A growth curve approach to the measurement of change.

The measurement of individual change is approached from the standpoint of individual time paths and statistical models for individual change. The authors consider both statistical and psychometric properties of measures of individual change and examine measures of change for data with more than 2 observations on each individual. It is noted that many conclusions conflict with previous behavioral science literature. (63 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparative study of synchronised and conventional culture methods on the micronucleus dose-response curve

The involvement of GABAA and GABAB receptors in neural mechanisms responsible for the production of theta rhythms in hippocampal formation (HPC) slices is addressed in the present study. In a number of papers published in the last decade, we have demonstrated that theta-like activity can be successfully recorded in the limbic cortex maintained in vitro when the cholinergic agonists, acetylcholine, carbachol or muscarine, were added to the bath. Recently, we have also shown a strong GABAA modulation of the cholinergic-induced in vitro theta-like activity. This study presents a report of the first demonstration of in vitro theta-like field responses induced a consequence of simultaneously inhibiting hippocampal GABAA and GABAB receptors. HPC slices (350 microns) were maintained in a gas-liquid interface chamber (35 degrees C). Theta-like activity was induced in the presence of bath perfusion of bicuculline (GABAA antagonist) and 2-hydroxysaclophen (GABAB antagonist). This in vitro induced field response was antagonized both by muscimol (GABAA agonist) and baclophen (GABAB agonist). In addition, the experiments presented here revealed that bicuculline/2-hydroxysaclophen-induced in vitro theta-like activity also had a strong cholinergic M1 involvement: it was abolished by hemicholinium-3 (choline transport blocker) and pirenzepine (specific antagonist of M1 receptor), but not by gallamine (specific antagonist of M2 receptor). The results of the present study provided further evidence for a strong GABAergic/cholinergic interaction in the neural mechanism responsible for production of theta-like activity in the hippocampal formation slices.     

Clinical application of the forced inspiratory volume-time curve. A preliminary study

The forced inspiratory volume-time curve in 25 health subjects with normal ventilation function and 25 patients with COPD were determined, and MMIF, FIV were calculated from the curves. The PImax was measured in the same 50 subjects by modified Blac method sequentially. A close relationship between MMIF, FIV and PImax was found. This result indicated that MMIF and FIV could be indeed for evaluation of strength of respiratory, muscles. Additional observations of MMIF, FIV and PImax in 50 patients with COPD before and after inotropic drugs, aminophylline and CNB, further proved the validity of MMIF and FIV.     

Sibling relationship quality and adolescent delinquency: A latent growth curve approach.

The present study examined whether level and changes in sibling relationship quality and older sibling delinquency are related to level and changes in younger sibling delinquency, for brother, sister, older brother/younger sister and older sister/younger brother sibling pairs. Questionnaire data were collected from 249 Dutch sibling pairs (11–15 years old) over a period of three years, with annual measurements. Results showed that level and over-time changes in sibling relationship quality and older and younger sibling delinquency were significantly different for the four sibling gender combinations. Results of multivariate growth curve modeling showed that sibling relationship quality was related to delinquency of older siblings (but not younger siblings), and delinquency of older siblings was associated with younger sibling delinquency two years later. We also found differences between the four sibling gender combinations. For example, for brother and sister pairs (but not mixed-sex sibling pairs), over-time changes in older sibling delinquency were related to younger sibling delinquency two years later as well as the change pattern in younger sibling delinquency over time. Strengths, limitations and possible implications for research and intervention of adolescent delinquency are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impairment of growth and immune function of avocet chicks from sites with elevated selenium, arsenic, and boron

Avocets (Recurvirostra americana) hatched from eggs collected from the south Central Valley of California (USA) were studied to determine the impact of elevated concentrations of selenium, arsenic, and boron on the immune system and growth to maturity. Corcoran ponds were the reference site with low selenium (1.2 ppb) and arsenic (29 ppb) (boron not measured). Westfarmers Pond had elevated concentrations of selenium (319 ppb), arsenic (127 ppb), and boron (109 ppm). Pryse ponds also had elevated selenium, arsenic, and boron concentrations (13.9 ppb, 1,100 ppb, and 29.4 ppm, respectively). Size at hatch was significantly reduced (P < or = 0.05) in birds from Westfarmers and Pryse ponds. The growth rate was faster, but mean adult size was reduced in birds from Pryse ponds. Avocet chicks from Pryse and Westfarmers ponds exposed solely through in ovo transfer of these elements had significantly increased heterophil:lymphocyte ratios. The phagocytic activity of macrophages also was significantly reduced in these birds, and Pryse Pond birds had an increased proliferative ability of lymphocytes in the presence of concanavalin A, a T-cell mitogen. Avocet chicks (< or = 5 wk old) were captured from the various ponds and the same morphometric and immune function measurements made. The birds that were most severely impacted by exposure to these compounds were those that were collected from Pryse ponds.     

The impact of service characteristics on functional outcomes from community support programs for persons with schizophrenia: A growth curve analysis.

A total of 172 individuals diagnosed with a schizophrenia spectrum disorder were followed for 36 months in 3 distinct models of community-based care. Functional outcome data gathered every 6 months were combined with service implementation data to test hypotheses concerning the impact of service characteristics on prospective client outcomes. The results using hierarchical linear modeling supported associations between the intensity, specificity, and longitudinality of services and improved client outcomes. Specifically, more intense services were associated with higher levels or rates of improvement on all indices of clinical and psychosocial functioning. The specificity results suggested that services needed to be targeted to specific areas of functioning in order for improvement to occur. The effect of longitudinality was contingent on the outcome domain examined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Grain growth behavior of tungsten heavy alloys based on the master sintering curve concept

Time and temperature relationships for grain growth by Ostwald ripening are transformed into the master sintering curve (MSC) form. The resulting MSC equations are used to analyze grain size data obtained from W-Ni-Fe heavy alloys that were quenched from sintering temperatures ranging from 1200 °C to 1500 °C. Activation energies for grain growth during both solid-state and liquid-phase sintering are calculated and compared to experimental values for diffusion. The MSC equations are further modified to include the effect of the solid volume fraction on the grain growth constant. A sensitivity analysis of material properties and process variables shows that the grain growth rate constant is most affected by changes in the sintering temperature and activation energy.     

Attitude, social influence, and self-efficacy among Chinese participants of chronic disease self-management program: A latent growth curve modeling study.

Objectives: This study aimed to examine temporal relationships among psychological parameters (readiness to change, changes in self-efficacy [SE], social norm [SN], attitude [AT]) and two self-management behaviors: cognitive symptom management (CSM) and tangible help-seeking (TH) by constructing latent growth change models. Method: This was a longitudinal study of 60 Chinese participants with various chronic diseases who completed a 6-week chronic disease self-management program. Psychological and behavioral variables were assessed at the beginning of the 1st, 4th, and 6th week of the program. Results: Latent growth change curve analysis revealed that, in the early stages of engagement in CSM, SE was a key determinant of behavior. During the 6-week period, changes in SE were influenced directly by both SN and AT. When engaging in TH, SE influenced the behavior with direct and indirect effect from AT and SN. Readiness for change, on the other hand, appeared to be more associated with psychological rather than behavioral changes. This study revealed different underlying change mechanisms for two types of self-management behaviors. Conclusion: The findings shed light on program modifications that could further strengthen the therapeutic effects of the program. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Developmental, family, and ethnic in influences on adolescent alcohol usage: A growth curve approach.

The influence of the developmental process of individuation, family conflict and cohesion, and ethnicity on adolescent alcohol use was examined in a 3-year longitudinal study. Participants included non-Hispanic White, Mexican American, and African American adolescents (n?=?6,522) from 6th, 7th, and 8th grades. They were surveyed annually for 3 years. Depending on which aspect of individuation was measured, hierarchical linear modeling indicated that changes in adolescent individuation were related to either increases or decreases in alcohol use over the 3-year period. Separation and family conflict were related to increases in alcohol use, and intergenerational individuation and family cohesion were related to decreases in alcohol use. White and Mexican American adolescents had a faster rate of increase in alcohol use than did African American youth. Separation and family process similarly influenced adolescent alcohol use from different ethnic groups. Implications for prevention and intervention programs are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexing day-old chicks: A case study and expert systems analysis of a difficult perceptual-learning task.

The sexing of day-old chicks has been regarded as an extraordinarily difficult perceptual task requiring years of extensive practice for its mastery. Experts can sex chicks at over 98% accuracy at a rate of 1,000 chicks per hour spending less than a half second viewing the cloacal region. Naive subjects were shown 18 pictures of cloacal regions of male and female chicks (in random appearing arrangement) and asked to judge the sex of each chick. The pictures included a number of rare and difficult configurations. The subjects were then instructed as to the location of a critical cloacal structure for which a simple contrast in shape (convex vs. concave or flat) could serve as an indicant of sex. When the subjects judged the pictures again (in a different order), accuracy increased from slightly above chance to a level comparable to that achieved by a sample of experts. The correlation (over items) between the naive subjects and the experts before instruction was .21; after instruction, .82. The instructions were based on an interview and observation of an expert who had spent 50 years sexing 55 million chicks. Much of the reported difficulty in developing perceptual expertise in this task may stem from the need to classify extremely rare configurations in which the convexity of the structure is not apparent. The rate of learning of these instances could be greatly increased through the use of simple instructions that specified the location of diagnostic contour contrasts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluating model fit for growth curve models: Integration of fit indices from SEM and MLM frameworks.

Evaluating overall model fit for growth curve models involves 3 challenging issues. (a) Three types of longitudinal data with different implications for model fit may be distinguished: balanced on time with complete data, balanced on time with data missing at random, and unbalanced on time. (b) Traditional work on fit from the structural equation modeling (SEM) perspective has focused only on the covariance structure, but growth curve models have four potential sources of misspecification: within-individual covariance matrix, between-individuals covariance matrix, marginal mean structure, and conditional mean structure. (c) Growth curve models can be estimated in both the SEM and multilevel modeling (MLM) frameworks; these have different emphases for the evaluation of model fit. In this article, the authors discuss the challenges presented by these 3 issues in the calculation and interpretation of SEM- and MLM-based fit indices for growth curve models and conclude by identifying some lines for future research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of dietary supplementation with alpha-linolenic acid on the phospholipid fatty acid composition and quality of spermatozoa in cockerel from 24 to 72 weeks of age

The physiopathology of experimental cerebral malaria (CM), an acute neurological complication of Plasmodium berghei ANKA (PbA) infection, involves interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha), two cytokines that are known to modulate major histocompatibility complex (MHC) molecule expression. The aim of this study was to evaluate whether the genetic susceptibility to CM is related to the constitutive or IFN-gamma-induced expression of MHC molecules on brain microvessels. To this end, brain microvascular endothelial cells (B-MVEC) were isolated from CM-susceptible (CM-S, CBA/J) and resistant (CM-R, BALB/c) mice. By flow cytometry, we found that less than 5% of CM-S B-MVEC constitutively expressed MHC class I molecules, in contrast to up to 90% of CM-R B-MVEC. Upon stimulation with IFN-gamma, the percentage of positive cells for MHC class I molecules in CM-S B-MVEC became comparable to CM-R B-MVEC, but a higher fluorescence intensity existed on CM-S B-MVEC compared with CM-R B-MVEC. MHC class II molecules were not constitutively expressed on B-MVEC from either strain. IFN-gamma-induced expression of MHC class II (I-A, I-E) molecules was significantly higher in CM-S than CM-R B-MVEC both in percentage of positive cells and fluorescence intensity. These data demonstrate that absent or low MHC class I and higher inducibility of MHC class II expression on B-MVEC are associated with the genetic susceptibility to CM.     

Behavior problem trajectories and first-grade cognitive ability and achievement skills: A latent growth curve analysis.

Using data from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development, the authors investigated whether there was evidence of intraindividual stability in behavior problems over time as well as whether children with higher levels of behavior problems at 24 months and more rapid increases in behavior problems prior to school entry performed more poorly on 1st-grade tests of cognitive ability and achievement than their peers. Three findings were noteworthy. First, there was evidence of both intraindividual and interindividual variability in behavior problems between 24 months and 1st grade. Second, children with higher initial levels of internalizing and externalizing behaviors at 24 months had lower cognitive ability and achievement scores in 1st grade. Finally, children with more rapid increases in internalizing behaviors over time had lower cognitive ability scores in 1st grade; this association did not exist for externalizing behaviors. Implications for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A development of the oxyhemoglobin dissociation curve analyzer

The development and improvement of an oxyhemoglobin dissociation curve analyzer is described. PO2 electrode performance was improved by electrochemical means and circuits are described for processing the PO2 and pH signals from the analyzer. A circuit for automatically correcting the curve for Bohr shifts from pH 7.40 is described, and the performance of the Bohr shift unit is verified by experiment. The analyzer produces curves under standard conditions of PCO2 40 mmHg, pH 7.40, and 37 degrees C.     

Application of a growth curve approach to modeling the progression of Alzheimer's disease

BACKGROUND: Studies using clinical measures to track AD progression often assume linear declines over the entire course of the disease, which may not be justified. The objective of this study was to model change in measures of the clinical severity of Alzheimer's disease (AD) over time. METHODS: We developed a method to apply growth curve models to prospective data and characterize AD patients' functional change over time. Data from the modified Mini-Mental State Examination (mMMSE) and measures of basic and instrumental ADL, administered semiannually for up to 5 years to 236 patients with probable AD, were modeled. RESULTS: The rate of decline in mMMS scores per 6-month interval gradually increased as scores dropped from the maximum of 57 to 20. The rate of decline then decreased as scores approached 0, resulting in an inverse "S" curve. The rate of increase in instrumental ADL scores per interval attenuated as the scores increased, while that for basic ADL scores across intervals was constant. CONCLUSIONS: Differences in the pattern of progression of the three measures is in part a function of their psychometric properties. The progression curves may also reflect content-specific features of the instruments. Superimposition of the modeled decline in these three content areas suggests a hypothetical model of the relative timing of cognitive and functional changes in AD.     

A study of CGRP receptor and its effect on the growth of human pancreatic carcinoma cells

Immunologic reactions occurring after allogeneic bone marrow transplantation, known as graft-versus-leukemia effect, contribute significantly to the control of minimal residual disease and decreased risk of relapse post-transplant. Graft-versus-leukemia reactions occur with or without graft-versus-host disease and are either mediated through T-cells or are independent of T-cells. The contribution made by graft-versus-leukemia reactions to improvement in overall survival depends upon the underlying type of leukemia, the nature of the marrow graft and the morbidity of any associated graft-versus-host disease. This article reviews the evidence demonstrating graft-versus-leukemia effect in clinical bone marrow transplantation, some approaches to dissociate graft-versus-leukemia from graft-versus-host disease, and attempts to induce graft-versus-leukemia reactions in the setting of autologous bone marrow transplantation by immunotherapy.     

Immunochemical isolation and characterization of vitellogenin mRNA from liver of estradiol-treated chicks

Several commercially available samples of galactose oxidase (D-galactose: oxygen 6-oxidoreductase, EC 1.1.3.9) were found to contain high proteolytic activity on proteins such as fibrinogen, transferrin, albumin and casein. A simple, efficient method was devised for the purification of galactose oxidase which relies on the affinity of the enzyme for agarose (Sepharose 6B). The purified galactose oxidase was recovered in high yield free from proteolytic activity. The enzymic affinity for Sepharose and Sephadex was investigated to clarify the absorption mechanism.     

Value of the shape of the flowmetry curve in the study of prostatism

OBJECTIVE: To determine the relation of the urinary flow curve morphology of free flowmetry with the status of lower urinary tract dynamics. METHODS: A mathematical model was designed to fit the urinary flow curves to two models: a symmetrical and an asymmetrical model. Based on these models we analyzed the relationship between the presence or absence of obstruction and the type of model which better adjusted the urinary flow curves in a series of 85 males. RESULTS: The urinary flow curves corresponding to absence of obstruction adjusted significantly better to a symmetrical model than those corresponding to bladder outlet obstruction. No correlation was observed between the type of curve and bladder contractibility or type of urinary obstruction. CONCLUSIONS: There is a relationship between the form of the urinary flow curve and bladder obstruction. In the absence of obstruction, the urinary flow curves are more symmetrical.