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41.
The pathophysiology of disseminated intravascular coagulation 总被引:8,自引:0,他引:8
42.
This study measured the time course of psychophysical end-stopping and compared it with the time course of masking. For a 10' D6 target on an 18' D6 pedestal, two abutting end-zone masks (each 13.5' long) covering the filter end-zones reduce masking. This facilitatory 'end-stopping' effect was measured over a range of exposure durations and stimulus onset asynchronies (SOAs). We found that psychophysical end-stopping has a delayed onset which is around 70-100 ms after stimulus onset, in contrast to masking which is robust immediately after stimulus onset, suggesting intracortical feedback processes in the generation of psychophysical end-stopping. The development course of psychophysical end-stopping is relatively long and lasts for approximately 150-200 ms after stimulus onset, in contrast to that of masking which lasts for approximately 100-150 ms. Our results also showed that end-stopping occurs only when the center mask and the end-zone masks have sufficient temporal overlap, possibly indicating that the feedback process for generating end-stopping is triggered by the activation of the spatial filter center by the center mask. These results are in tune with current knowledge of intracortical feedback modulating activities of receptive fields, and have been incorporated into our model to describe the temporal dynamics within end-stopped spatial filters. 相似文献
43.
Strabismic amblyopes show losses in positional acuity that cannot be explained by their resolution or contrast sensitivities. One hypothesis for these losses is a reduction in the density of cortical neurons that are driven by the amblyopic eye (cortical undersampling). The question this study addressed was whether the foveal representation of the amblyopic eye is undersampled in the cortex of strabismic amblyopes. In order to assess spatial sampling psychophysically, we recorded the perceived orientation of a stationary grating as a function of grating orientation and frequency in three strabismic amblyopes. To ensure high retinal contrast, the grating was imaged on the fovea of each observer using a laser interferometer. We found that the strabismic amblyopes misperceived the orientation of the grating at spatial frequencies that are a factor of two to six lower than the sampling frequency of the foveal cones. Since the retina and LGN in strabismic amblyopes are presumably normal, this result suggests sparse cortical sampling in the foveal representation of the amblyopic eye. Undersampling by cortical neurons may contribute to the spatial distortions present in strabismic amblyopic eyes. 相似文献
44.
R Pregazzi C Bouchè G Ricci F G Toffoletti R Levi D'Ancona F Barciulli 《Minerva ginecologica》1991,43(7-8):335-339
This study concerns clinical data of 142 women, who were subjected to functional evaluation of perineum during the last part of pregnancy. The 16 cases characterized by synergic activation, during the examination of perineal muscles ("perineal testing"), of antagonist muscles ("inverted control"), were examined taking into account data regarding evolution of labour and perineal outcome. "Inverted control" seems to influence, in this study, length of the second stage and frequency of operative deliveries whereas we can't confirm the importance of this disorder within pathogenesis of perineal obstetric complications. 相似文献
45.
Minghetti L Greco A Cardone F Puopolo M Ladogana A Almonti S Cunningham C Perry VH Pocchiari M Levi G 《Journal of neuropathology and experimental neurology》2000,59(10):866-871
The levels of 2 arachidonic acid metabolites formed either by enzymatic activity of cyclooxygenase, i.e. prostaglandin E2 (PGE2), or by free radical-catalyzed peroxidation, i.e. F2-isoprostane 8-epi-prostaglandin F2alpha (8-epi-PGF2alpha), were measured in the CSF of subjects with sporadic and familial Creutzfeldt-Jakob disease (CJD) and in brain homogenates of scrapie-infected mice. The CSF levels of both metabolites were increased in sporadic CJD (n = 52) and familial CJD (n = 10) patients when compared with a group of patients with noninflammatory disorders. Similarly, PGE2 and 8-epi-PGF2alpha levels were higher in brain homogenates obtained from C57BL/6J mice infected with the ME7 scrapie strain than in brain homogenates from control animals. As PGE2 is 1 of the most abundant prostaglandins released during inflammation and 8-epi-PGF2alpha is a quantitative marker of lipid peroxidation, our results provide in vivo biochemical evidence for the occurrence of inflammation and oxidative stress in human and experimental transmissible spongiform encephalopathies (TSEs), a concept so far based mainly on histopathological and in vitro evidence. Interestingly, in sporadic CJD patients, high CSF levels of PGE2, but not 8-epi-PGF2alpha, correlated with short survival time, suggesting that the inflammatory response correlates with the clinical duration of disease. 相似文献
46.
Radical Resection of Periampullary Tumors in the Elderly: Evaluation of Long-term Results 总被引:5,自引:0,他引:5
Bathe OF Levi D Caldera H Franceschi D Raez L Patel A Raub WA Benedetto P Reddy R Hutson D Sleeman D Livingstone AS Levi JU 《World journal of surgery》2000,24(3):353-358
Increasingly, patients of advanced age are coming for evaluation of periampullary tumors. Although several studies have demonstrated
the safety of resecting periampullary tumors in older patients, few long-term survival data have been reported. Between 1983
and 1992 various periampullary masses were resected in 70 patients over age 65 (range 65–87 years). Total pancreatectomy was
performed in 11 patients, and 59 patients underwent pancreaticoduodenectomy. The mean duration of hospitalization was 17 ±
15 days. Major complications occurred in 27 patients (39%), and operative mortality rate was 8.5%. Overall median survival
was 24 months; and 5-year survival was 25%. Perioperative outcome was compared in patients aged 65 to 74 years and in patients
≥75 years old. The older age group required longer periods in the surgical intensive care unit postoperatively, but the long-term
survival was similar in the two age groups. Radical resection with the intent to cure periampullary tumors is safe in selected
patients of advanced age, and long-term survival is in the range of expected survival for younger patients with the same tumors. 相似文献
47.
M Malvezzi C Bosetti L Chatenoud T Rodríguez F Levi E Negri C La Vecchia 《Annals of oncology》2004,15(11):1712-1718
BACKGROUND: Few data on cancer mortality have been published for Mexico over the last few decades. It is therefore of interest to conduct a systematic and updated analysis of cancer mortality in this country. PATIENTS AND METHODS: Age-standardised (world population) mortality rates, at all ages and truncated at age 35-64 years, from major cancers and all cancers combined were computed on the basis of certified deaths derived from the World Health Organization database for the period 1970-99. RESULTS: Mortality rates for all neoplasms showed an upward trend in men of all ages (from 58.2/100,000 in 1970-74 to 87.1/100,000 in 1995-99) and in middle-aged men (from 76.1 to 93.7/100,000, respectively). This reflects the rise until the early 1990s in lung cancer mortality (from 8.1/100,000 in 1970-74 to 15.6/100,000 in 1995-99) and prostate cancer (from 5.5 to 12.2/100,000, respectively). In women, overall mortality rates showed an increase between the early 1970s (75.4/100,000) and the late 1990s (82.3/100,000). Total cancer mortality rates remained low, however, compared with other American countries (e.g. 153.3/100,000 men and 108.6/100,000 women in 1999 in the United States). Truncated rates were stable (126.5/100,000 in 1970-74 and 125.8/100,000 in 1995-99), although they were much higher than overall rates, reflecting exceedingly high rates for uterine (mostly cervical) cancer mortality in middle-aged women (29.5/100,000 in 1995-99). CONCLUSIONS: Total cancer mortality in Mexico has remained comparably low on a worldwide scale, and the upward trends in mortality rates for lung and other tobacco-related neoplasms have tended to level off over the last decade. However, steady rises have been observed for other major cancers, including prostate and breast. Cervical cancer remains a major health problem in women. 相似文献
48.
The management of traumatic cervical bilateral facet fracture-dislocations with unicortical anterior plates 总被引:4,自引:0,他引:4
The goal of this study was to evaluate single-level anterior cervical discectomy and stabilization for bilateral facet fracture dislocations using bone graft and anterior titanium plates with unicortical screw fixation in the clinical setting. We conducted a retrospective review during a consecutive 6-year period of patients treated in a single institution for traumatic single-level cervical bilateral facet fracture-dislocation. All fracture-dislocations that could be aligned with traction were subsequently stabilized using an anterior cervical discectomy with bone graft and titanium unicortical locking plates. All patients were examined after operation for radiographic evidence of healing and neurologic outcome. Twenty-two patients (M:F ratio, 16:6; average age, 47.7 years) underwent an anterior cervical discectomy and stabilization with either an allograft (n = 12) or an autograft (n = 10) and a titanium unicortical locking plate. Most patients had sustained a spinal cord injury (87%) or a radicular injury (9%). The average follow-up was 32 months, with a minimum follow-up of 1 year (range, 13 to 77 months). There was one instrumentation-related failure, but all 22 patients ultimately had evidence of stability at the instrumented level on the final follow-up examination. Anterior fixation with unicortical cervical locking plates as a single procedure offers an excellent surgical alternative in the management of many cervical bilateral facet fracture dislocations in patients who can be reduced preoperatively. 相似文献
49.
Mortality from gallbladder cancer has been traditionally high in Eastern Europe, and lower in northern countries. Trends in 18 European countries, including the European Union (EU) and selected Eastern European countries, have been updated using official death certification data abstracted from the WHO database over the period 1980-1999. In the EU, age-standardized rates declined by about 30% between the late 1980s and 1999 to reach 1.8/100 000 for women, and by about 10% to reach 1.4/100 000 for men. In the Czech Republic and Hungary, rates for women were over 6/100 000 until the early 1990s, and declined by about 25% thereafter. For males, gallbladder cancer mortality showed no consistent trend, with rates over 3/100 000. Thus, a high mortality area from gallbladder cancer is still evident for both sexes in Central and Eastern Europe. The trends in mortality from gallbladder cancer are probably influenced by changes in risk factor exposure, such as diet, nutrition or tobacco, but essentially reflect more widespread and earlier adoption of cholecystectomy in the EU, since gallstones are the major risk factor for gallbladder cancer. The data also indicate the scope for further improvement of the management of gallbladder disease in Eastern Europe. 相似文献
50.
S Gallus A Altieri C Bosetti S Franceschi F Levi E Negri L Dal Maso E Conti P Zambon C La Vecchia 《Annals of oncology》2003,14(2):209-213
BACKGROUND: Tobacco smoking is one of the main risk factors for oral, pharyngeal and oesophageal cancers in developed countries. Information on the role of the tar yield of cigarettes in upper digestive tract carcinogenesis is sparse and needs to be updated because the tar yield of cigarettes has steadily decreased over the last few decades. PATIENTS AND METHODS: We analysed two case-control studies, from Italy and Switzerland, conducted between 1992 and 1999, involving 749 cases of oral and pharyngeal cancer and 1770 controls, and 395 cases of squamous-cell oesophageal carcinoma and 1066 matched controls. Odds ratios (ORs) were estimated by unconditional multiple logistic regression models, including terms for age, sex, study centre, education and alcohol consumption. RESULTS: Based on the brand of cigarettes smoked for the longest time, the multivariate ORs for current smokers compared with never smokers were 6.1 for <20 mg and 9.8 for >or=20 mg tar for oral and pharyngeal neoplasms, and 4.8 and 5.4 for oesophageal cancer, respectively. For the cigarette brand smoked in the previous six months, the ORs for >or=10 mg compared with <10 mg were 1.9 for cancer of the oral cavity and pharynx and 1.8 for oesophageal cancer, after allowance for number of cigarettes and duration of smoking. CONCLUSIONS: The present study confirms the direct relationship between the tar yield of cigarettes and upper digestive tract neoplasms, and provides innovative information on lower tar cigarettes, which imply reduced risks compared with higher tar ones. However, significant excess risks were observed even in the lower tar category, thus giving unequivocal indications for stopping smoking as a priority for prevention of upper digestive tract neoplasms. 相似文献