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Biomedical subjects

S Segal

Publications and source records attributed to S Segal.

At least 559 records · Page 31Linked to original sources
PubMed1978

Day-to-day variations in serum levels of follicle-stimulating hormone and luteinizing hormone in homosexual males.

Levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone in sera of eight homosexual males and a matched control group were determined every second day during one month. Significant day-to-day variations in serum levels of FSH and a reversed LH area/FSH area ratio among homosexuals were found. There were no significant differences between homosexuals and controls in relation to the average levels of the tested hormones nor the average area and variance of LH and testosterone. It is suggested that a single blood sample for each subject is not enough for hormonal evaluation of homosexuals. It is suggested that the present findings may point to some defect in the gonadotropin regulation in male homosexuals.

Female↗
PubMed1978

Generation of suppressor lymphocytes during sensitization in culture against a syngeneic tumor: affinity chromatography on insolubilized histamine.

We investigated the effect of depletion of histamine-binding lymphoid cells on immunological properties of lymphocytes sensitized in culture against tumor cells. C57BL/6 spleen cells that were sensitized in vitro on monolayers of the syngeneic Lewis lung carcinoma (3LL) became cytotoxic to the tumor cells in vitro after 3 to 5 days of sensitization. Sensitized cells harvested after 4 days of sensitization occasionally enhanced tumor growth in vivo. Fractionation of the sensitized lymphocytes over insolubilized histamine-rabbit serum albumin-Sepharose (HRS) columns decreased or abolished the enhancing activity in vivo and specifically increased the in vitro cytotoxic activity of the depleted lymphocytes. A similar increase in the cytotoxic activity of HRS-fractionated cells was observed in an allogeneic combination of C57BL spleen cells sensitized against C3H fibroblasts. The effect of HRS chromatography on the in vitro cytotoxic activity increased with prolonged incubation of the depleted effector cells with the target cells.

Animals↗
PubMed1978

Human chorionic gonadotropin (beta-subunit) in the early diagnosis of ectopic pregnancy.

In 15 women with suspected ectopic pregnancy considerable amounts of beta-subunit of human chorionic gonadotropin (hCG) were detected in the serum by the radioimmunoassay technique. The diagnosis was proved by laparotomy. In another 25 suspected cases beta-hCG values were less than 1 mU/ml, and in those cases the diagnosis was excluded. The detection of the beta-subunit of hCG in the serum was found to be an excellent tool for the early diagnosis of ectopic pregnancy, thus helping to prevent the dangerous sequelae which follow in the late diagnosis of this condition. The advantage of detecting the beta-subunit of hCG rather than hCG is discussed.

Chorionic Gonadotropin↗
PubMed1978

Size and size distribution of subfertile human spermatozoa.

An improved apparatus for measuring the electrical size (shape factor times volume) of particles based on the Coulter counter principle was used to characterize 110 subfertile semen specimens; size distributions were attainable in the 97 cases with a count above 1 x 10(6) spermatozoa/ml. The typical size distribution was unimodal and positively skewed. Spermatozoa maintained a constant profile during their passage through the orifice of the sizing apparatus, with an effective shape factor of 1.28. Two groups of cells were found. The larger one consisted of 68 specimens with a modal volume of 18.1 +/- 2.0 cu micron and a cell count of 27.5 +/- 9.2 x 10(6) spermatozoa/ml (mean +/- 1 SD). The smaller group contained 29 cases and had a modal volume of 6.6 +/- 0.9 cu micron and a count of 10.2 +/- 7.8 x 10(6). Samples with cell counts below 10 x 10(6) spermatozoa/ml tended to have low modal volumes (less than one-half the normal), but those above showed no particular trend.

Cell Count↗
PubMed1978

Induction of a stable hapten-specific immunosuppression by a hapten conjugated to poly(N-vinylpyrrolidone) (PVP).

The ability of a hapten coupled to a clinically permissive synthetic polymer (NIP-PVP) to induce suppression was investigated. NIP coupled to the low molecular weight non-immunogenic form of poly(N-vinylpyrrolidone) (PVP) was found to be capable of inducing a hapten-specific longlasting suppression of both primary and secondary responses. The previous use of PVP as a plasma expander in humans makes this polymer a potentially suitable tool for the induction of specific immunosuppression to a variety of clinically important drug and tissue specific epitopes. The possible use of low molecular weight PVP for that purpose will be investigated further, specifically with larger antigenic components.

Animals↗
PubMed1977

Enhancing lymphocytes in spleens of tumor-bearing mice: affinity chromatography on insolubilized histamine.

Spleen cells from C57BL mice carrying the metastatic Lewis lung carcinoma (3LL) developed a transient cytotoxic response towards the tumor shortly after tumor transplantation. Later on, the cytotoxic activity was lost and enhancing lymphocytes could be demonstrated in the spleens of the tumor-bearing mice (TBM). Spleen cells that were transferred together with tumor cells into syngeneic recipients enhanced tumor growth. The enhancing activity could be eliminated by the removal of a cell population that bound to histamine/rabbit serum albumin/Sepharose (HRS). The adherent population was enriched for enhancing lymphocytes, since it enhanced tumor growth more than the unfractionated population. The non-adherent cells, on the other hand, lost their enhancing activity in vivo and were sometimes protective against tumor growth. In addition, these cells manifested in vitro cytotoxicity against tumor cells. Hence the suppression of the cytotoxic expression in TBM is, at least in part, due to suppressor lymphocytes that bind to unsolubilized histamine. These cells seem to enhance tumor growth by suppressing host reactivity. Thus the enhancing lymphocyte populations can be separated into two subpopulations, of which one is enriched while the other is depleted of suppressor cells.

Animals↗
PubMed1977

Transport interaction of cystine and dibasic amino acids in renal brush border vesicles.

The uptake of cystine by vesicles prepared from rat kidney brush borders occurs by two distinct transport systems. The higher affinity system is inhibited by the dibasic amino acids lysine, arginine, and ornithine. The lower affinity system, unaffected by dibasic amino acids, appears to correspond to that observed by studying uptake of cystine by kidney slices.

Animals↗
PubMed1977

Activities of acid hydrolases in fibroblasts from normal and cystinotic children.

A study of the lysosomal hydrolases bete-galactosidase, beta-glucuronidase, N-acetyl-beta-D-glucosaminidase, and arylsulphatases A and B has been carried out on fibroblasts cultured from seven patients with cystinosis and eight control subjects. beta-Galactosidase activity was found to be consistently lower in cells derived from cystinotics, while the other enzymes studied showed no significant differences between normals and cystinotics.

Arylsulfatases↗
PubMed1977

From hospital to community care: the change in the mental health treatment system in California.

In 1968 California enacted a law transforming its state hospital centered mental health services to a single system of patient care based on local community responsibility. The 1968 law was not the cause of radical change in California, but rather the culmination of a process that began three decades earlier. The 1963 federal regulation enabling former mental patients to become eligible for categorical aid through public assistance programs and the development of psychoactive drugs were two necessary catalysts that provided the opportunity ot maintain many formerly hospitalized mental patients in the community and to avoid lengthy hospitalization of others.

California↗
PubMed1977

Volume and shape of normal human spermatozoa.

An improved apparatus for measuring the electrical size of particles, developed in this laboratory and based on the principle of the Coulter counter, is used to size human spermatozoa. The typical size distribution is unimodel, with a skew to the right. The actual quantity determined by the measuring system is electrical size (i.e., shape factor X volume); in order to extract the volume, it is necessary to obtain an independence measure of particle shape. This is done by estimating the relative contributions of each part of the spermatozoon, and gives a weighted value for the shape factor of 1.28. The mean value of spermatozoa from 25 normal human seminal fluid specimens is found to be 17.4+/-1.46 cu micronm and the modal volume, 15.2+/-1.27 cu micronm. These values are compared with data reported in the literature after correcting the latter for the effects of particle shape. Zaponin does not affect the cell volume distributions, even when used in high concentrations, provided measurements are carried out within the hour.

Biometry↗
PubMed1977

Phenylalanine-tyrosine deficiency syndrome as a complication of the management of hereditary tyrosinemia.

A male infant with type I hereditary tyrosinemia developed a phenylalanine-tyrosine deficiency syndrome after receiving a synthetic diet which was low in these amino acids. The syndrome was characterized by growth failure, anorexia, lethargy, and hypotonia. Hypophenylalaninemia and hypotyrosinemia were discovered. The blood concentration of most other amino acids were increased. Supplementation of the patient's diet with phenylalanine and tyrosine resulted in a prompt and dramatic reversal of both clinical and biochemical abnormalities. Dietary therapy had no effect on the child's hepatic cirrhosis.

Amino Acid Metabolism, Inborn Errors↗
PubMed1977

Ontogeny of glycine transport in isolated rat renal tubules.

Isolated renal tubule preparations were made from newborn Sprague-Dawley rats and used to study initial entry rate kinetics of glycine. The results were compared to those obtained in the isolated tubule preparation from the adult rat kidney. While initial rates of glycine uptake were identical for newborn and adult tubules, significant differences in influx kinetics were demonstrated. Of the two apparent transport Km systems shown to be present in the newborn tubule, the high-affinity, low-capacity system accounts for about 40% of total glycine uptake at physiologic concentrations. The high-affinity, low-capacity system of the adult tissue accounts for about 10% of total uptake at the same concentration range. The data lend strength to the argument against the concept that the physiologic hyperglycinuria of the newborn rat is due to either impaired ability to concentrate glycine intracellularly or to absence of one or more transport mechanisms for glycine.

Animals↗