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Biomedical subjects

B Iyengar

Publications and source records attributed to B Iyengar.

At least 55 records · Page 3Linked to original sources
PubMed1983

Variations in clinical and histopathological classification of leprosy--a report and a plausible explanation.

Biopsies of macular hypopigmented lesions, in twenty one untreated cases, representing the whole spectrum of leprosy, revealed a high incidence of disagreement between clinical and histopathological classification. It was not observed in macular tuberculoid and indeterminate cases but was seen in borderline and lepromatous leprosy, with highest incidence in borderline leprosy. This has been explained on the basis of complex nervous system with a mosaic of anatomical and physiological subunits, modulating different types of responses including inflammation, through release of peptides and/or enzymes at the nerve endings in the peripheral tissues including skin.

Humans↗
PubMed1983

A study of clinico-histologic correlation in lesions of borderline leprosy with multiple skin biopsies from different sites.

20 active untreated cases of borderline leprosy were subdivided on clinical, bacteriological and immunological grounds. None had reactional episodes. Multiple skin biopsies from each one of them showed varied histopathology from different lesions. 84 out of 93 biopsies (90.3%) were found not to be in agreement with the clinical diagnosis. Even the multiple biopsies obtained from single large lesion revealed varied histopathological picture. The reason for the histopathological disparity has been postulated.

Adolescent↗
PubMed1982

The germ cell - oncogenic and embryogenic correlates.

This study is based on 100 consecutive germ cell tumors of the gonads, received during a 5-year period. Benign teratomas, with totipotent differentiation are the commonest ovarian germ cell tumors, whereas the nullipotent germinomas from the bulk of the testicular tumors. Differentiation in the rapidly proliferating testicular teratomas, occurs in the form of embryoid bodies and organoid structures. From an analysis of the germ cell tumors it is evident that the ovum confers differentiating functions on the zygote, while the spermatozoon confers functions of organization and proliferation. This difference in the behavior of the 2 germ cells is due to local feedbacks within the cortical and medullary zones of the gonads.

Cell Differentiation↗
PubMed1982

Effect of the active tumor promoter, 12-O-tetradecanoylphorbol-13-acetate on hair follicular growth and development of hair anlage tumors in the mouse skin: a comparison with human adnexal lesions.

Effect of the active tumor promoter, TPA, on the induction of hair follicular growth and possible neoplasia was studied histologically in normal nd precancerous mouse skin. Biweekly application of TPA resulted in nevoid proliferation of hair follicles, decreased the latent period of tumor induction, and increased the number of carcinomas of hair follicular origin in mice pretreated with MCA. The experimental tumor induction data was compared with human adnexal tumors of hair follicular origin. Similar types of animal and human lesions could be attributed to the promoter effect alone or to the dual influence of a carcinogen and promoter.

Animals↗
PubMed1982

The effect of ascorbic acid on a proliferating cell system.

Ascorbic acid, alone and in combination with copper sulphate, was injected into the sub-blastodermal space in the early chick embryo at 17 hours of incubation. There was a marked stunting of the embryonal axis. The absence of interphase cells indicate that ascorbic acid is lethal to the resting cell and results in a reversal of differentiation. Copper counteracts the effect of ascorbic acid and protects the blastoderm when given before ascorbic acid. A parallel action in neoplasia is of importance in the therapeutic use of this vitamin.

Animals↗
PubMed1978

A neuronal nucleolar trigger mechanism traceable by a routine staining method.

In experimental Wilson's disease produced by the intracardiac injection of copper sulphate, it is seen that the glia-neuronal interactions play an important role in the pathogenesis of neural lesions. A "trigger" copper-RNA particle is transferred from the oligodendroglial nucleus to activate the neuronal nucleolus causing a flooding of the neurone with RNA. This trigger particle stains differently with Mason's trichrome, giving a bright red colour. This altered reaction gives an insight into the feedback process for the formation of ribosomal RNA in the neurones. The alteration appears to lead to a block in the repressor activity of the neuronal RNA formation.

Animals↗
PubMed1978

Mycobacterium leprae in the striated muscle of tuberculoid leprosy patients.

Striated muscle specimens from 24 untreated proved cases of tuberculoid leprosy and five healthy normal individuals were studied histopathologically for the evidence of leprous pathology. Atrophy or damage to the muscle fibre was not observed in any patient. Nineteen (79.16%) cases showed evidence of leprosy in striated muscles. Seventeen (70.83%) cases showed scanty histiocytic infiltrate between the muscle fibres. Thirteen (54.16%) cases had acid fast bacilli mostly inside the muscle. There was no correlation between the location of the bacilli and that of the histiocytes; in two cases, acid fast bacilli were seen without the histocyte. The bacilli were solidly staining and were lying singly in the undamaged muscle. There was no evidence of tuberculosis and, in the Control group, none showed any AFB or infiltrate. The presence of lepra bacilli did not depend upon the location of the muscle. Two of the muscle specimens not underneath the cutaneous lesions also had acid fast bacilli. 21.05% of these cases also showed simultaneous involvement of liver and lymph nodes. These are strong evidences of systemic nature of disease in tuberculoid leprosy as well.

Adolescent↗
PubMed1978

Bone-marrow in tuberculoid leprosy.

Twenty-four untreated patients of proved tuberculoid leprosy and five healthy controls were investigated for the involvement of bone-marrow. The cytology was essentially normal and no acid-fast bacilli was seen in the bone-marrow smears.

Adolescent↗
PubMed1977

Histogenesis of myeloid metaplasia in the spleen.

Hemopoietic activity in the spleen is caused by the proliferation of the RE cells of the red pulp, lining the sinusoids and the endothelial cells lining the venous channels and their vasa vasora. The RE cells of the marginal zone do not contribute. As the cells involved line blood spaces, and the immature cells are washed into the circulation hemopoiesis appears to be intravascular. Different agents produce different effect: copper sulphate an early proliferation of both the red pulp and venous cells, phenylhydrazine a red pulp proliferation and antiserum a high venous endothelial activity.

Animals↗