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Sample records for male siberian hamsters

  1. Photoperiodic Influences on Ultradian Rhythms of Male Siberian Hamsters

    PubMed Central

    Prendergast, Brian J.; Zucker, Irving

    2012-01-01

    Seasonal changes in mammalian physiology and behavior are proximately controlled by the annual variation in day length. Long summer and short winter day lengths markedly alter the amplitude of endogenous circadian rhythms and may affect ultradian oscillations, but the threshold photoperiods for inducing these changes are not known. We assessed the effects of short and intermediate day lengths and changes in reproductive physiology on circadian and ultradian rhythms of locomotor activity in Siberian hamsters. Males were maintained in a long photoperiod from birth (15 h light/day; 15 L) and transferred in adulthood to 1 of 7 experimental photoperiods ranging from 14 L to 9 L. Decreases in circadian rhythm (CR) robustness, mesor and amplitude were evident in photoperiods ≤14 L, as were delays in the timing of CR acrophase and expansion of nocturnal activity duration. Nocturnal ultradian rhythms (URs) were comparably prevalent in all day lengths, but 15 L markedly inhibited the expression of light-phase URs. The period (τ’), amplitude and complexity of URs increased in day lengths ≤13 L. Among hamsters that failed to undergo gonadal regression in short day lengths (nonresponders), τ’ of the dark-phase UR was longer than in photoresponsive hamsters; in 13 L the incidence and amplitude of light-phase URs were greater in hamsters that did not undergo testicular regression. Day lengths as long as 14 L were sufficient to trigger changes in the waveform of CRs without affecting UR waveform. The transition from a long- to a short-day ultradian phenotype occurred for most UR components at day lengths of 12 L–13 L, thereby establishing different thresholds for CR and UR responses to day length. At the UR-threshold photoperiod of 13 L, differences in gonadal status were largely without effect on most UR parameters. PMID:22848579

  2. Glucose and insulin modulate sickness responses in male Siberian hamsters.

    PubMed

    Carlton, Elizabeth D; Demas, Gregory E

    2017-02-01

    Mounting a sickness response is an energetically expensive task and requires precise balancing of energy allocation to ensure pathogen clearance while avoiding compromising energy reserves. Sickness intensity has previously been shown to be modulated by food restriction, body mass, and hormonal signals of energy. In the current study, we tested the hypothesis that sickness intensity is modulated by glucose availability and an endocrine signal of glucose availability, insulin. We utilized male Siberian hamsters (Phodopus sungorus) and predicted that pharmacological induction of glucoprivation with 2-deoxy-d-glucose (2-DG), a non-metabolizable glucose analog that disrupts glycolysis, would attenuate energetically expensive sickness symptoms. Alternatively, we predicted that treatment of animals with insulin would enhance energetically expensive sickness symptoms, as insulin would act as a signal of increased glucose availability. Upon experimental treatment with lipopolysaccharide (LPS), we found that glucose deprivation resulted in increased sickness-induced hypothermia as compared to control- and insulin-treated animals; however, it did not have any effects on sickness-induced anorexia or body mass loss. Insulin treatment resulted in an unexpectedly exaggerated sickness response in animals of lesser body masses; however, in animals of greater body masses, insulin actually attenuated sickness-induced body mass loss and had no effects on hypothermia or anorexia. The effects of insulin on sickness severity may be modulated by sensitivity to sickness-induced hypoglycemia. Collectively, these results demonstrate that both glucose availability and signals of glucose availability can modulate the intensity of energetically expensive sickness symptoms, but their effects differ among different sickness symptoms and are sensitive to energetic context. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Photoperiod and aggression induce changes in ventral gland compounds exclusively in male Siberian hamsters.

    PubMed

    Rendon, Nikki M; Soini, Helena A; Scotti, Melissa-Ann L; Weigel, Ellen R; Novotny, Milos V; Demas, Gregory E

    2016-05-01

    Chemical communication is a critical component of social behavior as it facilitates social encounters, allows for evaluation of the social partner, defines territories and resources, and advertises information such as sex and physiological state of an animal. Odors provide a key source of information about the social environment to rodents; however, studies identifying chemical compounds have thus far focused primarily on few species, particularly the house mouse. Moreover, considerably less attention has been focused on how environmental factors, reproductive phenotype, and behavioral context alter these compounds outside of reproduction. We examined the effects of photoperiod, sex, and social context on chemical communication in the seasonally breeding Siberian hamster. We sampled ventral gland secretions in both male and female hamsters before and after an aggressive encounter and identified changes in a range of volatile compounds. Next, we investigated how photoperiod, reproductive phenotype, and aggression altered ventral gland volatile compound composition across the sexes. Males exhibited a more diverse chemical composition, more sex-specific volatiles, and showed higher levels of excretion compared to females. Individual volatiles were also differentially excreted across photoperiod and reproductive phenotype, as well as differentially altered in response to an aggressive encounter. Female volatile compound composition, in contrast, did not differ across photoperiods or in response to aggression. Collectively, these data contribute to a greater understanding of context-dependent changes in chemical communication in a seasonally breeding rodent. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Somatostatin Agonist Pasireotide Promotes a Physiological State Resembling Short-Day Acclimation in the Photoperiodic Male Siberian Hamster (Phodopus sungorus).

    PubMed

    Dumbell, R A; Scherbarth, F; Diedrich, V; Schmid, H A; Steinlechner, S; Barrett, P

    2015-07-01

    The timing of growth in seasonal mammals is inextricably linked to food availability. This is exemplified in the Siberian hamster (Phodopus sungorus), which uses the annual cycle of photoperiod to optimally programme energy expenditure in anticipation of seasonal fluctuations in food resources. During the autumn, energy expenditure is progressively minimised by physiological adaptations, including a 30% reduction in body mass, comprising a reduction in both fat and lean tissues. However, the mechanistic basis of this adaptation is still unexplained. We hypothesised that growth hormone (GH) was a likely candidate to underpin these reversible changes in body mass. Administration of pasireotide, a long-acting somatostatin receptor agonist developed for the treatment of acromegaly, to male hamsters under a long-day (LD) photoperiod produced a body weight loss. This comprised a reduction in lean and fat mass, including kidneys, testes and brown adipose tissue, typically found in short-day (SD) housed hamsters. Furthermore, when administered to hamsters switched from SD to LD, pasireotide retarded the body weight increase compared to vehicle-treated hamsters. Pasireotide did not alter photoperiod-mediated changes in hypothalamic energy balance gene expression but altered the expression of Srif mRNA expression in the periventricular nucleus and Ghrh mRNA expression in the arcuate nucleus consistent with a reduction in GH feedback and concurrent with reduced serum insulin-like growth factor-1. Conversely, GH treatment of SD hamsters increased body mass, which included increased mass of liver and kidneys. Together, these data indicate a role for the GH axis in the determination of seasonal body mass of the Siberian hamster.

  5. Acute downregulation of Type II and Type III iodothyronine deiodinases by photoperiod in peripubertal male and female Siberian hamsters.

    PubMed

    Kampf-Lassin, August; Prendergast, Brian J

    2013-11-01

    Availability of the thyroid hormone triiodothyronine (T3) in the mediobasal hypothalamus plays a central role in seasonal reproductive responses to photoperiod. Across many vertebrates, Type 2 iodothyronine deiodinase (DIO2) is elevated under reproductively stimulatory long days (LD) and synthesizes the conversion of thyroxine to T3; Type 3 iodothyronine deiodinase (DIO3) reduces T3 production and signaling, and is upregulated under reproductively-inhibitory short days (SD). In Siberian hamsters, regulation of hypothalamic T3 is dominated by dio3 expression, whereas dio2 expression is less-consistently affected by photoperiod. In adult hamsters, changes in deiodinase mRNA expression typically require several weeks to manifest, but it is not known whether or how quickly these mechanisms are engaged during the rapid responses to photoperiod observed in young, peri-pubertal hamsters. This experiment tested the hypotheses that (1) deiodinase responses to photoperiod are accelerated in juvenile hamsters and (2) photoperiodic downregulation of deiodinase expression occurs more rapidly than upregulation. Hypothalamic dio2 and dio3 mRNA expression was quantified in male and female Siberian hamsters that were weaned on postnatal day 18 (PND 18) into SD or remained in their natal LD, and on PND 31 were exposed to a single long or short day. In SD males and females, a single long day inhibited dio3 mRNA expression, but did not increase dio2 mRNA. In LD males, a single short day rapidly inhibited dio2 mRNA expression, but did not stimulate expression of dio3 mRNA. Downregulation of dio2 and dio3 mRNAs precedes gonadotrophin responses to day length. Rapid photoperiodic inhibition of deiodinase mRNAs may initiate changes in thyroid hormone signaling in advance of longer-term, melatonin-dependent, responses.

  6. Short-day aggression is independent of changes in cortisol or glucocorticoid receptors in male Siberian hamsters (Phodopus sungorus).

    PubMed

    Scotti, Melissa-Ann L; Rendon, Nikki M; Greives, Timothy J; Romeo, Russell D; Demas, Gregory E

    2015-06-01

    Testosterone mediates aggression in many vertebrates. In some species, aggression remains high during the non-breeding season (e.g., winter), when testosterone levels are low. In Siberian hamsters (Phodopus sungorus), we have demonstrated photoperiodic changes in aggression with hamsters housed in short, "winter-like" days displaying significantly more territorial aggression than long-day animals, despite low levels of testosterone. The mechanisms by which photoperiod regulates aggression, however, remain largely unknown. Adrenocortical hormones (e.g., glucocorticoids) have been implicated in mediating seasonal aggression; circulating concentrations of these hormones have been correlated with aggression in some species. The goal of this study was to examine the role of cortisol and glucocorticoid receptors in mediating photoperiodic changes in aggression in male Siberian hamsters. Males were housed in long or short days and treated with either exogenous cortisol or vehicle. Circulating levels of cortisol, adrenal cortisol content, and aggression were quantified. Lastly, photoperiodic effects on glucocorticoid receptor (GR) protein levels were quantified in limbic brain regions associated with aggression, including medial prefrontal cortex, amygdala, and hippocampus. Short-day hamsters were more aggressive than long-day hamsters, however cortisol treatment did not affect aggression. Photoperiod had no effect on serum or adrenal cortisol or GR levels in the brain regions examined. Taken together, these data suggest that increases in cortisol levels do not cause increases associated with short-day aggression, and further that GR protein levels are not associated with photoperiodic changes in aggression. The results of this study contribute to our understanding of the role of adrenocortical steroids in mediating seasonal aggression. © 2015 Wiley Periodicals, Inc.

  7. Circannual and circadian rhythms of hypothalamic DNA methyltransferase and histone deacetylase expression in male Siberian hamsters (Phodopus sungorus).

    PubMed

    Stevenson, Tyler J

    2017-03-01

    Precise timing of gene transcription is a fundamental component of many biological rhythms. DNA methylation and histone acetylation are two epigenetic modifications that can affect the probability of gene transcription and RNA expression. Enzymes involved in DNA methylation (dnmts) have been shown to exhibit photoperiodic rhythms in expression in the hypothalamus, which coincide with hypothalamic expression of deiodinase type III (dio3), a gene involved in the photoperiodic regulation of reproduction. It is currently unknown whether enzymes involved in histone deacetylation (hdacs) also vary in response to photoperiod, nor have seasonal changes in the circadian waveforms of methylation and/or acetylation enzymes been examined. The present work documents circadian and photoperiodic changes in dnmts and hdacs in whole hypothalamic dissections obtained from male Siberian hamsters (Phodopus sungorus) after 5-6weeks of exposure to SD. The data indicate that short days (SD) markedly inhibit dnmt3a expression, and that SD inhibition of dnmt3a was evident regardless of the alignment of circadian waveforms. Among hdacs, photoperiodic and circadian changes in expression were only observed in hdac4 expression. Recurrent temporal waveforms in epigenetic enzyme expression may provide molecular inputs to the timing systems that reprogram RNA expression to generate daily and annual phenotypic plasticity.

  8. Sleep deprivation attenuates endotoxin-induced cytokine gene expression independent of day length and circulating cortisol in male Siberian hamsters (Phodopus sungorus).

    PubMed

    Ashley, Noah T; Walton, James C; Haim, Achikam; Zhang, Ning; Prince, Laura A; Fruchey, Allison M; Lieberman, Rebecca A; Weil, Zachary M; Magalang, Ulysses J; Nelson, Randy J

    2013-07-15

    Sleep is restorative, whereas reduced sleep leads to negative health outcomes, such as increased susceptibility to disease. Sleep deprivation tends to attenuate inflammatory responses triggered by infection or exposure to endotoxin, such as bacterial lipopolysaccharide (LPS). Previous studies have demonstrated that Siberian hamsters (Phodopus sungorus), photoperiodic rodents, attenuate LPS-induced fever, sickness behavior and upstream pro-inflammatory gene expression when adapted to short day lengths. Here, we tested whether manipulation of photoperiod alters the suppressive effects of sleep deprivation upon cytokine gene expression after LPS challenge. Male Siberian hamsters were adapted to long (16 h:8 h light:dark) or short (8 h:16 h light:dark) photoperiods for >10 weeks, and were deprived of sleep for 24 h using the multiple platform method or remained in their home cage. Hamsters received an intraperitoneal injection of LPS or saline (control) 18 h after starting the protocol, and were killed 6 h later. LPS increased liver and hypothalamic interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF) gene expression compared with vehicle. Among LPS-challenged hamsters, sleep deprivation reduced IL-1 mRNA levels in liver and hypothalamus, but not TNF. IL-1 attenuation was independent of circulating baseline cortisol, which did not increase after sleep deprivation. Conversely, photoperiod altered baseline cortisol, but not pro-inflammatory gene expression in sleep-deprived hamsters. These results suggest that neither photoperiod nor glucocorticoids influence the suppressive effect of sleep deprivation upon LPS-induced inflammation.

  9. Interval timer control of puberty in photoinhibited Siberian hamsters.

    PubMed

    Park, Jin Ho; Kauffman, Alexander S; Paul, Matthew J; Butler, Matthew P; Beery, Annaliese K; Costantini, Ruth M; Zucker, Irving

    2006-10-01

    Puberty, which is markedly delayed in male Siberian hamsters (Phodopus sungorus) born into short day lengths, is controlled by an interval timer regulated by the duration of nocturnal melatonin secretion. Properties of the interval timer were assessed by perturbing normal patterns of melatonin secretion in males gestated and maintained thereafter in 1 of 2 short day lengths, 10 h light/day (10 L) or 12L. Melatonin secretion of short-day hamsters was suppressed by constant light treatment or modified by daily injection of propranolol to mimic nocturnal melatonin durations typical of long-day hamsters. Constant light treatment during weeks 3 to 5 induced early incomplete gonadal growth in 12L but not 10 L hamsters but did not affect late onset of gonadal development indicative of puberty in either photoperiod. Propranolol treatment during postnatal weeks 3 to 5 induced transient growth of the testes and ultimately delayed the timing of puberty by 3 weeks. Similar treatments between weeks 5 and 7 or on alternate weeks for 24 weeks did not affect the interval timer. The first 2 weeks after weaning may constitute a critical period during which the interval timer is highly responsive to photoperiod. Alternatively, the hamsters' photoperiodic history rather than age or developmental stage may be the critical variable. The interpolation of long-day melatonin signals at the time of weaning does not appear to reset the interval timer to its zero position but may reduce timer responsiveness to long-day melatonin signals several weeks later.

  10. Time course and role of the pineal gland in photoperiod control of innate immune cell functions in male Siberian hamsters.

    PubMed

    Yellon, Steven M; Kim, Kiam; Hadley, Allison R; Tran, Long T

    2005-04-01

    The time course of select phagocyte and natural killer activities to short days was determined. In advance of testes regression, circulating granulocyte and monocyte cell numbers in hamsters decreased while lymphocyte numbers increased; phagocytosis and oxidative burst activity also decreased. To determine whether the pineal gland influences these innate immune cell functions, hamsters were exposed to constant light. Photoperiod control of testes weight and basal oxidative burst activity was abolished by treatment with constant light; other phagocyte activities and leukocyte proportions in circulation were not affected. The findings suggest that photoperiod and pineal gland function may regulate certain innate immune activities.

  11. Neonatal monosodium glutamate treatment counteracts circadian arrhythmicity induced by phase shifts of the light-dark cycle in female and male Siberian hamsters.

    PubMed

    Prendergast, Brian J; Onishi, Kenneth G; Zucker, Irving

    2013-07-12

    Studies of rats and voles suggest that distinct pathways emanating from the anterior hypothalamic-retrochiasmatic area and the mediobasal hypothalamic arcuate nucleus independently generate ultradian rhythms (URs) in hormone secretion and behavior. We evaluated the hypothesis that destruction of arcuate nucleus (ARC) neurons, in concert with dampening of suprachiasmatic nucleus (SCN) circadian rhythmicity, would compromize the generation of ultradian rhythms (URs) of locomotor activity. Siberian hamsters retain-->of both sexes treated neonatally with monosodium glutamate (MSG) that destroys ARC neurons were subjected in adulthood to a circadian disrupting phase-shift protocol (DPS) that produces SCN arrhythmia. MSG treatments induced hypogonadism and obesity, retain-->and markedly reduced the size of the optic chiasm and optic nerves. MSG-treated hamsters exhibited normal entrainment to the light-dark cycle, but MSG treatretain-->ment counteracted the circadian arrhythmicity induced by the DPS protocol: only 6% of retain-->MSG-treated hamsters exhibited circadian arrhythmia, whereas 50% of control hamsters were circadian disrupted. In MSG-treated hamsters that retained circadian rhythmicity after DPS treatment, quantitative parameters of URs appeared normal, but in the two MSG-treated hamsters that became circadian arrhythmic after DPS, both dark-phase and light-phase URs were abolished. Although preliminary, these data are consistent with reports in voles suggesting that the combined disruption of SCN and ARC function impairs the expression of behavioral URs. The data also suggest that light thresholds for entrainment of circadian rhythms may be lower than those required to disrupt circadian organization. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Circadian arrhythmia dysregulates emotional behaviors in aged Siberian hamsters

    PubMed Central

    Prendergast, Brian J.; Onishi, Kenneth G.; Patel, Priyesh N.; Stevenson, Tyler J.

    2014-01-01

    Emotional behaviors are influenced by the circadian timing system. Circadian disruptions are associated with depressive-like symptoms in clinical and preclinical populations. Circadian rhythm robustness declines markedly with aging and may contribute to susceptibility to emotional dysregulation in aged individuals. The present experiments used a model of chronic circadian arrhythmia generated noninvasively, via a series of circadian-disruptive light treatments, to investigate interactions between circadian desynchrony and aging on depressive- and anxiety-like behaviors, and on limbic neuroinflammatory gene expression that has been linked with emotionality. We also examined whether a social manipulation (group housing) would attenuate effects of arrhythmia on emotionality. In aged (14-18 months of age) male Siberian hamsters, circadian arrhythmia increased behavioral despair and decreased social motivation, but decreased exploratory anxiety. These effects were not evident in younger (5-9 months of age) hamsters. Social housing (3-5 hamsters/cage) abolished the effects of circadian arrhythmia on emotionality. Circadian arrhythmia alone was without effect on hippocampal or cortical interleukin-1β (IL-1β) and indoleamine 2,3-dioxygenase (Ido) mRNA expression in aged hamsters, but social housing decreased hippocampal IL-1β and Ido mRNAs. The data demonstrate that circadian disruption can negatively impact affective state, and that this effect is pronounced in older individuals. Although clear associations between circadian arrhythmia and constitutive limbic proinflammatory activity were not evident, the present data suggest that social housing markedly inhibits constitutive hippocampal IL-1β and Ido activity, which may contribute to the ameliorating effects of social housing on a number of emotional behaviors. PMID:24333374

  13. Hyperprolactinemia does not promote testicular recrudescence in photoregressed Siberian hamsters.

    PubMed

    Whitten, R D; Youngstrom, T G; Bartness, T J

    1993-07-01

    Serum prolactin (PRL) concentrations, as well as body, epididymal white adipose tissue (EWAT), and testes weights, decrease in Siberian hamsters (Phodopus sungorus sungorus) following short-photoperiod exposure. Previously, we have shown that lesions of the suprachiasmatic nucleus of the hypothalamus (SCNx) block regression of the testes and decreases in body weight and EWAT caused by short day-like, timed daily subcutaneous melatonin infusions in pinealectomized Siberian hamsters and elevate dramatically serum PRL concentrations. We also have shown that SCNx, as well as lesions of the paraventricular nucleus of the hypothalamus (PVNx) and an area immediately ventral to the PVN (subPVN), promote accelerated testicular recrudescence, increases in EWAT and body weights, and increases in serum PRL concentrations, in short-day (SD)-housed, photoregressed Siberian hamsters. The stimulation of the testes seen in these previous studies could have been due to the lesion-induced increases in serum PRL concentrations. Therefore, the purpose of the present experiment was to test whether experimentally induced hyperprolactinemia could stimulate testicular recrudescence. This was accomplished by giving photoregressed, SD-housed Siberian hamsters chronic subcutaneous infusions of ovine PRL (oPRL) to mimic either long-day- or lesion-induced serum concentrations of hamster prolactin (hPRL). No increase in testes, body, or EWAT weights were observed following 5 weeks of oPRL infusions in either group compared with their vehicle-infused counterparts. These data suggest that hyperprolactinemia was not solely responsible for the stimulation of testicular recrudescence in SCNx or PVNx photoregressed, or SCNx pinealectomized hamsters receiving timed melatonin infusions seen previously.

  14. Hematologic, Serologic, and Histologic Profile of Aged Siberian Hamsters (Phodopus sungorus)

    PubMed Central

    McKeon, Gabriel P; Nagamine, Claude M; Ruby, Norman F; Luong, Richard H

    2011-01-01

    Biologic samples from 18 (12 female, 6 male) Siberian hamsters (Phodopus sungorus) representing an aged colony (17 to 27 mo) were examined. Values for CBC and serum biochemical parameters were determined, and macroscopic and microscopic pathologic evaluations were performed. Blood urea nitrogen levels were significantly higher in male (54.2 ± 14 mg/dL) compared with female (35.3 ± 22 mg/dL) hamsters and correlated histologically with a higher incidence of chronic glomerulonephropathy in males (5 of 6 males; 0 of 12 females). All 18 hamsters had histologic evidence of follicular mite infestation. Half (6 of 12) of the female hamsters showed cystic rete ovarii. Other histologic findings included thymic or thyroid branchial cysts (3 of 18), focal enteritis (2 of 18), and single cases of hepatic hemangiosarcoma, renal adenoma, subcutaneous mast cell tumor, cutaneous sebaceous adenoma, cutaneous trichofolliculoma, squamous papilloma of the nonglandular stomach, epididymal cholesteatoma, pyometra, and pituitary craniopharyngeal cyst. This study is the first published report of hematologic and serum chemical values for any population of Siberian hamsters and the first published report showing a potential male predisposition for chronic progressive glomerulonephropathy and a potential female predisposition for cystic rete ovarii. PMID:21640024

  15. Circadian rhythms accelerate wound healing in female Siberian hamsters.

    PubMed

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

    2017-03-15

    Circadian rhythms (CRs) provide temporal regulation and coordination of numerous physiological traits, including immune function. CRs in multiple aspects of immune function are impaired 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 3h after light onset (ZT03) or 2h 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.

  16. 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.

  17. Histaminergic regulation of seasonal metabolic rhythms in Siberian hamsters.

    PubMed

    I'anson, Helen; Jethwa, Preeti H; Warner, Amy; Ebling, Francis J P

    2011-06-01

    We investigated whether histaminergic tone contributes to the seasonal catabolic state in Siberian hamsters by determining the effect of ablation of histaminergic neurons on food intake, metabolic rate and body weight. A ribosomal toxin (saporin) conjugated to orexin-B was infused into the ventral tuberomammillary region of the hypothalamus, since most histaminergic neurons express orexin receptors. This caused not only 75-80% loss of histaminergic neurons in the posterior hypothalamus, but also some loss of other orexin-receptor expressing cells e.g. MCH neurons. In the long-day anabolic state, lesions produced a transient post-surgical decrease in body weight, but the hamsters recovered and maintained constant body weight, whereas weight gradually increased in sham-lesioned hamsters. VO(2) in the dark phase was significantly higher in the lesioned hamsters compared to shams, and locomotor activity also tended to be higher. In a second study in short days, sham-treated hamsters showed the expected seasonal decrease in body weight, but weight remained constant in the lesioned hamsters, as in the long-day study. Lesioned hamsters consumed more during the early dark phase and less during the light phase due to an increase in the frequency of meals during the dark and decreased meal size during the light, and their cumulative food intake in their home cages was greater than in the control hamsters. In summary, ablation of orexin-responsive cells in the posterior hypothalamus blocks the short-day induced decline in body weight by preventing seasonal hypophagia, evidence consistent with the hypothesis that central histaminergic mechanisms contribute to long-term regulation of body weight. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Molecular and immunological characterization of the first allergenic lipocalin in hamster: the major allergen from Siberian hamster (Phodopus sungorus).

    PubMed

    Torres, José Alberto; de Las Heras, Manuel; Maroto, Aroa Sanz; Vivanco, Fernando; Sastre, Joaquín; Pastor-Vargas, Carlos

    2014-08-22

    The most frequent pet allergy is to cat and dog, but in recent years, it has become increasingly popular to have other pets, and the risk of exposure to new allergens is more prevalent. The list of new pets includes hamsters, and one of the most popular hamsters is the Siberian hamster (Phodopus sungorus). The aim of this study was the characterization and cloning of the major allergen from this hamster. The study of its allergenicity and cross-reactivity could improve the specific diagnosis and treatment for hamster-allergic patients. Thirteen Siberian hamster-allergic patients were recruited at the outpatient clinic. Protein extracts were prepared from the hair, urine, and salivary glands of four hamster species (European, golden, Siberian, and Roborovski). IgE-binding proteins were detected by immunoblotting and identified by mass spectrometry. The recombinant protein was produced in Escherichia coli and then purified by metal chelate affinity chromatography. The allergenic properties of the recombinant protein were tested by ELISA and immunoblotting, and biological activity was tested according to capacity for basophil activation. Three IgE-binding proteins were identified in extracts obtained from Siberian hamster hair, urine, and salivary glands. All proteins corresponded to the same protein, which was identified as a lipocalin. This lipocalin had no cross-reactivity with common and golden hamsters. The recombinant allergen was cloned and purified, showing similar IgE reactivity in vitro to Siberian hamster protein extracts. Also, the recombinant allergen was capable of producing biological activation in vivo. The major Siberian hamster allergen was cloned, and allergenic properties were characterized, providing a new tool for specific diagnosis of allergy to Siberian hamster. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. 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.

  20. Melatonin production accompanies arousal from daily torpor in Siberian hamsters.

    PubMed

    Larkin, Jennie E; Yellon, Steven M; Zucker, Irving

    2003-01-01

    Arousal from deep hibernation is accompanied by a transient rise of melatonin (Mel) in circulation; there are no comparable analyses of Mel concentrations in species that undergo much shallower, shorter duration episodes of daily torpor. Serum Mel concentrations were determined during arousal from both natural daily torpor and torpor induced by 2-deoxy-D-glucose (2-DG) treatment (2,500 mg/kg, intraperitoneal [IP]); blood samples were drawn from the retro-orbital sinus of anesthetized Siberian hamsters. For animals kept in darkness during torpor, Mel concentrations were highest during early arousal when thermogenesis is maximal, and they decreased as body temperature increased during arousal and returned to baseline once euthermia was reestablished. In hamsters kept in the light during the torpor bout, Mel concentrations were elevated above basal values during arousal, but the response was significantly blunted in comparison with values recorded in darkness. Increased Mel concentrations were detected in hamsters only during arousal from torpor (either natural or 2-DG induced) and were not simply a result of the drug treatment; hamsters that remained euthermic or manifested mild hypothermia after drug treatment maintained basal Mel concentrations. We propose that increased Mel production may reflect enhanced sympathetic activation associated with intense thermogenesis during arousal from torpor rather than an adjustment of the circadian rhythm of Mel secretion.

  1. Siberian hamster: a new indoor source of allergic sensitization and respiratory disease.

    PubMed

    Bertó, J M; Peláez, A; Fernández, E; Lombardero, M; Ferrer, M

    2002-02-01

    The identification of 'unknown' allergic sensitizations may determine the prognosis and treatment of patients with respiratory airway disease. Currently, the presence in homes of 'exotic' animals as pets is increasing. In this article the Siberian hamster or dwarf hamster (Phodopus sungorus) was identified as a new indoor source of aeroallergens and respiratory disease. The subjects were six outpatients who were treated for asthma and rhinitis. Siberian hamster hair extract was prepared with a standard wt/vol method, and patients were skin-prick tested with the extract. Serum-specific immunoglobulin (Ig)E against the Siberian hamster, common hamster (Cricetus cricetus) and golden hamster (Mesocricetus auratus) was determined. IgE-immunoblotting was also performed for all six sera. Specific bronchial challenge was carried out with the Siberian hamster extract. Skin prick tests (SPT) with the Siberian hamster extract, and specific IgE-antibodies against Siberian hamster, were strongly positive in all six patients. Determinations of specific IgE-antibodies against C. cricetus and M. auratus were negative in all patients. IgE-immunoblotting of the sera revealed two IgE-binding fractions (MW 18 and 32 kDa) in five of the six sera. Specific bronchial provocation tests resulted in early asthmatic responses in the two patients who were challenged. The present study reveals the Siberian hamster to be able to induce both sensitization and disease, and this species of hamster should be taken into consideration as a cause of respiratory disease in exposed subjects. A noteworthy finding was the lack of sensitization in our patients to common hamster allergens (M. auratus and C. cricetus) that are usually tested when hamster allergy is suspected.

  2. Sex differences in photoperiodic and stress-induced enhancement of immune function in Siberian hamsters.

    PubMed

    Bilbo, Staci D; Nelson, Randy J

    2003-12-01

    Siberian hamsters breed during the long days of spring and summer when environmental conditions (e.g., ambient temperatures, food availability) are favorable for reproduction. Environmental conditions may also influence the onset and severity of infection and disease, and photoperiodic alterations in immune function may comprise part of a repertoire of seasonal adaptations to help survive winter. In order to test the hypothesis that animals use day length to anticipate seasonal stressors and adjust immune function, we measured antigen-specific delayed-type-hypersensitivity (DTH) responses in the skin of male and female hamsters during long, "summer-like," or short, "winter-like" days, at baseline and following acute restraint stress. Sex steroid hormones were lower, and cortisol was higher, in males and females during short days. Baseline DTH was enhanced in short- compared to long-day males, and acute stress augmented this effect. In contrast, photoperiod alone did not influence the DTH response in females. As predicted, female hamsters exhibited significantly higher DTH responses than males during long days, but not during short days. However, this enhancement was observed in acutely stressed females only. Cortisol concentrations were significantly higher at baseline in females, and increased more in response to stress, compared to males in both photoperiods. These results suggest that photoperiod provides a useful cue by which stressors in the environment may be anticipated in order to adjust immune function. Furthermore, interactions among reproductive status and stress responses appear to mediate the expression of sex differences in immune responses in hamsters.

  3. Learned magnetic compass orientation by the Siberian hamster, Phodopus sungorus

    SciTech Connect

    Deutschlander, Mark E.; Freake, Michael J.; Borland, Christopher; Phillips, John B.; Madden, R C.; Anderson, Larry E.; Wilson, B W.

    2003-04-01

    Magnetic orientation has been demonstrated in Siberian hamsters, Phodopus sungorus. The behavior, using a nest building assay, shows a directional preference in nest position and appears in this animal to be a learned behavior. Hamsters were housed prior to testing in rectangular cages aligned along perpendicular axes. When subsequently tested in a radially-symmetrical arena, the hamsters positioned their nests in a bimodal distribution that coincided with the magnetic direction of the long-axis of the holding cages. In addition, results are presented that illustrate some of the factors that can influence behavioral responses to the magnetic field. In particular for P. sungorus, holding conditions prior to testing and the presence of non-magnetic cues may influence the strength and expression of magnetic orientation. Failure to consider these and other factors may help to explain why previous attempts to demonstrate magnetic orientation in a number of rodent species have failed or, when positive results have been obtained, have been difficult to replicate in other laboratories.

  4. Artificial light at night alters delayed-type hypersensitivity reaction in response to acute stress in Siberian hamsters.

    PubMed

    Bedrosian, Tracy A; Aubrecht, Taryn G; Kaugars, Katherine E; Weil, Zachary M; Nelson, Randy J

    2013-11-01

    Several physiological and behavioral processes rely on precisely timed light information derived from the natural solar cycle. Using this information, traits have adapted to allow individuals within specific niches to optimize survival and reproduction, but urbanization by humans has significantly altered natural habitats. Nighttime light exposure alters immune function in several species, which could lead to decreased fitness or survival, particularly in the face of an environmental challenge. We exposed male Siberian hamsters (Phodopus sungorus) to five lux of light at night for four weeks, and then administered six hours of acute restraint stress. Delayed-type hypersensitivity (DTH) response was assessed immediately following stress. Acute restraint increased the DTH reaction in dark nights, but exposure to nighttime light prevented this response. Exposure to light at night prolonged the DTH response in non-stressed control hamsters. These results suggest that light pollution may significantly alter physiological responses in Siberian hamsters, particularly in response to a salient environmental challenge such as stress.

  5. Photoperiod Regulates vgf-Derived Peptide Processing in Siberian Hamsters.

    PubMed

    Noli, Barbara; Brancia, Carla; Pilleri, Roberta; D'Amato, Filomena; Messana, Irene; Manconi, Barbara; Ebling, Francis J P; Ferri, Gian-Luca; Cocco, Cristina

    2015-01-01

    VGF mRNA is induced in specific hypothalamic areas of the Siberian hamster upon exposure to short photoperiods, which is associated with a seasonal decrease in appetite and weight loss. Processing of VGF generates multiple bioactive peptides, so the objective of this study was to determine the profile of the VGF-derived peptides in the brain, pituitary and plasma from Siberian hamsters, and to establish whether differential processing might occur in the short day lean state versus long day fat. Antisera against short sequences at the C- or N- termini of proVGF, as well as against NERP-1, TPGH and TLQP peptides, were used for analyses of tissues, and both immunohistochemistry and enzyme linked immunosorbent assay (ELISA) coupled with high-performance liquid (HPLC) or gel chromatography were carried out. VGF peptide immunoreactivity was found within cortex cholinergic perikarya, in multiple hypothalamic nuclei, including those containing vasopressin, and in pituitary gonadotrophs. ELISA revealed that exposure to short day photoperiod led to a down-regulation of VGF immunoreactivity in the cortex, and a less pronounced decrease in the hypothalamus and pituitary, while the plasma VGF levels were not affected by the photoperiod. HPLC and gel chromatography both confirmed the presence of multiple VGF-derived peptides in these tissues, while gel chromatography showed the presence of the VGF precursor in all tissues tested except for the cortex. These observations are consistent with the view that VGF-derived peptides have pleiotropic actions related to changing photoperiod, possibly by regulating cholinergic systems in the cortex, vasopressin hypothalamic pathways, and the reproductive axis.

  6. Photoperiod Regulates vgf-Derived Peptide Processing in Siberian Hamsters

    PubMed Central

    Noli, Barbara; Brancia, Carla; Pilleri, Roberta; D’Amato, Filomena; Messana, Irene; Manconi, Barbara; Ebling, Francis J. P.; Ferri, Gian-Luca; Cocco, Cristina

    2015-01-01

    VGF mRNA is induced in specific hypothalamic areas of the Siberian hamster upon exposure to short photoperiods, which is associated with a seasonal decrease in appetite and weight loss. Processing of VGF generates multiple bioactive peptides, so the objective of this study was to determine the profile of the VGF-derived peptides in the brain, pituitary and plasma from Siberian hamsters, and to establish whether differential processing might occur in the short day lean state versus long day fat. Antisera against short sequences at the C- or N- termini of proVGF, as well as against NERP-1, TPGH and TLQP peptides, were used for analyses of tissues, and both immunohistochemistry and enzyme linked immunosorbent assay (ELISA) coupled with high-performance liquid (HPLC) or gel chromatography were carried out. VGF peptide immunoreactivity was found within cortex cholinergic perikarya, in multiple hypothalamic nuclei, including those containing vasopressin, and in pituitary gonadotrophs. ELISA revealed that exposure to short day photoperiod led to a down-regulation of VGF immunoreactivity in the cortex, and a less pronounced decrease in the hypothalamus and pituitary, while the plasma VGF levels were not affected by the photoperiod. HPLC and gel chromatography both confirmed the presence of multiple VGF-derived peptides in these tissues, while gel chromatography showed the presence of the VGF precursor in all tissues tested except for the cortex. These observations are consistent with the view that VGF-derived peptides have pleiotropic actions related to changing photoperiod, possibly by regulating cholinergic systems in the cortex, vasopressin hypothalamic pathways, and the reproductive axis. PMID:26555143

  7. 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

  8. Effects of sex and scotorefractory state on obesity induced by photostimulation and serum leptin in Siberian hamsters (Phodopus sungorus).

    PubMed

    Cudney, Sarah E; Place, Ned J

    2012-12-01

    The rising prevalence of obesity is associated with an increasing incidence of heart disease, diabetes and other health risks. In addition, severe cases of obesity are associated with an even greater risk of morbidity and mortality. Therefore, animal models of morbid obesity are required to better elucidate the underlying mechanisms. Our investigations in the Siberian hamster (Phodopus sungorus) suggest that pronounced obesity can be reliably induced in this species without relying on genetic manipulation or overly fatty and palatable foods. In a prior study on reproductive aging in female Siberian hamsters, we incidentally observed marked obesity in a group of hamsters that were exposed to a particular photoperiodic regime. In short day (SD) lengths, Siberian hamsters inhibit their reproductive physiology and reduce food intake and body mass. However, hamsters become refractory to SD after 15-20weeks and revert to the long day (LD) phenotype. In the previous study, refractory animals appeared to be particularly sensitive to photostimulation (transfer to LD), in terms of increasing body mass. To test the hypothesis that refractoriness to SD predisposes hamsters to severe obesity, we photostimulated females and males in different states of SD responsiveness (inhibited or refractory). We determined that photostimulation during the SD-refractory state is particularly effective in inducing pronounced obesity and high serum leptin concentration in female hamsters. We propose that this experimental framework is a useful model to investigate the factors and signals that create a predisposition to excessive food intake and body mass, without having to rely on genetic or dietary manipulations. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Low ambient temperature accelerates short-day responses in Siberian hamsters by altering responsiveness to melatonin.

    PubMed

    Larkin, J E; Freeman, D A; Zucker, I

    2001-02-01

    Exposure to low ambient temperatures (Ta) accelerates appearance of the winter phenotype in Siberian hamsters transferred from long to short day lengths. Because melatonin transduces the effects of day length on the neuroendocrine axis, the authors assessed whether low Ta promotes the transition to winterlike traits by accelerating the onset of increased nocturnal melatonin secretion or by enhancing responsiveness to melatonin in short day lengths. Male hamsters were transferred from 16L (16 h light/day) to 8L (8 h light/day) photoperiods and held at 5 degrees C or 22 degrees C. Locomotor activity was recorded continuously, and body mass, testis size, and pelage color were determined biweekly for 8 weeks. The duration of nocturnal locomotion (alpha), a reliable indicator of the duration of nocturnal melatonin secretion, lengthened significantly earlier in hamsters exposed to a Ta of 5 degrees C than 22 degrees C. Cold exposure increased the proportion of hamsters that were photoresponsive: gonadal regression in short days increased from 44% at 22 degrees C to 81% at 5 degrees C (p < 0.05); low Ta did not, however, accelerate testicular regression in animals that were photoresponsive. Nonphotoresponsive animals at 5 degrees C temporarily had longer alphas during the first 4 weeks in short days and significant decreases in body mass and testicular size that were reversed during the ensuing weeks when alpha decreased. In a 2nd experiment, pinealectomized male hamsters infused for 10 h/day with melatonin for 2 weeks had significantly lower body and testes masses when maintained at 5 degrees C but not 22 degrees C. Low-ambient temperature appears to accelerate the appearance of the winter phenotype primarily by increasing target tissue responsiveness to melatonin and to a lesser extent by augmenting the rate at which the duration of nocturnal melatonin secretion increases in short day lengths.

  10. Seasonal pelage changes are synchronized by simulated natural photoperiods in Siberian hamsters (Phodopus sungorus)

    PubMed Central

    Butler, Matthew P.; Zucker, Irving

    2013-01-01

    The extent to which changing day lengths synchronize the seasonal molt was assessed in nine cohorts of male and female Siberian hamsters (Phodopus sungorus) born into a simulated natural photoperiod (SNP) beginning 4 weeks before and ending 12 weeks after the summer solstice. Hamsters in early cohorts displayed rapid somatic and gonadal growth and early puberty, whereas those in later cohorts delayed puberty until the next spring. Despite the varying birth dates and puberty strategies, the seasonal pattern of change in pelage is much better predicted by calendar date than by age in both sexes. Males born over the course of 16 weeks first made the transition to the winter pelage during a 5 week interval beginning on October 25; the autumn molt, however, was not significantly synchronized by either age or calendar date. The autumn molt of females on the other hand began 2 weeks later, and was significantly synchronized to calendar date with no detectable age effects. In both sexes, the autumn molt lagged gonadal and somatic seasonal changes by many weeks. Date of birth did not affect the timing of the spring molt, which was significantly synchronized by calendar date in both sexes. Incrementally changing photoperiods exert a strong organizing effect on the seasonal molt by providing hamsters with timing cues that are absent in laboratory analyses that employ static day lengths and abrupt transitions from summer to winter day lengths, thereby extending and validating conclusions derived from previous analyses. PMID:19425044

  11. Food as a supplementary cue triggers seasonal changes in aggression, but not reproduction, in Siberian hamsters.

    PubMed

    Bailey, Allison M; Rendon, Nikki M; O'Malley, Kyle J; Demas, Gregory E

    2016-12-01

    Animals living in temperate regions prepare for harsh winter conditions by responding to environmental cues that signal resource availability (e.g., food, day length). Siberian hamsters (Phodopus sungorus) breed in long, summer-like days (LD, >14h light), i.e., photoperiods, and undergo robust gonadal regression and become more aggressive when exposed to short, winter-like photoperiods that signal impending limited resources (SD, <10h light). When hamsters are reared within an intermediate photoperiod (ID, 13.5h light), they are reproductively active, but undergo gonadal regression in response to mild food restriction (FR) over 6-12weeks. We hypothesized that short-term (1-2weeks) FR in an ID photoperiod would provide a signal of impending limited resources and initiate the seasonal increase in aggression typical of SD photoperiods, as well as alter reproductive behaviors in advance of gonadal regression. To test this, we housed male and female hamsters in LD or ID photoperiods, with ad libitum (AL) access to food or a 90%-AL ration. We tested aggressive behavior after one week and reproductive behavior after two weeks, and subsequently monitored females for pregnancy and litter production. Both sexes displayed increased aggression in the ID-FR treatment. Untreated male intruders were less likely to ejaculate when paired with ID females during reproductive encounters. ID-FR males were undergoing gonadal regression after two weeks, but were more likely to have ejaculated. Female pregnancy and litter characteristics were unaltered by treatment: females were equally likely to achieve pregnancy and produce comparable litters across treatment groups. Collectively, we demonstrate that a signal of diminishing resources in an ID photoperiod is sufficient to trigger seasonal aggression, but that hamsters are reproductively resilient to inhibitory environmental cues in the short term. Broadly, our findings provide an important context for exploring seasonal changes in

  12. Hypothalamic neuropeptide systems and anticipatory weight change in Siberian hamsters.

    PubMed

    Adam, C L; Mercer, J G

    2001-01-01

    Seasonal animals are able both to programme changes in body weight in response to annual changes in photoperiod (anticipatory regulation) and to correct changes in body weight caused by imposed energetic demand (compensatory regulation). Experimental evidence from the Siberian hamster suggests that seasonally appropriate body weight is continually reset according to photoperiodic history, even when actual body weight is driven away from this target weight by manipulation of energy intake. These characteristics constitute the "sliding set point" of seasonal body weight regulation. To define the mechanisms and molecules underlying anticipatory body weight regulation, we are investigating the involvement of hypothalamic systems with an established role in the compensatory defence of body weight. Weight loss or restricted growth induced by short days (SD) results in low circulating leptin compared with long day (LD) controls. However, this chronic low leptin signal is read differently from acute low leptin resulting from food deprivation; leptin receptor gene expression in the hypothalamic arcuate nucleus (ARC) is lower in SD, whereas food deprivation increases expression levels, suggesting changes in sensitivity to leptin feedback. SD alterations in mRNA levels for a number of hypothalamic neuropeptide and receptor genes appear counter-intuitive for a SD body weight trajectory. However, early increases in ARC cocaine-and amphetamine-regulated transcript (CART) gene expression in SDs could be involved in driving body weight loss or growth restriction. The sites of photoperiod interaction with energy balance neuronal circuitry and the neurochemical encoding of body weight set point require full characterisation. Study of anticipatory regulation in seasonal animals offers new insight into body weight regulation across mammalian species, including man.

  13. 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

  14. Adaptation to short photoperiods augments circadian food anticipatory activity in Siberian hamsters.

    PubMed

    Bradley, Sean P; Prendergast, Brian J

    2014-06-01

    This article is part of a Special Issue "Energy Balance". Both the light-dark cycle and the timing of food intake can entrain circadian rhythms. Entrainment to food is mediated by a food entrainable circadian oscillator (FEO) that is formally and mechanistically separable from the hypothalamic light-entrainable oscillator. This experiment examined whether seasonal changes in day length affect the function of the FEO in male Siberian hamsters (Phodopus sungorus). Hamsters housed in long (LD; 15 h light/day) or short (SD; 9h light/day) photoperiods were subjected to a timed-feeding schedule for 10 days, during which food was available only during a 5h interval of the light phase. Running wheel activity occurring within a 3h window immediately prior to actual or anticipated food delivery was operationally-defined as food anticipatory activity (FAA). After the timed-feeding interval, hamsters were fed ad libitum, and FAA was assessed 2 and 7 days later via probe trials of total food deprivation. During timed-feeding, all hamsters exhibited increases FAA, but FAA emerged more rapidly in SD; in probe trials, FAA was greater in magnitude and persistence in SD. Gonadectomy in LD did not induce the SD-like FAA phenotype, indicating that withdrawal of gonadal hormones is not sufficient to mediate the effects of photoperiod on FAA. Entrainment of the circadian system to light markedly affects the functional output of the FEO via gonadal hormone-independent mechanisms. Rapid emergence and persistent expression of FAA in SD may reflect a seasonal adaptation that directs behavior toward sources of nutrition with high temporal precision at times of year when food is scarce. © 2013.

  15. Adaptation to short photoperiods augments circadian food anticipatory activity in Siberian hamsters

    PubMed Central

    Bradley, Sean P.; Prendergast, Brian J.

    2014-01-01

    Both the light-dark cycle and the timing of food intake can entrain circadian rhythms. Entrainment to food is mediated by a food entrainable circadian oscillator (FEO) that is formally and mechanistically separable from the hypothalamic light-entrainable oscillator. This experiment examined whether seasonal changes in day length affect the function of the FEO in male Siberian hamsters (Phodopus sungorus). Hamsters housed in long (LD; 15 h light/day) or short (SD; 9 h light/day) photoperiods were subjected to a timed-feeding schedule for 10 days, during which food was available only during a 5 h interval of the light phase. Running wheel activity occurring within a 3 h window immediately prior to actual or anticipated food delivery was operationally-defined as food anticipatory activity (FAA). After the timed-feeding interval, hamsters were fed ad libitum, and FAA was assessed 2 and 7 days later via probe trials of total food deprivation. During timed-feeding, all hamsters exhibited increases FAA, but FAA emerged more rapidly in SD; in probe trials, FAA was greater in magnitude and persistence in SD. Gonadectomy in LD did not induce the SD-like FAA phenotype, indicating that withdrawal of gonadal hormones is not sufficient to mediate the effects of photoperiod on FAA. Entrainment of the circadian system to light markedly affects the functional output of the FEO via gonadal hormone-independent mechanisms. Rapid emergence and persistent expression of FAA in SD may reflect a seasonal adaptation that directs behavior toward sources of nutrition with high temporal precision at times of year when food is scarce. PMID:24666779

  16. Melatonin attenuates phenotypic flexibility of energy metabolism in a photoresponsive mammal, the Siberian hamster.

    PubMed

    Boratyński, Jan S; Jefimow, Małgorzata; Wojciechowski, Michał S

    2017-09-01

    The duration of melatonin (MEL) secretion conveys information about day length and initiates a cascade of seasonal phenotypic adjustments in photoresponsive mammals. With shortening days, animals cease reproduction, minimize energy expenditure, enhance thermoregulatory capacity and adjust functioning of the hypothalamic-pituitary-adrenal (HPA) axis to match the winter increase in energy demands. Within each season, stress plays an important role in the flexible adjustments of a phenotype to environmental perturbations. Recent studies have shown that thermal reaction norms of energy metabolism were narrower in winter-acclimated Siberian hamsters, Phodopus sungorus We tested the hypothesis that physiological changes occurring in response to prolonged MEL signals, including changes in the secretion of stress hormones, are responsible for the seasonal decrease in phenotypic flexibility of energy metabolism in photoresponsive mammals. To quantify reaction norms for basal metabolic rate (BMR) and cortisol (CORT) secretion, male Siberian hamsters maintained at a long (16 h:8 h light:dark) photoperiod were acclimated repeatedly for 12 days to 10 and 28°C. As predicted, the phenotypic flexibility of BMR decreased when animals were supplemented with MEL. However, at the same time, mean CORT concentration and the reaction norm for its secretion in response to changes in acclimation temperature increased. These results suggest that decreased sensitivity of HPA axis to CORT signal, rather than changes in CORT level itself, is responsible for the decreased phenotypic flexibility in photoresponsive species. Our results suggest that decreased phenotypic flexibility in winter, together with increased stress hormone secretion, make photosensitive species more vulnerable to climate change. © 2017. Published by The Company of Biologists Ltd.

  17. Hypothalamic over-expression of VGF in the Siberian hamster increases energy expenditure and reduces body weight gain

    PubMed Central

    Brameld, John M.; Hill, Phil; Cocco, Cristina; Noli, Barbara; Ferri, Gian-Luca; Barrett, Perry; Ebling, Francis J. P.; Jethwa, Preeti H.

    2017-01-01

    VGF (non-acronymic) was first highlighted to have a role in energy homeostasis through experiments involving dietary manipulation in mice. Fasting increased VGF mRNA in the Arc and levels were subsequently reduced upon refeeding. This anabolic role for VGF was supported by observations in a VGF null (VGF-/-) mouse and in the diet-induced and gold-thioglucose obese mice. However, this anabolic role for VGF has not been supported by a number of subsequent studies investigating the physiological effects of VGF-derived peptides. Intracerebroventricular (ICV) infusion of TLQP-21 increased resting energy expenditure and rectal temperature in mice and protected against diet-induced obesity. Similarly, ICV infusion of TLQP-21 into Siberian hamsters significantly reduced body weight, but this was due to a decrease in food intake, with no effect on energy expenditure. Subsequently NERP-2 was shown to increase food intake in rats via the orexin system, suggesting opposing roles for these VGF-derived peptides. Thus to further elucidate the role of hypothalamic VGF in the regulation of energy homeostasis we utilised a recombinant adeno-associated viral vector to over-express VGF in adult male Siberian hamsters, thus avoiding any developmental effects or associated functional compensation. Initially, hypothalamic over-expression of VGF in adult Siberian hamsters produced no effect on metabolic parameters, but by 12 weeks post-infusion hamsters had increased oxygen consumption and a tendency to increased carbon dioxide production; this attenuated body weight gain, reduced interscapular white adipose tissue and resulted in a compensatory increase in food intake. These observed changes in energy expenditure and food intake were associated with an increase in the hypothalamic contents of the VGF-derived peptides AQEE, TLQP and NERP-2. The complex phenotype of the VGF-/- mice is a likely consequence of global ablation of the gene and its derived peptides during development, as well

  18. Hypothalamic over-expression of VGF in the Siberian hamster increases energy expenditure and reduces body weight gain.

    PubMed

    Lewis, Jo E; Brameld, John M; Hill, Phil; Cocco, Cristina; Noli, Barbara; Ferri, Gian-Luca; Barrett, Perry; Ebling, Francis J P; Jethwa, Preeti H

    2017-01-01

    VGF (non-acronymic) was first highlighted to have a role in energy homeostasis through experiments involving dietary manipulation in mice. Fasting increased VGF mRNA in the Arc and levels were subsequently reduced upon refeeding. This anabolic role for VGF was supported by observations in a VGF null (VGF-/-) mouse and in the diet-induced and gold-thioglucose obese mice. However, this anabolic role for VGF has not been supported by a number of subsequent studies investigating the physiological effects of VGF-derived peptides. Intracerebroventricular (ICV) infusion of TLQP-21 increased resting energy expenditure and rectal temperature in mice and protected against diet-induced obesity. Similarly, ICV infusion of TLQP-21 into Siberian hamsters significantly reduced body weight, but this was due to a decrease in food intake, with no effect on energy expenditure. Subsequently NERP-2 was shown to increase food intake in rats via the orexin system, suggesting opposing roles for these VGF-derived peptides. Thus to further elucidate the role of hypothalamic VGF in the regulation of energy homeostasis we utilised a recombinant adeno-associated viral vector to over-express VGF in adult male Siberian hamsters, thus avoiding any developmental effects or associated functional compensation. Initially, hypothalamic over-expression of VGF in adult Siberian hamsters produced no effect on metabolic parameters, but by 12 weeks post-infusion hamsters had increased oxygen consumption and a tendency to increased carbon dioxide production; this attenuated body weight gain, reduced interscapular white adipose tissue and resulted in a compensatory increase in food intake. These observed changes in energy expenditure and food intake were associated with an increase in the hypothalamic contents of the VGF-derived peptides AQEE, TLQP and NERP-2. The complex phenotype of the VGF-/- mice is a likely consequence of global ablation of the gene and its derived peptides during development, as well

  19. Cholecystokinin-33 acutely attenuates food foraging, hoarding and intake in Siberian hamsters

    PubMed Central

    Teubner, Brett J.W.; Bartness, Timothy J.

    2009-01-01

    Neurochemicals that stimulate food foraging and hoarding in Siberian hamsters are becoming more apparent, but we do not know if cessation of these behaviors is due to waning of excitatory stimuli and/or the advent of inhibitory factors. Cholecystokinin (CCK) may be such an inhibitory factor as it is the prototypic gastrointestinal satiety peptide and is physiologically important in decreasing food intake in several species including Siberian hamsters. Systemic injection of CCK-33 in laboratory rats decreases food intake, doing so to a greater extent than CCK-8. We found minimal effects of CCK-8 on food foraging and hoarding previously in Siberian hamsters, but have not tested CCK-33. Therefore, we asked: Does CCK-33 decrease normal levels or food deprivation-induced increases in food foraging, hoarding and intake? Hamsters were housed in a wheel running-based foraging system with simulated burrows to test the effects of peripheral injections of CCK-33 (13.2, 26.4, or 52.8 μg/kg body mass), with or without a preceding 56 h food deprivation. The highest dose of CCK-33 caused large baseline reductions in all three behaviors for the 1st h post injection compared with saline; in addition, the intermediate CCK-33 dose was sufficient to curtail food intake and foraging during the 1st h. In food deprived hamsters, we used a 52.8 μg/kg body mass dose of CCK-33 which decreased food intake, hoarding, and foraging almost completely compared with saline controls for 1 h. Therefore, CCK-33 appears to be a potent inhibitor of food intake, hoarding, and foraging in Siberian hamsters. PMID:20025915

  20. Co-infection of the Siberian hamster (Phodopus sungorus) with a novel Helicobacter sp. and Campylobacter sp.

    PubMed

    Nagamine, Claude M; Shen, Zeli; Luong, Richard H; McKeon, Gabriel P; Ruby, Norman F; Fox, James G

    2015-05-01

    We report the isolation of a novel helicobacter isolated from the caecum of the Siberian hamster (Phodopus sungorus). Sequence analysis showed 97% sequence similarity to Helicobacter ganmani. In addition, we report the co-infection of these Siberian hamsters with a Campylobacter sp. and a second Helicobacter sp. with 99% sequence similarity to Helicobacter sp. flexispira taxon 8 (Helicobacter bilis), a species isolated previously from patients with bacteraemia. Gross necropsy and histopathology did not reveal any overt pathological lesions of the liver and gastrointestinal tract that could be attributed to the Helicobacter or Campylobacter spp. infections. This is the first helicobacter to be identified in the Siberian hamster and the first report of co-infection of Helicobacter spp. and Campylobacter sp. in asymptomatic Siberian hamsters.

  1. Co-infection of the Siberian hamster (Phodopus sungorus) with a novel Helicobacter sp. and Campylobacter sp.

    PubMed Central

    Shen, Zeli; Luong, Richard H.; McKeon, Gabriel P.; Ruby, Norman F.; Fox, James G.

    2015-01-01

    We report the isolation of a novel helicobacter isolated from the caecum of the Siberian hamster (Phodopus sungorus). Sequence analysis showed 97 % sequence similarity to Helicobacter ganmani. In addition, we report the co-infection of these Siberian hamsters with a Campylobacter sp. and a second Helicobacter sp. with 99 % sequence similarity to Helicobacter sp. flexispira taxon 8 (Helicobacter bilis), a species isolated previously from patients with bacteraemia. Gross necropsy and histopathology did not reveal any overt pathological lesions of the liver and gastrointestinal tract that could be attributed to the Helicobacter or Campylobacter spp. infections. This is the first helicobacter to be identified in the Siberian hamster and the first report of co-infection of Helicobacter spp. and Campylobacter sp. in asymptomatic Siberian hamsters. PMID:25752854

  2. Diet affects resting, but not basal metabolic rate of normothermic Siberian hamsters acclimated to winter.

    PubMed

    Gutowski, Jakub P; Wojciechowski, Michał S; Jefimow, Małgorzata

    2011-12-01

    We examined the effect of different dietary supplements on seasonal changes in body mass (m(b)), metabolic rate (MR) and nonshivering thermogenesis (NST) capacity in normothermic Siberian hamsters housed under semi-natural conditions. Once a week standard hamster food was supplemented with either sunflower and flax seeds, rich in polyunsaturated fatty acids (FA), or mealworms, rich in saturated and monounsaturated FA. We found that neither of these dietary supplements affected the hamsters' normal winter decrease in m(b) and fat content nor their basal MR or NST capacity. NST capacity of summer-acclimated hamsters was lower than that of winter-acclimated ones. The composition of total body fat reflected the fat composition of the dietary supplements. Resting MR below the lower critical temperature of the hamsters, and their total serum cholesterol concentration were lower in hamsters fed a diet supplemented with mealworms than in hamsters fed a diet supplemented with seeds. These results indicate that in mealworm-fed hamsters energy expenditure in the cold is lower than in animals eating a seed-supplemented diet, and that the degree of FA unsaturation of diet affects energetics of heterotherms, not only during torpor, but also during normothermy. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Sex-specific modulation of the gut microbiome and behavior in Siberian hamsters.

    PubMed

    Sylvia, Kristyn E; Jewell, Cathleen P; Rendon, Nikki M; St John, Emma A; Demas, Gregory E

    2017-02-01

    The gut microbiome is a diverse, host-specific, and symbiotic bacterial environment that is critical for mammalian survival and exerts a surprising yet powerful influence on brain and behavior. Gut dysbiosis has been linked to a wide range of physical and psychological disorders, including autism spectrum disorders and anxiety, as well as autoimmune and inflammatory disorders. A wealth of information on the effects of dysbiosis on anxiety and depression has been reported in laboratory model systems (e.g., germ-free mice); however, the effects of microbiome disruption on social behaviors (e.g., aggression) of non-model species that may be particularly important in understanding many aspects of physiology and behavior have yet to be fully explored. Here we assessed the sex-specific effects of a broad-spectrum antibiotic on the gut microbiome and its effects on social behaviors in male and female Siberian hamsters (Phodopus sungorus). In Experiment 1, we administered a broad-spectrum antibiotic on a short-term basis and found that antibiotic treatment altered the microbial communities in the gut in male and female hamsters. In Experiment 2, we tested the effects of single versus repeated antibiotic treatment (including a recovery phase) on behavior, and found that two, but not one, treatments caused marked decreases in aggressive behavior, but not other social behaviors, in males; aggression returned to normal levels following recovery. Antibiotic-treated females, in contrast, showed decreased aggression after a single treatment, with all other social behaviors unaffected. Unlike males, female aggression did not return to normal during either recovery period. The present findings demonstrate that modest antibiotic treatment results in marked disruption of the gut microbiome in hamsters, akin to research done in other rodent species and humans. Further, we show that treatment with a broad-spectrum antibiotic, which has dysbiotic effects, also has robust, sex

  4. 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

  5. Leptin mediates seasonal variation in some but not all symptoms of sickness in Siberian hamsters.

    PubMed

    Carlton, Elizabeth D; Demas, Gregory E

    2014-11-01

    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. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Dim light at night disrupts the short-day response in Siberian hamsters.

    PubMed

    Ikeno, Tomoko; Weil, Zachary M; Nelson, Randy J

    2014-02-01

    Photoperiodic regulation of physiology, morphology, and behavior is crucial for many animals to survive seasonally variable conditions unfavorable for reproduction and survival. The photoperiodic response in mammals is mediated by nocturnal secretion of melatonin under the control of a circadian clock. However, artificial light at night caused by recent urbanization may disrupt the circadian clock, as well as the photoperiodic response by blunting melatonin secretion. Here we examined the effect of dim light at night (dLAN) (5lux of light during the dark phase) on locomotor activity rhythms and short-day regulation of reproduction, body mass, pelage properties, and immune responses of male Siberian hamsters. Short-day animals reduced gonadal and body mass, decreased spermatid nuclei and sperm numbers, molted to a whiter pelage, and increased pelage density compared to long-day animals. However, animals that experienced short days with dLAN did not show these short-day responses. Moreover, short-day specific immune responses were altered in dLAN conditions. The nocturnal activity pattern was blunted in dLAN hamsters, consistent with the observation that dLAN changed expression of the circadian clock gene, Period1. In addition, we demonstrated that expression levels of genes implicated in the photoperiodic response, Mel-1a melatonin receptor, Eyes absent 3, thyroid stimulating hormone receptor, gonadotropin-releasing hormone, and gonadotropin-inhibitory hormone, were higher in dLAN animals than those in short-day animals. These results suggest that dLAN disturbs the circadian clock function and affects the molecular mechanisms of the photoperiodic response.

  7. 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.

  8. Acute melatonin treatment alters dendritic morphology and circadian clock gene expression in the hippocampus of Siberian hamsters.

    PubMed

    Ikeno, Tomoko; Nelson, Randy J

    2015-02-01

    In the hippocampus of Siberian hamsters, dendritic length and dendritic complexity increase in the CA1 region whereas dendritic spine density decreases in the dentate gyrus region at night. However, the underlying mechanism of the diurnal rhythmicity in hippocampal neuronal remodeling is unknown. In mammals, most daily rhythms in physiology and behaviors are regulated by a network of circadian clocks. The central clock, located in the hypothalamus, controls melatonin secretion at night and melatonin modifies peripheral clocks by altering expression of circadian clock genes. In this study, we examined the effects of acute melatonin treatment on the circadian clock system as well as on morphological changes of hippocampal neurons. Male Siberian hamsters were injected with melatonin in the afternoon; 4 h later, mRNA levels of hypothalamic and hippocampal circadian clock genes and hippocampal neuron dendritic morphology were assessed. In the hypothalamus, melatonin treatment did not alter Period1 and Bmal1 expression. However, melatonin treatment increased both Period1 and Bmal1 expression in the hippocampus, suggesting that melatonin affected molecular oscillations in the hippocampus. Melatonin treatment also induced rapid remodeling of hippocampal neurons; melatonin increased apical dendritic length and dendritic complexity in the CA1 region and reduced the dendritic spine density in the dentate gyrus region. These data suggest that structural changes in hippocampal neurons are regulated by a circadian clock and that melatonin functions as a nighttime signal to coordinate the diurnal rhythm in neuronal remodeling. © 2014 Wiley Periodicals, Inc.

  9. Orchestration of gene expression across the seasons: Hypothalamic gene expression in natural photoperiod throughout the year in the Siberian hamster

    PubMed Central

    Petri, Ines; Diedrich, Victoria; Wilson, Dana; Fernández-Calleja, José; Herwig, Annika; Steinlechner, Stephan; Barrett, Perry

    2016-01-01

    In nature Siberian hamsters utilize the decrement in day length following the summer solstice to implement physiological adaptations in anticipation of the forthcoming winter, but also exploit an intrinsic interval timer to initiate physiological recrudescence following the winter solstice. However, information is lacking on the temporal dynamics in natural photoperiod of photoperiodically regulated genes and their relationship to physiological adaptations. To address this, male Siberian hamsters born and maintained outdoors were sampled every month over the course of one year. As key elements of the response to photoperiod, thyroid hormone signalling components were assessed in the hypothalamus. From maximum around the summer solstice (late-June), Dio2 expression rapidly declined in advance of physiological adaptations. This was followed by a rapid increase in Mct8 expression (T3/T4 transport), peaking early-September before gradually declining to minimum expression by the following June. Dio3 showed a transient peak of expression beginning late-August. A recrudescence of testes and body mass occurred from mid-February, but Dio2 expression remained low until late-April of the following year, converging with the time of year when responsiveness to short-day length is re-established. Other photoperiodically regulated genes show temporal regulation, but of note is a transient peak in Gpr50 around late-July. PMID:27406810

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

    PubMed

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

    2012-10-01

    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 whether disparate coupling assays index a common mechanism, we examined whether there is covariation 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 nonresponders (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 were 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 3 distinct lighting conditions, suggesting a common mechanism wherein individual differences reflect variation in circadian coupling.

  11. Photoperiod alters duration and intensity of non-rapid eye movement sleep following immune challenge in Siberian hamsters (Phodopus sungorus).

    PubMed

    Ashley, Noah T; Zhang, Ning; Weil, Zachary M; Magalang, Ulysses J; Nelson, Randy J

    2012-07-01

    Sleep is regulated by circadian and homeostatic processes, but can be altered by infectious disease. During infection or exposure to inflammatory stimuli, such as bacterial lipopolysaccharide (LPS), the duration and intensity of non-rapid eye movement sleep (NREMS), as measured by electoencephalogram (EEG) delta waves (.5-4 Hz), increase. These sleep alterations are hypothesized to conserve or redirect energy for immune system activation. Many vertebrates exhibit seasonal changes in immune function and sleep-wake cycle, and photoperiod (day length) serves as a reliable environmental cue. For example, winter is energetically demanding for most animals, and Siberian hamsters (Phodopus sungorus) adapted to short winter day lengths display reduced fever after LPS administration to presumably conserve energy. We hypothesized that short days increase the duration and intensity of NREMS after LPS challenge to create additional energy savings, despite evidence to the contrary that high fever is associated with increased NREMS. Male hamsters were housed under long (16 h light (L):8 h dark (D)) or short (8L:16D) day lengths, and chronically implanted with transmitters that recorded EEG and electromyogram (EMG) biopotentials simultaneously or core body temperature. After >10 wks in photoperiod conditions, hamsters received an i.p. injection of LPS or saline (control), and vigilance states (duration and distribution of NREMS, rapid eye movement sleep (REMS), and wakefulness) and EEG delta power spectra (NREMS intensity) were assessed. As expected, LPS treatment increased the duration and intensity of NREMS compared to controls. Hamsters adapted to short photoperiods exhibited cumulatively larger increases in NREMS duration and EEG delta wave amplitude 0-8 h after LPS injection compared to long-day LPS-treated hamsters despite short-day attenuation of fever. These results suggest a seasonal decoupling of LPS-induced fever with sleep to promote energy conservation during

  12. Asymmetric learning to avoid heterospecific males in Mesocricetus hamsters.

    PubMed

    delBarco-Trillo, Javier; Johnston, Robert E

    2012-08-01

    If a female mates with a male of a closely related species, her fitness is likely to decline. Consequently, females may develop behavioral mechanisms to avoid mating with heterospecific males. In some species, one such mechanism is for adult females to learn to discriminate against heterospecific males after exposure to such males. We have previously shown that adult, female Syrian hamsters (Mesocricetus auratus) learn to discriminate against male Turkish hamsters (Mesocricetus brandti) after exposure to a single heterospecific male during 8 days across a wire-mesh barrier. Here we repeated that experiment but this time we exposed female Turkish hamsters to a male Syrian hamster for 8 days and then measured sexual and aggressive behaviors towards that heterospecific male and towards a conspecific male. In contrast to female Syrian hamsters, female Turkish hamsters did not differ in their latency to go into lordosis or in any measure of aggression towards either type of male. Female Turkish hamsters spent less time in lordosis with the heterospecific male, but the percentage of trials in which females copulated with conspecific and heterospecific males did not differ. When comparing females from both species that had been exposed to a heterospecific male for 8days, female Syrian hamsters copulated less and were more aggressive towards the heterospecific male compared to the behavior of female Turkish hamsters. We discuss how this asymmetric response between females of the two species may be due to the much larger geographical range of Turkish hamsters compared to Syrian hamsters.

  13. An Intact Dorsomedial Posterior Arcuate Nucleus is Not Necessary for Photoperiodic Responses in Siberian Hamsters1

    PubMed Central

    Teubner, Brett J.W.; Leitner, Claudia; Thomas, Michael A.; Ryu, Vitaly; Bartness, Timothy J.

    2015-01-01

    Seasonal responses of many animal species are triggered by changes in daylength and its transduction into a neuroendocrine signal by the pineal gland through the nocturnal duration of melatonin (MEL) release. The precise central sites necessary to receive, transduce, and relay the short day (SD) fall-winter MEL signals into seasonal responses and changes in physiology and behavior are unclear. In Siberian hamsters, SDs trigger decreases in body and lipid mass, testicular regression and pelage color changes. Several candidate genes and their central sites of expression have been proposed as components of the MEL transduction system with considerable recent focus on the arcuate nucleus (ARC) and its component, the dorsomedial posterior arcuate nucleus (dmpARC). This site has been postulated as a critical relay of SD information through the modulation of a variety of neurochemicals/receptors important for the control of energy balance. Here the necessity of an intact dmpARC for SD responses was tested by making electrolytic lesions of the Siberian hamster dmpARC and then exposing them to either long days (LD) or SDs for 12 weeks. The SD typical decreases in body and fat mass, food intake, testicular volume, serum testosterone concentrations, pelage color change and increased UCP-1 protein expression (a proxy for brown adipose tissue thermogenesis) all occurred despite the lack of an intact dmpARC. Although the Siberian hamster dmpARC contains photoperiod-modulated constituents, these data demonstrate that an intact dmpARC is not necessary for SD responses and not integral to the seasonal energy- and reproductive-related responses measured here. PMID:25647158

  14. Peripheral ghrelin injections stimulate food intake, foraging, and food hoarding in Siberian hamsters.

    PubMed

    Keen-Rhinehart, Erin; Bartness, Timothy J

    2005-03-01

    Fasting triggers many effects, including increases in circulating concentrations of ghrelin, a primarily stomach-derived orexigenic hormone. Exogenous ghrelin treatment stimulates food intake, implicating it in fasting-induced increases in feeding, a consummatory ingestive behavior. In Siberian hamsters, fasting also stimulates appetitive ingestive behaviors such as foraging and food hoarding. Therefore, we tested whether systemic ghrelin injections (3, 30, and 200 mg/kg) would stimulate these appetitive behaviors using a running wheel-based food delivery system coupled with simulated burrow housing. We also measured active ghrelin plasma concentrations after exogenous ghrelin treatment and compared them to those associated with fasting. Hamsters had the following: 1) no running wheel access, free food; 2) running wheel access, free food; or 3) foraging requirement (10 revolutions/pellet), no free food. Ghrelin stimulated foraging at 0-1, 2-4, and 4-24 h postinjection but failed to affect wheel running activity not coupled to food. Ghrelin stimulated food intake initially (200-350%, first 4 h) across all groups; however, in hamsters with a foraging requirement, ghrelin also stimulated food intake 4-24 h postinjection (200-250%). Ghrelin stimulated food hoarding 2-72 h postinjection (100-300%), most markedly 2-4 h postinjection in animals lacking a foraging requirement (635%). Fasting increased plasma active ghrelin concentrations in a time-dependent fashion, with the 3- and 30-mg/kg dose creating concentrations of the peptide comparable to those induced by 24-48 h of fasting. Collectively, these data suggest that exogenous ghrelin, similar to fasting, increases appetitive behaviors (foraging, hoarding) by Siberian hamsters, but dissimilar to fasting in this species, stimulates food intake.

  15. 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.

  16. 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.

  17. Matrix metalloproteinase inhibition influences aspects of photoperiod stimulated ovarian recrudescence in Siberian hamsters.

    PubMed

    Shahed, Asha; Simmons, Jamie J; Featherstone, Sydney L; Young, Kelly A

    2015-05-15

    Blocking matrix metalloproteinase (MMP) activity in vivo with inhibitor GM6001 impedes photostimulated ovarian recrudescence in photoregressed Siberian hamsters. Since direct and indirect effects of MMPs influence a myriad of ovarian functions, we investigated the effect of in vivo MMP inhibition during recrudescence on ovarian mRNA expression of steroidogenic acute regulatory protein (StAR), 3β-hydroxysteroid dehydrogenase (3β-HSD), Cyp19a1 aromatase, epidermal growth factor receptor (EGFR), amphiregulin (Areg), estrogen receptors (Esr1 and Esr2), tissue inhibitors of MMPs (TIMP-1,-2,-3), proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor A (VEGFA), its receptor VEGFR-2, and angiopoietin-2 (Ang-2). Female Siberian hamsters were randomly assigned to one of four photoperiod groups: stimulatory long (LD) or inhibitory short (SD) photoperiods, or transferred from SD to LD for 2 weeks (post-transfer, PT). Half of the PT hamsters were injected (ip) daily with GM6001 (PTG). SD exposure reduced ovarian StAR, 3β-HSD, Cyp19a1, Esr1, Esr2, TIMPs 2-3, PCNA, VEGFR-2 and Ang-2 mRNA expression (p<0.05), and 2 weeks of photostimulation restored mRNA expression of 3β-HSD and PCNA and increased Areg and VEGFA mRNA expression in the PT group. GM6001 treatment during photostimulation (PTG) increased TIMP-1, -2 and -3 and PCNA mRNA, but inhibited Areg mRNA expression compared to PT. Neither photoperiod nor GM6001 altered EGFR expression. Results of this study suggest that in vivo inhibition of MMP activity by GM6001 may impede ovarian recrudescence, particularly follicular growth, in two ways: (1) directly by partially inhibiting the release of EGFR ligands like Areg, thereby potentially affecting EGFR activation and its downstream pathway, and (2) indirectly by its effect on TIMPs which themselves can affect proliferation, angiogenesis and follicular growth.

  18. Effects of exogenous leptin on seasonal reproductive responses to interacting environmental cues in female Siberian hamsters.

    PubMed

    Bailey, Allison M; Legan, Sandra J; Meretsky, Vicky J; Demas, Gregory E

    2017-09-01

    Animals living in temperate climates respond to environmental cues that signal current and future resource availability to ensure that energy resources are available to support reproduction. Siberian hamsters (Phodopus sungorus) undergo robust gonadal regression in short, winter-like photoperiods as well as in response to mild food restriction in intermediate photoperiods. The goal of the present study was to investigate whether leptin is a relevant metabolic signal in regulating gonadal regression in response to diminishing food availability. Adult female hamsters housed in short-day (winter-like) or intermediate (fall-like) photoperiods received either ad libitum access to food or mild food restriction (90% of ad libitum intake) and were treated with either leptin or a vehicle for five weeks in order to determine the ability of leptin to inhibit gonadal regression. At the end of five weeks, vehicle-treated hamsters showed physiological signs associated with ongoing gonadal regression, such as decreases in body mass and food intake, cessation of estrous cycling, and small decreases in reproductive tissue mass. Leptin did not modify changes in body mass, food intake, hormone concentration, or tissue mass, but showed a tendency to support estrous cycling, particularly in response to food restriction in the intermediate photoperiod treatment. Overall, leptin appears to play a minor role in coordinating reproductive responses to multiple environmental cues, at least in the early stages of gonadal regression. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Role of NPY and its receptor subtypes in foraging, food hoarding, and food intake by Siberian hamsters.

    PubMed

    Day, Diane E; Keen-Rhinehart, Erin; Bartness, Timothy J

    2005-07-01

    Fasting has widespread physiological and behavioral effects such as increases in arcuate nucleus neuropeptide Y (NPY) gene expression in rodents, including Siberian hamsters. Fasting also stimulates foraging and food hoarding (appetitive ingestive behaviors) by Siberian hamsters but does relatively little to change food intake (consummatory ingestive behavior). Therefore, we tested the effects of third ventricular NPY Y1 ([Pro(34)]NPY) or Y5 ([D-Trp(34)]NPY) receptor agonists on these ingestive behaviors using a wheel running-based food delivery system coupled with simulated burrow housing. Siberian hamsters had 1) no running wheel access and free food, 2) running wheel access and free food, or 3) foraging requirements (10 or 50 revolutions/pellet). NPY (1.76 nmol) stimulated food intake only during the first 4 h postinjection ( approximately 200-1,000%) and mostly in hamsters with a foraging requirement. The Y1 receptor agonist markedly increased food hoarding (250-1,000%), increased foraging as well as wheel running per se, and had relatively little effect on food intake (<250%). Unlike NPY, the Y5 agonist significantly increased food intake, especially in foraging animals ( approximately 225-800%), marginally increased food hoarding (250-500%), and stimulated foraging and wheel running 4-24 h postinjection, with the distribution of earned pellets favoring eating versus hoarding across time. Across treatments, food hoarding predominated early postinjection, whereas food intake tended to do so later. Collectively, NPY stimulated both appetitive and consummatory ingestive behaviors in Siberian hamsters involving Y1/Y5 receptors, with food hoarding and foraging/wheel running (appetitive) more involved with Y1 receptors and food intake (consummatory) with Y5 receptors.

  20. Short-day-like body weight changes do not prevent fat pad compensation after lipectomy in Siberian hamsters.

    PubMed

    Mauer, M M; Bartness, T J

    1997-01-01

    Long-day (LD)-housed Siberian hamsters show compensatory increases in white adipose tissue (WAT) weight after lipectomy, whereas hamsters exposed to short days (SDs) for a long duration (22 wk) do not. We tested whether SD-induced body weight changes prevent fat pad compensation after lipectomy. In experiment 1, hamsters with lesions of the paraventricular nucleus of the hypothalamus (PVNx) rapidly increased body weight similarly to 22-wk SD-exposed hamsters. In experiment 2, LD-housed hamsters were food restricted for 22 wk and then pair fed with SD-housed hamsters for 12 wk to produce body weight changes mimicking those of ad libitum-fed SD-exposed animals. Epididymal WAT (EWAT) lipectomy (EWATx) of PVNx or food-restricted hamsters elicited compensatory increases in retroperitoneal and inguinal WAT (RWAT and IWAT) weights. Unlike other fat pads, EWAT was less affected by food restriction or PVNx than by SD exposure. In general, food restriction decreased adipocyte number, whereas SD exposure decreased adipocyte size. PVNx increased RWAT adipocyte size and IWAT adipocyte number. These results suggest that the lack of body fat compensation by EWATx hamsters exposed to SDs for a long duration is due to SD-associated responses other than body weight changes per se.

  1. Rapid Induction of Hypothalamic Iodothyronine Deiodinase Expression by Photoperiod and Melatonin in Juvenile Siberian Hamsters (Phodopus sungorus)

    PubMed Central

    Prendergast, Brian J.; Pyter, Leah M.; Kampf-Lassin, August; Patel, Priyesh N.

    2013-01-01

    Production of T3 in the mediobasal hypothalamus is critical for regulation of seasonal reproductive physiology. Type 2 iodothyronine deiodinase (DIO2) and DIO3 enzymes catalyze the prohormone T4 into biologically-active T3 and biologically-inactive rT3, respectively. In several seasonally-breeding vertebrates, DIO2 and DIO3 expression is implicated in photoperiod signal transduction in adulthood. These experiments tested the hypothesis that juvenile Siberian hamsters, which are highly responsive to photoperiod at weaning (postnatal day [PND]18), exhibit rapid and sustained changes in hypothalamic dio3 mRNA expression during photoperiod-induced and photoperiod-inhibited puberty. Hypothalamic dio2 and dio3 expression was measured via quantitative PCR in hamsters born and reared in a long-day photoperiod (15L:9D) and weaned on PND18 into short-day photoperiods (9L:15D). In SD males, hypothalamic dio3 mRNA was elevated 2.5-fold within 3 days (PND21) and continued to increase (>20-fold) through PND32; changes in dio3 mRNA preceded inhibition of gonadotropin (FSH) secretion and gonadal regression in SD. Females exhibited comparable dio3 responses to SD. In LD males, dio3 remained low and invariant from PND18–PND32. In contrast, dio2 mRNA rose conspicuously on PND21, independent of photoperiod, returning to basal levels thereafter. In LD, a single afternoon melatonin (MEL) injection on PND18 or PND20 was sufficient to increase hypothalamic dio3 mRNA, and dio3 increased in proportion to the number of successive days of MEL treatment. SD photoperiods and MEL exert rapid, sustained, and additive effects on hypothalamic dio3 mRNA, which may play a central role in inhibiting maturation of the peripubertal hypothalamo-pituitary-gonadal axis. PMID:23295738

  2. Rapid induction of hypothalamic iodothyronine deiodinase expression by photoperiod and melatonin in juvenile Siberian hamsters (Phodopus sungorus).

    PubMed

    Prendergast, Brian J; Pyter, Leah M; Kampf-Lassin, August; Patel, Priyesh N; Stevenson, Tyler J

    2013-02-01

    Production of T(3) in the mediobasal hypothalamus is critical for regulation of seasonal reproductive physiology. Type 2 iodothyronine deiodinase (DIO2) and DIO3 enzymes catalyze the prohormone T(4) into biologically-active T(3) and biologically-inactive rT(3), respectively. In several seasonally-breeding vertebrates, DIO2 and DIO3 expression is implicated in photoperiod signal transduction in adulthood. These experiments tested the hypothesis that juvenile Siberian hamsters, which are highly responsive to photoperiod at weaning (postnatal day [PND]18), exhibit rapid and sustained changes in hypothalamic dio3 mRNA expression during photoperiod-induced and photoperiod-inhibited puberty. Hypothalamic dio2 and dio3 expression was measured via quantitative PCR in hamsters born and reared in a long-day photoperiod (15L:9D) and weaned on PND18 into short-day photoperiods (9L:15D). In SD males, hypothalamic dio3 mRNA was elevated 2.5-fold within 3 days (PND21) and continued to increase (>20-fold) through PND32; changes in dio3 mRNA preceded inhibition of gonadotropin (FSH) secretion and gonadal regression in SD. Females exhibited comparable dio3 responses to SD. In LD males, dio3 remained low and invariant from PND18-PND32. In contrast, dio2 mRNA rose conspicuously on PND21, independent of photoperiod, returning to basal levels thereafter. In LD, a single afternoon melatonin (MEL) injection on PND18 or PND20 was sufficient to increase hypothalamic dio3 mRNA, and dio3 increased in proportion to the number of successive days of MEL treatment. SD photoperiods and MEL exert rapid, sustained, and additive effects on hypothalamic dio3 mRNA, which may play a central role in inhibiting maturation of the peripubertal hypothalamo-pituitary-gonadal axis.

  3. Bi-directional actions of dehydroepiandrosterone and aggression in female Siberian hamsters.

    PubMed

    Rendon, Nikki M; Demas, Gregory E

    2016-02-01

    There is a well-established positive relationship between gonadal steroids and aggression. In some seasonally breeding species, however, aggression often persists or is increased during short "winter-like" days when the gonads are regressed and circulating levels of gonadal steroids are relatively low. Although the mechanisms underlying short-day increases in aggression are not fully known, the adrenal androgen dehydroepiandrosterone (DHEA) has been suggested as an alternative neuroendocrine mechanism regulating seasonal aggression. We used two complementary experimental approaches to examine the bi-directional actions of DHEA and aggression in female Siberian hamsters, a seasonal rodent that displays increased aggression concomitant with elevated circulating DHEA in short days. In Experiment 1, we examined the effects of aggressive interactions on DHEA concentrations before and after an aggressive encounter in long- and short-day hamsters. Serum DHEA was altered in a photoperiod-dependent manner, with decreased DHEA levels in response to aggression in short- but not long-day hamsters. Next, we experimentally induced adrenal DHEA release via injections of exogenous ACTH and assessed changes in aggressive behavior across photoperiods. We show a robust increase in aggression in short compared with long days during baseline aggression trials; however, aggression was not significantly increased further in response to ACTH in either photoperiod during post-ACTH aggression trials. These findings suggest that DHEA plays a role in the regulation of short-day aggression, while also highlighting the need for additional studies addressing the causal relationship between DHEA and aggression in this and others species.

  4. Effect of season on seminal traits and serum hormone concentrations in captive male Siberian tigers (Panthera tigris).

    PubMed

    Byers, A P; Hunter, A G; Seal, U S; Graham, E F; Tilson, R L

    1990-09-01

    Electroejaculates and serum samples were collected throughout the year from 5 male Siberian tigers. Semen quality, seminal plasma chemistry and serum hormone concentrations were evaluated and analysed as a function of season. Semen volume, concentration, motility, viability and morphology were not influenced by season. The ability of spermatozoa to undergo capacitation and penetrate zona-free hamster eggs did not differ due to season. Season had no influence on seminal plasma concentrations of acid phosphatase, calcium, glucose, potassium and phosphorus. Serum values of thyroxine and triiodothyronine were lowest (P = 0.002 and P = 0.03, respectively) during the summer months while cortisol showed no seasonal variation. Serum testosterone concentrations were higher in fall and early winter (P less than 0.001) than at other times of the year but were not correlated with semen quality. These results demonstrate that season has no effect on the semen production and quality of captive male Siberian tigers.

  5. Twice daily melatonin peaks in Siberian but not Syrian hamsters under 24 h light:dark:light:dark cycles.

    PubMed

    Raiewski, Evan E; Elliott, Jeffrey A; Evans, Jennifer A; Glickman, Gena L; Gorman, Michael R

    2012-11-01

    The daily pattern of blood-borne melatonin varies seasonally under the control of a multi-oscillator circadian pacemaker. Here we examine patterns of melatonin secretion and locomotor activity in Siberian and Syrian hamsters entrained to bimodal LDLD8:4:8:4 and LD20:4 lighting schedules that facilitate novel temporal arrangements of component circadian oscillators. Under LDLD, both species robustly bifurcated wheel-running activity in distinct day scotophase (DS) and night scotophase (NS) bouts. Siberian hamsters displayed significant melatonin increases during each scotophase in LDLD, and in the single daily scotophase of LD20:4. The bimodal melatonin secretion pattern persisted in acutely extended 16 h scotophases. Syrian hamsters, in contrast, showed no significant increases in plasma melatonin during either scotophase of LDLD8:4:8:4 or in LD20:4. In this species, detectable levels were observed only when the DS of LDLD was acutely extended to yield 16 h of darkness. Established species differences in the phase lag of nocturnal melatonin secretion relative to activity onset may underlie the above contrast: In non-bifurcated entrainment to 24 h LD cycles, Siberian hamsters show increased melatonin secretion within ≈ 2 h after activity onset, whereas in Syrian hamsters, detectable melatonin secretion phase lags activity onset and the L/D transition by at least 4 h. The present results provide new evidence indicating multi-oscillator regulation of the waveform of melatonin secretion, specifically, the circadian control of the onset, offset and duration of nocturnal secretion.

  6. Agouti-related protein increases food hoarding more than food intake in Siberian hamsters.

    PubMed

    Day, Diane E; Bartness, Timothy J

    2004-01-01

    Agouti-related protein (AgRP), an endogenous melanocortin 3/4 receptor antagonist, appears to play an important role in the control of food intake and energy balance because exogenous administration in rats and overexpression in mice result in hyperphagia and body mass gain. Furthermore, arcuate nucleus AgRP mRNA is increased with fasting in laboratory rats and mice and is decreased with refeeding. In Siberian hamsters, fasting also increases arcuate nucleus AgRP mRNA, but these animals increase food hoarding, rather than food intake with refeeding. Therefore, we tested whether exogenous AgRP increased food hoarding in this species. Hamsters were trained in a hoarding/foraging apparatus to run a programmed number of wheel revolutions to earn food pellets. Four doses of AgRP-(83-132) or vehicle were injected into the third ventricle at the beginning of the dark phase, and food hoarding, food intake, and foraging were measured at various time points subsequently. Overall, food hoarding was stimulated as much as 10 times more than food intake, and both responses occurred as early as 1 h after injection. Food hoarding was increased the greatest at the lowest dose (0.1 nmol), whereas food intake was increased the greatest at the second lowest dose (1 nmol). Food intake and especially food hoarding were increased up to seven days after the AgRP injections. Foraging was increased at all AgRP doses except the highest dose (100 nmol). These results suggest that AgRP triggers the search for food in this species, and once they find it, hoarding predominates over eating.

  7. An odorant-binding protein as a new allergen from Siberian hamster (Phodopus sungorus).

    PubMed

    Torres, J A; Pastor-Vargas, C; de las Heras, M; Vivanco, F; Cuesta, Javier; Sastre, J

    2012-01-01

    A case of anaphylaxis following a bite from a Siberian hamster (SH; Phodopus sungorus) is described. Skin prick tests with hair, urine and salivary gland extracts from SH were positive, while the tests were negative for hair extracts from other rodents. IgE immunoblotting with the patient serum revealed 3 IgE-binding bands of about 18, 21 and 23 kDa. When the patient's serum was preincubated with rabbit, mouse and gerbil hair extracts, no inhibition of the 3 SH IgE-binding bands was demonstrated. Proteins extracted from the 3 bands were analyzed by N-terminal sequencing and matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry, and peptides were sequenced. IgE-binding bands were identified as being an odorant-binding protein belonging to the lipocalin family. Analysis of the 3 IgE-binding bands found in the hair, urine and salivary glands of SH showed a new allergenic protein lacking cross-reactivity with allergens from other rodents. The 3 bands likely correspond to isoforms of a single allergen. Copyright © 2011 S. Karger AG, Basel.

  8. Thermal acclimation and nutritional history affect the oxidation of different classes of exogenous nutrients in Siberian hamsters, Phodopus sungorus.

    PubMed

    McCue, Marshall D; Voigt, Christian C; Jefimow, Małgorzata; Wojciechowski, Michał S

    2014-11-01

    During acclimatization to winter, changes in morphology and physiology combined with changes in diet may affect how animals use the nutrients they ingest. To study (a) how thermal acclimation and (b) nutritional history affect the rates at which Siberian hamsters (Phodopus sungorus) oxidize different classes of dietary nutrients, we conducted two trials in which we fed hamsters one of three (13) C-labeled compounds, that is, glucose, leucine, or palmitic acid. We predicted that under acute cold stress (3 hr at 2°C) hamsters previously acclimated to cold temperatures (10°C) for 3 weeks would have higher resting metabolic rate (RMR) and would oxidize a greater proportion of dietary fatty acids than animals acclimated to 21°C. We also investigated how chronic nutritional stress affects how hamsters use dietary nutrients. To examine this, hamsters were fed four different diets (control, low protein, low lipid, and low-glycemic index) for 2 weeks. During cold challenges, hamsters previously acclimated to cold exhibited higher thermal conductance and RMR, and also oxidized more exogenous palmitic acid during the postprandial phase than animals acclimated to 21°C. In the nutritional stress trial, hamsters fed the low protein diet oxidized more exogenous glucose, but not more exogenous palmitic acid than the control group. The use of (13) C-labeled metabolic tracers combined with breath testing demonstrated that both thermal and nutritional history results in significant changes in the extent to which animals oxidize dietary nutrients during the postprandial period. © 2014 Wiley Periodicals, Inc.

  9. Light at night alters daily patterns of cortisol and clock proteins in female Siberian hamsters.

    PubMed

    Bedrosian, T A; Galan, A; Vaughn, C A; Weil, Z M; Nelson, R J

    2013-06-01

    Humans and other organisms have adapted to a 24-h solar cycle in response to life on Earth. The rotation of the planet on its axis and its revolution around the sun cause predictable daily and seasonal patterns in day length. To successfully anticipate and adapt to these patterns in the environment, a variety of biological processes oscillate with a daily rhythm of approximately 24 h in length. These rhythms arise from hierarchally-coupled cellular clocks generated by positive and negative transcription factors of core circadian clock gene expression. From these endogenous cellular clocks, overt rhythms in activity and patterns in hormone secretion and other homeostatic processes emerge. These circadian rhythms in physiology and behaviour can be organised by a variety of cues, although they are most potently entrained by light. In recent history, there has been a major change from naturally-occurring light cycles set by the sun, to artificial and sometimes erratic light cycles determined by the use of electric lighting. Virtually every individual living in an industrialised country experiences light at night (LAN) but, despite its prevalence, the biological effects of such unnatural lighting have not been fully considered. Using female Siberian hamsters (Phodopus sungorus), we investigated the effects of chronic nightly exposure to dim light on daily rhythms in locomotor activity, serum cortisol concentrations and brain expression of circadian clock proteins (i.e. PER1, PER2, BMAL1). Although locomotor activity remained entrained to the light cycle, the diurnal fluctuation of cortisol concentrations was blunted and the expression patterns of clock proteins in the suprachiasmatic nucleus and hippocampus were altered. These results demonstrate that chronic exposure to dim LAN can dramatically affect fundamental cellular function and emergent physiology.

  10. Fertility of a spontaneous hexaploid male Siberian sturgeon, Acipenser baerii

    PubMed Central

    2014-01-01

    Background Evolution of sturgeons and paddlefishes (order Acipenseriformes) is inherently connected with polyploidization events which resulted in differentiation of ploidy levels and chromosome numbers of present acipenseriform species. Moreover, allopolyploidization as well as autopolyploidization seems to be an ongoing process in these fishes and individuals with abnormal ploidy levels were occasionally observed within sturgeon populations. Here, we reported occurrence of Siberian sturgeon (Acipenser baerii) male with abnormal ploidy level for this species, accessed its ploidy level and chromosome number and investigate its potential sterility or fertility in comparison with normal individuals of sterlet (A. ruthenus), Russian sturgeon (A. gueldenstaedtii) and Siberian sturgeon (A. baerii). Results Acipenser ruthenus possessed 120 chromosomes, exhibiting recent diploidy (2n), A. gueldenstaedtii and A. baerii had ~245 chromosomes representing recent tetraploidy (4n), and A. baerii male with abnormal ploidy level had ~ 368 chromosomes, indicating recent hexaploidy (6n). Genealogy assessed from the mtDNA control region did not reveal genome markers of other sturgeon species and this individual was supposed to originate from spontaneous 1.5 fold increment in number of chromosome sets with respect to the number most frequently found in nature for this species. Following hormone stimulation, the spontaneous hexaploid male produced normal sperm with ability for fertilization. Fertilization of A. baerii and A. gueldenstaedtii ova from normal 4n level females with sperm of the hexaploid male produced viable, non-malformed pentaploid (5n) progeny with a ploidy level intermediate to those of the parents. Conclusion This study firstly described occurrence of hexaploid individual of A. baerii and confirmed its autopolyploid origin. In addition to that, the first detailed evidence about fertility of spontaneous hexaploid sturgeon was provided. If 1.5 fold increment in

  11. Photoperiod affects the diurnal rhythm of hippocampal neuronal morphology of Siberian hamsters.

    PubMed

    Ikeno, Tomoko; Weil, Zachary M; Nelson, Randy J

    2013-11-01

    Individuals of many species can regulate their physiology, morphology, and behavior in response to annual changes of day length (photoperiod). In mammals, the photoperiodic signal is mediated by a change in the duration of melatonin, leading to alterations in gene expressions, neuronal circuits, and hormonal secretion. The hippocampus is one of the most plastic structures in the adult brain and hippocampal neuronal morphology displays photoperiod-induced differences. Because the hippocampus is important for emotional and cognitive behaviors, photoperiod-driven remodeling of hippocampal neurons is implicated in seasonal differences of affect, including seasonal affective disorder (SAD) in humans. Because neuronal architecture is also affected by the day-night cycle in several brain areas, we hypothesized that hippocampal neuronal morphology would display a diurnal rhythm and that day length would influence that rhythm. In the present study, we examined diurnal and seasonal differences in hippocampal neuronal morphology, as well as mRNA expression of the neurotrophic factors (i.e., brain-derived neurotrophic factor [Bdnf], tropomyosin receptor kinase B [trkB; a receptor for BDNF], and vascular endothelial growth factor [Vegf]) and a circadian clock gene, Bmal1, in the hippocampus of Siberian hamsters. Diurnal rhythms in total length of dendrites, the number of primary dendrites, dendritic complexity, and distance of the furthest intersection from the cell body were observed only in long-day animals; however, diurnal rhythms in the number of branch points and mean length of segments were observed only in short-day animals. Spine density of dendrites displayed diurnal rhythmicity with different peak times between the CA1 and DG subregions and between long and short days. These results indicate that photoperiod affects daily morphological changes of hippocampal neurons and the daily rhythm of spine density, suggesting the possibility that photoperiod-induced adjustments

  12. Photoperiodic regulation of glycogen metabolism, glycolysis, and glutamine synthesis in tanycytes of the Siberian hamster suggests novel roles of tanycytes in hypothalamic function.

    PubMed

    Nilaweera, Kanishka; Herwig, Annika; Bolborea, Matei; Campbell, Gill; Mayer, Claus D; Morgan, Peter J; Ebling, Francis J P; Barrett, Perry

    2011-11-01

    The objective of this study is to investigate the impact of photoperiod on the temporal and spatial expression of genes involved in glucose metabolism in the brain of the seasonal mammal Phodopus sungorus (Siberian hamster). In situ hybridization was performed on brain sections obtained from male hamsters held in long photoperiod (high body weight and developed testes) or short photoperiod (reduced body weight with testicular regression). This analysis revealed upregulation in expression of genes involved in glycogen and glucose metabolism in short photoperiod and localized to the tanycyte layer of the third ventricle. On the basis of these data and a previously identified photoperiod-dependent increase in activity of neighboring hypothalamic neurons, we hypothesized that the observed expression changes may reflect alteration in either metabolic fuel or precursor neurotransmitter supply to surrounding neurons. Gene expression analysis was performed for genes involved in lactate and glutamate transport. This analysis showed that the gene for the lactate transporter MCT2 and glutamate transporter GLAST was decreased in the tanycyte layer in short photoperiod. Expression of mRNA for glutamine synthetase, the final enzyme in the synthesis of the neuronal neurotransmitter precursor, glutamine, was also decreased in short photoperiod. These data suggest a role for tanycytes in modulating glutamate concentrations and neurotransmitter supply in the hypothalamic environment. Copyright © 2011 Wiley-Liss, Inc.

  13. Effects of 60 Hz Magnetic Field Exposure on the Pineal and Hypothalamic-Pituitary-Gonadal Axis in the Siberian Hamster (Phodopus Sungorus)

    SciTech Connect

    Wilson, Bary W. ); Matt, Kathleen S.; Morris, James E. ); Sasser, Lyle B. ); Miller, Douglas L. ); Anderson, Larry E. )

    1999-11-15

    Experiments using the dwarf Siberian hamster Phodopus sungorus were carried out to determine possible neuroendocrine consequences of one-time and repeated exposures to 60 Hz magnetic fields (MF). Animals were maintained in either a short-light (SL, 8 h light:16 h dar) or long-light (LL, 16 h light:8h dark) photoperiod.

  14. Photoperiod-dependent regulation of carboxypeptidase E affects the selective processing of neuropeptides in the seasonal Siberian hamster (Phodopus sungorus).

    PubMed

    Helwig, M; Herwig, A; Heldmaier, G; Barrett, P; Mercer, J G; Klingenspor, M

    2013-02-01

    The production of bioactive peptides from biologically inactive precursors involves extensive post-translational processing, including enzymatic cleavage by proteolytic peptidases. Endoproteolytic prohormone-convertases initially cleave the precursors of many neuropeptides at specific amino acid sequences to generate intermediates with basic amino acid extensions on their C-termini. Subsequently, the related exopeptidases, carboxypeptidases D and E (CPD and CPE), are responsible for removing these amino acids before the peptides achieve biological activity. We investigated the effect of photoperiod on the processing of the neuropeptide precursor pro-opiomelanocortin (POMC) and its derived neuropeptides, α-melanocyte-stimulating hormone (MSH) and β-endorphin (END), within the hypothalamus of the seasonal Siberian hamster (Phodopus sungorus). We thus compared hypothalamic distribution of CPD, CPE, α-MSH and β-END using immunohistochemistry and measured the enzyme activity of CPE and concentrations of C-terminally cleaved α-MSH in short-day (SD; 8 : 16 h light/dark) and long-day (LD; 16 : 8 h light/dark) acclimatised hamsters. Increased immunoreactivity (-IR) of CPE, as well as higher CPE activity, was observed in SD. This increase was accompanied by more β-END-IR cells and substantially higher levels of C- terminally cleaved α-MSH, as determined by radioimmunoassay. Our results suggest that exoproteolytic cleavage of POMC-derived neuropeptides is tightly regulated by photoperiod in the Siberian hamster. Higher levels of biological active α-MSH- and β-END in SD are consistent with the hypothesis that post-translational processing is a key event in the regulation of seasonal energy balance. © 2012 British Society for Neuroendocrinology.

  15. Phenotypic flexibility of energetics in acclimated Siberian hamsters has a narrower scope in winter than in summer.

    PubMed

    Boratyński, Jan S; Jefimow, Małgorzata; Wojciechowski, Michał S

    2016-04-01

    As photoperiod shortens with the approach of winter, small mammals should reduce their energy expenditure to survive periods of food limitation. However, within seasons, animals should balance their energy budgets as abiotic conditions change, sometimes unpredictably; cold spells should increase heat production, while warm spells should do the opposite. Therefore, we addressed specific questions about the possible interactions between seasonal acclimatization and the intra-seasonal phenotypic flexibility of metabolic rate. We hypothesized that phenotypic flexibility in small mammals differs seasonally and is greater in summer than in winter, and predicted that seasonal adjustments in energetics, which are driven by photoperiod, overwhelm the influence of variations in the thermal environment. We measured body mass, basal metabolic rate (BMR), facultative non-shivering thermogenesis (fNST), body temperature, and calculated minimum thermal conductance in Siberian hamsters Phodopus sungorus. Animals were acclimated to winter-like, and then to summer-like conditions and, within each season, were exposed twice, for 3 weeks to 10, 20 or 28 °C. We used differences between values measured after these short acclimation periods as a measure of the scope of phenotypic flexibility. After winter acclimation, hamsters were lighter, had lower whole animal BMR, higher fNST than in summer, and developed heterothermy. After these short acclimations to the above-mentioned temperatures, hamsters showed reversible changes in BMR and fNST; however, these traits were less flexible in winter than in summer. We conclude that seasonal acclimation affects hamster responses to intra-seasonal variations in the thermal environment. We argue that understanding seasonal changes in phenotypic flexibility is crucial for predicting the biological consequences of global climate changes.

  16. Exogenous T₃ elicits long day-like alterations in testis size and the RFamides Kisspeptin and gonadotropin-inhibitory hormone in short-day Siberian hamsters.

    PubMed

    Henson, Jerad R; Carter, Sara N; Freeman, David A

    2013-06-01

    Siberian hamsters (Phodopus sungorus) exhibit robust seasonal rhythms of reproduction driven by changes in day length. Day length is encoded endogenously by the duration of nocturnal melatonin (Mel) secretion from the pineal gland. Short duration Mel signals stimulate whereas long duration Mel signals inhibit reproduction. The mechanism by which Mel regulates the reproductive axis has not been fully characterized. In Siberian hamsters, the thyroid hormone triiodothyronine (T₃) is thought to be part of the photoperiodic mechanism. The availability of T₃ is decreased in hamsters housed in short day lengths, and injections of exogenous T₃ stimulate testicular growth in short-day (SD) Siberian hamsters. Thus, T₃ acts as a neuroendocrine intermediate between the Mel rhythm and the reproductive axis. The RFamides kisspeptin (Kiss1) and gonadotropin-inhibitory hormone (GnIH) also act as a link between the Mel rhythm and the reproductive axis. Expression of both of these neuropeptides is regulated by photoperiod and Mel. Kiss1 stimulates, and GnIH inhibits, the reproductive axis in long-day housed hamsters. It remains unknown whether T₃ acts through changes in RFamide expression in the regulation of reproduction or whether these molecules act independently of one another. We tested the hypothesis that exogenous T₃ administered to SD hamsters, a treatment that stimulates testicular growth, would also result in alterations in the patterns of Kiss1- and GnIH-immunoreactivity. Administration of T₃ to SD hamsters resulted in significant testicular growth as well as a long day-like pattern of RFamide peptide expression. Thus, exogenous T₃ elicited increased numbers of Kiss1-positive cells in the hypothalamic anteroventral periventricular nucleus, decreased numbers of Kiss1-positive cells in the arcuate nucleus, and a greater number of GnIH-positive cells in the dorsomedial hypothalamus compared with SD controls. The results are consistent with the hypothesis that

  17. Voluntary exercise increases gonadotropin secretion in male Golden hamsters.

    PubMed

    Pieper, D R; Ali, H Y; Benson, L L; Shows, M D; Lobocki, C A; Subramanian, M G

    1995-07-01

    To determine the effect of voluntary exercise and food restriction on reproductive hormone secretion, 48 adult male hamsters were placed in cages with (EX) or without (SED) running wheels. One-half of the animals in each exercise group was fed ad libitum, and the other half was food restricted to reduce their body weight to 90 g over 4 wk. After 10 wk, the EX ad libitum-fed group had much larger testes and much higher serum follicle-stimulating hormone and testosterone levels than the other three groups, but these values in the EX food-restricted hamsters were similar to those in the SED food-restricted group. In experiment 2, 20 adult male hamsters were castrated and later implanted with silicone rubber capsules containing testosterone. Two weeks after implantation of the capsules, the serum follicle-stimulating hormone levels were higher in the EX than in the SED group of testosterone-treated hamsters, but not in animals receiving blank capsules. These data suggest that exercise increases gonadotropin secretion by inhibiting the negative feedback of testosterone.

  18. Conserved Expression of the Glutamate NMDA Receptor 1 Subunit Splice Variants during the Development of the Siberian Hamster Suprachiasmatic Nucleus

    PubMed Central

    Duffield, Giles E.; Mikkelsen, Jens D.; Ebling, Francis J. P.

    2012-01-01

    Glutamate neurotransmission and the N-methyl-D-aspartate receptor (NMDAR) are central to photic signaling to the master circadian pacemaker located in the hypothalamic suprachiasmatic nucleus (SCN). NMDARs also play important roles in brain development including visual input circuits. The functional NMDAR is comprised of multiple subunits, but each requiring the NR1 subunit for normal activity. The NR1 can be alternatively spliced to produce isoforms that confer different functional properties on the NMDAR. The SCN undergoes extensive developmental changes during postnatal life, including synaptogenesis and acquisition of photic signaling. These changes are especially important in the highly photoperiodic Siberian hamster, in which development of sensitivity to photic cues within the SCN could impact early physiological programming. In this study we examined the expression of NR1 isoforms in the hamster at different developmental ages. Gene expression in the forebrain was quantified by in situ hybridization using oligonucleotide probes specific to alternatively spliced regions of the NR1 heteronuclear mRNA, including examination of anterior hypothalamus, piriform cortex, caudate-putamen, thalamus and hippocampus. Gene expression analysis within the SCN revealed the absence of the N1 cassette, the presence of the C2 cassette alone and the combined absence of C1 and C2 cassettes, indicating that the dominant splice variants are NR1-2a and NR1-4a. Whilst we observe changes at different developmental ages in levels of NR1 isoform probe hybridization in various forebrain structures, we find no significant changes within the SCN. This suggests that a switch in NR1 isoform does not underlie or is not produced by developmental changes within the hamster SCN. Consistency of the NR1 isoforms would ensure that the response of the SCN cells to photic signals remains stable throughout life, an important aspect of the function of the SCN as a responder to environmental changes

  19. Diurnal profiles of hypothalamic energy balance gene expression with photoperiod manipulation in the Siberian hamster, Phodopus sungorus.

    PubMed

    Ellis, Claire; Moar, Kim M; Logie, Tracy J; Ross, Alexander W; Morgan, Peter J; Mercer, Julian G

    2008-04-01

    Hypothalamic energy balance genes have been examined in the context of seasonal body weight regulation in the Siberian hamster. Most of these long photoperiod (LD)/short photoperiod (SD) comparisons have been of tissues collected at a single point in the light-dark cycle. We examined the diurnal expression profile of hypothalamic genes in hamsters killed at 3-h intervals throughout the light-dark cycle after housing in LD or SD for 12 wk. Gene expression of neuropeptide Y, agouti-related peptide, proopiomelanocortin, cocaine- and amphetamine-regulated transcript, long-form leptin receptor, suppressor of cytokine signaling-3, melanocortin-3 receptor, melanocortin-4 receptor, and the clock gene Per1 as control were measured by in situ hybridization in hypothalamic nuclei. Effects of photoperiod on gene expression and leptin levels were generally consistent with previous reports. A clear diurnal variation was observed for Per1 in the suprachiasmatic nucleus in both photoperiods. Temporal effects on expression of energy balance genes were restricted to long-form leptin receptor in the arcuate nucleus and ventromedial nucleus, where similar diurnal expression profiles were observed, and melanocortin-4 receptor in the paraventricular nucleus; these effects were only observed in LD hamsters. There was no variation in serum leptin concentration. The 24-h profiles of hypothalamic energy balance gene expression broadly confirm photoperiodic differences that were observed previously, based on single time point comparisons, support the growing consensus that these genes have a limited role in seasonal body weight regulation, and further suggest limited involvement in daily rhythms of food intake.

  20. The role of histamine 3 receptors in the control of food intake in a seasonal model of obesity: the Siberian hamster.

    PubMed

    Jethwa, Preeti H; Barrett, Perry; Turnbull, Yvonne; Enright, Rachel A; Warner, Amy; Murphy, Michelle; Ebling, Francis J P

    2009-03-01

    Siberian hamsters develop hypophagia and increase catabolism of fat reserves in response to short photoperiods resulting in a natural loss of body weight in winter. We previously found that histamine 3 receptor (H3R) mRNA in the posterior hypothalamus is significantly decreased in short photoperiods. We hypothesized that this lower expression of H3R might contribute to the winter hypophagic state, therefore we examined the effects of the H3R agonist imetit and inverse agonists clobenpropit and thioperamide on food intake. We expressed the Siberian hamster H3R receptor in vitro and confirmed that imetit, clobenpropit and thioperamide are bound specifically, thus validating them as tools to investigate the role of H3R in vivo. Intracerebroventricular administration of histamine decreased food intake in hamsters in the fat summer state. Administration of imetit to hamsters in the lean state increased food intake, whereas administration of inverse agonists decreased food intake, though this was associated with decreased locomotor activity. Both H3R inverse agonists prevented the nocturnal rise in body temperature indicating additional effects on energy expenditure. In summary, our results suggest that increased availability of central histamine or the reduction of H3R activity decrease food intake. These effects are similar to those observed in hamsters in short photoperiods.

  1. Interactions with heterospecific males do not affect how female Mesocricetus hamsters respond to conspecific males

    PubMed Central

    delBarco-Trillo, Javier; Johnston, Robert E.

    2012-01-01

    Reproductive interference includes any interspecific interaction that reduces the fitness of one or both species involved. There are several types of reproductive interference, but they normally involve the direct cost of interacting or mating with heterospecifics. An indirect cost of interacting with heterospecific individuals is a consequent reduction in successful interactions with conspecifics. We tested the hypothesis that being aggressive towards a heterospecific individual will diminish sexual responses towards conspecifics in later encounters. We used two species of Mesocricetus hamsters (Syrian and Turkish hamsters), whose interspecific interactions have previously been determined. We exposed or both exposed and paired Syrian hamster females with a conspecific or a heterospecific male. Five minutes later, we paired all females with a conspecific male and measured the latency to lordosis, the duration of lordosis and any incidence of aggression. We found that (1) interactions with heterospecific males did not affect how females responded to conspecific males in later encounters and (2) previous pairing of female subjects with either conspecific or heterospecific males promoted a faster sexual response by females in subsequent interactions with conspecific males. Thus, aggressive interactions of Syrian hamster females with heterospecific males, contrary to our initial hypothesis, had a positive effect on subsequent interactions with conspecific males. PMID:23439800

  2. Photoperiod regulates multiple gene expression in the suprachiasmatic nuclei and pars tuberalis of the Siberian hamster (Phodopus sungorus).

    PubMed

    Johnston, Jonathan D; Ebling, Francis J P; Hazlerigg, David G

    2005-06-01

    Photoperiod regulates the seasonal physiology of many mammals living in temperate latitudes. Photoperiodic information is decoded by the master circadian clock in the suprachiasmatic nuclei (SCN) of the hypothalamus and then transduced via pineal melatonin secretion. This neurochemical signal is interpreted by tissues expressing melatonin receptors (e.g. the pituitary pars tuberalis, PT) to drive physiological changes. In this study we analysed the photoperiodic regulation of the circadian clockwork in the SCN and PT of the Siberian hamster. Female hamsters were exposed to either long or short photoperiod for 8 weeks and sampled at 2-h intervals across the 24-h cycle. In the SCN, rhythmic expression of the clock genes Per1, Per2, Cry1, Rev-erbalpha, and the clock-controlled genes arginine vasopressin (AVP) and d-element binding protein (DBP) was modulated by photoperiod. All of these E-box-containing genes tracked dawn, with earlier peak mRNA expression in long, compared to short, photoperiod. This response occurred irrespective of the presence of additional regulatory cis-elements, suggesting photoperiodic regulation of SCN gene expression through a common E-box-related mechanism. In long photoperiod, expression of Cry1 and Per1 in the PT tracked the onset and offset of melatonin secretion, respectively. However, whereas Cry1 tracked melatonin onset in short period, Per1 expression was not detectably rhythmic. We therefore propose that, in the SCN, photoperiodic regulation of clock gene expression primarily occurs via E-boxes, whereas melatonin-driven signal transduction drives the phasing of a subset of clock genes in the PT, independently of the E-box.

  3. A magnetic field effect on learning in male golden hamsters.

    PubMed

    Łopuch, Sylwia

    2009-05-01

    The aim of this experiment was to investigate the influence of repeated exposure to 10, 20, 30 or 40 Hz magnetic fields at 0.1T on the learning of male golden hamsters in a Skinner box, in which the animals learned to press a lever to receive a food reward. The latency of the first response was not affected by exposure to the magnetic fields used in this experiment. No significant field-dependent effects on the performance of the task were observed in males exposed to 10 and 20 Hz magnetic fields at 0.1T. However, exposure significantly improved the learning of the task in animals exposed to 30 and 40 Hz magnetic fields at 0.1T.

  4. Effects of cold exposure, exogenous melatonin and short-day treatment on the weight-regulation and body temperature of the Siberian hamster (Phodopus sungorus).

    PubMed

    Korhonen, Tuula; Mustonen, Anne-Mari; Nieminen, Petteri; Saarela, Seppo

    2008-08-07

    To investigate how winter acclimatization (WA), exogenous melatonin (MEL) or endogenous melatonin (SD) affect plasma leptin and ghrelin concentrations and how leptin and ghrelin contribute to the regulation of different adaptations to wintering in the Siberian hamster. The plasma leptin and insulin and testicular testosterone concentrations were lower in the WA, MEL and SD groups, whereas the plasma ghrelin concentration was higher due to the WA treatment. In the treated hamsters, body temperatures during photo- and scotophase were lower throughout the study and torpor bouts were observed. The absolute and relative body fat masses were lower in all treated groups. Siberian hamsters reduce their feeding in winter, although just the opposite is suggested by the lower leptin concentrations in all treated groups and the higher ghrelin concentration in the WA group. The positive correlation between plasma leptin and testicular testosterone indicates a possible interaction between them. Torpor bouts were related to a lowered body mass and plasma leptin concentration. Exposure to short photoperiod did not induce elevated plasma ghrelin levels; the response required a low ambient temperature together with short day length.

  5. Mitochondrial metabolism during daily torpor in the dwarf Siberian hamster: role of active regulated changes and passive thermal effects.

    PubMed

    Brown, Jason C L; Gerson, Alexander R; Staples, James F

    2007-11-01

    During daily torpor in the dwarf Siberian hamster, Phodopus sungorus, metabolic rate is reduced by 65% compared with the basal rate, but the mechanisms involved are contentious. We examined liver mitochondrial respiration to determine the possible role of active regulated changes and passive thermal effects in the reduction of metabolic rate. When assayed at 37 degrees C, state 3 (phosphorylating) respiration, but not state 4 (nonphosphorylating) respiration, was significantly lower during torpor compared with normothermia, suggesting that active regulated changes occur during daily torpor. Using top-down elasticity analysis, we determined that these active changes in torpor included a reduced substrate oxidation capacity and an increased proton conductance of the inner mitochondrial membrane. At 15 degrees C, mitochondrial respiration was at least 75% lower than at 37 degrees C, but there was no difference between normothermia and torpor. This implies that the active regulated changes are likely more important for reducing respiration at high temperatures (i.e., during entrance) and/or have effects other than reducing respiration at low temperatures. The decrease in respiration from 37 degrees C to 15 degrees C resulted predominantly from a considerable reduction of substrate oxidation capacity in both torpid and normothermic animals. Temperature-dependent changes in proton leak and phosphorylation kinetics depended on metabolic state; proton leakiness increased in torpid animals but decreased in normothermic animals, whereas phosphorylation activity decreased in torpid animals but increased in normothermic animals. Overall, we have shown that both active and passive changes to oxidative phosphorylation occur during daily torpor in this species, contributing to reduced metabolic rate.

  6. Photoperiodic regulation of cellular retinol binding protein, CRBP1 [corrected] and nestin in tanycytes of the third ventricle ependymal layer of the Siberian hamster.

    PubMed

    Barrett, Perry; Ivanova, Elena; Graham, E Scott; Ross, Alexander W; Wilson, Dana; Plé, Helene; Mercer, Julian G; Ebling, Francis J; Schuhler, Sandrine; Dupré, Sandrine M; Loudon, Andrew; Morgan, Peter J

    2006-12-01

    Tanycytes in the ependymal layer of the third ventricle act both as a barrier and a communication gateway between the cerebrospinal fluid, brain and portal blood supply to the pituitary gland. However, the range, importance and mechanisms involved in the function of tanycytes remain to be explored. In this study, we have utilized a photoperiodic animal to examine the expression of three unrelated gene sequences in relation to photoperiod-induced changes in seasonal physiology and behaviour. We demonstrate that cellular retinol binding protein [corrected] (CRBP1), a retinoic acid transport protein, GPR50, an orphan G-protein-coupled receptor and nestin, an intermediate filament protein, are down-regulated in short-day photoperiods. The distribution of the three sequences is very similar, with expression located in cells with tanycyte morphology in the region of the ependymal layer where tanycytes are located. Furthermore, CRBP1 expression in the ependymal layer is shown to be independent of a circadian clock and altered testosterone levels associated with testicular regression in short photo-period. Pinealectomy of Siberian hamsters demonstrates CRBP1 expression is likely to be dependent on melatonin output from the pineal gland. This provides evidence that tanycytes are seasonally responsive cells and are likely to be an important part of the mechanism to facilitate seasonal physiology and behaviour in the Siberian hamster.

  7. Circadian Disruption Alters the Effects of Lipopolysaccharide Treatment on Circadian and Ultradian Locomotor Activity and Body Temperature Rhythms of Female Siberian Hamsters.

    PubMed

    Prendergast, Brian J; Cable, Erin J; Stevenson, Tyler J; Onishi, Kenneth G; Zucker, Irving; Kay, Leslie M

    2015-12-01

    The effect of circadian rhythm (CR) disruption on immune function depends on the method by which CRs are disrupted. Behavioral and thermoregulatory responses induced by lipopolysaccharide (LPS) treatment were assessed in female Siberian hamsters in which circadian locomotor activity (LMA) rhythms were eliminated by exposure to a disruptive phase-shifting protocol (DPS) that sustains arrhythmicity even when hamsters are housed in a light-dark cycle. This noninvasive treatment avoids genome manipulations and neurological damage associated with other models of CR disruption. Circadian rhythmic (RHYTH) and arrhythmic (ARR) hamsters housed in a 16L:8D photocycle were injected with bacterial LPS near the onset of the light (zeitgeber time 1; ZT1) or dark (ZT16) phase. LPS injections at ZT16 and ZT1 elicited febrile responses in both RHYTH and ARR hamsters, but the effect was attenuated in the arrhythmic females. In ZT16, LPS inhibited LMA in the dark phase immediately after injection but not on subsequent nights in both chronotypes; in contrast, LPS at ZT1 elicited more enduring (~4 day) locomotor hypoactivity in ARR than in RHYTH hamsters. Power and period of dark-phase ultradian rhythms (URs) in LMA and Tb were markedly altered by LPS treatment, as was the power in the circadian waveform. Disrupted circadian rhythms in this model system attenuated responses to LPS in a trait- and ZT-specific manner; changes in UR period and power are novel components of the acute-phase response to infection that may affect energy conservation. © 2015 The Author(s).

  8. Male Syrian Hamsters Demonstrate a Conditioned Place Preference for Sexual Behavior and Female Chemosensory Stimuli

    PubMed Central

    Bell, Margaret R.; Meerts, Sarah H.; Sisk, Cheryl L.

    2010-01-01

    Sexual behavior is a natural reward for many rodent species, and it often includes chemosensory-directed components. Chemosensory stimuli themselves may also be rewarding. Conditioned place preference (CPP) is one paradigm frequently used to test the rewarding properties of a range of stimuli. Males and females of several rodent species show a CPP for sexual behavior, however, it is currently unknown whether sexual behavior can induce a CPP in male Syrian hamsters. As male Syrian hamsters are an animal model commonly used for investigation of the neurobiology of sexual behavior, understanding the rewarding components of sexual stimuli will better direct future research on brain regions and neurotransmitters involved in these behaviors. Experiment 1 tested the prediction that male hamsters show a CPP for sexual behavior. Female chemosensory stimuli are essential for the display of sexual behavior in male hamsters, however, the rewarding properties of female chemosensory stimuli contained in vaginal secretions (VS) are uncertain. Therefore, Experiment 2 tested the prediction that male hamsters show a CPP for VS. This study is the first demonstration that both sexual behavior and VS induce a CPP in male hamsters. Thus, female chemosensory stimuli are a natural reward in a species that is dependent on these stimuli for reproductive fitness. PMID:20515693

  9. Male Syrian hamsters demonstrate a conditioned place preference for sexual behavior and female chemosensory stimuli.

    PubMed

    Bell, Margaret R; Meerts, Sarah H; Sisk, Cheryl L

    2010-08-01

    Sexual behavior is a natural reward for many rodent species, and it often includes chemosensory-directed components. Chemosensory stimuli themselves may also be rewarding. Conditioned place preference (CPP) is one paradigm frequently used to test the rewarding properties of a range of stimuli. Males and females of several rodent species show a CPP for sexual behavior; however, it is currently unknown whether sexual behavior can induce a CPP in male Syrian hamsters. As male Syrian hamsters are an animal model commonly used for investigation of the neurobiology of sexual behavior, understanding the rewarding components of sexual stimuli will better direct future research on brain regions and neurotransmitters involved in these behaviors. Experiment 1 tested the prediction that male hamsters show a CPP for sexual behavior. Female chemosensory stimuli are essential for the display of sexual behavior in male hamsters; however, the rewarding properties of female chemosensory stimuli contained in vaginal secretions (VS) are uncertain. Therefore, experiment 2 tested the prediction that male hamsters show a CPP for VS. This study is the first demonstration that both sexual behavior and VS induce a CPP in male hamsters. Thus, female chemosensory stimuli are a natural reward in a species that is dependent on these stimuli for reproductive fitness. Copyright 2010 Elsevier Inc. All rights reserved.

  10. Ventromedial hypothalamic mediation of photoperiodic gonadal responses in male Syrian hamsters.

    PubMed

    Bae, H H; Mangels, R A; Cho, B S; Dark, J; Yellon, S M; Zucker, I

    1999-10-01

    Short day lengths induce testicular regression in seasonally breeding Syrian hamsters. To test whether the ventromedial hypothalamus is necessary to maintain reproductive quiescence once testicular regression has been achieved, photoregressed male hamsters were subjected to lesions of the ventromedial hypothalamus (VMHx), pinealectomy (Pinx), or sham operation (Sham). VMHx hamsters underwent accelerated gonadal recrudescence compared to Pinx and Sham hamsters. Recovery of prolactin concentrations (PRL) to values characteristic of long-day hamsters was hastened in the VMHx animals compared to Sham hamsters. Concentrations of follicle stimulating hormone (FSH) increased prematurely in both the VMHx and Pinx animals, beginning a few weeks after surgery. By the time the gonads had undergone recrudescence and the hamsters were refractory to melatonin, PRL and FSH concentrations had returned to baseline long-day values in all groups; there was no evidence of hypersecretion of either hormone in any of the animals with lesions. Melatonin concentrations of VMHx hamsters did not differ from those of sham-operated animals, but because only a single determination was made, it remains possible that VMH damage altered the duration of nightly melatonin secretion. An intact VMH appears to be essential for the continued maintenance of reproductive suppression induced by exposure to short day lengths; these and earlier findings suggest that the VMH-dorsomedial hypothalamic complex mediates regression of the reproductive apparatus during decreasing day lengths of late summer and early autumn and also is necessary to sustain regression during the winter months.

  11. Male golden hamster in male reproductive toxicology testing: Assessment of protective activity of selenium in acute cadmium intoxication

    SciTech Connect

    Wiodarczyk, B.; Biernacki, B.; Minta, M.; Juszkiewicz, T.; Kozaczynski, W.

    1995-06-01

    The golden hamster has a short history as a laboratory animal. In spite of this, it has been extensively used as a subject for biomedical research. The hamster has also been utilized in toxicological evaluations, especially in teratology studies. Results of these investigations reveal that laboratory hamsters are very sensitive to many chemical compounds, including: drugs, food additives, industrial chemicals, heavy metals, and other environmental contaminants. The animals most frequently used in toxicological investigations are rats and mice. This is also true in male reproductive toxicology. Apparent differences in species sensitivity to chemical compounds suggest a need to examine a new species in this field of toxicology. A good example of chemical specific differences in species sensitivity is the testicular toxicity of 1,2-dibromo-3-chloropropane (DBCP), which was a testicular toxicant in humans and in rats, but it was not effective, even at relatively high dose levels, in the mouse. From our own vast experience in using hamsters in toxicological studies, we decided to use this laboratory animal in male reproductive toxicology screening tests. The purpose of this study was to determine the suitability of golden hamsters as an experimental animal species for male reproductive toxicology testing. To this effect we have chosen selenium and cadmium as test agents as they were well known for their spectacular effect on the male reproductive system. 13 refs., 1 tab.

  12. Adult female hamsters avoid interspecific mating after exposure to heterospecific males

    PubMed Central

    delBarco-Trillo, Javier; McPhee, M. E.; Johnston, Robert E.

    2010-01-01

    When females mate with a heterospecific male, they do not usually produce viable offspring. Thus, there is a selective pressure for females to avoid interspecific mating. In many species, females innately avoid heterospecific males; females can also imprint on their parents to avoid later sexual interactions with heterospecific males. However, it was previously unknown whether adult females can learn to discriminate against heterospecific males. We tested the hypothesis that adult females previously unable to avoid interspecific mating learn to avoid such mating after being exposed to heterospecific males. Syrian hamster (Mesocricetus auratus) females not previously exposed to Turkish hamster (Mesocricetus brandti) males can discriminate between odors of conspecific and heterospecific males, but they mate with either type of male. However, when we exposed adult females to both a conspecific male and a heterospecific male through wire-mesh barriers for 8 days, and then paired them sequentially with the two males, females were more receptive to conspecific males and more aggressive to heterospecific males. When females were paired with the heterospecific male first and the conspecific male second, no female was receptive and all were aggressive to heterospecific males. When females were paired with the conspecific male first, only 43% of females were then aggressive toward the heterospecific male. That is, interactions with conspecific males may decrease a female’s ability to properly avoid heterospecific males. Our study clearly shows for the first time that females can learn during adulthood to avoid interspecific mating just by being exposed to stimuli from heterospecific males. PMID:20676390

  13. Social defeat and footshock increase body mass and adiposity in male Syrian hamsters.

    PubMed

    Solomon, Matia B; Foster, Michelle T; Bartness, Timothy J; Huhman, Kim L

    2007-01-01

    Obesity is a world-wide epidemic, and many factors, including stress, have been linked to this growing trend. After social stress (i.e., defeat), subordinate laboratory rats and most laboratory mice become hypophagic and, subsequently, lose body mass; the opposite is true of subordinate Syrian hamsters. After social defeat, Syrian hamsters become hyperphagic and gain body mass compared with nonstressed controls. It is unknown whether this increase in body mass and food intake is limited to subordinate hamsters. In experiment 1, we asked, do dominant hamsters increase food intake, body mass, and adiposity after an agonistic encounter? Subordinate hamsters increased food intake and body mass compared with nonstressed controls. Although there was no difference in food intake or absolute body mass between dominant and nonstressed control animals, cumulative body mass gain was significantly higher in dominant than in nonstressed control animals. Total carcass lipid and white adipose tissue (WAT) (i.e., retroperitoneal and epididymal WAT) masses were significantly increased in subordinate, but not dominant, hamsters compared with nonstressed controls. In experiment 2, we asked, does footshock stress increase food intake, body mass, and adiposity. Hamsters exposed to defeat, but not footshock stress, increased food intake relative to nonstressed controls. In animals exposed to defeat or footshock stress, body mass, as well as mesenteric WAT mass, increased compared with nonstressed controls. Collectively, these data demonstrate that social and nonsocial stressors increase body and lipid mass in male hamsters, suggesting that this species may prove useful for studying the physiology of stress-induced obesity in some humans.

  14. 7 alpha-methyl-19-nortestosterone facilitates sexual behavior in the male Syrian hamster.

    PubMed

    Wood, R I; Bean, A R; Sundaram, K; Kumar, N; Bardin, C W

    1996-06-01

    Steroid hormones from the testes promote attraction to estrous females and facilitate copulation in the male Syrian hamster. We compared the ability of testosterone (T) and MENT, a potent synthetic androgen that does not undergo 5 alpha-reduction, to maintain sexual behavior in castrated males. Steroid treatment was initiated immediately after castration at three levels by means of Alzet osmotic pumps in sexually experienced adult male hamsters. Daily doses were 5, 25, or 100 micrograms T and 1, 5, or 25 micrograms MENT (n = 5/group). Additional castrated males (n = 5) remained untreated. Sexual behavior was recorded during two 10-min tests before, and at 2, 4, 6, and 8 weeks after orchidectomy. MENT and T maintained equivalent levels of behavior at each corresponding dose of androgen (high, medium, or low). The low dose of T or MENT failed to sustain mating behavior. Eight weeks after castration, males receiving the high and medium doses of androgens continued to express intromissions and ejaculations at gonadally intact levels. However, only males receiving the high dose showed anogenital investigation at the same level as intact males. From these data, we conclude that MENT sustains mating behavior in the male hamster, and that chemoinvestigatory behavior requires higher levels of androgens than those necessary for copulation.

  15. Short days and exogenous melatonin increase aggression of male Syrian hamsters (Mesocricetus auratus).

    PubMed

    Jasnow, Aaron M; Huhman, Kim L; Bartness, Timothy J; Demas, Gregory E

    2002-08-01

    Many nontropical rodent species rely on photoperiod as a primary cue to coordinate seasonally appropriate changes in physiology and behavior. Among these changes, some species of rodents demonstrate increased aggression in short, "winter-like" compared with long "summer-like" day lengths. The precise neuroendocrine mechanisms mediating changes in aggression, however, remain largely unknown. The goal of the present study was to examine the effects of photoperiod and exogenous melatonin on resident-intruder aggression in male Syrian hamsters (Mesocricetus auratus). In Experiment 1, male Syrian hamsters were housed in long (LD 14:10) or short (LD 10:14) days for 10 weeks. In Experiment 2, hamsters were housed in long days and half of the animals were given daily subcutaneous melatonin injections (15 microg/day in 0.1 ml saline) 2 h before lights out for 10 consecutive days to simulate a short-day pattern of melatonin secretion, while the remaining animals received injections of the vehicle alone. Animals in both experiments were then tested using a resident-intruder model of aggression and the number of attacks, duration of attacks, and latency to initial attack were recorded. In Experiment 1, short-day hamsters underwent gonadal regression and displayed increased aggression compared with long-day animals. In Experiment 2, melatonin treatment also increased aggression compared with control hamsters without affecting circulating testosterone. Collectively, the results of the present study demonstrate that exposure to short days or short day-like patterns of melatonin increase aggression in male Syrian hamsters. In addition, these results suggest that photoperiodic changes in aggression provide an important, ecologically relevant model with which to study the neuroendocrine mechanisms underlying aggression in rodents.

  16. Intraovarian expression of GnRH-1 and gonadotropin mRNA and protein levels in Siberian hamsters during the estrus cycle and photoperiod induced regression/recrudescence

    PubMed Central

    Shahed, Asha; Young, Kelly A.

    2010-01-01

    The hypothalamic-pituitary-gonadal (HPG) axis is the key reproductive regulator in vertebrates. While gonadotropin releasing hormone (GnRH), follicle stimulating (FSH), and luteinizing (LH) hormones are primarily produced in the hypothalamus and pituitary, they can be synthesized in the gonads, suggesting an intraovarian GnRH-gonadotropin axis. Because these hormones are critical for follicle maturation and steroidogenesis, we hypothesized that this intraovarian axis may be important in photoperiod-induced ovarian regression/recrudescence in seasonal breeders. Thus, we investigated GnRH-1 and gonadotropin mRNA and protein expression in Siberian hamster ovaries during (1) the estrous cycle; where ovaries from cycling long day hamsters (LD;16L:8D) were collected at proestrus, estrus, diestrus I, and diestrus II and (2) during photoperiod induced regression/ recrudescence; where ovaries were collected from hamsters exposed to 14wks of LD, short days (SD;8L:16D), or 8wks post-transfer to LD after 14wks SD (PT). GnRH-1, LHβ, FSHβ, and common α subunit mRNA expression was observed in cycling ovaries. GnRH-1 expression peaked at diestrus I compared to other stages (p<0.05). FSHβ and LHβ mRNA levels peaked at proestrus and diestrus I (p<0.05), with no change in the α subunit across the cycle (p>0.05). SD exposure decreased ovarian mass and plasma estradiol concentrations (p<0.05) and increased GnRH-1, LHβ, FSHβ, and α subunit mRNA expression as compared to LD and, except for LH, compared to PT (p<0.05). GnRH and gonadotropin protein was also dynamically expressed across the estrous cycle and photoperiod exposure. The presence of cycling intraovarian GnRH-1 and gonadotropin mRNA suggests that these hormones may be locally involved in ovarian maintenance during SD regression and/or could potentially serve to prime ovaries for rapid recrudescence. PMID:20955709

  17. Androgen and estradiol levels in plasma and amniotic fluid of late gestational male and female hamsters: uterine position effects.

    PubMed

    Vomachka, A J; Lisk, R D

    1986-06-01

    Using radioimmunoassay we have measured the plasma and amniotic fluid levels of androgen and estradiol in male and female hamster fetuses nearing parturition. On Days 14 and 15 of gestation (day of birth = Day 16), plasma levels of androgen are higher in males than females while estradiol levels are equal. Amniotic fluid levels of these hormones, while lower than plasma, reflect the difference in androgen and the similarity in estradiol between sexes. Uterine position analysis on Day 14 suggests that female siblings located caudally suppress amniotic fluid androgen and elevate estradiol levels of male siblings. Comparison of Day 18 gestation male and female rat amniotic fluid androgen to Day 14 hamsters reveals that male rats are bathed in high levels of androgen. Female rats have lower levels which are not different from those of male hamsters. Female hamsters are exposed to little androgen. Relevance to behavioral sexual differentiation and the display of adult behavior is discussed.

  18. Reduced mate preference for dominant over subordinate males in old female Syrian hamsters (Mesocricetus auratus).

    PubMed

    Place, Ned J; Vernon, Dianne M; Johnston, Robert E

    2014-10-01

    Why some females choose to mate with a 'preferred' male, whereas others choose to mate with an 'inferior' male is not always clear. Generally, the choosiness of females is thought to decline with advanced age, but relatively few studies have investigated this concept, and reports of this phenomenon in mammals are lacking. To address this deficiency, young and old female golden hamsters were evaluated for their preference for dominant vs. subordinate males. Females observed male dyads as a dominance relationship was established. Dominant and subordinate males were then placed within enclosures at the opposite ends of a Y-maze, and the first approach, scent marking, and time spent near each male were evaluated in young and old females during pro-oestrus-a time when females solicit visits by prospective mates by leaving vaginal and flank scent marks. Whereas the proportion of time spent near the dominant male was significantly greater than random for both young and old females, the proportions of vaginal and flank scent marks left for the dominant male were significantly greater than random for young females, but not for old females. Overall, these results are consistent with a decline in the preference for dominant males by old female hamsters.

  19. Male hamsters discriminate estrous state from vaginal secretions and individuals from flank marks

    PubMed Central

    delBarco-Trillo, Javier; LaVenture, Alex B.; Johnston, Robert E.

    2009-01-01

    It is clear that male hamsters discriminate between the odors of individual, conspecific females, as shown by using habituation-dishabituation methods. However, it is not clear from past research whether male hamsters are able to discriminate between the odors of estrous and non-estrous females. A series of habituation-dishabituation experiments were conducted to determine whether males discriminated between different estrous cycle states using two female secretions, those from flank glands and vaginal secretions. We found that, when habituated to a female flank-gland secretion, males discriminated between this female and a second female on the test trial, whether both were in estrus, both were in diestrus, or one was in estrus and the other in diestrus. There was no difference, however, in the magnitude of their dishabituation response toward flank-gland odors of females in estrus and diestrus. These results suggest that males use flank-gland odors to gain information primarily about individuals. When tested with vaginal secretions in habituation-dishabituation tests, males only showed differences in investigation when the second female was in estrus, indicating that males use vaginal secretions to gain information primarily about reproductive state. PMID:19615611

  20. Dim light at night interferes with the development of the short-day phenotype and impairs cell-mediated immunity in Siberian hamsters (Phodopus sungorus).

    PubMed

    Aubrecht, Taryn G; Weil, Zachary M; Nelson, Randy J

    2014-10-01

    Winter is a challenging time to survive and breed outside of the tropics. Animals use day length (photoperiod) to regulate seasonally appropriate adaptations in anticipation of challenging winter conditions. The net result of these photoperiod-mediated adjustments is enhanced immune function and increased survival. Thus, the ability to discriminate day length information is critical for survival and reproduction in small animals. However, during the past century, urban and suburban development has rapidly expanded and filled the night sky with light from various sources, obscuring crucial light-dark signals, which alters physiological interpretation of day lengths. Furthermore, reduced space, increased proximity to people, and the presence of light at night may act as stressors for small animals. Whereas acute stressors typically enhance immune responses, chronic exposure to stressors often impairs immune responses. Therefore, we hypothesized that the combination of dim light at night and chronic stress interferes with enhanced cell-mediated immunity observed during short days. Siberian hamsters (Phodopus sungorus) were assigned to short or long days with dark nights (0 lux) or dim (5 lux) light at night for 10 weeks. Following 2 weeks of chronic restraint (6 hr/day), a model of chronic stress, delayed type hypersensitivity (DTH) responses were assessed. Both dim light at night and restraint reduced the DTH response. Dim light at night during long nights produced an intermediate short day phenotype. These results suggest the constant presence of light at night could negatively affect survival of photoperiodic rodents by disrupting the timing of breeding and immune responses. © 2014 Wiley Periodicals, Inc.

  1. Revealing the kinetics of Leishmania chagasi infection in the male genital system of hamsters.

    PubMed

    Quintal, Amanda P N; Borges, Bruna C; Brígido, Paula C; Silva, Rebecca T; Notário, Ana F; Santos, Marlus A; de Souza, Maria A; Nascimento, Fernanda G O; Mundim, Antônio V; Costa, Guilherme M J; Vasconcelos, André B; da Silva, Claudio V

    2016-03-29

    Leishmaniasis causes alterations and lesions in the genital system, which leads to azoospermia and testicular atrophy in animals during the chronic phase of the infection. The aim of this study was to reveal the kinetics of Leishmania chagasi infection in the genital system of male golden hamsters (Mesocricetus auratus). Animals were intraperitoneally inoculated with amastigotes from L. chagasi. At different time points animals were euthanized and genital organs processed for histo-pathological, qPCR, cytokines and testosterone detection assays. Our results showed a high parasite load in testis, followed by an increase of pro-inflammatory cytokines IL1-β, TNF-α and IFN-γ, and testosterone. Subsequently, IL-4 expression was upregulated and basal parasite persistence in testis was observed using the experimental approach. Extracellular amastigotes migrated to the epididymis posing as a potential major factor of parasite persistence and venereal transmission of L. chagasi infection in hamsters.

  2. De novo assembly, annotation, and characterization of the whole brain transcriptome of male and female Syrian hamsters

    PubMed Central

    McCann, Katharine E.; Sinkiewicz, David M.; Norvelle, Alisa; Huhman, Kim L.

    2017-01-01

    Hamsters are an ideal animal model for a variety of biomedical research areas such as cancer, virology, circadian rhythms, and behavioural neuroscience. The use of hamsters has declined, however, most likely due to the dearth of genetic tools available for these animals. Our laboratory uses hamsters to study acute social stress, and we are beginning to investigate the genetic mechanisms subserving defeat-induced behavioural change. We have been limited, however, by the lack of genetic resources available for hamsters. In this study, we sequenced the brain transcriptome of male and female Syrian hamsters to generate the necessary resources to continue our research. We completed a de novo assembly and after assembly optimization, there were 113,329 transcripts representing 14,530 unique genes. This study is the first to characterize transcript expression in both female and male hamster brains and offers invaluable information to promote understanding of a host of important biomedical research questions for which hamsters are an excellent model. PMID:28071753

  3. Male Syrian hamsters experimentally infected with Helicobacter spp. of the H. bilis cluster develop MALT-associated gastrointestinal lymphomas

    PubMed Central

    Woods, Stephanie E.; Ek, Courtney; Shen, Zeli; Feng, Yan; Ge, Zhongming; Muthupalani, Sureshkumar; Whary, Mark T.; Fox, James G.

    2015-01-01

    Background Aged hamsters naturally infected with novel Helicobacter spp. classified in the H. bilis cluster develop hepatobiliary lesions and typhlocolitis. Methods To determine if enterohepatic H. spp. contribute to disease, Helicobacter-free hamsters were experimentally infected with H. spp. after suppression of intestinal bacteria by tetracycline treatment of dams and pups. After antibiotic withdrawal, weanlings were gavaged with 4 H. bilis-like Helicobacter spp. isolated from hamsters or H. bilis ATCC 43879 isolated from human feces, and compared to controls (n = 7 per group). Results H. bilis 43879 dosed hamsters were necropsied at 33 WPI due to lack of detectable infection by fecal PCR; at necropsy, 5/7 were weakly PCR positive but lacked intestinal lesions. The remaining hamsters were maintained for ~95 WPI; chronic H. spp. infection in hamsters (6/7) was confirmed by PCR, bacterial culture, FISH and ELISA. Hamsters had mild to moderate typhlitis, and three of the male H. spp. infected hamsters developed small intestinal lymphoma, in contrast to one control. Of the three lymphomas in H. spp. infected hamsters, one was a focal ileal MALT B cell lymphoma, while the other two were multicentric small intestinal large B cell lymphomas involving both the MALT and extra-MALT mucosal sites with lymphoepithelial lesions. The lymphoma in the control hamster was a diffuse small intestinal lymphoma with a mixed population of T and B cells. Conclusions Results suggest persistent H. spp. infection may augment risk for gastrointestinal MALT origin lymphomas. This model is consistent with H. pylori/heilmannii associated MALT lymphoma in humans and could be further utilized to investigate mechanisms of intestinal lymphoma development. PMID:26348390

  4. Predator odour and its impact on male fertility and reproduction in Phodopus campbelli hamsters

    NASA Astrophysics Data System (ADS)

    Vasilieva, N. Y.; Cherepanova, E. V.; von Holst, D.; Apfelbach, R.

    This study investigated the influence of cat urine odour in suppressing development and fertility in Campbell's hamster males. Exposure to this odour from postnatal day 11 until day 45 (sexual maturation) resulted in reduced sex organ weights, reduced testosterone levels and in an increase in abnormalities of the synaptonemal complex in both sex chromosomes and autosomes. Subsequent breeding experiments revealed a significant decrease in litter size. All these data indicate a severe effect of predator odour on the breeding success of potential prey species. It is assumed that these effects are caused by the sulphurous compounds in the urine; however, the underlying mechanisms are not yet known.

  5. The Potential Regressive Role of Syzygium aromaticum on the Reproduction of Male Golden Hamsters

    PubMed Central

    Choi, Donchan; Roh, Hyun Soo; Kang, Dong Won; Lee, Jong Seok

    2014-01-01

    The flower buds of Syzygium aromaticum (clove) have been used as traditional medicine for the treatment of male sexual disorders in Asian countries. Recently, there are some reports about the effects of the clove on reproductive activities in mammals. Therefore, its effect on testicular function was examined in male golden hamsters whose reproductive activity is inhibited by photoperiod such as winter climate. The male animals were given by daily oral administrations (56 consecutive days) in three doses (4 mg, 20 mg, and 100 mg/kg BW) of the alcoholic extract of the clove. Generally lower dose (4 mg) of the extract continued to keep the reproductive activities of testes. The both middle and high doses (20 mg and 100 mg) of the extract completely inhibited the testicular activity in some animals. Taken together, these results suggest a possible biphasic action of alcoholic extract of Syzygium aromaticum flower bud on testicular function. PMID:25949172

  6. Influence of photoinhibition on the morphology and function of pituitary lactotropes in male golden hamsters.

    PubMed

    Cónsole, Gloria M; Jurado, Susana B; Petruccelli, Miguel; Carino, Mónica; Calandra, Ricardo S; Gómez Dumm, César L A

    2002-05-01

    Inhibition of prolactin (PRL) secretion has been previously shown in pituitaries from male and female hamsters exposed to short photoperiods. The purpose of the present study was to analyze the possible quantitative immunohistochemical and ultrastructural changes of PRL cells in male golden hamsters undergoing regression and spontaneous recrudescence, correlating the morphological findings with circulating PRL levels. Thus, adult male golden hamsters were exposed for 8, 16, 22 and 28 weeks to either short photoperiods (SP: 6 h light, 18 h darkness) or long photoperiods (LP: 14 h light, 10 h darkness). Pituitaries were processed for both light and electron microscopy, and serum levels of PRL were assessed by radioimmunoassay (RIA). Volume density (VD = cell area/reference area) and cell density (CD = number of cells/reference area) of lactotropes were measured with an image analysis system (Imaging Technology, Software Optimas 5.2). One hundred lactotropes were recorded for measuring several ultrastructural parameters. When analyzing the lactrotrope cell population from animals submitted to SP, the VD and CD were found to be significantly (p < 0.05) diminished with respect to those of the groups submitted to LP at weeks 8, 16 and 22. However, at week 28 a spontaneous recrudescence appeared. The lactotropes from animals submitted to LP for 8, 16, 22 and 28 weeks exhibited numerous large electrondense secretory granules. The rough endoplasmic reticulum (RER) presented some flat cisternae and numerous free ribosomes. Animals submitted to SP for 8 weeks showed a number of medium and large secretory granules, and the RER exhibited mainly numerous free ribosomes. In those animals submitted to SP for 16 and 22 weeks, lactotropes were found smaller and showed small and medium-sized secretory granules decreased in number. The Golgi complex exhibited some immature granules and dilated cisternae, while the RER did not present differences with respect to the 8-week SP group

  7. Effects of bedding material and running wheel surface on paw wounds in male and female Syrian hamsters.

    PubMed

    Beaulieu, A; Reebs, S G

    2009-01-01

    The present study investigated the effects of bedding material (pine shavings versus beta chip) and running wheel surfaces (standard metal bars versus metal bars covered with a plastic mesh) on the occurrence of wounds on the paws of male and female Syrian (golden) hamsters, Mesocricetus auratus. Four groups of 10 males and 10 females were each assigned to one of the following treatments: pine/no mesh, pine/mesh, chips/no mesh and chips/mesh. Each hamster paw was observed at 1-3-day intervals for 60 days. A total of 1-3 wounds, separate in time, developed on the paws (mostly the hind ones) of almost all animals. Wounds appeared as small pinpricks, cuts or scabs, mostly on the palms. Females ran 15% less than males, yet their front paws were more commonly affected and their wounds tended to last longer. Hamsters with plastic mesh inside their wheels took longer to develop wounds but once they appeared, the wounds were larger and lasted longer. Hamsters on pine shavings developed fewer wounds and had more wound-free days. Hamsters kept running at high levels and many wounds did not heal during the study, suggesting a need for veterinary intervention.

  8. Bitter Melon Seed Extract does not Alter Photoperiodic Effects on Reproduction of Male Golden Hamsters

    PubMed Central

    Choi, Donchan; Lee, Su Ji; Lee, Min Hyuck; Lee, Dong Kyu

    2017-01-01

    ABSTRACT Bitter melon (Momordica charantia, MC) has been used in traditional Korean medicine in treating diabetes. In addition, some reports were emerged, showing the antifertility activities of MC in mammals. We investigated the effects of ethanolic MC extract on the reproductive activity of golden hamsters whose spermatogenetic capacity is controlled by their photoperiods. The animals were divided into 4 groups: long photoperiod (LP) control, short photoperiod (SP) control, and LP animals treated with MC. The animals were orally ingested with low (0.03 g/kg) or high (0.15 g/kg) concentrations of the ethanolic extracts for 8 weeks on the daily basis. The control animals received the vehicle. The animals were then mated with age-matched females, experienced pregnancy. As results, the LP control animals showed active large testes but SP control animals displayed remarkably reduced testes. The animals treated with both concentrations of MC extracts demonstrated large testes, indicating fertile activity as animals in LP. LP control animals had litters as expected, but SP controls had no litters at all. MC extract showed the same results as LP animals in generating offsprings. These results suggest that the MC extract does not change the photoperiodic influence on reproductive activity of male golden hamsters. PMID:28785742

  9. Adrenal, thyroid, and testicular hormone rhythms in male golden hamsters on long and short days

    SciTech Connect

    Ottenweller, J.E.; Tapp, W.N.; Pitman, D.L.; Natelson, B.H. New Jersey Medical School, Newark )

    1987-08-01

    Plasma concentrations of adrenal, thyroid, and testicular hormones were measured at 4-h intervals around the clock in male hamsters on long (14:10-h light-dark cycle) and short (10:14-h light-dark cycle) days. Plasma corticosterone, cortisol, thyroxine (T{sub 4}), triiodothyronine (T{sub 3}), and testosterone rhythms were present on long days. The only one of these hormones to have a significant rhythm on short days was cortisol, but even its amplitude was suppressed compared with the cortisol rhythm on long days. Short days also lowered mean plasma levels of cortisol, T{sub 4}, T{sub 3}, and testosterone. Finally, short days raised the ratio of corticosterone to cortisol and lowered the ratio of T{sub 4} to T{sub 3}. Both ratios had significant rhythms on long days but not on short days. Because of the many interactions among adrenal, thyroid, and testicular hormone axes, it is unclear whether the primary effect of short days is on one of these endocrine systems or on another factor that has separate effects on each of the hormone rhythms that was measured. Nonetheless, it is clear that a major effect of short day lengths in hamsters is to suppress hormone rhythms. Explanations of photoperiodic effects that depend on endocrine mediation should take this into account.

  10. Infrequent low dose testosterone treatment maintains male sexual behavior in Syrian hamsters.

    PubMed

    Piekarski, David J; Routman, David M; Schoomer, Elanor E; Driscoll, Joseph R; Park, Jin Ho; Butler, Matthew P; Zucker, Irving

    2009-01-01

    Testosterone (T) secreted in short pulses several times each day is essential for the maintenance of male sex behavior (MSB) in mammals. Blood T concentrations are relatively low during inter-pulse intervals. Assessment of androgenic influences on MSB of rodents has, with very few exceptions, involved either injections of pure or esterified hormones dissolved in oil or implantation of constant release capsules that generate supraphysiological and/or constantly elevated T concentrations. The minimum daily concentration of T necessary to maintain and restore MSB when T is delivered as a discrete short pulse remains unspecified; nor is it known whether infrequent T pulses in the physiological range sustain MSB. To address these questions, we varied T injection concentrations and frequencies in castrated, sexually-experienced Syrian hamsters. All males injected daily with an aqueous vehicle failed to display the ejaculatory reflex 5 weeks after castration. Once daily 15 microg subcutaneous T injections both maintained and restored MSB, whereas once daily 5 microg T injections resulted in fewer males ejaculating and longer ejaculation latencies. Substantially higher T doses were required to restore MSB in previous studies when T was administered in an oil vehicle. 50 microg T maintained MSB in most hamsters injected once every 4 or 7 days, despite long intervals between injections during which circulating T was undetectable or well below physiological concentrations. Some T regimens that maintained MSB were associated with subnormal seminal vesicle and ventral prostate weights. The demonstration that relatively brief, infrequent elevations of T are sufficient to support MSB provides a useful model to assess the neuroendocrine basis of MSB and raises the possibility that infrequent low dose androgen replacement protocols may restore sex behavior to hypogonadal men without inducing some of the negative side-effects associated with more frequent, higher dose treatments.

  11. The organizational effects of pubertal testosterone on sexual proficiency in adult male Syrian hamsters.

    PubMed

    De Lorme, Kayla C; Sisk, Cheryl L

    2016-10-15

    Social proficiency requires making appropriate behavioral adaptations as a result of social experience. For example, male rodents become sexually proficient with experience as demonstrated by a reduction in ectopic (misdirected) mounts, mount-to-intromission ratio, and latency to ejaculation. We previously found that over a series of timed tests with a receptive female, male hamsters deprived of testosterone specifically during puberty (NoT@P) have overall lower levels of sexual behavior and continue to display high levels of ectopic mounts, compared with males that experienced endogenous testosterone during puberty (T@P). These results suggested that pubertal testosterone programs sexual proficiency in adulthood, but because NoT@P males engaged in less sexual behavior than T@P males in these tests, the amount of sexual experience may have been insufficient to improve sexual proficiency. To more rigorously test the hypothesis that pubertal testosterone is necessary for social proficiency in adulthood, the present study compared the behavior of NoT@P and T@P males in a series of 4 trials with a 48-h interval between each trial. Sexual experience was equated by limiting each trial to 5 intromissions. Sexually-naïve males were either gonadectomized prepubertally (NoT@P) or in adulthood (T@P) and received subcutaneous testosterone capsules four weeks later. Two weeks after testosterone replacement, these groups and a group of adult gonad-intact controls began sexual behavior testing. We found that NoT@P males had more ectopic mounts/min across all four tests compared to gonad-intact and T@P males. Moreover, both gonad-intact and T@P males, but not NoT@P males, showed an increase in the number of mounts and intromissions/min between trials 1 and 3. Unexpectedly, both gonad-intact and T@P, but not NoT@P, males showed a decrease in sexual behaviors during trial 4. Thus, T@P males display multiple behavioral adaptations to sexual experience that are not observed in No

  12. Dorsomedial hypothalamic lesions counteract decreases in locomotor activity in male Syrian hamsters transferred from long to short day lengths.

    PubMed

    Jarjisian, Stephan G; Butler, Matthew P; Paul, Matthew J; Place, Ned J; Prendergast, Brian J; Kriegsfeld, Lance J; Zucker, Irving

    2015-02-01

    The dorsomedial nucleus (DMN) of the hypothalamus has been implicated in seasonal control of reproduction. Syrian hamsters with DMN lesions, unlike control hamsters, do not undergo testicular regression after transfer from a long day length (14 h of light per day; LD) to a short day length (8 h of light per day; SD). SDs also markedly reduce hamster locomotor activity (LMA). To assess whether the DMN is a component of the neural circuitry that mediates seasonal variation in LMA, neurologically intact males (controls) and hamsters that had sustained lesions of the DMN (DMNx) were housed in an LD or SD photoperiod for 26 weeks. DMNx that prevented testicular regression counteracted decreases in LMA during 8 to10 weeks of SD treatment; steroid-independent effects of SDs did not override high levels of LMA in DMNx males. As in previous studies, testosterone (T) restoration increased LMA in LD but not SD castrated control males. In the present study, T also failed to increase LMA in SD-DMNx hamsters. The DMN is not necessary to maintain decreased responsiveness of locomotor activity systems to T in SDs, which presumably is mediated by other central nervous system androgen target tissues. Finally, DMNx did not interfere with the spontaneous increase in LMA exhibited by photorefractory hamsters after 26 weeks of SD treatment. We propose that DMN is an essential part of the substrate that mediates seasonal decreases in LMA as day length decreases but is not required to sustain decreased SD responsiveness to T or for development of refractoriness to SDs. © 2014 The Author(s).

  13. Dorsomedial Hypothalamic Lesions Counteract Decreases in Locomotor Activity in Male Syrian Hamsters Transferred from Long to Short Day Lengths

    PubMed Central

    Paul, Matthew J.; Place, Ned J.; Prendergast, Brian J.; Kriegsfeld, Lance J.; Zucker, Irving

    2015-01-01

    The dorsomedial nucleus (DMN) of the hypothalamus has been implicated in seasonal control of reproduction. Syrian hamsters with DMN lesions, unlike control hamsters, do not undergo testicular regression after transfer from a long day length (14 h of light per day; LD) to a short day length (8 h of light per day; SD). SDs also markedly reduce hamster locomotor activity (LMA). To assess whether the DMN is a component of the neural circuitry that mediates seasonal variation in LMA, neurologically intact males (controls) and hamsters that had sustained lesions of the DMN (DMNx) were housed in an LD or SD photoperiod for 26 weeks. DMNx that prevented testicular regression counteracted decreases in LMA during 8 to10 weeks of SD treatment; steroid-independent effects of SDs did not override high levels of LMA in DMNx males. As in previous studies, testosterone (T) restoration increased LMA in LD but not SD castrated control males. In the present study, T also failed to increase LMA in SD-DMNx hamsters. The DMN is not necessary to maintain decreased responsiveness of locomotor activity systems to T in SDs, which presumably is mediated by other central nervous system androgen target tissues. Finally, DMNx did not interfere with the spontaneous increase in LMA exhibited by photorefractory hamsters after 26 weeks of SD treatment. We propose that DMN is an essential part of the substrate that mediates seasonal decreases in LMA as day length decreases but is not required to sustain decreased SD responsiveness to T or for development of refractoriness to SDs. PMID:25512303

  14. Morphological and biochemical changes of pituitary gonadotropes in male golden hamsters submitted to short and long photoperiods.

    PubMed

    Cónsole, Gloria M; Jurado, Susana B; Camihort, Gisela; Calandra, Ricardo S; Zitta, Karina; Gómez Dumm, César L A

    2002-01-01

    Golden hamsters are seasonal breeders, and a pattern of regression-recrudescence in their hypothalamic-pituitary axis is observed when adult animals are exposed to less than 12.5 h daylight for a prolonged period of time. The purpose of the present work was to investigate the possible morphological and biochemical changes of gonadotrope cell population in male golden hamsters submitted to both short (SP) and long photoperiods (LP). Thus, adult male golden hamsters were exposed to SP (6 h light, 18 h darkness) for 8, 16, 22 and 28 weeks or maintained under LP (14 h light, 10 h darkness). Pituitaries were processed using both light and electron microscopy, and serum levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were assessed by heterologous radioimmunoassay. Volume density [VD = Sigma cell area/reference area (RA)] and cell density (CD = number of cells/RA) of gonadotropes were measured with an image analysis system (Imaging Technology, Software Optimas 5.2). When analyzing the gonadotrope population from animals submitted either to SP or LP, no significant differences were found. At the ultrastructural level, we found a decrease (p < 0.05) in the exocytotic profiles and the individual mean area of secretory granules of both gonadotropes in hamsters maintained under SP for 16 and 22 weeks. Exposure to short days resulted in a decline in serum levels showing a nadir after 16 weeks (p < 0.05). Gonadotropin levels of the hamsters under prolonged exposure to short cycles spontaneously returned to normal values after 22 weeks. In summary, we found a decrease in the ultrastructural and biochemical parameters suggesting an altered release of FSH and LH in male golden hamsters submitted to SP, with a spontaneous recrudescence phase appearing at the end of the study. Copyright 2002 S. Karger AG, Basel

  15. Anabolic androgenic steroids differentially affect social behaviors in adolescent and adult male Syrian hamsters.

    PubMed

    Salas-Ramirez, Kaliris Y; Montalto, Pamela R; Sisk, Cheryl L

    2008-02-01

    Anabolic androgenic steroids (AAS) are synthetic derivatives of testosterone used by over half a million adolescents in the United States for their tissue-building potency and performance-enhancing effects. AAS also affect behavior, including reports of heightened aggression and changes in sexual libido. The expression of sexual and aggressive behaviors is a function of complex interactions among hormones, social context, and the brain, which is extensively remodeled during adolescence. Thus, AAS may have different consequences on behavior during adolescence and adulthood. Using a rodent model, these studies directly compared the effects of AAS on the expression of male sexual and aggressive behaviors in adolescents and adults. Male Syrian hamsters were injected daily for 14 days with either vehicle or an AAS cocktail containing testosterone cypionate (2 mg/kg), nandrolone decanoate (2 mg/kg), and boldenone undecylenate (1 mg/kg), either during adolescence (27-41 days of age) or in adulthood (63-77 days of age). The day after the last injection, males were tested for either sexual behavior with a receptive female or agonistic behavior with a male intruder. Adolescent males treated with AAS showed significant increases in sexual and aggressive behaviors relative to vehicle-treated adolescents. In contrast, AAS-treated adults showed significantly lower levels of sexual behavior compared with vehicle-treated adults and did not show heightened aggression. Thus, adolescents, but not adults, displayed significantly higher behavioral responses to AAS, suggesting that the still-developing adolescent brain is more vulnerable than the adult brain to the adverse consequences of AAS on the nervous system and behavior.

  16. Effects of Social Conflict on POMC-Derived Peptides and Glucocorticoids in Male Golden Hamsters

    DTIC Science & Technology

    1990-01-01

    to laboratory rats, which usually require footshock or labor - treatment had no effect on fighting behavior in hamsters. intensive paradigms such as...control hamster was hormone, vasopressin, or oxytocin . Assay sensitivity was 6 pg/ml. returned to its home cage. Twenty-three (I I experimental wnd 12

  17. Testosterone, androstenedione, and 5alpha-dihydrotestosterone on male sexual behavior and penile spines in the hamster.

    PubMed

    Arteaga-Silva, M; Vigueras-Villaseñor, R M; Retana-Márquez, S; Hernández-González, M; Chihuahua-Serrano, C; Bonilla-Jaime, H; Contreras, J L; Moralí, G

    2008-06-09

    The expression of masculine sexual behavior (MSB) in male hamsters is optimally stimulated by aromatizable androgens like androstenedione (AD) and testosterone (T), while the non-aromatizable androgen, 5alpha-dihydrotestosterone (DHT), exerting potent androgenic peripheral effects, only in high doses maintains MSB after castration. No data exist on the ability of these androgens to restore long intromissions after castration. In this study, AD, T, and DHT were administered to four-week gonadectomized, sexually experienced male hamsters, for three weeks, in doses of 25 microg/day or up to 1000 microg/day to compare their potency in restoring MSB, penile size, and penile spines growth. Plasma levels of these steroids and the metabolites estrone and estradiol, were determined at the end of the treatment period. Gonadectomy completely suppressed MSB and induced a regression of penile spines. AD was more potent than T in restoring MSB, ejaculatory behavior being displayed by most castrated subjects with a lower dose of AD (50 microg/day) than of T (300 microg/day), and long intromissions being shown by all AD-treated castrated hamsters but only by 20% of T-treated ones, when doses of 1000 microg/day were given. DHT did not stimulate any copulatory response. The three androgens, even at the lowest dose, partially stimulated penis and penile epithelium growth, DHT showing the highest potency. Treatment of castrated hamsters with AD (50 microg/day), restored steroid levels to similar values as those of intact animals. These results show that AD and T restored MSB even with a partial stimulation of penile spines growth, AD being more potent than T. In contrast, DHT did not restore MSB in the hamster in spite of its peripheral androgenic potency.

  18. Adolescent anabolic-androgenic steroid exposure alters lateral anterior hypothalamic serotonin-2A receptors in aggressive male hamsters.

    PubMed

    Schwartzer, Jared J; Ricci, Lesley A; Melloni, Richard H

    2009-05-16

    Chronic anabolic-androgenic steroid (AAS) treatment during adolescence facilitates offensive aggression in male Syrian hamsters (Mesocricetus auratus). Serotonin (5-HT) modulates aggressive behavior and has been shown to be altered after chronic treatment with AAS. Furthermore, 5-HT type 2 receptors have been implicated in the control of aggression. For example, treatment with 5-HT(2A) receptor antagonists suppress the generation of the offensive aggressive phenotype. However, it is unclear whether these receptors are sensitive to adolescent AAS exposure. The current study assessed whether treatment with AAS throughout adolescence influenced the immunohistochemical localization of 5-HT(2A) in areas of the hamster brain implicated in the control of aggression. Hamsters were administered AAS (5.0 mg/kg) each day throughout adolescence, scored for offensive aggression, and then examined for differences in 5-HT(2A)-immunoreactivity (5-HT(2A)-ir). When compared with non-aggressive oil-treated controls, aggressive AAS-treated hamsters showed significant increases in 5-HT(2A)-ir fibers in the lateral portion of the anterior hypothalamus (LAH). Further analysis revealed that AAS treatment also produced a significant increase in the number of cells expressing 5-HT(2A)-ir in the LAH. Together, these results support a role for altered 5-HT(2A) expression and further implicate the LAH as a central brain region important in the control of adolescent AAS-induced offensive aggression.

  19. Determination of Hepatotoxicity and Its Underlying Metabolic Basis of 1,2-Dichloropropane in Male Syrian Hamsters and B6C3F1 Mice

    PubMed Central

    Gi, Min; Fujioka, Masaki; Yamano, Shotaro; Shimomura, Eri; Ishii, Naomi; Kakehashi, Anna; Takeshita, Masanori; Wanibuchi, Hideki

    2015-01-01

    1,2-Dichloropropane (1,2-DCP) has recently been reclassified from not classifiable as to its carcinogenicity to humans (Group 3) to carcinogenic to humans (Group 1) by the International Agency for Research on Cancer. This was based on the findings of epidemiological studies in Japan that occupational exposure to paint stripers containing 1,2-DCP was associated with increased cholangiocarcinomas. It is known that 1,2-DCP is negative for cholangiocarcinogenicity in rats and mice. However, its toxicity and carcinogenicity has not been examined in hamsters and little is known about the regulation of its metabolism in hamsters. The purpose of this study was to determine the hepatobiliary toxicity of 1,2-DCP in hamsters and to characterize and compare the altered patterns of hepatic xenometabolic enzymes in hamsters and mice. Male Syrian hamsters and male B6C3F1 mice were treated with various doses of 1,2-DCP for 4 h or 3 days or 4 weeks. These experiments demonstrated that a high dose of 1,2-DCP induced centrilobular hepatocellular necrosis in hamsters. CYP2E1 is possibly the key enzyme responsible for bioactivation and the consequent hepatocytotoxicity of 1,2-DCP, and GSH conjugation catalyzed by GST-T1 may exert a cytoprotective role in hamsters and mice. Notably, the expression pattern of GST-T1 in bile duct epithelial cells differed between hamsters and mice: GST-T1 was expressed in bile duct epithelial cells of mice but not hamsters. This indicates that responses to 1,2-DCP in the bile duct of hamsters might differ from that of mice, and suggests that long-term studies are necessary to clarify the chalangiocarcinogenicity of 1,2-DCP in hamsters, though no biliary toxicity was observed in the present short-term experiments. PMID:25711234

  20. Dissociated functional pathways for appetitive and consummatory reproductive behaviors in male Syrian hamsters.

    PubMed

    Been, Laura E; Petrulis, Aras

    2012-02-01

    In many species, including Syrian hamsters, the generation of male reproductive behavior depends critically on the perception of female odor cues from conspecifics in the environment. The behavioral response to these odors is mediated by a network of steroid-sensitive ventral forebrain nuclei including the medial amygdala (MA), posterior bed nucleus of the stria terminalis (BNST) and medial preoptic area (MPOA). Previous studies have demonstrated that each of these three nuclei is required for appropriate sexual behavior and that MA preferentially sends female odor information directly to BNST and MPOA. It is unknown, however, how the functional connections between MA and BNST and/or MPOA are organized to generate different aspects of reproductive behavior. Therefore, the following experiments used the asymmetrical pathway lesion technique to test the role of the functional connections between MA and BNST and/or MPOA in odor preference and copulatory behaviors. Lesions that functionally disconnected MA from MPOA eliminated copulatory behavior but did not affect odor preference. In contrast, lesions that functionally disconnected MA from BNST eliminated preference for volatile female odors but did not affect preference for directly contacted odors or copulatory behavior. These results therefore demonstrate a double dissociation in the functional connections required for attraction to volatile sexual odors and copulation and, more broadly, suggest that appetitive and consummatory reproductive behaviors are mediated by distinct neural pathways.

  1. Capillary-to-fiber ratio of hind limb muscles in the male Syrian golden hamster.

    PubMed

    Swisher, Anne K; Alway, Stephen E; Yeater, Rachel

    2004-04-01

    The hamster has been the accepted model of emphysema since the 1970s, demonstrating disease-related effects on respiratory skeletal muscle. However, there is scant information available about the model's ability to replicate the peripheral skeletal muscle changes seen in human disease, such as alterations in capillarity. The present study described the capillary-to-fiber ratio (C/F) of normal hamster plantaris, gastrocnemius, and soleus muscles in eight animals. C/F was 1.72 +/- 0.38 for plantaris, 1.95 +/- 0.40 for gastrocnemius, and 2.22 +/- 0.43 for soleus. C/F of soleus was significantly greater (P < 0.01) than plantaris. The C/F of hamster hindlimb muscles varies from those seen in rat species, and having baseline data on hamsters makes it possible to determine the effects of emphysema on C/F in this model.

  2. Melatonin and 6-methoxy-2-benzoxazolinone (6-MBOA) alter the response of the male Syrian hamster to natural photoperiod

    NASA Astrophysics Data System (ADS)

    Vaughan, M. K.; Little, J. C.; Powell, D. C.; Puig-Domingo, M.; Reiter, R. J.

    1988-06-01

    Adult male hamsters bearing either a blank beeswax, 6-methoxy-2-benzoxazolinone (6-MBOA), or melatonin pellet were exposed to 8 weeks (Oct. 6 Dec. 6) of natural autumn decreasing photoperiod (<11 h light) and temperature conditions (mean 10°C for last 4 weeks) or to a 14 h light/10 h dark (14L∶10D) photoperiod and controlled temperature (20°C). Melatonin but not 6-MBOA pellets partially prevented the combined effects of short photoperiod and cold temperatures on the testes and accessory organs. However, both 6-MBOA-and melatonin-treated hamsters maintained outdoors had significantly higher pituitary follicle stimulating hormone (FSH) values compared to their respective indoor-treated controls or to the animals kept outdoors and treated with a blank beeswax pellet. When one compares the various effects of 6-MBOA and melatonin (2 mg/month) on the reproductive system of the male hamster, 6-MBOA is not as effective as melatonin in altering reproductive responses to short photoperiod and cool temperatures at the dose administered.

  3. The posteromedial cortical amygdala regulates copulatory behavior, but not sexual odor preference, in the male Syrian hamster (Mesocricetus auratus).

    PubMed

    Maras, P M; Petrulis, A

    2008-10-15

    In rodent species, the expression of reproductive behavior relies heavily on the perception of social odors, as well as the presence of circulating steroid hormones. In the Syrian hamster, chemosensory and hormonal cues are processed within an interconnected network of ventral forebrain nuclei that regulates many aspects of social behavior. Within this network, the posteromedial cortical amygdala (PMCo) receives direct projections from the accessory olfactory bulbs and contains a dense population of steroid receptor-containing neurons. Consequently, the PMCo may be important for generating odor-guided aspects of reproductive behavior, yet little is known regarding the role of this nucleus in regulating these behaviors. Thus, the present study tested male hamsters with site-specific electrolytic lesions of the PMCo for their (a) sexual odor preference in a Y-maze apparatus, (b) sexual odor discrimination in a habituation-dishabituation task, and (c) copulatory behavior when paired with a sexually receptive female. PMCo-lesioned males preferred to investigate female odors over male odors and were able to discriminate between these odor sources. However, PMCo lesions were associated with several alterations in the male copulatory pattern. First, PMCo-lesioned males displayed increased investigation of the female's non-anogenital region, suggesting that the PMCo may be involved in directing appropriate chemosensory investigation during mating. Second, PMCo lesions altered the temporal pattern of the mating sequence, as PMCo-lesioned males took longer than Sham-lesioned males to reach sexual satiety, as indicated by the delayed expression of long intromissions. This delayed onset of satiety was associated with an increased number of ejaculations compared with Sham-lesioned males. Importantly, these data provide the first direct evidence for a functional role of the PMCo in regulating male reproductive behavior.

  4. Male Syrian Hamsters Experimentally Infected with Helicobacter spp. of the H. bilis Cluster Develop MALT-Associated Gastrointestinal Lymphomas.

    PubMed

    Woods, Stephanie E; Ek, Courtney; Shen, Zeli; Feng, Yan; Ge, Zhongming; Muthupalani, Sureshkumar; Whary, Mark T; Fox, James G

    2016-06-01

    Aged hamsters naturally infected with novel Helicobacter spp. classified in the H. bilis cluster develop hepatobiliary lesions and typhlocolitis. To determine whether enterohepatic H. spp. contribute to disease, Helicobacter-free hamsters were experimentally infected with H. spp. after suppression of intestinal bacteria by tetracycline treatment of dams and pups. After antibiotic withdrawal, weanlings were gavaged with four H. bilis-like Helicobacter spp. isolated from hamsters or H. bilis ATCC 43879 isolated from human feces and compared to controls (n = 7 per group). Helicobacter bilis 43879-dosed hamsters were necropsied at 33 weeks postinfection (WPI) due to the lack of detectable infection by fecal PCR; at necropsy, 5 of 7 were weakly PCR positive but lacked intestinal lesions. The remaining hamsters were maintained for ~95 WPI; chronic H. spp. infection in hamsters (6/7) was confirmed by PCR, bacterial culture, fluorescent in situ hybridization, and ELISA. Hamsters had mild-to-moderate typhlitis, and three of the male H. spp.-infected hamsters developed small intestinal lymphoma, in contrast to one control. Of the three lymphomas in H. spp.-infected hamsters, one was a focal ileal mucosa-associated lymphoid tissue (MALT) B-cell lymphoma, while the other two were multicentric small intestinal large B-cell lymphomas involving both the MALT and extra-MALT mucosal sites with lymphoepithelial lesions. The lymphoma in the control hamster was a diffuse small intestinal lymphoma with a mixed population of T and B cells. Results suggest persistent H. spp. infection may augment risk for gastrointestinal MALT origin lymphomas. This model is consistent with H. pylori/heilmannii-associated MALT lymphoma in humans and could be further utilized to investigate the mechanisms of intestinal lymphoma development. © 2015 John Wiley & Sons Ltd.

  5. Unrefined and refined black raspberry seed oils significantly lower triglycerides and moderately affect cholesterol metabolism in male Syrian hamsters.

    PubMed

    Ash, Mark M; Wolford, Kate A; Carden, Trevor J; Hwang, Keum Taek; Carr, Timothy P

    2011-09-01

    Unrefined and refined black raspberry seed oils (RSOs) were examined for their lipid-modulating effects in male Syrian hamsters fed high-cholesterol (0.12% g/g), high-fat (9% g/g) diets. Hamsters fed the refined and the unrefined RSO diets had equivalently lower plasma total cholesterol and high-density lipoprotein (HDL) cholesterol in comparison with the atherogenic coconut oil diet. The unrefined RSO treatment group did not differ in liver total and esterified cholesterol from the coconut oil-fed control animals, but the refined RSO resulted in significantly elevated liver total and esterified cholesterol concentrations. The unrefined RSO diets significantly lowered plasma triglycerides (46%; P=.0126) in comparison with the coconut oil diet, whereas the refined RSO only tended to lower plasma triglyceride (29%; P=.1630). Liver triglyceride concentrations were lower in the unrefined (46%; P=.0002) and refined (36%; P=.0005) RSO-fed animals than the coconut oil group, with the unrefined RSO diet eliciting a lower concentration than the soybean oil diet. Both RSOs demonstrated a null or moderate effect on cholesterol metabolism despite enrichment in linoleic acid, significantly lowering HDL cholesterol but not non-HDL cholesterol. Dramatically, both RSOs significantly reduced hypertriglyceridemia, most likely due to enrichment in α-linolenic acid. As a terrestrial source of α-linolenic acid, black RSOs, both refined and unrefined, provide a promising alternative to fish oil supplementation in management of hypertriglyceridemia, as demonstrated in hamsters fed high levels of dietary triglyceride and cholesterol.

  6. A 15-minute light pulse during darkness prevents the antigonadotrophic action of afternoon melatonin injections in male hamsters

    NASA Astrophysics Data System (ADS)

    Reiter, R. J.; Hurlbut, E. C.; King, T. S.; Richardson, B. A.; Vaughan, M. K.; Kosub, K. Y.

    1982-12-01

    When adult male Syrian hamsters were maintained under 14 h light and 10 h darkness daily (lights on from 0600-2000 h), peak pineal melatonin levels (705 pg/gland) were attained at 0500 h. When the dark phase of the light:dark cycle was interrupted with a 15 min pulse of light from 2300 2315 h (3 h after lights out), the highest melatonin levels achieved was roughly 400 pg/gland. Finally, if the 15 min pulse of light was given at 0200 0215 h (6 h after lights out) the nocturnal rise in pineal melatonin was completely abolished. Having made these observations, a second experiment was designed to determine the ability of afternoon melatonin injections to inhibit reproduction in hamsters kept under an uninterrupted 14∶10 cycle or under the same lighting regimen where the dark phase was interrupted with a 15 min pulse of light (0200 0215 h). In the uninterrupted light:dark schedule the daily afternoon injection of 25 μg melatonin caused the testes and the accessory sex organs to atrophy within 11 weeks. Conversely, if the dark phase was interrupted with light between 0200 0215 h, afternoon melatonin injections were incapable of inhibiting the growth of the reproductive organs. The findings suggest that exogenously administered melatonin normally synergizes with endogenously produced melatonin to cause gonadal involution in hamsters.

  7. The influence of natural short photoperiodic and temperature conditions on plasma thyroid hormones and cholesterol in male Syrian hamsters

    NASA Astrophysics Data System (ADS)

    Vaughan, M. K.; Brainard, G. C.; Reiter, R. J.

    1984-09-01

    Adult male Syrian hamsters were subjected to 1, 3, 5, 7 or 11 weeks of either natural winter conditions or rigorously controlled laboratory conditions (LD 10∶14; 22 ± 2‡C). Although both groups of hamsters gained weight over the course of the experiment, hamsters housed indoors were significantly heavier after 5 weeks of treatment compared to their outdoors counterparts. Animals housed under natural conditions exhibited a significant decrease in circulating levels of thyroxine (T4) and a rapid rise in triiodothyronine (T3) levels; the free T4 and free T3 index (FT4I and FT3I) mirrored the changes in circulating levels of the respective hormones. Laboratory-housed animals had a slight rise in T4 and FT4I at 3 weeks followed by a slow steady decline in these values; T3 and FT3I values did not change remarkably in these animals. Plasma cholesterol declined steadily over the course of the experiment in laboratory-maintained animals but increased slightly during the first 5 weeks in animals under natural conditions. Since the photoperiodic conditions were approximately of the same duration in these 2 groups, it is concluded that the major differences in body weight, thyroid hormone values and plasma cholesterol are due to some component (possibly temperature) in the natural environment.

  8. An Endocannabinoid Signaling System Modulates Anxiety-like Behavior in Male Syrian Hamsters

    PubMed Central

    Moise, Anna M.; Eisenstein, Sarah A.; Astarita, Giuseppe; Piomelli, Daniele; Hohmann, Andrea G.

    2009-01-01

    Rationale An endocannabinoid signaling system has not been identified in hamsters. Objective We examined the existence of an endocannabinioid signaling system in Syrian hamsters using neuroanatomical, biochemical and behavioral pharmacological approaches. Method The distribution of cannabinoid receptors was mapped and membrane fatty-acid amide hydrolase (FAAH) activity and levels of fatty-acid amides were measured in hamster brain. The impact of cannabinoid CB1 receptor blockade and inhibition of FAAH was evaluated in the elevated plus maze, rota-rod test and models of unconditioned and conditioned social defeat. Results A characteristic heterogeneous distribution of cannabinoid receptors was detected in hamster brain using [3H]CP55,940 binding and autoradiography. The FAAH inhibitor URB597 inhibited FAAH activity (IC50 = 12.8 nM) and elevated levels of fatty-acid amides (N-palmitoyl ethanolamine (PEA) and N-oleoyl ethanolamine (OEA)) in hamster brain. Anandamide levels were not reliably altered. The cannabinoid agonist WIN55,212-2 (1– 10 mg/kg i.p.) induced CB1-mediated motor ataxia. Blockade of CB1 with rimonabant (5 mg/kg i.p.) induced anxiogenic-like behavior in the elevated plus maze. URB597 (0.1–0.3 mg/kg i.p.) induced CB1-mediated anxiolytic-like effects in elevated plus maze, similar to the benzodiazepine diazepam (2 mg/kg i.p.). Diazepam (2–6 mg/kg i.p.) suppressed the expression, but not the acquisition, of conditioned defeat. By contrast, neither URB597 (0.3–3.0 mg/kg i.p.) nor rimonabant (5 mg/kg i.p.) altered unconditioned or conditioned social defeat or rota-rod performance. Conclusions Endocannabinoids engage functional CB1 receptors in hamster brain to suppress anxiety-like behavior and undergo enzymatic hydrolysis catalyzed by FAAH. Our results further suggest that neither unconditioned nor conditioned social defeat in the Syrian hamster is dependent upon cannabinoid CB1 receptor activation. PMID:18545985

  9. An endocannabinoid signaling system modulates anxiety-like behavior in male Syrian hamsters.

    PubMed

    Moise, Anna M; Eisenstein, Sarah A; Astarita, Giuseppe; Piomelli, Daniele; Hohmann, Andrea G

    2008-10-01

    An endocannabinoid signaling system has not been identified in hamsters. We examined the existence of an endocannabinoid signaling system in Syrian hamsters using neuroanatomical, biochemical, and behavioral pharmacological approaches. The distribution of cannabinoid receptors was mapped, and membrane fatty-acid amide hydrolase (FAAH) activity and levels of fatty-acid amides were measured in hamster brain. The impact of cannabinoid CB1 receptor blockade and inhibition of FAAH was evaluated in the elevated plus maze, rota-rod test, and models of unconditioned and conditioned social defeat. A characteristic heterogeneous distribution of cannabinoid receptors was detected in hamster brain using [3H]CP55,940 binding and autoradiography. The FAAH inhibitor URB597 inhibited FAAH activity (IC50 = 12.8 nM) and elevated levels of fatty-acid amides (N-palmitoyl ethanolamine and N-oleoyl ethanolamine) in hamster brain. Anandamide levels were not reliably altered. The cannabinoid agonist WIN55,212-2 (1- 10 mg/kg i.p.) induced CB1-mediated motor ataxia. Blockade of CB1 with rimonabant (5 mg/kg i.p.) induced anxiogenic-like behavior in the elevated plus maze. URB597 (0.1-0.3 mg/kg i.p.) induced CB1-mediated anxiolytic-like effects in the elevated plus maze, similar to the benzodiazepine diazepam (2 mg/kg i.p.). Diazepam (2-6 mg/kg i.p.) suppressed the expression, but not the acquisition, of conditioned defeat. By contrast, neither URB597 (0.3-3.0 mg/kg i.p.) nor rimonabant (5 mg/kg i.p.) altered unconditioned or conditioned social defeat or rota-rod performance. Endocannabinoids engage functional CB1 receptors in hamster brain to suppress anxiety-like behavior and undergo enzymatic hydrolysis catalyzed by FAAH. Our results further suggest that neither unconditioned nor conditioned social defeat in the Syrian hamster is dependent upon cannabinoid CB1 receptor activation.

  10. A 1-bp deletion in Fgf5 causes male-dominant long hair in the Syrian hamster.

    PubMed

    Yoshizawa, Yasuhiro; Wada, Kenta; Shimoi, Gaku; Shiomi, Gaku; Kameyama, Yuichi; Wakabayashi, Yuichi; Fukuta, Katsuhiro; Hashizume, Ryoichi

    2015-12-01

    Hair length in mammals is generally regulated by the hair cycle, and its disruption leads to abnormal hair morphogenesis in several species. FGF5, one of the hair cycle regulators, has a role in inducing catagen, and that mutation causes abnormal hair length in both sexes in humans, mice, dogs, and cats. Male-dominant long-haired coat (MALC) is an inbred strain of Syrian hamster exhibiting spontaneous long hair in males. After castration, MALC exhibited significantly shorter hair than the control individuals, but testosterone administration to castrated MALC showed reversion to the original phenotype. Moreover, flutamide administration led to MALC phenotype repression. Histological analysis revealed that hair follicle regression was shown in the wild-type 4 weeks after depilation, but that of MALC remained in the anagen phase. We detected a c.546delG of Fgf5 in MALC (Fgf5malc) that might lead to truncation resulting from a frame shift in FGF5 (p.Arg184GlyfsX6). Additionally, homozygous Fgf5malc was only detected in long-haired (Slc:Syrian×MALC)F2 and (J-2-Nn×MALC)F2 progenies, and all homozygous wild and heterozygous Fgf5malc individuals showed normal hair length. Thus, Fgf5malc leads to male-dominant long hair via a prolonged anagen phase which is affected by testosterone in hamsters. To our knowledge, this report is the first to present the sexual dimorphism of hair length caused by the Fgf5 mutation.

  11. The protein synthesis inhibitor anisomycin reduces sex behavior during a critical period after testosterone treatment in male Syrian hamsters.

    PubMed

    Piekarski, David J; Seto, Tiffany; Zucker, Irving

    2012-01-18

    Testosterone (T) is critical for maintaining male sexual behavior (MSB) in rodents, in part by altering protein synthesis in a well-defined neural circuit. The specific timing of protein synthesis essential for expression of MSB has never been investigated. We administered the protein synthesis inhibitor anisomycin (Ani) to castrated male Syrian hamsters treated sc with 100 μg T in an aqueous vehicle once weekly; this T regimen maintains MSB while elevating circulating T concentrations for only a few hours after each injection. Hamsters were injected s.c. with the vehicle or 12.5 mg Ani at one of several times relative to T administration; MSB was assessed once per week, 6 days after the previous T injection, for 5 weeks. Anisomycin administered 6-12 h after T injection significantly reduced the expression of sexual behavior, whereas Ani treatment between 3 h before and 3 h after T injection did not impair MSB. This experiment is the first to assess the specific timing of protein synthesis relative to a T pulse that is required for the expression of MSB. The demarcation of a critical interval for T-induced protein synthesis necessary for maintenance of MSB should facilitate specification of the genomic, proteomic, and biochemical cascades that subserve actions of T on male copulation.

  12. Siberian Islands

    Atmospheric Science Data Center

    2013-04-16

    ... Distinguishing Clouds from Ice over the East Siberian Sea, Russia     View Larger Image ... from different angles. Owing to their elevation above sea level, clouds are mapped as green and yellow areas, whereas land, sea ice, and ...

  13. Nocturnal illumination maintains reproductive function and simulates the period-lengthening effect of constant light in the mature male Djungarian hamster (Phodopus sungorus)

    NASA Technical Reports Server (NTRS)

    Ferraro, J. S.

    1990-01-01

    Mature male Djungarian hamsters (Phodopus sungorus) were placed in individual light-tight, sound attenuated chambers and exposed to one of four lighting conditions for a duration of approximately seven weeks. The four lighting conditions were: constant light (LL); constant dark (DD); feedback lighting (LDFB; a condition that illuminates the cage in response to locomotor activity); or a feedback lighting neighbor control (LDFB NC; the animal receives the same light pattern as a paired animal in feedback lighting, but has no control over it). Exposure of hamsters to LL or LDFB produced significantly and similarly longer free-running periods of the locomotor activity rhythm than exposure of animals to DD. Hamsters exposed to LDFB NC did not free-run or entrain, but rather displayed "relative coordination". The paired testes and sex accessory glands weights suggest that in the Djungarian hamster, LL and LDFB exposed animals maintained reproductive function, whereas DD exposed animals did not. Animals exposed to LDFB NC had intermediate paired testes weights. Since several previous studies have demonstrated that short pulses of light, which are coincident with the subjective night, are photostimulatory, it is not surprising that LDFB maintained reproductive function in the mature Djungarian hamster. Feedback lighting, however, has been shown to be an insufficient stimulus to maintain reproductive function of mature male and female Syrian hamsters, and to the reproductive maturation of immature Djungarian hamsters. The results suggest that there may be slight, but significant differences in the way these two species interpret photoperiod, as well as a developmental change in the photoperiodic response of Djungarian hamsters.

  14. Nocturnal illumination maintains reproductive function and simulates the period-lengthening effect of constant light in the mature male Djungarian hamster (Phodopus sungorus)

    NASA Technical Reports Server (NTRS)

    Ferraro, J. S.

    1990-01-01

    Mature male Djungarian hamsters (Phodopus sungorus) were placed in individual light-tight, sound attenuated chambers and exposed to one of four lighting conditions for a duration of approximately seven weeks. The four lighting conditions were: constant light (LL); constant dark (DD); feedback lighting (LDFB; a condition that illuminates the cage in response to locomotor activity); or a feedback lighting neighbor control (LDFB NC; the animal receives the same light pattern as a paired animal in feedback lighting, but has no control over it). Exposure of hamsters to LL or LDFB produced significantly and similarly longer free-running periods of the locomotor activity rhythm than exposure of animals to DD. Hamsters exposed to LDFB NC did not free-run or entrain, but rather displayed "relative coordination". The paired testes and sex accessory glands weights suggest that in the Djungarian hamster, LL and LDFB exposed animals maintained reproductive function, whereas DD exposed animals did not. Animals exposed to LDFB NC had intermediate paired testes weights. Since several previous studies have demonstrated that short pulses of light, which are coincident with the subjective night, are photostimulatory, it is not surprising that LDFB maintained reproductive function in the mature Djungarian hamster. Feedback lighting, however, has been shown to be an insufficient stimulus to maintain reproductive function of mature male and female Syrian hamsters, and to the reproductive maturation of immature Djungarian hamsters. The results suggest that there may be slight, but significant differences in the way these two species interpret photoperiod, as well as a developmental change in the photoperiodic response of Djungarian hamsters.

  15. Determination of Hepatotoxicity and Its Underlying Metabolic Basis of 1,2-Dichloropropane in Male Syrian Hamsters and B6C3F1 Mice.

    PubMed

    Gi, Min; Fujioka, Masaki; Yamano, Shotaro; Shimomura, Eri; Ishii, Naomi; Kakehashi, Anna; Takeshita, Masanori; Wanibuchi, Hideki

    2015-05-01

    1,2-Dichloropropane (1,2-DCP) has recently been reclassified from not classifiable as to its carcinogenicity to humans (Group 3) to carcinogenic to humans (Group 1) by the International Agency for Research on Cancer. This was based on the findings of epidemiological studies in Japan that occupational exposure to paint stripers containing 1,2-DCP was associated with increased cholangiocarcinomas. It is known that 1,2-DCP is negative for cholangiocarcinogenicity in rats and mice. However, its toxicity and carcinogenicity has not been examined in hamsters and little is known about the regulation of its metabolism in hamsters. The purpose of this study was to determine the hepatobiliary toxicity of 1,2-DCP in hamsters and to characterize and compare the altered patterns of hepatic xenometabolic enzymes in hamsters and mice. Male Syrian hamsters and male B6C3F1 mice were treated with various doses of 1,2-DCP for 4 h or 3 days or 4 weeks. These experiments demonstrated that a high dose of 1,2-DCP induced centrilobular hepatocellular necrosis in hamsters. CYP2E1 is possibly the key enzyme responsible for bioactivation and the consequent hepatocytotoxicity of 1,2-DCP, and GSH conjugation catalyzed by GST-T1 may exert a cytoprotective role in hamsters and mice. Notably, the expression pattern of GST-T1 in bile duct epithelial cells differed between hamsters and mice: GST-T1 was expressed in bile duct epithelial cells of mice but not hamsters. This indicates that responses to 1,2-DCP in the bile duct of hamsters might differ from that of mice, and suggests that long-term studies are necessary to clarify the chalangiocarcinogenicity of 1,2-DCP in hamsters, though no biliary toxicity was observed in the present short-term experiments. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  16. Photoperiodic regulation of compensatory testicular hypertrophy in hamsters.

    PubMed

    Paul, Matthew J; Park, Jin Ho; Horton, Teresa H; Alvarez, Maria I; Burke, Morgan K; Place, Ned J; Zucker, Irving

    2006-08-01

    In mammals, removal of one testis results in compensatory testicular hypertrophy (CTH) of the remaining gonad. Although CTH is ubiquitous among juveniles of many species, laboratory rats, laboratory mice, and humans unilaterally castrated in adulthood fail to display CTH. We documented CTH in pre- and postpubertally hemi-castrated Syrian and Siberian hamsters and tested whether day length affects CTH in juvenile and adult Siberian hamsters. Robust CTH was evident in long-day hemi-castrates of both species and was preceded by increased serum FSH concentrations in juvenile Siberian hamsters. In sharp contrast, CTH was undetectable in short-day hemi-castrated Siberian hamsters for several months and only made its appearance with the development of neuroendocrine refractoriness to short day lengths; serum FSH concentrations of juveniles also did not increase above sham-castrate values until the onset of refractoriness. Long-day hemi-castrated Siberian hamsters with hypertrophied testes underwent complete gonadal regression after transfer to short days, albeit at a reduced rate for the first 3 weeks of treatment. Blood testosterone concentrations of adult hamsters did not differ between long-day hemicastrates and sham-castrates 9-12 weeks after surgery. We conclude that CTH is suppressed by short day lengths in Siberian hamsters at all ages and stages of reproductive development; in short day lengths, but not long day lengths, the remaining testis produces sufficient negative feedback inhibition to restrain FSH hypersecretion and prevent CTH.

  17. [Induction of androgenic cultures in Siberian larch].

    PubMed

    Ivanova, A N; Tret'iakova, I N; Viazovetskova, A S

    2006-01-01

    Male generative buds of the Siberian larch have no organic quiescence during the autumn-winter period and are capable of completing the development of male generative structures under favorable conditions. When microsporophylls of the Siberian larch were cultivated on medium MS with 0.2 mg/l 2,4-D, embryoids of two types were obtained: directly from the microspore body and via formation of organogenic callus. This means that in the Siberian larch, direct and indirect androgenesis in vitro is possible. The Siberian larch pollen was first germinated in vitro, which was enhanced by pretreatment with hydrogen peroxide.

  18. Mate preference for dominant vs. subordinate males in young female Syrian hamsters (Mesocricetus auratus) following chemically-accelerated ovarian follicle depletion.

    PubMed

    Roosa, Kristen A; Place, Ned J

    2015-12-01

    Life history theory predicts that selectivity for mates generally declines as females age. We previously demonstrated this phenomenon in Syrian hamsters (Mesocricetus auratus), in that older females showed reduced preference for dominant over subordinate males. To test the hypothesis that decreased reproductive quality due to aging reduces mate preference, we decoupled reproductive and chronological age by treating young female hamsters with 4-vinylcyclohexene diepoxide (VCD), which destroys ovarian follicles and functionally accelerates ovarian follicle depletion without compromising the general health of rodents. In this study, VCD effectively reduced follicle numbers in young Syrian hamsters. VCD-treated and control females were allowed to choose between a dominant and a subordinate male in a Y-maze on the day of proestrus. Both VCD-treated and control females demonstrated preference for the dominant male by leaving a greater proportion of vaginal scent marks near him, which is a behavior that females display when soliciting prospective mates. However, there was no effect of treatment on the proportion of vaginal scent marks left for the dominant male. Furthermore, ovarian follicle numbers were not significantly correlated with any behaviors in either group. We conclude that accelerated ovarian follicle depletion does not reduce mate preference in young female hamsters.

  19. Winter day lengths counteract stimulatory effects of apomorphine and yohimbine on sexual behavior of male Syrian hamsters.

    PubMed

    Piekarski, David J; Jarjisian, Stephan G; Zucker, Irving

    2012-08-01

    Yohimbine and apomorphine selectively act on noradrenergic and dopaminergic neural substrates to augment male sexual behavior (MSB) in several rodent species. The present study assessed whether these drugs can overcome the suppressive effects of short winter-like day lengths on MSB. Yohimbine treatments that markedly increase copulatory behavior of male hamsters in long days were completely ineffective in facilitating MSB when injected after gonadal regression induced by 16 wks of short day lengths and after complete gonadal recrudescence after 32 wks of short days; apomorphine was similarly ineffective. The brain circuit that mediates MSB either may be less responsive to yohimbine and apomorphine in short than long days, or these drugs may not produce equivalent neurotransmitter changes in the two day lengths. After 32 wks of short-day treatment, all males had undergone testicular recrudescence and successfully ejaculated on initial tests with sexually receptive females after a hiatus of at least 4 mo during which they were denied mating opportunities. This suggests that overwintering males in the field are in a state of reproductive readiness at the outset of spring conditions favorable for survival of offspring.

  20. The effects of feedback lighting on the circadian rhythm of locomotor activity and the reproductive maturation of the male Djungarian hamster (Phodopus sungorus)

    NASA Technical Reports Server (NTRS)

    Ferraro, J. S.

    1988-01-01

    The non-parametric model of entrainment suggests that brief pulses of light, delivered between dusk and dawn can simulate the phasing effects of full photoperiods or even constant light (LL). Feedback lighting (LDFB) is a lighting condition where individual animals, otherwise in constant darkness (DD), are exposed to light in response to a monitored behavior. The specific purpose of this type of illumination is to expose the circadian cycle to light only during the subjective night. LDFB has been used to support this hypothesis in several species of nocturnal rodents and one species of diurnal primate by producing similar free-running periods in LDFB as in LL. This lighting condition has also been used to test the hypothesis that exposing the subjective night to even short duration light pulses will maintain reproductive function in long day breeders. In the Syrian hamster (Mesocricetus auratus), however, LDFB is not as photostimulatory as LL despite extensive light exposure during the subjective night. In the experiments presented here, a group of immature male Djungarian hamsters (Phodopus sungorus) were placed in individual light-tight sound attenuated chambers where they had free access to food, water and an activity wheel. The animals were exposed to one of four lighting conditions [DD, LL, LDFB or a neighbor control of feedback lighting (LDFB NC)] for approximately 30 days shortly after weaning. LDFB NC is a lighting condition where a neighbor control hamster receives the identical lighting regime as a paired animal exposing itself to LDFB, yet the neighbor has no control over it. A fifth group was exposed to a light-dark cycle of 16 hours of light and 8 hours of dark (LD16:8). This group was housed in cages in a colony room and did not have access to a running wheel. The free-running periods of the locomotor activity rhythms for hamsters exposed to LDFB and LL were not similar, unlike the results for rats, Syrian hamsters, mice, monkeys and even mature

  1. The effects of feedback lighting on the circadian rhythm of locomotor activity and the reproductive maturation of the male Djungarian hamster (Phodopus sungorus)

    NASA Technical Reports Server (NTRS)

    Ferraro, J. S.

    1988-01-01

    The non-parametric model of entrainment suggests that brief pulses of light, delivered between dusk and dawn can simulate the phasing effects of full photoperiods or even constant light (LL). Feedback lighting (LDFB) is a lighting condition where individual animals, otherwise in constant darkness (DD), are exposed to light in response to a monitored behavior. The specific purpose of this type of illumination is to expose the circadian cycle to light only during the subjective night. LDFB has been used to support this hypothesis in several species of nocturnal rodents and one species of diurnal primate by producing similar free-running periods in LDFB as in LL. This lighting condition has also been used to test the hypothesis that exposing the subjective night to even short duration light pulses will maintain reproductive function in long day breeders. In the Syrian hamster (Mesocricetus auratus), however, LDFB is not as photostimulatory as LL despite extensive light exposure during the subjective night. In the experiments presented here, a group of immature male Djungarian hamsters (Phodopus sungorus) were placed in individual light-tight sound attenuated chambers where they had free access to food, water and an activity wheel. The animals were exposed to one of four lighting conditions [DD, LL, LDFB or a neighbor control of feedback lighting (LDFB NC)] for approximately 30 days shortly after weaning. LDFB NC is a lighting condition where a neighbor control hamster receives the identical lighting regime as a paired animal exposing itself to LDFB, yet the neighbor has no control over it. A fifth group was exposed to a light-dark cycle of 16 hours of light and 8 hours of dark (LD16:8). This group was housed in cages in a colony room and did not have access to a running wheel. The free-running periods of the locomotor activity rhythms for hamsters exposed to LDFB and LL were not similar, unlike the results for rats, Syrian hamsters, mice, monkeys and even mature

  2. The effects of feedback lighting on the circadian rhythm of locomotor activity and the reproductive maturation of the male Djungarian hamster (Phodopus sungorus).

    PubMed

    Ferraro, J S

    1988-01-01

    The non-parametric model of entrainment suggests that brief pulses of light, delivered between dusk and dawn can simulate the phasing effects of full photoperiods or even constant light (LL). Feedback lighting (LDFB) is a lighting condition where individual animals, otherwise in constant darkness (DD), are exposed to light in response to a monitored behavior. The specific purpose of this type of illumination is to expose the circadian cycle to light only during the subjective night. LDFB has been used to support this hypothesis in several species of nocturnal rodents and one species of diurnal primate by producing similar free-running periods in LDFB as in LL. This lighting condition has also been used to test the hypothesis that exposing the subjective night to even short duration light pulses will maintain reproductive function in long day breeders. In the Syrian hamster (Mesocricetus auratus), however, LDFB is not as photostimulatory as LL despite extensive light exposure during the subjective night. In the experiments presented here, a group of immature male Djungarian hamsters (Phodopus sungorus) were placed in individual light-tight sound attenuated chambers where they had free access to food, water and an activity wheel. The animals were exposed to one of four lighting conditions [DD, LL, LDFB or a neighbor control of feedback lighting (LDFB NC)] for approximately 30 days shortly after weaning. LDFB NC is a lighting condition where a neighbor control hamster receives the identical lighting regime as a paired animal exposing itself to LDFB, yet the neighbor has no control over it. A fifth group was exposed to a light-dark cycle of 16 hours of light and 8 hours of dark (LD16:8). This group was housed in cages in a colony room and did not have access to a running wheel. The free-running periods of the locomotor activity rhythms for hamsters exposed to LDFB and LL were not similar, unlike the results for rats, Syrian hamsters, mice, monkeys and even mature

  3. Steroidal control of male hamster sexual behavior in Me and MPOA: effects of androgen dose and tamoxifen.

    PubMed

    Wood, R I; Williams, S J

    2001-04-01

    Steroids stimulate male sexual behavior through interconnected limbic nuclei, including the medial amygdala (Me) and medial preoptic area (MPOA). Although Me and MPOA each can transduce hormonal cues to induce sexual activity in castrated male hamsters, simultaneous stimulation of Me and MPOA fails to amplify mating. The present study extends our investigations of redundancy in the hormonal control of mating by testing the behavioral effects of (1) increasing steroid dose in a single brain region or (2) locally blocking steroid action with an estrogen antagonist. In Experiment 1, sexually experienced castrates received a single testosterone implant in Me, bilateral testosterone implants, or a single implant of a highly potent androgen, 7a-methyl-19-nortestosterone (MENT). These treatments stimulated mating behavior: 2 weeks after surgery, mounting was observed in > or =50% of the males in each group. In Experiment 2, castrated males received intracerebral implants of the estrogen antagonist tamoxifen in Me or MPOA, combined with systemic testosterone replacement. Tamoxifen in MPOA had minimal effects on the recovery of mating behavior. With tamoxifen in Me, mounts and intromissions were significantly reduced 18 days after surgery. However, the percent of males in each group that expressed mounts, intromissions or ejaculations was not different. Thus, in Experiment 1, increasing the amount of steroid does not amplify mating. Likewise, local blockade of hormone action in Experiment 2 does not prevent behavior. These findings support the concept that steroids are largely permissive for male sex behavior. Steroid stimulation of either Me or MPOA is sufficient for sexual activity. Conversely, neither Me nor MPOA has an absolute requirement for hormones to facilitate expression of mating.

  4. Castration reduces male testosterone, estradiol, and territorial aggression, but not paternal behavior in biparental dwarf hamsters (Phodopus campbelli).

    PubMed

    Hume, Johanna M; Wynne-Edwards, Katherine E

    2005-09-01

    Biparental male hamsters, Phodopus campbelli, act as midwives during the birth of their litter and are highly responsive to an experimentally displaced pup. They also have high peripheral concentrations of estradiol, a hormone with known roles in maternal behavior. Surgical castration during the gestation of their first litter was used to investigate the source of that estradiol and the functional role of testicular sex steroids in paternal responsiveness. In Experiment I, castration reduced both testosterone and estradiol concentrations, confirming that the testes were the primary source of estradiol. However, neither paternal responsiveness nor multiple measures of reproductive success were altered by the castration. Aggression directed towards an intruder, however, was reduced by castration. In Experiment II, removal of prior experience with birth or pups also failed to alter paternal responsiveness in castrated males. Although the present results do not preclude a role for local estradiol synthesis in the brain, results do not support an association between high circulating estradiol in males and their paternal behavior.

  5. Valganciclovir Inhibits Human Adenovirus Replication and Pathology in Permissive Immunosuppressed Female and Male Syrian Hamsters

    PubMed Central

    Toth, Karoly; Ying, Baoling; Tollefson, Ann E.; Spencer, Jacqueline F.; Balakrishnan, Lata; Sagartz, John E.; Buller, Robert Mark L.; Wold, William S. M.

    2015-01-01

    Adenovirus infections of immunocompromised pediatric hematopoietic stem cell transplant patients can develop into serious and often deadly multi-organ disease. There are no drugs approved for adenovirus infections. Cidofovir (an analog of 2-deoxycytidine monophosphate) is used at times but it can be nephrotoxic and its efficacy has not been proven in clinical trials. Brincidofovir, a promising lipid-linked derivative of cidofovir, is in clinical trials. Ganciclovir, an analog of 2-deoxyguanosine, has been employed occasionally but with unknown efficacy in the clinic. In this study, we evaluated valganciclovir against disseminated adenovirus type 5 (Ad5) infection in our permissive immunosuppressed Syrian hamster model. We administered valganciclovir prophylactically, beginning 12 h pre-infection or therapeutically starting at Day 1, 2, 3, or 4 post-infection. Valganciclovir significantly increased survival, reduced viral replication in the liver, and mitigated the pathology associated with Ad5 infection. In cultured cells, valganciclovir inhibited Ad5 DNA replication and blocked the transition from early to late stage of infection. Valganciclovir directly inhibited Ad5 DNA polymerase in vitro, which may explain, at least in part, its mechanism of action. Ganciclovir and valganciclovir are approved to treat infections by certain herpesviruses. Our results support the use of valganciclovir to treat disseminated adenovirus infections in immunosuppressed patients. PMID:25807051

  6. Valganciclovir inhibits human adenovirus replication and pathology in permissive immunosuppressed female and male Syrian hamsters.

    PubMed

    Toth, Karoly; Ying, Baoling; Tollefson, Ann E; Spencer, Jacqueline F; Balakrishnan, Lata; Sagartz, John E; Buller, Robert Mark L; Wold, William S M

    2015-03-23

    Adenovirus infections of immunocompromised pediatric hematopoietic stem cell transplant patients can develop into serious and often deadly multi-organ disease. There are no drugs approved for adenovirus infections. Cidofovir (an analog of 2-deoxycytidine monophosphate) is used at times but it can be nephrotoxic and its efficacy has not been proven in clinical trials. Brincidofovir, a promising lipid-linked derivative of cidofovir, is in clinical trials. Ganciclovir, an analog of 2-deoxyguanosine, has been employed occasionally but with unknown efficacy in the clinic. In this study, we evaluated valganciclovir against disseminated adenovirus type 5 (Ad5) infection in our permissive immunosuppressed Syrian hamster model. We administered valganciclovir prophylactically, beginning 12 h pre-infection or therapeutically starting at Day 1, 2, 3, or 4 post-infection. Valganciclovir significantly increased survival, reduced viral replication in the liver, and mitigated the pathology associated with Ad5 infection. In cultured cells, valganciclovir inhibited Ad5 DNA replication and blocked the transition from early to late stage of infection. Valganciclovir directly inhibited Ad5 DNA polymerase in vitro, which may explain, at least in part, its mechanism of action. Ganciclovir and valganciclovir are approved to treat infections by certain herpesviruses. Our results support the use of valganciclovir to treat disseminated adenovirus infections in immunosuppressed patients.

  7. Vomeronasal organ lesion disrupts social odor recognition, behaviors and fitness in golden hamsters.

    PubMed

    Liu, Yingjuan; Zhang, Jinhua; Liu, Dingzhen; Zhang, Jianxu

    2014-06-01

    Most studies support the viewpoint that the vomeronasal organ has a profound effect on conspecific odor recognition, scent marking and mating behavior in the golden hamster (Mesocricetus auratus). However, the role of the vomeronasal organ in social odor recognition, social interaction and fitness is not well understood. Therefore, we conducted a series of behavioral and physiological tests to examine the referred points in golden hamster. We found that male hamsters with vomeronasal organ lesion showed no preference between a predator odor (the anal gland secretion of the Siberian weasels (Mustela sibirica) and putative female pheromone components (myristic acid and palmitic acid), but were still able to discriminate between these 2 kinds of odors. In behavioral tests of anxiety, we found that vomeronasal organ removal causes female hamsters to spend much less time in center grids and to cross fewer center grids and males to make fewer crossings between light and dark boxes than sham-operated controls. This indicates that a chronic vomeronasal organ lesion induced anxious responses in females. In aggressive behavioral tests, we found that a chronic vomeronasal organ lesion decreased agonistic behavior in female hamsters but not in males. The pup growth and litter size show no differences between the 2 groups. All together, our data suggested that vomeronasal organ ablation disrupted the olfactory recognition of social chemosignals in males, and induced anxiety-like and aggressive behavior changes in females. However, a vomeronasal organ lesion did not affect the reproductive capacity and fitness of hamsters. Our studies may have important implications concerning the role of the vomeronasal organ in golden hamsters and also in rodents. © 2013 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

  8. Pubertal testosterone organizes regional volume and neuronal number within the medial amygdala of adult male Syrian hamsters

    PubMed Central

    De Lorme, Kayla C.; Schulz, Kalynn M.; Salas-Ramirez, Kaliris Y.; Sisk, Cheryl L.

    2012-01-01

    The medial amygdala plays a key role in regulating adult social behavior and undergoes structural changes during puberty that may be driven by gonadal hormone secretion during this developmental period. The current study sought to investigate potential organizational effects of testosterone during puberty, activational effects of testosterone in adulthood, and any interactions on regional volume and neuronal number of the medial amygdala. Male Syrian hamsters either did or did not experience endogenous testosterone during pubertal brain development, and then received either testosterone-filled or blank capsules during adulthood two weeks before tissue collection. The results show that pubertal testosterone has long-term organizational effects on volume of specific subregions of the medial amygdala such that the presence of pubertal testosterone resulted in 1) decreased volume of the anterior ventral amygdala and, to a lesser extent, the anterior dorsal medial amygdala; 2) increased volume of the posterior dorsal medial amygdala. Both effects were independent of the presence of testosterone during adulthood. Pubertal testosterone also decreased neuronal number in the anterior dorsal medial amygdala, suggesting a possible mechanism by which pubertal testosterone decreases volume in this subregion. In addition, there was a significant interaction between pubertal and adult testosterone, such that testosterone in adulthood increased the number of neurons in the posterior ventral medial amygdala only in males that did not experience endogenous pubertal testosterone. In conclusion, pubertal testosterone organizes the medial amygdala in a subregion-specific manner, which may contribute to the maturation of adult-typical social behavior. PMID:22578470

  9. Molecular and Immunological Characterization of the First Allergenic Lipocalin in Hamster

    PubMed Central

    Torres, José Alberto; de las Heras, Manuel; Maroto, Aroa Sanz; Vivanco, Fernando; Sastre, Joaquín; Pastor-Vargas, Carlos

    2014-01-01

    The most frequent pet allergy is to cat and dog, but in recent years, it has become increasingly popular to have other pets, and the risk of exposure to new allergens is more prevalent. The list of new pets includes hamsters, and one of the most popular hamsters is the Siberian hamster (Phodopus sungorus). The aim of this study was the characterization and cloning of the major allergen from this hamster. The study of its allergenicity and cross-reactivity could improve the specific diagnosis and treatment for hamster-allergic patients. Thirteen Siberian hamster-allergic patients were recruited at the outpatient clinic. Protein extracts were prepared from the hair, urine, and salivary glands of four hamster species (European, golden, Siberian, and Roborovski). IgE-binding proteins were detected by immunoblotting and identified by mass spectrometry. The recombinant protein was produced in Escherichia coli and then purified by metal chelate affinity chromatography. The allergenic properties of the recombinant protein were tested by ELISA and immunoblotting, and biological activity was tested according to capacity for basophil activation. Three IgE-binding proteins were identified in extracts obtained from Siberian hamster hair, urine, and salivary glands. All proteins corresponded to the same protein, which was identified as a lipocalin. This lipocalin had no cross-reactivity with common and golden hamsters. The recombinant allergen was cloned and purified, showing similar IgE reactivity in vitro to Siberian hamster protein extracts. Also, the recombinant allergen was capable of producing biological activation in vivo. The major Siberian hamster allergen was cloned, and allergenic properties were characterized, providing a new tool for specific diagnosis of allergy to Siberian hamster. PMID:24993820

  10. Phenotypic plasticity of male Schistosoma mansoni from the peritoneal cavity and hepatic portal system of laboratory mice and hamsters.

    PubMed

    Mati, V L T; Freitas, R M; Bicalho, R S; Melo, A L

    2015-05-01

    Morphometric analysis of Schistosoma mansoni male worms obtained from AKR/J and Swiss mice was carried out. Rodents infected by the intraperitoneal route with 80 cercariae of the schistosome (LE strain) were killed by cervical dislocation at 45 and 60 days post-infection and both peritoneal lavage and perfusion of the portal system were performed for the recovery of adult worms. Characteristics including total body length, the distance between oral and ventral suckers, extension of testicular mass and the number of testes were considered in the morphological analysis. Changes that occurred in S. mansoni recovered from the peritoneal cavity or from the portal system of AKR/J and Swiss mice included total body length and reproductive characteristics. Significant morphometric alterations were also observed when worms recovered from the portal system of both strains of mice were compared with the schistosomes obtained from hamsters (Mesocricetus auratus), the vertebrate host in which the LE strain had been adapted and maintained by successive passages for more than four decades. The present results reinforce the idea that S. mansoni has high plastic potential and adaptive capacity.

  11. Siberian Ribbons

    NASA Image and Video Library

    2017-09-27

    Siberian Ribbons - June 15th, 2005 Description: Vivid colors and bizarre shapes come together in an image that could be an imaginative illustration for a fantasy story. This labyrinth of exotic features is present along the edge of Russia's Chaunskaya Bay (vivid blue half circle) in northeastern Siberia. Two major rivers, the Chaun and Palyavaam, flow into the bay, which in turn opens into the Arctic Ocean. Ribbon lakes and bogs are present throughout the area, created by depressions left by receding glaciers. Credit: USGS/NASA/Landsat 5 To learn more about the Landsat satellite go to: landsat.gsfc.nasa.gov/ NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Join us on Facebook

  12. Lesions that functionally disconnect the anterior and posterodorsal sub-regions of the medial amygdala eliminate opposite-sex odor preference in male Syrian hamsters (Mesocricetus auratus).

    PubMed

    Maras, P M; Petrulis, A

    2010-02-17

    In many rodent species, such as Syrian hamsters, reproductive behavior requires neural integration of chemosensory information and steroid hormone cues. The medial amygdala (MA) processes both of these signals through anatomically distinct sub-regions; the anterior region (MeA) receives substantial chemosensory input, but contains few steroid receptor-labeled neurons, whereas the posterodorsal region (MePD) receives less chemosensory input, but contains a dense population of steroid receptors. Importantly, these sub-regions have considerable reciprocal connections, and the goal of this experiment was therefore to determine whether interactions between MeA and MePD are required for male hamsters' preference to investigate female over male odors. To functionally disconnect MeA and MePD, males received unilateral lesions of MeA and MePD within opposite brain hemispheres. Control males received either unilateral lesions of MeA and MePD within the same hemisphere or sham surgery. Odor preferences were measured using a 3-choice apparatus, which simultaneously presented female, male and clean odor stimuli; all tests were done under conditions that either prevented or allowed contact with the odor sources. Under non-contact conditions, males with asymmetrical lesions investigated female and male odors equally, whereas males in both control groups preferred to investigate female odors. Under contact conditions, all groups investigated female odors longer than male odors, although males with asymmetrical lesions displayed decreased investigation of female odors compared to sham males. These data suggest that MeA-MePD interactions are critical for processing primarily the volatile components of social odors and highlight the importance of input from the main olfactory system (MOS) to these nuclei in the regulation of reproductive behavior. More broadly, these results support the role of the MA in integrating chemosensory and hormone information, a process that may underlie

  13. Expression of vasopressin receptors in hamster hypothalamus is sexually dimorphic and dependent upon photoperiod.

    PubMed Central

    Dubois-Dauphin, M; Theler, J M; Zaganidis, N; Dominik, W; Tribollet, E; Pévet, P; Charpak, G; Dreifuss, J J

    1991-01-01

    The distribution of vasopressin receptors was studied in the brain of a photoperiodic animal, the Siberian hamster. Attention was focused on [3H]vasopressin binding sites located in the hypothalamic ventromedial nucleus, medial tuberal nucleus, and ventral premammillary nucleus in males or females kept in long or short photoperiod conditions. Displacement experiments with structural analogs suggested that vasopressin receptors in the hamster hypothalamus are of the vasopressor (V1) type. Quantitative data obtained with a gaseous detector of beta-particles indicated that in the ventromedial nucleus and in the ventral premammillary nucleus of animals in long photoperiod, the number of beta-particles emitted per unit area was significantly greater in males than in females. In the ventromedial hypothalamic nucleus, in both males and females, the number of beta-particles emitted was significantly lower in short than in long photoperiod conditions. In the ventral premammillary nucleus, shortening of the photoperiod had a significant effect in reducing the amount of [3H]vasopressin bound in females, but not in males. These data suggest that, in the hamster, the control of the expression of vasopressin receptors differs among various hypothalamic nuclei and may depend on the sex and/or on the level of circulating gonadal steroids. Images PMID:1837144

  14. Copious urinary excretion of a male Syrian hamster (Mesocricetus auratus) salivary gland protein after its endocrine-like release upon β-adrenergic stimulation.

    PubMed

    Dubey, Ved Prakash; Srikantan, Subramanya; Mohammad, Mahabub Pasha; Rajan, Wenson David; De, Prabir Kumar

    2013-06-01

    Salivary glands, although widely considered as typically exocrine, may also release specific proteins in an endocrine manner. However, endocrine release of salivary gland proteins is not generally acknowledged since the evidences are not easily demonstrable. Submandibular salivary glands (SMG) of male Syrian hamsters express male-specific secretory proteins (MSP; which are lipocalins) visible in SDS-PAGE of SMG extracts, as major bands and also detectable in immunoblots of whole-saliva and urine as low MSP crossreactions. We report here that MSP is localized in acinar cells of SMG and acute treatment with isoproterenol (IPR; non-specific β1/β2-adrenergic agonist) results in considerable release of MSP in SMG-saliva. Moreover, acute IPR treatment markedly depletes SMG-MSP in a dose- and time-dependent manner. However, MSP depleted from SMG, far exceeds that recovered in SMG-saliva. Blood, submandibular lymph nodes and kidney of IPR-treated males showed MSP crossreactions and SDS-PAGE of their urine revealed profuse MSP excretion; this was undetectable in IPR-treated-SMG-ablated males, confirming that a substantial amount of MSP depleted from SMG after IPR treatment enters circulation and is excreted in urine. Treatments with specific β1- or β2-adrenergic agonists also reduced SMG-MSP levels and resulted in copious urinary excretion of MSP. Co-treatments with specific β1/β2-blockers indicated that above effects of IPR, β1- and even β2-agonists are very likely mediated by β1-adrenoceptors. MSP's detection by SDS-PAGE in urine after β-agonist treatment is a compelling and easily demonstrable evidence of release into circulation of a salivary gland protein. The possible means (endocrine-like or otherwise) of MSP's release into circulation and significance of its presence in saliva, blood and urine of male hamsters are discussed.

  15. Chemosensory and hormone information are relayed directly between the medial amygdala, posterior bed nucleus of the stria terminalis, and medial preoptic area in male Syrian hamsters

    PubMed Central

    Been, Laura E.; Petrulis, Aras

    2011-01-01

    In many rodent species, including Syrian hamsters, the expression of appropriate social behavior depends critically on the perception and identification of conspecific odors. The behavioral response to these odors is mediated by a network of steroid-sensitive ventral forebrain nuclei including the medial amygdala (Me), posterior bed nucleus of the stria terminalis (BNST) and medial preoptic area (MPOA). Although it is well-known that Me, BNST, and MPOA are densely interconnected and each uniquely modulates odor-guided social behaviors, the degree to which conspecific odor information and steroid hormone cues are directly relayed between these nuclei is unknown. To answer this question, we injected the retrograde tracer, cholera toxin B (CTB), into the BNST or MPOA of male subjects and identified whether retrogradely-labeled cells in Me and BNST 1) expressed immediate early genes (IEGs) following exposure to male and/or female odors or 2) expressed androgen receptor (AR). Although few retrogradely-labeled cells co-localized with IEGs, a higher percentage of BNST- and MPOA-projecting cells in the posterior Me (MeP) expressed IEGs in response to female odors than to male odors. The percentage of retrogradely-labeled cells that expressed IEGs did not, however, differ between and female- and male- odor-exposed groups in the anterior Me (MeA), posterointermediate BNST (BNSTpi), or posteromedial BNST (BNSTpm). Many retrogradely-labeled cells co-localized with AR, and a higher percentage of retrogradely-labeled MeP and BNSTpm cells expressed AR than retrogradely-labeled MeA and BNSTpi cells, respectively. Together, these data demonstrate that Me, BNST, and MPOA interact as a functional circuit to process sex-specific odor cues and hormone information in male Syrian hamsters. PMID:21316366

  16. [Resting metabolic rate, stress, testosterone, and induced immune response in "spring" and "fall" males of Campbell dwarf hamsters. Rearing under the long day conditions].

    PubMed

    2013-01-01

    We have studied morphological and physiological traits of even-young males of Campbell dwarf hamsters (Phodopus campbelli Thomas, 1905) born at the end of summer ("fall males") and at the end of winter ("spring males") in a vivarium with constant 14-hour day length (14D:10N). After removal from parental cages at the age of one month, males were kept in isolation under the same light conditions. The results obained signify the statistical difference between "fall" and "spring" males in resting metabolic rate, morphological traits associated with sexual activity, some endocrine and immunologic characteristics. Spring males had higher resting metabolic rate, higher body mass in the middle of experiment, bigger testes, seminal vesicles, higher concentration of testosterone in blood and more intensive T-cell immune response to the intracutaneous injection of phytohemagglutinin. They did not differ significantly in basal level of blood cortisole and antibodies production in response to sheep red blood cells (SRBC) antigen challenge, but possessed lower adrenocortical response to the social stressor and adrenocorticotropic hormone. GLM analysis showed that cortisol level in blood after 10 min encounter of males in the open arena, and resting metabolic rate were the only factors significantly influenced humoral immune response to SRBC. When intensity of T-cell immune response was considered as dependent variable, season turned out to be the only factor in the final model that caused a significant effect.

  17. Repeated, Intermittent Social Defeat across the Entire Juvenile Period Resulted in Behavioral, Physiological, Hormonal, Immunological, and Neurochemical Alterations in Young Adult Male Golden Hamsters.

    PubMed

    Yu, Wei-Chun; Liu, Ching-Yi; Lai, Wen-Sung

    2016-01-01

    The developing brain is vulnerable to social defeat during the juvenile period. As complements of human studies, animal models of social defeat provide a straightforward approach to investigating the functional and neurobiological consequences of social defeats. Taking advantage of agonist behavior and social defeat in male golden hamster, a set of 6 experiments was conducted to investigate the consequences at multiple levels in young adulthood resulting from repeated, intermittent social defeats or "social threats" across the entire juvenile period. Male hamsters at postnatal day 28 (P28) were randomly assigned to either the social defeat, "social threat", or arena control group, and they correspondingly received a series of nine social interaction trials (i.e., either social defeat, "social threat", or arena control conditions) from P33 to P66. At the behavioral level (Experiment 1), we found that repeated social defeats (but not "social threats") significantly impacted locomotor activity in the familiar context and social interaction in the familiar/unfamiliar social contexts. At the physiological and hormonal levels (Experiments 2 and 3), repeated social defeat significantly enhanced the cortisol and norepinephrine concentrations in blood. Enlargement of the spleen was also found in the social defeat and "social threat" groups. At the immunological level (Experiment 4), the social defeat group showed lower levels of pro-inflammatory cytokines in the hypothalamus and hippocampus but higher concentration of IL-6 in the striatum compared to the other two groups. At the neurochemical level (Experiment 5), the socially defeated hamsters mainly displayed reductions of dopamine, dopamine metabolites, and 5-HT levels in the striatum and decreased level of 5-HT in the hippocampus. In Experiment 6, an increase in the spine density of hippocampal CA1 pyramidal neurons was specifically observed in the "social threat" group. Collectively, our findings indicate that repeated

  18. Repeated, Intermittent Social Defeat across the Entire Juvenile Period Resulted in Behavioral, Physiological, Hormonal, Immunological, and Neurochemical Alterations in Young Adult Male Golden Hamsters

    PubMed Central

    Yu, Wei-Chun; Liu, Ching-Yi; Lai, Wen-Sung

    2016-01-01

    The developing brain is vulnerable to social defeat during the juvenile period. As complements of human studies, animal models of social defeat provide a straightforward approach to investigating the functional and neurobiological consequences of social defeats. Taking advantage of agonist behavior and social defeat in male golden hamster, a set of 6 experiments was conducted to investigate the consequences at multiple levels in young adulthood resulting from repeated, intermittent social defeats or “social threats” across the entire juvenile period. Male hamsters at postnatal day 28 (P28) were randomly assigned to either the social defeat, “social threat”, or arena control group, and they correspondingly received a series of nine social interaction trials (i.e., either social defeat, “social threat”, or arena control conditions) from P33 to P66. At the behavioral level (Experiment 1), we found that repeated social defeats (but not “social threats”) significantly impacted locomotor activity in the familiar context and social interaction in the familiar/unfamiliar social contexts. At the physiological and hormonal levels (Experiments 2 and 3), repeated social defeat significantly enhanced the cortisol and norepinephrine concentrations in blood. Enlargement of the spleen was also found in the social defeat and “social threat” groups. At the immunological level (Experiment 4), the social defeat group showed lower levels of pro-inflammatory cytokines in the hypothalamus and hippocampus but higher concentration of IL-6 in the striatum compared to the other two groups. At the neurochemical level (Experiment 5), the socially defeated hamsters mainly displayed reductions of dopamine, dopamine metabolites, and 5-HT levels in the striatum and decreased level of 5-HT in the hippocampus. In Experiment 6, an increase in the spine density of hippocampal CA1 pyramidal neurons was specifically observed in the “social threat” group. Collectively, our

  19. 16-Dehydropregnenolone lowers serum cholesterol by up-regulation of CYP7A1 in hyperlipidemic male hamsters.

    PubMed

    Ramakrishna, Rachumallu; Kumar, Durgesh; Bhateria, Manisha; Gaikwad, Anil Nilkanth; Bhatta, Rabi Sankar

    2017-04-01

    16-Dehydropregnenolone (DHP) has been developed and patented as a promising antihyperlipidemic agent by CSIR-Central Drug Research Institute (CSIR-CDRI), India. Although DHP is implicated in controlling cholesterol homeostasis, the mechanism underlying its pharmacological effect in hyperlipidemic disease models is poorly understood. In the present study, we postulated that DHP lowers serum lipids through regulating the key hepatic genes accountable for cholesterol metabolism. The hypothesis was tested on golden Syrian hamsters fed with high-fat diet (HFD) following oral administration of DHP at a dose of 72mg/kg body weight for a period of one week. The serum total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and total bile acids (TBA) in feces were measured. Real time comparative gene expression studies were performed for CYP7A1, LXRα and PPARα level in liver tissue of hamsters. The results revealed that the DHP profoundly decreased the levels of serum TC, TG, LDL-C and atherogenic index (AI), whilst elevated the HDL-C/TC ratio. Besides, DHP exhibited an anti-hyperlipidemic effect in the HFD induced hyperlipidemic hamsters by means of: (1) up-regulating the gene expression of CYP7A1 encoded cholesterol 7α-hydroxylase, that promotes the catabolism of cholesterol to bile acid; (2) inducing the gene expression of transcription factors LXRα and PPARα; (3) increasing the TBA excretion through feces. Collectively, the findings presented confer the hypolipidemic activity of DHP via up-regulation of hepatic CYP7A1 pathway that promotes cholesterol-to-bile acid conversion and bile acid excretion.

  20. Preventive effects of fermented brown rice and rice bran against N-nitrosobis (2-oxopropyl) amine-induced pancreatic tumorigenesis in male hamsters.

    PubMed

    Kuno, Toshiya; Takahashi, Satoru; Tomita, Hiroyuki; Hisamatsu, Kenji; Hara, Akira; Hirata, Akihiro; Kobayashi, Hiroshi; Mori, Hideki

    2015-12-01

    Fermented brown rice by Aspergillus oryzae (FBRA) is known to have the potential to prevent chemical carcinogenesis of the colon, liver, esophagus, urinary bladder, stomach and lungs in rodents. The present study examined the possible chemopreventive effects of FBRA on N-nitrosobis(2-oxopropyl)amine (BOP)-induced pancreatic tumorigenesis in hamsters. Five-week-old male Syrian golden hamsters were divided into seven groups. Groups 1-5 were subcutaneously injected with BOP (10 mg/kg body weight) four times during week 6 to induce pancreatic tumors, while groups 6 and 7 were injected with saline. Groups 2 and 3 were fed diets containing 5 and 10% FBRA, respectively, during the initiation phase. By contrast, groups 4 and 5 were fed diets containing 5 and 10% FBRA, respectively, during the post-initiation phase. Group 6 received a diet containing 10% FBRA throughout the experiment, and group 7 was kept on the basal diet alone and served as the untreated control. At the termination of the study (week 22), oral intake of 10% FBRA (group 5) during the post-initiation phase was identified to have significantly reduced the multiplicity (number of lesions/animal) of ductal adenocarcinoma [pancreatic intraepithelial neoplasia 3 (PanIN3); carcinoma in situ and invasive carcinoma] in comparison with group 1 control hamsters (0.24±0.44 vs. 0.71±0.72; P<0.05). Treatment with 10% FBRA in the post-initiation phase inhibited the progression of normal/precancerous lesions (PanIN1, mild hyperplastic lesions; and PanIN2, papillary hyperplasia) to ductal adenocarcinomas. Furthermore, dietary exposure to 10% FBRA during the initiation (group 3) and post-initiation phases (group 5) significantly reduced the multiplicity of PanIN2 (group 3, 0.55±0.69; group 5, 0.45±0.69; versus group 1, 1.26±1.24; P<0.05 and P<0.01, respectively). A significant reduction of Ki-67 positivity of PanIN2 in group 5 was also confirmed (group 5, 0.05±0.03; group 1, 0.22±0.12; P<0.01). Using terminal

  1. Preventive effects of fermented brown rice and rice bran against N-nitrosobis (2-oxopropyl) amine-induced pancreatic tumorigenesis in male hamsters

    PubMed Central

    KUNO, TOSHIYA; TAKAHASHI, SATORU; TOMITA, HIROYUKI; HISAMATSU, KENJI; HARA, AKIRA; HIRATA, AKIHIRO; KOBAYASHI, HIROSHI; MORI, HIDEKI

    2015-01-01

    Fermented brown rice by Aspergillus oryzae (FBRA) is known to have the potential to prevent chemical carcinogenesis of the colon, liver, esophagus, urinary bladder, stomach and lungs in rodents. The present study examined the possible chemopreventive effects of FBRA on N-nitrosobis(2-oxopropyl)amine (BOP)-induced pancreatic tumorigenesis in hamsters. Five-week-old male Syrian golden hamsters were divided into seven groups. Groups 1–5 were subcutaneously injected with BOP (10 mg/kg body weight) four times during week 6 to induce pancreatic tumors, while groups 6 and 7 were injected with saline. Groups 2 and 3 were fed diets containing 5 and 10% FBRA, respectively, during the initiation phase. By contrast, groups 4 and 5 were fed diets containing 5 and 10% FBRA, respectively, during the post-initiation phase. Group 6 received a diet containing 10% FBRA throughout the experiment, and group 7 was kept on the basal diet alone and served as the untreated control. At the termination of the study (week 22), oral intake of 10% FBRA (group 5) during the post-initiation phase was identified to have significantly reduced the multiplicity (number of lesions/animal) of ductal adenocarcinoma [pancreatic intraepithelial neoplasia 3 (PanIN3); carcinoma in situ and invasive carcinoma] in comparison with group 1 control hamsters (0.24±0.44 vs. 0.71±0.72; P<0.05). Treatment with 10% FBRA in the post-initiation phase inhibited the progression of normal/precancerous lesions (PanIN1, mild hyperplastic lesions; and PanIN2, papillary hyperplasia) to ductal adenocarcinomas. Furthermore, dietary exposure to 10% FBRA during the initiation (group 3) and post-initiation phases (group 5) significantly reduced the multiplicity of PanIN2 (group 3, 0.55±0.69; group 5, 0.45±0.69; versus group 1, 1.26±1.24; P<0.05 and P<0.01, respectively). A significant reduction of Ki-67 positivity of PanIN2 in group 5 was also confirmed (group 5, 0.05±0.03; group 1, 0.22±0.12; P<0.01). Using terminal

  2. Tributyltin-mediated hepatic, renal and testicular tissue damage in male Syrian hamster (Mesocricetus auratus): a study on impact of oxidative stress.

    PubMed

    Kanimozhi, V; Palanivel, K; Akbarsha, M A; Kadalmani, B

    2016-01-01

    Organotin compounds are a versatile group of organometallic chemicals that are used in a variety of industrial and agricultural applications. Tributyltin (TBT), a common organotin, brings about severe spermatotoxic and organotoxic effects. However, information about the adverse effects of TBT on liver, kidney and testis is scanty. Hence, the present study was undertaken to elucidate the TBT-mediated oxidative stress-induced impairments in these organs. Administration of TBT through oral route at increasing doses of 50, 100 and 150 ppm for 65 days to male Syrian hamsters resulted in drastically decreased activities of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase and decreased mean levels of non-enzymatic antioxidants (reduced glutathione, vitamin C, and vitamin E) followed by a dramatic increase in the levels of lipid peroxidation in the liver, kidney and testis as compared to the control animals. Significantly high levels of serum urea, creatinine, uric acid and bilirubin were observed in TBT-treated hamsters. Also, TBT treatment induced drastic histopathological changes in the liver, kidney and testis combined with remarkable changes in serum levels of tissue injury marker enzymes Aspartate transaminases, Alkaline phosphatase and Alanine transaminase. These data affirm that exposure to TBT can lead to oxidative stress-induced damage to liver, kidney and testis.

  3. The role of the medial preoptic area in appetitive and consummatory reproductive behaviors depends on sexual experience and odor volatility in male Syrian hamsters

    PubMed Central

    Been, Laura E.; Petrulis, Aras

    2010-01-01

    In Syrian hamsters (Mesocricetus Auratus), the expression of reproductive behavior requires the perception and discrimination of sexual odors. The behavioral response to these odors is mediated by a network of ventral forebrain nuclei, including the medial preoptic area (MPOA). The role of MPOA in male copulatory behavior has been well-studied, but less is known about the role of MPOA in appetitive aspects of male reproductive behavior. Furthermore, many previous studies that examined the role of MPOA in reproductive behavior have used large lesions that damaged other nuclei near MPOA or fibers of passage within MPOA, making it difficult to attribute post-lesion deficits in reproductive behavior to MPOA specifically. Thus, the current study used discrete, excitotoxic lesions of MPOA to test the role of this nucleus in opposite-sex odor preference and copulatory behavior in both sexually-naïve and sexually-experienced males. Lesions of MPOA eliminated preference for volatile, opposite-sex odors in sexually-naïve, but not sexually-experienced, males. When, however, males were allowed to contact the sexual odors, preference for female odors remained intact. Surprisingly, lesions of MPOA caused severe copulatory deficits only in sexually-naïve males, suggesting previous reports of copulatory deficits following MPOA lesions in sexually-experienced males were not due to damage to MPOA itself. Together, these results demonstrate that the role of MPOA in appetitive and consummatory aspects of reproductive behavior depends on the type of access to sexual odors and the sexual experience of the male. PMID:20732389

  4. In three brain regions central to maternal behaviour, neither male nor female Phodopus dwarf hamsters show changes in oestrogen receptor alpha distribution with mating or parenthood.

    PubMed

    Timonin, M E; Cushing, B S; Wynne-Edwards, K E

    2008-12-01

    Oestrogen receptor (ER)alpha immunoreactivity in three brain regions relevant to maternal behaviour (medial preoptic area, bed nucleus of the stria terminalis and medial amygdala) was measured in two species of dwarf hamster that both mate during a postpartum oestrous but differ in expression of paternal behaviour. Male and female Phodopus campbelli and Phodopus sungorus were sampled as sexually naive adults, following mating to satiety, and as new parents. In all brain regions, females expressed higher levels of ER alpha than males. Species did not have an effect on ER alpha distribution except in the medial amygdala, where P. sungorus females had higher expression levels than all other groups. Behavioural status was not associated with altered ER alpha expression. These results were not expected for females and suggest that a primary activational role for oestrogen, acting through ER alpha in these regions, does not generalize to maternal behaviour in Phodopus. In males, these results are consistent with previous manipulations of the ER alpha ligand, oestrogen, and suggest that paternal behaviour in P. campbelli is likely to be regulated by developmental effects of oestrogen on the brain during early life (similar to Microtus ochrogaster), rather than through activation by oestrogen at the time of fatherhood (similar to Peromyscus californicus).

  5. PSA-NCAM in the posterodorsal medial amygdala is necessary for the pubertal emergence of attraction to female odors in male hamsters.

    PubMed

    Job, Martin O; Cooke, Bradley M

    2015-09-01

    During puberty, attention turns away from same-sex socialization to focus on the opposite sex. How the brain mediates this change in perception and motivation is unknown. Polysialylated neural cell adhesion molecule (PSA-NCAM) virtually disappears from most of the central nervous system after embryogenesis, but it remains elevated in discrete regions of the adult brain. One such brain area is the posterodorsal subnucleus of the medial amygdala (MePD). The MePD has been implicated in male sexual attraction, measured here as the preference to investigate female odors. We hypothesize that PSA-NCAM gates hormone-dependent plasticity necessary for the emergence of males' attraction to females. To evaluate this idea, we first measured PSA-NCAM levels across puberty in several brain regions, and identified when female odor preference normally emerges in male Syrian hamsters. We found that MePD PSA-NCAM staining peaks shortly before the surge of pubertal androgen and the emergence of preference. To test the necessity of PSA-NCAM for female odor preference, we infused endo-neuraminidase-N into the MePD to deplete it of PSAs before female odor preference normally appears. This blocked female odor preference, which suggests that PSA-NCAM facilitates behaviorally relevant, hormone-driven plasticity.

  6. Phytosterol stearate esters elicit similar responses on plasma lipids and cholesterol absorption but different responses on fecal neutral sterol excretion and hepatic free cholesterol in male Syrian hamsters.

    PubMed

    Ash, Mark M; Hang, Jiliang; Dussault, Patrick H; Carr, Timothy P

    2011-07-01

    The dietary impact of specific phytosterols incorporated into phytosterol fatty acid esters has not been elucidated. Therefore, we tested the hypothesis that phytosterol esters containing different sterol moieties (sitosterol, sitostanol, or stigmasterol) but the same fatty acid moiety (stearic acid) produce different effects on cholesterol metabolism. Male Syrian hamsters were fed sitosterol, sitostanol, and stigmasterol stearate esters (25 g/kg diet) in an atherogenic diet containing cholesterol (1.2 g/kg) and coconut oil (80 g/kg). The phytosterol stearates produced no decrease in cholesterol absorption or plasma non-high-density lipoprotein cholesterol despite a reduction in liver free cholesterol in hamsters fed both sitosterol and sitostanol stearate diets. In addition, sitosterol stearate significantly increased fecal esterified and total neutral sterol excretion. Stigmasterol stearate did not differ from control in neutral sterol excretion, plasma lipids, or hepatic lipid concentration. Sitosterol stearate demonstrated the highest level of net intestinal hydrolysis, whereas sitostanol and stigmasterol stearate equivalently demonstrated the lowest. The cholesterol-lowering effect in liver-but not plasma-and the limited presence of fecal free sterols indicate that intact (unhydrolyzed) phytosterol stearates may impact cholesterol metabolism by mechanisms unrelated to the role of free phytosterols. The consumption of phytosterol esters at 2.5% of the diet elicited only modest impacts on cholesterol metabolism, although sitosterol stearate had a slightly greater therapeutic impact by lowering liver free cholesterol and increasing esterified and total neutral sterol fecal excretion, possibly due to a greater level of intestinal hydrolysis. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Emphysematous cholecystitis in a Siberian husky.

    PubMed Central

    Armstrong, J A; Taylor, S M; Tryon, K A; Porter, C D

    2000-01-01

    A 6-year-old, intact male Siberian husky was evaluated for a 24-hour history of vomiting and lethargy. Diagnosis of emphysematous cholecystitis was achieved based on survey abdominal radiographs, a barium contrast gastrointestinal series, and abdominal ultrasound. Diagnosis and medical and surgical management of the condition are discussed. Images Figure 1. PMID:10642874

  8. Estrogen receptor-alpha distribution in male rodents is associated with social organization.

    PubMed

    Cushing, Bruce S; Wynne-Edwards, Katherine E

    2006-02-01

    It has been hypothesized that site-specific reduction of estrogen receptor-alpha (ERalpha) is associated with the expression of male prosocial behaviors. Specifically, highly social males are predicted to express significantly lower levels of ERalpha than females and less social males in brain regions associated with prosocial behavior including the bed nucleus of the stria terminalis (BST) and the medial amygdala (MeA). This hypothesis was tested by comparing ERalpha immunoreactivity (IR) in three species of microtines, the polygynous montane (Microtus montanus) and meadow (M. pennsylvanicus) voles and the monogamous pine vole (M. pinetorum), and two species of cricetines that differ in the extent of social pair-bond formation, Siberian (Phodopus sungorus) and Djungarian (P. campbelli) hamsters. As predicted, ERalpha-IR was sexually dimorphic in the BST and MeA of the highly social species, with females expressing more ERalpha-IR cells than males. Male and female montane voles did not differ. Male and female meadow voles differed in the ventromedial hypothalamus, with females expressing more ERalpha-IR cells. Male pine voles expressed lower levels of ERalpha-IR in the MeA than male montane and meadow voles and in the BST relative to montane males. Male Djungarian hamsters, which show higher levels of parental care, had fewer ERalpha-IR cells in the BST than male Siberian hamsters. Results indicate that the distribution of ERalpha differs relative to the continuum of species-typical affiliative behavior and supports the hypothesis that ERalpha has a significant role in regulating species-specific social organization.

  9. Immediate post-defeat infusions of the noradrenergic receptor antagonist propranolol impair the consolidation of conditioned defeat in male Syrian hamsters.

    PubMed

    Gray, Cloe Luckett; Krebs-Kraft, Desiree L; Solomon, Matia B; Norvelle, Alisa; Parent, Marise B; Huhman, Kim L

    2015-12-01

    Social defeat occurs when an animal is attacked and subjugated by an aggressive conspecific. Following social defeat, male Syrian hamsters fail to display species-typical territorial aggression and instead exhibit submissive or defensive behaviors even when in the presence of a non-aggressive intruder. We have termed this phenomenon conditioned defeat (CD). The mechanisms underlying CD are not fully understood, but data from our lab suggest that at least some of the mechanisms are similar to those that mediate classical fear conditioning. The goal of the present experiment was to test the hypothesis that noradrenergic signaling promotes the consolidation of CD, as in classical fear conditioning, by determining whether CD is disrupted by post-training blockade of noradrenergic activity. In Experiment 1, we determined whether systemic infusions of the noradrenergic receptor antagonist propranolol (0, 1.0, 10, or 20mg/kg) given immediately after a 15 min defeat by a resident aggressor would impair CD tested 48 h later. Hamsters that were given immediate post-training infusions of propranolol (1.0, but not 10 or 20mg/kg) showed significantly less submissive behavior than did those given vehicle infusions supporting the hypothesis that there is noradrenergic modulation of the consolidation of a social defeat experience. In Experiment 2, we demonstrated that propranolol (1.0mg/kg) given immediately, but not 4 or 24h, after defeat impaired CD tested 48 h after defeat indicating that the window within which the memory for social defeat is susceptible to beta-adrenergic modulation is temporary. In Experiment 3, we examined whether central blockade of noradrenergic receptors could recapitulate the effect of systemic injections by giving an intracerebroventricular infusion of propranolol immediately after defeat and examining the effect on CD 24h later. Centrally administered propranolol (20 μg/3 μl but not 2 μg/3 μl) was also effective in dose-dependently reducing

  10. Immediate post-defeat infusions of the noradrenergic receptor antagonist propranolol impair the consolidation of conditioned defeat in male Syrian hamsters

    PubMed Central

    Gray, Cloe Luckett; Krebs-Kraft, Desiree L.; Solomon, Matia B.; Norvelle, Alisa; Parent, Marise B.; Huhman, Kim. L.

    2015-01-01

    Summary Social defeat occurs when an animal is attacked and subjugated by an aggressive conspecific. Following social defeat, male Syrian hamsters fail to display species-typical territorial aggression and instead exhibit submissive or defensive behaviors even when in the presence of a non-aggressive intruder. We have termed this phenomenon conditioned defeat (CD). The mechanisms underlying CD are not fully understood, but data from our lab suggest that at least some of the mechanisms are similar to those that mediate classical fear conditioning. The goal of the present experiment was to test the hypothesis that noradrenergic signaling promotes the consolidation of CD, as in classical fear conditioning, by determining whether CD is disrupted by post-training blockade of noradrenergic activity. In Experiment 1, we determined whether systemic infusions of the noradrenergic receptor antagonist propranolol (0, 1.0, 10, or 20 mg/kg) given immediately after a 15 min defeat by a resident aggressor would impair CD tested 48h later. Hamsters that were given immediate post-training infusions of propranolol (1.0, but not 10 or 20 mg/kg) showed significantly less submissive behavior than those given vehicle infusions supporting the hypothesis that there is noradrenergic modulation of social defeat consolidation. In Experiment 2, we demonstrated that propranolol (1.0 mg/kg) given immediately, but not 4 or 24h, after defeat impaired CD tested 48h after defeat indicating that the window within which the memory for social defeat is susceptible to beta-adrenergic modulation is temporary. In Experiment 3, we examined whether central blockade of noradrenergic receptors could recapitulate the effect of systemic injections by giving an intracerebroventricular infusion of propranolol immediately after defeat and examining the effect on CD 24 h later. Centrally administered propranolol (20 μg/3μl but not 2 μg/3μl) was also effective in dose-dependently reducing consolidation of CD

  11. Complete mitochondrial genome of a wild Siberian tiger.

    PubMed

    Sun, Yujiao; Lu, Taofeng; Sun, Zhaohui; Guan, Weijun; Liu, Zhensheng; Teng, Liwei; Wang, Shuo; Ma, Yuehui

    2015-01-01

    In this study, the complete mitochondrial genome of Siberian tiger (Panthera tigris altaica) was sequenced, using muscle tissue obtained from a male wild tiger. The total length of the mitochondrial genome is 16,996 bp. The genome structure of this tiger is in accordance with other Siberian tigers and it contains 12S rRNA gene, 16S rRNA gene, 22 tRNA genes, 13 protein-coding genes, and 1 control region.

  12. Time-dependent effects of dim light at night on re-entrainment and masking of hamster activity rhythms.

    PubMed

    Frank, David W; Evans, Jennifer A; Gorman, Michael R

    2010-04-01

    Bright light has been established as the most ubiquitous environmental cue that entrains circadian timing systems under natural conditions. Light equivalent in intensity to moonlight (<1 lux), however, also strongly modulates circadian function in a number of entrainment paradigms. For example, compared to completely dark nights, dim nighttime illumination accelerated re-entrainment of hamster activity rhythms to 4-hour phase advances and delays of an otherwise standard laboratory photocycle. The purpose of this study was to determine if a sensitive period existed in the night during which dim illumination had a robust influence on speed of re-entrainment. Male Siberian hamsters were either exposed to dim light throughout the night, for half of the night, or not at all. Compared to dark nights, dim illumination throughout the entire night decreased by 29% the time for the midpoint of the active phase to re-entrain to a 4-hour phase advance and by 26% for a 4-hour delay. Acceleration of advances and delays were also achieved with 5 hours of dim light per night, but effects depended on whether dim light was present in the first half, second half, or first and last quarters of the night. Both during phase shifting and steady-state entrainment, partially lit nights also produced strong positive and negative masking effects, as well as entrainment aftereffects in constant darkness. Thus, even in the presence of a strong zeitgeber, light that might be encountered under a natural nighttime sky potently modulates the circadian timing system of hamsters.

  13. Exposure to female pheromones stimulates a specific type of neuronal population in the male but not female magnocellular division of the medial preoptic nucleus (MPN mag) of the Syrian hamster.

    PubMed

    Swann, Jennifer M; Richendrfer, Holly A; Dawson, Lindsay; Nack, Elana; Whylings, Jack; Garelick, Tim

    2013-08-01

    The magnocellular division of the medial preoptic area (MPN mag) integrates pheromonal and hormonal signals to play a critical role in the expression of male typical sex behavior. The MPN mag contains two morphologically distinct neuronal populations; the percentage of each type within the nucleus is sex specific. Males have more neurons with a single nucleolus whereas females have more with multiple nucleoli. To determine which neuronal subtype mediates pheromonal induction of copulation, tissue from male and female hamsters exposed to female pheromones was immunolabeled for the immediate early protein (EGR-1). Subsequently the tissue was counterstained and the number of ERG-1 neurons with one or two nuclei was determined. The results indicate that pheromones stimulate neurons with single nucleoli in males but fail to stimulate either neuronal subtype in females suggesting that synaptic input to the MPN mag is sexually differentiated.

  14. East Siberian Sea, Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The winter sea ice in the east Siberian Sea is looking a bit like a cracked windshield in these true-color Moderate Resolution Imaging Spectroradiometer (MODIS) images from June 16 and 23, 2002. North of the thawing tundra, the sea ice takes on its cracked, bright blue appearance as it thins, which allows the reflection of the water to show through. Numerous still-frozen lakes dot the tundra. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  15. East Siberian Sea, Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The winter sea ice in the east Siberian Sea is looking a bit like a cracked windshield in these true-color Moderate Resolution Imaging Spectroradiometer (MODIS) images from June 16 and 23, 2002. North of the thawing tundra, the sea ice takes on its cracked, bright blue appearance as it thins, which allows the reflection of the water to show through. Numerous still-frozen lakes dot the tundra. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  16. The Multifrequency Siberian Radioheliograph

    NASA Astrophysics Data System (ADS)

    Lesovoi, S. V.; Altyntsev, A. T.; Ivanov, E. F.; Gubin, A. V.

    2012-10-01

    The ten-antenna prototype of the multifrequency Siberian radioheliograph is described. The prototype consists of four parts: antennas with broadband front-ends, analog back-ends, digital receivers and a correlator. The prototype antennas are mounted on the outermost stations of the Siberian Solar Radio Telescope (SSRT) array. A signal from each antenna is transmitted to a workroom by an analog fiber optical link, laid in an underground tunnel. After mixing, all signals are digitized and processed by digital receivers before the data are transmitted to the correlator. The digital receivers and the correlator are accessible by the Local Area Network (LAN). The frequency range of the prototype is from 4 to 8 GHz. Currently the frequency switching observing mode is used. The prototype data include both circular polarizations at a number of frequencies given by a list. This prototype is the first stage of the multifrequency Siberian radioheliograph development. It is assumed that the radioheliograph will consist of 96 antennas and will occupy stations of the West-East-South subarray of the SSRT. The radioheliograph will be fully constructed in the autumn of 2012. We plan to reach the brightness temperature sensitivity of about 100 K for the snapshot image, a spatial resolution up to 13 arcseconds at 8 GHz and a polarization measurement accuracy about a few percent. First results with the ten-antenna prototype are presented of observations of solar microwave bursts. The prototype's abilities to estimate source size and locations at different frequencies are discussed.

  17. Bioactivation of diethylstilbestrol by the Syrian hamster kidney

    SciTech Connect

    Adams, S.P.

    1987-01-01

    Male Syrian golden hamsters chronically exposed to diethylstilbestrol (DES) develop renal adenocarcinomas with an incidence approaching 100%. The ability of the hamster kidney to bioactivate DES was assessed using hamster kidney slices. The male hamster renal cortex has a 2- to 5-fold greater capacity to irreversibly bind ({sup 3}H)DES as compared with female hamster renal cortex and with male hamster renal medulla. Incubation of the tissue under anaerobic conditions inhibited the metabolism and irreversible binding of ({sup 3}H)DES. Gel electrophoresis analysis of covalently modified proteins revealed several radioactive peaks indicating that specific adduct formation had occurred. The cytochrome P-450 inhibitors SKF 525-A, metyrapone, carbon monoxide, butylated hydroxytoluene, and dicumarol decreased the irreversible binding of ({sup 3}H)DES to renal cortical protein by 38 to 72%.

  18. Caragana arborescens Lam.: Siberian peashrub

    Treesearch

    Donald R. Dietz; Paul E. Slabaugh; Franklin T. Bonner

    2008-01-01

    Siberian peashrub - Caragana arborescens Lam. - is one of the most hardy small deciduous trees or shrubs planted on the northern Great Plains (George 1953; Rehder 1940). Introduced into North America in 1752 (Rehder 1940), Siberian peashrub is native to Siberia and Manchuria and occurs from southern Russia to China (Graham 1941). Varieties include the dwarf (C. a. nana...

  19. Helical Siberian snakes

    SciTech Connect

    Courant, E.D.

    1988-01-01

    To eliminate spin resonances in circular accelerators ''Siberian Snakes'' may be inserted at one or more azimuths in such a way that the overall spin precession tune ..nu../sub s/ equals 1/2. A snake is a sequence of horizontal and vertical deflection magnets whose overall effect is to rotate the spin by ..pi.. about an axis in the plane of the orbit, either longitudinal or transverse or any angle /var phi/ in between. At the same time the magnets of the snake should be arranged so as to produce zero net deflection and displacement of the particle orbit. We investigate here how the orbit deflections can be made small by using helical deflecting magnets rather than discrete horizontal and vertical deflectors.

  20. Establishment and persistence of photoperiodic memory in hamsters

    PubMed Central

    Prendergast, Brian J.; Gorman, Michael R.; Zucker, Irving

    2000-01-01

    Long summer days unequivocally stimulate, and short winter days inhibit reproduction in Siberian hamsters. By contrast, intermediate-duration day lengths (12.5–14 h long) either accelerate reproductive development or initiate regression of the reproductive apparatus. Which of these outcomes transpires depends on an animal's photoperiodic history, suggesting that hamsters must encode a representation of prior photoperiods. The duration of nocturnal melatonin secretion is the endocrine representation of day length, but nothing is known about how long it takes to establish photoperiodic histories or how long they endure. Hamsters exposed for 2 or more weeks to long summer day lengths acquired a long-day photoperiodic history that determined subsequent reproductive responses to intermediate-duration day lengths and melatonin signals. The memory for long-day lengths persisted in pinealectomized hamsters for 6.5 weeks, faded significantly after 13 weeks, and was functionally absent after 20 weeks. These findings indicate that hamsters are influenced only by relatively recent day lengths and melatonin signals and ignore earlier ones that might cause them to misinterpret the salience of current day lengths. PMID:10792054

  1. Activation of oxytocin receptors, but not arginine-vasopressin V1a receptors, in the ventral tegmental area of male Syrian hamsters is essential for the reward-like properties of social interactions.

    PubMed

    Song, Zhimin; Borland, Johnathan M; Larkin, Tony E; O'Malley, Maureen; Albers, H Elliott

    2016-12-01

    Social reward plays a fundamental role in shaping human and animal behavior. The rewarding nature of many forms of social behavior including sexual behavior, parental behavior, and social play has been revealed using well-established procedures such as the conditioned place preference test. Many motivated social behaviors are regulated by the nonapeptides oxytocin (OT) and arginine vasopressin (AVP) through their actions in multiple brain structures. Interestingly, there are few data on whether OT or AVP might contribute to the rewarding properties of social interaction by their actions within brain structures that play a key role in reward mechanisms such as the ventral tegmental area (VTA). The goal of the present study was to investigate the role of OT and AVP in the VTA in regulating the reward-like properties of social interactions. Social interactions between two male hamsters reduced a spontaneous place avoidance in hamsters injected with saline control. Interestingly, however, OT and AVP injected into the VTA induced a significant two-fold reduction in place avoidance for the social interaction chamber when compared to control injections of vehicle. Finally, because OT and AVP can act on each other's receptors to influence social behavior, we also injected highly selective OTR and V1aR agonists and antagonists to determine whether OT or AVP V1a receptors were responsible for mediating the effects of these neuropeptides on social reward. Our results not only demonstrated that OT and AVP activate OTRs and not V1aRs to mediate social reward, they also demonstrated that the activation of OT receptors in the VTA is essential for the expression of the rewarding properties of social interactions.

  2. 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.

  3. Lesions of the posterior bed nucleus of the stria terminalis eliminate opposite-sex odor preference and delay copulation in male Syrian hamsters: role of odor volatility and sexual experience

    PubMed Central

    Been, Laura E.; Petrulis, Aras

    2010-01-01

    In Syrian hamsters (Mesocricetus auratus), the expression of reproductive behavior requires the perception of social odors. The behavioral response to these odors is mediated by a network of ventral forebrain nuclei, including the posterior bed nucleus of the stria terminalis (pBNST). Previous studies have tested the role of pBNST in reproductive behavior, but the use of large, fiber-damaging lesions in these studies make it difficult to attribute post-lesion deficits to pBNST specifically. Thus, the current study used discrete, excitotoxic lesions of pBNST to test the role of pBNST in opposite-sex odor preference and copulatory behavior in both sexually-naïve and sexually-experienced males. Lesions of pBNST decreased sexually-naïve males’ investigation of volatile female odors, resulting in an elimination of opposite-sex odor preference. This elimination of preference was not due to a sensory deficit, as males with pBNST lesions were able to discriminate between odors. When, however, subjects were given sexual experience prior to pBNST lesions, their preference for volatile opposite-sex odors remained intact post-lesion. Similarly, when sexually-naïve or sexually-experienced subjects were allowed to contact the social odors during the preference test, lesions of pBNST decreased males’ investigation of female odors, but did not eliminate preference for opposite-sex odors, regardless of sexual experience. Finally, lesions of pBNST delayed the copulatory sequence in sexually-naïve, but not sexually-experienced, males such that they took longer to mount, intromit, ejaculate, and display long intromissions. Together, these results demonstrate that pBNST plays a unique and critical role in both appetitive and consummatory aspects of male reproductive behaviors. PMID:20597978

  4. Siberian Pine Decline and Mortality in Southern Siberian Mountains

    NASA Technical Reports Server (NTRS)

    Kharuk, V. I.; Im, S. T.; Oskorbin, P. A.; Petrov, I. A.; Ranson, K. J.

    2013-01-01

    The causes and resulting spatial patterns of Siberian pine mortality in eastern Kuznetzky Alatau Mountains, Siberia were analyzed based on satellite (Landsat, MODIS) and dendrochronology data. Climate variables studied included temperature, precipitation and Standardized Precipitation-Evapotranspiration Index (SPEI) drought index. Landsat data analysis showed that stand mortality was first detected in the year 2006 at an elevation of 650 m, and extended up to 900 m by the year 2012. Mortality was accompanied by a decrease in MODIS derived vegetation index (EVI).. The area of dead stands and the upper mortality line were correlated with increased drought. The uphill margin of mortality was limited by elevational precipitation gradients. Dead stands (i.e., >75% tree mortality) were located mainly on southern slopes. With respect to slope, mortality was observed within a 7 deg - 20 deg range with greatest mortality occurring on convex terrain. Tree radial incrementmeasurements correlate and were synchronous with SPEI (r sq = 0.37, r(sub s) = 80). Increasing synchrony between tree ring growth and SPEI indicates that drought has reduced the ecological niche of Siberian pine. The results also showed the primary role of drought stress on Siberian pine mortality. A secondary role may be played by bark beetles and root fungi attacks. The observed Siberian pine mortality is part of a broader phenomenon of "dark needle conifers" (DNC, i.e., Siberian pine, fir and spruce) decline and mortality in European Russia, Siberia, and the Russian Far East. All locations of DNC decline coincided with areas of observed drought increase. The results obtained are one of the first observations of drought-induced decline and mortality of DNC at the southern border of boreal forests. Meanwhile if model projections of increased aridity are correct DNC, within the southern part of its range may be replaced by drought-resistant Pinus silvestris and Larix sibirica.

  5. Effects of arsenic deprivation in hamsters.

    PubMed

    Uthus, E O

    1990-01-01

    An experiment was conducted to ascertain the effects of arsenic deprivation in hamsters. Male weanling Golden Syrian hamsters were fed a casein-corn-based diet containing approximately 12 ng arsenic/g. Controls were fed 1 microgram arsenic/g of diet, as Na2HAsO4.7 H2O. After 6 weeks arsenic deprivation elevated heart weight/body weight ratio and the concentration of liver zinc and decreased the concentrations of the plasma amino acids alanine, glycine, phenylalanine and taurine. Although no biological role has been found for arsenic, the findings indicate that the hamster is a suitable animal for arsenic deprivation studies and support the hypothesis that arsenic may have a physiological role that influences methionine/methyl metabolism.

  6. Preference for bedding material in Syrian hamsters.

    PubMed

    Lanteigne, M; Reebs, S G

    2006-10-01

    This study aimed to determine whether Syrian (golden) hamsters, Mesocricetus auratus, prefer certain bedding materials and whether bedding material can affect paw condition, body weight gain and wheel-running activity. In a first experiment, 26 male hamsters had access to two connected cages, each cage containing a different bedding material (either pine shavings, aspen shavings, corn cob or wood pellets). In a second experiment, 14 male hamsters had access to four connected cages that contained the different bedding materials and also a piece of paper towel to serve as nest material. In a third experiment, 30 male hamsters were each placed in a single cage, 10 of them with pine shavings, 10 with aspen shavings and 10 with corn cob, and they were monitored for 50 days. Significant preferences in the first experiment were: pine shavings over aspen shavings, corn cob over wood pellets, pine shavings over corn cob and aspen shavings over wood pellets (aspen shavings versus corn cob was not tested). However, there was no significant preference expressed in the second experiment, suggesting that the general preference for shavings in the first experiment was based on bedding material suitability as a nesting material. No significant effect of bedding material on paw condition, body weight gain and wheel-running activity was detected. None of the four bedding materials tested in this study can be judged to be inappropriate in the short term if nesting material is added to the cage and if the litter is changed regularly.

  7. Topomineralogy of the Siberian diamonds

    NASA Astrophysics Data System (ADS)

    Afanasyev, Valentin; Lobanov, Sergey; Vasiliy, Koptil; Bogdan, Pomazanskiy; Alexander, Gerasimchuk; Nikolay, Pokhilenko

    2010-05-01

    Diamond placers are widespread in the modern alluvial deposits and ancient sedimentary collectors of the Siberian craton and can be divided into two major types: 1) related with the rich and famous kimberlites such as Mir and International pipe and 2) with unidentified root source. The lattert are wide spread, industrially significant and in use in the north-east of the Siberian craton. Yet, kimberlites known in the north-east of the Siberian craton have poor diamond concentrations or non-diamondiferous at all. A contradiction occur between high alluvial and extremely-low host diamond content of this region. Detailed studies of this problem led to the fact that diamonds from the alluvial deposits of the Siberian craton, as well as other diamondiferous regions, show broader spectrum of typomorphic features than diamonds from the known kimberlites. Moreover, some diamond groups are not typical for the phanerozoic kimberlites of Siberia, or do not occur in significant amounts. The foregoing suggests that diamonds from the unknown host rock type occur in the diamond placers of the Siberian craton along with typical kimberlite diamonds. Based on the detailed studies of the typomorphic features of the alluvial diamonds from Siberian craton 5 parasteresis groups, probably related to different host rock types, were distinguished. Parasteresis is a regular spatial mineral association which are united by single geological process, such as kimberlite indicator minerals and diamonds from kimberlites which differ in genesis but united by the whole kimberlitic process. Parasteresis 1 (kimberlite-type) involves diamonds which are common for the phanerozoic kimberlites. Parasteresis 2 (supposed to be lamproitic) includes roundish (cryptolaminar) diamonds of dodecahedron habit, the so called "brazilian" or "ural" types. In Siberian phanerozoic industrial kimberlites the part of such diamonds does not exceed 15%. That is the diamonds which dominate in the placers of the Urals and

  8. 20% PARTIAL SIBERIAN SNAKE IN THE AGS.

    SciTech Connect

    Huang, H; Bai, M; Brown, K A; Glenn, W; Luccio, A U; Mackay, W W; Montag, C; Ptitsyn, V; Roser, T; Tsoupas, N; Zeno, K; Ranjbar, V; Spinka, H; Underwood, D

    2002-11-06

    An 11.4% partial Siberian snake was used to successfully accelerate polarized proton through a strong intrinsic depolarizing spin resonance in the AGS. No noticeable depolarization was observed. This opens up the possibility of using a 20% to 30% partial Siberian snake in the AGS to overcome all weak and strong depolarizing spin resonances. Some design and operation issues of the new partial Siberian snake are discussed.

  9. Natural ligands of hamster aphrodisin.

    PubMed

    Briand, Loïc; Blon, Florence; Trotier, Didier; Pernollet, Jean-Claude

    2004-06-01

    The chemical nature of vertebrate pheromones remains largely to be deciphered. Hamster aphrodisin is a rare instance of mammal proteinaceous sexual pheromone. This protein, found in vaginal secretions, facilitates the mounting behaviour of males via activation of a specialized sensory structure named the vomeronasal organ, which activates the accessory olfactory bulb. Since it might carry small pheromonal ligands due to its lipocalin structure, we analysed organic extracts from natural aphrodisin. We identified five predominant compounds specifically bound onto natural aphrodisin as 1-hexadecanol (44.7%), 1-octadecanol (19.5%), Z-9-octadecen-1-ol (18.2%), E-9-octadecen-1-ol (15.4%) and hexadecanoic acid (2.2%). Interestingly, these compounds are also described as part of insect pheromone blends, disclosing the continuing story of amazing coincidences of chemical communication shared by mammals and insects.

  10. Corn fiber oil and sitostanol decrease cholesterol absorption independently of intestinal sterol transporters in hamsters

    USDA-ARS?s Scientific Manuscript database

    The aim of this study was to investigate the cholesterol-lowering mechanism of corn fiber oil (CFO), ferulate phytostanyl esters (FPE) and parent compounds including sitostanol and ferulic acid in hamsters. Method: Seventy male golden syrian hamsters were randomly assigned to six experimental diets ...

  11. [Comparative analysis of virulence of the Siberian and Far-East subtypes of the tick-born encephalitis virus].

    PubMed

    Pogodina, V V; Bochkova, N G; Karan', L S; Frolova, M P; Trukhina, A G; Malenko, G V; Levina, L S; Platonov, A E

    2004-01-01

    The Siberian subtype of the tick-borne encephalitis virus (TEV) is different from the Far-East subtype by a moderate virulence observed in Siberian hamsters and by a low infection development rate (100 strains were compared). No differences were found in neuro-invasiveness. Clinical findings and experiments with monkeys denote the ability of the Siberian subtype to provoke severe forms of tick-borne encephalitis (TBE). The inflammation-and-degenerative changes were localized in the brain cortex, subcortical ganglions, nuclei of medulla oblongata, in the cortex and nuclei of the cerebellum as well as in the anterior horns of the spinal cord. 18 disease cases triggered by the Siberian TEV subtypes in residents of the Western and Eastern Siberia and of Central Russia (Yaroslavl Region), including 7 acute TBE cases (5 lethal outcomes), as well as 11 chronic TBE cases are analyzed. The viral RNA was found in the cortex, medulla oblongata, horn and in the cervical part of the spinal cord of those diseased of acute TBE. Sequences of genotyped strains were presented to Gen Bank, NCBI (AY363846-AY363865).

  12. Pyometra in a Siberian Polecat (Mustela eversmanni)

    USGS Publications Warehouse

    Johnson, J.D.; Biggins, D.E.; Wrigley, R.H.; Mangone, B.A.; Wimsatt, J.

    1999-01-01

    A 2-year-old Siberian polecat (Mustela eversmanni) from a breeding colony presented for ultrasound evaluation for pregnancy. It was paired with a male for 2.75 months and had remained absent of pregnancy signs when it was anesthetized and clinically evaluated. Until this time, the animal had eaten well and shown no outward signs of debility. On palpation, the animal had a fluid-filled tubular structure in the caudal abdomen, consistent in location and size with the uterus. No sign of vaginal discharge was present. Ultrasonography revealed 10 fluid-filled evaginations (approximately 12 mm in diameter) of the uterine horns. A presumptive diagnosis of a fluid-filled reproductive tract and likely reproductive failure was made in light of the animal's history, its clinical signs, and the ultrasound findings. Euthanasia was performed because the animal was nonreproductive and might yield information relevant to the breeding colony as a whole. Necropsy of the polecat revealed a distended fluctuant uterus containing mildly odiferous, thick, yellow-green, purulent material. Histopathology confirmed the diagnosis of pyometra. A pure and heavy growth of Enterococcus fecalis was cultured from the uterine contents. In light of results from routine minimal inhibitory concentration antibiotic sensitivity screening, this isolate was resistant to all antibiotics tested in the standard teaching hospital screen.

  13. Birth of Siberian tiger (Panthera tigris altaica) cubs after transvaginal artificial insemination.

    PubMed

    Chagas e Silva, J N; Leitão, R M; Lapão, N E; da Cunha, M B; da Cunha, T P; da Silva, J P; Paisana, F C

    2000-12-01

    A captive 9-yr-old female Siberian tiger (Panthera tigris altaica) at the Lisbon Zoo was treated with equine chorionic gonadotropin followed 80 hr later by human chorionic gonadotropin to stimulate follicular development and ovulation, respectively. Forty-one hours after the second hormone administration, the tiger was subjected to transvaginal artificial insemination with diluted fresh semen containing 500 x 10(6) motile spermatozoa obtained from an 8-yr-old male Siberian tiger via electroejaculation. After anesthesia, the female tiger was placed in an inclined position with the hind limbs elevated during and after the insemination and was maintained in this position for 15 min to minimize semen reflux. An anesthetic reversal agent was then administered. After a 103-day gestation, the female gave birth to three apparently healthy cubs that survived 24-48 hr. These results demonstrate that transvaginal artificial insemination can be successfully performed in the Siberian tiger to produce full-term offspring.

  14. Spontaneous nonneoplastic lesions in control Syrian hamsters in three 24-month long-term carcinogenicity studies.

    PubMed

    McInnes, Elizabeth F; Ernst, Heinrich; Germann, Paul-Georg

    2015-02-01

    Information about the incidence of spontaneously occurring, nonneoplastic background findings in Syrian hamsters is essential if Syrian hamsters are to be used for toxicity studies. Male and female Syrian hamsters of the strain Han:AURA from the Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM) breeding colony were maintained as control animals for carcinogenicity studies and were examined for the presence of nonneoplastic background findings either when they died or when the study was terminated. The nonneoplastic background lesions observed at an incidence of >50% (high), >25% (moderate), and >10% (low) in either male or female animals or in both sexes in one or more long-term studies are detailed. The results are compared to previous published reports of nonneoplastic, spontaneous background lesions in Syrian hamsters. Background information about the incidence of background lesions in Syrian hamsters on short- and long-term studies is useful to both toxicologists and toxicological pathologists.

  15. Hamsters predisposed to sucrose-induced cholesterol gallstones (LPN strain) are more resistant to excess dietary cholesterol than hamsters that are not sensitive to cholelithiasis induction.

    PubMed

    Souidi, M; Combettes-Souverain, M; Milliat, F; Eckhardt, E R; Audas, O; Dubrac, S; Parquet, M; Férézou, J; Lutton, C

    2001-06-01

    We compared the effects of cholesterol feeding in male hamsters from two strains with different propensities to sucrose-induced cholelithiasis; Laboratoire de Physiologie de la Nutrition (LPN) hamsters are predisposed to developing biliary cholesterol gallstones, whereas Janvier (JAN) hamsters are not. When fed a basal control diet, LPN hamsters had a lower cholesterolemia (-21%, P = 0.01) than JAN hamsters, and a higher activity of 3-hydroxy-3-methyl glutaryl coenzyme A reductase in liver (+148%, P = 0.018) and intestine (+281%, P < 0.0001). After feeding the same diet enriched with 0.3% cholesterol for 5 wk, cholesterolemia increased more dramatically in JAN hamsters (+235%, P < 0.001) than in LPN hamsters (+108%, P < 0.001), as did the liver concentration of cholesterol, which reached 152.30 +/- 13.00 and 44.41 +/- 9.06 micromol/g, respectively. Only JAN hamsters displayed hepatomegaly, with an increased cholesterol saturation index of the gallbladder bile (+100%, P < 0.01), due to the cholesterol challenge. In liver, cholesterol feeding reduced cholesterol 7alpha-hydroxylase activity and mRNA level, and stimulated sterol 27-hydroxylase and oxysterol 7alpha-hydroxylase activities. Hepatic levels of LDL receptor decreased by approximately 60% in both strains, whereas HDL receptor scavenger class B type 1 (SR-BI) levels were unaffected by dietary cholesterol. The greater resistance of LPN hamsters to the hypercholesterolemic diet can be explained by a lower capacity to store cholesterol in the liver and greater efficiency in reducing the activity of 3-hydroxy-3-methyl glutaryl coenzyme A reductase in response to cholesterol feeding [from 11263 to 261 pmol/(min x organ) in LPN hamsters and from 4530 to 694 pmol/(min x organ) in JAN hamsters]. These results highlight the usefulness of this two-strain model, which offers some analogy with the inverse association between the predisposition to cholelithiasis and the risk of atherosclerosis in humans.

  16. Tamoxifen inhibits estrogen-induced hepatic injury in hamsters.

    PubMed

    Coe, J E; Ross, M J

    1988-01-01

    Estrogens have an unusual toxic effect on the liver of two hamster species, the Armenian and the Chinese hamster. The hepatotoxicity was detectable clinically by hyperbilirubinemia and confirmed histologically by the presence of hepatic degenerative-regenerative changes. Administration of tamoxifen with estrogen [either ethynyl estradiol or diethylstilbestrol (DES)] completely abrogated the hepatotoxic effects, suggesting that estrogen receptor (ER) was necessary for estrogen to damage liver. In Armenian hamsters, estrogens decreased hepatic synthesis of female protein (FP); tamoxifen also abolished this DES effect and resulted in a net increase in serum FP levels. DES administration produced higher serum bilirubin levels and lower serum FP levels in females than in males. Paradoxically, tamoxifen blocked these DES effects more effectively and efficiently in females than in males. Estrogens did not injure uteri of Armenian and Chinese hamsters and were nontoxic to livers of other hamsters species, such as Syrian and Turkish. This model provides another perspective of the acute cellular derangement that can be effected by estrogen-ER complex and may indicate a yet unknown mode of ER action.

  17. 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

  18. [Interaction of the Siberian and Far Eastern subtypes of tick-borne encephalitis virus in mammals with mixed infection. Competition of the subtypes in acute and inapparent infection].

    PubMed

    Gerasimov, S G; Pogodina, V V; Koliasnikova, N M; Karan', L S; Malenko, G V; Levina, L S

    2011-01-01

    Long-term monitoring of natural tick-borne encephalitis virus (TBEV) populations could reveal the change of TBEV subtypes, the displacement of the Far Eastern (FE) subtype, and its substitution for the Siberian (Sib) subtype. Acute and inapparent mixed infections were studied in Syrian hamsters to understand this phenomenon. The animals were inoculated with the Sib subtype and then with the FE one of TBEV (JQ845440-YaroslavI-Aver-08 and Fj214132-Kemerovo-Phateev-1954 strains). The inapparent form developed more frequently in mixed infection. Viral progeny was genotyped by reverse transcription polymerase chain reaction and hybridization fluorescence detection using genotype-specific probes. Independent reproduction of strains in the brain gave way to competition. The FE subtype dominated in hamster youngsters with acute infection. The Sib subtype had selective benefits in asymptomatic infection (adult hamsters infected intracerebrally and subcutaneously and youngsters infected subcutaneously). The competition of the subtypes was imperfect.

  19. 40Ar/39Ar dates from the West Siberian Basin: Siberian flood basalt province doubled.

    PubMed

    Reichow, Marc K; Saunders, Andrew D; White, Rosalind V; Pringle, Malcolm S; Al'Mukhamedov, Alexander I; Medvedev, Alexander I; Kirda, Nikolay P

    2002-06-07

    Widespread basaltic volcanism occurred in the region of the West Siberian Basin in central Russia during Permo-Triassic times. New 40Ar/39Ar age determinations on plagioclase grains from deep boreholes in the basin reveal that the basalts were erupted 249.4 +/- 0.5 million years ago. This is synchronous with the bulk of the Siberian Traps, erupted further east on the Siberian Platform. The age and geochemical data confirm that the West Siberian Basin basalts are part of the Siberian Traps and at least double the confirmed area of the volcanic province as a whole. The larger area of volcanism strengthens the link between the volcanism and the end-Permian mass extinction.

  20. Gait disturbances in dystrophic hamsters.

    PubMed

    Hampton, Thomas G; Kale, Ajit; Amende, Ivo; Tang, Wenlong; McCue, Scott; Bhagavan, Hemmi N; VanDongen, Case G

    2011-01-01

    The delta-sarcoglycan-deficient hamster is an excellent model to study muscular dystrophy. Gait disturbances, important clinically, have not been described in this animal model. We applied ventral plane videography (DigiGait) to analyze gait in BIO TO-2 dystrophic and BIO F1B control hamsters walking on a transparent treadmill belt. Stride length was ∼13% shorter (P < .05) in TO-2 hamsters at 9 months of age compared to F1B hamsters. Hindlimb propulsion duration, an indicator of muscle strength, was shorter in 9-month-old TO-2 (247 ± 8 ms) compared to F1B hamsters (272 ± 11 ms; P < .05). Braking duration, reflecting generation of ground reaction forces, was delayed in 9-month-old TO-2 (147 ± 6 ms) compared to F1B hamsters (126 ± 8 ms; P < .05). Hindpaw eversion, evidence of muscle weakness, was greater in 9-month-old TO-2 than in F1B hamsters (17.7 ± 1.2° versus 8.7 ± 1.6°; P < .05). Incline and decline walking aggravated gait disturbances in TO-2 hamsters at 3 months of age. Several gait deficits were apparent in TO-2 hamsters at 1 month of age. Quantitative gait analysis demonstrates that dystrophic TO-2 hamsters recapitulate functional aspects of human muscular dystrophy. Early detection of gait abnormalities in a convenient animal model may accelerate the development of therapies for muscular dystrophy.

  1. Copulatory and agonistic behavior in Syrian hamsters following social defeat.

    PubMed

    Jeffress, Elizabeth C; Huhman, Kim L

    2013-01-01

    Syrian hamsters are highly aggressive animals that reliably defend their home territory. After social defeat, however, hamsters no longer defend their home cage but instead display submissive and defensive behavior toward an intruder, a response that we have termed conditioned defeat. Plasma testosterone is significantly reduced in Syrian hamsters following repeated defeat suggesting that social defeat might also impair copulatory behavior. The present study aimed to determine whether copulatory behavior in male Syrian hamsters is suppressed following repeated social defeats and additionally whether exposure to a hormone-primed stimulus female after social defeat reduces the behavioral response to defeat. Hamsters were paired with an aggressive opponent for one or nine defeats using a resident-intruder model, while controls were placed into the empty cage of a resident aggressor. On the day after the last treatment, half of the hamsters were paired with a receptive female for 10 min. There were no significant differences in the copulatory behavior of defeated versus non-defeated hamsters, and the opportunity to copulate had no effect on subsequent conditioned defeat testing, as defeated animals displayed significantly more submissive behavior than did non-defeated animals. The current data suggest that conditioned defeat is not necessarily a maladaptive response to social stress, at least in terms of reproductive behavior, but may instead represent a viable behavioral strategy adopted by losing animals following social defeat. Further, these data indicate that conditioned defeat is relatively persistent and stable, as the opportunity to copulate does not reduce the subsequent display of submissive behavior.

  2. Developing a laboratory animal model for perinatal endocrine disruption: the hamster chronicles.

    PubMed

    Hendry, William J; Sheehan, Daniel M; Khan, Shafiq A; May, Jeffrey V

    2002-10-01

    At the biomedical, regulatory, and public level, considerable concern surrounds the concept that inappropriate exposure to endocrine-disrupting chemicals, especially during the prenatal and/or neonatal period, may disrupt normal reproductive tract development and adult function. The intent of this review was to 1. Describe some unique advantages of the hamster for perinatal endocrine disruptor (ED) studies, 2. Summarize the morphological and molecular consequences of exposure to the established perinatal ED, diethylstilbestrol, in the female and male hamster, 3. Present some new, histomorphological insight into the process of neonatal diethylstilbestrol-induced disruption in the hamster uterus, and 4. Introduce recent efforts and future plans to evaluate the potency and mechanism of action of other putative EDs in the hamster experimental system. Taken together, the findings indicate that the hamster represents a unique and sensitive in vivo system to probe the phenomenon of endocrine disruption. The spectrum of candidate endpoints includes developmental toxicity, neoplasia, and more subtle endpoints of reproductive dysfunction.

  3. Results of phenol red thread test in clinically normal Syrian hamsters (Mesocricetus auratus).

    PubMed

    Rajaei, Seyed Mehdi; Sadjadi, Reza; Sabzevari, Amin; Ghaffari, M Selk

    2013-11-01

    To determine the normal reference range for phenol red thread test (PRTT) values in clinically normal Syrian hamsters (Mesocricetus auratus). Sixteen healthy adult Syrian hamsters (eight males and eight females) were used in this study. Ophthalmic examinations were performed without chemical restraint. PRTT values were evaluated in both eyes of all Syrian hamsters using a commercial PRTT strip of a single lot number. No statistically significant differences between right and left eyes were found for any of the results. The mean ± SD PRTT values for the study population were 6.8 ± 2.5 mm/15 s with a range from 3 to 11.5 mm/15 s. Mean PRTTs in male animals were 5.1 ± 1.2 mm/15 s, whereas mean PRTTs in female hamsters were 8.5 ± 2.3 mm/15 s. Comparison between mean PRTT values in males and females showed a significant difference (P = 0.004). Mean weights for males and females were 80.9 ± 4.8 and 90.6 ± 8.5 g, respectively. No linear relationship between mean PRTT and body weight was found in female (P = 0.46) and male (P = 0.92) hamsters. This study provides novel data for normal reference ranges of PRTT values in healthy Syrian hamsters. Results of this study may assist veterinarians in the diagnosis of ocular surface disease and syndromes affecting the tear film in these species. © 2013 American College of Veterinary Ophthalmologists.

  4. Air composition over Siberian cities.

    NASA Astrophysics Data System (ADS)

    Belan, B. D.; Ivlev, G. A.; Kozlov, A. S.; Marinaite, I. I.; Peneko, V. V.; Simonenkov, D. V.; Fofonov, A. V.; Khodzher, T. V.; Arshinov, M. Yu.

    2009-04-01

    It is typical feature of Siberian cities that the quality of the atmosphere significantly depends on the climate conditions. During more than half of year, stable atmospheric stratification dominates over Siberia with temperature inversions, favoring accumulation of pollutants of different origin in the lower atmospheric layers. In addition to severe climatic conditions, modern industrial cities experience increasingly intensifying effect of anthropogenic factors on the environment and human health. Urban conditions give rise to distinct mesoclimates favoring accumulation of pollutants. In this case, natural and anthropogenic systems (power-generating and industrial objects, traffic, etc.) interact very closely. In this paper we present experimental results of the study the local air circulation effect on air composition of industrial cities of Siberian region. In our studies we have used AKV-2 mobile station, designed at the Institute of Atmospheric Optics SB RAS. The instrumentation of the station provides measurements of air temperature and humidity, wind speed and direction, total solar radiation; aerosol number density in two size ranges (0.4-10 microns by use of a modernized AZ-6 optical particle counter, and from 3 to 200 nm with a diffusion spectrometer of aerosols), and concentration of trace gases (NO, NO2, O3, SO2, CO, CO2). In addition to the continuous observations during the station motion, in Angarsk, Usol'e-Sibirskoe, Tulun, Nizhneudinsk, Taishet, Kansk, Krasnoyarsk, and Achinsk, we have carried measurements during stops at the city entry, near center, and at the exit. These observations were aimed to estimate the contribution of urban circulation to impurity accumulation on the city territory and to the change of thermodynamic regime. Such a contribution was found in all of the above-mentioned cities. Maximum of NO concentration is observed at crossroads of the main highways and decreases away from them. It should be noted that the NO distribution

  5. Body weight as a determinant of clinical evolution in hamsters (Mesocricetus auratus) infected with Leishmania (Viannia) panamensis.

    PubMed

    Gómez-Galindo, Angela María; Delgado-Murcia, Lucy Gabriela

    2013-01-01

    The clinical outcome of infection with Leishmania species of the subgenus Viannia in hamster model (Mesocricetus auratus) has shown to be different depending on experimental protocol. Body weight has been a relevant determinant of the clinical outcome of the infection in hamsters with visceral leishmaniasis but its importance as a clinical parameter in hamsters with cutaneous leishmaniasis is not known. In this study, the clinical evolution of infection with L. (V) panamensis was evaluated in juvenile and adult male hamsters during 11 weeks by comparing clinical parameters such as attitude, temperature, respiratory rate, appearance of the stool, and body weight between infected and non-infected groups. Results showed that body weight decreased in adult hamsters after infection by L. (V) panamensis; this observation supports the use of body weight as an additional parameter to define the management or treatment of cutaneous leishmaniasis in infected adult hamsters used as an animal experimental model for leishmaniasis.

  6. Gender effects of tall oil versus soybean phytosterols as cholesterol-lowering agents in hamsters.

    PubMed

    Ntanios, F Y; MacDougall, D E; Jones, P J

    1998-01-01

    To examine the effect of gender on the mechanisms of action of phytosterols extracted from tall oil (TO) and soybean (SB) on cholesterol and phytosterol metabolism, male and female hamsters were fed cholesterol-enriched diets containing 0.5 or 1% (w/w) TO or SB phytosterols for 90 days. Plasma lipoprotein cholesterol profile and tissue phytosterol and cholesterol biosynthesis levels were determined. Mean plasma total-cholesterol level in females fed 1% (w/w) SB was reduced (p<0.05) by 44%, while in males it was lowered (p<0.05) by 25% compared with their respective controls. Moreover, mean plasma total-cholesterol level was reduced (p<0.05) in male hamsters by -31% and female hamsters by -32% when fed 1% (w/w) TO. Cholesterol biosynthesis was higher (p<0.05) by twofold in groups fed TO at 0.5 and 1% (w/w) concentrations, compared with SB. Hamsters fed TO at 0.5 and 1% (w/w) levels also had higher (p<0.05) hepatic and enterocytic campesterol contents than SB-fed animals. These findings demonstrate gender differences in cholesterol metabolism in TO- and SB-fed hamsters. The results suggest that TO, conversely to SB phytosterol, is a more effective cholesterol-lowering agent in male, but not as much in female, hamsters, over a feeding period of 90 days.

  7. Characterization of a siberian virus isolated from a patient with progressive chronic tick-borne encephalitis.

    PubMed

    Gritsun, T S; Frolova, T V; Zhankov, A I; Armesto, M; Turner, S L; Frolova, M P; Pogodina, V V; Lashkevich, V A; Gould, E A

    2003-01-01

    A strain of Tick-borne encephalitis virus designated Zausaev (Za) was isolated in Siberia from a patient who died of a progressive (2-year) form of tick-borne encephalitis 10 years after being bitten by a tick. The complete genomic sequence of this virus was determined, and an attempt was made to correlate the sequence with the biological characteristics of the virus. Phylogenetic analysis demonstrated that this virus belongs to the Siberian subtype of Tick-borne encephalitis virus. Comparison of Za virus with two related viruses, a Far Eastern isolate, Sofjin, and a Siberian isolate, Vasilchenko, revealed differences among the three viruses in pathogenicity for Syrian hamsters, cytopathogenicity for PS cells, plaque morphology, and the electrophoretic profiles of virus-specific nonstructural proteins. Comparative amino acid alignments revealed 10 individual amino acid substitutions in the Za virus polyprotein sequence that were different from those of other tick-borne flaviviruses. Notably, the dimeric form of the Za virus NS1 protein migrated in polyacrylamide gels as a heterogeneous group of molecules with a significantly higher electrophoretic mobility than those of the Sofjin and Vasilchenko viruses. Two amino acid substitutions, T(277)-->V and E(279)-->G, within the NS1 dimerization domain are probably responsible for the altered oligomerization of Za virus NS1. These studies suggest that the patient from whom Za virus was isolated died due to increased pathogenicity of the latent virus following spontaneous mutagenesis.

  8. Asymptomatic anomalous pulmonary veins in a Siberian Husky.

    PubMed

    Abraham, L A; Slocombe, R F

    2003-07-01

    A 2-year-old, neutered male Siberian Husky presented with depression, weight loss and an inability to prehend food and water. Cerebrospinal fluid was collected under general anaesthesia prior to euthanasia. The elevated white cell count comprised mostly mononuclear cells. Histological changes within the brain were variable and multifocal. Non-suppurative meningitis secondary to lymphoma was diagnosed. At necropsy, abnormal venous drainage of the right cranial and middle lung lobes was found. A dilated major pulmonary vein from these lobes passed across the lateral aspect of the right caudal lung lobe prior to entering the heart, and subpleural veins from the affected lobes were enlarged and tortuous. These vascular abnormalities were considered incidental. There were no apparent congenital abnormalities of the heart and the animal's clinical signs were related to lymphoma of the brain.

  9. [Identification and production of monoclonal antibody of Siberian tiger's immunoglobulin].

    PubMed

    Zhang, Yaonglong; Zhang, Duanling; Zhou, Ming; Xue, Yuan; Hua, Yuping; Ma, Jianzhang

    2010-03-01

    To purify immunoglobulin (Ig) of Siberian Tiger and prepare monoclonal antibody (mAb) against the Ig,which can be used to develop immunological diagnostic kits for diagnosing infectious disease in Siberian Tiger. The Ig of Siberian tigers was purified with saturated ammonium sulfate combined with recombinant Protein G. The C57BL/6 mice were immunized with the purified Ig. Spleno-cytes of the mice immunized were collected and fused with the mouse myeloma cell line (Sp2/0-Ag14). The positive hybridoma clones were selected by ELISA and were identified by western blot. The sandwich ELISA was used to detect immunocompetence of the purified Ig and the mAb. We obtained three mouse hybridoma clones that produced mAbs against Ig of Siberian Tiger. The derived McAbs could recognize Ig heavy chain of Siberian Tiger specifically. The biological activity of the Ig and obtained McAbs also could be identified by detecting the antibody induced by panleukopenia virus (FPV-HLJ) vaccine in Siberian Tiger. The antibody also would be useful for assess the vaccine efficacy against the infectious disease on the Siberian Tiger. Protein G can be used in Ig purification of Siberian Tiger. The obtained McAbs from the hybridoma ADT11 in this study owned strong ability to bind Ig of Siberian Tiger and have a stable immunocompetence. They can be used to develop diagnostic methods for detecting infectious disease in Siberian Tiger and vaccine research.

  10. Behavioural and endocrinological changes in Syrian hamsters (Mesocricetus auratus) under domestication.

    PubMed

    Krause, S; Schüler, L

    2010-12-01

    This study aimed to quantify differences in response to stress between two strains of Syrian hamsters to evaluate the consequences of domestication in this species by measuring behavioural traits in the open-field, adrenal gland masses (ADR), and faecal and blood corticosterone concentrations (CC). We studied a laboratory (lab)- and a wild-derived population (wild). The lab hamsters were significant heavier than the wild hamsters. The lab males had the highest ADR, and it was independent of their high body mass (BM). The ADR of lab females and wild hamsters was linearly dependent of BM. The lab males had the highest faecal and blood CC, whereas the lab females had the lowest CC. In the open field, the lab hamsters began later to groom, groomed shorter, groomed less frequently, began later to rear, reared longer and reared less frequently. In the lab population, females reared more often and groomed longer than males. The sex differences in the behaviours of the lab population and the differences between the populations mirror the differences neither in the ADR nor in the CC. The founder effect and the breeding history of lab Syrian hamsters are discussed as causes of the differences between the studied populations.

  11. [Interaction of the Siberian and Far Eastern subtypes of tick-borne encephalitis virus in mammals with mixed infection. I. Factors influencing the type of interaction].

    PubMed

    Gerasimov, S G; Pogodina, V V; Kolyasnikova, N M; Karan, L S; Malenko, G V; Levina, L S

    2011-01-01

    Polytypic strains containing the fragments of genes of Siberian and Far Eastern tick-borne encephalitis (TBE) virus subtypes were isolated from the brain of fatal TBE patients, the blood of TBE patients, and Ixodes persulcatus ticks in the foci of concomitant circulation of the two subtypes. The interaction of the Siberian and Far Eastern TBE virus subtypes was studied in the neural phase of the infection of albino mice and Syrian hamsters in order to understand conditions for formation of these strains and their role in the etiology of acute TBE. Their viral progeny was genotyped by reverse transcription-polymerase chain reaction and fluorescence hybridization assay with genotype-specific probes. Mixed infection showed an effect of synergism, independent reproduction of the two subtypes in the brain and spleen, competitive exclusion of one subtype from the viral population. The type of the Interaction depended on the species of animals, the properties of partner strains, and the target organ.

  12. On- Offshore correlation around the New Siberian Islands, Laptev and East Siberian Seas, Russian Arctic

    NASA Astrophysics Data System (ADS)

    Franke, D.; Piepjohn, K.; Gaedicke, C.; Brandes, C.; Sobelev, N.; Mouly, B.

    2012-04-01

    The Laptev and East Siberian Seas cover large areas of the continental margin of North-Eastern Siberia and are separated by the New Siberian Islands. The East Siberian Shelf covering an area of 935.000 km2 is a virtually unexplored area and most geological models for this shelf are extrapolations of the geology of the New Siberian Islands, the Wrangel Island and the northeast Siberia landmass. Apart from few seismic reflection lines airborne magnetic data were the primary means of deciphering the structural pattern of the East Siberian Shelf. The Laptev Shelf covers an area of about 660.00 km2 and occupies a shelf region, where the active mid-oceanic spreading ridge of the Eurasia Basin meets the slope of a continental margin. Since no deep wells have been drilled so far on the shelves surrounding the New Siberian Islands, the precise age and nature of the seismic horizons which have been defined remain uncertain. All interpretations base on different evolution scenarios for the shelf areas resulting in a wide variety of interpretations available for the sedimentary cover of the Laptev Shelf where the interpretations range from Proterozoic to Cenozoic. Here we present correlations from onshore to offshore geology based on multichannel reflection seismic data acquired by BGR in the 1990th and a joint VSEGEI/BGR expedition to the New Siberian Islands in 2011. Key marker horizons in the offshore data are linked to major hiatuses in the onshore region. Well information is available close by the Lena delta in the form of sketched stratigraphy ranging from Proterozoic to Cretaceous. Both informations can be reconciled on a cross section despite a gap of approximately 25km, providing a tentative age for a regional unconformity sitting on top of an acoustic basement. We additionally reinterpret the stratigraphy based on rift stages at the conjugate North Greenland margin. Thus we suggest the presence of a break-up unconformity in the seismic data.

  13. Daily Profile of the Extracellular Concentration of Glutamate in the Suprachiasmatic Region of the Siberian Hamster

    DTIC Science & Technology

    1993-01-01

    in nant excitatory transmitter in neuroendocrine regulation . Science the optic nerve to the suprachiasmatic nucleus in slices of...physiologic and behavioral rhythms in main- (RHT), and an indirect retinal projection through the mals (1, 2). In rodents, bilateral destruction or... rhythm following suprachiasmatic lesions in the rat. Brain Res the possibility that the high levels of

  14. Hyperadrenocorticism in Three Teddy Bear Hamsters

    PubMed Central

    Bauck, L. (Brouwer); Orr, J. P.; Lawrence, K. H.

    1984-01-01

    Hyperadrenocorticism was diagnosed in three related teddy bear hamsters with presenting complaints of alopecia and hyperpigmentation of the skin. Treatment was attempted in two of the hamsters and was successful in one case. Metyrapone and o,p′-DDD (1,1-dichloro-2-2bis (p-chlorophenyl) ethane) were the drugs used. Necropsy and histopathological examinations revealed a pituitary chromophobe adenoma in one hamster and an adrenocortical adenocarcinoma in a second hamster. The third related hamster was clinically diagnosed as having hyperadrenocorticism but the origin of the disease has not yet been determined. ImagesFigure 1.Figure 2.Figure 3.Figure 4.Figure 5. PMID:17422415

  15. Hyperadrenocorticism in three teddy bear hamsters.

    PubMed

    Bauck, L B; Orr, J P; Lawrence, K H

    1984-06-01

    Hyperadrenocorticism was diagnosed in three related teddy bear hamsters with presenting complaints of alopecia and hyperpigmentation of the skin. Treatment was attempted in two of the hamsters and was successful in one case. Metyrapone and o,p'-DDD (1,1-dichloro-2-2bis (p-chlorophenyl) ethane) were the drugs used. Necropsy and histopathological examinations revealed a pituitary chromophobe adenoma in one hamster and an adrenocortical adenocarcinoma in a second hamster. The third related hamster was clinically diagnosed as having hyperadrenocorticism but the origin of the disease has not yet been determined.

  16. Effects of lectins with various carbohydrate binding specificities on lipid metabolism in isolated rat and hamster adipocytes.

    PubMed

    Ng, T B; Li, W W; Yeung, H W

    1989-01-01

    1. Mannose-binding and N-acetylglucosamine binding lectins exhibited potent antilipolytic and lipogenic activities. 2. Fucose-binding lectins had minimal lipogenic activity but possessed antilipolytic activity. 3. Most galactose-binding and N-acetylgalactosamine-binding lectins were devoid of significant antilipolytic and lipogenic activities. Notable exceptions were lectins from Momordica charantia, Wisteria floribunda, Vicia villosa, Codium fragile and the Siberian pine tree. lipogenic activity but lacked antilipolytic activity. 5. The galactose-binding horse gram and osage orange lectins exerted antilipolytic activity in hamster but not in rat adipocytes.

  17. Proximity to Intrinsic Depolarizing Resonances with a Partial Siberian Snake

    NASA Astrophysics Data System (ADS)

    Crandell, D. A.; Alexeeva, L. V.; Anferov, V. A.; Blinov, B. B.; Chu, C. M.; Caussyn, D. D.; Courant, E. D.; Gladycheva, S. E.; Hu, S.; Krisch, A. D.; Nurushev, T. S.; Phelps, R. A.; Ratner, L. G.; Varzar, S. M.; Wong, V. K.; Derbenev, Ya. S.; Lee, S. Y.; Rinckel, T.; Schwandt, P.; Sperisen, F.; Stephenson, E. J.; von Przewoski, B.; Baiod, R.; Russell, A. D.; Ohmori, C.; Sato, H.

    1996-05-01

    Partial Siberian snakes are effective in overcoming imperfection depolarizing resonances, but they may also change the crossing energy for intrinsic depolarizing resonances. We experimentally investigated the effect of a partial Siberian snake near intrinsic depolarizing resonances with stored 140 MeV and 160 MeV polarized proton beams. Using various partial Siberian snake strengths up to 30%, depolarization was observed; this may be due to a change in the spin precession frequency which moves the energy of nearby intrinsic depolarizing resonances.

  18. Hydrogeology of the West Siberian Basin

    SciTech Connect

    Foley, M.G.; Bradley, D.J.; Cole, C.R.

    1996-08-01

    Nuclear fuel cycle activities of the former Soviet Union (FSU) have resulted in extensive radioactive contaminant releases to the environment in western Siberia. We are developing three-dimensional numerical models of the hydrogeology and potential contaminant migration in the West Siberian Basin. We have assumed that ground-water flow in the West Siberian Basin is topographically driven, with recharge to the basin occurring in the highlands on the west, east, and south, and internal discharge localized in numerous river valleys and lakes that ultimately discharge north to the ocean. We are modeling the regional hydrogeology as three-dimensional, steady-state, saturated flow that is recharged from above. We acquired topographic, geologic, hydrostratigraphic, hydrogeologic, and water-balance data for the West Siberian Basin and constructed a regional water table. We correlated and combined 70 different rock types derived from published descriptions of West Siberian Basin rocks into 17 rock types appropriate for assignment of hydrogeologic properties on the basis of spatial heterogeneity and constituent (i.e., sand, silt, and clay) diversity. Examination of resulting three-dimensional assemblages of rock types showed that they were consistent with published and inferred paleogeography and depositional processes. Calibrating the basin`s moisture balance (i.e., recharge and discharge) to the derived water table determined plausible input parameter values for unknowns such as hydraulic conductivities. The general directions of calculated ground-water flow suggest that major rivers act as discharge areas, with upwelling below the rivers extending down into the basement rocks, and that ground-water divides that penetrate the entire thickness of the model are evident between major rivers.

  19. Lena River Delta and East Siberian Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The winter sea ice in the east Siberian Sea is looking a bit like a cracked windshield in these true-color Moderate Resolution Imaging Spectroradiometer (MODIS) images from June 16 and 23, 2002. North of the thawing tundra, the sea ice takes on its cracked, bright blue appearance as it thins, which allows the reflection of the water to show through. Numerous still-frozen lakes dot the tundra. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  20. Diazepam enhances conditioned defeat in hamsters (Mesocricetus auratus).

    PubMed

    Hebert, M A; Potegal, M; Moore, T; Evenson, A R; Meyerhoff, J L

    1996-11-01

    Male hamsters that have been repeatedly defeated by larger, aggressive males subsequently flee from, rather than attack, nonaggressive male intruders that are introduced into their home cages. We have referred to this generalization of flight in response to nonaggressive intruders as "conditioned defeat" (CD). In an attempt to reverse CD pharmacologically, diazepam (DZP) was administered to hamsters at two different time points relative to CD acquisition and subsequent response generalization tests, which involved the exposure of subjects to nonaggressive intruders (NAIs). In Experiment 1, subjects were given a single injection of one of 4 doses of DZP (0, 2, 6, or 20 mg/kg) immediately following CD acquisition. Twenty-four hours later, contrary to expectations, subjects that had received the 6 mg/kg dose displayed elevated flight responses in the presence of an NAI. Flight responding declined over days except in subjects that received the highest dose. In the second experiment, hamsters were administered a single injection of either 0, 2, or 6 mg/kg DZP just prior to a response generalization test occurring 24 h following CD training. Flight responses to the NAIs were again exaggerated in subjects that were given the 6 mg/kg dose, an effect that persisted several days without further drug administration. The present findings suggest the possibility that benzodiazepines can potentiate fear responses under certain stressful conditions.

  1. Climate constraints for siberian moth distribution in Europe

    Treesearch

    Yuri Baranchikov; Nadezda Tschebakova; Elena Parfenova; Natalia. Kirichenko

    2010-01-01

    A simplistic bioclimatic model of the Siberian moth Dendrolimus sibiricus Tschtvrk. (Lepidoptera: Lasiocampidae) is based on the moth's basic biological requirements, expressed through summer thermal conditions...

  2. The emergence of obesity among indigenous Siberians.

    PubMed

    Snodgrass, J Josh; Leonard, William R; Sorensen, Mark V; Tarskaia, Larissa A; Alekseev, Vasili P; Krivoshapkin, Vadim

    2006-01-01

    Once considered a disease of affluence and confined to industrialized nations, obesity is currently emerging as a major health concern in nearly every country in the world. Available data suggest that the prevalence rate of obesity has reached unprecedented levels in most developing countries, and is increasing at a rate that far outpaces that of developed nations. This increase in obesity has also been documented among North American circumpolar populations and is associated with lifestyle changes related to economic development. While obesity has not been well studied among indigenous Siberians, recent anthropological studies indicate that obesity and its associated comorbidities are important health problems.The present study examines recent adult body composition data from four indigenous Siberian populations (Evenki, Ket, Buriat, and Yakut) with two main objectives: 1) to determine the prevalence of overweight and obesity among these groups, and 2) to assess the influence of lifestyle and socioeconomic factors on the development of excess body fat. The results of this study indicate that obesity has emerged as an important health issue among indigenous Siberians, and especially for women, whose obesity rates are considerably higher than those of men (12% vs. 7%). The present study investigated the association between lifestyle and body composition among the Yakut, and documented substantial sex differences in lifestyle correlates of obesity. Yakut men with higher incomes and who owned more luxury consumer goods were more likely to have excess body fat while, among Yakut women, affluence was not strongly associated with overweight and obesity.

  3. Cambrian trilobites with Siberian affinities, southwestern Alaska

    SciTech Connect

    Palmer, A.R.; Egbert, R.M.; Sullivan, R.; Knoth, J.S.

    1985-02-01

    Cambrian trilobites occur in two levels (about 7 m apart) in the core of a large, complex anticlinal structure in the area between the Taylor Mountains and the Hoholitna River in southwestern Alaska. The lower collection contains Erbia, Macannaia (a species close to Soviet forms described as Pagetia ferox Lermontova), two species of Kootenia (including one perhaps cospecific with forms from the central Brooks range), and several species of ptychoparioid trilobites. It is clear that biogeographic affinities are with the transitional facies of the eastern Siberian platform and the south Siberian foldbelt. In Soviet terms, the age of the collection falls in a disputed interval called latest Early Cambrian (Tojonian) by some authors, and earliest Middle Cambrian (Amgan) by others. In North American terms, Macannaia is known only from early Middle Cambrian beds. The younger collection contains abundant agnostids, a variety of conocoryphids, Paradoxides, and several species of ptychoparioid trilobites. This is an assemblage of undoubted late Middle Cambrian age, comparable to faunas described from the Maya State of the Siberian platform and the Paradoxides paradoxissimus Stage of the Baltic region. Both faunas are from ocean-facing or outer shelf environments. None of the key non-agnostid or non-pagetiid elements have been seen previously in deposits of Cambrian North America.

  4. Arginine-vasopressin and the regulation of aggression in female Syrian hamsters (Mesocricetus auratus).

    PubMed

    Gutzler, Stephanie J; Karom, Mary; Erwin, W D; Albers, H E

    2010-05-01

    Arginine-vasopressin (AVP) is critical for the expression of a variety of social behaviors in many species. Previous studies have demonstrated that AVP regulates behaviors such as social communication and aggression in Syrian hamsters through the V1a receptor subtype. In male hamsters, AVP injected into the anterior hypothalamus (AH) stimulates aggression, while injection of a V1a receptor antagonist inhibits the behavior. The purpose of the present studies was to determine whether AVP influences aggression by its action in the AH in female hamsters. In the first experiment, we were surprised to find that injection of the V1a receptor antagonist, Manning compound, into the AH of intact female hamsters increased aggression. The second experiment confirmed the ability of the V1a receptor antagonist to increase aggression and found that the largest effects of the antagonist occurred at intermediate concentrations of the compound. The next experiment found that injection of AVP into the AH significantly reduced the latency to attack and the duration of aggression. Finally, we examined whether the effects of AVP and the V1a receptor antagonist on aggression differed in hamsters exposed to long 'summer-like' photoperiods or short 'winter-like' photoperiods, and found that their effects on aggression were not photoperiod dependent. In summary, contrary to what is observed in males, these data suggest that AVP in the AH may play an inhibitory role on aggression in female Syrian hamsters.

  5. Effect of exercise on photoperiod-regulated hypothalamic gene expression and peripheral hormones in the seasonal Dwarf Hamster Phodopus sungorus.

    PubMed

    Petri, Ines; Dumbell, Rebecca; Scherbarth, Frank; Steinlechner, Stephan; Barrett, Perry

    2014-01-01

    The Siberian hamster (Phodopus sungorus) is a seasonal mammal responding to the annual cycle in photoperiod with anticipatory physiological adaptations. This includes a reduction in food intake and body weight during the autumn in anticipation of seasonally reduced food availability. In the laboratory, short-day induction of body weight loss can be reversed or prevented by voluntary exercise undertaken when a running wheel is introduced into the home cage. The mechanism by which exercise prevents or reverses body weight reduction is unknown, but one hypothesis is a reversal of short-day photoperiod induced gene expression changes in the hypothalamus that underpin body weight regulation. Alternatively, we postulate an exercise-related anabolic effect involving the growth hormone axis. To test these hypotheses we established photoperiod-running wheel experiments of 8 to 16 weeks duration assessing body weight, food intake, organ mass, lean and fat mass by magnetic resonance, circulating hormones FGF21 and insulin and hypothalamic gene expression. In response to running wheel activity, short-day housed hamsters increased body weight. Compared to short-day housed sedentary hamsters the body weight increase was accompanied by higher food intake, maintenance of tissue mass of key organs such as the liver, maintenance of lean and fat mass and hormonal profiles indicative of long day housed hamsters but there was no overall reversal of hypothalamic gene expression regulated by photoperiod. Therefore the mechanism by which activity induces body weight gain is likely to act largely independently of photoperiod regulated gene expression in the hypothalamus.

  6. Plasma and hepatic cholesterol-lowering in hamsters by tomato pomace, tomato seed oil and defatted tomato seed supplemented in high fat diets

    USDA-ARS?s Scientific Manuscript database

    We determined the cholesterol-lowering effects of tomato pomace (TP), a byproduct of tomato processing, and its components such as tomato seed oil (TSO) and defatted tomato seed (DTS) in hamsters, a widely used animal model for cholesterol metabolism. Male Syrian Golden hamsters were fed high-fat di...

  7. Effects of single and repeated inhalation exposure of Syrian hamsters to aerosols of /sup 144/CeO/sub 2/

    SciTech Connect

    Lundgren, D.L.; Hahn, F.F.; McClellan, R.O.

    1982-05-01

    Male Syrian hamsters (84 days old at the time of the initial exposure) were repeatedly exposed by inhalation at approximately 60-day intervals for 1 year (seven exposures) to aerosols of /sup 144/CeO/sub 2/ to reestablish lung burdens of 0.4, 2.0, or 10 ..mu..Ci of /sup 144/Ce. Other hamsters were exposed once when either 84, 220, or 360 days old to achieve similar initial lung burdens. Primary lung tumors were observed in 7 of 197 hamsters repeatedly exposed to /sup 144/CeO/sub 2/ that died between 177 and 685 days after the initial inhalation exposure. The cumulative adsorbed ..beta..-radiation doses to the lungs of these hamsters were 14,000 to 50,000 rad. Primary lung tumors also were observed in 6 of 153 hamsters exposed once to /sup 144/CeO/sub 2/ when 84 or 220 days old that died between 270 and 695 days after exposure. The cumulative ..beta..-radiation doses to the lungs of these hamsters were 6000 to 21,000 rad. Lung tumors were not observed in hamsters exposed when 360 days old or in control hamsters. The incidences of primary lung tumors were more dependent on the cumulative dose to the lung than the radiation dose pattern that resulted in the cumulative dose.

  8. Mantle density structure of the Siberian craton and the West Siberian basin

    NASA Astrophysics Data System (ADS)

    Cherepanova, Y. V.; Artemieva, I. M.

    2013-12-01

    We present a mantle density model of the Proterozoic- Paleozoic West Siberian basin (WSB) and the Archean -Proterozoic Siberian craton (SC) based on free-board constraints. Given complex tectonic evolution of both WSB and SC, a strong compositional heterogeneity of mantle lithosphere is expected, but has never been documented so far in regional geophysical studies. In particular, the Siberian craton, formed by amalgamation of Archean terranes, has been significantly affected by Proterozoic collisional and extensional events, Devonian rifting of the Vilyui rift, and several pulses of kimberlite magmatism. The basement of the West Siberian basin, the largest in the world intracontinental basin, was formed by amalgamation of island arcs, terranes, micro-continents, and relict ocean basins during late Proterozoic-Paleozoic orogenic events, and was later affected by the Permian-early Triassic rifting, followed by emplacement of the Siberian traps, which cover much of the SC and the WSB. Their source region and geodynamic origin are still a subject of debate, although a strong reworking of the lithosphere is expected to be associated with the Siberian LIP. The present-day West Siberian basin and the Siberian craton lack significant surface topography variations, whereas the crustal structure is highly heterogeneous with large lateral variations in crustal thickness (ca. 20 km), thickness of sediments (ca. 15 km), and average crustal density (Cherepanova et al., 2013). Similarly, thermal regime of the lithosphere is also heterogeneous, ranging from typical cold cratonic geotherms in much of the SC with up-to 350 km thick lithosphere to hot geotherms in the rifted part of the WSB, where the lithosphere thickness is ca. 90-130 km (Artemieva and Mooney, 2001). Nonetheless, free air gravity is near-zero for much of Siberia suggesting that it is close to isostatic equilibrium. Topography, through the lithosphere buoyancy, is controlled by the structure of the mantle

  9. Cystolithiasis in a Syrian hamster: a different outcome

    PubMed Central

    Petrini, D.; Di Giuseppe, M.; Deli, G.; De Caro Carella, C.

    2016-01-01

    A 14-month-old intact male Syrian hamster was admitted for lethargy and hematuria. A total body radiographic image and abdominal ultrasonography showed the presence of a vesical calculus. During cystotomy, a sterile urine sample was obtained and sent to the diagnostic laboratory along with the urolith for analysis. Urine culture was found negative for bacterial growth, and the urolith was identified as a calcium-oxalate stone. Diet supplementation with palmitoylethanolamide, glucosamine and hesperidin was adopted the day after discharge. One year follow up revealed no presence of vesical calculi. Although this is the report of a single clinical case, this outcome differs from the results reported in the literature characterized by recurrences after few months. Considering the positive outcome and the beneficial properties of palmitoylethanolamide, glucosamine, and hesperidin, these nutritional elements in Syrian hamsters, are recommended to reduce recurrence after surgical treatment of urolithiasis. PMID:27540515

  10. Hydrogeology of the West Siberian Basin

    SciTech Connect

    Hoover, K.A.; Foley, M.G.; Bradley, D.J.

    1996-12-31

    Nuclear fuel cycle activities of the former Soviet Union (FSU) have resulted in significant contamination of the environment in western Siberia. The radioactive releases to surface waters and the surficial environment from the Mayak site are the largest known in the world. However, they are dwarfed by the amounts of liquid wastes injected into the subsurface at Tomsk and Krasnoyarsk since the early 1960s. This paper provides the status of efforts by Pacific Northwest National Laboratory to quantify the regional hydrogeologic context for potential contaminant migration from areas in western Siberia. The West Siberian Basin is the largest platformal basin and region of low relief on earth. Ground water in the West Siberian Basin is contained in a single geologic structure (i.e., a single basin). Hydrogeologic cross sections indicate that freshwater wedges are present in both unconfined and confined aquifers (as well as in Paleozoic rocks) in the highland regions that rim the basin. The authors developed a 13-layer, finite-element computer model of the West Siberian Basin primarily based on GIS integration of data from geologic studies. The top of the hydrologic system was assumed to coincide with a water table derived from smoothed topography and surface-water occurrences; precipitation supplied the water, and the topographic gradient of the water table supplied the driving force for ground-water flow. The general directions of calculated ground-water flow suggest that (1) the major rivers act as discharge areas, with upwelling below the rivers extending down into the basement rocks; and (2) ground-water divides that penetrate the entire thickness of the model are evident between the major rivers. Their results suggest that contaminants entering the confined aquifer system may eventually migrate to the surface, discharging within major rivers, rather than remaining confined for long travel distances within the basin sediments.

  11. Initiation and Impact of Siberian Traps Volcanism

    NASA Astrophysics Data System (ADS)

    Planke, S.; Svensen, H.; Polozov, A. G.; Jerram, D.; Faleide, J. I.

    2011-12-01

    The Siberian Traps Large Igneous Province was formed during the end-Permian, about 251 million years ago. Basaltic melt was injected into the organic and salt rich Tunguska sedimentary basin, forming interconnected sill complexes and associated hydrothermal vent complexes. The initial eruptions took place in a wet environment, documented by tuff layers. The explosive eruptions were followed by effusive magmatism, forming the characteristic volcanic traps. Further away, in the southwest Barents Sea, the earliest Triassic is characterized by rapid basin subsidence and deposition of thick clastic sedimentary sequences. We have conducted field work in Siberia during 2004 to 2010 to study the formation and implications of the Siberian Traps volcanism. The massive magmatism likely triggered the end-Permian mass extinction and pertubated the global carbon cycle. Four key processes link the Siberian Traps Large Igneous Province to the end-Permian carbon cycle perturbation and mass extinction: 1) degassing of subaerially emplaces lava flows, 2) explosive volcanism and tephra eruptions, 3) phreatomagmatic pipes rooted in the evaporates of the Tunguska Basin, and 4) degassing following contact metamorphism around coal, shale, and evaporate lithologies in the Tunguska Basin. Field work in 2010 focused on the nature of explosive volcanism and tephra eruptions. Thick deposits of basaltic tuff and tephra have been reported as widespread in the lower succession of the Siberian Traps, for instance in the Maymecha region (300 meters of basal mafic tuffs), commonly taken as direct evidence for the explosive nature of the initial phase of volcanism. This is puzzling as explosive volcanism is unusual in low viscosity and volatile-poor basaltic systems. As few modern studies have documented the extent and nature of these tuff deposits, especially in the areas outside the ore-rich regions around Norilsk, this may have contributed to their enigmatic status. The field work revealed that

  12. Multiple Partial Siberian Snakes in the AGS

    SciTech Connect

    Takano, J.; Ahrens, L. A.; Bai, M.; Brown, K.; Courant, E. D.; Gardner, C. J.; Glenn, J. W.; Huang, H.; Luccio, A. U.; MacKay, W. W.; Okamura, M.; Roser, T.; Tepikian, S.; Tsoupas, N.; Yip, K.; Zelenski, A.; Zeno, K.; Hattori, T.; Lin, F.

    2007-06-13

    Polarized protons are accelerated up to 24.3 GeV in the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL). To accelerate the beam with preserving the polarization, two different types of helical dipole partial Siberian snake have been installed to the AGS. One is a superconducting magnet (Cold Snake, CSNK), and the other is a normal conducting one (Warm Snake, WSNK). With these snake magnets, the polarization at the AGS extraction achieved 65%. However, the AGS has spin mismatches at the injection and extraction. This description shows calculated results to have better spin matching with using two or three snakes.

  13. Multiple Partial Siberian Snakes in the AGS

    NASA Astrophysics Data System (ADS)

    Takano, J.; Ahrens, L. A.; Bai, M.; Brown, K.; Courant, E. D.; Gardner, C. J.; Glenn, J. W.; Hattori, T.; Huang, H.; Lin, F.; Luccio, A. U.; MacKay, W. W.; Okamura, M.; Roser, T.; Tepikian, S.; Tsoupas, N.; Yip, K.; Zelenski, A.; Zeno, K.

    2007-06-01

    Polarized protons are accelerated up to 24.3 GeV in the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL). To accelerate the beam with preserving the polarization, two different types of helical dipole partial Siberian snake have been installed to the AGS. One is a superconducting magnet (Cold Snake, CSNK), and the other is a normal conducting one (Warm Snake, WSNK). With these snake magnets, the polarization at the AGS extraction achieved 65%. However, the AGS has spin mismatches at the injection and extraction. This description shows calculated results to have better spin matching with using two or three snakes.

  14. Siberian Snake solenoid for the AGS

    SciTech Connect

    Ratner, L. G.

    1991-01-01

    Recent experiments at the Indiana University Cyclotron Facility (IUCF) have demonstrated that Siberian Snakes'' can be used to preserve the polarization of an accelerated polarized beam in a circular accelerator. Retrofitting full snakes into accelerators such as the Alternating Gradient Synchrotron (AGS) at Brookhaven is almost impossible due to space limitations, but a partial snake that can correct depolarization due to imperfection resonances with 1/20 to 1/30 of a full strength snake seems to present a viable option. We describe such a device for the AGS and give the design criteria in terms of simplicity of accelerator operation and level of achievable polarization. 2 refs., 5 figs., 1 tab.

  15. Effect of Gonadectomy on the Androgen-Dependent Behavior of Ganglion Cell-Like Cells in Djungarian Hamsters (Phodopus sungorus).

    PubMed

    Nakahira, Rei; Yoshida, Rumika; Michishita, Masaki; Ohkusu-Tsukada, Kozo; Takahashi, Kimimasa

    2016-02-01

    Ganglion cell-like (GL) cells reside in the dermis of the ventral skin of mature male Djungarian hamsters (Phodopus sugorus) and express androgen receptor (AR). To assess whether GL cells have androgen-dependent behavior, we evaluated the histologic changes of GL cells after gonadectomy. Five male and 5 female hamsters were gonadectomized at the age of 4 wk and necropsied 14 wk later. The number, distribution, and proliferative activity of GL cells in the thoracoabdominal and dorsal skins were evaluated histologically and compared with those of corresponding intact animals. GL cells were more numerous, were distributed throughout the skin more widely, and had higher proliferative activity in the intact male hamsters than in their gonadectomized counterparts. Similar trends regarding these 3 parameters were seen in ovariectomized compared with intact female hamsters and between intact male and intact female hamsters. These results suggest that the GL cells of Djungarian hamsters demonstrate sex-associated differences in their distribution and proliferative activity and that androgen may be involved in the development of these cells.

  16. Short-day response in Djungarian hamsters of different circadian phenotypes.

    PubMed

    Schöttner, Konrad; Schmidt, Maren; Hering, Anke; Schatz, Juliane; Weinert, Dietmar

    2012-05-01

    In Djungarian hamsters (Phodopus sungorus) bred at the authors' institute, a certain number of animals show activity patterns incompatible with proper entrainment of their endogenous circadian pacemaker to the environmental light-dark (LD) cycle. Even though the activity-offset in these animals is stably coupled to "light-on," activity-onset is increasingly delayed, leading to a compression of the activity time (α). If α falls below a critical value, the circadian rhythm in these so called delayed activity-onset (DAO) hamsters starts to free-run and finally breaks down. Animals then show an arrhythmic activity pattern (AR hamsters). Previous studies revealed the mechanisms of photic entrainment have deteriorated (DAO) or the suprachiasmatic nucleus (SCN) does not generate a rhythmic signal (AR). The aim of the present study was to investigate the consequences that these deteriorations have upon photoperiodic time measurement. Animals were bred and kept under standardized housing conditions with food and water ad libitum and a 14L/10D (long day, LD) regimen. Locomotor activity was recorded continuously using passive infrared motion detectors. Body mass, testes size, and fur coloration were measured weekly or biweekly to further quantify the photoperiodic reaction. In a first experiment, adult male wild-type (WT), DAO, and AR hamsters were transferred initially to a 16L/8D cycle. After 3-4 wks, the light period was shortened symmetrically by 8 h. After 14 wks, none of the DAO and AR hamsters, and only 1 of 8 WT hamsters showed short-day (SD) traits. Therefore, in a second experiment, hamsters were transferred to SD conditions (8L/16D cycle) for 8 wks directly from standard LD conditions. In 6 of 7 WT hamsters, activity time expanded, body mass and testes size decreased, and fur coloration changed from summer to winter pelage. In contrast, none of the DAO and AR hamsters displayed an SD response. In a third experiment, DAO and AR hamsters were kept in constant

  17. Autoradiographic localization of tritiated dihydrotestosterone in the flank organ of the albino hamster

    SciTech Connect

    Lucky, A.W.; Eisenfeld, A.J.; Visintin, I.

    1985-02-01

    In the hamster flank organ, the growth of hair and growth of sebaceous glands are androgen-dependent functions. Although dihydrotestosterone (DHT) is known to be a potent stimulator of flank organ growth, there is no information about localization of DHT receptor sites in this organ. The purpose of this study was to use steroid autoradiography to localize DHT receptors in the hamster flank organ. Because steroid hormones are functional when translocated to nuclear receptors, nuclear localization by autoradiography defines receptor sites. In order to be able to visualize autoradiographic grains from radiolabeled androgens around hair follicles, albino hamsters were studied to avoid confusion between the grains and pigment granules which are abundant in the more common Golden Syrian hamster. Mature male hamsters castrated 24 hours earlier were given tritium-labeled dihydrotestosterone ( (/sup 3/H)DHT). Using the technique of thaw-mount steroid autoradiography, 4-micron unfixed frozen sections were mounted in the dark onto emulsion-coated glass slides and allowed to develop for 4-6 months. (/sup 3/H)DHT was found to be concentrated over sebocyte nuclei. The label was present peripherally as well as in differentiating sebocytes. There was no nuclear localization of (/sup 3/H)DHT in animals pretreated with excessive quantities of unlabeled DHT. Steroid metabolites of (/sup 3/H) DHT were assessed by thin-layer chromatography in paired tissue samples. Most of the label remained with DHT. Uptake was inhibited in the flank organ of hamsters pretreated with unlabeled DHT.

  18. Aneuploidy in spermatozoa detected by FISH. Comparison with sperm chromosome data obtained via hamster system

    SciTech Connect

    Estop, A.M.; Van Kirk, V.; Cieply, K.

    1994-09-01

    Fluorescence in-situ hybridization (FISH) with two-color and cocktail DNA probes was used to assess the rates of aneuploidy for the X,Y and 18 chromosomes in 3 male donors. (Experiment 1). These individuals had previously been studied with the hamster system and published. Experiment 2 was designed in order to compare aneuploidy rates for chromosome 18 in donor 2 in conjunction with chromosome 6 and 12 as an internal control. (1) Aneuploidy for the sex chromosomes in the hamster system was 0.5 for Donor 1 and 0.7 (3) which was very similar to 0.49 (1) and 0.41 (3) found in this experiment. However, Donor 2 showed a lower rate of sex non-disjunction with this system: 0.18 vs. 0.7 with the hamster system. (2) Diploidy rates are in the same ranges in experiments 1 and 2. (3) If autosome aneuploidy rates are extrapolated to 22 chromosomes, the following values are found: Donor 1:2.42 (vs. 2.0 in the hamster system); donor 3:2.2 (vs. 1.34 with the hamster system) and donor 2:1.32 which is lower than 4.32 found with the hamster system. More data needs to be collected on the use of FISH for this study of aneuploides in sperm cells and attention needs to be paid to the different types of probes used for validation of results.

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

    SciTech Connect

    Persson, S.A.; Ahlberg, M.; Berghem, L.; Koenberg, E.N.; Nordberg, G.F.; Bergman, F.

    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, oil 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.

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

    PubMed Central

    Persson, S A; Ahlberg, M; Berghem, L; Könberg, E; Nordberg, G F; Bergman, F

    1988-01-01

    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 (Fe2O3). 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, oil fly ash, or Fe2O3 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. Images FIGURE 3. FIGURE 4. PMID:3383816

  1. Siberian Platform: Geology and Natural Bitumen Resources

    USGS Publications Warehouse

    Meyer, Richard F.; Freeman, P.A.

    2006-01-01

    Summary: The Siberian platform is located between the Yenisey River on the west and the Lena River on the south and east. The Siberian platform is vast in size and inhospitable in its climate. This report is concerned principally with the setting, formation, and potential volumes of natural bitumen. In this report the volumes of maltha and asphalt referred to in the Russian literature are combined to represent natural bitumen. The generation of hydrocarbons and formation of hydrocarbon accumulations are discussed. The sedimentary basins of the Platform are described in terms of the Klemme basin classification system and the conditions controlling formation of natural bitumen. Estimates of in-place bitumen resources are reviewed and evaluated. If the bitumen volume estimate is confined to parts of identified deposits where field observations have verified rock and bitumen grades values, the bitumen resource amounts to about 62 billion barrels of oil in-place. However, estimates of an order of magnitude larger can be obtained if additional speculative and unverified rock volumes and grade measures are included.

  2. Effects of short photoperiod on energy intake, thermogenesis, and reproduction in desert hamsters (Phodopus roborovskii).

    PubMed

    Zhang, Xueying; Zhao, Zhijun; Vasilieva, Nina; Khrushchova, Anastasia; Wang, Dehua

    2015-03-01

    Desert hamsters (Phodopus roborovskii) are the least known species in the genus Phodopus with respect to ecology and physiology, and deserve scientific attention, particularly because of their small body size. Here, the responses of energy metabolism and reproductive function to short photoperiods in desert hamsters were investigated. Male and female desert hamsters were acclimated to either long day (LD) (L:D 16:8 h) or short day (SD) photoperiods (L:D 8:16 h) for three months, and then the females were transferred back to an LD photoperiod for a further five months, while at the end of the SD acclimation the males were killed and measurements were taken for serum leptin as well as molecular markers for thermogenesis. We found that like the other two species from the genus Phodopus, the desert hamsters under SD decreased body mass, increased adaptive thermogenesis as indicated by elevated mitochondrial protein content and uncoupling protein-1 content in brown adipose tissue, and suppressed reproduction compared to those under LD. However, different from the other two species, desert hamsters did not show any differences in energy intake or serum leptin concentration between LD and SD. These data suggest that different species from the same genus respond in different ways to the environmental signals, and the desert adapted species are not as sensitive to change in photoperiod as the other two species.

  3. Evaluation of amitrole (aminotriazole) for potential carcinogenicity in orally dosed rats, mice, and golden hamsters

    SciTech Connect

    Steinhoff, D.; Weber, H.; Mohr, U.; Boehme, K.

    1983-06-30

    Amitrole was evaluated for carcinogenic potential in lifespan studies on Wistar rats, NMRI mice, and golden hamsters. At the start of the studies the animals were 6 weeks old. Amitrole was administered, mixed with pulverized chow, at dietary concentrations of 0, 1, 10, and 100 micrograms/g (ppm). Each treated group and control group consisted of 75 male and 75 female rats and mice and of 76 male and 76 female golden hamsters. Additional animals were used to evaluate the functional state of the thyroid. Somewhat lower body weights, slightly reduced survival times, and transient effects on thyroid function were observed in golden hamsters at 100 ppm. In mice, a slight increase in pituitary gland hyperemias was seen at 100 ppm; also an effect on thyroid function usually occurred at the same concentration. In rats, a very large number of cystic dilatations of follicles in the thyroid at 100 ppm and a dose-unrelated increase in hemorrhages and hyperemias in the pituitary gland were indicative of an effect of amitrole on these organs. The strongest effect of amitrole on thyroid function, as compared to golden hamsters and mice, was seen in rats at 100 ppm. At this concentration a highly increased number of thyroid and pituitary gland tumors was observed in rats. In golden hamsters and mice, no tumor induction was seen.

  4. Evaluation of amitrole (aminotriazole) for potential carcinogenicity in orally dosed rats, mice, and golden hamsters.

    PubMed

    Steinhoff, D; Weber, H; Mohr, U; Boehme, K

    1983-06-30

    Amitrole was evaluated for carcinogenic potential in lifespan studies on Wistar rats, NMRI mice, and golden hamsters. At the start of the studies the animals were 6 weeks old. Amitrole was administered, mixed with pulverized chow, at dietary concentrations of 0, 1, 10, and 100 micrograms/g (ppm). Each treated group and control group consisted of 75 male and 75 female rats and mice and of 76 male and 76 female golden hamsters. Additional animals were used to evaluate the functional state of the thyroid. Somewhat lower body weights, slightly reduced survival times, and transient effects on thyroid function were observed in golden hamsters at 100 ppm. In mice, a slight increase in pituitary gland hyperemias was seen at 100 ppm; also an effect on thyroid function usually occurred at the same concentration. In rats, a very large number of cystic dilatations of follicles in the thyroid at 100 ppm and a dose-unrelated increase in hemorrhages and hyperemias in the pituitary gland were indicative of an effect of amitrole on these organs. The strongest effect of amitrole on thyroid function, as compared to golden hamsters and mice, was seen in rats at 100 ppm. At this concentration a highly increased number of thyroid and pituitary gland tumors was observed in rats. In golden hamsters and mice, no tumor induction was seen.

  5. Hibernation patterns of Turkish hamsters: influence of sex and ambient temperature.

    PubMed

    Batavia, Mariska; Nguyen, George; Harman, Kristine; Zucker, Irving

    2013-02-01

    Turkish hamsters (Mesocricetus brandti) are a model organism for studies of hibernation, yet a detailed account of their torpor characteristics has not been undertaken. This study employed continuous telemetric monitoring of body temperature (T(b)) in hibernating male and female Turkish hamsters at ambient temperatures (T(a)s) of 5 and 13 °C to precisely characterize torpor bout depth, duration, and frequency, as well as rates of entry into and arousal from torpor. Hamsters generated brief intervals of short (<12 h), shallow test bouts (T(b) > 20 °C), followed by deep torpor bouts lasting 4-6 days at T(a) = 5 °C and 2-3 days at T(a) = 13 °C. Females at T(a) = 5 °C had longer bouts than males, but maintained higher torpor T(b); there were no sex differences at T(a) = 13 °C. Neither body mass loss nor food intake differed between the two T(a)s. Hamsters entered torpor primarily during the scotophase (subjective night), but timing of arousals was highly variable. Hamsters at both T (a)s generated short, shallow torpor bouts between deep bouts, suggesting that this species may be capable of both hibernation and daily torpor.

  6. Induction of renal and hepatic mixed function oxidases in the hamster and guinea pig.

    PubMed

    Smith, J H; Rush, G F; Hook, J B

    1986-02-01

    A marked species difference exists in the induction of renal and hepatic mixed function oxidase (MFO) activity between rats and rabbits. However, little is known about MFO induction in these organs from other laboratory animals. Male Golden Syrian hamsters and male Hartley guinea pigs were administered phenobarbital (PB) or beta-napthoflavone (BNF) at 70 and 40 mg/kg, respectively, as daily i.p. injections for 4 days. Polybrominated biphenyl (PBB) (Firemaster BP-6) was given as a single i.p. injection (50 mg/kg). Hamster hepatic microsomal ethoxyresorufin-O-deethylase (EROD) and benzphetamine-N-demethylase (BPND) were selectively induced by BNF and PB, respectively. PBB administration induced both hamster hepatic EROD and BPND. In contrast, hepatic microsomal MFO activity from the guinea pig was inducible by PB, PBB and BNF. Renal microsomal MFO activity in both species was inducible by BNF and PBB as arylhydrocarbon hydroxylase and EROD were induced approximately 10-fold. On the other hand, hamster BPND was induced by PB whereas guinea pig MFO activity was unaffected. Total renal cytochrome P-450 content was not affected by any of these inducers in either species. These data demonstrate selective patterns of induction in both hamster and guinea pig liver and kidney suggesting the involvement of multiple forms of cytochrome P-450.

  7. Artichoke extract lowered plasma cholesterol and increased fecal bile acids in Golden Syrian hamsters.

    PubMed

    Qiang, Zhiyi; Lee, Sun-Ok; Ye, Zhong; Wu, Xianai; Hendrich, Suzanne

    2012-07-01

    A study was conducted in hamsters to determine if artichoke leaf extract (ALE) could lower plasma total and non-HDL cholesterol by increasing fecal excretion of neutral bile acids and sterols. Sixty-four Golden Syrian hamsters (8 week old) were fed control diet or a similar diet containing ALE (4.5 g/kg diet) for 6 weeks. No significant changes for total cholesterol, HDL, non-HDL cholesterol triglycerides or fecal neutral sterols and bile acids were found after 21 days for ALE-fed animals compared with controls. But after 42 days, ALE-fed male hamsters had significantly lower total cholesterol (15%), non-HDL cholesterol (30%) and triglycerides (22%) and female hamsters fed ALE showed reductions of 15% for total cholesterol, 29% for non-HDL cholesterol and 29% for triglycerides compared with controls. Total neutral sterol and bile acids concentrations increased significantly by 50% and 53% in fecal samples of ALE fed males, and 82.4% and 25% in ALE fed females compared with controls. The ALE lowered hamster plasma cholesterol levels by a mechanism involving the greater excretion of fecal bile acids and neutral sterols after feeding for 42 days. Copyright © 2011 John Wiley & Sons, Ltd.

  8. In-vivo monitoring of development of cholangiocarcinoma induced with C. sinensis and N-nitrosodimethylamine in Syrian golen hamsters using ultrasonography and magnetic resonance imaging: a preliminary study.

    PubMed

    Woo, Hyunsik; Han, Joon Koo; Kim, Jung Hoon; Hong, Sung-Tae; Uddin, Md Hafiz; Jang, Ja-June

    2017-04-01

    The purpose of this study is to evaluate high-resolution ultrasound and magnetic resonance imaging (MRI) in monitoring of cholangiocarcinoma in the hamsters with C. sinensis infection and N-nitrosodimethylamine (NDMA). Twenty-four male Syrian golden hamsters of were divided into four groups composed of five hamsters as control, five hamsters receiving 30 metacercariae of C. sinensis per each hamster, five hamsters receiving NDMA in drinking water, and nine hamsters receiving both metacercariae and NDMA. Ultrasound was performed every other week from baseline to the 12th week of infection. MRI and histopathologic examination was done from the 4th week to 12th week. Cholangiocarcinomas appeared as early as the 6th week of infection. There were 12 cholangiocarcinomas, nine and ten of which were demonstrated by ultrasound and MRI, respectively. Ultrasound and MRI findings of cholangiocarcinomas in the hamsters were similar to those of the mass-forming intrahepatic cholangiocarcinomas in humans. Ultrasound and MRI also showed other findings of disease progression such as periductal increased echogenicity or signal intensity, ductal dilatation, complicated cysts, and sludges in the gallbladder. High-resolution ultrasound and MRI can monitor and detect the occurrence of cholangiocarcinoma in the hamsters non-invasively. • High-resolution ultrasound and MRI can monitor occurrence of cholangiocarcinoma in the hamsters. • Cholangiocarcinomas were detected as early as the 6th week after C. sinensis infection. • Axial T2-weighted MRI demonstrated cholangiocarcinomas and various inflammatory findings in the hamsters.

  9. ACCELERATION OF POLARIZED BEAMS USING MULTIPLE STRONG PARTIAL SIBERIAN SNAKES.

    SciTech Connect

    ROSER,T.; AHRENS,L.; BAI,M.; COURANT,E.; GLENN,J.W.; GUPTA,R.C.; HUANG,H.; LUCCIO,A.U.; MACKAY,W.W.; TSOUPAS,N.; WILLEN,E.; OKAMURA,M.; TAKANO,J.

    2004-10-10

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20-30% partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.

  10. ACCELERATION OF POLARIZED BEAMS USING MULTIPLE STRONG PARTIAL SIBERIAN SNAKES.

    SciTech Connect

    ROSER,T.AHRENS,L.BAI,M.ET AL.

    2004-07-05

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20-30% partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.

  11. Acceleration of Polarized Beams Using Multiple Strong Partial Siberian Snakes

    NASA Astrophysics Data System (ADS)

    Roser, T.; Ahrens, L. A.; Bai, M.; Courant, E. D.; Glenn, J. W.; Gupta, R. C.; Huang, H.; Luccio, A. U.; Mackay, W. W.; Tsoupas, N.; Willen, E.; Okamura, M.; Takano, J.

    2005-08-01

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization, but full Siberian snakes cause intolerably large orbit excursions. Using a 20 - 30 % partial Siberian snake, both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical super-conducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.

  12. 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…

  13. 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…

  14. Lifetime carcinogenesis studies of amosite asbestos (Case No. 121-72-73-5) in Syrian golden hamsters (feed studies). Technical report series

    SciTech Connect

    Not Available

    1983-11-01

    Carcinogenesis studies of amosite asbestos were conducted by administering diets containing 1% of the asbestos in pellets from the conception of the mothers through the lifetime of male and female Syrian golden hamsters. Control groups consisted of 127 male and 126 female hamsters and the amosite asbestos group consisted of 252 male and 254 female hamsters. No adverse effect on body-weight gain or survival was observed from treatment with amosite asbestos. Neither of the amosite asbestos groups showed increased neoplasia in any organ or tissue compared to the control groups. Under the conditions of these studies, the ingestion of amosite asbestos at a level of 1% in the diet for their lifetime was not toxic and did not cause a carcinogenic response in male and female Syrian golden hamsters.

  15. Klinefelter syndrome (39 XXY) in an adult Siberian tiger (Panthera tigris altaica).

    PubMed

    Suedmeyer, Wm Kirk; Houck, Marlys L; Kreeger, John

    2003-03-01

    Fibroblast cultures of a skin biopsy from an adult intact male Siberian tiger (Panthera tigris altaica) revealed an abnormal standard and G-banded karyotype diploid chromosome number of 2n = 39 XXY due to an extra sex chromosome as opposed to the expected 2n = 38 XY. The tiger was euthanatized 1 yr later due to acute multifocal intervertebral disc disease. Histopathology of the reproductive tract demonstrated a paucity of seminiferous tubules and these were devoid of spermatagonia. An increase in fibrous connective tissue was noted in sections of the prostate and epididymis, and expansion of the fibrous interstitium was observed in the testes.

  16. Pentalogy of Fallot in a captive Siberian tiger (Panthera tigris altaica).

    PubMed

    Scaglione, Frine E; Tursi, Massimiliano; Chiappino, Laura; Schröder, Cathrin; Triberti, Orfeo; Bollo, Enrico

    2012-12-01

    A 2-yr-old male Siberian Tiger (Panthera tigris altaica) died during a fight with a conspecific. At necropsy, significant abnormalities included severe cardiomegaly with cardiac malformations consisting of a large atrial septal defect, a membranous ventricular septal defect, overriding aorta, and stenosis of the pulmonary valve with secondary concentric hypertrophy of the right ventricle. Endocardiosis of the mitral valve was also noted. To the authors' knowledge, this is the first report of a pentalogy of Fallot in a large felid that resulted in sudden death.

  17. Novel function of lipids as a pheromone from the Harderian gland of golden hamster

    PubMed Central

    Seyama, Yousuke; Uchijima, Yasunobu

    2007-01-01

    Sexual diversity of ADG in Harderian gland of golden hamster was demonstrated on TLC. Female ADG contained iso- and anteiso-branched acyl and alkyl components, but male ADG contained only straight chain ones, which suggested the hormonal control of the expression of acyl-CoA dehydrogenases in the catabolism of BCAA. Acyl-CoA dehydrogenases were not expressed in the absence of testosterone, and then isovaleryl-CoA, 2-methylbutyryl-CoA, and isobutyryl-CoA accumulated, and acted as primers for the synthesis of iso- and anteiso-branched fatty acids. The incorporation of [U-14C] leucine into lipids was monitored by TLC. The cholesterol fraction was labeled in males but not in female, which means that cholesterol was not produced from BCAA in female gland due to the lack of expression of acyl-CoA dehydrogenases. We monitored the behavior of male hamsters toward female gland lipids, and found slightly greater attractiveness in female ones than that in male ones although the difference was not significant. Considering the lifestyle of golden hamster in nature, we propose a hypothesis that the lipids from the Harderian gland of golden hamster serve as a pheromone to declare their territory and to seek the mate with good congeniality. PMID:24019586

  18. Siberian snakes for the Fermilab Main Injector

    SciTech Connect

    Anferov, V.A.; Baiod, R.; Courant, E.D.

    1993-04-01

    Appropriate Siberian snakes were designed to maintain the proton beam polarization during acceleration in the Fermilab Main Injector from 8 to 150 GeV. Various snake designs were investigated to find one fitting into the 14 m straight section spaces with the required spin rotation axis and the minimum orbit excursion. The authors studied both cold and warm discrete magnet snakes as well as warm snakes with helical magnets. For the warm discrete magnet snake, obtaining small orbit excursions required a nearly longitudinal snake axis, while axes near {+-}45{degrees} are needed when using two snakes in a ring. The authors found acceptable snakes either by using superconducting magnets or by using warm magnets with a helical dipole field.

  19. New geological data of New Siberian Archipelago

    NASA Astrophysics Data System (ADS)

    Sobolev, Nikolay; Petrov, Evgeniy

    2014-05-01

    The area of New Siberian Archipelago (NSA) encompasses different tectonic blocks is a clue for reconstruction of geological structure and geodynamic evolution of East Arctic. According to palaeomagnetic study two parts of the archipelago - Bennett and Anjou Islands formed a single continental block at least from the Early Palaeozoic. Isotope dating of De Long Islands igneous and sedimentary rocks suggests Neoproterozoic (Baikalian) age of its basement. The De Long platform sedimentary cover may be subdivided into two complexes: (1) intermediate of PZ-J variously deformed and metamorphosed rocks and (2) K-KZ of weakly lithified sediments. The former complex comprises the Cambrian riftogenic volcanic-clastic member which overlain by Cambrian-Ordovician turbiditic sequence, deposited on a continental margin. This Lower Palaeozoic complex is unconformably overlain by Early Cretaceous (K-Ar age of c.120 Ma) basalts with HALIP petrochemical affinities. In Anjou Islands the intermediate sedimentary complex encompasses the lower Ordovician -Lower Carboniferous sequence of shallow-marine limestone and subordinate dolomite, mudstone and sandstone that bear fossils characteristic of the Siberian biogeographic province. The upper Mid Carboniferous - Jurassic part is dominated by shallow-marine clastic sediments, mainly clays. The K-KZ complex rests upon the lower one with angular unconformity and consists mainly of coal-bearing clastic sediments with rhyolite lavas and tuffs in the bottom (117-110 Ma by K-Ar) while the complexe's upper part contains intraplate alkalic basalt and Neogene-Quaternary limburgite. The De-Long-Anjou block's features of geology and evolution resemble those of Wrangel Island located some 1000 km eastward. The Laptev Sea shelf outcrops in intrashelf rises (Belkovsky and Stolbovoy Islands) where its geology and structure may be observed directly. On Belkovsky Island non-dislocated Oligocene-Miocene sedimentary cover of littoral-marine coal

  20. Field of a helical Siberian Snake

    SciTech Connect

    Luccio, A.

    1995-02-01

    To preserve the spin polarization of a beam of high energy protons in a circular accelerator, magnets with periodic magnetic field, called Siberian Snakes are being used. Recently, it was proposed to build Siberian Snakes with superconducting helical dipoles. In a helical, or twisted dipole, the magnetic field is perpendicular to the axis of the helix and rotates around it as one proceeds along the magnet. In an engineering study of a 4 Tesla helical snake, the coil geometry is derived, by twisting, from the geometry of a cosine superconducting dipole. While waiting for magnetic measurement data on such a prototype, an analytical expression for the field of the helice is important, to calculate the particle trajectories and the spin precession in the helix. This model will also allow to determine the optical characteristics of the snake, as an insertion in the lattice of the accelerator. In particular, one can calculate the integrated multipoles through the magnet and the equivalent transfer matrix. An expression for the field in the helix body, i.e., excluding the fringe field was given in a classical paper. An alternate expression can be found by elaborating on the treatment of the field of a transverse wiggler obtained under the rather general conditions that the variables are separable. This expression exactly satisfies Maxwell`s div and curl equations for a stationary field, {del} {center_dot} B = 0, {del} x B = 0. This approach is useful in that it will allow one to use much of the work already done on the problem of inserting wigglers and undulators in the lattice of a circular accelerator.

  1. Ascarid infestation in captive Siberian tigers in China.

    PubMed

    Peng, Zhiwei; Liu, Shijie; Hou, Zhijun; Xing, Mingwei

    2016-08-15

    The Siberian tiger is endangered and is listed by the International Union for the Conservation of Nature; the captive environment is utilized to maintain Siberian tiger numbers. Little information regarding the prevalence of parasites in Siberian tigers is available. A total of 277 fecal samples of Siberian tigers were analyzed in this study. The microscopic analysis indicated the presence of ascarid eggs of Toxascaris leonina and Toxocara cati. The ascarid infection rate was 67.5% in Siberian tigers. The internal transcribed spacer-1 (ITS-1) phylogenetic analysis indicated that T. leonina belonged to Toxascaris and that Toxo. cati belonged to Toxocara. The infestation rate and intensity of T. leonina were higher than those of Toxo. cati. One-way analysis of variance showed that the presence of T. leonina was significantly associated with age (P<0.05). Temperature changes also influenced T. leonina and Toxo. cati infestation, and a rise in temperature caused an increase in the number of T. leonina and Toxo. cati eggs. This study provides a better understanding of ascarid infestation among the captive Siberian tigers and is helpful for the prevention of the spread of infectious parasitic diseases among other tigers in the zoo. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Reconstructing genetic history of Siberian and Northeastern European populations

    PubMed Central

    Wong, Emily H.M.; Khrunin, Andrey; Nichols, Larissa; Pushkarev, Dmitry; Khokhrin, Denis; Verbenko, Dmitry; Evgrafov, Oleg; Knowles, James; Novembre, John; Limborska, Svetlana; Valouev, Anton

    2017-01-01

    Siberia and Northwestern Russia are home to over 40 culturally and linguistically diverse indigenous ethnic groups, yet genetic variation and histories of peoples from this region are largely uncharacterized. We present deep whole-genome sequencing data (∼38×) from 28 individuals belonging to 14 distinct indigenous populations from that region. We combined these data sets with additional 32 modern-day and 46 ancient human genomes to reconstruct genetic histories of several indigenous Northern Eurasian populations. We found that Siberian and East Asian populations shared 38% of their ancestry with a 45,000-yr-old Ust’-Ishim individual who was previously believed to have no modern-day descendants. Western Siberians trace 57% of their ancestry to ancient North Eurasians, represented by the 24,000-yr-old Siberian Mal'ta boy MA-1. Eastern Siberian populations formed a distinct sublineage that separated from other East Asian populations ∼10,000 yr ago. In addition, we uncovered admixtures between Siberians and Eastern European hunter-gatherers from Samara, Karelia, Hungary, and Sweden (from 8000–6600 yr ago); Yamnaya people (5300–4700 yr ago); and modern-day Northeastern Europeans. Our results provide new insights into genetic histories of Siberian and Northeastern European populations and evidence of ancient gene flow from Siberia into Europe. PMID:27965293

  3. Plasma fatty acid profiles of Canadian Inuit and Siberian Ganasan.

    PubMed

    Rode, A; Shephard, R J; Vloshinsky, P E; Kuksis, A

    1995-01-01

    Cross-sectional data from 86 male and 59 female coastal Inuit of Igloolik (69 degrees 40'N, 81 degrees W) showed a steep age-related increase in the percentage of plasma n-3 fatty acids, with parallel trends in 20:5 and 22:6 but not 18:3 n-3 fatty acid concentrations. Omega-7 + 9 (p < .001) and omega-9 fatty acid concentrations (P < .001 in M, .008 in F) also decreased with age. A tundra-based Siberian indigenous population (30 male and 11 female nGanasan) had similar percentages of n-3 and n-6 fatty acids to the young Inuit, with little age-related change in either measure. Correlation matrices for the Inuit men showed quite strong negative associations of n-3 fatty acid percentages with total triglycerides (r = .34, p < .001) and phosphatidylcholine/free cholesterol ratio (r = -.36, p < .001). In the Inuit women, n-3 percentages were strongly related to phosphatidylcholine/free cholesterol ratio (r = -.60, p < .001), but not to triglyceride readings. The phosphatidylcholine/free cholesterol ratio was also correlated with n-6 percentages (r = -.55, p < .001). In the nGanasan men, triglyceride levels were correlated with n-6 (r = -.35, p < .050), but the size of the female sample was insufficient to establish useful correlations. The present data suggest that as the younger coastal Inuit are abandoning their traditional country foods, plasma levels of n-3 fall. Reasons why n-3 fatty acid levels are negatively related to the plasma phosphatidyl choline/free cholesterol ratio merit further investigation.

  4. Healing acceleration in hamsters of oral mucositis induced by 5-fluorouracil with topical Calendula officinalis.

    PubMed

    Tanideh, Nader; Tavakoli, Parisa; Saghiri, Mohammad Ali; Garcia-Godoy, Franklin; Amanat, Dariush; Tadbir, Azadeh Andisheh; Samani, Soleiman Mohammadi; Tamadon, Amin

    2013-03-01

    This study assessed the potential of topical Calendula officinalis extract on the healing of oral mucositis induced by 5-fluorouracil (5-FU) in hamsters. Oral mucositis was induced in 60 male hamsters by 5-FU (60 mg/kg) on days 0, 5, and 10 of the study. The cheek pouch was scratched with a sterile needle on days 1 and 2. On days 12-17, 5% and 10% C. officinalis gel and gel base groups were treated and then compared with a control group. Macroscopic and microscopic scores and weights were evaluated. Microscopic and macroscopic scores of mucositis were lower in the 5% and 10% C. officinalis gel groups than in the gel base and control groups (P < .05). Weight gain was noted in the treatment groups compared with the gel base and control groups (P < .05). Calendula officinalis extract accelerated the healing of oral mucositis in hamsters. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Running-wheel activity and body composition in golden hamsters (Mesocricetus auratus).

    PubMed

    Gattermann, Rolf; Weinandy, René; Fritzsche, Peter

    2004-09-15

    Running wheels are frequently used in behavioural and physiological experiments. The function of wheel-running activity in laboratory animals is controversial. In the present long-term study, the influence of this activity was evaluated in male golden hamsters over a period of 52 weeks. Four months after the start of the experiment, hamsters with access to running wheels were significantly heavier than those without these wheels. In addition, food consumption nearly doubled. The absolute values of fat-free mass (FFM), total body water (TBW) and crude fat mass (CFM) increased. However, in contrast to these absolute differences, the relative values were never different and general body composition was therefore unaffected by running-wheel activity. Different organ masses were established for absolute values of kidneys, testes and epididymis; possible effects on reproduction are discussed. The present data indicating improved physical condition leads to the assumption that a running wheel is a useful enrichment, enhancing animal welfare in the golden hamster.

  6. 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.

  7. Trypanosoma cruzi: characterization of reinfection and search for tissue tropism in hamsters (Mesocricetus auratus).

    PubMed

    Cabrine-Santos, M; Lages Silva, E; Chapadeiro, E; Ramírez, L E

    2001-11-01

    Tissue tropism, the role of reinfection in the development of Chagas' disease, and the selection of subpopulations of Trypanosoma cruzi were evaluated in hamsters inoculated with the VIC strain of T. cruzi. Adult allogeneic male hamsters were inoculated once or reinoculated by the intraperitoneal route up to four times with 2000 blood trypomastigotes. Animals were studied by blood culture, histopathology, immunohistochemistry, and molecular techniques (PCR and low-stringency single specific primer-PCR). Homogeneity of the T. cruzi population observed in different tissues suggests that selective tropism of the VIC strain extends only to various muscle tissues in hamsters and that reinfection is not a factor in the development of the inflammatory processes, although it may aggravate it, possibly due to an increase in tissue parasitism, which might induce autoimmune mechanisms. Reinfection did not induce selection of subpopulations in the tissue or in the blood.

  8. Anabolic-androgenic steroid exposure during adolescence and aggressive behavior in golden hamsters.

    PubMed

    Melloni, R H; Connor, D F; Hang, P T; Harrison, R J; Ferris, C F

    1997-03-01

    Anabolic androgenic steroid (AAS) abuse by adolescents represents a significant health care risk due to the potential for long-term negative physical and psychological sequelae, including increased aggressive behavior. The current experiments examined the effects of AAS use in young male adolescent hamsters (Mesocricetus auratus) and their consequences on aggressive behavior. It was hypothesized that AAS administration during adolescence predisposes hamsters to heightened levels of aggressive behavior (i.e., offensive aggression). To test this hypothesis adolescent male hamsters were administered high doses of synthetic AAS to mimic a 'heavy use' self-administration regimen used by athletes. Immediately following the exposure to AAS hamsters were tested for aggressive behavior using a resident-intruder model. Animals treated with high doses of AAS during their adolescent development showed heightened measures of offensive aggression i.e., decreased latency to bite and increased total number of attacks and bites) during the test period, while measures of total activity (total contact time) between the animals remained unchanged. AAS-treated males did not differ in body weight from controls, suggesting that the increased aggression was not due to increased body mass. The results of this study show that exposure to AAS during adolescence facilitates aggressive response patterns, but does not alter body weight.

  9. Effect of age on respiratory carcinogenesis with diethyl-nitrosamine (DEN) in hamsters

    SciTech Connect

    Stinson, S.F.; Saffiotti, U.

    1986-03-01

    Groups of male and female Syrian golden hamsters were given 12 weekly s.c. injections of 10 mg/kg DEN beginning at 1 day (85 animals) or 8 weeks (70 animals) of age, and were held for lifetime observation. In hamsters receiving DEN from birth, the first respiratory tumors were observed at 15 experimental weeks; all animals were dead by 66 weeks with a 99% respiratory tumor incidence. Of these hamster, 87% developed carcinomas or adenomas in the nasal cavities, 75% papillomas of the trachea, larynx or extrapulmonary bronchi and 7% adenomas or adenocarcinomas of the peripheral lung. Hamsters given DEN from 8 weeks of age first showed respiratory tumors after 25 weeks with a 96% incidence by 62 weeks when all had died. Of these hamsters, 24% developed carcinomas or adenomas in the nasal cavities, 91% papillomas of the trachea, larynx or bronchi, and 9% adenomas or adenocarcinomas of the peripheral lung. In comparison, the nasal tumors in the first group were more anaplastic and invaded the brain more frequently than in the second. These results indicate that the nasal mucosa of newborns is more sensitive to carcinogenesis with DEN than is that of adults, while there appears to be little age-related susceptibility of the epithelium of the airways or lung. A serial sacrifice experiment is currently under way to study the cells of origin of the various tumors using immuno-histochemical and electron microscopic techniques.

  10. 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.

  11. Improvement of oxidative stress and immunity by melatonin: an age dependent study in golden hamster.

    PubMed

    Vishwas, Dipanshu Kumar; Mukherjee, Arun; Haldar, Chandana; Dash, Debabrata; Nayak, Manasa K

    2013-02-01

    Reactive oxygen species (ROS) have been proposed to play an important role in balancing the pro- and antioxidant homeostasis during aging. Melatonin has been suggested as an effective free radical scavenger that might have a role during the process of aging. We observed, that melatonin administration (25 μg/100 g body weight for 30 days) significantly augments the activity of anti-oxidative enzymes like superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) in the plasma, spleen and bone marrow (BM) of young (6 weeks), adult (30 weeks) and old aged (2.5 years) male golden hamster, Mesocricetus auratus. A sharp decline in generation of ROS was observed in peripheral blood mononuclear cells (PBMC) and splenocytes upon melatonin administration in different age group of hamsters. Reduction in the level of thiobarbituric acid-reactive substances (TBARS) and total nitrite and nitrate concentration as metabolites and indicators of nitric oxide (NO) in plasma, spleen and BM were observed along with night time (22:00 h) melatonin concentration in different age group of hamsters after administration of melatonin and compared to the control group (treated with 0.9% saline). General immune parameters like proliferation of splenocytes, PBMC and colony forming ability of GM-CFU were observed following melatonin treatment in different age group, although it was low only in aged hamsters compared to the young and adult. Our data indicates that the age related increase of oxidative load and simultaneously augments the general immunity in aged hamsters.

  12. Protective effects of aspirin from cardiac hypertrophy and oxidative stress in cardiomyopathic hamsters.

    PubMed

    Wu, Rong; Yin, David; Sadekova, Nataliya; Deschepper, Christian F; de Champlain, Jacques; Girouard, Helene

    2012-01-01

    To evaluate the capacity of chronic ASA therapy to prevent cardiac alterations and increased oxidative stress in cardiomyopathic hamsters. Male Syrian cardiomyopathic and age-matched inbred control hamsters received ASA orally from the age of 60 days. Animals were sacrificed at the age of 150, 250, and 350 days to evaluate the time course of cardiac hypertrophy and cardiovascular tissue superoxide anion (O(2)(-)) production. At the age of 150 days, the ventricular weight over body weight ratio, resting heart rate, and cardiovascular O(2)(-) production were much higher in cardiomyopathic hamsters than those in control. At the age of 250 days, in addition to the continual deterioration of these parameters with age, the blood pressure started to fall and the signs of heart failure appeared. In these cardiomyopathic hamsters, chronic ASA treatment (a) completely prevented elevated O(2)(-) production and the NAD(P)H oxidase activity, (b) significantly slowed down the development of the cardiac hypertrophy and fibrosis. Chronic ASA treatment significantly prevents the deterioration of cardiac function and structure as well as the increased oxidative stress in the cardiomyopathic hamster. Our findings suggest that ASA presents a therapeutic potential to prevent cardiac dysfunction.

  13. Effects of diurnal variation and anesthetic agents on intraocular pressure in Syrian hamsters (Mesocricetus auratus).

    PubMed

    Rajaei, Seyed Mehdi; Mood, Maneli Ansari; Paryani, Mohammad Reza; Williams, David L

    2017-01-01

    OBJECTIVE To determine effects of diurnal variation and anesthetic agents on intraocular pressure (IOP) in Syrian hamsters (Mesocricetus auratus). ANIMALS 90 healthy adult Syrian hamsters (45 males and 45 females). PROCEDURES IOP was measured with a rebound tonometer. In phase 1, IOP was measured in all hamsters 3 times during a 24-hour period (7 am, 3 pm, and 11 pm). In phase 2, hamsters were assigned to 5 groups (18 animals [9 males and 9 females]/group). Each group received an anesthetic agent or combination of anesthetic agents (ketamine hydrochloride, xylazine hydrochloride, diazepam, ketamine-diazepam [KD], or ketamine-xylazine [KX] groups) administered via the IP route. The IOP was measured before (time 0 [baseline]) and 10, 30, 60, 90, 120, and 150 minutes after administration of drugs. RESULTS Mean ± SD IOP values were 2.58 ± 0.87 mm Hg, 4.46 ± 1.58 mm Hg, and 5.96 ± 1.23 mm Hg at 7 am, 3 pm, and 11 pm, respectively. Mean baseline IOP was 6.25 ± 0.28 mm Hg, 6.12 ± 0.23 mm Hg, 5.75 ± 0.64 mm Hg, 5.12 ± 1.40 mm Hg, and 4.50 ± 1.30 mm Hg for the ketamine, xylazine, diazepam, KD, and KX groups, respectively. A significant decrease in IOP, compared with baseline IOP, was detected in only the KX group at 30, 60, and 90 minutes after drug administration. CONCLUSIONS AND CLINICAL RELEVANCE Maximum IOP in Syrian hamsters was detected at night. The ketamine-xylazine anesthetic combination significantly decreased IOP in Syrian hamsters.

  14. Both soybean and kudzu phytoestrogens modify favorably the blood lipoprotein profile in ovariectomized and castrated hamsters.

    PubMed

    Guan, Lei; Yeung, Sai Ying Venus; Huang, Yu; Chen, Zhen-Yu

    2006-06-28

    The present study compared the hypolipidemic activity of kudzu phytoestrogens with that of soybean phytoestrogen in estrogen- and androgen-deficient hamsters. In the first experiment, ovariectomized hamsters (n = 37) were randomly divided into four groups (n = 9-10 each group). The first group was the control group, whereas the second group had the time-releasing estradiol-17beta subcutaneous (pellet) implants as a positive control. The third and fourth groups were orally administered soybean or kudzu phytoestrogen extracts (30 mg/kg of body weight) per day. In the second experiments, the first group of male hamsters (n = 9) received a sham operation, whereas the other three groups of male hamsters (n = 9 each) were castrated. The castrated control group received orally distilled water, whereas the second and third castrated groups were orally given 30 mg/kg soybean or kudzu phytoestrogen extracts. The results for the first experiment showed that the ovariectomized hamsters orally given soybean and kudzu phytoestrogen extracts had significantly decreased serum total cholesterol (TC) and non-high-density lipoprotein cholesterol (non-HDL-C) with HDL cholesterol (HDL-C) being unaffected. The data from the second experiment demonstrated that administration of soybean but not kudzu phytoestrogen extracts decreased significantly serum TC. However, administration of kudzu phytoestrogens caused redistribution of cholesterol among lipoproteins, leading to a significant decrease in the ratio of non-HDL-C to HDL-C. It was concluded that both soybean and kudzu phytoestrogens could modify favorably lipoprotein profiles in ovariectomized and castrated hamsters.

  15. Identification of the molecular sex-differentiation period in the Siberian sturgeon.

    PubMed

    Vizziano-Cantonnet, Denise; Di Landro, Santiago; Lasalle, André; Martínez, Anabel; Mazzoni, Talita Sarah; Quagio-Grassiotto, Irani

    2016-01-01

    Sexual development prior to gonadal sex differentiation is regulated by various molecular mechanisms. In fish, a "molecular sex-differentiation period" has been identified in species for which sex can be ascertained prior to gonadal sex differentiation. The present study was designed to identify such a period in a species for which no genetic sex markers or monosex populations are available. Siberian sturgeons undergo a slow sex-differentiation process over several months, so gonad morphology and gene expression was tracked in fish from ages 3-27 months to identify the sex-differentiation period. The genes amh, sox9, and dmrt1 were selected as male gonad markers; cyp19a1a and foxl2a as female gonad markers; and cyp17a1 and ar as markers of steroid synthesis and steroid receptivity. Sex differentiation occurred at 8 months, and was preceded by a molecular sex-differentiation period at 3-4 months, at which time all of the genes except ar showed clear expression peaks. amh and sox9 expression seemed to be involved in male sexual development whereas dmrt1, a gene involved in testis development in metazoans, unexpectedly showed a pattern similar to those of the genes known to be involved in female gonadal sex differentiation (cyp19a1 and foxl2a). In conclusion, the timing of and gene candidates involved with molecular sex differentiation in the Siberian sturgeon were identified. © 2015 Wiley Periodicals, Inc.

  16. The Environmental Impact of Siberian Traps Volcanism

    NASA Astrophysics Data System (ADS)

    Saunders, A. D.; Reichow, M. K.

    2008-12-01

    New high-precision 40Ar/39Ar data confirm that the Siberian Traps extend as far west as the Ural Mountains, and from the Kuznetsk Basin in the south to the Taimyr Peninsula in the north; an area encompassing some 5 million km2. The bulk of this volcanism occurred at about 250 Ma (Ar-Ar time). These data, plus new and published Ar/Ar data from the P-Tr section at Meishan, China, confirm that volcanism and the mass extinction were synchronous. Here, we explore the causal link between volcanism and extinction. The volcanism is associated with global super-greenhouse conditions and widespread shallow oceanic anoxia - perhaps the sine qua non of the marine mass extinctions. Injection of isotopically 'light' carbon is required to explain the characteristic and dramatic negative carbon isotope excursion preserved in ocean water proxies, but because the CIE occurs after the mass extinction, this suggests that the carbon pulse (from breakdown of methane hydrates, or magmatic burning of coal or other hydrocarbons) was not the fundamental cause of the extinction. Rather, we suggest that magmatic CO2 released during the eruptions (complemented by pyrogenetic CO2 and methane) led to progressive CO2 accumulation in the atmosphere-ocean system (rates of long-term removal of carbon by geological processes are significantly lower than volcanic injection). Atmospheric accumulation may have been amplified by short-term sulphate-induced volcanic winters that caused collapse of photosynthetic cycles by atmospheric temperature fluctuations and sunlight attenuation, thus inhibiting carbon draw-down. Subsequent warming of the deep ocean may have triggered the methane pulse, leading to the main CIE. What lessons can we take away for present climate change? Unlike in the Cenozoic, when atmospheric CO2 progressively decreased to low pre-industrial levels, throughout the Permian atmospheric CO2 levels fluctuated strongly, and may have been as much as 10x present-day by the time that Siberian

  17. Taste reactivity in the hamster.

    PubMed

    Brining, S K; Belecky, T L; Smith, D V

    1991-06-01

    Taste reactivity, which was first described in the rat, consists of ingestive and aversive response components, the latter seen mostly to bitter-tasting stimuli. The present experiment characterized the hamster's taste reactivity to an array of stimuli (sugars: 1 M sucrose, d-fructose and d-glucose; sodium salts: 1 M NaCl, Na2SO4 and NaNO3; acids: 30 mM HCl, tartaric acid and citric acid; bitter-tasting stimuli: 100 mM quinine hydrochloride and nicotine sulfate and 10 mM denatonium benzoate). These 12 stimuli were chosen to represent 3 examples each of stimuli that taste sweet, salty, sour, or bitter to humans; they were presented in random order via an intraoral fistula, one stimulus each day per animal (n = 10). Infusions of 0.6 ml were delivered over a 1-min period from a syringe pump. Orofacial and somatic motor responses were recorded on videotape for later analysis and were also coded online into a computer. Ingestive responses included forward and lateral tongue protrusions and aversive responses included gaping, chin rubbing, forelimb flailing, fluid rejection, increased locomotion, and aversive posturing. Each stimulus group produced a characteristic pattern of these behaviors, with sugars eliciting only ingestive behaviors and the bitter stimuli evoking predominantly aversive responses. Both sodium salts and acids produced ingestive responses, as seen previously in the rat, although these stimuli also elicited aversive behaviors in the hamster, including apes. The patterns of responses were characterized using multivariate procedures; the stimuli fell into distinct groups that were separated primarily along an hedonic dimension.

  18. Induction of lyme arthritis in LSH hamsters

    SciTech Connect

    Schmitz, J.L.; Schell, R.F.; Hejka, A.; England, D.M.; Konick, L.

    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 were 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.

  19. Spontaneous endomyometrial neoplasms in aging Chinese hamsters

    SciTech Connect

    Brownstein, D.G.; Brooks, A.L.

    1980-05-01

    Twenty-one endomyometrial neoplasms among 93 nulliparous noninbred Chinese hamsters were evaluated. The median survival time of the 93 females was 1040 days. The median age of hamsters with endomyometrial neoplasms was 1200 days. Neoplasms were classified as carcinomas or malignant mixed muellerian tumors of the endometrium and benign or malignant myometrial neoplasms. There were 13 endometrial adenocarcinomas. Three tumors were mixed adenosquamous carcinomas, which occurred in significantly older Chinese hamsters than did adenocarcinomas. Three malignant mixed muellerian tumors consisted of 2 carcinosarcomas and 1 mixed mesodermal tumor. The 2 myometrial neoplasms were a lelomyoma and a lelomyosarcoma. The classification and relative frequency of these neoplasms were similar to endomyometrial neoplasms of women, which makes Chinese hamsters useful subjects for studies of spontaneous endomyometrial cancers.

  20. Two new species of Chrysotus Meigen (Diptera, Dolichopodidae) from Siberia, with a key to the Siberian species.

    PubMed

    Negrobov, Oleg P; Barkalov, Anatolij V; Selivanova, Olga V

    2014-06-16

    Two new species from the southern tundra of the Taimyr Peninsula (Russia) are described. Chrysotus tricaudatus Negrobov, Barkalov & Selivanova sp. nov. is similar to C. albibarbus Loew, but can be distinguished by its brown palpus with black setae, yellow hind tibia and base of hind tarsus, and features of the male genitalia. Chrysotus komovi Negrobov, Barkalov & Selivanova sp. nov. is similar to C. obscuripes Zetterstedt, but can be distinguished by features of the male genitalia. A key to all Siberian species of the genus is also presented along with figures of diagnostic morphological characters. 

  1. Neurobehavioural development of the golden hamster.

    PubMed

    Da Silva, V A; Smart, J L; Freire, E M; Paumgartten, F J

    1989-01-01

    The aim of this study was to establish a developmental profile for the golden hamster by using a systematic sequence of test procedures. One experimentally naive litter was tested each day from 0 to 25 days of postnatal age. The appearance of developmental landmarks (physical features and reflexes), spontaneous behaviour in an open field, homing behaviour and rota rod performance were studied. Infant mortality through infanticide was recorded in undisturbed and tested hamsters. The results indicated that most of the tests employed in the present study can be applied usefully in the evaluation of the neurobehavioural development of the golden hamster. The developmental profile for this species is described in detail. In comparison to rats and mice, hamsters display accelerated development of a number of characteristics, most notably incisor eruption and vaginal opening. Infanticide, the most troublesome problem in studies in which hamster litters must be disturbed, did not occur after day 3. As most reflexes and sensory abilities develop after this age, hamster pups can be used successfully in behavioural teratology evaluation.

  2. Wildfires Dynamics in Siberian Larch Forests

    NASA Technical Reports Server (NTRS)

    Ponomarev, Evgenii I.; Kharuk, Viacheslav I.; Ranson, Kenneth J.

    2016-01-01

    Wildfire number and burned area temporal dynamics within all of Siberia and along a south-north transect in central Siberia (45deg-73degN) were studied based on NOAA/AVHRR (National Oceanic and Atmospheric Administration/ Advanced Very High Resolution Radiometer) and Terra/MODIS (Moderate Resolution Imaging Spectroradiometer) data and field measurements for the period 1996-2015. In addition, fire return interval (FRI) along the south-north transect was analyzed. Both the number of forest fires and the size of the burned area increased during recent decades (p < 0.05). Significant correlations were found between forest fires, burned areas and air temperature (r = 0.5) and drought index (The Standardized Precipitation Evapotranspiration Index, SPEI) (r = 0.43). Within larch stands along the transect, wildfire frequency was strongly correlated with incoming solar radiation (r = 0.91). Fire danger period length decreased linearly from south to north along the transect. Fire return interval increased from 80 years at 62 N to 200 years at the Arctic Circle (6633' N), and to about 300 years near the northern limit of closed forest stands (about 71+ N). That increase was negatively correlated with incoming solar radiation (r = 0.95). Keywords: wildfires; drought index; larch stands; fire return interval; fire frequency; burned area; climate-induced trends in Siberian wildfires

  3. Effect of Exercise on Photoperiod-Regulated Hypothalamic Gene Expression and Peripheral Hormones in the Seasonal Dwarf Hamster Phodopus sungorus

    PubMed Central

    Petri, Ines; Dumbell, Rebecca; Scherbarth, Frank; Steinlechner, Stephan; Barrett, Perry

    2014-01-01

    The Siberian hamster (Phodopus sungorus) is a seasonal mammal responding to the annual cycle in photoperiod with anticipatory physiological adaptations. This includes a reduction in food intake and body weight during the autumn in anticipation of seasonally reduced food availability. In the laboratory, short-day induction of body weight loss can be reversed or prevented by voluntary exercise undertaken when a running wheel is introduced into the home cage. The mechanism by which exercise prevents or reverses body weight reduction is unknown, but one hypothesis is a reversal of short-day photoperiod induced gene expression changes in the hypothalamus that underpin body weight regulation. Alternatively, we postulate an exercise-related anabolic effect involving the growth hormone axis. To test these hypotheses we established photoperiod-running wheel experiments of 8 to 16 weeks duration assessing body weight, food intake, organ mass, lean and fat mass by magnetic resonance, circulating hormones FGF21 and insulin and hypothalamic gene expression. In response to running wheel activity, short-day housed hamsters increased body weight. Compared to short-day housed sedentary hamsters the body weight increase was accompanied by higher food intake, maintenance of tissue mass of key organs such as the liver, maintenance of lean and fat mass and hormonal profiles indicative of long day housed hamsters but there was no overall reversal of hypothalamic gene expression regulated by photoperiod. Therefore the mechanism by which activity induces body weight gain is likely to act largely independently of photoperiod regulated gene expression in the hypothalamus. PMID:24603871

  4. Chronic pulmonary toxicity study of indium-tin oxide and indium oxide following intratracheal instillations into the lungs of hamsters.

    PubMed

    Tanaka, Akiyo; Hirata, Miyuki; Homma, Toshiaki; Kiyohara, Yutaka

    2010-01-01

    The aim of this study was to clarify the chronic toxicological effects of indium-tin oxide (ITO) and indium oxide (In(2)O(3)) on laboratory animals. Male Syrian golden hamsters were intratracheally administered 3 mg/kg or 6 mg/kg of ITO particles, or 2.7 mg/kg or 5.4 mg/kg of In(2)O(3) particles, containing 2.2 mg/kg or 4.5 mg/kg of indium, twice a week, for 8 wk. Control hamsters were given vehicle of distilled water only. The hamsters were euthanized serially up to 78 wk after the final instillation and the toxicological effects were determined. Body weight gain was significantly suppressed in the ITO 6 mg/kg-treated hamsters compared with the control group, but not in the ITO 3 mg/kg-treated or In(2)O(3)-treated hamsters. Relative lung weights among all the indium-treated groups were significantly increased compared to that in the control group throughout the observation period. The serum indium concentration among all the indium-treated groups gradually increased up to the end of the observation period. Histopathologically, foci of slight to severe pulmonary inflammatory response with diffuse alveolar or bronchiolar cell hyperplasia, expansion of the alveolar spaces and interstitial fibrotic proliferation were present in all the indium-treated hamsters and the severity of these lesions worsened with the passage of time. Lung benign adenomas were only manifest in 3 out of 15 of the ITO 6 mg/kg-treated hamsters. The present results clearly demonstrate that ITO and In(2)O(3) particles caused chronic pulmonary toxicity when repeated intratracheal instillations were given to hamsters.

  5. A comparison of liver protein changes in mice and hamsters treated with the peroxisome proliferator Wy-14,643.

    SciTech Connect

    Giometti, C. S.; Tollaksen, S. L.; Cunningham, M. L.; Center for Mechanistic Biology and Biotechnology; National Inst. of Environmental Health Sciences

    1998-01-01

    Interspecies differences in the liver response to Wy-14,643, a potent peroxisome proliferator in rats and mice, have been demonstrated. While both rats and mice show dramatic increases in the number of peroxisomes, the activity of peroxisomal enzymes involved in the {beta}-oxidation of fatty acids, and heptocyte replication, Syrian hamsters have a more moderate peroxisome proliferation response and no sustained increase in cell replication. Rats and mice, but not hamsters, develop hepatocellular carcinoma after prolonged exposure to Wy-14,643. To further characterize this species difference, two-dimensional gel electrophoresis (2-DE) has been used to compare the effect of 14-day exposure to various dietary concentrations of Wy-14,643 on liver protein expression in male mice and hamsters. Digitized images of the 2-DE protein maps were searched for significant changes. The peroxisome bifunctional enzyme (PBE) enoyl CoA hydratase/3-hydroxyacyl dehydrogenase, which migrates to the same position in mouse and hamster liver protein 2-DE patterns, increased in abundance by more than three times the control level in both mice and hamsters. In addition to the quantitative change in PBE, significant quantitative changes (P < 0.001) were found in 49 mouse liver proteins (47 decreasing and 2 increasing) and in 35 hamster liver proteins (27 decreasing and 8 increasing). There was little overlap in the mouse and hamster proteins showing quantitative changes in response to Wy-14,643, with the exception of PBE and one unidentified liver protein with an approximate molecular weight of 50 000. These results show that although peroxisome proliferation occurs in the livers of both mice and hamsters exposed to Wy-14,643, other species-specific changes in proteins occur that are independent of the peroxisome proliferation response and that could be related to species-specific susceptibility or resistance to liver tumor induction.

  6. Hydrogen gas attenuates embryonic gene expression and prevents left ventricular remodeling induced by intermittent hypoxia in cardiomyopathic hamsters.

    PubMed

    Kato, Ryuji; Nomura, Atsuo; Sakamoto, Aiji; Yasuda, Yuki; Amatani, Koyuha; Nagai, Sayuri; Sen, Yoko; Ijiri, Yoshio; Okada, Yoshikatsu; Yamaguchi, Takehiro; Izumi, Yasukatsu; Yoshiyama, Minoru; Tanaka, Kazuhiko; Hayashi, Tetsuya

    2014-12-01

    The prevalence of sleep apnea is very high in patients with heart failure (HF). The aims of this study were to investigate the influence of intermittent hypoxia (IH) on the failing heart and to evaluate the antioxidant effect of hydrogen gas. Normal male Syrian hamsters (n = 22) and cardiomyopathic (CM) hamsters (n = 33) were exposed to IH (repeated cycles of 1.5 min of 5% oxygen and 5 min of 21% oxygen for 8 h during the daytime) or normoxia for 14 days. Hydrogen gas (3.05 vol/100 vol) was inhaled by some CM hamsters during hypoxia. IH increased the ratio of early diastolic mitral inflow velocity to mitral annulus velocity (E/e', 21.8 vs. 16.9) but did not affect the LV ejection fraction (EF) in normal Syrian hamsters. However, IH increased E/e' (29.4 vs. 21.5) and significantly decreased the EF (37.2 vs. 47.2%) in CM hamsters. IH also increased the cardiomyocyte cross-sectional area (672 vs. 443 μm(2)) and interstitial fibrosis (29.9 vs. 9.6%), along with elevation of oxidative stress and superoxide production in the left ventricular (LV) myocardium. Furthermore, IH significantly increased the expression of brain natriuretic peptide, β-myosin heavy chain, c-fos, and c-jun mRNA in CM hamsters. Hydrogen gas inhalation significantly decreased both oxidative stress and embryonic gene expression, thus preserving cardiac function in CM hamsters. In conclusion, IH accelerated LV remodeling in CM hamsters, at least partly by increasing oxidative stress in the failing heart. These findings might explain the poor prognosis of patients with HF and sleep apnea. Copyright © 2014 the American Physiological Society.

  7. IMPACT OF WHEEL RUNNING ON CHRONIC ETHANOL INTAKE IN AGED SYRIAN HAMSTERS

    PubMed Central

    Brager, Allison J.; Hammer, Steven B.

    2012-01-01

    Introduction 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. Methods 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. Results 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. Discussion 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. PMID:23022151

  8. Comparative Metabolism of Carbon Tetrachloride in Rats, Mice and Hamsters Using Gas Uptake and PBPK Modeling

    SciTech Connect

    Thrall, Karla D. ); Vucelick, Mark E.; Gies, Richard A. ); Zangar, Richard C. ); Weitz, Karl K. ); Poet, Torka S. ); Springer, David L. ); Grant, Donna M. ); Benson, Janet M.

    2000-08-25

    No study has comprehensively compared the rate of metabolism of carbon tetrachloride (CCl4) across species. Therefore, the in vivo metabolism of CCl4 was evaluated using groups of male animals (F344 rats, B6C3F1 mice, and Syrian hamsters) exposed to 40-1800 ppm CCl4 in a closed, recirculating gas-uptake system. For each species, an optimal fit of the family of uptake curves was obtained by adjusting Michaelis-Menten metabolic constants Km (affinity) and Vmax (capacity) using a physiologically based pharmacokinetic (PBPK) model. The results show that the mouse has a slightly higher capacity and lower affinity for metabolizing CCl4 compared to the rat, while the hamster has a higher capacity and lower affinity than either rat or mouse. A comparison of the Vmax to Km ratio, normalized for mg of liver protein (L/hr/mg) across species indicates that hamsters metabolize more CCl4 than either rats or mice, and should be more susceptible to CCl4-induced hepatotoxicity. These species comparisons were evaluated against toxicokinetic studies conducted in animals exposed by nose-only inhalation to 20 ppm 14C-labeled CCl4 for 4 hours. The toxicokinetic study results are consistent with the in vivo rates of metabolism, with rats eliminating less radioactivity associated with metabolism (14CO2 and urine/feces) and more radioactivity associated with the parent compound (radioactivity trapped on charcoal) compared to either hamsters or mice. The in vivo metabolic constants determined here, together with in vitro constants determined using rat, mouse, hamster and human liver microsomes, were used to estimate human in vivo metabolic rates of 1.49 mg/hr/kg body weight and 0.25 mg/L for Vmax and Km, respectively. Normalizing the rate of metabolism (Vmax/Km) by mg liver protein, the rate of metabolism of CCl4 differs across species, with hamster > mouse& > rat > human.

  9. The 96-antenna multifrequency Siberian radioheliograph

    NASA Astrophysics Data System (ADS)

    Lesovoi, Sergey; Altyntsev, Alexander; Ivanov, Eugene; Kashapova, Larisa

    2013-04-01

    The 96-antenna multifrequency Siberian radioheliograph, which is under construction at present, is described. The frequency range of the radioheliograph is from 4 up to 8 GHz. The radioheliograph data are complex cross-correlations for both circular polarizations at a number of frequencies from a given list. The longest baseline is of 622 m. This provides an angular resolution down to 13 arcsec at 8 GHz. The shortest baseline (fundamental spacing) is of 4.9 m. Because of such fundamental spacing one can completely avoid the spatial aliasing at frequencies below 6 GHz. The images at frequencies between 6 GHz and 8 GHz are non-aliased during most of the observation time. We plan to reach the sensitivity about 100 K for the snapshot (1 s cadence) image. Wideband antennas with front-ends, analog back-ends, digital receivers and a correlator are described. A signal from each antenna is transmitted to a workroom by the analog fiber optical link. After mixing, all signals are digitized and processed by digital receivers before the data are transmitted to the correlator. The digital receivers and the correlator are virtually FPGA IP cores. So there are many ways to the delay tracking and fringe stopping. The fractional sample delay for delay tracking is described in detail. Also the choice of a number of quantization levels of the correlator is discussed. The joint analysis of HXR and microwave spectral data, recorded with the radioheliograph prototype at a number of frequencies is presented. It is shown that the dependence of brightness temperature on spatial size of microwave sources could be used to determine moments when particle acceleration occurs. The work is supported by the Ministry of education and science of the Russian Federation (State Contracts 16.518.11.7065 and 02.740.11.0576), and by the grants RFBR (12-02-91161-GFEN-a, 12-02-00616 and 12-02-00173-a

  10. Siberian Apparent Polar Wander Path for the Phanerozoic Eon: towards finding Siberian place on Earth

    NASA Astrophysics Data System (ADS)

    Blanco, D.; Kravchinsky, V. A.; Kabin, K.

    2011-12-01

    The existence of Siberia as an independent stable platform can be traced back with accuracy from the breakup of Rodinia (~800 Ma) until the end of the Paleozoic Eon when it became part of Eurasia. Different continental blocks accreted to Siberia since Precambrian forming one of the largest tectonic structures on Earth - Siberian continent. At the same time Siberian apparent polar wander path (APWP), which is crucial for global tectonic reconstructions, still contain long unresolved segments. Cocks and Torsvik (2007) compiled the available paleomagnetic poles from Siberia and applied smoothing methods to construct the APWP. We updated the available paleomagnetic pole list with recently published poles for the Paleozoic and Mesozoic Eras. In order to ensure the reliability of the data, we considered only poles available in international journals and followed the Van der Voo's (1993) selection criteria. We excluded the poles that did not have well described age constrains or acceptable experimental procedures. In terms of the APWP construction, we applied several techniques that enabled us to reconstruct the APWP segments where paleomagnetic poles were absent from the database. As a first approach, we approximated APWP using a least-squares fit computed through singular value decomposition. The advantage of the method was in its numerical stability and ease of application to either dense or sparse data sets. The second technique we used was based on smoothing techniques, similar to those by Cocks and Torsvik (2007). However, the large number of degrees of freedom for the smoothing method might lead to excessively effective approximation and thus transcribe the noise (De Boor, 2001). The effectiveness of both approaches was demonstrated by excellent comparison with very well resolved APWP for Europe (Torsvik et al., 2001). Subsequently we reconstructed the APWP for Siberia applying and comparing both of our techniques for the Phanerozoic Eon. Two sets of

  11. Contrasting patterns of Y-chromosome variation in South Siberian populations from Baikal and Altai-Sayan regions.

    PubMed

    Derenko, Miroslava; Malyarchuk, Boris; Denisova, Galina A; Wozniak, Marcin; Dambueva, Irina; Dorzhu, Choduraa; Luzina, Faina; Miścicka-Sliwka, Danuta; Zakharov, Ilia

    2006-01-01

    In order to investigate the genetic history of autochthonous South Siberian populations and to estimate the contribution of distinct patrilineages to their gene pools, we have analyzed 17 Y-chromosomal binary markers (YAP, RPS4Y(711), SRY-8299, M89, M201, M52, M170, 12f2, M9, M20, 92R7, SRY-1532, DYS199, M173, M17, Tat, and LLY22 g) in a total sample of 1,358 males from 14 ethnic groups of Siberia (Altaians-Kizhi, Teleuts, Shors, Tuvinians, Todjins, Tofalars, Sojots, Khakassians, Buryats, Evenks), Central/Eastern Asia (Mongolians and Koreans) and Eastern Europe (Kalmyks and Russians). Based on both, the distribution pattern of Y-chromosomal haplogroups and results on AMOVA analysis we observed the statistically significant genetic differentiation between the populations of Baikal and Altai-Sayan regions. We suggest that these regional differences can be best explained by different contribution of Central/Eastern Asian and Eastern European paternal lineages into gene pools of modern South Siberians. The population of the Baikal region demonstrates the prevalence of Central/Eastern Asian lineages, whereas in the populations of Altai and Sayan regions the highest paternal contribution resulted from Eastern European descent is revealed. Yet, our data on Y-chromosome STRs variation demonstrate the clear differences between the South Siberian and Eastern European R1a1-lineages with the evolutionary ages compatible with divergence time between these two regional groups.

  12. Serotoninergic system in hamster skin.

    PubMed

    Slominski, Andrzej; Pisarchik, Alexander; Semak, Igor; Sweatman, Trevor; Szczesniewski, Andre; Wortsman, Jacobo

    2002-10-01

    We have cloned the tryptophan hydroxylase cDNA from hamster pituitary and demonstrated its expression in the skin, melanotic and amelanotic melanomas, spleen, heart, and the eye. We further demonstrated that skin, melanomas, spleen, pituitary, and eye but not heart expressed arylalkylamine N-acetyltransferase mRNA. The cutaneous expression of the arylalkylamine N-acetyltransferase gene was accompanied by enzymatic activity for the conversion of serotonin and tryptamine to N-acetylserotonin and N-acetyltryptamine, respectively. There was marked regional variation in the serotonin N-acetyltransferase activity, which was higher in ear skin than in corpus skin, and was lower in melanomas than in normal skin. Serotonin N-acetyltransferase activity was significantly inhibited by Cole bisubstrate at low concentration (

  13. Social forces can impact the circadian clocks of cohabiting hamsters

    PubMed Central

    Paul, Matthew J.; Indic, Premananda; Schwartz, William J.

    2014-01-01

    A number of field and laboratory studies have shown that the social environment influences daily rhythms in numerous species. However, underlying mechanisms, including the circadian system's role, are not known. Obstacles to this research have been the inability to track and objectively analyse rhythms of individual animals housed together. Here, we employed temperature dataloggers to track individual body temperature rhythms of pairs of cohabiting male Syrian hamsters (Mesocricetus auratus) in constant darkness and applied a continuous wavelet transform to determine the phase of rhythm onset before, during, and after cohabitation. Cohabitation altered the predicted trajectory of rhythm onsets in 34% of individuals, representing 58% of pairs, compared to 12% of hamsters single-housed as ‘virtual pair’ controls. Deviation from the predicted trajectory was by a change in circadian period (τ), which tended to be asymmetric—affecting one individual of the pair in nine of 11 affected pairs—with hints that dominance might play a role. These data implicate a change in the speed of the circadian clock as one mechanism whereby social factors can alter daily rhythms. Miniature dataloggers coupled with wavelet analyses should provide powerful tools for future studies investigating the principles and mechanisms mediating social influences on daily timing. PMID:24500164

  14. The Effects of Vaccinium myrtillus Extract on Hamster Pial Microcirculation during Hypoperfusion-Reperfusion Injury

    PubMed Central

    Mastantuono, Teresa; Starita, Noemy; Sapio, Daniela; D’Avanzo, Sabato Andrea; Di Maro, Martina; Muscariello, Espedita; Paterni, Marco; Colantuoni, Antonio; Lapi, Dominga

    2016-01-01

    Introduction The present study was aimed to assess the in vivo hamster pial microvessel alterations due to 30 min transient bilateral common carotid artery occlusion (BCCAO) and reperfusion (60 min); moreover, the neuroprotective effects of Vaccinium myrtillus extract, containing 34.7% of anthocyanins, were investigated. Materials and Methods Two groups of male hamsters were used: the first fed with control diet and the other with Vaccinium myrtillus supplemented diet. Hamster pial microcirculation was visualized by fluorescence microscopy through an open cranial window. Pial arterioles were classified according to Strahler’s method. Results In age-matched control diet-fed hamsters, BCCAO caused a decrease in diameter of all arterioles. At the end of reperfusion, the reduction of diameter in order 3 arterioles was by 8.4 ± 3.1%, 10.8 ± 2.3% and 12.1 ± 1.1% of baseline in the 2, 4 and 6 month control diet-fed hamsters, respectively. Microvascular permeability and leukocyte adhesion were markedly enhanced, while perfused capillary length (PCL) decreased. The response to acetylcholine and papaverine topical application was impaired; 2’-7’-dichlorofluoresceine-diacetate assay demonstrated a significant ROS production. At the end of BCCAO, in age-matched Vaccinium myrtillussupplemented diet-fed hamsters, the arteriolar diameter did not significantly change compared to baseline. After 60 min reperfusion, order 3 arterioles dilated by 9.3 ± 2.4%, 10.6 ± 3.1% and 11.8 ± 2.7% of baseline in the 2, 4 and 6 month Vaccinium myrtillus supplemented diet-fed hamsters, respectively. Microvascular leakage and leukocyte adhesion were significantly reduced in all groups according to the time-dependent treatment, when compared with the age-matched control diet-fed hamsters. Similarly, the reduction in PCL was progressively prevented. Finally, the response to acetylcholine and papaverine topical application was preserved and there was no significant increase in ROS

  15. Histopathology of Lyme arthritis in LSH hamsters

    SciTech Connect

    Hejka, A.; Schmitz, J.L.; England, D.M.; Callister, S.M.; Schell, R.F.

    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 was 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.

  16. Ivermectin treatment of demodicosis in 56 hamsters.

    PubMed

    Tani, K; Iwanaga, T; Sonoda, K; Hayashiya, S; Hayashiya, M; Taura, Y

    2001-11-01

    Fifty-six hamsters with demodicosis were treated with daily oral administration of ivermectin (0.3 mg/kg). Thirty-three cases (58.9%) were cured and 6 cases (10.7%) had improved clinically but needed to continue treatment. Of 5 cases (8.9%) who relapsed within 3 months and were retreated with ivermectin, 4 were cured and 1 needed further treatment. Five cases (8.9%) had improved clinically but died within 3 months. Seven cases (12.5%) had not improved and died within 3 months. Overall 49 (87.5%) hamsters had improved clinically. No significant differences in prognosis of demodicosis were detected according to sex, breed, age and clinical features, but the prognosis of demodicosis in hamsters with concurrent disease was poor.

  17. Aminostratigraphy of Organisms in Antarctic and Siberian Permafrost Cores

    NASA Technical Reports Server (NTRS)

    Brinton, K. L. F.; Tsapin, A. I.; McDonald, G. D.; Gilichinsky, D.

    1999-01-01

    Amino acid racemization dating (or aminostratigraphy) in Antarctic and Siberian permafrost core samples can be used to evaluate the age of organisms in frozen environments. The potential for subsurface permafrost on Mars makes terrestrial permafrost an important source of information regarding the preservation of both living organisms and their remains. Additional information is contained in the original extended abstract.

  18. Improved Establishment Characteristics of 'Vavilov II' Siberian Wheatgrass

    USDA-ARS?s Scientific Manuscript database

    'Vavilov II' Siberian wheatgrass (Agropyron fragile (Roth) Candargy) was developed for reseeding disturbed rangelands dominated by annual weeds as a result of severe disturbance, frequent fires, and soil erosion. Selection emphasis in Vavilov II was on seedling establishment and plant persistence. ...

  19. Effectiveness of Science Tasks and Plans for Siberian Scholars.

    ERIC Educational Resources Information Center

    Marchuk, G. I.

    1972-01-01

    Science and Technology research plans formulated for the Siberian Department of the U.S.S.R. Academy of Sciences are analyzed in this article to illustrate the tasks of scholars, workers, and engineering and technical personnel in the fulfillment of the 24th party congress resolutions The hypothesis of developing Siberia and the Far East up to the…

  20. Effectiveness of Science Tasks and Plans for Siberian Scholars.

    ERIC Educational Resources Information Center

    Marchuk, G. I.

    1972-01-01

    Science and Technology research plans formulated for the Siberian Department of the U.S.S.R. Academy of Sciences are analyzed in this article to illustrate the tasks of scholars, workers, and engineering and technical personnel in the fulfillment of the 24th party congress resolutions The hypothesis of developing Siberia and the Far East up to the…

  1. The Value Priorities of Young People in the Siberian Region

    ERIC Educational Resources Information Center

    Orlova, V. V.

    2010-01-01

    This article discusses the implications of the survey results involving young people in the Siberian Region on their value priorities. In the process of their socialization, special importance attaches to the problem of the value priorities of young people. Among these, in the authors opinion, it is possible to single out both spiritual and moral…

  2. Intra- and interspecific hybridization in invasive Siberian elm

    USDA-ARS?s Scientific Manuscript database

    Although numerous studies have examined the invasion history of herbaceous plants, few studies have investigated the invasion biology of woody plants. In this study, we determined whether inter-specific hybridization was necessary before invasiveness could evolve in the Siberian elm, Ulmus pumila. P...

  3. Oil and Gas Resources of the West Siberian Basin, Russia

    EIA Publications

    1997-01-01

    Provides an assessment of the oil and gas potential of the West Siberian Basin of Russia. The report was prepared in cooperation with the U. S. Geological Survey (USGS) and is part of the Energy Information Administration's (EIA) Foreign Energy Supply Assessment Program (FESAP).

  4. Pulmonary Tuberculosis due to Mycobacterium bovis in Captive Siberian Tiger

    PubMed Central

    Lantos, Ákos; Niemann, Stefan; Mezősi, László; Sós, Endre; Erdélyi, Károly; Dávid, Sándor; Parsons, Linda M.; Kubica, Tanja; Rüsch-Gerdes, Sabine

    2003-01-01

    We report the first case of pulmonary tuberculosis caused by Mycobacterium bovis subsp. caprae in a captive Siberian tiger, an endangered feline. The pathogen was isolated from a tracheal aspirate obtained by bronchoscopy. This procedure provided a reliable in vivo diagnostic method in conjunction with conventional and molecular tests for the detection of mycobacteria. PMID:14718093

  5. The Value Priorities of Young People in the Siberian Region

    ERIC Educational Resources Information Center

    Orlova, V. V.

    2010-01-01

    This article discusses the implications of the survey results involving young people in the Siberian Region on their value priorities. In the process of their socialization, special importance attaches to the problem of the value priorities of young people. Among these, in the authors opinion, it is possible to single out both spiritual and moral…

  6. An assessment of anti-Müllerian hormone in predicting mating outcomes in female hamsters that have undergone natural and chemically-accelerated reproductive aging.

    PubMed

    Roosa, Kristen A; Zysling, Devin A; Place, Ned J

    2015-04-01

    In mammals, female fertility declines with age due in part to a progressive loss of ovarian follicles. The rate of follicle decline varies among individuals making it difficult to predict the age of onset of reproductive senescence. Serum anti-Müllerian hormone (AMH) concentrations correlate with the numbers of ovarian follicles, and therefore, AMH could be a useful predictor of female fertility. In women and some production animals, AMH is used to identify which individuals will respond best to ovarian stimulation for assisted reproductive technologies. However, few studies have evaluated AMH's predictive value in unassisted reproduction, and they have yielded conflicting results. To assess the predictive value of AMH in the context of reproductive aging, we prospectively measured serum AMH in 9-month-old Siberian hamsters shortly before breeding them. Female Siberian hamsters experience substantial declines in fertility and fecundity by 9months of age. We also measured serum AMH in 5-month-old females treated with 4-vinylcyclohexene diepoxide (VCD), which selectively destroys ovarian follicles and functionally accelerates ovarian aging. Vehicle-treated 5-month-old females served as controls. AMH concentrations were significantly reduced in VCD-treated females yet many females with low AMH reproduced successfully. On average, both young and old hamsters that littered had higher AMH concentrations than females that did not. However, some females with relatively high AMH concentrations failed to litter, whereas several with low AMH succeeded. Our results suggest that mean AMH concentration can predict mating outcomes on a population or group level, but on an individual basis, a single AMH determination is less informative.

  7. Nonphotic phase shifting in hamster clock mutants.

    PubMed

    Mrosovsky, N; Salmon, P A; Menaker, M; Ralph, M R

    1992-01-01

    Golden hamsters with the tau mutation were kept in the dark and induced to become active through confinement to a novel running wheel for 3 hr. The response of the mutants to this nonphotic phase-shifting stimulus differed from that of wild-type hamsters. The mutants showed larger phase shifts, and their phase response curves differed in shape, with an advance portion at about circadian time 24, a phase at which wild types show delays. The results establish that the tau mutation, in addition to its already known effects, alters the response of the circadian system to nonphotic events.

  8. Volatile Release From The Siberian Traps Inferred From Melt Inclusions

    NASA Astrophysics Data System (ADS)

    Black, Benjamin A.; Elkins-Tanton, Linda T.; Rowe, Michael C.; Ukstins Peate, Ingrid

    2010-05-01

    The Siberian Traps Large Igneous Province is one of the largest known continental flood volcanic provinces in the Phanerozoic. The quantification of volatile degassing is particularly important because the Siberian Traps have often been invoked as a possible trigger for the end-Permian mass extinction (e.g. Campbell et al., 1992; Wignall, 2001). Volatile degassing provides a crucial mechanism to link mafic volcanic eruption with global environmental change. Mafic flood basalt magmas are expected to have low volatile contents (similar to mid-ocean ridge basalts). However, Siberian Traps magmas were chambered in and erupted through a thick sedimentary basin and may have interacted with, and obtained volatiles from, sedimentary lithologies such as limestone, coal, and evaporite. Melt inclusions from the Siberian Traps provide insight into the potential total volatile budget throughout the evolution of the large igneous province. These droplets of trapped melt may preserve volatile species that would otherwise have degassed at the time of eruption. We present data from the analysis of more than 100 melt inclusions, including both homogenized inclusions and rare glassy inclusions with low crystallinity. Many melt inclusions from tuffs and flows near the base of the Siberian Traps sequence are substantially enriched in chlorine and fluorine compared to Deccan Traps and Laki melt inclusions (Self et al., 2008; Thordarson et al., 1996). These inclusions record chlorine concentrations up to ~1400 ppm, and fluorine concentrations up to ~5000 ppm. Olivines from the Maymechinsky suite, recognized as the last extrusive products of Siberian Traps volcanism, contain melt inclusions with maximum sulfur concentrations in the range of ~5000 ppm and substantial concentrations of chlorine. Intrusive igneous rocks from the province also display significant volatile contents. A sill from the Ust-Ilimsk region yielded plagioclase-hosted melt inclusions which contain chlorine and fluorine

  9. Volatile Release from the Siberian Traps Inferred from Melt Inclusions

    NASA Astrophysics Data System (ADS)

    Black, B. A.; Elkins-Tanton, L. T.; Rowe, M. C.; Ukstins Peate, I.

    2009-12-01

    The Siberian Traps Large Igneous Province is one of the largest known continental flood volcanic provinces in the Phanerozoic. The quantification of volatile degassing is particularly important because the Siberian Traps have often been invoked as a possible trigger for the end-Permian mass extinction (e.g. Campbell et al., 1992; Wignall, 2001). Volatile degassing provides a crucial mechanism to link mafic volcanic eruption to global environmental change. Mafic flood basalt magmas are expected to have low volatile contents (similar to mid-ocean ridge basalts). However, Siberian Traps magmas were chambered in and erupted through a thick sedimentary basin and may have interacted with, and obtained volatiles from, sedimentary lithologies such as limestone, coal, and evaporite. Melt inclusions from the Siberian Traps provide insight into the potential total volatile budget throughout the evolution of the large igneous province. These droplets of trapped melt may preserve volatile species that would otherwise have degassed at the time of eruption (Thordarson et al., 1996). Mafic pyroclastic deposits from the lowermost Arydzhangsky suite (basal Siberian Traps) contain clinopyroxene phenocrysts hosting melt inclusions. Electron microprobe analysis of clinopyroxene-hosted re-homogenized melt inclusions indicates maximum measured concentrations of up to 1500 - 2000 ppm sulfur, 500 - 760 ppm chlorine, and 1900 - 2400 ppm fluorine. Olivines from the Maymechinsky suite, recognized as the last extrusive products of Siberian Traps volcanism, contain melt inclusions with maximum sulfur concentrations in the range of 5000 ppm, and less substantial concentrations of chlorine and fluorine. Intrusive igneous rocks from the province also display significant volatile contents. A sill from the Ust-Ilimsk region yielded plagioclase-hosted melt inclusions which contain chlorine and fluorine concentrations nearing one weight percent. Visscher et al. (2004) proposed that chlorofluorocarbon

  10. 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.

  11. Increases in plasma pool size of lipoprotein components in copper-deficient hamsters

    SciTech Connect

    Al-Othman, A.A.; Rosenstein, F.; Lei, K.Y. )

    1991-03-15

    Twenty-four male Golden Syrian hamsters, were randomly assigned to 2 dietary copper (Cu) treatments; deficient and adequate. Reductions in weight gain, hematocrit and liver Cu as well as increases in heart weight and plasma volume were observed in CD hamsters after 7 weeks of treatment. Plasma very low (VLDL), low (LDL) and high (HDL) density lipoproteins were isolated by ultracentrifugation and Sepharose column chromatography. The percentage of total plasma cholesterol carried by LDL was increased from 20 to 24% but was reduced from 71 to 68% for HDL as a result of Cu deficiency. In LDL the % composition of triglycerides (TG) and phospholipids (PL) was increased by 25% but that of cholesterol was reduced by 13%. The % composition of protein was reduced 24% but that of TG was increased 18% in VLDL by Cu deficiency. Since plasma volume was increased 50% in CD hamsters, the data were expressed as the amount present in the plasma pool corrected for body weight. With the exceptions of smaller increased in VLDL protein and PL as well as the more than threefold increases in LDL TG and PL plasma pool size, the pool size for the rest of the lipoprotein components were increased about twofold in CD hamsters. The lipoprotein data further indicate that Cu deficiency increased the particle number of VLDL, LDL and HDL but enlarged the size of only VLDL and LDL.

  12. Apparent absence of alpha-2 adrenergic receptors from hamster brown adipocytes.

    PubMed

    McMahon, K K; Schimmel, R J

    1982-04-05

    The possible presence of alpha adrenergic control of lipolysis and cyclic AMP production in brown adipocytes of hamsters was studied in adipocytes isolated from interscapular, subscapular, cervical and axillary regions of normal male hamsters maintained at 25 degrees C. Lipolysis activated by either 3-isobutyl-l-methyl xanthine or isoproterenol was unaffected by the presence of the alpha adrenergic selective agonists clonidine and methoxamine. Similarly, accumulation of cyclic AMP in response to beta-receptor stimulation, alone or in combination with a methyl xanthine, was unaffected by clonidine or methoxamine. In contrast, both lipolysis and cyclic AMP accumulation in brown fat cells were effectively suppressed in the presence of nicotinic acid, prostaglandin E1 or N6-phenylisopropyl adenosine. Accumulation of cyclic AMP in response to the mixed agonist norepinephrine was not influenced when cells were exposed to the alpha adrenergic blocking drugs yohimbine or tolazoline. These observations suggest that alpha-2 adrenergic receptors which are present on hamster white fat cells and control production of cyclic AMP and lipolysis are absent from hamster brown adipocytes. On the other hand, brown fat cells of this species appear to respond to a number of other inhibitory compounds in a manner not markedly different from that of white adipocytes.

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

    PubMed Central

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

    2016-01-01

    Statement of the Problem: Oral mucositis (OM) is a common side effect of anti-cancer drugs and needs significant attention for its prevention. Purpose: This study aimed to evaluate the healing effects of olive leaf extract on 5-fluorouracil-induced OM in golden hamster. Materials and Method: 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. Results: 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). Conclusion: 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. PMID:27942549

  14. Aortic ER stress in streptozotocin-induced diabetes mellitus in APA hamsters.

    PubMed

    Kurokawa, Masaki; Hideshima, Makoto; Ishii, Yoshiyuki; Kyuwa, Shigeru; Yoshikawa, Yasuhiro

    2009-04-01

    Atherosclerosis is thought to be associated with endoplasmic reticulum (ER) dysfunction and the accumulation of unfolded proteins. In this study, we examined the relationship between atherosclerosis and ER stress and the effect of sodium 4-phenylbutyrate (4-PBA), a kind of chemical chaperone, on atherosclerosis in streptozotocin-induced diabetic APA hamsters. Male, 8-week-old, APA hamsters were injected with streptozotocin (30 mg/kg body weight) to induce diabetes mellitus, and ER stress was evaluated immunohistochemically or by semi-quantitative RT-PCR analysis using ER stress markers such as calreticulin and GPR78. Control hamsters were injected with citrate buffer and were similarly analyzed. In the aorta of control animals, a weak ER stress was detected, and 4-PBA treatment decreased the calreticulin- and GRP78-positive areas and also reduced the mRNA levels of calreticulin and GRP78. On the other hand, strong ER stress was detected at the lesser curvature of the aortic arch of streptozotocin-induced diabetic APA hamsters. However, 4-PBA treatment failed to lessen the ER stress in the aorta and had no effect on improvement of the atherosclerotic lesions. These results may provide an explanation for the complex etiology of atherosclerosis accompanied by diabetes mellitus and various other clinical phenotypes of atherosclerosis.

  15. T-lymphocyte-rich thymoma and myasthenia gravis in a Siberian tiger (Panthera tigris altaica).

    PubMed

    Allan, K; Masters, N; Rivers, S; Berry, K; Routh, A; Lamm, C

    2014-01-01

    A 10-year-old captive male Siberian tiger (Panthera tigris altaica) presented with acute onset collapse, vomiting and dyspnoea, preceded by a 6-month period of progressive muscle wasting. Following humane destruction, post-mortem examination revealed a large multilobulated mass in the cranial mediastinum, which was diagnosed as a T-lymphocyte-rich thymoma with the aid of immunohistochemistry. Retrospective serology for acetylcholine receptor antibodies (titre 3.90 nmol/l) confirmed a diagnosis of thymoma-associated myasthenia gravis. Thymomas are reported rarely in wild carnivores, but when detected they appear to be similar in morphology to those seen in domestic carnivores and may also be accompanied by paraneoplastic syndromes. The clinical signs of myasthenia gravis in the tiger were consistent with those reported in cats and dogs and the condition is proposed as an important differential diagnosis for generalized weakness in captive Felidae. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. Clinical course of a malignant peripheral nerve sheath tumor in a Siberian tiger (Panthera tigris altaica).

    PubMed

    Steinmetz, Hanspeter W; Rütten, Maja; Ruess-Melzer, Katja; Ohlerth, Stefanie; Lischer, Christoph; Oevermann, Anna; Bode-Lesniewska, Beata; Hatt, Jean-Michel

    2010-11-01

    A 14-year-old male Siberian tiger (Panthera tigris altaica) was admitted with an ulcerating mass on the right thoracic wall. Radiographic and computed tomographic evaluation indicated 2 isolated cutaneous masses without any signs of metastasis. Histology of a Tru-Cut biopsy revealed an anaplastic sarcoma with giant cells. Both tumors were resected with appropriate normal tissue margins. The size of the defect did not allow primary closure of the wound; therefore, a mesh expansion technique was attempted. Three months later, the tiger had to be euthanized due to extensive metastasis to the lungs. Histomorphological features and immunohistochemical results confirmed the diagnosis of malignant peripheral nerve sheath tumor. In contrast to domestic animal experience, the tumor had spread extensively to the lungs without local reccurrence in a short period of time. Correct diagnosis requires various immunohistochemical evaluations of the tumor tissue.

  17. Thyroid function and cold acclimation in the hamster, Mesocricetus auratus

    SciTech Connect

    Tomasi, T.E.; Horwitz, B.A.

    1987-02-01

    Basal metabolic rate (BMR), thyroxine utilization rate (T4U), and triiodothyronine utilization rate (T3U) were measured in cold-acclimated (CA) and room temperature-acclimated (RA) male golden hamsters, Mesocricetus auratus. Hormone utilization rates were calculated via the plasma disappearance technique using SVI-labeled hormones and measuring serum hormone levels via radioimmunoassay. BMR showed a significant 28% increase with cold acclimation. The same cold exposure also produced a 32% increase in T4U, and a 204% increase in T3U. The much greater increase in T3U implies that previous assessments of the relationship between cold acclimation and thyroid function may have been underestimated and that cold exposure induces both quantitative and qualitative changes in thyroid function. It is concluded that in the cold-acclimated state, T3U more accurately reflects thyroid function than does T4U. A mechanism for the cold-induced change in BMR is proposed.

  18. Disparities in activity levels and learning ability between Djungarian hamster (Phodopus sungorus) and Roborovskii hamster (Phodopus roborovskii).

    PubMed

    Ikeda, Hiromi; Nagasawa, Mao; Yamaguchi, Takeshi; Minaminaka, Kimie; Goda, Ryosei; Chowdhury, Vishwajit S; Yasuo, Shinobu; Furuse, Mitsuhiro

    2017-03-01

    The Djungarian hamster and the Roborovskii hamster belong to the same genus of Phodopus. However, the Djungarian hamster is tame and shows sedative behavior, while Roborovskii hamster is not tame and shows high levels of locomotor activity. Hyperactivity occurs in animals with tameless behavior. Tameness or tamelessness behavior is very important because tameness helps for breeding and controlling as well as it enables a strong human-animal bond. In the present study, we examined the relationships between activity levels and cognitive function in Djungarian and Roborovskii hamsters. Three types of behavioral tests were performed to analyze their activity levels, memory and leaning ability. The levels of L- and D-amino acids and monoamines in the brain were then determined. Roborovskii hamsters showed significantly higher locomotor activity than Djungarian hamsters. Memory ability was not significantly different between the two hamsters, but Roborovskii hamsters showed lower learning ability. Brain levels of D-serine which is related to enhancement in memory and learning ability, were significantly higher in Djungarian hamsters, but the reverse was true for brain dopamine and serotonin levels. These results suggest that these differences in brain metabolism may be related to the behavioral differences between the two hamsters.

  19. Lifetime carcinogenesis studies of chrysotile asbestos (CAS No. 12001-29-5) in syrian golden hamsters (feed studies). Technical report series

    SciTech Connect

    Not Available

    1990-07-01

    Carcinogenesis studies of short range (SR), intermediate range (IR) or intermediate range chrysotile asbestos in combination with the intestinal carcinogen 1,2-dimethylhydrazine dihydrochloride (DMH) were conducted with male and female Syrian golden hamsters. Both forms of chrysotile asbestos were administered at a concentration of 1% in pelleted diet for the entire lifetime of the hamsters, starting with mothers of the test animals. Group sizes varied from 125 to 253. Starting at 6 weeks of age, male and female hamsters in the intermediate range chrysotile/DMH study were given oral doses of DMH (4 mg/kg) every other week for a total of 5 doses. There was no adverse effect on body weight gain or survival by either form of asbestos or by asbestos in combination with DMH. Under the conditions of these studies, neither short range chrysotile nor intermediate range chrysotile asbestos was carcinogenic when ingested at 1% levels in the diet by male and female Syrian golden hamsters. While there were increases in the rates of adrenal cortical adenomas in male and female hamsters exposed to intermediate range chrysotile asbestos compared with pooled control groups, these incidence rates were not different when compared with the concurrent control groups. Additionally, the biologic importance of adrenal tumors in the absence of target organ (gastrointestinal tract) neoplasia is questionable.

  20. Cutaneous Leishmaniasis in the Dorsal Skin of Hamsters: a Useful Model for the Screening of Antileishmanial Drugs

    PubMed Central

    Robledo, Sara M.; Carrillo, Lina M.; Daza, Alejandro; Restrepo, Adriana M.; Muñoz, Diana L.; Tobón, Jairo; Murillo, Javier D.; López, Anderson; Ríos, Carolina; Mesa, Carol V.; Upegui, Yulieth A.; Valencia-Tobón, Alejandro; Mondragón-Shem, Karina; RodrÍguez, Berardo; Vélez, Iván D.

    2012-01-01

    Traditionally, hamsters are experimentally inoculated in the snout or the footpad. However in these sites an ulcer not always occurs, measurement of lesion size is a hard procedure and animals show difficulty to eat, breathe and move because of the lesion. In order to optimize the hamster model for cutaneous leishmaniasis, young adult male and female golden hamsters (Mesocricetus auratus) were injected intradermally at the dorsal skin with 1 to 1.5 x l07 promastigotes of Leishmania species and progression of subsequent lesions were evaluated for up to 16 weeks post infection. The golden hamster was selected because it is considered the adequate bio-model to evaluate drugs against Leishmania as they are susceptible to infection by different species. Cutaneous infection of hamsters results in chronic but controlled lesions, and a clinical evolution with signs similar to those observed in humans. Therefore, the establishment of the extent of infection by measuring the size of the lesion according to the area of indurations and ulcers is feasible. This approach has proven its versatility and easy management during inoculation, follow up and characterization of typical lesions (ulcers), application of treatments through different ways and obtaining of clinical samples after different treatments. By using this method the quality of animal life regarding locomotion, search for food and water, play and social activities is also preserved. PMID:22546739

  1. Tissue distribution of indium after repeated intratracheal instillations of indium-tin oxide into the lungs of hamsters.

    PubMed

    Tanaka, Akiyo; Hirata, Miyuki; Matsumura, Nagisa; Kiyohara, Yutaka

    2015-01-01

    The aim of this study was to analyze the tissue distribution of indium after intratracheally instilling indium-tin oxide (ITO) into the lungs of hamsters. Male Syrian hamsters received an intratracheal dose of 3 mg/kg or 6 mg/kg of ITO particles containing 2.2 mg/kg or 4.5 mg/kg of indium, twice weekly for 8 weeks. In parallel, control hamsters received only an intratracheal dose of distilled water. A subset of hamsters was euthanized periodically throughout the study from 8 up to 78 weeks after the final instillation. The distribution of indium in the lungs, liver, kidneys and spleen, as well as pathological changes in the liver, kidneys, and spleen, was determined. The contents of indium in the lungs in the two ITO groups gradually decreased over the 78-week observation period, with elimination half-lives of approximately 142 weeks for the 3 mg/kg ITO group and 124 weeks for the 6 mg/kg ITO. The indium concentrations in the liver, kidneys, and spleen gradually increased throughout the observation period. Although foci of the lesions were observed histopathologically in the extrapulmonary organs among the two ITO groups, the control group showed similar lesions. The results clearly demonstrate that the clearance of indium from the body is extremely slow after intratracheal instillation in hamsters.

  2. Hypolipidemic and antioxidative effects of noni (Morinda citrifolia L.) juice on high- fat/cholesterol-dietary hamsters.

    PubMed

    Lin, Yi-Ling; Chou, Chung-Hsi; Yang, Deng-Jye; Chen, Jr-Wei; Tzang, Bor-Show; Chen, Yi-Chen

    2012-09-01

    Noni juice (NJ) is rich in phytochemicals and polysaccharides. Lipid-lowering and antioxidative effects of NJ were investigated in this study. Fifty male hamsters were assigned randomly to one of the following groups: (1) normal diet and distilled water (LFCD); (2) high-fat/cholesterol diet and distilled water (HFCD); (3) HFCD and 3 ml NJ (including 0.20 g solids)/kg BW (NJ_L); (4) HFCD and 6 mL NJ (including 0.40 g solids)/kg BW (NJ_M); (5) HFCD and 9 ml NJ (including 0.60 g solids)/kg BW (NJ_H) for six weeks. NJ supplementation decreased (p < 0.05) serum triacylglycerol, cholesterol, atherogenic index, malondialdehyde levels, and hepatic lipids in HFCD hamsters, whereas serum trolox equivalent antioxidant capacity, glutathione, and fecal lipids in HFCD hamsters were increased (p < 0.05) by NJ supplementation. Although NJ supplementation downregulated (p < 0.05) sterol regulator element binding protein-1c in HFCD hamsters, it upregulated (p < 0.05) hepatic peroxisome proliferator-activated receptor-alpha and uncoupling protein 2 gene expressions in HFCD hamsters. Results demonstrate that NJ promotes cardioprotection in a high-fat/cholesterol diet.

  3. Pathology of acute inhalation exposure to 3-methylfuran in the rat and hamster

    SciTech Connect

    Haschek, W.M.; Morse, C.C.; Boyd, M.R.; Hakkinen, P.J.; Witschi, H.P.

    1983-12-01

    The acute inhalation toxicity of 3-methylfuran (3MF) was investigated in SPF Fischer-derived and CD/CR rats, and golden Syrian hamsters by determination of the 2-week LC50, and by histologic examination of animals killed 1, 3, and 14 days following a 1-hr exposure to 148 and 322 mumole 3MF/liter for CD/CR rats and hamsters, respectively. The Fischer-derived rat was more sensitive to 3MF-induced lethality than the CD/CR rat with an LC50 in the male rat of 81 mumole/liter-1 hr as compared to 222 mumole/liter-1 hr. No sex difference was found. The hamster was relatively resistant with no lethality at 322 mumole 3MF/liter-2 hr. Pulmonary damage was present in both species. In the hamster, selective necrosis of nonciliated bronchiolar epithelial (Clara) cells was seen at 1 day with virtually complete regeneration by 14 days whereas in the rat the bronchiolar epithelial damage was more extensive and was followed by scattered peribronchiolar fibrosis and epithelial mucous metaplasia suggestive of ''small airway disease'' of man. Relatively selective 3MF-induced necrosis of olfactory epithelium occurred in the nasal mucosa of both species. Resolution of this lesion was seen by 14 days in the hamster. In the rat, however, the necrosis was much more extensive and was followed by partially occlusive fibrosis of the nasal cavity as seen at 14 days. 3MF also induced centrilobular hepatic necrosis in both species. In the rat, lymphocyte necrosis in the thymus and spleen, and esophageal necrosis was also seen.

  4. Pathology of acute inhalation exposure to 3-methylfuran in the rat and hamster

    SciTech Connect

    Haschek, W.M.; Morse, C.C.; Boyd, M.R.; Hakkinen, P.J.; Witschi, H.P.

    1983-01-01

    The acute inhalation toxicity of 3-methylfuran (3MF) was investigated in SPF Fischer-derived and CD/CR rats, and golden Syrian hamsters by determination of the 2-week LC/sub 50/, and by histologic examination of animals killed 1, 3, and 14 days following a 1-hr exposure to 148 and 322 ..mu..mole 3MF/liter for CD/CR rats and hamsters, respectively. The Fischer-derived rat was more sensitive to 3MF-induced lethality than the CD/CR rat with an LC/sub 50/ in the male rat of 81 ..mu..mole/liter-1 hr as compared to 222 ..mu..mole/liter-1hr. No sex difference was found. The hamster was relatively resistant with no lethality at 322 ..mu..mole 3MF/liter-2 hr. Pulmonary damage was present in both species. In the hamster, selective necrosis of nonciliated bronchiolar epithelial (Clara) cells was seen at 1 day with virtually complete regeneration by 14 days whereas in the rat the bronchiolar epithelial damage was more extensive and was followed by scattered peribronchiolar fibrosis and epithelial mucous metaplasia suggestive of ''small airway disease'' of man. Relatively selective 3MF-induced necrosis of olfactory epithelium occurred in the nasal mucosa of both species. Resolution of this lesion was seen by 14 days in the hamster. In the rat, however, the necrosis was much more extensive and was followed by partially occlusive fibrosis of the nasal cavity as seen at 14 days. 3MF also induced centrilobular hepatic necrosis in both species. In the rat, lymphocyte necrosis in the thymus and spleen, and esophageal necrosis was also seen.

  5. Reduction in cholesterol absorption is enhanced by stearate-enriched plant sterol esters in hamsters.

    PubMed

    Rasmussen, Heather E; Guderian, David M; Wray, Curtis A; Dussault, Patrick H; Schlegel, Vicki L; Carr, Timothy P

    2006-11-01

    Consumption of plant sterol esters reduces plasma LDL cholesterol concentration by inhibiting intestinal cholesterol absorption. Commercially available plant sterol esters are prepared by esterifying free sterols to fatty acids from edible plant oils such as canola, soybean, and sunflower. To determine the influence of the fatty acid moiety on cholesterol metabolism, plant sterol esters were made with fatty acids from soybean oil (SO), beef tallow (BT), or purified stearic acid (SA) and fed to male hamsters for 4 wk. A control group fed no plant sterol esters was also included. Hamsters fed BT and SA had significantly lower cholesterol absorption and decreased concentrations of plasma non-HDL cholesterol and liver esterified cholesterol, and significantly greater fecal sterol excretion than SO and control hamsters. Cholesterol absorption was lowest in hamsters fed SA (7.5%), whereas it was 72.9% in control hamsters. Cholesterol absorption was correlated with fecal sterol excretion (r = -0.72, P < 0.001), liver cholesterol concentration (r = 0.88, P < 0.001), and plasma non-HDL cholesterol concentration (r = 0.85, P < 0.001). A multiple regression model that included each sterol ester type vs. cholesterol absorption indicated that intake of steryl stearate was the only dietary component that contributed significantly to the model (R2 = -0.75, P < 0.001). Therefore, our results demonstrate that BT and SA are more effective than SO in reducing cholesterol absorption, liver cholesterol, and plasma non-HDL cholesterol concentration, suggesting that cardioprotective benefits can be achieved by consuming stearate-enriched plant sterol esters.

  6. Expression and phylogeny of candidate genes for sex differentiation in a primitive fish species, the Siberian sturgeon, Acipenser baerii.

    PubMed

    Berbejillo, Julio; Martinez-Bengochea, Anabel; Bedo, Gabriela; Brunet, Frédéric; Volff, Jean-Nicolas; Vizziano-Cantonnet, Denise

    2012-08-01

    The molecular mechanisms underlying testis differentiation in basal actinopterygian fish remains poorly understood. The sex differentiation period was investigated in the Siberian sturgeon, Acipenser baerii, by expression profiling of Sertoli cell transcription factors (dmrt1, sox9) that control testis differentiation in vertebrates; Leydig cell factors (cyp17a1, star) affecting androgen production; the androgen receptor (ar); a growth factor controlling testis development (igf1); and a gene coding for a gonadotropin hormone (lh). Two genes were characterised for the first time in the Siberian sturgeon (dmrt1, cyp17a1), while the others came from public databases. Sturgeon gonad development is very slow, with a late sexual differentiation time during their juvenile stage, and are still immature at 3 years of age. Immature fish showed a sex-dimorphic pattern; all the genes studied displayed a higher expression level in male gonads. We took advantage of the presence of juvenile fish with pre- and post-differentiated gonads (16 and 18 months old) to characterise them at the molecular level. The post-differentiated fish displayed a sex dimorphism of gene expression in their gonads for all genes studied, with the exception of sox9. The trends in undifferentiated fish lead us to propose that sturgeons undergoing male differentiation express high levels of Sertoli cell factors (dmrt1, sox9) and of genes involved in the production and receptivity of androgens (cyp17a1, star and ar) together with lh. Expression profiles and phylogenetic studies suggest that these genes are potential regulators of testis development in the Siberian sturgeon.

  7. Ovarian activity and pregnancy in the Siberian tiger, Panthera tigris altaica, assessed by fecal gonadal steroid hormones analyses.

    PubMed

    Putranto, Heri Dwi; Kusuda, Satoshi; Inagaki, Kayo; Kumagai, Gaku; Ishii-Tamura, Rie; Uziie, Yoko; Doi, Osamu

    2007-05-01

    Feces were collected from two female and one male Siberian tigers, Panthera tigris altaica. Steroid hormones were extracted from lyophilized feces and quantified by enzyme immunoassay. The fecal contents of estradiol-17beta (E(2)) and testosterone in the females and male, respectively, changed markedly throughout the year. The fecal E(2) contents of females Nos. 179 and 238 increased at 26.4 +/- 8.0 and 28.0 +/- 14.2 day intervals, respectively. However, the fecal contents of progesterone (P(4)) in the female kept alone did not change. In contrast, the other female, which was kept with a male, had increased fecal P(4) contents after copulation. The fecal progesterone levels of the pregnant female remained high during her 106-day pregnancy.

  8. Hydrological modelling for siberian crane Grus Leucogeranus stopover sites in northeast China.

    PubMed

    Jiang, Haibo; He, Chunguang; Sheng, Lianxi; Tang, Zhanhui; Wen, Yang; Yan, Tingting; Zou, Changlin

    2015-01-01

    Habitat loss is one of the key factors underlying the decline of many waterbird species, including Siberian Crane (Grus leucogeranus), a threatened species worldwide. Wetlands are the primary stopover for many waterbirds and restoration of these wetlands involves both hydrological restoration and water resource management. To protect the stopover sites of Siberian Cranes, we collected Siberian Crane stopover numbers, meteorological and hydrological data, and remote sensing data from 2008 to 2011 in Momoge National Nature Reserve, one of the largest wetlands in northeastern China. A model was developed to estimate the suitability of Siberian Crane stopover sites. According to our results, the most suitable daily water level for Siberian Cranes between 2008 and 2012 occurred in the spring of 2008 and in the Scirpus planiculmis growing season and autumn of 2010. We suggest a season-dependent water management strategy in order to provide suitable conditions at Siberian Crane stopover sites.

  9. Hydrological Modelling for Siberian Crane Grus Leucogeranus Stopover Sites in Northeast China

    PubMed Central

    Jiang, Haibo; He, Chunguang; Sheng, Lianxi; Tang, Zhanhui; Wen, Yang; Yan, Tingting; Zou, Changlin

    2015-01-01

    Habitat loss is one of the key factors underlying the decline of many waterbird species, including Siberian Crane (Grus leucogeranus), a threatened species worldwide. Wetlands are the primary stopover for many waterbirds and restoration of these wetlands involves both hydrological restoration and water resource management. To protect the stopover sites of Siberian Cranes, we collected Siberian Crane stopover numbers, meteorological and hydrological data, and remote sensing data from 2008 to 2011 in Momoge National Nature Reserve, one of the largest wetlands in northeastern China. A model was developed to estimate the suitability of Siberian Crane stopover sites. According to our results, the most suitable daily water level for Siberian Cranes between 2008 and 2012 occurred in the spring of 2008 and in the Scirpus planiculmis growing season and autumn of 2010. We suggest a season-dependent water management strategy in order to provide suitable conditions at Siberian Crane stopover sites. PMID:25874552

  10. Effects of aging on sleep in the golden hamster.

    PubMed

    Naylor, E; Buxton, O M; Bergmann, B M; Easton, A; Zee, P C; Turek, F W

    1998-11-01

    The golden hamster (Mesocricetus auratus) has been a model organism for the study of circadian rhythmicity and, in particular, the effects of age on the circadian system. Surprisingly, nothing is known about the effects of advanced age on sleep in this species. As a first step in determining the effects of aging on sleep in the golden hamster, we recorded sleep for 24 hours in 12 young (3 months) and 18 old (17-18 months) golden hamsters entrained to a 14:10 light:dark (LD) cycle. Aged hamsters exhibited small but significant increases in overall NREM sleep time, primarily due to an increase in time the old animals spent in the NREM sleep state during the dark period relative to the young hamsters. There were no significant differences in REM sleep, median sleep episode length, or the number of arousals. The most striking differences between the sleep of young and old hamsters was in NREM delta (0.5-4 Hz) power per epoch. Old hamsters showed approximately 27% less (p=0.0004) delta power per NREM epoch than young hamsters. It is possible that increased NREM sleep time in the old hamsters may be a failed attempt to maintain cumulative delta power; ie, old hamsters may have more NREM sleep in order to make up for the lower intensity of their sleep. This decline in delta power with age parallels earlier findings in cats and humans, although has it not been previously reported in rodents.

  11. SPOT-VEG Based Analysis of Siberian Silkmoth Outbreak

    NASA Technical Reports Server (NTRS)

    Kharuk, Viatcheslav I.; Ranson, K. Jon; Im. Sergey T.

    2007-01-01

    The spatial and temporal dynamics of an outbreak of the Siberian silkmoth were correlated with topographic features of the affected area using SPOT-VEG data and a high resolution digital elevation model (DEM). In 2002-2003 an outbreak affected approximately 20,000 ha in the South Siberian mountains of Russia. The outbreak began between the elevations of approximately 430- 480 m and on southwest slopes with steepness < 5 degrees. As the pest searched for food it moved up and down slope, resulting in an elevation distribution split within a range of approximately 390-540 m and slope steepness up to 15 degrees. In the final phase the azimuth distribution of damaged stands became even. The correlation between the initial phase and topographic features can be used to prioritize monitoring forest areas most vulnerable to destruction by pests.

  12. Overcoming Depolarizing Resonances with Dual Helical Partial Siberian Snakes

    SciTech Connect

    Huang, H.; Ahrens, L. A.; Bai, M.; Brown, K.; Courant, E. D.; Gardner, C.; Glenn, J. W.; Luccio, A. U.; MacKay, W. W.; Okamura, M.; Ptitsyn, V.; Roser, T.; Tepikian, S.; Tsoupas, N.; Zelenski, A.; Zeno, K.; Lin, F.; Takano, J.

    2007-10-12

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is challenging. In a medium energy accelerator, the depolarizing spin resonances are strong enough to cause significant polarization loss but full Siberian snakes cause intolerably large orbit excursions and are also not feasible since straight sections usually are too short. Recently, two helical partial Siberian snakes with double pitch design have been installed in the Brookhaven Alternating Gradient Synchrotron (AGS). With a careful setup of optics at injection and along the energy ramp, this combination can eliminate the intrinsic and imperfection depolarizing resonances otherwise encountered during acceleration to maintain a high intensity polarized beam in medium energy synchrotrons. The observation of partial snake resonances of higher than second order will also be described.

  13. Overcoming Depolarizing Resonances with Dual Helical Partial Siberian Snakes

    NASA Astrophysics Data System (ADS)

    Huang, H.; Ahrens, L. A.; Bai, M.; Brown, K.; Courant, E. D.; Gardner, C.; Glenn, J. W.; Lin, F.; Luccio, A. U.; Mackay, W. W.; Okamura, M.; Ptitsyn, V.; Roser, T.; Takano, J.; Tepikian, S.; Tsoupas, N.; Zelenski, A.; Zeno, K.

    2007-10-01

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is challenging. In a medium energy accelerator, the depolarizing spin resonances are strong enough to cause significant polarization loss but full Siberian snakes cause intolerably large orbit excursions and are also not feasible since straight sections usually are too short. Recently, two helical partial Siberian snakes with double pitch design have been installed in the Brookhaven Alternating Gradient Synchrotron (AGS). With a careful setup of optics at injection and along the energy ramp, this combination can eliminate the intrinsic and imperfection depolarizing resonances otherwise encountered during acceleration to maintain a high intensity polarized beam in medium energy synchrotrons. The observation of partial snake resonances of higher than second order will also be described.

  14. Overcoming depolarizing resonances with dual helical partial Siberian snakes.

    PubMed

    Huang, H; Ahrens, L A; Bai, M; Brown, K; Courant, E D; Gardner, C; Glenn, J W; Lin, F; Luccio, A U; Mackay, W W; Okamura, M; Ptitsyn, V; Roser, T; Takano, J; Tepikian, S; Tsoupas, N; Zelenski, A; Zeno, K

    2007-10-12

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is challenging. In a medium energy accelerator, the depolarizing spin resonances are strong enough to cause significant polarization loss but full Siberian snakes cause intolerably large orbit excursions and are also not feasible since straight sections usually are too short. Recently, two helical partial Siberian snakes with double pitch design have been installed in the Brookhaven Alternating Gradient Synchrotron (AGS). With a careful setup of optics at injection and along the energy ramp, this combination can eliminate the intrinsic and imperfection depolarizing resonances otherwise encountered during acceleration to maintain a high intensity polarized beam in medium energy synchrotrons. The observation of partial snake resonances of higher than second order will also be described.

  15. Middle Paleozoic kimberlite magmatism in the northeastern Siberian craton

    NASA Astrophysics Data System (ADS)

    Egorova, E. O.; Afanas'ev, V. P.; Pokhilenko, N. P.

    2016-10-01

    The mineral chemistry and crystal morphology of kimberlite pyropes from the Billyakh River placer in the northeastern Siberian craton are characterised in terms of the placer history. The pyropes bear signatures of chemical weathering (dissolution), presumably in a Middle Paleozoic laterite profile, and therefore were originally hosted by Middle Paleozoic kimberlites. The broad occurrence of placer pyropes with lateritic dissolution signatures points to the presence of Middle Paleozoic diamond-bearing kimberlites in the study area.

  16. ACCELERATING AND COLLIDING POLARIZED PROTONS IN RHIC WITH SIBERIAN SNAKES.

    SciTech Connect

    ROSER,T.; AHRENS,L.; ALESSI,J.; BAI,M.; BEEBE - WANG,J.; BRENNAN,J.M.; BROWN,K.A.; BUNCE,G.; CAMERON,P.; COURANT,E.D.; DREES,A.; FISCHER,W.; ET AL

    2002-06-02

    We successfully injected polarized protons in both RHIC rings and maintained polarization during acceleration up to 100 GeV per ring using two Siberian snakes in each ring. Each snake consists of four helical superconducting dipoles which rotate the polarization by 180{sup o} about a horizontal axis. This is the first time that polarized protons have been accelerated to 100 GeV. We report on our experiences during commissioning and operation of collider with polarized protons.

  17. Vertical plate motions in the West Siberian Basin

    NASA Astrophysics Data System (ADS)

    Vibe, Yulia

    2014-05-01

    The West Siberian Basin is a sedimentary basin situated between the Ural Mountains and the Siberian Craton. The Basin has experienced several periods of subsidence and uplift since the arrival of the Siberian Traps c. 250 Ma. Although the Basin is extensively explored and hosts large reserves of Oil and Gas, the forces driving the vertical motions are poorly understood. In this work we attempt to analyse the amount, timing and location of subsidence and uplift in the Basin to shed light on the possible causes of these motions. A detailed description of sedimentary layers is published in a number of Soviet-era books and articles and serves as a basis for our research. This data is first converted into sediment grids through time. Subsequently, the sediments, the sediment load and the compaction are taken into account ('backstripping') to produce the depth of the Basin at respective time steps. With this technique we calculate the tectonic component of subsidence. Uncertainties related to uplift events are estimated by the unconformities in the stratigraphic charts. One of the possible driving forces of vertical motions is a change of force balance arising at plate boundaries. Since active plate tectonics have been absent from West Siberia since the formation of the Urengoy and Khodosey Rifts, c. 250Ma, we study the far-field tectonic effects as a potential driving mechanism. Indeed, some of the significant vertical events in the West Siberian Basin coincide with the major tectonic events around Siberia. An example is the spreading in the Arctic (Eurasian Basin) in the Eocene (56 Ma) which was synchronous with initiation of uplift events in the northern part of West Siberia. In the middle Oligocene (33 Ma), the northern and eastern parts of the basin were subjected to uplift as subsidence migrated southwards and the Basin rose above the sea level. This was coincident with the changes of plate motions in the northern North Atlantic and Indo-European collision.

  18. Helical dipole partial Siberian snake for the AGS

    NASA Astrophysics Data System (ADS)

    Takano, J.; Ahrens, L. A.; Alforque, R.; Bai, M.; Brown, K.; Courant, E. D.; Ganetis, G.; Gardner, C. J.; Glenn, J. W.; Hattori, T.; Huang, H.; Jain, A.; Luccio, A. U.; MacKay, W. W.; Okamura, M.; Roser, T.; Tsoupas, N.; Tepikian, S.; Tuozzolo, J.; Wood, J.; Zelenski, A.; Zeno, K.

    2006-11-01

    Overcoming depolarization resonances in medium class synchrotrons (3 to 50 GeV) is one of the key issues in accelerating a highly polarized proton beam up to very high energies. Since such synchrotrons, including the Alternating Gradient Synchrotron (AGS) and the J-PARC Main Ring, generally do not have sufficiently long straight sections to accommodate full Siberian snakes with reasonable beam excursions, the practical solution is to use partial Siberian snakes that rotate the particle spin about a horizontal axis by a fraction of 180 degrees. For the AGS, we designed and installed a new partial Siberian snake consisting of a helical dipole magnet with a double pitch structure. The helical structure reduced the amount of transverse coupling as compared to that achieved by the previous solenoidal partial snake. This coupling led to partial depolarization at certain energies from horizontal betatron oscillations. The helical magnetic field in the snake magnet was calculated using a 3D magnetic field code TOSCA, and was optimized by segmenting the helical pitch and varying the lengths of the segments. Fabrication errors were checked and verified to be within required tolerances. Finally, the transverse field was measured by rotating harmonic coils. After installation, we achieved a 37.5% improvement in polarization - from 40% with the old solenoid to 55% with the new helical snake, thereby demonstrating that the helical partial snake is an effective device to suppress depolarization resonances in medium-sized synchrotrons.

  19. Acute hematologic, hepatologic, and nephrologic changes after intraperitoneal injections of 18 nm gold nanoparticles in hamsters

    PubMed Central

    Saleh, Hazem Mohamed; Soliman, Omar A; Elshazly, Mohamed Osama; Raafat, Alaa; Gohar, Adel K; Salaheldin, Taher A

    2016-01-01

    In vivo responses to gold nanoparticles (GNPs) vary not only according to the size, shape, surface charge, and capping agent of GNPs but also according to the animal model, the route of administration, and the exposure frequency and duration. We illustrate here the changes in some hematologic parameters, in the hepatic and renal functions, and in the histopathology of solid organs after multiple intraperitoneal injections of 18 nm GNPs in adult male Syrian golden hamsters. We scored the histopathological changes in the liver and kidneys to grade the deleterious effects. Multiple intraperitoneal injections of 18 nm GNPs in hamsters were nonlethal in the short term but resulted in macrocytosis and hypochromasia, leukocytosis, neutrophilia, lymphocytosis, and monocytosis. The hepatic and renal functions showed nonsignificant changes; however, histopathological examination showed hepatic and renal alterations ranging from mild to marked degeneration, with occasional necrosis of hepatocytes and tubular epithelium. PMID:27354788

  20. Photoperiod regulates the differential expression of KiSS-1 and GPR54 in various tissues and sexes of striped hamster.

    PubMed

    Li, S N; Xue, H L; Zhang, Q; Xu, J H; Wang, S; Chen, L; Xu, L X

    2015-10-30

    In order to investigate how photoperiod affects the expression of KiSS-1/G-protein-coupled receptor 54 (GPR54), the hypothalamus, the ovaries and testicles of the striped hamster were studied following photoperiod treatment and melatonin injection. We found that the melatonin concentration in the blood of the striped hamster was consistent with the treated photoperiods and that the photoperiod had significant effects on KiSS-1 expression, but the effect of photoperiod on GPR54 expression differed among tissues and sexes. The relative expression of KiSS-1 in the gonads of the male and female striped hamster was significantly higher than that in the hypothalamus, while the difference in GPR54 between the gonads and hypothalamus was inconsistent between the male and female striped hamster. In the striped hamster injected with melatonin, the expression level of KiSS-1 in the gonads and hypothalamus of the male and female striped hamster was significantly decreased; the expression level of GnRH in the gonads was also significantly decreased; the expression of GPR54 in the hypothalamus was increased. In the hypothalamus, a significant positive correlation existed between KiSS-1 and GnRH expression, while a negative correlation was observed between GPR54 and GnRH expression. These results suggest that the photoperiod-melatonin-KiSS-1-GnRH pathway plays an important role in the seasonal reproduction mechanism of the striped hamster. Additionally, photoperiod or melatonin may not be a direct regulatory factor of GPR54 expression.

  1. Intersex gonad differentiation in cultured Russian (Acipenser gueldenstaedtii) and Siberian (Acipenser baerii) sturgeon.

    PubMed

    Rzepkowska, Malgorzata; Ostaszewska, Teresa; Gibala, Monika; Roszko, Marek Lukasz

    2014-02-01

    Among sturgeons, the occurrence of individuals with gonads containing both testis and ovary components is considered pathological, and such fish are described as intersex individuals or intersexes. Intersexes are observed in both wild and cultured populations of sturgeon, usually at low frequencies. In the present study, intersex Russian (Acipenser gueldenstaedtii) and Siberian (Acipenser baerii) sturgeons constituted 30% of the studied populations. Macroscopically, intersex gonads were recognizable from 500 days posthatching (dph). Initially, gonads with predominantly male characteristics (testis-ova) were observed, but in older fish gonads with predominantly female traits (ova-testis) were more frequent. Using microscopic analysis, intersex gonads were discernible by 130-200 dph. Observations of intersex germinal epithelium development and analysis of sex distribution in the study populations indicated that feminization was occurring. Histological analysis revealed that differentiation of the germinal epithelium in such gonads was accompanied by various morphological alterations (transformations) that were described using quantitative and localization criteria. The most common type of transformations, massive subepithelial transformations, was manifested by the presence of abundant female germinal tissue located under the gonad surface epithelium in the developing testis. These transformations were identified in the early development stage (100-200 dph). In this type of transformation, differentiation of female germinal tissue at the gonad surface and male tissue at the mesorchium/mesovarium resulted in complete formation of both male and female germinal epithelia within the same gonad.

  2. Microcirculatory effects of zinc on fructose-fed hamsters.

    PubMed

    Castiglione, R C; Barros, C M M R; Boa, B C S; Bouskela, E

    2016-04-01

    Fructose is a major dietary component directly related to vascular dysfunction and diseases such as obesity, diabetes, and hypertension. Zinc is considered a non-pharmacological alternative for treating diabetes due to its antioxidant and hyperglycemia-lowering effects in diabetic animals. Therefore, the aim of this study was to evaluate the effects of dietary zinc supplementation on the microcirculatory parameters of fructose-fed hamsters. Male hamsters (Mesocricetus auratus) were fed drinking water substituted by 10% fructose solution for 60 days, whereas control animals were fed drinking water alone. Their microcirculatory function was evaluated using cheek pouch preparation, as well as their blood glucose and serum insulin levels. Their microcirculatory responses to acetylcholine (ACh, an endothelium-dependent vasodilator) and to sodium nitroprusside (SNP, an endothelium-independent vasodilator) as well as the increase in macromolecular permeability induced by 30 min of ischemia/reperfusion (I/R) were noted. Endothelium-dependent vasodilation was significantly increased in control animals with high zinc supplementation compared to the groups without zinc supplementation. Zinc was able to protect against plasma leakage induced by I/R in all control and fructose-fed groups, although the microvascular permeability was higher in animals fed drinking water substituted by 10% fructose solution compared to those fed filtered drinking water alone. Our results indicate that dietary zinc supplementation can improve microvascular dysfunction by increasing endothelial-dependent dilatation and reducing the increase in macromolecular permeability induced by I/R in fructose-fed animals. Copyright © 2015 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

  3. The hypocholesterolemic and antiatherogenic effects of Cholazol H, a chemically functionalized insoluble fiber with bile acid sequestrant properties in hamsters.

    PubMed

    Wilson, T A; Romano, C; Liang, J; Nicolosi, R J

    1998-08-01

    Cholazol H (Alpha-Beta Technology, Worcester, MA), a chemically functionalized, insoluble dietary fiber with bile acid sequestrant properties, was studied in 30 male F1 B Golden Syrian hamsters for its effect on plasma lipid concentrations and early atherogenesis in experiment 1. In experiment 2, 30 male Golden Syrian hamsters were studied for the effects on plasma lipids and fecal excretion of bile acids. In experiment 1, three groups of 10 hamsters each were fed a chow-based hypercholesterolemic diet supplemented with 5% coconut oil and 0.1% cholesterol for 6 weeks. After 6 weeks, hamsters were continued on the diet with either 0% drug (hypercholesterolemic diet [HCD]), 0.5% cholestyramine (CSTY), or 0.5% Cholazol H for 8 weeks. Fasting plasma lipids were measured at weeks 6, 10, and 14, and early atherosclerosis (fatty streak formation) was measured at week 14. Relative to HCD, CSTY and Cholazol H significantly lowered plasma total cholesterol (TC) (-37%, P < .03, and -30%, P < .04, respectively) and plasma very-low and low-density lipoprotein-cholesterol (nonHDL-C) (-45%, P < .02, and -36%, P < .03, respectively) with no significant effects on plasma HDL-C or triglycerides (TG). Despite similar reductions in nonHDL-C, only Cholazol H significantly prevented early atherosclerosis (-38%, P < .02) relative to HCD. In experiment 2, three groups of 10 hamsters each were fed a chow-based hypercholesterolemic diet supplemented with 10% coconut oil and 0.05% cholesterol and either 0% drug HCD, 0.5% CSTY, or 0.5% Cholazol H for 4 weeks. Fasting plasma lipids were measured at weeks 2 and 4, and fecal bile acids were measured at week 4. Both Cholazol H and CSTY were equally effective in significantly lowering plasma TC (-16%, P < .003, and -13%, P < .01, respectively) and nonHDL-C (-22%, P < .004, and -18%, P < .02, respectively), with no significant effect on HDL-C and TG relative to HCD. Cholazol H and CSTY produced a significantly greater concentration of fecal total

  4. Distinguishing Clouds from Ice over the East Siberian Sea, Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    As a consequence of its capability to retrieve cloud-top elevations, stereoscopic observations from the Multi-angle Imaging SpectroRadiometer (MISR) can discriminate clouds from snow and ice. The central portion of Russia's East Siberian Sea, including one of the New Siberian Islands, Novaya Sibir, are portrayed in these views from data acquired on May 28, 2002.

    The left-hand image is a natural color view from MISR's nadir camera. On the right is a height field retrieved using automated computer processing of data from multiple MISR cameras. Although both clouds and ice appear white in the natural color view, the stereoscopic retrievals are able to identify elevated clouds based on the geometric parallax which results when they are observed from different angles. Owing to their elevation above sea level, clouds are mapped as green and yellow areas, whereas land, sea ice, and very low clouds appear blue and purple. Purple, in particular, denotes elevations very close to sea level. The island of Novaya Sibir is located in the lower left of the images. It can be identified in the natural color view as the dark area surrounded by an expanse of fast ice. In the stereo map the island appears as a blue region indicating its elevation of less than 100 meters above sea level. Areas where the automated stereo processing failed due to lack of sufficient spatial contrast are shown in dark gray. The northern edge of the Siberian mainland can be found at the very bottom of the panels, and is located a little over 250 kilometers south of Novaya Sibir. Pack ice containing numerous fragmented ice floes surrounds the fast ice, and narrow areas of open ocean are visible.

    The East Siberian Sea is part of the Arctic Ocean and is ice-covered most of the year. The New Siberian Islands are almost always covered by snow and ice, and tundra vegetation is very scant. Despite continuous sunlight from the end of April until the middle of August, the ice between the island and the

  5. Distinguishing Clouds from Ice over the East Siberian Sea, Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    As a consequence of its capability to retrieve cloud-top elevations, stereoscopic observations from the Multi-angle Imaging SpectroRadiometer (MISR) can discriminate clouds from snow and ice. The central portion of Russia's East Siberian Sea, including one of the New Siberian Islands, Novaya Sibir, are portrayed in these views from data acquired on May 28, 2002.

    The left-hand image is a natural color view from MISR's nadir camera. On the right is a height field retrieved using automated computer processing of data from multiple MISR cameras. Although both clouds and ice appear white in the natural color view, the stereoscopic retrievals are able to identify elevated clouds based on the geometric parallax which results when they are observed from different angles. Owing to their elevation above sea level, clouds are mapped as green and yellow areas, whereas land, sea ice, and very low clouds appear blue and purple. Purple, in particular, denotes elevations very close to sea level. The island of Novaya Sibir is located in the lower left of the images. It can be identified in the natural color view as the dark area surrounded by an expanse of fast ice. In the stereo map the island appears as a blue region indicating its elevation of less than 100 meters above sea level. Areas where the automated stereo processing failed due to lack of sufficient spatial contrast are shown in dark gray. The northern edge of the Siberian mainland can be found at the very bottom of the panels, and is located a little over 250 kilometers south of Novaya Sibir. Pack ice containing numerous fragmented ice floes surrounds the fast ice, and narrow areas of open ocean are visible.

    The East Siberian Sea is part of the Arctic Ocean and is ice-covered most of the year. The New Siberian Islands are almost always covered by snow and ice, and tundra vegetation is very scant. Despite continuous sunlight from the end of April until the middle of August, the ice between the island and the

  6. Chemical characteristics of Siberian boreal forest fire emissions

    NASA Astrophysics Data System (ADS)

    Engling, G.; Popovicheva, O.; Fan, T. S.; Eleftheriadis, K.; Diapouli, E.; Kozlov, V.

    2014-12-01

    Smoke emissions from Siberian boreal forest fires exert critical impacts on the aerosol/climate system of subarctic regions and the Arctic. It is, therefore, crucial to assess the ability of such particles to absorb/scatter incoming solar radiation as well as act as cloud condensation nuclei, which is closely linked to the physical and chemical aerosol properties. However, observations of Siberian wildfire emissions are limited, and no systematic database of smoke particle properties is available for this region to date. As part of this study, ambient aerosol samples were collected during two smoke episodes in Tomsk, Siberia, in the summers of 2012 and 2013. In addition, the chemical composition and optical properties of smoke particles derived from the combustion of typical Siberian fuels, including pine wood and debris, were determined during chamber burn experiments in a large aerosol/combustion chamber under controlled combustion conditions representative of wildfires and prescribed burns. Detailed multi-component characterization of individual particles and bulk properties was accomplished with a suite of techniques, including various types of chromatography, microscopy, spectroscopy, and thermo-optical analysis. Individual particle analysis by SEM-EDX combined with cluster analysis revealed characteristic smoke structural components and major types of particles, which allowed to discriminate between flaming and smoldering regimes, reflected in specific morphological and chemical microstructure. The physicochemical properties representing the combustion phase (smoldering versus flaming) and the degree of processing (fresh versus aged) were assessed in the ambient aerosol based on the chamber burn results. For instance, some chemical transformation (aging of smoke particles) was noticed over a period of two days in the absence of sun light in the combustion chamber for certain chemical species, while the molecular tracer levoglucosan appeared to be rather

  7. 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.

  8. Tumor-related gene changes in immunosuppressive Syrian hamster cholangiocarcinoma.

    PubMed

    Juasook, Amornrat; Aukkanimart, Ratchadawan; Boonmars, Thidarut; Sudsarn, Pakkayanee; Wonkchalee, Nadchanan; Laummaunwai, Porntip; Sriraj, Pranee

    2013-10-01

    The results of a previous study demonstrated that prednisolone enhanced cholangiocarcinogenesis. Therefore, to clarify molecular changes during immunosuppressive cholangiocarcinogenesis, Syrian hamsters were divided into 8 groups: uninfected controls; immunosuppressed Syrian hamsters using prednisolone (P); normal Syrian hamsters administered N-nitrosodimethylamine (ND); immunosuppressed Syrian hamsters administered N-nitrosodimethylamine (NDis); normal Syrian hamsters infected with Opisthorchis viverrini (OV); immunosuppressed Syrian hamsters infected with O. viverrini (OVis); normal Syrian hamsters infected with O. viverrini and administered N-nitrosodimethylamine (CCA); and immunosuppressed Syrian hamsters infected with O. viverrini and administered N-nitrosodimethylamine (CCAis). Syrian hamster livers were used for analysis of tumor-related gene expression and immunohistochemistry through cytokeratin 19 (CK19) and proliferating cell nuclear antigen (PCNA) staining. The tumor-related gene expression results show that CCAis groups at all time points exhibited upregulation of COX-2, IL-6, SOD1, CAT and iNOS and downregulation of p53, which correlated with the predominant expression of CK19 and PCNA in liver tissue. These results suggest that prednisolone enhances cholangiocarcinoma development, which was confirmed by molecular changes.

  9. Comparative study of the toxic effects of gallium arsenide, indium arsenide and arsenic trioxide following intratracheal instillations to the lung of Syrian golden hamsters.

    PubMed

    Tanaka, A; Hirata, M; Omura, M; Zhao, M; Makita, Y; Yamazaki, K; Inoue, N; Gotoh, K

    2000-01-01

    Toxic effects of gallium arsenide (GaAs), indium arsenide (InAs) and arsenic trioxide (As2O3) were studied in male Syrian golden hamsters. GaAs (7.7 mg/kg) and As2O3 (1.3 mg/kg) particles were instilled intratracheally twice a week a total of 16 times, while InAs (7.7 mg/kg) was instilled a total of 14 times. As a control, hamsters were treated with the vehicle, phosphate buffer solution. During the instillation period, the cumulative body weight gain of the InAs-, but not the GaAs- or As2O3-treated hamsters was suppressed significantly, when compared with the control group. Slight to severe inflammatory responses were observed in the lung for all treatment groups. The most severe inflammatory change, characterized by an accumulation of neutrophils and macrophages, exudation, thickness of the pleura and fibrotic proliferation was found in the InAs-treated hamsters. Extensive alveolar or bronchiolar cell hyperplasia with or without keratinizing squamous cell metaplasia was observed in almost all the InAs-treated hamsters. Furthermore, squamous cell metaplasia or squamous cell hyperplasia developed in some of the InAs-treated hamsters, but not in the GaAs- or As2O3-treated hamsters. Slight to mild lesions were found in the convoluted tubules of the kidney in both the GaAs and InAs groups. From the present study, the toxic potency of these particles was provisionally estimated to be in the following order: InAs > GaAs > As2O3, at the dosage level used in this study. Furthermore, there was evidence that InAs particles could induce pulmonary, renal or systemic toxicity, and as such, InAs particles may produce pulmonary precancerous change when instilled intratracheally into hamsters.

  10. 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.

  11. The facial levels of the melting of the Permian - Triassic trap basalts of West Siberian plate and Siberian platform.

    NASA Astrophysics Data System (ADS)

    Sharapov, Victor; Vasiliev, Yury

    2014-05-01

    Statistical processing of numerical information allow to indicate the following regional petro- geochemical characteristics of Permo-Triassic trap magmatism in West Siberian plate WSP: 1) Examined regional petrochemical trend of major element chemistry variation of trap magmatism from north to the south is appeared in increase of the acidity, a decrease of Mg and alumina and potassium of the igneous rocks, for other components existing data do not allow to determine regularities; 2) According to (La/Yb)n, (Gd/Yb)n and(Tb/Yb)n ratios all basic melts belong to the spinel facie. In general the trap basalts of Siberian Platform reveal the following structural facial features are characteristic: 1) From west and east the region of the basalt effusions practically coincides with the area of Devonian sea depressions, 2) from the west to east lava shields are framed by the zones of the variously differentiated intrusive basic bodies grouped within the zones of arched and linear faults; 3) the region of effusive volcanics appearance has the zone - distributed structural - material areas, the tholeitic "super-shield" (plateau Putorana) occupyingthe center part of the Tunguska syneclise), framed from the West, and NW by the local lava shields located in rounded depressions( mulda) in which the lavas are more magnesian, titaniferrous and alkaline. 4) examined overall petrochemical zonation of basic rocks in Siberian platform reveal general decrease from the Norilsk mulda to Angara- Ilim iron-ore deposit region, with the growth of Ti02 and alkalinity of the basic rocks. The statistical wavelet analysis of the cyclic recurrence of the effusive rock sections along the eastern board of Khatanga rift show substantially different characteristics of the spectra of time series, in Norilsk -Kharaelakh depression the low-frequency modules predominate, whereas for The Meimecha-Kotuy effusion section the high frequency values are characteristic. The comparison of the possible facial

  12. A Practical Grammar of the St. Lawrence Island/Siberian Yupik Eskimo Language. Preliminary Edition.

    ERIC Educational Resources Information Center

    Jacobson, Steven A.

    The grammar of the St. Lawrence Island/Siberian Yupik Eskimo language was written for college-level classes containing a mixture of Yupik speakers and non-speakers, and for students learning the language on their own. It uses only the Central Siberian Yupik dialect spoken on St. Lawrence Island (Alaska) and on a small portion of the Asian…

  13. Repeated anabolic-androgenic steroid treatment during adolescence increases vasopressin V(1A) receptor binding in Syrian hamsters: correlation with offensive aggression.

    PubMed

    DeLeon, Katrina R; Grimes, Jill M; Melloni, Richard H

    2002-09-01

    Repeated anabolic-androgenic steroid treatment during adolescence increases hypothalamic vasopressin and facilitates offensive aggression in male Syrian hamsters (Mesocricetus auratus). The current study investigated whether anabolic-androgenic steroid exposure during this developmental period influenced vasopressin V(1A) receptor binding activity in the hypothalamus and several other brain areas implicated in aggressive behavior in hamsters. To test this, adolescent male hamsters were administered anabolic steroids or sesame oil throughout adolescence, tested for offensive aggression, and examined for differences in vasopressin V(1A) receptor binding using in situ autoradiography. When compared with control animals, aggressive, adolescent anabolic steroid-treated hamsters showed significant increases (20-200%) in the intensity of vasopressin V(1A) receptor labeling in several aggression areas, including the ventrolateral hypothalamus, bed nucleus of the stria terminalis, and lateral septum. However, no significant differences in vasopressin V(1A) receptor labeling were found in other brain regions implicated in aggressive responding, most notably the lateral zone from the medial preoptic area to anterior hypothalamus and the corticomedial amygdala. These data suggest that adolescent anabolic steroid exposure may facilitate offensive aggression by increasing vasopressin V(1A) receptor binding in several key areas of the hamster brain.

  14. Human sperm chromosome analysis after subzonal sperm insemination of hamster oocytes

    SciTech Connect

    Cozzi, J.

    1994-09-01

    Sperm microinjection techniques, subzonal sperm insemination (SUZI) and intracytoplasmic sperm injection (ICSI), have achieved a wide spread clinical application for the treatment of male infertility. To date, only one study has focused on sperm karyotypes after microinjection. Martin et al. reported a very high incidence of abnormal human sperm complements after ICSI into hamster oocytes. In the present study, are reported the first human sperm karyotypes after SUZI of hamster oocytes. Spermatozoa from two control donors were treated by calcium ionophore A23187 and injected under the zona of hamster eggs. The microinjected eggs were then cultured for cytogenetic analysis of the pronuclei. Out of 47 analyzed sperm chromosome metaphases, 5 (10.6%) were abnormal, 4 (8.5%) were hypohaploid and 1 (2.1%) had a structural abnormality. The sex ratio was not significantly different from the expected 1:1 ratio. Rates of chromosomal abnormalities in microinjected spermatozoa were similar to those observed in spermatozoa inseminated with zona free eggs, suggesting that SUZI procedure per se does not increase sperm chromosomal abnormalities.

  15. 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

  16. PARENT-OF-ORIGIN GROWTH EFFECTS AND THE EVOLUTION OF HYBRID INVIABILITY IN DWARF HAMSTERS

    PubMed Central

    Brekke, Thomas D.; Good, Jeffrey M.

    2015-01-01

    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 P. 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. PMID:25130206

  17. 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.

  18. Hypolipidemic and Antioxidative Effects of Glossogyne tenuifolia in Hamsters Fed an Atherogenic Diet.

    PubMed

    Lee, Yi-Ning; Hsu, Guoo-Shyng Wang; Lin, Wan-Teng; Lu, Yi-Fa

    2016-05-01

    Glossogyne tenuifolia (GT) Cassini is a special herbal tea in the Penghu Islands, Taiwan, and has a long history of being used as an antipyretic, detoxifying, and anti-inflammatory remedy in folk medicine among local residents. The aim of this study was to investigate the effect of hot water extracts from GT on oxidative stress and lipid metabolism in animals. Five- to 6-week-old male Syrian hamsters were divided into four groups (n = 14) for different treatments, that is: control group (C), high-fat/cholesterol (HF) group, HF diet containing 0.5% (GT0.5) and 1.5% (GT1.5) GT extracts for 4 weeks. Hamsters fed with 0.5% GT powder as well as 1.5% GT powder exhibited reduced serum total cholesterol (TC), conjugated diene of low-density lipoprotein (LDL), and increased serum antioxidant capacity, but 1.5% GT powder was more potent at lowering serum LDL cholesterol and thiobarbituric acid reactive substance concentrations than 0.5% GT. GT extracts significantly lowered liver triacylglycerol (TG) concentration by diminishing activities of fatty acid synthase (FAS) and glucose-6-phosphate dehydrogenase (G-6-PDH). In addition, fecal excretion of cholesterol and bile acids were increased in GT extract groups. In conclusion, GT extracts increase the antioxidative capacity, decrease serum TC, inhibit the activities of FAS and G-6-PDH, and further reduce liver TG accumulation in hamster fed on atherogenic diets.

  19. Photoperiodic changes in opiate binding and their functional implications in golden hamsters.

    PubMed

    Tubbiola, M L; Nock, B; Bittman, E L

    1989-11-27

    Daylength modulates gonadotropin secretion, gonadal steroid hormone feedback, sexual behavior and body weight in male golden hamsters. Endogenous opiates regulate each of these phenomena, and the ability of opiate receptor blockade to elevate serum LH secretion is photoperiod-dependent. We used in vitro autoradiography to localize and quantify effects of daylength in golden hamsters. Hamsters were exposed to stimulatory (14 h light: 10 h dark) or inhibitory (10 h light: 14 h dark) photoperiods for 10 weeks before specific [3H]naloxone binding was assessed. Short days significantly decreased binding in medial amygdala and the intercalated amygdaloid nucleus. This effect was reversed by superior cervical ganglionectomy. No significant effects of daylength were observed in other amygdaloid, hypothalamic or preoptic areas. Lesions of the medial amygdala decreased copulatory behavior, short day-induced weight loss, and anogenital chemoinvestigation but did not affect gonadal regression or other forms of chemoinvestigation. These lesions facilitated testosterone's negative feedback on luteinizing hormone in long days but did not interfere with the potentiation of negative feedback by short days.

  20. Volatile compounds in anal gland of Siberian weasels (Mustela sibirica) and steppe polecats (M. eversmanni).

    PubMed

    Zhang, Jian-Xu; Sun, Lixing; Zhang, Zhi-Bin; Wang, Zu-Wang; Chen, Yi; Wang, Rui

    2002-06-01

    The volatile constituents in anal gland secretions of two sympatric Mustela species, the Siberian weasel (M. sibirica) and steppe polecat (M. eversmanni), were studied by the headspace technique, followed by gas chromatography-mass spectrometry (GC-MS) analysis. Nine sulfur-containing compounds were identified. They were 2,2-dimethylthietane, (Z)- or (E)-2,4-dimethylthietane, (E)-2,3-dimethylthietane, 2-ethylthietane, (E)-2-ethyl-3-methylthietane, (Z)-2-ethyl-3-methylthietane, 2-propylthietane, 3,3-dimethyl-1,2-dithiacyclopentane, and (Z)-3,4-dimethyl-2,2-dithiacyclopentane. Among them, (E)-2-ethyl-3- methylthietanes, (Z)-2-ethyl-3-methylthietanes, and (Z)-3,4-dimethyl-1,2-dithiacyclopentane were present in the polecat but not in the weasel. The predominant compound was 2,2-dimethylthietane in the weasel and (E)- or (Z)-2,4-dimethylthietane in the polecat. These differences were consistent between the two species, regardless of sex and age and, therefore, could possibly be used for species recognition. In the weasel, 2-ethylthietane was found only in the female, and the relative abundance of several compounds was significantly different between males and females. In the polecat, although no sex-specific volatile compounds were found, males and females differed in the relative abundance of several of the compounds. In both species, the relative abundance of some compounds varied with age. We conclude that these volatile compounds can be used to communicate information about species, sex, and age.

  1. Local Mesozoic remagnitization of New Siberian Islands sediments

    NASA Astrophysics Data System (ADS)

    Chernova, Anna; Metelkin, Dmitry; Vernikovsky, Valery; Matushkin, Nikolay

    2017-04-01

    New Siberian Islands (NSI) terrane is one of the key structures of the East Arctic but its tectonic history is still debated. Mesozoic stage in the East Arctic is characterized by active geodynamic events such as closing of the South Anyui Ocean, South Anyui suture forming and Verkhoyansk-Chukotka folding in which NSI terrane has been involved during collision with Siberia. On Lyakhov islands there are discovered thick clastic strata and it is expected that its accumulation occurred in the foretrough during Anyui orogeny in the Late Jurassic - Early Cretaceous [Danukalova, 2009]. During international expeditions to the New Siberian Islands in 2011 and 2013 for paleomagnetic studies Triassic and Devonian deposits on the Kotelny Is. and Late Jurassic-Early Cretaceous sediments of Stolbovoi Is. and Great Lyakhov Is. were tested. The collection was studied by standard paleomagnetic methods and the paleomagnetic directions for these objects were obtained as a result of stepwise demagnetization. The synchronicity of determined magnetization and rock formation was verified by fold test. For all of them it was negative that means the magnetization is post-folding. To estimate the age of expected remagnetization we compared the poles calculated on directions in geographic coordinates with Mesozoic interval of Siberian APWP [Metelkin et al., 2010]. It revealed that obtained NST poles match with its 140-80 Ma interval within the error limits. So we can assume that remagnetization of sediments located along the southern and western boundary of the NSI archipelago coincides with the closure of an oceanic basin and end of accretion-collisional processes associated with the attaching the NSI terrane to Siberia.

  2. Shelf -Basin exchange along the Laptev - East Siberian Seas

    NASA Astrophysics Data System (ADS)

    Anderson, L. G.; Jutterstrom, S.; Stoven, T.; Björk, G. M.; Holby, O.; Jakobsson, M.; Semiletov, I. P.; Tanhua, T. S.; Ulfsbo, A.

    2016-02-01

    The Siberian Shelf Seas are areas of extensive biogeochemical transformation of organic matter, which in combination with brine production from sea ice formation results in cold bottom water of relatively high salinity and nutrient concentrations, as well as low oxygen and pH levels. Data from the SWERUS-C3 expedition on the icebreaker Oden in July to September 2014 show the distribution of these bottom waters along the Siberian continental margin from about 140 to 180 oE. The nutrient maximum water, classically named the Upper Halocline, is absent in the west, over the Lomonosov Ridge. It is clearly seen in the Makarov Basin from about 150 oE and becomes more intense further to the east. At the intercept of the Mendeleev Rise and the continental slope the nutrient maximum is still intense, but more vertically distributed. Hence it is also found at higher salinities, up to 34.5. There are strong indications that this high salinity, high nutrient water is produced on the shelf west of 160 oE, and that formation of such water is coupled with substantial sea ice production at the outer continental shelf. Remote sensing data show much more open water than previously during the summer months during the last 10 years in the area north of the New Siberian Islands. East of 170 oE the transient tracers show significant less ventilated waters below about 100 m depth, likely an indication of a boundary current steered away from the shelf slope by the Mendeleev Rise.

  3. Fir Decline and Mortality in the Southern Siberian Mountains

    NASA Technical Reports Server (NTRS)

    Kharuk, Viacheslav I.; Im, Sergei T.; Petrov, Ilya A.; Dvinskaya, Mariya, L.; Fedotova, Elena V.; Ranson, Kenneth J.

    2016-01-01

    Increased dieback and mortality of dark needle conifer (DNC) stands (composed of fir (Abies sibirica),Siberian pine (Pinus sibirica) and spruce (Picea obovata))were documented in Russia during recent decades. Here we analyzed spatial and temporal patterns of fir decline and mortality in the southern Siberian Mountains based on satellite, in situ and dendrochronological data. The studied stands are located within the boundary between DNC taiga to the north and forest-steppe to the south. Fir decline and mortality were observed to originate where topographic features contributed to maximal water-stress risk, i.e., steep (1825),convex, south-facing slopes with a shallow well-drained root zone. Fir regeneration survived droughts and increased stem radial growth, while upper canopy trees died. Tree ring width(TRW) growth negatively correlated with vapor pressure deficit (VPD), drought index and occurrence of late frosts, and positively with soil water content. Previous year growth conditions (i.e., drought index, VPD, soil water anomalies)have a high impact on current TRW (r 0.600.74). Fir mortality was induced by increased water stress and severe droughts (as a primary factor) in synergy with bark-beetles and fungi attacks (as secondary factors). Dendrochronology data indicated that fir mortality is a periodic process. In a future climate with increased aridity and drought frequency, fir (and Siberian pine) may disappear from portions of its current range (primarily within the boundary with the forest steppe)and is likely to be replaced by drought-tolerant species such as Pinus sylvestris and Larix sibirica.

  4. Fir Decline and Mortality in the Southern Siberian Mountains

    NASA Technical Reports Server (NTRS)

    Kharuk, Viacheslav I.; Im, Sergei T.; Petrov, Ilya A.; Dvinskaya, Mariya, L.; Fedotova, Elena V.; Ranson, Kenneth J.

    2016-01-01

    Increased dieback and mortality of dark needle conifer (DNC) stands (composed of fir (Abies sibirica),Siberian pine (Pinus sibirica) and spruce (Picea obovata)) were documented in Russia during recent decades. Here we analyzed spatial and temporal patterns of fir decline and mortality in the southern Siberian Mountains based on satellite, in situ and dendrochronological data. The studied stands are located within the boundary between DNC taiga to the north and forest-steppe to the south. Fir decline and mortality were observed to originate where topographic features contributed to maximal water-stress risk, i.e., steep (18 deg to 25 deg), convex, south-facing slopes with a shallow well-drained root zone. Fir regeneration survived droughts and increased stem radial growth, while upper canopy trees died. Tree ring width (TRW) growth negatively correlated with vapor pressure deficit (VPD), drought index and occurrence of late frosts, and positively with soil water content. Previous year growth conditions (i.e., drought index, VPD, soil water anomalies) have a high impact on current TRW (r = 0.60 to 0.74). Fir mortality was induced by increased water stress and severe droughts (as a primary factor) in synergy with bark-beetles and fungi attacks (as secondary factors). Dendrochronology data indicated that fir mortality is a periodic process. In a future climate with increased aridity and drought frequency, fir (and Siberian pine) may disappear from portions of its current range (primarily within the boundary with the forest- steppe) and is likely to be replaced by drought-tolerant species such as Pinus sylvestris and Larix sibirica.

  5. Northern and eastern margins of the Siberian continent in Triassic

    SciTech Connect

    Egorov, A.Yu. )

    1993-09-01

    Siliciclastic sedimentation has been predominant on the northern and eastern margins of the Siberian continent since the Triassic period. Seven transgression-regression cycles can be recognized in the Triassic succession: Griesbachien-Dienerian, Smithian-Low Spathian, Upper Spathian, Anissian (with subcycles), Ladian, Carnian, and Norlan (with subcycles). All zonal units were distinguished within transgressive portions of the cycles. Regressive portions of the cycles formed practically instantaneously. Very high sedimentation rate (300-3000 mm/1000 yr), specific structures of sedimentary rocks, and distribution of unconformities led to the conclusion that active avalanche sedimentation at the basin margins was of major significance. six facies regions are recognized in the sedimentation area: Taimyr, Kotuy-Anabar, Leno-Anabar, Bur-Olenek, Verkhoyansk, and Novosibirsk (New Siberian Islands). The main source areas were located at the Patoma Mountains for the eastern margin and at the Anabar anticline and Olenek uplift for the northern margin. Most sediments were transported to the eastern margin by a large river with a huge delta which was similar in size to the modern Lena's delta. Sediments were further distributed by contour streams. Local synsedimentary structures controlled the paleogeography of the entire area. The paleogeographical evolution of the eastern margin is the history of this delta development. The rifting activities with the trappean magmatism were the main events at the northern margin, especially in the Talmyr area. The pelagic sedimentation has been predominant in the New Siberian Islands area and most of the Laptev Sea aquatoria. The organic-rich sediments have been distinguished in Low Olenekian (Smithian), Low Anissian, Low Ladinian, and Low Carnian substages. Most of them could be hydrocarbon source rocks. Triassic oil and gas seeps have been discovered at the northern portion of the Vilyui syncline, near the Lena's delta and the Nordvic Bay.

  6. Fir Decline and Mortality in the Southern Siberian Mountains

    NASA Technical Reports Server (NTRS)

    Kharuk, Viacheslav I.; Im, Sergei T.; Petrov, Ilya A.; Dvinskaya, Mariya, L.; Fedotova, Elena V.; Ranson, Kenneth J.

    2016-01-01

    Increased dieback and mortality of dark needle conifer (DNC) stands (composed of fir (Abies sibirica),Siberian pine (Pinus sibirica) and spruce (Picea obovata))were documented in Russia during recent decades. Here we analyzed spatial and temporal patterns of fir decline and mortality in the southern Siberian Mountains based on satellite, in situ and dendrochronological data. The studied stands are located within the boundary between DNC taiga to the north and forest-steppe to the south. Fir decline and mortality were observed to originate where topographic features contributed to maximal water-stress risk, i.e., steep (1825),convex, south-facing slopes with a shallow well-drained root zone. Fir regeneration survived droughts and increased stem radial growth, while upper canopy trees died. Tree ring width(TRW) growth negatively correlated with vapor pressure deficit (VPD), drought index and occurrence of late frosts, and positively with soil water content. Previous year growth conditions (i.e., drought index, VPD, soil water anomalies)have a high impact on current TRW (r 0.600.74). Fir mortality was induced by increased water stress and severe droughts (as a primary factor) in synergy with bark-beetles and fungi attacks (as secondary factors). Dendrochronology data indicated that fir mortality is a periodic process. In a future climate with increased aridity and drought frequency, fir (and Siberian pine) may disappear from portions of its current range (primarily within the boundary with the forest steppe)and is likely to be replaced by drought-tolerant species such as Pinus sylvestris and Larix sibirica.

  7. Fir Decline and Mortality in the Southern Siberian Mountains

    NASA Technical Reports Server (NTRS)

    Kharuk, Viacheslav I.; Im, Sergei T.; Petrov, Ilya A.; Dvinskaya, Mariya, L.; Fedotova, Elena V.; Ranson, Kenneth J.

    2016-01-01

    Increased dieback and mortality of dark needle conifer (DNC) stands (composed of fir (Abies sibirica),Siberian pine (Pinus sibirica) and spruce (Picea obovata)) were documented in Russia during recent decades. Here we analyzed spatial and temporal patterns of fir decline and mortality in the southern Siberian Mountains based on satellite, in situ and dendrochronological data. The studied stands are located within the boundary between DNC taiga to the north and forest-steppe to the south. Fir decline and mortality were observed to originate where topographic features contributed to maximal water-stress risk, i.e., steep (18 deg to 25 deg), convex, south-facing slopes with a shallow well-drained root zone. Fir regeneration survived droughts and increased stem radial growth, while upper canopy trees died. Tree ring width (TRW) growth negatively correlated with vapor pressure deficit (VPD), drought index and occurrence of late frosts, and positively with soil water content. Previous year growth conditions (i.e., drought index, VPD, soil water anomalies) have a high impact on current TRW (r = 0.60 to 0.74). Fir mortality was induced by increased water stress and severe droughts (as a primary factor) in synergy with bark-beetles and fungi attacks (as secondary factors). Dendrochronology data indicated that fir mortality is a periodic process. In a future climate with increased aridity and drought frequency, fir (and Siberian pine) may disappear from portions of its current range (primarily within the boundary with the forest- steppe) and is likely to be replaced by drought-tolerant species such as Pinus sylvestris and Larix sibirica.

  8. Transformation of Hamster Embryo Cells and Tumor Induction in Newborn Hamsters by Simian Adenovirus SV11

    PubMed Central

    Casto, Bruce C.

    1969-01-01

    Simian adenovirus, SV11, readily transformed hamster embryo cell cultures in vitro and produced tumors in vivo when inoculated into newborn hamsters. Foci consisting of small, loosely attached, rounded cells could be seen as early as 7 days postinoculation. Many of these cells contained several nuclei or the nucleus was multilobed. The cells grew without extensive cell to cell contact or formed small chains or clusters when passaged in vitro. This pattern of cell morphology and growth has not been reported with other simian or human adenovirus-transformed cells. Linearity of foci formation with virus dilution was observed when the virus multiplicity was less than 3 plaque-forming units (PFU)/cell. The PFU to focus-forming units ratio for SV11 was found to be 2 × 104 to 4 × 104, which is approximately 5- to 10-fold and 50- to 100-fold lower than those reported for simian adenovirus, SA7, and human adenovirus type 12, respectively. Cells transformed by SV11: (i) produced tumors when inoculated into young hamsters, (ii) contained tumor antigen which reacts with serum obtained from hamsters bearing SV11 passaged tumors, and (iii) could be propagated in vitro through an indefinite number of generations. Images PMID:5786181

  9. 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...

  10. 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...

  11. North Siberian lakes: A methane source fueled by Pleistocene carbon

    SciTech Connect

    Zimov, S.A.; Davidov, S.P.; Prosiannikov, S.F.; Trumbore, S.

    1997-08-08

    The sizes of major sources and sinks of atmospheric methane (CH{sub 4}), an important greenhouse gas, are poorly known. CH{sub 4} from north Siberian lakes contributes {approximately}1.5 teragrams CH{sub 4} year{sup -1} to observed winter increases in atmospheric CH{sub 4} concentration at high northern latitudes. CH{sub 4} emitted from these lakes in winter had a radiocarbon age of 27,200 years and was derived largely from Pleistocene-aged carbon.

  12. Triumph of Technology Over Geography - Unlocking the Siberian Maritime Icebox,

    DTIC Science & Technology

    1987-05-22

    with global political consequences. Such may be the case with the recently completed Siberian gas pipeline to Western. Ejr.p& (5) le e.Ce.,M dZ.’𔃾...increasingly important to the economic development of the Soviet 4* A. in ev riple, the Canadiir Mackenzie River Villey gal- pipeline pro ieO was blocked... pressurized with diesel powered fanS to achieve the capability of lifting and moving large loads. This technique uses only a relatively low footprint

  13. 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

  14. The Nature of Mantle Sources for Perm-Triassic Traps of Western Siberian Plate and Siberian Platform

    NASA Astrophysics Data System (ADS)

    Sharapov, V.; Perepechko, Y.; Rakhmenkulova, I.

    2007-12-01

    This work deals with the consistent dynamics for the development of melting zones due to convection in the upper mantle and the adjacent melting zones in inhomogeneous lithosphere. This model is studied for magma systems of Western Siberian Plate and Siberian Platform (SP). The results of numerical modeling allow us to conclude the following: 1. Structural and petrochemical zoning for Perm-Triassic trap magmatism of the Siberian Platform can be explained due to two-level melting of mantle rocks over hotspots (McKenzie, 1984). An alternative approach to explain mechanism of trap magmatism because of hydrodynamic evolution of magma under inhomogeneous lithosphere (King, Anderson, 1995) does not allow us to obtain voluminous melting of the mantle rocks for the lithosphere. 2. Main volumes of tholeiitic magmas (which compose both the intrusives in the SP platform cover and SP profiles of lava shield) are due to melting of mantle rocks in the thinned parts of the lithosphere over a number of spread hotspots. 3. The area of partial melting in the lithosphere is appearing after the zone of decompressing melting developed to its maximum extent, under the conditions of convection in the upper mantle. The melting zone appearing at the depth about 70-100 km has a plate-like shape, thickness up to ~20-30 km and horizontal extent coexistent with the sizes of the lava shield. This research was supported by the President's grants NSh-1573.2003.5, and by the Russian Ministry Science and Education grant RNP.2.1.1.702.

  15. Lower weight gain and hepatic lipid content in hamsters fed high fat diets supplemented with white rice protein, brown rice protein, and soy protein and their hydrolysates

    USDA-ARS?s Scientific Manuscript database

    The physiological effects of the hydrolysates from white rice, brown rice, and soy isolate were compared to the original protein source. White rice, brown rice, and soy protein were hydrolyzed with the food grade enzyme, alcalase2.4 L®. Male Syrian hamsters were fed high-fat diets containing eithe...

  16. Dietary supplementation of Chardonnay grape seed flour reduces plasma cholesterol concentration, hepatic steatosis, and abdominal fat content in high-fat diet-induced obese hamsters

    USDA-ARS?s Scientific Manuscript database

    The mechanisms for the hypocholesterolemic and anti-obesity effects of grape seed flours derived from white and red winemaking processing were investigated. Male Golden Syrian hamsters were fed high-fat (HF) diets supplemented with 10% partially defatted grape seed flours from Chardonnay (ChrSd), Ca...

  17. 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.

  18. Effect of geraniol, a plant derived monoterpene on lipids and lipid metabolizing enzymes in experimental hyperlipidemic hamsters.

    PubMed

    Jayachandran, Muthukumaran; Chandrasekaran, Balaji; Namasivayam, Nalini

    2015-01-01

    Hyperlipidemia is a major, modifiable risk factor for atherosclerosis and cardiovascular disease. In the present study, we have focused on the effect of different doses of geraniol (GOH) on the lipid profile and lipid metabolizing enzymes in atherogenic diet (AD) fed hamsters. Male Syrian hamsters were grouped into seven: group 1 were control animals; group 2 were animals fed GOH alone (200 mg/kg b.w); group 3 were animals fed AD (10 % coconut oil, 0.25 % cholesterol, and 0.25 % cholic acid); group 4 were animals fed AD + corn oil (2.5 ml/kg b.w); and groups 5, 6, and 7 were fed AD as in group 3 + different doses of GOH (50, 100, and 200 mg/kg b.w), respectively, for 12 weeks. At the end of the experimental period, animals were sacrificed by cervical dislocation and various assays were performed in the plasma and tissues. The AD hamsters showed marked changes in lipid profile and lipid metabolizing enzymes. However, supplementation with GOH counteracted the hyperlipidemia by inhibiting HMG CoA reductase and suppressing lipogenesis. The antihyperlipidemic efficacy of GOH was found to be effective at the dose of 100 mg/kg b.w. This study illustrates that GOH is effective in lowering the risk of hyperlipidemia in AD fed hamsters.

  19. Effects of induced wheel running on the circadian activity rhythms of Syrian hamsters: entrainment and phase response curve.

    PubMed

    Reebs, S G; Mrosovsky, N

    1989-01-01

    The goal of this study was to provide an example of nonsocial and nonphotic entrainment in Syrian hamsters, together with a corresponding phase response curve (PRC). Fourteen male hamsters were given 2-hr bouts of induced activity (mostly wheel running) at 23.83-hr intervals in constant darkness (DD). The activity onsets of 10 hamsters entrained to this manipulation, with no anticipatory activity present. After entrainment, the rhythms resumed free-running from a time 0.66-3.91 hr after the onset of the last bout of induced activity. Postentrainment free-running periods were shorter than pre-entrainment values. The PRC for 2-hr pulses of induced activity in DD revealed phase advances induced in some animals between circadian time (CT) 4 and CT 11 (approximately the last half of the hamsters' rest period), and delays between CT 23 and CT 3 and between CT 17 and CT 20. The CTs for phase advances are compatible with the phase angle differences observed between rhythm and zeitgeber at the end of entrainment. Many features of the results (not all animals entraining, PRC characteristics, lack of observable anticipation to the daily stimuli, phase relationship between zeitgeber and activity rhythms) are similar to those from a previous study on social entrainment in this species (Mrosovsky, 1988). These similarities reinforce the idea that induced activity and social zeitgebers act on activity rhythms via a common mechanism.

  20. Responses of Siberian ferrets to secondary zinc phosphide poisoning

    USGS Publications Warehouse

    Hill, E.F.; Carpenter, J.W.

    1982-01-01

    The hazard of operational-type applications of zinc phosphide (Zn3P2) on a species closely related to the black-footed ferret (Mustela nigripes), was evaluated by feeding 16 Siberian ferrets (M. eversmanni) rats that had been killed by consumption of 2% zinc phosphide treated bait or by an oral dose of 40, 80, or 160 mg of Zn3P2. All ferrets accepted rats and a single emesis by each of 3 ferrets was the only evidence of acute intoxication. All ferrets learned to avoid eating gastrointestinal tracts of the rats. Subacute zinc phosphide toxicity in the ferrets was indicated by significant decreases (18-48%) in hemoglobin, increases of 35-91 % in serum iron, and elevated levels of serum globulin, cholesterol, and triglycerides. Hemoglobin/iron, urea nitrogen/creatinine, and albumin/globulin ratios also were altered by the treatments. This study demonstrated that Siberian ferrets, or other species with a sensitive emetic reflex, are afforded a degree of protection from acute zinc phosphide poisoning due to its emetic action. The importance of toxicity associated with possible respiratory, liver, and kidney damage indicated by altered blood chemistries is not known.

  1. Siberian Arctic black carbon sources constrained by model and observation.

    PubMed

    Winiger, Patrik; Andersson, August; Eckhardt, Sabine; Stohl, Andreas; Semiletov, Igor P; Dudarev, Oleg V; Charkin, Alexander; Shakhova, Natalia; Klimont, Zbigniew; Heyes, Chris; Gustafsson, Örjan

    2017-02-14

    Black carbon (BC) in haze and deposited on snow and ice can have strong effects on the radiative balance of the Arctic. There is a geographic bias in Arctic BC studies toward the Atlantic sector, with lack of observational constraints for the extensive Russian Siberian Arctic, spanning nearly half of the circum-Arctic. Here, 2 y of observations at Tiksi (East Siberian Arctic) establish a strong seasonality in both BC concentrations (8 ng⋅m(-3) to 302 ng⋅m(-3)) and dual-isotope-constrained sources (19 to 73% contribution from biomass burning). Comparisons between observations and a dispersion model, coupled to an anthropogenic emissions inventory and a fire emissions inventory, give mixed results. In the European Arctic, this model has proven to simulate BC concentrations and source contributions well. However, the model is less successful in reproducing BC concentrations and sources for the Russian Arctic. Using a Bayesian approach, we show that, in contrast to earlier studies, contributions from gas flaring (6%), power plants (9%), and open fires (12%) are relatively small, with the major sources instead being domestic (35%) and transport (38%). The observation-based evaluation of reported emissions identifies errors in spatial allocation of BC sources in the inventory and highlights the importance of improving emission distribution and source attribution, to develop reliable mitigation strategies for efficient reduction of BC impact on the Russian Arctic, one of the fastest-warming regions on Earth.

  2. Adaptive dimensions of health research among indigenous Siberians.

    PubMed

    Snodgrass, J Josh; Sorensen, Mark V; Tarskaia, Larissa A; Leonard, William R

    2007-01-01

    Present evidence suggests that modern humans were the first hominid species to successfully colonize high-latitude environments (> or =55 degrees N). Given evidence for a recent (<200,000 years) lower latitude naissance of modern humans, the global dispersal and successful settlement of arctic and subarctic regions represent an unprecedented adaptive shift. This adaptive shift, which included cultural, behavioral, and biological dimensions, allowed human populations to cope with the myriad environmental stressors encountered in circumpolar regions. Although unique morphological and physiological adaptations among contemporary northern residents have been recognized for decades, human biologists are only now beginning to consider whether biological adaptations to regional environmental conditions influence health changes associated with economic modernization and lifestyle change. Recent studies have documented basal metabolic rates (BMRs) among indigenous Siberian populations that are systematically elevated compared to lower latitude groups; this metabolic elevation apparently is a physiological adaptation to cold stress experienced in the circumpolar environment. Important health implications of metabolic adaptation are suggested by research with the Yakut (Sakha), Evenki, and Buriat of Siberia. BMR is significantly positively correlated with blood pressure, independently of body size, body composition, and various potentially confounding variables (e.g., age and smoking). Further, this research has documented a significant negative association between BMR and LDL cholesterol, which remains after controlling for potential confounders; this suggests that high metabolic turnover among indigenous Siberians has a protective effect with regard to plasma lipid levels. These results underscore the importance of incorporating an evolutionary approach into health research among northern populations.

  3. Siberian Chemical Combine laboratory project work plan, fiscal year 1999

    SciTech Connect

    Morgado, R.E.; Acobyan, R.; Shropsire, R.

    1998-12-31

    The Siberian Chemical Combine (SKhK), Laboratory Project Work Plan (Plan) is intended to assist the US Laboratory Project Team, and Department of Energy (DOE) staff with the management of the FY99 joint material protection control and accounting program (MPC and A) for enhancing nuclear material safeguards within the Siberian Chemical Combine. The DOE/Russian/Newly Independent States, Nuclear Material Task Force, uses a project work plan document for higher-level program management. The SKhK Plan is a component of the Russian Defense related Sites` input to that document. In addition, it contains task descriptions and a Gantt Chart covering the FY99 time-period. This FY99 window is part of a comprehensive, Project Status Gantt Chart for tasking and goal setting that extends to the year 2003. Secondary and tertiary levels of detail are incorporated therein and are for the use of laboratory project management. The SKhK Plan is a working document, and additions and modifications will be incorporated as the MPC and A project for SKhK evolves.

  4. Siberian Arctic black carbon sources constrained by model and observation

    PubMed Central

    Andersson, August; Eckhardt, Sabine; Stohl, Andreas; Semiletov, Igor P.; Dudarev, Oleg V.; Charkin, Alexander; Shakhova, Natalia; Klimont, Zbigniew; Heyes, Chris; Gustafsson, Örjan

    2017-01-01

    Black carbon (BC) in haze and deposited on snow and ice can have strong effects on the radiative balance of the Arctic. There is a geographic bias in Arctic BC studies toward the Atlantic sector, with lack of observational constraints for the extensive Russian Siberian Arctic, spanning nearly half of the circum-Arctic. Here, 2 y of observations at Tiksi (East Siberian Arctic) establish a strong seasonality in both BC concentrations (8 ng⋅m−3 to 302 ng⋅m−3) and dual-isotope–constrained sources (19 to 73% contribution from biomass burning). Comparisons between observations and a dispersion model, coupled to an anthropogenic emissions inventory and a fire emissions inventory, give mixed results. In the European Arctic, this model has proven to simulate BC concentrations and source contributions well. However, the model is less successful in reproducing BC concentrations and sources for the Russian Arctic. Using a Bayesian approach, we show that, in contrast to earlier studies, contributions from gas flaring (6%), power plants (9%), and open fires (12%) are relatively small, with the major sources instead being domestic (35%) and transport (38%). The observation-based evaluation of reported emissions identifies errors in spatial allocation of BC sources in the inventory and highlights the importance of improving emission distribution and source attribution, to develop reliable mitigation strategies for efficient reduction of BC impact on the Russian Arctic, one of the fastest-warming regions on Earth. PMID:28137854

  5. Siberian Arctic black carbon sources constrained by model and observation

    NASA Astrophysics Data System (ADS)

    Winiger, Patrik; Andersson, August; Eckhardt, Sabine; Stohl, Andreas; Semiletov, Igor P.; Dudarev, Oleg V.; Charkin, Alexander; Shakhova, Natalia; Klimont, Zbigniew; Heyes, Chris; Gustafsson, Örjan

    2017-02-01

    Black carbon (BC) in haze and deposited on snow and ice can have strong effects on the radiative balance of the Arctic. There is a geographic bias in Arctic BC studies toward the Atlantic sector, with lack of observational constraints for the extensive Russian Siberian Arctic, spanning nearly half of the circum-Arctic. Here, 2 y of observations at Tiksi (East Siberian Arctic) establish a strong seasonality in both BC concentrations (8 ngṡm-3 to 302 ngṡm-3) and dual-isotope-constrained sources (19 to 73% contribution from biomass burning). Comparisons between observations and a dispersion model, coupled to an anthropogenic emissions inventory and a fire emissions inventory, give mixed results. In the European Arctic, this model has proven to simulate BC concentrations and source contributions well. However, the model is less successful in reproducing BC concentrations and sources for the Russian Arctic. Using a Bayesian approach, we show that, in contrast to earlier studies, contributions from gas flaring (6%), power plants (9%), and open fires (12%) are relatively small, with the major sources instead being domestic (35%) and transport (38%). The observation-based evaluation of reported emissions identifies errors in spatial allocation of BC sources in the inventory and highlights the importance of improving emission distribution and source attribution, to develop reliable mitigation strategies for efficient reduction of BC impact on the Russian Arctic, one of the fastest-warming regions on Earth.

  6. A case report of the management of demodicosis in the golden hamster.

    PubMed

    Hasegawa, T

    1995-04-01

    A 1.6 year-old male golden hamster was presented with alopecia on the back. The animal's physical condition was slightly below normal, and moderate pruritus was observed. Examination of skin scraping revealed mites identified as Demodex sp. Initially, combined therapy using 1% of selenium sulfide shampoo and a topical application of 0.013% amitraz was carried out, although this was not completely successful. Repeated use of 0.017% coumaphos was effective in achieving a complete cure of the alopecia associated with demodicosis. No adverse side effects were recognized during the treatment of this case.

  7. Species differences in mutagenicity testing: I. Micronucleus and SCE tests in rats, mice, and Chinese hamsters with aflatoxin B1.

    PubMed

    Madle, E; Korte, A; Beek, B

    1986-01-01

    Three animal species used in in vivo mutagenicity testing--rats, mice and Chinese hamsters--were compared with respect to their mutagenic response to the mycotoxin aflatoxin B1 (AFB1). The micronucleus test and the SCE test with bone marrow cells were chosen as test methods, employing similar protocols for all species. The mutagenic potential of AFB1 was detected with rats and mice but not with Chinese hamsters. Rats were more susceptible to the mutagenic action of AFB1 than mice with regard to the effective dose. A difference in sensitivity between males and females was evident in rats and mice: male animals exhibited higher induced micronucleus frequencies than females, and a clear SCE-inducing effect was only detectable in male animals. These results are in agreement with those of in vitro and carcinogenicity studies. They may be due to metabolic differences between the species and sexes, predominantly differences in glutathione conjugation of the reactive AFB1 epoxide and in the formation of the metabolite aflatoxicol. Furthermore, it could be demonstrated that AFB1 seems to be a more potent inducer of micronuclei than of SCE. Since our results obtained with rats and mice were clearly positive, but with the Chinese hamster the mutagenic potential of AFB1 was not detectable with the test systems used, it can be concluded that the choice of an "inappropriate" test species may lead to a false negative judgment on the genotoxic potential of a test compound.

  8. A 13-week toxicity study of acrylamide administered in drinking water to hamsters.

    PubMed

    Imai, Toshio; Kitahashi, Tsukasa

    2014-01-01

    Acrylamide (AA) is known to induce tumors in various organs/tissues in rats and mice. Epidemiological studies of oral exposure have generated controversial results but mortality studies of people who work with AA have indicated increased rates of pancreatic cancer. In the present study, for dose selection for chronic toxicity/carcinogenicity studies, 13-week toxicity of AA was evaluated in Syrian hamsters, which are sensitive to induction of pancreatic ductal carcinogenesis, at concentrations required to provide doses of 0 (control), 20, 30 and 50 mg kg(-1) body weight in drinking water. Treatment with AA caused abnormal gait advancing to hind limb paralysis in all males and females at 50 mg kg(-1). Body weights in 30 and 50 mg kg(-1) males and 50 mg kg(-1) females were lower than in the controls. At termination of the study, red blood cells (RBC) and hemoglobin (Hb) were decreased or showed a tendency for a decrease at 20 and 30 mg kg(-1) in females. Microscopically, axonal/myelin degeneration of sciatic nerves was observed in all AA-treated groups with dose dependence. No obvious changes were found in pancreatic ducts/ductules in any groups of animal. These results indicated the maximum tolerated dose for long-term studies of AA to be 20 mg kg(-1) or less in both male and female Syrian hamsters.

  9. Influence of Siberian High on temperature variability over northern areas of South Asia

    NASA Astrophysics Data System (ADS)

    Riaz, Syed Muhammad Fahad; Iqbal, Muhammad Jawed; Baig, Mirza Jawwad

    2017-05-01

    Siberian High pressure plays a significant role in wintertime climate variability over South Asia. It brings coldest air masses in the region. The available literature has linked Siberian High with climate of East Asia, central Asia, and Eurasia. This paper examines the linkage between Siberian High pressure and inter-annual variations in temperature over the region of South Asia during winters. The methods employed in this study are that of centers of action approach, maximum covariance, and canonical correlation analyses. The wintertime temperature is not only significantly influenced by the intensity of Siberian High pressure, but it is also significantly correlated with zonal movement of Indian Ocean High. The intensity of Siberian High pressure explains more variance of the temperature during winters over the South Asian region than that of large-scale circulation phenomena, namely, Arctic Oscillation, North Atlantic Oscillation, and El-Nino-Southern Oscillation. A linear model of wintertime temperature has also been constructed using the Siberian High pressure index and the Indian Ocean High longitudinal index, which explains 28% variability of wintertime temperature for the Northern part of South Asia. We have also presented the justification that this statistical evidence is supported by the circulations and changes in the atmosphere. The modes having maximum possible covariance between the regional wintertime temperature and sea-level pressure of Siberian High have been isolated using the method of maximum covariance analysis and the modes having maximum possible correlations between the two fields have been isolated using canonical correlation analysis.

  10. Plume or no Plume, the Case of the Siberian Trap Formation

    NASA Astrophysics Data System (ADS)

    Reichow, M. K.; Saunders, A. D.; White, R. V.; Al'Mukhamedov, A. I.; Medvedev, A. I.; Inger, S.

    2003-12-01

    The generation mechanism of continental large igneous provinces, such as the Siberian Traps, are matters of recent debate, particularly their relation to mantle plumes derived from the Earth's interior. Alternative models relate the formation of large igneous provinces to bolide impacts or small-scale convection at the boundary of asymmetric lithospheres. Neither of these models is without criticism and each model cannot explain all characteristics of continental flood basalt formation alone. However, strong support for the involvement of a mantle plume comes from the observation that large volumes of basaltic melts ( ˜3 x 106 km3) erupted within a short period of time (< 1 My). Such high magma flux rates can only realistically be produced by decompression melting in the head of an uprising mantle plume. Although several areas surrounding the Siberian craton have been attributed to the Siberian Traps volcanic activity, the entire extent remains conjectural. Basaltic and gabbroic rocks occur throughout the West Siberian Basin (WSB) beneath a thick succession of Mesozoic and Cenozoic sediments. Further to the north of the Siberian craton, on the Taimyr Peninsula, are also basalt and dolerite rocks. We have obtained more than 100 samples from both areas and compared chemical data with data from the Siberian Traps. The basalts have chemical characteristics typical of fractionated, contaminated continental flood basalts (e.g. low Mg#, negative Nb anomaly). Trace element modelling suggests that the basalts represent different degrees of partial melting and crustal contamination. The major and trace element data from the WSB and Taimyr basalts show strong affinities with Siberian Trap basalts that precede the main pulse of volcanism extruded over large areas of the Siberian craton. Although the major and trace element data are consistent with a plume origin for the Siberian Traps, they cannot prove it; however, magma volume and timing constraints do strongly suggest that

  11. Schistosoma japonicum-infected hamsters (Mesocricetus auratus) used as a model in experimental chemotherapy with praziquantel, artemether, and OZ compounds.

    PubMed

    Xiao, Shu-hua; Mei, Jing-yan; Jiao, Pei-ying

    2011-02-01

    The purpose of the study is to better understand the antischistosomal properties of artemether, praziquantel, and ozonide (OZ) compounds (synthetic trioxolanes, secondary ozonides) in hamster (Mesocricetus auratus) model. A total of 230 male hamsters infected each with 100 Schistosoma japonicum cercariae were used in the study. Groups of five to ten hamsters were treated orally with artemether, praziquantel, and OZ78 or OZ277 7-35 days post-infection at single doses of 50, 100, 150, or 200 mg/kg. Untreated but infected hamsters in each batch of test served as the control. All treated hamsters were sacrificed 4 weeks post-treatment for collection of residual worms using perfusion technique. Nonparametric method (Mann-Whitney test) was used to analyze the data. In groups of five hamsters treated with artemether 7, 14, 21, 28, and 35 days post-infection at single doses of 150 and 200 mg/kg, the difference of mean worm burden between each treated group and control group was statistically significant (P<0.01). Apart from individual group, no difference in mean worm burden between each two groups of them was seen (P>0.05). Further test with various single doses of 50-200 mg/kg confirmed the similar susceptibility of 7-day-old juvenile and 35-day-old adult schistosomes to artemether. After administration of praziquantel 100 mg/kg to groups of five hamsters 7, 21, and 35 days post-infection, higher worm burden reduction of 95.5% was seen in the group with 35-day-old adult schistosomes while in the groups with 7- and 21-day-old juvenile schistosomes, poor efficacy was seen with mean worm burden reductions of 36.6% and 35.6%. In the same batch of hamster treated with praziquantel 200 mg/kg, the moderate effect of the drug against 7- and 21-day-old worms was seen, but their mean worm burden was significantly higher than that of the group with adult schistosomes. In comparison of artemether and praziquantel against various stages of schistosomes, the results further

  12. Optimization Of Coherence Estimation Window Size Aiming At Growing Stock Volume Retrieval In Siberian Forest

    NASA Astrophysics Data System (ADS)

    Stelmaszczuk-Gorska, Martyna; Thiel, Christian; Schmullius, Christiane

    2013-12-01

    This research was conducted to find the optimal coherence estimation window size aiming at growing stock volume (GSV) retrieval in Siberian Forest. Additionally, the properties of ALOS PALSAR L-band interferometric coherence of Siberian boreal forest have been presented. It was confirmed that the data acquired during frozen conditions are better suited for the growing stock volume retrieval, showing high coherence for sparse forest and low coherence for dense forest. It was concluded that at least ~ 60 equivalent number of looks (ENL) are necessary to achieve a compromise between a good spatial resolution and reliable estimation of coherence using ALOS PALSAR FBS images for Siberian forest.

  13. First test of a partial Siberian snake for acceleration of polarized protons

    NASA Astrophysics Data System (ADS)

    Caussyn, D. D.; Baiod, R.; Blinov, B. B.; Chu, C. M.; Courant, E. D.; Crandell, D. A.; Derbenev, Ya. S.; Ellison, T. J. P.; Kaufman, W. A.; Krisch, A. D.; Lee, S. Y.; Minty, M. G.; Nurushev, T. S.; Ohmori, C.; Phelps, R. A.; Raczkowski, D. B.; Ratner, L. G.; Schwandt, P.; Stephenson, E. J.; Sperisen, F.; Przewoski, B. von; Wienands, U.; Wong, V. K.

    1995-09-01

    We recently studied the first acceleration of a spin-polarized proton beam through a depolarizing resonance using a partial Siberian snake. We accelerated polarized protons from 95 to 140 MeV with a constant 10% partial Siberian snake obtained using rampable solenoids. The 10% partial snake suppressed all observable depolarization during acceleration due to the Gγ=2 imperfection depolarizing resonance which occurred near 108 MeV. However, 20% and 30% partial Siberian snakes apparently moved an intrinsic depolarizing resonance, normally near 177 MeV, into our energy range; this caused some interesting, although not-yet-fully understood, depolarization.

  14. Review of geology of the New Siberian Islands between the Laptev and the East Siberian Seas, North East Russia

    NASA Astrophysics Data System (ADS)

    Kos'ko, M.; Korago, E.

    2009-09-01

    The New Siberian Islands comprise De Long Islands, Anjou Islands, and Lyakhov Islands. Early Paleozoic, Mesozoic and Cenozoic sediments and igneous rocks are known on the De Long Islands. Cambrian slate, siltstone, mudstone and silicified limestone occur on Bennett Island. Ordovician volcanogenic turbidites, lavas, and small intrusions of andesite-basalt, basalt, dolerite, and porphyritic diorite were mapped on Henrietta Island. The igneous rocks are of calc-alkaline island arc series. The Ordovician age of the sequence was defined radiometrically. Early Paleozoic strata were faulted and folded presumably in the Caledonian time. Early Cretaceous sandstone and mudstone are known on Bennett Island. They are overlain by a 106-124 Ma basalt unit. Cenozoic volcanics are widespread on the De Long Islands. Zhokhov Island is an eroded stratovolcano. The volcanics are mostly of picrite-olivine type and limburgite. Radiometric dating indicates Miocene to Recent ages for Cenozoic volcanism. On the Anjou islands Lower-Middle Paleozoic strata consist of carbonates, siliciclastics, and clay. A Northwest-southeast syn-sedimentary facies zonation has been reconstructed. Upper Paleozoic strata are marine carbonate, clay and siliciclastic facies. Mudstone and clay predominate in the Triassic to Upper Jurassic section. Aptian-Albian coal bearing deposits uconformably overlap lower strata indicating Early Cretaceous tectonism. Upper Cretaceous units are mostly clay and siltstone with brown coal strata resting on Early Cretaceous weathered rhyolite. Cenozoic marine and nonmarine silisiclastics and clay rest upon the older units with a transgressive unconformity including a weathering profile in the older rocks. Manifestations of Paleozoic and Triassic mafic and Cretaceous acidic magmatism are also found on these islands. The pre-Cretaceous structure of the Anjou islands is of a block and fold type Late Cimmerian in age followed by faulting in Cenozoic time. The Lyakhov islands are

  15. Reversion in Hamster Cells Transformed by Rous Sarcoma Virus.

    PubMed

    Macpherson, I

    1965-06-25

    Hamster cells of the BHK-21 line are transformable by Rous sarcoma virus (Schmidt-Ruppin strain). The transformed cells form colonies in agar suspension culture, grow on glass in disarray, and initiate tumors in hamsters and chickens, but extracts do not induce tumors in chickens. Chickens bearing tumors develop neutralizing antibody against the virus. Transformed cell clones give rise to "revertants" which form colonies on glass with cells oriented parallel to each other like the original uninfected cells. These revertants do not grow in agar or initiate chicken tumors, and they regain the original low transplantability of untransformed cells in hamsters.

  16. Pulmonary function in normal and elastase-treated hamsters exposed to a complex mixture of olefin-ozone-sulfur dioxide reaction products

    SciTech Connect

    Raub, J.A.; Miller, F.J.; Graham, J.A.; Gardner, D.E.; O'Neil, J.J.

    1983-01-01

    An elastase-induced emphysema model was utilized to determine if hamsters with preexisting lung disease were more susceptible to lung damage from air-pollutant exposure. Male golden hamsters, divided into two treatment groups, were given a single intratracheal injection of either 6 units of porcine pancreatic elastase (EMP) or buffer (CNT). After a 4-week recovery period, equal numbers of each group were exposed 23 hr/day x 28 day to filtered air (AIR) or to the complex by-products from a dark-phase-reaction mixture of trans-2-butene, ozone, and sulfur dioxide (MIX). Lung-function measurements on the elastase-treated groups showed changes consistent with mild emphysema. There were no significant differences in lung volumes or lung compliance between the AIR- and MIX-exposed animals. However, the nitrogen washout slope decreased and the diffusing capacity for carbon monoxide increased in both the CNT and EMP hamsters exposed to the MIX. The change in diffusing capacity was greater in normal hamsters than in hamsters with emphysema, and it is hypothesized that animals with impaired lung function had a decreased ability to respond to a pulmonary insult from the mix.

  17. T-lymphocyte-rich Thymoma and Myasthenia Gravis in a Siberian Tiger (Panthera tigris altaica)☆

    PubMed Central

    Allan, K.; Masters, N.; Rivers, S.; Berry, K.; Routh, A.; Lamm, C.

    2014-01-01

    Summary A 10-year-old captive male Siberian tiger (Panthera tigris altaica) presented with acute onset collapse, vomiting and dyspnoea, preceded by a 6-month period of progressive muscle wasting. Following humane destruction, post-mortem examination revealed a large multilobulated mass in the cranial mediastinum, which was diagnosed as a T-lymphocyte-rich thymoma with the aid of immunohistochemistry. Retrospective serology for acetylcholine receptor antibodies (titre 3.90 nmol/l) confirmed a diagnosis of thymoma-associated myasthenia gravis. Thymomas are reported rarely in wild carnivores, but when detected they appear to be similar in morphology to those seen in domestic carnivores and may also be accompanied by paraneoplastic syndromes. The clinical signs of myasthenia gravis in the tiger were consistent with those reported in cats and dogs and the condition is proposed as an important differential diagnosis for generalized weakness in captive Felidae. PMID:24444818

  18. The medial preoptic area is necessary for sexual odor preference, but not sexual solicitation, in female Syrian hamsters.

    PubMed

    Martinez, Luis A; Petrulis, Aras

    2013-04-01

    Precopulatory behaviors that are preferentially directed towards opposite-sex conspecifics are critical for successful reproduction, particularly in species wherein the sexes live in isolation, such as Syrian hamsters (Mesocricetus auratus). In females, these behaviors include sexual odor preference and vaginal scent marking. The neural regulation of precopulatory behaviors is thought to involve a network of forebrain areas that includes the medial amygdala (MA), the bed nucleus of the stria terminalis (BNST), and the medial preoptic area (MPOA). Although MA and BNST are necessary for sexual odor preference and preferential vaginal marking to male odors, respectively, the role of MPOA in odor-guided female precopulatory behaviors is not well understood. To address this issue, female Syrian hamsters with bilateral, excitotoxic lesions of MPOA (MPOA-X) or sham lesions (SHAM) were tested for sexual odor investigation, scent marking, and lordosis. MPOA-X females did not investigate male odors more than female odors in an odor preference test, indicating that MPOA may be necessary for normal sexual odor preference in female hamsters. This loss of preference cannot be attributed to a sensory deficit, since MPOA-X females successfully discriminated male odors from female odors during an odor discrimination test. Surprisingly, no deficits in vaginal scent marking were observed in MPOA-X females, although these females did exhibit decreased overall levels of flank marking compared to SHAM females. Finally, all MPOA-X females exhibited lordosis appropriately. These results suggest that MPOA plays a critical role in the neural regulation of certain aspects of odor-guided precopulatory behaviors in female Syrian hamsters.

  19. Effects of microinjections of substance P into the suprachiasmatic nucleus region on hamster wheel-running rhythms.

    PubMed

    Piggins, H D; Rusak, B

    1997-01-01

    The suprachiasmatic nucleus (SCN) receives a direct retinal projection, which in rats includes substance P (SP)-immunoreactive retinal ganglion cells. While SP has been shown to have neurophysiological effects on SCN cells in Syrian hamsters and rats, it is not known what effects SP in the SCN has on circadian rhythms in hamsters. We examined this question using male Syrian hamsters that were implanted with cannulas aimed at the SCN region and maintained in constant dim red lighting conditions. Hamsters received 0.5 microl microinjections of saline or SP (500 pmol in saline) at a variety of circadian times (CT). Saline injections had little or no phase-shifting effects at any phase tested. SP had no significant effects at CT4-8, 16-20, or 20-24, but did cause small phase delays of -23.7 +/- 7 min (mean +/- sem) at CT12-16. In order to examine the dose-response relations of this effect, hamsters were also microinjected with 50 and 2500 pmol of SP at CT12-16. Both the 50 and 2500 pmol doses induced very small phase delays (-14.2 +/- 7 min and -18.2 +/- 5 min, respectively), indicating no obvious dose dependence within this range. These results do not suggest that SP alone in the SCN mimics light effects on circadian rhythms or is a key neurotransmitter involved in photic entrainment. It remains to be determined whether SP interacts with other transmitters in the SCN to modulate their effects on rhythm phase.

  20. Simultaneous Occurrence of Pancreatic Adenocarcinoma and Brunner's Gland Adenoma in a Siberian Tiger (Panthera tigris altaica).

    PubMed

    Gombač, M; Dolenšek, T; Jaušovec, D; Kvapil, P; Švara, T; Pogačnik, M

    2015-11-01

    We describe a case of pancreatic adenocarcinoma and Brunner's gland adenoma in an 18-year-old male Siberian tiger (Panthera tigris altaica) from the Ljubljana Zoo. The tiger was humanely destroyed due to weakness and progressive weight loss. Necropsy examination revealed a large, grey, predominantly necrotic mass replacing the major part of the pancreatic body. Microscopically, the mass was unencapsulated, poorly demarcated, highly cellular and composed of highly pleomorphic, cuboidal to tall columnar cells with basal, round or oval, moderately anisokaryotic nuclei with prominent nucleoli and moderate to large amounts of eosinophilic cytoplasm. The tumour was diagnosed as pancreatic tubular adenocarcinoma with infiltration into the duodenum and mesentery. There were tumour emboli in mesenteric blood vessels and hepatic metastases. The non-affected part of the pancreas exhibited severe chronic pancreatitis. In addition, one firm white neoplastic nodule was observed in the duodenal wall. The nodule was set in the tunica muscularis and was unencapsulated, well demarcated and highly cellular, and consisted of a closely packed layer of normal Brunner's glands and a centrally positioned group of irregularly branched tubules with small amounts of debris in the lumen. The neoplastic nodule was diagnosed as Brunner's gland adenoma. The present case is, to the best of our knowledge, the first report of concurrent pancreatic adenocarcinoma and Brunner's gland adenoma, most probably induced by chronic pancreatitis, either in man or animals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Ezetimibe ameliorates intestinal chylomicron overproduction and improves glucose tolerance in a diet-induced hamster model of insulin resistance

    PubMed Central

    Naples, Mark; Baker, Chris; Lino, Marsel; Iqbal, Jahangir; Hussain, M. Mahmood

    2012-01-01

    Ezetimibe is a cholesterol uptake inhibitor that targets the Niemann-Pick C1-like 1 cholesterol transporter. Ezetimibe treatment has been shown to cause significant decreases in plasma cholesterol levels in patients with hypercholesterolemia and familial hypercholesterolemia. A recent study in humans has shown that ezetimibe can decrease the release of atherogenic postprandial intestinal lipoproteins. In the present study, we evaluated the mechanisms by which ezetimibe treatment can lower postprandial apoB48-containing chylomicron particles, using a hyperlipidemic and insulin-resistant hamster model fed a diet rich in fructose and fat (the FF diet) and fructose, fat, and cholesterol (the FFC diet). Male Syrian Golden hamsters were fed either chow or the FF or FFC diet ± ezetimibe for 2 wk. After 2 wk, chylomicron production was assessed following intravenous triton infusion. Tissues were then collected and analyzed for protein and mRNA content. FFC-fed hamsters treated with ezetimibe showed improved glucose tolerance, decreased fasting insulin levels, and markedly reduced circulating levels of TG and cholesterol in both the LDL and VLDL fractions. Examination of triglyceride (TG)-rich lipoprotein (TRL) fractions showed that ezetimibe treatment reduced postprandial cholesterol content in TRL lipoproteins as well as reducing apoB48 content. Although ezetimibe did not decrease TRL-TG levels in FFC hamsters, ezetimibe treatment in FF hamsters resulted in decreases in TRL-TG. Jejunal apoB48 protein expression was lower in ezetimibe-treated hamsters. Reductions in jejunal protein levels of scavenger receptor type B-1 (SRB-1) and fatty acid transport protein 4 were also observed. In addition, ezetimibe-treated hamsters showed significantly lower jejunal mRNA expression of a number of genes involved in lipid synthesis and transport, including srebp-1c, sr-b1, ppar-γ, and abcg1. These data suggest that treatment with ezetimibe not only inhibits cholesterol uptake, but may

  2. Natural infection of Cryptosporidium muris (Apicomplexa: Cryptosporiidae) in Siberian chipmunks.

    PubMed

    Hůrková, Lada; Hajdusek, Ondrej; Modrý, David

    2003-04-01

    Coprologic examination of nine Siberian chipmunks (Eutamias sibiricus) imported from Southeast Asia revealed infection with Cryptosporidium sp. Experimental inoculation of BALB/c mice proved their susceptibility to the infection. Infected mice shed oocysts 14-35 days postinfection. Oocyst morphology was similar to that reported for C. muris in previous studies, oocysts were 8.1 (7.0-9.0) x 5.9 (5.0-6.5) microns. Clinical signs were absent in naturally infected chipmunks and experimental mice. Histologic examinations of mice revealed numerous developmental stages of C. muris in the glandular stomach. Analysis of partial small subunit rRNA gene sequences confirmed identity of these isolates as C. muris. Our results represent the first report of C. muris in members of the family Sciuridae.

  3. [Winter distribution of birds in the West Siberian Plain].

    PubMed

    Vartepov, L G; Livanov, S G; Tsybulin, S M; Evsiukov, A K

    2005-01-01

    Long-term studies on the winter population of birds in the West Siberian Plain on a landscape basis allowed us to reveal the regional and seasonal patterns of their distribution. The highest proportion of species demonstrated forest-steppe and forest preference, while the lowest proportion demonstrated aquatic-semiaquatic and tundra-forest-tundra preference. The preference zones did not change or extend in the winter period relative to summer postnesting period only in a small fraction of species; while the preference zones of most species were reduced or shifted. Commonly, the zonal borders of preferred habitats shifted southward to better climatic, feeding, and safety conditions. Only rare species with seasonally changing and specialized feeding demonstrated a northward shift of these borders.

  4. West Siberian oil production in the mid-1990s

    SciTech Connect

    Sagers, M.J.

    1994-11-01

    A Western specialist on the liquid fuel industries and resources of Russia surveys trends in and factors affecting output in Russia`s most important oil-producing region, accounting for nearly 70% of the country`s production in 1994 and a similar share of oil reserves. A prolonged decline in oil output in the region, starting in 1988, appears to be bottoming out as a function of efforts to rehabilitate idle wells and liberalized regulations governing oil exports. A focus is on documenting trends in production within a series of region production associations charged with operation of specific fields (of widely variable age and reserves) in West Siberia and on surveying Western participation in joint ventures involved in field development for deposits characterized by difficult conditions. Official projections of West Siberian crude oil output based on various assumptions regarding rates of investment, well rehabilitation, exploratory drilling, secondary recovery, etc. are reviewed and evaluated. 21 refs., 1 fig., 3 tabs.

  5. Hydrooptical characteristics of the Laptev and East-Siberian Seas

    NASA Astrophysics Data System (ADS)

    Makshtas, A.; Vlasenkov, R.

    2009-04-01

    Based on the data of experimental investigations executed in open waters of the East - Siberian and Laptev Seas on the board of research vessel "Ivan Petrov" in 2003 and 2004, the empirical dependences between intensity of global short-wave radiation, concentration of suspended matter and depth of Secchi disk disappearance have been developed. Spectral measurements of penetrated to different depths solar radiation, carried out for the first time in the area under study, have allowed to estimate and, as a first approximation, to develop the empirical ratio between intensity of global solar radiation and PAR radiation in dependence on concentration of suspended matter. The long-term temporal-spatial variability of turbidity, PAR attenuation coefficients, and suspended materials concentration in 1950s - 1980s in comparison with measured ones in 1998 - 2007 is investigated with dataset of historical Secchi disc data, obtained during Russian Ice Patrol expeditions.

  6. [Operation on a congenital cataract in a Siberian Tiger].

    PubMed

    Seitz, R; Weisse, I

    1979-01-01

    A cataract operation in a young Siberian tiger is reported. This 5-month-old tiger, presenting with blindness, showed bilateral residual pupillary membranes and anterior polar cataracts combined with nuclear cataracts. After unilateral intracapsular extraction of the lens, the tiger adapted well to the improvement in sight and behaved almost like an animal with normal vision. The animal died 3 months post-operatively from unknown cause. Histological examination of the aphakic eye showed, at the site of operation on the cornea, an intact epithelium with discrete infiltration of the stroma together with low-grade vascularisation. In the eye not treated operatively, both an anterior polar cataract with adherent pupillary membrane strands and a central cataract were seen. Of particular note, when comparing this large wild cat with the domestic cat, was the marked development of the tapetum lucidum (up to 30 cell layers).

  7. Oil and gas resources in the West Siberian Basin, Russia

    SciTech Connect

    1997-12-01

    The primary objective of this study is to assess the oil and gas potential of the West Siberian Basin of Russia. The study does not analyze the costs or technology necessary to achieve the estimates of the ultimate recoverable oil and gas. This study uses reservoir data to estimate recoverable oil and gas quantities which were aggregated to the field level. Field totals were summed to a basin total for discovered fields. An estimate of undiscovered oil and gas, from work of the US Geological Survey (USGS), was added to give a total basin resource volume. Recent production decline points out Russia`s need to continue development of its discovered recoverable oil and gas. Continued exploration is required to discover additional oil and gas that remains undiscovered in the basin.

  8. Petroleum geology and resources of the West Siberian Basin, Russia

    USGS Publications Warehouse

    Ulmishek, Gregory F.

    2003-01-01

    The West Siberian basin is the largest petroleum basin in the world covering an area of about 2.2 million km2. The basin occupies a swampy plain between the Ural Mountains and the Yenisey River. On the north, the basin extends offshore into the southern Kara Sea. On the west, north, and east, the basin is surrounded by the Ural, Yenisey Ridge, and Turukhan-Igarka foldbelts that experienced major deformations during the Hercynian tectonic event and the Novaya Zemlya foldbelt that was deformed in early Cimmerian (Triassic) time. On the south, the folded Caledonian structures of the Central Kazakhstan and Altay-Sayan regions dip northward beneath the basin?s sedimentary cover. The basin is a relatively undeformed Mesozoic sag that overlies the Hercynian accreted terrane and the Early Triassic rift system. The basement is composed of foldbelts that were deformed in Late Carboniferous?Permian time during collision of the Siberian and Kazakhstan continents with the Russian craton. The basement also includes several microcontinental blocks with a relatively undeformed Paleozoic sedimentary sequence. The sedimentary succession of the basin is composed of Middle Triassic through Tertiary clastic rocks. The lower part of this succession is present only in the northern part of the basin; southward, progressively younger strata onlap the basement, so that in the southern areas the basement is overlain by Toarcian and younger rocks. The important stage in tectono-stratigraphic development of the basin was formation of a deep-water sea in Volgian?early Berriasian time. The sea covered more than one million km2 in the central basin area. Highly organic-rich siliceous shales of the Bazhenov Formation were deposited during this time in anoxic conditions on the sea bottom. Rocks of this formation have generated more than 80 percent of West Siberian oil reserves and probably a substantial part of its gas reserves. The deep-water basin was filled by prograding clastic clinoforms

  9. The Cambrian of Bennett Island (New Siberian Islands)

    NASA Astrophysics Data System (ADS)

    Danukalova, M. K.; Kuzmichev, A. B.; Korovnikov, I. V.

    2014-07-01

    The paper presents new data on the Cambrian stratigraphy of Bennett Island, one of the least explored East Arctic islands. The section, about 500 m of total thickness, comprises four lithological units that store a record of the deposition history: (1) clastic sediments including storm sandstones; (2) shallow-marine mudstone; (3) lagoonal variegated mudstone and limestone; (4) black shale. It is suggested to classify the units as formations with their proper names. The section spans all epoches of the Cambrian stratigraphy constrained by trilobite fossils. In the Cambrian, territory of the island belonged to Siberia rather than to some exotic terrane, judging by abundant endemic Siberian trilobite species in the Bennett section. This inference is supported by synchronicity in recorded deposition events of Bennett Island and northeastern Siberia (Kharaulakh Mountains). The Cambrian sediments of the two areas were deposited in different parts of a single shallow sea which extended as far as Taimyr.

  10. A role for glucose in hypothermic hamsters

    NASA Technical Reports Server (NTRS)

    Resch, G. E.; Musacchia, X. J.

    1976-01-01

    Hypothermic hamsters at a rectal temperature of 7 C showed a fivefold increase in survival times from 20 to 100.5 hr when infused with glucose which maintained a blood level at about 45 mg/100 ml. A potential role for osmotic effects of the infusion was tested and eliminated. There was no improvement in survival of 3-O-methylglucose or dextran 40-infused animals. The fact that death eventually occurs even in the glucose-infused animal after about 4 days and that oxygen consumption undergoes a slow decrement in that period suggests that hypothermic survival is not wholly substrate limited. Radioactive tracer showed that localization of the C-14 was greatest in brain tissue and diaphragm, intermediate in heart and kidney, and lowest in skeletal muscle and liver. The significance of the label at sites important to respiration and circulation was presented.

  11. A role for glucose in hypothermic hamsters

    NASA Technical Reports Server (NTRS)

    Resch, G. E.; Musacchia, X. J.

    1976-01-01

    Hypothermic hamsters at a rectal temperature of 7 C showed a fivefold increase in survival times from 20 to 100.5 hr when infused with glucose which maintained a blood level at about 45 mg/100 ml. A potential role for osmotic effects of the infusion was tested and eliminated. There was no improvement in survival of 3-O-methylglucose or dextran 40-infused animals. The fact that death eventually occurs even in the glucose-infused animal after about 4 days and that oxygen consumption undergoes a slow decrement in that period suggests that hypothermic survival is not wholly substrate limited. Radioactive tracer showed that localization of the C-14 was greatest in brain tissue and diaphragm, intermediate in heart and kidney, and lowest in skeletal muscle and liver. The significance of the label at sites important to respiration and circulation was presented.

  12. Effect of chronic treatment with bovine recombinant growth hormone on cardiac dysfunction and lesion progression in UM-X7.1 cardiomyopathic hamsters.

    PubMed

    Marleau, Sylvie; Lapointe, Nathalie; Massicotte, Julie; Céméus, Catia; Jasmin, Gaëtan; Dumont, Louis; Sirois, Martin G; Rouleau, Jean-Lucien; Du Souich, Patrick; Ong, Huy

    2002-12-01

    In view of the potentially beneficial effect of GH on ventricular function of humans suffering from idiopathic dilated cardiomyopathy, we undertook a study to evaluate the optimal time to initiate treatment with GH and its duration in UM-X7.1 cardiomyopathic hamsters (CMH). GH (1 mg/kg.d) therapy was initiated either in the early or late (30 and 160 d old, respectively) phases of the disease and continued until death at 240 d of age. Age- and sex-matched Golden Syrian hamsters (GSH) were used as controls. Basal IGF-1 levels in serum were reduced by nearly half in CMH compared with GSH but were increased within a physiological range in male hamsters. In contrast, female hamsters presented elevated basal serum IGF-1 levels that were not further elevated by GH administration, as reported in experimental models and humans. Accordingly, the present study will focus on the effects of GH therapy on cardiac performance in male hamsters. GH did not improve ventricular function when starting at a late stage of the disease compared with CMH controls. Maximum rate of left ventricular pressure development decreased by approximately 64% in CMH treated early with recombinant bovine GH. Ventricular dysfunction was associated with morphologic indices of hypertrophy, ventricular dilatation, and extensive fibrosis. Mortality was strikingly increased in GH-treated CMH for 210 d (four males and eight females), as opposed to four females (and no male) in the vehicle-treated group. These results suggest that chronic treatment with recombinant bovine GH in CMH, starting at an early stage of lesion development, is associated with a reduced cardiac performance at the terminal stage of the disease.

  13. Contact Metamorphic Halocarbon Production in the Siberian Traps

    NASA Astrophysics Data System (ADS)

    Fristad, K. E.; Schmidbauer, N.; Svensen, H.; Polozov, A. G.; Planke, S.

    2012-12-01

    The Siberian Trap flood basalts erupted into and through the Siberian craton around 252 million years ago and emplaced sill intrusions up to hundreds of meters thick into hydrocarbon-bearing evaporite deposits of the Tunguska Basin in Eastern Siberia. Large volumes of carbon gases are hypothesized to have been produced in the aureoles around these intrusions leading to build-up and catastrophic release of toxic greenhouse gases to the end-Permian atmosphere. The crustal volatiles released through this process are believed to have contributed to environmental crisis and the end-Permian mass extinction. We have conducted a series of laboratory pyrolysis experiments on hydrocarbon-bearing Tunguska Basin evaporite samples in order to assess the composition and quantity of volatile compounds generated during contact metamorphic heating of this rock. The experiments were conducted on natural samples from a drill core at approximately 850 meters depth at Nepa in Siberia and span approximately 140 meters of evaporitic country rock around a 40 meter thick sill intrusion. The mineralogy of the samples is predominantly halite and anhydrite and the samples span the range of thermal conditions experienced in the aureole after the sill emplacement event. Using a mill/heating cell coupled to a Medusa gas chromatograph mass spectrometer, we measured the volatile content of the fluid inclusions as well as the volatiles produced by heating of the samples. Sample heating produced a spectrum of carbon-, fluorine-, and chlorine-bearing gases in concentrations orders of magnitude higher than that found in the fluid inclusions and in the modern atmosphere. Our experimental results illustrate the significance of contact metamorphism for toxic gas production, including halocarbons, in the Tunguska Basin sediments at the end-Permian.

  14. Asynchronous population dynamics of Siberian lemmings across the Palaearctic tundra.

    PubMed

    Erlinge, Sam; Danell, Kjell; Frodin, Peter; Hasselquist, Dennis; Nilsson, Patric; Olofsson, Eva-Britt; Svensson, Mikael

    1999-06-01

    The synchrony of Siberian lemming (Lemmus sibiricus L.) population dynamics was investigated during a ship-borne expedition along the Palaearctic tundra coast in the summer of 1994. On 12 sites along the coast from the Kola Peninsula to Wrangel Island, relative densities of lemmings were recorded using a standardised snap-trapping programme. The phase position of the lemming cycle in each of the studied populations was determined based on current density estimates, signs of previous density and the age profile of each population (ageing based on eye lens mass). In addition, dendrochronological methods were used to determine when the last peak in the density of microtine populations occurred at each site. The examined lemming populations were in different phases of the lemming cycle. Some populations were in the peak phase, as indicated by high current densities, an age profile in which older individuals were well represented, and signs of high previous density (abundant old lemming faeces). Other populations were in the decline phase, as reflected in a moderate current density, a predominance of older individuals and signs of high previous density. Populations in the low phase had an extremely low current density and showed signs of high previous density, while populations in the increase phase had a moderate current density, a predominance of younger individuals and showed signs of low previous density. The results of phase determinations based on dendrochronological methods support the findings based on lemming demography. Recent Russian studies carried out on some of the sites also agreed with our phase determination results. Thus, on a regional scale (across the whole Palaearctic tundra), the population dynamics of Siberian lemmings can be considered asynchronous. However, sites situated adjacent to each other were often phase synchronous, suggesting a more fine-grained pattern of dynamics with synchrony over distances as long as 1000 km or so, e.g. the Yamal

  15. [Seasonal development of phloem in Siberian larch stems].

    PubMed

    Antonova, G F; Stasova, V V

    2008-01-01

    The seasonal development of phloem in the stems of Siberian larch (Larix sibirica Ldb.) was studied over two seasons on 50-60-year-old trees growing in a natural stand in the Siberian forest-steppe zone. Trees at the age of 20-25 years were used to study metabolites in differentiating and mature phloem elements, cambial zone, and radially growing xylem cells in the period of early and late wood formation. The development of the current-year phloem in the stems of 50-60-year-old trees started, depending on climatic conditions, in the second-third decades of May, 10-20 days before the xylem formation, and ended together with the shoot growth cessation in late July. Monitoring of the seasonal activity of cambium producing phloem sieve cells and the duration of their differentiation compared to the xylem derivatives in the cambium demonstrated that the top production of phloem and xylem cells could coincide or not coincide during the season, while their differentiation activity was always in antiphase. Sieve cells in the early phloem are separated from those in the late phloem by a layer of tannin-containing cells, which are formed in the period when late xylem formation starts. The starch content in the structural elements of phloem depends on the state of annual xylem layer development. The content of low molecular weight carbohydrates, amino acids, organic acids, and phenols in phloem cells, cambial zone, and xylem derivatives of the cambium depends on the cell type and developmental stage as well as on the type of forming wood (early or late) differing by the cell wall parameters and, hence, by the requirement for assimilates. Significant differences in the dynamics of substances per dry weight and cell were observed during cell development.

  16. Hydrocarbon potential of hydrocarbon source rocks of the New Siberian Islands, Russian Arctic

    NASA Astrophysics Data System (ADS)

    Gaedicke, Christoph; Sobolev, Peter; Franke, Dieter; Piepjohn, Karsten; Brandes, Christian; Kus, Jolanta; Scheeder, Georg

    2016-04-01

    The New Siberian Islands are bridging the Laptev Sea with the East Siberian Sea. The Laptev and East Siberian Seas cover large areas of the continental margin of northeastern Arctic Russia. The East Siberian Shelf encompassing an area of 935.000 km2 is still virtually unexplored and most of the geological models for this shelf are extrapolations of the geology of the New Siberian Islands, the Wrangel Island and the northeast Siberian landmass. Apart from few seismic reflection lines, airborne magnetic data were the primary means of deciphering the structural pattern of the East Siberian Shelf. The Laptev Shelf covers an area of about 66.000 km2 and occupies a shelf region, where the active mid-oceanic spreading ridge of the Eurasian Basin hits the slope of the continental margin. During the joint VSEGEI/BGR field expedition CASE 13 (Circum Arctic Structural Events) in summer 2011 we sampled outcrops from the New Siberian Archipelago including the De Long Islands. 102 samples were collected and the Upper Palaeozoic to Lower Cenozoic units are found to be punctuated by several organic-rich intervals. Lithology varies from continental dominated clastic sedimentary rocks with coal seams to shallow marine carbonates and deep marine black shales. Rock-Eval pyrolysis, gas chromatography/mass spectrometry and organic petrography studies were performed to estimate organic matter contents, composition, source, and thermal maturity. According to the results of our analyses, samples from several intervals may be regarded as potential petroleum source rocks. The Lower Devonian shales have the highest source rock potential of all Paleozoic units. Triassic samples have a good natural gas potential. Cretaceous and Cenozoic low-rank coals, lignites, and coal-bearing sandstones display some gas potential. The kerogen of type III (humic, gas-prone) dominates. Most of the samples (except some of Cretaceous and Paleogene age) reached the oil generation window.

  17. A key Paleozoic section in the northern part of the Western Siberian Region

    NASA Astrophysics Data System (ADS)

    Chuvashov, B. I.; Bochkarev, V. S.

    2016-05-01

    A few of our predecessors considered the Eastern Siberian Region to be a huge territory with similar geological history without hydrocarbon prospecting opportunities. It was also proposed to search for oil and gas in the seas of the Arctic Ocean. Not denying these search directions, we have offered to explore the Western Siberian Region by analysis of numerous deep wells, variable facial zones of Paleozoic complexes, and real prospects of searching for oil and gas fields.

  18. Neural mechanisms of individual and sexual recognition in Syrian hamsters (Mesocricetus auratus).

    PubMed

    Petrulis, Aras

    2009-06-25

    Recognizing the individual and sexual identities of conspecifics is critical for adaptive social behavior and, in most mammals this information is communicated primarily by chemosensory cues. Due to its heavy reliance on odor cues, we have used the Syrian hamster as our model species for investigating the neural regulation of social recognition. Using lesion, electrophysiological and immunocytochemical techniques, separate neural pathways underlying recognition of individual odors and guidance of sex-typical responses to opposite-sex odors have been identified in both male and female hamsters. Specifically, we have found that recognition of individual odor identity requires olfactory bulb connections to entorhinal cortex (ENT) rather than other chemoreceptive brain regions. This kind of social memory does not appear to require the hippocampus and may, instead, depend on ENT connections with piriform cortex. In contrast, sexual recognition, through either differential investigation or scent marking toward opposite-sex odors, depends on both olfactory and vomeronasal system input to the corticomedial amygdala. Preference for investigating opposite-sex odors requires primarily olfactory input to the medial amygdala (ME) whereas appropriately targeted scent marking responses require vomeronasal input to ME as well as to other structures. Within the ME, the anterior section (MEa) appears important for evaluating or classifying social odors whereas the posterodorsal region (MEpd) may be more involved in generating approach to social odors. Evidence is presented that analysis of social odors may initially be done in MEa and then communicated to MEpd, perhaps through micro-circuits that separately process male and female odors.

  19. Evidence for a metabolic limitation of survival in hypothermic hamsters.

    NASA Technical Reports Server (NTRS)

    Prewitt, R. L.; Anderson, G. L.; Musacchia, X. J.

    1972-01-01

    The underlying factors limiting survival in the hypothermic state are studied. Hamsters of both sexes, clipped and unclipped, were inducted into profound hypothermia by the helium cold method until they reached a temperature between 7 and 10 C. It appears that the primary cause of death is failure of respiration due to the depletion of carbohydrate energy supplies and may explain why survival time in hypothermia is shorter than the normal hibernation time of the hamster.

  20. 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.

  1. Development of survival skills in captive-raised Siberian polecats (Mustela eversmanni) I: locating prey

    USGS Publications Warehouse

    Miller, Brian; Biggins, Dean; Wemmer, Chris; Powell, Roger; Hanebury, Lou; Horn, Deborah; Vargas, Astrid

    1990-01-01

    Captive-raised mustelids appear to have a rudimentary capacity to kill prey, but the skills necessary for locating prey may be eroded during captivity. We tested the maturational component of prey-searching behavior with captive-raised Siberian polecats (Mustela eversmanni) by subjecting polecats to a simulated prairie dog colony of 6 burrows within a 200 m2 arena. Ten naive Siberian polecats at ages 2.5, 3.5, and 4.5 months (30 total) were deprived of food for 12 hours. A dead prairie dog was placed in 1 prairie dog burrow and the other 5 were empty. A single Siberian polecat was released onto the colony shortly before sunset and its movements monitored from an observation tower. Older Siberian polecats located prey significantly quicker than younger polecats, but all age groups spent a great deal of time in surface activity not directed toward a burrow. When Siberian polecats were about 10 months old, all burrows in the arena were plugged with dirt including the burrow with the prairie dog. In this winter test, Siberian polecats located the prey but still spent a great deal of time in non-burrow directed surface activity. Economical use of surface time, with a low amount of non-burrow directed behavior, would presumably reduce the risk of predation for hunting polecats.

  2. Differential effects of glucocorticoids on energy homeostasis in Syrian hamsters.

    PubMed

    Solomon, Matia B; Sakai, Randall R; Woods, Stephen C; Foster, Michelle T

    2011-08-01

    Syrian hamsters, like many humans, increase food intake and body adiposity in response to stress. We hypothesized that glucocorticoids (cortisol and corticosterone) mediate these stress-induced effects on energy homeostasis. Because Syrian hamsters are dual secretors of cortisol and corticosterone, differential effects of each glucocorticoid on energy homeostasis were investigated. First, adrenal intact hamsters were injected with varying physiological concentrations of cortisol, corticosterone, or vehicle to emulate our previously published defeat regimens (i.e., 1 injection/day for 5 days). Neither food intake nor body weight was altered following glucocorticoid injections. Therefore, we investigated the effect of sustained glucocorticoid exposure on energy homeostasis. This was accomplished by implanting hamsters with supraphysiological steady-state pellets of cortisol, corticosterone, or cholesterol as a control. Cortisol, but not corticosterone, significantly decreased food intake, body mass, and lean and fat tissue compared with controls. Despite decreases in body mass and adiposity, cortisol significantly increased circulating free fatty acids, triglyceride, cholesterol, and hepatic triglyceride concentrations. Although corticosterone did not induce alterations in any of the aforementioned metabolic end points, Syrian hamsters were responsive to the effects of corticosterone since glucocorticoids both induced thymic involution and decreased adrenal mass. These findings indicate that cortisol is the more potent glucocorticoid in energy homeostasis in Syrian hamsters. However, the data suggest that cortisol alone does not mediate stress-induced increases in food intake or body mass in this species.

  3. Weather entrainment and multispectral diel activity rhythm of desert hamsters.

    PubMed

    Wan, Xinrong; Zhang, Xinjie; Huo, Yingjun; Wang, Guiming

    2013-10-01

    The circadian rhythm of animals is an adaptation to predictable variation in environmental conditions. Multiple internal oscillators may allow animals to cope with environmental oscillations in different frequencies. Heat stress and dramatic differences between night and day temperatures are the main selective pressures of the diel activity of desert mammals, particularly small-sized rodents. We tested the hypotheses that the diel activities of desert hamsters (Phodopus roborovskii) would be entrained by ambient humidity and temperature. We predicted that increases in night temperature and humidity would improve the propensity to perform activities of the hamster. We observed hourly activities of desert hamsters under semi natural conditions for 24 consecutive hours, with seven replicates in 7 different days. We fit generalized linear mixed models to observed proportions of active hamsters, temperatures, and relative humidity. Observed diel activities of desert hamsters consisted of three harmonic oscillations in the periodicities of 24 h, 12 h, and 6 h, respectively. Furthermore, probabilities to perform activities were positively related to night temperature and humidity. Therefore, the diel activities of desert hamsters are synchronized by atmospheric humidity, temperatures, and environmental cues of ultradian fluctuations.

  4. [Induction of protective antiamebic immunity in hamsters with heterologous antigens].

    PubMed

    Jiménez Cardoso, J M; Jiménez, E; de Jesús Bernal, M; Kumate, J

    1989-01-01

    Two hundred and twenty-five Syrian golden hamsters were used. Twenty five of them served as the control group. All other hamsters were intradermal immunized, once a week for four weeks, with a mixture of amebic proteins, mixed with complete Freund adjuvant, obtained from 5 x 10(5) homogenized dead amebic trophozoites from five different strains. Each group of hamsters (five groups of 40 animals each) were immunized with one of the following strains: E. histolytica HM-531, HJ-1, HM1-IMSS, E. chattoni PM-4 and PM-5. All hamsters, including those from the control group, were later inoculated with 0.2 mL equivalent to 1 x 10(5) live trophozoites from the different strains grown in axenic TYI-S-33 medium. Inoculation was performed by direct injection into the liver. The hamsters were sacrificed eight days later and their livers examined. All non-immunized animals showed extensive gross hepatic nodular abscesses. The liver of immunized hamsters showed mild to moderate lesions: the histopathological striking feature was non-specific granulomata. It is concluded that the immunized animals inoculated with homologous stock showed protective immunity to amebic infections. In other cases, immunity was seen though they were inoculated with a heterologous stock.

  5. Regulation of hamster splenocyte reactivity to concanavalin A during pregnancy

    SciTech Connect

    Weppner, W.A.; Coggin, J.H. Jr.

    1980-08-15

    The survival to term of mammalian fetuses regardless of their expression of paternal or embryonic developmental antigens suggests that some alteration in the immune capabilities of a female occur during pregnancy. The immunocompetence of female Syrian golden hamsters during pregnancy was investigated with respect to the blastogenic response of spleen cells to the T-cell mitogen concanavalin A (Con A). The blastogenic response of spleen cells from pregnant hamsters during mid- or late gestation is 10% of that observed for spleen cells from age-matched, virgin female animals. The spleen cells from pregnant hamsters are not capable of suppressing the proliferative response of spleen cells from virgin females to Con A. However, the serum from pregnant hamsters, in comparison with serum from virgin female animals, is capable of reducing this mitogenic response. Extensive washing of the splenocytes from pregnant hamsters does reduce the degree of suppression. These results suggest that the hamster is an excellent animal model for the investigation of the mechanism(s) of immune regulation that operate during pregnancy.

  6. Ocular pathological changes in hamsters experimentally infected with Schistosoma mansoni.

    PubMed

    Ismail, H I H; Ashour, D S; Abou Rayia, D M; Ali, A L

    2016-11-01

    Ocular lesions have been reported in patients with schistosomiasis; however, the problem with studying schistosomal infection of the human eye is that biopsies are almost impossible to take, and histopathological examination of suspicious lesions can only be undertaken post-mortem or after enucleation. This work aimed to study the possible effects and pathogenesis of schistosomiasis on the eye. This study involved 55 hamsters; five hamsters remained non-infected and the remaining 50 hamsters were infected with Schistosoma mansoni cercariae. Infected hamsters were sacrificed on weeks 8, 12, 16 and 20 post-infection (pi). Eye sections were prepared and stained for histopathological and immunohistochemical studies. Histopathological changes detected in hamsters infected after 16 and 20 weeks included looseness and oedema of the innermost retinal layers together with hyperplastic polypoid growth. Neither eggs nor granulomata were detected in eye sections throughout the experimental period. Deposition of S. mansoni antigen was revealed in 35% of infected hamsters. Later, on weeks 16 and 20 pi, moderate subepithelial conjuctival deposits and marked subchoroidal and scleral deposition were detected. In conclusion, the deposition of schistosomal antigen and immune complexes may play a pivotal role in the ocular changes that occur in schistosomiasis, even in the absence of detectable Schistosoma eggs. Schistosomiasis should be suspected in cases with unexplained ophthalmological findings, especially in endemic areas.

  7. Regulation of tonic gonadotropin release in prepubertal female hamsters

    SciTech Connect

    Smith, S.G.; Matt, K.S.; Prestowitz, W.F.; Stetson, M.H.

    1982-04-01

    Basal serum gonadotropin levels were monitored weekly in female hamsters from birth to 10 weeks of age. Hamsters raised on three different photoperiods presented uniform pre- and postpubertal patterns of serum LH and FSH, suggesting that gonadotropin release in the young hamster occurs independently of ambient photoperiod. In all groups, serum LH levels increased gradually in animals up to 4 weeks of age, after which levels plateaued at 50--100 ng/ml. Serum FSH was markedly elevated in 2- and 3-week-old hamsters (800--1200 ng/ml), but remained at 200--400 ng/ml in all other groups. We next examined the change in the responsiveness of the pituitary to exogenous gonadotropin-releasing hormone (GnRH) challenge. Female hamsters 2 days of age failed to respond to any dose (0.025--1000 ng) of GnRH, while 10-day old females responded in typical dose-dependent fashion. GnRH-stimulated LH release first occurred in 6-day-old hamsters and was maximal by day 9, whereas FSH release first occurred on day 8 and was maximal by day 9. The prepubertal pattern of gonadotropin release can, in part, be explained on the basis of the development of pituitary GnRH sensitivity, which occurs independently of photoperiod.

  8. Suppression of hamster lymphocyte reactivity to simian virus 40 tumor surface antigens by spleen cells from pregnant hamsters

    SciTech Connect

    Weppner, W.A.; Adkinson, L.R.; Coggin, J.H.Jr

    1980-09-01

    SV40-transformed tumor cells in hamsters have been found to have cell surface antigens cross-reactive with antigens temporally expressed on fetal tissues. Using a lymphocyte transformation assay, spleen cells from pregnant hamsters were found to be incapable of responding to preparations of either hamster fetal tissue or SV40-transformed cells. However, a suppressor component can be demonstrated in spleen cell populations of both primi-and multiparous hamsters during pregnancy that is capable of reducing the response of lymphocytes sensitized against SV40 tumor-associated antigens. The degree of suppression is proportional to the ratio of responder cells to spleen cells from pregnant animals. These results suggest there is a subpopulation of spleen cells involved in immunoregulation during pregnancy that has the ability to suppress the reactivity of lymphocytes sensitized against SV40-associated oncofetal antigens.

  9. Correlation of multi-channel seismic data from the Laptev and East Siberian Seas to onshore geology of the New Siberian Islands, Russian Arctic

    NASA Astrophysics Data System (ADS)

    Gaedicke, C.; Franke, D.; Piepjohn, K.; Brandes, C.; Sobolev, N.; Tolmacheva, T.; Mouly, B.

    2012-12-01

    The Laptev and East Siberian Seas cover large areas of the continental margin of North-Eastern Siberia and are separated by the New Siberian Islands. The East Siberian Shelf covering an area of 935.000 km2 is a virtually unexplored area and most geological models for this shelf are extrapolations of the geology of the New Siberian Islands, the Wrangel Island and the northeast Siberia landmass. Apart from few seismic reflection lines airborne magnetic data were the primary means of deciphering the structural pattern of the East Siberian Shelf. The Laptev Shelf covers an area of about 66.000 km2 and occupies a shelf region, where the active mid-oceanic spreading ridge meets the slope of a continental margin. Since no deep wells have been drilled so far on the shelves surrounding the New Siberian Islands, the precise age and nature of seismic horizons remain uncertain. All interpretations base on different evolution scenarios for the shelf areas resulting in a wide variety of interpretations available for the sedimentary cover of the Laptev Shelf where the interpretations range from Proterozoic to Cenozoic. During the joint VSEGEI/BGR field expedition CASE 13 (Circum Arctic Structural Events) in summer 2011 we sampled outcrops from the New Sibirian Archipelago including the DeLong Islands. Main purposes of the field work were: deciphering the structural evolution, paleo-stress analysis, stratigraphy and paleo-environmetal studies, and collection of potential hydrocarbon source rocks and host rocks. Here we present correlations from onshore to offshore based on multichannel reflection seismic data acquired by BGR in the 1990th and the field campaign CASE 13. Key marker horizons in the offshore data will be linked to major hiatuses in the onshore region. Well information is available close by the Lena delta in the form of sketched stratigraphy ranging from Proterozoic to Cretaceous. Both informations can be reconciled on a cross section despite a gap of approximately 25

  10. 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.

  11. Sex ratio adjustment by sex-specific maternal cannibalism in hamsters.

    PubMed

    Beery, Annaliese K; Zucker, Irving

    2012-10-10

    Mammalian offspring sex ratios can be biased via prenatal and postnatal mechanisms, including sperm selection, sex-specific embryo loss, and differential postnatal investment in males and females. Syrian hamsters routinely cannibalize some of their pups in the first days after birth. We present evidence that short day lengths, typically predictive of poor autumn and winter field conditions, are associated with male-biased sex ratios, achieved in part through selective perinatal maternal infanticide of female offspring. Higher peak litter sizes were associated with increased cannibalism rates, decreased final litter counts, and increased body mass of pups surviving to weaning. To our knowledge this is the first report of sex ratio adjustment by offspring cannibalism.

  12. Reserve Growth in Oil Fields of West Siberian Basin, Russia

    USGS Publications Warehouse

    Verma, Mahendra K.; Ulmishek, Gregory F.

    2006-01-01

    Although reserve (or field) growth has proven to be an important factor contributing to new reserves in mature petroleum basins, it is still a poorly understood phenomenon. Limited studies show that the magnitude of reserve growth is controlled by several major factors, including (1) the reserve booking and reporting requirements in each country, (2) improvements in reservoir characterization and simulation, (3) application of enhanced oil recovery techniques, and (4) the discovery of new and extensions of known pools in discovered fields. Various combinations of these factors can affect the estimates of proven reserves in particular fields and may dictate repeated estimations of reserves during a field's life. This study explores the reserve growth in the 42 largest oil fields in the West Siberian Basin, which contain about 55 percent of the basin's total oil reserves. The West Siberian Basin occupies a vast swampy plain between the Ural Mountains and the Yenisey River, and extends offshore into the Kara Sea; it is the richest petroleum province in Russia. About 600 oil and gas fields with original reserves of 144 billion barrels of oil (BBO) and more than 1,200 trillion cubic feet of gas (TCFG) have been discovered. The principal oil reserves and most of the oil fields are in the southern half of the basin, whereas the northern half contains mainly gas reserves. Sedimentary strata in the basin consist of Upper Triassic through Tertiary clastic rocks. Most oil is produced from Neocomian (Lower Cretaceous) marine to deltaic sandstone reservoirs, although substantial oil reserves are also in the marine Upper Jurassic and continental to paralic Lower to Middle Jurassic sequences. The majority of oil fields are in structural traps, which are gentle, platform-type anticlines with closures ranging from several tens of meters to as much as 150 meters (490 feet). Fields producing from stratigraphic traps are generally smaller except for the giant Talin field which

  13. Evaluation of European tick-borne encephalitis virus vaccine against recent Siberian and far-eastern subtype strains.

    PubMed

    Hayasaka, D; Goto, A; Yoshii, K; Mizutani, T; Kariwa, H; Takashima, I

    2001-09-14

    To evaluate the efficacy of the European TBE vaccine in east-Siberian and far-eastern regions of Russia, we examined the immune responses of the vaccine against recent TBE virus Siberian (Irkutsk) and far-eastern (Khabarovsk and Vladivostok) isolates. The sera of vaccinated humans showed efficient neutralizing antibody titers (> or =20) against Siberian and far-eastern strains. To evaluate the efficacy of the vaccine in vivo, mice were vaccinated and challenged with lethal doses of the viruses. All vaccinated mice survived each virus challenge. These results suggest that the European vaccine can prevent the TBE virus infection in east-Siberian and far-eastern regions of Russia.

  14. Hypolipidemic effects and safety of Lactobacillus reuteri 263 in a hamster model of hyperlipidemia.

    PubMed

    Huang, Wen-Ching; Chen, Yi-Ming; Kan, Nai-Wen; Ho, Chun-Sheng; Wei, Li; Chan, Ching-Hung; Huang, Hui-Yu; Huang, Chi-Chang

    2015-05-15

    We aimed to verify the beneficial effects of probiotic strain Lactobacillus reuteri 263 (Lr263) on hypolipidemic action in hamsters with hyperlipidemia induced by a 0.2% cholesterol and 10% lard diet (i.e., high-cholesterol diet (HCD)). Male Golden Syrian hamsters were randomly divided into two groups: normal (n = 8), standard diet (control), and experimental (n = 32), a HCD. After a two-week induction followed by a six-week supplementation with Lr263, the 32 hyperlipidemic hamsters were divided into four groups (n = 8 per group) to receive vehicle or Lr263 by oral gavage at 2.1, 4.2, or 10.5 × 10(9) cells/kg/day for 6 weeks, designated the HCD, 1X, 2X and 5X groups, respectively. The efficacy and safety of Lr263 supplementation were evaluated by lipid profiles of serum, liver and feces and by clinical biochemistry and histopathology. HCD significantly increased serum levels of total cholesterol (TC), triacylglycerol (TG) cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), LDL-C/HDL-C ratio, hepatic and fetal TC and TG levels, and degree of fatty liver as compared with controls. Lr263 supplementation dose dependently increased serum HDL-C level and decreased serum TC, TG, LDL-C levels, LDL-C/HDL-C ratio, hepatic TC and TG levels, and fecal TG level. In addition, Lr263 supplementation had few subchronic toxic effects. Lr263 could be a potential agent with a hypolipidemic pharmacological effect.

  15. Hypolipidemic Effect of Tomato Juice in Hamsters in High Cholesterol Diet-Induced Hyperlipidemia.

    PubMed

    Lee, Li-Chen; Wei, Li; Huang, Wen-Ching; Hsu, Yi-Ju; Chen, Yi-Ming; Huang, Chi-Chang

    2015-12-17

    Tomato is a globally famous food and contains several phytonutrients including lycopene, β-carotene, anthocyanin, and flavonoids. The increased temperature used to produce tomato juice, ketchup, tomato paste and canned tomato enhances the bioactive composition. We aimed to verify the beneficial effects of processed tomato juice from Kagome Ltd. (KOT) on hypolipidemic action in hamsters with hyperlipidemia induced by a 0.2% cholesterol and 10% lard diet (i.e., high-cholesterol diet (HCD)). Male Golden Syrian hamsters were randomly divided into two groups for treatment: normal (n = 8), standard diet (control); and experimental (n = 32), HCD. The 32 hamsters were further divided into four groups (n = 8 per group) to receive vehicle or KOT by oral gavage at 2787, 5573, or 13,934 mg/kg/day for six weeks, designated the HCD-1X, -2X and -5X groups, respectively. The efficacy and safety of KOT supplementation was evaluated by lipid profiles of serum, liver and feces and by clinical biochemistry and histopathology. HCD significantly increased serum levels of total cholesterol (TC), triacylglycerol (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), LDL-C/HDL-C ratio, hepatic and fetal TC and TG levels, and degree of fatty liver as compared with controls. KOT supplementation dose-dependently decreased serum TC, TG, LDL-C levels, LDL-C/HDL-C ratio, hepatic TC and TG levels, and fecal TG level. Our study provides experiment-based evidence to support that KOT may be useful in treating or preventing the onset of hyperlipidemia.

  16. Hypolipidemic Effects and Safety of Lactobacillus Reuteri 263 in a Hamster Model of Hyperlipidemia

    PubMed Central

    Huang, Wen-Ching; Chen, Yi-Ming; Kan, Nai-Wen; Ho, Chun-Sheng; Wei, Li; Chan, Ching-Hung; Huang, Hui-Yu; Huang, Chi-Chang

    2015-01-01

    We aimed to verify the beneficial effects of probiotic strain Lactobacillus reuteri 263 (Lr263) on hypolipidemic action in hamsters with hyperlipidemia induced by a 0.2% cholesterol and 10% lard diet (i.e., high-cholesterol diet (HCD)). Male Golden Syrian hamsters were randomly divided into two groups: normal (n = 8), standard diet (control), and experimental (n = 32), a HCD. After a two-week induction followed by a six-week supplementation with Lr263, the 32 hyperlipidemic hamsters were divided into four groups (n = 8 per group) to receive vehicle or Lr263 by oral gavage at 2.1, 4.2, or 10.5 × 109 cells/kg/day for 6 weeks, designated the HCD, 1X, 2X and 5X groups, respectively. The efficacy and safety of Lr263 supplementation were evaluated by lipid profiles of serum, liver and feces and by clinical biochemistry and histopathology. HCD significantly increased serum levels of total cholesterol (TC), triacylglycerol (TG) cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), LDL-C/HDL-C ratio, hepatic and fetal TC and TG levels, and degree of fatty liver as compared with controls. Lr263 supplementation dose dependently increased serum HDL-C level and decreased serum TC, TG, LDL-C levels, LDL-C/HDL-C ratio, hepatic TC and TG levels, and fecal TG level. In addition, Lr263 supplementation had few subchronic toxic effects. Lr263 could be a potential agent with a hypolipidemic pharmacological effect. PMID:25988768

  17. Hypolipidemic Effect of Tomato Juice in Hamsters in High Cholesterol Diet-Induced Hyperlipidemia

    PubMed Central

    Lee, Li-Chen; Wei, Li; Huang, Wen-Ching; Hsu, Yi-Ju; Chen, Yi-Ming; Huang, Chi-Chang

    2015-01-01

    Tomato is a globally famous food and contains several phytonutrients including lycopene, β-carotene, anthocyanin, and flavonoids. The increased temperature used to produce tomato juice, ketchup, tomato paste and canned tomato enhances the bioactive composition. We aimed to verify the beneficial effects of processed tomato juice from Kagome Ltd. (KOT) on hypolipidemic action in hamsters with hyperlipidemia induced by a 0.2% cholesterol and 10% lard diet (i.e., high-cholesterol diet (HCD)). Male Golden Syrian hamsters were randomly divided into two groups for treatment: normal (n = 8), standard diet (control); and experimental (n = 32), HCD. The 32 hamsters were further divided into four groups (n = 8 per group) to receive vehicle or KOT by oral gavage at 2787, 5573, or 13,934 mg/kg/day for six weeks, designated the HCD-1X, -2X and -5X groups, respectively. The efficacy and safety of KOT supplementation was evaluated by lipid profiles of serum, liver and feces and by clinical biochemistry and histopathology. HCD significantly increased serum levels of total cholesterol (TC), triacylglycerol (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), LDL-C/HDL-C ratio, hepatic and fetal TC and TG levels, and degree of fatty liver as compared with controls. KOT supplementation dose-dependently decreased serum TC, TG, LDL-C levels, LDL-C/HDL-C ratio, hepatic TC and TG levels, and fecal TG level. Our study provides experiment-based evidence to support that KOT may be useful in treating or preventing the onset of hyperlipidemia. PMID:26694461

  18. Effect of selenium supplementation on histopathology of vitamin E deficiency in the syrian golden hamster

    SciTech Connect

    Hinton, D.E.; Banks, M.A.; Martin, W.G.

    1986-03-01

    Male hamsters (N-40) were placed on a semi-purified torula yeast diet (< 0.05 ppm Se) containing 0.1 ppm added Se (as Na/sub 2/SeO/sub 3/) at age 6-8 weeks, then assigned to either vitamin E deficient (< 1 I.U./100 g, DS) or sufficient (1.5 I.U./100 g CS) diets and pair-fed. Body weights were recorded at 3 week intervals. At 65, 92, 120 and 180 days on diet (dod) two pairs of hamsters were sacrificed by injection of 10 cc/kg Brevital sodium. Blood samples were obtained from the inferior vena cava. Organs were removed, weighted, fixed, routinely processed and stained with hematoxylin and eosin. DS began to lose weight relative to CS at 75 dod. At 92 dod DS plasma ..cap alpha..-tocopherol decreased (DS = 4.3 +/- 1.2, CS = 36.7 +/- 4.4 ..mu..g/ml, p < 0.01), while at 180 dod, RBC hemolysis did not significantly differ (DS = 19.2 +/- 11.3, CS = 3.9 +/-2.7%, p < 0.10). A previous study indicated that dietary vitamin E plus Se deficiencies resulted in depressed growth (70 dod), increased RBC hemolysis (90 dod), muscle degeneration (120 dod), hepatocellular hypertrophy (180 dod) and acinar cell atrophy of the pancreas (170 dod). At 180 dod, Se-supplemented vitamin E deficient hamsters did not display muscle degeneration, hypertrophy of the liver or atrophy of the pancreas, but did have testicular atrophy. None of the DS animals died.

  19. Effects of policosanols and phytosterols on lipid levels and cholesterol biosynthesis in hamsters.

    PubMed

    Wang, Y W; Jones, P J H; Pischel, I; Fairow, C

    2003-02-01

    The current study was carried out to examine the effects of policosanols and phytosterols, alone and in combination, on lipid profiles, cholesterol biosynthesis, and tissue histopathological changes in hamsters. Fifty male Golden Syrian hamsters, weighing 100 to 120 g, were fed a regular rodent chow for 2 wk before being randomly assigned into 5 groups of 10 animals each fed semisynthetic diets for 4 wk. Group 1 was given a control diet that contained 0.25% cholesterol and 5% fat with a PUFA to saturated FA ratio of 0.4. Groups 2 to 5 were fed the control diet and given Octa-6 [a policosanol mixture from sugar cane wax, 25 mg/kg body weight (BW)], Ricewax (a policosanol mixture from rice wax with 50% being converted to the corresponding acids, 50 mg/kg BW), phytosterols (Cholestatin; 1,000 mg/kg BW), and Ricewax (50 mg/kg BW) plus phytosterols (1,000 mg/kg BW), respectively. The results showed that there was no difference between Octa-6 and Ricewax treatments in any of the lipid parameters measured, and both had similar levels of triglyceride (TG), total cholesterol (T-C), and HDL cholesterol (HDL-C) as the control. Octa-6 but not Ricewax increased (P = 0.03) non-HDL-C as compared with the control. Phytosterols reduced T-C (P < 0.0003) and HDL-C (P < 0.004) without a significant effect on TG and non-HDL-C as compared to the control. Ricewax plus phytosterols had effects similar to those with phytosterols alone. Free cholesterol synthetic rates were not different among the treatments. Policosanols or phytosterols did not show any toxic effects in liver, heart, brain, or kidney. Results suggest that, although phytosterols reduce T-C and HDL-C levels, policosanols have no significant favorable effect in changing lipid levels in hamsters.

  20. Injected phytosterols/stanols suppress plasma cholesterol levels in hamsters.

    PubMed

    Vanstone, C A.; Raeini-Sarjaz, M; Jones, P J.H.

    2001-10-01

    Although plant sterols are known to suppress intestinal cholesterol absorption, whether plasma and hepatic lipid levels are influenced through non-gut related internal mechanisms has not been established. To examine this question 50 male hamsters were divided into 5 groups and fed semi-purified diets containing 20% energy as fat and 0.25% (w/w) cholesterol ad libitum for 60 days. The control group (i) received diet alone, while four additional groups consumed the diet plus one of four equivalent phytosterol mixtures (5 mg/kg/day) given either as (ii) tall oil phytosterols/stanols mixed with diet (oralSA), (iii) tall oil phytosterols/stanols subcutaneously injected (subSA), (iv) soybean oil phytosterols alone mixed with diet (oralSE), or (v) soybean oil subcutaneous injected phytosterols alone (subSE). The control group and both orally supplemented groups also received placebo subcutaneous sham injections. Neither food consumption, body weight, nor liver weight differed across treatment groups. Subcutaneous administration of SA and SE decreased plasma total cholesterol levels by 21% and 23% (p < 0.0001) and non-apolipoprotein-A cholesterol concentrations by 22% and 15% (p < 0.0002), respectively, compared to control. HDL cholesterol and TG concentrations remained unchanged across all groups, except for a decline of 25% (p < 0.0001) in HDL concentration in the subSE group versus control. Plasma campesterol levels were lower (p < 0.05) in the subSA group relative to all other groups. Plasma campesterol:cholesterol and campesterol:sitosterol ratios were, however, higher (p < 0.0001) for both the oral and subSE groups. Hepatic cholesterol levels were higher (p < 0.0001) in the oral and subSE phytosterol groups by 30% and 31%, respectively, relative to control. We conclude that low doses of subcutaneously administered plant sterols reduce circulating cholesterol levels through mechanisms other than inhibiting intestinal cholesterol absorption.

  1. Effect of vitamin E deficiency on pancreatic tumors induced by N-nitrosobis(2-oxopropyl)amine (BOP) in the syrian golden hamster

    SciTech Connect

    Banks, M.A.; Martin, W.G.; Hinton, D.E.

    1986-03-05

    Male hamsters (N=100) were injected i.p. with 40 mg/kg BOP at 8 wk, then assigned to a vitamin E deficient (< 1 I.U./100g, D) or sufficient (150 I.U./100g, C) semi-purified diet and pair-fed. To prevent interaction with Se, diets were torula yeast based (< 0.05 ppm Se). After 120 d on diet (dod), the hamsters were fed the C diet for the remainder of the trial. A previous study indicated that this dietary regimine prevented mortality due to vitamin E depletion to at least 420 dod. At 90 dod two pairs of hamsters were sacrificed to confirm E deficiency. RBC hemolysis increased in D (D=87.1 +/- 6.5%, C=43.9 +/- 4.4%, p < 0.05) and plasma ..cap alpha..-tocopherol decreased (D=22.5 +/- 3.8, C=43.9 +/- 4.7 ..mu..g/ml, p < 0.05). D hamsters lost weight relative to C from 60-185 dod only. Moribund hamsters were sacrificed. Gross examination revealed nodules in liver and pancreas of animals dying at greater than or equal to 33 wk post-injection. At 52 wk, 50% of D had died and the remaining D hamsters were sacrificed. Mortality (50%) was delayed by 8 wk in C. From 33-52 wk, D:C mortality was 1.6. This suggests that dietary vitamin E deficiency decreased the latency period for onset of tumors. Histological examination showed pancreatic tumors and associated lesions, including cystic foci, cystadenomas and adenocarcinomas.

  2. Proteomic Analysis of Chinese Hamster Ovary Cells

    PubMed Central

    Baycin-Hizal, Deniz; Tabb, David L.; Chaerkady, Raghothama; Chen, Lily; Lewis, Nathan E.; Nagarajan, Harish; Sarkaria, Vishaldeep; Kumar, Amit; Wolozny, Daniel; Colao, Joe; Jacobson, Elena; Tian, Yuan; O'Meally, Robert N.; Krag, Sharon S.; Cole, Robert N.; Palsson, Bernhard O.; Zhang, Hui; Betenbaugh, Michael

    2013-01-01

    In order to complement the recent genomic sequencing of Chinese hamster ovary (CHO) cells, proteomic analysis was performed on CHO including the cellular proteome, secretome, and glycoproteome using tandem mass spectrometry (MS/MS) of multiple fractions obtained from gel electrophoresis, multi-dimensional liquid chromatography, and solid phase extraction of glycopeptides (SPEG). From the 120 different mass spectrometry analyses generating 682,097 MS/MS spectra, 93,548 unique peptide sequences were identified with at most a 0.02 false discovery rate (FDR). A total of 6164 grouped proteins were identified from both glycoproteome and proteome analysis, representing an 8-fold increase in the number of proteins currently identified in the CHO proteome. Furthermore, this is the first proteomic study done using CHO genome exclusively which provides for more accurate identification of proteins. From this analysis, the CHO codon frequency was determined and found to be distinct from humans, which will facilitate expression of human proteins in CHO cells. Analysis of the combined proteomic and mRNA data sets indicated the enrichment of a number of pathways including protein processing and apoptosis but depletion of proteins involved in steroid hormone and glycosphingolipid metabolism. 504 of the detected proteins included N-acetylation modifications and 1292 different proteins were observed to be N-glycosylated. This first large-scale proteomic analysis will enhance the knowledge base about CHO capabilities for recombinant expression and provide information useful in cell engineering efforts aimed at modifying CHO cellular functions. PMID:22971049

  3. Treatment of disseminated histoplasmosis in hamsters.

    PubMed

    Finquelievich, J L; Negroni, R; Iovannitti, C; Bava, A J

    1989-02-01

    A comparative study between itraconazole, ketoconazole and amphotericin B in the treatment of experimental histoplasmosis in hamsters was carried out. Seventy five animals were inoculated intracardiacally with the yeast-phase of Histoplasma capsulatum. They were divided in 5 groups: 1) treated with itraconazole by gavage (g) at a daily dose of 16 mg/kg; 2) treated with ketoconazole by (g) at a daily dose of 80 mg/kg; 3) treated with amphotericin B intraperitoneally (i.p.) at 6 mg/kg every other day; 4) control animals receiving distilled water i.p. and 5) control animals receiving P.E.G. 200 by (g). All the treatments were started one week after the challenge inoculation and they were given for 21 days. The results were evaluated by autopsy of all the animals one week after the end of the treatments. The following determinations were taken into account: microscopic examinations of spleen, liver and lungs and cultures of the spleen with determination of colony forming units/g. All the antifungal drugs used in this study were able to cause negative microscopic examinations of the liver, spleen and lungs; but only amphotericin B produced culture negative results. Itraconazole and ketoconazole presented 66% and 86% of positive cultures respectively, nevertheless the C.F.U. were lower than those obtained in control groups. In these experimental conditions amphotericin B seems to be more active than the azolic compounds and itraconazole is slightly superior to ketoconazole at a lower dose.

  4. Humoral and cellular response to infection with Echinostoma revolutum in the golden hamster, Mesocricetus auratus.

    PubMed

    Mabus, J; Huffman, J E; Fried, B

    1988-06-01

    Laboratory hamsters (Mesocricetus auratus) were infected with Echinostoma revolutum (Trematoda). Immunoelectrophoretic studies of hamster serum showed no demonstrable antibody response to E. revolutum. Histopathologic examination of intestinal tissue of infected hamsters showed erosion of intestinal villi and lymphocytic infiltration as the primary host response. Spleens from infected hamsters were hyperplastic during the first 3 weeks of infection and atrophic from 4 to 8 weeks postinfection. Hamsters were unable to acquire a resistance to E. revolutum infection. Lack of resistance was demonstrated in hamsters where the parasite infection was no longer detected based on the absence of eggs in the faeces; these hamsters were then reinfected. Hamsters treated with the anthelmintic oxyclozanide were also reinfected with E. revolutum.

  5. Clinical, hematological and biochemical alterations in hamster (Mesocricetus auratus) experimentally infected with Leishmania infantum through different routes of inoculation.

    PubMed

    Moreira, Nádia das Dores; Vitoriano-Souza, Juliana; Roatt, Bruno Mendes; Vieira, Paula Melo de Abreu; Coura-Vital, Wendel; Cardoso, Jamille Mirelle de Oliveira; Rezende, Mariana Trevisan; Ker, Henrique Gama; Giunchetti, Rodolfo Cordeiro; Carneiro, Claudia Martins; Reis, Alexandre Barbosa

    2016-03-31

    Leishmaniasis remains among the most important parasitic diseases in the developing world and visceral leishmaniasis (VL) is the most fatal. The hamster Mesocricetus auratus is a susceptible model for the characterization of the disease, since infection of hamsters with L. infantum reproduces the clinical and pathological features of human VL. In this context, it provides a unique opportunity to study VL in its active form. The main goal of this study was to evaluate the clinical, biochemical, and hematological changes in male hamsters infected through different routes and strains of L. infantum. In the current study, hamsters (Mesocricetus auratus) were infected with the L. infantum strains (WHO/MHOM/BR/74/PP75 and MCAN/BR/2008/OP46) by intradermal, intraperitoneal and intracardiac routes. The animals were monitored for a nine month follow-up period. The hamsters showed clinical signs similar to those observed in classical canine and human symptomatic VL, including splenomegaly, severe weight loss, anemia, and leucopenia. Therefore the OP46 strain was more infective, clinical signs were more frequent and more exacerbated in IC group with 80 to 100 % of the animals showing splenomegaly, in the last month infection. Additionally, desquamation, hair loss and external mucocutaneous lesions and ulcers localized in the snout, accompanied by swelling of the paws in all animals, were observed. Consequently, the animals presented severe weight loss/cachexia, hunched posture, an inability to eat or drink, and non-responsiveness to external stimuli. Furthermore, regardless of strain, route of inoculum and time assessed, the animals showed renal and hepatic alterations, with increased serum levels of urea and creatinine as well as elevated serum levels of aspartate aminotransferase and alanine aminotransferase. These results strongly suggest that the inoculation through the intracardiac route resulted in a higher severity among infections, especially in the sixth and ninth

  6. The hamster flank organ model: Is it relevant to man

    SciTech Connect

    Franz, T.J.; Lehman, P.A.; Pochi, P.; Odland, G.F.; Olerud, J. )

    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 study 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.

  7. 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

  8. 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

  9. Circadian Regulation of Cortisol Release in Behaviorally Split Golden Hamsters

    PubMed Central

    Lilley, Travis R.; Wotus, Cheryl; Taylor, Daniel; Lee, Jennifer M.

    2012-01-01

    The master circadian clock located within the hypothalamic suprachiasmatic nucleus (SCN) is necessary for the circadian rhythm of glucocorticoid (GC) release. The pathways by which the SCN sustains rhythmic GC release remain unclear. We studied the circadian regulation of cortisol release in the behaviorally split golden hamster, in which the single bout of circadian locomotor activity splits into two bouts approximately12 h apart after exposing the animals to constant light conditions. We show that unsplit control hamsters present a single peak of cortisol release that is concomitant with a single peak of ACTH release. In contrast, split hamsters show two peaks of cortisol release that are approximately12 h appart and are appropriately phased to each locomotor activity bout but surprisingly do not rely on rhythmic release of ACTH. Our results are consistent with a model in which the circadian pacemaker within the SCN regulates the circadian release of GC via input to the hypothalamo-pituitary-adrenal axis and via a second regulatory pathway, which likely involves sympathetic innervation of the adrenal and can operate even in the absence of ACTH circadian rhythmic release. Furthermore, we show that although the overall 24-h cortisol output in split hamsters is lower than in unsplit controls, split hamsters release constant low levels of ACTH. This result suggests that the timing, rather than the absolute amount, of cortisol release is more critical for the induction of negative feedback effects that regulate the hypothalamo-pituitary-adrenal axis. PMID:22128030

  10. Circadian regulation of cortisol release in behaviorally split golden hamsters.

    PubMed

    Lilley, Travis R; Wotus, Cheryl; Taylor, Daniel; Lee, Jennifer M; de la Iglesia, Horacio O

    2012-02-01

    The master circadian clock located within the hypothalamic suprachiasmatic nucleus (SCN) is necessary for the circadian rhythm of glucocorticoid (GC) release. The pathways by which the SCN sustains rhythmic GC release remain unclear. We studied the circadian regulation of cortisol release in the behaviorally split golden hamster, in which the single bout of circadian locomotor activity splits into two bouts approximately 12 h apart after exposing the animals to constant light conditions. We show that unsplit control hamsters present a single peak of cortisol release that is concomitant with a single peak of ACTH release. In contrast, split hamsters show two peaks of cortisol release that are approximately 12 h appart and are appropriately phased to each locomotor activity bout but surprisingly do not rely on rhythmic release of ACTH. Our results are consistent with a model in which the circadian pacemaker within the SCN regulates the circadian release of GC via input to the hypothalamo-pituitary-adrenal axis and via a second regulatory pathway, which likely involves sympathetic innervation of the adrenal and can operate even in the absence of ACTH circadian rhythmic release. Furthermore, we show that although the overall 24-h cortisol output in split hamsters is lower than in unsplit controls, split hamsters release constant low levels of ACTH. This result suggests that the timing, rather than the absolute amount, of cortisol release is more critical for the induction of negative feedback effects that regulate the hypothalamo-pituitary-adrenal axis.

  11. 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

  12. Acquired immunity to Mycoplasma pneumoniae. Pneumonia in hamsters.

    PubMed

    Hayatsu, E

    1978-01-01