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41.
Corneal pathophysiology with contact lens wear   总被引:2,自引:0,他引:2  
Contact lens wear induces a wide spectrum of changes in the appearance and function of the cornea. The most salient effect of lens wear is the hypoxically induced reduction in the rate of metabolic activity of the corneal epithelium and its sequellae. Other important alterations to corneal health associated with contact lens wear may be caused by antigenic and toxic stimuli, mechanical forces, osmotic effects and carbon dioxide retention. Perhaps the most important task facing the contact lens clinician is to distinguish between an acceptable state of physiological modification and an anomalous or pathological state of hypofunction. In this article, we review the assortment of corneal changes primarily on the basis of the causative agents and time scale with reference to the physical and chemical processes leading to the observed signs or symptoms. This procedure allows a strong foundation for understanding the etiology and management principles for the variety of effects that contact lenses may have on the cornea.  相似文献   
42.
Compulsory health insurance schemes have received attention recently as a means of creating a reliable extra-budgetary source of health care funding. Yet, the full implications of such schemes in a developing country context are unclear; in particular, the impact on and relationship with private sector providers has infrequently been explored. This study examines patterns of public and private sector utilization under the Civil Servants' Medical Benefit Scheme (CSMBS) in Bangkok, Thailand. The CSMBS currently provides limited reimbursement for private inpatient care, but recent proposals suggest increasing benefit levels for care sought in the private sector. The study shows that despite high level of cost recovery in the public sector, charges were much lower than those in the private sector. Different patterns of diagnosis in the two sectors were found with private hospitals tending to treat a less complex case mix. Within the private sector, there was a limited tendency to specialize in certain types of care. It is concluded that under the current payment mechanism of fee-for-service reimbursement, measures to enhance access to private sector care should be approached with caution. In the long run, the scheme should merge with the recently established social security scheme.  相似文献   
43.
Global and regional cerebral blood flow (CBF) were evaluated with single photon emission computerized tomography (SPECT) utilizing both 133Xenon (133Xe) (47 subjects, 47–82 years old) and 99Tc-hexamethylpropyleneamine oxime (99Tc-HMPAO) (27 subjects, 47–80 years old). The 133Xe results showed: among total subjects, no age-related decline in global CBF, but a significant regional decline in the occipital lobe (p < 0.05); among men, significant age-related declines in global, frontal, temporal, occipital and right hemisphere CBF (all p < 0.05); among women, no age-related decline in global or regional CBF. The 99Tc-HMPAO results showed no age-related decline in either global or regional perfusion among total subjects, men or women. These results suggest that age-related global and regional (including frontal lobe) CBF declines do not occur in healthy control subjects after the age of 45 years. However, gender differences in age-related CBF changes warrant further study.  相似文献   
44.
Six of 175 Angus heifers died after ingesting excessive amounts of Durango root (Datisca glomerata). Animals had rumens full of Durango root, were extremely lethargic, and had diarrhea prior to death. The animals had nonspecific postmortem lesions. This case is discussed in light of previous findings from trials in which Durango root was experimentally fed to cattle.  相似文献   
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An outbreak of Salmonella dublin infection occurred in England and Wales in October to December 1989. Forty-two people were affected, mainly adults, and most lived in south-east England. Microbiological and epidemiological investigations implicated an imported Irish soft unpasteurized cows' milk cheese as the vehicle of infection. A case-control study showed a statistically significant association between infection and consumption of the suspect cheese (p = 0.001). Salmonella dublin was subsequently isolated from cheeses obtained from the manufacturer's premises. Initial control measures included the withdrawal of the cheese from retail sale and a Food Hazard Warning to Environmental Health Departments, as well as a press release, from the Department of Health. Subsequently, a decision was taken by the manufacturer to pasteurize milk used in the production of cheese for the UK market and importation of the cheese resumed in June 1990.  相似文献   
49.
Summary: We report a series of 8 patients with ictal déjà vu. Subdural strip electrocorticographic (ECoG) monitoring localized the ictal epileptogenic focus as follows: right (n = 6) and left (n = 2) mesiotemporal lobe. In all 8 patients, the left hemisphere was dominant for language function based on intracarotid amytal testing. In 6 right-handed patients, ictal déjà vu was associated with a right temporal lobe focus. However, in the 2 left-handed patients, the ictal focus was left temporal lobe. Although ictal déjà vu localizes the epileptic focus to temporal lobe, this experiential phenomenon appears to lateralize to the hemisphere nondominant for handedness.  相似文献   
50.
The usual form of the Mantel–Haenszel test statistic assumes independent observations. This is inappropriate for data from a stratified multistage survey. Two alternative adjustments to the test statistic are developed to deal with this: (a) a modification of the effective sample size for each row of each table, using the design effects, extending a method proposed by Donald and Donner for familial aggregation studies; (b) a Taylor series approximation to the variance of the square root of the numerator of the Mantel-Haenszel statistic. Both methods are evaluated by application to both simulated and real data. The two methods perform equally well, and offer a considerable improvement over the unadjusted test statistic when observations from the same cluster are highly correlated. A simplified adjustment is also considered, as is the need for correction to the variance of the odds ratio estimator.  相似文献   
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