Biomedical subjects
Publications and source records attributed to K C Gupta.
1. Trimethyl amine oxide, dimethyl amine and choline chloride have been isolated from the marine hydroid Tubularia larynx and identified using physical constants and spectral data. 2. The presence of two guanidine molecules has been demonstrated.
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Tuberculin purified protein derivative (PPD) obtained from the filtrate of Mycobacterium tuberculosis was hydrolysed with proteinase, trypsin, or chymotrypsin. Each hydrolysate consisted of a tuberculin peptides mixture (TPM). From each TPM 16 fractions were obtained by ion-exchange chromatography on Dowex 50W-X8 but only one fraction was isolated from each of the 16 fractions which showed tuberculin activity in guinea pigs sensitized with M. bovis (bcg) or M. tuberculosis. This fraction was designated "purified tuberculin peptide" (PTP). The PTP fraction from the proteinase hydrolysate (PTP-proteinase) was rechromatographed on Dowex 1-X2 and two tuberculin peptide fractions having molecular weights of 3200 and 12,000 were isolated. The potency of these two fractions was assessed in guinea pigs sensitized with M. bovis (BCG) and with M. tuberculosis and they were approximately 4 to 7 times more potent than either the international standaCG and of at least equal potency to either PPD-S or Connaught PPD in guinea pigs sensitized with either M. kansasii, M. scrofulaceum, M. intracellulare, or M. avium whereas very little if any cross-reactivity was elicited by these two fractions. This lack of response indicates that either fraction could be used as an aid to differentiate between sensitization due to M. tuberculosis or M. bovis and sensitization attributed to other mycobacteria.
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Sexual differences in the basioccipital portion of the skull of dogs have been described and an index is presented which reliably predicts the sex of the skull. 92 dolichocephalic skull (44 male, 48 female) from mongrel dogs were used. In the basioccipital region of the male skulls, a triangular area, which extends from the basion to a line joining the medialmost points of the two jugular foramina, appears narrow and elevated. The pharyngeal tubercle is also prominent. In female skulls the rostral angle of this triangle is wider and the triangular area seems smoother and flat. The anterior half of the female basioccipital portion is wider and smoother than in the male skull. In order to quantify the observed differences, four indices were calculated. All of the indices were statistically significant. However, only index IV could be reliably used in predicting the sex of an unknown skull: (formula: see text) was derived from breadth IV (distance between the two temporo-occipital fissures at their lateralmost points) and length II (distance between the basion and a line drawn between the two medialmost points of the jugular foramina in the midline). Values of less than 123 for male and greater than 136 for female placed the skulls in their proper sex group. Skulls that had intermediate values could be placed in correct sex grouping only in conjunction with strong observational criteria. It is suggested that in absence of such strong observational criteria these skulls may belong to immature or castrate animals.
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Some parameters affecting the standardization of a tuberculin preparation have been evaluated and it has been shown that: 1) The loss of tuberculoprotein on the surfaces of containers is in the order of 0.15 mug/cm2 and the 0.18 mug/cm-2 for glass and plastic surfaces respectively, and that this loss can be prevented by the addition of a nonionic anti-adsorption agent such as Tween 80. 2) For non-stabilized tuberculin PPD solutions the losses of PPD due to adsorption increased linearly with the Surface to Volume ration. 3) Exposure to light had a deleterious effect on tuberculin PPD decreasing its biological potency and altering its appearance. This effect increased with the dilution of the tuberculoprotein solution, and can be prevented by storing the tuberculin in amber containers. 4) The potency of tuberculoprotein was dependent on its molecular weight, and the % distribution of tuberculoprotein molecules of different molecular weight varied from batch to batch. This variation can be eliminated by preparing a large batch of tuberculin in a dried form sufficient to fill the demand for many years to come. 5) The route of injection and the species or strains of mycobacteria used for sensitization of guinea pigs affected the relative potency of a tuberculin preparation. 6) The size of a tuberculin skin reaction increased as the volume of tuberculin injected intracutaneously into sensitized guinea pigs was increased although the number of tuberculin units administered was the same. 7) The sizes of skin reactions to certain doses of tuberculin was affected by other doses of tuberculin being injected simultaneously at other sites. 8) Sex and age of guinea pigs affected the size of the tuberculin skin reaction. 9) The genetic make-up of the test animals affected the relative potency of a given tuberculin preparation. 10) Racial differences among various populations might account for different levels of tuberculin reactivity to a given tuberculin preparation. It is hoped that this work has made us aware of the many problems which can be encountered in standardizing tuberculin and it is also to be hoped that the solutions we have offered to some of these problems can be useful to those attempting to standardize allergens other than tuberculin.
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