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Biomedical subjects

R L Gupta

Publications and source records attributed to R L Gupta.

At least 37 records · Page 2Linked to original sources
PubMed1989

Effect of norharman on the mutagenicity of toluidine metabolites.

Among the different metabolites of o-toluidine only the nitroso and hydroxylamino derivatives were found to be very potent frameshift mutagens in the presence of the co-mutagen norharman and S9. In the absence of norharman and S9 they are only base pair mutagens. Norharman failed to evoke the mutagenicity of the non-carcinogenic m- and p-toluidine and their respective nitroso and hydroxylamino metabolites. This report highlights that norharman plays a role in the appearance of mutagenicity of certain carcinogenic amines and metabolites.

Alkaloids↗
PubMed1986

Mutagenicity of 4-nitrodiphenyl ether and its metabolites.

The mutagenic potential of 4-nitrodiphenyl ether (NDE) an intermediate of herbicides and an anthelmintic drug, and its reduced products (-NO, -NHOH) were investigated in the Ames test. All the three compounds were potent direct-acting base-pair and frameshift mutagens with activity order -NHOH greater than -NO greater than -NO2. The -NHOH compound has been considered to be the penultimate/ultimate mutagen.

Mutagenicity Tests↗
PubMed1985

Structure-mutagenicity relationships within a series of para-alkoxynitrosobenzenes.

The mutagenic potential of para-alkoxynitrosobenzenes (para substituents, -OCH3, -OC2H5, n-OC4H9, n-OC5H11 and n-OC12H25) and p-phenoxynitrosobenzene was investigated in the Ames test. The order of mutagenic activity within a series of p-alkoxynitrosobenzenes was as follows: p-ethoxy greater than p-methoxy greater than p-butoxy (n) greater than p-pentyloxy (n) greater than p-dodecyloxy (n), the last being inactive. A relationship between mutagenic activity and electronic property of different substituents indicated in the alkoxy series, that as the Hammett constant decreased or bulk of the substituent (except methoxy) increased, the activity was found to decrease.

Mutagens↗
PubMed1978

ABO blood groups and serum proteins in thromboangiitis obliterans (Buerger's disease).

In Madhya Pradesh, India, 43 patients with thromboangiitis obliterans showed a decrease in total serum proteins and in the albumin fraction, an increase in a1-and a2-globulin fractions, and decrease in the albumin/globulin ratio. In the ABO blood groups, patients show a significant excess of group B individuals. It is possible that the disease may be more severe in individuals with the B blood group substance.

ABO Blood-Group System↗
PubMed1978

Fluid dynamics of coronary artery stenosis.

A large-scale model of the coronary circulation, instrumented to permit detailed pressure and velocity measurements, has been used to study flow through isolated stenotic elements in large coronary arteries. Pulsatile aortic and instantaneous peripheral resistance were stimulated with servovalves. A variety of axisymmetric and asymmetric stenoses were studied and flow separation was found to occur for all but very mild stenoses. Pressure recovery downstream of the stenosis throat was limited and, in some cases, no recovery was observed. Pressure drop was primarily dependent upon the minimum area of the stenosis and relatively independent of stenosis geometry. Flow was quasi-steady at normal heart rates, and simple steady flow theory proved adequate to describe the pressure drop through the stenosis. The theory yielded results that agreed well with published data for dogs and appears promising for predicting effects of hemodynamic variables on a given stenotic lesion. Thus, principal findings of the study are that a relatively severe stenosis behaves essentially like an orifice and that a simple quasi-steady theory appears adequate to predict effects of a stenosis on coronary flow.

Blood Pressure↗