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排序方式: 共有2382条查询结果,搜索用时 15 毫秒
41.
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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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
44.
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
45.
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
46.
CL Quinn 《Canadian Metallurgical Quarterly》1998,26(9):665-667
Failure to achieve anesthesia can be a significant problem in the day-to-day practice of dentistry. The usual strategy following an anesthetic failure is to reinject. Therefore, a good understanding of conventional anesthetic techniques is important. But the practitioner also needs to have a broad armamentarium of injection strategies available for the "difficult-to-anesthetize cases". These strategies include the use of 5 percent lidocaine, intrapulpal injection, periodontal ligament injection and intraosseous injection. This paper will be a brief discussion of those techniques with an emphasis on the intraosseous injection. 相似文献
47.
PA Stumbles JA Thomas CL Pimm PT Lee TJ Venaille S Proksch PG Holt 《Canadian Metallurgical Quarterly》1998,188(11):2019-2031
Consistent with their role in host defense, mature dendritic cells (DCs) from central lymphoid organs preferentially prime for T helper cell type 1 (Th1)-polarized immunity. However, the "default" T helper response at mucosal surfaces demonstrates Th2 polarity, which is reflected in the cytokine profiles of activated T cells from mucosal lymph nodes. This study on rat respiratory tract DCs (RTDCs) provides an explanation for this paradox. We demonstrate that freshly isolated RTDCs are functionally immature as defined in vitro, being surface major histocompatibility complex (MHC) II lo, endocytosishi, and mixed lymphocyte reactionlo, and these cells produce mRNA encoding interleukin (IL)-10. After ovalbumin (OVA)-pulsing and adoptive transfer, freshly isolated RTDCs preferentially stimulated Th2-dependent OVA-specific immunoglobulin (Ig)G1 responses, and antigen-stimulated splenocytes from recipient animals produced IL-4 in vitro. However, preculture with granulocyte/macrophage colony stimulating factor increased their in vivo IgG priming capacity by 2-3 logs, inducing production of both Th1- and Th2-dependent IgG subclasses and high levels of IFN-gamma by antigen-stimulated splenocytes. Associated phenotypic changes included upregulation of surface MHC II and B7 expression and IL-12 p35 mRNA, and downregulation of endocytosis, MHC II processing- associated genes, and IL-10 mRNA expression. Full expression of IL-12 p40 required additional signals, such as tumor necrosis factor alpha or CD40 ligand. These results suggest that the observed Th2 polarity of the resting mucosal immune system may be an inherent property of the resident DC population, and furthermore that mobilization of Th1 immunity relies absolutely on the provision of appropriate microenvironmental costimuli. 相似文献
48.
Mouse pancreatic islet grafts under the kidney capsule of syngeneic hosts were removed and perifused in vitro 1-40 weeks after the transplantation. In comparison with fresh islets, 12- to 40-week-old grafts exhibited an attenuated first phase of glucose-stimulated insulin release. In grafts 1, 12, 28, or 40 weeks old, but not in fresh islets, the mean secretory rate during the initial 10 min of stimulation was significantly lower than that during the subsequent 15 min. When expressed in relation to insulin content, the insulin output in response to 11 mmol/L glucose was no less from grafts than from fresh islets; in grafts 12 or 40 weeks old at 16.7 mmol/L glucose, the fractional output above baseline was significantly diminished during the initial 10 min, but not subsequently. Immediately on switching from basal to stimulatory glucose concentration, there was a transient drop in insulin secretion from the grafts, especially after more than 12 weeks of transplantation and in response to 16.7, as compared with 11, mmol/L glucose. When glucose was switched back from stimulatory to basal concentration, grafts also frequently exhibited a transient increase in the insulin secretory rate. Neither initial drops nor "off responses" were seen in untransplanted islets. The modifications of the secretory dynamics in islet grafts suggest that transplantation influences the balance between the stimulatory and inhibitory influences of glucose on the beta-cell's secretory machinery. 相似文献
49.
50.
M Pazianas M Zaidi CL Huang BS Moonga VS Shankar 《Canadian Metallurgical Quarterly》1993,192(3):1100-1105
We demonstrated previously that osteoclasts possess a divalent cation-sensitive "receptor", the Ca2+ receptor. Activation of the Ca2+ receptor by the surrogate cation Ni2+ was shown to elicit an increase in cytosolic [Ca2+] to a peak value followed by an exponential decline. In the present study we examined the influence of surface membrane voltage on the kinetics of Ca2+ receptor inactivation. The K+ ionophore, valinomycin was applied to intercept the declining phase of the cytosolic [Ca2+] transient elicited by application of between 50 microM- and 5 mM-[Ni2+]. This resulted in a sustained elevation of cytosolic [Ca2+] or even a 'hump' followed by a gradual decline. Such a kinetic alteration persisted in a Ca(2+)-free solution, but was abolished in high extracellular [K+] (105 mM). Thus, we demonstrate for the first time to our knowledge, a modulatory effect of membrane potential on the function of the osteoclast Ca2+ receptor. 相似文献