Investigation of shock compression of composite porous media by a nondisturbing electromagnetic technique

A remote-control electromagnetic technique is developed to determine the mass velocity behind a shock wave(SW) in porous, fibrous, and other heterogeneous media. As an application of the technique a shock adiabat ofAl ₂O₃ powder of bulk density was constructed in the region of low pressures.Translated from Fizika Goreniya i Vzryva, Vol. 32, No. 2, pp. 124–129, March–April, 1996.     

Detection of Salmonella typhi in the blood of patients with typhoid fever by polymerase chain reaction

A polymerase chain reaction (PCR)-based test was developed for the detection of Salmonella typhi in the blood specimens from patients with typhoid fever. Two pairs of oligonucleotide primers were designed to amplify a 343-bp fragment of the flagellin gene of S. typhi. Amplified products were analyzed by agarose gel electrophoresis and Southern blot hybridization by using a 32P-labeled 40-base probe internal to the amplified DNA. The nested PCR with two pairs of primers could detect 10 organisms of S. typhi as determined by serial dilutions of DNA from S. typhi. The peripheral mononuclear cells from 11 of 12 patients with typhoid fever confirmed by blood culture were positive for DNA fragment of the flagellin gene of S. typhi, whereas 10 blood specimens of patients with other febrile diseases were negative. With the nested PCR, S. typhi DNAs were detected from blood specimens of four patients with suspected typhoid fever on the basis of clinical features but with negative cultures. We suggest that the PCR technique could be used as a novel diagnostic method of typhoid fever, particularly in culture-negative cases.     

Strategic hospital alliances: impact on financial performance

Acute care hospitals have increasingly been forming local strategic hospital alliances (SHAs), which consume considerable resources in forming and may affect the competitiveness of provider markets. This research shows that SHAs and market factors, which have been perceived to be threats to hospitals, are related to hospitals' financial performance. Among the findings are that SHA members have higher net revenues but that they are not more effective at cost control. Nor do the higher net revenues result in higher cash flow. However, increasing SHA penetration in a market is related to lower net revenues per case. In addition, the penetration of private health maintenance organizations in markets is associated with lower revenues and expenses.     

Correspondence of left ventricular ejection fraction determinations from two-dimensional echocardiography, radionuclide angiography and contrast cineangiography

OBJECTIVES: This study assessed the agreement of left ventricular ejection fraction determinations from two-dimensional echocardiography, radionuclide angiography and contrast cineangiography. BACKGROUND: Previously published reports suggest that two-dimensional echocardiography, radionuclide angiography and contrast cineangiography are equally acceptable methods of assessing left ventricular ejection fraction on the basis of high coefficients of correlation. However, correlation of methods does not necessarily imply agreement. METHODS: In a prospective analysis, 25 consecutive subjects all had two-dimensional echocardiography and radionuclide angiography performed within 10 days of each other in the cardiology department of metropolitan community hospital. A retrospective computer search (Medline) revealed seven studies, using the coefficient of correlation (r), comparing two-dimensional echocardiographic left ventricular ejection fraction (n = 268) with radionuclide angiographic (n = 174) or contrast cineangiographic (n = 119) left ventricular ejection fractions. RESULTS: The eight individual studies (n = 293) comparing two-dimensional echocardiography with either radionuclide angiography or contrast cineangiography exhibited coefficients of correlation ranging from 0.78 to 0.93. Agreement analysis using the method of Bland and Altman was performed by averaging the results obtained from the two techniques and determining how disparate any single ejection fraction was (with 95% confidence limits) from the mean value. Agreement ranged from 23% to 42% around the mean ejection fraction. The average lack of agreement between the two methods for all studies involved was 17%, with an average r value of 0.86. CONCLUSIONS: Left ventricular ejection fraction determinations by means of two-dimensional echocardiography, radionuclide angiography and contrast cineangiography exhibit high correlation and only moderate agreement. High correlation does not always imply high agreement. These results suggest that, when validated by agreement analysis, multiple studies may not be necessary in appropriate clinical situations, potentially reducing costs.     

Fracture behaviour of pressure die-cast aluminium-graphite composites

Fracture toughness values of pressure die-cast Al-7Si-3 Mg-5 graphite composites were measured and found to be in the range 8–10 MPa m^1/2. Detailed microstructure of the composite and the fractured surfaces were examined. Defects such as clusters, agglomerations and segregation of graphite particles, play a dominant role in accelerating the fracture process. In addition, the acicular silicon phase present in the matrix and the casting defects, such as gas and shrinkage porosities, also initiated and accelerated the crack, thus lowering the fracture toughness of the composites.     

Volume-rendered three-dimensional dynamic anatomy of the mitral annulus using a transesophageal echocardiographic technique

Mitral annulus anatomy and dynamics were evaluated in 12 subjects using a three-dimensional transesophageal echocardiographic technique. The mitral annular area, diameters and distance from the left ventricular apex were measured in end-diastole, mid-systole, end-systole and mid-diastole. The mitral annulus had its largest area in end-systole and the smallest area in end-diastole. The shape of the annulus changed during the cardiac cycle with the maximal change occurring in the diameters passing close to the middle of the mitral leaflets. In the vertical plane, the annulus had a shallow ski-slope shape, with the attachment of the anterior leaflet being farthest from the apex. In other words, the highest point of the annulus was situated anteromedially and was visualized in the long axis imaging plane.     

Immunotoxins containing Pseudomonas exotoxin that target LeY damage human endothelial cells in an antibody-specific mode: relevance to vascular leak syndrome

Vascular leak syndrome (VLS) was originally found to be a major dose-limiting toxicity in humans with cancer treated with several immunotoxins (ITs) containing ricin A chain or blocked ricin. Recently, VLS has also been observed in patients treated with an IT containing the murine monoclonal antibody (MAb) B3 coupled to LysPE38, a recombinant truncated form of Pseudomonas exotoxin (PE) A. Antibody B3 (IgG1k) recognizes LewisY and related carbohydrate epitopes present on many human solid tumors, and B3-LysPE38 showed excellent antitumor activity in nude mice bearing tumors that express the B3 antigen. In the clinical trial, the development of VLS has prevented the administration of the amount of IT necessary to achieve blood levels required for good therapeutic responses. We have now investigated the effects of several PE-based ITs on different human endothelial cell lines to elucidate the mechanism of VLS induced by ITs containing PE. To assess the cytotoxic effect of IT on endothelial cells, various ITs were incubated with cells for 2 or 20 h, and the incorporation of [3H]leucine into protein was measured. The endothelial cells studied were human umbilical vein endothelial cells, human lung-derived microvascular endothelial cells (HUVECs), human adult dermal microvascular endothelial cells, human pulmonary artery endothelial cells, and human aortic endothelial cells. We found that both B3-LysPE38 (LMB-1), a chemical conjugate of MAb B3 with PE38, as well as B3(Fv)-PE38 (LMB-7), a recombinant single chain immunotoxin, inhibited protein synthesis, with 50% inhibitory concentrations between 600 and 1000 ng/ml for 20-h incubation in HUVECs, human lung-derived microvascular endothelial cells, and human adult dermal microvascular endothelial cells but not on human pulmonary artery endothelial cells. The cytotoxic effect was specific since PE38 itself or PE coupled to several other antibodies did not inhibit protein synthesis in these cells even at 10,000 ng/ml. Further evidence that the cytotoxicity of B3-containing ITs is due to specific B3 binding to endothelial cells comes from the fact that the cytotoxicity can be blocked by excess free MAb B3. HUVECs undergo overt morphological changes after treatment with B3-LysPE38 or B3(Fv)PE38. Gaps between the cells are formed after a 20-h exposure but not after 2 h. These studies suggest that VLS in patients is due to capillary damage caused by prolonged exposure to high concentrations of LMB-1.