近视患者准分子激光原位角膜磨镶术后动、静态对比敏感度的变化

目的观察近视患者准分子激光原位角膜磨镶术(laserinsitukeratomileusis,LASIK)后动、静态对比敏感度的变化。方法对2002年2月～2002年6月在我院接受LASIK手术的37例近视和近视散光患者(共73眼)进行了术前,术后1、3、6个月的视力,裂隙灯,散瞳眼底,散瞳检影验光,角膜地形图,动、静态对比敏感度0.7、1.4、2.7、5.5、11、22频率段的观察。结果LASIK术后1个月动态对比敏感度和静态对比敏感度较术前普遍下降,静态对比敏感度在2.7、5.5、11(P<0.01)和22cpd(P<0.05)有显著性下降,11cpd最敏感;而动态对比敏感度则在5.5(P<0.01)、11cps(P<0.05)下降有统计学意义,11cps最敏感;≥6.25D近视组和≥2DC散光组下降更明显。术后3个月,动、静态对比敏感度各频率段逐渐恢复并超过术前水平,术后6个月继续提高。静态对比敏感度所有频率段均超过术前水平(P<0.01),而动态对比敏感度在2.7、5.5、11cps(P<0.01)超过术前水平,≤6.0D近视组和<2.0DC散光组提高更明显。频率越高,提高率越大,以22cpd和22cps最明显。而≥2DC的散光组,动态对比敏感度在术后6个月无显著提高,且1.4cps段还低于术前水平(P<0.05)。结论LASIK术后病例确实有暂时的对比敏感度下降,但是在术后3个月可恢复并超过术前水平,术后6个月有进一步提高。     

Tuberculin test

Although tuberculin test is widely used for detection ot tuberculous infection among children, there is no clear understanding about its performance and interpretation. This article has been written with the purpose of elucidating the performance and interpretation of standard tuberculin test, based on the experiences gained at the National Tuberculosis Institute, Bangalore and other centres. The standard tuberculin test involves intradermal injection of "ITU PPD RT23 with Tween 80’ on the mid-volar aspect of forearm and measurement of the maximum transverse diameter of induration after 3 days. Larger the size of induration, higher is the probability of it being due to tuberculous infection. The majority of reactions with induration size of 15 mm and above are attributable to infection with tubercle bacilli, irrespective of BCG-vaccination status. While indurations of less than 5 mm indicate absence of any kind of tuberculin sensitivity, the majority of indurations in 5–9 mm range are usually of non-tuberculous nature. An induration of 10–14 mm requires more careful interpretation. It is more likely to be attributable to infection with tubercle bacilli in case of history of contact with smear positive case or among children with clinical findings of tuberculosis. However, the size of induration in an infected child may be diminished in the presence of immuno-suppressive conditions. One should also consider the purpose of the test while interpreting the test results.     

Mortality experience among employees at a hydrometallurgical nickel refinery and fertiliser complex in Fort Saskatchewan, Alberta (1954-95)

OBJECTIVE—To study the mortality experience of workers at a hydrometallurgical nickel refinery and fertiliser complex in Fort Saskatchewan, Alberta, Canada.
METHODS—A total of 1649 male employees of Sherritt International who worked for at least 12 continuous months during the years 1954 to 1978 at the Fort Saskatchewan, Alberta hydrometallurgical nickel refinery and fertiliser complex were followed up for an additional 17 years. Mortality was ascertained from the Canadian mortality data base maintained by Statistics Canada and covered the years 1954-95. Statistics were analysed with Monson's computer program.
RESULTS—Total mortality, when compared with the Canadian population, was significantly below expectation. Fewer deaths were found for circulatory disease, ischaemic heart disease, respiratory disease, neoplasms, digestive cancer, and accidents, poisonings, and violence. Among the 718 men in the group exposed to nickel, there were no deaths due to nasal cavity or paranasal sinus cancer. Fewer deaths were found for all causes, circulatory disease, ischaemic heart disease, neoplasms and digestive cancer. Lower death rates were observed than expected for respiratory malignancies and cancer of the bronchus and lung.
CONCLUSION—No association was found in this study between exposure to nickel concentrate or metallic nickel in the hydrometallurgical refining process and the subsequent development of respiratory cancer.


Keywords: epidemiology; nickel workers; mortality     

Performance of Number-Between g-Type Statistical Control Charts for Monitoring Adverse Events

Alternate Shewhart-type statistical control charts, called g and h charts, have been developed for monitoring the number of cases between hospital-acquired infections and other adverse events, such as heart surgery complications, catheter-related infections, surgical site infections, contaminated needle sticks, medication errors and other care induced concerns. This article investigates the statistical properties of these new charts and illustrates several design considerations that significantly can improve their operating characteristics and sensitivity, including the use of with-in limit rules, a new in-control rule, redefined Bernoulli trials, and probability-based limits. These new charts are based on inverse sampling from geometric and negative binomial distributions, are simple for practitioners to use, and in some cases exhibit significantly greater detection power over conventional binomial-based approaches, particularly for infrequent events and low defect rates.     

The relations of trait anxiety, anxiety sensitivity, and sensation seeking to adolescents'' motivations for alcohol, cigarette, and marijuana use

The present study investigated relations of anxiety sensitivity and other theoretically relevant personality factors to Copper's [Psychological Assessment 6 (1994) 117.] four categories of substance use motivations as applied to teens' use of alcohol, cigarettes, and marijuana. A sample of 508 adolescents (238 females, 270 males; mean age = 15.1 years) completed the Trait subscale of the State-Trait Anxiety Inventory for Children, the Childhood Anxiety Sensitivity Index (CASI), and the Intensity and Novelty subscales of the Arnett Inventory of Sensation Seeking. Users of each substance also completed the Drinking Motives Questionnaire-Revised (DMQ-R) and/or author-compiled measures for assessing motives for cigarette smoking and marijuana use, respectively. Multiple regression analyses revealed that, in the case of each drug, the block of personality variables predicted "risky" substance use motives (i.e., coping, enhancement, and/or conformity motives) over-and-above demographics. High intensity seeking and low anxiety sensitivity predicted enhancement motives for alcohol use, high anxiety sensitivity predicted conformity motives for alcohol and marijuana use, and high trait anxiety predicted coping motives for alcohol and cigarette use. Moreover, anxiety sensitivity moderated the relation between trait anxiety and coping motives for alcohol and cigarette use: the trait anxiety-coping motives relation was stronger for high, than for low, anxiety sensitive individuals. Implications of the findings for improving substance abuse prevention efforts for youth will be discussed.     

The effect of age and density of the breast on the sensitivity of breast cancer diagnostic by mammography and ultasonography

Purpose. We studied which, age of the patient or density of the breast accounts for the sensitivity of mammography and ultrasonography (US). Furthermore we studied whether the overall impression on the density of the breast or the density in tumour area accounts for the sensitivity of mammography and ultrasonography. Materials and methods. The material consisted of 572 consecutive histologically and 5 cytologically verified breast cancer cases. Mammography and US examinations were performed immediately before breast cancer operations and information on the findings were received from the original patient files and classified as malignant or benign. The density of breast parenchyma to fatty, mixed or dense in total breast and separately in tumour area was defined by a radiologist group from the original mammograms by comparing to model mammograms. The sensitivity (Se) of mammography and US was compared in 3 age groups (26–49, 50–59 and 60–92) and in the different density classes. Results. Sensitivity of mammography increased by age (density-adjusted OR=0.2, 95%, CI 0.1–0.5) in age group 26–49 compared to age group 60–92) and with fattiness of the breast (age-adjusted OR=0.4, 95%, CI 0.1–1.0 for dense breast parenchyma in tumour area compared to fatty breast). Sensitivity of US was inversely related to age (density-adjusted OR=2.3, 95%, CI 1.0–5.2 in age group 26–49 compared to age group 60–92) and directly related with fattiness of breast (age-adjusted OR=0.5, 95%, CI 0.2–0.9 by dense breast parenchyma in tumour area compared to fatty breast). Density in the tumour area compared to total breast density was related only mariginally better sensitivity both of mammography (0.4 vs. 0.6) and of US (0.5 vs. 0.6). itConclusion. Sensitivity of both mammography and sensitivity of US are independently related both to the age of the patient and to the density of the breast. The effect of age is inverse and that of density parallel between mammography and US on sensitivity. The effect of overall breast density was close to the effect of density at the site of the tumour on the sensitivity of both mammography and US.     

Maintaining cell sensitivity to G-protein coupled receptor agonists: neurotensin and the role of receptor gene activation

In the last few years, a number of studies have brought new insights into the fundamental mechanisms of cell desensitization and internalization of G-protein coupled receptors. Such studies have demonstrated that cells remain desensitized from a few minutes to several hours, after exposure to high concentrations of agonist. However, in vivo, agonists such as hormones are always present, even in small amounts, and such long desensitization is not conceivable, since constant stimulation of cells is required for physiological responses. Under such circumstances, cells would require a means to permanently maintain sensitivity to various internal or external stimuli. In the present review, we have taken as an example the expression of the high affinity neurotensin receptor, a seven transmembrane G-protein coupled receptor, upon prolonged exposure to its agonist, and observed that cells remained sensitive only if the receptor gene was activated by the agonist. Consequently, new receptors were synthesized, and either delivered to the cell surface or accumulated in submembrane pools. This regulation takes place only after prolonged and intense agonist stimulation. Under these conditions, it is proposed that receptor turnover is accelerated in proportion to the agonist concentration in order to allow the cells to produce an adapted cellular response to external stimuli. Such mechanisms thus play a key role in cell sensitivity to hormones.     

Cumulative exposure to styrene and visual functions

BACKGROUND: Results from a 1990-1992 longitudinal study of several reinforced plastics plants showed that for those workers whose styrene exposure had decreased, color vision (CV) improved; while near visual contrast sensitivity (CS) was poorer. METHODS: In 1999, we retested these visual functions in 18 workers with good visual acuity. A cumulative exposure index (CEI), corrected for respirator use, was calculated for each worker. RESULTS: Intra-individual comparison of mandelic acid (MA) showed a significant decrease over time (Friedman; P = 0.015), but current values were not related to CEI. For CV, no significant difference was observed between 1992 and 1999; present results were not related to MA or CEI. The CS profile decreased over time, with significant differences at 3 cpd (Friedman; P < 0.05). CS did not vary with MA levels, but was significantly depressed at the intermediate frequencies among those in the upper CEIH category (Kruskal-Wallis; P < 0.05). CONCLUSIONS: These findings suggest that CS loss increases with long-term cumulative exposure, reflecting chronic damage to the neuro-optic pathways.