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Biomedical subjects

G Srivastava

Publications and source records attributed to G Srivastava.

At least 127 records · Page 7Linked to original sources
PubMed1989

Changing pattern of cutaneous tuberculosis. A prospective study.

During the past 3 years, we have seen a changing pattern of cutaneous tuberculosis, in which its incidence was recorded to show an upward trend affecting predominantly the adult men. The latter was true in reinfection--lupus vulgaris and tuberculosis verrucosa cutis, whereas a substantial number of children were victims of reactivation--scrofuloderma. The duration of the disease was usually short in reactivation tuberculosis. Its clinical expression, however, conformed largely to the ritual text except that apple-jelly nodules were infrequently demonstrated. Similarly, the morbidity was low. The affliction of the extremities in lupus vulgaris, in particular, was a contrasting feature. The histopathology invariably either confirmed or supplemented the clinical impression. The ultimate confirmation of cutaneous tuberculosis was done only by the demonstration of Mycobacterium tuberculosis in smears, or its recovery in vitro. In view of the limitations of the preceding parameters, the diagnosis may reasonably be made based on the history and evolution of the disease, cardinal morphologic features of reinfection and reactivation tuberculosis, and histopathologic characteristics. A response to antitubercular drugs may be of assistance.

Diagnosis, Differential↗
PubMed1988

Regulation of 5-aminolevulinate synthase mRNA in different rat tissues.

cDNA clones for rat liver 5-aminolevulinate synthase have been isolated and used to examine mRNA levels in different rat tissues. Northern hybridization analysis of total RNA from various rat tissues showed the presence of a single 5-aminolevulinate synthase mRNA species of estimated length 2.3 kilobases. Primer extension and RNase mapping studies indicated that the mRNA is identical in all tissues. Highest basal levels were seen in liver and heart. Administration of hemin to rats reduced the basal level of this mRNA only in liver but the heme precursor, 5-aminolevulinate (or its methyl ester), repressed the basal levels in liver, kidney, heart, testis, and brain. The drug 2-allyl-2-isopropylacetamide increased the mRNA level in liver and kidney only while human chorionic gonadotropin hormone elevated the level in testis. Administration of the heme precursor 5-aminolevulinate prevented these inductions. Nuclear transcriptional run-off experiments in liver cell nuclei showed that 2-allyl-2-isopropylacetamide and 5-aminolevulinate exert their effect by altering the rate of transcription of the 5-aminolevulinate synthase gene. The results indicate that a single 5-aminolevulinate synthase mRNA is expressed in all tissues and that its transcription is negatively regulated by heme.

5-Aminolevulinate Synthetase↗
PubMed1988

Histoid leprosy: a prospective diagnostic study in 38 patients.

Histoid leprosy is a fascinating expression of multibacillary leprosy, the incidence of which was 3.6%. It was seen predominantly in males of the younger age group, who were on inadequate and irregular dosage of diaminodiphenyl sulfone. Papules, cutaneous and/or subcutaneous nodules and plaques appearing over apparently normal skin were its exquisite prospective clinical features. It was invariably supported by enormous, uniformly solid staining discrete bacilli from the lesions, in contrast to their virtual absence from the surrounding normal-appearing skin. Encapsulated tumorous mass, formed primarily by spindle-shaped histocytes, displayed either in intertwining, criss-cross or whorled fashion in haematoxylin-eosin-stained sections, were supplementary. The morphology of acid-fast bacilli was, however, similar to skin-slit smears.

Adolescent↗
PubMed1988

Primary drug resistance to both rifampicin and dapsone in a paucibacillary leprosy patient.

A thirty-one year old male patient was diagnosed and treated for a pure or better primary neuritic case of leprosy with dapsone (100 mg daily for 2 years) and rifampicin (600 mg daily for 6 months). From the very outset, the patient did not show any improvement; on the top of it, he subsequently, developed a cutaneous patch, which on histopathological examination, revealed classical features of BT leprosy. Acid-fast bacilli were absent both in skin slit smear and histologic section. A primary resistance to both dapsone and rifampicin, even in paucibacillary patient, is speculated.

Adult↗
PubMed1987

A unique gene for 5-aminolevulinate synthase in chickens. Evidence for expression of an identical messenger RNA in hepatic and erythroid tissues.

Reports to date have led to the conclusion that there are isozymes for 5-aminolevulinate synthase in the liver and erythroid tissue of chicken. Indeed, the existence of a multigene family for chicken 5-aminolevulinate synthase has been proposed. We find no evidence to support these proposals. In this work we show that 5-aminolevulinate synthase mRNA from chicken liver and reticulocytes is identical as determined by RNase mapping and primer extension studies and that the 5-aminolevulinate synthase protein from these tissues is the same size as judged by immunoblot analysis. We also show that a single mRNA species for 5-aminolevulinate synthase is present in chicken liver, reticulocytes, brain, and heart and an avian erythroblastosis virus-transformed chicken erythroblast cell line. Southern analysis shows the presence of only one gene copy for 5-aminolevulinate synthase in the chicken haploid genome. Overall, these results lead to the conclusion that in chickens 5-aminolevulinate synthase is encoded by a unique gene and is expressed as a single mRNA species in all tissues.

5-Aminolevulinate Synthetase↗
PubMed1987

An appraisal of epidemiologic, clinical, bacteriologic, histopathologic, and immunologic parameters in cutaneous tuberculosis.

Cutaneous tuberculosis incidence was recorded as 0.15%. Of the 42 patients, 23 had scrofuloderma, 17 lupus vulgaris, and 2 tuberculosis verrucosa cutis. Both men and women were affected by the disease in the second and third decades. Its duration was variable. An affirmative family history was elicited in five scrofuloderma patients. The clinical expression largely conformed to the ritual text. Variation in Mantoux test positivity was unremarkable. The disparity in the demonstration of bacilli in the smear and tissue sections was, however, quite apparent in scrofuloderma. The correlation of different parameters indicates a continuous spectrum, formed at one end by lupus vulgaris, and at another by scrofuloderma. A moderate to strongly positive Mantoux text, enormous lymphocytes in the granuloma, absence of tubercle bacilli, negative culture, and an apparently normal immunoprofile were features of lupus vulgaris; whereas scrofuloderma had a moderately positive Mantoux test, lesser number of lymphocytes in the granuloma, large number of bacilli in tissue smear and/or tissue section, raised levels of immunoglobulins, and a grossly lowered C3 levels. The other variants probably occupy a position in between.

Adolescent↗
PubMed1986

Nucleotide sequence of the chicken 5-aminolevulinate synthase gene.

5-Aminolevulinate synthase, the first and rate-controlling enzyme of heme biosynthesis, is regulated in the liver by the end-product heme. To study this negative control mechanism, we have isolated the chicken gene for ALA-synthase and determined the nucleotide sequence. The structural gene is 6.9 kb long and contains 10 exons. The transcriptional start site for ALA-synthase was determined by primer extension analysis. A fragment of 291 bp from the 5' flanking region including 34 bp of the first exon shows promoter activity when introduced upstream of a chicken histone H2B gene and injected into the nuclei of Xenopus laevis oocytes.

5-Aminolevulinate Synthetase↗