Design and data analysis case-controlled study in clinical research.

Clinicians during their training period and practice are often called upon to conduct studies to explore the association between certain exposures and disease states or interventions and outcomes. More often they need to interpret the results of research data published in the medical literature. Case-control studies are one of the most frequently used study designs for these purposes. This paper explains basic features of case control studies, rationality behind applying case control design with appropriate examples and limitations of this design. Analysis of sensitivity and specificity along with template to calculate various ratios are explained with user friendly tables and calculations in this article. The interpretation of some of the laboratory results requires sound knowledge of the various risk ratios and positive or negative predictive values for correct identification for unbiased analysis. A major advantage of case-control study is that they are small and retrospective and so they are economical than cohort studies and randomized controlled trials.

Relevance of Vrksayurveda and other traditional methods for organic production of nursery seedlings of useful plants.

Plant propagation is critical to augment the resource and has been the main concern for farmers and planters through history. India has evolved the science of Vrksayurveda to address the above issue. An effort is made here to review Vrksayurveda literature related to nursery techniques. Different libraries were visited and relevant review material obtained by hand search and from databases. Interaction with Sanskrit scholars and eminent scientists working in the field of Vrksayurveda, as well as the efforts of the authors of this paper, helped in the selection of pertinent literature. In the absence of original texts, authentic translations of the publications were referred. A conscious decision was made to limit the search to the fields of seed storage, pretreatment and nutrition of seedlings. To have a comparative account recent trends and literature on nursery technology were also examined. This was supplemented by interviews with traditional organic farmers. Our survey revealed that the time period of the literature pertaining to Vrksayurveda ranges from BCE 1200 to the present times. The subject has evolved from morphological descriptions and uses of plants, in texts such as Rgveda and Atharvaveda, to treatises dedicated solely to the art of growing plants like Krsi-Parasara and Vrksayurveda. It is also evident that there were important periods when more works appeared across subjects such as water divining, soil types, seed collection and storage, propagation, germination and sprouting, watering regimen, pest, and disease control. The review revealed that valuable information pertaining to nursery techniques is available in Vrksayurveda, which can be used in the development of nursery protocol. This will not only help in effective organic nursery management, but also ensure the health and livelihood security of the communities involved and effective waste management.

Evaluation of the therapeutic community treatment model in Thailand: policy implications for compulsory and prison-based treatment.

This study, conducted in 2005 to 2007, presents results that are based on a proscriptive cohort design. The sample consisted of 769 residents in 22 drug user treatment programs who stayed in treatment for at least 30 days to one year; 510 former residents (66%) from 21 programs (95%) were interviewed again at a 6-month post-treatment follow-up assessment. A majority of the participants were male, lived with family or relatives, had completed only primary school, and had a full-time or a part-time job prior to entering treatment. The participating therapeutic community (TC) programs were a mixture of volunteer, compulsory-probation, and prison-based programs. In-person interview data and urine testing showed that the self-reported drug use prevalence rates are reliable. The results show large positive treatment effects on 30-day and 6-month illegal drug use and small to medium effects on the severity of alcohol use and related problems. A multilevel regression analysis suggests that residents' reduced stigma, adaptation of the TC model, and frequency of alcohol and drug use-related consequences partially predict treatment success. Study limitations and policy implications are discussed.

Design and data analysis 1 study design.

This article is intended to give the reader guidance in evaluating different study designs used in medical research for better scientific quality, reliability and validity of their research. This article explains three main types of study designs with understanding examples. Care and caution with skills and experience needed to design suitable studies and appropriate design coupled with reliable sampling techniques and appropriate statistical analysis, supported by clear objectives with decent communication of the findings, are essential for good research.

Design, data analysis and sampling techniques for clinical research.

Statistical analysis is an essential technique that enables a medical research practitioner to draw meaningful inference from their data analysis. Improper application of study design and data analysis may render insufficient and improper results and conclusion. Converting a medical problem into a statistical hypothesis with appropriate methodological and logical design and then back-translating the statistical results into relevant medical knowledge is a real challenge. This article explains various sampling methods that can be appropriately used in medical research with different scenarios and challenges.

Therapeutic community drug treatment success in Peru: a follow-up outcome study.

BACKGROUND: The purpose of this study was to assess the impact of drug abuse treatment in Peru that used the therapeutic community (TC) model. Program directors and several staff members from all study treatment facilities received two to eight weeks of in-country training on how to implement the TC treatment model prior to the follow-up study. METHODS: This outcome study involved 33 TC treatment facilities and 509 former clients in Lima and other cities in five providences across Peru. A retrospective pre-test (RPT) follow-up design was employed in which 30-day use of illegal drugs and alcohol to intoxication was measured at baseline retrospectively, at the same time of the six-month follow-up. In-person interview data were collected from directors of 73 percent of the eligible TC organizations in January and February 2003 and from former 58 percent of the eligible TC former clients between October 2003 and October 2004. Drug testing was conducted on a small sample of former clients to increase the accuracy of the self-reported drug use data. RESULTS: Medium to large positive treatment effects were found when comparing 30-day illegal drug and alcohol use to intoxication before and six months after receiving treatment. As a supplemental analysis, we assumed the 42 percent of the former clients who were not interviewed at the six month assessment had returned to drugs. These results showed medium treatment effects as well. Hierarchical Generalized Linear Modeling (HGLM) results showed higher implementation fidelity, less stigma after leaving treatment, and older clients, singly or in combination are key predictors of treatment success. CONCLUSION: This study found that former clients of drug and alcohol treatment in facilities using the TC model reported substantial positive change in use of illegal drugs and alcohol to intoxication at a six-month follow-up. The unique contribution of this study is that the results also suggest attention should be placed on the importance of implementing the TC drug abuse treatment model with fidelity. Further, the results strongly suggest that TC drug abuse treatment programs should incorporate follow-up activities that attempt to neutralize community negative reactions (perceived stigma) independent of other factors.

DSCAM is a netrin receptor that collaborates with DCC in mediating turning responses to netrin-1.

During nervous system development, spinal commissural axons project toward and across the ventral midline. They are guided in part by netrin-1, made by midline cells, which attracts the axons by activating the netrin receptor DCC. However, previous studies suggest that additional receptor components are required. Here, we report that the Down's syndrome Cell Adhesion Molecule (DSCAM), a candidate gene implicated in the mental retardation phenotype of Down's syndrome, is expressed on spinal commissural axons, binds netrin-1, and is necessary for commissural axons to grow toward and across the midline. DSCAM and DCC can each mediate a turning response of these neurons to netrin-1. Similarly, Xenopus spinal neurons exogenously expressing DSCAM can be attracted by netrin-1 independently of DCC. These results show that DSCAM is a receptor that can mediate turning responses to netrin-1 and support a key role for netrin/DSCAM signaling in commissural axon guidance in vertebrates.

Drug abuse treatment training in Peru. A social policy experiment.

A social policy experiment is presented that was conducted from 1997 to 2000 in a setting with a high level of readiness for implementing a randomized experiment of therapeutic community (TC) drug treatment training in Peru. Seventy-six drug abuse treatment organizations were randomly assigned into three groups, and data were collected at multiple assessment periods. Staff and directors in organizations assigned to the training groups participated in either 6-week basic training or 8-week basic plus booster training sessions, which were theoretically grounded. Small- to medium-size positive effects were found on increased staff empowerment to use actual tools and principles from the training; medium and large positive effects were found on the implementation of TC methods with fidelity after the training. A follow-up with the funding and training organizations 1 year later showed use of the evaluation results in decision making in both organizations.