Emergency medical technicians' disaster training by tabletop exercise.

The objective of this study was to assess the attitudes of emergency medical technicians (EMTs) toward tabletop drills to determine the effect of tabletop simulation on the EMT student perception of disaster preparedness and management. In November 1998 and April 1999, 59 firefighters underwent 260 hours of EMT intermediate level training at the National Cheng Kung University Hospital in Tainan, Taiwan. All participants had experience in field disaster exercise training before they attended this EMT training course. The EMT courses included a disaster and mass-casuality incident program. A 9-item questionnaire was completed by the 59 EMTs before (for field exercise) and after undergoing the tabletop drills. The results of the survey revealed that the field operation exercise could not provide adequate provisions to link the results of disaster exercises to appropriate changes in terms of training, equipment, supplies, and plans. Field operation failed to show the ability of others to fill in during the absence of key officials. Tabletop drilling provided better performance for these 2 issues. Tabletop exercise also provided a better chance than field exercise to evaluate the response without the use of telephones, which are not always reliable in real emergency situation. For disaster exercises, limitations of field operation drills such as communications, coordination, assignment of responsibilities, and postevent mitigation priorities were noted, and tabletop drills provided additional benefits for these settings. Large-scale effect evaluation of different drills may be necessary to design future disaster preparedness programs.

Oxidative stress in humans during work at moderate altitude.

Increased oxidative stress has been associated with work at high altitude; however, it is not known whether oxidative stress is a significant problem at moderate altitudes. The oxidative stress indicators, breath pentane (BP), 8-hydroxydeoxyguanosine (8-OHdG), oxygen radical absorption capacity (ORAC), 4-hydroxynonenal (4-HNE), malondialdehyde (MDA), and lipid peroxides (LPO) were measured in breath, blood and urine samples of U.S. Marines engaged in moderate altitude ( approximately 3000 m) cold weather field training. The test subjects were divided into a placebo and four antioxidant supplement groups (n = 15/group) and received the following supplements for 28 d: 1) vitamin E, 440 alpha-tocopherol equivalents (alpha-TE); 2) vitamin A, 2000 retinol equivalents (RE) of beta-carotene; 3) vitamin C, 500 mg ascorbic acid; 4) a mixture of 440 alpha-TE, 2000 RE of beta-carotene, 500 mg ascorbic acid, 100 microg selenium and 30 mg zinc daily. Strenuous work ( approximately 23 MJ/d) in cold weather at moderate altitude was accompanied by increases in several indicators of oxidative stress that were not effectively controlled by conventional antioxidant supplements. The group receiving the antioxidant mixture exhibited lower BP (P < 0. 05) compared with those receiving single antioxidant supplements; however, not all markers of oxidative stress responded like BP. Because these markers did not respond in the same manner, it is important to include markers from more than one source to assess the effect of supplemental dietary antioxidants.

High rate of hepatitis C virus infection in an isolated community: persistent hyperendemicity or period-related phenomena?

We investigated underlying risks for hyperendemic hepatitis C virus (HCV) infection among the 1853 inhabitants of a mountainous village in Eastern Taiwan with high prevalence of HCV and hepatitis B virus (HBV). Among the 80 selected adults, we found that having resided away from the village before 1985 was protective against HCV infection, while residing in the village after 1985 posed little risk for HCV infection to children and young adults < 30 years of age. Among the 559 school children 7 through 14 years of age, anti-HCV prevalence was 1.9%, and the HBV carrier rate was 29%. Following up 270 children 1 year later, we found that new HCV infection occurred in 0.74% and new or repeated HBV infection occurred in 6.5% of the children, indicating distinct transmission patterns between HBV and HCV. Children of anti-HCV-positive mothers were either anti-HCV-negative or were infected by distinct genotypes of HCV from those infecting their mothers; most married couples in whom both were infected, were infected by HCV of discordant genotypes, indicating negligible importance of sexual or vertical HCV transmission. A case-control study comparing 13 anti-HCV-positive and 53 anti-HCV-negative children showed that having received parenteral medication in local clinics was a significant risk for HCV infection. Our data indicate that, unlike the case of HBV, HCV transmission by vertical or sexual route, or through casual contact are extremely inefficient, and our data further suggest that HCV hyperendemicity is unlikely to persist as a result of the more stringent practice of parenteral precautions in nearly all aspects of daily life.

Effect of omitted confounders on the analysis of correlated binary data.

Marginal analysis using the generalized estimating equation approach is widely applied to correlated observations, as occur in studies with clusters and in longitudinal follow-up of individuals. In this article, we investigate the effect of confounding in such models. We assume that a risk factor x and a confounder z are related by a generalized linear model to the outcome y, which can be binary or ordinal. In order to investigate confounding arising from the omission of z, a joint structure for x and z must be specified. Modeling normally distributed (x,z) as sums of between- and within-individual (or cluster) components allows us to incorporate different degrees of between- and within-individual correlation. Such a structure includes, as special cases, cohort and period effects in longitudinal settings and random intercept models. The latter situation corresponds to allowing z to vary only on the between-individual (or cluster) level and to be uncorrelated with x, and leads to attenuation of the coefficient of x in marginal models with the logit and probit links. More complex situations occur when z is allowed to also vary on the within-individual (or cluster) level and when z is correlated with x. We examine the model specification and the expected bias when fitting a marginal model in the presence of the omitted confounder z. We derive general formulas and interpret the parameters and results in an ongoing cohort study. Testing for omitted covariates is also discussed.

Ethnic differences in immune responses to hepatitis B vaccine.

A national vaccination program against hepatitis B virus (HBV) to immunize every newborn was initiated in Taiwan in 1986. A serologic survey of 1,812 fully vaccinated children residing in four aboriginal villages and four adjacent nonaboriginal Han Chinese rural villages was conducted in 1993. Children in three of the four aboriginal villages had significantly lower titers of antibody against hepatitis B surface antigen (anti-HBs) than did children in the nonaboriginal villages. Evaluation of cold chain operation for vaccine storage and transport suggested that cold chain failure was not responsible for the fact that children residing in the more remote aboriginal villages had lower mean titers of anti-HBs. However, children whose parents were both aborigines had lower anti-HBs mean titer than did children whose parents were both ethnic Han Chinese. Children of mixed parental origins had intermediate mean titer of anti-HBs. Serologic responses to Japanese encephalitis virus and diphtheria vaccines did not show such correlation with ethnic groups, indicating that the determinant for HBV hyporesponsiveness among the aboriginal children is distinct from that of other childhood vaccines. It was therefore concluded that host factors pertaining to ethnic origin might be responsible for the hyporesponsiveness to HBV vaccine in the aboriginal populations. This finding, if substantiated with further prospective studies, might provide possible means for more targeted trials to improve vaccine response and to reduce vaccine failure among these well-defined ethnic groups.

A family cluster of an immune escape variant of hepatitis B virus infecting a mother and her two fully immunized children.

A hepatitis B virus (HBV) immune escape variant which results from a substitution of glycine by arginine at position 145 (arginine-145) in the immunodominant neutralization epitope of the S protein was found to infect one child in a seroepidemiologic survey of 1,812 vaccinated children. The child's mother and a younger brother were also infected by the same HBV variant, despite a greater than accepted level of protective antibody (anti-HBV surface antigen) in both the index child (30 mIU/ml) and the brother (> 20,000 mIU/ml). Our findings suggest the perinatal or horizontal transmission of the arginine-145 HBV variant from mother to child, but the ability of this variant to propagate among the vaccinated children remains unknown.

Estimating the risks and prevalence of hypertension in a suburban area of Beijing.

Community-oriented primary care (COPC) provides a framework for identifying and addressing a defined community's health and health care needs. The research reported upon here is based on a community health survey in a new suburban neighborhood (Tayuan region) in the Haidian district of Beijing, conducted by the Beijing Medical University Department of Preventive Medicine and Health Care, to serve as a basis for planning health care services for the residents in that community. The analyses focus on the prevalence and predictors of hypertension among older adult residents (those 45 years of age and older). Based on logistic regression analyses, the odds ratios (in parentheses) confirm that individuals with a family history of cardiovascular disease were more likely to have been diagnosed as hypertensive (1.57). Hypertensives were also more likely to have uncontrolled systolic (3.85) or diastolic (4.75) blood pressure and associated behavioral and biologic risks, such as obesity (1.87) and renal damage (2.60). These risks were even greater among current or former smokers. These analyses will inform the design of community-oriented primary care interventions in that particular community in the People's Republic of China. They also signal important implications and highlight practical methods for assessing and targeting interventions in U.S. communities facing comparable, but unexamined, risks.

Second-intention healing of exposed facial-scalp bone after Mohs surgery for skin cancer: review of ninety-one cases.

BACKGROUND: Second-intention healing over exposed bone is considered by some to be subject to the complications of pain, infection, and nonhealing. OBJECTIVE: Our purpose was to determine would healing by second intention over exposed scalp or facial bone after Mohs micrographic surgery for skin cancer. METHODS: The chart records of all patients treated between 1981 and 1992 for skin cancer that resulted in exposed bone were identified. RESULTS: There were 115 wounds in 91 patients that were managed by second-intention healing, or partial closure, or both. Three cases of soft tissue infection occurred adjacent to nasal and sinus areas. The overall complication rate was 5.4% (6 of 112 cases) and consisted of localized soft tissue infections (2.7%) and poor wound healing (2.7%). There were no cases of osteomyelitis. Second-intention wound healing was successful in 95% of the wounds. CONCLUSION: The outpatient management of exposed bone after Mohs surgery is relatively safe. Relative risk factors for development of complications include (1) a history of previous x-radiation treatment for skin cancer, (2) manipulation of the operative site, and (3) an open defect located near the nose or exposed sinus cavity.