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Biomedical subjects

S Darling

Publications and source records attributed to S Darling.

27 records · Page 2Linked to original sources
PubMed1977

Plasma renin activity during lithium treatment of patients.

Plasma renin activity (PRA) was determined in patients given lithium treatment. In a longitudinal study PRA was determined in 9 patients before the start of lithium treatment and at intervals during 3 months of treatment. The activity was increased significantly above pretreatment values on day 8 of the treatment; thereafter it fell to pretreatment values. In a transversal study 18 patients given lithium treatment for 2-20 years were compared with 11 control persons. PRA did not differ significantly between the two groups. The results indicate that PRA rises transiently shortly after start of lithium treatment and thereafter falls to pretreatment values where it remains even under prolonged lithium administration.

Adult↗
PubMed1977

Plasma aldosterone and magnesium in serum and urine during lithium treatment.

Serum magnesium, urinary magnesium excretion and plasma aldosterone were determined in 8 manic-depressive before and at intervals during 3 months of lithium treatment (longitudinal study), and in 27 manic-depressive patients who had been treated with lithium for 3 months to 20 years (transversal study). In the longitudinal study urinary magnesium excretion and urine flow increased slightly after 1-3 months of therapy; serum magnesium and plasma aldosterone were unchanged. In the transversal study urinary magnesium excretion, serum magnesium and plasma aldosterone were within normal limits, and they did not differ significantly from levels in the longitudinal study. No correlation was found between serum magnesium or urinary magnesium excretion and plasma aldosterone in either study. The results indicate that changes in urinary magnesium excretion during lithium therapy are not mediated via changes in plasma aldosterone, but may be secondary to diminished renal water reabsorption induced by lithium.

Adult↗
PubMed1977

Plasma renin substrate during lithium treatment.

Inspired from experiments in animals, plasma renin substrate was determined in patients given lithium treatment. In a longitudinal study, renin substrate was determined in 9 patients before the start of lithium treatment and at intervals during 3 months of treatment. In a transversal study, 18 patients on lithium treatment for 2--20 years were compared with 11 control persons. In the longitudinal study, plasma renin substrate values did not, during lithium treatment, deviate significantly from pretreatment values. In the transversal study, values in the lithium-treated patients did not differ significantly from values in the control group. There were no correlations between serum lithium concentrations and plasma renin substrate values. Our study indicates that plasma renin substrate remains unaffected by lithium treatment of manic-depressive patients.

Adult↗
PubMed1977

Parathyroid hormone in serum during lithium therapy.

In ten patients parathyroid hormone, urinary calcium excretion, and fractional tubular reabsorption of calcium were determined at intervals during three months of lithium treatment. Parathyroid hormone increased more than 40% within the first week and remained elevated throughout the treatment period. Calcium excretion fell by more than 30% within the first week and remained low throughout the treatment period. The reduction in urinary calcium excretion could be accounted for by an increase in fractional tubular reabsorption of calcium. There were no significant changes in serum calcium and inorganic phosphate or in urinary inorganic phosphate. The results indicate that lithium treatment affects the hormonal regulation of calcium metabolism.

Adult↗
PubMed1972

Structure and chemical composition of prospheroplast envelopes of Saccharomyces cerevisiae and Hansenula anomala.

Cells of Saccharomyces cerevisiae and Hansenula anomala were digested with snail enzyme under conditions yielding prospheroplasts. Surrounding envelopes were isolated after lysis of prospheroplasts in distilled water. The envelope material was embedded and sectioned for electron microscopy, and thin, hollow structures still retaining the elongated form of the original cells were seen. The envelopes were of low electron density in sections stained with uranyl magnesium acetate and lead citrate, but were more electron-dense when stained with phosphotungstic acid. Shadowed preparations of prospheroplast envelopes revealed structures resembling ghosts. These "ghosts" were similar to the original cells in form and size but seemed to be very thin. Varying numbers of anular structures (bud scars) were found on them. Chemical analyses of the envelope indicated that an alkali-soluble glucan was a major constituent. The results show that the prospheroplast envelope is part of the original cell wall of the yeast and is located in close apposition to the cytoplasmic membrane.

Ascomycota↗
PubMed1969

Kinetic and morphological observations on Saccharomyces cerevisiae during spheroplast formation.

A strain of Saccharomyces cerevisiae which produced elongated cells under our growth conditions was investigated. By digestion of the cell walls with snail enzyme, the cells became spheroplasts after a transient state which we termed "prospheroplast." The prospheroplast could be lysed like the spheroplast, but it retained the shape of the original yeast cell if osmotically protected. Prospheroplasts and spheroplasts were prepared, and thin sections of samples taken throughout the process of wall removal were studied in the electron microscope, at regular intervals up to the time of complete conversion to spheroplasts. In addition, cell wall remnants recovered from spheroplast preparations were shadow cast for electron microscopy. This material revealed structures resembling bud scars with attached membranous matter. The kinetic studies showed that after a certain period of time all cells were transformed into prospheroplasts, whereas spheroplast formation started later, depending on the enzyme concentration. In sections, the prospheroplasts appeared to be formed by detachment of the cell walls. Both the prospheroplasts and the spheroplasts showed asymmetric cytoplasmic membranes in which the outer leaflets appeared coated with a dense fibrillar layer. The experiments suggest that, after enzyme digestion, the cytoplasmic membrane retains a coating which is rigid in the prospheroplast but which loses rigidity when the cell is transformed into a spheroplast.

Animals↗
PubMedDate not supplied

Homologous expressed genes in the human sex chromosome pairing region.

The human sex chromosomes share a pair of homologous genes which independently encode a cell-surface antigen defined by the monoclonal antibody 12E7 (refs 1, 2; see refs 3, 4 for review). The X-located homologue, MIC2X, escapes X-inactivation and the equivalent Y-located locus, MIC2Y, was one of the first genes shown to reside on a mammalian Y chromosome. By using a bacterial expression system we have previously cloned a complementary DNA sequence corresponding to a MIC2 gene and have used this probe to show that the MIC2X and MIC2Y loci are closely related, if not identical. Here we report the use of the cloned probe to confirm the localization of the MIC2X locus to the region Xpter-Xp22.32 (ref. 7) and demonstrate, for the first time, that the MIC2Y locus is located on the short arm of the Y chromosome in the distal region Ypter-Yp11.2. The MIC2 sequences and the sequences described in the accompanying papers by Cooke et al. and Simmler et al. are the first which have been shown to be shared by the sex chromosomes in the pairing region.

Antibodies, Monoclonal↗
PubMedDate not supplied

Inhibition of invasion activity in vitro by a novel class of antitumor agents: silatrane derivatives.

The effect of several silatranes on in vitro invasion of the human amnion basement membrane (BM) by A549 human lung carcinoma cells was examined. Cells treated for two days with the derivatives were examined for invasive activity in the absence of the compounds. From silatrane dose-invasion response curves, an 80% inhibition of invasiveness compared to untreated cells was obtained with 40 micrograms/mg of 1-vinyl silatrane, 50 micrograms/ml of 1-(p-aminophenyl) silatrane, 80 micrograms/mg of 1-(3-phenylthiocarbamidopropyl) silatrane, 66 micrograms/ml of parent silatrane or 171 micrograms/ml of 1-bromosilatrane. Treatment with these doses had no effect on viability, growth or BM attachment of A549 cells.

Antineoplastic Agents↗