An in vitro study on human ureteric smooth muscle with the alpha1-adrenoceptor subtype blocker, tamsulosin

OBJECTIVE

To study the effects of tamsulosin on ureteric contractions and its effects on the basal tone of human ureteric specimens, as clinical trials with tamsulosin have shown promising results in the spontaneous expulsion of lower ureteric calculus, but the mechanism of action of tamsulosin in the expulsion of ureteric calculus has not been elucidated in in‐vitro studies on human ureters.

MATERIALS AND METHODS

Human mid‐ureteric specimens were obtained from live kidney donors. The specimen was transported in Krebs’ solution and the isometric contraction of human ureteric smooth muscle was recorded in the presence of tamsulosin. Ureteric rings from 19 kidney donors were studied.

RESULTS

At 100 µm tamsulosin the frequency of ureteric contraction was blocked completely, or the contraction frequency was reduced in 89% of specimens. There was no change in the frequency or in the amplitude of contraction in the remaining specimens. The basal tone of the ureter was reduced in 16% of the specimens.

CONCLUSION

Our results suggest that peristaltic activity in human ureteric smooth muscle is inhibited by tamsulosin. The effect of tamsulosin on basal tone is marginal.     

Postlaryngectomy hypertensive crisis: a manifestation of perioperative acute baroreflex failure?

Hemodynamic instability as a result of altered baroreflex mechanism is common in surgeries involving manipulation around the carotid sheath. We report a case in which hypertensive crisis was associated with laryngectomy during general anesthesia. Perioperative use of vasoactive agents such as alpha(2) agonists may help in maintaining hemodynamic stability in such procedures.     

Relationship between p53 overexpression, human papillomavirus infection, and lifestyle in Indian patients with head and neck cancers

Exposure to pollutants in the environment, tobacco and alcohol consumption, poor oral hygiene and opportunistic viral infections are important aetiological factors in head and neck cancers. In this study, we evaluate the complex interrelationships between these factors and molecular events such as p53 overexpression in causation of head and neck cancers. Tissue samples from 110 patients with histopathologically confirmed carcinoma of head and neck were analyzed from our tissue biorepository with patient consent. Data pertaining to their dietary habits, tobacco and alcohol consumption were abstracted. P53 overexpression was analysed by immunohistochemistry and HPV (high-risk genotype) were studied by Chromogenic in situ Hybridization using an ultra sensitive DNA probe. Chi-square analysis was done to determine relationships between proportions of dependent and independent variables. Bivariate relationships were determined between these variables using Spearman's rank correlation. Linear regression analysis was used to determine the best predictor variable influencing p53 expression. Tobacco consumption especially smoking cigarettes and all forms of tobacco consumption put together and HPV infection significantly influenced p53 overexpression. Forty-five percent of the studied cohort was positive for HPV. Regression analysis showed interaction between tobacco and HPV infection to be a primary predictor (β = 0.31, p = 0.02) for p53 expression. Tobacco in any form: chewing, smoking and snuffing, along with HPV infection is significantly associated with p53 overexpression. There is a high prevalence of HPV infection (45%) in Indian patients suggesting its possible role in the aetiology of head and neck cancer.     

Characterization of responses and comparison of calibration factor for commercial MOSFET detectors

A commercial metal oxide silicon field effect transistor (MOSFET) dosimeter of model TN502-RD has been characterized for its linearity, reproducibility, field size dependency, dose rate dependency, and angular dependency for Cobalt-60 (⁶⁰Co), 6-MV, and 15-MV beam energies. The performance of the MOSFET clearly shows that it is highly reproducible, independent of field size and dose rate. Furthermore, MOSFET has a very high degree of linearity, with r-value > 0.9 for all 3 energies. The calibration factor for 2 similar MOSFET detectors of model TN502-RD were also estimated and compared for all 3 energies. The calibration factor between the 2 similar MOSFET detectors shows a variation of about 1.8% for ⁶⁰Co and 15 MV, and for 6 MV it shows variation of about 2.5%, indicating that calibration should be done whenever a new MOSFET is used. However, the detector shows considerable angular dependency of about 8.8% variation. This may be due to the variation in radiation sensitivity between flat and bubble sides of the MOSFET, and indicates that positional care must be taken while using MOSFET for stereotactic radiosurgery and stereotactic radiotherapy dosimetric applications.     

A baseline survey of the prevalence of tuberculosis in a community in south India at the commencement of a DOTS programme.

OBJECTIVE: To determine the baseline prevalence of culture-positive and smear-positive tuberculosis and the annual risk of tuberculous infection (ARTI) in a community in south India where DOTS is being implemented. METHODS: Using cluster sampling, 50 rural panchayats (villages) and three urban units in Tiruvallur district were selected randomly. All adults aged > or = 15 years underwent symptom and radiographic examination, and those with abnormal shadows and/or chest symptoms had sputum smear and culture examination. In another cluster sample of 73 villages and three urban units, all children aged < 10 years were tuberculin tested. RESULTS: The prevalence of culture-positive and smear-positive tuberculosis was respectively 605 and 323/100,000. Both increased appreciably with age, and were substantially higher in males than in females at all ages; the overall male:female ratio was 5.5 for culture-positive and 6.5 for smear-positive tuberculosis. The ARTI in children aged under 10 years was 1.6%, and was unaffected by sex. Over three decades there was an overall decline of 1.8% per annum in the prevalence of culture-positive and 2.1% for smear-positive tuberculosis. CONCLUSION: Tuberculosis is a major problem in this rural community in south India, with a prevalence of 605/100,000 for culture-positive tuberculosis and 323/100,000 for smear-positive tuberculosis.     

肺结核相关生物学与行为学危险因素的研究

目的：用现患优势比（POR）来评估与肺结核有关的独立危险因素，包括年龄、性别、吸烟、嗜酒等。方法：自2001年6月-2003年12月进行了社区横断面调查。在南印度的一个区随机抽取的村庄中，共调查年龄≥15岁的村民93945人，用胸部症状和胸部X光片（MMR）作为筛查肺结核的指征。具有上述2项指征之一的病人均留取痰标本2份（1份现场留取，1份次日清晨留取）：1份用于痰涂片镜检抗酸杆菌，1份用于结核分枝杆菌培养。痰涂片或培养阳性的病例被判定为菌阳病例。此外，只在男性人群中收集吸烟和饮酒史资料，所有女性均认为无吸烟、饮酒史。结果：调查期间共诊断了429例菌阳病例。年龄、性别、吸烟和嗜酒的校正PORs（用95％可信区间）分别为3．3（2．7—4．1）、2．5（1．9—3．3）、2．1（1．7—2．7）和1．5（1．2—2．0）。结论：年龄、性别、吸烟和嗜酒等危险因素与肺结核独立相关，年龄、性别因素较吸烟、嗜酒相关性更强。     

Additional risk of developing TB for household members with a TB case at home at intake: a 15-year study.

OBJECTIVE: To assess the additional risk to household contacts from an infectious case of tuberculosis (TB) at home in a rural community in south India. METHODS: In all, 3506 contacts of smear-positive (S+C+) and 2910 contacts of smear-negative TB cases (S-C+) and 246 845 persons with no TB case at home were followed for 15 years, with a repeat survey every 2.5 years consisting of radiographic and sputum examination, selective follow-up of high-risk individuals and passive surveillance. If a case developed during follow-up, all household members were subsequently considered as contacts. Cox's proportional hazards model (multivariate) was employed to compare incidences. RESULTS: The annual incidence of culture-positive TB was respectively 526 and 271 per 100000 population for contacts of smear-positive and smear-negative patients, and 198/100000 in non-contacts. The adjusted hazard rate was 3.4 for contacts of smear-positive patients (95% CI 3.0-3.9) and 1.7 for contacts of smear-negative patients (95% CI 1.4-2.0) as compared to non-contacts. Of 3942 incident cases, 337 (8.5%) came from households with a TB case. CONCLUSION: Although family contacts had a significantly higher incidence, their contribution to total new caseload was meagre. Contact chemoprophylaxis as a public health measure would therefore have limited impact on community TB incidence.     

Light trapping and power conversion efficiency of P3HT : nano Si hybrid solar cells

In this study, the hybrid solar cells (HSCs) were fabricated with high-purity nano Si from nano SiO₂ precursor extracted from natural minerals, that is, quartz sand. The prepared nano Si was used as an electron transport material to prepare an active layer material mixture with poly(3-hexylthiophene) (P3HT) by mixing it in two composition ratios, namely 1 : 1 and 1 : 0.8. The blended active layer solutions (ALSs) were prepared by using solvents such as 1,2-dichlorobenzene (DCB), chlorobenzene (CB), and chloroform (CF). The HSCs were fabricated using six blended ALSs, namely ALS1, ALS2, ALS3, ALS4, ALS5, and ALS6. The current density–voltage characteristics of the fabricated HSCs were studied using a simulated AM 1.5G illumination having light density power of 100 mW cm⁻². The characterization properties such as short circuit current density (J_sc) and power conversion efficiency (PCE) were studied and compared with those of all six HSCs fabricated with six blended ALSs. At the outset, the P3HT : nano-Si (1 : 0.8) blended ALS in CB solvent shows 2.37% PCE, and 46% of external quantum efficiency (EQE) absorption which is higher than the other fabricated solar cells. This study discusses the possibilities of preparation of nano Si from natural mineral sand, as an effective electron transport material to fabricate HSCs with enhanced PCE.

In this study, the hybrid solar cells (HSCs) were fabricated with high-purity nano Si from nano SiO₂ precursor extracted from natural minerals, that is, quartz sand.