Whole body MR imaging in ankylosing spondylitis: a descriptive pilot study in patients with suspected early and active confirmed ankylosing spondylitis

Background  

Ankylosing spondylitis is a chronic inflammatory rheumatic disorder which usually begins in early adulthood. The diagnosis is often delayed by many years. MR imaging has become the preferred imaging method for detection of early inflammation of the axial skeleton in ankylosing spondylitis.     

Comparison of PCR with the routine procedure for diagnosis of tuberculosis in a population with high prevalences of tuberculosis and human immunodeficiency virus

Direct smear examination with Ziehl-Neelsen (ZN) staining for the diagnosis of tuberculosis (TB) as employed in most low-income countries is cheap and easy to use, but its low sensitivity is a major drawback. The low specificity of chest X-rays, used for the diagnosis of smear-negative TB, risks high levels of overdiagnosis. Major advances in molecular techniques, which rapidly identify mycobacterial DNA in sputa, may overcome these obstacles. In this study, the AMPLICOR PCR system was used to diagnose pulmonary TB in a developing country with high prevalences of both TB and human immunodeficiency virus (HIV). The sensitivity and specificity of this technique were compared to those of the usual diagnostic techniques. Sputum specimens were collected from 1,396 TB suspects attending the Rhodes Chest Clinic, Nairobi, Kenya. The specimens were analyzed for the presence of Mycobacterium tuberculosis by PCR; culture on Löwenstein-Jensen medium was used as the “gold standard.” All culture-positive samples were genotyped to identify the mycobacterial species. The sensitivity and specificity of PCR were 93 and 84%, respectively. HIV status did not affect the sensitivity of PCR. A total of 99.7% of the true smear-positive and 82.1% of the true smear-negative TB patients were correctly identified by PCR. PCR detected M. tuberculosis in 11.7% of the culture-negative suspects, 60% of which had one or two PCR-positive sputum specimens. Of the 490 positive cultures, 486 were identified as M. tuberculosis. The high sensitivity of Amplicor PCR merits usage in a clinical setting with high TB and HIV burdens. Thus, PCR can be considered as an alternative to ZN staining in combination with chest X-ray for diagnosis of TB; however, cost-effectiveness studies and operational studies are required to support an evidence-based decision of introducing PCR for TB control in high-burden environments.Tuberculosis (TB) is one of the most serious infectious diseases and a considerable public health problem due to its high risk of person-to-person transmission, morbidity, and mortality. Both the human immunodeficiency virus (HIV) epidemic and social deterioration have contributed to the overall increase in the Mycobacterium tuberculosis infection rate, especially in developing countries, where resources are scarce (13). In Nairobi the case detection rate increased from 78 per 100,000 in 1991 to 581 per 100,000 in 2001, with a total number of 12,963 cases.Early diagnosis followed by adequate treatment is essential to prevent both morbidity and mortality. Although the conventional technique of direct smear examination with Ziehl-Neelsen staining (ZN) is cheap and easy to perform, its low sensitivity is a major drawback. Depending on the number of specimens examined, ZN detects 30 to 60% of the culture-positive “TB suspects” (7). Furthermore, it requires sputum samples collected on consecutive days, making the procedure slow and making patient compliance with the diagnostic process difficult.New techniques are very much needed (7), and molecular amplification assays such as PCR have been shown to be promising alternatives even for developing countries (2). PCR has the potential to be a cost-effective alternative, provided the diagnosis can be determined with one sputum examination (8). If diagnosis can be established faster, and the diagnostic process becomes less cumbersome for the patient, PCR may reduce delay both in diagnosis and in the start of treatment.Depending on the “gold standard” and other methodological factors, studies show PCR sensitivities ranging from 77% to more than 95% and PCR specificities of >95% for smear-positive specimens (4, 9, 10, 12). However, sensitivities for smear-negative TB patients have been reported to be below 90% (9). Most PCR studies have been performed in industrial countries (4, 9, 10, 12) where the TB and HIV burdens are low.To investigate the performance and feasibility of PCR in an environment of TB endemicity and high prevalences of HIV and AIDS, a study was conducted in Nairobi, Kenya, comparing PCR to conventional routine diagnostic methods within a program setup. In this study, the Roche Amplicor Mycobacteria PCR test for the direct detection of M. tuberculosis was used on sputum specimens from TB suspects attending a chest clinic in Nairobi. Its performance was compared with those of the basic routine diagnostic procedures according to the national guidelines (6), including clinical findings, ZN, and chest X-rays (CXR), on smear-negative suspects. Löwenstein-Jensen (LJ) culture results were used as the gold standard.     

慢性低氧时小鼠肺组织低氧诱导因子-1α的表达

目的：研究低氧时小鼠肺组织中低氧诱导因子-1α(HIF-k)表达的变化。方法：实验用雄性小鼠，低氧仓浓度分别为10％、7％、5％。用免疫荧光组织化学技术及共聚焦显微术，检测小鼠在低氧条件下肺组织中HIF-1α表达的变化。结果：正常组小鼠肺组织HIF-1α无表达，低氧组HIF-1α表达增加，且随低氧时间的延长及低氧强度的增加而增强。结论：低氧可诱导小鼠肺组织中HIF-1α的表达增强，(HIF-k)可能参与肺组织细胞凋亡的发生。     

Risk factors for pneumonia in urban-dwelling HIV-infected women: a case-control study in Nairobi,Kenya

In sub-Saharan Africa, respiratory tract infections (RTI) are the leading cause of serious morbidity and mortality in HIV-infected persons. This study sought to investigate demographic, socioeconomic, and environmental risk factors for pneumonia in a cohort of HIV-infected women. The authors performed a nested case-control study in a cohort of HIV-1-infected adults followed in Nairobi, Kenya. Thirty-nine women who developed pneumonia during the follow-up period were selected as cases, and 66 women who did not develop pneumonia were randomly chosen to serve as control subjects. A questionnaire was administered in subjects' homes that assessed demographics, home environment, and socioeconomic status. Women were followed in the cohort for a median of 36.8 months (range, 27.3-39.3). Adjusting for length of follow-up period, factors associated with lower socioeconomic status (lower monthly spending [OR = 3.2; 95% CI, 1.2-8.4 per 10,000 Kenyan shilling decrease], having no savings [OR = 4.1; 95% CI, 1.4-11.9], less sturdy home construction material such as mud or cement walls [OR = 2.6; 95% CI, 1.1-5.9] or dirt floors [OR = 2.8; 95% CI, 1.0-7.6], and lack of a window in the home [OR = 5.5; 95% CI, 0.9-32.2]) and being widowed (OR = 4.3; 95% CI, 1.2-15.1) or single (OR = 3.3; 95% CI, 1.0-11.2) were associated with an increased risk of pneumonia. In multivariate analysis, widowed (AOR = 5.9; 95% CI, 1.3-26.3), single (AOR = 7.7; 95% CI, 1.6-36.4), and divorced (AOR = 4.5; 95% CI, 1.0-20.1) women, those without savings (AOR = 3.7; 95% CI, 1.2-11.7), and those living in more crowded and contagious conditions (AOR = 1.5; 95% CI, 1.1-2.1) remained at increased risk of pneumonia. If confirmed by prospective investigation, these findings could help identify persons and subpopulations of HIV-infected women with the greatest risk of pneumonia.     

<Emphasis Type="Italic">TCF7L2</Emphasis>variant genotypes and type 2 diabetes risk in Brazil: significant association,but not a significant tool for risk stratification in the general population

Background  

Genetic polymorphisms of the TCF7L2 gene are strongly associated with large increments in type 2 diabetes risk in different populations worldwide. In this study, we aimed to confirm the effect of the TCF7L2 polymorphism rs7903146 on diabetes risk in a Brazilian population and to assess the use of this genetic marker in improving diabetes risk prediction in the general population.