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Biomedical subjects

S Mandel

Publications and source records attributed to S Mandel.

At least 91 records · Page 5Linked to original sources
PubMed1987

Prolactin and antiprolactin receptor antibody inhibit steroidogenesis by purified rat Leydig cells in culture.

The in vitro effects of ovine PRL (oPRL) on testicular testosterone synthesis were determined using isolated, collagenase-dispersed, adult rat Leydig cells in culture. oPRL (50-1000 ng/ml) had no effect either on basal or on LH (50, 100 or 2000 pg/ml)-stimulated testosterone secretion by Leydig cells in short-term culture (4 h). 125I-oPRL binding studies revealed a single class of high affinity sites (Ka 8.7 nM) with a low capacity (Bmax 6.7 fmol/mg protein identical to approximately 980 sites/Leydig cell). Isolated Leydig cells were further purified on a continuous Percoll gradient and cultured in serum-free medium, at 34 degrees C, in 5% CO2 and 95% air. After 3 days of culture, the media were collected, the cells washed and then stimulated with hCG (3 ng/ml) for 3 h. oPRL (1-1000 ng/ml) added at plating, caused a log dose-dependent inhibition of testosterone accumulation during the 3-day culture period; the highest and most consistent inhibition (31%) was with 500 ng/ml oPRL. hCG increased the sensitivity to the inhibitory effect of PRL, 10 ng/ml oPRL causing 40% inhibition and 100 ng/ml causing a maximal inhibition of 50%. PRL in fact caused a reduction in the maximal effect (efficacy) of hCG on steroidogenesis, without significantly affecting the ED50 (sensitivity). The effects of an antiPRL receptor antibody raised by the antiidiotypic route and previously shown to bind to rat testis PRL receptors were tested. The antiPRL receptor IgG (13 micrograms/ml) mimicked the PRL inhibitory effect and acted synergistically with PRL (100 ng/ml) in inhibiting both testosterone accumulation in 3-day cultured Leydig cells and their subsequent response to hCG. In summary, a clear inhibitory effect of PRL and a synergistic effect of antiPRL receptor antibody were demonstrated on testosterone synthesis by rat Leydig cells in 3-day culture.

Animals↗
PubMed1987

Bilateral radial nerve palsy secondary to unilateral blunt shoulder trauma.

We report the case of a 20-year-old black male who developed bilateral radial nerve palsies eight hours after reported blunt trauma to his left shoulder. Pure radial damage was confirmed by electromyography and nerve conduction studies. Recovery was spontaneous and complete without the use of specific therapy.

Accidents, Occupational↗
PubMed1986

Nerve injury complications. Management of neurogenic pain syndromes.

Postural brachial plexus compression neuropathy occurs more frequently than usually realized. The cause is multifactorial with certain predisposing anatomic and congenital factors that are not uncommon. An inciting event is required to cause a clinically significant syndrome. The event can be a specific traumatic episode or cumulative trauma leading to an adoption of a guarding posture, which results in a self-perpetuating cycle and brachial plexus nerve compression. The diagnosis and management may be complicated by concurrent vascular compression, concurrent reflex sympathetic dystrophy, and associated inflammatory musculotendinous conditions. Diagnosis relies on the appreciation of a peculiar symptom complex of pain and paresthesias. The important clinical signs are a supraclavicular Tinel's sign and a positive stress abduction test. Treatment includes exercises, patient education, and behavior modification. However, misdiagnosis can lead to inappropriate treatment, such as unnecessary carpal and cubital tunnel releases. Operative treatment is reserved for those severe cases that are resistant to extended and intense physical therapy. The preferred surgical technique involves an anterior, supraclavicular approach allowing for complete visualization and release of intrinsic and extrinsic nerve compression. Awareness is the key to making the diagnosis, and successful treatment requires a multidisciplinary approach. It is generally accepted that injuries to peripheral nerves result in serious losses of function. Paresthesias and motor weakness cause immediate functional limitation, and place the hand at risk for further injury. The system has little regenerative capacity, and the chance for recovery is poor even under the best circumstances. Therefore the treatment of acute nerve injuries can be difficult and frustrating.(ABSTRACT TRUNCATED AT 250 WORDS)

Brachial Plexus↗
PubMed1985

Chorionic villi sampling: women's attitudes.

To determine the acceptability of chorionic villi sampling (CVS) to women eligible for prenatal diagnosis, we undertook a survey to identify aspects of this new procedure that made it more or less preferable than amniocentesis. All women greater than or equal to 35 years scheduled for amniocentesis were asked to read some detailed descriptive material about amniocentesis and CVS, to rate the importance of the specific differences between procedures, and to indicate which procedure they would prefer, first considering each difference between them independently and then considering all the factors jointly. In the absence of precise estimates of CVS-associated risk at the time of the survey, almost equal proportions preferred amniocentesis and CVS (50.2 and 45.1%, respectively). Risk information was the most important factor to women preferring amniocentesis; the timing of the test or nature of the termination procedure was most important to those preferring CVS. In the hypothetical case where CVS was stipulated to have the same attributable risk as amniocentesis, 82% of respondents would prefer it. However, if the spontaneous abortion rate following CVS was stipulated to be 5% more than the amniocentesis risk, preferences reversed and only 22% would still prefer it. Thus, the data suggest that the ultimate acceptability of the new procedure for women over 35 years seeking prenatal diagnosis will depend on the risk associated with it and underscore the importance of ongoing trials aimed at establishing this risk.

Abortion, Induced↗
PubMed1984

Recurrent rhabdomyolysis as a manifestation of alcoholic myopathy. Report of a case.

A 38-year-old man experienced six severe episodes of rhabdomyolysis and two episodes of pharyngeal muscle weakness superimposed on chronic alcoholic myopathy and complicated by cardiomyopathy. A muscle biopsy specimen demonstrated sharply reduced levels of electrolytes despite normal serum values; presumably, these deficiencies were related to the pathogenesis of the recurrent rhabdomyolysis.

Adult↗
PubMed1983

Tyrosine supplementation in chronic experimental uremia.

The occurrence of low tyrosine tissue levels in uremic subjects, possibly due to impaired phenylalanine hydroxylation, suggests that tyrosine may be an essential amino acid in uremia. Additional dietary tyrosine may thus re-dress the deficiency. This study examined growth and tyrosine/phenylalanine metabolism in uremic rats during tyrosine supplementation. Rats made uremic (U) by 7/8 nephrectomy were compared to pair-fed (CP) and ad libitum-fed (CA), sham-operated controls. Two sets of each group of rats were studied after 21 days on the respective diets: I = Purina Lab Chow; II = same + 3.5% tyrosine. Plasma tyrosine was below normal in U and CP-fed diet I. With diet II, the tyrosine:phenylalanine ratio in U was lower than both CA and CP. In rats fed diet II, the tyrosine:phenylalanine ratio became indistinguishable among the three groups. Growth parameters in U and CP were similar, regardless of the diet. Body weight gain, tibial length, muscle mass, and tissue protein did not improve in uremic animals supplemented with tyrosine. The specific activity of liver phenylalanine hydroxylase in U was not different from CA or CP. However, loss of cortical renal mass appeared to be the major determinant of decreased kidney phenylalanine hydroxylation in experimental uremia. This alteration is likely to be the greatest contributory factor to the alteration of plasma levels of tyrosine and phenylalanine. The data presented do not support a proposed essentiality of tyrosine in uremia.

Animals↗
PubMed1983

Pulmonary function in paracoccidioidomycosis (South American blastomycosis). An analysis of the obstructive defect.

Comparison of the mean results of routine pulmonary function studies of 17 patients with diffuse pulmonary paracoccidioidomycosis (PM) and manifestations of chronic obstructive pulmonary disease (COPD) to those of 17 matched patients with pure COPD showed no significant differences. These findings were interpreted as fresh evidence suggesting that expiratory obstruction in PM may be secondary to underlying COPD. Other evidence to that effect is discussed.

Female↗
PubMed1983

Anticonvulsants and neurogenic pulmonary edema.

A patient with a seizure disorder since childhood was poorly compliant with anticonvulsant medication. He died suddenly following a seizure secondary to a rapid decrease in plasma anticonvulsant drug levels. Autopsy demonstrated pulmonary edema. This noncardiac form of pulmonary edema has been related to low anticonvulsant drug levels in many epileptics who die suddenly. Patients receiving anticonvulsant medication must make no change in drug dosage without medical guidance because of the risk of this catastrophic consequence.

Adult↗
PubMed1982

Steroid myopathy. Insidious cause of muscle weakness.

Steroids are so commonly prescribed for so many conditions that physicians tend to become somewhat cavalier in their use. With drug therapy of any type, however, this tendency can lead to trouble. Steroid myopathy, as occurs in Cushing's syndrome. Can develop with steroid therapy and can cause irreversible atrophy if not detected and treated early.

Adrenal Cortex Hormones↗
PubMed1980

Tenckhoff peritoneal dialysis catheter: cannulography and manipulation.

The Tenckhoff catheter is a permanently implanted peritoneal access cannula widely used for acute or chronic peritoneal dialysis. Failure of the cannula is usually due to the development of blocking adhesions or malposition. In 14 of 18 patients with inadequately functioning Tenckhoff catheters, catheter manipulation resulted in restoration of function. There were no complications.

Adolescent↗