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Biomedical subjects

G J Duncan

Publications and source records attributed to G J Duncan.

At least 19 recordsLinked to original sources
PubMed2001

Sibling, peer, neighbor, and schoolmate correlations as indicators of the importance of context for adolescent development.

We use nationally representative data to calculate correlations in achievement and delinquency between genetically differentiated siblings within a family, between peers as defined by adolescents' "best friend" nominations, between schoolmates living in the same neighborhood, and between grademates within a school. We find the largest correlations between siblings, especially identical twins. Grademate and neighbor correlations are small. Peer-based correlations are considerably larger than grademate and neighbor correlations but not larger than most sibling correlations. The data suggest that family-based factors are several times more powerful than neighborhood and school contexts in affecting adolescents' achievement and behavior.

Adolescent↗
PubMed1999

Rat metallothionein-2 contains N(alpha)-acetylated and unacetylated isoforms.

Mammalian metallothioneins (MT), are characteristically N(alpha)-acetylated and the presence of an unblocked N-terminus has not previously been reported. On-line capillary electrophoresis-electrospray mass spectrometry of hepatic MT-2 from rats injected with zinc revealed two isoforms differing by a mass equivalent to that of a single acetyl group. The lower mass component constituted > 20% of total MT-2 protein and both MT-2 isoforms were separated by reversed-phase high-performance liquid chromatography. The identity of each fraction was confirmed by matrix-assisted laser desorption ionisation mass spectrometry, and amino acid analysis and N-terminal sequencing revealed that the lower mass isoform was unblocked at the N-terminus and had an amino acid composition and sequence which is characteristic of rat MT-2. Thus the complementary techniques of mass spectrometry and N-terminal sequencing demonstrated conclusively that purified MT-2 from zinc-treated rats contains an unacetylated isoform. We propose that the cotranslational acetylation of rat MT-2 may under some circumstances be inefficient compared to that in other nonrodent species, where we have detected only trace levels of unacetylated MT isoforms.

Acetylation↗
PubMed1999

Gender and the socioeconomic gradient in mortality.

Despite considerable evidence documenting a strong and persistent relationship between socioeconomic position and mortality, recent research suggests that this association may be weaker among women. In our examination of gender differences in the socioeconomic gradient in mortality, we argue that this inconsistency arises from the failure to consider the ways in which gender is a fundamental constituent of socioeconomic position. The data used are from the Panel Study of Income Dynamics. Respondents, including all household heads and their partners, aged 29 years and older in 1972 (N = 5,665; 56% female), were followed until 1991, death, or attrition. Discrete time event history analysis was used to examine the predictors of death between 1972 and 1991. Of the key socioeconomic predictors, years of education was measured at baseline, while earned income was a time-varying covariate. We find no gender differences in the effect of respondents' own socioeconomic positions on their mortality risk. However, increasing spousal income raises men's odds of dying, while the opposite is true for women. Our results raise questions about the prevailing view that the socioeconomic gradient in mortality is weaker among women. Moreover, gender differences in the effects of spousal earnings on mortality risk suggest that their labor market rewards have fundamentally different meanings for women and men.

Adult↗
PubMed1998

Macro-to-micro links in the relation between income inequality and mortality.

A growing literature points to links between income inequality and mortality. Any examination of the link should distinguish, both theoretically and empirically, between shifts in inequality that result from changes in the bottom and top of the income distribution. When state-level data from the U.S. censuses of 1980 and 1990 were used to measure differences in mortality, the results indicated that inequality measures reflecting depth of poverty show stronger correlations with mortality than do inequality measures reflecting heights of affluence. In addition, longitudinal data from the Panel Study of Income Dynamics were used to related state-level inequality measures to individual-level data on mortality. This comparison revealed significant associations between degree of income inequality in state of residence and individual risk of death only for nonelderly individuals with middle-class incomes in 1990.

Health Status Indicators↗
PubMed1998

Kienbock's disease: treatment by implantation of vascular pedicle and bone grafting.

Eleven patients with stage II and IIIA Kienbock's disease treated with vascular pedicle implantation and bone grafting were reviewed to determine the long term efficacy of the procedure. Eight wrists had a negative ulnar variance and three wrists had a neutral ulnar variance. The procedure involved implanting the second dorsal metacarpal artery and its venae commitantes into a hole made in the lunate through a dorsal approach. Cancellous bone graft from the dorsal aspect of the distal radius was loosely packed in the hole to secure the pedicle. Follow-up was from 37 to 140 months with an average of six years. Nine patients had significant long term pain relief, improved function, and required no additional procedures. In two patients, continued pain necessitated proximal row carpectomy at two and 4.5 years postoperatively. Ten of the eleven patients had no worsening of their radiographic staging, but in no patient was the architecture of the lunate restored. There were no complications. The results are promising enough to recommend consideration of this procedure in the early stages of Kienbock's disease in patients with a neutral or negative ulnar variance.

Adult↗
PubMed1997

Income dynamics and adult mortality in the United States, 1972 through 1989.

OBJECTIVES: The aim of this study was to examine relationships between income and mortality, focusing on the predictive utility of single-year and multiyear measures of income, the shape of the income gradient in mortality, trends in this gradient over time, the impact of income change on mortality, and the joint effects of income and age, race, and sex on mortality risk. METHODS: Data were taken from the Panel Study of Income Dynamics for the years 1968 through 1989. Fourteen 10-year panels were constructed in which predictors were measured over the first 5 years and vital status over the subsequent 5 years. The panels were pooled and logistic regression was used in the analysis. RESULTS: Income level was a strong predictor of mortality, especially for persons under the age of 65 years. Persistent low income was particularly consequential for mortality. Income instability was also important among middle-income individuals. Single-year and multiyear income measures had comparable predictive power. All effects persisted after adjustment for education and initial health status. CONCLUSIONS: The issues of low income and income instability should be addressed in population health policy.

Black or African American↗
PubMed1996

Income dynamics and health.

The focus of this article is the economic dimension of socioeconomic status as it relates to health. In contrast to the assumptions of many life cycle models, the author finds household income to be quite volatile for many families, even during periods of macroeconomic growth. Income inequality has increased dramatically in the last 20 years. Studies relating various measures of health (e.g., low birth weight; cognitive development, stunting, wasting in early childhood; mortality in later adult years) to longitudinal measures of family income often find quite powerful effects of income, even after controlling for correlated aspects of socioeconomic status and baseline health status. The author discusses strategies for modeling income effects.

Adolescent↗
PubMed1996

Ethnic differences in children's intelligence test scores: role of economic deprivation, home environment, and maternal characteristics.

We examine differences in intelligence test scores of black and white 5-year-olds. The Infant Health and Development Program data set includes 483 low birthweight premature children who were assessed with the Wechsler Preschool and Primary Scale of Intelligence. These children had been followed from birth, with data on neighborhood and family poverty, family structure, family resources, maternal characteristics, and home environment collected over the first 5 years of life. Black children's IQ scores were 1 SD lower than those of white children. Adjustments for ethnic differences in poverty reduced the ethnic differential by 52%. Adjustments for maternal education and whether the head of household was female did not reduce the ethnic difference further. However, differences in home environment reduced the ethnic differential by an additional 28%. Adjustments for economic and social differences in the lives of black and white children all but eliminate differences in the IQ scores between these two groups.

Black or African American↗
PubMed1996

Economic mobility of young workers in the 1970s and 1980s.

This paper uses longitudinal data to estimate cohort changes in the earnings trajectories of young adult males. Levels of earnings are uniformly lower for male workers turning 21 between 1980 and 1991 than in 1970-1979, although rates of earnings growth are roughly comparable. Among males turning 21 before 1980, six in 10 (60%) of all men and seven in 10 (71%) college-educated men attained earnings levels by age 30 that were at least twice the poverty level. Corresponding fractions for workers turning 21 between 1980 and 1991 were considerably lower (42% and 56%). Recent cohorts from all demographic subgroups appeared to have more difficulty than older cohorts in attaining middle-class earnings.

Adult↗
PubMed1995

Entrapment of the palmar cutaneous branch of the median nerve by a normal palmaris longus tendon.

An anomalous course of the palmar cutaneous branch of the median nerve was noted in a patient with symptoms of compression of the median nerve and its palmar cutaneous branch at the wrist level. The palmar cutaneous branch of the nerve pierced the tendon of a normal palmaris longus muscle near its insertion. Decompression of the median nerve and its palmar cutaneous branch was performed, with complete relief of symptoms.

Adult↗
PubMed1995

One hundred years of automobile-induced orthopedic injuries.

As the automobile has evolved over its first 100 years, many changes have improved its safety and have resulted in lower fatality rates. To a great extent, physicians have provided the thrust for these improvements. Now, as more people survive automobile accidents, injuries to the musculoskeletal system take on importance as causes of individual disability and social cost. The patterns of automobile-induced orthopedic injuries continue to change. This article reviews the first 100 years of these injury patterns and relates their occurrence to specific automobile design features and oversights. Because any one automobile accident is likely to injury only a few people at most, trends and patterns are much more difficult to ascertain than for mass transit vehicular accidents. For this reason, physician awareness of contemporary injury patterns is the first step toward safer automobile design.

Accidents, Traffic↗
PubMed1994

Sharing prosperity across the age distribution: a comparison of the United States and Germany in the 1980s.

Using six waves of data from the Panel Study of Income Dynamics and the German Socio-Economic Panel we compare the relative economic well-being of Americans and Germans in the 1980s. Economic growth during the 1980s substantially improved the economic well-being of the average person in the both the United States and Germany. But the rewards were disproportionately distributed across age and gender. In both countries, the family incomes of the very old, the very young and women were lower and grew more slowly than did the income of other families. Social security policy in Germany was more successful than American policy in providing income security in old age. But, despite massive social security programs in both countries, older women were still the most vulnerable members of society, in part because of a substantial drop in the level of social insurance they received following the death of their spouse.

Adolescent↗
PubMed1994

Validation in sheep of the doubly labeled water method for estimating CO2 production.

Carbon dioxide production (rCO2) was estimated in four sheep over a period of 10 days using doubly labeled water (2H and 18O) and was compared with simultaneous respiration chamber measurements of CO2. The excess 2H and 18O measurements were corrected for the empirically determined effects of isotope rebreathing within the confines of the chambers. A weighted monoexponential curve was then fitted to the data from which isotope flux rates and ultimately rCO2 and water turnover (rH2O) estimates were made. The curve fits were weighted assuming a Poisson model. Selection of this weighting policy did not bias the results, and curvature in the data also appeared to have little effect on the rCO2 estimates. Fractionated evaporative water loss expressed as a fraction of rH2O (X) was estimated from water balance and breath water production estimates; the mean X was 0.145 and ranged from 0.108 to 0.183. Corrections for 2H loss in fecal solids reduced the mean rH2O (4,746 g/day) by 35.5 g/day and increased the mean rCO2 (332.3 l/day) by 21.2 l/day. Further corrections to account for 2H loss in methane (mean production rate 27.2 l/day) reduced rH2O by 33.8 g/day and increased rCO2 by 20.3 l/day. The final isotopic estimates of rH2O were 14.6 +/- 6.59% (n = 4) lower than direct measurements and the mean rCO2 was 3.5 +/- 14.48% (n = 4) lower than the chamber measured rCO2. However, in one of the animals studied the rCO2 deviated markedly from the chamber-derived value, and this discrepancy has yet to be explained. When this animal was excluded from the comparisons, the standard deviation was greatly reduced (+/- 3.6, n = 3) and the mean overall error on rCO2 was +3.6%.

Animals↗
PubMed1994

Economic deprivation and early childhood development.

We consider 3 questions regarding the effects of economic deprivation on child development. First, how are developmental outcomes in childhood affected by poverty and such poverty correlates as single parenthood, ethnicity, and maternal education? Second, what are the developmental consequences of the duration and timing of family economic deprivation? And, third, what is the comparative influence of economic deprivation at the family and neighborhood level? We investigate these issues with longitudinal data from the Infant Health and Development Program. We find that family income and poverty status are powerful correlates of the cognitive development and behavior of children, even after accounting for other differences--in particular family structure and maternal schooling--between low- and high-income families. While the duration of poverty matters, its timing in early childhood does not. Age-5 IQs are found to be higher in neighborhoods with greater concentrations of affluent neighbors, while the prevalence of low-income neighbors appears to increase the incidence of externalizing behavior problems.

Black or African American↗
PubMed1993

Magnetic resonance imaging to visualize the internal anatomy in the Baller-Gerold syndrome.

The Baller-Gerold syndrome is identified by radial aplasia with craniosynostosis. Only 12 cases have been reported previously in the literature; none of the reports describe surgical treatment for the radial aplasia. We report the case of a 10-month-old female infant with this syndrome, including severe bilateral radial clubhands. A radial anlage, which was tethering growth of the ulna, was suspected on physical examination and confirmed with magnetic resonance imaging. Resection of the anlage resulted in dramatic improvement in elbow extension, but additional follow-up will be necessary to determine the complete functional effect of the procedure.

Craniosynostoses↗
PubMed1991

United States public policy and the elderly: the disproportionate risk to the well-being of women.

"Cross-sectional comparisons show that poverty among the aged in the United States has dropped dramatically over the last two decades. We use longitudinal data to identify economic events associated with unfavorable economic outcomes and to trace the influence of these events on women and men at different ages. We find that while social insurance programs appear to prevent severe financial hardship from the most frequent work-related events, they are far less effective in cushioning the economic impact of widowhood and divorce, especially for women. We suggest a number of policy changes that would provide some measure of social insurance against adverse family-related events."

Adult↗
PubMed1991

Poverty dynamics in widowhood.

Data from a national sample of widows of all ages were used to examine links between poverty and widowhood. We found that widowhood drops living standards by 18 percent, on average, and pushes 10 percent of women whose incomes were above the poverty line prior to widowhood into poverty after it. Not surprisingly, economic status prior to widowhood is the strongest predictor of status during widowhood. Striking in the data is the instability of family income during widowhood, producing substantial numbers of exits from poverty.

Age Factors↗