A gas chromatographic method is described for acrylonitrile monometer (AN), using a nitrogen/phosphorus detector. Procedure for the analysis of AN in 5 food simulants (water, 3% acetic acid, heptane, 50% ethanol, and 8% ethanol) as well as in the polymer matrix are included. The quantitation limit for direct injection of AN/food simulant solution is 0.04 ng AN/microliter. AN-based polymers are dissolved in N,N-dimethylacetamide and injected directly. Residual AN in the polymer can be quantitated at the 0.5 ng/microliter level. Results of migration studies are also presented.

Acrylonitrile↗

PubMed1977

An analytical approach to the quantitation of known drugs in human biological samples by HPLC.

Although many HPLC methods are available in the literature only a fraction of these are applicable to the analysis of known drugs in human biological fluids. This paper presents the favoured approach of a laboratory involved in the quantitative assay of drugs in man for the subsequent study of pharmacokinetics and bioavailability.

Allopurinol↗

PubMed1977

The effect of tolbutamide on contractility and cyclic adenosine 3':5'-monophosphate concentration in the intact beating rat heart.

The effect of tolbutamide on contractility and the concentration of cyclic adenosine 3':5'-monophosphate (cyclic AMP) in ventricular muscle was examined in the intact beating rat heart. The hearts were perfused in a nonrecirculated (Langendorff) fashion. Bolus injections of tolbutamide caused an increase in cardiac contractility. This increase in contractility was markedly inhibited when bovine albumin (3 g/100 ml) was present in the perfusing fluid. The increase in contractility caused by tolbutamide was not preceded by or associated with any change in the concentration of cyclic AMP in the ventricular muscle. Further studies utilizing a simultaneous injection of norepinephrine and tolbutamide demonstrated no significant effect of this combination on the concentration of cardiac cylcic AMP produced by an injection of norepinephrine alone. Our findings suggest that in the intact beating rat heart the positive inotropic effect of tolbutamide is not mediated via an increase in the concentration of cardiac cyclic AMP and that tolbutamide does not significantly potentiate the effect of catecholamines on cardiac cyclic AMP concentration.

Albumins↗

PubMed1977

Gas-liquid chromatographic headspace technique for determination of vinyl chloride in corn oil and three food-simulating solvents.

A gas-liquid chromatographic headspace technique for the determination of vinyl chloride (VC) in corn oil, 50% ethanol, 3% acetic acid, and n-heptane is described. These food-simulating solvents and the corn oil are placed in septum-sealed bottles and heated to 90 degrees C, and aliquots of headspace vapor are injected into a gas-liquid chromatograph equipped with a flame ionization detector. VC may be quantitated at concentrations of 1 ppb or less. This technique was used to measure the migration of VC into corn oil and 50% ethanol from 2 unplasticized polyvinyl chloride sheets containing 0.28 and 0.44 ppm residual monomer.

Chromatography, Gas↗

PubMed1977

Experimental toxoplasmosis in calves.

Nine calves were inoculated with tissue cysts of a low virulence strain of Toxoplasma gondii and killed at intervals up to 10 weeks. An immunological response took the form of circulating antibodies and reactive changes in the lymph nodes. The organism could only be recovered from the lymph nodes and this only during the first four weeks after infection. No tissue cysts were demonstrated and only a few inflammatory lesions occurred. Thus, although calves can be infected, the immunological response is prompt with rapid elimination of the organism.

Animals↗

PubMed1976

Blood volume changes and production and destruction of erythrocytes in newborn dogs.

Erythrocyte, plasma, and total blood volumes were measured in dogs from birth to maturity. All of these volumes (per kilogram of body weight) were significantly greater in the dog at birth than at maturity. Erythrocyte volume decreased during neonatal and postnatal periods to less than that during adult period. Erythrocyte production and destruction were measured with a technique combining dilution method of T-1824 for blood volume measurement with uniform tagging of newly formed erythrocytes with 29Fe. Erythrocyte destruction was high during the first 2 weeks after birth.

Age Factors↗

PubMed1975

Gas-liquid chromatographic determination of vinyl chloride in vinyl chloride polymers, food-simulating solvents, and other samples.

The determination of vinyl chloride (VC) in polyvinyl chloride (PVC), vegetable oils, food-simulating solvents, mouthwashes, and blood anticoagulant solutions by gas-liquid chromatography is described. PVC polymers are disolved in either tetrahydrofuran or dimethyl acetamide. Vegetable oils are diluted with an equal volume of tetrahydrofuran. The resulting solutions are injected into a gas-liquid chromatograph equipped with a flame ionization detector. Mouthwashes, blood anticoagulant solutions, and 3 food-simulating solvents, 3% acetic acid, 50% ethanol, and heptane, are analyzed by direct injection into a chromatograph. Sensitivities are such that 0.05 ppm VC in solution or 1 ppm VC in PVC can be quantitated.

Anticoagulants↗

PubMed1974