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排序方式: 共有5971条查询结果,搜索用时 15 毫秒
941.
942.
943.
NI Perrone-Bizzozero TV Isaacson GM Keidan C Eriqat KF Meiri DD Savage AM Allan 《Canadian Metallurgical Quarterly》1998,71(5):2104-2111
Consumption of moderate quantities of ethanol during pregnancy produces deficits in long-term potentiation in the hippocampal formation of adult offspring. Protein kinase C (PKC)-mediated phosphorylation of the presynaptic protein GAP-43 is critical for the induction of long-term potentiation. We tested the hypothesis that this system is affected in fetal alcohol-exposed (FAE) rats by measuring GAP-43 phosphorylation and PKC activity in the hippocampus of adult offspring of rat dams that had consumed one of three diets throughout gestation: (a) a 5% ethanol liquid diet, which produced a maternal blood ethanol concentration of 83 mg/dl (FAE); (b) an isocalorically equivalent 0% ethanol diet (pair-fed); or (c) lab chow ad libitum. Western blot analysis using specific antibodies to PKC-phosphorylated GAP-43 revealed that FAE rats had an approximately 50% reduction in the proportion of phosphorylated GAP-43. Similarly, we found that PKC-mediated incorporation of 32P into GAP-43 was reduced by 85% in hippocampal slices from FAE rats compared with both control groups. FAE animals also showed a 50% reduction in total hippocampal PKC activity, whereas the levels of six major PKC isozymes did not change in any of the diet groups. These results suggest that GAP-43 phosphorylation deficits in rats prenatally exposed to moderate levels of ethanol are not due to alterations in the expression of either the enzyme or substrate protein, but rather to a defect in kinase activation. 相似文献
944.
AM Kelly 《Canadian Metallurgical Quarterly》1998,15(4):254-256
OBJECTIVES: (1) To establish the proportion of blood cultures that yield a positive microbiological culture. (2) To determine what proportion of blood cultures taken in the emergency department impact on patient management. (3) To develop guidelines for the appropriate ordering of blood cultures from patients in the emergency department (ED). METHODS: Retrospective review of all blood cultures taken in the ED of a metropolitan teaching hospital between 26 September 1995 and 30 June 1996. RESULTS: One thousand and sixty two blood cultures were taken from patients in the ED during the study period. Ninety two (9%) returned a positive microbiological culture. Of these, 52 (5%) were "true" positives and 18 (1.6%) resulted in changes in management. CONCLUSIONS: Blood cultures taken in the ED rarely yield positive cultures. Only 1.6% of blood cultures taken in the ED impact on management of patients. Simple strategies could reduce the number of blood cultures ordered with little prospect of patient compromise. 相似文献
945.
AM Tromans M Mecci FH Barrett TA Ward DJ Grundy 《Canadian Metallurgical Quarterly》1998,36(7):481-484
Transurethral electrovaporization of the prostate (TVP) is a new minimally invasive procedure for treatment of enlargement of prostate. Between April 1996 and September 1997, TVP was carried out in 109 cases with symptoms of lower urinary tract obstruction. A Stortz spike electrode and a Stortz vapor cutting electrode were used for vaporization electrodes. Efficacy parameters evaluated included International Prostate Symptom Score, peak uroflow and postvoid residual volume. By September 1997, 32 cases (spike electrode) and 33 cases (vapor cutting electrode) could be followed up and evaluated. They have shown both subjective and objective voiding improvement. The improvements in subjective symptom scores and objective voiding parameters were not significantly different between the two electrode groups. Early complications included urinary retention, intraoperative burn, stress incontinence, blood transfusion and postoperative hemorrhage. Late complications included urethral stricture, bladder neck contracture and bladder stone. TVP was found to have several advantages, particularly minimal bleeding and the low incidence of postoperative morbidity. The technique is simple and symptoms improve at an early stage following surgery. This study demonstrates that TVP is a safe and effective modality for treatment of BPH. However, long-term studies with larger numbers of patients are needed. 相似文献
946.
The present study examined the relationship between acculturation, alcohol consumption and AIDS-related risky sexual behavior in a national probability sample of 533 African American women. Results indicated that women who were the heaviest drinkers were also the least acculturated. However, women most likely to engage in risky sexual behavior, including having multiple partners, being nonmonogamous or in a nonmonogamous relationship, and being nonmonogamous or in a nonmonogamous relationship and not using a condom consistently, were high in acculturation rather than low. Alcohol use proved related to risky sexual behavior when considered in conjunction with respondents' level of acculturation. Women at risk for contracting AIDS were not low acculturated African American women who drank heavily, but high acculturated African American women. Findings from this study extend our understanding of risk and contain implications for research and prevention efforts in the area of alcohol use and AIDS-related sexual behavior among African American women. 相似文献
947.
7-beta-D-Ribofuranosylxanthine, a previously unreported isomer of xanthosine, was prepared in four steps from 7-benzylxanthine. The procedure, which involves the use of pivaloyloxymethyl groups to protect the xanthine ring, was also applied to preparation of some 1-N-alkyl derivatives of 7-ribosylxanthine. Adenosine receptor affinity for these compounds was determined. 7-beta-D-Ribofuranosylxanthine was found to have higher affinity and greater selectivity for the A1 receptor than previously reported xanthine nucleosides, and to be a partial agonist. 相似文献
948.
JA Lawson W Nguyen AF Bleasel JK Pereira S Vogrin MJ Cook AM Bye 《Canadian Metallurgical Quarterly》1998,39(12):1345-1349
PURPOSE: The role of quantitative magnetic resonance imaging (MRI) in evaluation of childhood epilepsy remains poorly defined, with minimal published data. Previous work from our center questioned the specificity of hippocampal asymmetry (HA) in an outpatient group whose epilepsy was defined by using clinical and interictal data only. By using childhood volunteer controls and defining epilepsy syndromes using video-EEG monitoring, we readdressed the utility of HA in differentiating mesial temporal lobe epilepsy (MTLE) from other partial and generalized epileptic syndromes in children. METHODS: Seventy children were enrolled; entry criteria were age younger than 18 years with predominant seizure type recorded on video-EEG telemetry with volumetric MRI in all cases. Thirty healthy child volunteers had volumetric MRI. Epilepsy syndrome classification was according to ILAE. RESULTS: Control data revealed symmetric hippocampi, mean smaller/larger ratio of 0.96 (0.95-0.97, 95% CI) with no gender or right/left predominance. Overall 23% of patients had significant HA. Mean hippocampal ratio for MTLE was 0.78 (95% CI, 0.70-0.86), significantly lower than controls and from all other epilepsy syndromes. HA was highly specific (85%) to the syndrome of MTLE. Other potential epileptogenic lesions were found in 27 (39%) patients, lowest yield in frontal and mesial temporal syndromes. Dual pathology was present in 10% of patients. There was no significant association between HA and risk factors. CONCLUSIONS: In this study, we found that HA in children with a well-defined epilepsy syndrome is highly sensitive and specific for MTLE. Whether this will correlate with surgical outcome, as in adults, is the subject of ongoing study. 相似文献
949.
N Kundu R Dorsey MJ Jackson P Guiterrez K Wilson S Fu K Ramanujam E Thomas AM Fulton 《Canadian Metallurgical Quarterly》1998,76(5):713-719
Transfection of cDNA for IL-10 into line 66.1 murine mammary tumor cells results in marked suppression of tumor growth and metastasis. Others have reported that nitric oxide has potent antitumor activity and IL-10 is known to regulate the inducible isoform of nitric oxide synthase (iNOS) expressed in macrophages. We identified nitric oxide production in mammary tumors as indicated by electron paramagnetic resonance detection of nitric oxide-hemoglobin (NO-Hb). IL-10 expression resulted in elevated levels of NO-Hb in mammary tumors. Immunohistochemical examination of mammary tumors for iNOS protein revealed few positively staining cells in parental or control neo-transfected tumors but strong iNOS staining in all IL-10 transfected tumors, consistent with the NO-Hb data. To determine if mammary epithelial tumor cells themselves, express nitric oxide synthase activity, cultured tumor cells were treated with pro-inflammatory cytokines and nitrite accumulation was assessed in the conditioned medium. All IL-10 producing cell lines accumulated uM concentrations of nitrite in response to short term (24 hr) cytokine stimulation. Cells not expressing IL-10 (parental and neo-transfectants) accumulated no nitrite under similar culture conditions. After longer stimulation (48 hr), parental and 66-neo cells accumulated lower amounts of nitrite. IL-10 gene transfer is associated with increased iNOS protein expression and enzymatic activity detected both in vitro and in vivo. Our findings suggest that the antimetastatic and antitumor activity of IL-10 is related to enhanced production of nitric oxide. 相似文献
950.
EH Uhlenhuth PE Alexander GM Dempsey W Jones BS Coleman AM Swiontek 《Canadian Metallurgical Quarterly》1998,47(1-3):183-190
Heart sounds produce an incessant noise during lung sounds recordings. This noise severely contaminates the breath sounds signal and interferes in the analysis of lung sounds. In this paper, the use of a wavelet transform domain filtering technique as an adaptive de-noising tool, implemented in lung sounds analysis, is presented. The multiresolution representations of the signal, produced by wavelet transform, are used for signal structure extraction. In addition, the use of hard thresholding in the wavelet transform domain results in a separation of the nonstationary part of the input signal (heart sounds) from the stationary one (lung sounds). Thus, the location of the heart sound noise (1st and 2nd heart sound peaks) is automatically detected, without requiring any noise reference signal. Experimental results have shown that the implementation of this wavelet-based filter in lung sound analysis results in an efficient reduction of the superimposed heart sound noise, producing an almost noise-free output signal. Due to its simplicity and its fast implementation the method can easily be used in clinical medicine. 相似文献