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Biomedical subjects

S M Shaw

Publications and source records attributed to S M Shaw.

At least 55 records · Page 3Linked to original sources
PubMed1978

Fetal effects of cadmium in pregnant rats on normal and zinc deficient diets.

This investigation has shown that not only the extent of fetal resoprtion and malformation but also the types of malformation seen in rats depend upon the strain used and day of gestation. Furthermore, the effects of zinc deficiency and cadmium administration on the fetus can be at least additive, as was seen for malformations. For fetal resorption, zinc deficiency potentiated the action of cadmium.

Abnormalities, Drug-Induced↗
PubMed1978

The maternal distribution and placental transfer of cadmium in zinc deficient rats.

Although a transitory maternal zinc deficiency has been shown to result in an increased cadmium-induced fetotoxicity, the results of the present investigation indicated that a maternal zinc deficiency apparently did not affect the placental transfer of cadmium. However, a zinc deficiency did alter the maternal distribution of cadmium. The increased cadmium fetotoxicity associated with a maternal zinc deficiency may be caused by a maternal alteration rather than a direct effect on the fetus. Further study is necessary prior to any definitive statement concerning the effects of a maternal zinc deficiency on cadmium fetotoxicity.

Animals↗
PubMed1977

Absorption, distribution, and excretion of 14C-meglumine in rats and dogs after administration of 14C-meglumine salicylate.

Meglumine labeled with carbon-14 was administered orally as 14C-meglumine salicylate to rats and dogs to study its distribution and excretion. The compound was incompletely absorbed; that which was absorbed was rapidly excreted in the urine. Peak blood levels were about 5-10 mug/ml in rats and 2-8 mug/ml in dogs. Tissue levels were negligible at the end of the experimental periods. No evidence for N-demethylation or oxidation to carbon dioxide was obtained.

Animals↗
PubMed1977

Use of microcapsules as timed-release parenteral dosage form: application as radiopharmaceutical imaging agent.

The development of a new type of parenteral dosage form is described. A system of microencapsulation was formulated which produced microcapsules containing a water-soluble core material. The basic microencapsulation system could be altered to produce microcapsules with varied timed-release characteristics. Tracer methodology was employed as a sensitive and versatile analytical tool for the development and evaluation of the microencapsulation system. The core material was labeled by neutron activation after microcapsule formulation, which eliminated the radiation hazard and contamination problems that could occur during formulation with a labeled core material. Both in vitro and in vivo testing showed that the release patterns of labeled core material could be altered and detected. The microcapsules developed have potential as a timed-release parenteral dosage form and as an organ-imaging radiopharmaceutical.

Animals↗
PubMed1977

Synthesis of 14C-meglumine salicylate and its disposition in humans after oral administration.

The synthesis of 14C-meglumine salicylate was accomplished by heating 14C-meglumine with salicylic acid, in equimolar ratios, in 2-propanol. The average radiochemical yield was 97.5%. Ten healthy adult male volunteers were given 1.2 g of the compound orally. Five took 1.2 g of 1-deoxy-1-[14C]-methylamino-D-glucitol salicylate (containing about 47 micronCi), and five others took 1.2 g of 1-deoxy-1-methylamino-D-[U-14 micronCi), and five others took 1.2 g of 1-deoxy-1-methylamino-D-[U-14C]-glucitol salicylate (containing about 45 micronCi). Urine and feces were collected for 5 days, and blood was sampled for 24 hr. The peak urinary excretion of meglumine and/or its metabolites occurred between 4 and 8 hr after administration (about 7.2% of the administered dose). Meglumine was excreted primarily in the feces (72.4% over 5 days) and, to a smaller extent, in urine (21.3% over 5 days). No activity was detected in blood. The excretion rate and percentage excreted were the same for both groups of subjects, suggesting that meglumine was not metabolized by N-demethylation or conversion to carbon dioxide. The highest blood salicylate level, 44.4 +/- 1.9 microng/ml, was observed 1 hr after administration. Urinary levels of salicylic acid and its metabolites were observed to be at a maximum at 8 hr. Total salicylate recovery was 94.7 +/- 1.5% in 48 hr. Salicyluric acid was the major metabolite, accounting for 69.5 +/- 3.6% of the dose. Salicylic acid accounted for 6.8 +/- 1.2%.

Administration, Oral↗
PubMed1976

Need for supervision in the elderly receiving long-term prescribed medication.

Medication for 127 randomly selected patients aged over 70 in a large group practice was examined in relation to the available supervision for this treatment. About half the patients were on long-term treatment, mainly drugs associated with heart disease, depression, or anxiety. Nineteen had had no recorded contact with the family doctor for six months or longer, and examination by nurse surveillance suggested that three might be suffering from drug toxicity. It was concluded that reliance on self-referral by elderly patients was unsafe.

Aged↗
PubMed1975

Placental transfer and teratology of pentachlorophenol in rats.

Pentachloro[U-14C]phenol was administered orally to Charles River CD strain pregnant rats on day 15 of gestation. Concentrations found in the placentas and fetuses up to 32 hr remained very small indicating that the amount that passes through the placental barrier is negligible. Unlabeled compound was administered on days 8, 9, 10, 11, 12, and 13 of gestation. The incidence of resorptions in the treated animals was not significantly greater than that in the controls. Although malformations were observed, the number was minimal and could have been due to the toxic effects of the compound on the maternal rat.

Abnormalities, Drug-Induced↗
PubMed1975

Improved colorimetric determination of salicylic acid and its metabolites in urine.

We describe an improvement in the Levy and Procknal method [J. Pharm. Sci. 57, 1330 (1968)] for determination of salicylic acid and its metabolites in urine. Salicylic acid and salicyluric acid are successively extracted from 1 or 2 ml of urine (acidified with HCl) by two 10-ml portions each of carbon tetrachloride and ethylene dichloride. The extracts of each solvent are shaken with 5 ml of ferric nitrate solution (a 10-fold dilution of 17 g of Fe(NO-3)-9H-2O in 1 liter of 70 mmol/liter HNO-3). The aqueous phases are centrifuged and their absorbances measured at 530 nm. For total salicylate, 3 ml of urine and 3 ml of HCl are heated in a partially evacuated serum vial at 100 degrees C for 16 h and then salicylic acid is assayed in the hydrolyzed sample. Recovery of a weighed oral dose of sodium salicylate in urine was 105.4%; it was 127.9% by the Levy and Procknal method for the same sample. The improved method is faster and more accurate.

Colorimetry↗