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At least 37 records · Page 2Linked to original sources
PubMed1990

Efficacy of prism adaptation in the surgical management of acquired esotropia. Prism Adaptation Study Research Group.

Prism adaptation, the preoperative use of prisms in acquired esotropia to determine the maximum angle of strabismus and to estimate fusional potential, has been suggested as a method of improving the results of initial surgery and minimizing the rate of reoperation. We performed a prospective, randomized, multicenter clinical trial of the effectiveness of prism adaptation. Two levels of randomization were used. Sixty percent of the patients underwent prism adaptation and 40% did not. Of those who responded to prisms with motor stability and sensory fusion, half underwent a conventional amount of surgery and half underwent augmented surgery based on the prism-adapted angle of deviation. Success rates were highest (54 [89%] of 61 patients) in prism adaptation responders who underwent augmented surgery and lowest (92 [72%] of 127 patients) in patients who did not undergo prism adaptation. Prism responders had better results with augmented surgery than with conventional surgery (54 [89%] of 61 patients vs 53 [79%] of 67 patients, P = .23). Our results indicated a significant beneficial overall effect of prism adaptation in patients with acquired esotropia (success rates, 83% vs 72%, P = .04). Although the process requires some additional time and effort, it appears to result in a higher rate of satisfactory alignment.

Adaptation, Ocular↗
PubMed1997

Linkage study of chromosome 6p in sib-pairs with schizophrenia.

Following reports of linkage between schizophrenia and markers in the chromosomal region 6p24-22 we have studied nine microsatellite markers spanning 40 cM of this region in our sample of 102 affected sibling pairs from 86 families. Allele sharing identity by descent was examined using likelihood based sib-pair analysis as implemented by the program SPLINK. No evidence for linkage was obtained and the highest lod score was only 0.192 for D6S309. We conclude that if there is a susceptibility locus for schizophrenia in this region then its effect size is so small as to render our study insufficiently powerful to detect it.

Adult↗
PubMed1996

Testing for individual and population equivalence based on the proportion of similar responses.

This paper focuses on the classical problem of comparison of treatment effects. We show that we can base a simple and intuitive approach to comparison of two treatments on the proportion of similar responses. This approach is equivalent to the standard comparison of the treatment means in the normal case with equal known variances, but is quite different in other cases. Our approach applies under two different settings: testing a null hypothesis of no treatment difference against an alternative hypothesis of a difference, and testing the null hypothesis of at least a specific difference against an alternative hypothesis of equivalence. We develop our approach both for parallel groups (independent samples), and cross-over (paired samples) studies. The two situations give rise to the known concepts of population and individual equivalence. We present a graphical procedure to supplement the method.

Cross-Over Studies↗
PubMed2000

Assessing the potential for bias in meta-analysis due to selective reporting of subgroup analyses within studies.

Subgroup analysis is frequently used to investigate heterogeneity in meta-analysis. Subgroup data are not always available, and researchers should record what data were available for each trial. If data were not available, and it is known that the subgroup data were collected, the potential for selective reporting should be considered. Bias due to selective publishing of reports is widely recognized in meta-analysis. In contrast, selective reporting within studies is little discussed but potentially important. We explored this problem by evaluating the effect of potential bias in subgroup analysis due to within-study selective reporting with an existing meta-analysis. The review addressed malaria chemoprophylaxis in pregnancy. The conclusion in the original review, that benefit is limited to primigravidae, was based on subgroup analysis using the three trials out of five which reported on subgroups. We developed a method of sensitivity analysis that imputes data for the missing subgroups to assess the robustness of the results and the conclusions drawn. In this particular example, our analysis indicates that the estimate of effect reported in the review is most likely to overestimate the true effect and the conclusion that benefit is limited to primigravidae may be false.

Bias↗
PubMed2000

National cancer database report on chondrosarcoma of the head and neck.

BACKGROUND: Management of chondrosarcoma of the head and neck is largely based on single-institution reports with small numbers accrued over several decades. METHODS: The American College of Surgeons' National Cancer Data Base included 400 cases of chondrosarcoma of the head and neck diagnosed between 1985 and 1995. Chi square analyses of selected contingency tables and Wilcoxon regression analyses of selected survival stratifications were performed. RESULTS: Histologic types included conventional (80.8%), myxoid (10.5%), and mesenchymal (8.8%). The mesenchymal and myxoid subtypes were rare among white patients (17.1%) and more common among African-American (31.8%) and Hispanic patients (44.9%). Treatment was most commonly surgery alone (59.5%) and surgery with irradiation (21.0%). Disease-specific survival was 87.2% at 5 years and 70.6% at 10 years. Worse 5-year survival was associated with higher grade (67.3%), regional or distant spread (71.0%), and the myxoid (45.0%) or mesenchymal (53.2%) subtypes. CONCLUSIONS: Chondrosarcoma of the head and neck encompasses a variety of lesions that differ substantially by demographic and tumor characteristics. Individual tumors can be classified further according to site of origin, histologic subtype, and tumor grade, which can be used to predict biologic behavior and prognosis.

Adult↗
PubMed1989

Can the provision of information to patients with osteoarthritis improve functional status? A randomized, controlled trial.

After we assessed the functional status of 439 patients with osteoarthritis, we randomly assigned them to 1 of 3 intervention groups or to a control group. The interventions consisted of providing information, and differed only in the method of delivery: by phone, in person at the clinic, or both. Physical health improved (P = 0.02), pain was reduced (P = 0.02), and psychological health improved marginally (P = 0.10) in patients contacted by phone compared with those not contacted by phone. In those contacted only at the clinic, physical health worsened (P = 0.02), but neither pain (P = 0.80) nor psychological health (P = 0.90) differed from the values in patients not contacted at the clinic. We conclude that telephone contact is a useful intervention that can enhance the functional status of patients with osteoarthritis.

Consumer Behavior↗
PubMed2001

The relationship between sweetness preference and dental caries in mother/child pairs from Maringá-Pr, Brazil.

AIM: Children's patterns of sugar consumption and dental health status have been associated to their mothers' patterns. As a liking for sweetness has been related to caries levels, this study was carried out to analyse the relationship between sweetness preference and caries experience in mother/child pairs. PARTICIPANTS AND METHODS: A cross-sectional survey was conducted on a sample of low socio-economic mothers and their 4-5-year-olds from Maringá-Pr, Brazil. Mothers' and children's preference for sugar was measured using the Sweet Preference Inventory. Their caries experience was assessed according to World Health Organization (WHO) guidelines. RESULTS: High levels of sweetness preference and caries experience were found in the sample studied. Although not strong, a significant correlation in patterns of sweetness preference (r=0.12, P<0.05) and caries experience (r=0.14, P<0.05) between mother/child pairs was identified. Among the social-demographic variables, only family income was statistically associated with the children's preference for sweetness (P<0.05). No significant association between sweetness preference and caries experience could be established. CONCLUSION: The findings of this study suggest that mothers may play an important role on the establishment of their children dietary preferences and patterns of dental health. Also, that the socio-economic status may influence children's preference for sugar.

Adult↗
PubMed2002

The relationship between the presence of periodontopathogenic bacteria in saliva and halitosis.

OBJECTIVE: To evaluate the association between the presence of periodontal pathogenic bacteria in saliva and halitosis in mouth air. DESIGN: Cross-sectional microbiological and clinical oral examination of adult patients. SUBJECTS: 101 adult patients (25 males, 76 females) who attended the Preventive Dentistry and Breath Odour Clinic of Kyushu Dental College. Their average age was 50.0+/-13.5 years old (mean +/- SD). SETTING: The subjects were classified into three groups: halitosis subjects with a probing depth (PD) > or = 4mm (P group), halitosis subjects without PD > or = 4mm (H group), and non-halitosis subjects without PD > or = 4mm (C group). METHODS: All subjects received a periodontal examination. Volatile sulphur compounds (VSC: hydrogen sulphide and methyl mercaptan) were measured using gas chromatography. The presence of Bacteroides forsythus, Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Prevotella intermedia in the saliva was detected by polymerase chain reaction. RESULTS AND CONCLUSION: The presence of B. forsythus, P. gingivalis and P. intermedia influenced the production of VSC. Specifically, the presence of B. forsythus in subjects with periodontitis was strongly correlated to the concentration of VSC in mouth air.

Actinobacillus Infections↗
PubMed2002

Prediction of survival and opportunistic infections in HIV-infected patients: a comparison of imputation methods of incomplete CD4 counts.

In evaluating the risk of mortality or development of opportunistic infections in HIV-infected patients, the number of CD4 lymphocyte cells per cubic millimetre of blood is widely recognized as one of the best available predictors of such future events. However, its usefulness is limited by the incompleteness and variability of such CD4 measurements during follow-up. Because of these limitations, analysis of such data requires the missing measurements to be 'filled in' or the patients without them to be excluded. We consider multiple imputation of CD4 values based partly on information from other health status measures such as haemoglobin, as well as on the event status of interest. These alternative health status measures are also considered as possible independent predictors of survival endpoints. Our work is motivated by a cohort of 1530 patients enrolled in two AIDS clinical trials. We compare our approach to other strategies such as basing evaluation of risk on baseline CD4, the last measured CD4 before an event, or a time-dependent covariate based on carrying the last CD4 value forward; we conclude with a strong recommendation for multiple imputation.

AIDS-Related Opportunistic Infections↗
PubMed2001

Competing approaches to analysis of failure times with competing risks.

For the analysis of time to event data in contraceptive studies when individuals are subject to competing causes for discontinuation, some authors have recently advocated the use of the cumulative incidence rate as a more appropriate measure to summarize data than the complement of the Kaplan-Meier estimate of discontinuation. The former method estimates the rate of discontinuation in the presence of competing causes, while the latter is a hypothetical rate that would be observed if discontinuations for the other reasons could not occur. The difference between the two methods of analysis is the continuous time equivalent of a debate that took place in the contraceptive literature in the 1960s, when several authors advocated the use of net (adjusted or single decrement life table rates) rates in preference to crude rates (multiple decrement life table rates). A small simulation study illustrates the interpretation of the two types of estimate - the complement of the Kaplan-Meier estimate corresponds to a hypothetical rate where discontinuations for other reasons did not occur, while the cumulative incidence gives systematically lower estimates. The Kaplan-Meier estimates are more appropriate when estimating the effectiveness of a contraceptive method, but the cumulative incidence estimates are more appropriate when making programmatic decisions regarding contraceptive methods. Other areas of application, such as cancer studies, may prefer to use the cumulative incidence estimates, but their use should be determined according to the application.

Computer Simulation↗