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1.
The birth of the first cloned mammals, produced by the introduction of somatic cell nuclei into enucleated oocytes, was an impressive and surprising development. Although the ethical debate has been intense, the important scientific questions raised by this work have been inadequately discussed and are still unresolved. In this essay we address three questions about nuclear transplantation in the eggs of mice and domestic animals. First, why were the recent experiments on somatic cell cloning successful, when so many others have failed? Second, were these exceptional cases, or is somatic cloning now open to all? Third, what are the future possibilities for increasing the efficiency and wider applicability of the cloning process?  相似文献   

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We report herein the case of a patient in whom aneurysms of the bilateral deep femoral arteries (DFA) and multiple iliac aneurysms associated with severe aortic valve disease were successfully treated by a two-staged operation. The patient was a 74-year-old man who had dense calcification of the ascending aorta and aortic arch. Prior to aortic valve replacement (AVR), the aneurysms of the DFA and internal iliac arteries were resected. The terminal end of the abdominal aorta and bilateral common iliac arteries were then reconstructed with a Y graft to be used as a possible alternative arterial input route in place of the ascending aorta for extracorporeal circulation during the AVR. The inferior mesenteric artery (IMA) was well developed, and the external iliac arteries and their branches were preserved at aneurysmectomy. Postoperatively, there was no ischemia of the pelvic organs or the hip muscles. The AVR was subsequently performed 5 weeks after the first operation, and the patient was discharged after an uneventful postoperative course.  相似文献   

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A 76-year-old man was admitted with bilateral common iliac artery aneurysms found incidentally on computed tomography. Transfemoral digital subtraction arteriography demonstrated atherosclerotic plaques in the aorta with bilateral common iliac artery aneurysms and a coeliac axis aneurysm. The coeliac artery aneurysm was resected and an aortobifemoral bypass performed with reimplantation of the inferior mesenteric artery into the prosthesis. The patient was well when discharged 2 weeks after operation. The incidence, natural history and management of coeliac axis and iliac artery aneurysms are reviewed.  相似文献   

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We hypothesized that bilateral quisqualic acid lesions of the nucleus basalis magnocellularis (NBM) in rats would impair configural but not simple association learning. In experiment 1, rats were tested in a negative patterning operant discrimination where they were food-reinforced for responding to a light or a tone (L+, T+) but not for responding to the configural stimulus consisting of the light and tone presented simultaneously (LT-). Consistent with our hypothesis, NBM-lesioned rats showed a transient but significant impairment, responding normally to L+ and T+ but responding more often to LT-, in addition to responding more often during the inter-trial interval (ITI) than controls. In experiment 2, rats were tested in a simple operant discrimination where rats were food-reinforced for responding to a light (L+) but not for responding to a tone (T-). Although NBM-lesioned rats again responded normally to L+ as predicted, NBM-lesioned rats were transiently impaired, making more T- responses and more ITI responses than controls. Together, these results suggest that the NBM is involved in both configural and simple association learning but that this involvement is limited to learning to withhold responding to non-reinforced contextual or discrete stimuli. Finally, rats from experiment 2 underwent extinction trials, where results showed no difference between NBM-lesioned and control groups, suggesting that the NBM is not involved in the extinction of conditioned responding to previously reinforced stimuli.  相似文献   

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The purpose of this study was to compare the physiological responses of professional and elite road cyclists during an incremental cycle ergometer test. Twenty-five elite cyclists (EC; 23+/-1 yr) and 25 professional cyclists (PC; 25+/-2yr) performed a ramp protocol (increases of 25 W x min(-1)) during which the following parameters were measured: oxygen consumption (VO2), pulmonary ventilation (VE), ventilatory equivalents for oxygen and carbon dioxide (VE x VO2(-1) and VE x VCO2(-1), respectively), respiratory exchange ratio (RER), ventilatory thresholds 1 and 2 (VT1 and VT2, respectively), blood lactate, and electromyographic activity (EMG) of the vastus lateralis. Significant differences existed between the two groups mainly at submaximal intensities, since both VT1 and VT2 occurred at a higher exercise intensity (p<0.001) in PC than in EC (VT2: 80.4+/-6.6 vs 87.0+/- 5.9% VO2max in EC and PC, respectively). Lactate levels showed a similar response in both groups at low-to-moderate intensities (< 300 W), and thereafter blood lactate was significantly higher in EC. Finally, the "electromyographic threshold" (EMGT) occurred at a significantly higher intensity (p < 0.05) in PC when compared to EC (64.7+/-14.2 vs 56.0+/-14.9% VO2max, respectively). It was concluded that, in comparison with EC, PC exhibit some remarkable physiological characteristics such as a high VT2, an important reliance on fat metabolism even at high power outputs, and several neuromuscular adaptations.  相似文献   

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The incidence of thigh pain was investigated in 51 joints implanted with model Y or YII cementless total hip system. The 51 patients were followed for one or more years after surgery. Twenty-six out of 51 implanted with the model Y, and the other 25 with the model YII. Thigh pain appeared in 11 out of 26 patients (43%) replaced by model Y and in only 2 out of 25 (8%) replaced by model Y II. The difference in the incidence of thigh pain was attributed to the difference in the extent of the press fit of the stem, stress distribution and postoperative activity. To prevent thigh pain, a favorable press fit must be achieved during surgery, and the excessive weight-bearing must be restricted in postoperative course. In our improved stem design, stress is distributed uniformly on the interface between the bone and the stem resulting in reduction of thigh pain.  相似文献   

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PURPOSE: Vein pouch aneurysms are the most commonly created experimental lesions in neuroendovascular research. We sought to determine whether an experimental aneurysm that is derived from a pancreatic elastase-digested arterial sac (EDASA) models the histology and morphology of human cerebral aneurysms more accurately than the vein pouch aneurysm does. METHODS: EDASAs were created in the common carotid arteries of four rabbits, and vein pouch aneurysms were created in the common carotid arteries of four pigs. Five recently ruptured human cerebral aneurysms were obtained at autopsy. Identical histologic preparations were made for all specimens, and a vascular pathologist performed blinded histologic analyses. Morphologic dimensions were measured with a micrometer at 40-fold magnification. RESULTS: In each human cerebral aneurysm, there was complete absence of internal elastic lamina and tunica media, and none showed evidence of mural inflammation or neointimal proliferation. Average wall thickness was 51 microm. All vein pouch aneurysms had a well-developed internal elastic lamina and tunica media, and all exhibited profound inflammation and neointimal proliferation. Average wall thickness was 290 microm. EDASAs were devoid of internal elastic lamina, their tunica medias were mildly atrophic, and the sac walls contained only mild inflammation and neointimal proliferation. Average wall thickness was 46 microm. CONCLUSIONS: EDASAs model the morphologic and histologic characteristics of human cerebral aneurysms more accurately than vein pouch aneurysms do.  相似文献   

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Reports of lymphangiectases that occur in lesions of morphea are rare. We describe a 24-year-old woman with a solitary morphea profunda associated with lymphangiectasia. Unlike previously reported cases, our case showed lymphatic dilatation resembling Swiss cheese and developed around a milium.  相似文献   

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We report a rare case of gastritis cystica profunda (GCP) accompanied by carcinoma that developed in a 51-year-old Japanese man without antecedent gastric surgery. The polypoid tumor was located in the upper body of the resected stomach. Histologically, it was characterized by herniation of surface epithelium and cystic glands in the submucosa, muscularis propria, and subserosa. Marked chronic atrophic gastritis was found throughout the stomach, and dysplastic epithelia and a few adenocarcinoma cells were found in the deeper parts of the GCP. The Ki-67, p53, and p21WAF1/CIP1 labeling indices for the deeper part of the GCP were higher than those for the superficial parts or the surrounding mucosa, suggesting that both epithelial cell proliferation and p53-dependent p21WAF1/CIP1 expression in DNA-damaged cells, which might be associated with gastritis, are enhanced in line with penetration of glands. The underlying mechanisms might be linked in a chain of factors leading to malignancy.  相似文献   

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Septal perforation is an avoidable complication of septal surgery, but it can also occur because of a variety of traumatic, iatrogenic, caustic, or inflammatory reasons. Symptoms usually are related to disruption of the normally laminar flow of air through the nasal passages. Crusting, bleeding, parosmia, and neuralgia can develop, leading the patient to seek medical care. When local hygiene and conservative care are unsuccessful in relieving symptoms, closure of the perforation is considered. Repair is often difficult because of the limited exposure and limited amounts of friable mucosa with impaired vascular supply. The failure of attempted closure of septal perforations can be as high as 80 percent. The authors have developed a graduated approach to the closure of septal perforations that tailors the surgical approach to the size and location of the defect. Perforations 0.5 to 2.0 cm in size were closed in 92.9 percent (13 of 14) of patients using an extended external rhinoplasty approach and bilateral posteriorly based mucosal flaps. Larger perforations (2.0 to 4.5 cm) were closed in 81.8 percent (18 of 22) of patients by a two-staged technique, using a midfacial degloving approach to medially advance posteriorly based, expanded mucosal flaps. With careful preoperative management and selection of the appropriate surgical technique, even moderate-to-large perforations can be repaired reliably with limited operative morbidity.  相似文献   

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Pancreatic abscesses are a frequent complication of acute pancreatitis and their percutaneous drainage is usually accepted. A 76 years-old male patient admitted for acute pancreatitis (Ranson 3 at admission) has been treated with conservative therapy and percutaneous US directed drainage of the abscess, located between the tail of the pancreas and the gastric fundus. This kind of drainage was able to empty the abscess satisfactorily but it caused the onset of a gastrocutaneous fistula. This one was sutured on the gastric side by metal clips placed by gastroscopy. The patient was discharged on the 60th day in a good condition. An X-ray investigation with gastrografine before the drainage removal is therefore recommended.  相似文献   

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PURPOSE: We report a patient with recurrent episodes of severe periumbilical pain accompanied by headache, pallor, dizziness, and visual hallucinations who was subsequently diagnosed as having abdominal epilepsy and a bilateral sylvian cortical malformation. METHODS AND RESULTS: During an EEG examination, the patient had a simple partial seizure, manifested as intense abdominal pain. The ictal EEG showed a focal electrographic seizure arising from the left frontotemporal region. Computed tomography scan was normal; however, magnetic resonance imaging (MRI) revealed asymmetric lesions involving both sylvian fissures compatible with polymicrogyria. Onset of treatment with sodium valproate was followed by a significant reduction of seizures. CONCLUSIONS: Abdominal epilepsy should be suspected in adolescents or adults with paroxysmal episodes of abdominal pain associated with migraine-like symptoms. EEG and MRI investigations are indicated. A developmental brain disorder should be considered as a possible etiology.  相似文献   

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BACKGROUND AND AIMS OF THE STUDY: Surgical treatment of functional tricuspid regurgitation associated with advanced valvular disease remains controversial, mainly due to the difficulty in choosing between valve replacement or reconstructive surgery. Failure to correct tricuspid regurgitation during valvular surgery carries a poor prognosis, as reoperation may represent a significant risk to the patient. Thus correct tricuspid valve surgery is vital to achieve improved early and long-term clinical results. METHODS: A total of 142 patients underwent concomitant tricuspid annuloplasty with mitral valve replacement and their clinical outcome was assessed. RESULTS: Overall hospital mortality rate was 11.3%. Seven patients died during follow up. The overall actuarial survival rate for 10 years was 74.1 +/- 14.2%. Postoperatively, 75.8% of the patients had no residual tricuspid insufficiency, while 24.2% had first- or second-degree tricuspid insufficiency and were treated medically. All patients were in NHYA functional class I or II postoperatively. CONCLUSION: Clinically, it is important to assess the severity of functional tricuspid insufficiency before and/or during the operation. Bicuspidalization annuloplasty for functional tricuspid insufficiency has provided good results, with a low incidence of reoperation and significant clinical improvement. The technique could be used in most patients with functional tricuspid regurgitation.  相似文献   

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Polyarteritis rarely involves the cerebral vasculature, and has not been reported to have an initial presentation with intracerebral aneurysms. We describe the first case of polyarteritis presenting with symptomatic intracerebral aneurysms. A literature review from 1966 to 1997 identified 5 additional cases with evidence of intracerebral aneurysms and polyarteritis. The cases reviewed all had evidence of longstanding systemic symptoms suggestive of polyarteritis prior to diagnosis. Polyarteritis with intracerebral aneurysms is associated with significant morbidity and mortality, and therefore must be recognized and treated early.  相似文献   

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