57 research outputs found
Development of a respiratory severity score for hospitalized adults in a high HIV-prevalence settingβSouth Africa, 2010-2011
BACKGROUND : Acute lower respiratory tract infections (LRTI) are a frequent cause of hospitalization and mortality in
South Africa; however, existing respiratory severity scores may underestimate mortality risk in HIV-infected adults in
resource limited settings. A simple predictive clinical score for low-resource settings could aid healthcare providers
in the management of patients hospitalized with LRTI.
METHODS : We analyzed 1,356 LRTI hospitalizations in adults aged β₯18 years enrolled in Severe Acute Respiratory
Illness (SARI) surveillance in three South African hospitals from January 2010 to December 2011. Using demographic
and clinical data at admission, we evaluated potential risk factors for in-hospital mortality. We evaluated three
existing respiratory severity scores, CURB-65, CRB-65, and Classification Tree Analysis (CTA) Score assessing for
discrimination and calibration. We then developed a new respiratory severity score using a multivariable logistic
regression model for in-hospital mortality and assigned points to risk factors based on the coefficients in the
multivariable model. Finally we evaluated the model statistically using bootstrap resampling techniques.
RESULTS : Of the 1,356 patients hospitalized with LRTI, 101 (7.4%) died while hospitalized. The CURB-65, CRB-65, and
CTA scores had poor calibration and demonstrated low discrimination with c-statistics of 0.594, 0.548, and 0.569
respectively. Significant risk factors for in-hospital mortality included age β₯ 45 years (A), confusion on admission (C),
HIV-infection (H), and serum blood urea nitrogen >7 mmol/L (U), which were used to create the seven-point ACHU
clinical predictor score. In-hospital mortality, stratified by ACHU score was: score β€1, 2.4%, score 2, 6.4%, score 3, 11.
9%, and score β₯ 4, 29.3%. Final models showed good discrimination (c-statistic 0.789) and calibration (chi-square 1.6,
Hosmer-Lemeshow goodness-of-fit p-value = 0.904) and discriminated well in the bootstrap sample (average
optimism of 0.003).
CONCLUSIONS : Existing clinical predictive scores underestimated mortality in a low resource setting with a high HIV
burden. The ACHU score incorporates a simple set a risk factors that can accurately stratify patients β₯18 years of
age with LRTI by in-hospital mortality risk. This score can quantify in-hospital mortality risk in an HIV-endemic,
resource-limited setting with limited clinical information and if used to facilitate timely treatment may improve
clinical outcomes.Additional file 1: BMC Pulmonary_Severity Score Data.xlsx. Severity
Score Dataset. Dataset generated and used for analysis and creation of
the ACHU score. Two tabs are included 1) includes the data used for the
analysis 2) includes important notes related to the analytical methods
and definitions for several composite variables.Additional file 2: Table S1. CURB-65, CRB-65, Classification Tree
Analysis (CTA) severity scores. Table S2. Predicted and observed risk of
mortality based on CURB-65, CRB-65, Classification Tree Analysis (CTA),
and CURB-45 severity scores among hospitalized adults with lower
respiratory tract infections, South Africa, 2010β2011. Table S3. Predicted
and observed risk of mortality based by ACHU (Age, confusion, HIV, urea)
respiratory severity score among hospitalized adults with lower
respiratory tract infections, South Africa, 2010β2011.The Centers for Disease Control and Preventionhttp://www.biomedcentral.com/bmccom/plementalternmedam2017Medical Virolog
Opportunities for mesoscopics in thermometry and refrigeration: Physics and applications
This review presents an overview of the thermal properties of mesoscopic
structures. The discussion is based on the concept of electron energy
distribution, and, in particular, on controlling and probing it. The
temperature of an electron gas is determined by this distribution:
refrigeration is equivalent to narrowing it, and thermometry is probing its
convolution with a function characterizing the measuring device. Temperature
exists, strictly speaking, only in quasiequilibrium in which the distribution
follows the Fermi-Dirac form. Interesting nonequilibrium deviations can occur
due to slow relaxation rates of the electrons, e.g., among themselves or with
lattice phonons. Observation and applications of nonequilibrium phenomena are
also discussed. The focus in this paper is at low temperatures, primarily below
4 K, where physical phenomena on mesoscopic scales and hybrid combinations of
various types of materials, e.g., superconductors, normal metals, insulators,
and doped semiconductors, open up a rich variety of device concepts. This
review starts with an introduction to theoretical concepts and experimental
results on thermal properties of mesoscopic structures. Then thermometry and
refrigeration are examined with an emphasis on experiments. An immediate
application of solid-state refrigeration and thermometry is in ultrasensitive
radiation detection, which is discussed in depth. This review concludes with a
summary of pertinent fabrication methods of presented devices.Comment: Close to the version published in RMP; 59 pages, 35 figure
Failure of adaptive self-organized criticality during epileptic seizure attacks
Critical dynamics are assumed to be an attractive mode for normal brain
functioning as information processing and computational capabilities are found
to be optimized there. Recent experimental observations of neuronal activity
patterns following power-law distributions, a hallmark of systems at a critical
state, have led to the hypothesis that human brain dynamics could be poised at
a phase transition between ordered and disordered activity. A so far unresolved
question concerns the medical significance of critical brain activity and how
it relates to pathological conditions. Using data from invasive
electroencephalogram recordings from humans we show that during epileptic
seizure attacks neuronal activity patterns deviate from the normally observed
power-law distribution characterizing critical dynamics. The comparison of
these observations to results from a computational model exhibiting
self-organized criticality (SOC) based on adaptive networks allows further
insights into the underlying dynamics. Together these results suggest that
brain dynamics deviates from criticality during seizures caused by the failure
of adaptive SOC.Comment: 7 pages, 5 figure
Trends of the Major Porin Gene (ompF) Evolution: Insight from the Genus Yersinia
OmpF is one of the major general porins of Enterobacteriaceae that belongs to the first line of bacterial defense and interactions with the biotic as well as abiotic environments. Porins are surface exposed and their structures strongly reflect the history of multiple interactions with the environmental challenges. Unfortunately, little is known on diversity of porin genes of Enterobacteriaceae and the genus Yersinia especially. We analyzed the sequences of the ompF gene from 73 Yersinia strains covering 14 known species. The phylogenetic analysis placed most of the Yersinia strains in the same line assigned by 16S rDNA-gyrB tree. Very high congruence in the tree topologies was observed for Y. enterocolitica, Y. kristensenii, Y. ruckeri, indicating that intragenic recombination in these species had no effect on the ompF gene. A significant level of intra- and interspecies recombination was found for Y. aleksiciae, Y. intermedia and Y. mollaretii. Our analysis shows that the ompF gene of Yersinia has evolved with nonrandom mutational rate under purifying selection. However, several surface loops in the OmpF porin contain positively selected sites, which very likely reflect adaptive diversification Yersinia to their ecological niches. To our knowledge, this is a first investigation of diversity of the porin gene covering the whole genus of the family Enterobacteriaceae. This study demonstrates that recombination and positive selection both contribute to evolution of ompF, but the relative contribution of these evolutionary forces are different among Yersinia species
New Approaches in the Differentiation of Human Embryonic Stem Cells and Induced Pluripotent Stem Cells toward Hepatocytes
Orthotropic liver transplantation is the only established treatment for end-stage liver diseases. Utilization of hepatocyte transplantation and bio-artificial liver devices as alternative therapeutic approaches requires an unlimited source of hepatocytes. Stem cells, especially embryonic stem cells, possessing the ability to produce functional hepatocytes for clinical applications and drug development, may provide the answer to this problem. New discoveries in the mechanisms of liver development and the emergence of induced pluripotent stem cells in 2006 have provided novel insights into hepatocyte differentiation and the use of stem cells for therapeutic applications. This review is aimed towards providing scientists and physicians with the latest advancements in this rapidly progressing field
Impact of GeneXpert MTB/RIF Assay on Triage of Respiratory Isolation Rooms for Inpatients With Presumed Tuberculosis: A Hypothetical Trial
BackgroundPlacing inpatients with presumed active pulmonary tuberculosis in respiratory isolation pending results of serial sputum acid-fast bacilli (AFB) smear microscopy is standard practice in high-income countries. However, this diagnostic strategy is slow and yields few tuberculosis diagnoses. We sought to determine if replacing microscopy with the GeneXpert MTB/RIF (Xpert) nucleic acid amplification assay could reduce testing time and usage of isolation rooms.MethodsWe prospectively followed inpatients at San Francisco General Hospital undergoing tuberculosis evaluation. We performed smear microscopy and Xpert testing on concentrated sputum, and calculated diagnostic accuracy for both strategies in reference to serial sputum mycobacterial culture. We measured turnaround time for microscopy and estimated hypothetical turnaround times for Xpert on concentrated and unconcentrated sputum. We compared median and total isolation times for microscopy to those estimated for the 2 Xpert strategies.ResultsAmong 139 patients with 142 admissions, median age was 54 years (interquartile range [IQR], 43-60 years); 32 (23%) patients were female, and 42 (30%) were HIV seropositive. Serial sputum smear microscopy and a single concentrated sputum Xpert had identical sensitivity (89%; 95% confidence interval [CI], 52%-100%) and similar specificity (99% [95% CI, 96%-100%] vs 100% [95% CI, 97%-100%]). A single concentrated sputum Xpert could have saved a median of 35 hours (IQR, 24-36 hours) in unnecessary isolation compared with microscopy, and a single unconcentrated sputum Xpert, 45 hours (IQR, 35-46 hours).ConclusionsReplacing serial sputum smear microscopy with a single sputum Xpert could eliminate most unnecessary isolation for inpatients with presumed tuberculosis, greatly benefiting patients and hospitals
Review of the status and challenges associated with increasing influenza vaccination coverage among pregnant women in China
Influenza vaccination coverage in pregnant women in China remains low. In this review, we first provide an overview of the evidence for the use of influenza vaccination during pregnancy. Second, we discuss influenza vaccination policy and barriers to increased seasonal influenza vaccination coverage in pregnant women in China. Third, we provide case studies of successes and challenges of programs for increasing seasonal influenza vaccination in pregnant women from other parts of Asia with lessons learned for China. Finally, we assess opportunities and challenges for increasing influenza vaccination coverage among pregnant women in China
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Rapid Molecular Testing for TB to Guide Respiratory Isolation in the U.S.: A Cost-Benefit Analysis
Influenza Outbreaks among Passengers and Crew on Two Cruise Ships: a Recent Account of Preparedness and Response to an Ever-Present Challenge
Impact of GeneXpert MTB/RIF Assay on Triage of Respiratory Isolation Rooms for Inpatients With Presumed Tuberculosis: A Hypothetical Trial
Background.βPlacing inpatients with presumed active pulmonary tuberculosis in respiratory isolation pending results of serial sputum acid-fast bacilli (AFB) smear microscopy is standard practice in high-income countries. However, this diagnostic strategy is slow and yields few tuberculosis diagnoses. We sought to determine if replacing microscopy with the GeneXpert MTB/RIF (Xpert) nucleic acid amplification assay could reduce testing time and usage of isolation rooms. Methods.βWe prospectively followed inpatients at San Francisco General Hospital undergoing tuberculosis evaluation. We performed smear microscopy and Xpert testing on concentrated sputum, and calculated diagnostic accuracy for both strategies in reference to serial sputum mycobacterial culture. We measured turnaround time for microscopy and estimated hypothetical turnaround times for Xpert on concentrated and unconcentrated sputum. We compared median and total isolation times for microscopy to those estimated for the 2 Xpert strategies. Results.βAmong 139 patients with 142 admissions, median age was 54 years (interquartile range [IQR], 43β60 years); 32 (23%) patients were female, and 42 (30%) were HIV seropositive. Serial sputum smear microscopy and a single concentrated sputum Xpert had identical sensitivity (89%; 95% confidence interval [CI], 52%β100%) and similar specificity (99% [95% CI, 96%β100%] vs 100% [95% CI, 97%β100%]). A single concentrated sputum Xpert could have saved a median of 35 hours (IQR, 24β36 hours) in unnecessary isolation compared with microscopy, and a single unconcentrated sputum Xpert, 45 hours (IQR, 35β46 hours). Conclusions.βReplacing serial sputum smear microscopy with a single sputum Xpert could eliminate most unnecessary isolation for inpatients with presumed tuberculosis, greatly benefiting patients and hospitals
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