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Biomedical subjects

D Bandyopadhyay

Publications and source records attributed to D Bandyopadhyay.

At least 19 recordsLinked to original sources
PubMed2006

Estimation of strength in different extra Watson-Crick hydrogen bonds in DNA double helices through quantum chemical studies.

It was shown earlier, from database analysis, model building studies, and molecular dynamics simulations that formation of cross-strand bifurcated or Extra Watson-Crick hydrogen (EWC) bonds between successive base pairs may lead to extra rigidity to DNA double helices of certain sequences. The strengths of these hydrogen bonds are debatable, however, as they do not have standard linear geometry criterion. We have therefore carried out detailed ab initio quantum chemical studies using RHF/6-31G(2d,2p) and B3LYP/6-31G(2p,2d) basis sets to determine strengths of several bent hydrogen bonds with different donor and acceptors. Interaction energy calculations, corrected for the basis set superposition errors, suggest that N-H...O type bent EWC hydrogen bonds are possible along same strands or across the strands between successive base pairs, leading to significant stability (ca. 4-9 kcal/mol). The N-H...N and C-H...O type interactions, however, are not so stabilizing. Hence, consideration of EWC N-H...O H-bonds can lead to a better understanding of DNA sequence directed structural features.

Base Pairing↗
PubMed2005

Small bowel obstruction due to inflammation secondary to ingested bone.

We report the CT appearances of an ingested pork bone in the lumen of small bowel in a 66-year-old man with an intact and virgin gastrointestinal tract. CT scan demonstrated the site of obstruction at distal jejunum with associated irregular narrowing and proximal small bowel dilatation as well as the bone lodged in the non-dilated terminal ileum. Laparotomy and histology of the resected small bowel confirmed the CT appearances that the obstruction was caused by adhesions and extensive inflammation across the bowel wall in the distal jejunum from trauma as the bone traversed down the lumen. We believe that this is the first reported preoperative CT scan finding of a case of small bowel obstruction due to adhesions and inflammation secondary to ingested bone.

Aged↗
PubMed2005

Successful treatment of a patient with chronic lymphocytic leukaemia (CLL) presenting with bony metastases with aggressive antibody and chemotherapy.

Osteolytic lesions are rare in chronic lymphocytic leukaemia (CLL) and thought to result from Richter's transformation or metastatic disease from nonlymphoid malignancies. We report a patient who presented with a large femoral metastatic lesion and hypercalcaemia caused by CLL itself. Complete remission of CLL with resolution of the osteolytic lesion was achieved with rituximab and cyclophosphamide, adriamycin, oncovin and prednisolone [CHOP (R-CHOP)] combination chemotherapy.

Aged, 80 and over↗
PubMed2005

Direct Access Minor Surgery service--patient satisfaction and effectiveness.

INTRODUCTION: Waiting lists for surgical out-patients and elective operations are a major concern of the National Health Service. A Direct Access Minor Surgery programme in an ambulatory minor theatre area has been introduced to expedite patient treatment. The response of patients to this service has been assessed. PATIENTS AND METHODS: A postal questionnaire was offered to all patients attending for the Direct Access Minor Surgery over a period of 20 months (January 2002 to August 2003). Patients were asked about direct attendance for surgery without a prior out-patient appointment, about waiting time before operation on the day of surgery and the adequacy of pre-operative information. Overall satisfaction was assessed using a scoring system. The incidence of inappropriate referrals was analysed. The influence of the service on waiting lists and resources was assessed. RESULTS: A total of 221 patients were operated on, 257 lesions being excised. Response rate to the postal questionnaire was 55%. Of respondents, 75% thought that it was appropriate to attend the hospital directly without an out-patient clinic appointment. To 83% the waiting time was acceptable. Of patients, 90% were happy with the pre-operative information. Overall, 91% of respondents were very satisfied with the service. Inappropriate referrals were 4%. The new service reduced waiting time for minor surgery from 53 to 10 weeks. It also released approximately 140 new out-patient slots per annum. CONCLUSION: Direct Access Minor Surgery is a safe and favoured service with high patient satisfaction.

Health Services Accessibility↗
PubMed2004

Analysis of differentially expressed genes in hyperthyroid-induced hypertrophied heart by cDNA microarray.

Experiments were carried out to identify the altered genes in hyperthyroid rat heart and their influence on the functions of cardiac myocytes. Chronic treatment of rats with 3,5,3' triiodo-L-thyronine (T3) resulted in a prominent increase in the size of the left ventricle with increased wall thickness and reduced chamber volume leading to concentric cardiac hypertrophy. The heart weight to body weight ratio (HW/BW) in hyperthyroid rats was increased by about 58% over that of normal rats. Using cDNA microarray comprising 588 genes, we compared the differences in mRNA expression of hyperthyroid and normal rat heart. Based on a threshold of greater than 10% change, about 37 genes were found to be regulated by T3. Further analyses by Western blotting, Northern blotting and real-time quantitative RT-PCR of some of the genes confirmed the microarray results. The T3-altered genes encode various types of proteins related to metabolism, matrix and cytoskeletal structures, growth factors, transcription factors, Ca(2+)-channels etc. The physiological significance of one of these altered proteins in hyperthyroid heart, insulin-responsive glucose transporter (GLUT) type 4 (GLUT4), was studied in detail. The expression of GLUT4 was drastically reduced in the ventricular tissues of hyperthyroid heart. Insulin-induced glucose uptake in hyperthyroid cardiomyocytes was reduced significantly, indicating the impaired glucose transport in cardiac cells. Interestingly, a few genes such as GLUT4, cytochrome P450 isoforms, superoxide dismutase (SOD), collagens, matrix metalloproteinases (MMP), tissue inhibitors of matrix metalloproteinases etc. which had not been reported earlier were found to be altered in hyperthyroid heart. Our results show some new aspects of hyperthyroid heart which will be important in assessing the pathophysiology of hypertrophied cardiomyocytes.

Animals↗
PubMed2004

Diarrhea management among under fives.

This study was conducted to assess the magnitude of the problem of diarrhea and time of initiation of its management in under five children of different socio economic status, in an urban area of West Bengal. Overall prevalence of diarrhea was 31.67%, highest in lower socio economic class (41%). Prevalence was higher in the girls, though not significant. Acute watery diarrhea was most common (58.9%), followed by dysentery (24. 2 %) and persistent diarrhea (16.9%). Persistent type was inversely proportional to socioeconomic status. Majority of mothers administered fluids or sought treatments within six hours in the middle socioeconomic class but beyond six hours in lower socioeconomic group (P < 0.001). Percentage of children where doctors' advice was implemented within 12 hours was inversely proportional to socio economic status (P <0.001).

Age Factors↗
PubMed2004

Insulin in type 2 diabetes: promises to keep.

The concept which has evolved in the management of type 2 diabetes mellitus is early insulin therapy. In type 2 diabetes mellitus first phase insulin response is grossly impaired on eventually absent, overburdening phase 2 responses which obviously fail to compensate in the long run. Perpetuation of the age old practice to continue OHA while almost all beta-cells are exhausted is only buying time for starting insulin. Preservation of beta-cell function by early insulin therapy yields two important benefits: (1) Better glycaemic control at lower medication dose and (2) relative freedom from hypoglycaemia because of well preserved glucagon response. To ensure and to translate the proper action of insulin in the target organs we are now talking about designer insulins which are basically insulin analogues (short and long acting). So type 2 diabetes is a growing menace and is responsible for severe morbidity, mortality and poor quality of life. Good glycaemic control from the very beginning of diabetes has shown to favourably influence all of these and is accepted as a cardinal goal of proper diabetes care.

Diabetes Mellitus, Type 2↗
PubMed2004

Glycaemic consequences of HIV and highly active antiretroviral therapy: a pilot study and review of literature.

The metabolic consequences of HIV and AIDS are accentuated in the setting of highly active antiretroviral therapy. Peripheral lipodystrophy, central adiposity, hyperlipidaemia, insulin resistance and diabetes mellitus are frequent associations of protease inhibitor containing highly active antiretroviral therapy regimens. Ninety patients aged 25-50 years (males 52, females 38), seropositive for HIV 1 and 2 or both were selected to see the glycaemic profiles in asymptomatic early HIV disease with CD4 counts > 100/microl and to compare this with the glycaemic profile of (a) advanced HIV disease (CD4 counts < 200/microl), not on highly active antiretroviral therapy and (b) advanced HIV disease (CD4 counts < 200/microl), on uninterrupted non-protease inhibitor highly active antiretroviral therapy > 6 months. All the patients were grouped into 3: (1) Group A: CD4 counts > 500/microl (n=37), highly active antiretroviral therapy naive, (2) group B: CD4 counts < 200/microl (n=21), not on highly active antiretroviral therapy, and (3) group C: CD4 counts < 200/microl, receiving uninterrupted non-protease inhibitor based highly active antiretroviral therapy for > 6 months (n=32). The fasting blood glucose, glycosylated Hb (HbA1c) levels, were measured in all the patients in 3 groups and significance of difference between means was calculated among various groups. Body weight and waist-hip ratio were also measured. The results were analysed and compared with other studies.

Adult↗
PubMed2003

Parathyroid hormone-related protein in pancreatic exocrine cancer associated with hypercalcaemia.

Hypercalcaemia is a common complication of malignancy seen in about 10% of cases of advanced cancer. Although hypercalcaemia is not uncommon with endocrine tumour of the pancreas, hypercalcaemia with cancer of the exocrine pancreas unrelated to bone metastasis has been rarely reported. We report a case of undifferentiated pancreatic cancer with severe hypercalcaemia due to parathyroid hormone-related protein produced by the tumour cells that did not respond to medical management.

Fatal Outcome↗
PubMed2003

Neurally-mediated and neurally-independent beneficial actions of melatonin in the gastrointestinal tract.

Melatonin (N-acetyl-5-methoxytryptamine), originally discovered in the pineal gland, is now known also to be present in the gastrointestinal tract from the stomach to the colon. It is localized and likely synthesized in the enterochromaffin cells of the mucosal lining. Its functions in the gut generally seem to be protective of the mucosa from erosion and ulcer formation and to possibly influence movement of the gastrointestinal contents through the digestive system. In this brief review, we summarize the work documenting the function of melatonin in influencing bicarbonate secretion in the stomach and its role in preventing and repairing ulcers in the stomach and duodenum. Melatonin's actions in the control of bicarbonate secretion involve the central and peripheral sympathetic nervous systems and the actions are receptor mediated. Conversely, melatonin's actions in reducing ulcer formation also seemingly involve the ability of the indole to directly scavenge toxic oxygen-based reactants, e.g., the hydroxyl radical, and possibly to promote antioxidative enzyme activities. These same processes may be involved in the mechanisms by which melatonin promotes ulcer healing. Additionally, however, melatonin's effects on the healing of ulcers includes actions of blood flow in the margins of the ulcer and also on the sensory nerves. All indications are that melatonin has a variety of beneficial effects in the gastrointestinal tract. It is likely, however, that additional actions of melatonin on the digestive system will be uncovered.

Animals↗
PubMed2002

Large bowel ischemia following laparoscopic inguinal hernioplasty.

The adverse physiological effects of pneumoperitoneum are well understood. However, the clinical implications of compromised mesenteric circulation through several mechanical and physiological mechanisms are not as well recognized. We describe a fatal case of large bowel ischemia following an elective laparoscopic transperitoneal inguinal hernioplasty. The patient was a 78-year-old man who died within 30 h after an uneventful anesthesia and laparoscopic surgery. An autopsy revealed thrombosis of the inferior mesenteric artery and an infrarenal aortic aneurysm with thrombotic plaque on its wall. We reviewed the relevant literature on laparoscopic procedures and mesenteric ischemia. To our knowledge, this is the first reported case of large bowel ischemia following pneumoperitoneum. We conclude that the presence of an aortic aneurysm is an added risk factor in laparoscopy.

Aged↗
PubMed2002

"The stones...to rise".

Late complications of laparoscopic cholecystectomy are less addressed. Spillage of stone during laparoscopic cholecystectomy is a recognized complication. However, late sequelae of spillage of stones are less clear. We report a case of late and recurrent subphrenic abscess following laparoscopic cholecystectomy. This was a 65-year-old gentleman who underwent laparoscopic cholecystectomy in 1991. He presented 3 years and even 10 years after the operation with subphrenic abscess. Interesting CT scan findings are described. Surgical open drainage is recommended as opposed to percutaneous drainage. Emphasis is given to take precautions to avoid spillage of stones. We feel that this is the first case of a complication of laparoscopic cholecystectomy presenting so late and as a recurrent problem.

Aged↗
PubMed2001

Cytoplasmic localization of the oncogenic protein Ski in human cutaneous melanomas in vivo: functional implications for transforming growth factor beta signaling.

The oncogenic protein Ski associates with Smad proteins and counteracts their activation of gene expression and growth inhibition in response to transforming growth factor beta (TGF-beta). Here we show that Ski protein levels are increased in all 44 human melanoma tumor tissues analyzed in vivo. In addition, Ski subcellular localization changes from nuclear, in preinvasive melanomas (melanomas in situ), to nuclear and cytoplasmic in primary invasive and metastatic melanomas. Furthermore, Ski/Smad association in the cytoplasm seems to prevent Smad3 nuclear translocation in response to TGF-beta. The biological significance of Ski overexpression in melanomas was established by showing that down-regulation of Ski levels, by antisense Ski vectors, restored TGF-beta-mediated growth inhibition. Such inhibition is apparently mediated by up-regulation of the cyclin-dependent kinase-I p21(Waf-1) and inhibition of cyclin-dependent kinase 2 activity. Our results suggest that high levels of Ski in human melanomas produce a disruption of TGF-beta signaling phenotypically similar to that in cells harboring mutations in TGF-beta receptors or Smad proteins, and this may represent a significant event in the progression of melanomas in vivo.

Cell Division↗