Comparison of 2D versus M-mode echocardiography for assessing fetal myocardial wall thickness

Objective: M-mode and 2D have been proposed for evaluating fetal myocardial thickness. However, studies comparing the performance of both modalities are lacking. We aimed to compare 2D versus M-mode reproducibility for assessing myocardial wall thicknesses.

Methods: A prospective study including 45 healthy fetuses from low-risk pregnancies evaluated between 18 and 41 weeks of gestation. Left and right ventricular free-wall and septal myocardial thicknesses were measured at end-diastole (ED) and end-systole (ES) in transverse 4-chamber view using 2D and M-mode. Intra- and interobserver reproducibility was evaluated by the concordance correlation coefficient (CCC). Both techniques were compared by t-test of the CCC.

Results: 2D and M-mode demonstrated excellent and similar intraobserver repeatability, with the best concordance in ES septal thickness (M-mode CCC 0.956 versus 2D-mode CCC 0.914). Interobserver reproducibility demonstrated also a high concordance, optimal in ES left ventricular free wall (M-mode 0.925 versus 2 D 0.855). Comparison of both techniques demonstrated a high concordance in all measurements, except for ED septal thickness with better reproducibility using M-mode (CCC 0.954 versus 0.847, p?=?.017).

Conclusions: 2D and M-mode can be used in a reproducible manner for measuring fetal myocardial thickness, with a slightly better performance of M-mode for assessing ED septal wall thickness.     

Impact of selenium status on the pathogenesis of mycobacterial disease in HIV-1-infected drug users during the era of highly active antiretroviral therapy

The risk of mycobacterial disease is significantly increased in drug abusers as well as in immunocompromised HIV-1-infected individuals. The essential trace element selenium has an important function in maintaining immune processes and may, thus, have a critical role in clearance of mycobacteria. The impact of selenium status on the development of mycobacterial diseases in HIV-1-seropositive drug users was investigated over a 2-year period (1999-2001). Twelve cases of mycobacterial disease (tuberculosis, 9; infection due to atypical Mycobacterium species, 3) occurred; these 12 cases were compared with 32 controls with no history of respiratory infections who were matched on age, sex, and HIV status. Significant risk for development of mycobacterial disease was associated with a CD4 cell count of <200/mm 3, malnutrition, and selenium levels of 相似文献   

Performance of lipid fingerprint-based MALDI-ToF for the diagnosis of mycobacterial infections

ObjectivesBacterial diagnosis of mycobacteria is often challenging because of the variability of the sensitivity and specificity of the assay used, and it can be expensive to perform accurately. Although matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) has become the workhorse of clinical laboratories, the current MALDI methodology (which is based on cytosolic protein profiling) for mycobacteria is still challenging due to the number of steps involved (up to seven) and potential biosafety concerns. Knowing that mycobacteria produce surface-exposed species-specific lipids, we here hypothesized that the detection of those molecules could offer a rapid, reproducible and robust method for mycobacterial identification.MethodsWe evaluated the performance of an alternative methodology based on characterized species-specific lipid profiling of intact bacteria, without any sample preparation, by MALDI MS; it uses MALDI-time-of-flight (ToF) MS combined with a specific matrix (super-2,5-dihydroxybenzoic acid solubilized in an apolar solvent system) to analyse lipids of intact heat-inactivated mycobacteria. Cultured mycobacteria are heat-inactivated and loaded directly onto the MALDI target followed by addition of the matrix. Acquisition of the data is done in both positive and negative ion modes. Blinded studies were performed using 273 mycobacterial strains comprising both the Mycobacterium tuberculosis (Mtb) complex and non-tuberculous mycobacteria (NTMs) subcultured in Middlebrook 7H9 media supplemented with 10% OADC (oleic acid/dextrose/catalase) growth supplement and incubated for up to 2 weeks at 37°C.ResultsThe method we have developed is fast (<10 mins) and highly sensitive (<1000 bacteria required); 96.7% of the Mtb complex strains (204/211) were correctly assigned as MTB complex and 91.7% (22/24) NTM species were correctly assigned based only on intact bacteria species-specific lipid profiling by MALDI-ToF MS.ConclusionsIntact bacterial lipid profiling provides a biosafe and unique route for rapid and accurate mycobacterial identification.     

Heat stress risk profiles for three non-woven coveralls

The ACGIH® Threshold Limit Value® (TLV®) is used to limit heat stress exposures so that most workers can maintain thermal equilibrium. That is, the TLV was set to an upper limit of Sustainable exposures for most people. This article addresses the ability of the TLV to differentiate between Sustainable and Unsustainable heat exposures for four clothing ensembles over a range of environmental factors and metabolic rates (M). The four clothing ensembles (woven clothing, and particle barrier, water barrier and vapor barrier coveralls) represented a wide range of evaporative resistances. Two progressive heat stress studies provided data on 480 trials with 1440 pairs of Sustainable and Unsustainable exposures for the clothing over three levels of relative humidity (rh) (20, 50 and 70%), three levels of metabolic rate (115, 180, and 254 Wm^?2) using 29 participants. The exposure metric was the difference between the observed wet bulb globe temperature (WBGT) and the TLV. Risk was characterized by odds ratios (ORs), Receiver Operating Characteristic (ROC) curves, and dose-response curves for the four ensembles. Conditional logistic regression models provided information on ORs. Logistic regressions were used to determine ROC curves with area under the curve (AUC), model the dose-response curve, and estimate offsets from woven clothing. The ORs were about 2.5 per 1°C-WBGT for woven clothing, particle barrier, and water barrier and for vapor barrier at 50% rh. When using the published Clothing Adjustment Values (CAVs, also known as Clothing Adjustment Factors, CAFs) or the offsets that included different values for vapor barrier based on rh, the AUC for all clothing was 0.86. When the fixed CAVs of the TLV were used, the AUC was 0.81. In conclusion, (1) ORs and the shapes of the dose-response curves for the nonwoven coveralls were similar to woven clothing, and (2) CAVs provided a robust way to account for the risk of nonwoven clothing. The robust nature of CAV extended to the exclusion of different adjustments for vapor barrier by rh.     

Influence of Protrusive Functions on Electromyographic Activity of Elevator Muscles

Several authors have studied the influence of varied centric and eccentric occlusal relationships on neuromusculature. However, the authors know of no research comparing the effects on mandibular muscle activity of different occlusal functions in protrusive guidance.

This study used an orthopedic splint to compare the influence exerted by different protrusive occlusal functions on elevator muscle activity. The paper also explains the neuromusculature involved and quantifies the activity in comparison with registration in the mandibular centric position.     

Ultrasound as a Diagnostic Aid in Identifying Neurofibromas

Neurofibromatosis 1 is a multisystem disorder associated with substantial clinical variability. During childhood, few neurofibromas and café au lait spots may be the only manifest symptoms, making correct and timely diagnosis difficult. Herein we describe the clinical usefulness of ultrasound examination in identifying neurofibromas.     

Characterization of fibrillar collagen isoforms in infarcted mouse hearts using second harmonic generation imaging

We utilized collagen specific second harmonic generation (SHG) signatures coupled with correlative immunofluorescence imaging techniques to characterize collagen structural isoforms (type I and type III) in a murine model of myocardial infarction (MI). Tissue samples were imaged over a four week period using SHG, transmitted light microscopy and immunofluorescence imaging using fluorescently-labeled collagen antibodies. The post-mortem cardiac tissue imaging using SHG demonstrated a progressive increase in collagen deposition in the left ventricle (LV) post-MI. We were able to monitor structural morphology and LV remodeling parameters in terms of extent of LV dilation, stiffness and fiber dimensions in the infarcted myocardium.