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PubMedDate not supplied

Timing in aging: the role of attention.

This paper questions the issue of attentional capacity in changes in time processing with aging. Performances of young and old subjects were compared in a task involving an attentional sharing between three concurrent estimations of durations (6, 8, or 10 s). Depending upon the experimental condition, the subjects were instructed to simultaneously focus their attention onto one, two, or three target stimuli. The results showed that increased difficulty of the task, that is the increased number of concurrent temporal targets to monitor at a time, led to a greater disruption of timing performance in elderly people than in young adults. Temporal judgments of elderly were less accurate and more variable than those of young adults in the attentional sharing conditions (two or three target durations). The greater sensitivity to interference effects observed in the elderly is discussed in terms of age-related reduction of attentional resources and working-memory deficits.

Adolescent↗

PubMed1999

Adolescent girls' and boys' preferences for provider gender and confidentiality in their health care.

PURPOSE: To assess the influence of demographic variables and health risk status on adolescents' preferences and actual receipt of services regarding provider gender, sharing a physician with parents, and private examinations. METHODS: Data from students participating in the Commonwealth Fund 1997 Survey of the Health of Adolescent Girls were analyzed. The weighted sample included 6748 students from grades 5-12. The influence of demographic variables and health risk status on preferences regarding physician gender, sharing a physician with parents, and parental presence during examinations and on actual physician gender, sharing a physician with parents, and receipt of confidential care was assessed for the 5067 students who indicated that they had a health check-up or physical examination within the past 2 years. Associations were examined using SAS to determine preliminary estimates of significance and correlation coefficients, and SUDAAN to generate proportions and Cochran Mantel-Haenszel Chi-squared values. A multiple logistic regression procedure in SUDAAN was used to assess interaction among demographic variables. RESULTS: Gender, race/ethnicity, grade level, and risk status were associated with preferences regarding provider gender and sharing a physician with parents. 50% of girls preferred a female provider; 48% had no preference. 23% of boys preferred a male provider; 65% had no preference. Most adolescents had no preference regarding whether they shared a physician with parents. Gender, race/ethnicity, grade level, and risk status were associated with preference regarding parental presence during examinations. Most younger girls preferred to have a parent present; most younger boys had no preference. Most older girls and boys preferred private examinations. For actual care situation, most adolescents were cared for by male health providers and did not share a physician with parents. 57% of girls and 66% of boys spoke privately with their health provider. Girls who had a female physician were more likely to have private time than were girls receiving care from a male physician. Gender, grade level, and risk status were associated with having private time with a physician. CONCLUSIONS: Gender was a significant variable in adolescents' preferences regarding health care. Preferences were also influenced by race/ethnicity, grade level, and risk status. A substantial proportion of adolescents, including those involved in health risk activities, report not having private time with their health provider.

Adolescent↗

PubMed2004

Structural analysis of Arabidopsis thaliana nucleoside diphosphate kinase-2 for phytochrome-mediated light signaling.

In plants, nucleoside diphosphate kinases (NDPKs) play a key role in the signaling of both stress and light. However, little is known about the structural elements involved in their function. Of the three NDPKs (NDPK1-NDPK3) expressed in Arabidopsis thaliana, NDPK2 is involved in phytochrome-mediated signal transduction. In this study, we found that the binding of dNDP or NTP to NDPK2 strengthens the interaction significantly between activated phytochrome and NDPK2. To better understand the structural basis of the phytochrome-NDPK2 interaction, we determined the X-ray structures of NDPK1, NDPK2, and dGTP-bound NDPK2 from A.thaliana at 1.8A, 2.6A, and 2.4A, respectively. The structures showed that nucleotide binding caused a slight conformational change in NDPK2 that was confined to helices alphaA and alpha2. This suggests that the presence of nucleotide in the active site and/or the evoked conformational change contributes to the recognition of NDPK2 by activated phytochrome. In vitro binding assays showed that only NDPK2 interacted specifically with the phytochrome and the C-terminal regulatory domain of phytochrome is involved in the interaction. A domain swap experiment between NDPK1 and NDPK2 showed that the variable C-terminal region of NDPK2 is important for the activation by phytochrome. The structure of Arabidopsis NDPK1 and NDPK2 showed that the isoforms share common electrostatic surfaces at the nucleotide-binding site, but the variable C-terminal regions have distinct electrostatic charge distributions. These findings suggest that the binding of nucleotide to NDPK2 plays a regulatory role in phytochrome signaling and that the C-terminal extension of NDPK2 provides a potential binding surface for the specific interaction with phytochromes.

Amino Acid Sequence↗

PubMed1991

Genetic traits related to hypertension and electrolyte metabolism.

The genetic and cultural heritability and intercorrelation of traits related to hypertension have been carried out in 98 Utah pedigrees (2,500 person) and 58 sibships with two or more hypertensive persons (131 hypertensive persons). Although none of these traits has been established as a marker for "sodium-sensitive hypertension," many of them are related at least indirectly to both electrolyte metabolism and risk of hypertension. Significant recessive monogenic effects and high total heritability (52-84%) were found for urinary kallikrein, high fat pattern index, intraerythrocytic sodium, Na-Li countertransport, and ouabain binding sites. Familial correlations more strongly attributable to shared environment than to genetic effects were found for Na,K-ATPase pump activity, intraerythrocytic magnesium, plasma digoxin-like factor, plasma renin activity, and plasma sodium concentration. All anthropometric variables tested showed highly significant genetic heritability with low and insignificant shared family environmental effects. Several of the genetically determined cellular cation tests also correlated with other genetic traits including plasma lipids, anthropometric measurements, and other cellular cation tests. Among hypertensive individuals with familial dyslipidemic hypertension, plasma insulin levels correlated with obesity and lipid abnormalities and with several cellular cation flux tests associated with hypertension.

Adolescent↗

PubMed2005

Interlaboratory comparison of red-cell ATP, 2,3-diphosphoglycerate and haemolysis measurements.

BACKGROUND AND OBJECTIVES: Red blood cell (RBC) storage systems are licensed based on their ability to prevent haemolysis and maintain RBC 24-h in vivo recovery. Preclinical testing includes measurement of RBC ATP as a surrogate for recovery, 2,3-diphosphoglycerate (DPG) as a surrogate for oxygen affinity, and free haemoglobin, which is indicative of red cell lysis. The reproducibility of RBC ATP, DPG and haemolysis measurements between centres was investigated. MATERIALS AND METHODS: Five, 4-day-old leucoreduced AS-1 RBC units were pooled, aliquotted and shipped on ice to 14 laboratories in the USA and European Union (EU). Each laboratory was to sample the bag twice on day 7 and measure RBC ATP, DPG, haemoglobin and haemolysis levels in triplicate on each sample. The variability of results was assessed by using coefficients of variation (CV) and analysis of variance. RESULTS: Measurements were highly reproducible at the individual sites. Between sites, the CV was 16% for ATP, 35% for DPG, 2% for total haemoglobin and 54% for haemolysis. For ATP and total haemoglobin, 94 and 80% of the variance in measurements was contributed by differences between sites, and more than 80% of the variance for DPG and haemolysis measurements came from markedly discordant results from three sites and one site, respectively. In descending order, mathematical errors, unvalidated analytical methods, a lack of shared standards and fluid handling errors contributed to the variability in measurements from different sites. CONCLUSIONS: While the methods used by laboratories engaged in RBC storage system clinical trials demonstrated good precision, differences in results between laboratories may hinder comparative analysis. Efforts to improve performance should focus on developing robust methods, especially for measuring RBC ATP.

2,3-Diphosphoglycerate↗

PubMed1995

Patterns of injecting and sharing in a Scottish prison.

Although the potential for prisons to act as the setting for HIV transmission has been recognised, there is an enduring lack of knowledge in this area. Data are presented on patterns of injecting and sharing in Edinburgh prison (Scotland), 1993-1994. There was a relatively low level of injecting in Edinburgh prison during this period, with 13% (8/60) of a sample of drug users having injected at some point during their current sentence. The majority (6/8) of those who had injected had shared injecting equipment. Where sharing took place, the level of HIV risk was variable, but would have been higher had cleaning fluids not been available within the prison, or had they not been used by sharers. The implications of this study for drug service provision in prisons is discussed.

Adult↗

PubMed2004

Isolation of monotreme T-cell receptor alpha and beta chains.

Monotremes are an ancient mammalian lineage that last shared a common ancestor with the marsupial and eutherian (placental) mammals about 170 million years ago. Characterization of their immune genes is allowing us to gain insights into the evolutionary processes that lead to the 'mammalian' immune response. Here we describe the characterization of the first cDNA clones encoding T-cell receptors from a monotreme. Two TCR alpha-chain cDNAs ( TCRA) from the short-beaked echidna, Tachyglossus aculeatus, containing complete variable, joining and constant regions were isolated. The echidna TCRA constant region shares approximately 37% amino acid identity with other mammalian TCRA constant region sequences. The two variable regions belong to the TCRAV group C, which also contains V genes from humans, mice, cattle and chickens. One echidna TCR beta-chain cDNA ( TCRB) containing the entire constant region was isolated and sequenced. It shares about 63% identity with other mammalian TCRB constant region sequences. The echidna TCRBV belongs to TCRBV group A, which also contains V genes from various eutherian species. Southern blot analysis indicates that, like in other mammalian species, there is only one TCRA constant region copy in the echidna genome, but at least two TCRB constant regions.

Amino Acid Sequence↗

PubMedDate not supplied

Late onset of discordant growth in a monochorionic twin pregnancy: vascular anastomoses determine fetal growth pattern and not placental sharing.

Twin-twin transfusion syndrome in monochorionic twin pregnancies has a complex and variable clinical presentation. We present the first documented case where two unidirectional arteriovenous anastomoses connecting the donor twin's larger with the recipient's smaller placental part produce late onset of discordant growth and subsequent twin-twin transfusion syndrome. We conclude that the haemodynamic effects of the anastomoses caused the observed discordant fetal development and not the unequally shared placenta.

Adult↗

PubMed2003

Familial aggregation of abnormal methylation of parental alleles at the IGF2/H19 and IGF2R differentially methylated regions.

Loss of imprinting (LOI) has been observed in many types of human tumors and may be a predisposing event in some colon cancers. LOI is strongly associated with alteration of normal DNA methylation patterns in differentially methylated regions (DMRs) of affected loci but it is not known whether LOI is caused by stochastic, environmental or genetic factors. We have developed a simple, quantitative assay for measurement of allelic methylation ratios based on methylation-sensitive restriction endonuclease digestion of genomic DNA and 'hot-stop' PCR. We examined allelic methylation ratios at DMRs within the IGF2/H19- and IGF2R-loci in a panel of 48 three-generation families. We observed familial clustering of individuals with abnormal methylation ratios at the IGF2/H19 DMR, as well as stability of this trait over a period of nearly two decades, consistent with the possibility that constitutional LOI at this locus is due largely to genetic factors. At the IGF2R DMR, we observed more variability in the allelic methylation ratios over time but also observed familial clustering of abnormal methylation ratios. Overall, our observations at IGF2R suggest that shared genetic factors are responsible for a major fraction of inter-individual variability in parental origin-dependent epigenetic modifications. However, temporal changes also occur in isolated cases, as well as within multiple individuals in the same family, indicating that environmental factors may also play a role.

Alleles↗

PubMed2005

Clinical and molecular analysis of a four-generation Chinese family with aminoglycoside-induced and nonsyndromic hearing loss associated with the mitochondrial 12S rRNA C1494T mutation.

We report here the clinical, genetic, and molecular characterization of a four-generation Chinese family with aminoglycoside-induced and nonsyndromic hearing loss. Five of nine matrilineal relatives had aminoglycoside-induced hearing loss. These matrilineal relatives exhibited variable severity and audiometric configuration of hearing impairment, despite sharing some common features: being bilateral and having sensorineural hearing impairment. Sequence analysis of mitochondrial DNA (mtDNA) in the pedigree identified 16 variants and the homoplasmic 12S rRNA C1494T mutation, which was associated with hearing loss in the other large Chinese family. In fact, the occurrence of the C1494T mutation in these genetically unrelated pedigrees affected by hearing impairment strongly indicated that this mutation is involved in the pathogenesis of aminoglycoside-induced and nonsyndromic hearing loss. However, incomplete penetrance of hearing loss indicated that the C1494T mutation itself is not sufficient to produce a clinical phenotype but requires the involvement of modifier factors for the phenotypic expression. Those mtDNA variants, showing no evolutional conservation, may not have a potential modifying role in the pathogenesis of the C1494T mutation. However, nuclear background seems to contribute to the phenotypic variability of matrilineal relatives in this family. Furthermore, aminoglycosides modulate the expressivity and penetrance of deafness associated with the C1494T mutation in this family.

Adolescent↗

PubMed1992

Shared HLA class II-associated genetic susceptibility and resistance, related to the HLA-DQB1 gene, in IgA deficiency and common variable immunodeficiency.

Most cases of selective IgA deficiency (IgA-D) and common variable immunodeficiency (CVID) occur sporadically. However, familial clustering is not uncommon, and the two disorders can occur within the same family. We have previously described positive associations with three DR-DQ haplotypes as well as a strong negative association with DRw15,DQw6,Dw2 in IgA-D. Different amino acids at position 57 of the HLA-DQ beta chain were found to be related to susceptibility and resistance to IgA-D. Now we have found identical, although somewhat weaker, positive and negative DR-DQ associations in a large group of CVID patients (n = 86), as well as the same associations with codon 57 of the DQB1 gene. In addition, we have confirmed our earlier observations in an independent group of IgA-D individuals (n = 69), and in sib-pair analysis we have found linkage of the genetic susceptibility to IgA-D to the HLA class II region. In IgA-D individuals not carrying the three overrepresented DR-DQ haplotypes, the same positive association with a non-aspartic acid residue at position 57 of the HLA-DQ beta chain was seen. The previously reported associations with deletions of the HLA class III genes C4A (fourth component of complement) and CYP21P (steroid 21-hydroxylase pseudogene) were, in our groups of immunodeficient individuals, statistically secondary to the association with the DQB1 allele 0201. The shared HLA class II associations in the two humoral immunodeficiencies support the hypothesis that IgA-D and CVID are related disorders. Disease susceptibility and resistance are most closely associated with a gene(s) within the DR-DQ region, alleles of the DQB1 locus being candidate genes.

Alleles↗

PubMed2002

NF1 mutations and molecular testing.

Neurofibromatosis 1 is a progressive autosomal dominant condition caused by mutations in the NF1 gene on chromosome 17. The condition shows clinical variable expressivity, with varying features even between family members who share the same mutation. Furthermore, it is impossible to precisely predict the severity and course of the condition, a source of frustration for families and physicians. Neurofibromatosis 1 is also heterogeneous at the mutation level, with more than 300 independent mutations having been reported in this gene. The mutation data have accumulated slowly owing to the variability of the mutation types and the size and complexity of the gene. This is also reflected in the lack of a simple, inexpensive, highly accurate DNA-based test for neurofibromatosis 1 at present. This article reviews current NF1 mutation spectrum and testing, discussing and illustrating mutation mechanisms and pathogenetic effects, as well as factors affecting DNA testing and interpretation/diagnosis.

Child↗

PubMed1997

The effects of right-hemisphere brain damage on patients' use of terms of personal reference.

Successful communication depends on social as well as linguistic factors. In conversation, for example, a speaker must often refer to another person. Choosing an appropriate term of personal reference requires a speaker to consider several features of the discourse context, including properties of the persons being referred to and what knowledge is shared between the speaker and his or her addressee. In a pair of similar studies, we examined how right-hemisphere brain-damaged (RHD) patients and nonbrain-damaged control subjects use these different kinds of information in choosing formal (e.g., "Mr. Harding") versus informal ("Oliver") terms of reference for an absent third person. Stimulus vignettes manipulated three variables: the occupational status of the referent, the speaker's familiarity with the referent (i.e., the degree to which the speaker and referent were personally acquainted), and the addressee's familiarity (i.e., the degree to which the addressee and referent were personally acquainted). Relative to the control subjects, the RHD patients showed decreased use of both familiarity variables when choosing formal over informal labels, but apparently preserved sensitivity to the status variable. These results suggest how decreased use of the knowledge shared between a speaker and addressee disrupts RHD patients' discourse and thus contributes to these patients' aberrant interpersonal behavior. In addition. In addition, the results from the second study demonstrated an asymmetry in how female versus male subjects responded to the status manipulation.

Aged↗

PubMed2006

Correlations of functional capacity and neuropsychological performance in older patients with schizophrenia: evidence for specificity of relationships?

BACKGROUND: Neuropsychological (NP) performance is a consistent correlate of everyday functioning in schizophrenia, but it is unclear whether relationships between individual NP ability areas and domains of everyday functioning are general or specific. Assessments of real-world everyday functioning may be influenced by environmental and social factors (e.g., social security, disability status, opportunities and restrictions in living situations). This study examined the specificity of the relationships between different NP abilities and performance-based measures of social and living skills. METHODS: 181 ambulatory older (age>50) patients with schizophrenia were examined with NP tests measuring episodic and working memory, executive functioning, verbal fluency, and processing speed. All subjects performed tasks examining social (Social Skills Performance Assessment: SSPA) and everyday living (UCSD Performance Based Skills Assessment: UPSA) skills. RESULTS: Using canonical analysis, the NP variables were used to predict the functional capacity measures. The analysis found that 37% of the variance in the functional capacity and NP measures was shared, X(2) (54)=106.29, p<.001. Two canonical roots described the cognitive variables and the roots were differentially associated with everyday living and social skills. The root loading on processing speed, episodic memory, and executive functions were associated with UPSA scores, while the root loading on working and episodic memory and verbal fluency were associated most strongly with social competence. IMPLICATIONS: Social and everyday living skills deficits in patients with schizophrenia may reflect generally independent domains of functional outcome, linked through cognitive performance. The data suggest that somewhat different cognitive processes are associated with these two domains of functional capacity, although there appears to be some overlap, which may be due to the nature of the NP tests employed.

Activities of Daily Living↗

PubMed1983

Competition between non-profit and for-profit health insurers.

This study investigates the effects of tax, regulatory, and reimbursement policies and other factors exogenous to the health insurance market on the relative price (to commercial insurers) paid by Blue Cross plans for hospital care, their administrative expense and accounting profits, premiums, and ultimately Blue Cross market share. We specify and estimate a simultaneous equation model to assess interrelationships among these variables. We conclude that premium tax advantages enjoyed by the Blues have virtually no effect on the Blues' premiums or their market shares. A Blue Cross plans' market share has a positive effect on the discount it obtains from hospitals as does coverage of Blue Shield charges by a state-mandated rate-setting plan. An upper bound on the effect on the Blue Cross market share of covering Blue Cross under rate-setting but excluding the commercials from such coverage is seven percentage points. Tests for administrative slack in the operation of Blue Cross plans yield mixed results.

Blue Cross Blue Shield Insurance Plans↗

PubMed1993

Sharing MLM's: an experiment between Columbia-Presbyterian and LDS Hospital.

The use of Arden syntax for development of shareable medical logic modules (MLM's) has developed as an ASTM standard. To test the feasibility of sharing MLM's between institutions a study was conducted between Columbia-Presbyterian Medical Center and LDS Hospital. In this study seven MLM's clinically executing at Columbia-Presbyterian were used to test the sharing potential of the Arden syntax. The study was limited to measuring the modifications necessary to make executable at LDS Hospital the shared MLM's. Because of the site specific nature of the data variables, multiple modifications were required. Three classes of modifications were necessary. The simplest involved only data variable mappings. The other classes required either minor modifications to the logic or relatively major modifications. Over 50% of the modifications were in the minor or major classes. While the sharing of decision logic was possible and facilitated by the use of the MLM's at the two sites, the absence of standard medical vocabularies limited the utility of the MLM as a mechanism for directly sharing medical knowledge.

Hospital Information Systems↗

PubMed2006

Social support and HIV-related injection risk among Puerto Rican migrant and nonmigrant injection drug users recruited in New York City.

This study compared the associations between social support and HIV injection risk among Puerto Rican migrant (n = 221) and nonmigrant (n = 340) injection drug users in New York City. Practical and emotional support scales were developed from 8 items and examined by migrant status as predictors of risk. Bivariate and regression analysis were conducted with drug shooting gallery use, sharing needles, paraphernalia, and number of monthly injections as dependent variables. Migrants had lower emotional (2.82 vs. 3.19, p = .002) and practical (1.87 vs. 2.05; p = .051) support than nonmigrants. Controlling for age, sex and homelessness, emotional support was negatively associated to injection frequency and (standardized coefficient = -.168, p = .020) gallery use (adjusted odds ration [AOR] = .76, confidence interval [CI] = .62-.94, p = .011) among migrants and to an almost two fold increase in sharing syringes (AOR= 1.87, CI = 1.02-3.43; p = .041) among nonmigrants. The findings suggest that though migrants have less support than nonmigrants do, their support reduces risk and thus their likelihood of injection-related HIV infection.

Adult↗

PubMed1987

Partitioning the variability of fasting plasma glucose levels in pedigrees. Genetic and environmental factors.

Fasting plasma glucose measurements made in 1972-1977 on normoglycemic individuals in three-generation Caucasian pedigrees from Rochester, Minnesota were analyzed. The authors determined the contributions of polygenic loci and environmental factors to fasting plasma glucose variability in these pedigrees. To that end, fasting plasma glucose measurements were normalized by an inverse normal scores transformation and then regressed separately for males and females on measured concomitants including age, body mass index (weight/height2), season of measurement, sex hormone use, and diuretic use. The authors found that 27.7% of the variability in normalized fasting plasma glucose in these pedigrees is explained by these measured concomitants. Subsequent variance components analysis suggested that unmeasured polygenic loci and unmeasured shared environmental factors together account for at least an additional 36.7% of the variability in normalized fasting plasma glucose, with genes alone accounting for at least 27.3%. These results are consistent with the known familiality of diabetes, for which fasting plasma glucose level is an important predictor. Further, these familial factors provide an explanation for at least half the variability in normalized fasting plasma glucose which remains after regression on known concomitants.

Adolescent↗