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Biomedical subjects

S M Feldman

Publications and source records attributed to S M Feldman.

At least 19 recordsLinked to original sources
PubMed1989

The nucleus locus coeruleus modulates local cerebral glucose utilization during noise stress in rats.

Local cerebral glucose utilization (LCGU), estimated by the quantitative autoradiographic 2-deoxyglucose technique, was studied in rats with bilateral 6-hydroxydopamine lesions of the locus coeruleus (LC) and in vehicle-injected controls. Unanesthetized animals were studied during exposure to stressful levels of white noise (95 dB) or in relative silence (50 dB). Results indicated that noise caused greater and more widespread increases in LCGU in animals with LC lesions than in vehicle-injected controls. Lesions alone had little or no effect in animals not subjected to noise. Analyses of variance revealed significant treatment interaction effects (intact/lesion x silence/noise) for 37 of 109 regions measured. The pattern of results suggests that the LC acts during stress to limit unnecessary cerebral activity that might interfere with efficient sensory processing and/or the organization of appropriate behavioral responses. In this respect LC function may be similar to those actions of the peripheral sympathetic nervous system that suppress vegetative functions during stress to allow for the performance of coping responses.

Animals↗
PubMed1989

Evaluating the anti-plaque capabilities of a copper-containing prophylaxis paste.

The purpose of this study was to evaluate a dental prophylaxis paste containing mono-copper citrate (MCC) for short term anti-plaque capabilities. In addition to other baseline data, plaque scores were recorded on 36 paid volunteer subjects from the dental school student, staff, and faculty populations. After scaling, two quadrants of each subject's dentition were polished with the MCC containing paste and two quadrants with the placebo paste, using a diagonal split mouth double blind design. Subjects did not brush or floss for two days. Plaque scores were recorded at 24 and 48 hours, after which they resumed normal hygiene. Results showed that after 24 hours placebo areas had 92% higher plaque and after 48 hours 33% higher plaque than the active paste areas. This was statistically significant at the P less than .001 level. The diminishing effect of the copper containing prophy paste over 48 hours might indicate that the copper ion should be applied on a daily basis for best anti-plaque results.

Citrates↗
PubMed1987

Functional neuroanatomic mapping of the rat striatum: regional differences in glucose utilization in normal controls and after treatment with apomorphine.

Glucose utilization was measured in 5 regions of rat striatum within four anterior-posterior levels. Areas of minimal and maximal glucose utilization were identified. Density-window image analysis was used to quantify areas of minimal and maximal glucose utilization, which were also apparent upon close visual inspection. In a normal control group, there were substantial regional variations in striatal glucose utilization (e.g. dorsal vs ventral; dorsomedial vs dorsolateral), revealing a detailed pattern, previously unavailable, which served as a baseline to study the effect of systemic apomorphine. The highest levels of glucose utilization were in small islands 0.01-0.25 mm2, and in what appeared to be dense clusters of islands that formed larger zones. Apomorphine treatment decreased glucose utilization in dorsomedial regions, increased it in a ventromedial region, and did not change it in others. The findings emphasize the importance of regional analysis of striatum in functional and physiological studies, and provide a new baseline for analyses of striatal glucose utilization in studies of development and aging, drug effects, external stimuli, and rat models of movement disorders.

Animals↗
PubMed1978

Microvascular responses to norepinephrine and vasopressin during halothane anesthesia in the rat.

This experiment was designed to determine the microvascular responses to the two known naturally occurring vasoconstrictors, norepinephrine (NE) and vasopressin, at known levels of central vasomotor activity before, during and after halothane anesthesia. The responses to topical application of NE and vasopressin were studied in the microvasculature of the mesentery and cremaster muscle, using microscopic methods. Neural (CNS) stimulation was accomplished through electrodes chronically implanted in vasoactive sites of the forebrain and midbrain. The increase in blood pressure in response to CNS stimulation was decreased during halothane anesthesia (32.4 +/- 5.4 per cent before and 24.7 +/- 6.1 per cent during; P less than 0.001). There was no significant change in the steady-state diameter of the microvasculature under study during or after halothane anesthesia. Marked abatement of arteriolar vasoconstriction in response to CNS stimulation was seen prior to halothane. However, the same target vessel showed increased constriction in response to topically applied NE (from 32.3 +/- 4.7 to 53.2 +/- 7.8 per cent; P less than 0.01) during halothane anesthesia. By contrast, the response to vasopressin decreased (from 42.4 +/- 5.7 to 1.0 +/- 6 per cent; P less than 0.001) with halothane. The precise mechanism(s) underlying the described hypersensitivity to NE and hyposensitivity to vasopressin in the same vascular structure during halothane anesthesia remains undetermined.

Animals↗
PubMed1977

Central neural influence on precapillary microvessels and sphincter.

The responses to central nervous system (CNS) stimulation of consecutive segments of arterioles down to the precapillary sphincter were measured in the mesoappendix and/or cremaster of nine male rats with indwelling electrodes. Under pentobarbital sodium anesthesia, vasoactive sites were stimulated at threshold for maximal constriction or lumen closure of the precapillary sphincter and/or immediately preceding precapillary arteriole (metarteriole). In all experiments, CNS stimulation induced blood pressure elevation and constriction of three consecutive segments of precapillary vessels and of the sphincter. A threefold increase in rate of vasomotion of precapillary sphincter and metarteriole was the rule, but this was noted infrequently in larger arterioles. In addition to an overall influence of the CNS on microcirculation, the data show a gradient of responses to stimulation, the slope of which is negatively related to the size of the vessels and sphincter, in both tissues studied. A complete lumen closure of the metarteriole and precapillary sphincter (when present) in response to CNS stimulation implies active participation in the regulation of local blood flow. No evidence was foun for central neural regulation of the precapillary sphincter independent of arteriolar control.

Abdominal Muscles↗
PubMed1977

Course evaluation by committee.

An intradepartmental course evaluation committee has been established in the Department of Community Dentistry at the University of Louisville School of Dentistry. This committee's review of student evaluation mechanisms was a major focus in the assessment of all departmental courses. An evaluation technique, based on a comparison of existing student evaluation mechanisms against criteria established by the committee and approved by the departmental faculty, was designed and applied. The committee was viewed as successful by departmental course directors; however, its suggestions were not widely implemented by the departmental faculty. Several reasons are cited for this, as well as suggestions for future modifications of the committee's procedures.

Curriculum↗
PubMed1975

Reversal of hypercoagulable state by bilateral nephrectomy.

The hypercoagulable state associated with select cases of glomerulonephritis is difficult to diagnose by standard laboratory techniques but is clinically manifested by recurrent shunt and fistula thrombosis which may be refractory to anticoagulant therapy. Bilateral nephrectomy reversed this hypercoagulable state. After renal allograft, however, the patient experienced hyperacute rejection, and transplant nephrectomy was required to cure the recurrent hypercoagulable state. The mechanism of this previously unreported phenomenon and its implications with regard to renal transplantation are discussed.

Adult↗