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Biomedical subjects

A Bhattacharyya

Publications and source records attributed to A Bhattacharyya.

At least 73 records · Page 4Linked to original sources
PubMed1999

Durability of new squamous epithelium after endoscopic reversal of Barrett's esophagus.

BACKGROUND: Endoscopic reversal of Barrett's esophagus with multipolar electrocoagulation and high-dose omeprazole has been previously described but long-term results are not available. The aim of this study was to follow patients after endoscopic reversal and to perform a detailed analysis of the "new" squamous mucosa. METHODS: After reversal, patients with Barrett's esophagus were maintained on high-dose omeprazole and underwent interval endoscopy, and large biopsies were obtained of the former Barrett's epithelium. RESULTS: Nine of 11 patients were men; the mean age was 62 years. The mean length of Barrett's mucosa was 4.4 cm; the mean dose of omeprazole used was 49 mg/day. All patients had an initial complete response to treatment-no evidence of Barrett's endoscopically and histologically. Three patients had intestinal metaplasia underlying the new squamous mucosa in the latest follow-up biopsies. In these 3 patients, only 0.4%, 2%, and 8% of the total biopsy area had intestinal metaplasia. All but 4 patients had underlying intestinal metaplasia at variable times during the study period. Patients have been followed for a mean of 36 months (range 19 to 53 months). CONCLUSIONS: New squamous mucosa is durable and resembles normal squamous tissue. Underlying glands of intestinal metaplasia are intermittently found. Because the significance of this residual intestinal metaplasia is unclear, surveillance endoscopy with biopsies of the treated segment is recommended even after reversal therapy.

Aged↗
PubMed1999

Nonresponding schizophrenia: differentiation by neurological soft signs and neuropsychological tests.

Schizophrenia patients have higher scores on neurological soft-signs (NSS) and show greater deficits on a variety of neuropsychological tests than normal control subjects and mixed groups of psychiatric patients. Among chronic schizophrenia patients it is unclear which of these types of deficits most strongly differentiates patients who remain consistently symptomatic in spite of treatment with several conventional neuroleptics (nonresponders) as compared with relapsing chronic schizophrenia patients who improve substantially with treatment (relative responders). In this study, 25 nonresponders and 20 relative responders to conventional neuroleptics were compared on an NSS battery and a limited number of neuropsychological tests, which evaluated deficits influenced by functioning of frontal and nonfrontal brain areas. NSS scores showed the largest difference between relative responders and nonresponders, and statistical analyses suggested that NSS scores were the strongest differentiator between the two groups of chronic schizophrenia patients. Scores differentiating the two groups involved deficits influenced by both frontal and nonfrontal functioning. A predominance of negative symptoms in the current clinical picture was highly correlated with high NSS scores.

Adult↗
PubMed1999

Diabetic ketoacidosis precipitated by thyrotoxicosis.

We report two patients with type 1 diabetes mellitus, previously well controlled with good compliance, presenting with unexplained diabetic ketoacidosis. Following initial correction of the metabolic disorder, persisting tachycardia lead to the diagnosis of thyrotoxicosis. In both cases, treatment with propranolol and carbimazole helped in the stabilization of their metabolic states. Although thyrotoxicosis is known to destabilize diabetes control, we can find no reports of it precipitating diabetic ketoacidosis.

Adult↗
PubMed1999

Coeliac disease in adults: variations on a theme.

In childhood, coeliac disease (gluten enteropathy) tends to show itself with failure to thrive and growth retardation; in adult life with malabsorption syndromes. We report six cases in adults who presented atypically, with features including clotting disorder, hypoglycaemia, weight loss, anaemia and angina pectoris, all of which responded to gluten withdrawal.

Aged↗
PubMed1999

Thyrotoxicosis in old age: a different clinical entity?

Thyrotoxicosis generally presents with classic signs and symptoms in younger people. Among the elderly population atypical presentation is recognized, although this has not been well quantified or characterized. To avoid misdiagnosis or delay in diagnosis, clinical suspicion needs to remain high.

Aged↗
PubMed1999

Atrial fibrillation in a general hospital: how well are we doing?

Atrial fibrillation (AF) is an important risk factor for ischaemic stroke, and anticoagulation is now indicated in many patients, particularly those with congestive cardiac failure, hypertension, a history of transient ischaemic attacks or embolic stroke. In a retrospective study (and audit), we examined 280 cases of AF (acute, paroxysmal non-sustained and chronic sustained) admitted to a general hospital in the UK. The commonest underlying medical condition was ischaemic heart disease (57%), while the commonest presenting feature was congestive cardiac failure (60%). Pharmacological cardioversion was preferred against electrical cardioversion for reverting to sinus rhythm. Fifty-six patients (20%) received warfarin, 55 patients (20%) were on aspirin, and the remaining 169 (60%) received neither warfarin nor aspirin. More awareness is needed among physicians managing AF particularly in relation to anticoagulation.

Acute Disease↗
PubMed1999

Hypertension in elderly--an overview.

Hypertension (HT) is a common disease in elderly. It has different pathophysiologic, clinical and therapeutic implications in this age group. Due to loss of arterial wall elasticity with age, major vessels including aorta become stiff and less distensible. As age advances, these stiff vessels also lose beta adrenergic responsiveness with unchanged alpha adrenergic responsiveness. These together raise peripheral vascular resistance and aortic impedance which needs a powerful systolic ejection of left ventricle to maintain cardiac output. Result is rise in systolic blood pressure (SBP) and increase in left ventricular (LV) mass with compromised cardiac output and renal blood flow. Participation of renin-angiotensin system and kidney in HT pathogenesis in elderly are minimum. Diagnosis of HT in elderly is made if SBP > 140 mm Hg and/or diastolic blood pressure (DBP) > 90 mm Hg or is taking antihypertensive medications. Isolated systolic hypertension (ISH) means SBP > 140 mm Hg with DBP < 90 mm Hg. Measurement of blood pressure (BP) is problematic, mainly due to pseudo HT, postural hypotension and white-coat HT. HT in absence of end organ changes suggest pseudo HT. Postural hypotension must be detected and treated. Systolodiastolic HT, carried over from middle age is the commonest type of HT in elderly. ISH is also common (10%). Atherosclerotic renovascular disease can cause secondary HT. Therapy is always needed in HT in elderly. Chance of coronary artery disease (CAD) and cerebrovascular accident (CVA) are quite high amongst elderly hypertensives. SBP is more dangerous than DBP. Benefits of therapy are more when compared to young. HT should be treated if SBP > 160 mm Hg and/or DBP > 90 mm Hg. ISH needs therapy if SBP > 160 mm Hg. The benefits of therapy becomes less after 80 years. Treatment goal should be to keep BP below 140/90 mm Hg. Therapy should be gradual and stepwise. Na-restriction should be modest. Diuretics (e.g., thiazide 25 mg/day) are the drug of choice unless contra-indicated. Beta blockers are inferior agents compared to diuretics unless angina or acute myocardial infarction (AMI) is present. Angiotensin converting enzyme (ACE) inhibitors are drug of choice only if congestive cardiac failure (CCF) and/or diabetes is present or other drugs are contra-indicated. Calcium entry blockers (CEB) are new but very good alternative to diuretics in elderly. Due to abnormal physiology, pharmacokinetics and drug interactions, side-effects are very common in elderly. They should be detected early and treated.

Adrenergic beta-Antagonists↗
PubMed1998

Xrcc3 is required for assembly of Rad51 complexes in vivo.

Rad51 is a member of a family of eukaryotic proteins related to the bacterial recombinational repair protein RecA. Rad51 protein localizes to multiple subnuclear foci in Chinese hamster ovary cells. Subnuclear Rad51 foci are induced by ionizing radiation or the DNA cross-linking agent cisplatin. Formation of these foci is likely to reflect assembly of a multimeric form of Rad51 that promotes DNA repair. Formation of damage-induced Rad51 foci does not occur in the Chinese hamster ovary cell line irs1SF, which is sensitive to DNA damaging agents. The Rad51 focus formation defect of irs1SF cells is corrected by a construct that encodes the repair protein Xrcc3. Xrcc3 is a human homolog of Rad51 previously isolated by virtue of its ability to correct the radiation sensitivity of irs1SF cells. Changes in the steady state level of Rad51 protein do not account for the irs1SF defect nor do they account for the appearance of foci following DNA damage. These results suggest that Xrcc3 is required for the assembly or stabilization of a multimeric form of Rad51 during DNA repair. Cell lines defective in two different components of DNA protein kinase formed Rad51 foci in response to damage, indicating DNA protein kinase is not required for damaged-induced mobilization of Rad51.

Animals↗
PubMed1998

Metabolic Study of Isoproturon in Goats Following a Single Oral Administration: Toxicokinetics and Recovery.

Toxicokinetic behavior and recoveries of isoproturon from feces, urine, and different tissues of goat were determined after 4, 5, 6, and 7 days following single oral administration at 500 mg/kg. Isoproturon was rapidly absorbed and attained blood concentration within 15 min of administration. The kinetic behavior followed a two-compartment open model. The higher t(1/2)(beta) (9.78 +/- 0.33 h) and V(d)()area (4.49 +/- 0.41 L/kg) associated with lower Cl(B) (0.32 +/- 0.02 L/kg/h) suggested slow elimination from the blood. Approximately 56% of the total administered compound was recovered from feces. The rate of excretion of isoproturon through feces was maximum at 48 h and could not be detected beyond 120 h. The excretion pattern of isoproturon through urine resembled that of feces, and approximately 10-11% was eliminated in urine. A maximum quantity of residue was detected in all tissues of goats slaughtered after 4 days followed by a substantial decline after day 5, and nothing could be detected after day 7. Histopathological study revealed that isoproturon produced moderate cellular changes like fatty degeneration in the liver and kidney and emphysema in the lung after 7 days post administration.

Journal Article↗
PubMed1998

A cognate tRNA specific conformational change in glutaminyl-tRNA synthetase and its implication for specificity.

Conformational changes that occur upon substrate binding are known to play crucial roles in the recognition and specific aminoacylation of cognate tRNA by glutaminyl-tRNA synthetase. In a previous study we had shown that glutaminyl-tRNA synthetase labeled selectively in a nonessential sulfhydryl residue by an environment sensitive probe, acrylodan, monitors many of the conformational changes that occur upon substrate binding. In this article we have shown that the conformational change that occurs upon tRNA(Gln) binding to glnRS/ATP complex is absent in a noncognate tRNA tRNA(Glu)-glnRS/ATP complex. CD spectroscopy indicates that this cognate tRNA(Gln)-induced conformational change may involve only a small change in secondary structure. The Van't Hoff plot of cognate and noncognate tRNA binding in the presence of ATP is similar, suggesting similar modes of interaction. It was concluded that the cognate tRNA induces a local conformational change in the synthetase that may be one of the critical elements that causes enhanced aminoacylation of the cognate tRNA over the noncognate ones.

2-Naphthylamine↗
PubMed1998

Methylene blue staining for intestinal metaplasia of the gastric cardia with follow-up for dysplasia.

BACKGROUND: Previous studies by our group have identified a 23% prevalence of intestinal metaplasia involving the gastric cardia in patients undergoing elective esophagogastroduodenoscopy (EGD). The current study evaluates the potential clinical utility of vital staining with methylene blue for detecting intestinal metaplasia of the cardia. In addition, the prevalence of Helicobacter pylori infection and incidence of dysplasia in cardia intestinal metaplasia was assessed. METHODS: Twenty-four of 104 patients undergoing elective EGD were previously identified with cardia intestinal metaplasia. Twenty-one of these 24 returned for follow-up EGD with methylene blue staining and cardia biopsies. During EGD four random biopsies were taken in the cardia. After staining with methylene blue, four targeted biopsy specimens were taken from any stained areas. H. pylori infection was assessed by rapid urease testing and serologic evaluation. RESULTS: Staining with methylene blue was positive in 16, equivocal in 4, and negative in 1. Overall, cardia intestinal metaplasia was identified in 17 of 21 patients (81%) by at least one of the 8 biopsies. The sensitivity of detecting intestinal metaplasia by targeted biopsies to stained areas was 67% as opposed to 38% for random biopsies (odds ratio 3.0: 95% CI [0.88,10.24]). The prevalence of H. pylori infection in patients with cardia intestinal metaplasia was 76%. One patient developed low-grade dysplasia, whereas the others remained negative. CONCLUSIONS: Intestinal metaplasia of the gastric cardia is associated with a high prevalence of H. pylori infection and is a reproducible finding in the majority of patients. Methylene blue staining and an increasing number of biopsies improve the sensitivity of detecting this potentially neoplastic lesion.

Aged↗
PubMed1998

A fluorescence spectroscopic and molecular dynamics study of bis-ANS/protein interaction.

Despite emergence of bis-ANS as a major fluorescence probe of proteins structure, conformational and spectroscopic properties of protein/bis-ANS complexes remains largely unexplored. We have shown that fluorescence polarization of both ANS and bis-ANS is excitation wavelength dependent and this is a property of all protein-ANS/bis-ANS complexes studied. Bis-ANS excitation maximum is always more red shifted than the corresponding ANS complex. Even when corrected for the red shift, the bis-ANS complexes in some, but not all, cases show only a little lowering of polarization, suggesting modest additional depolarization in bis-ANS compared to ANS. Calculation of energy migration rate between the two rings suggests that energy migration rate should be high at all values of the naphthyl-naphthyl dihedral angle. Although, Molecular mechanics and dynamics calculations show that the lowest energy conformation of bis-ANS is when the two naphthalene rings are roughly perpendicular to each other, due to rapid energy migration this conformation should lead to dramatic lowering of emission anisotropy, unlike what is observed. Salt and temperature dependence of bis-ANS/protein interaction suggests little ionic interaction and pre-dominant interaction through hydrophobic aromatic rings. We conclude that bis-ANS binds to proteins through interaction with the aromatic rings and with two rings nearly parallel to each other.

Amino Acyl-tRNA Synthetases↗