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Biomedical subjects

V K Vijayan

Publications and source records attributed to V K Vijayan.

At least 55 records · Page 3Linked to original sources
PubMed1991

Effect of diethylcarbamazine on the alveolitis of tropical eosinophilia.

Bronchoalveolar lavage studies in 33 patients with acute untreated tropical eosinophilia have demonstrated intense eosinophilic alveolitis. Following treatment with a standard 3-week course of diethylcarbamazine, there was a significant fall in lung eosinophils (p less than 0.001). However, a mild alveolitis characterised by hypercellular lavage fluid due to a significant increase in absolute alveolar macrophages (p less than 0.001) and due to an increase in both the absolute number (p less than 0.01) and percentage of eosinophils (p = 0.02) was persisting at 1 month despite treatment. Long-term follow-up is essential to know the fate of alveolitis.

Acute Disease↗
PubMed1991

Correlation of lower respiratory tract inflammation with changes in lung function and chest roentgenograms in patients with untreated tropical pulmonary eosinophilia.

Forty-one patients with untreated tropical pulmonary eosinophilia (TPE) were studied to determine whether there was any relationship between lower respiratory tract inflammation and either changes in lung function or abnormalities in chest roentgenograms. Total number of inflammatory cells in bronchoalveolar lavage (BAL) fluid, consisting of alveolar macrophages, lymphocytes, eosinophils and neutrophils had significant negative correlations with transfer factor (TLCO) (r = 0.519, p less than 0.001), transfer coefficient (KCO) (r = 0.312, p less than 0.05) and total lung capacity (TLC) (r = 0.352, p less than 0.05). The absolute count of eosinophils in BAL fluid had a significant negative correlation with TLCO (r = 0.430, p less than 0.01) and KCO (r = 0.300, p = 0.05), but not with forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1) or TLC. However, the absolute count of alveolar macrophages had a significant negative correlation with FVC (r = 0.343, p less than 0.05), FEV1 (r = 0.341, p less than 0.05) and TLC (r = 0.305, p less than 0.05), but not with TLCO or KCO. The total number of lymphocytes had a negative correlation with TLC (r = 0.315, p less than 0.05). There was no correlation between the types of cells recovered in BAL fluid and changes in chest radiographs as assessed by the ILO classification for occupational lung diseases. These data suggest that there may be a dissociation of pulmonary pathophysiological changes produced by different inflammatory cells in the lower respiratory tract. Macrophages and lymphocytes may produce more harm to the lung, as evidenced by significant negative correlations of these cells with lung volumes.

Adolescent↗
PubMed1990

Brain isozyme of glycogen phosphorylase: immunohistological localization within the central nervous system.

An antibody specific for the predicted carboxyterminal sequence of the human brain isozyme of glycogen phosphorylase (alpha-1,4-D-glucan:orthophosphate D-glucosyltransferase, EC 2.4.1.1) was generated to verify the carboxyterminal amino acid sequence of this protein. The isozyme-specific antibody was used to examine the localization of this protein in primate and non-primate brain. The highest levels of the brain isozyme in cerebrum and cerebellum were found in fibrous astrocytes, many with glial processes that appear to terminate upon blood vessels.

Animals↗
PubMed1990

Long-term survival of neural transplants to senescence in rats.

A critical issue for clinical and research applications of transplant techniques is the long-term survival of transplanted tissue and its effect on the host brain. In this study, entorhinal cortices from donor embryos were transplanted into the lesioned angular bundle of juvenile male Sprague-Dawley rats. Animals were maintained for 2 years and then sacrificed for histological and histochemical examinations. The results indicate that entorhinal transplants survive to old age and that both the host and transplant tissues maintain morphological features consistent with those of short-term neural grafts. An unexpected finding of this experiment was the persistence in the transplanted tissue and adjacent host cortex of a pattern of AChE staining which is typical of early postnatal development.

Acetylcholinesterase↗
PubMed1990

Five year results of a 3-month and two 5-month regimens for the treatment of sputum-positive pulmonary tuberculosis in south India.

A controlled study of three short-course regimens was undertaken in South Indian patients with newly diagnosed, sputum-positive pulmonary tuberculosis. The patients were allocated at random to one of three regimens: a) Rifampicin, streptomycin, isoniazid and pyrazinamide daily for 3 months (R3); b) the same regimen as above but followed by streptomycin, isoniazid and pyrazinamide twice-weekly for a further period of 2 months (R5); c) the same as R5 but without rifampicin (Z5). A bacteriological relapse requiring treatment occurred by 5 years in 16.8% of 113 R3, 5.2% of 97 R5, and 20.0% of 115 Z5 patients with organisms sensitive to streptomycin and isoniazid initially. The differences in the relapse rates between the R3 and R5 regimens and the R5 and Z5 regimens were statistically significant (p less than 0.01 for both). Considering patients with organisms initially resistant to streptomycin or isoniazid or both, 7 of 52 patients (4 R3, 2 R5, 1 Z5) had a bacteriological relapse requiring retreatment.

Adolescent↗
PubMed1990

Pulmonary function in healthy young adult Indians in Madras.

Forced vital capacity, forced expiratory volume in one second, functional residual capacity, residual volume, total lung capacity, and single breath diffusing capacity measurements (effective alveolar volume, carbon monoxide transfer factor, and transfer coefficient) were measured in 247 young healthy adults (130 male, 117 female) aged 15-40 years living in Madras. Subjects were of Dravidian stock, living at sea level with rice as their staple diet. Regression equations were derived for men and women for predicting normal pulmonary function for young adults in South India. The values were similar to those reported for subjects from Western India and lower than those reported for North Indians and caucasians.

Adolescent↗
PubMed1990

Persistent lower respiratory tract inflammation associated with interstitial lung disease in patients with tropical pulmonary eosinophilia following conventional treatment with diethylcarbamazine.

Tropical pulmonary eosinophilia (TPE) presents as an acute syndrome with dyspnea, fluffy infiltrates, and rounded opacities on the chest radiograph, reduced lung function, marked eosinophilia in the blood and lower respiratory tract, and high titers of specific IgE and IgG antifilarial antibodies. The standard therapy for TPE is a 3-wk course of diethylcarbamazine (DEC) following which there is almost always a marked improvement in all parameters. However, clinical observations suggest that the disease can persist despite DEC therapy and lead to chronic dyspnea with restrictive lung impairment. To evaluate the concept that DEC therapy is not completely "curative" for TPE, but rather leaves most individuals with a mild, chronic form of TPE defined by persistent inflammation of the lower respiratory tract, we evaluated 23 individuals an average of 12 +/- 2 months following a standard 3-wk course of diethylcarbamazine for acute TPE. In the majority there were mild, persistent symptoms referrable to the lung, chest X-ray abnormalities, blood eosinophilia, and elevated serum IgE and filarial specific IgG. On the average, lung function was consistent with the presence of chronic, mild interstitial lung disease. When the inflammatory cells from the lower respiratory tract were examined, there was a persistent eosinophilic alveolitis (TPE/post-DEC 1769 +/- 376 eosinophils/microliters epithelial lining fluid; normal subjects 256 +/- 38, p less than 0.02). Evaluation of the lower respiratory tract inflammatory cells recovered from the TPE/post-DEC-treated individuals demonstrated spontaneous release of exaggerated amounts of O2-. and H2O2 compared to normal subjects (p less than 0.05, both comparisons).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1989

Trauma-induced proliferation of astrocytes in the brains of young and aged rats.

The time-course and magnitude of astrocyte proliferation following neural trauma was evaluated in young adult (3 months) and mid-aged (16-19 months) male Fischer 344 rats. One to 4 days after a needle wound was made through the cortex and the hippocampus, rats received three intraperitoneal injections of 3H-thymidine at 8 hour intervals and were sacrificed 1 hour after the last injection. For astrocyte quantification, 3H-thymidine autoradiography was combined with immunohistochemical staining for glial fibrillary acidic protein followed by semithin sectioning. In areas of the cortex and hippocampus adjacent to the wound, astrocytes were categorized as unlabeled or labeled with silver grains over the nuclei. Labeling index and numerical density of astrocytes were determined using stereological methods. The results showed that in both young and older rats, astrocyte proliferation is an early glial response to neural trauma, occurring during the first 4 postlesion days and contributing to an increase in astrocyte population. Regional differences in labeling index and numerical density suggest heterogeneity in the proliferative capacity of astrocyte subpopulations in the rat brain. Compared with young animals, older rats demonstrated greater labeling in the cortex but not in the hippocampus. Thus, aging is associated with region-specific increase in astrocyte reactivity to trauma possibly due to increased availability of mitogens or enhanced sensitivity of astrocytes to mitogenic signals.

Aging↗
PubMed1989

Treatment of pulmonary tuberculosis with short course chemotherapy in south India--5-year follow up.

A controlled clinical trial of three short-course chemotherapy regimens was undertaken in patients with newly diagnosed bacteriologically positive pulmonary tuberculosis. The patients were randomly allocated to receive one of three regimens: rifampicin, streptomycin, isoniazid and pyrazinamide daily for 2 months, followed by streptomycin, isoniazid and pyrazinamide twice weekly for 3 months (R/5) or for 5 months (R/7), or the same regimen as R/7 but without rifampicin (Z/7). A bacteriological relapse requiring retreatment occurred by 5 years in 7.1% of 126 R/5, 4.0% of 124 R/7 and 6.7% of 253 Z/7 patients with organisms initially sensitive to streptomycin and isoniazid; none of these differences is statistically significant. Of the 31 relapses, 16 occurred within 2 years of the completion of chemotherapy and the remaining 15 between 2 and 5 years. Among 65 patients with initial drug resistance to streptomycin or isoniazid or both, there were six bacteriological relapses requiring retreatment.

Adolescent↗
PubMed1989

Tropical pulmonary eosinophilia: analysis of antifilarial antibody localized to the lung.

Acute tropical pulmonary eosinophilia (TPE) is characterized by wheezing, pulmonary infiltrates, marked peripheral blood eosinophilia, and very high serum levels of filaria-specific antibodies. To evaluate the amount and character of the filaria-specific antibodies in the lungs in this disorder, bronchoalveolar lavage was carried out in individuals with acute TPE, in normal subjects, and in patients with elephantiasis or asthma. Striking elevations of total IgE were found in the lower respiratory tract epithelial lining fluid (ELF) of patients with TPE along with high levels of filarial-specific IgG, IgM, and IgE. When patients with acute TPE were treated with diethylcarbamazine and evaluated again 6-14 d later, there was marked reduction in ELF parasite-specific IgG and IgE, which paralleled a rapid clinical response. Immunoblot comparison of the antigen recognition patterns of ELF and serum antibodies demonstrated a general similarity in parasite antigens recognized, but the lung IgE and IgG antibodies appeared to recognize only a certain subset of the parasite antigens recognized by serum antibodies. Thus, a profound antibody response to filarial infection is found in the lungs of patients with TPE, suggesting that these filaria-specific antibodies play an important role in the pathogenesis of this disorder.

Acute Disease↗
PubMed1989

Bronchoalveolar lavage study in victims of toxic gas leak at Bhopal.

Bronchoalveolar lavage using flexible fibreoptic bronchoscope was carried out in 50 patients 1-2 1/2 yr after exposure to the 'toxic gas' at Bhopal. Thirty six patients in the analysis were categorised into 3 groups (viz., mild, moderate and severe), depending upon the severity of exposure. There was an increase in cellularity in the lower respiratory tract (alveolitis) of the severely exposed patients (in both smokers and non-smokers), compared to normals (P less than 0.05). The increase in cellularity in severely exposed non-smokers was due to abnormal accumulation of macrophages (P less than 0.01), and in severely exposed smokers, to macrophages (P less than 0.01) and neutrophils (P less than 0.05). Mild and moderately exposed patients did not show significant change in cellularity in lower respiratory tract, compared to normal individuals (P greater than 0.2). There was a trend towards increasing cellularity, as the severity increased (P less than 0.0001) and higher numbers of total cells were seen in severely exposed smokers, suggesting that smoking is a risk factor. It appears, therefore, that subjects severely exposed to the toxic gas at Bhopal may have a subclinical alveolitis characterised by accumulation and possibly activation of macrophages in the lower respiratory tract. Smokers, who were exposed to the gas had in addition, accumulation of neutrophils.

Accidents, Occupational↗
PubMed1988

Application of glial fibrillary acidic protein immunohistochemistry in the quantification of astrocytes in the rat brain.

Immunohistochemical staining for glial fibrillary acidic protein (GFAP) was employed as a tool for quantification of astrocytes in the rat brain. One-micron-methacrylate sections were prepared from 70-micron slices stained for GFAP by using a preembedding staining procedure. Numbers/unit area of astrocytes and nonastrocytes were determined for cortex, corpus callosum, and hippocampal neuropil. In each, counts from GFAP-stained, toluidine-blue-counterstained sections were compared with counts obtained from sections stained with toluidine blue alone. Numbers of nonastrocytes and total glia in all three regions were comparable in both groups of sections. Astrocyte counts in the cortex and hippocampus also showed no significant differences between the two groups. In contrast, the number of astrocytes in the corpus callosum was significantly lower in GFAP-stained, toluidine-blue-counterstained sections than in sections stained with toluidine blue alone. GFAP immunohistochemistry is a useful tool for the quantification of astrocytes in semi-thin plastic sections of rat brain.

Animals↗
PubMed1987

Hydrocortisone administration alters glial reaction to entorhinal lesion in the rat dentate gyrus.

Young adult male rats received subcutaneous implants of Alzet osmotic minipumps which delivered 400 micrograms hydrocortisone per day. Untreated rats received no pumps or pumps containing the vehicle. Five days after receiving the implantation, both groups of rats were subjected to unilateral entorhinal lesion. Seven days after surgery, brains were analyzed quantitatively for glial changes in the denervated dentate outer molecular layer. Numerical densities of astrocytes and nonastrocytic glia were calculated by cell counting using 1.0-micron toluidine blue-stained sections. Glial acid phosphatase staining was quantitated using computer-assisted cytophotometric measurement of individual glial cells. Hydrocortisone-treated animals demonstrated 31% more astrocytes and 22.4% less nonastrocytes in the dentate outer molecular layer compared with untreated animals. Glia in the treated animals also showed a 33% decrease in average optical density of cytoplasmic acid phosphatase staining. These findings suggest that hydrocortisone treatment prior to and following an entorhinal lesion accelerates lesion-induced migration of astrocytes to the outer molecular layer, and reduces the increase in microglial number resulting from the lesion. The observed effect on microglia may result from a direct hormonal inhibition of local proliferation of microglia or from the well known systemic anti-inflammatory action of glucocorticoids on monocytes, the putative precursors of brain microglia. Our findings suggest that glucocorticoid hormones significantly alter the response of non-neuronal cells to neural tissue damage.

Acid Phosphatase↗
PubMed1987

Acute tropical pulmonary eosinophilia. Characterization of the lower respiratory tract inflammation and its response to therapy.

Although acute tropical pulmonary eosinophilia (TPE) is well recognized as a manifestation of filarial infection, the processes that mediate the abnormalities of the lung in TPE are unknown. To evaluate the hypothesis that the derangements of the lower respiratory tract in this disorder are mediated by inflammatory cells in the local milieu, we utilized bronchoalveolar lavage to evaluate affected individuals before and after therapy. Inflammatory cells recovered from the lower respiratory tract of individuals with acute, untreated TPE (n = 8) revealed a striking eosinophilic alveolitis, with marked elevations in both the proportion of eosinophils (TPE 54 +/- 5%; normal 2 +/- 5%; P less than 0.001) and the concentration of eosinophils in the recovered epithelial lining fluid (ELF) (TPE 63 +/- 20 X 10(3)/microliter; normal 0.3 +/- 0.1 X 10(3)/microliter; P less than 0.01). Importantly, when individuals (n = 5) with acute TPE were treated with diethylcarbamazine (DEC), there was a marked decrease of the lung eosinophils and concomitant increase in lung function. These observations are consistent with the concept that at least some of the abnormalities found in the lung in acute TPE are mediated by an eosinophil-dominated inflammatory process in the lower respiratory tract.

Adult↗
PubMed1986

Morphogenesis of the mossy fiber synapses in the hippocampus of the rhesus monkey.

Morphogenesis of the hippocampal mossy fiber synapses (MFSs) in fetal and postnatal rhesus monkeys was examined by electron microscopy. Typical invaginated MFSs were absent on gestation days 90 and 109 and were detected infrequently on day 132. In older fetuses and postnatal animals of 16 days and 9 months of age, the percentage of invaginated MFSs increased and the synapses exhibited increases in the number of invaginated spines and density of synaptic vesicles and greater maturity of the spines. At all ages, MFSs exhibited a wide range of maturity which may be correlated with the reported protracted generation of dentate granule cells in the rhesus monkey. The pattern of morphogenesis of MFSs in the monkey suggests that as in the rat, it is very likely that the mossy fibers contact pyramidal cells prior to the emergence of the 'thorny excrescences' and that this is followed by progressive maturation of the MFSs. The time-course of major morphogenetic modifications in MFSs in the rhesus monkey corresponds to the period of elaboration of complex spines and synapses in the dentate molecular layer. On this basis, it is suggested that these two processes are interrelated developmental events.

Animals↗
PubMed1984

Morphometric effects of exposure to lead during the preweaning period on the hippocampal formation of aging rats.

Our previous morphologic studies in the rat demonstrated that exposure to lead during the preweaning period induced delays in the maturation of late-developing regions of the hippocampal formation at 15 days of age, followed by normal development or hypertrophy of the same areas in young adulthood. The present study was carried out to determine whether or not subtle or latent effects of such exposure to lead may be unmasked with the additional challenge of aging. To do this, mid-dorsal sections of the hippocampal formation from middle-aged (578-631 days old) Long-Evans control rats and from rats exposed to lead from birth until weaning via dams drinking 0.2% lead acetate were analyzed by light and electron microscopy. Exposure to lead did not alter areas of either neuropil or neuronal layers of the hippocampus or the dentate gyrus or the numbers per section or numerical densities (numbers per unit area) of neurons in hippocampal CA3 stratum pyramidale or dentate stratum granulosum. It did reduce mean size of complex invaginated mossy fiber synapses without altering their numbers in the proximal (close to dentate gyrus) mossy fiber zone, which was the zone also affected at 15 and 90 days of age in our previous studies.

Age Factors↗