from 0.03 to 3 mg/kg. To determine whether changes in photoperiod alter behavioral responses ghrelin-induced activation of NPY neurons, c-Fos and NPY expression were quantified in the arcuate nucleus (ARC) via double-label fluorescent immunocytochemistry following i.p. treatment with 0.3 mg/kg ghrelin or saline. Ghrelin induced c-Fos immunoreactivity (-ir) in a greater proportion of NPY-ir neurons of LD relative to SD hamsters. In addition, following ghrelin treatment, a greater proportion of ARC c-Fos-ir neurons were identifiable as NPY-ir in LD relative to SD hamsters. Changes in day length markedly alter the behavioral response to ghrelin. The data also identify photoperiod-induced changes in the ability of ghrelin to activate ARC NPY neurons as a possible mechanism by which changes in day length alter food intake. PMID:20600050

The induction by X-rays of chromosome aberrations in male guinea-pigs, golden hamsters and rabbits. II. Properties of translocations induced in post-meiotic stages.

PubMed

Cox, B D; Lyon, M F

1975-07-01

Translocations induced by X-rays in post-meiotic germ cells of male guinea-pigs, golden hamsters and rabbits were studied cytologically in the F1 sons of the irradiated males. The percentage of spermatocytes displaying multivalent configurations varied with the translocation, but the average percentage appeared to depend on the species: fewer quadrivalents were observed in hamster than in guinea-pig heterozygotes and most were recorded for rabbit heterozygotes. Chain quadrivalents were more abundant than ring quadrivalents at meiosis for the guinea-pig and hamster, in contrast to the mouse. Too few translocation heterozygotes were examined to determine which meiotic configuration was the more prevalent in the rabbit. In all three species, as in the mouse, translocations were found which caused male sterility, due to partial or complete failure of spermatogenesis, although most translocations caused semi-sterility. For these semi-sterile males both the frequency and time of embryonic death in the progeny appeared to be the same as in the mouse. It is concluded that similar types of chromosome aberrations are induced by X-rays in post-meiotic germ cells of male guinea-pigs, rabbits, golden hamsters and mice.

Modeling of defect-tolerant thin multi-junction solar cells for space application

NASA Astrophysics Data System (ADS)

Mehrotra, A.; Alemu, A.; Freundlich, A.

2012-02-01

Using drift-diffusion model and considering experimental III-V material parameters, AM0 efficiencies of lattice-matched multijunction solar cells have been calculated and the effects of dislocations and radiation damage have been analyzed. Ultrathin multi-junction devices perform better in presence of dislocations or/and radiation harsh environment compared to conventional thick multijunction devices. Our results show that device design optimization of Ga0.51In0.49P/GaAs multijunction devices leads to an improvement in EOL efficiency from 4.8%, for the conventional thick device design, to 12.7%, for the EOL optimized thin devices. In addition, an optimized defect free lattice matched Ga0.51In0.49P/GaAs solar cell under 1016cm-2 1Mev equivalent electron fluence is shown to give an EOL efficiency of 12.7%; while a Ga0.51In0.49P/GaAs solar cell with 108 cm-2 dislocation density under 1016cm-2 electron fluence gives an EOL efficiency of 12.3%. The results suggest that by optimizing the device design, we can obtain nearly the same EOL efficiencies for high dislocation metamorphic solar cells and defect filtered metamorphic multijunction solar cells. The findings relax the need for thick or graded buffer used for defect filtering in metamorphic devices. It is found that device design optimization allows highly dislocated devices to be nearly as efficient as defect free devices for space applications.

Cell division patterns and chromosomal segregation defects in oral cancer stem cells.

PubMed

Kaseb, Hatem O; Lewis, Dale W; Saunders, William S; Gollin, Susanne M

2016-09-01

Oral squamous cell carcinoma (OSCC) is a serious public health problem caused primarily by smoking and alcohol consumption or human papillomavirus. The cancer stem cell (CSC) theory posits that CSCs show unique characteristics, including self-renewal and therapeutic resistance. Examining biomarkers and other features of CSCs is critical to better understanding their biology. To this end, the results show that cellular SOX2 immunostaining correlates with other CSC biomarkers in OSCC cell lines and marks the rare CSC population. To assess whether CSC division patterns are symmetrical, resulting in two CSC, or asymmetrical, leading to one CSC and one cancer cell, cell size and fluorescence intensity of mitotic cells stained with SOX2 were analyzed. Asymmetrical SOX2 distribution in ≈25% of the mitoses analyzed was detected. Chromosomal instability, some of which is caused by chromosome segregation defects (CSDs), is a feature of cancer cells that leads to altered gene copy numbers. We compare chromosomal instability (as measured by CSDs) between CSCs (SOX2+) and non-CSCs (SOX2-) from the same OSCC cell lines. CSDs were more common in non-CSCs (SOX2-) than CSCs (SOX2+) and in symmetrical CSC (SOX2+) mitotic pairs than asymmetrical CSC (SOX2+/SOX2-) mitotic pairs. CSCs showed fewer and different types of CSDs after ionizing radiation treatment than non-CSCs. Overall, these data are the first to demonstrate both symmetrical and asymmetrical cell divisions with CSDs in OSCC CSC. Further, the results suggest that CSCs may undergo altered behavior, including therapeutic resistance as a result of chromosomal instability due to chromosome segregation defects. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Regulation of lipid metabolism by obeticholic acid in hyperlipidemic hamsters.

PubMed

Dong, Bin; Young, Mark; Liu, Xueqing; Singh, Amar Bahadur; Liu, Jingwen

2017-02-01

The farnesoid X receptor (FXR) plays critical roles in plasma cholesterol metabolism, in particular HDL-cholesterol (HDL-C) homeostasis. Obeticholic acid (OCA) is a FXR agonist being developed for treating various chronic liver diseases. Previous studies reported inconsistent effects of OCA on regulating plasma cholesterol levels in different animal models and in different patient populations. The mechanisms underlying its divergent effects have not yet been thoroughly investigated. The scavenger receptor class B type I (SR-BI) is a FXR-modulated gene and the major receptor for HDL-C. We investigated the effects of OCA on hepatic SR-BI expression and correlated such effects with plasma HDL-C levels and hepatic cholesterol efflux in hyperlipidemic hamsters. We demonstrated that OCA induced a time-dependent reduction in serum HDL-C levels after 14 days of treatment, which was accompanied by a significant reduction of liver cholesterol content and increases in fecal cholesterol in OCA-treated hamsters. Importantly, hepatic SR-BI mRNA and protein levels in hamsters were increased to 1.9- and 1.8-fold of control by OCA treatment. Further investigations in normolipidemic hamsters did not reveal OCA-induced changes in serum HDL-C levels or hepatic SR-BI expression. We conclude that OCA reduces plasma HDL-C levels and promotes transhepatic cholesterol efflux in hyperlipidemic hamsters via a mechanism involving upregulation of hepatic SR-BI.

Pulmonary toxicity in hamsters of smoke particles from Kuwaiti oil fires.

PubMed Central

Brain, J D; Long, N C; Wolfthal, S F; Dumyahn, T; Dockery, D W

1998-01-01

The Kuwaiti oil wells set on fire by retreating Iraqi troops at the end of the Persian Gulf War released complex particles, inorganic and organic gases, and hydrocarbons into the atmosphere, damaging the environment where many people live and work. In this study, we assessed the health effects of particles from the Kuwaiti oil fires by instilling hamsters intratracheally with particles (<3.5 microM in size) collected in Ahmadi, a residential area in Kuwait located downwind of hundreds of oil fires. Twenty-four hours after instillation, we performed bronchoalveolar lavage (BAL) to assess various indicators of pulmonary inflammation, including neutrophil and macrophage numbers; albumin, an index of air-blood barrier permeability; and activities of three enzymes: lactate dehydrogenase (LDH; an indicator of cell injury), myeloperoxidase (MPO; which indicates activation of neutrophils), and ss-N-acetylglucosaminidase (GLN; which is indicative of damage to macrophages or neutrophils). We compared the response of hamsters instilled with particles from Ahmadi to animals instilled with urban particles collected in St. Louis, Missouri. We also compared the Ahmadi particles against a highly fibrogenic positive control ([alpha]-quartz) and a relatively nontoxic negative control (iron oxide). When compared to hamsters instilled with particles from St. Louis, the animals treated with the Ahmadi particles had between 1.4- and 2.2-fold more neutrophils in their BAL fluids. The Ahmadi hamsters had more macrophages and lower MPO and LDH activities, but comparable albumin levels and GLN activities. Thus, the acute toxicity of the Ahmadi particles was roughly similar to that of urban particles collected in the United States, when identical masses were compared. However, the relatively higher concentrations of particles measured in Kuwait and Saudi Arabia during the oil fires (at times more than 16 times higher than the EPA standard) is of particular concern. In addition, since the

A biologically based model of growth and senescence of Syrian hamster embryo (SHE) cells after exposure to arsenic.

PubMed Central

Liao, K H; Gustafson, D L; Fox, M H; Chubb, L S; Reardon, K F; Yang, R S

2001-01-01

We modified the two-stage Moolgavkar-Venzon-Knudson (MVK) model for use with Syrian hamster embryo (SHE) cell neoplastic progression. Five phenotypic stages are proposed in this model: Normal cells can either become senescent or mutate into immortal cells followed by anchorage-independent growth and tumorigenic stages. The growth of normal SHE cells was controlled by their division, death, and senescence rates, and all senescent cells were converted from normal cells. In this report, we tested the modeling of cell kinetics of the first two phenotypic stages against experimental data evaluating the effects of arsenic on SHE cells. We assessed cell division and death rates using flow cytometry and correlated cell division rates to the degree of confluence of cell cultures. The mean cell death rate was approximately equal to 1% of the average division rate. Arsenic did not induce immortalization or further mutations of SHE cells at concentrations of 2 microM and below, and chromium (3.6 microM) and lead (100 microM) had similar negative results. However, the growth of SHE cells was inhibited by 5.4 microM arsenic after a 2-day exposure, with cells becoming senescent after only 16 population doublings. In contrast, normal cells and cells exposed to lower arsenic concentrations grew normally for at least 30 population doublings. The biologically based model successfully predicted the growth of normal and arsenic-treated cells, as well as the senescence rates. Mechanisms responsible for inducing cellular senescence in SHE cells exposed to arsenic may help explain the apparent inability of arsenic to induce neoplasia in experimental animals. PMID:11748027

DNA (DEOXYRIBONUCLEIC ACID) SYNTHESIS FOLLOWING MICROINJECTION OF HETEROLOGOUS SPERM AND SOMATIC CELL NUCLEI INTO HAMSTER OOCYTES

EPA Science Inventory

The authors have investigated the ability of the hamster oocyte to initiate DNA synthesis in nuclei differing in basic protein content. DNA synthesis was studied by autoradiography in oocytes that had been incubated in 3H-thymidine after being parthenogenetically activated by sha...

Defective B cell tolerance in adenosine deaminase deficiency is corrected by gene therapy

PubMed Central

Sauer, Aisha V.; Morbach, Henner; Brigida, Immacolata; Ng, Yen-Shing; Aiuti, Alessandro; Meffre, Eric

2012-01-01

Adenosine deaminase (ADA) gene defects are among the most common causes of SCID. Restoration of purine metabolism and immune functions can be achieved by enzyme replacement therapy, or more effectively by bone marrow transplant or HSC gene therapy (HSC-GT). However, autoimmune complications and autoantibody production, including anti-nuclear antibodies (ANAs), frequently occur in ADA-SCID patients after treatment. To assess whether ADA deficiency affects the establishment of B cell tolerance, we tested the reactivity of recombinant antibodies isolated from single B cells of ADA-SCID patients before and after HSC-GT. We found that before HSC-GT, new emigrant/transitional and mature naive B cells from ADA-SCID patients contained more autoreactive and ANA-expressing clones, indicative of defective central and peripheral B cell tolerance checkpoints. We further observed impaired B cell receptor (BCR) and TLR functions in B cells after ADA inhibition, which may underlie the defects in B cell tolerance. Strikingly, after HSC-GT, ADA-SCID patients displayed quasi-normal early B cell tolerance checkpoints, as evidenced by restored removal of developing autoreactive and ANA-expressing B cells. Hence, ADA plays an essential role in controlling autoreactive B cell counterselection by regulating BCR and TLR functions. PMID:22622038

Injectable gellan gum hydrogels with autologous cells for the treatment of rabbit articular cartilage defects.

PubMed

Oliveira, João T; Gardel, Leandro S; Rada, Tommaso; Martins, Luís; Gomes, Manuela E; Reis, Rui L

2010-09-01

In this work, the ability of gellan gum hydrogels coupled with autologous cells to regenerate rabbit full-thickness articular cartilage defects was tested. Five study groups were defined: (a) gellan gum with encapsulated chondrogenic predifferentiated rabbit adipose stem cells (ASC + GF); (b) gellan gum with encapsulated nonchondrogenic predifferentiated rabbit adipose stem cells (ASC); (c) gellan gum with encapsulated rabbit articular chondrocytes (AC) (standard control); (d) gellan gum alone (control); (e) empty defect (control). Full-thickness articular cartilage defects were created and the gellan gum constructs were injected and left for 8 weeks. The macroscopic aspect of the explants showed a progressive increase of similarity with the lateral native cartilage, stable integration at the defect site, more pronouncedly in the cell-loaded constructs. Tissue scoring showed that ASC + GF exhibited the best results regarding tissue quality progression. Alcian blue retrieved similar results with a better outcome for the cell-loaded constructs. Regarding real-time PCR analyses, ASC + GF had the best progression with an upregulation of collagen type II and aggrecan, and a downregulation of collagen type I. Gellan gum hydrogels combined with autologous cells constitute a promising approach for the treatment of articular cartilage defects, and adipose derived cells may constitute a valid alternative to currently used articular chondrocytes. (c) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Arnica Tincture Cures Cutaneous Leishmaniasis in Golden Hamsters.

PubMed

Robledo, Sara M; Vélez, Ivan D; Schmidt, Thomas J

2018-01-12

In search for potential therapeutic alternatives to existing treatments for cutaneous Leishmaniasis, we have investigated the effect of Arnica tincture Ph. Eur. (a 70% hydroethanolic tincture prepared from flowerheads of Arnica montana L.) on the lesions caused by infection with Leishmania braziliensis in a model with golden hamsters. The animals were treated topically with a daily single dose of the preparation for 28 days. Subsequently, the healing process was monitored by recording the lesion size in intervals of 15 days up to day 90. As a result, Arnica tincture fully cured three out of five hamsters while one animal showed an improvement and another one suffered from a relapse. This result was slightly better than that obtained with the positive control, meglumine antimonate, which cured two of five hamsters while the other three showed a relapse after 90 days. This result encourages us to further investigate the potential of Arnica tincture in the treatment of cutaneous Leishmaniasis.

Are Soft Short Tests Good Indicators of Internal Li-ion Cell Defects?

NASA Technical Reports Server (NTRS)

Jeevarajan, J.; Chung, J.-S.; Jung, K.; Park, J.

2013-01-01

The self discharge test at full state of charge, may not be a good one to detect subtle defects since the li-ion chemistry has the highest self discharge at full state of charge. One should characterize self discharge versus storage time for each cell manufacturer/design to differentiate between normal self discharge and that due to a subtle manufacturing defect. The various soft short test methods indicate that if this test is carried out at full discharge (0% SOC) with all capacity removed (by lowering the current load in a stepwise manner to the same end of discharge voltage), then the cells need to be placed in storage for more than 72 hours to get a good analysis on the presence of subtle defects since it takes more than 72 hours to achieve voltage stabilization. If the cells are to be charged up even to a small percentage (ex. 1%), 72 hours are sufficient to determine issues. However, the pass/fail criteria should be based on a valid OCV decline. Less than 10 mV voltage decline is not a good method to detect subtle defects. As mentioned in the first bullet, self discharge is a competing reaction when a charge is introduced and hence a characterization of the self discharge versus storage time is required to fully correlate voltage decline to a failure due to a subtle defect. Soft short test method cannot be relied on for defect detection because cells with and without voltage decline seemed to have similar defects and characteristics. Screening methods such as internal resistance and capacity as well as a 3-sigma range for OCV, mass and dimensions should be used to screen out outliers. A very critical aspect in the understanding of subtle defects is to carry out destructive analysis of cells from every lot to confirm the quality of production and screen all cells and batteries in a stringent manner to have a high quality set of flight cells. Self Discharge Test: Fully charged cells shall be placed in Open circuit stand for 72 hours (OCV measurement twice a

Peripheral gustatory processing of sweet stimuli by golden hamsters.

PubMed

Frank, Marion E; Formaker, Bradley K; Hettinger, Thomas P

2005-07-15

Behaviors and taste-nerve responses to bitter stimuli are linked to compounds that bind T2 receptors expressed in one subset of taste-bud receptor cells (TRCs); and behavioral and neural responses to sweet stimuli are linked to chemical compounds that bind a T1 receptor expressed in a different TRC subset. Neural and behavioral responses to bitter-sweet mixtures, however, complicate the ostensible bitter and sweet labeled lines. In the golden hamster, Mesocricetus auratus, quinine hydrochloride, the bitter prototype, suppresses chorda tympani (CT) nerve responses to the sweet prototype: sucrose. This bitter-sweet inhibition was tested with concentration series of sucrose and dulcin, a hydrophobic synthetic sweetener that hamsters behaviorally cross-generalize with sucrose. Dulcin, sucrose and other sweeteners activate one subset of CT fibers: S neurons; whereas, quinine activates a separate subset of CT fibers: E neurons. Whole-nerve and S-neuron CT responses to a sweetener concentration series, mixed with 0, 1, 3 and 10 mM quinine, were measured for 0-2.5 s transient and/or 2.6-10 s steady-state response periods. Ten-sec total single-fiber records, aligned at response onset, were averaged for 100 ms bins to identify response oscillations. Quinine inhibition of dulcin and sucrose responses was identical. Each log molar increment in quinine resulted in equivalent declines in response to either sweetener. Furthermore, sucrose response decrements paralleled response increments in quinine-sensitive CT neurons to the same quinine increases. A 1.43 Hz bursting rhythm to the sweeteners was unchanged by quinine inhibition or decreases in sweetener concentration. Taste-bud processing, possibly between-cell inhibition and within-cell negative feedback, must modify signals initiated by T1 receptors before they are transmitted to the brain.

Visual Field Defects and Retinal Ganglion Cell Losses in Human Glaucoma Patients

PubMed Central

Harwerth, Ronald S.; Quigley, Harry A.

2007-01-01

Objective The depth of visual field defects are correlated with retinal ganglion cell densities in experimental glaucoma. This study was to determine whether a similar structure-function relationship holds for human glaucoma. Methods The study was based on retinal ganglion cell densities and visual thresholds of patients with documented glaucoma (Kerrigan-Baumrind, et al.) The data were analyzed by a model that predicted ganglion cell densities from standard clinical perimetry, which were then compared to histologic cell counts. Results The model, without free parameters, produced accurate and relatively precise quantification of ganglion cell densities associated with visual field defects. For 437 sets of data, the unity correlation for predicted vs. measured cell densities had a coefficient of determination of 0.39. The mean absolute deviation of the predicted vs. measured values was 2.59 dB, the mean and SD of the distribution of residual errors of prediction was -0.26 ± 3.22 dB. Conclusions Visual field defects by standard clinical perimetry are proportional to neural losses caused by glaucoma. Clinical Relevance The evidence for quantitative structure-function relationships provides a scientific basis of interpreting glaucomatous neuropathy from visual thresholds and supports the application of standard perimetry to establish the stage of the disease. PMID:16769839

9 CFR 3.36 - Primary enclosures used to transport live guinea pigs and hamsters.

Code of Federal Regulations, 2011 CFR

2011-01-01

... live guinea pigs and hamsters. 3.36 Section 3.36 Animals and Animal Products ANIMAL AND PLANT HEALTH..., Care, Treatment, and Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.36 Primary enclosures used to transport live guinea pigs and hamsters. No person subject to the Animal Welfare...

9 CFR 3.36 - Primary enclosures used to transport live guinea pigs and hamsters.

Code of Federal Regulations, 2010 CFR

2010-01-01

... live guinea pigs and hamsters. 3.36 Section 3.36 Animals and Animal Products ANIMAL AND PLANT HEALTH..., Care, Treatment, and Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.36 Primary enclosures used to transport live guinea pigs and hamsters. No person subject to the Animal Welfare...

9 CFR 3.36 - Primary enclosures used to transport live guinea pigs and hamsters.

Code of Federal Regulations, 2014 CFR

2014-01-01

... live guinea pigs and hamsters. 3.36 Section 3.36 Animals and Animal Products ANIMAL AND PLANT HEALTH..., Care, Treatment, and Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.36 Primary enclosures used to transport live guinea pigs and hamsters. No person subject to the Animal Welfare...

9 CFR 3.36 - Primary enclosures used to transport live guinea pigs and hamsters.

Code of Federal Regulations, 2013 CFR

2013-01-01

... live guinea pigs and hamsters. 3.36 Section 3.36 Animals and Animal Products ANIMAL AND PLANT HEALTH..., Care, Treatment, and Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.36 Primary enclosures used to transport live guinea pigs and hamsters. No person subject to the Animal Welfare...

9 CFR 3.36 - Primary enclosures used to transport live guinea pigs and hamsters.

Code of Federal Regulations, 2012 CFR

2012-01-01

... live guinea pigs and hamsters. 3.36 Section 3.36 Animals and Animal Products ANIMAL AND PLANT HEALTH..., Care, Treatment, and Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.36 Primary enclosures used to transport live guinea pigs and hamsters. No person subject to the Animal Welfare...

Seasonal adaptation of dwarf hamsters (Genus Phodopus): differences between species and their geographic origin.

PubMed

Müller, D; Hauer, J; Schöttner, K; Fritzsche, P; Weinert, D

2015-12-01

The genus Phodopus consists of three species--P. campbelli (Pc), P. sungorus (Ps), and P. roborovskii (Pr). They inhabit steppes, semi-deserts, and deserts in continental Asia with a climate changing from a moderate to a hard Continental one with extreme daily and seasonal variations. These different environmental challenges are likely to have consequences for hamsters' morphology, physiology, and behavior. Hamsters of all three species were investigated during the course of the year in the laboratory though using natural lighting and temperature conditions. Motor activity and body temperature were measured continuously, and body mass, testes size, and fur coloration every 1-2 weeks. With regard to the pattern of activity, nearly twice as many Pc as Ps hamsters (25 vs. 14%) failed to respond to changes of photoperiod, whereas all Pr hamsters did. Body mass and testes size were high in summer and low in winter, with the biggest relative change in Ps and the lowest in Pr hamsters. Changes of fur coloration were found in Ps hamsters only. All responding animals (that is excluding Pr), exhibited regular torpor bouts during the short winter days. In autumn, seasonal changes started considerably earlier in Ps hamsters. To investigate the putative causes of these different time courses, a further experiment was performed, to identify the critical photoperiod. Hamsters were kept for 10 weeks under different photoperiods, changing from 16 to 8 h light per day. Motor activity was recorded continuously, to identify responding and non-responding animals. Body mass was measured at the beginning and the end of the experiment, testes mass only at the end. The critical photoperiod was found to be similar in all three species. Though in a further experiment, Pc and Pr hamsters showed a delayed response, whereas the changes in Ps hamsters started immediately following transfer to short-day conditions. The results show that interspecific differences in seasonal adaptation exist, even

Yellow fever 17-D vaccine is neurotropic and produces encephalitis in immunosuppressed hamsters.

PubMed

Mateo, Rosa I; Xiao, Shu-Yuan; Travassos da Rosa, Amelia P A; Lei, Hao; Guzman, Hilda; Lu, Liang; Tesh, Robert B

2007-11-01

Immunosuppressed (cyclophosphamide) adult golden hamsters inoculated intraperitoneally (i.p.) with wild-type Asibi yellow fever virus (YFV) developed a rapidly fatal illness. Histopathologic and immunohistochemical studies of tissues from these animals showed typical hepatic changes of severe yellow fever (inflammation, hepatocyte necrosis, and steatosis) without brain involvement. In contrast, 50% of immunosuppressed hamsters receiving the YFV-17D-attenuated vaccine developed a slowly progressive encephalitic-type illness. Brain tissue from these latter animals revealed focal neuronal changes, inflammation, and YFV antigen-positive neurons; however, the liver and spleen appeared normal. YFV was isolated from brain cultures of many of these animals. Immunocompetent (non-immunosuppressed) hamsters inoculated with both viruses developed a subclinical infection. Results of this study indicate that wild-type YFV is hepatotropic in immunosuppressed hamsters, whereas the attenuated YFV-17 is primarily neurotropic. These findings support current recommendations against yellow fever vaccination of immunosuppressed/immunocompromised people and suggest that this hamster model might be useful for monitoring the safety of other live-attenuated YFV vaccines.

Depopulation of the ventromedial hypothalamic nucleus in the diabetic Chinese hamster.

PubMed

Garris, D R; Diani, A R; Smith, C; Gerritsen, G C

1982-01-01

The relationship between diabetes and the size, density and area of the ventromedial hypothalamic nucleus (VMH) was studied in the genetically diabetic Chinese hamster. Matched diabetic and non-diabetic control chinese hamsters were perfused, the hypothalamus collected, sectioned and stained for light microscopy. The mid-point of each VMH nucleus was located, photographed and enlarged for morphometric analysis. Each neuron that possessed a nucleolus and was located within the confines of a VMH was counted, and subsequently the area of each nucleus and the density of neurons per area of VMH were calculated. The results indicated that both the area and absolute number of neurons within the VMH of diabetic hamsters were significantly reduced compared to control values (P less than 0.01) The density of neurons per unit area of VMH was similar in both groups. These data suggest that the VMH experiences a neuronal depopulation in diabetic hamsters which may have a functional influence on the hypothalamic-pancreatic axis in this species.

The zinc ionophore clioquinol reverses autophagy arrest in chloroquine-treated ARPE-19 cells and in APP/mutant presenilin-1-transfected Chinese hamster ovary cells.

PubMed

Seo, Bo-Ra; Lee, Sook-Jeong; Cho, Kyung Sook; Yoon, Young Hee; Koh, Jae-Young

2015-12-01

Arrested autophagy may contribute to the pathogenesis of Alzheimer's disease. Because we found that chloroquine (CQ) causes arrested autophagy but clioquinol (ClioQ), a zinc ionophore, activates autophagic flux, in the present study, we examined whether ClioQ can overcome arrested autophagy induced by CQ or mutant presenilin-1 (mPS1). CQ induced vacuole formation and cell death in adult retinal pigment epithelial (ARPE-19) cells, but co-treatment with ClioQ attenuated CQ-associated toxicity in a zinc-dependent manner. Increases in lysosome dilation and blockage of autophagic flux by CQ were also markedly attenuated by ClioQ treatment. Interestingly, CQ increased lysosomal pH in amyloid precursor protein (APP)/mPS1-expressing Chinese hamster ovary 7WΔE9 (CHO-7WΔE9) cell line, and ClioQ partially re-acidified lysosomes. Furthermore, accumulation of amyloid-β (Aβ) oligomers in CHO-7WΔE9 cells was markedly attenuated by ClioQ. Moreover, intracellular accumulation of exogenously applied fluorescein isothiocyanate-conjugated Aβ(1-42) was also increased by CQ but was returned to control levels by ClioQ. These results suggest that modulation of lysosomal functions by manipulating lysosomal zinc levels may be a useful strategy for clearing intracellular Aβ oligomers. Copyright © 2015 Elsevier Inc. All rights reserved.

Defective CXCR4 expression in aged bone marrow cells impairs vascular regeneration

PubMed Central

Shao, Hongwei; Xu, Qiyuan; Wu, Qiuling; Ma, Qi; Salgueiro, Luis; Wang, Jian’An; Eton, Darwin; Webster, Keith A; Yu, Hong

2011-01-01

The chemokine stromal cell-derived factor-1 (SDF-1) plays a critical role in mobilizing precursor cells in the bone marrow and is essential for efficient vascular regeneration and repair. We recently reported that calcium augments the expression of chemokine receptor CXCR4 and enhances the angiogenic potential of bone marrow derived cells (BMCs). Neovascularization is impaired by aging therefore we suggested that aging may cause defects of CXCR4 expression and cellular responses to calcium. Indeed we found that both the basal and calcium-induced surface expression of CXCR4 on BMCs was significantly reduced in 25-month-old mice compared with 2-month-old mice. Reduced Ca-induced CXCR4 expression in BMC from aged mice was associated with defective calcium influx. Diminished CXCR4 surface expression in BMC from aged mice correlated with diminished neovascularization in an ischemic hindlimb model with less accumulation of CD34+ progenitor cells in the ischemic muscle with or without local overexpression of SDF-1. Intravenous injection of BMCs from old mice homed less efficiently to ischemic muscle and stimulated significantly less neovascularization compared with the BMCs from young mice. Transplantation of old BMCs into young mice did not reconstitute CXCR4 functions suggesting that the defects were not reversible by changing the environment. We conclude that defects of basal and calcium-regulated functions of the CXCR4/SDF-1 axis in BMCs contribute significantly to the age-related loss of vasculogenic responses. PMID:21143386

Protective effect of enzymatic hydrolysates from highbush blueberry (Vaccinium corymbosum L.) against hydrogen peroxide-induced oxidative damage in Chinese hamster lung fibroblast cell line.

PubMed

Senevirathne, Mahinda; Kim, Soo-Hyun; Jeon, You-Jin

2010-06-01

Blueberry was enzymatically hydrolyzed using selected commercial food grade carbohydrases (AMG, Celluclast, Termamyl, Ultraflo and Viscozyme) and proteases (Alcalase, Flavourzyme, Kojizyme, Neutrase and Protamex) to obtain water soluble compounds, and their protective effect was investigated against H(2)O(2)-induced damage in Chinese hamster lung fibroblast cell line (V79-4) via various published methods. Both AMG and Alcalase hydrolysates showed higher total phenolic content as well as higher cell viability and ROS scavenging activities, and hence, selected for further antioxidant assays. Both AMG and Alcalase hydrolysates also showed higher protective effects against lipid peroxidation, DNA damage and apoptotic body formation in a dose-dependent fashion. Thus, the results indicated that water soluble compounds obtained by enzymatic hydrolysis of blueberry possess good antioxidant activity against H(2)O(2)-induced cell damage in vitro.

Model-directed engineering of "difficult-to-express" monoclonal antibody production by Chinese hamster ovary cells.

PubMed

Pybus, Leon P; Dean, Greg; West, Nathan R; Smith, Andrew; Daramola, Olalekan; Field, Ray; Wilkinson, Stephen J; James, David C

2014-02-01

Despite improvements in volumetric titer for monoclonal antibody (MAb) production processes using Chinese hamster ovary (CHO) cells, some "difficult-to-express" (DTE) MAbs inexplicably reach much lower process titers. These DTE MAbs require intensive cell line and process development activity, rendering them more costly or even unsuitable to manufacture. To rapidly and rationally identify an optimal strategy to improve production of DTE MAbs, we have developed an engineering design platform combining high-yielding transient production, empirical modeling of MAb synthesis incorporating an unfolded protein response (UPR) regulatory loop with directed expression and cell engineering approaches. Utilizing a panel of eight IgG1 λ MAbs varying >4-fold in volumetric titer, we showed that MAb-specific limitations on folding and assembly rate functioned to induce a proportionate UPR in host CHO cells with a corresponding reduction in cell growth rate. Derived from comparative empirical modeling of cellular constraints on the production of each MAb we employed two strategies to increase production of DTE MAbs designed to avoid UPR induction through an improvement in the rate/cellular capacity for MAb folding and assembly reactions. Firstly, we altered the transfected LC:HC gene ratio and secondly, we co-expressed a variety of molecular chaperones, foldases or UPR transactivators (BiP, CypB, PDI, and active forms of ATF6 and XBP1) with recombinant MAbs. DTE MAb production was significantly improved by both strategies, although the mode of action was dependent upon the approach employed. Increased LC:HC ratio or CypB co-expression improved cell growth with no effect on qP. In contrast, BiP, ATF6c and XBP1s co-expression increased qP and reduced cell growth. This study demonstrates that expression-engineering strategies to improve production of DTE proteins in mammalian cells should be product specific, and based on rapid predictive tools to assess the relative impact of

Cytokinesis defect in BY-2 cells caused by ATP-competitive kinase inhibitors.

PubMed

Kozgunova, Elena; Higashiyama, Tetsuya; Kurihara, Daisuke

2016-10-02

Cytokinesis is last but not least in cell division as it completes the formation of the two cells. The main role in cell plate orientation and expansion have been assigned to microtubules and kinesin proteins. However, recently we reported severe cytokinesis defect in BY-2 cells not accompanied by changes in microtubules dynamics. Here we also confirmed that distribution of kinesin NACK1 is not the cause of cytokinesis defect. We further explored inhibition of the cell plate expansion by ATP-competitive inhibitors. Two different inhibitors, 5-Iodotubercidin and ML-7 resulted in a very similar phenotype, which indicates that they target same protein cascade. Interestingly, in our previous study we showed that 5-Iodotubercidin treatment affects concentration of actin filaments on the cell plate, while ML-7 is inhibitor of myosin light chain kinase. Although not directly, it indicates importance of actomyosin complex in plant cytokinesis.

A noise model for the evaluation of defect states in solar cells

PubMed Central

Landi, G.; Barone, C.; Mauro, C.; Neitzert, H. C.; Pagano, S.

2016-01-01

A theoretical model, combining trapping/detrapping and recombination mechanisms, is formulated to explain the origin of random current fluctuations in silicon-based solar cells. In this framework, the comparison between dark and photo-induced noise allows the determination of important electronic parameters of the defect states. A detailed analysis of the electric noise, at different temperatures and for different illumination levels, is reported for crystalline silicon-based solar cells, in the pristine form and after artificial degradation with high energy protons. The evolution of the dominating defect properties is studied through noise spectroscopy. PMID:27412097

Cell-printing and transfer technology applications for bone defects in mice.

PubMed

Tsugawa, Junichi; Komaki, Motohiro; Yoshida, Tomoko; Nakahama, Ken-ichi; Amagasa, Teruo; Morita, Ikuo

2011-10-01

Bone regeneration therapy based on the delivery of osteogenic factors and/or cells has received a lot of attention in recent years since the discovery of pluripotent stem cells. We reported previously that the implantation of capillary networks engineered ex vivo by the use of cell-printing technology could improve blood perfusion. Here, we developed a new substrate prepared by coating glass with polyethylene glycol (PEG) to create a non-adhesive surface and subsequent photo-lithography to finely tune the adhesive property for efficient cell transfer. We examined the cell-transfer efficiency onto amniotic membrane and bone regenerative efficiency in murine calvarial bone defect. Cell transfer of KUSA-A1 cells (murine osteoblasts) to amniotic membrane was performed for 1 h using the substrates. Cell transfer using the substrate facilitated cell engraftment onto the amniotic membrane compared to that by direct cell inoculation. KUSA-A1 cells transferred onto the amniotic membrane were applied to critical-sized calvarial bone defects in mice. Micro-computed tomography (micro-CT) analysis showed rapid and effective bone formation by the cell-equipped amniotic membrane. These results indicate that the cell-printing and transfer technology used to create the cell-equipped amniotic membrane was beneficial for the cell delivery system. Our findings support the development of a biologically stable and effective bone regeneration therapy. Copyright © 2011 John Wiley & Sons, Ltd.

Individual differences in circadian waveform of Siberian hamsters under multiple lighting conditions

PubMed Central

Evans, Jennifer A.; Elliott, Jeffrey A.; Gorman, Michael R.

2013-01-01

Because the circadian clock in the mammalian brain derives from a network of interacting cellular oscillators, characterizing the nature and bases of circadian coupling is fundamental to understanding how the pacemaker operates. Various phenomena involving plasticity in circadian waveform have been theorized to reflect changes in oscillator coupling; however, it remains unclear whether these different behavioral paradigms reference a unitary underlying process. To test if disparate coupling assays index a common mechanism, we examined whether there is co-variation among behavioral responses to various lighting conditions that produce changes in circadian waveform. Siberian hamsters, Phodopus sungorus, were transferred from long to short photoperiods to distinguish short photoperiod responders (SP-R) from non-responders (SP-NR). Short photoperiod chronotyped hamsters were subsequently transferred, along with unselected controls, to 24 h light:dark:light:dark cycles (LDLD) with dim nighttime illumination, a procedure that induces bifurcated entrainment. Under LDLD, SP-R hamsters were more likely to bifurcate their rhythms than SP-NR hamsters or unselected controls. After transfer from LDLD to constant dim light, SP-R hamsters were also more likely to become arrhythmic compared to SP-NR hamsters and unselected controls. In contrast, short photoperiod chronotype did not influence more transient changes in circadian waveform. The present data reveal a clear relationship in the plasticity of circadian waveform across three distinct lighting conditions, suggesting a common mechanism wherein individual differences reflect variation in circadian coupling. PMID:23010663

Pineal-Induced Depression of Free Thyroxine in Syrian Hamsters

DTIC Science & Technology

1985-01-01

activation by blind- ness in Syrian hamsters, can influence free 14 concentration. MATERIALS AND METHODS Male golden hamsters, Mesocricetus auratus...considered that the changes in T4 passively result from pineal- induced hypogonadism and the possible resultant effects on T4 serum bind- ing proteins...the presence of pineal-induced hypogonadism and that, like T4 and FT41, -• ’. 328 Vaughan and Pruitt TESrE S PROSTATE 0.6 80- 20 gn Mgm ,... =_ 9 Mg_

Topical chlorophyll-pheophytin derivative-mediated photodynamic therapy for DMBA-induced hamster buccal pouch premaligant lesions: an in vivo study

NASA Astrophysics Data System (ADS)

Hsu, Yih-Chih; Chiang, Chung-Pin; Chen, Jian Wen; Lee, Jeng-Woei; How, Mon-Hsin

2010-02-01

In Taiwan, oral cancer has become a prominent cancer because of its highest annual increase rate among all cancer diseases. Betel quid chewing habit is a major risk factor for oral precancerous and cancerous lesions and there are more than two million people who have this habit in Taiwan. Our previous studies showed that chlorophyll-pheophytin derivative (CPD)-mediated PDT is very effective for killing of SCC-4 cell lines in vitro. In order to decrease the systemic phototoxic effect of CPD, this study was designed to use a topical CPD-mediated PDT for treatment of DMBA-induced hamster buccal pouch precancerous lesions. DMBA was applied to one of the buccal pouches of hamsters thrice a week for 8 to 10 weeks. Precancerous lesions of moderate to severe dysplasia were induced and proven by histological examination. These induced precancerous lesions were used for testing the efficacy of topical CPD-mediated PDT. Before PDT, fluorescence spectroscopy was used to determine when CPD reached its peak level in the lesional epithelial cells after topical application of CPD gel. We found that CPD reached its peak level in precancerous lesions about 1 hour (range, 0 to 30 hours) after topical application of CPD gel. The precancerous lesions in hamsters were then treated with topical CPD-mediated PDT (fluence rate: 200 mW/cm2; light exposure dose 100 J/cm2) using the portable WonderLight LED 635 nm fiber-guided light device once or twice a week. Visual and histological examination demonstrated that topical CPD-mediated PDT was partially effective treatment modality for DMBA-induced hamster buccal pouch precancerous lesions.

A Syrian golden hamster model recapitulating ebola hemorrhagic fever.

PubMed

Ebihara, Hideki; Zivcec, Marko; Gardner, Donald; Falzarano, Darryl; LaCasse, Rachel; Rosenke, Rebecca; Long, Dan; Haddock, Elaine; Fischer, Elizabeth; Kawaoka, Yoshihiro; Feldmann, Heinz

2013-01-15

Ebola hemorrhagic fever (EHF) is a severe viral infection for which no effective treatment or vaccine is currently available. While the nonhuman primate (NHP) model is used for final evaluation of experimental vaccines and therapeutic efficacy, rodent models have been widely used in ebolavirus research because of their convenience. However, the validity of rodent models has been questioned given their low predictive value for efficacy testing of vaccines and therapeutics, a result of the inconsistent manifestation of coagulopathy seen in EHF. Here, we describe a lethal Syrian hamster model of EHF using mouse-adapted Ebola virus. Infected hamsters displayed most clinical hallmarks of EHF, including severe coagulopathy and uncontrolled host immune responses. Thus, the hamster seems to be superior to the existing rodent models, offering a better tool for understanding the critical processes in pathogenesis and providing a new model for evaluating prophylactic and postexposure interventions prior to testing in NHPs.

Transplantation of dedifferentiated fat cell-derived micromass pellets contributed to cartilage repair in the rat osteochondral defect model.

PubMed

Shimizu, Manabu; Matsumoto, Taro; Kikuta, Shinsuke; Ohtaki, Munenori; Kano, Koichiro; Taniguchi, Hiroaki; Saito, Shu; Nagaoka, Masahiro; Tokuhashi, Yasuaki

2018-03-20

Mature adipocyte-derived dedifferentiated fat (DFAT) cells possesses the ability to proliferate effectively and the potential to differentiate into multiple linages of mesenchymal tissue; similar to adipose-derived stem cells (ASCs). The purpose of this study is to examine the effects of DFAT cell transplantation on cartilage repair in a rat model of osteochondral defects. Full-thickness osteochondral defects were created in the knees of Sprague-Dawley rats bilaterally. Cartilage-like micromass pellets were prepared from green fluorescent protein (GFP)-labeled rat DFAT cells and subsequently transplanted into the affected right knee of these rats. Defects in the left knee were used as a control. Macroscopic and microscopic changes of treated and control defects were evaluated up to 12 weeks post-treatment with DFAT cells. To observe the transplanted cells, sectioned femurs were immunostained for GFP and type II collagen. DFAT cells formed micromass pellets expressing characteristics of immature cartilage in vitro. In the DFAT cell-transplanted limbs, the defects were completely filled with white micromass pellets as early as 2 weeks post-treatment. These limbs became smooth at 4 weeks. Conversely, the defects in the control limbs were still not repaired by 4 weeks. Macroscopic ICRS scores at 2 and 4 weeks were significantly higher in the DFAT cells-transplanted limbs compared to those of the control limbs. The modified O'Driscol histological scores for the DFAT cell-transplanted limbs were significantly higher than those of the control limbs at corresponding time points. GFP-positive DAFT cells were detected in the transplanted area at 2 weeks but hardly visible at 12 weeks post-operation. Transplantation of DFAT cell-derived micromass pellets contribute to cartilage repair in a rat osteochondral defect model. DFAT cell transplantation may be a viable therapeutic strategy for the repair of osteochondral injuries. Copyright © 2018 The Authors. Published by

Regulation of lipid metabolism by obeticholic acid in hyperlipidemic hamsters[S

PubMed Central

Dong, Bin; Young, Mark; Liu, Xueqing; Singh, Amar Bahadur; Liu, Jingwen

2017-01-01

The farnesoid X receptor (FXR) plays critical roles in plasma cholesterol metabolism, in particular HDL-cholesterol (HDL-C) homeostasis. Obeticholic acid (OCA) is a FXR agonist being developed for treating various chronic liver diseases. Previous studies reported inconsistent effects of OCA on regulating plasma cholesterol levels in different animal models and in different patient populations. The mechanisms underlying its divergent effects have not yet been thoroughly investigated. The scavenger receptor class B type I (SR-BI) is a FXR-modulated gene and the major receptor for HDL-C. We investigated the effects of OCA on hepatic SR-BI expression and correlated such effects with plasma HDL-C levels and hepatic cholesterol efflux in hyperlipidemic hamsters. We demonstrated that OCA induced a time-dependent reduction in serum HDL-C levels after 14 days of treatment, which was accompanied by a significant reduction of liver cholesterol content and increases in fecal cholesterol in OCA-treated hamsters. Importantly, hepatic SR-BI mRNA and protein levels in hamsters were increased to 1.9- and 1.8-fold of control by OCA treatment. Further investigations in normolipidemic hamsters did not reveal OCA-induced changes in serum HDL-C levels or hepatic SR-BI expression. We conclude that OCA reduces plasma HDL-C levels and promotes transhepatic cholesterol efflux in hyperlipidemic hamsters via a mechanism involving upregulation of hepatic SR-BI. PMID:27940481

Combination therapies in adjuvant with topical ALA-mediated photodynamic therapy for DMBA-induced hamster buccal pouch premalignant lesions

NASA Astrophysics Data System (ADS)

Yang, Deng-Fu; Hsu, Yih-Chih

2012-03-01

In Taiwan, oral cancer has becomes the fastest growth male cancer disease due to the betel nut chewing habit combing with smoking and alcohol-drinking lifestyle of people. In order to eliminate the systemic phototoxic effect of 5-aminolevulinic acid (ALA), this study was designed to use a topical ALA-mediated PDT for treatment of DMBA-induced hamster buccal pouch precancerous lesions. DMBA was applied to one of the buccal pouches of hamsters thrice a week for 10 to 12 weeks. Cancerous lesions were induced and proven by histological examination. These DMBA-induced cancerous lesions were used for testing the efficacy of topical ALA-mediated PDT. Before PDT, fluorescence spectroscopy was used to determine when ALA reached its peak level in the lesional epithelial cells after topical application of ALA gel. We found that ALA reached its peak level in precancerous lesions about 2.5 hrs after topical application of ALA gel. The cancerous lesions in hamsters were then treated with topical ALA -mediated PDT with light exposure dose of 150 J/cm2 using LED 635 nm fiber-guided light device. Visual examination demonstrated that adjuvant topical ALA -mediated PDT group has shown better therapeutic results in compared to those of non-adjuvant topical ALA-mediated PDT group for DMBA-induced hamster buccal pouch precancerous lesions.

Dopamine mediates testosterone-induced social reward in male Syrian hamsters.

PubMed

Bell, Margaret R; Sisk, Cheryl L

2013-03-01

Adolescent maturation of responses to social stimuli is essential for adult-typical sociosexual behavior. Naturally occurring developmental changes in male Syrian hamster responses to a salient social cue, female hamster vaginal secretions (VS), provide a good model system for investigating neuroendocrine mechanisms of adolescent change in social reward. Sexually naïve adult, but not juvenile, males show a conditioned place preference (CPP) to VS, indicating that VS is not rewarding before puberty. In this series of experiments, the authors examined the roles of testosterone and dopamine receptor activation in mediating the adolescent gain in positive valence of VS. Experiment 1 showed that testosterone replacement is necessary for gonadectomized adult hamsters to form a CPP to VS. Experiment 2 showed that testosterone treatment is sufficient for juvenile hamsters to form a CPP to VS, and that the dopamine receptor antagonist haloperidol blocks formation of a CPP to VS in these animals. Experiments 3 and 4 demonstrated that the disruption of VS CPP with low doses of haloperidol is the result of a reduction in the attractive properties of VS and not attributable to aversive properties of haloperidol. Together, these studies demonstrate that the unconditioned rewarding properties of a social cue necessary for successful adult sociosexual interactions come about as the result of the pubertal increase in circulating testosterone in male hamsters. Furthermore, this social reward can be prevented by dopamine receptor antagonism, indicating that hypothalamic and/or mesocorticolimbic dopaminergic circuits are targets for hormonal activation of social reward.

NREL Develops High-Speed Scanner to Monitor Fuel Cell Material Defects

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

2015-09-01

This highlight describes results of recent work in which polymer electrolyte membrane fuel cell electrodes with intentionally introduced known defects were imaged and analyzed using a fuel cell scanner recently developed at NREL. The highlight is being developed for the September 2015 Alliance S&T Board meeting.

Syrian Hamster as an Animal Model for the Study of Human Influenza Virus Infection.

PubMed

Iwatsuki-Horimoto, Kiyoko; Nakajima, Noriko; Ichiko, Yurie; Sakai-Tagawa, Yuko; Noda, Takeshi; Hasegawa, Hideki; Kawaoka, Yoshihiro

2018-02-15

Ferrets and mice are frequently used as animal models for influenza research. However, ferrets are demanding in terms of housing space and handling, whereas mice are not naturally susceptible to infection with human influenza A or B viruses. Therefore, prior adaptation of human viruses is required for their use in mice. In addition, there are no mouse-adapted variants of the recent H3N2 viruses, because these viruses do not replicate well in mice. In this study, we investigated the susceptibility of Syrian hamsters to influenza viruses with a view to using the hamster model as an alternative to the mouse model. We found that hamsters are sensitive to influenza viruses, including the recent H3N2 viruses, without adaptation. Although the hamsters did not show weight loss or clinical signs of H3N2 virus infection, we observed pathogenic effects in the respiratory tracts of the infected animals. All of the H3N2 viruses tested replicated in the respiratory organs of the hamsters, and some of them were detected in the nasal washes of infected animals. Moreover, a 2009 pandemic (pdm09) virus and a seasonal H1N1 virus, as well as one of the two H3N2 viruses, but not a type B virus, were transmissible by the airborne route in these hamsters. Hamsters thus have the potential to be a small-animal model for the study of influenza virus infection, including studies of the pathogenicity of H3N2 viruses and other strains, as well as for use in H1N1 virus transmission studies. IMPORTANCE We found that Syrian hamsters are susceptible to human influenza viruses, including the recent H3N2 viruses, without adaptation. We also found that a pdm09 virus and a seasonal H1N1 virus, as well as one of the H3N2 viruses, but not a type B virus tested, are transmitted by the airborne route in these hamsters. Syrian hamsters thus have the potential to be used as a small-animal model for the study of human influenza viruses. Copyright © 2018 American Society for Microbiology.

Proteomics analysis identified peroxiredoxin 2 involved in early-phase left ventricular impairment in hamsters with cardiomyopathy.

PubMed

Kuzuya, Kentaro; Ichihara, Sahoko; Suzuki, Yuka; Inoue, Chisa; Ichihara, Gaku; Kurimoto, Syota; Oikawa, Shinji

2018-01-01

Given the hypothesis that inflammation plays a critical role in the progression of cardiovascular diseases, the aim of the present study was to identify new diagnostic and prognostic biomarkers of myocardial proteins involved in early-phase cardiac impairment, using proteomics analysis. Using the two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) combined with MALDI-TOF/TOF tandem mass spectrometry, we compared differences in the expression of proteins in the whole left ventricles between control hamsters, dilated cardiomyopathic hamsters (TO-2), and hypertrophy cardiomyopathic hamsters (Bio14.6) at 6 weeks of age (n = 6, each group). Proteomic analysis identified 10 protein spots with significant alterations, with 7 up-regulated and 3 down-regulated proteins in the left ventricles of both TO-2 and Bio 14.6 hamsters, compared with control hamsters. Of the total alterations, peroxiredoxin 2 (PRDX2) showed significant upregulation in the left ventricles of TO-2 and Bio 14.6 hamsters. Our data suggest that PRDX2, a redox regulating molecule, is involved in early-phase left ventricular impairment in hamsters with cardiomyopathy.

Defective bone repair in mast cell-deficient Cpa3Cre/+ mice.

PubMed

Ramirez-GarciaLuna, Jose Luis; Chan, Daniel; Samberg, Robert; Abou-Rjeili, Mira; Wong, Timothy H; Li, Ailian; Feyerabend, Thorsten B; Rodewald, Hans-Reimer; Henderson, Janet E; Martineau, Paul A

2017-01-01

In the adult skeleton, cells of the immune system interact with those of the skeleton during all phases of bone repair to influence the outcome. Mast cells are immune cells best known for their pathologic role in allergy, and may be involved in chronic inflammatory and fibrotic disorders. Potential roles for mast cells in tissue homeostasis, vascularization and repair remain enigmatic. Previous studies in combined mast cell- and Kit-deficient KitW-sh/W-sh mice (KitW-sh) implicated mast cells in bone repair but KitW-sh mice suffer from additional Kit-dependent hematopoietic and non- hematopoietic deficiencies that could have confounded the outcome. The goal of the current study was to compare bone repair in normal wild type (WT) and Cpa3Cre/+ mice, which lack mast cells in the absence of any other hematopoietic or non- hematopoietic deficiencies. Repair of a femoral window defect was characterized using micro CT imaging and histological analyses from the early inflammatory phase, through soft and hard callus formation, and finally the remodeling phase. The data indicate 1) mast cells appear in healing bone of WT mice but not Cpa3Cre/+ mice, beginning 14 days after surgery; 2) re-vascularization of repair tissue and deposition of mineralized bone was delayed and dis-organised in Cpa3Cre/+ mice compared with WT mice; 3) the defects in Cpa3Cre/+ mice were associated with little change in anabolic activity and biphasic alterations in osteoclast and macrophage activity. The outcome at 56 days postoperative was complete bridging of the defect in most WT mice and fibrous mal-union in most Cpa3Cre/+ mice. The results indicate that mast cells promote bone healing, possibly by recruiting vascular endothelial cells during the inflammatory phase and coordinating anabolic and catabolic activity during tissue remodeling. Taken together the data indicate that mast cells have a positive impact on bone repair.

Defective bone repair in mast cell-deficient Cpa3Cre/+ mice

PubMed Central

Chan, Daniel; Samberg, Robert; Abou-Rjeili, Mira; Wong, Timothy H.; Li, Ailian; Feyerabend, Thorsten B.; Rodewald, Hans-Reimer; Henderson, Janet E.; Martineau, Paul A.

2017-01-01

In the adult skeleton, cells of the immune system interact with those of the skeleton during all phases of bone repair to influence the outcome. Mast cells are immune cells best known for their pathologic role in allergy, and may be involved in chronic inflammatory and fibrotic disorders. Potential roles for mast cells in tissue homeostasis, vascularization and repair remain enigmatic. Previous studies in combined mast cell- and Kit-deficient KitW-sh/W-sh mice (KitW-sh) implicated mast cells in bone repair but KitW-sh mice suffer from additional Kit-dependent hematopoietic and non- hematopoietic deficiencies that could have confounded the outcome. The goal of the current study was to compare bone repair in normal wild type (WT) and Cpa3Cre/+ mice, which lack mast cells in the absence of any other hematopoietic or non- hematopoietic deficiencies. Repair of a femoral window defect was characterized using micro CT imaging and histological analyses from the early inflammatory phase, through soft and hard callus formation, and finally the remodeling phase. The data indicate 1) mast cells appear in healing bone of WT mice but not Cpa3Cre/+ mice, beginning 14 days after surgery; 2) re-vascularization of repair tissue and deposition of mineralized bone was delayed and dis-organised in Cpa3Cre/+ mice compared with WT mice; 3) the defects in Cpa3Cre/+ mice were associated with little change in anabolic activity and biphasic alterations in osteoclast and macrophage activity. The outcome at 56 days postoperative was complete bridging of the defect in most WT mice and fibrous mal-union in most Cpa3Cre/+ mice. The results indicate that mast cells promote bone healing, possibly by recruiting vascular endothelial cells during the inflammatory phase and coordinating anabolic and catabolic activity during tissue remodeling. Taken together the data indicate that mast cells have a positive impact on bone repair. PMID:28350850

Histochemical study of brown-fat cells in the golden hamster (Mesocricetus auratus) in cultures

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

Sokolov, V.E.; Boyadzhieva-Mikhailova, A.; Koncheva, L.

1985-11-01

The authors undertake the task of studying the synthesis of certain hormones by brown-fat cells. The authors used brown-fat cells from the golden hamster. The metabolism of brown-fat cells was studied on precultured cells, which made it possible to detect the synthesis of the studied substances rather than their accumulation in the organ. The authors conducted three experiments. First, fragments of brown fat were cultivated in diffusion chambers in vivo. Pieces of brown fat were cultivated in parallel in vitro on agar (organotypic cultures) and on plasma (histotypic cultures). During cultivation in diffusion chambers, the chambers were implanted in themore » abdominal cavity of young white rats. For in vitro cultivation, TCM 199 plus 15-20% calf serum was used. A total of 36 cultures with 12 cultures in each series of experiments were performed. The auto-radiographic studies of brown-fat cells were conducted on 24-hour cultures and on brown-fat fragments taken from the intact animal. The cultures were incubated with isotopes for 1 h. Either (/sup 3/H)lysine (87.3 Ci/mM specific activity), (/sup 3/H)arginine (16.7 Ci/mM), (/sup 3/H)glycerol (43 Ci/mM), or (/sup 3/H)cholesterol (43 Ci/mM) were added to the medium. After incubation, the cultures were washed three times in pure medium, fixed in Sierra fluid, and embedded in paraffin. The paraffin sections were covered with Ilford K/sub 2/ emulsion, and the preparations were exposed for 20 days at 4/sup 0/C temperature. Radio-immunological methods were used to study the accumulation of estradiol-17-beta in the culture medium by the Dobson method and that of testerone. The culture medium was taken on cultivation days 2,4,6,8, and 10. The medium was changed during cultivation every third day, which made it possible to judge the rates of accumulation of material with increase in the cultivation times.« less

Independent regulation of periarteriolar and perivenular nitric oxide mechanisms in the in vivo hamster cheek pouch microvasculature

PubMed Central

Kim, David D.; Kanetaka, Takehito; Durán, Ricardo G.; Sánchez, Fabiola A.; Bohlen, H Glenn; Durán, Walter N.

2011-01-01

Objective We tested the hypothesis that differential stimulation of nitric oxide (NO) production can be induced in pre- and postcapillary segments of the microcirculation in the hamster cheek pouch. Methods We applied acetylcholine (ACh) or platelet-activating factor (PAF) topically and measured perivascular NO concentration ([NO]) with NO-sensitive microelectrodes in arterioles and venules of the hamster cheek pouch. We also measured NO in cultured coronary endothelial cells (CVEC) after ACh or PAF. Results ACh increased periarteriolar [NO] significantly in a dose-dependent manner. ACh at 1 μM increased [NO] from 438.1±43.4 nM at baseline to 647.9±66.3 nM, while 10 μM ACh increased [NO] from baseline to 1035.0±59.2 nM (P < 0.05). Neither 1 μM nor 10 μM ACh changed perivenular [NO] in the hamster cheek pouch. PAF, at 100 nM, increased perivenular [NO] from 326.6±50.8 nM to 622.8±41.5 nM. Importantly, 100 nM PAF did not increase periarteriolar [NO]. PAF increased [NO] from 3.6 ± 2.1 to 455.5 ± 19.9 in CVEC, while ACh had no effect. Conclusions We conclude that NO production can be stimulated in a differential manner in preand postcapillary segments in the hamster cheek pouch. ACh selectively stimulates the production of NO only in arterioles, while PAF stimulates the production of NO only in venules. PMID:19235626

Improved defect analysis of Gallium Arsenide solar cells using image enhancement

NASA Technical Reports Server (NTRS)

Kilmer, Louis C.; Honsberg, Christiana; Barnett, Allen M.; Phillips, James E.

1989-01-01

A new technique has been developed to capture, digitize, and enhance the image of light emission from a forward biased direct bandgap solar cell. Since the forward biased light emission from a direct bandgap solar cell has been shown to display both qualitative and quantitative information about the solar cell's performance and its defects, signal processing techniques can be applied to the light emission images to identify and analyze shunt diodes. Shunt diodes are of particular importance because they have been found to be the type of defect which is likely to cause failure in a GaAs solar cell. The presence of a shunt diode can be detected from the light emission by using a photodetector to measure the quantity of light emitted at various current densities. However, to analyze how the shunt diodes affect the quality of the solar cell the pattern of the light emission must be studied. With the use of image enhancement routines, the light emission can be studied at low light emission levels where shunt diode effects are dominant.

Ultrastructure of the filiform papillae on the tongue of the hamster.

PubMed Central

Fernandez, B; Suarez, I; Zapata, A

1978-01-01

The fine structure of the filiform papillae on the hamster tongue is described level by level from the basal layer to the surface. We did not observe two distinct types of cells with different morphology or components which could be held responsible for the production of two different types of keratin as have been described in other animals, but rather a uniformity of cell structures in each layer and only the so-called "smooth" type of keratin. However, keratin granules were more abundant in the anterior part of the papilla. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 PMID:689988

[6]-Shogaol, a Novel Chemopreventor in 7,12-Dimethylbenz[a]anthracene-induced Hamster Buccal Pouch Carcinogenesis.

PubMed

Kathiresan, Suresh; Govindhan, Annamalai

2016-04-01

Oral cancer is a major cause of morbidity and mortality in developing countries. Despite advances in chemotherapy for the cancer management, the survival rate has not yet been improved. Dietary nutrient has been receiving a lot of attention and interest in the chemotherapeutic development. [6]-Shogaol is a major bioactive compound identified in ginger that possesses many pharmacological properties. The aim of the present study is to investigate the effect of [6]-shogaol on 7,12-dimethylbenz[a]anthracene-induced hamster buccal pouch (HBP) carcinogenesis. Oral squamous cell carcinoma induced in HBP by painting with 0.5% 7,12-dimethylbenz(a)anthracene (DMBA), thrice in a week for 16 weeks. We observed 100% tumour incidence, decreased levels of lipid peroxidation, antioxidant, and phase II detoxification enzymes (GST, GR and GSH) in DMBA-induced hamsters. Further, enhanced activity of phase I enzymes (cytochrome p450 and b5) and over-expression of mutant p53, Bcl-2 and decreased expression of wild type p53 and Bax were noticed in DMBA-induced hamsters. Our results indicated that [6]-shogaol (10, 20 and 40 mg/kg body weight) treated with DMBA-painted hamsters, considerably reversed tumour incidence, improved antioxidant status, phase II detoxification enzymes, and also inhibit lipid peroxidation and phase I enzymes. Moreover, [6]-shogaol inhibits mutant p53 and Bcl-2 expression and significantly restored normal p53, Bax levels. Thus, we concluded that [6]-shogaol prevents DMBA-induced HBP carcinogenesis through its antioxidant as well as modulating apoptotic signals. Copyright © 2016 John Wiley & Sons, Ltd.

Selective retension of active cells employing low centrifugal force at the medium change during suspension culture of Chinese hamster ovary cells producing tPA.

PubMed

Takagi, M; Ilias, M; Yoshida, T

2000-01-01

The effect of centrifugal force applied for cell separation at the medium change on the growth, metabolism and tissue plasminogen activator (tPA) productivity of Chinese hamster ovary (CHO) cells suspension culture was investigated. The viability of the precipitated cells increased exponentially as the centrifugal force decreased. However, the cell recovery was lower than 91% when centrifugal forces applied for 5 min was less than 67 x g. In cultures incubated for 474 h with 7 medium changes employing centrifugal forces ranging from 67 to 364 x g, a centrifugal force lower than 119 x g resulted in higher specific rates of growth, glucose consumption, and lactate and tPA production during the whole culture period. On the other hand, daily centrifugation at 67 to 537 x g without discarding the supernatant had no effect on the specific rates. The cultures inoculated with cells precipitated at a centrifugal force of 67 x g showed apparently higher specific rates of metabolism compared to those inoculated with cells in the supernatant. The cells in the supernatant and the precipitate obtained following centrifugation at 67 x g have average diameters of 15.5 and 17.4 microm, respectively. The intracellular contents of amino acids, especially nonessential amino acids, of the precipitated cells were markedly higher than those of the cells in the supernatant. These results indicate that large cells with high amino acid content and metabolic activity were selectively retained in the culture by means of centrifugation at low forces such as 67 x g. Consequently, application of a low centrifugal force is recommended for medium change in order to maintain higher specific productivity of suspended mammalian cells in perfusion culture.

A Syrian Golden Hamster Model Recapitulating Ebola Hemorrhagic Fever

PubMed Central

Ebihara, Hideki; Zivcec, Marko; Gardner, Donald; Falzarano, Darryl; LaCasse, Rachel; Rosenke, Rebecca; Long, Dan; Haddock, Elaine; Fischer, Elizabeth; Kawaoka, Yoshihiro; Feldmann, Heinz

2013-01-01

Ebola hemorrhagic fever (EHF) is a severe viral infection for which no effective treatment or vaccine is currently available. While the nonhuman primate (NHP) model is used for final evaluation of experimental vaccines and therapeutic efficacy, rodent models have been widely used in ebolavirus research because of their convenience. However, the validity of rodent models has been questioned given their low predictive value for efficacy testing of vaccines and therapeutics, a result of the inconsistent manifestation of coagulopathy seen in EHF. Here, we describe a lethal Syrian hamster model of EHF using mouse-adapted Ebola virus. Infected hamsters displayed most clinical hallmarks of EHF, including severe coagulopathy and uncontrolled host immune responses. Thus, the hamster seems to be superior to the existing rodent models, offering a better tool for understanding the critical processes in pathogenesis and providing a new model for evaluating prophylactic and postexposure interventions prior to testing in NHPs. PMID:23045629

Dura Mater Stimulates Human Adipose-Derived Stromal Cells to Undergo Bone Formation in Mouse Calvarial Defects

PubMed Central

Levi, Benjamin; Nelson, Emily R.; Li, Shuli; James, Aaron W.; Hyun, Jeong S.; Montoro, Daniel T.; Lee, Min; Glotzbach, Jason P.; Commons, George W.; Longaker, Michael T.

2015-01-01

Human adipose-derived stromal cells (hASCs) have a proven capacity to aid in osseous repair of calvarial defects. However, the bone defect microenvironment necessary for osseous healing is not fully understood. In this study, we postulated that the cell-cell interaction between engrafted ASCs and host dura mater (DM) cells is critical for the healing of calvarial defects. hASCs were engrafted into critical sized calvarial mouse defects. The DM-hASC interaction was manipulated surgically by DM removal or by insertion of a semipermeable or nonpermeable membrane between DM and hASCs. Radiographic, histologic, and gene expression analyses were performed. Next, the hASC-DM interaction is assessed by conditioned media (CM) and coculture assays. Finally, bone morphogenetic protein (BMP) signaling from DM was investigated in vivo using novel BMP-2 and anti-BMP-2/4 slow releasing scaffolds. With intact DM, osseous healing occurs both from host DM and engrafted hASCs. Interference with the DM-hASC interaction dramatically reduced calvarial healing with abrogated BMP-2–Smad-1/5 signaling. Using CM and coculture assays, mouse DM cells stimulated hASC osteogenesis via BMP signaling. Through in vivo manipulation of the BMP-2 pathway, we found that BMP-2 plays an important role in DM stimulation of hASC osteogenesis in the context of calvarial bone healing. BMP-2 supplementation to a defect with disrupted DM allowed for bone formation in a nonhealing defect. DM is an osteogenic cell type that both participates in and stimulates osseous healing in a hASC-engrafted calvarial defect. Furthermore, DM-derived BMP-2 paracrine stimulation appears to play a key role for hASC mediated repair. PMID:21656608

Reconstruction of Ligament and Tendon Defects Using Cell Technologies.

PubMed

Chailakhyan, R K; Shekhter, A B; Ivannikov, S V; Tel'pukhov, V I; Suslin, D S; Gerasimov, Yu V; Tonenkov, A M; Grosheva, A G; Panyushkin, P V; Moskvina, I L; Vorob'eva, N N; Bagratashvili, V N

2017-02-01

We studied the possibility of restoring the integrity of the Achilles tendon in rabbits using autologous multipotent stromal cells. Collagen or gelatin sponges populated with cells were placed in a resorbable Vicryl mesh tube and this tissue-engineered construct was introduced into a defect of the middle part of the Achilles tendon. In 4 months, histological analysis showed complete regeneration of the tendon with the formation of parallel collagen fibers, spindle-shaped tenocytes, and newly formed vessels.

Defects and Interfaces on PtPb Nanoplates Boost Fuel Cell Electrocatalysis.

PubMed

Sun, Yingjun; Liang, Yanxia; Luo, Mingchuan; Lv, Fan; Qin, Yingnan; Wang, Lei; Xu, Chuan; Fu, Engang; Guo, Shaojun

2018-01-01

Nanostructured Pt is the most efficient single-metal catalyst for fuel cell technology. Great efforts have been devoted to optimizing the Pt-based alloy nanocrystals with desired structure, composition, and shape for boosting the electrocatalytic activity. However, these well-known controls still show the limited ability in maximizing the Pt utilization efficiency for achieving more efficient fuel cell catalysis. Herein, a new strategy for maximizing the fuel cell catalysis by controlling/tuning the defects and interfaces of PtPb nanoplates using ion irradiation technique is reported. The defects and interfaces on PtPb nanoplates, controlled by the fluence of incident C + ions, make them exhibit the volcano-like electrocatalytic activity for methanol oxidation reaction (MOR), ethanol oxidation reaction (EOR), and oxygen reduction reaction (ORR) as a function of ion irradiation fluence. The optimized PtPb nanoplates with the mixed structure of dislocations, subgrain boundaries, and small amorphous domains are the most active for MOR, EOR, and ORR. They can also maintain high catalytic stability in acid solution. This work highlights the impact and significance of inducing/controlling the defects and interfaces on Pt-based nanocrystals toward maximizing the catalytic performance by advanced ion irradiation strategy. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Protective effect of enzymatic hydrolysates from highbush blueberry (Vaccinium corymbosum L.) against hydrogen peroxide-induced oxidative damage in Chinese hamster lung fibroblast cell line

PubMed Central

Senevirathne, Mahinda; Kim, Soo-Hyun

2010-01-01

Blueberry was enzymatically hydrolyzed using selected commercial food grade carbohydrases (AMG, Celluclast, Termamyl, Ultraflo and Viscozyme) and proteases (Alcalase, Flavourzyme, Kojizyme, Neutrase and Protamex) to obtain water soluble compounds, and their protective effect was investigated against H2O2-induced damage in Chinese hamster lung fibroblast cell line (V79-4) via various published methods. Both AMG and Alcalase hydrolysates showed higher total phenolic content as well as higher cell viability and ROS scavenging activities, and hence, selected for further antioxidant assays. Both AMG and Alcalase hydrolysates also showed higher protective effects against lipid peroxidation, DNA damage and apoptotic body formation in a dose-dependent fashion. Thus, the results indicated that water soluble compounds obtained by enzymatic hydrolysis of blueberry possess good antioxidant activity against H2O2-induced cell damage in vitro. PMID:20607062

[Purification of arsenic-binding proteins in hamster plasma after oral administration of arsenite].

PubMed

Wang, Wenwen; Zhang, Min; Li, Chunhui; Qin, Yingjie; Hua, Naranmandura

2013-01-01

To purify the arsenic-binding proteins (As-BP) in hamster plasma after a single oral administration of arsenite (iAs(III)). Arsenite was given to hamsters in a single dose. Three types of HPLC columns, size exclusion, gel filtration and anion exchange columns, combined with an inductively coupled argon plasma mass spectrometer (ICP MS) were used to purify the As-BP in hamster plasma. SDS-PAGE was used to confirm the arsenic-binding proteins at each purification step. The three-step purification process successfully separated As-BP from other proteins (ie, arsenic unbound proteins) in hamster plasma. The molecular mass of purified As-BP in plasma was approximately 40-50 kD on SDS-PAGE. The three-step purification method is a simple and fast approach to purify the As-BP in plasma samples.

Variation of expression defects in cell surface 190-kDa protein antigen of Streptococcus mutans.

PubMed

Lapirattanakul, Jinthana; Nomura, Ryota; Matsumoto-Nakano, Michiyo; Srisatjaluk, Ratchapin; Ooshima, Takashi; Nakano, Kazuhiko

2015-05-01

Streptococcus mutans, which consists of four serotypes, c, e, f, and k, possesses a 190-kDa cell surface protein antigen (PA) for initial tooth adhesion. We used Western blot analysis to determine PA expression in 750 S. mutans isolates from 150 subjects and found a significantly higher prevalence of the isolates with PA expression defects in serotypes f and k compared to serotypes c and e. Moreover, the defect patterns could be classified into three types; no PA expression on whole bacterial cells and in their supernatant samples (Type N1), PA expression mainly seen in supernatant samples (Type N2), and only low expression of PA in the samples of whole bacterial cells (Type W). The underlying reasons for the defects were mutations in the gene encoding PA as well as in the transcriptional processing of this gene for Type N1, defects in the sortase gene for Type N2, and low mRNA expression of PA for Type W. Since cellular hydrophobicity and phagocytosis susceptibility of the PA-defective isolates were significantly lower than those of the normal expression isolates, the potential implication of such defective isolates in systemic diseases involving bacteremia other than dental caries was suggested. Additionally, multilocus sequence typing was utilized to characterize S. mutans clones that represented a proportion of isolates with PA defects of 65-100%. Therefore, we described the molecular basis for variation defects in PA expression of S. mutans. Furthermore, we also emphasized the strong association between PA expression defects and serotypes f and k as well as the clonal relationships among these isolates. Copyright © 2015 Elsevier GmbH. All rights reserved.

Openings between Defective Endothelial Cells Explain Tumor Vessel Leakiness

PubMed Central

Hashizume, Hiroya; Baluk, Peter; Morikawa, Shunichi; McLean, John W.; Thurston, Gavin; Roberge, Sylvie; Jain, Rakesh K.; McDonald, Donald M.

2000-01-01

Leakiness of blood vessels in tumors may contribute to disease progression and is key to certain forms of cancer therapy, but the structural basis of the leakiness is unclear. We sought to determine whether endothelial gaps or transcellular holes, similar to those found in leaky vessels in inflammation, could explain the leakiness of tumor vessels. Blood vessels in MCa-IV mouse mammary carcinomas, which are known to be unusually leaky (functional pore size 1.2–2 μm), were compared to vessels in three less leaky tumors and normal mammary glands. Vessels were identified by their binding of intravascularly injected fluorescent cationic liposomes and Lycopersicon esculentum lectin and by CD31 (PECAM) immunoreactivity. The luminal surface of vessels in all four tumors had a defective endothelial monolayer as revealed by scanning electron microscopy. In MCa-IV tumors, 14% of the vessel surface was lined by poorly connected, overlapping cells. The most superficial lining cells, like endothelial cells, had CD31 immunoreactivity and fenestrae with diaphragms, but they had a branched phenotype with cytoplasmic projections as long as 50 μm. Some branched cells were separated by intercellular openings (mean diameter 1.7 μm; range, 0.3–4.7 μm). Transcellular holes (mean diameter 0.6 μm) were also present but were only 8% as numerous as intercellular openings. Some CD31-positive cells protruded into the vessel lumen; others sprouted into perivascular tumor tissue. Tumors in RIP-Tag2 mice had, in addition, tumor cell-lined lakes of extravasated erythrocytes. We conclude that some tumor vessels have a defective cellular lining composed of disorganized, loosely connected, branched, overlapping or sprouting endothelial cells. Openings between these cells contribute to tumor vessel leakiness and may permit access of macromolecular therapeutic agents to tumor cells. PMID:10751361

Role of photoperiod and melatonin in seasonal acclimatization of the djungarian hamster, Phodopus sungorus

NASA Astrophysics Data System (ADS)

Steinlechner, S.; Heldmaier, G.

1982-12-01

The Djungarian hamster, Phodopus sungorus, shows a clear annual cycle in some thermogenic parameters such as nonshivering thermogenesis (NST) and cold resistance. These seasonal changes were found to be basically controlled by natural changes in photoperiod. Further support for this view was obtained by exposing the hamsters to artificial long and short photoperiods. Implantation of melatonin during fall and winter results in an increased thermogenic capacity in both short and long day hamsters comparable to that shown by values of control hamsters exposed to short photoperiods during winter. This thermotropic action of melatonin and of short photoperiod could be found only in fall and winter whereas during spring and summer, melatonin, like photoperiod, had no influence on thermogenic capacities. These results show that the actions of melatonin and photoperiod vary with the season and that they depend upon the photoperiodic history of the hamsters. Our results further indicate that the pineal gland with its hormone melatonin is involved in mediation of photoperiodic control of seasonal acclimatization.

Sweet taste transduction in hamster: sweeteners and cyclic nucleotides depolarize taste cells by reducing a K+ current.

PubMed

Cummings, T A; Daniels, C; Kinnamon, S C

1996-03-01

1. The gigaseal voltage-clamp technique was used to record responses of hamster taste receptor cells to synthetic sweeteners and cyclic nucleotides. Voltage-dependent currents and steady-state currents were monitored during bath exchanges of saccharin, two high-potency sweeteners, 8-chlorophenylthio-adenosine 3',5'-cyclic monophosphate (8cpt-cAMP), and dibutyryl-guanosine 3',5'-cyclic monophosphate (db-cGMP). 2. Of the 237 fungiform taste cells studied, only one in eight was sweet responsive. Outward currents, both voltage-dependent and resting, were reduced by all of the sweeteners tested in sweet-responsive taste cells, whereas these currents were unaffected by sweeteners in sweet-unresponsive taste cells. 3. In every sweet-responsive cell tested, 8cpt-cAMP and db-cGMP mimicked the response to the sweeteners, but neither nucleotide elicited responses in sweet-unresponsive cells. Thus there was a one-to-one correlation between sweet responsivity and cyclic nucleotide responsivity. 4. Sweet responses showed cross adaptation with cyclic nucleotide responses. This indicates that the same ion channel is modulated by sweeteners and cyclic nucleotides. 5. The sweetener- and cyclic nucleotide-blocked current had an apparent reversal potential of -50 mV, which was close to the potassium reversal potential in these experiments. In addition, there was no effect of sweeteners and cyclic nucleotides in the presence of the K+ channel blocker tetraethylammonium bromide (TEA). These data suggest that block of a resting, TEA-sensitive K+ current is the final common step leading to taste cell depolarization during sweet transduction. 6. These data, together with data from a previous study (Cummings et al. 1993), suggest that both synthetic sweeteners and sucrose utilize second-messenger pathways that block a resting K+ conductance to depolarize the taste cell membrane.

Photodynamic therapy of hamster Greene melanoma in vitro and in vivo using bacteriochlorin-a as photosensitizer

NASA Astrophysics Data System (ADS)

Schuitmaker, J. J.; Van Best, Jaap A.; van Delft, J. L.; Jannink, J. E.; Oosterhuis, J. A.; Vrensen, Gijs F.; Ms Wolff-Rouendaal, Didi; Dubbelman, T. M.

1996-01-01

Efficient photodynamic therapy (PDT) of malignant melanoma may be possible with photosensitizers having absorption maxima in the far-red region e.g., above 700 nm. Bacteriochlorin a (BCA), a non toxic derivative of bacteriochlorphyllin a, has a high molecular absorption coefficient (32.000 M-1.cm-1) at 760 nm. At this wavelength tissue penetration of light is almost optimal and melanin absorption is relatively low. In several series of experiments BCA was proven to be a very effective photosensitizer, in vitro and in vivo. It is preferentially retained in experimental hamster Greene melanoma, rhabdomyosarcoma, RIF- and mamma tumors. Its fluorescence can be detected in vivo, thus enabling early tumor detection and it is rapidly cleared from the tissues which promises no, or minor skin photosensitivity. The effects of BCA-PDT were studied in vitro and in vivo using the heavily pigmented Hamster Greene Melanoma (HGM) cell line as a model. In vitro it was found that the uptake of BCA was time, concentration and temperature dependant. Upon illumination (10 Mw/cm2, 756 nm) after incubation with 2.5 (mu) g/ml BCA for 1 h, almost complete cell kill was obtained within seconds. Hamster Greene Melanoma implanted in the anterior eye chamber of rabbits is an accepted in vivo model for ocular melanoma. The effects of BCA-PDT using this model were studied by light- and electron microscopy. Immediately after PDT intracellular spaces were enlarged and blood vessels were clotted with swollen erythrocytes. Electron microscopy showed fused inner and outer membranes and affected cristae mitchondriales of some mitochondria. With time, the severity of tissue and cell damage increased. One day after irradiation tumor growth had stopped; fluorescein angiography showed non perfusion of the tumor. Histopathology showed almost complete tumor necrosis with occasionally viable cells at the tumor periphery. It is concluded that the direct mitochondrial damage and the vascular damage both

Comparison of Bacterial Burden and Cytokine Gene Expression in Golden Hamsters in Early Phase of Infection with Two Different Strains of Leptospira interrogans.

PubMed

Fujita, Rie; Koizumi, Nobuo; Sugiyama, Hiromu; Tomizawa, Rina; Sato, Ryoichi; Ohnishi, Makoto

2015-01-01

Leptospirosis, a zoonotic infection with worldwide prevalence, is caused by pathogenic spirochaetes of Leptospira spp., and exhibits an extremely broad clinical spectrum in human patients. Although previous studies indicated that specific serovars or genotypes of Leptospira spp. were associated with severe leptospirosis or its outbreak, the mechanism underlying the difference in virulence of the various Leptospira serotypes or genotypes remains unclear. The present study addresses this question by measuring and comparing bacterial burden and cytokine gene expression in hamsters infected with strains of two L. interrogans serovars Manilae (highly virulent) and Hebdomadis (less virulent). The histopathology of kidney, liver, and lung tissues was also investigated in infected hamsters. A significantly higher bacterial burden was observed in liver tissues of hamsters infected with serovar Manilae than those infected with serovar Hebdomadis (p < 0.01). The average copy number of the leptospiral genome was 1,302 and 20,559 in blood and liver, respectively, of hamsters infected with serovar Manilae and 1,340 and 4,896, respectively, in hamsters infected with serovar Hebdomadis. The expression levels of mip1alpha in blood; tgfbeta, il1beta, mip1alpha, il10, tnfalpha and cox2 in liver; and tgfbeta, il6, tnfalpha and cox2 in lung tissue were significantly higher in hamsters infected with serovar Manilae than those infected with serovar Hebdomadis (p < 0.05). In addition, infection with serovar Manilae resulted in a significantly larger number of hamsters with tnfalpha upregulation (p = 0.04). Severe distortion of tubular cell arrangement and disruption of renal tubules in kidney tissues and hemorrhage in lung tissues were observed in Manilae-infected hamsters. These results demonstrate that serovar Manilae multiplied more efficiently in liver tissues and induced significantly higher expression of genes encoding pro- and anti-inflammatory cytokines than serovar Hebdomadis

Comparison of Bacterial Burden and Cytokine Gene Expression in Golden Hamsters in Early Phase of Infection with Two Different Strains of Leptospira interrogans

PubMed Central

Fujita, Rie; Koizumi, Nobuo; Sugiyama, Hiromu; Tomizawa, Rina; Sato, Ryoichi; Ohnishi, Makoto

2015-01-01

Leptospirosis, a zoonotic infection with worldwide prevalence, is caused by pathogenic spirochaetes of Leptospira spp., and exhibits an extremely broad clinical spectrum in human patients. Although previous studies indicated that specific serovars or genotypes of Leptospira spp. were associated with severe leptospirosis or its outbreak, the mechanism underlying the difference in virulence of the various Leptospira serotypes or genotypes remains unclear. The present study addresses this question by measuring and comparing bacterial burden and cytokine gene expression in hamsters infected with strains of two L. interrogans serovars Manilae (highly virulent) and Hebdomadis (less virulent). The histopathology of kidney, liver, and lung tissues was also investigated in infected hamsters. A significantly higher bacterial burden was observed in liver tissues of hamsters infected with serovar Manilae than those infected with serovar Hebdomadis (p < 0.01). The average copy number of the leptospiral genome was 1,302 and 20,559 in blood and liver, respectively, of hamsters infected with serovar Manilae and 1,340 and 4,896, respectively, in hamsters infected with serovar Hebdomadis. The expression levels of mip1alpha in blood; tgfbeta, il1beta, mip1alpha, il10, tnfalpha and cox2 in liver; and tgfbeta, il6, tnfalpha and cox2 in lung tissue were significantly higher in hamsters infected with serovar Manilae than those infected with serovar Hebdomadis (p < 0.05). In addition, infection with serovar Manilae resulted in a significantly larger number of hamsters with tnfalpha upregulation (p = 0.04). Severe distortion of tubular cell arrangement and disruption of renal tubules in kidney tissues and hemorrhage in lung tissues were observed in Manilae-infected hamsters. These results demonstrate that serovar Manilae multiplied more efficiently in liver tissues and induced significantly higher expression of genes encoding pro- and anti-inflammatory cytokines than serovar Hebdomadis

Efficient expression of stable recombinant human insulin-like growth factor-1 fusion with human serum albumin in Chinese hamster ovary cells.

PubMed

Wan, Aini; Xu, Dongsheng; Liu, Kedong; Peng, Lin; Cai, Yanfei; Chen, Yun; He, Yang; Yang, Jianfeng; Jin, Jian; Li, Huazhong

2017-08-09

Insulin-like growth factor-1 (IGF-1) plays a crucial role in cell development, differentiation, and metabolism, and has been a potential therapeutic agent for many diseases. Chinese hamster ovary (CHO) cells are widely used for production of recombinant therapeutic proteins, but the expression level of IGF-1 in CHO cells is very low (1,500 µg/L) and the half-life of IGF-1 in blood circulation is only 4.5 min according to previous studies. Therefore, IGF-1 was fused to long-circulating serum protein human serum albumin (HSA) and expressed in CHO cells. After 8-day fed-batch culture, the expression level of HSA-IGF-1 reached 100 mg/L. The fusion protein HSA-IGF-1 was purified with a recovery of 35% using a two-step chromatographic procedure. According to bioactivity assay, the purified HSA-IGF-1 could stimulate the proliferation of NIH3T3 cells in a dose-dependent fashion and promote the cell-cycle progression. Besides this, HSA-IGF-1 could bind to IGF-1 receptor on cell membrane and activate the intracellular PI3K/AKT signaling pathway. Our study suggested that HSA fusion technology carried out in CHO cells not only provided bioactivity in HSA-IGF-1 for further research but also offered a beneficial strategy to produce other similar cytokines in CHO cells.

A new species of Giardia Künstler, 1882 (Sarcomastigophora: Hexamitidae) in hamsters.

PubMed

Lyu, Zhangxia; Shao, Jingru; Xue, Min; Ye, Qingqing; Chen, Bing; Qin, Yan; Wen, Jianfan

2018-03-20

Giardia spp. are flagellated protozoan parasites that infect humans and many other vertebrates worldwide. Currently seven species of Giardia are considered valid. Here, we report a new species, Giardia cricetidarum n. sp. in hamsters. Trophozoites of G. cricetidarum n. sp. are pear-shaped with four pairs of flagella and measure on average 14 μm (range 12-18 μm) in length and 10 μm (range 8-12 μm) in width. The trophozoites of the new species are generally larger and stouter than those of most of the other Giardia spp. and exhibit the lowest length/width ratio (c.1.40) of all recognized Giardia species. Cysts of G. cricetidarum n. sp. are ovoid and measure on average 11 μm (range 9-12 μm) in length and 10 μm (range 8-10 μm) in width and are indistinguishable from the cysts of other Giardia species. Molecular phylogenetic analyses based on beta-giardin, small subunit rRNA, and elongation factor-1 alpha loci all demonstrated that G. cricetidarum n. sp. is genetically distinct from all currently accepted Giardia spp. Investigation of the host range indicated that the new species was only found in hamsters (including Phodopus sungorus, P. campbelli and Mesocricetus auratus), while all the other described mammal-parasitizing species (G. muris, G. microti and G. intestinalis) each infect multiple hosts. Cross-transmission studies further demonstrated the apparent host specificity of G. cricetidarum n. sp. as it only infected hamsters. Trophozoites were found in high numbers in hamster intestines (5 × 10 5 - 5 × 10 6 ) and was rarely detected co-infecting with other Giardia spp. in the common hamster, suggesting it has some advantages in parasitizing hamsters. This study has identified a new species of Giardia, which appears to be specific to hamsters, and together with the three other mammal-parasitizing Giardia species with different host ranges, may be able to be used as a model system for the study of evolutionary divergence of host parasitism strategies in

Reversion of 6-thioguanine resistant Chinese hamster cell lines: agent specificity and evidence for the repair of promutagenic lesions.

PubMed

Hodgkiss, R J; Brennand, J; Fox, M

1980-02-01

The kinetics and mutagen specificity of reversion of an HGPRT(-)TG(R) line of Chinese hamster cells have been examined in detail by measuring the frequency of HAT(R) colonies. Alkylating agents which produce relatively high levels of O-atom reaction were effective in inducing reversion. MMS, DMS and u.v. were less efficient, and aflatoxin B1, acridine orange and N-acetoxy-AAF were completely ineffective. For agents which were effective, the relationship between HAT(R) colony frequency and dose of mutagen was linear at early expression times (6 h). HAT(R) colony frequency fell subsequently at all doses and the rate and extent of the fall was inversely related to dose. These observations suggest repair of a pro-mutagenic DNA lesion. Other TG(R) mutants isolated from the same wild-type cell line under different selective conditions were also tested for revertibility after exposure to the same mutagens. The majority did not revert, this suggests that they carry deletions within the structural gene for HGPRT. The infrequent revertible lines all arose spontaneously and our evidence suggests that they carry nonsense mutations.

A Comparison of Hamster Anesthetics and Their Effect on Mosquito Blood Feeding

USDA-ARS?s Scientific Manuscript database

Hamsters or mice are often anesthetized when they are used as the hosts for insect feeding experiments. An experiment was done to determine if there was a difference in mosquito blood feeding success when fed on hamsters anesthetized using two commonly used protocols. The number of blood-fed females...

Investigation of defect properties in Cu(In,Ga)Se 2 solar cells by deep-level transient spectroscopy

NASA Astrophysics Data System (ADS)

Kerr, L. L.; Li, Sheng S.; Johnston, S. W.; Anderson, T. J.; Crisalle, O. D.; Kim, W. K.; Abushama, J.; Noufi, R. N.

2004-09-01

The performance of the chalcopyrite material Cu(In,Ga)Se 2 (CIGS) used as an absorber layer in thin-film photovoltaic devices is significantly affected by the presence of native defects. The deep-level transient spectroscopy (DLTS) technique is used in this work to characterize the defect properties, yielding relevant information about the defect types, their capture cross-sections, and energy levels and densities in the CIGS cells. Three solar cells developed using different absorber growth technologies were analyzed using DLTS, capacitance-voltage ( C- V), and capacitance-temperature ( C- T) techniques. It was found that CIS cells grown at the University of Florida exhibits a middle-gap defect level that may relate to the cell's low fill factor and open-circuit voltage values observed. A high efficiency ( ηc>18%) CIGS cell produced by the National Renewable Energy Laboratory (NREL) was found to contain three minority-carrier (electron) traps and a 13% CIGS cell produced by the Energy Photovoltaics Inc. (EPV) exhibited one majority (hole) trap. The approach followed using the DLTS technique serves as a paradigm for revealing the presence of significant defect levels in absorber materials, and may be used to support the identification of remedial processing operations.

The pathophysiology of human obstructive cholestasis is mimicked in cholestatic Gold Syrian hamsters.

PubMed

van Golen, Rowan F; Olthof, Pim B; de Haan, Lianne R; Coelen, Robert J; Pechlivanis, Alexandros; de Keijzer, Mark J; Weijer, Ruud; de Waart, Dirk R; van Kuilenburg, André B P; Roelofsen, Jeroen; Gilijamse, Pim W; Maas, Martinus A; Lewis, Matthew R; Nicholson, Jeremy K; Verheij, Joanne; Heger, Michal

2018-03-01

Obstructive cholestasis causes liver injury via accumulation of toxic bile acids (BAs). Therapeutic options for cholestatic liver disease are limited, partially because the available murine disease models lack translational value. Profiling of time-related changes following bile duct ligation (BDL) in Gold Syrian hamsters revealed a biochemical response similar to cholestatic patients in terms of BA pool composition, alterations in hepatocyte BA transport and signaling, suppression of BA production, and adapted BA metabolism. Hamsters tolerated cholestasis well for up to 28days and progressed relatively slowly to fibrotic liver injury. Hepatocellular necrosis was absent, which coincided with preserved intrahepatic energy levels and only mild oxidative stress. The histological response to cholestasis in hamsters was similar to the changes seen in 17 patients with prolonged obstructive cholestasis caused by cholangiocarcinoma. Hamsters moreover upregulated hepatic fibroblast growth factor 15 (Fgf15) expression in response to BDL, which is a cytoprotective adaptation to cholestasis that hitherto had only been documented in cholestatic human livers. Hamster models should therefore be added to the repertoire of animal models used to study the pathophysiology of cholestatic liver disease. Copyright © 2017 Elsevier B.V. All rights reserved.

Impact of wheel running on chronic ethanol intake in aged Syrian hamsters.

PubMed

Brager, Allison J; Hammer, Steven B

2012-10-10

Alcohol dependence in aging populations is seen as a public health concern, most recently because of the significant proportion of heavy drinking among "Baby Boomers." Basic animal research on the effects of aging on physiological and behavioral regulation of ethanol (EtOH) intake is sparse, since most of this research is limited to younger models of alcoholism. Here, EtOH drinking and preference were measured in groups of aged Syrian hamsters. Further, because voluntary exercise (wheel-running) is a rewarding substitute for EtOH in young adult hamsters, the potential for such reward substitution was also assessed. Aged (24 month-old) male hamsters were subjected to a three-stage regimen of free-choice EtOH (20% v/v) or water and unlocked or locked running wheels to investigate the modulatory effects of voluntary wheel running on EtOH intake and preference. Levels of fluid intake and activity were recorded daily across 60 days of experimentation. Prior to wheel running, levels of EtOH intake were significantly less than levels of water intake, resulting in a low preference for EtOH (30%). Hamsters with access to an unlocked running wheel had decreased EtOH intake and preference compared with hamsters with access to a locked running wheel. These group differences in EtOH intake and preference were sustained for up to 10 days after running wheels were re-locked. These results extend upon those of our previous work in young adult hamsters, indicating that aging dampens EtOH intake and preference. Voluntary wheel running further limited EtOH intake, suggesting that exercise could offer a practical approach for managing late-life alcoholism. Copyright © 2012 Elsevier Inc. All rights reserved.

Acute encephalitis, a poliomyelitis-like syndrome and neurological sequelae in a hamster model for flavivirus infections.

PubMed

Leyssen, Pieter; Croes, Romaric; Rau, Philipp; Heiland, Sabine; Verbeken, Erik; Sciot, Raphael; Paeshuyse, Jan; Charlier, Nathalie; De Clercq, Erik; Meyding-Lamadé, Uta; Neyts, Johan

2003-07-01

Infection of hamsters with the murine flavivirus Modoc results in (meningo)encephalitis, which is, during the acute phase, frequently associated with flaccid paralysis, as also observed in patients with West Nile virus encephalitis. Twenty percent of the hamsters that recover from the acute encephalitis develop life-long neurological sequelae, reminiscent of those observed, for example, in survivors of Japanese encephalitis. Magnetic resonance imaging and histology revealed severe lesions predominantly located in the olfactory-limbic system, both in hamsters with acute encephalitis as in survivors. Prominent pathology was also detected in the spinal cord of hamsters with paralysis. Modoc virus infections in hamsters provide a unique model for the study of encephalitis, a poliomyelitis-like syndrome and neurological sequelae following flavivirus infection.

A Lethal Disease Model for Hantavirus Pulmonary Syndrome in Immunosuppressed Syrian Hamsters Infected with Sin Nombre Virus

PubMed Central

Brocato, Rebecca L.; Hammerbeck, Christopher D.; Bell, Todd M.; Wells, Jay B.; Queen, Laurie A.

2014-01-01

Sin Nombre virus (SNV) is a rodent-borne hantavirus that causes hantavirus pulmonary syndrome (HPS) predominantly in North America. SNV infection of immunocompetent hamsters results in an asymptomatic infection; the only lethal disease model for a pathogenic hantavirus is Andes virus (ANDV) infection of Syrian hamsters. Efforts to create a lethal SNV disease model in hamsters by repeatedly passaging virus through the hamster have demonstrated increased dissemination of the virus but no signs of disease. In this study, we demonstrate that immunosuppression of hamsters through the administration of a combination of dexamethasone and cyclophosphamide, followed by infection with SNV, results in a vascular leak syndrome that accurately mimics both HPS disease in humans and ANDV infection of hamsters. Immunosuppressed hamsters infected with SNV have a mean number of days to death of 13 and display clinical signs associated with HPS, including pulmonary edema. Viral antigen was widely detectable throughout the pulmonary endothelium. Histologic analysis of lung sections showed marked inflammation and edema within the alveolar septa of SNV-infected hamsters, results which are similar to what is exhibited by hamsters infected with ANDV. Importantly, SNV-specific neutralizing polyclonal antibody administered 5 days after SNV infection conferred significant protection against disease. This experiment not only demonstrated that the disease was caused by SNV, it also demonstrated the utility of this animal model for testing candidate medical countermeasures. This is the first report of lethal disease caused by SNV in an adult small-animal model. PMID:24198421

A lethal disease model for hantavirus pulmonary syndrome in immunosuppressed Syrian hamsters infected with Sin Nombre virus.

PubMed

Brocato, Rebecca L; Hammerbeck, Christopher D; Bell, Todd M; Wells, Jay B; Queen, Laurie A; Hooper, Jay W

2014-01-01

Sin Nombre virus (SNV) is a rodent-borne hantavirus that causes hantavirus pulmonary syndrome (HPS) predominantly in North America. SNV infection of immunocompetent hamsters results in an asymptomatic infection; the only lethal disease model for a pathogenic hantavirus is Andes virus (ANDV) infection of Syrian hamsters. Efforts to create a lethal SNV disease model in hamsters by repeatedly passaging virus through the hamster have demonstrated increased dissemination of the virus but no signs of disease. In this study, we demonstrate that immunosuppression of hamsters through the administration of a combination of dexamethasone and cyclophosphamide, followed by infection with SNV, results in a vascular leak syndrome that accurately mimics both HPS disease in humans and ANDV infection of hamsters. Immunosuppressed hamsters infected with SNV have a mean number of days to death of 13 and display clinical signs associated with HPS, including pulmonary edema. Viral antigen was widely detectable throughout the pulmonary endothelium. Histologic analysis of lung sections showed marked inflammation and edema within the alveolar septa of SNV-infected hamsters, results which are similar to what is exhibited by hamsters infected with ANDV. Importantly, SNV-specific neutralizing polyclonal antibody administered 5 days after SNV infection conferred significant protection against disease. This experiment not only demonstrated that the disease was caused by SNV, it also demonstrated the utility of this animal model for testing candidate medical countermeasures. This is the first report of lethal disease caused by SNV in an adult small-animal model.

Gene expression analysis and microdialysis suggest hypothalamic triiodothyronine (T3) gates daily torpor in Djungarian hamsters (Phodopus sungorus).

PubMed

Bank, Jonathan H H; Cubuk, Ceyda; Wilson, Dana; Rijntjes, Eddy; Kemmling, Julia; Markovsky, Hanna; Barrett, Perry; Herwig, Annika

2017-07-01

Thyroid hormones play an important role in regulating seasonal adaptations of mammals. Several studies suggested that reduced availability of 3,3',5-triiodothyronine (T3) in the hypothalamus is required for the physiological adaptation to winter in Djungarian hamsters. We have previously shown that T3 is involved in the regulation of daily torpor, but it remains unclear, whether T3 affects torpor by central or peripheral mechanisms. To determine the effect of T3 concentrations within the hypothalamus in regulating daily torpor, we tested the hypothesis that low hypothalamic T3 metabolism would favour torpor and high T3 concentrations would not. In experiment 1 gene expression in torpid hamsters was assessed for transporters carrying thyroid hormones between cerebrospinal fluid and hypothalamic cells and for deiodinases enzymes, activating or inactivating T3 within hypothalamic cells. Gene expression analysis suggests reduced T3 in hypothalamic cells during torpor. In experiment 2, hypothalamic T3 concentrations were altered via microdialysis and torpor behaviour was continuously monitored by implanted body temperature transmitters. Increased T3 concentrations in the hypothalamus reduced expression of torpor as well as torpor bout duration and depth. Subsequent analysis of gene expression in the ependymal layer of the third ventricle showed clear up-regulation of T3 inactivating deiodinase 3 but no changes in several other genes related to photoperiodic adaptations in hamsters. Finally, serum analysis revealed that increased total T3 serum concentrations were not necessary to inhibit torpor expression. Taken together, our results are consistent with the hypothesis that T3 availability within the hypothalamus significantly contributes to the regulation of daily torpor via a central pathway.

Starvation induced cell death in autophagy-defective yeast mutants is caused by mitochondria dysfunction.

PubMed

Suzuki, Sho W; Onodera, Jun; Ohsumi, Yoshinori

2011-02-25

Autophagy is a highly-conserved cellular degradation and recycling system that is essential for cell survival during nutrient starvation. The loss of viability had been used as an initial screen to identify autophagy-defective (atg) mutants of the yeast Saccharomyces cerevisiae, but the mechanism of cell death in these mutants has remained unclear. When cells grown in a rich medium were transferred to a synthetic nitrogen starvation media, secreted metabolites lowered the extracellular pH below 3.0 and autophagy-defective mutants mostly died. We found that buffering of the starvation medium dramatically restored the viability of atg mutants. In response to starvation, wild-type (WT) cells were able to upregulate components of the respiratory pathway and ROS (reactive oxygen species) scavenging enzymes, but atg mutants lacked this synthetic capacity. Consequently, autophagy-defective mutants accumulated the high level of ROS, leading to deficient respiratory function, resulting in the loss of mitochondria DNA (mtDNA). We also showed that mtDNA deficient cells are subject to cell death under low pH starvation conditions. Taken together, under starvation conditions non-selective autophagy, rather than mitophagy, plays an essential role in preventing ROS accumulation, and thus in maintaining mitochondria function. The failure of response to starvation is the major cause of cell death in atg mutants.

Chinese hamster ovary K1 host cell enables stable cell line development for antibody molecules which are difficult to express in DUXB11-derived dihydrofolate reductase deficient host cell.

PubMed

Hu, Zhilan; Guo, Donglin; Yip, Shirley S M; Zhan, Dejin; Misaghi, Shahram; Joly, John C; Snedecor, Bradley R; Shen, Amy Y

2013-01-01

Therapeutic monoclonal antibodies (mAb) are often produced in Chinese hamster ovary (CHO) cells. Three commonly used CHO host cells for generating stable cell lines to produce therapeutic proteins are dihydrofolate reductase (DHFR) positive CHOK1, DHFR-deficient DG44, and DUXB11-based DHFR deficient CHO. Current Genentech commercial full-length antibody products have all been produced in the DUXB11-derived DHFR-deficient CHO host. However, it has been challenging to develop stable cell lines producing an appreciable amount of antibody proteins in the DUXB11-derived DHFR-deficient CHO host for some antibody molecules and the CHOK1 host has been explored as an alternative approach. In this work, stable cell lines were developed for three antibody molecules in both DUXB11-based and CHOK1 hosts. Results have shown that the best CHOK1 clones produce about 1 g/l for an antibody mAb1 and about 4 g/l for an antibody mAb2 in 14-day fed batch cultures in shake flasks. In contrast, the DUXB11-based host produced ∼0.1 g/l for both antibodies in the same 14-day fed batch shake flask production experiments. For an antibody mAb3, both CHOK1 and DUXB11 host cells can generate stable cell lines with the best clone in each host producing ∼2.5 g/l. Additionally, studies have shown that the CHOK1 host cell has a larger endoplasmic reticulum and higher mitochondrial mass. © 2013 American Institute of Chemical Engineers.

Altered Gene Expression Patterns During the Initiation and Promotion Stages of Neonatally Diethylstilbestrol-Induced Hyperplasia/Dysplasia/Neoplasia in the Hamster Uterus

PubMed Central

Hendry, William J.; Hariri, Hussam Y.; Alwis, Imala D.; Gunewardena, Sumedha S.; Hendry, Isabel R.

2014-01-01

Neonatal treatment of hamsters with diethylstilbestrol (DES) induces uterine hyperplasia/dysplasia/neoplasia (endometrial adenocarcinoma) in adult animals. We subsequently determined that the neonatal DES exposure event directly and permanently disrupts the developing hamster uterus (initiation stage) so that it responds abnormally when it is stimulated with estrogen in adulthood (promotion stage). To identify candidate molecular elements involved in progression of the disruption/neoplastic process, we performed: 1) immunoblot analyses and 2) microarray profiling (Affymetrix Gene Chip System) on sets of uterine protein and RNA extracts, respectively, and 3) immunohistochemical analysis on uterine sections; all from both initiation stage and promotion stage groups of animals. Here we report that: 1) progression of the neonatal DES-induced hyperplasia/dysplasia/neoplasia phenomenon in the hamster uterus involves a wide spectrum of specific gene expression alterations and 2) the gene products involved and their manner of altered expression differ dramatically during the initiation vs. promotion stages of the phenomenon. Particularly interesting changes included members in the functional categories of nuclear receptors (progesterone receptor), cell-cell interactions (E-cadherin, connexins), cytokine action (IRF-1, Stat5A), growth factor action (IRS-1), extracellular matrix component (tenascin-C), transcription factors (Nrf2, Sp1), and multi-functional nuclear protein (SAFB1). PMID:25242112

Topical photosan-mediated photodynamic therapy for DMBA-induced hamster buccal pouch early cancer lesions: an in vivo study

NASA Astrophysics Data System (ADS)

Hsu, Yih-Chih; Chang, Walter Hong-Shong; Chang, Junn-Liang; Liu, Kuang-Ting; Chiang, Chun-Pin; Liu, Chung-Ji; Chen, Chih-Ping

2011-03-01

Oral cancer has becomes the most prominent cancer disease in recent years in Taiwan. The reason is the betel nut chewing habit combing with smoking and alcohol-drinking lifestyle of people results in oral cancer becomes the fastest growth incident cancer amongst other major cancer diseases. In previous studies showed that photosan, haematoporphyrin derivative (HPD), has demonstrated effective PDT results on human head and neck disease studies. To avoid the systemic phototoxic effect of photosan, this study was designed to use a topical photosan-mediated PDT for treatment of DMBA-induced hamster buccal pouch cancerous lesions. DMBA was applied to one of the buccal pouches of hamsters thrice a week for 10 to 12 weeks. Cancerous lesions were induced and proven by histological examination. These DMBA-induced cancerous lesions were used for testing the efficacy of topical photosan-mediated PDT. Before PDT, fluorescence spectroscopy was used to determine when photosan reached its peak level in the lesional epithelial cells after topical application of photosan gel. We found that photosan reached its peak level in cancerous lesions about 13.5 min after topical application of photosan gel. The cancerous lesions in hamsters were then treated with topical photosan-mediated PDT (fluence rate: 600 mW/cm2; light exposure dose 200 J/cm2) using the portable Lumacare 635 nm fiber-guided light device. Visual examination demonstrated that topical photosan-mediated PDT was an applicable treatment modality for DMBA-induced hamster buccal pouch cancerous lesions.

Leptin mediates seasonal variation in some but not all symptoms of sickness in Siberian hamsters

PubMed Central

Carlton, Elizabeth D.; Demas, Gregory E.

2014-01-01

Many seasonally breeding species, including Siberian hamsters (Phodopus sungorus), exhibit seasonal variation in sickness responses. One hypothesis regarding the mechanism of this variation is that sickness intensity tracks an animal's energetic state, such that sickness is attenuated in the season that an animal has the lowest fat stores. Energetic state may be signaled via leptin, an adipose hormone that provides a signal of fat stores. Siberian hamsters respond to extended housing in short, winter-like days by reducing fat stores and leptin levels, relative to those housed in long, summer-like days. Sickness responses are also attenuated in short-day hamsters as compared to long-day hamsters. We hypothesized that leptin provides a physiological signal by which seasonally breeding animals modulate sickness responses, such that animals with higher leptin levels show increased sickness intensity. To test this, we provided short-day hamsters with a long-day-like leptin signal and assessed their responses to lipopolysaccharide (LPS), a sickness-inducing antigen. We compared these responses to short-day vehicle-, long-day vehicle-, and long-day leptin-treated hamsters. Unexpectedly, LPS induced a hypothermic response (rather than fever) in all groups. Short-day vehicle-treated hamsters exhibited the greatest LPS-induced hypothermia, and leptin treatment attenuated this response, making hypothermia more long-day-like. Contrary to our hypothesis, short-day leptin-treated hamsters showed the least pronounced LPS-induced anorexia among all groups. These results suggest that leptin may mediate some but not all aspects of seasonal sickness variation in this species. Future studies should be targeted at determining roles of other energetic hormones in regulating seasonal sickness response variation. PMID:25461974

[Screening of virulence gene in golden hamster cheek pouch mucosa carcinomatous change induced by 9,10-dimethylene-1,2-benzanthracene].

PubMed

Zhang, Guo-dong; Yang, Kai; Mei, Jie

2010-05-01

To examine and analyze the global gene expression at the different stages of golden hamster cheek pouch mucosa carcinomatous change induced by 9,10-dimethylene-1,2 benzanthracene (DMBA). The model of golden hamster cheek pouch squamous cell carcinoma was induced by DMBA. The RNA of normal mucosa, precancerous lesions and squamous cell carcinoma of fresh tissue of golden hamsters was extracted and purified and the cRNA labeled by fluorescent Cy3 synthesized, which respectively hybridized with the agilent rat cDNA microarray containing 41 000 genes-expressed sequence tags, scanning with Agilent G2565AA fluorescence scanner. The Ratio>or=2 and Ratiocell carcinoma, of which 2896 was up-regulated and 2359 down-regulated. There were 22 genes that showed continues abnormal expression through the three different stages of carcinomatous change, including 3 up-regulated, 19 down-regulated. The RT-PCR results of Eaf-2 and Ecg-2 were consistent with the gene chip. The development of oral mucosal squamous cell carcinoma involved a number of abnormal genes. The genes showing continues abnormal expression at different stages of carcinomatous change may be the important pathogenetic ones.

HPRT mutations in V79 Chinese hamster cells induced by accelerated Ni, Au and Pb ions.

PubMed

Stoll, U; Barth, B; Scheerer, N; Schneider, E; Kiefer, J

1996-07-01

Mutation induction by accelerated heavy ions to 6-TG resistance (HPRT system) in V79 Chinese hamster cells was investigated with Ni (6-630 Me V/u), Au (2.2, 8.7 Me V/u) and Pb ions (11.6-980 Me V/u) corresponding to a LET range between 180 and 12895 ke V/microns. Most experiments could only be performed once due to technical limitations using accelerator beam times. Survival curves were exponential, mutation induction curves linear with fluence. From their slopes inactivation- and mutation-induction cross-sections were derived. If they are plotted versus LET, single, ion-specific curves are obtained. It is shown that other parameters like ion energy and effective charge play an important role. In the case of Au and Pb ions the cross-sections follow a common line, since these ions have nearly the same atomic weight, so that they should have similar spatial ionization patterns in matter at the same energies. Calculated RBEs were higher for mutation induction than for killing for all LETs.

Vasopressin differentially modulates aggression and anxiety in adolescent hamsters administered anabolic steroids.

PubMed

Morrison, Thomas R; Ricci, Lesley A; Melloni, Richard H

2016-11-01

Adolescent Syrian hamsters (Mesocricetus auratus) treated with anabolic/androgenic steroids display increased offensive aggression and decreased anxiety correlated with an increase in vasopressin afferent development, synthesis, and neural signaling within the anterior hypothalamus. Upon withdrawal from anabolic/androgenic steroids, this neurobehavioral relationship shifts as hamsters display decreased offensive aggression and increased anxiety correlated with a decrease in anterior hypothalamic vasopressin. This study investigated the hypothesis that alterations in anterior hypothalamic vasopressin neural signaling modulate behavioral shifting between adolescent anabolic/androgenic steroid-induced offensive aggression and anxiety. To test this, adolescent male hamsters were administered anabolic/androgenic steroids and tested for offensive aggression or anxiety following direct pharmacological manipulation of vasopressin V1A receptor signaling within the anterior hypothalamus. Blockade of anterior hypothalamic vasopressin V1A receptor signaling suppressed offensive aggression and enhanced general and social anxiety in hamsters administered anabolic/androgenic steroids during adolescence, effectively reversing the pattern of behavioral response pattern normally observed during the adolescent exposure period. Conversely, activation of anterior hypothalamic vasopressin V1A receptor signaling enhanced offensive aggression in hamsters exposed to anabolic/androgenic steroids during adolescence. Together, these findings suggest that the state of vasopressin neural development and signaling in the anterior hypothalamus plays an important role in behavioral shifting between aggression and anxiety following adolescent exposure to anabolic/androgenic steroids. Copyright © 2016 Elsevier Inc. All rights reserved.

Vasopressin Differentially Modulates Aggression and Anxiety in Adolescent Hamsters Administered Anabolic Steroids

PubMed Central

Morrison, Thomas R.; Ricci, Lesley A.; Melloni, Richard H.

2016-01-01

Adolescent Syrian hamsters (Mesocricetus auratus) treated with anabolic/androgenic steroids display increased offensive aggression and decreased anxiety correlated with an increase in vasopressin afferent development, synthesis, and neural signaling within the anterior hypothalamus. Upon withdrawal from anabolic/androgenic steroids, this neurobehavioral relationship shifts as hamsters display decreased offensive aggression and increased anxiety correlated with a decrease in anterior hypothalamic vasopressin. This study investigated the hypothesis that alterations in anterior hypothalamic vasopressin neural signaling modulate behavioral shifting between adolescent anabolic/androgenic steroid-induced offensive aggression and anxiety. To test this, adolescent male hamsters were administered anabolic/androgenic steroids and tested for offensive aggression or anxiety following direct pharmacological manipulation of vasopressin V1A receptor signaling within the anterior hypothalamus. Blockade of anterior hypothalamic vasopressin V1A receptor signaling suppressed offensive aggression and enhanced general and social anxiety in hamsters administered anabolic/androgenic steroids during adolescence, effectively reversing the pattern of behavioral response pattern normally observed during the adolescent exposure period. Conversely, activation of anterior hypothalamic vasopressin V1A receptor signaling enhanced offensive aggression in hamsters exposed to anabolic/androgenic steroids during adolescence. Together, these findings suggest that the state of vasopressin neural development and signaling in the anterior hypothalamus plays an important role in behavioral shifting between aggression and anxiety following adolescent exposure to anabolic/androgenic steroids. PMID:27149949

Decreasing temperature shifts hippocampal function from memory formation to modulation of hibernation bout duration in Syrian hamsters.

PubMed

Arant, Ryan J; Goo, Marisa S; Gill, Phoebe D; Nguyen, Yen; Watson, Katherine D; Hamilton, Jock S; Horowitz, John M; Horwitz, Barbara A

2011-08-01

Previous studies in hibernating species have characterized two forms of neural plasticity in the hippocampus, long-term potentiation (LTP) and its reversal, depotentiation, but not de novo long-term depression (LTD), which is also associated with memory formation. Studies have also shown that histamine injected into the hippocampus prolonged hibernation bout duration. However, spillover into the ventricles may have affected brain stem regions, not the hippocampus. Here, we tested the hypothesis that decreased brain temperature shifts the major function of the hippocampus in the Syrian hamster (Mesocricetus auratus) from one of memory formation (via LTP, depotentiation, and de novo LTD) to increasing hibernation bout duration. We found reduced evoked responses in hippocampal CA1 pyramidal neurons following low-frequency stimulation in young (<30 days old) and adult (>60 days old) hamsters, indicating that de novo LTD was generated in hippocampal slices from both pups and adults at temperatures >20°C. However, at temperatures below 20°C, synchronization of neural assemblies (a requirement for LTD generation) was markedly degraded, implying that de novo LTD cannot be generated in hibernating hamsters. Nonetheless, even at temperatures below 16°C, pyramidal neurons could still generate action potentials that may traverse a neural pathway, suppressing the ascending arousal system (ARS). In addition, histamine increased the excitability of these pyramidal cells. Taken together, these findings are consistent with the hypothesis that hippocampal circuits remain operational at low brain temperatures in Syrian hamsters and suppress the ARS to prolong bout duration, even though memory formation is muted at these low temperatures.

Chronic inhalation exposure of hamsters to nickel-enriched fly ash

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

Wehner, A.P.; Dagle, G.E.; Milliman, E.M.

1981-10-01

Hamsters were chronically exposed to approx.70 ..mu..g/liter respirable nickel-enriched fly ash (NEFA) aerosol, approx.17 ..mu..g/liter NEFA, or approx.70 ..mu..g/liter fly ash (FA) for up to 20 months. A control group received sham exposures. The NEFA particles of respirable size contained approximately 6% nickel, compared to about 0.3% for FA. Five hamsters/group were sacrificed after 4, 8, 12, or 16 months of exposure. An additional five hamsters/group were withdrawn from exposure at the same intervals for lifelong observations. Exposures to NEFA had no significant effect on body weight and life span of the animals although heavy deposits of NEFA in themore » lungs were demonstrated. However, lung weights of the high NEFA- and of the FA-exposed animals were significantly higher than those of the low-NEFA group and the controls, and mean lung volumes were significantly larger for the high-NEFA grop and the FA group than for the low-NEFA group and the controls. Dust was deposited (anthracosis) in the lungs of all exposed hamsters. Incidence and severity of interstitial reaction and bronchiolization were significantly higher in the dust-exposed groups than in the sham-exposed controls. The severity of anthracosis, interstitial reaction, and bronchiolization was significantly lower in the low-NEFA group than in the high-NEFA and FA groups. While two malignant primary thorax tumors were found in two hamsters of the high-NEFA group, no statistically significant carcinogenesis was observed. Of the exposure-related changes, only anthracosis decreased after withdrawal from exposure. Pulmonary nickel burdens after 20 months of exposure suggest that the pulmonary clearance rate was slower in the high-NEFA group than in the low-NEFA group.« less

Sunitinib Improves Some Clinical Aspects and Reverts DMBA-Induced Hyperplasic Lesions in Hamster Buccal Pouch

PubMed Central

de Souza, Fernanda Lopes; Oliveira, Mariana; Nunes, Marianne Brochado; Serafim, Lucas Horstmann; Azambuja, Alan Arrieira; Braga, Luisa Maria G. de M.; Saur, Lisiani; de Souza, Maria Antonieta Lopes; Xavier, Léder Leal

2014-01-01

Oral squamous cell carcinoma (OSCC) is a public health problem. The hamster buccal pouch model is ideal for analyzing the development of OSCC. This research analysed the effects of sunitinib (tyrosine kinase inhibitor) in precancerous lesions induced by 7,12-dimethylbenz(a)anthracene (DMBA) in this model. Thirty-four male hamsters, divided into six groups: control—C (n = 7), acetone—A (n = 12), carbamide peroxide—CP (n = 5 ), acetone and CP—A+CP (n = 8), 1% DMBA in acetone and CP—DA+CP (n = 6), and 1% DMBA in acetone and CP and 4-week treatment with sunitinib—DA+CP+S (n = 7). The aspects evaluated were anatomopathological features (peribuccal area, paws, nose, and fur), histological sections of the hamster buccal pouches (qualitatively analyzed), epithelium thickness, and the rete ridge density (estimated). Sunitinib was unable to attenuate the decrease in weight gain induced by DMBA; no increase in volume was detected in the pouch and/or ulceration, observed in 43% of the animals in the DA+CP group. DA+CP groups presented a significant increase in rete ridge density compared to the control groups (P < 0.01) which was reverted by sunitinib in the DA+CP+S group. Sunitinib seems to have important benefits in early stage carcinogenesis and may be useful in chemoprevention. PMID:24693453

Omega 3 Fatty Acids Promote Macrophage Reverse Cholesterol Transport in Hamster Fed High Fat Diet

PubMed Central

Kasbi Chadli, Fatima; Nazih, Hassane; Krempf, Michel; Nguyen, Patrick; Ouguerram, Khadija

2013-01-01

The aim of this study was to investigate macrophage reverse cholesterol transport (RCT) in hamster, a CETP-expressing species, fed omega 3 fatty acids (ω3PUFA) supplemented high fat diet (HFD). Three groups of hamsters (n = 6/group) were studied for 20 weeks: 1) control diet: Control, 2) HFD group: HF and 3) HFD group supplemented with ω3PUFA (EPA and DHA): HFω3. In vivo macrophage-to-feces RCT was assessed after an intraperitoneal injection of 3H-cholesterol-labelled hamster primary macrophages. Compared to Control, HF presented significant (p<0.05) increase in body weight, plasma TG (p<0.01) and cholesterol (p<0.001) with an increase in VLDL TG and in VLDL and LDL cholesterol (p<0.001). Compared to HF, HFω3 presented significant decrease in body weight. HFω3 showed less plasma TG (p<0.001) and cholesterol (p<0.001) related to a decrease in VLDL TG and HDL cholesterol respectively and higher LCAT activity (p<0.05) compared to HF. HFω3 showed a higher fecal bile acid excretion (p<0.05) compared to Control and HF groups and higher fecal cholesterol excretion (p<0.05) compared to HF. This increase was related to higher gene expression of ABCG5, ABCA1 and SR-B1 in HFω3 compared to Control and HF groups (<0.05) and in ABCG1 and CYP7A1 compared to HF group (p<0.05). A higher plasma efflux capacity was also measured in HFω3 using 3H- cholesterol labeled Fu5AH cells. In conclusion, EPA and DHA supplementation improved macrophage to feces reverse cholesterol transport in hamster fed HFD. This change was related to the higher cholesterol and fecal bile acids excretion and to the activation of major genes involved in RCT. PMID:23613796

Neurotensin is an antagonist of the human neurotensin NT2 receptor expressed in Chinese hamster ovary cells.

PubMed

Vita, N; Oury-Donat, F; Chalon, P; Guillemot, M; Kaghad, M; Bachy, A; Thurneyssen, O; Garcia, S; Poinot-Chazel, C; Casellas, P; Keane, P; Le Fur, G; Maffrand, J P; Soubrie, P; Caput, D; Ferrara, P

1998-11-06

The human levocabastine-sensitive neurotensin NT2 receptor was cloned from a cortex cDNA library and stably expressed in Chinese hamster ovary (CHO) cells in order to study its binding and signalling characteristics. The receptor binds neurotensin as well as several other ligands already described for neurotensin NT1 receptor. It also binds levocabastine, a histamine H1 receptor antagonist that is not recognised by neurotensin NT1 receptor. Neurotensin binding to recombinant neurotensin NT2 receptor expressed in CHO cells does not elicit a biological response as determined by second messenger measurements. Levocabastine, and the peptides neuromedin N and xenin were also ineffective on neurotensin NT2 receptor activation. Experiments with the neurotensin NT1 receptor antagonists SR48692 and SR142948A, resulted in the unanticipated discovery that both molecules are potent agonists on neurotensin NT2 receptor. Both compounds, following binding to neurotensin NT2 receptor, enhance inositol phosphates (IP) formation with a subsequent [Ca2+]i mobilisation; induce arachidonic acid release; and stimulate mitogen-activated protein kinase (MAPK) activity. Interestingly, these activities are antagonised by neurotensin and levocabastine in a concentration-dependent manner. These activities suggest that the human neurotensin NT2 receptor may be of physiological importance and that a natural agonist for the receptor may exist.

Efficacy of 2'-C-methylcytidine against yellow fever virus in cell culture and in a hamster model.

PubMed

Julander, Justin G; Jha, Ashok K; Choi, Jung-Ae; Jung, Kie-Hoon; Smee, Donald F; Morrey, John D; Chu, Chung K

2010-06-01

Yellow fever virus (YFV) continues to cause outbreaks of disease in endemic areas where vaccine is underutilized. Due to the effectiveness of the vaccine, antiviral development solely for the treatment of YFV is not feasible, but antivirals that are effective in the treatment of related viral diseases may be characterized for potential use against YFV as a secondary indication disease. 2'-C-methylcytidine (2'-C-MeC), a compound active against hepatitis C virus, was found to have activity against the 17D vaccine strain of YFV in cell culture (EC(90)=0.32 microg/ml, SI=141). This compound was effective when added as late as 16 h after virus challenge of Vero cells. When administered to YFV-infected hamsters 4 h prior to virus challenge at a dose as low as 80 mg/kg/d, 2'-C-MeC was effective in significantly improving survival and other disease parameters (weight change, serum ALT, and liver virus titers). Disease was improved when compound was administered beginning as late as 3 d post-virus infection. Broadly active antiviral compounds, such as 2'-C-MeC, represent potential for the development of compounds active against related viruses for the treatment of YFV. Copyright 2010 Elsevier B.V. All rights reserved.

Analysis of mutant quantity and quality in human-hamster hybrid AL and AL-179 cells exposed to 137Cs-gamma or HZE-Fe ions

NASA Technical Reports Server (NTRS)

Waldren, C.; Vannais, D.; Drabek, R.; Gustafson, D.; Kraemer, S.; Lenarczyk, M.; Kronenberg, A.; Hei, T.; Ueno, A.; Chatterjee, A. (Principal Investigator)

1998-01-01

We measured the number of mutants and the kinds of mutations induced by 137Cs-gamma and by HZE-Fe (56Fe [600 MeV/amu, LET = 190 KeV/micrometer) in standard AL human hamster hybrid cells and in a new variant hybrid, AL-179. We found that HZE-Fe was more mutagenic than 137Cs-gamma per unit dose (about 1.6 fold), but was slightly less mutagenic per mean lethal dose, DO, at both the S1 and hprt- loci of AL cells. On the other hand, HZE-Fe induced about nine fold more complex S1- mutants than 137Cs-gamma rays, 28% vs 3%. 137Cs-gamma rays induced about twice as many S1- mutants and hprt-mutants in AL-179 as in AL cells, and about nine times more of the former were complex, and potentially unstable kinds of mutations.

Winning agonistic encounters increases testosterone and androgen receptor expression in Syrian Hamsters

PubMed Central

Clinard, Catherine T.; Barnes, Abigail K.; Adler, Samuel G.; Cooper, Matthew A.

2016-01-01

Winning aggressive disputes is one of several experiences that can alter responses to future stressful events. We have previously tested dominant and subordinate male Syrian hamsters in a conditioned defeat model and found that dominant individuals show less change in behavior following social defeat stress compared to subordinates and controls, indicating a reduced conditioned defeat response. Resistance to the effects of social defeat in dominants is experience-dependent and requires the maintenance of dominance relationships for 14 days. For this study we investigated whether winning aggressive interactions increases plasma testosterone and whether repeatedly winning increases androgen receptor expression. First, male hamsters were paired in daily 10-min aggressive encounters and blood samples were collected immediately before and 15-min and 30-min after the formation of dominance relationships. Dominants showed an increase in plasma testosterone at 15-min post-interaction compared to their pre-interaction baseline, whereas subordinates and controls showed no change in plasma testosterone. Secondly, we investigated whether 14 days of dominant social status increased androgen or estrogen alpha-receptor immunoreactivity in brain regions that regulate the conditioned defeat response. Dominants showed more androgen, but not estrogen alpha, receptor immuno-positive cells in the dorsal medial amygdala (dMeA) and ventral lateral septum (vLS) compared to subordinates and controls. Finally, we showed that one day of dominant social status was insufficient to increase androgen receptor immunoreactivity compared to subordinates. These results suggest that elevated testosterone signaling at androgen receptors in the dMeA and vLS might contribute to the reduced conditioned defeat response exhibited by dominant hamsters. PMID:27619945

[Decorative forms of hamsters Phodopus (Mammalia, Cricetinae): an analysis of genetic lines distribution and peculiarities of hair changes].

PubMed

Feoktistova, N Iu; Chernova, O F; Meshcherskiĭ, I G

2012-01-01

Three species of dwarf hamsters (genus Phodopus, family Cricetidae) inhabit some regions of Russia, Kazakhstan, Mongolia, and China, each having quite extensive range. In recent decades, the dwarf hamsters became widely spread all over the world, initially as laboratory animals and later as popular pets. By now, there is lot of decorative breed lines and colored forms of these animals. Comparison of mtDNA nucleotide sequences of dwarf hamsters acquired in pet shops of some countries in Europe, South-East Asia and North America with distribution of mtDNA haplotypes within natural ranges showed the limitation of decorative line founders' points of origin by one region for each of the species. All haplotypes found in decorative Dzungarian hamsters (Ph. sungorus) purchased ounside Russia coincide with or are significantly close to haplotypes spread in the southern part of West Siberia (Russia) and adjacent regions of Kazakhstan; haplotypes of decorative Campbell's hamster (Ph. campbelli) belong to haplogroup of this species natural populations inhabiting South Tyva (Russia); and all studied decorative Desert hamsters (Ph. roborovskii) had one hapotype specific for South-Eastern Kazakhstan. The review of the history of researches on dwarf hamsters biology allows to determine delivery of hamsters from mentioned regions to scientific laboratories and zoos by certain expeditions and/or researchers. Unlike hamsters with natural hair color, the colored hamsters have no normal hair. Their hair is dull and straggly. The hair differentiation (presence of different hair types and their size characteristics) gets broken and results in deformation, bending, and splitting of the shaft, cracks in cuticle, change of configuration and location of medulla, uneven development of cortex. It is assumed that these destructive changes are associated with genetic characteristics of these hamsters' colored forms.

Dicholesteroyl diselenide: cytotoxicity, genotoxicity and mutagenicity in the yeast Saccharomyces cerevisiae and in Chinese hamster lung fibroblasts.

PubMed

de Oliveira, Iuri Marques; Degrandi, Tiago Hoerbe; Jorge, Patrícia Mendes; Saffi, Jenifer; Rosa, Renato Moreira; Guecheva, Temenouga Nikolova; Henriques, João Antonio Pêgas

2014-03-15

The organoselenium compound, dicholesteroyl diselenide (DCDS) is a structural analogue of diphenyl diselenide (DPDS) and may be considered as a promising antioxidant drug in vivo. Nevertheless, little is known about the toxicological properties of DCDS. In the present study we evaluated the cytotoxic, genotoxic and mutagenic properties of DCDS in Chinese hamster lung fibroblasts (V79) and in strains of the yeast Saccharomyces cerevisiae, proficient and deficient in several DNA-repair pathways. The results with V79 cells show that DCDS induced cytotoxicity, GSH depletion and elevation of lipid peroxidation at lower concentrations than did DPDS. DCDS also generated single- and double-strand DNA breaks in V79 cells, both in the presence and in the absence of metabolic activation, as revealed by alkaline and neutral comet assays. Moreover, the induction of oxidative DNA base-damage was demonstrated by means of a modified comet assay with formamidopyrimidine-DNA glycosylase and endonuclease III. Treatment with DCDS also induced micronucleus formation in V79 cells as well as point and frame-shift mutations in a haploid wild-type strain of S. cerevisiae. Yeast mutants defective in base excision-repair proteins were the most sensitive to DCDS. Pre-incubation with N-acetylcysteine reduced DCDS's oxidative, genotoxic and mutagenic effects in yeast and in V79 cells. Our findings indicate that the presence of cholesteroyl substituents in DCDS results in elevation of its cytotoxic and genotoxic potential compared with that of DPDS in yeast and in V79 cells. However, due to dose-dependent contrasting behaviour of organoselenium compounds and differences in their toxicity in in vitro and in vivo systems, further studies are needed in order to establish the non-toxic concentration range for treatment in mammals. Copyright © 2014 Elsevier B.V. All rights reserved.

Circadian body temperature variability is an indicator of poor prognosis in cardiomyopathic hamsters.

PubMed

Ahmed, Amany; Gondi, Sreedevi; Cox, Casey; Wang, Suwei; Stupin, Igor V; Shankar, K J; Munir, Shahzeb M; Sobash, Ed; Brewer, Alan; Ferguson, James J; Elayda, Macarthur A; Casscells, S Ward; Wilson, James M

2010-03-01

Low body temperature is an independent predictor of poor prognosis in patients with congestive heart failure. The cardiomyopathic hamster develops progressive biventricular dysfunction, resulting in heart failure death at 9 months to 1 year of life. Our goal was to use cardiomyopathic hamsters to examine the relationship between body temperature and heart failure decompensation and death. To this end, we implanted temperature and activity transducers with telemetry into the peritoneal space of 46 male Bio-TO-2 Syrian cardiomyopathic hamsters. Multiple techniques, including computing mean temperature, frequency domain analysis, and nonlinear analysis, were used to determine the most useful method for predicting poor prognosis. Data from 44 hamsters were included in our final analysis. We detected a decline in core body temperature in 98% of the hamsters 8+/-4 days before death (P < .001). We examined the dominant frequency of temperature variation (ie, the circadian rhythm) by using cosinor analysis, which revealed a significant decrease in the amplitude of the body temperature circadian rhythm 8 weeks before death (0.28 degrees C; 95% CI, 0.26-0.31) compared to baseline (0.36 degrees C; 95% CI, 0.34-0.39; P=.005). The decline in the circadian temperature variation preceded all other evidence of decompensation. We conclude that a decrease in the amplitude of the body temperature circadian rhythm precedes fatal decompensation in cardiomyopathic hamsters. Continuous temperature monitoring may be useful in predicting preclinical decompensation in patients with heart failure and in identifying opportunities for therapeutic intervention. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Evaluation of the mutagenic and cytotoxic effects of mercurous chloride by the micronuclei technique in golden Syrian hamsters.

PubMed

Cortés-Gutiérrez, Elva I; Cerda-Flores, Ricardo M; González-Ramírez, Diego; Zúñiga-Charles, Miguel A; Lazcano-Martínez, Sigifredo; Sampayo-Reyes, Adriana; Leal-Garza, Carlos H

2004-05-01

The aims of this study were to evaluate the mutagenic and cytotoxic activity of mercurous chloride by the micronucleus technique in vivo on the bone marrow of golden Syrian hamsters after a single i.p. drug administration. Forty male golden Syrian hamsters were classified into eight groups: negative control, positive control and six groups treated with different doses of mercurous chloride (1.25, 2.5, 5, 10, 20 and 40 mg/kg). The negative control was injected with physiological saline i.p. and the positive control with cyclophosphamide at a dose of 80 mg/kg i.p. With respect to mutagenic effect, the average number of micronucleated polychromatic erythrocytes (MPE) in hamsters treated with different doses of mercurous chloride was not significant compared with the negative control. With respect to cytotoxic effect, the average polychromatic erythrocyte/red blood cell ratio showed a significant decrease when the doses were higher than the 2.5 mg/kg dose compared with the negative control. In conclusion, this preliminary study shows a cytotoxic effect but not a mutagenic effect of calomel in vivo at one time point (24 h).

Zyflamend reduces LTB4 formation and prevents oral carcinogenesis in a 7,12-dimethylbenz[alpha]anthracene (DMBA)-induced hamster cheek pouch model.

PubMed

Yang, Peiying; Sun, Zheng; Chan, Diana; Cartwright, Carrie A; Vijjeswarapu, Mary; Ding, Jibin; Chen, Xiaoxin; Newman, Robert A

2008-11-01

Aberrant arachidonic acid metabolism, especially altered cyclooxygenase and 5-lipoxygenase (LOX) activities, has been associated with chronic inflammation as well as carcinogenesis in human oral cavity tissues. Here, we examined the effect of Zyflamend, a product containing 10 concentrated herbal extracts, on development of 7,12-dimethylbenz[alpha]anthracene (DMBA)-induced inflammation and oral squamous cell carcinoma (SCC). A hamster cheek pouch model was used in which 0.5% DMBA was applied topically onto the left cheek pouch of male Syrian golden hamsters either three times per week for 3 weeks (short term) or 6 weeks (long term). Zyflamend was then applied topically at one of three different doses (25, 50 and 100 microl) onto the left cheek pouch three times for 1 week (short-term study) or chronically for 18 weeks. Zyflamend significantly reduced infiltration of inflammatory cells, incidence of hyperplasia and dysplastic lesions, bromodeoxyuridine-labeling index as well as number of SCC in a concentration-dependent manner. Application of Zyflamend (100 microl) reduced formation of leukotriene B(4) (LTB(4)) by 50% compared with DMBA-treated tissues. The reduction of LTB(4) was concentration dependent. The effect of Zyflamend on inhibition of LTB(4) formation was further confirmed with in vitro cell-based assay. Adding LTB(4) to RBL-1 cells, a rat leukemia cell line expressing high levels of 5-LOX and LTA(4) hydrolase, partially blocked antiproliferative effect of Zyflamend. This study demonstrates that Zyflamend inhibited LTB(4) formation and modulated adverse histopathological changes in the DMBA-induced hamster cheek pouch model. The study suggests that Zyflamend might prevent oral carcinogenesis at the post-initiation stage.

Modified multiple drug resistance phenotype of Chinese hamster ovary cells selected with X-rays and vincristine versus X-rays only.

PubMed Central

McClean, S.; Hill, B. T.

1994-01-01

Exposure of Chinese hamster ovary (CHO) cells to fractionated X-irradiation [ten fractions of 9 Gray (Gy)] resulted in the expression of a multiple drug resistance phenotype which was distinct from that of drug-selected cells in two features: (i) resistance to vinca alkaloids and epipodophyllotoxins but sensitivity to anthracyclines was retained; (ii) overexpression of P-glycoprotein (Pgp) but regulated by post-translational stability rather than by any elevation in Pgp mRNA (Hill et al., 1990). It was also reported that when these cells (designated DXR-10) were subsequently exposed to another ten fractions of 9 Gy (20 x 9 Gy in total), no further increases in drug resistance or in the extent of Pgp expression were observed. To examine this apparent plateauing of the drug resistance phenotype following X-ray pretreatment, DXR-10 cells were instead treated with ten pulsed vincristine exposures. The resultant cell line, designated DXR-10/VCR-10, proved to be more resistant to vincristine, implying that the effect of further drug selection was additive to that of X-ray pretreatment. In addition, these cells showed resistance to doxorubicin and increased Pgp expression which was matched by a concomitant elevation in Pgp mRNA. These findings appear to confirm that Pgp expression is differentially regulated in tumour cells showing drug resistance after drug as opposed to X-ray selection. Images Figure 2 Figure 3 Figure 5 PMID:7908216

Defective calmodulin-dependent rapid apical endocytosis in zebrafish sensory hair cell mutants.

PubMed

Seiler, C; Nicolson, T

1999-11-15

Vertebrate mechanosensory hair cells contain a narrow "pericuticular" zone which is densely populated with small vesicles between the cuticular plate and cellular junctions near the apical surface. The presence of many cytoplasmic vesicles suggests that the apical surface of hair cells has a high turnover rate. The significance of intense membrane trafficking at the apical surface is not known. Using a marker of endocytosis, the styryl dye FM1-43, this report shows that rapid apical endocytosis in zebrafish lateral line sensory hair cells is calcium and calmodulin dependent and is partially blocked by the presence of amiloride and dihydrostreptomycin, known inhibitors of mechanotransduction channels. As seen in lateral line hair cells, sensory hair cells within the larval otic capsule also exhibit rapid apical endocytosis. Defects in internalization of the dye in both lateral line and inner ear hair cells were found in five zebrafish auditory/vestibular mutants: sputnik, mariner, orbiter, mercury, and skylab. In addition, lateral line hair cells in these mutants were not sensitive to prolonged exposure to streptomycin, which is toxic to hair cells. The presence of endocytic defects in the majority of zebrafish mechanosensory mutants points to a important role of apical endocytosis in hair cell function. Copyright 1999 John Wiley & Sons, Inc.

Comparison of repair of DNA double-strand breaks in identical sequences in primary human fibroblast and immortal hamster-human hybrid cells harboring a single copy of human chromosome 11

NASA Technical Reports Server (NTRS)

Fouladi, B.; Waldren, C. A.; Rydberg, B.; Cooper, P. K.; Chatterjee, A. (Principal Investigator)

2000-01-01

We have optimized a pulsed-field gel electrophoresis assay that measures induction and repair of double-strand breaks (DSBs) in specific regions of the genome (Lobrich et al., Proc. Natl. Acad. Sci. USA 92, 12050-12054, 1995). The increased sensitivity resulting from these improvements makes it possible to analyze the size distribution of broken DNA molecules immediately after the introduction of DSBs and after repair incubation. This analysis shows that the distribution of broken DNA pieces after exposure to sparsely ionizing radiation is consistent with the distribution expected from randomly induced DSBs. It is apparent from the distribution of rejoined DNA pieces after repair incubation that DNA ends continue to rejoin between 3 and 24 h postirradiation and that some of these rejoining events are in fact misrejoining events, since novel restriction fragments both larger and smaller than the original fragment are generated after repair. This improved assay was also used to study the kinetics of DSB rejoining and the extent of misrejoining in identical DNA sequences in human GM38 cells and human-hamster hybrid A(L) cells containing a single human chromosome 11. Despite the numerous differences between these cells, which include species and tissue of origin, levels of TP53, expression of telomerase, and the presence or absence of a homologous chromosome for the restriction fragments examined, the kinetics of rejoining of radiation-induced DSBs and the extent of misrejoining were similar in the two cell lines when studied in the G(1) phase of the cell cycle. Furthermore, DSBs were removed from the single-copy human chromosome in the hamster A(L) cells with similar kinetics and misrejoining frequency as at a locus on this hybrid's CHO chromosomes.

Alterations of male sexual behavior by learned aversions to hamster vaginal secretion.

PubMed

Johnston, R E; Zahorik, D M; Immler, K; Zakon, H

1978-02-01

Male hamsters poisoned after their first adult exposure to the vaginal secretion of female hamsters became hesitant to approach and ingest the secretion. The same aversion-training procedure also altered the responses of males to estrous females, changing the latency, frequency, and duration of a variety of behaviors that are commonly taken as indexes of sexual attraction or arousal and of copulatory performance. The effects suggest that the aversions to vaginal secretion alter the perceived meaning of the secretion for male hamsters, and analysis of the correlations between various measures of sexual arousal and performance support the hypothesis that separate mechanisms underlie the effects of the secretion on appetitive and consummatory sexual behavior.

Tuning of defects in ZnO nanorod arrays used in bulk heterojunction solar cells

PubMed Central

2012-01-01

With particular focus on bulk heterojunction solar cells incorporating ZnO nanorods, we study how different annealing environments (air or Zn environment) and temperatures impact on the photoluminescence response. Our work gives new insight into the complex defect landscape in ZnO, and it also shows how the different defect types can be manipulated. We have determined the emission wavelengths for the two main defects which make up the visible band, the oxygen vacancy emission wavelength at approximately 530 nm and the zinc vacancy emission wavelength at approximately 630 nm. The precise nature of the defect landscape in the bulk of the nanorods is found to be unimportant to photovoltaic cell performance although the surface structure is more critical. Annealing of the nanorods is optimum at 300°C as this is a sufficiently high temperature to decompose Zn(OH)2 formed at the surface of the nanorods during electrodeposition and sufficiently low to prevent ITO degradation. PMID:23186280

Delay of behavioral estrus in hamsters and phenobarbital.

PubMed

Alleva, J J

1989-01-01

The onset of behavioral estrus was used as a phase marker of the hamster timing system in SLD 16:8 (dark 20:00-04:00). TZ was injected between 11:00 of cycle day 3 and noon of cycle day 4 when onset of estrus was determined. At no time did injection of TZ cause a phase advance in SLD 16:8. Small delays of estrus resulted from 11:00-16:00 injections but marked delays began with the 17:00 injection. Phenobarbital was injected between noon and 19:30 on cycle day 3. Injections between noon and 16:00 had no effect but all later injections beginning at 17:00 delayed estrus, the 17:30 injection causing the greatest delay. Diazepam also markedly delayed estrus when tested at 17:30. These results with three drugs support results with light pulses that 18:00 in SLD 16:8 marks the same phase of the 24-h hamster timing system as the onset of wheel running does in DD, LL, and WLD. These findings with three GABA potentiators extend to SLD previous evidence based on the onset of wheel running in DD, LL and WLD that GABA may be involved in hamster timekeeping and its responses to light and drugs.

Genomic Instability in Human Pluripotent Stem Cells Arises from Replicative Stress and Chromosome Condensation Defects.

PubMed

Lamm, Noa; Ben-David, Uri; Golan-Lev, Tamar; Storchová, Zuzana; Benvenisty, Nissim; Kerem, Batsheva

2016-02-04

Human pluripotent stem cells (hPSCs) frequently acquire chromosomal aberrations such as aneuploidy in culture. These aberrations progressively increase over time and may compromise the properties and clinical utility of the cells. The underlying mechanisms that drive initial genomic instability and its continued progression are largely unknown. Here, we show that aneuploid hPSCs undergo DNA replication stress, resulting in defective chromosome condensation and segregation. Aneuploid hPSCs show altered levels of actin cytoskeletal genes controlled by the transcription factor SRF, and overexpression of SRF rescues impaired chromosome condensation and segregation defects in aneuploid hPSCs. Furthermore, SRF downregulation in diploid hPSCs induces replication stress and perturbed condensation similar to that seen in aneuploid cells. Together, these results suggest that decreased SRF expression induces replicative stress and chromosomal condensation defects that underlie the ongoing chromosomal instability seen in aneuploid hPSCs. A similar mechanism may also operate during initiation of instability in diploid cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Proinsulin atypical maturation and disposal induces extensive defects in mouse Ins2+/Akita β-cells.

PubMed

Yuan, Qingxin; Tang, Wei; Zhang, Xiaoping; Hinson, Jack A; Liu, Chao; Osei, Kwame; Wang, Jie

2012-01-01

Because of its low relative folding rate and plentiful manufacture in β-cells, proinsulin maintains a homeostatic balance of natively and plentiful non-natively folded states (i.e., proinsulin homeostasis, PIHO) through the integration of maturation and disposal processes. PIHO is susceptible to genetic and environmental influences, and its disorder has been critically linked to defects in β-cells in diabetes. To explore this hypothesis, we performed polymerase chain reaction (PCR), metabolic-labeling, immunoblotting, and histological studies to clarify what defects result from primary disorder of PIHO in model Ins2(+/Akita) β-cells. We used T antigen-transformed Ins2(+/Akita) and control Ins2(+/+) β-cells established from Akita and wild-type littermate mice. In Ins2(+/Akita) β-cells, we found no apparent defect at the transcriptional and translational levels to contribute to reduced cellular content of insulin and its precursor and secreted insulin. Glucose response remained normal in proinsulin biosynthesis but was impaired for insulin secretion. The size and number of mature insulin granules were reduced, but the size/number of endoplasmic reticulum, Golgi, mitochondrion, and lysosome organelles and vacuoles were expanded/increased. Moreover, cell death increased, and severe oxidative stress, which manifested as increased reactive oxygen species, thioredoxin-interacting protein, and protein tyrosine nitration, occurred in Ins2(+/Akita) β-cells and/or islets. These data show the first clear evidence that primary PIHO imbalance induces severe oxidative stress and impairs glucose-stimulated insulin release and β-cell survival as well as producing other toxic consequences. The defects disclosed/clarified in model Ins2(+/Akita) β-cells further support a role of the genetic and stress-susceptible PIHO disorder in β-cell failure and diabetes.

Proinsulin Atypical Maturation and Disposal Induces Extensive Defects in Mouse Ins2+/Akita β-Cells

PubMed Central

Zhang, Xiaoping; Hinson, Jack A.; Liu, Chao; Osei, Kwame; Wang, Jie

2012-01-01

Because of its low relative folding rate and plentiful manufacture in β-cells, proinsulin maintains a homeostatic balance of natively and plentiful non-natively folded states (i.e., proinsulin homeostasis, PIHO) through the integration of maturation and disposal processes. PIHO is susceptible to genetic and environmental influences, and its disorder has been critically linked to defects in β-cells in diabetes. To explore this hypothesis, we performed polymerase chain reaction (PCR), metabolic-labeling, immunoblotting, and histological studies to clarify what defects result from primary disorder of PIHO in model Ins2+/Akita β-cells. We used T antigen-transformed Ins2+/Akita and control Ins2+/+ β-cells established from Akita and wild-type littermate mice. In Ins2+/Akita β-cells, we found no apparent defect at the transcriptional and translational levels to contribute to reduced cellular content of insulin and its precursor and secreted insulin. Glucose response remained normal in proinsulin biosynthesis but was impaired for insulin secretion. The size and number of mature insulin granules were reduced, but the size/number of endoplasmic reticulum, Golgi, mitochondrion, and lysosome organelles and vacuoles were expanded/increased. Moreover, cell death increased, and severe oxidative stress, which manifested as increased reactive oxygen species, thioredoxin-interacting protein, and protein tyrosine nitration, occurred in Ins2+/Akita β-cells and/or islets. These data show the first clear evidence that primary PIHO imbalance induces severe oxidative stress and impairs glucose-stimulated insulin release and β-cell survival as well as producing other toxic consequences. The defects disclosed/clarified in model Ins2+/Akita β-cells further support a role of the genetic and stress-susceptible PIHO disorder in β-cell failure and diabetes. PMID:22509386

Renal atrial natriuretic factor receptors in hamster cardiomyopathy.

PubMed

Mukaddam-Daher, S; Jankowski, M; Dam, T V; Quillen, E W; Gutkowska, J

1995-12-01

Hamsters with cardiomyopathy (CMO), an experimental model of congestive heart failure, display stimulated renin-angiotensin-aldosterone and enhanced sympathetic nervous activity, all factors that lead to sodium retention, volume expansion and subsequent elevation of plasma atrial natriuretic factor (ANF) by the cardiac atria. However, sodium and water retention persist in CMO, indicating hyporesponsiveness to endogenous ANF. These studies were undertaken to fully characterize renal ANF receptor subtypes in normal hamsters and to evaluate whether alterations in renal ANF receptors may contribute to renal resistance to ANF in cardiomyopathy. Transcripts of the guanylyl cyclase-A (GC-A) and guanylyl cyclase B (GC-B) receptors were detected by quantitative polymerase chain reaction (PCR) in renal cortex, and outer and inner medullas. Compared to normal controls, the cardiomyopathic hamster's GC-A mRNA was similar in cortex but significantly increased in outer and inner medulla. Levels of GC-B mRNA were not altered by the disease. On the other hand, competitive binding studies, autoradiography, and affinity cross-linking demonstrated the absence of functional GC-B receptors in the kidney glomeruli and inner medulla. Also, C-type natriuretic peptide (CNP), the natural ligand for the GC-B receptors, failed to stimulate glomerular production of its second messenger cGMP. In CMO, sodium and water excretion were significantly reduced despite elevated plasma ANF (50.5 +/- 11.1 vs. 309.4 +/- 32.6 pg/ml, P < 0.001). Competitive binding studies of renal glomerular ANF receptors revealed no change in total receptor density, Bmax (369.6 +/- 27.4 vs. 282.8 +/- 26.2 fmol/mg protein), nor in dissociation constant, Kd (647.4 +/- 79.4 vs. 648.5 +/- 22.9 pM). Also, ANF-C receptor density (254.3 +/- 24.8 vs. 233.8 +/- 23.5 fmol/mg protein), nor affinity were affected by heart failure. Inner medullary receptors were exclusively of the GC-A subtype with Bmax (153.2 +/- 26.4 vs. 134

Heterogeneity of NK-2 tachykinin receptors in hamster and rabbit smooth muscles.

PubMed

Maggi, C A; Eglezos, A; Quartara, L; Patacchini, R; Giachetti, A

1992-01-23

The possible existence of NK-2 receptor subtypes in peripheral smooth muscle preparations from rabbit and hamster was investigated by studying the effect of neurokinin A, the selective NK-2 receptor agonist [beta Ala8] neurokinin A (4-10), the selective NK-2 tachykinin receptor antagonists, MEN 10,376, L 659,877 and R 396, and the pseudopeptide derivative of neurokinin A (4-10), MDL 28,564. All experiments were performed in the presence of peptidase inhibitors (captopril, bestatin and thiorphan, 1 microM each). Both neurokinin A and [beta Ala8] neurokinin A (4-10) produced concentration-dependent contractions of the rabbit isolated bronchus and hamster isolated stomach and colon, as well as enhancement of the nerve-mediated twitches of rabbit isolated vas deferens (pars prostatica). MEN 10,376, L 659,877 and R 396 antagonized the effect of the NK-2 receptor selective agonist in all four tissues under study, although marked differences in antagonist potency were evident for the three antagonists. Thus MEN 10,376 was distinctly more potent (about 100 times) in rabbit than in hamster preparations while L 659,877 and R 396 were more potent in hamster than rabbit preparations. MDL 28,564 showed a distinct agonist character in rabbit preparations while it was virtually inactive in hamster preparations, where it antagonized the effect of the NK-2 receptor selective agonist.(ABSTRACT TRUNCATED AT 250 WORDS)

Acanthamoeba culbertsoni isolated from a clinical case with intraocular dissemination: Structure and in vitro analysis of the interaction with hamster cornea and MDCK epithelial cell monolayers.

PubMed

González-Robles, Arturo; Omaña-Molina, Maritza; Salazar-Villatoro, Lizbeth; Flores-Maldonado, Catalina; Lorenzo-Morales, Jacob; Reyes-Batlle, María; Arnalich-Montiel, Francisco; Martínez-Palomo, Adolfo

2017-12-01

Acanthamoeba culbertsoni trophozoites, previously isolated from a human keratitis case with severe intraocular damage, were maintained in axenic culture. Co-incubation of amoebae with MDCK cell monolayers demonstrated an apparent preference of the amoebae to introduce themselves between the cells. The trophozoites appeared to cross the cell monolayer through the tight junctions, which resulted in decreased trans-epithelial resistance (TER) measurements. Unexpectedly, after co-incubation of amoebae with hamster corneas, we observed that the trophozoites were able to cross the different cell layers and reach the corneal stroma after only 12 h of interaction, in contrast to other Acanthamoeba species. These observations suggest that this A. culbertsoni isolate is particularly pathogenic. Further research with diverse methodologies needs to be performed to explain the unique behavior of this Acanthamoeba strain. Copyright © 2017 Elsevier Inc. All rights reserved.

After infection with Leishmania infantum, Golden Hamsters (Mesocricetus auratus) become more attractive to female sand flies (Lutzomyia longipalpis).

PubMed

Nevatte, T M; Ward, R D; Sedda, L; Hamilton, J G C

2017-07-21

In Brazil, human and canine visceral leishmaniasis is caused by infection with Leishmania infantum, a Protist parasite transmitted by blood-feeding female Lutzomyia longipalpis sand flies. The objective of this study was to determine if the odour of hamsters, infected with Le. infantum, was more attractive than the odour of the same hamsters, before they were infected. The attractiveness of odour collected from individual hamsters (n = 13), before they were infected, was compared in a longitudinal study, with the attractiveness of the odour of the same hamster in a Y-tube olfactometer bioassay, at a late stage of infection. The odour of six of the golden hamsters was significantly more attractive to 50% of the female sand flies at the end of infection compared to before infection and the odour of four of the golden hamsters was significantly more attractive to 75% of the female sand flies at the end of infection. These results strongly indicate that hamsters infected with Le. infantum become significantly more attractive to a greater proportion of female sand flies as the infection progresses.

The impact of homologous recombination repair deficiency on depleted uranium clastogenicity in Chinese hamster ovary cells: XRCC3 protects cells from chromosome aberrations, but increases chromosome fragmentation.

PubMed

Holmes, Amie L; Joyce, Kellie; Xie, Hong; Falank, Carolyne; Hinz, John M; Wise, John Pierce

2014-04-01

Depleted uranium (DU) is extensively used in both industry and military applications. The potential for civilian and military personnel exposure to DU is rising, but there are limited data on the potential health hazards of DU exposure. Previous laboratory research indicates DU is a potential carcinogen, but epidemiological studies remain inconclusive. DU is genotoxic, inducing DNA double strand breaks, chromosome damage and mutations, but the mechanisms of genotoxicity or repair pathways involved in protecting cells against DU-induced damage remain unknown. The purpose of this study was to investigate the effects of homologous recombination repair deficiency on DU-induced genotoxicity using RAD51D and XRCC3-deficient Chinese hamster ovary (CHO) cell lines. Cells deficient in XRCC3 (irs1SF) exhibited similar cytotoxicity after DU exposure compared to wild-type (AA8) and XRCC3-complemented (1SFwt8) cells, but DU induced more break-type and fusion-type lesions in XRCC3-deficient cells compared to wild-type and XRCC3-complemented cells. Surprisingly, loss of RAD51D did not affect DU-induced cytotoxicity or genotoxicity. DU induced selective X-chromosome fragmentation irrespective of RAD51D status, but loss of XRCC3 nearly eliminated fragmentation observed after DU exposure in wild-type and XRCC3-complemented cells. Thus, XRCC3, but not RAD51D, protects cells from DU-induced breaks and fusions and also plays a role in DU-induced chromosome fragmentation. Copyright © 2014 Elsevier B.V. All rights reserved.

Behavioral and autonomic thermoregulation in hamsters during microwave-induced heat exposure

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

Gordon, C.J.; Long, M.D.; Fehlner, K.S.

1984-01-01

Preferred ambient temperature (Ta) and ventilatory frequency were measured in free-moving hamsters exposed to 2450-MHz microwaves. A waveguide exposure system that permits continuous monitoring of the absorbed heat load accrued from microwave exposure was imposed with a longitudinal temperature gradient which allowed hamsters to select their preferred Ta. Ventilatory frequency was monitored remotely by analysing the rhythmic shifts in unabsorbed microwave energy passing down the waveguide. Without microwave exposure hamsters selected an average T2 of 30.2 C. This preferred Ta did not change until the rate of heat absorption (SAR) from microwave exposure exceeded approx. 2 W kg-1. In amore » separate experiment, a SAR of 2.0 W kg-1 at a Ta of 30C was shown to promote an average 0.5 C increase in colonic temperature. Hamsters maintained their ventilatory frequency at baseline levels by selecting a cooler Ta during microwave exposure. These data support previous studies suggesting that during thermal stress behavioral thermo-regulation (i.e. preferred Ta) takes prescedence over autonomic thermoregulation (i.e. ventilatory frequency). It is apparent that selecting a cooler Ta is a more efficient and/or effective than autonomic thermoregulation for dissipating a heat load accrued from microwave exposure.« less

Key role of T cell defects in age-related vulnerability to West Nile virus.

PubMed

Brien, James D; Uhrlaub, Jennifer L; Hirsch, Alec; Wiley, Clayton A; Nikolich-Zugich, Janko

2009-11-23

West Nile virus (WNV) infection causes a life-threatening meningoencephalitis that becomes increasingly more prevalent over the age of 50 and is 40-50x more prevalent in people over the age of 70, compared with adults under the age of 40. In a mouse model of age-related vulnerability to WNV, we demonstrate that death correlates with increased viral titers in the brain and that this loss of virus control with age was the result of defects in the CD4 and CD8 T cell response against WNV. Specific age-related defects in T cell responses against dominant WNV epitopes were detected at the level of cytokine and lytic granule production, each of which are essential for resistance against WNV, and in the ability to generate multifunctional anti-WNV effector T cells, which are believed to be critical for robust antiviral immunity. In contrast, at the peak of the response, old and adult T cells exhibited superimposable peptide sensitivity. Most importantly, although the adult CD4 or CD8 T cells readily protected immunodeficient mice upon adoptive transfer, old T cells of either subset were unable to provide WNV-specific protection. Consistent with a profound qualitative and quantitative defect in T cell immunity, old brains contained at least 12x fewer total effector CD8 T cells compared with adult mice at the peak of brain infection. These findings identify potential targets for immunomodulation and treatment to combat lethal WNV infection in the elderly.

Lectin histochemistry as a tool to identify apoptotic cells in the seminiferous epithelium of Syrian hamster (Mesocricetus auratus) subjected to short photoperiod.

PubMed

Seco-Rovira, V; Beltrán-Frutos, E; Ferrer, C; Sánchez-Huertas, M M; Madrid, J F; Saez, F J; Pastor, L M

2013-12-01

Lectins have been widely used to study the pattern of cellular glycoconjugates in numerous species. In the process of cellular apoptosis, it has been observed that changes occur in the membrane sugar sequences of these apoptotic cells. The aim of our work was to identify which lectins, out of an extensive battery of the same (PNA, SBA, HPA, LTA, Con-A, UEA-I, WGA, DBA, MAA, GNA, AAA, SNA), show affinity for germinal cells in apoptosis, at what stage of cell death they do so and in which germinal cell types they can be detected. For this, we studied testis sections during testicular regression in Syrian hamster (Mesocricetus auratus) subjected to short photoperiod. Several lectins showed an affinity for the glycoconjugate residues of germ cells in apoptosis: Gal β1,3-GalNAcα1, α-d-mannose, N-acetylgalactosamine and l-fucose. Furthermore, lectin specificity was observed for some specific germinal cells and in certain stages of apoptosis. It was also observed that one of these lectins (PNA) showed affinity for Sertoli cells undergoing apoptosis. Therefore, we conclude that the use of lectin histochemistry could be a very useful tool for studying apoptosis in the seminiferous epithelium because of the specificity shown towards germinal cells in pathological or experimentally induced epithelial depletion models. © 2013 Blackwell Verlag GmbH.

Induction of morphological transformation in mouse C3H/10T1/2 clone 8 cells and chromosomal damage in hamster A(T1)C1-3 cells by cancer chemotherapeutic agents.

PubMed

Benedict, W F; Banerjee, A; Gardner, A; Jones, P A

1977-07-01

Various cancer chemotherapeutic agents including alkylating agents, antimetabolites, and antibiotics or natural products were studied for their ability to produce morphological transformation in the C3H/10T1/2 clone 8 mouse cell line and chromosomal damage in the A(T1)C1-3 hamster cell line following a 24-hr exposure of each agent at different concentrations. Those drugs that were known to be carcinogenic in vivo also produced morphological transformation and chromosomal damage, whereas those agents that have not been shown to be carcinogenic in vivo produced neither transformation nor chromosomal lesions. The concentrations used for these studies were in general similar to those actually reached in the plasma of patients treated with these same drugs for malignant, as well as certain nonmalignant, conditions.

Targeted knock-in of an scFv-Fc antibody gene into the hprt locus of Chinese hamster ovary cells using CRISPR/Cas9 and CRIS-PITCh systems.

PubMed

Kawabe, Yoshinori; Komatsu, Shinya; Komatsu, Shodai; Murakami, Mai; Ito, Akira; Sakuma, Tetsushi; Nakamura, Takahiro; Yamamoto, Takashi; Kamihira, Masamichi

2018-05-01

Chinese hamster ovary (CHO) cells have been used as host cells for the production of pharmaceutical proteins. For the high and stable production of target proteins, the transgene should be integrated into a suitable genomic locus of host cells. Here, we generated knock-in CHO cells, in which transgene cassettes without a vector backbone sequence were integrated into the hprt locus of the CHO genome using clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 and CRISPR-mediated precise integration into target chromosome (CRIS-PITCh) systems. We investigated the efficiency of targeted knock-in of transgenes using these systems. As a practical example, we generated knock-in CHO cells producing an scFv-Fc antibody using the CRIS-PITCh system mediated by microhomology sequences for targeting. We found that the CRIS-PITCh system can facilitate targeted knock-in for CHO cell engineering. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Enhancement of glucose uptake in skeletal muscle L6 cells and insulin secretion in pancreatic hamster-insulinoma-transfected cells by application of non-thermal plasma jet

NASA Astrophysics Data System (ADS)

Kumar, Naresh; Kaushik, Nagendra K.; Park, Gyungsoon; Choi, Eun H.; Uhm, Han S.

2013-11-01

Type-II diabetes Mellitus is characterized by defects in insulin action on peripheral tissues, such as skeletal muscle, adipose tissue, and liver and pancreatic beta cells. Since the skeletal muscle accounts for approximately 75% of insulin-stimulated glucose-uptake in our body, impaired insulin secretion from defected beta cell plays a major role in the afflicted glucose homoeostasis. It was shown that the intracellular reactive oxygen species and nitric oxide level was increased by non-thermal-plasma treatment in ambient air. These increased intracellular reactive species may enhance glucose uptake and insulin secretion through the activation of intracellular calcium (Ca+) and cAMP production.

Pharmacological characterization of the human histamine H2 receptor stably expressed in Chinese hamster ovary cells.

PubMed Central

Leurs, R.; Smit, M. J.; Menge, W. M.; Timmerman, H.

1994-01-01

1. The gene for the human histamine H2 receptor was stably expressed in Chinese hamster ovary (CHO) cells and characterized by [125I]-iodoaminopotentidine binding studies. In addition, the coupling of the expressed receptor protein to a variety of signal transduction pathways was investigated. 2. After cotransfection of CHO cells with pCMVhumH2 and pUT626, a phleomycine-resistant clonal cell line (CHOhumH2) was isolated that expressed 565 +/- 35 fmol kg-1 protein binding sites with high affinity (0.21 +/- 0.02 nM) for the H2 antagonist, [125I]-iodoaminopotentidine. 3. Displacement studies with a variety of H2 antagonists indicated that the encoded protein was indistinguishable from the H2 receptor identified in human brain membranes and guinea-pig right atrium. The Ki-values observed in the various preparations correlated very well (r2 = 0.996-0.920). 4. Displacement studies with histamine showed that a limited fraction (32 +/- 6%) of the binding sites showed a high affinity for histamine (2 +/- 1.2 microM); the shallow displacement curves were reflected by a Hill-coefficient significantly different from unity (nH = 0.58 +/- 0.09). The addition of 100 microM Gpp(NH)p resulted in a steepening of the displacement curve (nH = 0.79 +/- 0.02) and a loss of high affinity sites for histamine. 5. Displacement studies with other agonists indicated that the recently developed specific H2 agonists, amthamine and amselamine, showed an approximately 4-5 fold higher affinity for the human H2 receptor than histamine. 6. Stimulation of CHOhumH2 cells with histamine resulted in a rapid rise of the intracellular cyclic AMP levels. After 10 min an approximately 10 fold increase in cyclic AMP could be measured.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 4 PMID:7921611

Anti-inflammatory and anti-periductal fibrosis effects of an anthocyanin complex in Opisthorchis viverrini-infected hamsters.

PubMed

Intuyod, Kitti; Priprem, Aroonsri; Limphirat, Wanwisa; Charoensuk, Lakhanawan; Pinlaor, Porntip; Pairojkul, Chawalit; Lertrat, Kamol; Pinlaor, Somchai

2014-12-01

The pharmacological activities of herbal extracts can be enhanced by complex formation. In this study, we manipulated cyanidin and delphinidin-rich extracts to form an anthocyanin complex (AC) with turmeric and evaluated activity against inflammation and periductal fibrosis in Opisthorchis viverrini-infected hamsters. The AC was prepared from anthocyanins extracted from cobs of purple waxy corn (70%), petals of blue butterfly pea (20%) and turmeric extract (10%), resulting in an enhanced free-radical scavenging capacity. Oral administration of AC (175 and 700 mg/kg body weight) every day for 1 month to O. viverrini-infected hamsters resulted in reduced inflammatory cells and periductal fibrosis. Fourier transform infrared spectroscopy and partial least square discriminant analysis suggested nucleic acid changes in the O. viverrini-infected liver samples, which were partially prevented by the AC treatment. AC reduced 8-oxodG formation, an oxidative DNA damage marker, significantly decreased levels of nitrite in the plasma and alanine aminotransferase activity and increased the ferric reducing ability of plasma. AC also decreased the expression of oxidant-related genes (NF-κB and iNOS) and increased the expression of antioxidant-related genes (CAT, SOD, and GPx). Thus, AC increases free-radical scavenging capacity, decreases inflammation, suppresses oxidative/nitrative stress, and reduces liver injury and periductal fibrosis in O. viverrini-infected hamsters.

Visual pigment coexpression in all cones of two rodents, the Siberian hamster, and the pouched mouse.

PubMed

Lukáts, Akos; Dkhissi-Benyahya, Ouria; Szepessy, Zsuzsanna; Röhlich, Pál; Vígh, Béla; Bennett, Nigel C; Cooper, Howard M; Szél, Agoston

2002-07-01

To decide whether the identical topography of short- and middle-wavelength cone photoreceptors in two species of rodents reflects the presence of both opsins in all cone cells. Double-label immunocytochemistry using antibodies directed against short-wavelength (S)-and middle- to long-wavelength (M/L)-sensitive opsin were used to determine the presence of visual pigments in cones of two species of rodents, the Siberian hamster (Phodopus sungorus) and the pouched mouse (Saccostomus campestris) from South Africa. Topographical distribution was determined from retinal whole-mounts, and the colocalization of visual pigments was examined using confocal laser scanning microscopy. Opsin colocalization was also confirmed in consecutive semithin tangential sections. The immunocytochemical results demonstrate that in both the Siberian hamster and the pouched mouse all retinal cones contain two visual pigments. No dorsoventral gradient in the differential expression of the two opsins is observed. The retina of the Siberian hamster and the pouched mouse is the first example to show a uniform coexpression of M and S cone opsins in all cones, without any topographical gradient in opsin expression. This finding makes these two species good models for the study of molecular control mechanisms in opsin coexpression in rodents, and renders them suitable as sources of dual cones for future investigations on the role and neural connections of this cone type.

Treatment of periodontal intrabony defects using autologous periodontal ligament stem cells: a randomized clinical trial.

PubMed

Chen, Fa-Ming; Gao, Li-Na; Tian, Bei-Min; Zhang, Xi-Yu; Zhang, Yong-Jie; Dong, Guang-Ying; Lu, Hong; Chu, Qing; Xu, Jie; Yu, Yang; Wu, Rui-Xin; Yin, Yuan; Shi, Songtao; Jin, Yan

2016-02-19

Periodontitis, which progressively destroys tooth-supporting structures, is one of the most widespread infectious diseases and the leading cause of tooth loss in adults. Evidence from preclinical trials and small-scale pilot clinical studies indicates that stem cells derived from periodontal ligament tissues are a promising therapy for the regeneration of lost/damaged periodontal tissue. This study assessed the safety and feasibility of using autologous periodontal ligament stem cells (PDLSCs) as an adjuvant to grafting materials in guided tissue regeneration (GTR) to treat periodontal intrabony defects. Our data provide primary clinical evidence for the efficacy of cell transplantation in regenerative dentistry. We conducted a single-center, randomized trial that used autologous PDLSCs in combination with bovine-derived bone mineral materials to treat periodontal intrabony defects. Enrolled patients were randomly assigned to either the Cell group (treatment with GTR and PDLSC sheets in combination with Bio-oss(®)) or the Control group (treatment with GTR and Bio-oss(®) without stem cells). During a 12-month follow-up study, we evaluated the frequency and extent of adverse events. For the assessment of treatment efficacy, the primary outcome was based on the magnitude of alveolar bone regeneration following the surgical procedure. A total of 30 periodontitis patients aged 18 to 65 years (48 testing teeth with periodontal intrabony defects) who satisfied our inclusion and exclusion criteria were enrolled in the study and randomly assigned to the Cell group or the Control group. A total of 21 teeth were treated in the Control group and 20 teeth were treated in the Cell group. All patients received surgery and a clinical evaluation. No clinical safety problems that could be attributed to the investigational PDLSCs were identified. Each group showed a significant increase in the alveolar bone height (decrease in the bone-defect depth) over time (p < 0.001). However

Comparison of the pathogenicity of Nipah virus isolates from Bangladesh and Malaysia in the Syrian hamster.

PubMed

DeBuysscher, Blair L; de Wit, Emmie; Munster, Vincent J; Scott, Dana; Feldmann, Heinz; Prescott, Joseph

2013-01-01

Nipah virus is a zoonotic pathogen that causes severe disease in humans. The mechanisms of pathogenesis are not well described. The first Nipah virus outbreak occurred in Malaysia, where human disease had a strong neurological component. Subsequent outbreaks have occurred in Bangladesh and India and transmission and disease processes in these outbreaks appear to be different from those of the Malaysian outbreak. Until this point, virtually all Nipah virus studies in vitro and in vivo, including vaccine and pathogenesis studies, have utilized a virus isolate from the original Malaysian outbreak (NiV-M). To investigate potential differences between NiV-M and a Nipah virus isolate from Bangladesh (NiV-B), we compared NiV-M and NiV-B infection in vitro and in vivo. In hamster kidney cells, NiV-M-infection resulted in extensive syncytia formation and cytopathic effects, whereas NiV-B-infection resulted in little to no morphological changes. In vivo, NiV-M-infected Syrian hamsters had accelerated virus replication, pathology and death when compared to NiV-B-infected animals. NiV-M infection also resulted in the activation of host immune response genes at an earlier time point. Pathogenicity was not only a result of direct effects of virus replication, but likely also had an immunopathogenic component. The differences observed between NiV-M and NiV-B pathogeneis in hamsters may relate to differences observed in human cases. Characterization of the hamster model for NiV-B infection allows for further research of the strain of Nipah virus responsible for the more recent outbreaks in humans. This model can be used to study NiV-B pathogenesis, transmission, and countermeasures that could be used to control outbreaks.

Comparison of the Pathogenicity of Nipah Virus Isolates from Bangladesh and Malaysia in the Syrian Hamster

PubMed Central

DeBuysscher, Blair L.; de Wit, Emmie; Munster, Vincent J.; Scott, Dana; Feldmann, Heinz; Prescott, Joseph

2013-01-01

Nipah virus is a zoonotic pathogen that causes severe disease in humans. The mechanisms of pathogenesis are not well described. The first Nipah virus outbreak occurred in Malaysia, where human disease had a strong neurological component. Subsequent outbreaks have occurred in Bangladesh and India and transmission and disease processes in these outbreaks appear to be different from those of the Malaysian outbreak. Until this point, virtually all Nipah virus studies in vitro and in vivo, including vaccine and pathogenesis studies, have utilized a virus isolate from the original Malaysian outbreak (NiV-M). To investigate potential differences between NiV-M and a Nipah virus isolate from Bangladesh (NiV-B), we compared NiV-M and NiV-B infection in vitro and in vivo. In hamster kidney cells, NiV-M-infection resulted in extensive syncytia formation and cytopathic effects, whereas NiV-B-infection resulted in little to no morphological changes. In vivo, NiV-M-infected Syrian hamsters had accelerated virus replication, pathology and death when compared to NiV-B-infected animals. NiV-M infection also resulted in the activation of host immune response genes at an earlier time point. Pathogenicity was not only a result of direct effects of virus replication, but likely also had an immunopathogenic component. The differences observed between NiV-M and NiV-B pathogeneis in hamsters may relate to differences observed in human cases. Characterization of the hamster model for NiV-B infection allows for further research of the strain of Nipah virus responsible for the more recent outbreaks in humans. This model can be used to study NiV-B pathogenesis, transmission, and countermeasures that could be used to control outbreaks. PMID:23342177

The use of primary rat hepatocytes to achieve metabolic activation of promutagens in the Chinese hamster ovary/hypoxanthine-guanine phosphoribosyl transferase mutational assay.

PubMed

Bermudez, E; Couch, D B; Tillery, D

1982-01-01

A method is described in which primary rat hepatocytes have been cocultured with Chinese hamster ovary (CHO) cells to provide metabolic activation of promutagens in the Chinese hamster ovary/hypoxanthine-guanine phosphoribosyl transferase (CHO/HGPRT) mutational assay. Single cell hepatocyte suspensions were prepared from male Fischer-344 rats using the in situ collagenase perfusion technique. Hepatocytes were allowed to attach for 1.5 hours in tissue culture dishes containing an approximately equal number of CHO cells in log growth. The cocultures were exposed to promutagens for up to 20 hours in serum-free medium. The survival and 6-thioguanine-resistant fraction of treated CHO cells were then determined as in the standard CHO/HGPRT assay. Aflatoxin B1 (AFB1) 7,12-dimethylbenz(a)anthracene (DMBA) and benzo(a)pyrene (B(A)P) were found to produce increases in the mutant fractions of treated CHO cells as a function of concentration. The time required for optimum expression of the mutant phenotype following exposure to DMBA and AFB1 was approximately 8 days. Primary cell-mediated mutagenesis may be useful in elucidating metabolic pathways important in the production and detoxification of genotoxic products in vivo.

In hamsters the D1 receptor antagonist SCH23390 depresses ventilation during hypoxia.

PubMed

Schlenker, Evelyn H

2008-01-02

During exposure of animals to hypoxia, brain and blood dopamine levels increase stimulating dopaminergic receptors which influence the integrated ventilatory response to low oxygen. The purpose of the present study is to test the hypothesis that in conscious hamsters, systemic antagonism of D(1) receptors would depress their breathing in air and in response to hypoxic and hypercapnic challenges. Nine male hamsters were treated with saline or 0.25 mg/kg SCH-23390 (SCH), a D(1) receptor antagonist that crosses the blood-brain barrier. Ventilation was determined using the barometric method, and oxygen consumption and CO(2) production were evaluated utilizing the flow-through method. During exposure to air, SCH decreased frequency of breathing. During exposure to hypoxia (10% oxygen in nitrogen), relative to saline, SCH-treated hamsters decreased minute ventilation by decreasing tidal volume and oxygen consumption but not CO(2) production. During exposure to hypercapnia (5% CO(2) in 95% O(2)), frequency of breathing was decreased with SCH, but there was no significant effect on minute ventilation. Relative to saline treatment body temperature was lower in SCH-treated hamsters by 0.6 degrees C. These results demonstrate that in hamsters D(1) receptors can modulate control of ventilation in air and during hypoxia and hypercapnic exposures. Whether D(1) receptors located centrally or on carotid bodies modulate these effects is not clear from this study.

Detection of microstructural defects in chalcopyrite Cu(In,Ga)Se2 solar cells by spectrally-filtered electroluminescence

NASA Astrophysics Data System (ADS)

Skvarenina, L.; Gajdos, A.; Macku, R.; Skarvada, P.

2017-12-01

The aim of this research is to detect and localize microstructural defects by using an electrically excited light emission from a forward/reverse-bias stressed pn-junction in thin-film Cu(In; Ga)Se2 solar cells with metal wrap through architecture. A different origin of the local light emission from intrinsic/extrinsic imperfections in these chalcopyrite-based solar cells can be distinguished by a spectrally-filtered electroluminescence mapping. After a light emission mapping and localization of the defects in a macro scale is performed a micro scale exploration of the solar cell surface by a scanning electron microscope which follows the particular defects obtained by an electroluminescence. In particular, these macroscopic/microscopic examinations are performed independently, then the searching of the corresponding defects in the micro scale is rather difficult due to a diffused light emission obtained from the macro scale localization. Some of the defects accompanied by a highly intense light emission very often lead to a strong local overheating. Therefore, the lock-in infrared thermography is also performed along with an electroluminescence mapping.

Effect of heavy-ion beam irradiation on the level of serum soluble interleukin-2 receptors in hamster cheek pouch carcinoma model

PubMed Central

AN, XIAOLI; LI, MINGXIN; LI, NA; LIU, BIN; ZHANG, HONG; WANG, JIZENG

2014-01-01

Soluble interleukin-2 receptor (sIL-2R) is a glycoprotein derived from α chain of interleukin 2 receptors of mononuclear as well as T-cell membranes. The aims of this study were to detect the changes of serum soluble interleukin-2 receptor (sIL-2R) levels following heavy-ion beam irradiation in the hamster model with cheek pouch carcinoma, as well as to examine the impact of immune status of the hamster cheek pouch carcinoma model using heavy-ion beam irradiation. sIL-2R serum levels were detected by radioimmunoassay (RIA) in 40 hamsters bearing cheek pouch carcinoma prior to and following exposure to heavy-ion beam irradiation, and 8 normal animals served as the control. The sIL-2R serum level in hamster cheek pouch carcinoma model was significantly increased as compared to the normal control group (P<0.05). Results showed that an increase in the irradiation dose led to a gradual decrease in the sIL-2R serum level. Additionally, a statistical significance was observed compared to the tumor group (P<0.05). In conclusion, alterations in serum sIL-2R expression have an effect on the hamsters cheek pouch carcinoma model subsequent to heavy-ion beam irradiation. An increase in the irradiation dose indicated a decreased tendency in serum sIL-2R content. Detection of serum level changes may lead to an improved understanding of heavy-ion irradiation in vivo immune status, which is crucial for clinical diagnosis and prognosis. It can also provide a sensitive indicator to help estimate the effects of heavy-ion cancer targets. PMID:24748984

Pharmacokinetics of meso-(tetrahydroxyphenyl)chlorin (m-THPC) studied by fluorescence spectroscopy on early cancer of the cheek pouch mucosa of Golden Syrian hamsters

NASA Astrophysics Data System (ADS)

Glanzmann, Thomas M.; Theumann, Jean-Francois; Braichotte, Daniel; Forrer, Martin; Wagnieres, Georges A.; van den Bergh, Hubert; Andrejevic-Blant, Snezana; Savary, Jean-Francois; Monnier, Philippe

1995-01-01

Golden Syrian hamsters are evaluated as an animal model for phototherapy of early squamous cell carcinomas of the mucosa of the upper aerodigestive tract, the esophagus and the tracheobronchial tree. Carcinomas of this type are induced on the hamster cheek pouch mucosa by the application of the carcinogen 7,12 DMBA. For phototherapeutic experiments on the animals we utilized meso- (tetrahydoxyphenyl)chlorin (mTHPC). The same drug is currently in phase I, II clinical trials for ENT patients with superficial squamous cell carcinomas. By means of light induced fluorescence (LIF) we measured in vivo the kinetics of the uptake and removal of mTHPC in the normal and tumoral cheek mucosa and in the skin. The photodynamic therapy (PDT) reaction of the tissue after excitation of the photosensitizer by laser light at 652 nm was studied. Both pharmacokinetics and PDT efficacy are compared between animal model and clinical results with special emphasis on selectivity between normal and tumoral mucosa. These first experiments show that this tumor model in the hamster cheek pouch seems to be suitable for tests of a number of PDT variables of new photosensitizers preceding their clinical application as well as for optimization of the multiple parameters of clinical phototherapy.

Distinct functional characteristics of levocabastine sensitive rat neurotensin NT2 receptor expressed in Chinese hamster ovary cells.

PubMed

Yamada, M; Yamada, M; Lombet, A; Forgez, P; Rostène, W

1998-01-01

Neurotensin has been shown to produce pharmacological effects both in brain and periphery. Several of these effects are mediated by a high-affinity neurotensin NT1 receptor. On the other hand, a low-affinity levocabastine-sensitive neurotensin NT2 receptor was molecularly cloned from rodent brain recently. In this study, in contrast to NT1 receptor, levocabastine (a histamine H1 receptor antagonist) and SR48692 (an antagonist for NT1 receptor) strongly stimulated intracellular Ca2+ mobilization in transfected Chinese hamster ovary cells expressing rat NT2 receptor, thus acting as potent NT2 receptor. Furthermore, despite of their affinities for NT2 receptor, the Ca2+ responses to potent NT1 agonists, neurotensin or JMV449 ([Lys8-(CH2NH)-Lys9]Pro-Tyr-Ile-Leu, a peptidase resistant analogue of neurotensin) were much smaller than that observed with SR48692. These findings suggest that NT1 and NT2 receptors present distinct functional characteristics and that SR48692 may act as a potent agonist for NT2 receptor.

Effect of thermal-convection-induced defects on the performance of perovskite solar cells

NASA Astrophysics Data System (ADS)

Ye, Fei; Xie, Fengxian; Yin, Maoshu; He, Jinjin; Wang, Yanbo; Tang, Wentao; Chen, Han; Yang, Xudong; Han, Liyuan

2017-07-01

Thermal-convection-induced defects can cause huge loss in the power conversion efficiency of solution-processed perovskite solar cells. We investigated two types of convection in perovskite solution during the formation of perovskite films. By balancing the convection via special configurations of surface tension and boiling point in mixed γ-butyrolactone (GBL) and dimethylsulfoxide (DMSO), we removed microscopic defects such as rings, bumps, and crevices. The deposited perovskite films were smooth and dense, which enabled a high power conversion efficiency of 17.7% in a 1 cm2 cell area. We believe that the present strategy for controlling the convection can be helpful in improving the perovskite film quality for solvent-rich scalable solution processes of solar cells such as doctor blading, soft-cover deposition, printing, and slot-die coating.

Monosodium glutamate-induced arcuate nucleus damage affects both natural torpor and 2DG-induced torpor-like hypothermia in Siberian hamsters.

PubMed

Pelz, Kimberly M; Routman, David; Driscoll, Joseph R; Kriegsfeld, Lance J; Dark, John

2008-01-01

Siberian hamsters (Phodopus sungorus) have the ability to express daily torpor and decrease their body temperature to approximately 15 degrees C, providing a significant savings in energy expenditure. Daily torpor in hamsters is cued by winterlike photoperiods and occurs coincident with the annual nadirs in body fat reserves and chronic leptin concentrations. To better understand the neural mechanisms underlying torpor, Siberian hamster pups were postnatally treated with saline or MSG to ablate arcuate nucleus neurons that likely possess leptin receptors. Body temperature was studied telemetrically in cold-acclimated (10 degrees C) male and female hamsters moved to a winterlike photoperiod (10:14-h light-dark cycle) (experiments 1 and 2) or that remained in a summerlike photoperiod (14:10-h light-dark cycle) (experiment 3). In experiment 1, even though other photoperiodic responses persisted, MSG-induced arcuate nucleus ablations prevented the photoperiod-dependent torpor observed in saline-treated Siberian hamsters. MSG-treated hamsters tended to possess greater fat reserves. To determine whether reductions in body fat would increase frequency of photoperiod-induced torpor after MSG treatment, hamsters underwent 2 wk of food restriction (70% of ad libitum) in experiment 2. Although food restriction did increase the frequency of torpor in both MSG- and saline-treated hamsters, it failed to normalize the proportion of MSG-treated hamsters undergoing photoperiod-dependent torpor. In experiment 3, postnatal MSG treatments reduced the proportion of hamsters entering 2DG-induced torpor-like hypothermia by approximately 50% compared with saline-treated hamsters (38 vs. 72%). In those MSG-treated hamsters that did become hypothermic, their minimum temperature during hypothermia was significantly greater than comparable saline-treated hamsters. We conclude that 1) arcuate nucleus mechanisms mediate photoperiod-induced torpor, 2) food-restriction-induced torpor may also be

Structural Defects in Donor-Acceptor Blends: Influence on the Performance of Organic Solar Cells

NASA Astrophysics Data System (ADS)

Sergeeva, Natalia; Ullbrich, Sascha; Hofacker, Andreas; Koerner, Christian; Leo, Karl

2018-02-01

Defects play an important role in the performance of organic solar cells. The investigation of trap states and their origin can provide ways to further improve their performance. Here, we investigate defects in a system composed of the small-molecule oligothiophene derivative DCV5T-Me blended with C60 , which shows power conversion efficiencies above 8% when used in a solar cell. From a reconstruction of the density of trap states by impedance spectroscopy, we obtain a Gaussian distribution of trap states with Et=470 meV below the electron transport level, Nt=8 ×1014 cm-3 , and σt=41 meV . From Voc vs illumination intensity and open-circuit corrected charge carrier extraction measurements, we find that these defects lead to trap-assisted recombination. Moreover, drift-diffusion simulations show that the trap states decrease the fill factor by 10%. By conducting degradation measurements and varying the blend ratio, we find that the observed trap states are structural defects in the C60 phase due to the distortion of the natural morphology induced by the mixing.

Photoperiodic adjustments in immune function protect Siberian hamsters from lethal endotoxemia.

PubMed

Prendergast, Brian J; Hotchkiss, Andrew K; Bilbo, Staci D; Kinsey, Steven G; Nelson, Randy J

2003-02-01

Seasonal changes in day length enhance or suppress components of immune function in individuals of several mammalian species. Siberian hamsters (Phodopus sungorus) exhibit multiple changes in neuroendocrine, reproductive, and immune function after exposure to short days. The manner in which these changes are integrated into the host response to pathogens is not well understood. The present experiments tested the hypothesis that short-day changes in immune function alter the pathogenesis of septic shock and survival after challenge with endotoxin. Male and female Siberian hamsters raised in long-day photoperiods were transferred as adults to short days or remained in their natal photoperiod. Six to 8 weeks later, hamsters were injected i.p. with 0, 1, 2.5, 10, 25, or 50 mg/kg bacterial lipopolysaccharide (LPS) (the biologically active constituent of endotoxin), and survival was monitored for 96 h. Short days significantly improved survival of male hamsters treated with 10 or 25 mg/kg LPS and improved survival in females treated with 50 mg/kg LPS. Transfer from long to short days shifted the LD50 in males by approximately 90%, from 5.3 to 9.9 mg/kg, and in females from 11.1 to 15.0 mg/kg (+35%). Long-day females were more resistant than were males to lethal endotoxemia. In vitro production of the proinflammatory cytokine TNFalpha in response to LPS stimulation was significantly lower in macrophages extracted from short-day relative to long-day hamsters, as were circulating concentrations of TNFalpha in vivo after i.p. administration of LPS, suggesting that diminished cytokine responses to LPS in short days may mitigate the lethality of endotoxemia. Adaptation to short days induces changes in immune parameters that affect survival in the face of immune challenges.

Effects of thalidomide on DMBA-induced oral carcinogenesis in hamster with respect to angiogenesis.

PubMed

Yang, Y; Ge, J-P; Zhou, Z-T

2009-05-01

Thalidomide has been shown to have anti-angiogenic effects in pre-clinical models as well as a significant antitumor effect in hematologic tumors. However, the effects of thalidomide on oral pre-malignant lesions and oral carcinogenesis remain unexplored. The authors aimed to investigate the chemopreventive effect of thalidomide on 7,12-dimethylbenz[a]anthracene (DMBA)-induced oral carcinogenesis in hamsters with respect to angiogenesis. Seventy male Syrian golden hamsters were randomly divided into five groups, with two of 20 and three of 10. DMBA solution (0.5% in acetone) was applied topically to the left cheek pouch of male Syrian golden hamsters in group A and B, while animals in group C were painted with acetone, three times a week for 6 weeks. For the next 18 weeks, animals in group B and D received thalidomide daily (40 mg/kg body weight/day) by gavage, animals in group A and C received same volume of saline. Animals in group E received no treatment and served as blank control. At the end of the experiment, animals were killed and tissue samples were collected for examinations. Thalidomide significantly decreased the squamous cell carcinoma (SCC) incidence from 57.9 to 11.8%; angiogenesis was inhibited in dysplasia and SCC. The gene expression of vascular endothelium growth factor and tumor necrosis factor (TNF)-alpha was downregulated. Thalidomide has inhibitory effect against the malignant transformation of oral pre-cancerous lesion and angiogenesis during oral carcinogenesis. Such inhibition is related to its modulation of TNF-alpha.

Effect of mangrove black tea extract from Ceriops decandra (Griff.) on hematology and biochemical changes in dimethyl benz[a]anthracene-induced hamster buccal pouch carcinogenesis.

PubMed

Sithranga Boopathy, N; Kathiresan, K; Jeon, Y J

2011-09-01

Effect of the black tea extracted from a mangrove plant species, Ceriops decandra (Griff.) was studied on dimethyl benz[a]anthracene (DMBA)-induced changes in blood hematology and plasma non-enzymatic antioxidants in male hamsters. Hamsters were painted with 0.5% solution of DMBA in liquid paraffin on the right buccal pouch three times in a week up to 14 weeks. Each application treated with 0.4mg of DMBA. The mangrove black tea extract (MBTE) was administrated orally with 5mgkg(-1) twice a day and then with DMBA on alternate days. Results showed that the DMBA caused a significant (P<0.05) decline in the levels of reduced glutathione (GSH), vitamin-C, -E, red blood cells, hemoglobin, mean corpuscular volume and hematocrit; and increase in the levels of WBC, platelets, lymphocytes and neutrophils. The MBTE prevented the DMBA-induced adverse changes significantly in blood and biochemical parameters of the male hamsters. This work concluded that the black tea extracted from the coastal mangrove species C. decandra prevented the DMBA-induced buccal pouch carcinogenesis in hamsters. Copyright © 2011 Elsevier B.V. All rights reserved.

Interlaboratory studies with the Chinese hamster V79 cell metabolic cooperation assay to detect tumor-promoting agents

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

Bohrman, J.S.; Burg, J.R.; Elmore, E.

1988-01-01

Three laboratories participated in an interlaboratory study to evaluate the usefulness of the Chinese hamster V79 cell metabolic cooperation assay to predict the tumor-promoting activity of selected chemical. Twenty-three chemicals of different chemical structures (phorbol esters, barbiturates, phenols, artificial sweeteners, alkanes, and peroxides) were chosen for testing based on in vivo promotion activities, as reported in the literature. Assay protocols and materials were standardized, and the chemicals were coded to facilitate unbiased evaluation. A chemical was tested only once in each laboratory, with one of the three laboratories testing only 15 out of 23 chemicals. Dunnett's test was used formore » statistical analysis. Chemicals were scored as positive (at least two concentration levels statistically different than control), equivocal (only one concentration statistically different), or negative. For 15 chemicals tested in all three laboratories, there was complete agreement among the laboratories for nine chemicals. For the 23 chemicals tested in only two laboratories, there was agreement on 16 chemicals. With the exception of the peroxides and alkanes, the metabolic cooperation data were in general agreement with in vivo data. However, an overall evaluation of the V79 cell system for predicting in vivo promotion activity was difficult because of the organ specificity of certain chemicals and/or the limited number of adequately tested nonpromoting chemicals.« less

CHARACTERIZATION OF VIRULENCE OF Leptospira ISOLATES IN A HAMSTER MODEL

PubMed Central

Silva, Éverton F.; Santos, Cleiton S.; Athanazio, Daniel A.; Seyffert, Núbia; Seixas, Fabiana K.; Cerqueira, Gustavo M.; Fagundes, Michel Q.; Brod, Claudiomar S.; Reis, Mitermayer G.; Dellagostin, Odir A.; Ko, Albert I.

2008-01-01

Effort has been made to identify protective antigens in order to develop a recombinant vaccine against leptospirosis. Several attempts failed to conclusively demonstrate efficacy of vaccine candidates due to the lack of an appropriate model of lethal leptospirosis. The purposes of our study were: (i) to test the virulence of leptospiral isolates from Brazil, which are representative of important serogroups that cause disease in humans and animals; and (ii) to standardize the lethal dose 50% (LD50) for each of the virulent strains using a hamster (Mesocricetus auratus) model. Five of seven Brazilian isolates induced lethality in a hamster model, with inocula lower than 200 leptospires. Histopathological examination of infected animals showed typical lesions found in both natural and experimental leptospirosis. Results described here demonstrated the potential use of Brazilian isolates as highly virulent strains in challenge experiments using hamster as an appropriate animal model for leptospirosis. Furthermore these strains may be useful in heterologous challenge studies which aim to evaluate cross-protective responses induced by subunit vaccine candidates. PMID:18547690

A major defect in mast cell effector functions in CRACM1-/- mice

PubMed Central

Vig, Monika; Dehaven, Wayne I; Bird, Gary S; Billingsley, James M; Wang, Huiyun; Rao, Patricia E; Hutchings, Amy B; Jouvin, Marie-Hélène; Putney, James W; Kinet, Jean-Pierre

2008-01-01

CRACM1 (Orai1) constitutes the pore subunit of CRAC channels that are crucial for many physiological processes 1-6. A point mutation in CRACM1 has been associated with SCID disease in humans 2. We have generated CRACM1 deficient mice using gene trap, where β-galactosidase (LacZ) activity identifies CRACM1 expression in tissues. We show here that the homozygous CRACM1 deficient mice are considerably smaller in size and are grossly defective in mast cell degranulation and cytokine secretion. FcεRI-mediated in vivo allergic reactions were also inhibited in CRACM1-/- mice. Other tissues expressing truncated CRACM1-LacZ fusion protein include skeletal muscles, kidney and regions in the brain and heart. Surprisingly, no CRACM1 expression was seen in the lymphoid regions of thymus. Accordingly, we found no defect in T cell development. Thus, our data reveal novel crucial roles for CRAC channels including a putative role in excitable cells. PMID:18059270

Expression of cystic fibrosis transmembrane conductance regulator corrects defective chloride channel regulation in cystic fibrosis airway epithelial cells

NASA Astrophysics Data System (ADS)

Rich, Devra P.; Anderson, Matthew P.; Gregory, Richard J.; Cheng, Seng H.; Paul, Sucharita; Jefferson, Douglas M.; McCann, John D.; Klinger, Katherine W.; Smith, Alan E.; Welsh, Michael J.

1990-09-01

The cystic fibrosis transmembrane conductance regulator (CFTR) was expressed in cultured cystic fibrosis airway epithelial cells and Cl- channel activation assessed in single cells using a fluorescence microscopic assay and the patch-clamp technique. Expression of CFTR, but not of a mutant form of CFTR (ΔF508), corrected the Cl- channel defect. Correction of the phenotypic defect demonstrates a causal relationship between mutations in the CFTR gene and defective Cl- transport which is the hallmark of the disease.

USC-087 protects Syrian hamsters against lethal challenge with human species C adenoviruses.

PubMed

Toth, Karoly; Spencer, Jacqueline F; Ying, Baoling; Tollefson, Ann E; Hartline, Caroll B; Richard, Eric T; Fan, Jiajun; Lyu, Jinglei; Kashemirov, Boris A; Harteg, Cheryl; Reyna, Dawn; Lipka, Elke; Prichard, Mark N; McKenna, Charles E; Wold, William S M

2018-05-01

Human adenoviruses (AdV) cause generally mild infections of the respiratory and GI tracts as well as some other tissues. However, AdV can cause serious infection in severely immunosuppressed individuals, especially pediatric patients undergoing allogeneic hematopoietic stem cell transplantation, where mortality rates are up to 80% with disseminated disease. Despite the seriousness of AdV disease, there are no drugs approved specifically to treat AdV infections. We report here that USC-087, an N-alkyl tyrosinamide phosphonate ester prodrug of HPMPA, the adenine analog of cidofovir, is highly effective against multiple AdV types in cell culture. USC-087 is also effective against AdV-C6 in our immunosuppressed permissive Syrian hamster model. In this model, hamsters are immunosuppressed by treatment with high dose cyclophosphamide. Injection of AdV-C6 (or AdV-C5) intravenously leads to a disseminated infection that resembles the disease seen in humans, including death. We have tested the efficacy of orally-administered USC-087 against the median lethal dose of intravenously administered AdV-C6. USC-087 completely prevented or significantly decreased mortality when administered up to 4 days post challenge. USC-087 also prevented or significantly decreased liver damage caused by AdV-C6 infection, and suppressed virus replication even when administered 4 days post challenge. These results imply that USC-087 is a promising candidate for drug development against HAdV infections. Copyright © 2018 Elsevier B.V. All rights reserved.

IN VITRO CULTURE OF POSTIMPLANTATION HAMSTER EMBRYOS

EPA Science Inventory

In vitro culture of intact rat and mouse embryos has been described extensively, but information on the culture of other species is sparse. The present study examined some culture requirements of early somite stage hamster embryos and assessed the embryotoxic effects of sodium sa...

Neural mechanisms controlling seasonal reproduction: principles derived from the sheep model and its comparison with hamsters.

PubMed

Weems, Peyton W; Goodman, Robert L; Lehman, Michael N

2015-04-01

Seasonal reproduction is a common adaptive strategy among mammals that allows for breeding to occur at times of the year when it is most advantageous for the subsequent survival and growth of offspring. A major mechanism responsible for seasonal reproduction is a striking increase in the responsiveness of gonadotropin-releasing hormone (GnRH) neurons to the negative feedback effects of estradiol. The neural and neuroendocrine circuitry responsible for mammalian seasonal reproduction has been primarily studied in three animal models: the sheep, and two species of hamsters. In this review, we first describe the afferent signals, neural circuitry and transmitters/peptides responsible for seasonal reproductive transitions in sheep, and then compare these mechanisms with those derived from studies in hamsters. The results suggest common principles as well as differences in the role of specific brain nuclei and neuropeptides, including that of kisspeptin cells of the hypothalamic arcuate nucleus, in regulating seasonal reproduction among mammals. Copyright © 2014 Elsevier Inc. All rights reserved.

Immunosuppression Enhances Oncolytic Adenovirus Replication and Antitumor Efficacy in the Syrian Hamster Model

PubMed Central

Thomas, Maria A; Spencer, Jacqueline F; Toth, Karoly; Sagartz, John E; Phillips, Nancy J; Wold, William SM

2012-01-01

We recently described an immunocompetent Syrian hamster model for oncolytic adenoviruses (Ads) that permits virus replication in tumor cells as well as some normal tissues. This model allows exploration of interactions between the virus, tumor, normal organs, and host immune system that could not be examined in the immunodeficient or nonpermissive animal models previously used in the oncolytic Ad field. Here we asked whether the immune response to oncolytic Ad enhances or limits antitumor efficacy. We first determined that cyclophosphamide (CP) is a potent immunosuppressive agent in the Syrian hamster and that CP alone had no effect on tumor growth. Importantly, we found that the antitumor efficacy of oncolytic Ads was significantly enhanced in immunosuppressed animals. In animals that received virus therapy plus immunosuppression, significant differences were observed in tumor histology, and in many cases little viable tumor remained. Notably, we also determined that immunosuppression allowed intratumoral virus levels to remain elevated for prolonged periods. Although favorable tumor responses can be achieved in immunocompetent animals, the rate of virus clearance from the tumor may lead to varied antitumor efficacy. Immunosuppression, therefore, allows sustained Ad replication and oncolysis, which leads to substantially improved suppression of tumor growth. PMID:18665155

Defective IL-10 signaling in hyper-IgE syndrome results in impaired generation of tolerogenic dendritic cells and induced regulatory T cells

PubMed Central

Saito, Masako; Nagasawa, Masayuki; Takada, Hidetoshi; Hara, Toshiro; Tsuchiya, Shigeru; Agematsu, Kazunaga; Yamada, Masafumi; Kawamura, Nobuaki; Ariga, Tadashi; Tsuge, Ikuya; Nonoyama, Shigeaki; Karasuyama, Hajime

2011-01-01

Hyper-IgE syndrome (HIES) is a primary immunodeficiency characterized by recurrent staphylococcal infections and atopic dermatitis associated with elevated serum IgE levels. Although defective differentiation of IL-17–producing CD4+ T cells (Th17) partly accounts for the susceptibility to staphylococcal skin abscesses and pneumonia, the pathogenesis of atopic manifestations in HIES still remains an enigma. In this study, we examined the differentiation and function of Th1, Th2, regulatory T cells (Treg cells), and dendritic cells (DCs) in HIES patients carrying either STAT3 or TYK2 mutations. Although the in vitro differentiation of Th1 and Th2 cells and the number and function of Treg cells in the peripheral blood were normal in HIES patients with STAT3 mutations, primary and monocyte-derived DCs showed defective responses to IL-10 and thus failed to become tolerogenic. When treated with IL-10, patient DCs showed impaired up-regulation of inhibitory molecules on their surface, including PD-L1 and ILT-4, compared with control DCs. Moreover, IL-10–treated DCs from patients displayed impaired ability to induce the differentiation of naive CD4+ T cells to FOXP3+ induced Treg cells (iTreg cells). These results suggest that the defective generation of IL-10–induced tolerogenic DCs and iTreg cells may contribute to inflammatory changes in HIES. PMID:21300911

Defects and annealing studies in 1-Me electron irradiated (AlGa)As-GaAs solar cells

NASA Technical Reports Server (NTRS)

Li, S. S.; Wang, W. L.; Loo, R. Y.; Rahilly, W. P.

1982-01-01

The deep-level defects and recombination mechanisms in the one-MeV electron irradiated (AlGa)As-GaAs solar cells under various irradiation and annealing conditions are discussed. Deep-level transient spectroscopy (DLTS) and capacitance-voltage (CV) techniques were used to determine the defect and recombination parameters such as energy levels and defect density, carrier capture cross sections and lifetimes for both electron and hole traps as well as hole diffusion lengths in these electron irradiated GaAs solar cells. GaAs solar cells used in this study were prepared by the infinite solution melt liquid phase epitaxial (LPE) technique at Hughes Research Lab., with (Al0.9Ga0.1)-As window layer, Be-diffused p-GaAs layer on Sn-doped n-GaAs or undoped n-GaAs active layer grown on n(+)-GaAs substrate. Mesa structure with area of 5.86x1000 sq cm was fabricated. Three different irradiation and annealing experiments were performed on these solar cells.

Transmission of chronic wasting disease identifies a prion strain causing cachexia and heart infection in hamsters.

PubMed

Bessen, Richard A; Robinson, Cameron J; Seelig, Davis M; Watschke, Christopher P; Lowe, Diana; Shearin, Harold; Martinka, Scott; Babcock, Alex M

2011-01-01

Chronic wasting disease (CWD) is an emerging prion disease of free-ranging and captive cervids in North America. In this study we established a rodent model for CWD in Syrian golden hamsters that resemble key features of the disease in cervids including cachexia and infection of cardiac muscle. Following one to three serial passages of CWD from white-tailed deer into transgenic mice expressing the hamster prion protein gene, CWD was subsequently passaged into Syrian golden hamsters. In one passage line there were preclinical changes in locomotor activity and a loss of body mass prior to onset of subtle neurological symptoms around 340 days. The clinical symptoms included a prominent wasting disease, similar to cachexia, with a prolonged duration. Other features of CWD in hamsters that were similar to cervid CWD included the brain distribution of the disease-specific isoform of the prion protein, PrP(Sc), prion infection of the central and peripheral neuroendocrine system, and PrP(Sc) deposition in cardiac muscle. There was also prominent PrP(Sc) deposition in the nasal mucosa on the edge of the olfactory sensory epithelium with the lumen of the nasal airway that could have implications for CWD shedding into nasal secretions and disease transmission. Since the mechanism of wasting disease in prion diseases is unknown this hamster CWD model could provide a means to investigate the physiological basis of cachexia, which we propose is due to a prion-induced endocrinopathy. This prion disease phenotype has not been described in hamsters and we designate it as the 'wasting' or WST strain of hamster CWD.

Suppression of AKT phosphorylation restores rapamycin-based synthetic lethality in SMAD4-defective pancreatic cancer cells.

PubMed

Le Gendre, Onica; Sookdeo, Ayisha; Duliepre, Stephie-Anne; Utter, Matthew; Frias, Maria; Foster, David A

2013-05-01

mTOR has been implicated in survival signals for many human cancers. Rapamycin and TGF-β synergistically induce G1 cell-cycle arrest in several cell lines with intact TGF-β signaling pathway, which protects cells from the apoptotic effects of rapamycin during S-phase of the cell cycle. Thus, rapamycin is cytostatic in the presence of serum/TGF-β and cytotoxic in the absence of serum. However, if TGF-β signaling is defective, rapamycin induced apoptosis in both the presence and absence of serum/TGF-β in colon and breast cancer cell lines. Because genetic dysregulation of TGF-β signaling is commonly observed in pancreatic cancers-with defects in the Smad4 gene being most prevalent, we hypothesized that pancreatic cancers would display a synthetic lethality to rapamycin in the presence of serum/TGF-β. We report here that Smad4-deficient pancreatic cancer cells are killed by rapamycin in the absence of serum; however, in the presence of serum, we did not observe the predicted synthetic lethality with rapamycin. Rapamycin also induced elevated phosphorylation of the survival kinase Akt at Ser473. Suppression of rapamycin-induced Akt phosphorylation restored rapamycin sensitivity in Smad4-null, but not Smad4 wild-type pancreatic cancer cells. This study shows that the synthetic lethality to rapamycin in pancreatic cancers with defective TGF-β signaling is masked by rapamycin-induced increases in Akt phosphorylation. The implication is that a combination of approaches that suppress both Akt phosphorylation and mTOR could be effective in targeting pancreatic cancers with defective TGF-β signaling. ©2013 AACR.

Success of Maxillary Alveolar Defect Repair in Rats Using Osteoblast-Differentiated Human Deciduous Dental Pulp Stem Cells.

PubMed

Jahanbin, Arezoo; Rashed, Roozbeh; Alamdari, Daryoush Hamidi; Koohestanian, Niloufar; Ezzati, Atefeh; Kazemian, Mojgan; Saghafi, Shadi; Raisolsadat, Mohammad Ali

2016-04-01

The use of cell-based therapies represents one of the most advanced methods for enhancing the regenerative response in craniofacial abnormalities. The main aim of this study was to evaluate the regenerative potential of human dental pulp stem cells, isolated from deciduous teeth, for reconstructing maxillary alveolar defects in Wistar rats. Human deciduous dental pulp stem cells were isolated and stimulated to differentiate into osteoblasts in culture media. Maxillary alveolar defects were created in 60 Wistar rats by a surgical procedure. Then, on the basis of the type of graft used to repair the bone defect, the rats were divided into 6 equal groups: groups 1 and 2, transplantation of iliac bone graft; groups 3 and 4, transplantation of stem cells derived from deciduous dental pulp in addition to collagen matrix; groups 5 and 6, transplantation of just collagen matrix. Then, fetal bone formation, granulation tissue, fibrous tissue, and inflammatory tissue were evaluated by hematoxylin-eosin staining at 1 month (groups 1, 3, and 5) and 2 months (groups 2, 4, and 6) after surgery, and data were analyzed and compared using the Fisher exact test. Maximum fetal bone formation occurred in group 2, in which iliac bone graft was inserted into the defect area for 2 months; there also were significant differences among the groups for bone formation (P = .009). In the 1-month groups, there were no significant differences between the control and stem cell-plus-scaffold groups. There were significant differences between the 2-month groups for fetal bone formation only between the control and scaffold groups (P = .026). The study showed that human dental pulp stem cells are an additional cell resource for repairing maxillary alveolar defects in rats and constitute a promising model for reconstruction of human maxillary alveolar defects in patients with cleft lip and palate. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc

Human RHOH deficiency causes T cell defects and susceptibility to EV-HPV infections.

PubMed

Crequer, Amandine; Troeger, Anja; Patin, Etienne; Ma, Cindy S; Picard, Capucine; Pedergnana, Vincent; Fieschi, Claire; Lim, Annick; Abhyankar, Avinash; Gineau, Laure; Mueller-Fleckenstein, Ingrid; Schmidt, Monika; Taieb, Alain; Krueger, James; Abel, Laurent; Tangye, Stuart G; Orth, Gérard; Williams, David A; Casanova, Jean-Laurent; Jouanguy, Emmanuelle

2012-09-01

Epidermodysplasia verruciformis (EV) is a rare genetic disorder characterized by increased susceptibility to specific human papillomaviruses, the betapapillomaviruses. These EV-HPVs cause warts and increase the risk of skin carcinomas in otherwise healthy individuals. Inactivating mutations in epidermodysplasia verruciformis 1 (EVER1) or EVER2 have been identified in most, but not all, patients with autosomal recessive EV. We found that 2 young adult siblings presenting with T cell deficiency and various infectious diseases, including persistent EV-HPV infections, were homozygous for a mutation creating a stop codon in the ras homolog gene family member H (RHOH) gene. RHOH encodes an atypical Rho GTPase expressed predominantly in hematopoietic cells. Patients' circulating T cells contained predominantly effector memory T cells, which displayed impaired TCR signaling. Additionally, very few circulating T cells expressed the β7 integrin subunit, which homes T cells to specific tissues. Similarly, Rhoh-null mice exhibited a severe overall T cell defect and abnormally small numbers of circulating β7-positive cells. Expression of the WT, but not of the mutated RHOH, allele in Rhoh-/- hematopoietic stem cells corrected the T cell lymphopenia in mice after bone marrow transplantation. We conclude that RHOH deficiency leads to T cell defects and persistent EV-HPV infections, suggesting that T cells play a role in the pathogenesis of chronic EV-HPV infections.

Effect of Antiviral Agents in Equine Abortion Virus-Infected Hamsters1

PubMed Central

Lieberman, Melvin; Pascale, Andrea; Schafer, Thomas W.; Came, Paul E.

1972-01-01