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Biomedical subjects

S Segal

Publications and source records attributed to S Segal.

At least 595 records · Page 33Linked to original sources
PubMed1976

In situ hybridization of repetitive monkey genome sequences isolated from defective simian virus 40 DNA.

The origin of a repetitive monkey DNA sequence that is incorporated into a defective simian virus 40 genome has been studied. A fragment (about 140 base pairs in length) containing essentially all the repetitive monkey DNA present in the defective and few, if any, SV40 sequences can be cleaved from the purified defective DNA by restriction endonucleases Hind(II and III). Radioactive cRNA prepared with the isolated fragment as template was hybridized in situ to African green monkey chromosomes. The results indicate that all or part of the sequence in question occurs at both centromeric and noncentromeric positions in many, but not all, chromosomes. Of the typical 60 chromosomes, between nine and eleven hybridize with the cRNA in noncentromeric regions.

Base Sequence↗
PubMed1976

Hyperprolactinemic male infertility.

Serum prolactin was studied in 25 fertile and 127 infertile men. The latter included 91 oligospermic, 27 azoospermic, and 9 hypogonadotropic hypogonadal men. The mean prolactin level in all three groups of infertile men was significantly above that of the fertile group. There was no correlation among serum levels of follicle-stimulating hormone, luteinizing hormone, sperm count, and serum prolactin values. Hyperprolactinemia was found in five patients (two oligospermic, one azoospermic, and two hypogonadotropic hypogonadal men). Bromocriptine, 2.5 mg twice daily, suppressed hyperprolactinemia. In one man with hyperprolactinemic oligospermia, treatment with bromocriptine yielded significant improvement in sperm count (to normal values).

Adult↗
PubMed1976

Beta-methylcrotonic aciduria associated with lactic acidosis.

A patient is described in whom lactic acidosis of very severe degree was found to coincide with the presence of beta-methylcrotonic acid and rho-hydroxyphenyllactic acid in urine in large amounts, while beta-hydroxyisovaleric acid was found to be a relatively minor excretion product. Beta-methylcrotonic acid is demonstrated, for the first time, to be present in blood and CSF. These findings are discussed in relation to the patients previously reported to have beta-methylcrotonylglycinuria and raise the possibility that our patient's organic aciduria may be secondary to acquired disease rather than to an inborn error of metabolism.

Amino Acids↗
PubMed1976

Proline and glycine uptake by renal brushborder membrane vesicles.

Uptake of L-proline and glycine by rat renal brushborder membrane vesicles was seen to be osmotically sensitive, pH dependent,and occurred in the absence of proline and glycine metabolism. The uptake system for proline was Na+ gradient dependent, and exhibited a dual system for entry, Km1 = 0.067 mM and Km2 = 5.26 mM. The uptake of glycine was also Na+ gradient dependent, and exhibited a two Km system, Km1 = 0.22 mM and Km2 = 4.00 mM. Studies of proline and glycine interactions indicate a shared site which has a lower affinity and higher capacity for glycine than for proline. The high affinity glycine site and low affinity proline site do not appear to be shared.

Animals↗
PubMed1976

Placental pathology in midtrimester pregnancies interrupted by intra-amniotic injection of hypertonic urea.

The histological appearances of 52 placentae from patients who had a urea-induced second trimester abortion were studied. Extensive subchorionic intervillous fibrin deposition and swollen degenerated stromal cells (probably Hofbauer cells), were found both in the placenta and membranes. Between urea injection and abortion, serial vaginal smears showed signs of progesterone deficiency. The urea-induced placental and fetal damage was similar to that seen with hypertonic saline.

Abortion, Induced↗
PubMed1976

Renal handling of [(14)C]mannose.

The uptake of D-[(14)C]mannose by adult rat kidney cortex slices has been examined. The process involved appeared to be saturable and oxygen dependent and to be inhibited by glucose, galactose, chi-methyl-D-glucoside, and phlorizin. Extensive metabolism of the sugar occurred. (14)CO(2) was produced to an extent comparable to that from D-glucose. Radioactive compounds accumulated in the tissue, approximately 50% of which were in the form of phosphorylated or other polar intermediates. The remaining neutral fraction consisted of mannose with a small amount of label in glucose and an unidentified compound which behaves like an alditol. Mannose concentration in the intracellular fluid was never greater than that of the medium.

Anaerobiosis↗
PubMed1976

Unsaturated fatty acids in adipose tissue of Israeli Jews.

The ratio of polyunsaturated to saturated fatty acids in the adipose tissue of Israelis was found to be 0.88 for Ashkenazic Jews and 1.13 for non-Ashkenazic Jews, the highest reported for any population on a free-choice diet. Despite the unusually high ratios, indicating a high consumption of polyunsaturated fat, there is nevertheless, a relatively high incidence of ischemic heart disease among Israelis.

Adipose Tissue↗
PubMed1975

The ontogeny of antigen-specific T cells.

Although the fetal lamb is unable to form circulating antiovalbumin antibodies until about 120 days of gestation, ovalbumin-specific helper T cells can be stimulated to function at an earlier age. This would suggest that the critical event responsible for the precise sequential maturation of immunologic competence to different antigens at different developmental stages is not the first appearance of specific receptors on immunocytes. Alternative explanations of this phenomenon are discussed.

Animals↗
PubMed1975

Chromatin-positive Klinefelter's syndrome with undetectable peripheral FSH levels.

An 18 year old phenotypic man is described with chromatin-positive Klinefelter's syndrome and undetectable peripheral human follicle stimulating hormone levels. The subject manifested chromosomal mosaicism consisting of three stem cell lines (45X; 46XY; and 47XXY). Testicular biopsy specimen showed germinal cell aplasia: the tubules were lined by Sertoli cells only, whereas the Leydig cells appeared normal. Serum human follicle stimulating hormone levels were undetectable and rose to only 5 mIU/ml after the administration of luteinizing hormone releasing hormone. Serum human luteinizing hormone varied between normal and moderately elevated values, and serum testosterone was in the low normal range. We discuss the features which distinguish this syndrome from isolated gonadotropin deficiency and from classic germinal cell aplasia. We suggest that the patient represents a new variant of Klinefelter's syndrome, with failure of human follicle stimulating hormone release secondary to prolonged hypersecretion.

Adolescent↗
PubMed1975

Prevention of postpartum venous thrombosis with low doses of heparin.

Postpartum superficial and deep venous thrombosis were found in 22.3% and 5.3% of women with varicose veins who delivered vaginally, or by cesarean section. The preventive use of low doses of heparin (5,000 U every 12 h injected subcutaneously) in 116 parturients with varicose veins reduced significantly the incidence of postpartum venous thrombosis. None of the 26 women with previous thrombosis who received preventive treatment, developed such an event.

Dose-Response Relationship, Drug↗
PubMed1975

Prenatal diagnosis of cystinosis.

Cystinosis was diagnosed in a small quantity of cultured amniotic cells from a 22-week-old fetus by a modified pulse-labeling technique in which intracellular 35SL-cystine retention was measured. As a result of the above finding, the pregnancy was terminated by administration of prostaglandin. The diagnosis was confirmed when the nonprotein-free cystine content of the kidney, liver, placenta, spleen, thymus, and gut, as well as that of a large amount of cultured amniotic cells, was found to be 100-fold higher than normal levels.

Abortion, Induced↗
PubMed1975

Developmental aspects of galactose-1-phosphate uridylytransferase in rat intestine.

Kinetic and developmental characteristics of rat jejunal galactose-1-phosphate uridylyltransferase have been examined. Km values for the substrates galactose-1-phosphate and uridine diphosphate (UDP) glucose were the same for both the newborn and adult rat enzymes, although the Vmax of the enzyme in newborns was about threefold higher than that of the adult rat. Equal enzyme activity was present in the villus, crypt cells and the muscularis of adult jejunum. The specific activity of the enzyme remained relatively uniform (V about 20 nmoles/min/mg protein) until 18 days of age when the velocity of the reaction began to decrease. The adult value at 42 days of age is about one fifth of that in the young. The pattern of change of specific activity was compared with that for galactokinase and UDP-galactose-4-epimerase, and the observations suggest separated regulatory factors for each enzyme. The total activity of the galactose-metabolizing enzymes in jejunum was also calculated. In the young, transferase has the highest activity, but in the adult, epimerase activity is highest. Jejunal galactokinase activity is low throughout the developmental period which suggests that phosphorylation of galactose may be the limiting step in intestinal metabolism of the sugar.

Animals↗
PubMed1975

[Esophagoscopy].

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Esophagoscopes↗