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C Kotwall D Covington P Churchill C Brinker D Weintritt JG Maxwell 《Canadian Metallurgical Quarterly》1998,176(6):510-514
Physical exercise is recommended for the prevention and treatment of osteoporosis. However, its exact role and effectiveness in adulthood is unclear. While vigorous exercise of long duration enhances bone density, few adult individuals comply with such training programs. The present study evaluates the influence of nonphysiological mechanical stimulation, in the form of low intensity vibration (frequency: 50 Hz, acceleration: 2 g, 30 min/day for 5 days/week), on the prevention of bone loss in an animal model of postmenopausal osteoporosis. In the ovariectomised groups of rats a statistically significant (p < 0.05) decrease of bone density (femur and tibia) was recorded at 5 weeks postovariectomy. This effect was maintained for the 12 week duration of the study. Vibration prevented early bone loss after ovariectomy. Vibrated ovariectomised rats showed statistically significantly higher (p < 0.05) BMD values compared to those of their ovariectomised controls at 5 weeks. Vibration did not influence the bone density of the SHAM-operated rats. Although vibration increased ultimate strength (fracture load of the rat femur) in the ovariectomised rats, this finding was not statistically significant. Our data indicate that this method of safe and easily applicable vibration, in the form of a vibrating platform, is effective in preventing early postovariectomy bone loss in an animal model. 相似文献
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P Italiano A Ciaccia P Malacarne P Piffanelli A Della Piccola 《Canadian Metallurgical Quarterly》1976,67(24):1557-1560
The possibility that chromosome alterations take place in personnel exposed to electromagnetic radiation in radar centres has been studied. The study was carried out "blind" on short-term cultures of peripheral blood, some 450 metaphases being analysed for each case. No aberrations were found in either radar operators or controls and there was no statistically significant difference between them. 相似文献
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The medical specialist training at all levels (medical orderly, doctor's assistant, general practitioner, doctors) should be based on the medical care standards. Preliminary studies in the field of military medicine standards have demonstrated that the medical service of the Armed Forces of Russia needs medical resources' standards, structure and organization standards, technology standards. Military medical service resources' standards should reflect the requisitions for: all medical specialists' qualification, equipment and material for medical set-ups, field medical systems, drugs, etc. Standards for structures and organization should include requisitions for: command and control systems in military formations' and task forces' medical services and their information support; health-care and evacuation functions, sanitary control and anti-epidemic measures and personnel health protection. Technology standards development could improve and regulate the health care procedures in the process of evacuation. Standards' development will help to solve the problem of the data-base for the military medicine education system and medical research. 相似文献
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Donor CD4+ and CD8+ T cells mediate graft-vs.-leukemia (GVL) responses in the allogeneic bone marrow transplantation (alloBMT) setting. To evaluate the role of functional T cell subsets in the mediation of GVL, alloreactive donor CD4+ (Th1/Th2) and CD8+ (Tc1/Tc2) T cells of defined cytokine phenotype were generated by in vitro culture. A leukemia/transplantation model (B6 into B6C3F1; 1050 cGy host irradiation) was established using the bcr/abl-transfected myeloid leukemia line, 32Dp210 (P210; H-2k). Leukemia control mice (1X10(4) P210 cells per recipient) died at day 12.0 post-BMT. Recipients of the CD4+, Th1-type or CD8+, Tc1-type populations were conferred a survival advantage (death at 20.7 and 23.5 days post-BMT, respectively). In contrast, the CD4+, Th2-type population did not mediate GVL (death at 12.3 days). Furthermore, cell mixing experiments demonstrated that the Th2 subset abrogated both Th1- and Tc1-mediated GVL. The CD8+, Tc2 population, which secreted type II cytokines and lysed the P210 leukemia target in vitro, mediated GVL in some experiments; interestingly, the magnitude of Tc2-mediated GVL was inversely related to the level of interleukin-10 (IL-10) secreted in vitro by the Tc2 population. These studies therefore indicate that alloreactive T cells of type I phenotype maximally generate GVL, and that type I/type II interactions are an important consideration for allogeneic transplantation in the setting of leukemic hosts. 相似文献
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Investigated (a) acceptance by US Navy technical personnel of a proposed change-advocate role in which the change advocate was selected from and operated within the technical team to facilitate use of a new hardware system, (b) important characteristics for a change advocate in the shipboard setting, (c) whether some technical personnel possessed those characteristics, and (d) whether responses could be generalized across ship types. 83 technicians and 9 officers from various ship types responded to a questionnaire requiring nominations for a change advocate, ratings of nominees and of the importance of 25 traits, and sociometric ratings. Results reveal that the change-advocate role was deemed inportant, qualified technicians desired the role, and consensus was obtained for important characteristics of the change advocate. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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R Engelbrecht HD Schmeetz G Laude HO Von Gaertner PL Reichertz 《Canadian Metallurgical Quarterly》1976,15(4):199-205
Fifteen-second exposure of rabbit kidneys to 2 MHz focused ultrasound with approximately 900 w/sq cm acoustic power consistently produced localized parenchymal destruction. Evolution of the lesions was followed histologically over a one-year period. The lesions were sharply delineated from outlying renal tissue and had a concentric multizonal structure. Resorption of the damaged tissue with scarring was completed in 6 to 12 months following intermediate phases characterized by cellular infiltration. The lesions are compared to other models of renal injury, particularly with respect to cellular infiltration. A combination of mechanical, thermal, and ischemic factors seem to be responsible for development of ultrasonic lesions. The sharply circumscribed nature and ultimate complete scarring of the lesions suggest the feasibility of ultrasound in achieving selective complete destruction of renal parenchyma. 相似文献
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Late rectal sequelae following definitive radiation therapy for carcinoma of the uterine cervix: a dosimetric analysis 总被引:1,自引:0,他引:1
JC Roeske AJ Mundt H Halpern P Sweeney H Sutton C Powers J Rotmensch S Waggoner RR Weichselbaum 《Canadian Metallurgical Quarterly》1997,37(2):351-358
OBJECTIVE: The structure of the collagen scar during healing of a myocardial infarction is a determinant of the function of the remodeled tissue. We hypothesize that the passive deformations of both scar and normal tissue are related to the underlying collagen uncoiling as the tissue stretches, and that the unloaded tortuosity of the collagen may be a determinant of tissue stiffness at low ventricular pressure. Hence collagen uncoiling and tissue strain were measured during passive loading in normal tissue, and in healing infarct tissue. METHODS: Left ventricles of rats were infarcted by ligation of the left anterior descending artery for 2 weeks. Surface strains were measured during passive inflation in the scar region in one set of excised hearts, and other arrested hearts were fixed at different ventricular pressures, after which collagen tortuosity was measured in the infarcted and normal tissue. RESULTS: Passive loading strains were smaller in the scar in both the fiber and cross-fiber directions. Tortuosity decreased with load in normal and infarcted tissue, with fibrils tending to straighten more in the scar tissue at higher pressures (1.056 +/- 0.009 vs. 1.024 +/- 0.009 at P = 20 mmHg) with similar tortuosities at zero pressure (1.110 +/- 0.012 vs. 1.098 +/- 0.019). The decrease in tortuosity with strain was greater for the infarcted tissue. CONCLUSIONS: The greater stiffness of infarcted tissue at low pressure is not due to 'straightened' collagen fibers, and there may be a different three-dimensional structure of infarct vs. normal coiled collagen fibers which can affect the material properties of these tissues. 相似文献
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We recorded clinical information over a 12-month period on consecutive consultations to the gastroenterology service of the Durham VA Medical Center. Of 902 consultations, 789 were prospectively collected. Eighty-five percent of the patients were between 40 and 70 years old. Seventy-five percent of the referrals were from the internal medicine service. The most frequent reasons for consultation were abdominal pain (19%), GI bleeding (active, 16%; occult, 9%), abnormal results of liver tests (18%), and request for a procedure (11%). Diseases of the liver (32%) and "peptic diseases" (30%) were the most common diagnoses. One or more procedures were done in 71% of consultations. When these data are compared with those of a practicing gastroenterologist, using an identical instrument, it is apparent that trainees' experience with structurally identifiable gastroenterologic disease and with a variety of procedures was similar in scope. There were, however, differences in that the physicians at the VA saw substantially fewer patients with so-called "functional" illness. If these data are applicable to other VA Medical Centers, then the training of physicians in gastroenterology at a VA Medical Center should probably be broadened. 相似文献
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BP Knight A Zivin J Souza R Goyal KC Man A Strickberger F Morady 《Canadian Metallurgical Quarterly》1998,105(4):275-280
A 54-year old woman was scheduled for thoracotomy for excision of a tumor of the left upper lobe. Reduced thyromental distance and thyroid enlargement were identified by the preoperative physical examination and inability to visualize the larynx was encountered during direct laryngoscopy. A 37-Fr left sided double lumen tube was inserted in trachea with great difficulty after three failed attempts. One lung anesthesia underwent uneventfully and postoperatively it was decided to exchange the double lumen tube to a single lumen tracheal tube. After the extubation, five failed attempts of reintubation were performed. A laryngeal mask airway (LMA) size 3 was passed easily achieving an airtight airway. The patient underwent an uneventful prolonged (105 min) weaning via the LMA which was left in place until the patient regained full consciousness. Peripheral oxygen saturation remained greater than 95% throughout the airway manipulation. LMA insertion is an easy non-invasive technique and should be considered whenever airway management proves difficult. 相似文献