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Biomedical subjects

A Saxena

Publications and source records attributed to A Saxena.

At least 271 records · Page 15Linked to original sources
PubMed1989

Intracranial aneurysms in India--microsurgical approach.

This is a retrospective study of 100 cases of intracranial aneurysms, treated in an Indian hospital, reflecting the special situation and experiences in our country. The incidence of subarachnoid haemorrhage due to ruptured aneurysm has been more or less the same as is reported from other parts of the world. The cases of recurrent haemorrhage resulting in poor clinical status are more common in our situation. Delayed referral and diagnosis were responsible for recurrent haemorrhage, increased morbidity and mortality. Forty two percent developed cerebral vasospasm within two weeks after the bleed. The use of a temporary clip on the parent vessel prevented the intraoperative rupture of the aneurysm while dissecting round about the aneurysm. Operative mortality was eight percent in the present series.

Humans↗
PubMed1989

Comparative Doppler evaluation of the monostrut and older convexo-concave Björk-Shiley mitral prosthetic valve.

Doppler echocardiography was performed in 104 patients with a Björk-Shiley prosthetic valve in the mitral position. Valves of size 25 mm and 27 mm were inserted in 39 and 65 patients, respectively. Each valve had two models; the older convexo-concave model (22 and 40, of 25 and 27 mm size, respectively). Inflow velocities were recorded using Doppler techniques and the gradients calculated using the Bernoulli principle. The area of the mitral valve was determined by the T1/2 method. Comparison of the two models for both sizes did not reveal any significant differences in either the gradients across the valves or the area of the valve. Trivial mitral regurgitation was detected in a higher percentage of monostrut valves (18% and 20% for the 25 and 27 mm older convexo-concave models and 59.9% and 52% for the 25 and 27 mm monostrut valve). We conclude that the newer monostrut model of the Björk-Shiley valve in the mitral position does not offer any additional haemodynamic benefit.

Adolescent↗
PubMed1989

Ethylene biosynthesis-inducing protein from cellulysin is an endoxylanase.

The proteinaceous ethylene biosynthesis-inducing factor (EIF) that was purified from Cellulysin was also shown to contain a xylanase activity. In all nondenaturing protein separation methods employed (Sephacryl S-200 chromatography, and preparative isoelectric focusing and agarose electrophoresis), xylanase activity copurified with the ethylene biosynthesis-inducing activity. Treatment with heat (60 degrees C) or proteases in 8 molar urea inhibited both ethylene-inducing and xylanase activities. Antibodies raised against purified EIF, which contains three polypeptides of 18, 14, and 10 kilodaltons, immunoprecipitated both ethylene biosynthesis-inducing and xylanase activities. The purified EIF contained no detectable cellulase, polygalacturonase, or protease activity. Other hydrolytic activities as estimated by using p-nitrophenyl derivatives of several sugars as substrates also were not detected. Different commercially available hydrolytic enzyme preparations were tested for both ethylene biosynthesis-inducing and xylanase activities. All enzymes tested contained xylanase activity, but only a few induced ethylene biosynthesis. Western blots of proteins separated by SDS-PAGE, using antibodies prepared against the non-denatured purified EIF, revealed two major bands of about 18 and 14 kilodaltons in EIF. These antibodies seem to be specific for these proteins from Trichoderma viride, because there was little cross-reactivity with the other proteins in Cellulysin and other commercial enzyme preparations. Based on these data, we suggest that EIF contains a specific xylanase activity which is involved in inducing ethylene biosynthesis.

Journal Article↗
PubMed1989

Analysis of mannans of two relatively avirulent mutant strains of Candida albicans.

We previously reported the isolation of two cerulenin-resistant mutant strains of Candida albicans 4918 that differ in adherence properties and are less virulent than the parental strain. In addition, biochemical characterization demonstrated significant differences in both protein and polysaccharide composition of cell wall material between the mutant and wild-type strains. These observations prompted studies concerning the chemical structure of mannans in these strains. After extraction and subsequent purification by ion-exchange chromatography, mannan fractions were subjected to either mild acid hydrolysis, alkali hydrolysis, or acetylation followed by acetolysis. Acid- and alkali-modified mannans were studied by proton magnetic resonance spectroscopy, and released products were analyzed by high-performance liquid chromatography on an Aminex HPX-42A column. The results demonstrated quantitative and qualitative differences between mannooligosaccharides of the wild-type and mutant strains in the identity of released oligosaccharides as well as in linkage of the oligosaccharides to the protein backbone.

Acetylation↗
PubMed1989

Echocardiographic assessment of infants born to diabetic mothers.

Echocardiography was carried out in 31 neonates (group 1) born to diabetic mothers and 37 control infants (group 2) matched for weight and gestational age. The interventricular septum was significantly thicker in group 1 babies (mean (SD) 4.77 (1.4) mm) compared with those in group 2 (2.5 (0.7) mm); in eight it was more than 5 mm, but had regressed in six over a period of three months. There was no significant difference between the two groups in the left ventricular internal dimension, right ventricular outflow tract, or size of the left atrium or the aorta. The left ventricular mass was significantly greater in infants born to diabetic mothers. The left ventricular contractility (judged by the percentage of shortening of the internal dimension and the ejection fraction) was significantly greater in group 1. No evidence of left ventricular outflow obstruction was found on pulse Doppler echocardiography in group 1.

Cardiomyopathy, Hypertrophic↗
PubMed1989

Bronchogenic carcinoma. A study of 109 cases.

The clinical profile of 109 cases of bronchogenic carcinoma has been studied. Definite histopathological typing of malignancy was possible in 61 patients, squamous cell carcinoma being the commonest tumour in 27 followed by small cell carcinoma in 16, adenocarcinoma in 11 and large cell carcinoma in 7. Another 23 patients showed changes suggestive of malignancy on histological/cytological examination. Definitive diagnosis was obtained in half of the patients by bronchial biopsy, in 16% by bronchial aspiration fluid cytology, in 13% by pleural biopsy, in 11% by lymph node biopsy and in others by pleural fluid cytology, lung biopsy and skin biopsy. Commonest radiological involvement among different cell types was hilar involvement in small cell carcinoma in 62%, evidence of bronchial obstruction (collapse/consolidation) in squamous cell carcinoma in 56%, peripheral mass in adenocarcinoma in 54% and cavitation in a mass in squamous cell carcinoma in 15% cases.

Adenocarcinoma↗
PubMed1988

Myocardial involvement and its response to immunosuppressive therapy in nonspecific aortoarteritis (Takayasu's disease)--a study by endomyocardial biopsy.

Myocardial involvement in nonspecific aortoarteritis was evaluated in 16 patients (age 7-37 years, 2 males, 14 females) with the help of endomyocardial biopsy obtained from the right ventricle using the Cordis bioptome introduced from the right femoral vein. Morphological features of myocarditis were present in 8, endocardial thickening in 2, mild to moderate myofibre hypertrophy in 11, and a normal biopsy in 3 patients. Myocarditis was present in 8/11 cases with active disease and in none with inactive disease. Five of the 8 patients with myocarditis presented with congestive cardiac failure with 3 of them having no associated hypertension or valvar involvement to account for it. Immunosuppressive therapy was given to all patients with myocarditis. Serial studies (ongoing) showed clinical, haemodynamic and morphological improvement. Myocarditis appears to occur commonly in nonspecific aortoarteritis during the acute phase of the disease and may precipitate congestive cardiac failure in some patients. Immunosuppressive therapy shows promise and merits further evaluation.

Adolescent↗
PubMed1988

Metabolism of the 18O-methoxy substituent of 3-methoxybenzoic acid and other unlabeled methoxybenzoic acids by anaerobic bacteria.

O-methyl substituents of aromatic compounds can provide C1 growth substrates for facultative and strict anaerobic bacteria isolated from diverse environments. The mechanism of the bioconversion of methoxylated benzoic acids to the hydroxylated derivatives was investigated with a model substrate and cultures of one anaerobic consortium, eight strict anaerobic bacteria, and one facultative anaerobic microorganism. Using high-pressure liquid chromatography and gas chromatography-mass spectral analysis, we found that a haloaromatic dehalogenating consortium, a dehalogenating isolate from that consortium, Eubacterium limosum, and a strain of Acetobacterium woodii metabolized 3-[methoxy-18O]methoxybenzoic acid (3-anisic acid) to 3-[hydroxy-18O]hydroxybenzoic acid stoichiometrically at rates of 1.5, 3.2, 52.4, and 36.7 nmol/min per mg of protein, respectively. A different strain of Acetobacterium and strains of Syntrophococcus, Clostridium, Desulfotomaculum, Enterobacter, and an anaerobic bacterium, strain TH-001, were unable to transform this compound. The O-demethylating ability of E. limosum was induced only with appropriate methoxylated benzoates but not with D-glucose, lactate, isoleucine, or methanol. Cross-acclimation and growth experiments with E. limosum showed a rate of metabolism that was an order of magnitude slower and showed no growth with either 4-methoxysalicylic acid (2-hydroxy-4-methoxybenzoic acid) or 4-anisic acid (4-methoxybenzoic acid) when adapted to 3-anisic acid. However, A. woodii NZva-16 showed slower rates and no growth with 3- or 4-methoxysalicylic acid when adapted to 3-anisic acid in similar experiments. The results clearly indicate a methyl rather than methoxy group removal mechanism for such reactions.

Acetobacter↗
PubMed1988

Footwear and ankle stability in the basketball player.

Ankle stability in basketball players is affected by footwear. Athletic shoe manufacturers have introduced specialized lacing systems and high-top performance shoes to improve ankle stability. These performance shoes not only aid in preventing ankle injuries, but also protect injured ankles.

Ankle Injuries↗
PubMed1987

Low susceptibility of trophozoites of virulent Entamoeba histolytica to cellular and antibody-dependent cellular cytotoxicity by guinea-pig effector cells.

Cytotoxic potentialities of lymphocytes and macrophages were determined against trophozoites of virulent and avirulent sublines of Entamoeba histolytica in vitro. Guinea-pigs were immunized with antigens of both sublines to obtain stimulated effector cells and antiamoebic antibodies. Trophozoites of an avirulent/attenuated subline of E. histolytica (NIH200) were significantly more susceptible to killing by lymphocytes and macrophages through cellular and antibody-dependent cellular cytotoxic mechanisms. The resistance of virulent trophozoites to killing was attributed to their higher phagocytic ability and virulence characteristics. Electron microscopic studies of the interactions showed that contact between the effector cells and the trophozoites was essential for the cytolytic event which resulted in disintegration of the trophozoites. Antigens of trophozoites of the virulence subline of E. histolytica (NIH200 V) were effective in inducing cytotoxicity against both virulent and avirulent trophozoites: however, the reverse was not true.

Animals↗