PubMed Health⌕ Search

Biomedical subjects

F Silverstein

Publications and source records attributed to F Silverstein.

At least 19 recordsLinked to original sources
PubMed1991

Nonsteroidal anti-inflammatory drugs and peptic ulcer disease. An overview.

Evidence is accumulating that use of nonsteroidal anti-inflammatory drugs (NSAIDs) is linked to ulceration of the stomach and duodenum and can cause significant, life-threatening ulcer complications. The mechanism of action seems to be both topical damage to the mucosal barrier and the systemic effect of a reduction in levels of mucosal prostaglandins. Patients especially at risk are the elderly, those with concomitant debilitating disease, those with a history of ulcers, and those taking corticosteroids. Histamine2 blockers are reported to significantly reduce the incidence of NSAID-induced duodenal ulcer, and misoprostol (Cytotec) has been shown to significantly reduce the incidence of NSAID-induced gastric ulcer. Prophylaxis with these agents should be considered for high-risk patients who need NSAID therapy to maintain a reasonable life-style.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1989

Lidocaine pharmacokinetics during water immersion in normal humans.

Water immersion produces a marked diuresis, natriuresis, and kaliuresis in association with suppression of the renin-aldosterone system. These effects are mediated primarily by an increase in central blood volume. Consequently, this redistribution and the resultant marked increase in cardiac output is associated with alterations in the circulating levels of several volume regulatory hormones, including plasma renin activity and plasma aldosterone. Although the changes in these blood hormonal levels probably reflect perturbation of hormonal release, it is conceivable that the above-mentioned central hemodynamic modifications result in an altered splanchnic blood flow, thereby modulating hormonal clearances. We assessed the effects of immersion on hepatic blood flow by determining the pharmacokinetics of single doses of lidocaine administered intravenously. Seven normal male subjects were studied during a time-control period and during water immersion to the neck. The clearance of lidocaine was unaltered by immersion, suggesting that the presumed marked central hypervolemia and increased cardiac output was not associated with changes in splanchnic blood flow.

Adult↗
PubMed1989

P & T committee review of misoprostol: prevention of NSAID side effects is key--roundtable discussion.

Misoprostol, a prostaglandin of the E series, was recently introduced for the prevention of NSAID-induced gastric ulcers. Misoprostol was classified as "1A" (denoting a new chemical entity that is a significant therapeutic advance) for purposes of review priority by the Food and Drug Administration in 1988. A dosage of 200 micrograms qid is recommended for prophylaxis, for the duration of NSAID therapy. Misoprostol is generally well-tolerated, with some patients reporting diarrhea. Misoprostol should not be given to pregnant women because of its uterotonic effects. (Please see full prescribing information for a discussion of the safety profile of misoprostol.) Because of the magnitude of the problem of NSAID-induced gastric ulceration and the expense of treatments and hospitalizations, the use of misoprostol in preventing these ulcers should be clinically beneficial, and may contribute to significant cost savings in the hospital and other managed-care settings.

Alprostadil↗
PubMed1986

Ultrasound and the intestinal wall: experimental methods.

High-frequency, high-resolution ultrasound provides a new approach to imaging structures in the wall of the gastrointestinal tract. Questions about internal ultrasound include: is the ultrasound image specific for disease states, in which diseases will this technology add new and useful information not available from existing diagnostic studies, and what are the necessary characteristics for a system to accomplish these diagnoses? Answering these questions requires that precise correlations be made between the ultrasound image and pathology. We have developed a method to image a resected gastrointestinal tissue with ultrasound and to remove and examine the corresponding piece of tissue histologically. Changes in wall thickness, obliteration of layers, and changes in the characteristics of the tissue can be studied. We have shown that ultrasound can resolve the layers of the gut wall. This system should enable us to answer questions about which intestinal wall diseases are suitable for internal ultrasound imaging and characterize the engineering features of an optimal ultrasound system for clinical application.

Digestive System↗
PubMed1985

Effect of clonidine on platelet alpha 2-adrenoreceptors and plasma norepinephrine of children with Tourette syndrome.

Clonidine, an alpha 2-adrenoreceptor agonist, is useful for treating some patients with Tourette syndrome, and it has been suggested that their noradrenergic receptors are 'subsensitive'. The authors measured plasma norepinephrine and specific binding of 3H-clonidine and 3H-yohimbine, an alpha 2-adrenoreceptor antagonist, to receptors on platelet membranes from children with Tourette syndrome. Before clonidine treatment, plasma norepinephrine, the maximum number of binding sites and the dissociation constants for both ligands were the same as for the controls. After two weeks of treatment there was little clinical improvement, but the number of binding sites for 3H-yohimbine decreased and plasma norepinephrine also decreased in four of the five patients. Over the next six months all five patients continued to improve clinically, but both indices of noradrenergic activity returned towards baseline values. The data suggest that clonidine's action may be independent of its prominent effects on alpha 2-adrenergic receptors and norepinephrine release.

Blood Platelets↗
PubMed1984

Pathogenesis of hypoxic-ischemic brain injury in a perinatal rodent model.

Exposure of immature rats to 8% oxygen after unilateral carotid artery ligation (UCL) causes metabolic, neurochemical and histopathological changes in the ipsilateral forebrain that resemble those in human perinatal hypoxic-ischemic encephalopathy. Regional cerebral perfusion in this model was examined by visual analysis of India ink trapped in cerebral vessels and measurement of [14C]iodoantipyrine [( 14C]IAP) and [3H]flunitrazepam extraction into the brain. UCL alone reduced [14C]IAP accumulation in the ipsilateral hemisphere by 20% and hypoxia superimposed on UCL progressively reduced ipsilateral hemisphere perfusion by 71% at 2 h. Hypoxia probably injures neurons in this model by causing a critical reduction in cerebral perfusion, an effect which also appears to be important in the human disorder.

Animals↗
PubMed1984

Effects of hypoxia-ischemia on monoamine metabolism in the immature brain.

We measured acute changes in monoamine metabolites in corpus striatum of immature rat pups exposed to hypoxia-ischemia, hypoxia alone, or total global ischemia. Carotid ligations and two hours of 8% oxygen environment in 7-day-old pups led to asymmetrical turning behavior, a 70% decrease in endogenous striatal dopamine levels, and a 125% increase in homovanillic acid (HVA) concentrations on the side of ligation. In contrast, hypoxia alone and total global ischemia alone were not associated with HVA level elevation. Elevation of HVA level with hypoxia-ischemia showed a threshold effect between 1 and 1.5 hours, and this time course paralleled that for production of gross morphological changes in rats raised to maturity. The data suggest that dopamine release from striatal nerve terminals is associated with events causing brain injury during perinatal hypoxia-ischemia. Tissue HVA in the animal model appears to be a quantitative marker for the effects of the insult on a population of nerve terminals.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1984

Cerebrospinal fluid monoamine metabolites in patients with infantile spasms.

We measured CSF levels of homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) by high-performance liquid chromatography in seven children with infantile spasms and in a group of age- and sex-matched controls. The mean concentration of the serotonin metabolite 5-HIAA was 40% (p less than 0.01) lower in the infantile spasms group as compared with controls; HVA levels were similar in both groups. The data provide additional evidence that serotonin metabolism is abnormal in patients with infantile spasms.

Adolescent↗
PubMed1983

Head-control system for severely paralyzed patient.

A device to provide controlled suspension of the head of the severely paralyzed patient while seated is described. Mounted on the wheelchair, it permits functional range-of-motion of the head on the neck. It does not contact the neck or chin.

Equipment Design↗