共查询到20条相似文献,搜索用时 15 毫秒
1.
M Inagaki K Yuasa E Nakayama T Kawazu T Chikui S Kanda H Yoshikawa S Nakamura M Shinohara 《Canadian Metallurgical Quarterly》1998,85(5):613-618
The Health Physics Department of the Korea Atomic Energy Research Institute and the Human Monitoring Laboratory have collaborated to compare the LLNL and JAERI torso phantoms. The counting efficiencies of the phantoms at 17.7 keV, 59.5 keV, 121.8 keV, and 344 keV were measured with KAERI's germanium lung counting system. The data were made comparable by converting the chest wall thicknesses and adipose mass fractions of the phantoms to muscle equivalent chest wall thicknesses. The counting efficiencies of the two phantoms are within 12% to 17% of each other at 17.7 keV, 15% to 22% at 59.5 keV, 10% to 15% at 121.8 keV, and 7% to 10% at 344 keV. This joint study has shown that the LLNL and JAERI phantom are essentially equivalent for the purposes of calibrating a lung counting system that consists of two ACTII germanium detectors. 相似文献
2.
M Bourgeois 《Canadian Metallurgical Quarterly》1995,72(7):30-34
It was shown that a single intraperitoneal administration of Bacillus intermedius RNAse to rats stimulated the activity of lysozyme and blood serum complement. A single intraperitoneal administration of pancreatic RNAse, Bacillus intermedius RNAse and its derivative selectively inactivated by the histidine active centre stimulated the metabolic activation of neutrophils as was shown by their ability to reduce tetrazolium nitroblue to diphormazone. The efficiency of the neutrophil stimulation by the RNAses was comparable with that of the microbial vaccine and did not depend on the catalytic activity of the RNAses. 相似文献
3.
CG Diederichs WG Engelke B Richter KP Hermann JW Oestmann 《Canadian Metallurgical Quarterly》1996,17(9):1758-1760
We evaluated the feasibility of performing preoperative spiral CT of the maxilla and mandible with a radiation dose similar to that used for conventional panoramic radiography. The skin entrance doses of radiation used for spiral CT (collimation, 1 mm; pitch, 2; tube voltage, 80 kV; tube current, 40 mA) and for panoramic radiography (75 kV, 8 mA, 15 seconds) were measured in one patient by using thermoluminescent dosimeter chips. Results were 0.56 +/- 0.06 mGy for CT and 0.59 +/- 0.04 mGy for radiography. Image quality was adequate for preoperative implant planning. Spiral CT of the mandible and maxilla may therefore be feasible with a radiation dose of similar magnitude as that used for conventional panoramic radiography. 相似文献
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STUDY DESIGN: A reliability study was performed using repeated random measurements involving three observers, 26 subjects and three instruments. OBJECTIVES: To determine the most reliable, cost-effective, noninvasive, and clinically feasible method of measuring spinal kyphosis. SUMMARY OF BACKGROUND DATA: The most clinically useful, noninvasive and reliable method of measuring postural deformity in spinal osteoporosis (kyphosis) remains unqualified. Despite traditional use of costly, invasive roentgenographs for the evaluation of spinal kyphosis, the reliability of this method remains questionable. METHODS: Twenty-six postmenopausal women with known bone mineral density and a diagnosis of osteoporosis were recruited from the Osteoporosis Program at Women's College Hospital, Toronto, Canada. Non-invasive measurements of thoracic kyphosis were obtained by three trained examiners using the DeBrunner's kyphometer and the flexicurve ruler. The intrarater and interrater reliability of and between each method was compared, using roentgenographic films obtained in the sagittal plane. Spinal posture was classified according to the method of Itoi (1990). Statistical computations were performed using SAS statistical software. RESULTS: Consistent measurements were obtained with the DeBrunner's kyphometer and the flexicurve ruler by each observer, according to the results of critical two-way analysis of variance (Intraclass Correlation Coefficient 2, 1). Measurements in two subgroups, healthy backs (n = 11) and rounded backs (n = 13), showed consistent use of each noninvasive instrument with some examiner preference for specific tools. There was marginally better intrarater and interrater reliability using the DeBrunner's kyphometer compared with that obtained with the flexicurve ruler. Two-way analysis of variance (Intraclass Correlation Coefficient 2, 1) of collapsed data showed no significant difference in the reliability of the kyphometer, flexicurve ruler, or roentgenographs in the measurement of thoracic kyphosis. CONCLUSIONS: The flexicurve ruler and DeBrunner's kyphometer had the closest agreement in the measurement of spinal kyphosis. The kyphometer demonstrated the least variation in intrarater and interrater reliability when compared with the flexicurve ruler and roentgenographs. The flexicurve ruler permits qualitative assessment of posture, however, and is the most cost-effective instrument. The results of this study challenge the traditional belief that roentgenographic analysis is the best method for evaluating spinal kyphosis. The DeBrunner's kyphometer and flexible ruler may represent viable, cost-effective and noninvasive alternatives to roentgenographic evaluation of spinal kyphosis. 相似文献
6.
R Lisker MA López S Jasqui S Ponce De León Rosales R Correa-Rotter S Sánchez OM Mutchinick 《Canadian Metallurgical Quarterly》2003,75(3):399-403
It has been reported that Vitamin D receptor polymorphisms are associated with osteoporosis, particularly those demonstrated by the BsmI and FokI restriction enzymes. Herein we report the results of a case-control study performed in postmenopausal Mexican women. We studied 65 osteoporotic women (< or = -2.5 SD bone mineral density [BMD] of young normal females) and 57 controls (over 90% > or = -1.5 SD BMD of young normal females. Restriction enzymes BsmI and FokI were used to identify polymorphisms. Odds ratios and their 95% confidence intervals were calculated, and analysis was performed controlling for age as a covariate. The BsmI genotypes revealed a higher frequency of the bb genotype in cases than in controls, contradicting much of the literature that suggests this genotype protects females against osteoporosis. Regarding the FokI genotypes, we were unable to confirm that the FF genotype has a protective effect against osteoporosis. The inconsistencies found in the literature and the results obtained in the present work suggest to us that other genetic and nongenetic factors are involved in the occurrence of osteoporosis, confounding the results of the possible association of osteoporosis and VDR polymorphisms. 相似文献
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Verbal working memory involves two major components: a phonological store that holds auditory-verbal information very briefly and an articulatory rehearsal process that allows that information to be refreshed and thus held longer in short-term memory (A. Baddeley, 1996, 2000; A. Baddeley & G. Hitch, 1974). In the current study, the authors tested two groups of patients who were chosen on the basis of their relatively focal lesions in the inferior parietal (IP) cortex or inferior frontal (IF) cortex. Patients were tested on a series of tasks that have been previously shown to tap phonological storage (span, auditory rhyming, and repetition) and articulatory rehearsal (visual rhyming and a 2-back task). As predicted, IP patients were disproportionately impaired on the span, rhyming, and repetition tasks and thus demonstrated a phonological storage deficit. IF patients, however, did not show impairment on these storage tasks but did exhibit impairment on the visual rhyming task, which requires articulatory rehearsal. These findings lend further support to the working memory model and provide evidence of the roles of IP and IF cortex in separable working memory processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
AB Kovács 《Canadian Metallurgical Quarterly》1994,41(1-2):86-87
The efficacy of ipriflavone was investigated in a 1-year double-blind, placebo-controlled, parallel group clinical trial. Ninety-one postmenopausal women completed the study, 41 received ipriflavone and 50 placebo treatment. After six months the bone mineral density of the L2-L4 vertebral region increased in the ipriflavone-treated group (0.015 g/cm2), whereas it decreased in the placebo-treated group. The differences between the treatment groups were statistically significant. Our results support the efficacy of ipriflavone in the treatment of postmenopausal osteoporosis. Since the positive effect was more pronounced after 6 months, the possibility of an intermittent ipriflavone treatment might be taken into consideration in the future. 相似文献
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In 47 women with postmenopausal osteoporosis, pretreatment studies by microradiography, radioimmunoassay and other methods showed increased bone resorption, normal bone formation, and decreased serum immunoreactive parathyroid hormone (PTH). In patients treated with a physiologic replacement dose of estrogen, bone resorption decreased to normal and PTH increased after short-term therapy; bone formation decreased to very low levels after long-term therapy. These data indicate that, in most patients, both an intrinsic abnormality of bone cell function and a disruption of the normal regulation of bone turnover by PTH and sex hormones, as a result of the menopause, are important in the pathogenesis of osteoporosis. 相似文献
10.
E Lundgren E Szabo S Ljunghall R Bergstr?m L Holmberg J Rastad 《Canadian Metallurgical Quarterly》1998,317(7162):848-851
OBJECTIVE: To analyse sick leave in women at risk of primary hyperparathyroidism before its diagnosis. DESIGN: Case-control study nested within a screened cohort of postmenopausal women. Cases were women with hyperparathyroidism without prior knowledge of their disease and no traditional symptoms or complications. Controls were women from the screened population without hyperparathyroidism. SETTING: Population based screening within a Swedish community. SUBJECT: 48 case-control pairs of women aged 55-70 years. MAIN OUTCOME MEASURE: Sick leave during the 5 years before diagnosis. RESULTS: Total duration of sickness benefits was longer in the cases than controls, and this discrepancy included sick leave on full time or half time and for periods of longer than a week. Cases had an increased risk of sick leave more than half of the investigated time compared with controls (odds ratio 12). Doctors' certificates showed that the overrepresented sick leave in the cases related mainly to cardiovascular diseases. CONCLUSION: Asymptomatic mild primary hyperparathyroidism in postmenopausal women is accompanied by a previously unrecognised morbidity, which has consequences for clinical management of the disorder and its impact on the health economy. 相似文献
11.
SS Rodionova 《Canadian Metallurgical Quarterly》1995,67(10):43-45
A 1-year administration of osteoquine (7-isopropoxyisoflavon) to 20 patients with postmenopausal and senile systemic osteoporosis has shown a pronounced analgetic effect of this drug, its ability to stop the loss of and in some instances to increase bone mass, to stimulate osteogenesis. 相似文献
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A substantial portion of smokers are peri- or postmenopausal women. Cigarette smoking and menopause have overlapping negative health consequences and may act synergistically to contribute to worse health outcomes in this population. Little is known about issues specific to peri- and postmenopausal women attempting to quit smoking; however, it can be hypothesized that they face unique challenges in quitting smoking. Particularly, negative affect and vasomotor menopausal symptoms may make smoking cessation particularly challenging in this group of women. Peri- and postmenopausal women are also more prone to weight gain following smoking cessation, and concerns about postcessation weight gain may contribute to reduced motivation to quit smoking or to relapse to smoking. Recent evidence suggests that estrogen level may be positively associated with nicotine reward, which may aid in the smoking cessation efforts of postmenopausal women while possibly contributing to worse outcomes in perimenopausal women. Unfortunately, no known studies have compared premenopausal women with peri- or postmenopausal women on smoking cessation outcome variables. Studies in postmenopausal women indicate that hormone therapy (HT) use does not affect nicotine withdrawal, smoking cessation outcomes, or weight gain following smoking cessation; however, a lack of randomized trials limits the strength of these conclusions. Evidence of the effects of HT on mood following smoking cessation is conflicting. Further research is needed to identify the unique factors influencing smoking cessation in peri- and postmenopausal women and to develop and test interventions that target these variables in a way that improves cessation rates among this population. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
13.
SJ Wimalawansa 《Canadian Metallurgical Quarterly》1998,104(3):219-226
The aim of this study was to investigate the extent of natural intrinsic fluorescence in carious human dentine and any correspondence of such autofluorescence (AF) to the mineral distribution within the lesion. Two investigative techniques were used, both employing the same sample set and fields in diamond-polished block surfaces of polymethylmethacrylate-embedded carious teeth. AF at emission wavelengths >515 nm, excited by 488-nm laser light, was assessed using a confocal laser scanning optical microscope (CLSM), the recordings made under standard operating conditions. The relative mineral content was assessed using digital backscattered scanning electron microscopy (20 kV BSE-SEM). The AF intensity correlated with the level of demineralisation as seen by BSE, but the depth of the lesion as seen by CLSM was significantly greater implying that the AF is not directly related to the mineral component. 相似文献
14.
Normal bone mass is one of the principal factors in the prevention of osteoporosis for women in advanced age. Therefore, it is necessary to have efficacious serum and urinary markers available to screen the bone development and the bone resorption. Even if we are also far from identifying an ideal marker, the measurement of some substances such as pyridinoline (Pyr) and deoxypyridinoline (D-Pyr) seems to be a first progress for efficacious and rather simple techniques. 相似文献
15.
LJ Melton EJ Atkinson S Khosla WM O''Fallon BL Riggs 《Canadian Metallurgical Quarterly》1999,24(1):49-55
Recent reports have indicated that large-dose opiate anesthesia can increase neuronal injury in rats subjected to forebrain ischemia. However, most episodes of cerebral ischemia in the operating room setting are focal in nature, and the influence of large-dose opioid administration on the tolerance of the brain to focal cerebral ischemia has not been studied. Accordingly, we undertook the present study to evaluate the effect of fentanyl administration on outcome after focal cerebral ischemia. Three groups of fasted Wistar-Kyoto rats (awake, fentanyl, and isoflurane groups; n = 20 per group) were anesthetized with isoflurane (2.5% end-tidal). Pericranial temperature was servocontrolled at 37.0 degrees C. After surgical preparation fentanyl 50 microg/kg was administered IV over 10 min in the fentanyl group. Thereafter, an infusion was established at a rate of 50 microg x kg(-1) x h(-1). The end-tidal concentration of isoflurane was then reduced to 1.1%, one minimum alveolar anesthetic concentration (1 MAC) in all groups. Occlusion of the middle cerebral artery was achieved by advancing a 0.25-mm filament into the anterior cerebral artery via the common carotid artery. In the fentanyl and awake groups, isoflurane administration was then discontinued. In the isoflurane group, isoflurane anesthesia was maintained at 1.0 MAC. After 90 min of focal ischemia, the filament was removed, and the animals were allowed to recover. Seven days later, the volume of cerebral infarction in the animals was determined by image analysis of hematoxylin and eosin-stained coronal brain sections. There was no difference in the infarct volume between the fentanyl and awake groups. The infarct volume was the least in the isoflurane group. The results confirm the ability of isoflurane to reduce brain injury caused by focal cerebral ischemia. Fentanyl neither increased nor decreased brain injury compared with the awake unanesthetized state. IMPLICATIONS: Fentanyl is commonly used in surgical procedures in which there is a substantial risk of focal cerebral ischemia. Fentanyl did not affect cerebral injury produced by focal ischemia in the rat. The data suggest that, in doses that produce respiratory depression and muscle rigidity, fentanyl does not reduce the tolerance of the brain to a focal ischemic insult. 相似文献
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G Demircin A Oner N Ecin M Bülbül I Somuncu H Tunali 《Canadian Metallurgical Quarterly》1998,40(5):461-465
OBJECTIVE: To calculate the expected prevalence of resistant HIV mutants before antiviral therapy. DESIGN: HIV replication generates virus mutants. The prevalence of these mutants is determined by mutation and selection/fitness. Some mutations will confer drug resistance and it is crucial for the success of antiviral drug therapy to determine whether these resistant viruses are present before the initiation of therapy. METHODS: A quasispecies equation was used to calculate the expected frequency of drug-resistant virus prior to therapy. RESULTS AND CONCLUSIONS: We show how the pretreatment frequency of resistant virus depends on the number of point mutations between wild-type and mutant virus, the selective disadvantage of the resistant mutant and the intermediate mutants, and the mutation rate. 相似文献
18.
JL Moyano Calvo A Ortiz Gamiz JA Romero Díaz A Martínez Moran JJ Zerpa Railey J Casti?eiras Fernandez 《Canadian Metallurgical Quarterly》1998,22(8):655-660
INTRODUCTION AND OBJECTIVES: The minimum value of dP/dT is a parameter of diastolic function that can be estimated noninvasively by analyzing the profile of velocity of the mitral regurgitant jet, recorded by continuous-wave Doppler. This estimation requires a complex analysis of the curves that impedes its practical use. Our objective was to validate a simplified method to estimate noninvasively the value of dP/dTmin when mitral regurgitation exists. We calculated the pendient of the profile of velocity of the curve of mitral regurgitation during its deceleration, between 3 and 1.5 m/s, an interval that defines a difference in pressure using the formula delta p = (4v2(1) - 4v2(2)). We divided this interval by the time needed by the jet to decelerate from 3 to 1.5 m/s, obtaining the rate of pressure decay, in mmHg/s. METHODS: We provoked mitral regurgitation in five pigs and registered dP/dT and the curve velocity of mitral regurgitation simultaneously, by micromanometer-tipped catheter and continuous-wave Doppler, respectively. The rate of pressure decay was calculated on the mitral regurgitation curve. RESULTS: We obtained 29 simultaneous registers. The coefficient for the correlationship between dP/dT and the rate of pressure decay was with an r value of 0.62 (p < 0.0001). The rate of pressure decay underestimated systematically the value of dP/dT. Intra and interobserver variability of TDP was 9 and 11%, respectively. CONCLUSIONS: This study validates a simplified method to estimate dP/dT noninvasively, with acceptable correlation with invasive measurements and adequate reproducibility. 相似文献
19.
G Liu M Peacock O Eilam G Dorulla E Braunstein CC Johnston 《Canadian Metallurgical Quarterly》1997,7(6):564-569
To select for bacterial strains with enhanced phenotypes, random fragments of a whole genome, or a defined region of the genome, are cloned in a nonreplicating vector. The resulting plasmids are integrated by recombination into the homologous DNA region of the original strain. Integration gives rise to a nontandem direct duplication of the corresponding DNA region separated by the vector moiety of the plasmid. Recombination between the direct repeats leads to tandem duplication and further amplification of the entire integrated DNA, including the vector. Bacteria harboring the amplified DNA are selected by increasing the dosage of an antibiotic corresponding to a resistance marker of the integrated vector. Pooled strains carrying amplifications are then challenged with a selective pressure for the desired phenotype. After repeated selection cycles, the most fit strains are isolated. We used this process, which we called random DNA amplification, to select Rhizobium strains with increased competitiveness for nodule formation. Derivatives containing randomly amplified DNA regions of the symbiotic plasmid of Rhizobium tropici CFN299 strain were generated. Pools of amplified strains were inoculated onto various tropical legumes. After several cycles of selection through plants, amplified derivatives showing an increased competitiveness for nodule formation with the leguminous plant Macroptilium atropurpureum were obtained. 相似文献
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F Blanckaert B Cortet P Coquerelle RM Flipo B Duquesnoy X Marchandise B Delcambre 《Canadian Metallurgical Quarterly》1997,64(5):305-313
Inflammatory cytokines have been described to play a critical role in the orientation and amplification of the IgA immune response. In this study, we show that the intranasal administration of a Bordetella pertussis strain expressing the protective antigen glutathione-S-transferase of Schistosoma mansoni (Sm28GST) induced an inflammatory response in the lungs of mice, characterized by the production of inflammatory cytokines, such as Tumor Necrosis Factor alpha, Interleukin-6 and Transforming-Growth Factor beta. The production and the secretion of these cytokines in lung tissues were early and transient. Their presence was observed only during the first week after administration despite the persistence of the bacteria for 1 month. Two weeks after inoculation, Interleukin-10 secretion was detected in the lungs, which could explain the decrease in the production of inflammatory cytokines. These inflammation-regulating cytokines, induced in the lungs by the presence of the bacterial vector, could be part of the process generating the local immune response, in particular the anti-Sm28GST IgA response. 相似文献