Identical independent sites for dye ligand on bovine serum albumin demonstrated by multivariate analysis.
(49/2223)
The most fundamental parameters concerning an interaction between a ligand and a protein are equilibrium constants and the number of binding sites. The Scatchard plot has for a long time been widely used to obtain those parameters. However, controversy in 1982-1983 over the reliability of this plot (the graphical estimation of the number of identical independent sites from the x-intercept) indicated that some methodologies other than the Scatchard plot are expected. Over the past decade, we have developed a method for applying multivariate analysis to the problem of determining spectral features of a ligand associated with a protein molecule. In principle, this method is based mainly on the computer-assisted adjustment of dissociation constants to an assumed reaction model. We discovered in this process that an n-parameter, introduced into an equation for calculating the amount of dye ligand bound to a protein, coincided with the number of identical independent sites, under a certain condition in principal factor analysis calculation. In this study, we established a new methodology for determining the number of identical independent sites using synthesized spectral series, and we then applied this method to a simple reaction system composed of bovine serum albumin (BSA) and bromocresol purple (BCP) anions. BSA was found to have two identical independent sites for BCP anions at pH 8.8. (+info)
Subtyping of juvenile idiopathic arthritis using latent class analysis. British Paediatric Rheumatology Group.
(50/2223)
OBJECTIVE: To use statistical techniques to identify underlying subtypes of juvenile idiopathic arthritis (JIA) that best explain the observed relationships of clinical and laboratory variables, and to compare the statistically derived subtypes with those defined by the International League of Associations for Rheumatology (ILAR) criteria and examine them for HLA associations. METHODS: Information on 572 patients diagnosed as having JIA was summarized by 10 clinical and laboratory categorical variables (age at onset, large joint involvement, small joint involvement, polyarthritis, symmetric arthritis, spinal pain, fever, psoriasis, antinuclear antibodies [ANA], and rheumatoid factor). Latent class analysis (LCA) was used to identify underlying ("latent") classes that explained the relationships among the observed variables. Statistical models incorporating 5-8 latent classes were applied to the data. RESULTS: The 7-class model was the most appropriate. Patterns of joint involvement and the presence of ANA were influential in determining latent classes. There was some correspondence between the latent classes and the ILAR categories, but they did not coincide completely. Significant differences between the latent classes were seen for 3 HLA haplotypes (DRB1*04-DQA1*03-DQB1*03, DRB1*13-DQA1*01-DQB1*06, and DRB1*08-DQA1*0401-DQB1*0402). CONCLUSION: LCA provides a novel approach to the task of identifying homogeneous subtypes within the umbrella of JIA. In further work, the identified latent classes will be examined for associations with other candidate genes and for differences in outcome. (+info)
Inter-ictal and post-ictal psychoses in frontal lobe epilepsy: a retrospective comparison with psychoses in temporal lobe epilepsy.
(51/2223)
There have been few studies of the psychopathology of patients with frontal lobe epilepsy (FLE). The majority of studies of both inter-ictal and post-ictal psychoses have strongly suggested the influence of temporal lobe disturbance on psychoses. Patients with organic brain damage or schizophrenia, however, sometimes show frontal lobe dysfunction. The purpose of this study was to better understand the effect, if any, of frontal lobe disturbance and seizure on psychopathology. Patients were divided into four groups based on epilepsy type and preceding seizures; 8 with FLE/inter-ictal psychosis, 3 with FLE/post-ictal psychosis, 29 with temporal lobe epilepsy (TLE)/inter-ictal psychosis, and 8 with TLE/post-ictal psychosis. Psychopathologic symptoms were retrospectively reviewed based on case notes, using a modified brief psychiatric rating scale (BPRS). Psychomotor excitement, hostility, suspiciousness, and hallucinatory behaviour were prominent features in all four groups. Six orthogonal factors were derived by factor analysis from the original data based on the 18 BPRS items. FLE patients with inter-ictal psychosis showed marked hebephrenic characteristics (i.e. emotional withdrawal and blunted effect). Our findings suggest that patients with FLE can exhibit various psychiatric symptoms. However, their psychotic symptoms, hebephrenic symptoms in particular, may often be overlooked. (+info)
Schizophrenia is not disappearing in south-west Scotland.
(52/2223)
BACKGROUND: Recent work has reported a decline in the incidence of schizophrenia, but it is unclear if these findings reflect a true decrease in its incidence or are an artefact arising from methodological difficulties. AIMS: To take account of these methodological difficulties and report service-based incidence rates for schizophrenia in Dumfries and Galloway in south-west Scotland for 1979-98. METHOD: Using both clinical diagnoses and diagnoses generated from the Operational Checklist for Psychotic Disorders (OPCRIT) computer algorithm for ICD-10 and DSM-IV schizophrenia, we measured change in the incidence rates over time. We used indirect standardisation techniques and Poisson models to measure the rate ratio linear trend. RESULTS: There was a monotonic and statistically significant decline in clinically diagnosed schizophrenia. The summary rate ratio linear trend was 0.77. However, using OPCRIT-generated ICD-10 and DSM-IV diagnoses, there was no significant difference over time. CONCLUSIONS: OPCRIT-generated consistent diagnoses revealed no significant fall in the incidence of schizophrenia. Changes in diagnostic practice have caused the declining rates of clinically diagnosed schizophrenia in Dumfries and Galloway. (+info)
Diagnosis of gastric cancer.
(53/2223)
A prospective comparison was made of the accuracy of different diagnostic methods for gastric cancer. The basis of the study was a consecutive series of 113 patients thought to have gastric pathology; cancer was the final diagnosis in 32. Endoscopy and radiology were the most accurate investigations, whereas biopsy, cytology, and clinical examination gave disappointing results. A wide range of clinical features and laboratory investigations were studied in all patients in an attempt to identify criteria suggestive of malignancy. Multifactorial computer analysis of these investigations failed to improve upon the radiological diagnosis. A systemic approach designed to make optimal use of limited endoscopic and histopathological resources in the diagnosis of gastric lesions is presented. (+info)
The development of an instrument to measure satisfaction with physical therapy.
(54/2223)
BACKGROUND AND PURPOSE: Patient satisfaction continues to receive attention as a measure of the outcome of physical therapy intervention. However, a great deal more attention has been paid to the topic outside of, rather than within, physical therapy. This article describes the development of an instrument that measures patient satisfaction among physical therapists' patients and clients. METHOD: A 26-item instrument designed to measure the domains of patient satisfaction among patients was developed by the authors in preparation for this study and field tested on patients from several sites comprising a large clinical operation. Descriptive statistics and estimates of reliability of measurements obtained with the instrument were computed. Reliability and validity were assessed. A total of 289 individuals completed the instrument. RESULTS: The coefficient for reliability (Cronbach alpha=.99) obtained for the instrument was clearly within a desired range. Different types of validity were established as well. CONCLUSION AND DISCUSSION: Instruments typically used by physical therapists to measure patient satisfaction have undergone little psychometric analysis. This instrument appears to meet the criteria required to make it a useful tool for measuring patient satisfaction. (+info)
Factor analysis of self-reported symptoms: does it identify a Gulf War syndrome?
(55/2223)
Active duty US Naval mobile construction battalion personnel (Seabees) were surveyed in 1994 for the presence of a variety of symptoms. Questions were drawn from the Hopkins Symptom Checklist and from a collection of symptoms either defining clinical depression or commonly reported by Persian Gulf War veterans. Of those surveyed, 524 were Gulf War veterans and 935 were nondeployed Gulf War-era veterans. Factor analysis applied to Gulf War veterans yielded five factors, three deriving from the Hopkins Symptom Checklist, one suggesting clinical depression, and one containing symptoms commonly reported by Gulf War veterans. Factor analysis applied to nondeployed veterans yielded five similar factors. Three of the factors yielded statistically significantly greater standardized factor scores for Gulf War veterans than for nondeployed veterans. Four of the factors resembled factors resulting from a previous analysis on a sample of similar Gulf War veterans. Gulf War veterans and nondeployed era veterans reported similar clusters of symptoms and illnesses. However, Gulf War veterans reported these same clusters with greater frequencies than did nondeployed veterans. The authors conclude that, in contrast to a previous report, factor analysis did not identify a unique Gulf War syndrome. (+info)
Development and application of a questionnaire for assessing parent satisfaction with care.
(56/2223)
OBJECTIVE: The development and application of a questionnaire that eventually could be used as a management tool and a means of promoting the quality of care provided in 'P. & A. Kyriakou' Children's Hospital. DESIGN: Parents' survey; during treatment of their children. SETTING: 'P. & A. Kyriakou' Children's Hospital, Athens, Greece. PARTICIPANTS: Sample of 240 parents. MAIN OUTCOME MEASURE: Parent satisfaction. RESULTS: The most important finding of the study, although normative statements cannot be made, appears to be signalling of low satisfaction with care. The general mean observed (45 on a scale of 100) is not close to the mean (76) derived from a systematic review of 221 satisfaction studies. Moreover, satisfaction appears to be very low (14/100) for the procedures of the hospital, low for the outpatient dimension (42/100) and rather satisfactory for the inpatient dimension (61/100). CONCLUSION: Data-based feedback as a management tool has been associated with improved organizational functioning. However, systematic use of this intervention within Greek hospitals has been limited. Therefore, the next phase of the project will be used as feedback to the Governing Board and the personnel of the hospital. Finally, a study will be planned to investigate the effects of implementing changes based on parents' ratings of staff performance. (+info)