60 POWER-AGERS: IMPLEMENTING PROGRESSIVE RESISTANCE TRAINING TO MANAGE SARCOPENIA AMONG COMMUNITY DWELLING OLDER ADULTS

Background

The prevalence of sarcopenia among community dwelling older adults is between 10-40%. Progressive Resistance Training (PRT) improves sarcopenia and functional performance among older-adults. A PRT programme was introduced to a Day Hospital service as part of a sarcopenia management quality improvement initiative.

Methods

The PRT programme was implemented on a phased basis. Phase 1 evaluated the feasibility, safety and participant satisfaction. Phase 2 then collected pre and post outcome measures (gait-speed, grip strength and 5-Times-Sit-to-Stand [5TSTS]), and a patient perception questionnaire. The intervention consisted of a physiotherapist-lead PRT programme (weekly in phase 1 and biweekly in phase 2). Recent community dwelling Day Hospital attendees were recruited by the physiotherapist to participate. The class consisted of a circuit of 4-6 exercises targeting upper and lower limbs, along with an educational component. Exercises were progressively overloaded on an individual basis.

Results

Ten participants attended the PRT programmes (phase 1 [n=5], phase 2 [n=5]). Most were female (n=6), mean age was 84 years. None had prior formal experience of PRT. The phase 1 PRT group was deemed feasible and safe in an outpatient setting. All phase 1 participants (n=5) felt it was beneficial and rated it 5/5. All phase 2 participants had improvements in sarcopenia markers (grip strength [range=1kg-9kg], gait-speed [range=0.04m/s-0.19m/s], and 5TSTS [range=5.1sec-11sec]). All participants reported that the programmes improved their confidence in PRT and that they were interested in continuing PRT in the future.

Conclusion

This supports that PRT a clinical setting with community dwelling older adults is safe, feasible and effective in improving sarcopenia markers. Furthermore, the high rate of satisfaction supports its use with this population. Further research is required to examine the impact of combined nutritional education with strength training as an intervention for older adults with sarcopenia.

A multicentre longitudinal observational study of changes in self reported health status in people with Parkinson's disease left untreated at diagnosis

BACKGROUND

The issue of when to start treatment in Parkinson's disease (PD) remains controversial. Some favour treatment at diagnosis while others opt for a "wait and watch" policy. The effect of the latter policy on the self reported health status of people with PD is unknown.

AIMS

To record self reported health status through longitudinal use of a validated PD specific questionnaire (PDQ-39) in untreated PD patients in multiple centres in the UK. To compare patients who were left untreated with those who were offered treatment during follow-up.

METHODS

A multicentre, prospective, "real life" observational audit based study addressing patient reported outcomes in relation to self reported health status and other sociodemographic details.

RESULTS

198 untreated PD were assessed over a mean period of 18 months. During two follow-up assessments, the self reported health status scores in all eight domains of the PDQ-39 and the overall PDQ-39 summary index worsened significantly (p<0.01) in patients left untreated. In a comparative group in whom treatment was initiated at or soon after diagnosis, there was a trend towards improvement in self reported health status scores after treatment was started.

CONCLUSIONS

This study addresses for the first time self reported health status, an indicator of health related quality of life, in untreated PD. The findings may strengthen the call for re-evaluation of the policy to delay treatment in newly diagnosed patients with PD.

The dopamine D(1) receptor agonist SKF-82958 serves as a discriminative stimulus in the rat

We examined the discriminative stimulus effects of the high-efficacy dopamine D(1) receptor agonist (+/-)6-chloro-7, 8-dihydroxy-3-ally1-phenyl-2,3,4,5-tetrahydro-1H-3benzazepine++ + hydrobromide (SKF-82958) in rats trained to discriminate SKF-82958 (0.03 mg/kg) from vehicle in a two-lever food-reinforced drug discrimination task. SKF-82958 produced dose-related increases in responding to the SKF-82958 appropriate lever with full substitution occurring at the training dose. Pretreatment with the dopamine D(1)/D(5) receptor antagonist (-)-trans-6,7,7a,8,9, 13b-hexahydro-3-chloro-2hydroxy-N-methyl-5H-benzo-[d]naphtho -¿2, 1-b¿azepine (SCH-39166) (0.01 mg/kg) attenuated the discriminative stimulus effects of SKF-82958. Pretreatment with the dopamine D(2) receptor antagonist raclopride (0.03 mg/kg) had no effect. The high-efficacy dopamine D(1) receptor agonist R(+)6chloro-7, 8-dihydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrobromide (SKF-81297) fully substituted for SKF-82958, whereas the low-efficacy dopamine D(1) receptor agonist (+/-)1-phenyl-2,3,4, 5-tetrahydro-(1H)-3-benzazepine-7,8-diol hydrochloride (SKF-38393) produced only partial substitution. The dopamine D(2) receptor agonist trans-(+/-)-4,4a,5,6,7,8,8a, 9-octahydro-5-propyl-1H-propyl-1H-pyrazolo[3,4-g]quinoline dihydrochloride (quinpirole) and the indirect dopamine agonist cocaine did not substitute fully for the SKF-82958 discriminative stimulus cue. These results demonstrate that the high-efficacy dopamine D(1) receptor agonist SKF-82958 can serve as an effective discriminative stimulus in the rat, and that these effects are mediated by a dopamine D(1)-like receptor mechanism.

Heritability of MMPI Harris-Lingoes and Subtle-Obvious subscales in twins reared apart

A large sample of identical and fraternal twins who had been reared apart was used to examine the genetic and environmental architecture of the MMPI Subtle-Obvious and Harris-Lingoes subscales. Univariate genetic analyses indicated significant heritability for all 28 of the Harris-Lingoes subscales (estimates ranged from.23 to.61), all five Obvious subscales (estimates ranged from.37 to.56) and four of the five Subtle subscales (estimates ranged from.27 to.35). Two randomly constructed scales were analyzed as controls; neither of these scales showed significant heritability. Exploratory correlational findings suggested that three of the Wiener-Harmon Subtle subscales may tap aspects of psychological health, naivete, or repression. Ma-S may come closest to Wiener and Harmon s intent. Although they apparently diverge from their original purpose, it may be too early to abandon the low face valid items of the Subtle subscales.

Antisocial behavior, substance use, and somatization in families of adolescent drug abusers and adolescent controls

Symptoms of conduct disorder (CD), antisocial personality disorder (ASP), alcohol abuse, drug abuse, and somatization were tabulated for the families of 35 delinquent, substance-abusing (multiple-problem) adolescent male probands and 35 age-matched control males. Alcohol abuse, CD/ASP, and somatization were assessed with either the Diagnostic Interview Schedule (DIS) (for participants aged 18 and up) or the Diagnostic Interview for Children and Adolescents (DICA) (for participants aged 12 to 17). Drug abuse for all participants was assessed with the Substance Abuse Module (SAM) of the Comprehensive Interview for Diagnostic Evaluation (CIDE). As expected, proband groups had significantly more (p < .0001) CD/ASP, alcohol abuse, and drug abuse symptoms than control groups. A significant (p < .01) positive correlation among CD/ASP, alcohol abuse, and drug abuse was found for each group. Somatization was not differentially associated with proband status. It was concluded that identifying male multiple-problem youths also identifies families with a high incidence of similar problems.

p53 overexpression and downregulation of inter-alpha-inhibitor are associated with hyaluronidase enhancement of TNF cytotoxicity in L929 fibroblasts

Degradation of extracellular matrix by hyaluronidase increases murine L929 cell sensitivity to tumor necrosis factor (TNF) cytotoxicity. Seeding and culturing L929 cells onto the matrix of serum fetuin and the hyaluronate-binding inter-alpha-inhibitor resulted in inhibition of hyaluronidase-enhanced TNF killing, suggesting that the release of these proteins from hyaluronidase-degraded matrix confers cellular TNF susceptibility. Metabolic labeling studies showed that hyaluronidase mediated de novo protein synthesis and down regulated several proteins in L929 cells. Specifically, hyaluronidase upregulated p53 protein expression (>200%) but down regulated a p85 inter-alpha-inhibitor-like protein (>90%) in L929 cells, whereas it had no effect on the protein levels of ICH-1, Bcl-xL, Bcl-2, Fas ligand, CAS (cellular apoptosis susceptible protein), TIAR (an RNA-binding protein) and alpha-tubulin. Conceivably, hyaluronidase enhancement of TNF sensitivity in L929 cells is p53-dependent and the matrix inter-alpha-inhibitor contributes a protective role against TNF cytotoxicity.

JL13, a pyridobenzoxazepine compound with potential atypical antipsychotic activity: a review of its behavioural properties

The search for an improved clozapine-like compound has resulted in the selection of a new molecule: JL13 (5-(4-methylpiperazin-1-yl)-8-chloro-pyrido[2,3-b][1,5] benzoxazepine fumarate). Like clozapine, JL13 did not antagonize apomorphine-induced stereotypy and did not produce catalepsy but antagonized apomorphine-induced climbing in rodents (ID50 = 3.9 mg kg-1 s.c.). It was inactive against d-amphetamine-induced stereotypy but antagonized d-amphetamine-induced hyperactivity in the mouse (ID50 = 4.4 mg kg-1 i.p.). JL13, like clozapine, was able to antagonize (+/-)-DOI-induced head-twitches in the mouse (ID50 = 2.0 mg kg-1 i.p.). In the open-field test in the rat and forced swimming test in the mouse a high similarity was noted between the two drugs in the same range of doses. In a complex temporal regulation schedule in the dog, JL13 showed a high resemblance with clozapine without inducing sialorrhea, palpebral ptosis or any significant motor side effects. In rats trained to discriminate clozapine, JL13 (10 mg kg-1 i.p.) induced a high level of generalization (70%) to clozapine. In a drug discrimination procedure in the squirrel monkey, JL13 (3-10 mg kg-1 i.m.) produced a full substitution of clozapine. On the basis of these preclinical data, it is thus predicted that JL13 would be a promising atypical antipsychotic drug.

Genetic and environmental architecture of human aggression

A meta-analysis was performed on data from 24 genetically informative studies by using various personality measures of aggression. There was a strong overall genetic effect that may account for up to 50% of the variance in aggression. This effect was not attributed to methodological inadequacies in the twin or adoption designs. Age differences were important. Self-report and parental ratings showed genes and the family environment to be important in youth; the influence of genes increased but that of family environment decreased at later ages. Observational ratings of laboratory behavior found no evidence for heritability and a very strong family environment effect. Given that almost all substantive conclusions about the genetics of personality have been drawn from self or parental reports, this last finding has obvious and important implications for both aggression research in particular and personality research.

Characterization of an insulin-like growth factor (IGF) receptor and the insulin-like effects of IGF-1 in the bony fish, Lates calcarifer

The present work is part of a broad phylogenetic study of the insulin superfamily of peptides in lower vertebrates. In the bony fish barramundi (Lates calcarifer), the presence of IGF receptors were investigated in the liver by means of competitive binding studies. The results suggested the presence of a type 1-like but no type 2-like IGF receptor. We also demonstrated insulin-like effects of intraperitoneally injected recombinant human (rh)-IGF-1 in barramundi with rh-IGF-1 and rh-insulin showing similar effects with respect to induction of hypoglycemia and stimulation of incorporation of [14C]-glucose into muscle glycogen.

Heritability of MMPI personality indicators of psychopathology in twins reared apart

This report presents Minnesota Multiphasic Personality Inventory (MMPI) findings from the Minnesota Study of Twins Reared Apart. Data from 65 unique pairs of monozygotic twins reared apart (MZA) and 54 unique pairs of dizygotic twins reared apart (DZA) were analyzed. As in other results from this sample, MZA twins evidenced substantial similarity, highlighting the influence of shared genes. Biometric modeling yielded estimates of heritability for the MMPI's standard validity and clinical scales and for the Wiggins content scales ranging from .26 to .62 (M = .44), echoing previous findings from the twin and adoption literature on personality. The pattern of MZA and DZA correlations suggested nonadditive genetic effects for 3 MMPI scales. Multivariate profile analyses also suggested genetic influence on both profile elevation and shape.

Genetic and environmental architecture of human aggression

A meta-analysis was performed on data from 24 genetically informative studies by using various personality measures of aggression. There was a strong overall genetic effect that may account for up to 50% of the variance in aggression. This effect was not attributed to methodological inadequacies in the twin or adoption designs. Age differences were important. Self-report and parental ratings showed genes and the family environment to be important in youth; the influence of genes increased but that of family environment decreased at later ages. Observational ratings of laboratory behavior found no evidence for heritability and a very strong family environment effect. Given that almost all substantive conclusions about the genetics of personality have been drawn from self or parental reports, this last finding has obvious and important implications for both aggression research in particular and personality research.

Heritability of MMPI personality indicators of psychopathology in twins reared apart

This report presents Minnesota Multiphasic Personality Inventory (MMPI) findings from the Minnesota Study of Twins Reared Apart. Data from 65 unique pairs of monozygotic twins reared apart (MZA) and 54 unique pairs of dizygotic twins reared apart (DZA) were analyzed. As in other results from this sample, MZA twins evidenced substantial similarity, highlighting the influence of shared genes. Biometric modeling yielded estimates of heritability for the MMPI's standard validity and clinical scales and for the Wiggins content scales ranging from .26 to .62 (M = .44), echoing previous findings from the twin and adoption literature on personality. The pattern of MZA and DZA correlations suggested nonadditive genetic effects for 3 MMPI scales. Multivariate profile analyses also suggested genetic influence on both profile elevation and shape.

The incidence of antibody formation to OKT3 consequent to its use in organ transplantation

Enzyme-linked immunosorbent assays were performed on 12,133 serum samples to determine the incidence of anti-OKT3 antibody formation among transplant recipients who had received OKT3 for rejection treatment or prophylaxis. High anti-OKT3 antibody titers (> or = 1:1000) were detected in 5.8% of samples drawn 2 to 8 weeks following initiation of OKT3 therapy. The frequency of high titers differed by organ (6.9%, 2.7%, and 5.3% for kidney, heart, and liver, respectively; P < 0.001) and by sampling times (P < 0.001). The highest frequency of positive titers was obtained in samples obtained between 2 and 4 weeks following the initiation of OKT3. For all transplant recipients and for kidney recipients alone, multivariate logistic regression showed that the risk of high anti-OKT3 titers varied significantly at 2 to 4 weeks and at 4 to 6 weeks (but not at 6 to 8 weeks) with age (the youngest patients had the highest incidence, with a steady decline after age 30; P < 0.05), course of therapy (lowest frequencies followed a first course of OKT3; P < 0.001), and transplant number (lowest frequencies followed a first transplant; P < 0.01). Analyses of a set of patients on whom immunosuppressive regimen information was available indicated that prophylactic or maintenance treatment with CsA was associated with a significantly lower frequency of high-titer anti-OKT3 antibodies than was therapy without CsA (P < 0.001). In conclusion, this series provides confirming evidence that high-titer anti-OKT3 antibodies, which are of concern whenever retreatment with OKT3 is contemplated, occur in a low percentage of patients and are associated with such factors as age, previous transplantation or courses of therapy with OKT3, and treatment with CsA.

A twin study of non-alcohol substance abuse

Except for alcohol abuse, little is known about the familial aggregation for substance abuse. Here we report twin resemblance for non-alcohol substance use in the Washington University Twin Series, wherein probands were identified by consecutive admission to psychiatric facilities in the St. Louis area. A 5-point substance abuse scale was constructed with values anchored by never used drugs (1) to drug dependence (5). Year of birth was the most powerful predictor of drug use--younger twins scored far higher than older twins. Either heritability or common environment had to be included in the regression model to avoid a significant drop in explained variance, but which was more important could not be resolved. The correlation for identical twins exceeded that for fraternal twins, suggesting the possibility of a heritable factor.

Genetic association study in psychiatry: analytical evaluation and a recommendation

Recent analysis of the candidate gene, association study for psychiatric disorders have concluded that most statistically significant results are likely to be false positives because there are a large number of potential candidate loci and a low a priori probability that a given candidate locus will in fact be trait relevant. Hence, it was recommended that the alpha level (P level) be lowered for association studies. The present study demonstrates that lowering the alpha level to some fixed, predetermined value is not a recommended strategy. Rather, the probability of false positives (and false negatives) depends on such parameters as the prevalence of the disorder, the prevalence of the genotypes at the candidate locus, and the relative risk. In some areas of the parameter space, the adjustment to alpha may be modest. In other areas, however, even the requirement of one or more independent replications of the original results gives false positive rates exceeding 80% or 90%. Hence, the P levels required to minimize false positives may have to be changed from one statistical test to another even within the same study. A procedure for adjusting the probability level for a test of association between genotypes and a disorder is given.

Personality and psychopathology: genetic perspectives

Genetic factors exert an important influence on adult personality traits, accounting for anywhere between 30% and 60% of the variance. Heredity is also important for most forms of psychopathology and plays a major role in several theories that relate personality to psychopathology. Despite this, there has been surprisingly little multivariate genetic research reported on joint analyses of personality and psychopathology. The small amount of available data suggests that genes may account for over 50% of the observed correlation between neuroticism and state symptoms of anxiety and depression. The mechanisms behind such strong genetic correlations are crucial for understanding the causal relationship between a personality trait and a disorder because genetically influenced biological systems may operate as exogenous "third-party" factors that are responsible for what appear to be phenotypic cause-effect relationships. We illustrate how recent analytical advances in behavior genetics can use multivariate family data to address questions about the causal role of personality in psychopathology.

Personality and psychopathology: genetic perspectives

Genetic factors exert an important influence on adult personality traits, accounting for anywhere between 30% and 60% of the variance. Heredity is also important for most forms of psychopathology and plays a major role in several theories that relate personality to psychopathology. Despite this, there has been surprisingly little multivariate genetic research reported on joint analyses of personality and psychopathology. The small amount of available data suggests that genes may account for over 50% of the observed correlation between neuroticism and state symptoms of anxiety and depression. The mechanisms behind such strong genetic correlations are crucial for understanding the causal relationship between a personality trait and a disorder because genetically influenced biological systems may operate as exogenous "third-party" factors that are responsible for what appear to be phenotypic cause-effect relationships. We illustrate how recent analytical advances in behavior genetics can use multivariate family data to address questions about the causal role of personality in psychopathology.

Path analysis and sib-pair linkage

When the distance between linked loci is expressed in terms of the correlation between the identity-by-descent (idb) values of the loci, then a path model may be used to order loci with data on sib-pairs and their parents. The relationship between the recombination fraction and the correlation coefficient is developed and a method for fitting a covariance matrix predicted by a specific ordering of loci to an observed covariance matrix is proposed.

Identifying children in the Colorado Adoption Project at risk for conduct disorder

Clustering techniques were used to identify a subsample of young adopted and nonadopted children in the Colorado Adoption Project at risk for conduct disorder. Although data from both boys and girls were analyzed, a cluster of girls large enough for subsequent statistical analysis could not be identified; therefore, results are reported for boys only. Identifying measures were selected based on the DSM-III-R diagnostic criteria. Cluster analyses confirmed the existence of a small group of boys who appeared to be significantly at risk. Subsequent parental and teacher ratings of these children verified the stability over time of the classification. The poor conduct group was significantly associated with difficult temperament in infancy, with poor conduct on the part of parents when they were youths, and with high achievement orientation in the home environment.

Simulated twin data on substance abuse

Twin data were simulated for use of a new illegal substance. The twin cohort was "measured" yearly at 10 time intervals during the diffusion of the substance throughout the nation. The models used to generate the data are discussed.

Twin imitation for antisocial behavior: implications for genetic and family environment research

When twin pairs influence each other's behavior, observed variance is greater for MZ twins than for DZ twins under at least 1 of 2 conditions: (a) the trait has some heritability and (b) MZ twins influence each other more than do DZ twins. Applied to a trait that has an underlying continuous distribution but is measured as a dichotomy, the presence of reciprocal twin influence predicts that if the base rate for the trait is not exactly 50%, then the prevalence of the trait should differ in MZ and DZ twin pairs. This prediction held for registered criminality in a large twin cohort. Methods of analysis that permit reciprocal twin interaction not only provide better statistical fits to the data but also yield estimates of heritability that agree with adoption data. The results suggest that the genetic influence on registered criminality may be more modest than previously thought.

Twin imitation for antisocial behavior: Implications for genetic and family environment research

When twin pairs influence each other's behavior, observed variance is greater for MZ twins than for DZ twins under at least 1 of 2 conditions: (a) the trait has some heritability and (b) MZ twins influence each other more than do DZ twins. Applied to a trait that has an underlying continuous distribution but is measured as a dichotomy, the presence of reciprocal twin influence predicts that if the base rate for the trait is not exactly 50%, then the prevalence of the trait should differ in MZ and DZ twin pairs. This prediction held for registered criminality in a large twin cohort. Methods of analysis that permit reciprocal twin interaction not only provide better statistical fits to the data but also yield estimates of heritability that agree with adoption data. The results suggest that the genetic influence on registered criminality may be more modest than previously thought.

Parent-offspring and sibling adoption analyses of parental ratings of temperament in infancy and childhood

A first step toward understanding the etiology of personality is to investigate the relative impact of genetic and environmental factors using twin and adoption designs. Twin studies of infants and young children indicate substantial genetic influence for parental ratings of temperament in the preschool years. Adoption studies, however, have not previously been reported during the early years of life. We present parent-offspring comparisons for temperament (emotionality, activity, sociability, and impulsivity) for adopted and nonadopted children yearly from 1 to 7 years of age and their biological, adoptive, and nonadoptive parents. Also presented are correlations for adoptive and nonadoptive siblings when each child was 1, 2, 3, and 4 years of age. In contrast with twin results, little evidence is found for genetic influence. The average correlation between biological parents and their adopted-away children for data averaged over the 7 years is only .03. Similarly, the average parent-offspring correlation in nonadoptive families (.08) is no greater than in adoptive families (.12). Results for nonadoptive and adoptive siblings also indicate little genetic influence. The difference between the twin and adoption results may be due to environmental effects or to nonadditive genetic variance.

Codistribution of a sensory gating deficit and schizophrenia in multi-affected families

Because the clinical diagnosis of schizophrenia has not generally been an adequate phenotypic marker to detect the genes that convey risk for schizophrenia, efforts have been directed toward the identification of more elementary neuronal dysfunctions in schizophrenic patients and their families. Psychophysiological studies of sensory gating and selective attention suggest that defects in these brain functions are present in schizophrenic patients and some of their relatives. This study examines one of these defects in sensory gating, failure to suppress the P50 evoked response to repeated auditory stimuli. Six pedigrees, chosen because of the presence of large sibships containing several cases of schizophrenia, were studied. A mathematical model was developed to assess the familial association of the P50 defect with schizophrenia. The model preserves the quantitative nature of the data and is suitable for use in a sample with small numbers of pedigrees comprising many individuals. It is thus suitable for the evaluation of putative phenotypes in families to be studied by linkage analysis with polymorphic genetic markers. The results suggest that the P50 defect is familially associated with schizophrenia.

Linkage analysis of quantitative traits: increased power by using selected samples

Although a number of methods have been developed for linkage analysis of quantitative traits, power is relatively poor unless there is a single major locus of very large effect. Here it is demonstrated that the use of selected samples (i.e., ascertainment of a proband with an extreme score on the quantitative measure) can dramatically increase power, especially when proband selection is performed on the tail of a distribution with an infrequent recessive gene. Depending on gene action and allele frequency, selected samples permit detection of a major locus that accounts for as little as 10%-20% of the phenotypic variation. The judicious use of selected samples can make an appreciable difference in the feasibility of linkage studies for quantitative traits.

Evolution and path models in human behavioral genetics

The evolutionary implications of the path-analysis model most often used in human behavior genetics are examined. With directional selection, a model of pure vertical environmental transmission does not respond in a fully adaptive fashion. Unless the coefficients of transmission are exactly 0.50, the population mean will not equilibrate at the selective optimum over time. If there is both genetic and vertical environmental transmission, then the population mean can equilibrate at the selective optimum. In the presence of genetic transmission, vertical environmental transmission increases population fitness and has a strong effect on the rapid movement of the mean toward the selective optimum. This raises the intriguing paradox of why empirical evidence suggests that vertical environmental transmission is usually small when it possesses such important fitness properties.

The Ciba Corning ACS:180 benchtop immunoassay analyzer

We describe a new clinical laboratory instrument, the ACS:180, used to automate heterogeneous immunoassay testing. The ACS:180 automates immunoassays in which paramagnetic particles are the solid phase and changes in chemiluminescence are measured. The system can accommodate both competitive and sandwich-type assay configurations. The microprocessor-based instrument fully automates each step of the assay, including sample and reagent addition, separation and wash of paramagnetic particles, and generation and acquisition of the chemiluminescent signal. The instrument has the flexibility to operate in random-access or batch mode. The time from application of sample to first result is less than 15 min; throughput is as much as 180 tests per hour.

The Ciba Corning ACS:180 benchtop immunoassay analyzer

We describe a new clinical laboratory instrument, the ACS:180, used to automate heterogeneous immunoassay testing. The ACS:180 automates immunoassays in which paramagnetic particles are the solid phase and changes in chemiluminescence are measured. The system can accommodate both competitive and sandwich-type assay configurations. The microprocessor-based instrument fully automates each step of the assay, including sample and reagent addition, separation and wash of paramagnetic particles, and generation and acquisition of the chemiluminescent signal. The instrument has the flexibility to operate in random-access or batch mode. The time from application of sample to first result is less than 15 min; throughput is as much as 180 tests per hour.

A simple method of model fitting for adoption data

Traditional models used with adoption data often make strong assumptions concerning the nature of genetic transmission and assortative mating. A simple model is presented which avoids these assumptions. The model is linearized and, thus, has the further advantage that it can be used with standard statistical packages such as LISREL or EQS. The model allows tests of the internal consistency of the data, in addition to tests of the relative strength of genetic and environmental transmission parameters. To illustrate the model, measures of general cognitive ability in parents and their 7-year-old children from the Colorado Adoption Project (CAP) were fit to the model using the LISREL program. This relatively simple model may be expanded to incorporate more complex designs involving multiple measures or siblings. Although the model will not always allow constraints on the parameter estimates in more complex models, it offers a quick, flexible method for initial exploration of adoption data.

Multivariate path analysis of specific cognitive abilities in the Colorado Adoption Project: conditional path model of assortative mating

A multivariate path model of genetic and environmental transmission employing a conditional path representation of assortative mating was fitted to specific cognitive abilities data from the Colorado Adoption Project and evaluated using a maximum-likelihood estimation procedure. In agreement with results obtained from a previous analysis of a smaller data set, significant genetic covariation among the cognitive variables was indicated and evidence for a general genetic factor was found. However, cultural transmission parameters are nonsignificant and environmental correlations among the measures are relatively small.

Genetic and environmental determinants of musical ability in twins

Analyses of musical ability data from the Loehlin and Nichols National Merit Scholarship study are presented. Musical ability is indexed by four measures: interest in a profession in music, performance in school, performance outside of school, and receiving honors in music. These variables pose a challenge for behavior genetic analysis since they do not conform to the assumptions of traditional linear models. For example, there is a dependent relationship between the honors and the performance variables; one cannot obtain honors without performance. Several methods were employed to deal with these relationships, and the following conclusions appeared regardless of the method used. First, twin correlations were always high, ranging from 0.44 to 0.90 in monozygotic (MZ) twins and from 0.34 to 0.83 in dizygotic (DZ) twins. Second, although there was evidence for heritable variation, the effects of common environment were almost always larger than the effects of heredity. Third, marital assortment was not of sufficient magnitude to account for these common environment effects. In the young adults in this sample, musical ability is influenced more by shared family environment than by shared genes.

Big genes, little genes, affective disorder, and anxiety. A commentary

This article offers a brief explanation of the methods used for studying the genetic epidemiology of psychiatric disorder and comments on three articles in this issue of the Archives. Although the methods have had success in detecting genes of major effect for enzymes involved in neurotransmitter synthesis and degradation, they have not produced compelling evidence for a major locus in affective disorder. At the same time, simpler modes of transmission do not fully explain familial data on bipolar disorder or early-onset unipolar disorder. The problem of familial comorbidity of anxiety and depression is discussed, and an illustration is given of how assumptions about psychiatric classification and familial models can obscure the issue of comorbidity.

A general multivariate approach to linear modeling in human genetics

The general linear structural equation model is applied to problems in human genetics where there may be more than one measured phenotype per individual. A modeling convention, termed conditional associations, is developed to extend the general linear model so that it can handle the unique problems in human genetic models that arise from the pairing up of individuals or families under assortment between mates and the assortative placement of adoptees. Formulas are presented to generate expected covariance matrices for assortment or assortative placement on many variables simultaneously. It is demonstrated that all linear models in human genetics can be reduced in form to two fundamental equations. An algorithm is presented that will allow the application of these two equations to linear modeling in human genetics.