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Biomedical subjects

M Mathur

Publications and source records attributed to M Mathur.

At least 109 records · Page 6Linked to original sources
PubMed1992

Cryptosporidiosis in east Delhi children.

A total of 350 stool samples from children below 3 yrs. of age with diarrhoea (Group I), matched controls (Group II) and persons between age group 4-30 years with diarrhoea (Group III) were examined for cryptosporidium oocysts. Cryptosporidium was detected only in children with diarrhoea. Infection was predominant in males so this study suggests that cryptosporidium is a cause of diarrhoea in children and the necessity of routine laboratory investigation for diagnosis of the condition.

Adolescent↗
PubMed1992

A study of Helicobacter pylori in north Indian subjects with non-ulcer dyspepsia.

A prospective case control study was conducted in 50 patients with non-ulcer dyspepsia (NUD) and 10 age and sex matched controls to determine the prevalence of Helicobacter pylori in patients with NUD and to correlate symptoms, histology and presence of H pylori in gastric biopsies. Endoscopic biopsies from antrum and fundus were subjected to urease test and histological examination. On histology, H pylori was identified in 27 (54%) NUD patients and in one of 10 controls. Urease test was positive in 31 (62%) antral and 21 (42%) fundal biopsies in patients with NUD and in only one (10%) of 10 antral biopsies in the control group. On histology, gastritis was present in the antrum in 46 (92%) NUD patients and in the fundus in 40 (80%) cases; of these, 27 (54%) and 15 (30%) had H pylori in antral and fundal biopsies respectively. The severity of antral gastritis correlated with the density of H pylori (p < 0.05).

Adolescent↗
PubMed1992

Aflatoxin B1 induced hepatocarcinogenesis in neonatal rats.

Role of cell replication on aflatoxin B1 (AFB1) induced hepatocarcinogenesis was investigated in neonatal rats showing persistence of cell replication in the liver for 21 days of post natal life. Adult (8-10 weeks old) rats displaying no hepatocytic proliferation served as controls. Three doses of AFB1 were administered to both the groups at intervals of 48 hr with the doses starting on 10th day of age in the neonatal group. Appearance of phenotypically altered preneoplastic hepatocytes was quantitated in both the groups. A significantly higher incidence of preneoplastic foci was recorded in neonatal rats as compared to adult animals. The results suggest that presence of cell replication in neonatal rats at the time of AFB1 administration enhances the process of hepatocarcinogenesis.

Aflatoxin B1↗
PubMed1992

A prospective randomized study of the injurious effects of aspirin and naproxen on the gastroduodenal mucosa in patients with rheumatoid arthritis.

A prospective double-blind randomized placebo-controlled study was conducted to compare the injurious effects of aspirin and naproxen on the gastroduodenal mucosa. Patients with rheumatoid arthritis attending the immunology clinic of a tertiary care center were included in the study. Ninety consecutive patients were randomized to receive aspirin, naproxen, or placebo. Clinical evaluation was done every 2 wk. Upper gastrointestinal endoscopy, biopsies from the gastric antrum and duodenum for histological examination, and Helicobacter pylori studies were done at entry and after 2 months. The number of patients with dyspeptic symptoms was similar in the aspirin (12) and naproxen (9) groups. In both cases, however, it was higher (p less than 0.01) than in the placebo group (none). Naproxen was associated with a higher score of endoscopic abnormalities in the gastric body (0.6 +/- 1.3) than aspirin (0.2 +/- 0.6) or placebo (0.03 +/- 0.18). H. pylori was present in a similar proportion of patients in the three groups (33-43%). A greater fall in hemoglobin was observed with aspirin (0.35 +/- 0.48 g%) and naproxen (0.44 +/- 0.53 g%) than with placebo (0.09 +/- 0.4 g%). The present study suggests that aspirin and naproxen produce a similar degree of injury to the gastroduodenal mucosa.

Adult↗
PubMed1991

Phytohormonal regulation of S-adenosylmethionine synthetase and S-adenosylmethionine levels in dwarf pea epicotyls.

A significant stimulation (2- to 2.5-fold) of AdoMet synthetase was witnessed in glibberellicd acid (GA3, 1 microM)-treated epicotyls of the dwarf pea (Pisum sativum). This was accompanied by a 2.4-fold increase in the endogenous pool of S-adenosylmethionine. Both abscisic acid (10 microM) and cycloheximide (20 micrograms/ml) inhibited the GA3-mediated enhancement of AdoMet synthetase activity. Three isozymes of AdoMet synthetase were detected in GA3-treated epicotyls, whereas a single activity peak was observed in controls. Thus, GA3 seems to control the induction of two new isozymes of AdoMet synthetase in the dwarf pea. By contrast, the tall pea exhibited three isozymes of AdoMet synthetase even in the absence of GA3 treatment. High concentration of L-methionine (2 mM) mimicked the GA3-elicited induction of two new isozymes of AdoMet synthetase in dwarf pea epicotyls.

Abscisic Acid↗
PubMed1991

Post-transcriptional regulation of S-adenosylmethionine synthetase from its stored mRNA in germinated wheat embryos.

About 2-3-fold stimulation of S-adenosylmethionine synthetase was witnessed in germinated wheat embryos (48 h). The enhancement of enzyme activity was significantly inhibited by cycloheximide and amino acid analogues. Simultaneous addition of corresponding amino acids alleviated the inhibitory effect of amino acid analogues. Conclusive proof for the de novo synthesis of S-adenosylmethionine synthetase was obtained by labelling this enzyme with [35SO4]2- in vivo. Thus de novo enzyme synthesis seemed necessary for the rise in activity of AdoMet synthetase in wheat embryos. Curiously, blocking of transcription with cordycepin failed to repress the de novo synthesis of AdoMet synthetase in germinated wheat embryos. We envisage the presence of stored mRNA for AdoMet synthetase in wheat embryos. Thus the regulation of this enzyme occurs at the post-transcriptional level. L-Methionine, which is one of the substrates of AdoMet synthetase, stimulated the enzyme activity (2-2.4-fold) over that observed in control germinated embryos. L-Methionine promotes increased de novo synthesis of AdoMet synthetase. Preincubation of enzyme fraction with L-Methionine failed to activate or stabilize the activity of AdoMet synthetase. Three isozymes of AdoMet synthetase were physically separated by DE-52 ion-exchange chromatography. One of the isozymes of AdoMet synthetase has been purified (1529-fold) to electrophoretic homogeneity by resorting to phenyl Sepharose and ATP Sepharose affinity chromatography. The purified enzyme catalyzed the synthesis of S-adenosylmethionine and also exhibited tripolyphosphatase activity. The reaction product of the purified enzyme was chemically and enzymatically characterized as S-adenosylmethionine. The molecular weight of the native enzyme is 174,000 and that of its subunit is 84,000 as determined on SDS-PAGE. Thus the native enzyme seems to be dimeric in nature.

Acid Anhydride Hydrolases↗
PubMed1991

T cell receptor expression in Sjögren's syndrome.

T lymphocytes expressing the gamma/delta T cell receptor and B lymphocytes expressing CD5 are known to occur in expanded numbers in the peripheral blood of patients with primary Sjögren's syndrome. The cellular infiltrates for the surface phenotypic markers for alpha/beta and gamma/delta T cell receptors, CD4, CD8, CD45, and CD5 were examined in lip biopsy specimens from two patients with primary Sjögren's syndrome, six with secondary Sjögren's syndrome, and seven healthy controls. Most of the Sjögren's lip biopsy cellular infiltrates were T lymphocytes of the CD4 subset expressing the alpha/beta T cell receptor (mean 70%). The low prevalence of gamma/delta T cell receptor bearing cells in lip biopsy specimens is maintained in Sjögren's syndrome (mean 1.5%), and thus it seems unlikely that these lymphocytes bearing the gamma/delta T cell receptor have a major role in the immunopathology of Sjögren's syndrome. Over 70% of cells within the lesional infiltrate of primary and secondary Sjögren's syndrome expressed the CD5 and CD45 cell surface molecules.

Antigens, CD↗
PubMed1991

A light & electron microscopic study on apoptotic bodies in acute aflatoxin B1 induced injury in the rat liver.

A subnecrogenic dose of aflatoxin B1 (AFB1) was injected intraperitoneally into 8-10 wk old male rats of the Holzman strain. Cytoplasmic and sinusoidal eosinophilic bodies were seen in the liver which appeared at 30 h and reached a maximum at 48 h. Electron microscopically some of the cytoplasmic structures were seen to be of mitochondrial origin whereas others resembled apoptotic bodies. The sinusoidal bodies were similar to apoptotic bodies.

Aflatoxin B1↗
PubMed1991

Histochemical pattern in alimentary tract duplications of children.

Detailed histological and histochemical studies using PAS, AB-PAS, and high-iron diamine-AB were done on 12 alimentary tract duplication cysts in children. Nine of these were thoracic and three were abdominal in location. A total of 11 cysts (nine thoracic and two abdominal cysts) were lined by gastric mucosa seen in varying stages of maturation. One triloculated cyst had, in addition, small intestinal mucosa and bronchial wall mucosa. One intra-mucosal rectal cyst was lined exclusively with primitive rectal mucosa. The cysts showed a variable pattern of mucin histochemistry. In three cysts, the gastric mucosa showed neutral mucins. In another three cysts, in addition to neutral mucins, focal positivity for sulphomucins was observed in the apical region of the surface epithelial cells. In the remaining five cysts, the gastric mucosa showed neutral mucins along with a variable mixture of sulpho- and sialomucins. A correlation was seen between mucin histochemistry and the age of the patient. Neutral mucins or focal positivity for sulphomucins was seen in patients aged 7 months or more, whereas a mixture of sulpho-, sialo-, and neutral mucins was identified in patients who were 1 month old, or less.

Abdomen↗
PubMed1990

Pneumadin: a new lung peptide which triggers antidiuresis.

Normal mammalian lungs, including human fetal lungs, contain significant amounts of a decapeptide which releases arginine-vasopressin from the neurophypophysis and therefore has antidiuretic activity. The rat peptide is: Tyr-Gly-Glu-Pro-Lys-Leu-Asp-Ala-Gly-Val-NH2. The peptide from human fetal lungs has Ala instead of Tyr. It may be a normal regulatory substance and its role in the pathogenesis of the syndrome of inappropriate antidiuresis associated with lung diseases merits investigation. In view of its source and action, the antidiuretic lung peptide may be called Pneumadin.

Amino Acid Sequence↗
PubMed1990

Primary causes of neonatal deaths in a tertiary care hospital in Delhi: an autopsy study of 331 cases.

Of a total of 755 neonates who died between 1972 and 1988, 331 (43.9%) were subjected to necropsy examination. The ranking of major primary causes of neonatal death was as follows: infections 27.2%, hyaline membrane disease 20.2%, congenital malformations 19.6%, perinatal anoxia 14.5%, immaturity 5.1% and birth trauma 2.7%. Over the years, the prevalence of infections as the cause of death has consistently declined. Compared with that in other contemporary Indian studies, the prevalence of hyaline membrane disease is higher and that of infections and perinatal anoxia relatively lower.

Asphyxia Neonatorum↗
PubMed1990

Benign nerve sheath tumors: a light microscopic, electron microscopic and immunohistochemical study of 102 cases.

One hundred and two cases of benign nerve sheath tumors (NSTs) were studied with a combined approach using routine light microscopy (LM), immunohistochemistry (IH) for myelin basic protein (MBP) and S-100 protein as well as transmission electron microscopy (TEM) with the aim of obtaining greater insight into the true nature of these neoplasms, and also to establish the importance of IH and TEM in their diagnosis. Myelin basic protein was not identified in any of these tumors, whereas S-100 protein was positive to a variable degree in both schwannomas and neurofibromas. TEM revealed that Schwann cells predominated in tumors which were strongly positive for S-100 protein and appeared as schwannomas by LM. However, neurofibromas showing a variable patchy positivity for S-100 were composed of an admixture of Schwann cells, fibroblast-like cells and intermediate cells considered to be modified Schwann cells. Perineurial cells in typical form were not seen. It is concluded that all NSTs are basically of Schwann cell origin and that the intermediate cells and fibroblast-like cells are variants of Schwann cells. The different morphological appearances and biological behaviour of schwannomas and neurofibromas may be related to some other factors like micro-environment or genetic predisposition. Further, both IH, especially for S-100 protein, and TEM play an important role in establishing their diagnosis.

Cranial Nerve Neoplasms↗
PubMed1990

Phycomycosis infection in acute leukaemia.

Fungal infections are increasingly being reported in patients with acute leukaemia on intensive induction chemotherapy protocols. The common fungi seen are candida, aspergillus and mucormycosis. We have seen 3 cases of mucormycosis over the last 4 years. All 3 patients had acute leukaemia-two had acute lymphoblastic and one acute myeloid leukaemia. All patients were in neutropenic phase after induction chemotherapy. Features suggestive of fungal infection were fever and development or progression of pulmonary infiltrates despite antibiotic therapy. Repeated body fluid cultures were negative in two patients. In the first patient, the diagnosis was confirmed after biopsy of a palatal mass; he was treated successfully with amphotericin-B. In two patients the diagnosis was confirmed at autopsy. A high degree of suspicion in febrile, neutropenic cancer patients on chemotherapy and early administration of amphotericin-B may improve the outcome. With dissemination, the prognosis is poor.

Adolescent↗
PubMed1990

Incidence of R-plasmids in toxigenic & non-toxigenic strains of Escherichia coli from children with diarrhoea.

Toxigenic (30) and non-toxigenic (30) multiresistant strains of Esch. coli were studied for the incidence of R-plasmids. ST+, LT+ and ST+ LT+ plasmids were produced by 66.7, 30 and 3.3 per cent of toxigenic strains, respectively. ACST was the predominant resistance pattern in both the types. Incidence of R-plasmid in the toxigenic strains was 73.3 per cent as compared to 60 per cent in the non-toxigenic strains. Non-conjugative R-plasmid was present in 10 per cent of the non-toxigenic strain. In 13.3 per cent of toxigenic Esch. coli strains along with the transfer of antibiotic resistance, the ability to produce enterotoxin was also conferred on the recipient. This suggests that the genes coding for antibiotic resistance and enterotoxin are frequently associated and can be transferred together in vitro.

Child, Preschool↗
PubMed1990

Intestinal glucoamylase & other disaccharidases in children with protracted diarrhoea.

Brush border lactase, sucrase and glucoamylase activities were assessed in jejunal mucosal biopsy specimens from 34 children (median age 11 months; range 1.5-38) having protracted diarrhoea with failure to thrive and 8 well nourished children with normal jejunal mucosal histology (median age 10.2 months; range 2-37). All enzymes showed progressive decrease in activity which was directly in relation to increasing degree of mucosal injury (P less than 0.002). Lactase was significantly reduced even in patients with protracted diarrhoea and normal mucosa (P less than 0.05). Glucoamylase and sucrase were significantly reduced only in the presence of mucosal injury (P less than 0.01). Our data suggest that most children with protracted diarrhoea may not tolerate lactose containing feeds and may need lactose-free diets preferably based on starch. A small number of children with protracted diarrhoea, who have severe mucosal injury may not be able to handle even starch and may require diets based on short chain glucose polymers. The findings of this study, need to be corroborated with well-controlled metabolic balance studies.

Child, Preschool↗