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Biomedical subjects

G Singh

Publications and source records attributed to G Singh.

At least 649 records · Page 36Linked to original sources
PubMed1986

Observations on long-term follow-up of posterior scleritis.

Clinical features of posterior scleritis were noted in 12 eyes of nine patients followed up for one to seven years. The signs of this clinical entity varied from transitory choroidal folds in the fundus to extensive scleral and choroidal edema with associated edema of Tenon's space and of the optic nerve sheath. These were detected only by ultrasonography. Histopathologic examination of one eye disclosed granulomatous inflammatory reaction in the involved scleral and choroidal areas. Local and systemic treatment with corticosteroids seemed not to affect the clinical course or outcome.

Adolescent↗
PubMed1986

The pathobiologic features of carcinomas of type II pneumocytes. An immunocytologic study.

Adenocarcinomas of the lung without squamous differentiation or obvious mucus production from 51 patients were studied. Twenty-eight tumors (55%), when stained with rabbit anti-human surfactant apoprotein antiserum by the peroxidase-antiperoxidase method, demonstrated characteristic nuclear inclusions. Most of these tumors could be identified histochemically by the presence of eosinophilic, periodic acid-Schiff (PAS)-positive nuclear inclusions. In patients with apoprotein-immunoreactive tumors there were nine deaths due to tumor (32%) within 5 years of diagnosis. Eight of the nine deaths occurred in patients whose tumors exceeded 3 cm in diameter; an equal number of patients were smokers. The average age of patients with apoprotein-positive tumors was 67.3 years, a figure greater than that for patients with apoprotein-negative tumors (61.4 years). Five of the 23 patients with apoprotein-negative tumors died of their neoplasms; in two of the subjects the tumors exceeded 3 cm in diameter. In that no significant difference in survival was observed in patients with apoprotein-positive and apoprotein-negative tumors, it was concluded that subclassification of adenocarcinomas of the lung as apoprotein-positive, i.e., type II pneumocytic, or as apoprotein-negative, is of no clinical or prognostic significance. Nonetheless, peripheral tumors measuring less than 3 cm in size and showing neither squamous differentiation nor obvious mucus production should be recognized as a prognostically favorable group in comparison with other types of lung carcinomas.

Aged↗
PubMed1986

Effect of fatty acids on aflatoxin production by Aspergillus parasiticus.

The effect of saturated and unsaturated fatty acids on aflatoxin production was studied in a synthetic medium. The aflatoxin production decreased (10-75%) in the presence of lauric acid and palmitic acid but the addition of behenic and sebacic acid stimulated aflatoxin production by 125-541%. Linolenic and linoleic acids effected aflatoxin production and mycelium growth. An 34-fold increase in aflatoxin production was observed with 50 mM linoleic acid. An inverse relationship was observed between aflatoxin production and mycelium mass, irrespective of the nature of the fatty acid.

Aflatoxins↗
PubMed1986

Effect of metal ions on aflatoxin production by Aspergillus parasiticus.

The effect of iron, copper, cobalt, cadmium, zinc, molybdenum, magnesium and manganese salts was studied on aflatoxin production in relation to mycelial mass. Iron, copper and cadmium salts decreased the aflatoxin production to different levels but a mixed trend was observed depending on salt concentration, with molybdenum, magnesium and manganese. Cobalt and zinc salts stimulated aflatoxin production at all concentrations studied. The maximum increase in aflatoxin production, 655% and 519% was observed in the presence of zinc sulfate and sodium molybdate, respectively. A negative correlation was observed between aflatoxin production and vegetative growth of fungus.

Aflatoxins↗
PubMed1986

Papillary adenoma of type 2 pneumocytes.

A case of papillary adenoma of type 2 pneumocytes is reported. A 57-year-old man had an unusual coin lesion in the periphery of the right lung without any symptoms. When detected in a mass survey examination, it was approximately 1.5 cm in diameter, well circumscribed, and located in S4, involving the sixth-order bronchus of B4. Light-microscopic examination revealed cuboidal tumor cells arranged in a papillary pattern. Ultrastructurally, the cells had characteristic osmiophilic lamellar bodies. By immunoperoxidase staining, the tumor cells were shown to have intracytoplasmic surfactant apoproteins. The postoperative course was uneventful, and there is no evidence of disease 8 years later.

Cystadenoma↗
PubMed1986

Drug resistance patterns and susceptibility to aflatoxin B1 of strains of Escherichia coli and Staphylococcus aureus.

The antibacterial properties of aflatoxin B1 have been evaluated against antibiotic-resistant clinical isolates of Escherichia coli and Staphylococcus aureus. The inhibition of growth ranged from 11.5 to 60.0% and 4.5 to 18.5% in the strains of S. aureus and E. coli, depending on the extent of drug resistance. Aflatoxin-B1 binding varied with toxin concentration, the presence of surfactants (Tween-80 or EDTA) as well as with the antibiotic-resistance pattern; binding was maximal in antibiotic-sensitive strains and least in the most resistant strains. Binding of aflatoxin B1, correlated with growth inhibition. Aflatoxin B1 also caused leakage of cell contents and decrease in inulin uptake, effects which were also concentration dependent.

Aflatoxin B1↗
PubMed1986

Tachyphylaxis to topical steroid measured by histamine-induced wheal suppression.

Ten healthy volunteers were studied to find out whether tachyphylaxis occurs on repeated application of topical steroids. The Singh and Singh modification of the Reddy and Singh (1976) technique was used. Fluocinolone acetonide cream (0.1%) under occlusion was applied daily for 14 days on the flexor aspect of the forearms. The wheal was induced by pricking with histamine acid phosphate solution and the volume of the wheal produced was calculated. The test was repeated on the same sites on alternate days for 14 days. The maximum wheal suppression, which gradually diminished, was observed on the 8th day. By the 14th day, there was practically total tolerance to topical steroid, which showed minimal suppression of histamine wheal formation. This confirms the occurrence of the phenomenon of tachyphylaxis by different experimental techniques.

Administration, Topical↗
PubMed1986

A quantitative assay for a Clara cell-specific protein and its application in the study of development of pulmonary airways in the rat.

Rat lung lavage contains a 10 kDa protein that has been shown by immunocytochemistry to be specific for Clara cells. An inhibition enzyme-linked immunosorbent assay was established for this protein using rabbit antibody to the 10 kDa Clara cell protein. The assay has a sensitivity of about 3.0 ng/ml and a working range of about 5 to 50 ng/ml. Quantitation of the 10 kDa protein in amniotic fluid revealed an increase of about 4-fold at day 20 of gestation. The 10 kDa protein content of lung homogenate increased steadily from day 18 of gestation to 1 wk after birth, after which a decline was observed. Nearly 60-fold increase in the concentration of the 10 kDa Clara cell protein in lungs was noted from day 18 of gestation to birth and a further about 7-fold increase was noted from the day of birth to 1 wk of age. A progressive increase in the 10 kDa protein, with increasing age, was also noted on immunoblot analysis of lung homogenates. As judged from the immunoblots of lung homogenates, stained with rabbit antirat 10 kDa protein antiserum, the content of an antigenically similar 200 kDa Clara cell protein was negligible. The quantitative results for 10 kDa Clara cell protein parallel the results of immunocytochemistry and quantitation of the volume density of Clara cell granules indicating that quantitation for the 10 kDa protein could be used to monitor the development of Clara cells and that of the pulmonary airways.

Amniotic Fluid↗
PubMed1986

Leber's disease and dystonia: a mitochondrial disease.

We studied a kindred in which 8 members had the neuroretinopathy of Leber's disease; 14 had a progressive, generalized dystonia attributed to striatal degeneration; and 1 had both disorders. The mode of inheritance was compatible with maternal transmission. This neurologic disorder may be a mitochondrial disease.

Adolescent↗
PubMed1986

Antibody to collagen type I in periodontal disease.

Serum antibody levels to human collagen Type I were measured in 97 patients with periodontal disease (Russell Periodontal Index 1.0-7.0) and 57 control subjects (Periodontal Index less than 1.0) using an enzyme-linked immunosorbent assay, which had been standardized with antisera prepared against human collagen Type I in rabbits. Absorption studies were used to confirm the specificity of antibodies to human Type I collagen. Levels of antibody to Type I collagen detected in patients were higher (P less than 0.001) than in the control subjects.

Adult↗
PubMed1986

Characterization of rat alveolar type II cells in vitro by immunological, biochemical, and morphological criteria.

Using an anti-rat surfactant apoprotein antiserum which specifically reacts with cytoplasmic structures in alveolar type II cells on histopathology sections of rat lung, we have examined the immunoreactivity of pulmonary type II cells in vitro. Single cell suspensions of lung tissue were prepared from male Fischer 344 rats by intratracheal elastase digestion according to standard published methods. Cytocentrifuged preparations of the resulting cell suspensions revealed that approximately 40% of the cells stained positive for surfactant apoprotein using an immunoperoxidase staining technique. Without further cell fractionation steps, the cell suspensions were plated at colonial densities in growth medium. The cells that attached after 24 hours of incubation and at daily intervals were analyzed for surfactant apoprotein immunoreactivity as well as for proliferation, morphology, and phospholipid biosynthesis. The percentage of immunopositive cells increased with time from 75% at day 1 to 94% at 4 days after plating. This increase was paralleled by a linear increase in the number of immunopositive cells, which expanded into cell colonies. During the initial 5 days in vitro, the immunopositive cells retained their epithelial morphology and contained cytoplasmic osmiophilic bodies. Phospholipid biosynthesis by the isolated lung cells was analyzed and the data revealed that the rate of incorporation of 14C-choline into phosphatidylcholine increased with time in culture. These studies indicated that the anti-rat surfactant apoprotein antisera can be used to identify and quantitate functional alveolar type II cells in vitro. Thus the specific antisera may facilitate studies of type II cells undergoing various environmental alterations both in vivo and in vitro.

Animals↗
PubMed1986

An outbreak of typhoid fever in Chandigarh, North India.

An outbreak of typhoid fever occurred among 54 hospital nurses after a picnic. The salient features were fever (100%), nausea and vomiting (46%), loose motions and abdominal pain (13%), and palpable splenomegaly (63%). None of the patients had any major complications. Blood cultures for Salmonella typhi were positive in 81%, blood Widal was positive (1:320 or more) in 43% and suggestive (1:160) in 25% of the blood culture positive patients. A comparable number of patients were administered chloramphenicol or co-trimoxazole and no differences in response were observed. Bacteriological examination of samples of water from the likely sources revealed it to be unfit for human consumption due to gross faecal contamination.

Adolescent↗
PubMed1986

Mitosis and cell division in human corneal endothelium.

During routine morphologic evaluation of nine human corneas, obtained from cadavers of persons older than 40 years, numerous endothelial cells were observed undergoing changes similar to those seen during mitotic cell division. An inverted phase-contrast microscope was used to examine the corneal endothelium, and trypan blue vital stain was used to assess cellular viability. Changes noted within the cell and the nucleus were documented photomicrographically. These findings support the hypothesis that cell division and mitosis do occur in human corneal endothelium.

Adult↗