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排序方式: 共有1410条查询结果,搜索用时 15 毫秒
991.
W Vegetti M Grazia Tibiletti G Testa de Lauretis Yankowski F Alagna E Castoldi M Taborelli T Motta PF Bolis L Dalprà PG Crosignani 《Canadian Metallurgical Quarterly》1998,13(7):1796-1800
Premature ovarian failure is defined as cessation of ovarian function under the age of 40 years and affects approximately 1% of women in the general population. The aetiology of this disorder is still unknown in most cases. Although there have been some reports of familial premature ovarian failure, very little is known about the incidence and inheritance pattern of its idiopathic form. The aims of this study were to investigate the incidence and inheritance pattern of familial premature ovarian failure in a homogeneous group of patients with premature idiopathic menopause and to identify possible clinical differences between patients with the familial and the sporadic form of premature ovarian failure. A total of 71 women were recruited into the study. Clinical assessments and genetic counselling showed that 22 (31%) patients had familial premature ovarian failure, this high incidence strongly suggesting that the disorder is a recognizable heritable entity. There was a statistically significant (P < 0.05) difference in the median age of precocious menopause in patients with sporadic and familial premature ovarian failure (31.0 and 37.5 years of age in the two groups, respectively). Pedigree analysis strongly suggests the existence of a familial pattern of premature ovarian failure with a dominant maternal and/or paternal transmission and incomplete penetrance. In the presence of familial history of premature ovarian failure, reproductive counselling is recommended. 相似文献
992.
The work is bases on an analysis of treatment of 2687 wounded in the abdomen. There are two main groups of factors in mechanogenesis of military injuries of the abdomen: ballistic parameters of gunshot shells and additional injuring factors of mine-explosive ammunition. Bullet wounds prevailed (60.2%), lethality from penetrating abdominal injuries was 31.4%. Laparotomies were performed in 10.7% of the patients on the basis of absolute symptoms of penetrating wounds of the abdomen, in 74.1%--on the basis of analytical signs and in 15.2%--due to results of abdominal paracentesis. The following questions are discussed: the adequacy of the access, reinfusion of the blood accumulated in the abdominal cavity, surgical treatment for gunshot peritonitis, errors in treatment of wounded with abdominal injuries, application of new methods of treatment. Surgical features of traumatic disease and its treatment in wounded with gunshot abdominal injuries are described. 相似文献
993.
F Basolo L Fiore S Calvo V Falcone PG Conaldi G Fontanini AM Caligo G Merlo Y Gluzman A Toniolo 《Canadian Metallurgical Quarterly》1996,73(11):1356-1361
Mammary epithelial cells (MECs) were isolated and cultured from mammary glands of healthy women undergoing reduction mammoplasty. Normal MECs were infected with the transforming hybrid virus adeno-5/SV40. Two transformed epithelial cell lines, M1 and M2, were obtained, characterised phenotypically and studied for the production of and the response to cytokines and growth regulators. In both cell lines, expression of the SV40 large T antigen was associated with loss of interleukin 6 (IL-6) production and responsiveness as well as with down-regulation of IL-8 and transforming growth factor (TGF)-alpha production. Both M1 and M2 cell lines were capable of forming colonies in semisolid media, but upon injection into severe combined immunodeficient (SCID) mice only M2 cells were tumorigenic. DNA synthesis in M1 cells was partially inhibited by serum or TNF-alpha and weakly stimulated by hydrocortisone (HC) and IL-8. In contrast, M2 cells were totally unresponsive to a variety of growth regulators. Both lines overexpressed the p53 protein at levels about 20-fold higher than those observed in primary MEC cultures, but no mutations of the p53 gene could be detected. The date confirm the view that the expression in human mammary cells of different oncogenes - including the SV40 T antigen - is frequently associated with alterations of cytokine production and responsiveness. 相似文献
994.
L Dada F Cornejo Maciel I Neuman PG Mele P Maloberti C Paz C Cymeryng C Finkielstein CF Mendez EJ Podestá 《Canadian Metallurgical Quarterly》1996,22(4):533-539
We investigated the in vitro and in vivo interaction between amiodarone and lidocaine. The interaction on a molecular level was first studied in microsomes from 11 human livers. Close correlations between amiodarone N-monodesethylase activities and (a) the amounts of cytochrome P-4503A4 (CYP3A4), and (b) the rates of lidocaine N-monodesethylation were observed. Lidocaine inhibited amiodarone N-monodesethylation (Ki = 120 microM) competitively; inversely, amiodarone suppressed lidocaine N-monodesethylase activity in the same manner (Ki = 47 microM). Moreover, the metabolite N-monodesethylamiodarone (DEA) was stable and inhibited lidocaine metabolism in a concentration-dependent manner. The in vivo interaction was investigated in 6 cardiac patients. Each of them received a dose of 1 mg/kg lidocaine hydrochloride intravenously (i.v.) on three different occasions: before amiodarone treatment (control), and after cumulative doses of 3 g (phase I) and 13 g (phase II), respectively, amiodarone hydrochloride. The analysis of lidocaine pharmacokinetics showed an increase in lidocaine area under the curve (AUC) when amiodarone was administered, whereas that of N-monodesethylated lidocaine decreased. Moreover, the systemic clearance of lidocaine decreased, while the elimination half-life (t1/2) and the distribution volume at steady state of lidocaine remained unchanged. The pharmacokinetic parameters during phase II were the same as those during phase 1, indicating that the interaction had already occurred early in the loading phase of amiodarone administration. The interaction between amiodarone and lidocaine may be explained by the inhibition of CYP3A4 by amiodarone and/or by its main metabolite DEA. 相似文献
995.
PG Johnston F Geoffrey J Drake D Voeller JL Grem CJ Allegra 《Canadian Metallurgical Quarterly》1996,(12):2148-2154
The combination of 5-fluorouracil (5-FU) and cisplatin (CDDP) has been shown to have synergistic cytotoxicity in human tumours, but the biochemical mechanism for this interaction remains unclear. Therefore, the aim of this study was to investigate the interaction of 5-FU and CDDP in a human colon carcinoma cell line, NCI H548. A 24 h exposure to 5-FU resulted in a 5-FU IC50 value of 24.2 +/- 4.5 microM, Dm 22.6 microM; exposure to CDDP for 2 h resulted in a IC50 value of 20.8 +/- 8.0 microM, Dm 21.9 microM. When cells were exposed simultaneously to 5-FU for 24 h and CDDP for the initial 2 h, or when cells were treated with CDDP for 2 h followed by various concentrations of 5-FU for 24 h, no greater than additive cytotoxicity was observed. In contrast, when cells were treated with 5-FU for 24 h prior to CDDP for 2 h, a greater than additive interaction was noted (5-FU IC50 1.2 +/- 0.6 microM, Dm 1.3 microM, CI 0.45). Thymidine 10 microM partially reversed the growth inhibitory effects of the 5-FU/ CDDP combination. Using both immunological and biochemical assays, no notable differences in the total amount of TS enzyme or the fraction of bound TS enzyme could be detected in the absence or presence of CDDP. No notable differences could be detected in intracellular reduced folate pools, FdUMP or FUTP pools, or 5-FU incorporation into RNA or DNA with the addition of CDDP to 5-FU. DNA fragmentation studies revealed that the combination of 5-FU followed by CDDP demonstrated a greater degree of single-stranded DNA fragments in parental (P = 0.024) and newly synthesised DNA (P = 0.025) compared with the administration of CDDP prior to 5-FU or either drug alone. The increase in smaller DNA fragment size was reversed with the addition of thymidine (10 microM). These findings suggest that the interaction of 5-FU and CDDP is associated with a greater degree of fragmentation of both nascent and parental DNA. 相似文献
996.
PG Simos JI Breier G Zouridakis AC Papanicolaou 《Canadian Metallurgical Quarterly》1998,9(11):2475-2479
The purpose of this study was to extend previous findings of changes in magnetic flux amplitude associated with neuronal currents in the human auditory cortex in response to two-tone stimuli selected from a tone-onset time (TOT) continuum. The results replicated previous findings by indicating a close correspondence between N1m field strength functions and individual perceptual identification curves. In a second experiment event-related fields were recorded in response to two-tone stimuli in which the two sinusoid components always started simultaneously, yet they showed the same energy envelope as the TOT stimuli (amplitude modulated (AM) tokens). The results showed that N1m modulation as a function of TOT could not be accounted for by an effect of AM. The findings suggest that discontinuities in N1m field amplitude functions were the result of interactions between two populations of active neurons each displaying distinct average sound frequency preferences. 相似文献
997.
J Tomkins P Usher JY Slade PG Ince A Curtis K Bushby PJ Shaw 《Canadian Metallurgical Quarterly》1998,9(17):3967-3970
The abnormal assembly and accumulation of neurofilaments (NF) in the perikarya and proximal axons of motor neurones is a characteristic of ALS. Deletions in the KSP repeat region of the NF-H gene have previously been reported in seven patients with sporadic ALS. Here we report the identification of a novel 84 bp insertion in the NF-H gene. This leads to an extra four KSP repeat elements in a highly conserved repetitive region of the gene. Although neurofilament mutations are only associated with a very small proportion of ALS cases, this insertion provides further support of a role for neurofilaments in the pathogenesis of ALS. 相似文献
998.
PG Febbo PW Kantoff E Giovannucci M Brown G Chang CH Hennekens M Stampfer 《Canadian Metallurgical Quarterly》1998,7(12):1075-1078
The p450 hepatic microsomal enzyme system metabolizes exogenous drugs and carcinogens. Debrisoquine hydroxylase (CYP2D6), one member of the p450 hemoproteins, has polymorphic expression leading to poor metabolism of debrisoquine and similar compounds in approximately 7% of Caucasians. The genetic locus for this enzyme has been characterized, and the mutations responsible for the slowed metabolism have been identified. Epidemiological studies of the CYP2D6 phenotype suggest an association between the normal or rapid metabolism phenotype and increased risk of lung and bladder cancer. Preliminary data have also suggested an association with prostate cancer (CaP). We used a PCR-based assay to investigate possible associations between the CYP2D6 B allele, the most common genetic mutation responsible for the poor metabolism phenotype, and CaP. Using genomic DNA isolated from peripheral blood, we genetically typed 571 men with CaP and 767 matched controls, all participants in the Physician's Health Study. Relative to men homozygous for the wild-type allele, heterozygotes for the B allele have an odds ratio of 1.19 (95% confidence interval, 0.94-1.51) for CaP, and men homozygous for the B allele have an odds ratio of 1.37 (95% confidence interval, 0.86-2.20). When analyzed as a trend over zero, one, or two copies of the B allele, there emerges a possible association between the B allele and an increased risk of CaP of borderline statistical significance (P = 0.07). 相似文献
999.
1000.
The nongenomic action of progesterone (P) on capacitated sperm in mediating acrosomal exocytosis operates through transmembrane signal transduction involving increased intracellular calcium ions and modulation of protein kinases and phospholipid metabolism through a second messenger pathway. Conflicting views exist regarding the nature of the nongenomic receptor of P. It is thought to be a cell-surface receptor having the properties of a calcium channel, chloride channel, bicarbonate/chloride exchanger, and gamma aminobutyric acid type A (GABA(A)). In this study, we tried to understand the role of bicarbonate and/or P in inducing membrane perturbations in capacitated and acrosome-reacting spermatozoa. We also attempted to characterize the membrane responses in P-stimulated and bicuculline-poisoned sperm. The presence of a high level of bicarbonate in the medium favored high rotational mobility of lipids and proteins in capacitated sperm. However, the capacitated sperm exhibited low lipid ordering and unaltered protein ordering in response to the high bicarbonate concentration. P and bicuculline appeared to bind to the same or similar binding sites, probably a GABA(A) receptor, eliciting similar motional perturbations in sperm membranes. It appears that both P and bicuculline can induce receptor aggregation and lipid ordering in sperm membranes, which alter the capability of sperm to bind zona pellucida, and that the P action on sperm takes effect through a bicarbonate-dependent signal transduction mechanism. 相似文献