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101.
The contributions of the relative radius, relative wall thickness, incremental strain, incremental elastic modulus, and medial scleroprotein content to the static elastic properties of the rat aortic wall have been examined in three groups of rats. Controls, rats made hypertensive at four weeks of age, and rats whose blood pressure was lowered after 6 weeks hypertension, were studied. The results show evidence of adaptive changes in the aorta of hypertensive animals, and that irreversible alterations in the mechanical properties of the wall may be induced by a brief period of hypertension. A direct relationship between aortic medial scleroprotein content and the elastic properties of the wall is demonstrated. 相似文献
102.
A transplacentally induced lung tumor of strain C3Hf mice grows progressively when transplanted to (C3Hf X A)F1 hybrid mice but not when transplanted to C3Hf recipients. Progressive tumor growth occurs in [(C3Hf X A)F1 X C3Hf] backcross mice inheriting the H-2a haplotype from the F1 parent. Furthermore, radioresistant immunity to the lung tumor can be induced in C3Hf mice by immunization with normal tissue of B10.A and B10.A(2R) but not of B10 or B10.A(5R) strain mice. 相似文献
104.
105.
Bone repair by regeneration as we know it continues to undergo changes, with advances approaching that may change our treatment of patients with craniofacial deformities and skeletal defects. Perhaps by the turn of the century, patients born with asymmetric deformities due to lack of growth will be treated early in life by skeletal stretching, and then later in life by skeletal distraction that is followed by use of accelerating factors to assist the healing processes. All of these available modalities are part of the regeneration of new bone formation. The future of such changes is very interesting, and our ability to help our patients will be maximized. We may even look back 25 years from now at bone grafting and find it to be obsolete and crude. It is hoped that with the new modalities being developed, we will not deviate from the use of a bone grafting procedure, which is the workhorse of the craniofacial surgeon. Bone grafting is used by all surgeons working on the craniofacial skeleton despite the problems of unpredictability of healing and an inability to calculate what percentage of the original graft will survive. The transplantation issue will be solved. The problems with donor site morbidity will continue. The use of inorganic bone substitutes will continue to have its limitation, particularly in type II wounds, which we as plastic surgeons see in the craniofacial region. As we redefine our approach to skeletal repair, we may look back and find solutions to some of the major problems we have had. The rapid stretch of soft tissue after facial advancement or structural alteration that is accompanied by a relapse due to the elastic recoil of the soft tissue could be eliminated by gradual distraction. The bone will undergo better functional adaptation when it has a gradual change in structure based on adjustment and molding in a gradual fashion. The problem of donor site morbidity and a prediction formula for bone could be resolved with new bone formation in situ by mineralization of the area under repair. Bone healing enhancers are here to stay and their clinical application will produce a far-reaching better final outcome (Fig. 11). 相似文献
106.
107.
Y Yang SE Raper JA Cohn JF Engelhardt JM Wilson 《Canadian Metallurgical Quarterly》1993,90(10):4601-4605
Cystic fibrosis (CF) is an inherited disease of epithelial cell ion transport that is associated with pathology in multiple organ systems, including lung, pancreas, and liver. As treatment of the pulmonary manifestations of CF has improved, management of CF liver disease has become increasingly important in adult patients. This report describes an approach for treating CF liver disease by somatic gene transfer. In situ hybridization and immunocytochemistry analysis of rat liver sections indicated that the endogenous CFTR (cystic fibrosis transmembrane conductance regulator) gene is primarily expressed in the intrahepatic biliary epithelial cells. To specifically target recombinant genes to the biliary epithelium in vivo, recombinant adenoviruses expressing lacZ or human CFTR were infused retrograde into the biliary tract through the common bile duct. Conditions were established for achieving recombinant gene expression in virtually all cells of the intrahepatic bile ducts in vivo. Expression persisted in the smaller bile ducts for the duration of the experiment, which was 21 days. These studies suggest that it may be feasible to prevent CF liver disease by genetically reconstituting CFTR expression in the biliary tract, using an approach that is clinically feasible. 相似文献
108.
SE King D Schottenfeld 《Canadian Metallurgical Quarterly》1996,10(4):453-62; discussion 462, 464, 470-2
Breast cancer incidence rates in the United States rose by 24% between 1973 and 1991. Mortality during this period, however, remained stable. Both the 5-year relative survival rate and the rates of in situ and stage I breast cancers have been increasing, while the incidence of later-stage cancers has been decreasing. Increased mammography screening may explain the documented jump in breast cancer incidence rates during the mid-1980s. Differences in the distribution of breast cancer risk factors may account, in part, for the temporal trends in breast cancer incidence. In particular, breast cancer risk factors may vary by birth cohort, including age at menarche, age at first birth, physical activity, obesity, diet, alcohol intake, estrogen therapy, and exposure to environmental organochlorines. After decades of epidemiologic research, a preventive approach to breast cancer that focuses on the physiologic effects of the sex steroid hormones, and their potential interactions with family history, is being carefully formulated. 相似文献
109.
PG Vinicoff E Gutschik SE Hansen A Karle K Rieneck 《Canadian Metallurgical Quarterly》1998,160(41):5931-5934
Since February 1987 percutaneous CT-guided spine biopsy was performed in 18 patients with spondylodiscitis at the X-ray Department of Bispebjerg Hospital. Eleven cases were spontaneous and seven followed spinal surgery. The infection was located in five cases in the thoracic spine and in 13 cases in the lumbar spine. Only one biopsy was performed during general anaesthesia, the rest under local anaesthesia. No complications were observed. The bioptic material was cultivated immediately beside the patient and incubated for 14 days. The infective organism was isolated in 12 cases (67%). Thus, material obtained through a fine needle was satisfactory for microbiological investigation. A biopsy is crucial for establishing a microbiological diagnosis and thereby enabling prompt adequate treatment. 相似文献
110.
Human gene for physical performance 总被引:2,自引:0,他引:2