Search PubMed⌕ Search

Biomedical subjects

J Feldman

Publications and source records attributed to J Feldman.

At least 199 records · Page 11Linked to original sources
PubMed1986

An endogenous, non-catecholamine clonidine antagonist increases mean arterial blood pressure.

We report here that topical application of clonidine displacing substance (CDS), an endogenous brain extract, directly in the nucleus reticularis lateralis (NRL) region of anaesthetized cats regularly produced hypertension. CDS (5 units) increased the mean blood pressure by 40 +/- 8%. Pretreatment of anaesthetized rabbits with intracisternal CDS (500 units) shifted to the right the dose-response curve obtained with clonidine alone injected the same way. This brain extract might be considered as an endogenous antagonist for the hypotensive effects of clonidine at least in the NRL region.

Animals↗
PubMed1986

Effect of glucose and fat feeding on norepinephrine turnover in rats.

The norepinephrine turnover in organs of glucose-fed and fat-fed rats were compared to those of starved rats. Rats fed only glucose had higher rates of norepinephrine turnover than starved rats in heart, pancreas, kidney, liver, and lung. The effect of glucose-feeding on norepinephrine turnover was most pronounced in heart (+197%) and pancreas (+120%), which were examined in the fat feeding study. Rats fed only fat showed the same suppression of insulin levels as fasting rats, and a greater reduction in plasma glucose levels. However, their norepinephrine turnover in heart (+182%) and pancreas (+173%) was similar to that of glucose-fed rats. Thus glucose and fat increase norepinephrine turnover in the absence of any other nutrients. If these nutrients increase norepinephrine turnover via the same intermediate signal, it cannot be insulin or increased glucose metabolism.

Animals↗
PubMed1986

Second year medical student opinion about public health and a second year course in preventive medicine and community health.

The results of five annual surveys of second year medical students over an eight year period of time (1978-1985) concerning perceptions and attitudes toward public health and a course in preventive medicine and community health are presented. The questionnaire format was a combined fixed alternate and free response type and was structured to require only ten to 15 minutes for its completion. Participation rates were generally high varying from 60.2% (1980) to 93.8% (1985). The majority of students in all years favorably evaluated most components of structure, content and presentation of the course. It was found that opinions about the course can be modified by the introduction of variables that are unrelated to the scope of the quality of the course as occurred in 1979, with a difficult midterm examination. Student anger over this examination was translated and expressed as negative opinion about many other aspects of the course which in other years were highly rated. This finding underscores the vulnerability of surveys of subjective opinion and demonstrates that course evaluations must include other objective aspects in addition to student perceptions.

Attitude of Health Personnel↗
PubMed1986

[Double-blind study of the treatment of disc lumbosciatica by chemonucleolysis].

A randomized, double-blind study was made of 39 patients with discolumbar hernias that were unresponsive to medical treatment. They were treated either by nucleolysis with chymopapain (4 000 U of discase), or by discography followed by injection of distilled water as a placebo. After one month, treatment was found to be successful in 55% of cases undergoing nucleolysis and in 26% of cases receiving the placebo. The results after 3 months were 65% and 42%. respectively. After one month, the intensity of lumbar pain decreased by 44% on average in the group treated by chymopapain, and by 0% in the placebo group. Radicular pain decreased by 53% in the first group and by 26% in the placebo group, and improvement in Lasègue's sign was 51% and 20%, respectively. Analgesic treatment was reduced in patients treated by chymopapain: 65% of patients in the first group report some or much improvement in their sciatica, whereas this figure was 26% in the placebo group (p less than 0.02). Contralateral sciatica was observed in 3 patients of the placebo group. The average give in the disc one month after nucleolysis was 34% in the chymopapain group and 27% in the placebo group, without correlation with the clinical result. On average, patients were monitored for one year after nucleolysis, and during this year 6 patients from the chymopapain group were operated upon, compared with 10 patients from the placebo group. Although these results are at the limit of statistical significance because of the number of patients studied, they confirm the innocuousness and effectiveness of chymopapain in the treatment of discolumbar hernias.

Adult↗
PubMed1985

Tissue hypoxia distal to a Peñaz finger blood pressure cuff.

The Peñaz finger method to measure blood pressure uses a finger cuff in which the pressure level fluctuates in the vicinity of the mean arterial pressure level and thereby interferes with the circulation of blood to and from the fingertip. We measured capillary blood gases and saturation of hemoglobin in the finger during Peñaz finger blood pressure (PFBP) monitoring to assess the degree to which it impairs circulation in the fingertip. Within 2.5 minutes after initiating PFBP monitoring, capillary oxygen tension (PO2) had decreased significantly, from about 71 mm Hg to between 49 and 58 mm Hg for up to 50 minutes. These changes were quite different from those occurring when an occlusive tourniquet was applied around the finger. Within 10 minutes of tourniquet application, acidosis (pH 7.25), hypercapnia (carbon dioxide tension, 59.0 mm Hg), and hypoxemia (PO2, 29 mm Hg) resulted. Within 30 seconds of releasing the PFBP cuff, capillary blood gas values were back to normal. Interspersing 30-second rest periods every 5 minutes during 35 minutes of PFBP monitoring actually decreased capillary oxygen values compared with monitoring without such rest periods. A finger pulse oximeter distal to the PFBP cuff showed desaturation from an average of 97% to 93.7%, with much variability. However, desaturation was statistically significant within 1 minute of application of the PFBP cuff. Within 1 minute the finger volume increased an average of 0.05 ml. After 1 minute the volumes varied widely and, on the average, returned to normal despite continued PFBP monitoring.

Acidosis↗
PubMed1985

The medullary cardiovascular effects of imidazolines and some GABA analogues: a review.

A study of the localizations and mechanisms of the hypotensive action of clonidine-like substances and GABA analogues. It is confirmed that these agents act on the ventral surface of the medulla oblongata and are involved in the central control of the cardiovascular system. Suggestions are offered relative to the development of new centrally acting antihypertensive agents.

Animals↗
PubMed1985

Obligate amoebae of the protostelids: significance for the concept of Eumycetozoa.

Most flagellate Eumycetozoa have a non-flagellate, or obligately amoeboid, trophic state which differentiates from the amoebo-flagellate state and gives rise to the fruiting body. This study examines the morphology, general ultrastructure, and microtubular systems of the obligate amoebae of three flagellate protostelids with typical amoebo-flagellate states. The obligate amoebae of all three species are morphologically distinct indicating that the obligately amoeboid state has evolved independently in the history of each species. Therefore, obligate amoebae may be useful for defining separate evolutionary groups within the Eumycetozoa.

Biological Evolution↗
PubMed1985

On the mechanism of the hypotensive action of urapidil.

The cardiovascular effects of urapidil have been investigated in the anaesthetized rat and cat. Intravenous (i.v.) urapidil produced a significant hypotension without change in heart rate. Directly injected into the brain cavities, urapidil produced a hypotensive effect only at very high doses (1 mg/kg) in normotensive and spontaneously hypertensive rats. In cats, however, intracisternal (i.c.) injection of urapidil produced hypotension at doses of 30 and 100 micrograms/kg. In this species, a central component to the hypotensive effect of the drug is therefore possible. However, urapidil antagonized competitively the contraction of the rat aorta induced by noradrenaline. The drug has alpha-adrenoceptor blocking properties, which probably mainly explain its hypotensive action. On the other hand, urapidil induced a presynaptic inhibition in the heart, which may explain the lack of heart rate changes during the hypotensive effect of the drug. Urapidil may therefore stimulate presynaptic alpha 2-adrenoceptors in the heart as well as in the vas deferens.

Animals↗
PubMed1985

Retrenchment. How nurse executives cope.

Changing economic, technicologic, and political conditions have created the need for readjustments in the number of nursing personnel employed by hospitals. The authors examined how nurse executives conducted themselves and managed their personnel during layoffs.

Adaptation, Psychological↗
PubMed1984

Risk factors for prematurity and premature rupture of membranes: a prospective study of the vaginal flora in pregnancy.

Prematurity remains a major cause of perinatal mortality in the United States. Some research has indicated that infectious agents play a role in either initiating preterm labor, causing premature rupture of the membranes, or preventing tocolysis. This study attempted to determine if the presence of various vaginal pathogens in early pregnancy was associated with the subsequent development of premature rupture of membranes or preterm labor. We found that among 233 evaluable patients those with Trichomonas vaginalis were significantly more likely to have premature rupture of the membranes (p less than 0.03), and those with Bacteroides sp. were more likely to be delivered of their infants before 37 weeks (p less than 0.03) and to have infants weighing less than 2500 gm (p less than 0.05). Those with Ureaplasma urealyticum more frequently began preterm labor (p less than 0.05). Preterm premature rupture of the membranes was found significantly more often among patients with Bacteroides sp. Stepwise multiple logistic regression analysis indicated that those associations were not related to the number of previous abortions, deliveries, or preterm deliveries or to maternal age. We conclude that microbiologic screening in early pregnancy may aid in the assessment of patient risk for preterm delivery.

Adolescent↗
PubMed1984

The effects of ouabain in the medullary site of the hypotensive action of clonidine.

Blood pressure was studied in pentobarbital anesthetized rats and cats after central administration of ouabain. Intracerebroventricular (i.c.v.) injections caused a classical biphasic effect, a short lasting hypotension followed by a hypertensive phase. When injected directly into the nucleus reticularis lateralis region (NRL), ouabain (0.01-2 micrograms/kg) caused a dose-dependent pressor effect. In the same region, kryptofix 221, a sodium complexing agent, produced a fall in blood pressure. Moreover, central administration of ouabain prevented the hypotensive effect of i.v. clonidine whereas the central hypotensive effect of muscimol was not affected. It is concluded that sodium movements play an important role in the blood pressure regulation within the NRL region. We also report here that ouabain antagonizes the hypotensive effect of clonidine suggesting that sodium movement might be the essential link of this action.

Animals↗
PubMed1984

TAG antagonises the central cardiovascular effects of taurine.

The taurine antagonist TAG was examined for its blocking activity towards the central cardiovascular effects of taurine and muscimol. Intracerebroventricular (i.c.v.) injections of taurine (1-1000 micrograms/kg) and muscimol (0.1-3 micrograms/kg) in the anesthetised cat led to hypotension and bradycardia. Pretreatment with TAG (1 mg/kg i.c.v.) antagonised the blood pressure effects of taurine. The selectivity of this antagonism is discussed since TAG also shifted to the right the blood pressure dose-response curve obtained with muscimol.

Animals↗