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Biomedical subjects

Charles C Berry

Publications and source records attributed to Charles C Berry.

26 records · Page 2Linked to original sources
PubMed2002

The extent of linkage disequilibrium in Arabidopsis thaliana.

Linkage disequilibrium (LD), the nonrandom occurrence of alleles in haplotypes, has long been of interest to population geneticists. Recently, the rapidly increasing availability of genomic polymorphism data has fueled interest in LD as a tool for fine-scale mapping, in particular for human disease loci. The chromosomal extent of LD is crucial in this context, because it determines how dense a map must be for associations to be detected and, conversely, limits how finely loci may be mapped. Arabidopsis thaliana is expected to harbor unusually extensive LD because of its high degree of selfing. Several polymorphism studies have found very strong LD within individual loci, but also evidence of some recombination. Here we investigate the pattern of LD on a genomic scale and show that in global samples, LD decays within approximately 1 cM, or 250 kb. We also show that LD in local populations may be much stronger than that of global populations, presumably as a result of founder events. The combination of a relatively high level of polymorphism and extensive haplotype structure bodes well for developing a genome-wide LD map in A. thaliana.

Arabidopsis↗
PubMed2002

Tracking dietary intake in white and Mexican-American children from age 4 to 12 years.

OBJECTIVE: To examine the tracking (ie, the stability over time) of dietary intake in Mexican-American and white children aged 4 to 12 years. SUBJECTS: Children 4 years of age (n=351) were assessed at baseline and 65% (n=228) completed the 8-year study. DESIGN: Cardiovascular disease-related dietary intake was defined as energy, percent of energy from fat, and sodium (mg/1,000 kcal). From age 4 to 7 years, a modified 24-hour recall with observation of lunch and dinner and interview of the primary food preparer for unobserved foods was used to describe dietary intake. For children aged 11 to 12 years, a standardized 24-hour recall was used. STATISTICAL ANALYSES: A mixed effects model that adjusted for sex, ethnicity, and measurement wave allowed for separation of shorter-term variations in diet from more stable ("between subject") variations. Extent of between-subject variance is an indication of tracking. RESULTS: From age 4 to age 7, there were statistically significant between-subject variance components for energy (P<.00001), percent of energy from fat (P<.00001), and sodium per 1,000 kcals (P<.001); for ages 11 and 12, energy intake was significant (P<.00001). There were no significant associations for dietary intake from age 4 to 12 years. CONCLUSIONS/APPLICATIONS: It seems that dietary intakes are stable over short periods and at earlier ages compared with longer intervals and later ages. Nutrition interventions are needed in childhood and throughout adolescence.

Age Factors↗
PubMed2002

Independent contribution of psychological factors to fibrin turnover in subjects with sleep apnoea and/or systemic hypertension.

By promoting atherosclerosis and thrombosis, a blood-clotting diathesis could contribute to excess cardiovascular morbidity and mortality in patients with systemic hypertension and/or obstructive sleep apnoea. Since psychological states affect haemostatic activity, we wondered about the contribution of behavioural factors to a hypercoagulable state in subjects with increased risk of cardiovascular disease. To tease apart the potential additive nature of cardiovascular disease risk, we examined four patient groups - hypertensives and normotensives, with and without sleep apnoea. The procoagulant molecules thrombin-antithrombin III complex, fibrin D-dimer and von Willebrand factor antigen were measured in 88 subjects (mean age 47 years; range 32-64 years) who underwent full polysomnography. Subjects completed the Center for Epidemiological Studies - Depression (CES-D) Scale, the Cook-Medley (CM) Hostility Scale, and the Profile of Mood States (POMS). Sleep apnoea, hypertension status, age, body mass index and psychological variables (CES-D, CM Stress, and POMS Vigour-Activity) together explained 29% of the variance in D-dimer, a marker of fibrin turnover ( r (2)=0.29, P =0.001). CES-D, CM Stress and POMS Vigour-Activity explained 17% of this variance even after controlling for sleep apnoea, hypertension status, age and body mass index (Delta r (2)=0.17, P =0.001). Thrombin-antithrombin III complex and von Willebrand factor were not significantly related to psychological variables, but this may reflect limited statistical power. Thus psychological factors are independently associated with D-dimer and explain as much of its variance as do traditional correlates (hypertension, sleep apnoea, age and body mass index). These results may provide a rationale for linking behavioural aspects with cardiovascular events.

Adult↗
PubMed2002

Childhood movement skills: predictors of physical activity in Anglo American and Mexican American adolescents?

We assessed the relationship between young children's movement skills and their physical activity in early adolescence. Balance, agility, eye-hand coordination, and skinfold thicknesses in 207 Mexican American and Anglo American children (104 boys, 103 girls) were measured at ages 4, 5, and 6 years. Habitual physical activity was assessed at the age of 12 years by two interviewer-administered 7-day recalls. Ethnic differences in movement skills were not found. Young girls were better at jumping and balancing, and young boys were better at catching. Tracking of skills was low, and children's early childhood skills were not related to their physical activity 6 years later. Further studies involving additional movement skills and other populations are recommended to determine if enhanced movement skills in children promote subsequent physical activity.

Child, Preschool↗
PubMed2002

Quantitative trait loci controlling light and hormone response in two accessions of Arabidopsis thaliana.

We have mapped quantitative trait loci (QTL) responsible for natural variation in light and hormone response between the Cape Verde Islands (Cvi) and Landsberg erecta (Ler) accessions of Arabidopsis thaliana using recombinant inbred lines (RILs). Hypocotyl length was measured in four light environments: white, blue, red, and far-red light and in the dark. In addition, white light plus gibberellin (GA) and dark plus the brassinosteroid biosynthesis inhibitor brassinazole (BRZ) were used to detect hormone effects. Twelve QTL were identified that map to loci not previously known to affect light response, as well as loci where candidate genes have been identified from known mutations. Some QTL act in all environments while others show genotype-by-environment interaction. A global threshold was established to identify a significant epistatic interaction between two loci that have few main effects of their own. LIGHT1, a major QTL, has been confirmed in a near isogenic line (NIL) and maps to a new locus with effects in all light environments. The erecta mutation can explain the effect of the HYP2 QTL in the blue, BRZ, and dark environments, but not in far-red. LIGHT2, also confirmed in an NIL, has effects in white and red light and shows interaction with GA. The phenotype and map position of LIGHT2 suggest the photoreceptor PHYB as a candidate gene. Natural variation in light and hormone response thus defines both new genes and known genes that control light response in wild accessions.

Arabidopsis↗
PubMed2002

Home environmental influences on children's television watching from early to middle childhood.

Identifying correlates of children's television (TV) watching could help identify strategies to reduce children's TV watching and impact children's weight status. Children's TV time and home environment factors were assessed longitudinally among 169 families with children followed from 6 to 12 years of age. TV watching increased with age, as did the number of in-home TVs and the presence of videocassette recorders (VCRs), the frequency of meal eating while watching TV, and the percentage of children with bedroom TVs. Greater meal eating while watching TV was consistently related to overall TV watching and increases in TV watching over time. The number of in-home TVs and the presence of a bedroom TV were less consistent correlates. TV watching was related to weight status when children were younger, and when children were older, more than 2 hours of TV daily was a risk factor for higher weight. Modifying TV access, particularly by reducing the frequency of meals eaten while watching TV, could promote lower children's TV watching and adiposity.

Body Weight↗
PubMed2002

Comparison of two transducers for color Doppler imaging of the retrobulbar vessels.

PURPOSE: To compare blood flow velocity measurements obtained with two different linear probes (7.5 MHz and 12 MHz). MATERIALS AND METHODS: CDI measurements were performed in 31 eyes of 19 individuals with a 12 MHz and a 7.5 MHz probe. Measurements were taken in the ophthalmic artery (OA), central retinal artery (CRA), temporal short posterior ciliary arteries (TSPCA), and nasal short posterior ciliary arteries (NSPCA). With each probe, three measurements of each vessel were obtained, and end-diastolic velocity (EDV), peak systolic velocity (PSV), and resistance index (RI) were calculated. RESULTS: For EDV, the variation among replicates with the 7.5 MHz probe was between 13.99% and 19.51% and with the 12 MHz probe between 15.40% and 23.17%. For PSV, the variation among replicates was between 5.16% and 9.98% and between 6.58% and 10.71%, respectively with each probe. For RI, the variation among the replicates was between 3.10% and 8.97% and between 3.93% and 10.16%, respectively with each probe. The variation between probes was between 15.02% and 23.07% for EDV, between 10.72% and 13.24% for PSV, and between 4.27% and 6.05% for RI. The difference between estimated means was only significant for EDV in the TSPCA (P = 0.019), PSV in the TSPCA (P = 0.0002), as well as NSPCA (P = 0.003) and RI in the CRA (P < 0.001) and NSPCA (P < 0.044). CONCLUSION: The observed variation among three measurements is similar with both the 7.5 MHz and the 12 MHz probes. However, the 7.5 MHz probe tends to measure slightly higher values for some parameters.

Adult↗