Altered representation of naive and memory CD8 T cell subsets in HIV-infected children.

CD8 T cells are divided into naive and memory subsets according to both function and phenotype. In HIV-negative children, the naive subset is present at high frequencies, whereas memory cells are virtually absent. Previous studies have shown that the overall number of CD8 T cells does not decrease in HIV-infected children.

The time-dependent stimulus effects of R(-)-2,5-dimethoxy-4-methamphetamine (DOM): implications for drug-induced stimulus control as a method for the study of hallucinogenic agents.

The pharmacodynamic characteristics of the stimulus effects of the hallucinogens d-LSD and (-)DOM were investigated in the rat. The stimulus control induced by (-)DOM (0.56 mg/kg) was significantly less stable at the 15-min pretreatment time than at the 75-min pretreatment time.

The role of the 5-HT2A and 5-HT2C receptors in the stimulus effects of m-chlorophenylpiperazine.

m-Chlorophenylpiperazine (mCPP), a major metabolite of the atypical antidepressant trazadone, has been observed to produce marked physiological and behavioral effects in both humans and animals. These effects have been attributed to the interaction of mCPP with serotonergic receptors. The present study was designed to characterize those interactions of mCPP with central serotonergic receptors which mediate mCPP-induced stimulus control.

Elevated blood lead levels among construction workers in the Massachusetts Occupational Lead Registry.

Although the construction industry until recently was exempt from the Occupational Health and Safety Administration General Industry Lead Standard, including its medical monitoring provisions, periodic blood lead tests have been required for residential "deleaders" and structural painters in Massachusetts. Sixty-three percent of the 381 registrants in the Massachusetts Occupational Lead Registry with blood lead levels of 1.93 mumol/L or higher are construction workers.

Chronic ethanol exposure inhibits ATP-stimulated but not KCl-stimulated dopamine release in PC 12 cells.

The functional significance of the ethanol-induced alterations in intracellular concentration of free calcium ([Ca++]i) was determined in PC 12 cells by measuring agonist-stimulated dopamine (DA) release after ethanol exposure. ATP and KCl produced a concentration-dependent release of DA, which was linearly related to the net increase in [Ca++]i, but different relationships were observed with ATP and KCl. Acute addition of 150 mM ethanol inhibited KCl-stimulated release of DA, but did not alter the response to ATP.

Characterization of the purinergic P2 receptors in PC12 cells. Evidence for a novel subtype.

The properties of the purinergic receptors in the PC12 cells were studied. The rank order of potency to increase [Ca2+]i was: adenosine 5'-O-(1-thiotriphosphate) > ATP > adenosine 5'-O-(3-thiotriphosphate) >>> 3'-O-(4-benzoyl-benzoyl)ATP. ADP, AMP, GTP, UTP, alpha, beta- and beta,gamma-methylene adenosine 5'-triphosphates, 5'-adenylylimido-diphosphate, and adenosine analogues were ineffective.

Nitric oxide reduces depolarization-induced calcium influx in PC12 cells by a cyclic GMP-mediated mechanism.

The present study was undertaken to determine whether nitric oxide (NO) alters voltage-dependent changes in intracellular calcium levels ([Ca2+]i) using PC12 cells as a neuronal model. The addition to PC12 cells of sodium nitroprusside (SNP), which spontaneously releases NO in aqueous solution, significantly inhibited the KCl-stimulated increase in [Ca2+]i. The inhibitory action of SNP was concentration-dependent and was mimicked by hydroxylamine which also generates NO.

Space exploration and toxicology: a new frontier.

Results of the microbial and immunological studies discussed above clearly illustrate an in-flight or post-flight blunting of the cellular immune mechanism in humans and test animals, coincident with a relative increase in pathogenic microorganisms. This situation predicts an increased incidence of in-flight infectious disease events. To prevent this from occurring, most observers agree that a robust program of preflight and in-flight immunological and microbiological monitoring, combined with an effective countermeasures program, are required for optimally successful long-duration spaceflight.

Effects of chronic cocaine administration on the serotonergic system in the rat brain.

Male Sprague-Dawley rats received injections of cocaine (20 mg/kg/dose, IP) every 12 h for 14 days and were sacrificed on the 15th day. The chronic cocaine treatment caused an increase in the levels of serotonin [5-hydroxytryptamine (5-HT)] and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the hippocampus. 5-HIAA levels in the frontal cortex were also increased, but 5-HT levels were unaltered by the chronic cocaine treatment.

Chronic ethanol exposure potentiates muscarinic receptor and alpha 2-adrenoceptor-mediated inhibition of cAMP accumulation in PC 12 cells.

The effects of ethanol on receptor-mediated inhibition of cAMP production were investigated in PC 12 cells. The in vitro addition of ethanol enhanced N-ethylcarboxyadenosine (NECA)-stimulated cAMP production without altering the inhibitory action of carbachol or epinephrine. A 4 day exposure of PC 12 cells to ethanol decreased the stimulation of cAMP production by NECA, but increased the inhibition of NECA-stimulated cAMP production by carbachol and epinephrine.

Differential effects of chronic ethanol exposure on ATP- and bradykinin-induced increases in intracellular calcium levels in PC-12 cells.

The present study investigated the regulation of intracellular calcium levels ([Ca2+]i) by ethanol, ATP, and bradykinin (BK) in PC-12 cells. Acute addition of 150 mM ethanol increased [Ca2+]i but did not alter ATP- and BK-induced increases in [Ca2+]i. After a 4-day exposure to 150 mM ethanol, the maximal response to ATP was decreased 39.

Impact of diagnosis on utilities assigned to states of illness.

This paper addresses some of the fundamental issues surrounding the measurement of quality of life in relation to health care and highlights the need for continuous and careful review. Healthy volunteers were used to study the effect of diagnosis on the utilities placed on three dimensions of health-related quality of life encompassing 17 states of disability, distress, and discomfort including pain. The standard gamble (SG) was used to elicit values for appropriate levels of each dimension for selected diagnostic conditions.

Lipopolysaccharide and peptidoglycan share binding sites on human peripheral blood monocytes.

p73, a binding site for lipopolysaccharide (LPS) on human peripheral blood monocytes was identified using the radiolabeled photoaffinity cross-linker sulfosuccinimidyl 2-(p-azidosalicylamido)ethyl-1,3'-dithiopropionate (SASD). The 125I-labeled conjugate of SASD and LPS (125I-labeled ASD-LPS) was bound to monocytes and UV cross-linked, and the cellular extracts were analyzed with two-dimensional SDS-PAGE and autoradiography. In addition to the major binding site on human monocytes at 73 kDa, isoelectric point 5.

Dual response regulators (NarL and NarP) interact with dual sensors (NarX and NarQ) to control nitrate- and nitrite-regulated gene expression in Escherichia coli K-12.

Two sensor proteins, NarX and NarQ, mediate nitrate regulation of anaerobic respiratory gene expression. Either of these sensors is sufficient to signal the presence of nitrate to the response regulator protein, NarL, a transcriptional activator and repressor. Two observations suggested the existence of a second response regulator that is also involved in nitrate regulation.

Discriminative stimulus properties of m-chlorophenylpiperazine.

Stimulus control was established in a group of 10 rats using a dose of m-chlorophenylpiperazine (MCPP) of 0.8 mg/kg, administered IP, 15 min before training. A two-lever operant task using a fixed-ratio 10 schedule of sweetened milk reinforcement was used.

Regulation of Na+, K(+)-ATPase by chronic ethanol exposure of PC 12 cells.

The effects of chronic ethanol exposure on Na+, K(+)-ATPase were investigated in PC 12 cells. Inclusion of ethanol in the Na+, K(+)-ATPase assay (i.e.

Antagonism of the stimulus effects of yohimbine and 8-hydroxydipropylaminotetralin.

Stimulus control was established in rats using either 8-hydroxy-2-[di-n-propylamino]tetralin (DPAT) (0.2 mg/kg) or yohimbine (3 mg/kg). Tests were then conducted with purported antagonists at 5-hydroxytryptamine1A (5-HT1A) receptors.

Ethanol enhances neurite outgrowth in primary cultures of rat cerebellar macroneurons.

Effects of ethanol on neurite outgrowth and morphometry were investigated in primary cultures of rat cerebella. Cell cultures were prepared from cerebella on embryonic day 17 (E17) for treatment with a series of ethanol concentrations (50, 75, 100, 150 and 200 mM). Ethanol did not reduce neuronal survival or attachment to the substrate at any of the concentrations that were used.

Effects of spaceflight on the musculoskeletal system: NIH and NASA future directions.

Prolonged bed rest, undertaken by volunteers or resulting from injury and disease, can impair bone and muscle function and structure; extended travel in space also induces these effects. Fluid shifts and disrupted fluid balance may also contribute to observed musculoskeletal aberrations in the weightless environment. Some molecular and cellular events involved in the loading and unloading of the musculoskeletal system are under neural and endocrine influence or control, whereas other events are influenced by local growth factors.

Role of extracellular adenosine in ethanol-induced desensitization of cyclic AMP production.

The decrease in receptor-stimulated cyclic AMP production after chronic ethanol exposure was suggested previously to be secondary to an ethanol-induced increase in extracellular adenosine. The present study was undertaken to ascertain whether a similar mechanism was responsible for the ethanol-induced desensitization of cyclic AMP production in PC12 pheochromocytoma cells. The acute addition of ethanol in vitro significantly increased both basal cyclic AMP content and extracellular levels of adenosine.

Ethanol-induced desensitization of adenylate cyclase: role of the adenosine receptor and GTP-binding proteins.

Chronic exposure to ethanol decreases receptor stimulation of cyclic AMP production. In PC 12 cells, chronic treatment with ethanol decreased the maximal stimulation of cyclic AMP accumulation by 2-chloroadenosine without altering the concentration of drug required for half-maximal stimulation. This desensitization was shown to occur after a 7-day exposure to 25 mM ethanol, which is comparable to the legal limit for intoxication in most states.

Yohimbine as a serotonergic agent: evidence from receptor binding and drug discrimination.

Stimulus control was established in rats trained to discriminate either 8-hydroxy-2-(di-n-propylamino)tetralin (DPAT) (0.2 mg/kg) or yohimbine (3 mg/kg) from saline. Tests of generalization were then conducted with a group of drugs thought to act via the 5-hydroxytryptamine1A (5-HT1A) receptor and a group of drugs thought to act as antagonists at alpha 2 adrenoceptors.