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Biomedical subjects

S Spector

Publications and source records attributed to S Spector.

At least 91 records · Page 5Linked to original sources
PubMed1980

Pharmacokinetics of d-tubocurarine in man: effect of an osmotic diuretic on urinary excretion.

The pharmacokinetics of d-tubocurarine (dTc) and the urinary excretion of dTc were studied in 18 neurosurgical patients with normal renal function, over a period of 96 hours. The effects of an osmotic diuretic (mannitol) on urinary elimination of dTc were determined. Following a single intravenous dose of d-tubocurarine (dTc, 0.3 mg/kg), serum levels and urinary excretion of the drug were measured. A specific radioimmunoassay was used for the analysis of dTc. Nine of the patients also received mannitol, 1 g/kg, after the injection of dTc for surgical indications. The study showed that only 45 per cent of the injected dose of dTc was excreted in 24 hours. Between 24 and 96 hours, an additional 7 per cent of the drug was excreted in the urine. The administration of mannitol, an osmotic diuretic, did not increase the excretion of dTc. The time-concentration relationship of serum concentration of dTc was analyzed. Using the four-exponential equation (data to 96 hours), the calculated volume of distribution (Vdarea) was 3.4 1/kg. This volume, which is greater than the volume of total body water, suggests that dTc is stored in certain tissues in the body and slowly released over a period of days to weeks.

Half-Life↗
PubMed1980

Isolated brain microvessels: preparation, morphology, histamine and catecholamine contents.

A method for the rapid preparation of parenchymal microvessels from rat, rabbit and bovine brains is described. Light and electron microscopic examination of the isolated microvessels showed the smooth muscle and endothelial cells to be intact and substantially free of neutrophil contamination. The observation of 0.2 to 2.0 micron electron dense granules in the adventitial space associated with some of the isolated arteriolar elements and the identification of histamine in microvessel extracts is suggestive of the presence of mast cells in the microvessel preparations. Age-dependent changes in histamine content and an increased histamine content in microvessels from hypertensive rats were noted. Using a sensitive radioenzymatic assay, the catecholamine (CA) contents of microvessels isolated from cow, rat and rabbit were measured. The total CA contents of all microvessel preparations were small (< 0.35 microgram g-1) with norepinephrine being the predominant CA present. A large ratio of dopamine to norepinephrine was found in microvessels from rat and bovine brain. The possible origins of the CAs present in the isolated microvessels are discussed.

Animals↗
PubMed1980

A screening test for influenza immunity: preimmunization antibody titers to influenza virus antigens in atopic patients.

Antibody titers to three common strains of influenza virus, including the Swine Flu strain, were determined in 152 patients in an allergy and pediatric allergy practice prior to planned immunization with influenza vaccine. Because allergic patients are considered to be more prone to hypersensitivity reactions than individuals who are non-allergic, it was deemed prudent to screen for patients who might have pre-existing protective levels of antibody to the viruses. A considerable number of the 152 patients were found to have titers of 1:20 or 1:40 to one or more of the three influenza strains, including the Swine Flu strain. The largest percentage of positive antibody levels was found to be to the A-Victoria strain which has recently been most prevalent in the northeastern United States. The lowest numbers of patients with protective antibody levels were for the Swine Flu strain. Nevertheless, the highest titers occurred with patient specimens tested against the Swine Flu strain. Approximately one-quarter of the patients showed significant levels of antibody (1:40 or more) to one or more of the virus antigens and thus were not vaccinated, avoiding the possibility of untoward areactions which habe been observed in some individuals who have been given the vaccine.

Adolescent↗
PubMed1980

Mechanism of the antihypertensive action of clonidine on the pressor response to physostigmine.

Physostigmine (P) was used as a model in anesthetized rats for the development of hypertension by a central cholinergic mechanism. P (25-100 micrograms/kg i.v.) produced a dose-related increase in mean arterial pressure which was inhibited 30 to 90% by preinjection of clonidine (100 micrograms/kg i.v.). This dose of clonidine was without effect on the pressor response to ganglionic stimulation produced by 1,1-dimethyl-4-phenylpipera-zinium iodine. To examine further the central inhibitory effect of clonidine on the pressor response to P, regional brain acetylcholine turnover rate was measured in control and clonidine-pretreated rats. Clonidine significantly reduced turnover in hypothalamus (69%), pons-medulla (43%) and midbrain (39%) but not in striatum or hippocampus. These observations are consistent with an inhibitory effect of clonidine on central cholinergic neurons involved in cardiovascular regulation.

Acetylcholine↗
PubMed1980

Nurse training and staffing in the neonatal intensive care unit.

Most nurses are unfamiliar with the highly sophisticated level of technology that must be utilized in the delivery of care in an NICU. This article has presented the measures that are utilized at one medical center to provide the nursing staff for its NICU. The presentation focused on the organization, selection, and development of a nursing staff that is capable of delivering a sophisticated level of care to sick neonates. However, it should be emphasized that it is essential to be alert to changes in patient therapies and related technology that may well alter the practice of neonatal intensive care nursing.

Decision Making↗
PubMed1979

Pharmacologic response to pentobarbital in passively immunized mice.

Rabbits were actively immunized using a barbiturate--BGG conjugate as the immunogen. The antiserum obtained from actively immunized rabbits was administered intravenously to mice to accomplish passive immunization. The antibody binding capacity for 3H-phenobarbital was shown to be sustained in passively immunized mice for periods of up to three weeks. Serum levels of 3H-phenobarbital in passively immunized mice and control mice were compared following drug administration and found to be altered in the antibody-containing mice. There was a 4-fold higher amount of 3H-phenobarbital present in the serum of passively immunized mice compared to control animals. The higher barbiturate levels were due to binding of 3H-phenobarbital to globulin fraction of serum in passively immunized mice. Additionally, decreased pentobarbital-induced ataxia was demonstrated in passively immunized mice. The decreased responsiveness was selective for barbiturates in passively immunized mice and did not modify the ataxia produced in these animals by another depressant agent, ethanol.

Animals↗
PubMed1979

Identification of inosine and hypoxanthine as endogenous ligands for the brain benzodiazepine-binding sites.

Two endogenous ligands for the brain benzodiazepine-binding sites were isolated from bovine brain through gel filtration, paper electrophoresis, and paper chromatography. These ligands were identified as inosine and hypoxanthine, and both had a higher affinity for the brain benzodiazepine-binding sites than for benzodiazepine sites in some peripheral tissues. They did not bind to any other receptors tested, such as the opiate, muscarinic cholinergic, gamma-aminobutyric acid, and beta-adrenergic receptors. Both inosine and hypoxanthine competitively inhibited the binding of [3H]diazepam to the brain binding site.

Animals↗
PubMed1979

Infection with Chlamydia trachomatis: involvement of multiple anatomic sites in neonates.

In a study of infection due to Chlamydia trachomatis in infants, chlamydiae were recovered not only from the conjunctiva and respiratory tract but also from the vagina and rectum. The timing of recovery suggested that the vagina and conjunctivae are exposed to chlamydiae at birth and that pneumonia and gastrointestinal infection occur later. Sampling of the rectum may be a useful procedure for the diagnosis of chlamydial disease in infants.

Chlamydia Infections↗
PubMed1979

Effect of guanethidine on collagen biosynthesis in blood vessels of hypertensive rats.

The effect of guanethidine on collagen biosynthesis in the aorta and mesenteric artery was investigated in desoxycorticosterone acetate (DOCA)-salt hypertensive rats. Prolyl hydroxylase activity (EC 1.14.11.2; proline, 2-oxoglutarate dioxygenase) and 14C-proline incorporation into collagen, two markers of collagen biosynthesis, were significantly increased in blood vessels of hypertensive rats compared with those of controls. When guanethidine (5 mg/kg, i.p.) was given daily to the hypertensive rats for 4 weeks, the blood pressure was decreased to 150 +/- 7 mm Hg, whereas the blood pressure of the untreated hypertensive rats was 218 +/- 10 mm Hg. Prolyl hydroxylase activity in the aorta and mesenteric artery and 14C-proline incorporation into aortic collagen were significantly reduced concomitant with the decrease in blood pressure. These results suggest that the decrease in vascular collagen biosynthesis in hypertensive rats treated with guanethidine is related to the lowering of their blood pressure.

Animals↗