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91.
A novel method using a snare and bioptome to provide bidirectional control of a Gianturco coil for occlusion of a patent ductus arteriosus with a shallow ampulla and Pott's shunts is presented. This method greatly reduces the risk of coil embolization and optimizes coil position in difficult cases.  相似文献   
92.
Unintentional weight loss is an ominous sign, particularly when it occurs in the elderly; concern for malignancy is especially worrisome. In this report, we describe a 72-yr-old man who presented with weight loss and was found to have massive steatorrhea. An extensive evaluation revealed evidence of primary biliary cirrhosis (PBC), celiac disease, and small intestinal bacterial overgrowth. No malignancy was identified. The weight loss was attributed to severe steatorrhea due, in part, to intraluminal bile salt deficiency, small bowel mucosal disease, and bacterial overgrowth. Several points are discussed regarding gastrointestinal function in elderly patients with chronic liver disease secondary to PBC. The rare association between PBC and celiac disease in adults is also discussed. Finally, we suggest that bacterial overgrowth plays a significant role in the development of steatorrhea in some persons with PBC and that an assessment for bacterial overgrowth should be performed on persons with steatorrhea and PBC.  相似文献   
93.
This study investigated whether self-esteem precedes various academic behaviors and beliefs among 593 high school students (63.7% female, 60.9% African American). Measures of home and school self-esteem, grade point average, perceived academic standing and progress, and educational plans were collected by survey and archival review of grade and attendance records at the beginning (pre-test) and end of the school year (post-test). Self-esteem and academic variables differed by gender, race, and guardianship. Self-esteem related significantly to academics and absenteeism. Results suggest selected academic variables predict self-esteem even when the effects of gender, race, and guardianship are removed and pretest self-esteem scores are controlled. In conclusion, student academic performance influences subsequent academic and home self-esteem. Creation of positive academic experiences for youth may be a critical activity, since experts contend that low self-esteem is associated with subsequent behavioral problems. The markedly lower self-esteem of Native American and Hispanic youth warrants further investigation.  相似文献   
94.
Clinical manifestations of superior sagittal sinus (SSS) thrombosis are nonspecific but characterized by headache, papilledema, seizures, focal deficits, progressive coma and death. Recurrent transient focal neurologic deficit is an extremely rare manifestation in superior sagittal sinus thrombosis and the mechanism is unknown. A 45-year-old man presented with headache for two weeks and four episodes of transient (5-10 minutes) right or left hemiparesis for two days. Magnetic resonance image and transfemoral cerebral angiography revealed superior sagittal sinus thrombosis with numerous prominent collateral venous channels. There was no parenchymal lesion. After four days of heparinization, no further transient focal neurologic deficits developed. Follow-up angiography showed partial recanalization of the SSS. Possible mechanism of transient ischemic attacks in this patient is thought to be a transient functional disturbance due to a temporal reduction of tissue perfusion in the process of operating fully-enough collateral channels.  相似文献   
95.
Second-semester ultrasonography of a female fetus documented short femora and humeri and dislocation of the radii. Based on the clinical and postmortem radiological findings, autosomal-recessive omodysplasia was diagnosed. The physeal plates of the long tubular bones were assessed by computer-assisted image analysis. The dimensions and orientation of the chondrocytic lacunae in the physeal plates of the omodysplastic fetus were compared with those in the physeal plates of fetuses without gross limb abnormalities (oligohydramnios, n = 2; hydrocephalus, n = 2; Down syndrome, n = 1). The pathological characteristics of the omodysplastic physeal plates were an expanded zone of proliferating cartilage and an increased number of closely packed, small chondrocytes. We propose that a genetic, functional deficiency of the physeal cells, underlying the short-limbed dwarfism of autosomal-recessive omodysplasia, is partially compensated, albeit ineffectively, by an increased number of small chondrocytes in the proliferating zone of the physeal plate.  相似文献   
96.
This study tested the hypothesis that the receptive fields (RFs) of neurons in the adult sensory cortex are shaped by the recent history of sensory experience. Sensory experience was altered by a brief period of "whisker pairing": whiskers D2 and either D1 or D3 were left intact, while all other whiskers on the right side of the face were trimmed close to the fur. The animals were anesthetized 64-66 h later and the responses of single neurons in contralateral cortical barrel D2 to stimulation of whisker D2 (the center RF) and the four neighboring whiskers (D1, D3, C2, and E2; the excitatory surround RF) were measured. Data from 79 cells in four rats with whiskers paired were compared to data from 52 cells in four rats with untrimmed whiskers (control cases). During the period of whisker pairing, the RFs of cells in barrel D2 changed in three ways: (i) the response to the center RF, whisker D2, increased by 39%, (ii) the response to the paired surround RF whisker increased by 85-100%, and (iii) the response to all clipped (unpaired) surround RF whiskers decreased by 9-42%. In the control condition, the response of barrel D2 cells to the two neighboring whiskers, D1 and D3, was equal. After whisker pairing, the response to the paired neighbor of D2 was more than twice as large as the response to the cut neighbor of D2. These findings indicate that a brief change in the pattern of sensory activity can alter the configuration of cortical RFs, even in adult animals.  相似文献   
97.
Comparison of contaminants from different trophic levels and ecosystems   总被引:8,自引:0,他引:8  
The present paper provides an overview of the priority contaminants and media from the Greenland part of the Arctic Monitoring and Assessment Program. Levels and accumulation patterns of heavy metals, POPs and a radionuclide (137Cs) are compared from the terrestrial, freshwater and marine ecosystems. Of the nine compounds presented, seven (Cd, Hg, Se, sigma PCB, sigma DDT, sigma HCH, HCB) increased in concentration towards higher trophic levels. For these contaminants the concentrations in soil and aquatic sediment were in the same order of magnitude, whereas the concentrations in marine biota were higher than found in the freshwater and terrestrial ecosystems probably due to the presence of longer food chains. Pb and 137Cs showed the reverse pattern compared with the other compounds. The concentrations in soil and aquatic sediments decreased in the order terrestrial, freshwater and marine ecosystems, which was reflected in the biota as well. Reindeer had similar or lower levels of Pb and 137Cs than lichens. Levels of Pb and 137Cs in marine biota did not show the same clear increase towards higher trophic as found for the other analysed compounds. Greenland Inuit contains considerably less mercury but higher levels of sigma PCB, sigma DDT and HCB than other Arctic marine top consumers.  相似文献   
98.
Glaucous gulls (Larus hyperboreus) and Icelandic gulls (Larus glaucoides) were sampled in 1994 from four different areas in Greenland, three on the west coast and one on the east coast. Livers of 93 glaucous gulls and seven Icelandic gulls were analysed for polychlorinated biphenyls (PCBs, IUPAC Nos. 28, 31, 52, 101, 105, 118, 138, 153, 156 and 180), DDTs (p,p'-DDE, p,p'-DDD, p,p'-DDT), hexachlorocyclohexanes (alpha-, beta- and gamma-HCH), hexachlorobenzene (HCB) and trans-nonachlor (TNC). The overall geometric means of the concentrations found in glaucous gull liver were for sigma PCBs 388 (range 20-5557), for sigma DDTs 363 (17-8604), sigma HCHs 7.4 (1-53), HCB 47 (4-594) and trans-nonachlor 19 (3-187) micrograms kg-1 wet wt., respectively. The geometric means of concentrations in Icelandic gull liver were for sigma PCBs 112 (24-435), for sigma DDTs 95 (25-298), sigma HCHs 2.9 (1.4-5.2), HCB 22 (8-58) and trans-nonachlor 5.1 (2.4-8.6) micrograms kg-1 wet wt., respectively. Significantly (P = 0.05) higher concentrations of PCBs, DDTs and HCHs were found in glaucous gulls at Ittoqqortoormiit at the east coast than in gulls from Qeqertarsuaq at the west coast of Greenland. This tendency was also seen for HCB and trans-nonachlor, but the differences were not statistically significant (P = 0.05). A decreasing trend in organochlorine concentrations followed the East Greenland Current, flowing from north to south down the east coast and to the north on the west coast. Gulls taken from the most northerly sampling area of the west coast, however, showed slightly higher concentrations than those from the central west coast. There appeared to be a tendency for higher concentrations to be found in males than females, and in adults compared to young glaucous gulls, but the differences were not statistically significant (P = 0.05). The concentration ranges found in gulls from Greenland were similar to those reported previously for gulls from northern Norway and Russia. A principal component analysis revealed no obvious link between the presence of higher chlorinated PCBs and higher PCB concentrations in glaucous gulls. Significantly higher proportions of higher chlorinated PCBs were found in glaucous gulls than in Icelandic gulls, and in adult glaucous gulls compared to young gulls of 1-2 calendar years. As no such difference was found between female and male gulls it seems that PCBs of all degrees of chlorination may be passed equally well from mother to offspring.  相似文献   
99.
FF 《网络与信息》2009,(8):11-11
我们知道,BT下载的优点是下载速度快、资源分布广、对服务器造成的负担较小,但缺点是每一个BT资源都有时效性.例如:两个月前的BT资源,现在多半是无效的,也就是通常说的"没种子了".而电驴(eMule)则不然,它的特点就是可使用多个途径搜索下载的资料源.由ED2K、来源交换、Kad共同组成一个可靠的网络结构.虽然速度上可能不及BT,但可以搜索得到更多的资源(包括一些N年前的东东).快车在其3.0版中加入对电驴的支持,无疑又将其可用性提高了一大截.至此,快车下载软件可以支持BT、eMule、FTP、HTTP等绝大部分下载方式.  相似文献   
100.
The capacity of the Boophilus Yolk pro-Cathepsin (BYC) to induce a protective immune response in cattle against Boophilus microplus infestation was tested by vaccination experiments and by inoculation of monoclonal antibody (MAb) against BYC into fully engorged tick females. In immunization experiments the measurement of various biological parameters demonstrated a partial protection against B. microplus. A continuous decrease in the levels of specific antibodies was observed over 11 months when six bovines were maintained in field conditions. The inoculation of the MAb into tick females produced a dose-dependent decrease in oviposition and survival of the ectoparasite compared to the control.  相似文献   
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