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Biomedical subjects

D Davis

Publications and source records attributed to D Davis.

At least 307 records · Page 17Linked to original sources

Successful use of oral diazoxide in the treatment of severe toxaemia of pregnancy.

Treatment with oral diazoxide for periods of 4 to 10 weeks in hospital allowed adequate control of hypertension with continuation of fetal growth in four patients with severe toxaemia. Two were insulin-dependent diabetics and one of these suffered from renal failure. In all patients albuminuria diminished markedly, while the fluid retention was controlled with frusemide. Three pregnancies were successfully terminated by lower segment caesarean section and in the remaining case vaginal delivery resulted in the birth of a healthy baby. Control of blood sugars presented no problems in the diabetic patients. Only minimal adjustments of insulin dosage were required. One of the non-diabetic patients developed mild hyperglycaemia which responded to tolbutamide. The babies, ranging in age from 5 to 12 months, have continued to thrive.

Acute Disease↗

Transfer of thymidine kinase to thymidine kinaseless L cells by infection with ultraviolet-irradiated herpes simplex virus.

L cells lacking thymidine kinase (TK) activity (Ltk(-) cells) have been stably transformed to a TK-positive phenotype by infection with ultraviolet-irradiated herpes simplex virus (HSV-UV). The highest frequency of the Ltk(-) to Ltk(+) transformation observed in these experiments was approximately 10(-3), whereas no measurable transformation was observed (less than 10(-8)) in the absence of HSV-UV infection. Cell lines of HSV-transformed Ltk(+) cell lines contain 7 to 24 times as much TK activity as do the parental Ltk(-) cells, and they have been maintained in culture for a period exceeding 8 months. The kinetics of thermal inactivation of the TK activity derived from an Ltk(+) HSV-transformed cell line and the TK activity from Ltk(-) cells lytically infected with infectious HSV are similar. Both of these TK activities are much more thermolabile than the TK activity present in wild-type L cells. A mutant strain of HSV which does not induce TK activity during lytic infection does not cause the Ltk(-) to Ltk(+) transformation. These data suggest that either an HSV TK gene has been transferred to Ltk(-) cells or that an HSV gene product has caused the expression of a previously repressed cellular enzyme.

Animals↗

Determination of iodine concentration and distribution in rat thyroid follicles by electron-probe microanalysis.

The concentration and the distribution of iodine in various sized follicles of rat thyroid glands have been analyzed by electron-probe microanalysis. The results of the iodine analysis were grouped according to uncorrected lumen diameter size. No significant differences in iodine concentration were observed among the various size categories. When the results for all follicles from a given sample were pooled, the standard error of the mean was approximately 4%. Usually 40-50 follicles per animal were analyzed. The concentration of iodine ranged from 0.9 to 2.1% by weight among individual animals. Scanning pictures and step-scan analysis showed the iodine distribution to be quite uniform across the colloid area. Several techniques of sample preparation were used; they produced no significant differences in the iodine concentrations observed. Sodium concentration, also determined in all samples, was found to vary from 2 to 9% by weight. Because of the mobility of the sodium ion, its distribution was greatly affected by the method of sample preparation. The technique that best preserved the natural chemistry of the sample was that of freezing the tissue, sectioning, and then freeze-drying.

Animals↗