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Biomedical subjects

M Khan

Publications and source records attributed to M Khan.

At least 235 records · Page 13Linked to original sources
PubMed1989

Angiotensin II binding to human mononuclear cells.

Serum angiotensin converting enzyme activity is elevated in certain human granulomatous diseases. Angiotensin II modestly suppresses thymidine incorporation and augments gamma interferon production from human blood mononuclear cells. This suggests that angiotensin II may play an immunoregulatory role in human granulomatous inflammation. For this reason, the binding of angiotensin II to human peripheral blood mixed mononuclear cells, and to the human monocyte-like cell line, U-937, was studied. Angiotensin II binding to U-937 cells reveals a low level of saturable specific binding (Kd = 3 x 10(-10) M). However, binding to human cells is not easily reversible and is poorly inhibited in a competitive manner. In addition, the molecular integrity of the radioligand is not maintained following binding. Therefore, the definition of classical receptor binding cannot be fulfilled. Since binding is decreased by low temperatures and various metabolic inhibitors, it appears likely that endocytosis occurs, perhaps along with receptor binding. Angiotensin II or its breakdown products modulate the production of monocyte cAMP in spite of the inability to demonstrate classical cell surface receptors.

Angiotensin II↗
PubMed1989

Prospective study of 111 cases of thyroid surgery for post-operative morbidity and mortality.

One hundred and eleven patients were operated for various types of goitre between December, 1985 to June, 1988. These were evaluated to assess the morbidity and mortality associated with thyroid operations. A mortality of 0.9% was noted, owing to advanced age and fatal laryngeal oedema. Recurrent laryngeal nerve damage was seen in one (0.90%) case. Transient Parathyroid insufficiency appeared in 8.10% cases while the permanent damage occurred in one (0.9%) case only. Wound complications, including haematoma formation were noted in 14.40% cases. This study indicates that the thyroid surgery can be performed with acceptable morbidity and mortality, under the prevailing circumstances.

Adolescent↗
PubMed1989

Electrohemostasis with endoscopic electrocoagulation in upper gastrointestinal bleed.

Fifty patients who presented with upper gastrointestinal bleed were taken up for electrohemostasis with endoscopic electrocoagulation. Hemostasis was achieved in 32 patients at the first sitting, and in a second session in two of eight patients in whom it was attempted. No complications were encountered. EEC is an effective and safe method of achieving hemostasis in upper gastrointestinal bleed due to varied gastroduodenal lesions, and may help cut down the number of patients subjected to emergency surgery.

Adolescent↗
PubMed1989

Biliary ascariasis.

The clinical presentation of 12 cases with biliary ascariasis is reported. Ultrasonography was employed to demonstrate worms in the gallbladder and common bile duct preoperatively. Ten cases were operated upon and operative findings were compared to assess the accuracy of sonography in biliary ascariasis. Our results show that ultrasonography can be relied upon for the demonstration of biliary tract ascariasis.

Adolescent↗
PubMed1988

[Experimental study of the effect of raw materials of the neem tree and neem extracts on dermatophytes, yeasts and molds].

In traditional Indian medicine, various parts of the neem tree have been used for centuries, especially with skin diseases. These products are often applied in human mycoses. We tested some dried neem materials, neem oils as well as simple neem preparations and extracts with regard to their effect on 14 of the most common pathogenic fungi. Neither the dried neem materials nor the medical preparations and oils had any effect on fungal growth; most of them were even contaminated with molds. Some of the extracts, however, showed antimycotic properties, which decreased with rising solvent polarity. Petrolether leaf extract proved most effective. One of the possible explanations might be the fact that it contains quercetin, a flavonoid.

Dermatomycoses↗
PubMed1988

Bronchoalveolar lavage in talc induced lung disease.

A 65 year old woman with a history of occupational talc inhalation presented with hypoxaemia, cough, and dyspnoea with a normal chest radiograph. Bronchoalveolar lavage showed considerable lymphocytosis, with a predominance of T8+ T lymphocytes, and open lung biopsy showed peribronchiolar granulomas containing talc crystals. Corticosteroid treatment resulted in dramatic improvement. Bronchoalveolar lavage may aid in the diagnosis of talc related lung injury.

Aged↗
PubMed1987

The four stereoisomers of a high potency congener of isoproterenol. Biological activity and the relationship between the native and the chemically inserted asymmetric carbon.

The RR isomer of a para-trifluoromethyl anilide congener of isoproterenol (PTFMA) had an affinity eighty and one hundred times higher than (-)isoproterenol for the beta receptor of turkey erythrocytes and of S49 cells respectively. This affinity was also much higher than that of +/- hydroxybenzyl isoproterenol (HBI) tested in the same experiments. The chemically inserted asymmetric carbon seemed to be as important as the native asymmetric carbon of the catecholamines in determining the binding affinity. Thus the RS and SR isomers demonstrated similar affinities in the turkey erythrocyte membranes as well as in the S49 lysed cells. The RR isomer had the lowest Kact in activation of adenylate cyclase in both beta receptor systems. The three most potent PTFMA isomers showed a Kact/Kd ratio which was higher than that of (-)isoproterenol or (+/-)HBI. It is therefore possible that the large substituent on the amino group in PTFMA, which greatly increases the binding affinity, is not as efficient in receptor activation. Yet the RR isomer had a Kact considerably lower than that of (-)isoproterenol in both of the beta receptor systems. The type of beta receptor of the turkey erythrocyte could be distinguished from that of the S49 cells by comparing the relative order of affinities of the RS and SR isomers and also by comparing (+/-)HBI with (-)isoproterenol. A labeled RR isomer of PTFMA could become most useful as an agonist ligand for beta receptors because of its very high binding affinity for both beta 1 and beta 2 receptors.

Adenylyl Cyclases↗
PubMed1987

Determination of pharmacokinetics of cocaine in sheep by liquid chromatography.

Cocaine was administered as 1-, 2-, and 4-mg/kg intravenous bolus doses to each of six sheep. Plasma samples were collected as a function of time and assayed for cocaine using reversed-phase ion-pair HPLC. The assay involved double extraction with ether and UV detection at 229 nm. Using 2 mL of plasma, levels of 1 ng/mL of cocaine can be measured. The concentration versus time data obtained for the plasma samples were analyzed by a "noncompartmental" method. The pharmacokinetic parameters of cocaine in sheep had mean values of 4.0 L/kg, 3.5 L/kg, and 0.29 L X min-1 X kg-1 for Vd, Vdss, and CL respectively. The clearance of cocaine in sheep was much higher than cardiac output. Pulmonary first-pass effect has been suggested as the possible explanation for the large clearance of cocaine in sheep.

Animals↗
PubMed1987

A model for ultrafilterable plasma platinum disposition in patients treated with cisplatin.

A model incorporating recent information regarding the specificity of a high-performance liquid chromatographic assay for "active" platinum in plasma ultrafiltrate, and the concept of mobile and fixed metabolites, was developed for cancer patients treated with cisplatin. Model parameters were determined using plasma and urinary platinum data obtained in 20 patients. It was assumed in the model that parent drug accounted for essentially all the platinum measured in plasma ultrafiltrate in the 2 h period immediately post infusion. At times greater than 4 h post infusion, platinum concentrations in plasma ultrafiltrate were assumed to be due entirely to reactive, mobile metabolites with possible cytotoxicity. The model accurately simulated platinum concentrations in plasma ultrafiltrate over a 24-h period following a 2-h infusion of 80 mg/m2 of cisplatin to seven patients, 100 mg/m2 to ten patients and 120 mg/m2 to three patients.

Adult↗
PubMed1987

Purple urine bag syndrome.

Purple pigment extracted from the urinary catheters and collecting bags of two elderly female patients was analysed by a variety of chemical techniques, including mass spectroscopy and nuclear magnetic resonance. Although previous studies identified the pigment as indigo, we failed to confirm this. Our analysis also demonstrated that indicanuria is not a requirement for the production of the pigment and furthermore indicates that the molecular structure of the pigment is either a steroidal or bile acid conjugate.

Aged↗
PubMed1987

Creatinine clearance as a predictor of ultrafilterable platinum disposition in cancer patients treated with cisplatin: relationship between peak ultrafilterable platinum plasma levels and nephrotoxicity.

Ultrafilterable platinum (UP) disposition was studied in 22 cancer patients receiving their first course of cisplatin (50 to 140 mg/m2) by two-hour infusion. UP plasma and urinary platinum levels were quantitated using a high-performance liquid chromatographic (HPLC) assay, which was selective for cisplatin and active platinum metabolites. Creatinine clearance was determined in all patients at the time of the pharmacokinetic studies and ranged from 58 to 214 mL/min. Creatinine clearance was a poor predictor of UP disposition in patients, probably as a consequence of the complex renal clearance mechanism for UP in the human kidney, which involves both tubular secretion and reabsorption. However, the peak plasma level of UP was closely related to the area under curve (AUC) of UP (r2 = .831), P less than .0001) and was significantly correlated with the decline in creatinine clearance observed after four courses of cisplatin therapy to 12 of the patients (r2 = .727, P less than .005). Cisplatin dose and the AUC of UP were less satisfactory predictors of the change in creatinine clearance with four courses of therapy (r2 = .488, P less than .025 and r2 = .623, P less than .005). The large interpatient variability in all the parameters of cisplatin disposition measured in this study suggested that there may be a role for individualization of cisplatin dosage based on a peak level obtained in the first course of therapy. Longer term infusion of cisplatin could also be justified.

Adult↗
PubMed1986

Distinct short-lived and long-lived antibody-producing cell populations.

This report analyzes the life span of Ig-containing cells (IgCC) in different sites of antibody production. The experimental approach was based upon the observations that most IgCC are derived from proliferating precursors while IgCC themselves are mainly nondividing end cells. Rats were given a continuous infusion of [3H] thymidine via an osmotic pump inserted in the peritoneal cavity. At intervals of 1, 3, 5 or 10 days after starting infusions, tissues were taken and analyzed by a combination of immunohistology and autoradiography to identify the proportions of IgCC which had gone through S phase of the cell cycle during the period of infusion. After 3 days infusion the median and (range) percent-labeled IgCC in the medullary cords of mesenteric and cervical lymph nodes and the red pulp of the spleen were, respectively, 88 (81-90), 75 (66-77) and 88 (82-93). Conversely that for IgCC in bone marrow was only 13 (11-17) and that in the lamina propria of the jejunum 47 (33-68). The rate of increase in labeling of bone marrow IgCC with length of infusion was approximately linear. Extrapolation of this slope suggests that bone marrow IgCC have a life span in excess of 3 weeks. The slopes of increase in IgCC labeled with time for lymph nodes and spleen were clearly biphasic suggesting that while most IgCC in these tissues have a life span of less than 3 days, there is also a minor population of long-lived IgCC. The lamina propria appears to have approximately equal proportions of long and short-lived IgCC. The life span of IgCC, with the exception of IgMCC, appears to be a feature of the site of antibody production rather than the Ig class produced. Almost all IgM-containing cells were found to be short lived.

Animals↗
PubMed1986

Effects of potassium chromate on atherosclerosis prevention and regression in rabbits.

The effect of intraperitoneal injections of potassium chromate on prevention and regression of atherosclerosis was observed in New Zealand White rabbits. In rabbits fed a 1% cholesterol diet for 90 days, potassium chromate injection was not associated with a significant difference in weight, serum cholesterol, total cholesterol content per 8.5 cm aorta, cholesterol content per gram of aorta or percent intima covered with plaque compared to controls. Similarly, significant differences were not seen in rabbits fed a 1% cholesterol diet for 90 days followed by 60 days of potassium chromate or distilled water injections and a standard diet. These results are in keeping with recent studies suggesting a more limited role for chromium in a variety of lipid-related disorders.

Animals↗
PubMed1986

An antigenic study of human plasma cells in normal tissue and in myeloma: identification of a novel plasma cell associated antigen.

A mouse monoclonal antibody named BU11 which detects an antigen strongly expressed on human plasma cells is described. The antibody stains plasma cells in tonsil sections, fresh and cultured plasmacytoid cells from the bone marrow of patients with multiple myeloma and cells of the plasmacytoid cell line RPMI 8226 used as the immunogen. In vitro studies of pokeweed mitogen (PWM) stimulated peripheral blood B cells and Epstein-Barr virus (EBV) stimulated tonsil B cells show that the antigen is present mainly on cells coexpressing the OKT10 antigen and containing cytoplasmic immunoglobulin (cIg). The BU11 antigen is expressed weakly on some normal B cells and is not present on T cells, monocytes or granulocytes. The antigen is of molecular weight 58kD under reducing conditions and is biochemically distinct from previously described plasma cell antigens.

Animals↗