Search PubMed⌕ Search

Biomedical subjects

S Lieberman

Publications and source records attributed to S Lieberman.

At least 73 records · Page 4Linked to original sources
PubMed1981

Human kidney preservation by intracellular electrolyte flush followed by cold storage for over 24 hours.

Many transplant teams are reluctant to accept kidneys preserved with intracellular electrolyte flushing followed by simple cold storage when preservation time exceeds 24 hr. This study from one center is a comparison of 63 primary cadaver kidney grafts preserved with Collins 2 solution flush followed by cold storage for 9 to 23 1/2 hr to 42 primary cadaver kidney grafts preserved by the same method for 24 to 44 1/2 hr. Kidneys cold-stored for over 24 hr had a significantly increased requirement for dialysis in the first week following transplantation (55% versus 30%). One-month serum creatinine nadirs and actuarial graft survivals were not significantly different. Cadaver donor methylprednisolone (30 to 60 mg/kg) 2 to 9 hr prior to kidney removal reduced the requirement for first-week hemodialysis in the kidneys cold-stored for over 24 hr (23% versus 69%, P under 0.05). A human kidney preserved by the same method and cold-stored for 61 hr was successfully transplanted into a 38-year-old myelodysplastic. Satisfactory human kidney preservation can occur with intracellular electrolyte flush solutions followed by cold storage for over 24 hr when the warm ischemia time is very short.

Cold Temperature↗
PubMed1981

Measurement of bile acid production in hyperlipidemic man: does phenotype or methodology make the difference?

Bile acid production has been measured in 13 studies in 10 hyperlipidemic subjects by simultaneous use of isotope dilution kinetics and chemical balance methodology. When the data of all 13 studies were averaged, the correlation between the two sets of values was negative and weak (r - 0.01, NS). However, when the correlations for normoglyceridemic and hyperglyceridemic subjects were examined separately, a strong positive correlation was found between the values obtained by the two methods in normoglyceridemic subjects (r + 0.92, P less than 0.01) but not in hyperglyceridemic subjects (r - 0.25, NS). Examination of bile acid specific activity decay characteristics in eight studies, where bile was sampled up to six times within the first 24 hr after radio-labeled bile acid infusion, revealed differences in three rate of attainment of peak specific activity and in the time taken subsequently to achieve first order kinetic decay. However, analysis of the data from these eight studies by input-output analysis yielded values for primary bile acid synthesis no different that those generated by conventional isotope dilution kinetics. Thus, bile acid production in normoglyceridemic subjects may be accurately quantitated by either isotope dilution or chemical balance methodology. Our data, as well as results from other laboratories, indicate that the values obtained are strictly comparable. On the other hand, the quantitation of bile acid production in hyperglyceridemic subjects by isotope dilution kinetics gives higher values than those obtained by chemical balance methodology, and in addition, higher values than those obtained in patients with normal plasma triglyceride levels.

Adult↗
PubMed1980

Identification of fatty acid esters of pregnenolone and allopregnanolone from bovine corpora lutea.

The lipoidal derivatives of steroids present in bovine corpora lutea have been identified and quantified. Nonpolar steroid derivatives were extracted from the tissue with a mixture of chloroform and methanol. The extract was subjected to column and high performance liquid chromatography in order to remove phospholipids, cholesterol, triglycerides, cholesteryl esters, and unesterified steroids. A portion of the purified nonpolar material was subjected to methanolysis. By gas-liquid chromatographic analysis, the products were shown to consist of the steroids 3 beta-hydroxy-5 alpha-pregnan-20-one (80%) and pregnenolone (20%), and the methyl esters of palmitic (34%), stearic (27%), oleic (22%), linoleic (7%), arachidonic (7%), palmitoleic (3%), and eicosatrienoic (1%) acids. Mass spectrometric analysis of the intact lipoidal derivatives and of their methoximes confirmed the presence of seven esters of allopregnanolone and pregnenolone: allopregnanolone palmitate, pregnenolone palmitate, allopregnanolone stearate, allopregnanolone oleate, allopregnanolone linoleate, allopregnanolone eicosatrienoate, and pregnenolone arachidonate. The mass spectral data suggested that four other esters were also present: pregnenolone stearate, pregnenolone oleate, pregnenolone linoleate, and allopregnanolone arachidonate.

Animals↗
PubMed1980

The lipoidal derivatives of steroids as biosynthetic intermediates.

The lipoidal derivatives of [3H]pregnenolone, prepared biosynthetically, were converted, by incubation with a mitochondrial-microsomal fraction from adrenal cortical tissue, into lipoidal derivatives of 17-hydroxy-pregnenolone and of dehydroisoandrosterone, thus proving that these pregnenolone derivatives can serve as substrates for 17-hydroxylase and for the lyase enzyme that converts a C21-17-hydroxy-20-ketol into a C19-17-ketosteroid. Three synthetically prepared esters of pregnenolone, the oleate, the linoleate, and the arachidonate, were also hydroxylated at C-17 by a similar adrenal preparation. With the synthetic substrates, however, the corresponding esters of dehydroisoandrosterone were not formed.

Adrenal Glands↗
PubMed1980

C19 steroidal precursors of estrogens.

The pathways of biosynthesis of the estrogens from C19 steroids has been examined by in vitro kinetic experiments using human placental microsomes and two precursors, each labeled with a different radioisotope. The results indicate that under the conditions employed, androstenedione is an obligatory intermediate in the conversion of 3 beta-hydroxy-5-androsten-17-one (dehydroisoandrosterone) or its sulfate, dehydroisoandrosterone sulfate, into estrone and estradiol. The same result was obtained when the microsomal fraction was replaced by either a 1000 x g supernatant preparation from human placenta or a homogenate of placental mitochondria. If alternative pathways involving C19-hydroxylated derivatives of dehydroisoandrosterone or its sulfate exist, they appear to be of minor quantitative significance.

Androstenedione↗
PubMed1979

Characterization of the lipoidal derivatives of pregnenolone prepared by incubation of the steroid with adrenal mitochondria.

Using mass spectrometric, radioisotopic, chromatographic and chemical techniques, five fatty acid esters of 3 beta-hydroxy-5-pregnen-20-one (pregnenolone) have been identified as components of the lipoidal derivatives biosynthesized in vitro with bovine adrenal mitochondria. The five compounds are: pregnenolone arachidonate, pregnenolone linoleate, pregnenolone oleate, pregnenolone palmitate, and pregnenolone stearate. The distribution of the fatty acids among these five esters is different from the previously reported (Cmelik, S.H.W., and Ley, H. (1977) Comp. Biochem. Physiol. 56B, 267-270) fatty acid composition of these organelles.

Adrenal Cortex↗
PubMed1979

Side chain cleavage of some cholesterol esters.

For some time it has been known that the side chain of cholesterol sulfate is cleaved by the cleavage enzyme system present in bovine adrenal mitochondria without prior hydrolysis of the sulfate moiety. In this work, other inorganic esters as well as some organic esters of cholesterol were tested as substrates for this enzyme system. The results revealed that cholesterol nitrate, cholesterol phosphate, and a series of acyl esters of cholesterol can also be cleaved by the enzyme system to their respective pregnenolone derivatives without first being hydrolyzed to cholesterol. The rate of oxidation of the carboxylic acid esters decreased as the size of the acyl groups increased. Cholesterol stearate and cholesterol phosphate were demonstrated to be inhibitors of the side chain cleavage of cholesterol. While digitonin, as might be expected, inhibits the cleavage of cholesterol, it accelerates the oxidation of both cholesterol sulfate and cholesterol nitrate. The results reported in this paper add support to the previously proposed hypothesis that more than one cholesterol side chain cleavage enzyme system exists in adrenal mitochondria.

Adrenal Glands↗
PubMed1979

The activation of microsomal steroid 21-hydroxylase by cytosol from the cortex of bovine adrenals.

At low microsome concentrations, the addition of cytosol from bovine adrenal cortex markedly accelerates the rate of hydroxylation of 17-hydroxyprogesterone at C-21. The detection of this effect was made possible by the development of a new, rapid, and sensitive procedure for the measurement of the initial rate kinetics of steroid 21-hydroxylase. This procedure is based on the fact that the reactant, 17-hydroxyprogesterone, possesses solvent partition properties which are different from those of the product, cortexolone. The specificity of the assay was confirmed by the isolation of only one product which was identified as cortexolone by radiochemical techniques. This assay procedure has great sensitivity and makes possible the accurate determination of the Michaelis constant at low enzyme concentrations. The Km for 17-hydroxyprogesterone with saturating amounts of TPNH was found to be 0.3 micronM. At the low microsome concentrations permitted by this assay, the addition of cytosol has a profound effect upon the rate of hydroxylation. The rate is markedly accelerated although the Km for the substrate is not altered. Neither the substrate nor the carbon monoxide-induced difference spectra are changed by the addition of cytosol, suggesting that activation by cytosol dose not affect the catalytic unit of the 21-hydroxylase complex.

Adrenal Cortex↗
PubMed1978

Nineteen cases of morbid grief.

Three different patterns of morbid grief are noted. The effect of forced mourning procedures on morbidly grieving patients is discussed with some indication of beneficial and harmful effects of psychotherapeutic intervention.

Adult↗
PubMed1978

Teaching psychotherapy in mental hospitals.

This paper deals with the early results and problems of establishing and developing a regional training programme in psychotherapy, using peripatetic senior lecturers. The difficulties of a psycho-analytic approach to psychotherapy in mental hospitals are discussed, and a model of psychotherapy more suitable for general application in mental hospitals and district general hospital psychiatric units is proposed.

Education, Medical, Graduate↗
PubMed1978

Comparative educational approaches to screening for colorectal cancer.

The purpose of the study was to evaluate the public's willingness to perform the do-it-yourself Hemoccult Test for colon-rectum cancer and to assess the relative effectiveness of alternative means of persuading people to do the test. American Cancer Society volunteers in four different part of the country contacted a total of 11,115 members of the American Association of Retired Persons, using five methods that differed in the extent of personal and impersonal contact involved. Other variables such as inclusion of postage and dietary restrictions were studied and cost efficiencies were estimated. The Group Meeting Method was the most effective personal distribution method. The Selective Mail-Out Method was the most effective impersonal method. The return rate was higher when postage was provided. Dietary restrictions did not markedly reduce participation. Including digital examinations did not affect the return rate. The findings suggest that the Hemoccult Test has the potential of reaching a significant proportion of the nation's older population.

Colonic Neoplasms↗
PubMed1978

Comparison of cholesterol turnover by sterol balance and input-output analysis, and a shortened way to estimate total exchangeable mass of cholesterol by the combination of the two methods.

Daily turnover of cholesterol obtained by the balance method was compared to daily input rates calculated by input-output analysis in 43 experiments. The mean value of input rates for kinetic data of 10.1-16.4 weeks' duration (14 experiments) was 1.05 g/day vs. the chemical turnover of 0.94 g/day (difference 10.9 percent). For decay curves of 4.8-9.9 weeks' duration (29 experiments) the mean results were 1.67 g/day vs. 1.31 g/day, respectively (difference 20.1 percent). A combination of the balance method with input-output analysis is proposed to estimate the size of M (minimum value of the total exchangeable mass of cholesterol) in short-term experiments. Using this method, the analysis of curves of 10-12 weeks' duration showed a mean difference of 7.5 percent with the analysis of curves of 50-66 weeks' duration in 17 patients. However, because of considerable variations that can occur in individual cases, it is urged that a standard correction factor not be used, either in estimating turnover data or M from 10-12 weeks' kinetic data; rather, the proposed combined method will alert the investigator to the occurrence of discrepant results.

Adult↗