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A simple method is described for fitting a rectangular hyperbola to force-velocity data derived from active muscle. The approach is based on three-dimensional regression analysis of the variables force, velocity and (force x velocity). The usage of the method is illustrated by practical applications. A pocket calculator is sufficient for the mathematical treatment.
A program, WRANL, is described for the analysis of immunoassays or bioassays which have a logistic dose-response relationship. Responses are transformed to logits and iterative weighted regression analysis is used to obtain log dose-logit response lines for all preparations compared in an assay. Potency estimates of preparations relative to the standard preparation are available for both unweighted and weighted regression analyses together with detailed analysis of variance, estimates of slope and other relevant parameters. The general comparisons of dose-response relationships produced by the program are a feature of particular interest. However, an option which suppresses the more general output is available if the program is to be used for analysis of a 'screening' assay comparing single dilutions or doses of test samples with a standard curve. Data input is designed to permit immediate running of the program by junior personnel. Data output is designed to facilitate record keeping.
A computer program is presented for non-linear regression analysis of radioimmunoassay data, which allows the determination of the binding parameters of monoclonal antibodies, i.e., affinity constant and number of available binding sites. The program is based on the median method and gives the values of the binding constants and their 95% confidence limits, without the necessity for their preliminary, approximate evaluation. The program may also be used to determine the binding constants for the interaction of receptors with labelled ligands.
The aim of this study was to determine the factors that influence the prognosis of hypertensive putaminal hemorrhage. We investigated the outcome of the activity of daily living (ADL 1: full recovery at social life, 2: self cared, 3: required partial care at home, 4: remained bedridden, 5: vegetative state, 6: dead) one year after the onset of putaminal hemorrhage in comparison with initial data obtained on the day when it occurred. The following parameters were assessed: sex, age, side of hematoma, classification of computed tomography (CT) findings, neurological grade, degree of muscle power, hematoma volume, treatment, past history of cerebrovascular disease, and laboratory data. In 67 patients with putaminal hemorrhage, the relationships among these parameters were examined using Spearman's rank correlation analysis. Additionally, in 55 patients (24 male and 31 female) with complete data from the day of onset, multiple regression analysis was performed. The data of muscle power were handled by the quantification method. The result of Spearman's rank correlation coefficient indicated that the outcome had a positive correlation with age (correlation coefficient = 0.375), CT classification (0.595), neurological grade (0.714), hematoma volume (0.689), a past history of cerebrovascular disease (0.475), the white blood cell count (0.541), and the lactate dehydrogenase level (0.347). The outcome had a negative correlation with muscle power (-0.579) and the cholinesterase (-0.340).(ABSTRACT TRUNCATED AT 250 WORDS)
The underlying logic of retrospective research in speech pathology is examined critically. This research model focuses on differences among discrete groups. Regression analysis concepts are suggested as a tool to evaluate the practical or theoretical importance of statistically significant differences obtained in retrospective research. This type of analysis focuses on the degree to which a criterion measure can be predicted from knowledge of group classification, rather than on differences among means.
For the purpose of evaluating the significance of obesity as a risk factor toward various chronic geriatric diseases, a multiple regression analysis was performed on the annual physical checkup data of UOEH employees in 1991. The following results were obtained. (1) The average obesity index of the UOEH employees showed a progressive and significant increase in the 10 years from 1981 to 1991. (2) A close relation between the obesity index and serum GPT was recognized by elevation of the standard partial regression coefficients of serum GPT to obesity index and that of the obesity index to serum GPT when the data from all 1591 UOEH employees were analysed in one group. This finding was derived from a significant contribution of obesity to the liver dysfunction in the young male obese population under 30 years of age. (3) Systolic blood pressure was related to age rather than the obesity index, indicating that the development of hypertension is more closely related to aging than obesity. (4) No significant relation was found between the serum total cholesterol level and the obesity index in any group analysed. From the above findings, it can be suggested that the obesity in young male employees is more closely related to liver dysfunction than other abnormalities.
Bladder neck position, as determined by preoperative and postoperative resting and straining lateral bead-chain cystourethrograms, was analyzed by logistic regression analysis in 94 women undergoing 98 operations for genuine stress incontinence. A total of 384 roentgenograms were analyzed in an attempt to build a model that would predict the likelihood of surgical success in a given patient based on the preoperative films and explain a successful surgical outcome based on the characteristics of the postoperative films. The most important predictors of success were the number of previous incontinence operations, a large distance between the bladder neck and the pubic symphysis at rest, and increased mobility of the bladder neck before surgery. Successful surgery appeared to be related most closely to decreasing mobility of a previously hypermobile bladder neck.
We conducted a multiple regression analysis on the surgical results (minimum follow-up of 5 years) of 55 patients who underwent expansive open-door laminoplasty (open-door ELAP) for cervical myelopathy due to ossification of the posterior longitudinal ligament (OPLL) in order to determine statistically the impact of factors influencing the results. Duration of myelopathy was found to be a significant factor indicating poor results, while progression of ossification and age at the time of surgery were significant factors indicating deterioration. Three other factors (preoperative severity of myelopathy, degree of spinal canal expansion and changes of the curve indices before and after surgery) did not have a significant influence on the results. To improve the surgical results, it is thus essential to operate on patients as soon as they develop symptoms of myelopathy. There exists a certain limitation in posterior decompression for OPLL including open-door ELAP until prevention of the progression of ossification becomes possible.
We show that the generalized F family is a useful tool for regression analysis with censored survival data. We discuss maximum likelihood estimation and give asymptotic procedures for calculating confidence intervals, tests of significance for the parameters, life expectancy, quantiles and survival rates. Survival data on 704 ovarian carcinoma patients serve to demonstrate the utility of the model.
Fourteen cytologic features seen in fine needle aspirates of papillary carcinoma of the thyroid were subjected to a step-wise logistic regression analysis to determine which are predictive of papillary carcinoma. The study cases included 38 histologically proven papillary carcinomas and 54 other palpable thyroid nodules. The three most important variables in making the prediction of papillary carcinoma were intranuclear inclusions, papillary structures without vessels and cells with metaplastic cytoplasm.
The influence of age on the prevalence of individual clinical manifestations of systemic lupus erythematosus (SLE) has not been adequately distinguished from racial or gender influences. Therefore, we examined variations in the clinical manifestations of SLE with age in a group of 361 patients. Multivariate regression techniques, including logistic regression and analysis of covariance, were used to identify clinical features associated with age, while controlling for important confounding factors, including race, gender, duration of followup, and treatment effects. Lymphopenia was found more frequently with increasing age, while malar rash, seizures, false-positive VDRL, thrombocytopenia (in whites), proteinuria (0.5-3.5 g/day), elevated antidouble stranded DNA antibodies, and hypocomplementemia were found less frequently. No age relationship was found for the prevalence of 16 of 24 clinical features examined, including the important disease manifestations of arthritis, serositis, psychosis, nephrotic-range proteinuria, renal failure, autoimmune hemolytic anemia, and leukopenia. The use of regression analysis allows the recognition of similarities and differences in cumulative clinical features of SLE due to age in isolation from the effects of other demographic factors.
We consider a mixture model approach to the regression analysis of competing-risks data. Attention is focused on inference concerning the effects of factors on both the probability of occurrence and the hazard rate conditional on each of the failure types. These two quantities are specified in the mixture model using the logistic model and the proportional hazards model, respectively. We propose a semi-parametric mixture method to estimate the logistic and regression coefficients jointly, whereby the component-baseline hazard functions are completely unspecified. Estimation is based on maximum likelihood on the basis of the full likelihood, implemented via an expectation-conditional maximization (ECM) algorithm. Simulation studies are performed to compare the performance of the proposed semi-parametric method with a fully parametric mixture approach. The results show that when the component-baseline hazard is monotonic increasing, the semi-parametric and fully parametric mixture approaches are comparable for mildly and moderately censored samples. When the component-baseline hazard is not monotonic increasing, the semi-parametric method consistently provides less biased estimates than a fully parametric approach and is comparable in efficiency in the estimation of the parameters for all levels of censoring. The methods are illustrated using a real data set of prostate cancer patients treated with different dosages of the drug diethylstilbestrol.
One hundred and forty-seven patients undergoing minor orthopaedic surgery were studied prospectively by logistic regression analysis to determine the association of independent fixed patient factors with the incidence of postoperative sickness (nausea, retching or vomiting). Gender, history of previous postoperative sickness, postoperative opioids and interaction between gender and previous history of sickness were significant independent factors for postoperative sickness; history of motion sickness was weakly associated. The probability of postoperative sickness in the first 24 h after surgery may be estimated from the equation: logit postoperative sickness = -5.03+2.24(postoperative opioids) +3.97 (previous sickness history) +2.4 (gender) +0.78 (motion sickness) -3.2 (gender x previous sickness history). (Log likelihood ratio test for 5 degrees of freedom for the coefficients, chi-square = 53.5 (P < 0.001).) It is suggested that the calculated probability for sickness may be a useful addition for balancing patient treatment groups and allowing between-study comparisons.
This study was conducted to determine true ileal AA digestibility coefficients and the endogenous AA outputs associated with barley samples for growing-finishing pigs using the regression analysis technique with dual digestibility markers. Six barrows, with 30.5 and 58.6 kg average initial and final BW, were fitted with a simple T-cannula at the distal ileum and fed six barley-based diets at close to ad libitum feed intake according to a 6 x 6 Latin square design. The six diets contained 97% of six barley samples varying from low to high in CP and AA contents (8.5, 9.2, 9.8, 11.5, 12.6, and 15.6% CP, respectively, on DM basis). The dietary NDF content ranged from 16.8 to 23.8% on DM basis. Chromic oxide (Cr2O3) and acid-insoluble ash (AIA) were used as digestibility markers. Each experimental period lasted 7 d. Ileal digesta were collected, at 2-h intervals, for a total of 24 h during d 6 and 7. There were linear relationships (P < 0.01) between dietary contents of apparent ileally digestible and total CP and AA as determined by using either Cr2O3 or AIA as a digestibility marker. The use of Cr2O3 vs AIA affected (P < 0.01) the determination of true ileal AA digestibility coefficients and the endogenous CP and AA outputs. However, there were no differences (P > 0.01) in the true ileal AA digestibility coefficients in barley samples between this study and the average values reported in the literature. The endogenous CP and AA outputs determined in this study were higher (P < 0.01) than reported values (35.1+/-3.0 vs 14.7+/-1.1 g CP/kg DMI). It is concluded that dual digestibility markers should be used to measure true ileal AA digestibility coefficients and endogenous AA outputs when dietary fiber content is high and the ileal digesta is collected through a simple T-cannula in the pig. True rather than apparent ileal AA digestibility coefficients determined in barley samples should be used in diet formulation for swine. The gastrointestinal endogenous AA secretion, recycling, and output losses are important in whole-body AA utilization and homeostasis, especially when fiber-enriched diets are fed to growing-finishing pigs.
The relationship between phonating and the multiview videofluoroscopic measurement of velopharyngeal range was studied by multifactorial stepwise regression analysis using an electronic computer. The results showed: (1) The degree of velopharyngeal closure is the most important factor during phonating; (2) There are close correlations between the degree of clearness of speech, the raising angle of soft palate and the contracture ability of lateral pharyngeal walls; (3) There are close relations between the length of soft palate and the degree of velopharyngeal closure; (4) There are also close correlations between the elongation of soft palate, the raising angle of soft palate, the contracture ability of lateral pharyngeal walls and the degree of velopharyngeal closure during phonating.
We have been investigating the mathematical nature of intercancer linkage that underlies the mutual regulation of cancer risks between any 2 tumors in their variations in time and space. Applications of both sequential regression test and topological manipulation of age-adjusted incidence rate (AAIR) data set enabled us to prepare the oncogene (Onc) activation profile and the tumor suppressor gene (TSG) inactivation profile for each tumor. The purpose of this study was to investigate the relation between the changes of 2 cancer gene profiles and the sex discrimination of cancer risk in 7 human neoplasias. Results obtained are as follows: i) The sex discrimination of cancer risk could better be defined by the use of log-transformed AAIR data rather than of untransformed AAIR data. ii) The sex discrimination of cancer risk, as calculated with the AAIR data of 47 population units of the world, is as follows: a) breast cancer (Br), M:F=1:120.2; b) thyroid cancer (Thy), M:F=1:2. 64; c) colon cancer (Co), M:F=1.18:1; d) liver cancer (Li), M:F=2. 63:1; e) lung cancer (Lu), M:F=3.66:1; f) esophageal cancer (Eso), M:F=3.68:1; g) laryngeal cancer (Lar), M:F=7.26:1. iii) Female-dominant cancers were associated with inversion (Br) or defectiveness (Thy) of male oncogene profile, whereas male-dominant cancers were associated with inversion (Lar) or defectiveness (Li, Lu and Eso) of female Onc profiles. Sex-indifferent cancer, Co, was distinguished from other tumors by the emergence of defectiveness in the TSG profiles of both sexes. TSG defectiveness was also detectable in female (Br, Thy) and bisexual (Lu) tumors. iv) The Onc vs TSG interaction, as assessed in terms of r value of the reciprocal regression analysis, was increasing in its positivity rate from the top of the female-dominant family (Br) through the sex-indifferent tumor (Co) to the bottom of the male-dominant family (Lar). In conclusion, the emergence of sex discrimination of cancer risk was positively correlated to the extent of integrity of oncogene activation in the dominant gender relative to the recessive gender. Findings with 6 sex-discriminant tumors are discussed in their relevancy to tumorigenesis from the point of view of endocrinological epidemiology.
For the purpose of evaluating the significance of obesity in a young population as a risk factor toward various chronic diseases, a multiple regression analysis was performed on the data from the annual physical checkup of medical students of UOEH in 1991. The following results were obtained. (1) The average obesity index of the students showed a progressive and significant increase in the past 13 years from 1979 to 1991. (2) A close correlation between the obesity index and serum GPT was recognized by elevation of the standard partial regression coefficient of serum GPT to obesity index and that of obesity index to serum GPT when the data from all 617 students was analysed in one group. This finding was intensified in 142 obese students with an obesity index of over 10%, but it was not seen in the remaining non-obese students. (3) The correlation between the obesity index and serum GPT was found solely in the group of students with constant obesity; i.e., whose obesity index was always more than 10% during a maximum of 9 years in the past. (4) Systolic blood pressure was related to the red blood cell count rather than to the obesity index in this young population. (5) No particularly close correlation to serum cholesterol was found with any of 10 representative items examined in this physical checkup, including the obesity index, indicating that the other factors should be related to serum cholesterol levels. From the above findings, it can be concluded that constant obesity in students is related to liver dysfunction, probably due to fatty liver frequently seen in the precise examination of these individuals.
A new approach has been developed to evaluate the adequacy of HFRS clinical diagnosis, by using regression analysis of large selections. The HFRS morbidity rate and the antibody prevalence rate in man were viewed as a function and an argument of the function, respectively. An empiric model for one of the active HFRS endemic area (Saratov Province), characterizing the correlation between the immunity and morbidity rates has been elaborated. It calculates the theoretical morbidity level that corresponds to determine an immune portion of the population in each administrative area. The theoretical (counted) values were compared to the annually registered morbidity rates; their similarity has been estimated. Estimation of the adequacy of HFRS diagnosis in the examined region could have been admitted as satisfactory. However, various faults in the clinical identification of HFRS cases were found to occur in 14 of 44 districts of this region. Hyperdiagnosis was made in the most active HFRS natural foci (broad-leaved forests), but in the endemic areas being characterizes by moderate or low activity (forest-steppe and steppe districts). The results of the authors' calculations were shown to be generally in agreement with the data from the Regional Epidemiological Service reports which confirmed the adequacy of the proposed material.