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Biomedical subjects

S Mandel

Publications and source records attributed to S Mandel.

103 records · Page 6Linked to original sources
PubMed1979

Indicator dilution measurement of 5-hydroxytryptamine clearance by human lung.

A double indicator dilution method to measure 5-hydroxytryptamine (5-HT) clearance by lungs of anesthetized patients is described. Immediately after a bolus injection of [3H]dextran and [14C]5-HT into the right atrial port of a Swan-Ganz catheter, blood from the radial artery is fractionated and the tritium and carbon-14 of each fraction is measured. The difference between the normalized curves of dextran and 5-HT vs. time reflect the extent to which 5-HT is extracted by the lung. This method gave a mean value of 61 +/- 3% (n = 10) for extraction of 5-HT, compared to 59 +/- 4% measured simultaneously by means of the pulmonary artery-left atrial gradient of 5-HT. Variations among three successive determinations in each patient made postoperatively were not statistically significant. This technique is applicable whenever Swan-Ganz and radial or brachial artery catheters are placed for routine clinical management and, therefore, may have wide application for measurement of pulmonary amine (or kinin) extraction in conscious human subjects or experimental animals. Because pulmonay clearance may be compromised by endothelial damage, 5-HT extraction measured in this manner could reflect early damage to human pulmonary endothelium--perhaps before clinical evidence of damage, such as interstitial edema and respiratory distress, is evident.

Carbon Radioisotopes↗
PubMed1976

5-Hydroxytryptamine extraction by the lung.

Both 5-hydroxytryptamine and norepinephrine are removed from blood during a single passage through the pulmonary vasculature of the dog; 5-hydroxytryptamine is removed to a greater degree than is norepinephrine. The magnitude of extraction of both 5-hydroxytryptamine and norepinephrine is similar to that previously determined in man. In the intact dog, imipramine inhibits the uptake of 5-hydroxytryptamine by the lung in a dose-dependent manner.

Animals↗
PubMed1975

Cardiopulmonary disease in Manson's schistosomiasis.

Five patients with cardiopulmonary manifestations of Manson's schistosomiasis are described. Two patients had pulmonary hypertension, two had cyanosis and one had the very rare combination of both. The results of routine pulmonary function tests--not sufficiently studied in this form of schistosomiasis--are discussed in detail. Aside from a tendency to hyperventilate, found in all cases, the only significant abnormality encountered was hypoxemia due to increased right-to-left shunt in the cyanotic patients. Although more studies are needed, the results suggest that the pulmonary lesions are mainly vascular in nature. The pathogenesis of cyanosis in this disease is briefly discussed.

Adolescent↗
PubMedDate not supplied

Effects of amino acid additives during hemodialysis of children.

The intradialytic losses into the dialysate of free amino acids (AA) and alpha-amino nitrogen were determined during the dialysis of three children. Variations in plasma AA were determined pre- and postdialysis. The effect of these losses with the addition of an Abbott General Amino Acid Mixture to the dialysate in concentrations of 8.5, 17, and 34 mg/100 ml was studied. The major determinant of AA losses was the plasma concentration of the AA before beginning the dialysis treatment. Dialysance of individual AA varied inversely with their molecular weights. A zero flux of alpha-amino nitrogen occurred at a derived concentration of 22 mg/100 ml of the AA additive in the dialysate. Plasma concentrations of nonessential amino acids were little affected by the dialysate additive. In contrast, total essential amino acid nitrogen which fell during baseline dialyses showed significant improvement when the AA solution was added to the dialysate. This study suggests that the addition of AA to the dialysate bath may be effective in decreasing AA nitrogen losses during dialysis.

Adolescent↗
PubMedDate not supplied

Virilising 21-hydroxylase deficiency: timing of newborn screening and confirmatory tests can be crucial.

Early diagnosis of congenital adrenal hyperplasia (CAH) can be lifesaving. With the advent of newborn screening programs employing blood 17-hydroxyprogesterone, fewer cases are missed. Because false positive results occur, especially in premature and low birth weight babies, infants with borderline elevations, although requiring follow-up, are often considered normal. We describe a newborn female that, despite severe virilization, only had a borderline elevation in 17-hydroxyprogesterone (17OHP) on newborn screening, as well as on initial confirmatory testing in our clinical laboratory. Our confirmatory method, which employs high performance liquid chromatography (HPLC) separation, because of its high specificity, yields steroid values from both normal children and those with CAH that are lower than found with older, less specific methods. Given the heterogeneity of phenotypes of CAH, less severe forms, especially in males, could result in marginally abnormal laboratory results early in life, with possible adverse effects later. Although in retrospect the diagnosis of the described patient was clear and not a novel entity, we consider it an important example for several reasons. It emphasizes the broad range of 17OHP levels in CAH, the lack of correlation of these levels with clinical phenotype and the importance of the timing of both screening and confirmatory tests. Due to the complexity of interpreting these tests, any screening program for CAH should be controlled by an experienced pediatric endocrinologist.

Adrenal Hyperplasia, Congenital↗