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This paper describes a model which makes allowance for unequal follow up times in estimating the risk as a function of risk factors. It is the exponential model with a hazard which is also an exponential function of risk factors. Computing methods and an extension of the model are given.
MOTIVATION: To find a correlation between the activities and structures of molecules is one of the most important subjects for molecular evaluation study. Traditional quantitative structure-activity relationship (QSAR) methodologies represent those attempts using physicochemical descriptors. Creating a new molecular description factor based on the results of a computational docking study will add new dimensions to molecular evaluation. RESULTS: We propose a new molecular description factor analysis system called the Comparative Molecular Interaction Profile Analysis (CoMIPA) system in which the AutoDock program is used for docking evaluation of small molecule compound-protein complexes. Interaction energies are calculated, and the data sets obtained are called interaction profiles (IPFs). Using the IPF as a scoring indicator, the system could be a powerful tool to cluster the interacting properties between small molecules and bio macromolecules such as ligand-receptor bindings. Further development of the system will enable us to predict the adverse effects of a drug candidate.
This cross-sectional study revealed a prevalence of reduced calcaneal bone density in a population of 49 chronic continuing care patients with restricted mobility. Calcaneal bone density was measured using the Compton gamma ray scattering technique, which permits examination of trabecular bone. Predicted densities were determined from the ages and weights of the subjects. Descriptive factors such as gender, diagnosis, duration of the condition, and muscle tone were correlated with bone density. Twenty-eight patients (57%) had indications of reduced calcaneal bone density. None of the descriptive factors was associated with the variability in bone density ratio (forward stepwise regression analysis, p = NS). The reduced calcaneal density found in these patients with restricted mobility is probably a result of their not bearing weight and the inevitable severe reduction in their physical activity.
A series of 198 patients with chronic pain of diverse etiology was carefully analyzed for epidemiologic and descriptive factors which might influence the response to transcutaneous stimulation. The overall series included 12 1/2% with long-term success, and 68% with partial or short-term relief. There were no consistent specific diagnoses, or epidemiologic or descriptive factors that made good results from stimulation predictable. Stimulation of the painful area itself was not always necessary for pain relief. Favorable responses to transcutaneous stimulation were usually correlated with the continued existence of significant sensory input from the painful region. The authors conclude that transcutaneous stimulation is a valuable therapeutic modality for some patients with chronic pain.
A model for studying transfer of delayed-type sensitivity to mice with cellfree materials is described. The results with a particulate antigen (Candida) and 4 soluble protein antigens (PPD, ferritin, cytochrome c, and horseradish peroxidase) suggest that the phenomenon is antigen specific. Identical preparations from the spleens of insensitive donors were not active. This murine model should facilitate characterization of the immunologic and chemical properties of transfer factor.
Twenty-four apparently unrelated Italian patients with autosomal dominant type 1 von Willebrand disease (VWD) and a clear autosomal pattern of inheritance of bleeding symptoms were screened for the C1149R and C1130F mutations. None of the patients had the C1149R mutation; three patients and four affected relatives were heterozygous for the C1130F mutation. The mutation appeared to be linked to a single haplotype, defined by five genetic markers [variable number tandem repeat (VNTR) I and II in intron 40, RsaI in exons 13 and 18 and HphI in exon 28], suggesting a founder effect. The patients responded well to desmopressin infusion. The C1130F mutation might have a dominant negative effect on the secretion of the normal protein that desmopressin would appear to overcome.
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Dilute whole blood clots were prepared by addition of thrombin to blood diluted 1:10 in phosphate buffer. The pH of this buffer was 7.4 and the ionic strength was 0.084. Though the ionic strength was low, there was no hemolysis of red corpuscles due to the contribution to the osmotic gradient by plasma salts and proteins. In the standard assay the clot was formed by addition of thrombin at 4 degrees C then incubated at 37 degrees C. Retraction and lysis of these clots were inhibited by removal of platelets and by increasing concentrations of purified thrombin. Retraction and lysis were also inhibited by inactivation of any one of the following factors: gammaM globulin, complement components C4 and 3, and (in the case of lysis) plasminogen. Evidence that some of the above serum factors were adsorbed to the platelet membrane was obtained by aggregation of washed platelets by antisera to these factors (i.e. fibrinogen, gammaM, and C4 or C3). These platelets were not aggregated by antisera to other serum proteins (by albumin, transferrin, gammaG globulin). These and other studies suggested that platelets, thrombin, fibrinogen, gammaM globulin (cold agglutinin), complement components, and plasminogen influenced and facilitated retraction and lysis of clots. These studies also suggested that platelets and some of these factors were physically associated. Because of this physical association, and because of the fact that clot retraction is associated with aggregation and retraction of platelets, we extended the above observations to include a study of the effect of these same serum factors on serum-induced aggregation and retraction of washed platelets. (Other terms which have been in use in the past to describe serum-induced platelet aggregation and retraction have included those such as platelet "fusion" and "viscous metamorphosis," neither of which fully described the phenomena.)Platelet aggregation and retraction induced by serum was markedly accelerated by addition of increasing concentrations of thrombin and (or) cold agglutinin. Hirudin and antisera to gammaM globulin inhibited seruminduced aggregation and retraction of platelets. Reconstitution of inactivated serum with purified C4, 3, and 5 and thrombin restored its capacity to induce aggregation and retraction of platelets.Therefore, we postulated that platelet aggregation and retraction were necessary for clot retraction and that platelet aggregation and clot retraction facilitated clot lysis. More specifically we postulated that thrombin, in addition to catalyzing clot formation, also modified the platelet membrane such that gammaM globulin (cold agglutinin) and complement components can act on the platelet membrane leading to (a) aggregation and retraction of the platelets, (b) retraction of the clot, and (c) to the activation of plasminogen either on the surface of the platelet by C8i and (or) by release of platelet activators of plasminogen.
This article describes the first phase of a study that was designed to gain an understanding of hazardous waste workers' attitudes and beliefs about the use of respiratory protective equipment. Exploratory, open-ended interviews were conducted among 28 respirator users at a US Department of Energy facility. Subjects were asked to describe their knowledge, attitudes, and beliefs about their risks to hazards at their worksites and to discuss their use of respiratory protective equipment. A detailed content analysis of the interviews resulted in the generation of a taxonomy of issues and concerns which fell into three general categories: 1) Knowledge, Beliefs, and Attitudes, 2) Physical and Psychological Effects, and 3) External Influences. Knowledge, Beliefs, and Attitudes included Training, Fit Testing, Medical Clearance, Work Exposures, Respirator Use, and Vulnerability to Disease. Physical and Psychological Effects included Somatic/Health Effects, Personal Comfort, Visual Effects, Fatigue, Communication, and Anxiety. External Influences included Structural Environment, Quality and Availability of Equipment, Other PPEs, Co-Worker Influence, Supervisor Influence, and Organizational Culture. The findings from this study have important implications to training and education programs. Effective respiratory protection programs depend on a knowledge of the factors that affect workers' use of equipment. This study suggests that efforts to assure equipment comfort and fit, to assist workers who see and hear less well as a result of their equipment, and to develop strategies to allay worker anxiety when wearing equipment should all be components of a program. An organizational culture that supports and abets the appropriate use of equipment is also a critical element in a successful program.
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OBJECTIVE: To provide a description and identify risk factors for functional disability in early rheumatoid arthritis (RA). METHODS: A cohort of 337 patients with early RA with disease duration under 5 years was constituted in 2 areas in France and The Netherlands. Examination included the Ritchie index, the presence of nodes and other extraarticular manifestations, and the erythrocyte sedimentation rate (ESR). The Health Assessment Questionnaire, adapted and validated in the French and Dutch languages, was used to assess functional disability. RESULTS: The results allowed for the cross sectional description of a marked early functional disability, with a score of 1 (adjusted for disease activity variables) from the first year of the disease. Functional disability was increasing nonlinearly with the disease duration in a quadratic model. Disease activity variables, namely ESR and Ritchie index, were identified as other important components of functional disability. CONCLUSION: Consequences for the early management of RA are underlined.
The 5-factor approach (FFA) to personality description has been represented as a comprehensive and compelling rubric for assessment. In this article, various misgivings about the FFA are delineated. The algorithmic method of factor analysis may not provide dimensions that are incisive. The "discovery" of the five factors may be influenced by unrecognized constraints on the variable sets analyzed. Lexical analyses are based on questionable conceptual and methodological assumptions, and have achieved uncertain results. The questionnaire version of the FFA has not demonstrated the special merits and sufficiencies of the five factors settled upon. Serious uncertainties have arisen in regard to the claimed 5-factor structure and the substantive meanings of the factors. Some implications of these problems are drawn.
This paper critically reviews the values and perspectives evident in the formulation of the category of Somatoform Disorders in the widely used Diagnostic and Statistical Manual-IV (DSM-IV) [1] of the American Psychiatric Association. The conflict of values evident in the DSM Committee's elimination of causal issues and including only descriptive criteria in the final classification is emphasized. In this approach, causation was dismissed and only a description of popular clinical entities was allowed. It becomes clear that there was a conflict between causal and descriptive factors in the formation of the current classifications. The dubious logic and the inconsistencies that underlie the linking of the various diagnoses under the Somatoform Disorder (SD) rubric is presented. A heuristic model of the interaction of psychological and somatic variables is described. These variables act in a causal fashion and should be the basis for any nosological system of the SDs. There is ample evidence to support the importance of causal factors in the development of SDs, and the current descriptive nomenclature does not do justice to the rapidly growing field of Psychosomatic Medicine. A new scheme is proposed, using the presence or absence of stress as the connecting link for the diagnoses offered. The old nosology enhances the perpetuation of the mind-body dichotomy. Stress, representing the way in which the environment impinges on the human being, allows the mind-body dichotomy to be eliminated. The preferred synthesis of mind-body interaction as partly the result of experience in the environment becomes the basis for the new nosology.
A number of hypotheses were generated predicting the relationship between the Child Abuse Potential (CAP) Inventory and factors on the Sixteen Personality Factor (16PF) questionnaire. As expected, positive relationships were found between abuse and apprehension, tension, and anxiety, while a negative relationship was observed between abuse and stability. The 16PF factors of apprehension, tension, anxiety and stability, which had the strongest relationship with abuse, are factors descriptive of neuroticism. A regression and discriminant analysis, however, indicated these factors alone were not sufficient to accurately describe and predict abuse.
BACKGROUND: Utilization of medical care services has been used as a surrogate for outcome of patient compliance with treatment regimens. Antihypertensive treatment status and selection of drug agents may influence medical utilization. The purpose of this study was to determine the association between medically untreated hypertension and treated hypertension according to class of antihypertensive agent with the rate of hospitalization. METHODS: This is a retrospective, observational study on adult hypertensive patients based on claim data from a network-model HMO. The 12,548 patients were identified by ICD-9-CM hypertensive codes over a 3-year period. The hospital admission rate was the outcome measurement. The exploratory variables included antihypertensive treatment status and drug class. Patients' age, gender, and coexisting medical conditions were treated as confounding factors. Descriptive analyses and multivariate regression analyses were performed. RESULTS: Coexisting medical conditions were significant factors in hospital admission rates. Compared with diuretic treatment, there were no differences in hospital admission rates among hypertensive patients treated with an angiotensin II antagonist or angiotensin-converting enzyme inhibitor. Untreated patients or those treated with beta-blockers or calcium channel blockers experienced higher hospitalization rates (95% CI, 1.25-1.90, 1.03-1.44, and 1.08-1.46, respectively). CONCLUSIONS: Compared with the major antihypertensive agents or no therapy for hypertension, diuretic or angiotensin-converting enzyme inhibitor therapy may result in a reduced rate of hospital utilization.
Experimental measurements in a water phantom were made for a new shielded plastic Fletcher applicator. A dose calculation algorithm which allows the description of asymmetrically shielded source containers is presented. The traditional primary plus build-up factor description of the dose in a homogeneous volume is corrected by using effective attenuation coefficients measured in a water phantom for all the source-shield-container materials. Comparison of the theoretical results to the experimental data shows excellent agreement.
The Minnesota Developmental Programming System Behavioral Scales, Alternate Form C, designed to assess adaptive behavior of profoundly developmentally disabled individuals, was evaluated using data from 3,487 individuals. Relative difficulty within each of four 20-item subscales (Gross Motor, Eating, Environmental Integration, and Language/Communication) deviated slightly from the original instrument description. Factor analyses with orthogonal rotation revealed six factors with high loadings on, respectively: (a) difficult items from all subscales, (b) items from both Gross Motor and Eating subscales, (c) items from both Environmental Integration and Language/Communication subscales, and (d) items within each individual subscale except Language/Communication. Oblique rotation suggested two factors for each subscale, one loading on easier items and one loading on more difficult items. Factor patterns after oblique rotation were similar for four age groups ranging from young children (less than 5 years) to adults (over 30 years). Factor analyses of items within each subscale showed predominance of a single factor and no strong evidence of subscale multidimensionality. These results, in large part, confirmed the original Form C description.