Biomedical subjects

R D Abbott

Publications and source records attributed to R D Abbott.

At least 19 recordsLinked to original sources

PubMed2003

Quantification of regional glial fibrillary acidic protein levels in Alzheimer's disease.

OBJECTIVES: Our objectives were to quantify glial fibrillary acidic protein (GFAP) in brains of Alzheimer's disease (AD) cases, and non-AD controls to determine the regions with the most severe gliosis in AD. MATERIAL AND METHODS: In a case control design, we used an enzyme-linked immunosorbent assay (ELISA) to quantify GFAP in frozen brain from four areas of neocortex in 10 AD cases, 10 age-matched controls, and 10 younger controls from the Honolulu-Asia Aging Study autopsy archive. RESULTS: Median age at death was 83.5 years for cases and age-matched controls, and 77 years for younger controls. For the AD cases compared with the age-matched controls, levels of GFAP in occipital (P=0.01), parietal (P=0.028), and temporal lobes (P=0.004) (but not frontal) were significantly higher in the cases. The median GFAP excess in AD cases compared with age matched controls was highest in the temporal lobe. CONCLUSIONS: Regional quantification of GFAP reveals that the glial response is most prominent in the temporal lobe in AD.

Aged↗

PubMed2002

Midlife adiposity and the future risk of Parkinson's disease.

BACKGROUND: Evidence suggests that nigrostriatal system disorders are associated with PD and adiposity. Whether patterns of adiposity coexist or predate clinical PD is unknown. This report examines the relation between midlife adiposity and the risk of PD. METHODS: Measurement of adiposity occurred from 1965 to 1968 in 7,990 men in the Honolulu Heart Program (aged 45 to 68 years and without PD). Adiposity measures included body mass index (BMI), subscapular skinfold thickness (SSF), and triceps skinfold thickness (TSF). Follow-up for incident PD occurred over a 30-year period. RESULTS: During the course of follow-up, PD was observed in 137 men. Among the measures of adiposity, age-adjusted incidence of PD increased threefold from 3.7/10,000 person-years in the bottom quartile of TSF (1 to 5 mm) to 11.1/10,000 person-years in the top quartile (11 to 32 mm, p < 0.001). Effects of TSF on PD were independent of cigarette smoking, coffee consumption, physical activity, daily caloric and fat intake, and the other measures of adiposity (p < 0.001). Whereas rates of PD were lowest in the bottom quartile of BMI and SSF vs higher quartiles, associations with PD were weaker than they were for TSF. The effect of TSF on clinical onset before age 65 years was similar to the effect that was observed in later life. CONCLUSIONS: Increased triceps skinfold thickness measured in midlife is associated with an elevated risk of future PD. Whether patterns of adiposity reflect a unique metabolic pathology in individuals at a high risk of PD warrants further study.

Adipose Tissue↗

PubMed2001

Frequency of bowel movements and the future risk of Parkinson's disease.

BACKGROUND: Constipation is frequent in PD, although its onset in relation to clinical PD has not been well described. Demonstration that constipation can precede clinical PD could provide important clues to understanding disease progression and etiology. The purpose of this report is to examine the association between the frequency of bowel movements and the future risk of PD. METHODS: Information on the frequency of bowel movements was collected from 1971 to 1974 in 6790 men aged 51 to 75 years without PD in the Honolulu Heart Program. Follow-up for incident PD occurred over a 24-year period. RESULTS: Ninety-six men developed PD an average of 12 years into follow-up. Age-adjusted incidence declined consistently from 18.9/10,000 person-years in men with <1 bowel movement/day to 3.8/10,000 person-years in those with >2/day (p = 0.005). After adjustment for age, pack-years of cigarette smoking, coffee consumption, laxative use, jogging, and the intake of fruits, vegetables, and grains, men with <1 bowel movement/day had a 2.7-fold excess risk of PD versus men with 1/day (95% CI: 1.3, 5.5; p = 0.007). The risk of PD in men with <1 bowel movement/day increased to a 4.1-fold excess when compared with men with 2/day (95% CI: 1.7, 9.6; p = 0.001) and to a 4.5-fold excess versus men with >2/day (95% CI: 1.2, 16.9; p = 0.025). CONCLUSIONS: Findings indicate that infrequent bowel movements are associated with an elevated risk of future PD. Further study is needed to determine whether constipation is part of early PD processes or is a marker of susceptibility or environmental factors that may cause PD.

Age Factors↗

PubMed2001

fMRI auditory language differences between dyslexic and able reading children.

During fMRI, dyslexic and control boys completed auditory language tasks (judging whether pairs of real and/or pseudo words rhymed or were real words) in 30 s 'on' conditions alternating with a 30 s 'off' condition (judging whether tone pairs were same). During phonological judgment, dyslexics had more activity than controls in right than left inferior temporal gyrus and in left precentral gyrus. During lexical judgment, dyslexics were less active than controls in bilateral middle frontal gyrus and more active than controls in left orbital frontal cortex. Individual dyslexics were reliably less active than controls in left insula and left inferior temporal gyrus. Dyslexic and control children differ in brain activation during auditory language processing skills that do not require reading.

Acoustic Stimulation↗

PubMed2001

Ankle-brachial blood pressure in elderly men and the risk of stroke: the Honolulu Heart Program.

Although low ankle/brachial blood pressure index (ABI) is a marker of generalized atherosclerosis in the elderly, it has not been identified as a risk factor for stroke. The purpose of this report is to examine the relation between ABI and stroke in elderly men. ABI was measured from 1991 to 1993 in 2767 men aged 71 to 93 years in the Honolulu Heart Program without a history of stroke and coronary heart disease. Subjects were followed for 3 to 6 years for fatal and nonfatal thromboembolic and hemorrhagic stroke. During follow-up, there were 91 strokes. There was an age-adjusted 2-fold excess in men with an ABI < 0.9 (6.0%) versus men with an ABI > or = 0.9 (2.9%, P < 0.01). Thromboembolic events occurred in 4.6% of men with an ABI < 0.9 and in 2.0% in those with an ABI > or = 0.9 (P < 0.01). Hemorrhagic stroke was also more frequent in men with a low ABI (< 0.9) versus a higher ABI (1.9 vs. 0.8%, respectively). After adjusting for other factors, the risk of total and thromboembolic strokes increased with declining ABI (P = 0.019 and P = 0.004, respectively). The relation between ABI and stroke was similar and statistically significant in the presence and absence of diabetes and hypertension (P < 0.05). Findings suggest that ABI is inversely related to the incidence of stroke. Simple measurement of ABI in an outpatient setting could be an important tool for assessing the risk of stroke in the elderly.

Age Distribution↗

PubMed2001

Preadolescent predictors of substance initiation: a test of both the direct and mediated effect of family social control factors on deviant peer associations and substance initiation.

A review of the literature suggests that early substance initiation is related to a variety of negative outcomes, including substance misuse or abuse in adolescence and adulthood. This study examines potentially modifiable predictors of early substance initiation, including both family and peer factors known to influence early initiation. A theoretically derived model of substance initiation was tested using structural equation modeling. Results indicate that both family and peer factors have an impact on early substance initiation when children in this sample were 11 and 12 years old. The model explained 60% of the variance in substance initiation. Prosocial family processes (rules, monitoring, and attachment) had a significant impact on child peer association, decreasing involvement with antisocial peers. These prosocial family processes had a significant negative effect on substance initiation even while modeling the influence of antisocial peers. Implications for drug use prevention practice are discussed.

Catchment Area, Health↗

PubMed2001

beta(2)-Glycoprotein 1-dependent anticardiolipin antibodies and risk of ischemic stroke and myocardial infarction: the honolulu heart program.

BACKGROUND: It has been hypothesized that immunoreactivity to beta(2)-glycoprotein 1 (beta2GP1)-dependent anticardiolipin antibody (aCL), but not beta2GP1-independent aCL, is associated with increased risk of ischemic stroke and myocardial infarction (MI). METHODS: We performed a nested case-control study examining aCL as a risk factor for ischemic stroke and MI by using stored frozen sera obtained from subjects enrolled in the Honolulu Heart Program and followed for up for 20 years. We measured beta2GP1-dependent and beta2GP1-independent aCL and anti-beta2GP1 immunoreactivity in 259 men who developed an ischemic stroke, in 374 men who developed an MI, and in a control group of 1360 men who remained free of both conditions. RESULTS: Only beta2GP1-dependent aCL of the IgG class was significantly associated with both incident ischemic stroke and MI. This association was attenuated in the last 5 years of the 20-year follow-up. For stroke, the risk factor-adjusted relative odds for men with a positive versus a negative beta2GP1-dependent aCL of the IgG class were 2.2 (95% CI 1.5 to 3.4) at 15 years and 1.5 (95% CI 1.0 to 2.3) at 20 years. For MI, the adjusted relative odds were 1.8 (95% CI 1.2 to 2.6) at 15 years and 1.5 (95% CI 1.1 to 2.1) at 20 years. CONCLUSIONS: These data suggest that aCL IgG, particularly the beta2GP1-dependent variety, is an important predictor of future stroke and MI in men.

Age Distribution↗

PubMed2001

Assessing the effects of a school-based intervention on unscheduled school transfers during elementary school.

Raising Healthy Children is a cluster-randomized study of a school-based intervention aimed at preventing problem behaviors among children recruited into the project in the first or second grade of elementary school. Multilevel analysis was used to compare students in intervention and control schools with respect to whether they transferred out of their original schools. Students in intervention schools were less likely to transfer within the first 5 years of the project. A multilevel discrete-time survival model that included both time-varying and contextual variables revealed that the difference in hazard of transfer was greatest in the earlier years of the project.

Child↗

PubMed2001

The social predictors of adolescent alcohol misuse: a test of the social development model.

OBJECTIVE: This study was conducted to investigate the ability of the social development model (SDM) to predict alcohol misuse at age 16 and to investigate the ability of the SDM to mediate the effects of alcohol use at age 14 on alcohol misuse at age 16. METHOD: The sample of 807 (411 males) is from the longitudinal panel of the Seattle Social Development Project which, in 1985, surveyed all consenting fifth-grade students from 18 elementary schools serving high-crime neighborhoods in Seattle, Washington. Alcohol use was measured at age 14, predictors of alcohol misuse were measured at age 15 and alcohol misuse was measured at age 16. Structural equation modeling was used to examine the fit of the model to the data. RESULTS: All factor loadings were highly significant and the measurement model achieved a good fit with the data (Comparative Fit Index [CFI] = 0.93). A second-order structural model fit the data well (CFI = 0.91) and also explained 45% of the variance in alcohol misuse at age 16. The SDM partially and significantly mediated the direct effect of age-14 alcohol use on age-16 alcohol misuse. CONCLUSIONS: The risk and protective processes specified by the SDM serve as potential targets for the prevention or reduction of adolescent alcohol misuse.

Adolescent↗

PubMed2001

Childhood and adolescent predictors of alcohol abuse and dependence in young adulthood.

OBJECTIVE: To provide a comprehensive examination of childhood and adolescent predictors of alcohol abuse and dependence at age 21, theoretically guided by the social development model. METHOD: Data were taken from an ethnically diverse urban sample of 808 students (51% male), surveyed at age 10 and followed prospectively to age 21 in 1996. Potential predictors of alcohol abuse and dependence at age 21 were measured at ages 10, 14 and 16. Relationships between these predictors and alcohol abuse and dependence were examined at each age, to assess changes in their patterns of prediction over time. RESULTS: Strong bonding to school, close parental monitoring of children and clearly defined family rules for behavior, appropriate parental rewards for good behaviors, high level of refusal skills and strong belief in the moral order predicted a lower risk for alcohol abuse and dependence at age 21. Of these, strong bonding to school consistently predicted lower alcohol abuse and dependence from all three ages (10, 14 and 16). By contrast, youths who had a higher risk of alcohol abuse and dependence at age 21 engaged in more problem behaviors, had more opportunities to be involved with antisocial individuals and spent more time with and were more bonded to those individuals, viewed fewer negative consequences from antisocial behaviors and held more favorable views on alcohol use. Of these, prior problem behaviors and antisocial opportunities and involvements at ages 10, 14 and 16 consistently predicted alcohol abuse and dependence at age 21. CONCLUSIONS: These important malleable predictors, identifiable as early as age 10, provide potential intervention targets for the prevention of alcohol abuse and dependence in early adulthood.

Adolescent↗

PubMed2000

Ankle/brachial blood pressure in men >70 years of age and the risk of coronary heart disease.

Low ankle/brachial blood pressure index (ABI) is a marker of generalized atherosclerosis in the elderly, although its association with coronary heart disease (CHD) has not been well established. The purpose of this report is to examine the relation between ABI and the risk of CHD in a sample of elderly men. Findings are based on the ABI that was measured in 2,863 Japanese-American men aged 71 to 93 years at an examination that occurred from 1991 to 1993 in the Honolulu Heart Program. All men were free of total CHD at that time and followed for nonfatal myocardial infarction and death from CHD over a 3- to 6-year period. During follow-up, 186 had a coronary event. Age-adjusted incidence declined significantly from 15.3% in men with an ABI <0.8 to 5.4% in men with an ABI >/=1.0 (p <0.001). The effect of ABI on disease was similar across a variety of risk factor strata, although it seemed strongest in the presence of hypertension and in past and current cigarette smokers. Adjustment for other risk factors failed to diminish the relation between ABI and CHD. We conclude that a low ABI increases the risk of CHD in elderly men. If findings can be extended to other elderly population segments, simple measurement of ABI in an outpatient setting could be an important tool for assessing the risk of CHD in the elderly.

Aged↗

PubMed2000

Serum lipid effects of a high-monounsaturated fat diet based on macadamia nuts.

BACKGROUND: Recent studies have identified potential beneficial effects of eating nuts, most of which have substantial amounts of monounsaturated fats. Macadamia nuts are 75% fat by weight, 80% of which is monounsaturated. OBJECTIVE: To examine variations in serum lipid levels in response to a high-monounsaturated fat diet based on macadamia nuts. METHODS: A randomized crossover trial of three 30-day diets was conducted in 30 volunteers aged 18 to 53 years from a free-living population. Each was fed a "typical American" diet high in saturated fat (37% energy from fat); an American Heart Association Step 1 diet (30% energy from fat); and a macadamia nut-based monounsaturated fat diet (37% energy from fat) in random order. Serum total cholesterol, high-density lipoprotein cholesterol, and triglyceride levels were measured. RESULTS: Mean total cholesterol level after the typical American diet was 5.20 mmol/L (201 mg/dL). After the Step 1 diet and the macadamia nut diet, total cholesterol level was 4.99 mmol/L (193 mg/dL) and 4.95 mmol/L (191 mg/dL), respectively. Low-density lipoprotein cholesterol level was 3.37 mmol/L (130 mg/dL) (typical diet), 3.21 mmol/L (124 mg/dL) (Step 1 diet), and 3.22 mmol/L (125 mg/dL) (macadamia nut diet). High-density lipoprotein cholesterol level was 1.43 mmol/L (55 mg/dL) (typical), 1.34 mmol/L (52 mg/dL) (Step 1), and 1.37 mmol/L (53 mg/dL) (macadamia nut). Lipid values after the Step 1 and macadamia nut diets were significantly different from those after the typical diet (P<.05). CONCLUSIONS: The macadamia nut-based diet high in monounsaturated fat and the moderately low-fat diet both had potentially beneficial effects on cholesterol and low-density lipoprotein cholesterol levels when compared with a typical American diet.

Adolescent↗

PubMed2000

Developmental risk factors for youth violence.

PURPOSE: To replicate earlier research findings on risk factors for youth violence and to explore the effects on violent behavior of constructs shown to increase risk for other problem behaviors, within a developmental frame. METHODS: Data were from the Seattle Social Development Project (SSDP), a prospective study involving a panel of youths followed since 1985. Potential risk factors for violence at age 18 years were measured at ages 10, 14, and 16 years. Bivariate relationships involving risk factor constructs in the individual, family, school, peer and community domains and violence were examined at each age to assess changes in their strength of prediction over time. Attention was also given to the additive strength of increasing numbers of risk factors in the prediction of violence at age 18 years. A final set of analyses explored the extent to which youths were correctly classified as having committed a violent act (or not) at age 18 years on the basis of their overall level of risk at ages 10, 14, and 16 years. RESULTS: At each age, risk factors strongly related to later violence were distributed among the five domains. Ten of 15 risk factors constructs measured at age 10 years were significantly predictive of violence at age 18 years. Twenty of 25 constructs measured at age 14 years and 19 of 21 constructs measured at age 16 years were significantly predictive of later violence. Many constructs predicted violence from more than one developmental point. Hyperactivity (parent rating), low academic performance, peer delinquency, and availability of drugs in the neighborhood predicted violence from ages 10, 14, and 16 years. Analyses of the additive effects of risk factors revealed that youths exposed to multiple risks were notably more likely than others to engage in later violence. The odds for violence of youths exposed to more than five risk factors compared to the odds for violence of youths exposed to fewer than two risk factors at each age were seven times greater at age 10 years, 10 times greater at age 14 years, and nearly 11 times greater at age 16 years. However, despite information gained from all significant risk factors, the overall accuracy in predicting youths who would go on to commit violent acts was limited. CONCLUSIONS: Findings from the study have important implications for preventive intervention programs. Prevention efforts must be comprehensive and developmentally sensitive, responding to large groups or populations exposed to multiple risks.

Adolescent↗

PubMed2000

Early elementary school-aged child attachment to parents: a test of theory and implications for intervention.

Child attachment to parents has been shown in the literature to reduce the likelihood of problem behaviors through enhancing resiliency. Research examining attachment and its relationship to antisocial behavioral outcomes in adolescents has been shaped largely by social control theorists who have theorized that attachment to prosocial others inhibits the expression of antisocial behavioral outcomes (Hirschi, 1969). This paper seeks to expand the literature by investigating the development of child attachment to parent(s) during the early elementary school years as specified theoretically by the social development model (Catalano & Hawkins, 1996). Using structural equation modeling, the results support the theoretical model as proposed by the social development model. School-aged children's attachment to parents can be successfully predicted by constructs outlined in the social development model. Finally, implications for interventions that enhance child attachment to parent(s) are discussed.

Adaptation, Psychological↗

PubMed2000

Exercise-dependent growth hormone release is linked to markers of heightened central adrenergic outflow.

To test the hypothesis that heightened sympathetic outflow precedes and predicts the magnitude of the growth hormone (GH) response to acute exercise (Ex), we studied 10 men [age 26.1 +/- 1.7 (SE) yr] six times in randomly assigned order (control and 5 Ex intensities). During exercise, subjects exercised for 30 min (0900-0930) on each occasion at a single intensity: 25 and 75% of the difference between lactate threshold (LT) and rest (0.25LT, 0.75LT), at LT, and at 25 and 75% of the difference between LT and peak (1.25LT, 1.75LT). Mean values for peak plasma epinephrine (Epi), plasma norepinephrine (NE), and serum GH concentrations were determined [Epi: 328 +/- 93 (SE), 513 +/- 76, 584 +/- 109, 660 +/- 72, and 2,614 +/- 579 pmol/l; NE: 2. 3 +/- 0.2, 3.9 +/- 0.4, 6.9 +/- 1.0, 10.7 +/- 1.6, and 23.9 +/- 3.9 nmol/l; GH: 3.6 +/- 1.5, 6.6 +/- 2.0, 7.0 +/- 2.0, 10.7 +/- 2.4, and 13.7 +/- 2.2 microg/l for 0.25, 0.75, 1.0, 1.25, and 1.75LT, respectively]. In all instances, the time of peak plasma Epi and NE preceded peak GH release. Plasma concentrations of Epi and NE always peaked at 20 min after the onset of Ex, whereas times to peak for GH were 54 +/- 6 (SE), 44 +/- 5, 38 +/- 4, 38 +/- 4, and 37 +/- 2 min after the onset of Ex for 0.25-1.75LT, respectively. ANOVA revealed that intensity of exercise did not affect the foregoing time delay between peak NE or Epi and peak GH (range 17-24 min), with the exception of 0.25LT (P < 0.05). Within-subject linear regression analysis disclosed that, with increasing exercise intensity, change in (Delta) GH was proportionate to both DeltaNE (P = 0.002) and DeltaEpi (P = 0.014). Furthermore, within-subject multiple-regression analysis indicated that the significant GH increment associated with an antecedent rise in NE (P = 0.02) could not be explained by changes in Epi alone (P = 0.77). Our results suggest that exercise intensity and GH release in the human may be coupled mechanistically by central adrenergic activation.

Adult↗

PubMed2000

Catecholamine release, growth hormone secretion, and energy expenditure during exercise vs. recovery in men.

We examined the relationship between energy expenditure (in kcal) and epinephrine (Epi), norepinephrine (NE), and growth hormone (GH) release. Ten men [age, 26 yr; height, 178 cm; weight, 81 kg; O(2) uptake at lactate threshold (LT), 36.3 ml. kg(-1). min(-1); peak O(2) uptake, 49.5 ml. kg(-1). min(-1)] were tested on six randomly ordered occasions [control, 5 exercise: at 25 and 75% of the difference between LT and rest (0.25LT, 0.75LT), at LT, and at 25 and 75% of the difference between LT and peak (1.25LT, 1.75LT) (0900-0930)]. From 0700 to 1300, blood was sampled and assayed for GH, Epi, and NE. Carbohydrate (CHO) expenditure during exercise and fat expenditure during recovery rose proportionately to increasing exercise intensity (P = 0.002). Fat expenditure during exercise and CHO expenditure during recovery were not affected by exercise intensity. The relationship between exercise intensity and CHO expenditure during exercise could not be explained by either Epi (P = 1.00) or NE (P = 0.922), whereas fat expenditure during recovery increased with Epi and GH independently of exercise intensity (P = 0. 028). When Epi and GH were regressed against fat expenditure during recovery, only GH remained statistically significant (P < 0.05). We conclude that a positive relationship exists between exercise intensity and both CHO expenditure during exercise and fat expenditure during recovery and that the increase in fat expenditure during recovery with higher exercise intensities is related to GH release.

Adult↗

PubMed2000

A connectionist approach to making the predictability of English orthography explicit to at-risk beginning readers: evidence for alternative, effective strategies.

A case is made (and illustrated with empirical data with children) for connectionist models that are not only computationally explicit but also instructionally explicit. First-graders (N = 128) at the bottom of their classes in reading (average 11.5 percentile on nationally normed tests) participated in a 3-layer intervention. In the first layer, kept constant for all treatment groups, the alphabet principle was taught, making functional spelling units and alternations explicit. In the second layer, which varied systematically across treatment groups, children received different kinds of tutor modeling in learning a set of words of varying spelling-sound predictability, using different connections between printed and spoken words, singly or in combination. In the third layer, also kept constant, children read and discussed illustrated books. Over the 4-month, 24-lesson intervention, all 7 treatment groups in the second layer improved more in word-specific learning than a contact control group that received phonological and orthographic awareness training without explicit instruction on orthographic-phonological connections. Of these 7, only 3 kinds of explicit modeling (whole word, letter-phoneme, and combined whole word and letter-phoneme) resulted in greater transfer to untrained words than the contact control or the other 4 kinds of explicit modeling. Results are discussed in reference to the controversy over whether dual route or connectionist models best account for the acquisition of reading.

Child↗

PubMed2000

The dynamics of alcohol and marijuana initiation: patterns and predictors of first use in adolescence.

OBJECTIVES: This study, guided by the social development model, examined the dynamic patterns and predictors of alcohol and marijuana use onset. METHODS: Survival analysis and complementary log-log regression were used to model hazard rates and etiology of initiation with time-varying covariates. The sample was derived from a longitudinal study of 808 youth interviewed annually from 10 to 16 years of age and at 18 years of age. RESULTS: Alcohol initiation rose steeply up to the age of 13 years and then increased more gradually; most participants had initiated by 13 years of age. Marijuana initiation showed a different pattern, with more participants initiating after the age of 13 years. CONCLUSIONS: This study showed that: (1) the risk of initiation spans the entire course of adolescent development; (2) young people exposed to others who use substances are at higher risk for early initiation; (3) proactive parents can help delay initiation; and (4) clear family standards and proactive family management are important in delaying alcohol and marijuana use, regardless of how closely bonded a child is to his or her mother.

Adolescent↗