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Biomedical subjects

A Banerjee

Publications and source records attributed to A Banerjee.

At least 541 records · Page 30Linked to original sources
PubMedDate not supplied

Tuberculosis in health care workers in Malawi.

Although sub-Saharan Africa has the highest rates of tuberculosis (TB) and human immunodeficiency virus (HIV) infection in the world, the rates of TB amongst its health care workers (HCWs) are poorly documented. We therefore conducted a country-wide investigation. All district/government and mission hospitals in Malawi that diagnose and care for TB patients were visited in order to obtain information on hospital-based HCWs and their incidence of TB in 1996. Hospital TB case loads, country-wide TB notification numbers and national population estimates for 1996 were obtained, which enabled TB case notification rates to be calculated. In 1996, 108 (3.6%) of 3042 HCWs from 40 hospitals were registered and treated for TB: 22 with smear-positive pulmonary TB (PTB), 40 with smear-negative PTB and 46 with extrapulmonary TB. The overall case fatality rate was 24%. Compared with the adult general population aged > or = 15 years, the relative risk [95% confidence interval (CI)] in HCWs of all types of TB was 11.9 [9.8-14.4], of smear-positive PTB 5.9 [3.9-9.0], of smear-negative PTB 13.0 [9.5-17.7] and of extrapulmonary TB 18.4 [13.8-24.6], P < 0.05. The 1996 hospital TB case load ranged from 29 to 915: there were no cases of TB in HCWs in hospitals whose case load was < or = 100 patients, while the TB case rate among HCWs was similar in hospitals with annual case loads of 101-300 or > 300. The annual risk of TB was high among all categories of HCW, especially clinical officers. This study shows a high rate of TB in HCWs in Malawi, and emphasizes the need for practical and affordable control measures for the protection of HCWs from TB in low-income countries.

Adolescent↗
PubMedDate not supplied

A method for the detection and quantification of bacteria in human carious dentine using fluorescent in situ hybridisation.

OBJECTIVES: Previous studies have evaluated bacterial numbers in carious dentine using conventional culturing methods, capable of detecting only a proportion of the total bacteria present within lesions. The aim of this study was to detect and enumerate the total bacterial population present in carious human dentine by means of fluorescent in situ hybridisation. METHOD: Five freshly extracted carious molars were sequentially hand excavated under sterile conditions through four levels in the lesions. Replicate samples were probed with a rhodamine-tagged, 16S rRNA-directed probe (EUB338), specific for the bacterial domain. Two of the five original samples were examined using fluorescence microscopy and by using a systematic visual counting strategy; direct enumeration of the bacterial population in carious dentine was performed. RESULTS: In the superficial, middle and deep/excavation front zones, a mean of 7.34 x 10(6) (standard error of the mean, SEM +/- 0.44), 5.23 x 10(6) (SEM +/- 0.18), and 1.69 x 10(6) (SEM +/- 0.15) total bacteria/mg dentine were found, respectively. In the advancing front zone (beyond the conventional clinical excavation boundary) a mean of 0.34 x 10(6) (SEM +/- 0.05) total bacteria/mg dentine was recorded. CONCLUSION: A bacterial enumeration strategy was developed and detected greater numbers of bacteria through the depth of carious lesions that had been reported previously. The technique could be further developed using species-specific probes to determine the distribution, abundance and viability of all bacteria in carious dentine. This new information in turn will lead to a better understanding of the pathological process of caries and ultimately, its clinical treatment.

Bacteria↗
PubMedDate not supplied

Topological shape and size of peptides: identification of potential allele specific helper T cell antigenic sites.

A database of primary sequences of 28 immunogenic peptides, known to elicit T cell response, derived from five different haplotypes was compiled to identify allele specific helper T cell antigenic sites using a rule based graph-theoretical method. The prediction was based on the identification of allele specific patterns in the form of "topological shape and size" present in the peptides. Indices computed from weighted connected graph models of amino acid side chains and peptides were used in this purpose. The system was trained by 10 Ad and 10 non-Ad restricted peptide sequences, assigned actives and inactives, respectively, chosen randomly from the database, and four Ad and four non-Ad restricted sequences were kept as test peptides. This allowed the system to learn about "topological shape and size" specific for Ad restricted peptides from the differences, if any, they had with the inactive peptides in that respect. The system made 100% correct prediction for the training set peptides and misclassified only one inactive peptide of the test set. The system also identified crucial residues for lambda repressor 12-24 and insulin A-chains. This identification also shows that activity related/crucial residues could be located at varying distances from the peptide terminals. To our knowledge, the method is unique of its kind in the literature and may find application in the rational design of synthetic vaccines and other peptides of immunological importance.

Alleles↗
PubMedDate not supplied

Intraoperative transesophageal echocardiography: correlation of echocardiographic findings and surgical pathology.

Before the introduction of transesophageal echocardiography (TEE) in the operating room, intraoperative echocardiography relied on epicardial imaging. The disadvantages of this approach included interference with the surgical procedure, limited windows, and potential distortion of cardiac structures. Consequently, multiplane TEE has now emerged as the intraoperative imaging method of choice. It provides high-resolution images of cardiac structures and excellent portraits of flow abnormalities. Intraoperative TEE does not interfere with the surgical field and procedure. TEE provides better imaging of the valves, atria, aorta, pulmonic vasculature, and pericardium, which are sometimes difficult to visualize by transthoracic echocardiography. TEE is especially beneficial in surgeries for valve replacement, valve repair, cardiac mass, aortic disease, congenital heart disease, and pericardial disease. Presurgical TEE provides information for surgical planning. TEE is helpful for the assessment of the immediate result of surgery and detection of complications that may need a prompt response. Thus, intraoperative TEE has a vital impact on management of cardiac surgery.

Echocardiography, Transesophageal↗
PubMedDate not supplied

In vitro evaluation of five alternative methods of carious dentine excavation.

This in-vitro, split-tooth study aimed to evaluate the efficiency (time taken) and effectiveness (quantity of dentine removed) of four techniques of carious dentine excavation (bur, air-abrasion, sono-abrasion and Carisolv gel) compared to conventional hand excavation. Eighty freshly extracted human molars were assigned to four experimental groups (n = 20), sectioned longitudinally through occlusal lesions and pre-excavation colour photomicrographs obtained. Using the natural autofluorescence of carious dentine (detected using confocal laser scanning microscopy) as an objective and reproducible guide, carious dentine removal was assessed in each half of the split tooth sample, comparing hand excavation to the test method. The time taken to reach a cavity floor that was hard to a dental probe was noted and final colour photomicrographs were taken. From the results, it was concluded that bur excavation was quickest but overprepared cavities relative to the autofluorescent signature, whereas Carisolv excavation was slowest but removed adequate quantities of tissue. Sono-abrasion tended to underprepare whereas air-abrasion was more comparable to hand excavation in both the time and amounts of dentine removed. Conventional hand excavation appeared to offer the best combination of efficiency and effectiveness for carious dentine excavation within the parameters used in this study.

Air Abrasion, Dental↗
PubMedDate not supplied

Relationships between a clinical-visual scoring system and two histological techniques: a laboratory study on occlusal and approximal carious lesions.

One aim of the present laboratory study was to determine whether a visual scoring system (ERK) developed for occlusal caries could be applied to approximal lesions. A new histological technique (autofluorescence, AF) recognises dentine that is soft and would be removed with an excavator during operative treatment. A second aim was to investigate the relationship between the visual scoring system (ERK) and AF of dentine both occlusally and approximally. The sample comprised 93 extracted teeth chosen to represent the range of visual scores on approximal and occlusal surfaces. After sectioning through the investigation site, the cut faces were examined in a stereomicroscope and the depth of demineralization was scored. Autofluorescence was viewed with a confocal laser scanning microscope. Results showed reasonable correlation between the visual scores and the stereomicroscope histological evaluations for occlusal surfaces and non-cavitated approximal surfaces. However, cavitated approximal surface lesions were less advanced histologically than cavitated occlusal carious lesions. The AF technique indicated that several lesions with intact surfaces would have had soft, excavatable dentine, whereas several with microcavities would not.

Dental Caries↗
PubMedDate not supplied

Clinical trial of an air-abrasion/chemomechanical operative procedure for the restorative treatment of dental patients.

The aim of this study was to investigate whether caries removal with air-abrasion/Carisolv gel is an acceptable and viable alternative in the treatment of dental patients. Twenty-two patients were treated with conventional methods (local anaesthetic injection/drill) followed by alternative treatment (air-abrasion and Carisolv gel) in a general practice setting, by the same operator. The participants' pre-operative anxiety levels were measured using the Modified Dental Anxiety Scale. Their postoperative levels of anxiety/dislike for aspects of both conventional and alternative treatments were assessed using a visual analogue scale. Levels of anxiety/dislike for both treatments were compared and statistically analysed. Results showed 100% of subjects were concerned about several aspects of conventional treatment including pain/discomfort on injection, taste of anaesthetic, length of time tissues remained numb, noise of the drill, its sensory vibrations and water coolant. However, 75% of the study population were happy with all aspects of the air-abrasion technique including dust, pain/discomfort and vibrations produced. Overall, the study population found Carisolv gel to be an acceptable alternative method of caries removal in terms of time taken, pain/discomfort and taste. There were statistically significant differences between patients' perceptions of various aspects of the two treatment methods. All participants found the alternative treatment to be pain-free, quicker and overall more acceptable compared with conventional treatment. The conclusion drawn from the study was that air-abrasion/Carisolv gel treatment was a well-accepted and viable alternative to conventional local anaesthetic injection and drill for dental patients.

Adolescent↗
PubMedDate not supplied

Dentine caries: take it or leave it?

In modern dentistry the primary aim when excavating carious dentine is to eradicate only the highly infected, irreversibly demineralized and denatured biomass in order to allow effective restoration of the cavity, restoration of the surface anatomy of the tooth and to prevent disease progression. However, the boundary between this superficial zone of dentine requiring excavation and the deeper, affected but repairable tissue is not always obvious either in the clinic or in the research laboratory. The inherent subjectivity in detecting this excavation boundary can result in clinically significant differences in the quality and quantity of dentine removed by different operators and makes the in vitro comparison of newer excavation techniques more difficult. This article discusses the rationale behind carious dentine excavation and the criteria available to the dentist, both clinical and laboratory, to help identify the dentine requiring removal.

Bacteria↗
PubMedDate not supplied

Semen characteristics of tobacco users in India.

Qualitative analysis of semen samples have been compared between 79 different types of tobacco addicts (smokers, chewers, and multiple addicts) with 21 nonaddicts (never consumed any form of tobacco). The percentage of motile sperm and total sperm count of the tobacco chewers are significantly low (p < .05). The frequency of abnormal sperm is also significantly high (p < .001) for smoking and multiple addict groups. Differential effects of smoking and chewing tobacco on sperm characteristics are discussed.

Adult↗
PubMedDate not supplied

Control of tachycardia and hypertension following coronary artery bypass graft surgery: efficacy and haemodynamic effects of esmolol.

Hypertension following coronary artery bypass grafting is not uncommon, especially in patients having good left ventricular function. It is often accompanied by tachycardia. The purpose of this study is to determine the efficacy of esmolol in the treatment of tachycardia and hypertension immediately following cardiopulmonary bypass and to study other haemodynamic effects of esmolol. Thirty patients undergoing elective [corrected] coronary artery bypass grafting were included in this prospective study. Morphine-based anaesthetic technique along-with standard bypass techniques were used in all the patients. The study was performed in the operating room about 30-45 minutes after the termination of cardiopulmonary bypass. Patients having a heart rate of more than 90 bpm and systolic blood pressure of more than 130 mm Hg without any inotropic support were included and randomly assigned to esmolol or control group. Esmolol was administered in a bolus dose of 500 micrograms/kg followed by infusion of upto 100 micrograms/kg/min. The patients in the control group were administered comparable volumes of normal saline. Baseline haemodynamic measurements were obtained just before the administration of esmolol or normal saline and were repeated after 5, 10, 15, 30 and 45 min. The baseline measurement in both the groups showed that patients were maintaining a state of hyperdynamic circulation with high systolic blood pressure (esmolol group 148 +/- 15 mm Hg, control group 140 +/- 8 mm Hg; p = NS), heart rate (esmolol group 128 +/- 17 bpm, control group 127 +/- 17 bpm; p = NS) and cardiac index (esmolol group 3.1 +/- 1 L/min/m2, control group 3.3 +/- 0.5 L/min/m2; p = NS). Esmolol decreased systolic blood pressure (p < 0.001), heart rate (p < 0.01) and cardiac index (p < 0.05) at five minutes. These changes persisted throughout the study period. The left ventricular stroke work index decreased at five minutes (p < 0.05) and remained so till 30 minutes. The maximum fall in heart rate (15%) and systolic blood pressure (16%) was observed at 45 minutes. There were no haemodynamic changes in the control group except that cardiac index, stroke volume and left ventricular stroke work index increased at five minutes. We conclude that esmolol lowers the indices of cardiovascular work in patients who demonstrated hyperdynamic circulation. This was achieved by decreasing the heart rate and systolic blood pressure which was accompanied by decrease in cardiac index and left ventricular stroke work index.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Importance of venting the left ventricle in aortic valve surgery.

Routine use of left ventricular vent is controversial in patients undergoing open heart surgery. However, surgeons use it during valvular surgery to maintain a dry field to make the operation easier. In addition it helps to prevent left ventricular distention during the critical period of rewarming and reperfusion, if ventricular function does not return immediately following the release of aortic cross clamp. In our country, patients present for valvular surgery at a very late stage and they often have severe left ventricular hypertrophy. This may affect the return of cardiac rhythm after the release of aortic cross clamp with progressive left ventricular distention. In the authors' experience, insertion of left ventricular vent through the apex is occasionally necessary to decompress the left ventricle as the left atrial vent usually fails to do so. This paper deals with retrospective analysis of the seven patients (out of a total of 395 patients who underwent valve surgery) who required insertion of left ventricular vent through the apex and reviews the beneficial effects of an apical left ventricular vent under refractory circumstances. It is recommended that insertion of left ventricular vent through apex should be strongly considered in patients having severe aortic valve disease with hypertrophied hearts, if cardiac rhythm in not restored with conventional management with left atrial vent and 3 to 5 DC shocks following the release of aortic cross clamp.

Adult↗
PubMedDate not supplied

Intrapericardial teratoma masquerading as pyopericardium.

A 10-year-old boy was admitted with cardiac tamponade. Initial pericardiocentasis yielded pus. A subxiphoid tube-pericardiostomy was done and thick, purulent material was drained out. Subsequently, pericardiectomy was undertaken as features of pericardial constriction persisted. At surgery, however, an intrapericardial mass was discovered. Successful excision was performed and the patient made an uneventful recovery. Histopathology of the mass revealed features of an intrapericardial teratoma. Rarity of the lesion, and a hitherto unreported mode of presentation make this case worthy of documentation.

Cardiac Tamponade↗
PubMedDate not supplied

Immortalization of fibroblasts from two patients with hereditary retinoblastoma.

Two RB fibroblastic strains from patients with hereditary retinoblastoma (RB), namely, RB80F/250R and RB110F, were transfected with plasmid DNAs encoding SV-40 large T-antigen at passage 31 and 10, respectively, These transfected fibroblasts developed into two immortalized cell lines. RB80F/250R/ori- and RB110F/gpt. RB110F/gpt had a similar doubling time as the parental cells, whereas RB80F/250R/ori- grew more rapidly with a doubling time of 19 hours compared to the parental cells which had a doubling time of 50 hours. The RB80F/250R/ori- cell line was particularly interesting cytogenetically since no normal chromosome 13 was present, although a marker chromosome 13 was found. In contrast, two apparently normal chromosome 13s were present in RB110F/gpt cells, but these cells had a marker chromosome which involved chromosome 14 (14 p+). Both the cell lines also had an abnormal chromosome 1 (1q-). RFLP analysis using the chromosome 13 specific VNTR probe, pTH162, assigned to 13q14.1 showed that the DNA from the RB80F/250R/ori- cells contained only a 6.1kb allelic fragment whereas the DNAs from parental RB80F/250R and RB80F cultures demonstrated both the polymorphic 8.0kb and 6.1kb allelic fragments. However, the RB gene per se was normal at the DNA level. Both cell lines expressed SV-40 large T-antigen together with elevated levels of p53 protein. In addition, levels of RB protein were the same in exponentially growing nontransformed parental cell strains and their immortalized cell lines. However, at confluency the levels of RB protein were greatly reduced in nontransformed cells but not in immortalized cell lines under similar conditions. In future studies using these immortalized cell lines, we shall make an attempt to discern the role of the RB gene and other tumor suppressor genes in the regulation of normal and malignant growth.

Cell Division↗