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Biomedical subjects

N Malik

Publications and source records attributed to N Malik.

At least 91 records · Page 5Linked to original sources
PubMed1990

Ultrasonographic localization for renal biopsy.

One hundred and fifty consecutive percutaneous renal biopsies were performed using ultrasonography to localise the site and depth of the lower pole of the left kidney. Renal tissue was obtained in 95% of cases and an accurate histopathological diagnosis was reached in 89% of patients. Gross haematuria following the procedure occurred in 6%, but was usually transient. No other complications were encountered. Ultrasonographic marking of the biopsy site and depth is a quick, simple, accurate and safe method of localizing the kidney for the purpose of a biopsy.

Biopsy↗
PubMed1990

Ultrasound in obstructive jaundice.

One hundred and twenty-five consecutive patients with obstructive jaundice were prospectively studied by ultrasonography to determine the level and cause of obstruction. These were diagnosed precisely in 80 (72%) and 52 patients (41.6%) respectively. The results were compared with cholangiography. The final diagnosis was established at surgery (97 cases) and fine needle aspiration cytology (28 cases). While US is an excellent screening modality in distinguishing obstructive and non-obstructive jaundice, cholangiography is still the gold standard for determining the precise anatomic level and cause of obstruction.

Adult↗
PubMed1989

Identification and characterization of cellular receptors for the growth regulator, oncostatin M.

Oncostatin M is a polypeptide growth regulator produced by activated T cells and phorbol ester-treated U937 cells. To identify specific cellular receptors for this factor, we have characterized the binding of 125I-labeled oncostatin M to a variety of normal and malignant mammalian cells. Recombinant oncostatin M was labeled with 125I with full retention of growth inhibitory activity on A375 melanoma cells. 125I-Oncostatin M bound to sensitive cells in a time- and temperature-dependent fashion. Binding was specifically inhibited by unlabeled native or recombinant oncostatin M, but not by other polypeptide growth factors tested. Binding to human leukemic and normal blood cells was generally less than to nonhematopoietic cells. With four different cell lines, maximal growth inhibition by oncostatin M was achieved at less than maximal binding site occupancy. Scatchard graphs of direct binding data were curvilinear and indicated that 125I-oncostatin M bound with higher apparent affinity at lower 125I-oncostatin M concentrations. Using a two binding site model, affinity constants of Kd1 = 11 +/- 11 pM and Kd2 = 1000 +/- 380 pM were extrapolated from binding data with A375 cells, and values of Kd1 = 3 +/- 2 pM and Kd2 = 400 +/- 44 pM from A549 cells. The major 125I-oncostatin M binding species in a number of mammalian cell lines was identified by chemical cross-linking as a specific protein(s) of Mr = 150,000-160,000. 125I-Oncostatin M was internalized (t1/2 = 30 min) and degraded subsequent to binding to a responsive cell line.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Penile venous haemangioma.

A case of venous haemangioma at the base of penis is reported. The patient presented with complaints of pain, hemilateral tilting during erection and progressively increasing swelling at the base of penis. The lesion was resected surgically and was diagnosed on histopathological examination to be penile venous haemangioma. Possible aetiopathogenesis of haemangioma in general and characteristics of venous haemangioma in particular are briefly discussed. A similar case report has not been found in the literature.

Adult↗
PubMed1989

Molecular cloning, sequence analysis, and functional expression of a novel growth regulator, oncostatin M.

Oncostatin M is a polypeptide of Mr approximately 28,000 that acts as a growth regulator for many cultured mammalian cells. We report the cDNA and genomic cloning, sequence analysis, and functional expression in heterologous cells of oncostatin M. cDNA clones were isolated from mRNA of U937 cells that had been induced to differentiate into macrophagelike cells by treatment with phorbol 12-myristate 13-acetate, and a genomic clone was also isolated from human brain DNA. Sequence analysis of these clones established the 1,814-base-pair cDNA sequence as well as exon boundaries. This sequence predicted that oncostatin M is synthesized as a 252-amino-acid polypeptide, with a 25-residue hydrophobic sequence resembling a signal peptide at the N terminus. The predicted oncostatin M amino acid sequence shared no homology with other known proteins, but the sequence of the 3' noncoding region of the cDNA contained an A + T-rich stretch with sequence motifs found in the 3' untranslated regions of many cytokine and lymphokine cDNAs. Oncostatin M mRNA of approximately 2 kilobase pairs was detected in phorbol 12-myristate 13-acetate-treated U937 cells and in activated human T cells. Transfection of cDNA encoding the oncostatin M precursor into COS cells resulted in the secretion of proteins with the structural and functional properties of oncostatin M. The unique amino acid sequence, expression by lymphoid cells, and growth-regulatory activities of oncostatin M suggest that it is a novel cytokine.

Amino Acid Sequence↗
PubMed1989

Postpyelolithotomy renal artery pseudo-aneurysm.

A case of pseudo-aneurysm arising from the posterior division of right renal artery following pyelolithotomy is presented. The patient presented with massive haematuria and flank mass 7 days after pyelolithotomy. Selective renal arteriography revealed large pseudo-aneurysm in relation to the posterior division of renal artery. Nephrectomy was necessitated to control the bleeding. The relevant literature is reviewed.

Adult↗
PubMed1989

Cholangiographically guided aspiration cytology in the management of malignant biliary obstruction.

Fifteen patients with malignant biliary obstruction were subjected to fine needle aspiration cytology (FNAC) under fluoroscopic guidance. Fourteen (93%) of them were correctly diagnosed to have a malignancy at FNAC. Simultaneous with FNAC or at a later date, all the patients underwent percutaneous biliary drainage with a drop in serum bilirubin from a mean of 23.2 mg/dl to 8.5 mg/dl. Ten patients were subjected to exploratory laparotomy and biopsy at which the diagnosis of FNAC was confirmed in nine of them. The tenth patient with a negative yield at FNAC had a 1.0 cm cholangiocarcinoma. The usefulness of FNAC combined with biliary drainage as an alternative to surgery is highlighted.

Adenoma, Bile Duct↗
PubMed1988

Taurine depletion leads to loss of rat optic nerve axons.

The number of axons in the optic nerve have been examined in rat pups raised by control or taurine-depleted mothers, at 21, 28 and 40 days after birth. Optic nerves from the mother rats were also studied. Taurine depletion of dams and some litters after weaning was achieved by in vivo treatment with guanidinoethyl sulfonate, an inhibitor of taurine transport. Retinal taurine content was reduced by this procedure and reductions in axon density (axons per area) were found in some groups. Comparison of axon densities obtained from light or electron micrographs suggested that taurine-deficient pups might have a higher proportion of small diameter fibres than controls, perhaps due to slowed growth and/or myelination. Reductions in the calculated total number of optic nerve fibres attained statistical significance consistently only in the treated dams. Ganglion cell degeneration may be direct or secondary to effects on taurine-sensitive elements at more distal retinal sites.

Animals↗
PubMed1988

Benign periurethral mass lesions: the female prostate.

Bladder outflow obstruction in the female is usually a functional complaint, but rarely may be of organic aetiology, due to peri-urethral mass lesions. These lesions are usually midline in location and present clinical and roentgenological features comparable with those of prostate in the male. Two such patients, one of pure fibroma and another of hyperplastic glandular tissue are presented and their management is discussed.

Female↗
PubMed1987

Retinal morphology in rats treated with a taurine transport antagonist.

Previous studies have shown that chronic treatment of rats with guanidinoethyl sulfonate (GES), an antagonist of taurine uptake, leads to depletion of retinal taurine content and electroretinogram abnormalities. In this study we examined with the light- and electron microscope the retina and pigment epithelium of mother rats treated for 8 weeks with 1% GES in their drinking water. Pigment epithelial cells appeared swollen, sometimes with mitochondrial vacuolization and loss of cytoplasmic density, and changes in nuclear shape and chromatin distribution. Photoreceptor cells had shorter outer segments with disarray of disks, swollen inner segments and nuclei, and loss of synaptic terminal contents. These degenerative changes frequently led to cell death, indicated by loss of photoreceptor cell nuclei and shrinkage of the outer nuclear layer, and disappearance of photoreceptor synaptic terminals from the outer plexiform layer. Narrowing of the outer plexiform layer was due also to the retraction of cell processes from higher-order neurons. Quantitative studies of the retina along the vertical meridian passing through the optic nerve head showed that treatment resulted in significant reductions in the number of rod-cell nuclei per field, the width of the outer nuclear layer, and the width of the inner retina. Effects were more pronounced in the superior than the inferior hemisphere, reminiscent of findings in light-damage studies. A possible role for taurine in the cellular defence mechanisms against light- and oxygen-induced damage is suggested.

Animals↗
PubMed1987

Bovine and human cDNA sequences encoding a putative benzodiazepine receptor ligand.

cDNAs containing the entire coding sequence of endozepine, a putative ligand of the benzodiazepine receptor, were isolated from bovine and human cDNA libraries. These libraries were constructed using a novel oligonucleotide adapter molecule that allowed us to combine the use of G/C tailing with the preservation of the unique Eco RI site in the vector, lambda gt10. The amino acid sequences derived from these cDNA clones are identical to those previously determined for the purified proteins and are homologous to a related rat protein termed diazepam-binding inhibitor. The endozepine proteins are highly conserved, as illustrated by the finding that the nucleotide sequences of the coding regions are 93% conserved between the bovine and human forms. Analysis of these sequences indicates that endozepine is not, as expected, derived from a precursor molecule containing a transient signal peptide. Moreover, Northern analyses using the cloned cDNAs as hybridization probes indicate that the 650-nucleotide endozepine mRNA is expressed in a number of peripheral tissues in addition to brain. These observations may be consistent with a recent report describing the presence in peripheral tissues of benzodiazepine receptors on the outer mitochondrial membrane (Anholt et al., 1986). In addition to the endozepine cDNAs, we also isolated a bovine cDNA clone which encodes a larger protein, a portion of which is homologous to endozepine. This related protein may be synthesized in a precursor form containing putative signal peptide and membrane-spanning domains.

Amino Acid Sequence↗
PubMed1987

ICMSF methods study. XVII. An international comparative study of the direct plate and hydrophobic grid-membrane filter methods for enumeration of Escherichia coli in foods. International Commission on Microbiological Specifications for Foods.

Eight laboratories compared counts of Escherichia coli from naturally or artificially contaminated ground beef, other meats and poultry, vegetables, fish and shellfish, cheese, and diverse sources such as swabs, by the Anderson-Baird-Parker direct plate (DP) and a hydrophobic grid-membrane filter (HGMF) method. For five of the eight laboratories overall counts by HGMF were significantly low (51-83%) compared with those by DP. Counts by HGMF tended to be lower for naturally contaminated samples; several possible causes were investigated. In a subsidiary study, analyst variation in counting HGMF ranged from 0.8-7.3%, with little evidence of effects from counting positive versus negative grid cells or from the fullness of growth or staining intensity.

Bacteriological Techniques↗
PubMed1986

Intrarenal gas abscess.

Intrarenal abscess owing to gas-forming gram-negative bacteria is rare. Female patients and diabetics, or those with urinary calculi or obstructive uropathic conditions commonly are affected. We report on a nondiabetic man who was infected with Pseudomonas aeruginosa. Initial medical management and subsequent partial nephrectomy offered cure.

Abscess↗