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D Roy

Publications and source records attributed to D Roy.

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

Tinnitus: an update.

Tinnitus is the perceived sensation of sound in the absence of acoustic stimulation. It is the commonest otological disorder referred to either the general practitioner or ear-nose-throat surgeon. This short review examines prevalence, aetiology, associated clinical symptoms, investigations and management. Despite current usage of a vast number of treatment modalities there remains no specific cure for the condition. However, there is currently great emphasis on tinnitus retraining therapy (TRT) in its management. The applications and results of TRT have, indeed, been encouraging--and are also briefly discussed here.

Drug-Related Side Effects and Adverse Reactions↗
PubMed2002

Citation analysis of otorhinolaryngology journals.

Bibliometric analysis is used to assess the 'impact' of scientific journals. The commonest method of evaluation is impact factor. The aim of this study was to analyse the citation data for otorhinolaryngology journals of the years 1994 to 1998. Data on the total number of citations and impact factor of journals was obtained from the CD-ROM editions 1994-98 of the Journal Citation Reports and 'Web of Science' database. The adjusted impact factor and five-year impact factor has been calculated. Fifteen otorhinolaryngology journals have been identified and ranked according to the impact factor. Head and Neck has the highest adjusted impact factor. Archives of Otolaryngology - Head and Neck Surgery has the highest five-year impact factor. There is considerable variation in the ranking of journals calculated by the five-year impact factor. Impact factors of otolaryngology journals can help to direct readers to those journals that have a track record of publishing data that are frequently cited. Although there are several limitations to the use of citation data to rank journals, the authors recommend the use of the five-year period for calculation of the impact factor for ranking of otolaryngology journals.

Bibliometrics↗
PubMed2002

A century of citation classics in otolaryngology-head and neck Surgery journals.

The Science Citation Index (SCI) was introduced primarily as a method of information retrieval but has also been used an objective measure of the quality of an article. Citation classics have been described as papers that have been cited 100 times or more. The aim of this study was to identify the articles published during the 20th century in otolaryngology-head and neck surgery journals that have achieved classic citation status and to present an analysis of this data. Using a database provided by the Institute of Scientific Information (Philadelphia, PA), an assessment was performed of all articles cited 100 or more times in one of the 28 clinical otolaryngology-head and neck journals indexed by the annual Journal Citation Reports. The data were based on citation counts using the 1900 through 1999 Science Citation Index. Institutions located in 10 different countries produced 80 noteworthy articles. The most-cited paper achieved a citation score of 406 and there were 11 articles cited on more than 200 occasions. All of the articles were published in eight journals. The earliest identified publication was in 1933 and the most recent was published in 1993. Twenty authors were involved in two articles and four authors were associated with three classic citations. This paper confirms that analysing citation classics reveals a partial insight into advances and historical developments in the specialty during the last century.

Bibliometrics↗
PubMed2002

Production of oligosaccharides in yogurt containing bifidobacteria and yogurt cultures.

Yogurts were prepared by using yogurt cultures combined to mixed cultures of bifidobacteria (Bifidobacterium animalis, Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium infantis, and Bifidobacterium longum) and by adding a preincubation step (1.5 h at 50 degrees C) with bifidobacteria to the conventional method of manufacture in order to produce oligosaccharides. The survival of bifidobacteria was drastically affected during storage of yogurts, except for products containing B. animalis, in which viable counts remained at >10(6) cfu/g after 28 d of storage at 4 degrees C. Oligosaccharides with a degree of polymerization of 3 were produced during the preincubation step (0.31 to 0.68%), and the amount in the final products varied according to the species of bifidobacteria inoculated during the preincubation step or the concentration of bifidobacteria used as second inoculum during the fermentation process. In fact, the higher concentration of oligosaccharides measured at the end of the fermentation process (0.72%) and the 28 d-storage period (0.67%) was obtained for yogurts containing B. infantis. However, yogurts containing B. breve showed higher beta-galactosidase activities and had lower lactose concentrations after the fermentation process and the storage period than the other yogurts. The use of a mixed cultures of bifidobacteria (B. animalis, B. infantis, or B. breve) thus allows the production of yogurts in which bifidobacteria can survive in relatively high cell numbers and contain appreciable amount of oligosaccharides.

Bifidobacterium↗
PubMed2002

Prospective evaluation of modified Alvarado score for diagnosis of acute appendicitis.

Modified Alvarado scoring system was evaluated regarding its usefulness in the early diagnosis of acute appendicitis and in reduction of the incidence of negative appendicectomies. One hundred and ten patients with a provisional diagnosis of acute appendicitis were studied prospectively at R G Kar Medical College and Hospital, Calcutta over a period of 10 months. High score was found to be a dependable aid both in the pre-operative diagnosis of acute appendicitis and in the reduction of negative appendicectomies in men and children but the same was not true for women who had a high false positive rate for acute appendicitis.

Acute Disease↗
PubMed2001

Dielectric relaxation in a single tryptophan protein.

Although dielectric relaxation can significantly affect the intrinsic fluorescence properties of a protein, usually it is fast compared to fluorescence timescales and needs to be slowed down by adding viscogens or lowering temperature before its impact on fluorescence can be studied. We report here a remarkable blue shift in fluorescence upon bimolecular quenching in the single-tryptophan thermostable protein Bj2S, the 2S seed albumin from Brassica juncea, at ambient temperature and viscosity. The magnitude of the blue shift ( approximately 5 nm at 50% quenching by acrylamide) is striking in a single-tryptophan protein and is attributed to a slowly relaxing dielectric environment in Bj2S from red edge excitation, steady-state polarization and time-resolved fluorescence experiments. Our results have important implications on interpretation of fluorescence of proteins with highly constrained backbones and in designing model systems for studying slow protein solvation dynamics using Trp fluorescence as the reporter probe.

Albumins↗
PubMed2001

The inhibition of DNA repair capacity by stilbene estrogen in Leydig cells: its implications in the induction of instability in the testicular genome.

In this study, we examined the effect of stilbene estrogen, diethylstilbestrol (DES), on the DNA repair capacity of mouse Leydig cells using the host cell reactivation assay. Cells transfected with UV-damaged plasmids, undamaged plasmids, or no plasmids (sham treatment) were grown in serum, serum-free, or DES plus serum-free medium. The serum-grown cells which have a shorter cell cycle time (16h) showed a 40% decrease in DNA repair capacity when compared to serum-free cells with a longer cell cycle time (25h). A significant decrease in the DNA repair capacity of the Leydig cells exposed to DES was observed compared to untreated cells grown in a serum-free environment (P<0.05). The effect of DES on DNA repair in Leydig cells was dose dependent. We have recently shown that DES stimulates the growth of Leydig cells. Stimulatory growth of Leydig cells coupled with a decrease in DNA repair capacity by DES may allow the accumulation of mutagenic lesions in DNA. The mutagenic lesions may result from the attack of redox cycling products of DES and/or errors of replication. This, in turn, may produce alterations in the genome of Leydig cells resulting in genetically unstable cells that may serve as precursor cells for testicular carcinogenesis.

Animals↗
PubMed2001

Media for the isolation and enumeration of bifidobacteria in dairy products.

Bifidobacteria are commonly used for the production of fermented milks, alone or in combination with other lactic acid bacteria. Bifidobacteria populations in fermented milks should be over 10(6) bifidobacteria/g at the time of consumption of strain added to the product. Hence, rapid and reliable methods are needed to routinely determine the initial inoculum and to estimate the storage time period bifidobacteria remain viable. Plate count methods are still preferable for quality control measurements in dairy products. It is, therefore, necessary to have a medium that selectively promotes the growth of bifidobacteria, whereas other bacteria are suppressed. The present paper is an overview of media and methods including summaries of published comparisons between different selective media. Culture media for bifidobacteria may be divided into basal, elective, differential and selective culture medium. Non-selective media are useful for routine enumeration of bifidobacteria when present in non-fermented milks. Reinforced Clostridial Agar and De Man Rogosa Sharpe (MRS) supplemented with cysteine and agar available commercially are the media of choice for industrial quality control laboratories. Several media for selective or differential isolation have been described for enumeration of bifidobacteria from other lactic acid bacteria. From the large number of selective media available, it can be concluded that there is no standard medium for the detection of bifidobacteria. However, Columbia agar base media supplemented with lithium chloride and sodium propionate and MRS medium supplemented with neomycin, paromomycin, nalidixic acid and lithium chloride can be recommended for selective enumeration of bifidobacteria in dairy products.

Animals↗
PubMed2001

Identification of novel breast tumor-specific mutation(s) in the q11.2 region of chromosome 17 by RAPD/AP-PCR fingerprinting.

Analysis of genetic instability in breast cancer tissues compared to uninvolved breast tissues from the same individuals by RAPD (random amplified polymorphic DNA)/AP-PCR (arbitrarily primed PCR) fingerprinting using 30 arbitrary primers revealed 190 amplified DNA fragments. Presumably, each of these represents a gene locus in a different region of the genome of breast cancer tissues. Among these amplified DNA fragments, 65 (34.2%) exhibited presence and absence or reductions and enhancements in the intensity in breast cancer tissues compared to uninvolved breast tissues from the same individuals, and 11 amplified DNA fragments (5.7%) represented polymorphisms in the uninvolved human breast tissues. Reductions and enhancements in the intensity of some of the amplified fragments were observed indicating allelic gains or losses in the breast tumor genome compared to the matched uninvolved tissue genome. The presence or absence of some of the amplified DNA fragments were observed in this study indicating homozygous deletions or insertions in the breast tumor DNA compared to the matched uninvolved tissue DNA. Notably, an insertion of a 1270 bp amplified fragment was observed in 81% (17 of 21) of the tumor samples using the primer, OPC04. This amplified fragment resolved into two, 1200 and 1300 bp, single-stranded amplified fragments on the denaturing sequencing gel. This separation into single-stranded fragments suggests that the amplified fragment contains a conformation that is semistable. The 1270 bp amplified fragment localizes to the q11.2 region of chromosome 17. Sequence analysis of this fragment showed a significant DNA base sequence similarity (93%) with one of the breast tumor-specific human EST. The similarity with EST sequences and RT-PCR analysis showed that a part of this amplified fragment is from the coding region of the genome. Any one of the events observed in this study could play an important role in the development of breast cancer or could occur during the clonal expansion of the genetically unstable breast cells.

Breast Neoplasms↗
PubMed2001

Profiling of differentially expressed genes induced by high linear energy transfer radiation in breast epithelial cells.

Methods to define patterns of gene expression have applications in a wide range of biological systems. Several molecular biological techniques are used to study expression patterns during the neoplastic progression of breast epithelial cells. In the present study, differential expression of human oncogenes/tumor suppressor genes in human breast epithelial cell lines irradiated with low doses of high linear energy transfer radiation and treated with estrogen was assessed with cDNA expression arrays. Transformed and tumorigenic cell lines were compared with the control cell line to identify differentially expressed genes during tumorigenic progression. Autoradiographic analysis showed that of the 190 genes analyzed, 49 genes showed a high level of altered expression, and 12 genes had minor differences in expression levels. Among these 49 genes, 17 genes were altered at all stages of transformation, 21 were altered only at the early stage, and the remaining 11 were at the late stage of transformation to the tumorigenic stage of progression. Among the 11 late stage-associated genes, seven genes were altered exclusively in the tumorigenic cell lines and in Tumor-T. Of the 17 all-stage genes, six were randomly selected, and we confirmed their altered expression by gene-specific semiquantitative reverse transcription polymerase chain reaction, followed by Northern blot analysis. The results showed that the mRNA expression patterns of all these genes were consistent with the expression pattern seen on the array. Among these six genes, five genes, including c-myc, puf, MNDA, c-yes, and Fra-1 showed upregulation, and the other gene, RBA/p48, showed downregulation in the transformed and tumorigenic cell lines compared with the control MCF-10F cell line. Investigation of these genes should help establish the molecular mechanisms of progression that are altered by radiation and estrogen treatment. A number of candidates reported here should be useful as biomarkers involved in breast carcinogenesis.

Alpha Particles↗
PubMed2001

Molecular discrimination of lactobacilli used as starter and probiotic cultures by amplified ribosomal DNA restriction analysis.

Lactic acid bacteria such as Lactobacillus helveticus, L. delbrueckii subsp. delbrueckii, L. delbrueckii subsp. lactis, L. delbrueckii subsp. bulgaricus, L. acidophilus, and L. casei related taxa which are widely used as starter or probiotic cultures can be identified by amplified ribosomal DNA restriction analysis (ARDRA). The genetic discrimination of the related species belonging to these groups was first obtained by PCR amplifications by using group-specific or species-specific 16S rDNA primers. The numerical analysis of the ARDRA patterns obtained by using CfoI, HinfI, Tru9I, and ScrFI was an efficient typing tool for identification of species of the L. acidophilus and L. casei complex. ARDRA by using CfoI was a reliable method for differentiation of L. delbrueckii subsp. bulgaricus and L. delbrueckii subsp. lactis. Finally, strains ATCC 393 and ATCC 15820 exhibited unique ARDRA patterns with CfoI and Tru9I restriction enzymes as compared with the other strains of L. casei, L. paracasei, and L. rhamnosus.

Base Sequence↗
PubMed2001

Molecular alterations in tumorigenic human bronchial and breast epithelial cells induced by high LET radiation.

Carcinogenesis is a multi-stage process with sequence of genetic events governing the phenotypic expression of a series of transformation steps leading to the development of metastatic cancer. In the present study, immortalized human bronchial (BEP2D) and breast (MCF-10F) cells were irradiated with graded doses of either 150 keV/micrometer alpha particles or 1 GeV/nucleon 56Fe ions. Transformed cells developed through a series of successive steps before becoming tumorigenic in nude mice. Cell fusion studies indicated that radiation-induced tumorigenic phenotype in BEP2D cells could be completely suppressed by fusion with non-tumorigenic BEP2D cells. The differential expressions of known genes between tumorigenic bronchial and breast cells induced by alpha particles and their respective control cultures were compared using cDNA expression array. Among the 11 genes identified to be differentially expressed in BEP2D cells, three (DCC, DNA-PK and p21(CIP1)) were shown to be consistently down-regulated by 2 to 4 fold in all the 5 tumor cell lines examined. In contrast, their expressions in the fusion cell lines were comparable to control BEP2D cells. Similarly, expression levels of a series of genes were found to be altered in a step-wise manner among tumorigenic MCF-10F cells. The results are highly suggestive that functional alterations of these genes may be causally related to the carcinogenic process.

Alpha Particles↗
PubMed2001

Comparison of fentanyl and sufentanil in combination with bupivacaine for patient-controlled epidural analgesia during labor.

STUDY OBJECTIVES: To compare the efficacy of fentanyl plus bupivacaine with sufentanil plus bupivacaine for treatment of pain during labor and delivery using patient-controlled epidural analgesia (PCEA). DESIGN: Prospective, double-blind, clinical investigation. SETTINGS: University-affiliated hospital. PATIENTS: 226 ASA physical status I and II laboring patients. INTERVENTIONS: Patients were randomized to receive 0.125% bupivacaine with fentanyl (2 micro g.ml(-1)) or 0.125% bupivacaine with sufentanil (0.25 micro g.ml(-1)) through PCEA. MEASUREMENTS: Maternal analgesia assessed by visual analog scale was recorded before epidural block, 1 and 3 hours after epidural block, at full cervical dilation, and at delivery. Motor blockade assessed by Bromage scale was recorded at delivery. MAIN RESULTS: Nine patients in group fentanyl, and 11 in group sufentanil were excluded from the study. Overall analgesia was good and no difference was observed between the two groups. Total boluses of 4 mL bupivacaine-opioid administered and the number of supplementary top-up injections of 5 mL 0.25% bupivacaine were similar in both groups. In group sufentanil, motor blockade and pruritus were significantly lower than in group fentanyl. Nausea was not recorded in any patients. Mode of delivery was similar in both groups, i.e., cesarean section, vacuum or forceps, or spontaneous vaginal delivery. No difference was observed in Apgar scores. CONCLUSIONS: Sufentanil is preferable to fentanyl during bupivacaine PCEA as there is less incidence of motor blockade and pruritus.

Adult↗
PubMed2001

Publication rates of scientific papers presented at the Otorhinolarygological Research Society meetings.

The aim of this study was to determine the publication rate of scientific papers in peer review journals presented at the Otorhinolarygological Research Society (ORS) meetings from 1978 to 1995 inclusive. The abstracts of the presentations at ORS meetings are published in Clinical Otolaryngology. A MEDLINE search was performed on abstracts presented at ORS meetings from 1978 to 1995 using both authors and key words within the text of the abstract. The publication rate, journal of publication, time to publication, change in contents, change in authors and change in conclusions of abstracts were tabulated. The publication rate for papers presented at ORS meetings from 1978 to 1995 was 69.09%. The average time to publication was 22.5 months. Papers derived from the ORS abstracts were most commonly published in Clinical Otolaryngology (34%) and Journal of Laryngology and Otology (18.64%). The results indicate that nearly 69% of presented material at the biannual ORS meetings eventually get published in peer reviewed journals. This compares favourably with publication rate of other specialities.

Bibliometrics↗
PubMed2001

Atrioventricular interval optimization and exercise tolerance.

Modern pacemakers offer many programming options regarding the AV interval including the ability to vary AV intervals depending on whether atrial activity is paced or spontaneous and to shorten AV intervals with increasing rates. To determine if optimization of these features improves exercise tolerance, 14 patients with intact sinus node function and AV block treated with dual chamber pacemakers were enrolled in a randomized double-blind crossover trial. Doppler echocardiographic measurements of cardiac index and mitral flow were assessed over a range of programmable AV intervals at rest to determine each patient's optimal AV interval. Eleven patients completed serial graded exercise tests with spiroergometry after randomly programming the AV interval three ways in a crossover manner: fixed AV interval = 150 ms without rate adaptation (150/Fixed), fixed AVinterval = 150 ms with rate adaptation (150/R), or optimized AV interval with rate adaptive AV interval shortening (optimized/R). Exercise capacity was determined by maximum oxygen uptake. Ten men and four women, age 64 +/- 8 years, were enrolled. At rest, optimization of the AVintervalimproved the cardiac index by 21% (P < 0.001) and mitral flow by 13.4% (P < 0.001) when compared to least-favorable AV intervals. During exercise, no differences in maximum heart rates were noted. Maximum oxygen uptake was increased in both groups with rate adaptive AVinterval shortening when compared tofixed AVinterval without rate adaptation: 13.9% (adjusted P < 0.04) and 14.6% (adjusted P < 0.02) in optimized/R and 150/R, respectively. No differences were noted between optimized/R and 150/R. In conclusion, rate adaptive AV interval shortening improved exercise tolerance independent of changes in heart rate. However, optimization of the AV interval with Doppler echocardiography at rest did not further improve exercise capacity.

Atrial Function↗
PubMed2001

Catheter cryoablation of the atrioventricular node in patients with atrial fibrillation: a novel technology for ablation of cardiac arrhythmias.

INTRODUCTION: Recent animal studies demonstrated the feasibility and safety of applying percutaneous catheter cryoablation technology for ablation of arrhythmogenic sites. The studies also showed that reversible "ice mapping" can be performed before creating permanent lesions. We investigated the feasibility and safety of applying this new technology in man. METHODS AND RESULTS: Cryoablation of the AV node (AVN) using a 9-French quadripolar catheter with a 4-mm electrode tip was attempted in 12 patients (mean age 67.8 +/- 11.4 years) with refractory atrial fibrillation. Whereas technical issues prevented adequate tissue contact in two patients, complete AVN block was obtained in the remaining 10 patients after 4.8 +/- 1.9 cryoapplications lasting 5.5 +/- 0.2 minutes resulting in temperatures of -58.1 degrees +/- 5.4 degrees C. In all patients with sinus rhythm at the time of the procedure, cryomapping at warmer temperatures induced reversible AVN block and allowed confirmation of a successful site before definitive ablation. Intracardiac echocardiography was performed in three patients and allowed visualization of the cryocatheter-endocardial contact and cryolesion formation. No major procedural complications were reported. After 6 months of follow-up, 8 of 10 initially successful patients remained in complete block; 1 had partial recovery of AVN conduction manifested by atrial fibrillation with a slow ventricular response, and 1 fully recovered AVN conduction. CONCLUSION: (1) Catheter cryoablation of the AVN can be performed safely in man. (2) Reversible cryomapping is feasible and may offer an advantage over radiofrequency ablation. (3) Cryocatheter-endocardial contact and cryolesion growth can be monitored with intracardiac echocardiography.

Aged↗