Sparse-sampling of gratings in the visual cortex of strabismic amblyopes

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.     

Functional evaluation of the perineum in pregnancy. Inversion of control

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.     

Increased brain synthesis of prostaglandin E2 and F2-isoprostane in human and experimental transmissible spongiform encephalopathies

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.     

Radical Resection of Periampullary Tumors in the Elderly: Evaluation of Long-term Results

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.     

Trends in cancer mortality in Mexico, 1970-1999.

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.     

Clonogenic survival and cytokinesis-blocked binucleation of skin fibroblasts and normal tissue complications in soft tissue sarcoma patients treated with preoperative radiotherapy.

BACKGROUND AND PURPOSE:To evaluate the clonogenic and cytokinesis-blocked assays in skin fibroblast cultures for their utility as tools for predicting normal tissue responses in soft tissue sarcoma (STS) patients treated with preoperative radiotherapy. PATIENTS AND METHODS:Dermal fibroblast strains were established from skin biopsies of 26 STS patients who received preoperative radiotherapy. Cultures were subjected to the colony forming and cytokinesis-blocked assays after low (approximately 0.02 Gy/min) dose-rate 60Co -irradiation. Fibroblast radiosensitivity was expressed as the dose for 1% clonogenic survival, D0.01, based on colonies/clusters with >or=10 cells. Fibroblast proliferative capability was represented by binucleation index (BNI) and genomic damage was expressed in terms of micronucleus frequency. Wound healing complications (WHC) and subcutaneous fibrosis were the clinical endpoints examined. The ability of each in vitro parameter to detect patients at high risk of a given normal tissue complication was assessed using receiver operating characteristic (ROC) analysis. RESULTS:While fibroblasts from patients without WHC were marginally more radiosensitive than fibroblasts from patients with WHC (P=0.08), the reduction in BNI following a dose of 2.4 Gy was significantly higher in strains from patients without WHC compared to those from patients with WHC (P=0.01). The area under the ROC curve (c-index) is indicative of the power of discrimination of D0.01 and BNI for WHC, and was found to be 0.68 and 0.79, respectively. Subcutaneous fibrosis was not associated with D0.01 (rs=0.09, P=0.66) and the percent reduction in BNI after 2.4 Gy (rs=-0.19, P=0.36). Micronucleus frequency did not reflect differences in normal tissue responses. CONCLUSION:These data suggest that it is the ability of fibroblasts to undergo one-three divisions in vitro following radiation treatment that may reflect the development of wound healing morbidity or subcutaneous fibrosis in this population of patients.     

The management of traumatic cervical bilateral facet fracture-dislocations with unicortical anterior plates

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.     

The recent decline in gallbladder cancer mortality in Europe.

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.     

Cigarette tar yield and risk of upper digestive tract cancers: case-control studies from Italy and Switzerland.

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.     

Occupational and environmental risk factors for idiopathic pulmonary fibrosis: a multicenter case-control study. Collaborating Centers

Occupational exposures were investigated in a multicenter case-control study of clinically and histologically diagnosed idiopathic pulmonary fibrosis (IPF), a chronic diffuse interstitial lung disease of unknown etiology. Results are based on 248 cases, aged 20-75 years, diagnosed at 16 referral centers between January 1989 and July 1993. There were 491 controls ascertained by random digit dialing and matched to cases on sex, age, and geographic region. Data were collected using a standard telephone questionnaire. Occupational factors were based on a detailed history of jobs lasting 6 months or more and job activity, hobby, and specific substance checklists. Several occupational factors, adjusted for age and smoking in conditional multivariate logistic regression analyses, were significantly associated with IPF: farming (odds ratio (OR) = 1.6, 95% confidence interval (CI): 1.0, 2.5); livestock (OR = 2.7, 95% CI: 1.3, 5.5); hairdressing (OR = 4.4, 95% CI: 1.2, 16.3); metal dust (OR = 2.0, 95% CI: 1.0, 4.0); raising birds (OR = 4.7, 95% CI: 1.6, 14.1); stone cutting/polishing (OR = 3.9, 95% CI: 1.2, 12.7); and vegetable dust/animal dust (OR = 4.7, 95% CI: 2.1, 10.4). Interaction was detected between smoking and exposure to livestock (p = 0.06) and farming (p = 0.08). Results confirm previous studies showing increased risk associated with dusty environments.