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Biomedical subjects

A Banerjee

Publications and source records attributed to A Banerjee.

At least 415 records · Page 23Linked to original sources

Purification of a unique glycoprotein that enhances phenol oxidase activity in scorpion (Heterometrus bengalensis) haemolymph.

A monomeric glycoprotein (SGP) of Mr 32,000 was isolated to purity from scorpion (Heterometrus bengalensis) haemolymph by (NH4)2SO4 fractionation, chromatofocusing and h.p.l.c. The homogeneity of SGP is confirmed by polyacrylamide-gel electrophoresis. SGP is soluble in 100%-satd. (NH4)2SO4 solution. Needle-shaped crystals of SGP were obtained in an aqueous environment. The glycan part of the molecule contains arabinose, which does not commonly occur in animal glycoproteins. Amino acid analysis demonstrated a preponderance of glycine, tyrosine and glutamic acid. SGP enhances phenol oxidase (EC 1.14.18.1) activity.

Animals↗

Tuberculous and granulomatous mastitis.

Granulomatous breast diseases are rare and may be indistinguishable clinically from carcinoma. Four cases illustrating the various modes of presentation and diagnostic difficulties are presented. Guidelines for management are suggested.

Adult↗

Mammography and the primary care management of breast lumps.

Breast cancer is the commonest cause of death from malignancy in women in the Western world. Although advances have been made in treatment, 11,000 women a year continue to die from the disease in Britain. Prognosis is undoubtedly better with early diagnosis, and this may best be achieved by prompt referral to a breast unit if a persistent mass is suspected clinically.

Adolescent↗

Cloning and DNA sequence of plasmid determinant iss, coding for increased serum survival and surface exclusion, which has homology with lambda DNA.

Escherichia coli K12 cells carrying a cloned 1.4 kb HindIII fragment from plasmid ColV2-K94, showed increased survival in guinea pig serum. The recombinant plasmid also conferred group II surface exclusion, i.e. the cells were reduced in recipient ability towards the incoming plasmid R538drd in conjugation experiments. Southern blotting suggested homology with bacteriophage lambda DNA and to the insertion element IS2. Determination of the DNA sequence of the fragment demonstrated the presence of a truncated IS2 (165 bp), separated by 250 bp from a 900 bp stretch of homology with lambda DNA, beginning within the Rz gene and continuing in the rightward direction on the lambda map. A 97 amino acid open reading frame (ORF) adjacent to Rz and on the opposite strand, remained intact in iss, with several amino acid changes. The ORF in iss is preceded by sequences resembling prokaryotic ribosome binding sites and promoters.

Amino Acid Sequence↗

Xanthine oxidase-derived oxygen radicals induce pulmonary edema via direct endothelial cell injury.

Pulmonary hypoperfusion/ischemia-reperfusion (I/R) may initiate ARDS (nonhydrostatic pulmonary edema). Endothelial damage via xanthine oxidase (XO)-derived oxygen radicals (O2*) may mediate I/R injury. We previously documented Factor VIII antigen (F8) as a marker for endothelial injury. The purpose of this study was to (1) document I/R-induced nonhydrostatic pulmonary edema, (2) identify whether XO or O2* mediates nonhydrostatic edema, and (3) identify the site of injury (? endothelium). Rat lungs were isolated, ventilated, and perfused (100 min, control, or 40 min at 37 degrees C, I (static vent.), + 60 min, R). Effluent was analyzed for F8 release (ELISA: data relative to control). Tungsten-fed rats had negligible lung XO vs rats fed standard diet (3.6 vs 34.5 mU/g, (P less than 0.05). Catalase (CAT) 50 micrograms/ml) was added to perfusate prior to R. Sectioned lungs were fluorescein anti-F8 photographed (IF) and qualitatively assessed. (Table: see text). We conclude that (1) pulmonary hypoperfusion (I/R) leads to nonhydrostatic pulmonary edema, and (2) the edema results in part from XO-generated O2* directed at the capillary endothelium.

Animals↗

Endotoxin pretreatment increases endogenous myocardial catalase activity and decreases ischemia-reperfusion injury of isolated rat hearts.

Hearts isolated from rats pretreated 24 hr before with endotoxin had increased myocardial catalase activity, but the same superoxide dismutase, glutathione peroxidase, glutathione reductase, and glucose-6-phosphate dehydrogenase activities, as hearts from untreated rats. Hearts isolated from rats pretreated with endotoxin 24 hr before also had increased myocardial function (decreased injury) after ischemia and reperfusion (Langendorff apparatus, 37 degrees C), as assessed by measurement of ventricular developed pressure, contractility (+dP/dt), and relaxation rate (-dP/dt), compared to control hearts. In contrast, hearts isolated from rats pretreated with endotoxin 1 hr before isolation or hearts perfused with endotoxin did not have increased catalase activity or decreased injury following ischemia and reperfusion. Aminotriazole pretreatment prevented increases in myocardial catalase activity and myocardial function after ischemia-reperfusion in hearts from endotoxin-pretreated rats. The results suggest that endotoxin pretreatment decreases cardiac ischemia-reperfusion injury and that increases in endogenous myocardial catalase activity contribute to protection.

Amitrole↗

Chronic Budd-Chiari syndrome due to congenital membranous obstruction of the inferior vena cava: clinical experience.

Budd-Chiari syndrome due to congenital membranous obstruction of inferior vena cava can be cured by appropriate surgical correction. A high index of suspicion is required to identify this condition and investigate it properly. Experience of three such cases is presented; two had a successful surgical correction and one refused any surgical intervention. Both patients who underwent operation are doing well and are symptom-free after 4 and 6 years, respectively. The diagnosis and the presentation of inferior vena caval obstruction and the various surgical procedures that are available for relieving the congenital obstruction of inferior vena cava are reviewed.

Adult↗

Intrathoracic oesophageal perforations following bougienage: a protocol for management.

Perforation of the thoracic oesophagus is a serious complication of oesophagoscopy and bougienage for oesophageal strictures. In the last 7 years, 10 such cases have been treated without mortality by following a particular treatment protocol. Irrespective of the duration of perforation, extent of contamination or severity of symptoms, all patients underwent thoracotomy for pleuromediastinal toilet and drainage. Decompressive gastrostomy and feeding jejunostomy was done and a nasogastric tube was left across the stricture to serve as a stent. A thread attached to the nasogastric tube helped in retrograde dilatation after healing of perforation. Infection was controlled with intravenous gentamicin, cloxacillin and metronidazole. In all patients, the perforation healed. Colonic transposition was done in three cases at a later date. The rest required periodic dilatation of the oesophagus either by peroral or retrograde approach.

Adolescent↗

Studies on lipids in mycobacterial cell wall: their important structure and function relating to pathogenicity and their biological activity.

The lipids cord-factor, mycosides and sulpholipids are supposed to be vitally linked with the pathogenecity of mycobacteria. In this paper an attempt has been made to clarify the understanding of the occurrence, organisation and possible interaction of the diverse lipids present in the mycobacterial cell wall and their possible structure and function.

Cell Wall↗

Optimal hypothermic preservation of arrested myocardium in isolated perfused rabbit hearts: a 31P NMR study.

The purpose of this study was to (1) relate myocardial high-energy phosphate stores to functional recovery after ischemia and reperfusion, (2) assess the bioenergetics and functional influence of clinically relevant myocardial hypothermia, and (3) examine tissue pH as an independent indicator of postischemic recovery of function. Rabbit hearts were perfused via a modified Langendorff technique, monitored for developed pressure (DP) and left ventricular end-diastolic pressure (LVEDP) via an isovolumic left ventricular balloon catheter, and placed in a Brucker NMR magnet (4.7 tesla) to measure phosphocreatine (PCr), adenosine triphosphate (ATP), and pH. Hearts underwent 1 hour of global ischemia at 7 degrees, 17 degrees, 27 degrees and 37 degrees C initiated by one dose of K+ cardioplegia followed by 30 minutes of reperfusion. After reperfusion, DP (expressed as a percentage of preischemic control) and LVEDP (mm Hg) in 7 degrees and 17 degrees C hearts were no different (96 + 5% vs 97 +/- 3%; 5 +/- 2 mm Hg vs 6 +/- 2 mm Hg; p = NS), but were better (p less than 0.01) than 27 degree hearts (72 +/- 6%, 17 +/- 6 mm Hg) and 37 degree hearts (31 +/- 7%, 60 +/- 6 mm Hg). PCr was severely depleted in all groups. ATP was 90 +/- 7% and 87 +/- 5% of preischemic control in the 7 degree and 17 degree hearts, which was significantly better than the 68 +/- 3% and 21 +/- 3% in the 27 degree and 37 degree groups (p less than 0.01). The pH at end ischemia was 6.83, 6.89, 6.54, and 5.86 for the 7 degree, 17 degree, 27 degree, and 37 degree hearts, respectively (7 degrees vs 27 degrees or 37 degrees, p less than 0.01; 17 degrees vs 27 degrees or 37 degrees, p less than 0.01). Linear regression of DP on end-ischemic ATP (EIATP) and end-ischemic pH revealed: DP = 0.96 (EIATP) + 20 (r = 0.92) and DP = 60 (pH) -317 (r = 0.86). We conclude that (1) end-ischemic ATP predicts recovery of ventricular function, and, furthermore, there appears a threshold ATP concentration (80% of control) below which full recovery of function will not occur; (2) end-ischemic pH predicts recovery of ventricular function; (3) 7 degrees C hypothermic ischemia does not cause a clinically significant cold injury; and (4) in a single-dose crystalloid cardioplegia model, end-ischemic pH is linearly related to recovery of function (r = 0.86).

Adenosine Triphosphate↗

The coincidence of myocardial reperfusion injury and hydrogen peroxide production in the isolated rat heart.

To investigate the specific nature and timing of oxygen (O2) metabolite reperfusion injury, we used a rat-heart model (Langendorff's solution, 37 degrees C) and hydrogen peroxide (H2O2)-dependent aminotriazole inactivation of catalase as a measure of myocardial H2O2 before, during, and after ischemia. We found that after ischemia (20 minutes, global, 37 degrees C), ventricular functional loss--as assessed by measurement of developed pressure (DP), +dp/dt, and -dp/dt with a ventricular balloon--occurred at 10 minutes of reperfusion and that myocardial H2O2 production was maximal by this time. Furthermore, H2O2 production did not occur during ischemia, and inhibition of xanthine oxidase by tungsten feeding or infusing a permeable O2 metabolite scavenger during reperfusion (dimethylthiourea) prevented ventricular functional loss. We conclude that (1) reperfusion injury is in part mediated by toxic oxygen metabolites, (2) H2O2 is the central O2 metabolite responsible for reperfusion injury, and (3) the timing of H2O2 production coincides with the timing of ventricular functional loss.

Amitrole↗