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991.
Epirubicin is known to be metabolized in the liver. Therefore, drugs such as cimetidine, which inhibit the cytochrome P-450 enzyme system or reduce liver blood flow, may reduce the plasma clearance of epirubicin. In a small study, epirubicin 100 mg/m2 every 3 weeks was administered intravenously to eight patients, who also received oral cimetidine (400 mg b.d. for 7 days starting 5 days before chemotherapy) with either the first or second cycles. Epirubicin pharmacokinetics and liver blood flow (idocyanine green clearance) were assessed at each course. The areas under the plasma concentration time curves (AUCs) were used to compare the systemic exposure to epirubicin and its metabolites with each course. The estimated median percentage increase (95% confidence interval CI) in the AUC with cimetidine were: epirubicin 50% (95% CI -18 to 193, epirubicinol 41% (95% CI 1 to 92). Despite the small numbers studied, the increase in the active metabolite epirubicinol was significant (P < 0.05). These changes in exposure were not explained by reduced cytochrome P-450 activity as the 7-deoxy-doxorubicinol aglycone AUC was not reduced (357% increase: 95% CI 17 to 719) or by a decrease in liver blood flow (17% increase: 95% CI -39 to 104). Cimetidine is likely to be coprescribed or self-administered with epirubicin and therefore clinicians should be aware of this potential interaction.  相似文献   
992.
BACKGROUND: Our aim was to infect rats with Helicobacter pylori and to study the effects of the infection on the gastric mucosa in normal and in ulcer-operated rats. METHODS: A mouse-adapted H. pylori (cagA-, VacA-) strain was inoculated into 23 rats. Another 20 uninfected rats served as controls. Two months later a gastric ulcer was induced in some rats. The animals were killed 3, 6, or 15 days after the ulcer operation. Tissues were taken for histology and for culture of H. pylori. Serum antibodies were determined. RESULTS: All inoculated rats were infected by H. pylori after 2 months, mainly in the antrum. In these rats a mild to moderate chronic inflammation and a significantly increased frequency of apoptotic cells were observed in the antrum and in the ulcer margin, the ulcer healing was delayed, and the serum level of H. pylori-specific Ig was increased. CONCLUSIONS: H. pylori infection in rats was successful and was accompanied by a mild to moderate mucosal inflammation. Gastric ulcer healing was delayed in infected rats, probably due to the inflammation and the increased apoptosis in epithelium.  相似文献   
993.
An extraordinary level of length heterogeneity was found in the ribosomal DNA (rDNA) of an asexual hybrid Neotyphodium grass endophyte, isolate Lp1. This hybrid Neotyphodium endophyte is an interspecific hybrid between two grass endophytes, Neotyphodium lolii, and a sexual form, Epichl?e typhina, and the length heterogeneity was not found in either of these progenitor species. The length heterogeneity in the hybrid is localized to the intergenic spacer (IGS) and is the result of copy-number variation of a tandemly repeated subrepeat class within the IGS, the 111-/119-bp subrepeats. Copy number variation of this subrepeat class appears to be a consequence of mitotic unequal crossing over that occurs between these subrepeats. This implies that unequal crossing over plays a role in the concerted evolution of the whole rDNA. Changes in the pattern of IGS length variants occurred in just two rounds of single-spore purification. Analysis of the IGS length heterogeneity revealed features that are unexpected in a simple model of unequal crossing over. Potential refinements of the molecular details of unequal crossing over are presented, and we also discuss evidence for a combination of homogenization mechanisms that drive the concerted evolution of the Lp1 rDNA.  相似文献   
994.
Simian virus 40 (SV40) DNAs in brain tissue and peripheral blood mononuclear cells (PBMCs) of eight simian immunodeficiency virus-infected rhesus monkeys with SV40 brain disease were analyzed. We report the detection, cloning, and identification of five new SV40 strains following a quadruple testing-verification strategy. SV40 genomes with archetypal regulatory regions (containing a duplication within the G/C-rich regulatory region segment and a single 72-bp enhancer element) were recovered from seven animal brains, two tissues of which also contained viral genomes with nonarchetypal regulatory regions (containing a duplication within the G/C-rich regulatory region segment as well as a variable duplication within the enhancer region). In contrast, PBMC DNAs from five of six animals had viral genomes with both regulatory region types. It appeared, based on T-antigen variable-region sequences, that nonarchetypal virus variants arose de novo within each animal. The eighth animal exclusively yielded a new type of SV40 strain (SV40-K661), containing a protoarchetypal regulatory region (lacking a duplication within the G/C-rich segment of the regulatory region and containing one 72-bp element in the enhancer region), from both brain tissue and PBMCs. The presence of SV40 in PBMCs suggests that hematogenous spread of viral infection may occur. An archetypal version of a virus similar to SV40 reference strain 776 (a kidney isolate) was recovered from one brain, substantiating the idea that SV40 is neurotropic as well as kidney-tropic. Indirect evidence suggests that maternal-infant transmission of SV40 may have occurred in one animal. These findings provide new insights for human polyomavirus disease.  相似文献   
995.
Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder characterized by congenital malformation of the great toes and progressive heterotopic ossification in distinct anatomic patterns. Early preosseous lesions in FOP are clinically and histologically indistinguishable from the lesions of aggressive juvenile fibromatosis (AJF). Although the genetic defect in FOP is unknown, bone morphogenetic proteins (BMPs) 2 and 4 are plausible candidates genes. To determine if there is a difference in BMP 2/4 expression in the early fibromatous lesions of the two conditions, we performed immunohistochemical studies with a monoclonal antibody to BMP 2/4 on the earliest detectable fibromatous lesions of FOP and compared them with histologically identical lesions resected from children who had AJF. Fibromatous cells from the early FOP lesions exhibited immunostaining for BMP 2/4, whereas histologically indistinguishable fibromatous cells from AJF lesions showed no evidence of BMP 2/4 immunostaining. It is incumbent on all physicians who treat patients with suspected fibromatosis to examine the toes to rule out FOP and to avoid unnecessary diagnostic biopsies because surgical trauma induces further bone formation in patients who have FOP. However, if diagnostic confusion still exists and a biopsy is performed, immunostaining with BMP 2/4 antibody may resolve the diagnostic dilemma between FOP and AJF before the appearance of heterotopic ossification is observed in the FOP lesions. Our data suggest that the BMP 2/4 subfamily of secreted proteins may be involved in the pathogenesis of the FOP lesions.  相似文献   
996.
997.
With the many changes that have occurred at the National League for Nursing (NLN) during the past several years, including the formation of the National League for Nursing Accreditation Commission (NLNAC), preparation for an accreditation site visit can be a stress producing event for nursing students, faculty and the nursing administrator. This article is designed for the nursing administrator and faculty who are relatively inexperienced in the accreditation process and provides practice guidelines on how to prepare for the culmination of the preparation process and the actual site visit to the school by a peer review team.  相似文献   
998.
999.
CI2 folds and unfolds as a single cooperative unit by simple two-state kinetics, which enables the properties of the transition state to be measured from both the forward and backward rate constants. We have examined how the free energy of the transition state for the folding of chymotrypsin inhibitor 2 (CI2) changes with pH and temperature. In addition to the standard thermodynamic quantities, we have measured the overall acid-titration properties of the transition state and its heat capacity relative to both the denatured and native states. We were able to determine the latter by a method analogous to a well-established procedure for measuring the change in heat capacity for equilibrium unfolding: the enthalpy of activation of unfolding at different values of acid pH were plotted against the average temperature of each determination. Our results show that the transition state of CI2 has lost most of the electrostatic and van der Waals' interactions that are found in the native state, but it remains compact and this prevents water molecules from entering some parts of the hydrophobic core. The properties of the transition state of CI2 are then compared with the major folding transition state of the larger protein barnase, which folds by a multi-state mechanism, with the accumulation of a partly structured intermediate (Dphys or I). CI2 folds from a largely unstructured denatured state under physiological conditions via a transition state which is compact but relatively uniformly unstructured, with tertiary and secondary structure being formed in parallel. We term this an expanded pathway. Conversely, barnase folds from a largely structured denatured state in which elements of structure are well formed through a transition state that has islands of folded elements of structure. We term this a compact pathway. These two pathways may correspond to the two extreme ends of a continuous spectrum of protein folding mechanisms. Although the properties of the two transition states are very different, the activation barrier for folding (Dphys-->++) is very similar for both proteins.  相似文献   
1000.
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