403 research outputs found
A comparison of free-standing versus co-located long-term acute care hospitals
Background Long-term acute care hospitals (LTACs) provide specialized treatment for patients with chronic critical illness. Increasingly LTACs are co-located within traditional short-stay hospitals rather than operated as free-standing facilities, which may affect LTAC utilization patterns and outcomes. Methods We compared free-standing and co-located LTACs using 2005 data from the United States Centers for Medicare & Medicaid Services. We used bivariate analyses to examine patient characteristics and timing of LTAC transfer, and used propensity matching and multivariable regression to examine mortality, readmissions, and costs after transfer. Results Of 379 LTACs in our sample, 192 (50.7%) were free-standing and 187 (49.3%) were co-located in a short-stay hospital. Co-located LTACs were smaller (median bed size: 34 vs. 66, p <0.001) and more likely to be for-profit (72.2% v. 68.8%, p = 0.001) than freestanding LTACs. Co-located LTACs admitted patients later in their hospital course (average time prior to transfer: 15.5 days vs. 14.0 days) and were more likely to admit patients for ventilator weaning (15.9% vs. 12.4%). In the multivariate propensity-matched analysis, patients in co-located LTACs experienced higher 180-day mortality (adjusted relative risk: 1.05, 95% CI: 1.00-1.11, p = 0.04) but lower readmission rates (adjusted relative risk: 0.86, 95% CI: 0.75-0.98, p = 0.02). Costs were similar between the two hospital types (mean difference in costs within 180 days of transfer: -8,720 -$1,550, p = 0.17). Conclusions Compared to patients in free-standing LTACs, patients in co-located LTACs experience slightly higher mortality but lower readmission rates, with no change in overall resource use as measured by 180 day costs
Fast spin echo sequences for BOLD functional MRI
At higher field strengths, spin echo (SE) functional MRI (fMRI) is an attractive alternative to gradient echo (GE) as the increased weighting towards the microvasculature results in intrinsically better localization of the BOLD signal. Images are free of signal voids but the commonly used echo planar imaging (EPI) sampling scheme causes geometric distortions, and T2* effects often contribute considerably to the signal changes measured upon brain activation. Multiply refocused SE sequences such as fast spin echo (FSE) are essentially artifact free but their application to fast fMRI is usually hindered due to high energy deposition, and long sampling times. In the work presented here, a combination of parallel imaging and partial Fourier acquisition is used to shorten FSE acquisition times to near those of conventional SE-EPI, permitting sampling of eight slices (matrix 64Ā Ā ĆĀ Ā 64) per second. Signal acquisition is preceded by a preparation experiment that aims at increasing the relative contribution of extravascular dynamic averaging to the BOLD signal. Comparisons are made with conventional SE-EPI using a visual stimulation paradigm. While the observed signal changes are approximately 30% lower, most likely due to the absence of T2* contamination, activation size and t-scores are comparable for both methods, suggesting that HASTE fMRI is a viable alternative, particularly if distortion free images are required. Our data also indicate that the BOLD post-stimulus undershoot is most probably attributable to persistent elevated oxygen metabolism rather than to delayed vascular compliance
Stem cell-based therapy for human diseases.
Recent advancements in stem cell technology open a new door for patients suffering from diseases and disorders that have yet to be treated. Stem cell-based therapy, including human pluripotent stem cells (hPSCs) and multipotent mesenchymal stem cells (MSCs), has recently emerged as a key player in regenerative medicine. hPSCs are defined as self-renewable cell types conferring the ability to differentiate into various cellular phenotypes of the human body, including three germ layers. MSCs are multipotent progenitor cells possessing self-renewal ability (limited in vitro) and differentiation potential into mesenchymal lineages, according to the International Society for Cell and Gene Therapy (ISCT). This review provides an update on recent clinical applications using either hPSCs or MSCs derived from bone marrow (BM), adipose tissue (AT), or the umbilical cord (UC) for the treatment of human diseases, including neurological disorders, pulmonary dysfunctions, metabolic/endocrine-related diseases, reproductive disorders, skin burns, and cardiovascular conditions. Moreover, we discuss our own clinical trial experiences on targeted therapies using MSCs in a clinical setting, and we propose and discuss the MSC tissue origin concept and how MSC origin may contribute to the role of MSCs in downstream applications, with the ultimate objective of facilitating translational research in regenerative medicine into clinical applications. The mechanisms discussed here support the proposed hypothesis that BM-MSCs are potentially good candidates for brain and spinal cord injury treatment, AT-MSCs are potentially good candidates for reproductive disorder treatment and skin regeneration, and UC-MSCs are potentially good candidates for pulmonary disease and acute respiratory distress syndrome treatment
Inter-Cellular Variation in DNA Content of Entamoeba histolytica Originates from Temporal and Spatial Uncoupling of Cytokinesis from the Nuclear Cycle
Accumulation of multiple copies of the genome in a single nucleus and several nuclei in a single cell has previously been noted in Entamoeba histolytica, contributing to the genetic heterogeneity of this unicellular eukaryote. In this study, we demonstrate that this genetic heterogeneity is an inherent feature of the cell cycle of this organism. Chromosome segregation occurs on a variety of novel microtubular assemblies including multi-polar spindles. Cytokinesis in E. histolytica is completed by the mechanical severing of a thin cytoplasmic bridge, either independently or with the help of neighboring cells. Importantly, cytokinesis is uncoupled from the nuclear division cycle, both temporally and spatially, leading to the formation of unequal daughter cells. Sorting of euploid and polyploid cells showed that each of these sub-populations acquired heterogeneous DNA content upon further growth. Our study conclusively demonstrates that genetic heterogeneity originates from the unique mode of cell division events in this protist
In vitro anti-malarial interaction and gametocytocidal activity of cryptolepine
YesBackground: Discovery of novel gametocytocidal molecules is a major pharmacological strategy in the elimination
and eradication of malaria. The high patronage of the aqueous root extract of the popular West African anti-malarial
plant Cryptolepis sanguinolenta (Periplocaceae) in traditional and hospital settings in Ghana has directed this study
investigating the gametocytocidal activity of the plant and its major alkaloid, cryptolepine. This study also investigates
the anti-malarial interaction of cryptolepine with standard anti-malarials, as the search for new anti-malarial combinations
continues.
Methods: The resazurin-based assay was employed in evaluating the gametocytocidal properties of C. sanguinolenta
and cryptolepine against the late stage (IV/V) gametocytes of Plasmodium falciparum (NF54). A fixed ratio method
based on the SYBR Green I fluorescence-based assay was used to build isobolograms from a combination of cryptolepine
with four standard anti-malarial drugs in vitro using the chloroquine sensitive strain 3D7.
Results: Cryptolepis sanguinolenta (
IC50 = 49.65 nM) and its major alkaloid, cryptolepine (
IC50 = 1965 nM), showed
high inhibitory activity against the late stage gametocytes of P. falciparum (NF54). In the interaction assays in asexual
stage, cryptolepine showed an additive effect with both lumefantrine and chloroquine with mean Ī£FIC50s of
1.017 Ā± 0.06 and 1.465 Ā± 0.17, respectively. Cryptolepine combination with amodiaquine at therapeutically relevant
concentration ratios showed a synergistic effect (mean Ī£FIC50 = 0.287 Ā± 0.10) whereas an antagonistic activity (mean
Ī£FIC50 = 4.182 Ā± 0.99) was seen with mefloquine.
Conclusions: The findings of this study shed light on the high gametocytocidal properties of C. sanguinolenta and
cryptolepine attributing their potent anti-malarial activity mainly to their effect on both the sexual and asexual stages
of the parasite. Amodiaquine is a potential drug partner for cryptolepine in the development of novel fixed dose
combinations
Nationwide shifts in the double burden of overweight and underweight in Vietnamese adults in 2000 and 2005: two national nutrition surveys
<p>Abstract</p> <p>Background</p> <p>In developing countries, overweight prevalence is increasing while underweight prevalence is still high. This situation is known as the double nutrition burden. Both underweight and overweight are related to increased risk of chronic non-communicable diseases, reduced well-being and quality of life. This study aims to compare the prevalence of overweight and underweight among Vietnamese adults in 2000 and 2005.</p> <p>Methods</p> <p>The study was based on two nationally representative surveys, the National Nutrition Survey 2000 (14,452 subjects) and the National Adult Obesity Survey 2005 (17,213 subjects). Adults aged 25-64 years were sampled to be nationally representative. Multiple multinomial logistic regression analysis was used to investigate the association of underweight and overweight with socio-economic indicators.</p> <p>Results</p> <p>The distribution of BMI across the population and population groups indicated a shift towards higher BMI levels in 2005 as compared to 2000. The nationwide prevalence of overweight (BMI ā„ 25 kg/m<sup>2</sup>) and obesity (BMI ā„ 30 kg/m<sup>2</sup>) was 6.6% and 0.4% respectively in 2005, almost twice the rates of 2000 (3.5% and 0.2%). Using the Asian BMI cut-off of 23 kg/m<sup>2 </sup>the overweight prevalence was 16.3% in 2005 and 11.7% in 2000. In contrast, the underweight prevalence (BMI < 18.5 kg/m<sup>2</sup>) of 20.9% in 2005 was lower than the rate of 25.0% in 2000. Women were more likely to be both underweight and overweight as compared to men in both 2000 and 2005. Urban residents were more likely to be overweight and less likely to be underweight as compared to rural residents in both years. The shifts from underweight to overweight were clearer among the higher food expenditure levels.</p> <p>Conclusions</p> <p>The double nutrition burden was clearly present in Vietnam. The distribution of BMI across the population groups generally indicated a shift towards higher BMI levels in 2005 as compared to 2000. The prevalence of overweight was increased while the declined level of undernutrition was still high in 2005. The shifts of underweight to overweight were most obvious among population groups with higher food expenditure levels.</p
Modulation of calcification of vascular smooth muscle cells in culture by calcium antagonists, statins, and their combination
Background Vascular calcification is an organized process in which vascular smooth muscle cells (VSMCs) are implicated primarily. The purpose of the present study was to assess the effects of calcium antagonists and statins on VSMC calcification inĀ vitro. Methods VSMC calcification was stimulated by incubation in growth medium supplemented with 10Ā mmol/l Ī²-glycerophosphate, 8Ā mmol/l CaCl2, 10Ā mmol/l sodium pyruvate, 1Ā Ī¼mol/l insulin, 50Ā Ī¼g/ml ascorbic acid, and 100Ā nmol/l dexamethasone (calcification medium). Calcification, proliferation, and apoptosis of VSMCs were quantified. Results Calcium deposition was stimulated dose-dependently by Ī²-glycerophosphate, CaCl2, and ascorbic acid (all PĀ <Ā 0.01). Addition of amlodipine (0.01ā1Ā Ī¼mol/l) to the calcification medium did not affect VSMC calcification. However, atorvastatin (2ā50Ā Ī¼mol/l) stimulated calcium deposition dose-dependently. Combining treatments stimulated calcification to a degree similar to that observed with atorvastatin alone. Both atorvastatin and amlodipine inhibited VSMC proliferation at the highest concentration used. Only atorvastatin (50Ā Ī¼mol/l) induced considerable apoptosis of VSMCs. Conclusion InĀ vitro calcification of VSMCs is not affected by amlodipine, but is stimulated by atorvastatin at concentrations ā„10Ā Ī¼mol/l, which could contribute to the plaque-stabilizing effect reported for statins
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