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Biomedical subjects

A Banerjee

Publications and source records attributed to A Banerjee.

At least 55 records · Page 3Linked to original sources
PubMed2002

The effect of GMC guidelines on the length of otolaryngological out-patient clinics in a district general hospital.

The British Association of Otolaryngologists has laid down guidelines on the length of time that should be allocated to an out-patient consultation. The General Medical Council (GMC) has also produced guidelines as to what is to be discussed with a patient during an out-patient consultation. This study was designed to determine what effect adhering to the GMC's guidelines would have on the length of an out-patient consultation. Out-Patient consultations were timed for patients referred with common otolaryngological complaints. The study was then repeated after the researchers had been given specific instructions on what to discuss with the patients to comply with the GMC guidelines. Consultation times more than doubled after application of the GMC guidelines. This study highlights the difficulty of specifically adhering to guidelines from our regulatory body, while attempting to fulfil the demands for consultations, with the existing manpower levels available.

Appointments and Schedules↗
PubMed2002

Acute renal failure and metabolic disturbances in the short bowel syndrome.

BACKGROUND: Short bowel syndrome (SBS) describes a malabsorptive state caused by extensive loss of small intestinal length. AIM: To improve understanding of the metabolic complications of SBS. DESIGN: Observational study of five patients with SBS who presented with acute renal failure. RESULTS: Acute renal failure in our patients was predominantly due to salt and fluid depletion, and sepsis. Electrolyte imbalance was a major cause of morbidity. Metabolic acidosis was seen in three patients, and may arise from excessive gastrointestinal bicarbonate loss, compounded by impaired renal homeostasis. Our patients also manifested disturbances of calcium and magnesium homeostasis. DISCUSSION: Patients with SBS are at high risk of renal failure. Prevention of this complication requires close monitoring and the maintenance of sodium homeostasis through increased intake and measures to reduce loss (e.g. anti-motility agents and large bowel re-anastomosis), and calcium, magnesium and vitamin D supplementation.

Acute Kidney Injury↗
PubMed2002

CT scanning of middle ear cholesteatoma: what does the surgeon want to know?

The history of surgery for middle ear cholesteatoma is of an evolution of techniques to meet the challenges of inaccessible disease and of post-operative cavity management. The concept has traditionally been of exploration guided by awareness and anticipation of all, possibly asymptomatic, complications. Modern imaging reliably demonstrates surgical anatomy, dictating the ideal approach, forewarns of complications and may reveal the extent of disease. An apparent resistance amongst otologists to universal CT scanning prior to mastoidectomy contrasts with the enthusiasm of skull base surgeons or rhinologists for appropriate imaging.

Cholesteatoma, Middle Ear↗
PubMed2002

Quality assessment of sputum transportation, smear preparation and AFB microscopy in a rural district in Malawi.

SETTING: Ntcheu District, Central Region of Malawi. OBJECTIVES: To assess 1) the feasibility of introducing simple internal quality control procedures for acid-fast bacilli (AFB) microscopy, and 2) the quality of the district sputum smear microscopy service. DESIGN: A simple internal quality control system was piloted in which district laboratory staff assessed: 1) specimen suitability, 2) time between sputum submission and smear examination, 3) smear preparation and staining, and 4) microscopy. Actual times for processing specimens were compared with recommended times. External quality validation was carried out. RESULTS: Of 4805 sputum specimens: 1) documentation was complete in 95%, 2) 93% reached the laboratory within 7 days of collection, 3) 96% of smears were well prepared and stained, and 4) 97% concordance (96.4% smear-positive and 97.6% smear-negative) was demonstrated when 208 smears were re-examined by a second technician. The aggregate index of reliability was 86%. The mean time spent on microscopic examination was 3.8 minutes, compared with the recommended time of 10 minutes. When all smears from 164 patients were assessed externally, 98.2% concordance (98.1% smear-positive and 98.2% smear-negative) was demonstrated. False smear-negative and smear-positive rates were less than 2% each. CONCLUSION: District laboratory staff were able to incorporate simple quality control procedures for AFB microscopy into their routine practice, resulting in a reliable service. The lessons learnt are widely relevant and potentially useful for implementation of a national quality assurance scheme.

Chi-Square Distribution↗
PubMed2001

Conformational properties of alpha-tubulin tail peptide: implications for tail-body interaction.

The carboxy-terminal segments of the alpha/beta-tubulins are flexible regions rich in acidic amino acid residues. It is generally believed that these regions play crucial roles in tubulin polymerization and interaction with many ligands, including colchicine. Exactly how these effects are exerted are not known at present. One such interesting aspect is the pH dependence of colchicine-tubulin interaction and the influence of the alpha-tail on the binding interaction. We have investigated the location of the colchicine-binding site on tubulin by docking. It has been located on the alpha/beta interface on the N-terminal side, which is also supported by much of the solution data. This location is too far from the tail regions, suggesting that influence of the tail region is transmitted by a pH-dependent conformational change. Two-dimensional NMR studies indicate that at pH 7 a 13-residue peptide corresponding to alpha-tubulin tail shows little NOE constraints, suggesting extended conformation. On the contrary, at pH 5, a relatively compact structure was deduced from the interproton NOE constraints. Pulsed field gradient measurement of diffusion constant indicates that the peptide at pH 5 is substantially faster diffusing than at pH 7. The Perrin factors calculated from diffusion data indicates that the peptide structure at pH is significantly more compact than at pH 7. Temperature coefficients of several amide protons at pH 5 fall below 5 ppb/(o)K, indicating a degree of protection. A difference is also seen in the CD spectra obtained at different pHs, consistent with the NMR data. We have investigated the probable spatial organization of the tail of the alpha-subunit of tubulin, in the high pH extended form and the low pH compact form. On the basis of correlation of pH dependence of many properties of tubulin and the conformation of the alpha-tail peptide, we propose that the intrinsic conformational preference of the tail-region modulate the tail-body interaction, which in turn has important bearing on colchicine binding properties.

Binding Sites↗
PubMed2001

First crystallographic signature of amyloid-like fibril forming beta-sheet assemblage from a tripeptide with non-coded amino acids.

The model tripeptide Boc-beta-Ala(1)-Aib(2)-beta-Ala(3)-OMe 1 [beta-Ala: beta-alanine, Aib: alpha-aminoisobutyric acid] forms an infinite parallel beta-sheet structure through intermolecular interactions in single crystals and from the SEM diagram of this peptide, it is evident that the compound has fibrillar morphology, a characteristic of neurodegenerative disease causing amyloid aggregate.

Amino Acids↗
PubMed2001

Insight to structural subsite recognition in plant thiol protease-inhibitor complexes : understanding the basis of differential inhibition and the role of water.

BACKGROUND: This work represents an extensive MD simulation / water-dynamics studies on a series of complexes of inhibitors (leupeptin, E-64, E-64-C, ZPACK) and plant cysteine proteases (actinidin, caricain, chymopapain, calotropin DI) of papain family to understand the various interactions, water binding mode, factors influencing it and the structural basis of differential inhibition. RESULTS: The tertiary structure of the enzyme-inhibitor complexes were built by visual interactive modeling and energy minimization followed by dynamic simulation of 120 ps in water environment. DASA study with and without the inhibitor revealed the potential subsite residues involved in inhibition. Though the interaction involving main chain atoms are similar, critical inspection of the complexes reveal significant differences in the side chain interactions in S2-P2 and S3-P3 pairs due to sequence differences in the equivalent positions of respective subsites leading to differential inhibition. CONCLUSION: The key finding of the study is a conserved site of a water molecule near oxyanion hole of the enzyme active site, which is found in all the modeled complexes and in most crystal structures of papain family either native or complexed. Conserved water molecules at the ligand binding sites of these homologous proteins suggest the structural importance of the water, which changes the conventional definition of chemical geometry of inhibitor binding domain, its shape and complimentarity. The water mediated recognition of inhibitor to enzyme subsites (Pn.H2O.Sn) of leupeptin acetyl oxygen to caricain, chymopapain and calotropinDI is an additional information and offer valuable insight to potent inhibitor design.

Amino Acid Chloromethyl Ketones↗
PubMed2001

Mg2+ is not catalytically required in the intrinsic and kirromycin-stimulated GTPase action of Thermus thermophilus EF-Tu.

The influence of divalent metal ions on the intrinsic and kirromycin-stimulated GTPase activity in the absence of programmed ribosomes and on nucleotide binding affinity of elongation factor Tu (EF-Tu) from Thermus thermophilus prepared as the nucleotide- and Mg(2+)-free protein has been investigated. The intrinsic GTPase activity under single turnover conditions varied according to the series: Mn(2+) (0.069 min(-1)) > Mg(2+) (0.037 min(-1)) approximately no Me(2+) (0.034 min(-1)) > VO(2+) (0.014 min(-1)). The kirromycin-stimulated activity showed a parallel variation. Under multiple turnover conditions (GTP/EF-Tu ratio of 10:1), Mg(2+) retarded the rate of hydrolysis in comparison to that in the absence of divalent metal ions, an effect ascribed to kinetics of nucleotide exchange. In the absence of added divalent metal ions, GDP and GTP were bound with equal affinity (K(d) approximately 10(-7) m). In the presence of added divalent metal ions, GDP affinity increased by up to two orders of magnitude according to the series: no Me(2+) < VO(2+) < Mn(2+) approximately Mg(2+) whereas the binding affinity of GTP increased by one order of magnitude: no Me(2+) < Mg(2+) < VO(2+) < Mn(2+). Estimates of equilibrium (dissociation) binding constants for GDP and GTP by EF-Tu on the basis of Scatchard plot analysis, together with thermodynamic data for hydrolysis of triphosphate nucleotides (Phillips, R. C., George, P., and Rutman, R. J. (1969) J. Biol. Chem. 244, 3330-3342), showed that divalent metal ions stabilize the EF-Tu.Me(2+).GDP complex over the protein-free Me(2+).GDP complex in solution, with the effect greatest in the presence of Mg(2+) by approximately 10 kJ/mol. These combined results show that Mg(2+) is not a catalytically obligatory cofactor in intrinsic and kirromycin-stimulated GTPase action of EF-Tu in the absence of programmed ribosomes, which highlights the differential role of Mg(2+) in EF-Tu function.

Anti-Bacterial Agents↗
PubMed2001

Candidate gene isolation and comparative analysis of a commonly deleted segment of 7q22 implicated in myeloid malignancies.

Monosomy 7 and deletion of 7q are recurring abnormalities in malignant myeloid diseases. Here we extensively characterize an approximately 2-Mb commonly deleted segment (CDS) of 7q22 bounded by D7S1503 and D7S1841. Approximately 1.8 Mb of sequence have been generated from this interval, facilitating the construction of a transcript map that includes large numbers of genes and ESTs. The intron/exon organization of seven genes and expression patterns of three genes were determined, and leukemia samples were screened for mutations in five genes. We have used polymorphic markers from this region to examine leukemia cells for allelic loss within 7q22. Finally, we isolated mouse genomic clones orthologous to several of the characterized human genes. Fluorescence in situ hybridization studies using these clones indicate that a region of orthologous synteny lies on proximal mouse chromosome 5. These resources should greatly accelerate the pace of candidate gene discovery in this region.

Acute Disease↗
PubMed2001

Proper timing of blood cardioplegia in infant lambs: superiority of a multiple-dose regimen.

BACKGROUND: In the pediatric and infant age groups, it is unclear whether repeated infusions of blood cardioplegia solution during ischemic arrest are beneficial or detrimental when compared with a single-dose regimen. METHODS: Twenty lambs (aged 6 to 7 weeks) were placed on cardiopulmonary bypass. A miniature glass-tip electrode measured myocardial pH and hydrogen ion concentration, [H+], in the anterior wall. The aorta was clamped for 2 hours. Group S (n = 10) received a single dose of blood cardioplegia solution. Group M (n = 10) received multiple doses of blood cardioplegia solution at 20-minute intervals. RESULTS: The amount of [H+] generated during the cross-clamp period was greater in group S than in group M (39.2 +/- 10.1 nmol/L versus 0.4 +/- 1.4 nmol/L, p < 0.008). The percent increase in the time constant, tau, an index of diastolic relaxation, was more prolonged after cardiopulmonary bypass in group S when compared with group M (51.4% +/- 2.8% versus 6.4% +/- 3.0%, p < 0.0001). Similarly, the percent decrease in end systolic elastance, a measure of systolic contractility, was greater in group S after cardiopulmonary bypass when compared with group M (29.5% +/- 1.4% versus 7.3% +/- 1.3%, p < 0.0001). CONCLUSIONS: In this infant lamb model, multiple doses of blood cardioplegia solution provided superior metabolic preservation and hemodynamic support after 2 hours of aortic clamping when compared with a single-dose regimen.

Animals↗
PubMed2001

Vancomycin-induced linear IgA disease with autoantibodies to BP180 and LAD285.

Linear IgA disease (LAD) is an acquired autoimmune subepidermal bullous disease characterized by the linear deposition of IgA at the basement membrane zone. A minority of cases are induced by drugs, of which the most frequently implicated is vancomycin. The target antigens in idiopathic LAD are heterogeneous, but have not previously been reported in vancomycin-induced LAD. We report three cases, and in two of these we investigated the target antigens. In both we identified IgA antibodies to LAD285 and IgA and IgG antibodies (dual response) to BP180.

Aged↗
PubMed2001

Comparison of the effects of a cell saver and low-dose aprotinin on blood loss and homologous blood usage in patients undergoing valve surgery.

OBJECTIVE: To compare 2 important techniques of blood conservation, use of a cell saver and low-dose aprotinin, in terms of blood loss and homologous blood usage in patients undergoing cardiac valve surgery. DESIGN: Prospective, randomized. SETTING: Tertiary care hospital. PARTICIPANTS: Sixty adult patients undergoing elective valve surgery. INTERVENTIONS: The patients were divided into 3 groups of 20 each. In group 1, aprotinin in the dose of 30,000 KIU/kg was added to the pump prime, with a further dose of 15,000 KIU/kg added at the end of each hour of cardiopulmonary bypass. In group 2, a cell-saver system was used to collect all blood at the operation site for processing in preparation for subsequent reinfusion. Group 3 patients acted as a control group and underwent routine management, which included collection of autologous blood during the pre-cardiopulmonary bypass period. A hemoglobin of <8 g/dL was considered as an indication for bank blood transfusion in the postoperative period. MEASUREMENTS AND MAIN RESULTS: The chest tube drainage was significantly less in group 1 compared with groups 2 and 3, with total drainage (median [interquartile range]) amounting to 250 mL [105 to 325 mL] vs. 700 mL [525 to 910 mL] in group 2 and 800 mL [650 to 880 mL] in group 3 (p < 0.001). The patients in groups 1 and 2 required significantly less bank blood (median [interquartile range]) as compared with group 3 (350 mL [0 to 525 mL], 350 mL [0 to 350 mL], and 1050 mL [875 to 1050 mL]; p < 0.001), respectively. Cell saver provided 410 +/- 130 mL of hemoconcentrated blood in group 2. The average preoperative hemoglobin concentration was 11.3 g/dL, and it was around 9 g/dL on the 7th postoperative day. The hemoglobin concentration at various stages during hospitalization in all 3 groups was similar. CONCLUSIONS: Low-dose aprotinin and a cell saver are effective and comparable methods of blood conservation. Aprotinin helps by decreasing the postoperative drainage, and a cell saver helps by making the patient's own blood available for transfusion.

Adult↗