HSP70 expression is increased during the day in a diurnal animal, the golden-mantled ground squirrel Spermophilus lateralis.

Heat shock protein 70 (HSP70) gene expression was studied in a seasonal hibernator, the diurnal ground squirrel, Spermophilus lateralis. RNA transcripts of 2.7 and 2.9 kb hybridizing to an HSP70 cDNA were expressed in both brain and peripheral tissues of pre-hibernation euthermic animals; higher levels of expression were observed during the day than during nighttime samples. A decline in the expression of both transcripts occurred in all tissues examined during hibernation that remained low throughout the hibernation season, including the interbout euthermic periods and regardless of time of day. Quantitative comparisons showed pre-hibernation nighttime HSP70 expression to be as low as that observed during hibernation, despite the drastic increase in metabolic state and nearly 30 degrees C difference in body temperature. In contrast to HSP70, some mRNAs, such as beta-actin and HSP60, remained relatively constant, while others, such as glyceraldehyde 3-phosphate dehydrogenase, increased in specific tissues during the hibernation season. These results indicate that the expression of a highly conserved gene involved in protection from cellular stress, HSP70, can vary with an animal's arousal state.

Gene expression in the brain across the hibernation cycle.

The purpose of this study was to characterize changes in gene expression in the brain of a seasonal hibernator, the golden-mantled ground squirrel, Spermophilus lateralis, during the hibernation season. Very little information is available on molecular changes that correlate with hibernation state, and what has been done focused mainly on seasonal changes in peripheral tissues. We produced over 4000 reverse transcription-PCR products from euthermic and hibernating brain and compared them using differential display. Twenty-nine of the most promising were examined by Northern analysis. Although some small differences were observed across hibernation states, none of the 29 had significant changes. However, a more direct approach, investigating expression of putative hibernation-responsive genes by Northern analysis, revealed an increase in expression of transcription factors c-fos, junB, and c-Jun, but not junD, commencing during late torpor and peaking during the arousal phase of individual hibernation bouts. In contrast, prostaglandin D2 synthase declined during late torpor and arousal but returned to a high level on return to euthermia. Other genes that have putative roles in mammalian sleep or specific brain functions, including somatostatin, enkephalin, growth-associated protein 43, glutamate acid decarboxylases 65/67, histidine decarboxylase, and a sleep-related transcript SD464 did not change significantly during individual hibernation bouts. We also observed no decline in total RNA or total mRNA during torpor; such a decline had been previously hypothesized. Therefore, it appears that the dramatic changes in body temperature and other physiological variables that accompany hibernation involve only modest reprogramming of gene expression or steady-state mRNA levels.

Daily variation of CNS gene expression in nocturnal vs. diurnal rodents and in the developing rat brain.

Expression of c-fos has been shown to vary throughout the brain over the course of the 24-h day. The magnitude of these changes appear to be similar in a light:dark (LD) cycle or in constant dark (DD). To further examine whether the diurnal and circadian changes in c-fos and other immediate-early gene (IEG) expression in brain are related to waking behaviors such as locomotor activity, we conducted three experiments using Northern analysis. First, we compared IEG expression in nocturnal vs. diurnally active species. Second, we investigated IEG expression in a hibernating species during its active and inactive phases. Third, we examined the development of IEG expression in the young post-natal rat. As a comparison to results obtained in extra-SCN brain regions, we also examined IEG and vasopressin expression in the SCN itself across the circadian cycle. Animals maintained under a 12:12-h LD cycle were sacrificed in the morning (10:00-11:00 h, ZT2-ZT3) or night (22:00-23:00 h, ZT14-ZT15) or at the corresponding circadian times (CT) when kept in DD. Rats sacrificed in the morning always showed lower c-fos expression than at night in all brain areas examined while the reverse pattern was seen in squirrels under both LD and DD conditions, suggesting a direct correlation between c-fos message and activity. The cerebellum displayed the greatest magnitude change between morning and night (often reaching 10-fold). Among other IEGs examined, the expression of NGFI-A and junB are similar to c-fos, but of lesser magnitude, whereas c-jun appears to be invariant in the rat but is increased during the active phase in squirrels. During the hibernation season, squirrels have lower levels of c-fos consistent with their low levels of activity even during their euthermic interbout periods. c-fos expression in the cerebellum and rest of brain of 1-week-old rats sacrificed at ZT3 and ZT15 showed low levels at both timepoints whereas 2- and 3-week-old animals had higher levels at night as do adults. Among other IEGs, junB and NGFI-A again were similar to c-fos while c-jun and junD were more constant. Our observations support the idea of a diurnal rhythm of IEG expression in the CNS that is related to waking behaviors. Among IEGs, c-fos exhibits the greatest daily variation in expression.

A Model for a Policy on HIV/AIDS and Athletics.

Human immunodeficiency virus (HIV)-infected athletes exist at the collegiate level and are engaging in competitive sports, as was revealed by a 1993 NCAA survey. Unfortunately, there is a void when the issue of policy for the HIV- positive athlete and his or her participation rights at the collegiate level is addressed. Given the controversial nature of opinion on HIV and the resultant acquired immunodeficiency syndrome (AIDS), it is recommended that a policy be in place for an HIV-infected athlete before it is needed. Ithaca College has recently developed such a policy, and it is offered here to other educational institutions as a model. It is emphasized throughout the policy that HIV-positive athletes should not be restricted from athletic participation for the reason of infection alone, that strict confidentiality guidelines should be followed, and that mandatory testing of athletes for HIV is not justified.

Beta-amyloid peptide secretion by a microglial cell line is induced by beta-amyloid-(25-35) and lipopolysaccharide.

beta-Amyloid protein (betaAP) deposition is a neuropathologic hallmark of Alzheimer's disease (AD). Yet, the source of cerebral betaAP in AD is controversial. We examined the production of betaAP by the BV-2 immortalized microglial cell line using a sensitive enzyme immunoassay. Constitutive production of betaAP was detected in conditioned media from unstimulated BV-2 cells. Further, production of betaAP was induced by treatment of cultures by lipopolysaccharide (LPS) or betaAP-(25-35) and was inhibited by the calpain protease inhibitor MDL 28170. Treatment of BV-2 cells with LPS or betaAP-(25-35) did not affect cell-associated beta-amyloid precursor protein levels. These findings suggest that microglia may be an important source of betaAP in AD, and that microglial production of betaAP may be augmented by proinflammatory stimuli or by betaAP itself.

Expression of interleukin-11 and its encoding mRNA by glioblastoma cells.

Interleukin-11 (IL-11) is a pleiotropic cytokine with important effects on hematopoietic and other cells. IL-11 was originally described as a product of stromal cell lines and fibroblasts. Using RT-PCR, Northern blotting, and ELISA we demonstrated that the human U373 and U87 glioblastoma cell lines expressed IL-11 and its encoding mRNA when stimulated with IL-1 beta, phorbol ester, and calcium ionophore. The neuroblastoma cell line SH-SY5Y did not express IL-11 mRNA in response to these agents. Cerebral expression of IL-11 by glial cells is important because IL-11 has been shown to have effects on neuronal electrophysiology, has overlapping functions with the neuroactive cytokine interleukin-6, and is part of the gp130-associated neuropoietic family of cytokines.

C-fos mRNA increases in the ground squirrel suprachiasmatic nucleus during arousal from hibernation.

During hibernation the body temperature of the golden-mantled ground squirrel, Spermophilus lateralis, may drop below 5 degrees C for a few hours to a week or more. Animals cycle between euthermia and deep hibernation many times over the course of the hibernation season. Expression of the transcription factor c-fos increased in the suprachiasmatic nucleus (SCN) of the hypothalamus, the mammalian circadian clock, during deep hibernation and peaked during the arousal from hibernation. The pattern of increase in c-fos messenger RNA seen in the SCN by in situ hybridization was similar to that seen by Northern blot analysis of total hypothalamic RNA. The induction of c-fos may reflect a wake-up signal, increasing transcription of genes required in the euthermic state.

Enhancing athletic injury rehabilitation adherence.

Contemporary sports medicine literature has begun to address more centrally the idea that treatment adherence is a complex issue. Not only must certified athletic trainers (ATCs) possess knowledge about injuries and subsequent rehabilitation protocols, they also must be able to deliver essential services in a manner that predisposes treatment success. Effective treatment of athletic injuries necessitates consideration of various psychosocial factors shown to enhance rehabilitation adherence. Detailed explanations of several important ATC-athlete interaction patterns and motivational strategies are offered.