Nucleotide sequence of barley stripe mosaic virus RNAα: RNAα encodes a single polypeptide with homology to corresponding proteins from other viruses

The complete nucleotide sequence of RNAα from the Type strain of barley stripe mosaic virus has been determined. The RNA is 3768 nucleotides long and contains a single open reading frame which codes for a polypeptide of 1139 amino acids (mw 129,634). The open reading frame is flanked by a 5′-terminal sequence of 91 nucleotides and a 3′-nontranslated region composed of a short poly(A) tract followed by a 238-nucleotide tRNA-like structure. The amino acid sequence of the polypeptide (αa) encoded by the open reading frame has homology with the TMV 126K protein and with related polypeptides from other viruses. The carboxy-terminal portion of the as polypeptide also has limited homology with the 58K (βb) protein encoded by BSMV RNAβ and includes a consensus sequence found in mononucleotide-binding polypeptides.     

Comparative evaluation of two commercial assays for direct detection ofMycobacterium tuberculosis in respiratory specimens

Two commercial systems for the amplification and detection ofMycobacterium tuberculosis directly from respiratory samples were compared. The Roche Cobas Amplicor MTB Test and the Roche manual Amplicor MTB Test (Roche Diagnostic Systems, USA) were applied to 755 decontaminated respiratory specimens collected from 470 patients. Results were compared with those of acid-fast staining and culture. A total of 251 specimens were collected from 156 patients diagnosed with pulmonary tuberculosis, including 28 specimens corresponding to 13 patients that were receiving antituberculous treatment. Given the overall positivity rate of 33.2% (251/755), the sensitivity, specificity, and positive and negative predictive values were 92.4, 100, 100, and 96.5%, respectively, for the Cobas Amplicor MTB Test and 90.8, 100, 100, and 95.8%, respectively, for the Amplicor MTB Test. For 204 (81.3%) smear positive specimens and 47 (19.7%) smear negative specimens, the sensitivity values were 100 and 59.6%, respectively, for the Cobas Amplicor MTB Test and 100 and 51%, respectively, for the Amplicor MTB Test. There were no statistically significant differences in sensitivity or specificity between the two assays and culture (p>0.05). The overall results of both assays were concordant for 99.5% of the samples. It is concluded that although both nucleic acid amplification methods are rapid and specific for the detection ofMycobacterium tuberculosis complex in respiratory specimens, the Cobas Amplicor MTB Test appears to be slightly more sensitive than the Amplicor MTB Test when smear negative specimens are investigated.     

Heat-shock protein (HSP70-2) allelic frequencies in three distinct Mexican populations

The major histocompatibility complex (MHC) genes are highly polymorphic and therefore have been useful in population genetics and disease association studies. We analyzed restriction fragment length polymorphism of HSP70-2 alleles in healthy unrelated Mestizo, Mazatecan and Nahua populations. Both Indian groups, Mazatecans and Nahuas, were in Hardy-Weinberg equilibrium, while Mestizos were in disequilibrium (chi 2 = 0.399; P < 0.05). The Mazatecan Indians presented a high frequency of BB homozygosity (17.35%) compared to Mestizos (5%) (P = 0.01). Mexican ethnic groups present differences in distribution of BB genotype. The low frequency of BB genotype in Mestizos may be the result of a negative selection process.     

Neurological manifestations in chronic mountain sickness: the burning feet-burning hands syndrome

OBJECTIVE: To characterise the clinical features and nerve biopsy findings in patients with chronic mountain sickness (CMS) living in the Peruvian Andes, with particular attention to the occurrence of the "burning feet-burning hands" syndrome. METHODS: Symptoms and signs were documented clinically in 10 patients with CMS and compared with those in five healthy subjects all living at 4338 metres altitude. Sural nerve biopsies were obtained from three patients with CMS.The nerve fibre population and endoneurial microvessels were analyzed morphometrically. RESULTS: All patients with CMS experienced burning and tingling paraesthesiae in the distal parts of their limbs. Similar but milder symptoms confined to the feet occurred in four of five controls. Three patients with CMS had a mild sensory neuropathy on examination, controls were clinically normal. Nerve biopsies showed a mild demyelinating neuropathy in all three with a reduction in the unmyelinated axon population in one. The endoneurial blood vessels showed a reduced thickness in the basal laminal zone compared with control values but were otherwise normal. CONCLUSIONS: Apart from well recognised symptoms and signs of CMS, the study has shown that such patients may also exhibit a mild sensory neuropathy. Its relation to the burning feet-burning hands syndrome, which was not confined to the patients but was also found in controls at altitude, is uncertain. The time course and pattern of the centrifugal resolution of the burning paraesthesiae complex on low altitude sojourn of high altitude natives raises the possibility that a mechanism involving altered axonal transport may be involved. The reduced thickness of the basal laminal zone of microvessels implies that adaptive structural changes to hypobaric hypoxia may also occur in peripheral nerve and are similar to those reported in other tissues of high altitude natives.     

Hematological parameters in high altitude residents living at 4,355, 4,660, and 5,500 meters above sea level

There have been a number of reports describing the hematological indicators of Andean residents living at altitudes above 4,000 m, but several confounding factors have made the published results difficult to interpret. To clear up the effect of hypoxia on hemoglobin concentration (Hb, g/dL), hematocrit (Hct, %) and red blood cell concentration (RBC, cells/microL), this publication describes and analyzes these variables in children, men, and women from three large and homogeneous populations living at 4,355 m (n = 151), 4,660 m (n = 400), and 5,500 m (n = 273) in the Southern Peruvian Andes. Hb, Hct, and RBC increase with age in men (p < 0.001), as well as in women (p < 0.001) at the three altitudes of the study. In children (boys and girls) living at 5,500, Hb increases 11% when compared with children living at 4,355 m, and in adults, Hb increases 9.6% when comparing the same altitudes. The maximum percentage increase in Hb with age was 5.6% at 5,500 m, in men and 3.2% at 4,355 m, in women. The average percentage of difference for the Hb concentration between adult men and women is 6.6% at 4,355 m, 9.8% at 4,660 m, and 11.6% at 5,500 m. The differences in Hb concentration between men and women can only be seen after puberty. Finally, Hb is higher in older than younger women, which confirms the role of menopause in the development of erythremia. The result of this analysis reinforces the notion that Hb and Hct seem to be stable and useful parameters for acclimatization only at moderate altitudes; with aging or with increasing altitude, they may become excessive and lose their efficiency to protect the venous oxygen pressure.     

Comparison of an interferon-gamma assay with tuberculin skin testing for detection of tuberculosis (TB) infection in patients with rheumatoid arthritis in a TB-endemic population

OBJECTIVE: Tuberculosis (TB) in patients with rheumatoid arthritis (RA) undergoing treatment with anti-tumor necrosis factor (TNF) agents is commonly the result of reactivation of latent TB infection (LTBI); detection and treatment of LTBI is essential before treatment with anti-TNF agents. We reported previously that the tuberculin skin test (TST) is inaccurate for diagnosis of LTBI in patients with RA. Here, we compare the prevalence of LTBI in RA patients and matched controls according to positive TST and QuantiFeron-TB Gold In-Tube version (QFT) results and determine their agreement. METHODS: A cross-sectional study of 101 RA patients and 93 controls was conducted in Lima, Perú, where the prevalence of LTBI in the general population has been estimated to be 68%. Blood was drawn for QFT assay followed by TST using 2-TU of RT 23 purified protein derivative. TST was deemed positive at >or= 5 mm for RA patients and >or= 10 mm for controls. RESULTS: There were no significant differences between RA patients and controls for age, sex, bacillus Calmette-Guérin vaccination, or history of or contact with TB. 88% of patients had active RA disease and 2 (1.9%) patients had indeterminate QFT results. The number of subjects testing positive with the QuantiFeron assay was comparable between patients and controls (44.6% vs 59.1%, respectively), whereas the TST detected significantly less LTBI among RA patients (26.7%) than controls (65.6%). Thus, the rate of LTBI in RA patients represented 75% and 41% of the rate in their controls using QFT or TST, respectively (p = 0.008). Poor agreement between TST and QFT was seen in RA patients, but in controls, good agreement was observed between these tests. CONCLUSION: In a TB-endemic population, the QuantiFeron-TB Gold In-Tube assay seemed to be a more accurate test for detection of LTBI in RA patients compared with the TST, and may potentially improve the targeting of prophylactic therapy before treatment with anti-TNF agents.     

Urban HEART Detroit: a Tool To Better Understand and Address Health Equity Gaps in the City

The Urban Health Equity Assessment Response Tool (Urban HEART) combines statistical evidence and community knowledge to address urban health inequities. This paper describes the process of adopting and implementing this tool for Detroit, Michigan, the first city in the USA to use it. The six steps of Urban HEART were implemented by the Healthy Environments Partnership, a community-based participatory research partnership made up of community-based organizations, health service providers, and researchers based in academic institutions. Local indicators and benchmarks were identified and criteria established to prioritize a response plan. We examine how principles of CBPR influenced this process, including the development of a collaborative and equitable process that offered learning opportunities and capacity building among all partners. For the health equity matrix, 15 indicators were chosen within the Urban HEART five policy domains: physical environment and infrastructure, social and human development, economics, governance, and population health. Partners defined the criteria and ranked them for use in assessing and prioritizing health equity gaps. Subsequently, partners generated a series of potential actions for indicators prioritized in this process. Engagement of community partners contributed to benchmark selection and modification, and provided opportunities for dialog and co-learning throughout the process. Application of a CBPR approach provided a foundation for engagement of partners in the Urban HEART process of identifying health equity gaps. This approach offered multiple opportunities for discussion that shaped interpretation and development of strategies to address identified issues to achieve health equity.