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Biomedical subjects

R M Bahu

Publications and source records attributed to R M Bahu.

13 recordsLinked to original sources
PubMed1982

Surface immunoglobulin on rabbit lymphoid cells. VII. Binding of exogenous Ig by neonatal lymphocytes and ability of aggregated Ig in neonatal sera to bind to adult cells.

The expression of endogenous and exogenous surface immunoglobulin (sIg) on the surface peripheral blood lymphocytes from adult and neonatal rabbits has been examined. Endogenous and exogenous sIg on rabbit lymphocytes differ in ultrastructural appearance and modulation characteristics. At 0 degree C immunoferritin-labeled endogenous sIg appears as small flat patches on the surface membrane whereas exogenous Ig appears as large ramose clumps. Immunoferritin-labeled endogenous Ig undergoes endocytosis at 37 degrees C, whereas exogenous Ig is shed or sloughed from the cell membrane within 60-90 min at 37 degrees C. Ig from serum or plasma which has been frozen and thawed shows a high degree of binding to peripheral blood lymphocytes, whereas Ig from fresh serum or plasma shows little or no binding. Aggregated Ig from both adult and newborn sera are able to bind to lymphocyte Fc receptors and both adult and neonatal PBLs are able to bind exogenous aggregated Ig.

Aging↗
PubMed1981

Immunologic studies of bovine aortic and cartilage proteoglycans.

Rabbit antisera prepared against bovine cartilage and aortic proteoglycan monomer (PGM) were employed to identify and localize the distribution and cross-species reactivities of these PGMs. A specific reaction to both cartilage and aortic PGM was obtained as revealed by rocket immunoelectrophoresis of the immunogens against the respective antisera, with no reaction against bovine serum albumin or human fibronectin. These antisera appear to demonstrate tissue specificity. Indirect immunofluorescence studies with antiserum to aortic PGM on bovine aorta tissue revealed intense localization of fluorescence in the intima and superficial media with staining alone collagen fibers, around smooth muscle cells, and on the surface of elastin. When antiserum to cartilage PGM was applied to bovine aorta, staining was much weaker and localized more in the interfibrillar matrix. On the other hand, when antiserum to aortic PGM was used to stain bovine nasal septum cartilage, fluorescent staining was restricted to the pericellular matrix, in contrast to the diffuse, intense staining of both pericellular and extraterritorial staining by antiserum to cartilage PGM. Absorption with eigher bovine aorta or cartilage PGM abolished antibody activity against the absorbing molecules only. The immunologic distinction between the pericellular and extraterritorial cartilage matrix was demonstrated further when both antisera were studied with guanidine chloride (GuHCl)-extracted bovine nasal septum cartilage, when they both demonstrated the same pericellular matrix staining. Despite the tissue specificity, these antisera are not completely species specific, since staining in a similar pattern was observed in both human and rat tissues.

Animals↗
PubMed1980

Detection of alpha-lactalbumin in breast lesions and relationship to estrogen receptors and serum prolactin.

Alpha-lactalbumin, the B protein of lactose synthetase secreted by the mammary epithelial cells, was isolated and purified from fresh human milk and injected into rabbits for antibody production. Indirect immunofluorescence (IIF) was done on various types of breast lesions to assess the relationship, if any, between histologic type and production of alpha-lactalbumin. Fifty percent of fibroadenomas and fibrocystic disease and 63% of infiltrating ductal carcinoma showed positive reaction. No false positives were found on IIF of alpha-lactalbumin of several tumors of nonmammary tissue. These findings suggest that IIF for alpha-lactalbumin may be helpful in ascertaining the site of origin of metastatic breast tumors. However, serum alpha-lactalbumin was detected by radioimmunoassay in only 10% of women with infiltrating ductal carcinoma, indicating that this may not be a useful marker for the presence of breast cancer at least by the method employed. This discrepancy between serum and tissue alpha-lactalbumin may be due to the short half-life of serum alpha-lactalbumin or to the lack of secretion of the protein into the blood. There was no apparent relationship between the presence of estrogen receptors or serum prolactin and alpha-lactalbumin in the 27 mammary carcinomas investigated.

Adenofibroma↗
PubMed1980

The use of antikeratin antiserum as a diagnostic tool: thymoma versus lymphoma.

Indirect immunofluorescence staining in two thymomas, one case of thymic hyperplasia, 10 malignant lymphomas and three seminomas was done with an antibody prepared against keratins from human epidermis. Staining was observed only in the epithelial cells of the thymomas and thymic hyperplasia and correlated well with electron microscopic studies. Immunofluorescence staining of thymic tumors with antikeratin antibody provides a simple, specific, and sensitive method for distinguishing thymoma from lymphoma and seminoma. The method may also prove to be useful in other instances in the distinction between epithelial and nonepithelial tumors.

Adult↗
PubMed1978

Ultrastructural changes in the liver in heatstroke.

The ultrastructural changes in the human liver 24 to 96 hours after an attack of heatstroke are described. The alterations are most obvious along the vascular pole of the hepatocytes. These consist of degenerative changes or desquamation of sinusoidal lining cells, ballooning or flattening of microvilli, breaks in hepatocyte outer membranes, and electron-lucent vacuoles along the sinusoidal border. Also noteworthy is the appearance, in a number of cases, of basement membranes or ill-defined electron-dense material which may be of basement membrane character. Sinusoidal elements, such as erythrocytes, are found in hepatocytes, and hepatocellular debris appears in sinusoids. The membranes of hepatocytes and sinusoidal lining cells thus seem to be the prime targets of the hepatic injury in heatstroke. Other changes in the hepatocytes include vesiculation of endoplasmic reticulum, detachment of ribosomes, and alterations of mitochondria. Morphologic evidence of intravascular coagulation of intravascular hemolysis is often encountered. A comparison between the findings described here and those in experimental hyperthermia suggests that many of the hepatic changes seen in heatstroke are due to an excessively high tissue temperature per se but that some of the alterations are probably a consequence of complicating factors such as hypoxia, intravascular hemolysis, or disseminated intravascular coagulation.

Heat Exhaustion↗
PubMedDate not supplied

Ultrastructure of the nervous system.

Within the nervous system, five cell types were studied by the electron microscope: the neuron, astrocyte, oligodendroglia, microglia and ependymal cells. The neurons are characterized by the Nissl substance within the perikaryon, the neurotubules and the neurofilaments. The three types of glial cells can be distinguished from one another. The astrocyte has relatively lucent cytoplasm and contains filaments which extend into long cytoplasmic processes. The oligodendroglia has electron-dense cytoplasm with thin extensions wedged between the cellular processes of the neuropil. The microglia cytoplasm is similar to the oligodendroglia but can be differentiated by the peculiar convoluted outline of the nuclear membrane and the clear space which separate the nucleus from the cytoplasm. The ependymal cell has characteristic microvilli and cilia at its ventricular surface. The cytoplasm contain parabasal bodies and tight junctions between adjacent cells. In the peripheral nerve, the axon and the myelin sheath are located within the Schwann cells. The terminal nerve endings from enlargements filled with synaptic vesicles. Electron microscopy of the nervous system is not only essential for research, but is also helpful in diagnosis of certain diseases.

Astrocytes↗
PubMedDate not supplied

Estradiol receptor assays in normal and neoplastic tissues. A possible diagnostic acid for tumor differentiation.

Estradiol (E2) binding activity was studied in several normal tissues and neoplasias of humans and experimental animals. Positive E2 binding was seen in 37 percent of breast primary malignancies, 50 percent of breast cancer metastasis to other organs, and 55 percent of breast cancer metastasis to lymph nodes. Two other tumors, renal cell carcinomas and thyroid adenocarcinomas, also had a high percent of E2 binding activity. No difference was evident histologically between the tumors which were positive and those which were negative. Elevated E2 binding activity was seen in normal liver and pancreas of rats and mice as well as in an experimentally induced acinar pancreatic carcinoma of the rats. These preliminary results indicate that the measurement of estradiol receptors should be extended to other neoplasias than breast cancer, and it may give some indication about the evolution and the hormonal controls of the tumors themselves.

Adrenal Gland Neoplasms↗