11 research outputs found
A study of the remarkable galaxy system AM 546-324 (the core of Abell S0546)
We report first results of an investigation of the tidally disturbed galaxy
system AM\,546-324, whose two principal galaxies 2MFGC 04711 and AM\,0546-324
(NED02) were previously classified as interacting doubles. This system was
selected to study the interaction of ellipticals in a moderately dense
environment. We provide spectral characteristics of the system and present an
observational study of the interaction effects on the morphology, kinematics,
and stellar population of these galaxies. The study is based on long-slit
spectrophotometric data in the range of 4500-8000 obtained with
the Gemini Multi-Object Spetrograph at Gemini South (GMOS-S). We have used the
stellar population synthesis code STARLIGHT to investigate the star formation
history of these galaxies. The Gemini/GMOS-S direct r-G0303 broad band pointing
image was used to enhance and study fine morphological structures. The main
absorption lines in the spectra were used to determine the radial velocity.
Along the whole long-slit signal, the spectra of the Shadowy galaxy (discovered
by us), 2MFGC 04711, and AM\,0546-324 (NED02) resemble that of an early-type
galaxy. We estimated redshifts of z= 0.0696, z= 0.0693 and z= 0.0718,
corresponding to heliocentric velocities of 20\,141 km s, 20\,057 km
s, and 20\,754 km s for the Shadowy galaxy, 2MFGC 04711 and
AM\,0546-324 (NED02), respectively. ..
Xpert MTB/RIF and Xpert Ultra assays for screening for pulmonary tuberculosis and rifampicin resistance in adults, irrespective of signs or symptoms
Background
Tuberculosis is a leading cause of infectious diseaseârelated death and is one of the top 10 causes of death worldwide. The World Health Organization (WHO) recommends the use of specific rapid molecular tests, including Xpert MTB/RIF or Xpert Ultra, as initial diagnostic tests for the detection of tuberculosis and rifampicin resistance in people with signs and symptoms of tuberculosis. However, the WHO estimates that nearly oneâthird of all active tuberculosis cases go undiagnosed and unreported. We were interested in whether a single test, Xpert MTB/RIF or Xpert Ultra, could be useful as a screening test to close this diagnostic gap and improve tuberculosis case detection.
Objectives
To estimate the accuracy of Xpert MTB/RIF and Xpert Ultra for screening for pulmonary tuberculosis in adults, irrespective of signs or symptoms of pulmonary tuberculosis in highârisk groups and in the general population. Screening "irrespective of signs or symptoms" refers to screening of people who have not been assessed for the presence of tuberculosis symptoms (e.g. cough).
To estimate the accuracy of Xpert MTB/RIF and Xpert Ultra for detecting rifampicin resistance in adults screened for tuberculosis, irrespective of signs and symptoms of pulmonary tuberculosis in highârisk groups and in the general population.
Search methods
We searched 12 databases including the Cochrane Infectious Diseases Group Specialized Register, MEDLINE and Embase, on 19 March 2020 without language restrictions. We also reviewed reference lists of included articles and related Cochrane Reviews, and contacted researchers in the field to identify additional studies.
Selection criteria
Crossâsectional and cohort studies in which adults (15 years and older) in highârisk groups (e.g. people living with HIV, household contacts of people with tuberculosis) or in the general population were screened for pulmonary tuberculosis using Xpert MTB/RIF or Xpert Ultra. For tuberculosis detection, the reference standard was culture. For rifampicin resistance detection, the reference standards were cultureâbased drug susceptibility testing and line probe assays.
Data collection and analysis
Two review authors independently extracted data using a standardized form and assessed risk of bias and applicability using QUADASâ2. We used a bivariate randomâeffects model to estimate pooled sensitivity and specificity with 95% credible intervals (CrIs) separately for tuberculosis detection and rifampicin resistance detection. We estimated all models using a Bayesian approach. For tuberculosis detection, we first estimated screening accuracy in distinct highârisk groups, including people living with HIV, household contacts, people residing in prisons, and miners, and then in several highârisk groups combined.
Main results
We included a total of 21 studies: 18 studies (13,114 participants) evaluated Xpert MTB/RIF as a screening test for pulmonary tuberculosis and one study (571 participants) evaluated both Xpert MTB/RIF and Xpert Ultra. Three studies (159 participants) evaluated Xpert MTB/RIF for rifampicin resistance. Fifteen studies (75%) were conducted in high tuberculosis burden and 16 (80%) in high TB/HIVâburden countries. We judged most studies to have low risk of bias in all four QUADASâ2 domains and low concern for applicability.
Xpert MTB/RIF and Xpert Ultra as screening tests for pulmonary tuberculosis
In people living with HIV (12 studies), Xpert MTB/RIF pooled sensitivity and specificity (95% CrI) were 61.8% (53.6 to 69.9) (602 participants; moderateâcertainty evidence) and 98.8% (98.0 to 99.4) (4173 participants; highâcertainty evidence). Of 1000 people where 50 have tuberculosis on culture, 40 would be Xpert MTB/RIFâpositive; of these, 9 (22%) would not have tuberculosis (falseâpositives); and 960 would be Xpert MTB/RIFânegative; of these, 19 (2%) would have tuberculosis (falseânegatives).
In people living with HIV (1 study), Xpert Ultra sensitivity and specificity (95% CI) were 69% (57 to 80) (68 participants; very lowâcertainty evidence) and 98% (97 to 99) (503 participants; moderateâcertainty evidence). Of 1000 people where 50 have tuberculosis on culture, 53 would be Xpert Ultraâpositive; of these, 19 (36%) would not have tuberculosis (falseâpositives); and 947 would be Xpert Ultraânegative; of these, 16 (2%) would have tuberculosis (falseânegatives).
In nonâhospitalized people in highârisk groups (5 studies), Xpert MTB/RIF pooled sensitivity and specificity were 69.4% (47.7 to 86.2) (337 participants, lowâcertainty evidence) and 98.8% (97.2 to 99.5) (8619 participants, moderateâcertainty evidence). Of 1000 people where 10 have tuberculosis on culture, 19 would be Xpert MTB/RIFâpositive; of these, 12 (63%) would not have tuberculosis (falseâpositives); and 981 would be Xpert MTB/RIFânegative; of these, 3 (0%) would have tuberculosis (falseânegatives).
We did not identify any studies using Xpert MTB/RIF or Xpert Ultra for screening in the general population.
Xpert MTB/RIF as a screening test for rifampicin resistance
Xpert MTB/RIF sensitivity was 81% and 100% (2 studies, 20 participants; very lowâcertainty evidence), and specificity was 94% to 100%, (3 studies, 139 participants; moderateâcertainty evidence).
Authors' conclusions
Of the highârisks groups evaluated, Xpert MTB/RIF applied as a screening test was accurate for tuberculosis in high tuberculosis burden settings. Sensitivity and specificity were similar in people living with HIV and nonâhospitalized people in highârisk groups. In people living with HIV, Xpert Ultra sensitivity was slightly higher than that of Xpert MTB/RIF and specificity similar. As there was only one study of Xpert Ultra in this analysis, results should be interpreted with caution. There were no studies that evaluated the tests in people with diabetes mellitus and other groups considered at highârisk for tuberculosis, or in the general population
Body mass index is superior to other body adiposity indexes in predicting incident hypertension in a highly admixed sample after 10âyear followâup: The Baependi Heart Study
Abstract Hypertension is the leading cause of overall mortality in lowâ and middleâincome countries. In Brazil, there is paucity of data on the determinants of incident hypertension and related risk factors. We aimed to determine the incidence of hypertension in a sample from the Brazilian population and investigate possible relationships with body adiposity indexes. We assessed risk factors associated with cardiovascular disease, including adiposity body indexes and biochemical analysis, in a sample from the Baependi Heart Study before and after a 10âyear followâup. Hypertension was defined by the presence of systolic blood pressure (SBP) â„140 mmHg and/or diastolic blood pressure â„90 mmHg or the use of antihypertensive drugs. From an initial sample of 1693 participants, 498 (56% women; mean age 38 ± 13 years) were eligible to be included. The overall hypertension incidence was 24.3% (22.3% in men and 25.6% in women). Persons who developed hypertension had higher prevalence of obesity, higher levels for blood pressure, higher frequency of dyslipidemia, and higher body adiposity indexes at baseline. The best prediction model for incident hypertension includes age, sex, HDLâc, SBP, and Body Mass Index (BMI) [AUC = 0.823, OR = 1.58 (95% CI 1.23â2.04)]. BMI was superior in its predictive capacity when compared to Body Adiposity Index (BAI), Body Roundness Index (BRI), and Visceral Adiposity Index (VAI). Incident hypertension in a sample from the Brazilian population was 24.3% after 10âyear followâup and BMI, albeit the simpler index to be calculated, is the best anthropometric index to predict incident hypertension