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Biomedical subjects

A Malik

Publications and source records attributed to A Malik.

At least 91 records · Page 5Linked to original sources
PubMed1996

A ureteric bud cell line induces nephrogenesis in two steps by two distinct signals.

Nephrons develop from mesenchymal cells that have contacted the ureteric bud (UB). To determine whether cell associated or secreted ureteric molecules induce the mesenchyme, we have isolated UB cell lines from mice transgenic for T antigen. These cells express epithelial and ureteric (Dolichos lectin staining, c-ret, c-met without hepatocyte growth factor) specific markers, which identifies them as authentic UB cells. Medium conditioned by our cells rescues mesenchyme from apoptosis without inducing the appearance of epithelial aggregates. The same was found by culturing mesenchymes upon the apical surface of a UB monolayer. In contrast, tubules were induced in mesenchymes contacting trypsinized pellets of UB cells. As revealed by staining for T antigen and Dolichos lectin or by prelabeling UB cells with 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI), we found that our cells encapsulated the mesenchyme but did not incorporate in the tubules. These data demonstrate that nephrogenesis is stimulated by two distinct ureteric signals, secreted molecules rescue the mesenchyme from apoptosis, whereas diffusion-limited basolateral molecules trigger mesenchymal/epithelial conversion.

Animals↗
PubMed1996

Prognostic evaluation of cell mediated immunity in leprosy and correlation with clinicopathological status of leprosy patients.

Cell mediated immunity was studied in 50 patients of leprosy and 15 control volunteers, by estimation of peripheral blood lymphocytes (PBL), total rosette forming cells (TRFC) and active rosette forming cell (ARFC) counts in vitro. PBL, TRFC and ARFC counts were slightly but not significantly increased in patients of tuberculoid leprosy (TT) and muculoanaesthetic variant of tuberculoid leprosy as compared to control group. However, gradual decrease in T-cell subsets, occurred in borderline tuberculoid leprosy (BT) as compared to tuberculoid type (TT)-(p < 0.05). Significant decrease in lymphocytes and T-cell subsets was observed in midborderline leprosy (BB), (p < 0.01):borderline lepromatous leprosy (BL), (p < 0.001) and lepromatous subpolar and polar types (LL); (p < 0.001) as compared to control group. Mycobacterium leprae (M.leprae) were positive in BT-(20%); BB-(72.7%); BL-(83.2%) and LL-(100%). Delayed hypersensitivity reactions (DHR) revealed significantly increased lepromin positivity in TT (83.3%) and BT (80%) which decreased in BB (63.6%) and BL (50%). Lepromin test showed anergic state in LL group (28.5% positivity). Dinitrochlorobenzene (DNCB) skin test showed 100% positivity in TT group and controls while gradual significant decrease was observed from BT (p < 0.05) to LL scale (p < 0.001). Leprosy spectrum of Ridley and Jopling scale is directly co-related with inherent cell mediated immune status of the patients which has a significant prognostic role in treatment and long term management.

Adolescent↗
PubMed1996

Conduction disturbances in acute myocardial infarction: incidence, site-wise relationship and the influence on in-hospital prognosis.

The study was designed to assess the incidence of conduction disturbances, the relationship of the site of infarction with the type of conduction disturbances and the influence of conduction disturbances on the in-hospital prognosis. One hundred consecutive patients (M:F = 89:11) with a age range of 35-60 years with the history of first attack of acute myocardial infarction were included in the study. There were 45 anterior, 43 inferior and 12 combined anterior and inferior myocardial infarction patients. 44 of the patients had some type of conduction disturbances (Group A) and 56 had none (Group B). Inferior myocardial infarction patients showed higher incidence of conduction disturbances than anterior myocardial infarction (56.8% and 31.8% respectively) (Odd's ratio 2.98, 95% ci 1.14 to 7.9). Conduction disturbances were mostly (92%) atrio-ventricular in inferior myocardial infarction and mostly (72%) intraventricular in anterior myocardial infarction. Of the 13 cases of complete atrioventricular block, 8 had inferior, 2 anterior and 3 combined anterior and inferior infarction. In inferior infarction, complete atrioventricular block developed gradually through 1 degree and 2 degrees atrioventricular block but in the anterior infarction it developed suddenly. Patients with conduction disturbances developed more complications (84%) than those without conduction disturbances (54%). Mortality rate was higher in Group A (25%) than in Group B (3.6%) (Odd's ratio 9.0, 95% ci 1.76 to 86.73) with a overall rate of 13%. Mortality rate was higher in anterior myocardial infarction (50%) than in inferior myocardial infarction (25%) when complicated by complete atrioventricular block. It was concluded that conduction disturbances are predominantly atrioventricular in inferior and intra-ventricular in anterior MI; conduction disturbances are associated with increased risk of complications and death. Anterior location of MI may have an independent risk attribute.

Adult↗
PubMed1995

Mutagenic activity of the Ganges water with special reference to the pesticide pollution in the river between Kachla to Kannauj (U.P.), India.

Water samples from Ganga river were collected from 3 different locations viz. Kachla, Fatehgarh and Kannauj (U.P.). High performance liquid chromatography analysis of samples by liquid-liquid extraction procedure showed the presence of some pesticides like DDT, alpha-BHC, aldrin, dieldrin etc. DDT, alpha-BHC, DDD, aldrin and dieldrin were present at concentration ranges of 3.33-5.33 ppb, 1.73-3.01 ppb, 0.88-2.41 ppb, 1.17-2.81 ppb and 0.49-4.11 ppb, respectively. The organophosphorus pesticides like dimethoate and methyl parathion were also detected at the concentration levels of 0.41-0.56 ppb and 0.16-0.50 ppb, respectively. The organic substances in the test samples were extracted by XAD-resin and liquid-liquid extraction procedures, and the extracts were assayed for mutagenic potential by the Ames Salmonella/microsome test. The test samples exhibited a remarkable degree of mutagenicity with TA98, TA100 and TA97a strains with the probable role of contaminating pesticides in the river water.

Base Composition↗
PubMed1995

Identification of a nonameric H-2Kk-restricted CD8+ cytotoxic T lymphocyte epitope on the Plasmodium falciparum circumsporozoite protein.

Class I-restricted CD8+ cytotoxic T lymphocytes (CTL) against the circumsporozoite protein (CSP) protect mice against the rodent malaria parasite, Plasmodium yoelii, and vaccines designed to produce protective CTL against the P. falciparum CSP (PfCSP) are under development. Humans and B10.BR (H-2k) mice have been shown to have CD8+ CTL activity against a 23-amino-acid region of the PfCSP (residues 368 to 390 from the PfCSP 7G8 sequence) that is too long to bind directly to class I major histocompatibility complex molecules. To identify within this 23-amino-acid peptide a shorter peptide that binds to an H-2k class I major histocompatibility molecule, a primarily CD8+ (97.8%) T-cell line (PfCSP TCL.1) was produced by immunizing B10.BR mice with recombinant vaccinia virus expressing the PfCSP and stimulating in vitro spleen cells from these immunized mice with L cells transfected with the PfCSP gene (LPF cells). PfCSP TCL.1 lysed LPF cells and L cells pulsed with peptide PfCSP 7G8 368-390. When 15 overlapping nonamer peptides spanning the 368 to 390 sequence were tested, only one peptide, PfCSP 7G8 375-383 (Y E N D I E K K I), which includes an H-2Kk-binding motif, E at amino acid residue 2, and I at residue 9, sensitized targets for lysis by PfCSP TCL.1. Furthermore, a 10(3)- to 10(4)-fold lower concentration of the nonamer than that of the 23-amino-acid peptide was required to sensitize target cells for lysis by PfCSP TCL.1. Presentation by H-2Kk was demonstrated by using 3T3 fibroblast cells transfected with the murine H-2Kk or H-2Dk genes, and only the H-2Kk transfectants were lysed by PfCSP TCL.1 after incubation with peptide PfCSP 7G8 375-383. Binding to H-2Kk was confirmed by competitive inhibition of binding of labelled peptides to affinity-purified Kk molecules. Substitution of the anchor amino acid residue, E, at position 2 with A dramatically reduced binding to Kk and eliminated the capacity of the peptide to sensitize target cells for killing. Variation of non-anchor residues did not markedly reduce binding to Kk but in some cases eliminated the capacity of the peptide to sensitize targets for cytolysis by PfCSP TCL.1, presumably by eliminating T-cell receptor-binding sites. These data suggest that similar studies with human T cells will be required for optimal development of peptide-based vaccines designed to produce protective class I-restricted CD8+ CTL against the PfCSP in humans.

3T3 Cells↗
PubMed1995

Morphological and biochemical changes in lenses of guinea pigs after vitamin-C-deficient diet and UV-B radiation.

The effect of ultraviolet B (UV-B) radiation and a vitamin-C-deficient (VCD) diet on guinea pig lenses was investigated. The initial lens changes in the VCD group were observed by slit-lamp examination 6 weeks after the start of the VCD treatment; after 12 weeks the changes in the posterior subcapsular region became more prominent, and the dissociation around the posterior suture became wider and slightly deeper toward the posterior cortex. The high concentration of lens oxidized glutathione (GSSG), and the low ratio of reduced glutathione (GSH) to oxidized glutathione (GSH/GSSG) on the lens posterior region correlated with density changes in the corresponding layers as measured by Scheimpflug images with linear microdensitometry. It is suggested that the strong oxidative stress of the VCD diet caused the damage at the posterior part of the lens. UV-B radiation appeared to accelerate cataract progression in lenses that lack vitamin C.

Animals↗
PubMed1995

A study of nosocomial infection in relation to different host factors in an Indian teaching hospital.

Out of a total of 422 patients studied, 164 (38.8%) developed nosocomial infection. The rate was higher (41.6%) in males than in females (34.7%). A rising trend of infection was observed with age, maximum (69.6%) being in the above 60 age group. Nosocomial infection rate was inversely proportional to the socio-economic status of the patient. At the same time some underlying diseases in the patients influenced the rate of infection to a great extent, eg infection rates in patients with anaemia (53.7%), diabetes mellitus (85.2%), hypertension (82.0%) and obesity (51.5%) were much more than in patients with no such underlying disease (17.5%).

Adolescent↗
PubMed1995

Cardiovascular manifestations in aluminium phosphide poisoning with special reference to echocardiographic changes.

Twenty five patients of aluminium phosphide poisoning along with clinical evidence of peripheral circulatory failure were studied. Chief symptoms noted were vomiting and epigastric pain though subsequently three patients developed respiratory distress. Sensorium was normal in most of the patients. Three patients developed pulmonary edema. Raised JVP, feeble heart sounds and S3 gallop beside tachy and bradycardia were other cardiovascular manifestations observed in these patients. In 80% of the patients, various types of ECG changes were observed. ST-T changes were observed in 40% of the patients. Echo-cardiography on day 1 revealed marked LV systolic dysfunction (mean ejection fraction-43.52 +/- 10.18% and mean fractional shortening 17.35 +/- 4.97%) in them whereas repeat echocardiography on day 5 indicated normalisation of these values (mean ejection fraction 71.64 +/- 8.61% and mean fractional shortening 34.35 +/- 8.23%). This might be because of direct toxic action of phosphine on myocardium and later when phosphine gets excreted either through lungs or kidney leads to improvement in LV systolic function.

Adult↗
PubMed1994

Analysis of nucleotide pools in human lymphoma cells by capillary electrophoresis.

Capillary electrophoresis is applied to determine nucleotide pool levels in human Burkitt lymphoma cells. The analysis was performed on a 65 cm x 50 microns I.D. Ucon-coated column with on-column UV detector. The method requires only nanoliters of sample and a simple sample preparation procedure. Over 12 nucleotides were separated and quantitated with high resolution and reproducibility. The whole capillary electrophoretic separation time was only 35 min. These results demonstrate that capillary electrophoresis provides a useful and easy way to analyze nucleotide pools in cells.

Adenine Nucleotides↗
PubMed1994

A capillary electrophoresis method for studying apo, holo, recombinant, and subunit dissociated ferritins.

A capillary electrophoresis (CE) method is described for detecting and quantitating apo and holo ferritins from horse spleen (HoSF), rat liver (RLF), recombinant human light chain (rLF), recombinant human heavy chain (rHF), site-directed variants of human light chain, and Azotobacter vinelandii bacterial ferritin (AVBF). This procedure is carried out at pH 8.2, where the ferritin molecules are associated into their 24-mers. Protein mobilities as expressed as elution times were clearly resolved and could be used to distinguish one ferritin type from another, providing a means for detecting and quantitating various ferritin species in purified or partially purified states. Measurements of these and other ferritins were also conducted at pH 2.0, where dissociation into their respective subunits occurs. For HoSF and RLF, the individual L and H subunits were resolved and their relative concentrations were determined by integrating the areas of the elution peaks. HoSF gave 89.8% L and 10.2% H and RLF gave 70.7% L and 29.3% H, while rLF, rHF, and AVBF gave only a single subunit, all in agreement with reported values obtained by polyacrylamide gel electrophoresis. CE of HoSF, containing increasing amounts of iron in the interior, in general, showed that protein mobilities increased, reached a plateau, and then slowly decreased with increasing core size, although buffer effects altered this CE behavior to some extent. Such results indicate that species formed early during core formation have individual iron atoms present and differ from those formed later in which the oligomeric iron core has formed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Capillary electrophoresis of nucleotides on ucon-coated fused silica columns.

Ucon-coated columns have been used to isolate nucleotides, such as ribonucleotides, deoxyribonucleotides, and pyridine nucleotides, by capillary zone electrophoresis. This neutral, hydrophilic column coating (Ucon) significantly reduced macromolecule adsorption and electroosmotic flow, which provides the maximum resolution of the nucleotides separated under moderate buffer conditions (pH about 5-6). The relative standard deviations of the nucleotides were less than 1%. Low minimum detectable concentrations (about 2-8 microM) and quantities (about 70-360 fmol) of the ribonucleotides were obtained. A qualitative and quantitative analysis of the ribonucleotides in hybridoma cell extracts shows the applicability of the developed methodology for the determination of intracellular nucleotide pools under the desirable buffer conditions.

Cells, Cultured↗