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41.
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JP Edwards SJ West CL Pooley KB Marschke LJ Farmer TK Jones 《Canadian Metallurgical Quarterly》1998,8(7):745-750
Typhoid fever is often associated with abnormal liver biochemical tests, but severe hepatic involvement with a clinical feature of acute hepatitis is a rare complication. There have been more than 150 cases of salmonella hepatitis reported from both developed and developing countries. The documented incidence varies widely from less than 1% to 26% patients with enteric fever. The possible associated factors for development of salmonella hepatitis are virulence of the organisms, delayed treatment and poor general health of the patients. The pathogenesis of severe hepatic involvement in salmonella infection may be multifactorial and includes endotoxin, local inflammatory and/or host immune reactions. Clinical jaundice in salmonella hepatitis usually occurs within the first 2 weeks of the febrile illness. Hepatomegaly and moderate elevation of transaminase levels are common findings. Extreme hepatic dysfunction with hepatic encephalopathy is a rare coexisting complication in salmonella hepatitis. A positive culture for salmonella from blood or stool is essential to differentiate salmonella hepatitis from other causes of acute hepatitis. Hepatic pathology is characterized by the presence of typhoid nodules with marked hyperplasia of reticuloendothelial cells. The prognosis is usually good as salmonella hepatitis responds well to a specific antibiotic therapy and juandice resolves with clinical improvement. The clinical course can be severe with a mortality rate as high as 20%, particularly with delayed treatment or in patients with other complications of salmonella infection. As enteric fever is a common infection, the recognition of salmonella hepatitis is of clinical importance. 相似文献
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We have adopted the flash method to the measurement of thermal diffusivity α of polymers in the temperature range 100–400K. The pulsed radiant energy from a flash tube is applied to the ‘front’ side of a suspended sample disc, and α is deduced from the exponential decay time constant of the subsequent transient temperature difference between the ‘front’ and the ‘back’ side, while correction against radiation loss is made by measuring the much longer decay time of the back-side temperature. Calibration runs on polycarbonate (PC) samples of several thicknesses show that the method is quick, precise and fairly accurate, and the results obtained are in reasonable agreement with previous determinations. We have also carried out measurements on polyoxymethylene (POM), poly (vinylidene fluoride) (PVF2) and poly (ethylene terephthalate) (PET) and computed their thermal conductivities. Results on POM and PVF2, which are semicrystalline, are analysed in the framework of several two-phase models, and the effect of crystallization (produced by annealing) on the glass transition behaviour of PET has also been studied. 相似文献
45.
Dynamic mechanical measurements between — 180°C and 180°C were made on both isotropic and drawn samples of polybutene-1 (PB-1) and poly-4-methylpentene-1 (P4MB1) over a wide frequency range by the use of a torsional pendulum (0.3–3 Hz), a viscoelastic spectrometer (5–90 Hz) and ultrasonic technique (3 MHz). The relaxation peaks were identified and the associated activation energies determined from Arrhenius plots. For PB-1 it was observed that orientation reduces the height and shifts up the temperature of the αa-peak associated with large scale main-chain motion in the amorphous regions, but has little effect on the β-peak associated with side-group motion. In addition to the αa and β relaxations a high-temperature crystalline relaxation (αc) is also observed in P4MP1. For both the αc and β relaxations the mechanical loss at 45° to the draw direction is much larger than that at 90°, which indicates that shear processes are involved in these relaxations. 相似文献
46.
The heat capacities of two copolymers of chlorotrifluorethylene and vinylidene fluoride, one 30:70 mol % and the other 44:56 mol % in composition, were measured in an adiabatic calorimeter from 80 to 340 K. The glass-transition points Tg observed at 256 and 269 K for the 30:70 and 44:56 samples, respectively, closely agree with the prediction of the theory of Flory and Fox; the accompanying jump of heat capacities at these points was found to be 2.2 cal/K ‘per bead’ for both samples, in fair agreement with the ‘constant ΔCp rule’. A small peak was observed immediately above Tg, and interpreted as a time-dependent effect arising from the lack of equilibrium in the region. The data of the heat capacities were analysed in detail in the framework of the Tarasov model and the principle of additivity, and were found to agree well ( 1–3%) with theory up to the respective glass-transition points in all cases, thus giving support to the validity of the previously published segmental values of heat capacity and of characteristic temperature θ1. 相似文献
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PURPOSE: To evaluate the incidence and specificity of fracture of the first rib as an indicator of child abuse and to determine a mechanism of fracture. MATERIALS AND METHODS: All infants and young children with rib fractures who were seen at the radiology department of an academic medical center over a 2-year period were identified from the radiology data base. RESULTS: Rib fractures were attributed to child abuse in 12 of 35 children identified. Apart from a neonate with congenital osteogenesis imperfecta, only three children, all abused, had first-rib fracture, one bilaterally. Two additional children with first-rib fracture were identified from years prior to the study period. In four children, first-rib fractures were "isolated," without fractures of adjacent bones. CONCLUSION: Child abuse should be considered in cases of pediatric rib fracture, particularly fracture of the first rib. Possible mechanisms for first-rib fracture include impact force, compressive force, and shaking or acute axial load (slamming), which cause an indirect fracture. 相似文献
49.
A de novo satellited short arm of the Y chromosome possibly resulting from an unstable translocation
A satellited long arm of the Y chromosome (Yqs) is considered a normal variation, whereas the presence of a satellite on the short arm of the Y (Yps) has never been described in the literature. A Yps chromosome could be clinically significant if the translocation resulting in Yps has relocated the testis-determining gene, SRY, to another chromosome. A carrier of such a translocation would therefore be at increased risk for having XX male and XY female offspring. Here we describe the first reported case of de novo Yps present in a phenotypically normal male. This Yps chromosome was positive for C-banding and nucleolus organizer region (NOR) staining and showed a hybridization signal for the beta-satellite sequence. Fluorescence in situ hybridization (FISH) analysis indicated that SRY was retained on the Yps and the translocation breakpoint on Yps was distal to the pseudoautosomal region. At prenatal diagnosis, a normal appearing Y chromosome was found in his son, and thus the satellite on Yps was lost during meiotic Xp-Yp pairing. This Yps chromosome was likely the product of an "unstable" translocation. 相似文献
50.
The efficacy of targeted therapeutics such as immunotoxins is directly related to both the extent of distribution achievable and the degree of drug internalization by individual cells in the tissue of interest. The factors that influence the tissue distribution of such drugs include drug transport; receptor/drug binding; and cellular pharmacology, the processing and routing of the drug within cells. To examine the importance of cellular pharmacology, previously treated only superficially, we have developed a mathematical model for drug transport in tissues that includes drug and receptor internalization, recycling, and degradation, as well as drug diffusion in the extracellular space and binding to cell surface receptors. We have applied this "cellular pharmacology model" to a model drug/cell system, specifically, transferrin and the well-defined transferrin cycle in CHO cells. We compare simulation results to models with extracellular diffusion only or diffusion with binding to cell surface receptors and present a parameter sensitivity analysis. The comparison of models illustrates that inclusion of intracellular trafficking significantly increases the total transferrin concentration throughout much of the tissue while decreasing the penetration depth. Increasing receptor affinity or tissue receptor density reduces permeation of extracellular drug while increasing the peak value of the intracellular drug concentration, resulting in "internal trapping" of transferrin near the source; this could account for heterogeneity of drug distributions observed in experimental systems. Other results indicate that the degree of drug internalization is not predicted by the total drug profile. Hence, when intracellular drug is required for a therapeutic effect, the optimal treatment may not result from conditions that produce the maximal total drug distribution. Examination of models that include cellular pharmacology may help guide rational drug design and provide useful information for whole body pharmacokinetic studies. 相似文献