Search PubMed⌕ Search

Biomedical subjects

B H Cohen

Publications and source records attributed to B H Cohen.

At least 55 records · Page 3Linked to original sources
PubMed1990

Path analysis of familial resemblance of pulmonary function and cigarette smoking.

The techniques of path analysis were utilized to assess the relative importance of genetic factors, personal smoking behavior, and shared environment in the resemblance of pulmonary function among relatives using both cross-sectional and longitudinal data from nuclear families. Data on 1-s forced expiratory volume, FEV1 (adjusted for age, sex, race, height, and ascertainment group) and the number of cigarettes smoked per day were available on 978 individuals in 384 nuclear families residing in the Baltimore metropolitan area. All these individuals were seen twice between 1971 and 1981, with an average of 5 yr between visits. The direct effect of an individual's own smoking explained 10 and 3% of variation in adjusted FEV1 among parents and offspring, respectively. Shared environmental factors influencing personal smoking behavior accounted for 5% of the parent-offspring correlation in adjusted FEV1 and 3% of the sibling correlation in adjusted FEV1 in this sample. Undefined environmental factors that influenced an individual's smoking habits and could be shared among relatives were found to explain 19% of the familial correlations in smoking. Genetic heritability estimates ranged between 36 and 40%, with no evidence of intergenerational differences in the expression of apparent genetic control of pulmonary function.

Adult↗
PubMed1990

Patterns of cigarette smoking among Hispanics in the United States: results from HHANES 1982-84.

In the 1982-84 Hispanic Health and Nutrition Examination Survey, the prevalence of cigarette smoking was examined among Mexican Americans, Puerto Ricans, and Cuban Americans in the United States. Among 20-74 years olds, the age-adjusted smoking rates for Mexican American, Puerto Rican, and Cuban American men were high--42.5, 39.8, and 41.6 percent, respectively. Quite striking among Cuban American men was the high smoking rate among 20-34 year olds (50.1 percent), the highest smoking rate in the three Hispanic groups compared. The age-adjusted smoking rates for Mexican American, Puerto Rican, and Cuban American women were much lower than those for men-23.8, 30.3, and 24.4 percent, respectively. Both Puerto Rican and Cuban American men were more likely to be heavy smokers (52.3 and 64.1 percent, respectively, smoking a pack or more a day) as compared to the Mexican Americans (33.8 percent smoking a pack or more a day). The pattern was the same for women, with Mexican American women being lighter smokers (18.8 percent smoking a pack or more a day) as compared to heavy smoking among Puerto Rican and Cuban American women (35.1 and 48.6 percent, respectively, smoking a pack or more a day). Given the health hazards of smoking, future research and intervention are required for those groups with high exposure to cigarette smoking.

Adult↗
PubMed1990

Localized 31P magnetic resonance spectroscopy of large pediatric brain tumors.

Fourteen children aged 1 week to 16 years, with a variety of large or superficial brain tumors, underwent localized in vivo 31P magnetic resonance spectroscopy of their tumor. Quantitative spectral analysis was performed by measuring the area under individual peaks using a computer algorithm. In eight patients with histologically benign tumors the spectra were considered to be qualitatively indistinguishable from normal brain. The phosphocreatine/inorganic phosphate ratio (PCr/Pi) averaged 2.0. Five patients had histologically malignant tumors; qualitatively, four of these were considered to have abnormal spectra, showing a decrease in the PCr peak. The PCr/Pi ratio for this group averaged 0.85, which was significantly lower than that seen in the benign tumor group (p less than 0.05). No difference between the two groups was seen in adenosine triphosphate or phosphomonoesters. It is concluded that a specific metabolic "fingerprint" for childhood brain tumors may not exist, but that some malignant tumors show a pattern suggestive of ischemia.

Adenosine Triphosphate↗
PubMed1989

Vitamin A, cigarette smoking, and airway obstruction.

The hypothesis that vitamin A, or foods rich in vitamin A such as milk, protects against the development of airway obstruction was tested in a subsample of data from the 1971-1975 National Health and Nutrition Examination Survey. The relative risk (estimated by relative odds) of having airway obstruction, defined as a FEV1/FVC less than or equal to 65%, was measured for different levels of nutrient and food group intakes after adjustment for age, sex, Quetelet Index, caloric intake, and cigarette smoking. Among the white respondents (never smokers or current smokers) whose recalled diet could be considered as typical of their usual diet, the relative odds of having airway obstruction was inversely related to vitamin A intake (x2 for trend = 7.2, p less than 0.01). In the analysis by food groups, the adjusted relative odds of airway obstruction for meat and poultry were 2.4 (95% confidence limits: 1.0 to 5.8) and for milk 1.6 (95% confidence limits: 1.0 to 2.5). The association of airway obstruction with lack of vitamin A or milk intake was clearer among smokers. These findings suggest that a diet poor in vitamin A increases the risk of airway obstruction, and are consistent with the previously reported association of chronic bronchitis, milk intake, and smoking.

Adult↗
PubMed1989

Gadolinium-DTPA-enhanced magnetic resonance imaging in childhood brain tumors.

Gadolinium DTPA (Gd-DTPA) is a paramagnetic blood-brain barrier contrast agent for MRI that has been used primarily in adults. During May through October 1987, 17 children between the ages of 3 and 18 years with brain tumors underwent MRI examinations, before and after Gd-DTPA (11 gliomas, 4 medulloblastomas, 1 craniopharyngioma, and 1 child with neurofibromatosis and no pathologic diagnosis). We compared T1 and T2 Gd-DTPA-enhanced MRI with concurrent unenhanced MRI and enhanced CT, and then correlated this with the clinical and pathologic findings. Gd-DTPA enhanced tumors in all 7 patients with newly diagnosed tumors and enhanced tumors in 7 of 10 patients without clinical evidence of progressive disease at the time of the study. In the 7 new patients, Gd-DTPA defined tumor margins in all, and demonstrated internal tumor architecture (vessels, necrosis, and cysts) in 5. Areas believed to represent surgical scars showed varying degrees of enhancement. Leptomeningeal tumor spread, including spinal, not seen on pre-Gd-DTPA MRI or on contrast CT, was evident in 2 patients. Gd-DTPA enhancement obscured hemorrhage within the tumor (methemoglobin) in 2 patients. There were no significant side effects. These results suggest that Gd-DTPA-enhanced MRI (1) is safe in children, (2) demonstrates the extent and character of tumors better than unenhanced MRI and enhanced CT, and (3) may allow for noninvasive imaging of leptomeningeal disease, including the spine, not previously demonstrated by any other noninvasive neuroimaging technique.

Adolescent↗
PubMed1989

Incidence, types, and management of cancer in patients with neurofibromatosis.

Neurofibromatosis Type 1 (NF1) is a common genetic disease with an incidence of 1 in 3,000 to 4,000. Clinical manifestations may include cafe-au-lait macules, axillary freckling, neurofibromas, Lisch nodules, skeletal dysplasias, learning disabilities, and a variety of neoplasms. In persons with NF1, some malignancies occur at an increased incidence compared to the general population. These include central nervous system astrocytomas, especially involving the visual pathways; ependymomas; meningiomas; neurofibrosarcomas; rhabdomyosarcomas; nonlymphocytic leukemias; and pheochromocytomas. The authors discuss the dysplastic and malignant features associated with NF and the concept of NF as a "neurocristopathy."

Adult↗
PubMed1989

Cancer in relatives of leukemic patients with chromosomal rearrangements at rare (heritable) fragile-site locations in their malignant cells.

The cancer occurrence in relatives (N = 407) of 40 case probands (who had leukemia and rearrangements at the same chromosomal location as at least one of 23 recognized rare [heritable] autosomal fragile sites [Sutherland and Mattei 1987]) was compared both to cancer occurrence in relatives (N = 390) of 40 control probands (who had leukemia or other hematologic illness but no recognized chromosomal rearrangements) and to cancer incidence in the general population of the United States. Fragile-site carrier status was not determined in case or control probands. No significant excess of cancer in case relatives, compared with either control relatives or to general (SEER) population expectancies, was found. Furthermore, there was neither evidence of cancer at younger ages, when cases were compared with control relatives, nor an excess of cancer at multiple sites. Male relatives of cases did, however, show a small excess of cancer, especially in older age groups. There was a slight, but not statistically significant, excess of lung cancer in case relatives, with this deviation occurring almost exclusively in relatives of probands having rearrangements at 11q23 and having lymphoid leukemia. It is possible that heritable tendency to chromosomal rearrangement--and thus to cancer--is expressed in such a small proportion of family members that cancer excess in these families could not be detected with the numbers of relatives analyzed in this study, although there was no significant evidence for a hereditary predisposition to cancer in the families of probands with leukemia and with chromosomal rearrangements at the same apparent chromosomal location as rare fragile sites.

Adolescent↗
PubMed1988

Perceiver bias in the processing of human faces: neuropsychological mechanisms.

Previous research has suggested that in face-to-face contexts perceivers are biased to judge the side of the poser's face to their left as more similar to the full face than the side to their right. Traditional explanations of the perceiver bias have presumed that it is a visual field effect, with the side of the poser's face falling within the perceiver's left visual field dominating impressions of the full face. In this study, five experiments are reported. In the first experiment, the validity of the perceiver bias phenomenon was supported. The remaining experiments examined three alternative accounts of the neuropsychological processes that underlie the perceiver bias. No support was obtained for the visual field explanation, nor for an account of the bias as due to asymmetry in gaze patterns. Support was obtained for an account emphasizing a hemispatial bias in central processing. Despite equivalent intake of information from both sides of space, the brain may differentially weight information as a function of hemispatial origin. Practical and theoretical implications are discussed.

Adult↗
PubMed1988

Microcystic adnexal carcinoma: a case showing eccrine duct differentiation.

Microcystic adnexal carcinoma (MAC) is a cutaneous neoplasm comprised of pilar and sweat duct structures. Characteristically, the ductal structures manifest immunoreactivity for carcinoembryonic antigen (CEA) on immunostaining. The case of MAC discussed here shows strictly sweat duct differentiation. Using a monoclonal antibody to salivary mucin (CF-1) that is specific for eccrine duct, we identify the neoplastic structures to be of eccrine sweat duct histogenesis.

Aged↗
PubMed1988

Intracranial visual pathway gliomas in children with neurofibromatosis.

The association between neurofibromatosis and visual pathway gliomas is well documented. The introduction of computed tomography and magnetic resonance imaging has heralded a new era in the understanding of visual pathway gliomas. Both of these noninvasive neuroinvestigative techniques have demonstrated extensive abnormalities throughout the visual pathway in children with visual pathway gliomas, especially in those with neurofibromatosis. The clinical significance of these abnormal areas of brain, especially in asymptomatic patients, is unknown. In an attempt to clarify the incidence, natural history, and clinical course of patients with neurofibromatosis and visual pathway lesions, we reviewed our experience with 24 patients managed consecutively at Children's Hospital of Philadelphia over the past 12 years. The patients in this series were compared to 29 children with visual pathway gliomas without neurofibromatosis who were evaluated at our institution over the same period of time. Visual pathway gliomas in children with neurofibromatosis differ from those in children without neurofibromatosis. In general, lesions tended to be more extensive in patients with neurofibromatosis and the clinical course of these patients is more variable. Twelve of the 24 patients with neurofibromatosis in our series had symptoms of progressive disease at the time of diagnosis and underwent treatment with variable results. Twelve children with neurofibromatosis and visual pathway lesions had static lesions at the time of diagnosis and, to date, 3 have developed progressive disease. From our review we can make some recommendations concerning the management of children with neurofibromatosis and visual pathway gliomas, but many questions remain unanswered. Sequential follow-up of a large cohort of both asymptomatic and symptomatic children with neurofibromatosis and visual pathway lesions is needed to more definitively outline the best management approach for these patients.

Adolescent↗
PubMed1987

Robust inference for variance components models in families ascertained through probands: II. Analysis of spirometric measures.

Three spirometric measures of pulmonary function were used to estimate genetic and nongenetic components of variance for 781 members of 158 families ascertained through a proband with obstructive pulmonary disease. Forced expiratory volume in 1 sec (FEV1), forced vital capacity (FVC), and the ratio of these two (FEV1/FVC) were adjusted for age, sex, race, smoking, and height and used in a robust approach to estimate variance components after conditioning on the proband's observed value. The best fitting model for both residual FEV1/FVC and FEV1 included an additive genetic component representing 25% and 9% of the variation in these two traits, respectively. In addition, there was a significant correlation between parents in residual FEV1/FVC, and a component shared among full sibs was statistically significant for residual FEV1. No evidence of a genetic component for residual FVC was found in this analysis. Although these results agree with previous reports based on other populations in showing a substantial degree of direct genetic control over spirometric measures of pulmonary function, they also raise the possibility of etiologic heterogeneity.

Analysis of Variance↗
PubMed1987

Genetic heterogeneity of prematurity and intrauterine growth retardation: clues from the Old Order Amish.

We studied differences in the role of genetic factors in prematurity and intrauterine growth retardation with the use of data on 312 Amish singleton live children ascertained from Amish records in Lancaster county, Pennsylvania, between 1969 and 1980. Birth and death certificates were obtained on all children, and inbreeding coefficients of child, mother, and father were computed by use of the path method of tracing common ancestors in a unique genealogic registry of Amish ancestors dating back to the 1700s. Multivariate analysis with linear and log linear models showed that a lower mean gestational age and a higher risk of prematurity (less than 37 weeks) and borderline maturity (37 to 38 weeks) were significantly associated with increased maternal inbreeding but not child or paternal inbreeding. On the other hand, a higher risk of intrauterine growth retardation (less than the tenth percentile in birth weight for gestational age) and mild intrauterine growth delay (tenth to twenty-fifth percentile) were associated with increased child inbreeding but not maternal or paternal inbreeding. The analysis suggests the presence of genetic heterogeneity in the etiology of prematurity and intrauterine growth retardation; while prematurity is mostly related to the maternal genotype, intrauterine growth retardation is related to the fetal genotype. The study reemphasizes the need for separating low birth weight into prematurity and intrauterine growth retardation in genetic and epidemiologic studies.

Consanguinity↗
PubMed1987

An epidemiologic approach to the evaluation of the effect of inbreeding on prereproductive mortality.

Although many studies report deleterious effects of inbreeding on prereproductive mortality (death before age 20 years), such effects are usually measured in terms of genetic load, a concept much debated in the literature. To evaluate the public health impact of inbreeding on prereproductive mortality in terms of relative and attributable risks, the authors reviewed 31 studies with 294 observations comparing various stages of infant and child mortality in offspring of unrelated parents with offspring of first cousin, first cousin once removed, and second cousin marriages, respectively. Compared with offspring of unrelated parents, offspring of first cousin marriages have a higher risk of prereproductive mortality (median relative risk (RR) = 1.41, signed-rank test, p less than 0.01). Offspring of first cousin once removed and second cousin marriages had median relative risks of 1.16 and 1.26, respectively. Countries with relatively higher rates of consanguineous marriages (greater than 5%) had lower median relative risks than did countries with lower consanguinity rates. Also, the higher the mortality rate in the population, the lower the effect of consanguinity (median relative risk). Because of the rarity (less than 5%) and declining trends of consanguineous marriages in many places of the world, and because of their modest effect on prereproductive mortality (RR less than 2.0), it can be shown that the attributable risk of prereproductive mortality due to consanguineous marriages is less than 5%. Except for a few places with very high inbreeding levels, inbreeding has a minor impact on mortality in the prereproductive period.

Consanguinity↗
PubMed1987

Inbreeding and prereproductive mortality in the Old Order Amish. I. Genealogic epidemiology of inbreeding.

Epidemiologic patterns of inbreeding in the Old Order Amish were investigated using a unique genealogic registry of Lancaster County, Pennsylvania, Amish that contains information on 8,163 marriages, dating back to the time of the pioneer migrants in the 1700s and spanning more than 10 generations. The kinship coefficient for each marriage was computed using the path method of tracing common ancestors in the multigenerational pedigrees. Because of extensive genealogic connections, mean kinship coefficients and the proportion of related marriages have increased significantly over time, from 0.004 and 37%, respectively, for marriages before 1850 to 0.012 and 98%, respectively, for marriages after 1950. Demographic factors related to higher kinship levels include young age at marriage, large sibship size for both husband and wife, husband being a farmer, and marriages occurring in the marriage season (November or December). The rise in inbreeding levels in the Amish over time can be uniquely contrasted with the decline in inbreeding in most areas of the world. Furthermore, because some of the demographic factors related to high inbreeding levels may be associated with levels of mortality, such factors have to be taken into account when studying the effects of inbreeding on mortality in the Amish. This study uses an epidemiologic approach to the evaluation of inbreeding patterns in a population over time.

Consanguinity↗
PubMed1987

Inbreeding and prereproductive mortality in the Old Order Amish. II. Genealogic epidemiology of prereproductive mortality.

The effects of offspring and parental inbreeding on prereproductive mortality (death before age 20 years) in the historical population of the Lancaster County, Pennsylvania, Old Order Amish were investigated using the Amish genealogic registry, which contains information on 42,465 births dating to the time of the pioneer migrants in the 1700s. Inbreeding coefficients for offspring and parents were computed using the path method of tracing common ancestors in the multigenerational pedigrees. In this population, prereproductive mortality declined from about 15% in the late 1800s to about 5% after 1930. Offspring inbreeding was found to be an independent predictor of prereproductive mortality after multivariate adjustment for demographic risk factors for mortality. Moreover, the higher the coefficient, the higher the relative risk of prereproductive death, and the higher the risk of multiple deaths in the same sibship. There was no evidence of declining inbreeding effects over 10 generations of continuous inbreeding, nor of any significant parental inbreeding effects. Because of the high levels of inbreeding, it could be shown that inbreeding accounts for about 40% of all prereproductive deaths in the present population. Genetic load analysis showed an average of about 1.7 lethal equivalents and a mostly mutational load.

Adult↗