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Biomedical subjects

L Siegel

Publications and source records attributed to L Siegel.

At least 37 records · Page 2Linked to original sources
PubMed1984

Total hydrolyzable glycerol in amniotic fluid, and its relationship to fetal lung maturity.

We describe an enzymic quantification of total hydrolyzable glycerol in amniotic fluid. An extract of amniotic fluid is hydrolyzed in mild alkali, without pretreatment with lipase. The resulting glycerol (some of which may be derived from trace amounts of triglyceride) is then enzymatically phosphorylated with adenosine 5'-[gamma 32P]triphosphate to yield glycerol [gamma 32P]phosphate. After removal of excess [gamma 32P]ATP by charcoal, the radioactivity of the glycerophosphate is measured in a liquid scintillation counter. The close correlation (r = 0.96) we found between total hydrolyzable glycerol and phosphatidylglycerol indicates that the contribution of triglyceride to the value for total glycerol is inconsequential. This method is less time consuming and more precise than the method for phosphatidylglycerol.

Amniotic Fluid↗
PubMed1983

An enzymic radiochemical method for determining phosphatidylglycerol in amniotic fluid.

We describe an enzymic quantification of phosphatidylglycerol in amniotic fluid. Phosphatidylglycerol is hydrolyzed in alkali and the resulting glycerol is then enzymatically phosphorylated with adenosine 5'-[gamma-32P]triphosphate to yield glycero[32P]phosphate. After removal of excess [gamma-32P]ATP by charcoal, the radioactivity of the glycerophosphate is measured in a liquid scintillation counter. Triglyceride in the amniotic fluid is hydrolyzed by lipase before extraction and thus does not interfere with the analysis. This method is specific for phosphatidylglycerol. Preliminary studies suggest that a phosphatidylglycerol value greater than or equal to 10 nmol/mL correlates with fetal lung maturity.

Amniotic Fluid↗
PubMed1981

New method for determining lecithin and sphingomyelin in amniotic fluid.

We describe a new method of complete analysis for lecithin, lysolecithin, and sphingomyelin in amniotic fluid. The analysis is based on alkaline hydrolysis of the lecithins and the enzymic hydrolysis of sphingomyelin. The choline formed in each instance is enzymically phosphorylated with [gamma-32P]ATP to yield [gamma-32P]phosphorylcholine, which is isolated by anion-exchange chromatography and shown to be stoichiometrically related to lecithin, lysolecithin, and sphingomyelin. Other phospholipids do not interfere. Using this methodology, we developed three potential approaches to the assessment of fetal lung maturity: the ratio of lecithin plus lysolecithin (total lecithin) to sphingomyelin, the total lecithin concentration, and total lecithin as a percentage of total amniotic fluid phospholipids. All three indices were compared with the lecithin/sphingomyelin ratio obtained by a chromatographic procedure. Our data suggest that measuring the percentage of total lecithin may provide the best means of evaluating fetal lung maturity, but a final judgment must await clinical investigation.

Amniotic Fluid↗
PubMed1978

The emergence of the Bowery as a psychiatric dumping ground.

The drastic reduction of State Hospital population in New York over the past decade has led to a demographic relocation of the mentally ill, rather than any real decline in the rate or severity of mental disorders. Unable to function on their own in society and without adequate supportive facilities available, many discharged patients live in the streets and eventually end up on the Bowery, where they are cared for at The Men's Shelter. Studies have shown that over 50% of the current Bowery population has a history of mental illness and that alcoholism is often a secondary, rather than primary diagnosis. The most frequently encountered diagnostic syndromes are mentioned and commented upon. Possible alternative treatment interventions are suggested.

Age Factors↗
PubMed1978

Free thyroxine in serum as estimated by polyacrylamide gel filtration.

In this new method for estimating free thyroxine concentration in serum by use of polyacrylamide gel filtration, the prolonged incubation that is characteristic of equilibrium dialysis is obviated. Although the values so obtained for the percentage of free thyroxine are severalfold higher than those obtained by dialysis, the results of the two procedures correlate well over a wide range of thyroid states. In addition, the precision of the polyacrylamide method compares well with that for equilibrium dialysis. The method is convenient for use in clinical laboratories and values for free thyroxine in serum of patients with metabolic thyroid disorders are diagnostically discriminatory.

Acrylamides↗
PubMed1978

Estimation of free triiodothyronine in serum: a new method and its clinical relevance.

We describe a method for estimating free triiodothyronine in serum by polyacrylamide gel filtration. Precise and easy to perform, it avoids the lengthy incubation required for equilibrium dialysis. Results of this procedure correlate well with those by the dialysis method over a wide range of thyroid states. The role of free triiodothyronine as part of a protocol for the evaluation of thyroid status is discussed.

Chromatography, Gel↗
PubMed1977

Automated identification of cardiac conduction tissue in L-TGV and Ebstein's anomaly.

The specialized cardiac conduction tissue was identified quickly and easily at operation in 2 patients with corrected transposition (L-TGV) and 1 with Ebstein's anomaly. In each of the former cases the tissue was located along the upper rim of the VSD, beneath the pulmonary outflow tract; in neither patient was there a disturbance in cardiac rhythm as a result of operation. In the patient with Ebstein's anomaly the bundle of His descended onto the ventricular septum more directly than was anticipated. There was only a transitory disturbance in atrioventricular conduction following tricuspid valve replacement. Accurate identification of the cardiac conduction tissue is a prerequisite to the safe repair of certain forms of complex congenital heart disease.

Adolescent↗
PubMed1977

New approach to determination of total ketone bodies in serum.

We describe a one-step assay for total ketone bodies in serum. D-BETA-Hydroxybutyrate is enzymatically oxidized by NAD+ to acetoacetate. This thermodynamically unfavorable reaction is driven to completion by coupling it with the enzymatic reduction of pyruvate by NADH. The acetoacetate so formed, as well as the pre-existing acetoacetate, is quantitatively decarboxylated to acetone in a gas chromatograph and measured directly. Thus by a single measurement for acetone, all three ketone bodies are simultaneously determined. In light of the ubiquity of situations associated with augmented ketone body production, the clinical implications of this approach are extensive.

Acetoacetates↗
PubMed1975

Regional myocardial infarction at operation. An automated system of identification.

The difference between normal and infarcted myocardium at operation cannot always be defected by inspection or palpation. Infarcted myocardium may be identified by a decrease in the amplitude of the ventricular bipolar electrogram. Although this method is reliable and reproducible, it requires a second observer's visual analysis and interpretation of the electrogram signal. This method is therefore subject to the vagaries of human observation, analysis, and accounts of rapidly changing data. We have designed and built an automated instrument to simplify the recognition of transmural infarction.

Animals↗