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Biomedical subjects

M Mathur

Publications and source records attributed to M Mathur.

At least 163 records · Page 9Linked to original sources
PubMed1981

Dynamic responses to continuous use of prazosin and hydralazine in patients with refractory heart failure.

The hemodynamic effects of oral doses of prazosin and hydralazine were studied in the same group of patients with chronic congestive heart failure. Prazosin, 3 to 10 mg, and hydralazine, 75 to 100 mg, were given by mouth every 6 hr and the responses to the first and the fifth consecutive dose were compared. The first dose of prazosin was followed by a predominant effect of left ventricular filling pressure and concomitantly by reduction of left ventricular afterload. Hydralazine acted primarily on left ventricular afterload with no significant effect on the filling pressure. A marked difference was noted in respect to the dynamic responses to continuous therapy with these two drugs. While the initial hemodynamic effect of prazosin was markedly attenuated in most of the cases after the fifth consecutive oral dose, the response to hydralazine was augmented by continuous therapy. These findings suggest that the reported hemodynamic tachyphylaxis seen with prazosin does not occur with hydralazine when given to the same patients with chronic congestive heart failure. Our study also indicates the importance of prolonged monitoring for the assessment of the hemodynamic effect of prazosin and hydralazine in patients with severe chronic congestive heart failure.

Aged↗
PubMed1981

Aflatoxin B1-induced injury in monkeys.

Short-term effects of small doses of aflatoxin (0.05 mg/kg of body weight twice a week) were studied in rhesus monkeys fed low-protein and high-protein diets. Animals on high- and low-protein diets without aflatoxin administration served as controls. There was no difference in weight gain, hemogram, serum protein levels, and liver function test results between aflatoxin-treated and control animals. However, morphological alterations in hepatocytes in the form of mild degenerative changes, focal areas of necrosis, and increased regenerative activity were seen in the aflatoxin-treated monkeys. Data on cell cycle analysis done by DNA content estimation through microfluorimetry on DNA-fluorescent, acriflavin-stained liver imprints revealed larger number of cells in the S and Gi2 phases in animals given aflatoxin. However, the changes in cell cycle, as well as in morphology, were more marked in the aflatoxin-treated, low-protein-diet group.

Aflatoxins↗
PubMed1976

Kinetics of proliferation and differentiation in the hair follicle and epidermis in neonatally undernourished rats.

Cell population growth kinetics of hair follicle and epidermis were measured in rats undernourished during suckling by increasing the litter size. Animals reared in litters of normal size served as controls. There was a marked atrophy of epidermis and hair follicles, and the thickness and length of the hairs were markedly reduced in the undernourished animals. Autoradiography following pulse labeling with 3H TdR demonstrated prolongation of the cell generation cycle. The G2 and S phases were chiefly affected, whereas the G1 was not altered. The double pulse labeling technique indicated a hold-up in the S phase in the epidermis, although the labeling index was not altered in the undernourished rats. On the basis of available literature, it is porposed that G2 is more energy dependent, whereas protein deficiency affects predominantly the S phase. Unlike the alteration in cell generation cycle, the process of differentiation--measured histochemically and on the basis of rate of migration of 3H-TdR-labeled bulb cells--appeared to be unaffected in undernutrition. However, there was a lag in the movement of cells out of the germinative zone. It is proposed that in undernutrition, cells spend longer time in the germinative zone to complete a critical number of division which may be peculiar to every tissue.

Animals↗
PubMed1976

Measurement of cardiac output by thermodilution in infants and children after open-heart operations.

Five hundred twenty-five measurements of cardiac output were made in 26 infants and children after primary repair of congenital cardiac defects. The Edwards Model 9500 thermodilution output computer was used. Cold indicator was injected into the right atrium; in 405 measurements the signal was sensed in pulmonary artery (PA) and in 120 in left atrium. One hundred seven measurements of output by dye dilution (DD) were made in 9 of the infants. Reproducibility was only slightly less good for thermodilution (ID) with PA sensing than for DD but was considerably worse with left atrial sensing. Outputs measured by TD agreed well with those by DD (r = 0.9065). Precautions necessary for accurate measurements and the advantages of TD in infants are discussed.

Body Temperature↗
PubMed1976

Kinetics of mobilization of neutrophils and their marrow pool in protein-calorie deficiency.

Migration of marrow neutrophils under basal conditions and their mobilization, following subcutaneous implantation of cover slips, were investigated in groups of protein-deficient rats, using 3HTdR with sequential autoradiography of the peripheral blood smears. Animals fed a protein-rich diet served as controls. The pattern of appearance of labeled neutrophils in the blood was identical in the two groups under basal conditions. However, a higher percentag of labeled neutrophils appeared earlier in the blood following cover slip implantation in the deficient rats as compared to controls. The inflammatory exudate on the cover slips was low throughout the period of observation in deficient animals, with a delay in the appearance of monocytes. A pool of mature neutrophils resides in the bone marrow. It is proposed that in PCM there is atrophy of all neutrophil compartments, including that of the marrow pool, associated with a proportionate reduction in the efflux of cells from one compartment to another. This proportionate reduction in efflux would explain the normal kinetics of migration of neutrophils under basal conditions in the deficient rats in spite of a reduction in the marrow pool. On the other hand, in cover slip-implanted deficient rats, appearance of larger numbers of labeled neutrophils in the blood is attributed to a reduction in size of the marrow pool. This hypothesis is substantiated by the experiments in protein-deficient monkeys in which estimation of the marrow pool of neutrophils revealed a marked reduction in the deficient animals. It is further proposed that a diminuation of the marrow pool of neutrophils and retarded mobilization of cells at the site of inflammation are important mechanism responsible for the increased susceptibility of the malnourished host to infections.

Animals↗