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71.
M Kumar R Prashad A Kumar R Sharma SK Acharya TK Chattopadhyay 《Canadian Metallurgical Quarterly》1998,45(24):2027-2032
Fifty consecutive patients with surgical obstructive jaundice were evaluated prospectively with ultrasonography (US), computed tomographic scans (CT scan) and cholangiography-percutaneous transhepatic cholangiography (PTC) or endoscopic retrograde cholangio-pancreaticography (ERCP). The diagnostic accuracy of ultrasound in defining the level of obstruction was 86% as compared to 86% and 94.8% for CT scan and cholangiography, respectively. To measure the etiology of the obstruction, the accuracy of ultrasound, CT scan and cholangiography were 84%, 86% and 75%, respectively. The sensitivity of CT scans and cholangiography in the diagnosis of choledocholithiasis was 100%, 81.8% and 90%, respectively, whereas specificity was 97%, 100% and 100%, respectively. Sensitivity for a diagnosis of malignant disease was 100% for both US and CT scans whereas specificity was 90% and 81%, respectively. Ultrasonography as a single radiological investigation is sufficient in the evaluation of the majority of patients with surgical obstructive jaundice. CT scan and cholangiography should be done only when US gives equivocal findings or if concomitant therapeutic procedures like basketing and stenting are also planned. 相似文献
72.
The effects of deprenyl on methamphetamine-induced dopamine depletions were studied in mice. Four SC injections of 12.5 mg/kg of methamphetamine at two-hour intervals caused substantial (72-82%) and long-lasting depletions of striatal dopamine. Pretreatment with either 25 or 40 mg/kg of deprenyl did not significantly alter the magnitude of this depletion. These results indicate that, unlike what is observed following MPTP, there is no protection afforded dopaminergic cells by deprenyl pretreatment in the methamphetamine model of parkinsonism. 相似文献
73.
74.
Local and systemic activation of coagulation is frequently associated with bacterial sepsis. The coagulopathy is due, at least in part, to expression of tissue factor (TF) by monocytes and macrophages. The purpose of this study was to evaluate the expression of procoagulant activity by bovine alveolar macrophages, leukocytes and platelets, and to determine the relative potency of three chemical inhibitors of TF expression (pentoxifylline, retinoic acid, and cyclosporin A). Bovine alveolar macrophages were stimulated with lipopolysaccharide (LPS) derived from Pasteurella haemolytica or recombinant bovine tumour nervous factor (TNF) and dose- and time-dependent effects on TF expression were studied. LPS and TNF induced TF expression in alveolar macrophages and LPS treatment of whole blood induced TF expression in mononuclear cells. Neutrophils and platelets also expressed procoagulant activity, but this activity was not inhibited by anti-bovine TF monoclonal antibody. Pentoxifylline (40 mumol/L), retinoic acid (0.01 mmol/L) and cyclosporin A (0.08 mumol/L) inhibited TF expression when added concurrently with LPS or TNF, but not when added 4 h after stimulation. TF mRNA was not detected in unstimulated alveolar macrophages by Northern blot analysis. In contrast, exposure to LPS or TNF for 6 h induced marked expression of TF mRNA, which was inhibited by treatment with pentoxifylline, retinoic acid and cyclosporin A. Expression of TNF by alveolar macrophages stimulated with LPS was also inhibited by these compounds. Our results indicate that procoagulant activity expressed by alveolar macrophages and monocytes is associated with expression of TF, whereas procoagulant activity expressed by neutrophils and platelets is not. The concentrations of pentoxifylline and retinoic acid necessary for inhibition of TF expression in vitro may not be achievable in vivo owing to their toxic effects. However, the in vitro concentration of cyclosporin A that inhibited TF expression did not exceed the plasma concentration observed in humans, and therefore may be useful for inhibition of TF expression in vivo. 相似文献
75.
Pollen development and male gametogenesis are critically dependent upon cell polarization leading to a highly asymmetric cell division termed pollen mitosis I. A mutational approach was adopted in Arabidopsis thaliana to identify genes involved these processes. Four independent gemini pollen mutants were isolated which produce divided or twin-celled pollen. The gemini pollen1 mutant was characterized in detail and shown to act gametophytically resulting in reduced transmission through both sexes. gemini pollen1 showed an incompletely penetrant phenotype resulting in equal, unequal and partial divisions at pollen mitosis I. The division planes in gemini pollen1 were shown to be aligned with the polar axis (as in wild type) and evidence was obtained for incomplete nuclear migration, which could account for altered division symmetry. gemini pollen1 also showed division phenotypes consistent with spatial uncoupling of karyokinesis and cytokinesis suggesting that GEMINI POLLEN1 may be required for the localization of phragmoplast activity. Cell fate studies showed that in both equal and unequal divisions a vegetative cell marker gene was activated in both daughter cells. Daughter cells with a range of intermediate or hybrid vegetative/generative cell fates suggests that cell fate is quantitatively related to cell size. The potential mode of action of GEMINI POLLEN1 and its effects on cell fate are discussed in relation to proposed models of microspore polarity and cell fate determination. 相似文献
76.
The aim of this cross-sectional study which took place in a hypertension clinic at a district general hospital in Denmark was to make a pragmatic definition of white coat hypertension. A total of 420 patients were referred consecutively from general practice with newly diagnosed untreated essential hypertension and 146 normal subjects were drawn at random from the Danish national register. The following measurements were taken: office blood pressure; 24-h ambulatory blood pressure (BP) monitoring; echocardiography with determination of left ventricular mass index and relative wall thickness; and early morning urine albumin/creatinine ratios. Four different cut-off levels were studied. An ambulatory daytime BP of 135.6/90.4 mm Hg was found to correspond to an office BP of 140/90 mm Hg in normal controls; used as a cut-off level in patients with newly diagnosed hypertension it separated 19% as white coat hypertensives. The end-organ involvement of these white coat hypertensives differed significantly from those with established hypertension but not from the normal controls. Lower cut-off levels were less efficient in this respect, as was the case when the systolic BP was not taken into account. In conclusion a pragmatic definition of white coat hypertension should--apart from well-established hypertensive office measurements--include a cut-off level close to 135/90 mm Hg ambulatory daytime BP. 相似文献
77.
WW Harcum GW Skinner M Altekar SK Joneja PE Barnum JH Guo 《Canadian Metallurgical Quarterly》1998,24(10):911-918
The objective of the research described here was to develop a set of predictive models that would be used to show the performance of hydroxypropylcellulose as a pharmaceutical tablet binder. A statistically designed set of experiments was used to relate tablet formulation to functionality. It was found that the binder level affected both hardness and dissolution time. Useful predictive models were generated for tablet hardness and dissolution time as a function of the binder or binder-drug ratio. The optimal formulation can be predicted from this study, and will depend upon the combination of desired hardness and the dissolution time for a particular drug. 相似文献
78.
Human glioblastoma multiforme cell lines, brain tumor biopsy tissue, and normal human fetal brain synthesize interleukin (IL)-6 and IL-6 receptor (IL-6R). Neither of these is expressed in human neurons or neuroblastoma cell lines in culture. Astrocytes from fetal brain grown in culture retain the ability to synthesize IL-6 but do not express IL-6R as inferred from RT-PCR and Southern blot studies. Coexpression of IL-6 and IL-6R in the glioblastoma cell line U87MG is confirmed by immunofluorescence staining. Both specific monoclonal antibodies against IL-6 and IL-6R and antisense oligonucleotide to IL-6 mRNA inhibit the growth of U87MG cells in culture, suggesting the existence of a functional autocrine growth loop. Anti-IL-6 antibodies also inhibit the growth of glioblastoma cell lines U373 and U118. The expression of IL-6 by human fetal astrocytes in culture is highly suggestive of its role as an oncofetal protein responsible for rapid proliferation of fetal and tumor cells but not cells of adult brain. 相似文献
79.
SK Kumanyika JR Landis YL Matthews-Cook SL Almy SJ Boehmer 《Canadian Metallurgical Quarterly》1998,148(6):528-538
Recent blood pressure trends reflect progress in hypertension control, but prevalent drug therapy precludes direct estimation of the component due to primary prevention. In data gathered on persons aged 35-74 years in three successive US health examination surveys (1960-1980), systolic blood pressure levels assuming no drug therapy were imputed by reassigning blood pressure to the upper end of the distribution for respondents reporting use of antihypertensive medication. Blood pressure was partitioned into four ordinal categories based on weighted percentiles of the 1960-1962 distributions for 35- to 44-year-old males and females who reported no use of antihypertensive medication. Cumulative logit models (alpha = 0.01) were used to estimate age- and sex-specific trends for blacks and whites within two strata (<25 or > or =25) of body mass index (BMI) (weight (kg)/height (m)2). Before imputation, systolic blood pressure decreased between 1960 and 1980; after imputation, significant decreases remained only in 35- to 44-year-olds. Strong associations of black race and BMI > or =25 with higher blood pressures were present in models with and without drug therapy. Thus, according to the models, there has been little progress in decreasing racial or BMI-related blood pressure differentials. Above the age of 44 years, blood pressure trends were largely attributable to medication use. In contrast, data for 35- to 44-year-olds suggest progress in primary prevention. 相似文献
80.
BL Daniel YF Yen GH Glover DM Ikeda RL Birdwell AM Sawyer-Glover JW Black SK Plevritis SS Jeffrey RJ Herfkens 《Canadian Metallurgical Quarterly》1998,209(2):499-509
The cochleo- and tonotopic organization of the second auditory area (AII) was investigated in cats anaesthetized with pentobarbital using a combination of macro- and microelectrode recording technique. The results obtained following electrical stimulation of the neural fibres innervating different regions of the organ of Corti indicate the existence of two complete representations of the cochlea in area AII: one in the dorsocaudal portion, the other in its ventrorostral portion. These two cortical representations of the cochlea differ in size and spatial orientation. The dorsocaudal projection area extends over a distance of 2.6-3.2 mm from the basal to the apical focus and is arc-shaped. The spatial orientation of cochlea representation within the dorsocaudal region of AII is similar to that described in AI, in that stimulation of the cochlea base results in maximal responses in the more rostral portion of AII and stimulation of the apex evokes cortical responses more caudally. The ventrorostral region within AII is smaller (1.4-2.5 mm length), and has the opposite cochleotopic orientation (base and apex stimulation represented caudally and rostrally, respectively). In both AII zones, there was a proportionally greater cortical representation of basilar membrane than of middle and apical portions. Although two distinct zones with the overall cochleotopic pattern described above were noted in all cats, their precise size and location considerably varied in different animals. Using microelectrode recordings, a cortical tonotopic organization can be observed that was consistent with and expanded on the earlier cochleotopic data. Within the dorsocaudal region of AII, neurons with higher best frequency responses were located in more rostral regions, while those with lower best frequencies were located caudally. An orderly progression of best frequency responses was noted as serial recordings carried out along the full extent of the representation. Neurons within the ventrorostral region of AII also displayed an orderly progression of best frequencies, but in the opposite direction, with higher best frequencies noted more caudally and lower best frequencies more rostrally. 相似文献