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Biomedical subjects

D S Feldman

Publications and source records attributed to D S Feldman.

At least 19 recordsLinked to original sources
PubMed1993

Localization of cholinergic neurons involved in the cardiovascular response to intrathecal injection of carbachol.

Recent studies in this laboratory have demonstrated the ability of acetylcholine receptor agonists to produce systemic arterial pressor responses through stimulation of spinal muscarinic receptors. In urethane-anesthetized rats a new surgical procedure was employed to permit microinjection of drugs into the cerebrospinal fluid surrounding the medulla without significant redistribution to spinal sites and vice versa. Pretreatment with intracisternal (medullary level) injection of 10 micrograms of atropine significantly inhibited the expression of the pressor response produced by intrathecal injection of 5 micrograms of carbachol. This inhibition was due at least partly to the interruption of a medullary component of a spinobulbar pathway involving medullary muscarinic receptors. It was not due to redistribution of atropine from medullary to spinal sites since significant levels of atropine were not detected in the spinal cord after intracisternal injection of the drug. The remainder of the pressor response to intrathecal carbachol after medullary muscarinic receptor blockade was most likely due to interactions within the spinal cord itself.

Animals↗
PubMed1993

Plasma ascorbic acid concentrations relate inversely to blood pressure in human subjects.

This study relates antioxidant status and blood pressure (BP) in 168 healthy residents of Augusta, GA, following usual diets. BP ranges were systolic (S) 84-152, mean 112 +/- 1 mm Hg, and diastolic (D) 52-96, mean 72 +/- 1 mm Hg. Plasma concentrations of ascorbic acid (AA) were significantly inversely related to SBP (r = -0.18, P < 0.05) and DBP (r = -0.20, P < 0.01); with regression equations SBP vs AA = -0.083C + 116 and DBP = -0.077C + 76. Highest and lowest quintiles of AA differed significantly in mean SBP (108 +/- 2, 113 +/- 2 mm Hg) and DBP (69 +/- 1, 74 +/- 2), P < 0.05. Plasma AA concentrations were significantly lower in the smokers. By deleting smokers, the inverse relations of SBP and DBP with plasma AA and the slopes of the equation were enhanced. Plasma selenium, alpha-tocopherol, alpha-tocopherol:cholesterol ratio, retinol and taurine were not related to BP; whereas male gender, body mass index, body fat distribution, plasma cholesterol, low density lipoprotein cholesterol, and triglycerides correlated.

Adipose Tissue↗
PubMed1993

Clinical efficacy of aspirin and dextran for thromboprophylaxis in geriatric hip fracture patients.

The clinical efficacy of thromboprophylaxis with aspirin and dextran 40 was compared in a prospective review of 530 geriatric hip fracture patients treated surgically. All patients were also treated with early mobilization with weight bearing as tolerated and above-knee elastic stockings. In addition to clinical efficacy in preventing thromboembolic complications [deep vein thrombosis (DVT), pulmonary embolism (PE)], safety and cost-effectiveness were also assessed. The overall incidence of clinical thromboembolic disease was 2.8% (DVT = 0.4%, PE = 2.4%). The incidence of DVT (0.5%) and PE (2.6%) in the aspirin group was essentially the same as the incidence of DVT (0.3%) and PE (2.4%) in the dextran group. The inhospital mortality rate (aspirin 4.6%, dextran 3.8%), wound drainage (aspirin 1.5%, dextran 0.9%), deep wound infection (aspirin 0.5%, dextran 0.3%), gastrointestinal bleeding (aspirin 2.1%, dextran 1.5%), and congestive heart failure (aspirin 2.6%, dextran 1.8%) did not differ significantly between the two groups. The intraoperative transfusion rate was similar in both groups (aspirin .65 units, dextran .55 units). However, postoperatively, the transfusion rate was significantly higher in the dextran group (aspirin .26 units, dextran .41 units, p < .05). The treatment of thromboembolic complications was the same for each group and therefore represents similar treatment costs. However, the cost of prophylaxis with dextran was $309 per patient and with aspirin was $1.79 per patient. Our findings suggest that, based on clinical diagnostic criteria, aspirin and dextran are equally effective thromboembolic prophylactic agents in geriatric hip fracture patients. The safety, cost, and ease of administration of aspirin may make its use more desirable.

Aged↗
PubMed1993

Cognitive and neurologic deficits in the MRL/lpr mouse: a clinicopathologic study.

OBJECTIVES: Determine if the MRL/lpr mouse develops neurological deficits and, if so, the pathologic basis for these deficits. Antiphospholipid antibodies (aPL) are associated with ischemic stroke, multiinfarct dementia, chorea, and cardiac valvular abnormalities. The MRL/lpr mouse develops high titer anticardioplin antibodies (aCL) suggesting that it may be used as a model for the neurological complications of aPL. METHODS: We undertook a prospective clinicopathologic study comparing the MRL/lpr mouse against its congenic strain, the MRL/+ mouse. We studied 15 MRL/pr and 15 MRL/lpr and 15 MRL/+ mice at 16 to 20 weeks and a group of 16 mice of each strain at 8 to 10 weeks. aCL and anti-DNA antibodies were measured by ELISA: Cognitive and neurological deficits were assessed by a water maze and a standardized rodent neurological examination. The brains and cardiac valves of the mice were then examined pathologically. RESULTS: The MRL/lpr mice had significantly elevated aCL at both ages. Cognitive and sensorimotor deficits were apparent at 16 weeks but no correlation could be found with aCL or anti-DNA titer. Even at 8 weeks the MRL/lpr mice performed poorer on the water maze when compared to their age matched congenic strain. No evidence of cerebral infarction was found but mononuclear infiltrates were found in the choroid plexus of all the MRL/lpr mice at both 10 and 20 weeks. No evidence of cardiac valve pathology was seen at 20 weeks. CONCLUSIONS: (1) The MRL/lpr mouse develops cognitive and neurologic deficits. The etiology of these deficits is not clear but may be related to early infiltration of the central nervous system with mononuclear cells. (2) Despite the elevated aCL, evidence of cerebral infarction or mitral valve abnormalities could not be found.

Animals↗
PubMed1992

Vitamin A in hypercholesterolemia.

This study evaluated the relationship between plasma vitamin A and cholesterol in 48 patients with hypercholesterolemia studied before and after treatment with a cholesterol-lowering diet, with or without lipid-lowering medication. Plasma vitamin A levels were higher in hypercholesterolemic subjects than in healthy controls (2.58 +/- 0.15 vs. 1.82 +/- 0.14 mmol/L, p = 0.025) despite similar values for retinol binding protein (RBP). Successful cholesterol lowering, defined as greater than 25% reduction in low density lipoprotein cholesterol, was achieved in 16 patients. In this subset, plasma vitamin A declined from 3.00 +/- 0.32 (pretreatment) to 2.34 +/- 0.15 mmol/L (post treatment; p = 0.018). A nonsignificant increase in RBP was observed, resulting in a significant decrease in the molar ratio of vitamin A to RBP (1.05 +/- 0.06 vs. 0.80 +/- 0.05, p = 0.013). These data suggest an interaction between vitamin A and cholesterol that is independent of the transport mechanisms for vitamin A in association with chylomicrons (post absorptive) and with RBP. Further examinations of the form or forms of vitamin A (retinol, retinyl ester), its distribution within the plasma lipoproteins, and the mechanisms of origin and removal are warranted to explain these findings.

Anticholesteremic Agents↗
PubMed1991

Quantification of vascular ingrowth into Dacron velour.

Evaluation of vascular ingrowth into Dacron velour was performed to compare methods and to determine the amount of vascular ingrowth. Microcasting and direct measurement were compared based on their ability to quantify ingrowth, the type of information obtainable, and the time required for data acquisition. Microcasting did not produce results indicative of the actual vascular ingrowth; however, direct measurement of histological slides gave quantifiable data for comparing vascular ingrowth.

Animals↗
PubMed1990

Effects of seizures on learning, memory, and behavior in the genetically epilepsy-prone rat.

To determine whether frequent seizures can cause deficits in learning and behavior, immature genetically epilepsy-prone rats (GEPRs) were subjected to 66 audiogenic stimulations (Group 1). GEPR littermates were handled and placed in the sound chamber but were not stimulated (Group 2). Group 3 comprised genetically epilepsy-resistant rats (GERRs) who received audiogenic stimulations but had no seizures. After 3 weeks of stimulations the rats were tested for learning, memory, and behavior using the T-maze, water maze, open field activity test, home cage intruder test, and handling test. When compared with the control GEPRs and GERRs, Group 1 rats reached criteria less frequently in the T-maze, required longer times to find the platform in the water maze, and were less active in the open field activity test, less aggressive in the home cage intruder test, and more irritable and aggressive in the handling test. This study demonstrates that frequent, brief seizures in immature animals result in significant detrimental changes in learning, memory, activity level, and behavior.

Acoustic Stimulation↗
PubMed1990

Biochemical, endocrine, and mineral effects of indapamide in black women.

Black women with established essential hypertension, without renal insufficiency or diabetes mellitus, were withdrawn from their usual antihypertensive therapy for 2-3 weeks prior to entry into a study to evaluate pertinent biochemical and mineral effects of indapamide treatment. Twenty patients with a sitting diastolic blood pressure greater than 90 mm Hg had baseline measurements of plasma total cholesterol, HDL cholesterol, triglycerides, glucose, uric acid, potassium, magnesium, calcium, selenium, renin, norepinephrine, whole blood ionized calcium, and glycosylated hemoglobin. Low-density lipoprotein (LDL) cholesterol was calculated by the Friedewald equation. The patients were placed on a fixed daily dose of 2.5 mg indapamide. Blood pressure and blood tests were repeated at 4, 8, and 12 weeks of treatment. The systolic and diastolic blood pressure were both lowered significantly at week 12. Plasma renin activity was significantly increased. There was no significant change in norepinephrine, glucose, glycosylated hemoglobin, uric acid, ionized calcium, calcium, triglycerides, potassium, magnesium, or selenium. Total cholesterol increased with an increase in both high-density lipoprotein (HDL) and LDL cholesterol; however, these increases did not alter significantly either the total/HDL cholesterol or LDL/HDL cholesterol ratios. It is concluded that 2.5 mg of indapamide per day effectively lowers blood pressure with no significant adverse metabolic effects.

Adult↗
PubMed1990

Intraluminal bypass device for arterial surgery.

Over 50,000 artificial grafts are implanted every year in the United States. Present surgical procedures require either bypass or clamping off of the vessel to be replaced. Complications of these techniques include aneurysms and left ventricular overload. In addition, for aortic procedures paraplegia or even death can occur. A simple surgical procedure that does not require cardiopulmonary bypass, external shunts, or cross-clamping was developed and tested in dogs. An intraluminal bypass device was developed to allow blood to flow through the aorta to the lower limbs during the procedure. Blood flow stoppage was minimized, which should lead to a reduction of morbidity and mortality.

Animals↗
PubMed1989

Creation of a regional medical-nutrition education network.

The Southeastern Regional Medical-Nutrition Education Network (SER-MEN) was developed to coordinate and improve nutrition education in a consortium of the medical schools in Alabama, Florida, Georgia, and South Carolina. SERMEN's central office is at the Medical College of Georgia with the testing office at the University of Alabama at Birmingham. Students, faculty, and consultants in nutrition, education, and computer networking work together on projects on each campus that are coordinated and planned through semiannual meetings. A standardized examination was developed with the Nutrition Test-Item Bank to assess nutrition knowledge at various years of medical students from network schools. Each SERMEN school is connected to a microcomputer system at the central office that provides access to a data base of nutrition education and resources on each campus for developing curricula and syllabi. Funding has been provided by societies, foundations, and government agencies.

Computer Communication Networks↗
PubMed1989

Trace element status in multiple sclerosis.

We compared trace element status in multiple sclerosis (MS) patients (n = 27) with and without treatment with corticosteroids and groups of healthy subjects. Concentrations of plasma ceruloplasmin, selenium, and zinc and erythrocyte (RBC) glutathione peroxidase, Se, and Zn were similar in all groups. RBC copper concentrations were significantly lower in MS patients than in control subjects (mean +/- SEM: 0.048 +/- 0.005 vs 0.060 +/- 0.002 mumol/g Hb) because of decreased RBC Cu with steroid therapy. RBC Zn-Cu ratios were significantly higher (14.9 +/- 1.0 vs 10.1 +/- 0.3) in MS patients than in control subjects, differing in both groups of MS patients. In MS and control subjects, RBC Cu correlated significantly with RBC Zn (r = 0.56, 0.49). Disease acuity and disability had no effect on trace-mineral status. These data suggest that in MS there is altered Cu and Zn homeostasis that may cause or result from the disease and is influenced by corticosteroid therapy. Systemic trace element alterations might provide clinically useful markers of MS.

Adolescent↗
PubMed1989

Plasma lipoproteins in cortical versus lacunar infarction.

We investigated the relation of plasma lipids to the risk for ischemic stroke by comparing clinical and biochemical characteristics of survivors of cortical (n = 48) and lacunar (n = 36) brain infarction. By analysis of variance, no differences were observed in the concentrations of total cholesterol, triglycerides, low density lipoprotein cholesterol, very low density lipoprotein cholesterol, or apoproteins A1 and B. Patients with lacunar infarction, however, had higher concentrations of high density lipoprotein (HDL)-cholesterol than patients with cortical stroke. This HDL-cholesterol difference was due primarily to a strikingly low HDL-cholesterol content in white patients with cortical stroke. These data suggest that previously demonstrated differences in HDL-cholesterol concentrations between patients with ischemic stroke and control subjects without stroke may apply to patients with cortical but not lacunar infarction. Separation of cerebral infarction into subtypes based on mechanism may help clarify lipid-related risk factors in cerebrovascular disease.

Age Factors↗
PubMed1988

In vivo probe of central cholinergic systems.

Age-related cognitive impairments and dementia of Alzheimer type have been linked to alterations in the cholinergic system. In the present study, evoked potentials and neuropsychological testing were obtained in healthy subjects during neuropharmacological manipulations including: scopolamine (anticholinergic), scopolamine plus physostigmine (anticholinesterase), scopolamine plus methylphenidate (adrenergic), and placebo. Scopolamine prolonged P3 latency and reduced spectral power of long latency evoked potentials without significantly altering earlier components. Physostigmine partially reversed these effects, but methylphenidate did not. Motor speed was slowed by scopolamine, but not by scopolamine plus methylphenidate. Cholinergic systems appear to be involved in generation or modulation of the P3 potential, possibly secondary to the cholinergic role in selective attention. Similar techniques may be useful as in vivo probes of central cholinergic function and thus as research and diagnostic aids in aging and disease.

Adult↗
PubMed1988

A comparison of three techniques to quantify vascular ingrowth into Dacron velour.

Three methods of evaluation of vascular ingrowth into treated and untreated Dacron velour were performed to compare the methods. Vascular casting, direct measurement, and stereology were compared based on their ability to quantitate ingrowth, the type of information obtainable, and the time required for data acquisition. Results show that with the methods used in this study vascular casting was not able to produce data indicative of the actual vascular ingrowth. Direct measurement and stereological measurements of histological slides were able to give hard data for comparing ingrowth. However, stereological measurements were easier and less time-consuming to perform. In addition, stereological measurements were able to reveal additional parameters quickly.

Animals↗
PubMed1987

Auditory P3 correlates of phonemic and semantic processing.

Auditory evoked potentials were recorded in twelve healthy subjects using phonemic and semantic word tasks. The late positive component (P3), analogous to tonal P300, varied as a function of cognitive task with increased latency and amplitude associated with semantic processing. These data are consistent with levels of processing theories in which semantic analysis is associated with a greater elaboration of stimulus evaluation.

Adult↗
PubMed1986

Selenium status of malnourished hospitalized patients.

We evaluated selenium (Se) status of 44 hospitalized patients with protein-energy malnutrition. The patients were assigned to "normal" or "low" Se groups-1 and 2, respectively-based on whether the plasma Se level exceeded or was below the value of the mean-2SD of healthy Georgians'. Plasma and erythrocyte Se levels correlated significantly (r = .52, P less than .01). Erythrocyte glutathione peroxidase activity was highly correlated with plasma Se (r = .68) in group 2; there was no significant correlation between these parameters in group 1. In group 2 the mean plasma prealbumin level was significantly lower, and the mean corpuscular volume and serum glutamic oxaloacetic transaminase level were significantly higher compared to group 1. Other nutritional parameters did not correlate with Se status. Concomitant deficiencies of other nutrients were common in both patient groups. Se levels may relate to protein status, and abnormal hematologic and hepatic parameters may reflect low Se status and/or protein-energy malnutrition. Low Se status is common in malnourished patients from a low Se area, and Se supplementation should be included in their nutritional-repletion regimens.

Adult↗