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Biomedical subjects

D Banerjee

Publications and source records attributed to D Banerjee.

At least 19 recordsLinked to original sources
PubMed2006

The effect of sibutramine-assisted weight loss in men with obstructive sleep apnoea.

OBJECTIVE: Obstructive sleep apnoea (OSA) occurs frequently in obese patients and may be reversible with weight loss. Obstructive sleep apnoea and obesity are both independent risk factors for hypertension and increased sympathetic activity. Sibutramine has been increasingly used in the management of obesity, but is relatively contraindicated in patients with hypertension. No studies have investigated the effect of sibutramine on OSA, blood pressure and heart rate. We aimed to assess the changes in OSA and cardiovascular parameters in obese men with OSA enrolled in a sibutramine-assisted weight loss programme (SIB-WL). DESIGN: Open uncontrolled cohort study of obese male subjects with OSA in an SIB-WL. SUBJECTS: Eighty-seven obese (body mass index =34.2+/-2.8 kg/m(2)) middle-aged (46.3+/-9.3 years) male subjects with symptomatic OSA (Epworth score 13.4+/-3.6; respiratory disturbance index (RDI) 46.0+/-23.1 events/h) completed the study. RESULTS: At 6 months, there was significant weight loss (8.3+/-4.7 kg, P<0.0001), as well as a reduction in waist and neck circumference and sagittal height (all P<0.0001). These changes were accompanied by a reduction in OSA severity (RDI fell by 16.3+/-19.4 events/h and Epworth score by 4.5+/-4.6), both P<0.0001). There was no significant change to systolic (P=0.07) or diastolic blood pressure (P=0.87); however, there was a mild rise in resting heart rate (P<0.0001). CONCLUSION: Moderate (approximately 10%) weight loss with SIB-WL results in improvement in OSA severity without increase in blood pressure in closely monitored OSA subjects.

Adult↗
PubMed2006

Pre-clinical toxicology and pathology of 9-(2'-hydroxyethylamino)-4-methyl-1-nitroacridine (C-1748), a novel anti-cancer agent in male Beagle dogs.

We have developed a group of 4-substituted-1-nitroacridines with potent anti-tumor activity against prostate cancer and less toxic than parent 1-nitroacridines. The most active 9-(2'-hydroxyethylamino)-4-methyl-1-nitroacridine (C-1748) was selected for pre-clinical studies. The current study was undertaken to evaluate clinical and/or morphological adverse effects of C-1748 as a single intravenous dose at concentrations ranging from 0.16 to 4.6 mg/kg administered to male Beagle dogs. The maximum tolerated dose was 1.5 mg/kg. Emesis was observed in all groups lasting an average of 30 min to 12 h post-dosing. At high dose, extreme aggression was observed in one dog followed by disorientation and depression lasting for 48 h a frequent observation with chemotherapy. Reductions in platelets and white blood cells were observed which was similar to that seen with other chemotherapeutic agents. A compensatory hyperplasia of lymph nodes and a transient and limited extravasation in the intestinal mucosa were also observed. Increases in aspartate aminotransferase, alkaline phosphatase and creatine phosphokinase were transient with normal levels restored by day 9. These enzyme increases were accompanied by epithelial hypertrophy of larger bile ductules in the periportal triads of the liver. The low toxicity profile and high tumor target activity make this novel class of drug a promising chemotherapeutic agent.

Alanine Transaminase↗
PubMed2006

Excited state proton transfer in di-(2-hydroxy-3-formyl-5-tert butyl phenyl) methane and solvent effect.

The proton transfer reaction and the spectroscopic properties of di-(2-hydroxy-3-formyl-5-tert butyl phenyl) methane (HFPM) have been examined in different nonpolar and polar solvents at room temperature and 77 K, by means of absorption, emission and time resolved fluorescence spectroscopy. In the ground state, the primary closed form has been identified in all the nonpolar and polar solvents and the anion is detected only in presence of base in some of the polar solvents. After photoexcitation, the excited state intramolecular proton transfer (ESIPT) is indicated by a large Stokes shifted emission (approximately 10,600 cm-1) in all the nonpolar and polar solvents used, except in water and ethylene glycol (EG). The ESIPT band is likely to be originated from the enol tautomer of the HFPM. Two types of anion and H-bonded complex have been detected in the excited state. In water and EG, only anion and H-bonded complex have been detected in the excited state. At 77 K, HFPM shows phosphorescence in pure ethanol, and in n-hexane in presence of triethylamine. It has been suggested that the appearance of phosphorescence is due to the rotation of the formyl group. The measured nonradiative decay rates have always been found to dominate in the decay processes of the excited state of HFPM. Some semiempirical calculations have been undertaken to rationalize the experimental findings.

Butanes↗
PubMed2005

Proton transfer reaction of a new orthohydroxy Schiff base in some protic and aprotic solvents at room temperature and 77 K.

The ground and excited state proton transfer reactions of a new orthohydroxy Schiff base, salicylidine-3,4,7-methyl amine (SMA) has been studied by means of absorption, emission and time resolved fluorescence spectroscopy in some polar protic and aprotic solvents at room temperature and 77K. The spectral behavior of SMA has been investigated both in neutral and basic conditions. The intramolecularly hydrogen bonded enol and zwitterion have been detected in pure methanol and ethanol, the anion is detected in basic condition. At 77K, SMA shows phosphorescence in pure methanol and ethanol. From nanosecond measurements and quantum yields of fluorescence, we have estimated the decay rates of proton transfer reaction in methanol and ethanol.

Hydrogen Bonding↗
PubMed2005

The effect of oral clarithromycin on health status and sputum bacteriology in stable COPD.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterised by airway inflammation, poor health status and recurrent infective exacerbations. Macrolide antibiotics have been shown to improve symptoms and exacerbation rate in chronic lung disease, particularly cystic fibrosis (CF) and diffuse pan-bronchiolitis. The effect of long-term oral clarithromycin on health status, sputum bacterial numbers and exacerbation rate in subjects with clinically stable COPD is undetermined. METHODS: Subjects with moderate-to-severe COPD were recruited into a prospective, double-blind, randomised-controlled trial of 3-months oral clarithromycin (Klaricid XL) or placebo once-daily. The effect of clarithromycin on health status (St. George respiratory and Short Form-36 questionnaires), sputum quantitative bacterial numbers and exacerbation rate were investigated. RESULTS: Sixty-seven subjects (46 males) were recruited; 31 and 36 subjects received clarithromycin and placebo, respectively. There were 7(10%) withdrawals. Compared to placebo, clarithromycin did not significantly improve health status, sputum bacterial numbers, or exacerbation rate. CONCLUSIONS: Three months of oral clarithromycin given to subjects with stable COPD does not improve health status, sputum bacterial numbers or exacerbation rate. Treatment of COPD with clarithromycin during the clinical stable state yields no clinical advantages and therefore cannot be recommended as means of eliminating sputum bacteria or preventing infective exacerbations.

Administration, Oral↗
PubMed2005

Hypoparathyroidism in systemic lupus erythematosus.

We present the case of a man diagnosed with lupus and hypoparathyroidism. This combined diagnosis has very rarely been reported, which is surprising given the evidence that idiopathic hypoparathyroidism can be due to autoimmunity, the multiplicity of organ systems that lupus can affect and the evidence that other endocrinopathies such as hypothyroidism do occur at increased rates in patients with lupus. Hypoparathyroidism does not always cause overt clinical symptoms but the resultant hypocalcemia be a significant health risk. In addition to presenting the case, we review the relevant literature and offer a discussion.

Humans↗
PubMed2004

Interaction between methyl glyoxal and ascorbic acid: experimental and theoretical aspects.

The absorption spectral change of methyl glyoxal (MG) due to the interaction with ascorbic acid (AA or Vitamin C) has been investigated using steady-state spectroscopic technique. A plausible explanation for the spectral change has been discussed on the basis of hydrogen bonding interaction between the two interacting species. The equilibrium constant for the complex formation due to hydrogen bonding interaction between MG and AA has been obtained from absorption spectral changes. Ab inito calculations with DFT B3LYP/6/31G (d,p) basis sets have been used to find out the molecular structure of the hydrogen bonded complex. The O...H distance found in the O-H...O hydrogen bond turns out to be quite short (1.974 A) which is in conformity with the large value of the equilibrium constant determined experimentally.

Ascorbic Acid↗
PubMed2004

Thymidylate synthase as an oncogene?

A surprising finding in the report by Rahman et al. in this issue of Cancer Cell is that forced overexpression of human thymidylate synthase transforms immortalized murine cells into a malignant phenotype. We discuss the possibility that elevated levels of thymidylate synthase noted in some human malignancies may contribute to tumor progression and may also reflect increased levels of its transcriptional activator E2F-1.

Animals↗
PubMed2004

Molecular pathology of haemophilia B: identification of five novel mutations including a LINE 1 insertion in Indian patients.

Heterogeneous mutations in factor IX (FIX) gene cause haemophilia B and a large number of mutations have been characterized. However, reports on gene defects among Indian haemophilia B patients are rare despite a high estimate of such patients in the country. We report identification of 22 independent mutations including five novel mutations in 24 unrelated patients. The novel gene defects include two point mutations, two deletions and one insertion of a LINE 1 element. Majority of the mutations (14 of 24) occurred on the same haplotype background, but do not suggest any founder effect. Direct identification of mutations can be utilized to perform the carrier detection and prenatal diagnosis, especially in families with isolated patients.

Base Sequence↗
PubMed2004

Impact of sputum bacteria on airway inflammation and health status in clinical stable COPD.

Chronic obstructive pulmonary disease (COPD) is characterised by sputum production, bacterial colonisation, neutrophilic bronchial airway inflammation and poor health status. The aim of this study was to determine the impact of sputum potentially pathogenic microorganisms (PPMs) on bronchial airway inflammation, health status and plasma fibrinogen levels in subjects with moderate-to-severe COPD during the clinical stable state. Sputum total cell and neutrophil counts, supernatant interleukin-8, leukotriene B4, tumour necrosis factor-alpha and neutrophil elastase levels, neutrophil chemotaxis and plasma fibrinogen levels were estimated. Health status was determined using the St George's Respiratory Questionnaire and the 36-item Short-Form Health Survey questionnaire. Twenty-seven (40%) subjects had PPMs and 40 (60%) non-PPMs in their sputum. Both groups were of similar age, body mass index, smoking history and lung function. The PPMs group showed significantly higher levels of interleukin-8, leukotriene B4, tumour necrosis factor-a, neutrophil elastase and increased neutrophil chemotaxis. They also exhibited worse health status and raised plasma fibrinogen levels compared to the non-PPMs group. In conclusion, subjects with clinically stable moderate-to-severe chronic obstructive pulmonary disease who had potentially pathogenic microorganisms in their sputum demonstrated an exaggerated airway inflammatory response, poorer health status and increased plasma fibrinogen levels than those who had nonpotentially pathogenic microorganisms.

Aged↗
PubMed2004

Effect of tight glycaemic control on fetal complications in diabetic pregnancies.

AIMS: To find the incidence of fetal complications in Indian diabetic mothers with tight glycaemic control (TC), its comparison with other levels of glycaemic control, i.e., acceptable control (AC), uncontrolled (UC), and relevant international data. METHODS: A total of 240 mothers with diabetes mellitus (DM) and pregnancy were risk-matched and selected from the Antenatal Clinic of NRS Medical College, 176 of whom had gestational diabetes mellitus (GDM) and 64 had pregestational diabetes mellitus (PGDM), and were put on exercise, diet and or insulin therapy. Glycaemic parameters monitored include fasting plasma glucose (FPG), 2 hr. postprandial plasma glucose (PPPG) and HbA1C. TC had - FPG < 70 mg/dl, PPPG < 100 mg/dl, HBA1C < 6.5%; AC with FPG 70-95 mg/dl, 2 hr. PPPG 100-120, HBA1C 6.5-7.5% and UC had FPG > 95 mg/ dl, 2 hr. PPPG > 120 mg/dl and HBA1C > 7.5%. Fetal parameters monitored included large-for-date babies (LGA), small-for-date babies (SFD), birth asphyxia, perinatal death, neonatal hypoglycemia, neonatal hypocalcaemia and congenital anomalies. RESULTS: (i) LGA-AC had the best results (0% vs. 12.5 and 22.29%); (ii) SFD-TC and AC had worst results (16.7% and 18.18% vs. 0%); (iii) Birth asphyxia-AC fared worse 18.18% vs. 4.16% and 0%; (iv) perinatal death and congenital anomalies showed significant reduction with tight control (4.16% and 0% respectively); (v) Neonatal hypoglycemia is lowered in TC compared with UC while neonatal hypocalcaemia does not show any alteration. For PGDM patients there is little intra-group variability of the parameters. The UC subgroups of GDM fared better than PGDM as far as all complications and congenital anomalies were concerned. Compared with international data, there is a dichotomy of the results of GDM and PGDM. CONCLUSION: For GDM patients all parameters may not be uniformly affected by the same degree of glycaemic control. A tight control may not be theonly factor to decide on the outcomes for PGDM patients.

Adolescent↗
PubMed2003

Excited state complex formation between methyl glyoxal and some aromatic bio-molecules: a fluorescence quenching study.

Fluorescence quenching of some important aromatic bio-molecules (ABM) such as 3-aminophthalhydrazide (luminol), tryptophan (Try), phenylalanine and tyrosine (Tyr) by methyl glyoxal (MG) has been studied employing different spectroscopic techniques. The interaction of MG with ABM in the excited state has been analysed using Stern-Volmer (S-V) mechanism. In the case of MG-luminol system time correlated single photon counting (TCSPC) technique has also been applied to explain the S-V mechanism. The bimolecular rate constants obtained are found to be higher than the rate constant for diffusion controlled process. A plausible explanation of the quenching mechanism has been discussed on the basis of hydrogen bonding, charge transfer and energy transfer interaction between the colliding species.

Amino Acids↗
PubMed2002

The prognostic significance of the tumour infiltrating lymphocyte count in stage I testicular seminoma managed by surveillance.

The degree of lymphocytic infiltration is a significant determinant of outcome for a variety of malignancies, but its role in seminoma is unknown. 150 men with stage I testicular seminoma presenting between 1981 and 1993 were managed by surveillance following orchidectomy. The presence of tumour infiltrating lymphocytes (TILs) in each case was classified as high, intermediate or low. At a median follow-up of 9.4 years, 30 of the 150 men developed recurrent seminoma. On univariate analysis, the risk of relapse was associated with age < or =33 years (P=0.002), tumour diameter >6 cm (P=0.03), lymphatic or vascular invasion (P=0.04), tumour invasion of rete testis (P=0.05), and lower TIL count (P=0.02). On multivariate analysis, statistically significant predictors of risk of relapse were age < or =33 years (hazard ratio (HR) 4.6 (95% confidence intervals (CI): 1.7-12.2)) and tumour diameter >6 cm (HR 2.8 (CI: 1.2-6.5)). Lower TIL count was of borderline statistical significance (HR 1.8 (CI: 0.96-3.44)). The functional role of the lymphocytic infiltrate in testicular seminoma warrants further study.

Adult↗
PubMed2002

Prevalence of methicillin-resistant Staphylococcus aureus colonization in surgical patients, on admission to a Welsh hospital.

Nosocomial infection with methicillin-resistant Staphylococcus aureus (MRSA) is on the increase and expensive to treat. Because surgical wound infection is one of the most frequent MRSA-induced infections with often disastrous consequences, it was decided to estimate the incidence and risk factors of MRSA colonization in surgical patients. All patients admitted to general surgical and orthopaedic wards were studied prospectively. At the time of admission, a detailed questionnaire was completed, nasal swabs and swabs of any pre-existing wound sites in each patient were sent for culture. Of 430 patients studied, 23 patients were positive for MRSA on admission. The prevalence of MRSA colonization in this study was 5.3% of whom 15 (65%) were nasal carriers and eight (35%) had MRSA colonization elsewhere. All nasal MRSA carriers had at least one documented hospital admission in the preceding year. Among the MRSA-positive patients, 10 (43%) either were admitted directly from, or had been previously admitted to, a nursing home. MRSA remains mainly a hospital-acquired infection although a significant proportion is acquired in the community. The risk factors identified were previous hospital admission, patients from nursing homes, male and aged over 70.

Adult↗
PubMed2002

Optically stimulated luminescence signals of polymineral fine grains in the JSC Mars-1 soil simulant sample.

The results of various experiments which characterise the optically stimulated luminescence (OSL) signals from polymineral fine grains of a Martian soil simulant sample (JSC Mars-1) are presented. The blue-green stimulated luminescence signal has greater thermal stability than the infrared stimulated luminescence signal for pre-heat temperatures between 250 degrees C and 400 degrees C. Fading tests over a 2 month storage period at 20 degrees C indicate that in some aliquots of JSC Mars-1 both the blue-green stimulated luminescence and the infrared stimulated luminescence signals fade by as much as 50%, whereas in others there is no evidence of significant fading. Dose recovery experiments demonstrate that equivalent dose (measured/given) ratio varies from aliquot to aliquot, and the underestimation in dose is less than 5% for at least one aliquot, for both the infrared and blue-green stimulated luminescence signals.

Luminescent Measurements↗
PubMed2002

Optical dating of palaeochannel deposits in the Riverine Plain, southeastern Australia: testing the reliability of existing thermoluminescence dates.

We present the first quartz optically stimulated luminescence (OSL) ages for palaeochannel sediments from the Riverine Plain in southeastern Australia. For young fluvial sediments, we agree with the notion that analysis of the leading edge of a dose distribution curve provides an objective method for determining the OSL age. For a modern flood deposit (less than 200 years old), the OSL ages estimated using the leading edge method (250 +/- 50 years) and by using the lowest 5% of the measured dose in single aliquots (230 +/- 50 years) agree within experimental errors. For older sediments, we suggest that the mean estimate of the dose distribution is likely to provide a reliable estimate of the OSL age. The luminescence ages suggest that the Coleambally and Kerarbury palaeochannel systems were active between 105 and 80 ky and 55 and 35 thousand years ago; the Yanco palaeochannel system could have been active as recently as 9000 years ago.

Australia↗
PubMed2002

Dose and dose-rate dependence of optically stimulated signals in quartz: theoretical simulations.

In a recent paper Bailey proposed a general model to describe many optically stimulated luminescence (OSL) and thermoluminescence properties of natural quartz. This model consists of five electron trapping centres and four recombination centres: one of the recombination centres is assumed to be radiative and the remaining non-radiative. This paper investigates some additional aspects of the Bailey model. Firstly, the single-aliquot regenerative-dose (SAR) method has been simulated using the model. It is shown that the simulated natural dose (2 Gy) given to the 'sample' in the simulation can be estimated to within approximately 2% using the SAR method. Furthermore, sensitivity-corrected OSL growth curves have been calculated over a dose range of 0 to 2500 Gy. Using the model, it is also demonstrated that the shape of the sensitivity-corrected OSL growth curve is independent of dose rate, for dose rates of 0.001 Gy x s(-1) and 0.1 Gy x s(-1), over a dose range of 0-500 Gy.

Computer Simulation↗