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F I Lewitter

Publications and source records attributed to F I Lewitter.

11 recordsLinked to original sources
PubMed1989

Genotypic and phenotypic similarities in pulmonary function among family members of adult monozygotic and dizygotic twins.

Population studies have demonstrated that obstructive airways disease aggregates within families. The authors used a twin family model of analysis to estimate the genetic and environmental influences on pulmonary function. A total of 1,635 members of 414 families of adult twins (252 monozygotic, 162 dizygotic) enrolled in the Greater Boston Twin Registry were studied between 1981 and 1982. Correlations in levels of forced expiratory volume in one second (FEV1) and forced vital capacity (FVC), adjusted for age, sex, height, and current smoking status, were compared among 16 groups of relatives sharing various degrees of genetic relatedness. A direct relation between shared genotype and the magnitude of the familial correlations for pulmonary function was observed. For FEV1, the correlations were 0.71 for monozygotic twins (100% shared genotype), 0.16 to 0.29 for relatives with 50% shared genotype, 0.09 to 0.27 for relatives with 25% shared genotype, 0.06 for cousins with 12.5% shared genotype, and -0.14 to 0.14 for unrelated family members. Correlations for FVC were similar. Stratification of the analysis by concordance or discordance for passive tobacco smoke exposure or for frequency with which families visited one another did not systematically alter these relations. These data suggest that phenotypic similarities in pulmonary function relate directly to genetic similarities, and are consistent with a multifactorial mode of inheritance.

Adolescent↗
PubMed1987

Genetic and environmental control of blood pressure in twins and their family members.

An interdisciplinary study, in adult twins and their family members, of the genetic and environmental determinants of complex physiologic functions is in progress. This report summarizes our initial studies of the control of the level of systolic (K1) and diastolic (K5) blood pressure in 202 monogygotic (MZ) and 121 dizygotic (DZ) twins, their spouses and their children. Correlation coefficients for blood pressure were adjusted for the covariates age, sex, body mass index (wt/ht2) and screener, all of which significantly augment most correlations. These adjusted correlation coefficients in MZ twins are 0.5 for both K1 and K5 blood pressure. For DZ twins, the adjusted correlation coefficients are 0.21 (K1) and 0.24 (K5). MZ twin-offspring adjusted correlation coefficients are higher than MZ twin-niece/nephew adjusted correlation coefficients (0.12 and 0.06, respectively, for K1; 0.20 and 0.13, respectively, for K5), despite the genetic identity of these relationships. That environmental factors may explain these differences is suggested by other differences in adjusted correlation coefficients that are greater than those predicted by the degree of genetic similarity. In addition, we have assessed the relationship between two biochemical-physiological processes, the urinary excretion of kallikrein and transport of sodium in the erythrocyte (the sodium countertransport and the sodium-potassium-chloride cotransport systems), and blood pressure control, since both have been implicated in the control of blood pressure level. Although we found evidence for substantial genetic control of both phenomena, we were unable to establish any correlation between either function and the level of blood pressure in our normotensive subjects. These data point to the operation of three broad categories of control of level of blood pressure: constitutional factors (age, sex, body mass), genetic factors and environmental factors. The identities of the genetic and environmental factors are unknown at this time.

Adolescent↗
PubMed1987

Assessment of genetic and nongenetic influences on pulmonary function. A twin study.

To better understand the extent to which familial similarities in pulmonary function (PF) are attributable to genetic rather than to shared environmental influences, we studied the twinship aggregation of PF in 256 monozygotic (MZ) and 158 dizygotic (DZ) adult twin members of the Greater Boston Twin Registry. Genetic influences on various spirometric measures were estimated with twinship intrapair correlations adjusted using a regression model to control for similarities in the anthropomorphic characteristics of twins, and for the effects of a number of environmental factors that included childhood respiratory illness, occupational dust exposure, and smoking history. A significant influence of smoking on all air-flow measures was observed in this population for whom genetic similarities were adjusted. However, highly significant adjusted intrapair correlations for all spirometric measures, ranging from 0.52 to 0.76, were observed for the MZ twins. The intrapair correlations for the DZ twins were approximately one-half the magnitude of those for the MZ twins. These data suggest that a large proportion of the measured variability in PF may be accounted for by genetic influences other than those associated with body size.

Adult↗
PubMed1986

The GenBank genetic sequence databank.

The GenBank Genetic Sequence Data Bank contains over 5700 entries for DNA and RNA sequences that have been reported since 1967. This paper briefly describes the contents of the database, the forms in which the database is distributed, and the services we offer to scientists who use the GenBank database.

Animals↗
PubMed1985

The GenBank nucleic acid sequence database.

The GenBank nucleic acid sequence database is a computer-based collection of all published DNA and RNA sequences; it contains over five million bases in close to six thousand sequence entries drawn from four thousand five hundred published articles. Each sequence is accompanied by relevant biological annotation. The database is available either on magnetic tape, on floppy diskettes, on-line or in hardcopy form. We discuss the structure of the database, the extent of the data and the implications of the database for research on nucleic acids.

Base Sequence↗
PubMed1984

Genetic and environmental determinants of level of pulmonary function.

Measurements of level of pulmonary function (one second forced expiratory volume (FEV1) and forced expiratory flow between the 25% and 75% volume points (FEF 25-75)) were obtained on members of 404 nuclear families living in East Boston, Massachusetts in 1974. These families were ascertained through a random sample of children aged 5-9 years. Measurements were obtained on family members on three separate occasions during a 5-year period. These data were subjected to the techniques of path analysis to study the relative contributions of heredity and environment to individual levels of pulmonary function. Genetic heritability was found to be consistent through time (41-47%) and was the same for parents and their children. Common familial environmental effects on level of pulmonary function explained 1-4% of the variability in children and 11-28% in adults. Furthermore, we were able to confirm prior epidemiologic analysis of these data which have demonstrated an effect of maternal smoking on the level of pulmonary function in their children.

Boston↗
PubMed1982

Familial aggregation of blood pressure in a highly inbred community, Abu Ghosh, Israel.

Abu Ghosh is a highly inbred community of more than 2000 Israeli Arabs in which all members are descendants of two brothers and in which individual blood pressures, rates of hypertension, and corresponding morbidity and mortality from cardiovascular disease are inordinately high. Accordingly, patterns of familial aggregation of blood pressure were investigated to determine if the population structure of this community might affect familial aggregation. In a study of children aged 2-14 years, significant familial aggregation of blood pressure was found in 797 children in 220 families. Intraclass correlation coefficients for systolic, Korotkoff IV and Korotkoff V diastolic blood pressures were 0.20, 0.21, and 0.26, respectively (all p less than 0.001). When correlated for Quetelet's index, the correlation coefficients were 0.21, 0.19, and 0.23, respectively (all p less than 0.001). Father-child correlation coefficients were 0.15, 0.18 and 0.12 with p-values of p = 0.003, p less than 0.001 and p = 0.024, respectively. Mother-child correlations were not significant. Adjustment for Quetelet's index increased the father-child correlations (p less than 0.001), but the mother-child correlations remained not significant. Although father-son correlations tended to be stronger than father-daughter correlations, and mother-daughter correlations tended to be stronger than mother-son correlations, these were trends and not statistically significant. Although the Abu Ghosh community is an extended family of common, known ancestry, the sib-sib aggregations were not different from those found in random families, but the father-child aggregations were unique and warrant further study.

Adolescent↗
PubMed1980

Genetic models of reading disability.

Test data collected on 133 reading-disabled (RD) children and their nuclear families who participated in the Colorado Family Reading Study were subjected to segregation analysis utilizing the technique of Elston and Yelverton (1975) for a continuous phenotypic measure. The possibility of genetic heterogeneity of RD was investigated by analyzing four subsets of data: all families, families with male probands, families with female probands, and families with severely affected probands. Furthermore, an analysis of the children's data was compared to that of all family members to investigate the possibility that the disorder may be manifested differently in adults. Results from the four subsets of data show that RD is etiologically heterogeneous. Compatibility with a major recessive gene for RD was demonstrated for families with female probands. Analyses of the children's data alone give results consistent with both environmental and genetic determination of RD.

Child↗
PubMed1978

Familial nature of reading disability.

An extensive psychometric test battery was administered to 125 children with a reading disability, to their parents and siblings, and to members of 125 matched control familes (N = 1,044). In addition to expected differences in spelling and reading, probands obtained significantly (P less than or equal to .01) lower scores than controls on tests of other cognitive abilities. Manifold deficits were also found in siblings and parents of probands, conclusively demonstrating the familial (genetic and/or common-family environmental) nature of the disorder.

Child↗