共查询到20条相似文献,搜索用时 15 毫秒
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DL Earnest E Dorsch J Jones DE Jennings PA Greski-Rose 《Canadian Metallurgical Quarterly》1998,93(2):238-243
Various signal processing techniques have been proposed to improve spectral estimation of closely spaced sinusoids in the presence of noise. This paper exploits frequency prior knowledge information to extract single peaks in magnetic resonance spectra, corresponding to metabolites of interest, by means of a highly selective finite impulse response filter. Thereafter the estimation of the parameters of the peaks is carried out using a singular-value-decomposition-based method known as HTLS. The new technique improves the performance of fully automated magnetic resonance spectroscopy data quantification when frequency prior knowledge is available. 相似文献
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G Boccuzzi E Brignardello M Di Monaco V Gatto L Leonardi A Pizzini M Gallo 《Canadian Metallurgical Quarterly》1994,70(6):1035-1039
Adrenal androgens show a dual and apparently opposite effect on the growth of oestrogen-responsive breast cancer: they stimulate growth on their own, but counteract the growth-stimulatory effect of oestrogens. Focusing on the inhibitory action we have studied the effects of 5-en-androstene-3 beta,17 beta-diol (ADIOL) on the growth of oestrogen-responsive MCF-7 breast cancer cells in the presence of oestrogens (oestradiol and diethylstilboestrol), antiestrogens (tamoxifen) and antiandrogens (hydroxyflutamide). The inhibition of oestrogen-stimulated growth, attained with nanomolar concentrations of ADIOL, was not modified by increasing concentrations of diethylstilboestrol up to 100 nM. This inhibition was counteracted by antiandrogens, which were unable to block the ADIOL stimulatory effect in steroid-free medium. On the other hand, in the presence of tamoxifen ADIOL showed an additive antiproliferative activity also in steroid-free medium, rather than the usual stimulatory effect. These results suggest that ADIOL stimulates breast cancer cell growth via oestrogen receptors, but inhibits oestrogen-stimulated growth via androgen receptors. 相似文献
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V Mijatovic P Kenemans JC Netelenbos ER Peters-Muller GJ van Kamp GA Voetberg PH van de Weijer MJ van der Mooren 《Canadian Metallurgical Quarterly》1997,82(11):3543-3547
Lipoprotein(a) [Lp(a)] is an independent risk factor for atherosclerosis. Serum Lp(a) concentrations increase after menopause, and postmenopausal estrogen replacement appears to decrease Lp(a) levels. In a randomized, double blind study, we examined the effects of 6-month treatment with daily 17 beta-estradiol (E2; 2 mg, orally) continuously combined with one of four dosages [2.5 mg (n = 41), 5 mg (n = 38), 10 mg (n = 38), and 15 mg (n = 20)] of dydrogesterone on fasting serum Lp(a) concentrations in 137 healthy postmenopausal women. At baseline, no significant differences were noted among the four treatment groups. During the study period of 6 months the median serum Lp(a) concentration decreased significantly from 128 mg/L (range, 5-1660) to 110 mg/L (range, 1-1530) in the total population, corresponding to a reduction of 13% (P < 0.001). The percent changes in serum Lp(a) correlated positively with the percent changes in serum E2 at 3 as well as 6 months of therapy (r = 0.38; P < 0.001 and r = 0.35; P < 0.001, respectively). A dose response of dydrogesterone on serum Lp(a) was not found. In addition, serum lipids and (apo)lipoproteins improved significantly in all four treatment groups. In conclusion, oral E2 continuously combined with dydrogesterone has beneficial effects on the lipid and lipoprotein profile and is effective in lowering Lp(a) concentrations in postmenopausal women. 相似文献
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The focus of this review is hormone replacement therapy (HRT) with continuous oral 17 beta-estradiol (herein referred to as estradiol) 2 mg/day plus sequential oral dydrogesterone 10 or 20 mg/day for 14 days of each 28-day cycle. According to data from nonblind trials, this regimen relieves climacteric symptoms, preserves bone mineral density (BMD) and improves the cardiovascular risk profile in postmenopausal women. Increases in mean BMD in the lumbar spine of 2.4 to 6.4% have been reported after 2 years' treatment. The effect on BMD of oral estradiol plus sequential dydrogesterone was similar to that achieved with transdermal estradiol plus sequential oral dydrogesterone or with oral tibolone. Good protection against endometrial hyperplasia and cancer is provided by the dydrogesterone component. Cyclical vaginal bleeding occurs in most treatment cycles, but is generally light to moderate and the time of onset is highly predictable. Noncyclical bleeding occurs in < 10% of cycles. Mean serum high density lipoprotein-cholesterol levels are increased and low density lipoprotein-cholesterol levels are decreased during treatment with oral estradiol plus sequential dydrogesterone. Insulin resistance appears to be improved. Blood pressure and bodyweight are not generally affected to any clinically important extent. Serum homocysteine levels were reported to decrease in postmenopausal women with high pretreatment levels. No data are available on the general tolerability profile of this regimen. However, the adverse events that most commonly led to discontinuation of treatment in clinical trials were typical of those associated with HRT, including vaginal bleeding headache, bloating and breast tenderness. Although the risk of breast cancer has not been specifically assessed for this regimen, it is unlikely to carry a greater risk than that of other HRT regimens. In summary available data indicate that treatment with continuous oral estradiol plus sequential dydrogesterone is effective in relieving climacteric symptoms and preserving BMD in postmenopausal women. The dydrogesterone component provides good endometrial protection and cycle control without negating the cardiovascular benefits of estradiol. Comparisons with other standard HRT regimens and long term data (including clinical end-points) are needed. In the meantime, this regimen can be regarded as an acceptable HRT option. 相似文献
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MM Faas WW Bakker PA Klok JF Baller GA Schuiling 《Canadian Metallurgical Quarterly》1997,77(4):767-771
The effect of 17-beta-oestradiol (OE2) upon the activity of the glomerular anti-thrombotic ecto-enzyme ADPase was studied in cyclic and ovariectomized (OVX) Wistar rats. On day 0 (i.e. at the time of ovariectomy or 11 days after ovariectomy) rats received OE2-releasing Silastic implants or empty implants and were sacrificed on day 3, 10 or 21. Cryostat kidney sections were histochemically stained for ecto-ADPase activity using enzyme-histochemistry and glomerular reaction product was quantitatively evaluated by computerized image analysis. Both the histological distribution of reaction product in each glomerulus, as reflected by the relative glomerular area covered with reaction product, as well as enzyme activity, as reflected by staining intensity of the reaction product, were scored. The results show significantly decreased histological distribution after OVX; OVX, however, did not change enzyme activity. It further appeared that OE2 (partly) prevented the decrease of histological distribution in OVX rats, while the enzyme activity was significantly increased by exogenous OE2. In cyclic rats, OE2 did not change histological distribution, although OE2 significantly increased enzyme activity in these rats. It is concluded that glomerular ecto-ADPase expression in the rat kidney is influenced by one or more ovarian factor(s), a very likely candidate being oestradiol. These results may thus point to a dual action of OE2 upon haemostasis: In addition to the known enhancement of procoagulatory plasma factors by OE2, also anti-aggregatory effects may be stimulated by OE2 as reflected by upregulation of vessel wall associated ecto-ADPase activity. 相似文献
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Clifford E. Shamblen 《Metallurgical and Materials Transactions B》1997,28(5):899-903
Normal liquid to solid partitioning of Cr during ingot solidification for the Ti-17 alloy can result in the formation of a
segregation anomaly called “β flecks.” These β flecks can exhibit a significantly lower β transus than the alloy; they may also present mechanical property issues. While the major thrust toward minimizing β flecks is through melt process control, this article addresses the capability of reducing the extent of Cr segregation using
a high-temperature β field homogenization heat treatment. The interdiffusion coefficients for Cr in β phase Ti-17 were determined and used in diffusion equations to calculate the rate of dissipation of the segregated regions.
Correlation is shown for the calculated, and critical experiment demonstrated, increase in the β fleck β transus temperature with the time and temperature of these homogenization heat treatments. 相似文献
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K Spencer 《Canadian Metallurgical Quarterly》1976,13(4):438-448
Previous studies of continuous flow kinetics have described an "AutoAnalyzer" peak in terms of two time constants, lag constant "a" and exponential constant "b". Further investigations described here define some of the factors which affect these constants and hence peak shape and analytical performance. This communication outlines the application of this information to the development of an automated method for the determination of serum calcium, having a carry-over of less than 1% and an analytical rate greater than 100/hour. The instaneous colour reaction, simple hydraulics, removal of the dialysis step, and the use of an integral debubbling flow cell have enabled small kinetic constants to be achieved. Over a period of three months' routine use between-batch co-efficient of variation (C.V.) was 1.4%. 相似文献
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We have prepared 3-methoxymethyl-16 beta, 17 beta-epiestriol-O-cyclic sulfone (1c) and used it as a substrate for the production of F-18 16 alpha-fluoroestradiol, via nucleophilic fluorination with fluoride ion. The compound is straightforward to make from the commercially available epiestriol and is a stable crystalline compound that can be stored for at least a year at room temperature. Reaction with fluorine-18 fluoride provides excellent yields; typically > 90% incorporation of the fluoride is achieved. Partial purification of the labeled product may be accomplished at this stage. Hydrolysis of the methoxymethyl protecting group and ring-opened sulfate occurs rapidly in ethanolic acid solution. In the presence of water the hydrolysis requires more vigorous conditions and additional time but still proceeds to completion. Labeled fluoroestradiol is isolated at the end of a 1-2 h synthesis, depending on the hydrolysis method of 30-45% chemical (decay corrected) yield with respect to fluoride, with a specific activity > 1 Ci per micromole. 相似文献
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M Prouse 《Canadian Metallurgical Quarterly》1995,91(49):40-41
The handover of information between shifts is often a time-consuming activity. It can involve all available staff from both shifts being absent from the ward for a substantial period of time. At a time when cost-effectiveness is an issue, many managers are looking at the value for money that the handover period provides. This paper describes an attempt by Trinity Hospic in Clapham actively to examine the cost in time and money that handover incurred, together with an examination of the quality of staff-to-staff reporting using tape-recorded handovers. 相似文献
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C Mottet CC Sieber A Nauer J Drewe R Fried F Larsen C Beglinger 《Canadian Metallurgical Quarterly》1998,27(4):920-925
Fas is expressed in various cells and transduces the cell death signal. p21 is a mediator of p53-dependent G1 arrest associated with deoxyribonucleic acid (DNA) damage. The upregulation of p53 and p21 associated with DNA damage in idiopathic pulmonary fibrosis has been described previously. In this study, p53, p21, and Fas expression and DNA damage were examined in interstitial pneumonia associated with collagen vascular diseases (CVD-IP). DNA damage was assessed by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick end-labelling (TUNEL) and p53, p21 and Fas proteins were detected by immunohistochemistry in 13 cases of CVD-IP, 13 of sarcoidosis, seven of hypersensitivity pneumonitis (HP) and eight control patients with normal lung parenchyma. TUNEL-positive signals were found in bronchiolar or alveolar epithelial cells in 11 of 13 (85%) specimens of CVD-IP, but not in sarcoidosis, HP or controls, except for a case of chronic HP with pulmonary fibrosis. p53, p21 and Fas were detected in bronchiolar or alveolar epithelial cells in nine (69%), 10 (77%) and 12 (92%) of 13 specimens of CVD-IP, respectively, but not in sarcoidosis, HP or controls, except for a case of chronic HP. These results suggest that the upregulation of p53, p21 and Fas in bronchiolar and alveolar epithelial cells associated with deoxyribonucleic acid damage may participate in the process of pulmonary fibrosis in interstitial pneumonia associated with collagen vascular diseases and chronic hypersensitivity pneumonitis. 相似文献
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N Sattar IA Greer A Rumley G Stewart J Shepherd CJ Packard GD Lowe 《Canadian Metallurgical Quarterly》1999,81(1):71-75
BACKGROUND: Chronic leukemia is a disease characterized by the malignant proliferation of immunologically incompetent lymphocytes. The knowledge of open heart surgery in patients with this disorder is limited. METHODS: Twelve patients with chronic lymphocytic leukemia underwent open heart surgery (nine coronary artery bypass grafting (CABG), two aortic valve replacement (AVR), one CABG and AVR) from September 1991 to September 1996. There were nine males and three females with a mean age of 68 years (41-81 years). Staging was assigned according to the Rai Classification. There were seven Stage 0, two Stage I, zero Stage II, one Stage III and two Stage IV patients. Cardiopulmonary bypass (CPB) was performed using standard techniques of cannulation, moderate hypothermia and antegrade/retrograde cardioplegia. RESULTS: Hospital mortality occurred in two (17%) patients. Both patients died of sepsis. Hospital morbidity occurred in seven (58%) patients. The most common complications were infections. Five patients were found to have other malignancies (basal cell, laryngeal, prostate, bladder and breast cancers). Transfusion of blood products was required in eight (67%) patients. The average length of stay was 15 days (7-50 days). Follow-up was complete. Late mortality occurred in four patients at a mean of 7 months (1-18 months). All deaths were non-cardiac related (ruptured AAA, kidney failure, respiratory failure and sepsis). Six patients remain alive at a mean of 25 months (1-48 months). CONCLUSION: Hospital mortality and morbidity in patients with chronic lymphocytic leukemia undergoing open heart surgery are high. Infection is the leading cause of hospital death, as well as the most common complication. The majority of patients receive blood products during the course of their hospitalization. Late mortality is high and non-cardiac related. Based on these findings, a re-definition of the aims, goals and expectations of open heart surgery in patients with chronic leukemia is necessary. Suggestions in management are presented. 相似文献
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RC Li PK Narang RC Lewis NZ Hatfield DT Rossi DC Colborn 《Canadian Metallurgical Quarterly》1993,33(4):373-380
A 100- to 3200-mg dose range of FCE 22,178 was studied in this phase I single-dose escalation safety/kinetics study. After oral administration, a rapid drug absorptive phase and a biexponential disposition profile were observed. Mean estimates of the terminal elimination half-life of FCE 22,178, over the doses studied, ranged from 7.6 to 14.4 hours. A disproportionate increase in both maximum peak plasma concentration (Cmax) and area under the curve (AUC0-infinity) was noticed for doses higher than 400 mg. Mean estimates of systemic clearance (CLs/F) over the 100- to 400-mg doses were 0.053 to 0.064 L/hour/kg, and were significantly higher for the three higher dose levels. This nonlinearity appears to be related to the changes in oral bioavailability. Estimates of distribution volume (Vd, lambda z/F) for FCE 22,178 increased from 0.75 L/kg at the 100-mg dose to 3.00 L/kg at the 3200-mg dose, and renal clearance (CLr) also increased with dose. Both observations may be related to an increase in free fraction of FCE 22,178 at higher doses. Urinary excretion of unchanged drug averaged < 10% for all dose levels. The urinary excretion of the glucuronide metabolite (M1) averaged 41 to 70% for doses up to 400 mg, but diminished to 13% at the 3200-mg dose. The disposition of M1 appeared to be formation-rate limited. In addition, the ratio of the formation to the disposition clearance for M1 was relatively stable and apparently dose independent. No drug-related adverse experiences were observed over the studied dose range after single doses at FCE 22,178. 相似文献