Heritability of life span in the Old Order Amish

Although a familial contribution to human longevity is recognized, the nature of this contribution is largely unknown. We have examined the familial contribution to life span in the Old Order Amish (OOA) population of Lancaster County, Pennsylvania. Analyses were conducted on 1,655 individuals, representing all those born prior to 1890 and appearing in the most widely available genealogy, surviving until at least age 30 years, and with known date of death. Mean age at death (+/-SD) in this population was 70.7 +/- 15.6 years, and this did not change appreciably over time. Parental and offspring ages at death were significantly correlated, as were ages of death among siblings. Offspring longevity was correlated with longevity of both parents, and in more or less additive fashion. For example, mean offspring age at death was 69.4 +/- 15.3 years in individuals for whom both parents died before the age of 75 years (n = 280) and increased to 73.5 +/- 16.0 years in individuals for whom neither parent died before the age of 75 years (n = 311). These differences were highly significant (P = 0.006). We estimated heritability of life span to be 25% +/- 5%, suggesting that the additive effects of genes account for one quarter of the total variability in life span in the OOA. We conclude that longevity is moderately heritable in the OOA, that the genetic effects are additive, and that genetic influences on longevity are likely to be expressed across a broad range of ages. Published 2001 Wiley-Liss, Inc.

International Genetic Epidemiology Society: commentary on Darkness in El Dorado by Patrick Tierney

The International Genetic Epidemiology Society (IGES) has examined the charges against James V. Neel and his colleagues contained in the recently published book by Patrick Tierney entitled Darkness in El Dorado: How Scientists and Journalists Devastated the Amazon (W.W. Norton, 2000). The book implicates Neel in causing or promoting an epidemic of measles among the Yanomamö Indians of Venezuela in 1968 leading to "hundreds if not thousands" of deaths by using a "dinosaur" vaccine (Edmonston B) as a deliberate "experiment" to test his "eugenic" theories. Tierney also attempts to link this research, funded by the Atomic Energy Commission (AEC), with a broader tapestry of human radiation experiments. To investigate these serious charges, the IGES undertook a thorough examination of most source documents referenced in Tierney's book, Neel's field logs, notes, first-hand reports, contemporary writings, film sound tracks, etc., and conducted interviews with many relevant persons. The IGES finds that these allegations are false. Neel was not a eugenicist and was in fact highly critical of both the scientific basis of eugenics and its coercive social policies. In this regard, Tierney has grossly misrepresented Neel's views on a wide range of social implications of modern civilization for the long-term health of the gene pool. Far from causing an epidemic of measles, Neel did his utmost to protect the Yanomamö from the ravages of the impending epidemic by a vaccination program using a vaccine that was widely used at the time and administered in an appropriate manner. There was nothing experimental about the vaccination program, which in fact severely hindered the primary scientific objectives of the expedition. Although the research was funded in large part by the AEC, there was no element of radiation research and the work had no connection with the ethical abuses that have been reported from AEC-sponsored radiation research, such as studies of heavy isotopes. Neel's seminal contributions to a broad range of topics in human genetics have been extensively chronicled elsewhere. His research on the Yanomamö in particular has provided unique insights into the evolutionary biology of our species, the role of sociocultural practices, such as kinship relationships and selective pressures in shaping the genetic diversity of primitive population isolates, as well as the general picture of health in such populations. The IGES decries the damage done to the reputation of one of its founders and its first President and the misperception this book may have caused about the conduct of research in genetic epidemiology. Ethical issues about scientific research in primitive populations deserve serious and wide discussion, but the IGES condemns the gross misrepresentation of the facts and demonization of the principal characters in this book.

Linked markers and age at diagnosis

This paper examines the relationship between age at diagnosis and markers linked to a disease trait using 100 replicates from Problem 2A in Genetic Analysis Workshop 10. After establishing the relationship between age and the quantitative trait used to define affection status, Q1, we evaluated the relationship between age at diagnosis and a marker which was linked with Q1. We found that the presence of an F allele at marker 15 on chromosome 5 was significantly associated with delayed age of diagnosis. When we evaluated 100 replicates, we found that the regression coefficients in the survival analyses were separated into two approximately normal distributions. The location of these distributions was solely reflective of the presence of affected individuals with the F allele in a particular replicate. In the replicates in one of the distributions, we found tremendous changes in the variance after employing survival models for dependent data. While we suggest that survival analysis of dependent data may be an important tool in investigating genotype specific alterations in age at event, the findings of this study indicate that the method used may be very sensitive to certain types of missing data.

Familial analysis of event related potentials

This report summarizes our analysis of the auditory and visual event related evoked potentials. These data were collected as a component of the Collaborative Study on the Genetics of Alcoholism and distributed as a part of the data available for the Genetic Analysis Workshop 11. For this analysis, we collapsed the data collected from eight leads using principal components methods. Using four collapsed variables derived from the principal components, we used regression analysis to adjust for environmental and demographic variables. We then fit the best fitting regression model and calculated the residuals. Using the residuals, we performed segregation analysis using S.A.G.E. Finally, we applied Markov chain Monte Carlo reverse jump methods to identify areas with potential quantitative trait loci. Our findings indicate that there may be an underlying genetic component to the potentials.

A genome-wide search for susceptibility genes linked to alcohol dependence

We performed two-point linkage analysis during a genome-wide search for susceptibility genes that predispose to alcohol dependence with the Collaborative Study on the Genetics on Alcoholism (COGA) data made available for the Genetic Analysis Workshop 11 (GAW11). For chromosomes 1 and 4 our findings supported results reported by Reich et al. [1998] based on the same data. We found similarity between our findings in regions on chromosomes 8 and 10 and reported results for schizophrenia linkage studies. Differences between our results with COGA data and those obtained by Reich et al. [1998] are due to our use of a lod score method versus their use of the affected relative pair (sib pair) method.

Assessing linkage of monoamine oxidase B in a genome-wide scan using a univariate variance components approach

We report results when one alcoholism related quantitative trait, monoamine oxidase B (MAOB), is analyzed by the variance components approach for linkage [Amos, 1994; Amos et al., 1996] using the Collaborative Study on the Genetics of Alcoholism data set provided for the Genetic Analysis Workshop 11. We used two different covariate models, one with age at interview, sex, ethnicity, and smoking status and the other with age at interview, sex, and ethnicity. The univariate analysis showed 24 markers on four different chromosomes (1, 4, 9, and 12) to have evidence for linkage with the quantitative trait (single-point and multipoint linkage). However, when outliers for MAOB were removed, the significant evidence for linkage disappeared.

Assessment of estimation procedures for risk and onset hazard with dependent data

Analysis of the role of candidate genes as risk factors for age-dependent hereditary conditions often ignores the importance of dependence among sibships or other family clusters for age of onset. We examined the performance of several methods of survival analysis with dependent data using Collaborative Study on the Genetics of Alcoholism families as submitted for GAW11. Additionally, an arbitrary truncation of cluster size was performed to explore the potential impact of heterogeneity of family size on the resulting inferences concerning the role of candidate genes. Our results showed substantial differences in attribution of risk to candidate genes according to whether the method utilized allowed for dependence in onset age and according to whether the sample was truncated or arbitrarily stratified. Further work needs to be done to clarify the importance of properly accounting for dependent data in age-dependent phenotypes and in integrating these methods into widely used genetic analysis computer programs.

Genome scans for genetic predisposition to alcoholism by use of transmission disequilibrium test analyses

We report the results of the analysis of three measures of alcoholism and six associated symptoms using transmission disequilibrium (TDT) analysis on data from the Collaborative Study on the Genetics of Alcoholism data set. Implementation of identity-by-state (IBS) routines for error checking revealed 10 reported full siblings that were rejected as a full sibling to all of their purported full siblings with p < 0.05. TDT analysis revealed two loci with significant transmission disequilibrium (p < 0.001) on chromosomes 1 and 7. Analysis by parental origin found alleles at three loci displaying significant disequilibrium in the transmission of the paternal alleles for at least three of the nine tested traits. These loci are on chromosomes 6, 9, and 13. Analyses of Caucasian families alone and the use of a single affected individual from each family also yielded significant results for the loci on chromosomes 6, 9, and 13.

The effect of inbreeding on early childhood mortality: twelve generations of an Amish settlement

An unresolved issue in research on child survival is the extent to which familial mortality risk in infancy is due to biological influences net of sociodemographic and economic factors. We examine the effect of consanguinity on early childhood mortality in an Old Order Amish settlement by using the inbreeding coefficient, an explicit measure of the degree of relatedness in one's ancestry. Inbreeding has a net positive effect on neonatal and postneonatal deaths. We find social, demographic, and population-based sociocultural explanations for this effect among the Amish population which is known to experience certain genetically transmitted defects associated with mortality.

Acceleration-deceleration injuries to the brain in blunt force trauma

Blunt force trauma to the stationary head is generally associated with cortical-subcortical injuries located at the site of impact (i.e., coup contusions). We present 2 cases of cerebral contusion injury secondary to falling tree limbs hitting the head, illustrating an exception to this observation. In each case, the most prominent lesions were white matter hemorrhagic contusions similar to those associated with acceleration-deceleration types of injuries characterizing falls or motor vehicle accidents (i.e., contrecoup contusions). The proposed pathogenesis for these observed lesions is a forceful impact resulting in the acceleration of the head and brain of a magnitude comparable with that in a motor vehicle accident or a fall.

Linkage analysis of chromosome 1q markers in 136 prostate cancer families. The Cancer Research Campaign/British Prostate Group U.K. Familial Prostate Cancer Study Collaborators

Prostate cancer shows evidence of familial aggregation, particularly at young ages at diagnosis, but the inherited basis of familial prostate cancer is poorly understood. Smith et al. recently found evidence of linkage to markers on 1q, at a locus designated "HPC1," in 91 families with multiple cases of early-onset prostate cancer. Using both parametric and nonparametric methods, we attempted to confirm this finding, in 60 affected related pairs and in 76 families with three or more cases of prostate cancer, but we found no significant evidence of linkage. The estimated proportion of linked families, under a standard autosomal dominant model, was 4%, with an upper 95% confidence limit of 31%. We conclude that the HPC1 locus is responsible for only a minority of familial prostate cancer cases and that it is likely to be most important in families with at least four cases of the disease.

A clinical trial to evaluate the effect of vitamin C supplementation on in vitro mutagen sensitivity. The University of Texas M. D. Anderson Clinical Community Oncology Program Network

Mutagen sensitivity, as measured by an in vitro assay, has been described as a risk factor for the development of several tobacco-related epithelial cancers. In vitro studies have indicated that sensitivity to the clastogenic effects of bleomycin on chromosomes was reduced with the introduction of ascorbic acid in a dose-dependent relationship. We report the results of a randomized clinical trial to determine whether increasing levels of oral ascorbic acid could reduce the levels of mutagen sensitivity. For this study, we recruited 228 healthy smokers from 21 centers around the country through the Clinical Community Oncology Program. Each individual was randomly assigned to one of four daily regimens: placebo, 1 g of ascorbic acid, 2 g of ascorbic acid, or 4 g of ascorbic acid. Treatments were administered for 16 weeks. Assessment of mutagen sensitivity was made at baseline and at weeks 4, 16, and 20 (4 weeks after cessation of treatment). Serum ascorbic acid levels were measured at baseline and at weeks 4 and 16. Demographic and risk factor data were collected at baseline and at each-measurement point. Analyses measured the differences of mutagen sensitivity levels across the four treatment arms, as well as investigating the correlation between serum ascorbic acid level and mutagen sensitivity levels in individuals. We did not find a dose-response relationship between ascorbic acid intake and mutagen sensitivity. Additionally, we did not find an association between serum ascorbic acid levels and mutagen sensitivity.

Morphological and electrophysiological properties of neurons in an area of the chick brain involved in learning

The intermediate, medial part of the hyperstriatum ventrale (IMHV) is an area of the avian forebrain which is essential for two forms of early learning in the domestic chick. We have developed an in vitro slice preparation which contains part of the IMHV and have found that the electrophysiological properties of the area show a considerable degree of plasticity. In particular, age and prior learning appear to modify the properties of single neurons recorded intracellularly. We have used the in vitro slice preparation to make intracellular recordings from 38 single neurons in the IMHV and have then dye-injected each cell to find out whether there is any relationship between electrophysiological and morphological characteristics. The basic membrane properties of each neuron were measured. Responses to standard electrical stimuli, delivered extracellularly, were also recorded, and each neuron was classified on this basis. Finally, the presence or absence of spontaneously occurring bursts of EPSPs was noted. At the end of recording biocytin was injected into the cell. After the tissue had been processed, each cell was drawn. The area of the cell body was measured, the number of dendrites was counted, and dendritic extent and branching were estimated. Each cell was also classified as 'spiny' or 'non-spiny'. We found that neurons displaying one particular type of response to external stimulation possessed a well defined set of morphological and electrical properties. In addition, three parameters--electrical resistance, somatic area, and the presence or absence of dendritic spines--were related to specific subsets of anatomical and physiological characteristics. The possible relevance of these findings to the plasticity of the IMHV is discussed.

Inheritance of susceptibility to bleomycin-induced pulmonary fibrosis in the mouse

Based on the range of patient responses to treatment, and on animal studies, it is hypothesized that individual variation in sensitivity to bleomycin-induced pulmonary fibrosis is controlled genetically. A genetic model has been developed by (a) establishing a distinct difference in bleomycin-induced lung damage in two inbred strains of mice [parental generation: C57BL/6J (fibrosis-prone phenotype) and C3Hf/Kam (fibrosis-resistant phenotype)] and (b) characterizing inheritance of the fibrosing phenotype in the F1 (first filial) and F2 (F1 intercross; second filial) generations derived from the parental strains. Male mice received 100 mg/kg and female mice 125 mg/kg of bleomycin via s.c. osmotic minipump. The animals were sacrificed 8 weeks after treatment or when their breathing rate indicated respiratory distress. The percentage of lung with fibrosis for each mouse was quantified with image analysis of a histological section of the left lung. The mean percentage of fibrosis for the C57BL/6J males was 8.4 +/- 0.8% (SE) and 4.4 +/- 0.8% for females, and the C3Hf/Kam mice of either sex did not present the fibrosing lesion (mean score, 0%). Significant difference (P = 6 x 10(-6)) was measured in percentage of fibrosis between the two strains of F1 males, but not F1 females (P = 0.38), suggesting the presence of an X-linked factor associated with the fibrosing phenotype. From an ANOVA the X-linked factor is estimated to contribute 19% of the fibrosis phenotype. A genetic model of two or three loci controlling the fibrosing phenotype is proposed from the data of the parental, F1, and F2 generations. The mouse model demonstrates that susceptibility to bleomycin-induced pulmonary fibrosis is a heritable trait controlled by a few genetic loci.

Effect of systemic steroids on ileal pouch-anal anastomosis in patients with ulcerative colitis

BACKGROUND

Long-term steroid therapy predisposes to postsurgical complications, especially in patients with inflammatory bowel disease.

PURPOSE

This study was undertaken to determine incidence of early septic complications after ileal pouch-anal anastomosis (IPAA) in patients who are undergoing prolonged steroid therapy.

METHODS

We reviewed charts of 692 patients undergoing restorative proctocolectomy and IPAA to treat ulcerative colitis. Incidence of early (within 30 days) septic complications and sepsis-related reoperations, in patients who were having high-dose (>20 mg of prednisone per day) and low-dose steroid therapy (<20 mg of prednisone per day) for more than one month before surgery, was compared with patients who were not receiving steroid therapy. Follow-up included an annual questionnaire and physical examination.

RESULTS

Patients without steroid dose data recorded were excluded (n = 21). Of the 671 remaining patients, 310 received no steroids, 169 received low-dose steroids, and 192 received high-dose steroids. These three groups were similar in gender composition, age at surgery, types of anastomosis (stapled or handsewn), and incidence of diabetes mellitus, peripheral vascular disease, and obesity. Early septic complications were found in 18 (6 percent), 14 (8 percent), and 12 (6 percent) patients without steroid therapy, those having low-dose steroid therapy, and those having high-dose steroid therapy (P = 0.57), respectively. Sepsis- related reoperation rate (P = 0.73) and number of sepsis-related pouch excisions (P = 0.79) did not differ between groups. In patients undergoing IPAA without ileostomy, early septic complications were found in one (3.8 percent), two (20 percent), and five (50 percent) patients without steroid treatment, low-dose steroid therapy, and high-dose steroid therapy (P = 0.004), respectively.

CONCLUSION

In patients who are undergoing IPAA with diversion for ulcerative colitis, prolonged systemic steroid therapy before surgery is not associated with increased septic complications.

Stapled ileal pouch anal anastomoses are safer than handsewn anastomoses in patients with ulcerative colitis

BACKGROUND

One of the theoretic advantages of using a stapled versus handsewn ileal pouch anal anastomosis (IPAA) in restorative proctocolectomy is a reduction in septic complications. We performed this study to compare the incidence of early septic complications in patients undergoing restorative proctocolectomy with stapled or handsewn IPAA.

PATIENTS AND METHODS

A chart review of 692 patients undergoing restorative proctocolectomy for treatment of ulcerative colitis was performed. The incidence of early septic complications in patients having stapled IPAA was compared to that in patients having handsewn IPAA. Follow-up studies included an annual questionnaire and physical examination.

RESULTS

Of the 692 patients, 238 had handsewn IPAA and 454 had stapled IPAA; these two groups were similar in sex, duration of disease, age at surgery, and type of surgical procedure performed. In the handsewn IPAA group, 25 patients (10.5%) had 32 septic complications, and 24 required 89 reparations. In 7 patients, the pouch was excised. In the stapled IPAA group, 21 patients (4.6%) had 23 septic complications, and 14 required 40 reparations. One patient needed pouch excision. There were more patients (P=0.0001) with early septic complications, and more (P<0.0001) pouch excisions because of these complications, in patients with handsewn IPAA than in patients with stapled IPAA. The sepsis-related reoperation rates did not differ significantly.

CONCLUSIONS

The stapled technique for IPAA has fewer septic complications and results in fewer sepsis-related pouch excisions, in our hands, than the handsewn technique technique, for treating patients with ulcerative colitis.

Electrophysiological correlates of prior training: an in vitro study of an area of the avian brain which is essential for early learning

Day-old domestic chicks will peck at any small, distinct object, such as a metal bead. One-trial passive avoidance learning can be established by coating the metal bead with methyl anthranilate (MeA) and allowing the birds to peck it once, after which they conspicuously avoid it. We have used birds successfully trained not to peck metal beads, and a control set of chicks where the training beads were innocuously dipped in water. Brain slices were prepared from both groups, containing the left, intermediate, medial part of the hyperstriatum ventrale (IMHV)--a region essential for this form of early learning. The electrophysiological properties of neurones in the IMHV were examined in vitro. Neurones recorded intracellularly in slices taken from MeA-trained birds had higher membrane resistances than did cells from water-trained controls. MeA training was also associated with an increased incidence of spontaneous, large EPSPs. Field responses to local electrical stimulation appeared to be somewhat greater in MeA-trained birds than in water-trained controls. In contrast, field potentials proved harder to potentiate with a burst of relatively high frequency stimulation in MeA-trained birds: the change in amplitude was less in MeA-trained birds, and there was less variability than in slices from water-trained controls.

Comparison of methods for survival analysis of dependent data

Analysis of dependent survival data by conventional partial likelihood methods produces unbiased estimates of the regression coefficients but incorrectly estimates their variance. Here we compared the conventional partial likelihood methods with two alternative methods for analyzing dependent survival data. The first alternative method estimated the regression coefficient by the partial likelihood approach but adjusted the variance to account for clustering. The second alternative method used marginal likelihoods to estimate both the regression coefficient and its variance. We evaluated the performance of the three methods using simulated and actual data. Simulated data were used to examine bias, efficiency, type I errors, and power. An Old Order Amish genealogy was analyzed under these models to illustrate their performance on real data. The simulation study showed that all three methods provided unbiased estimates of the regression coefficient, but the efficiency of the estimated regression coefficient varied according to the simulation conditions. The standard partial likelihood method showed increasing type I error as the dependence increased within clusters. Both alternative methods had acceptable levels of type I errors at all dependence levels. In the analysis of genealogic data, the regression coefficient was similar in the three methods showing stable estimates of the regression coefficients. The variance estimates from the alternative methods were slightly different from the conventional method, suggesting a flow level of dependence. This study displays the effect of violating the independence assumption and provides guidelines for using alternative statistical methods.

Age and the effects of 2-D,L-amino-5-phosphonovalerate in an area of the chick forebrain which is essential for early learning

The intermediate, medial part of the hyperstriatum ventrale (IMHV) is a region of the avian forebrain which is known to be essential for early learning in the domestic chick. The IMHV in an in vitro slice preparation displays two forms of synaptic plasticity. The incidence of both varies with age and is maximal between 3 and 5 days post-hatch. Since NMDA receptors are critical for at least one of these plasticities, we have investigated the relationship between age and the contribution of NMDA receptors to the field response evoked by local, low-frequency stimulation and have found that the magnitude of the NMDA-dependent component of the response varies with age peaking between 3 and 5 days post-hatch. Spontaneous neural activity, recorded intracellularly, can be completely and reversibly silenced by NMDA receptor blockade and the incidence of spontaneous activity also varies with age, peaking between 3 and 5 days. These results suggest that the IMHV contains NMDA receptors which can be activated near resting membrane potential. Either the efficiency or the numbers of these receptors is maximal at a specific point in development and their peak activity coincides with a peak in synaptic plasticity. These characteristics are similar to those reported for young mammals.

Genetic susceptibility to lung cancer as determined by lymphocytic chromosome analysis

Chromosomal anomalies were analyzed in the lymphocyte cultures among 96 untreated lung cancer patients and 74 clinically normal comparison subjects. The analysis revealed that >15% of the lung cancer patients showed structural or numerical rearrangements in chromosomes 1,3,5,7,9,12,14, and 21. A case control comparison showed that these aberrations were significantly higher in chromosome 7 [odds ratio (OR) = 2.32; 95% confidence interval (CI), 1.14 and 4.82], chromosome 9 (OR = 2.61; 95% CI, 1.27 and 5.48), chromosome 12 (OR = 4.10; 95% CI, 1.40 and 14.54), and chromosome 21 (OR = 7.75; 95% CI, 1.73 and 70.80) of the patients than in the controls. However, only chromosome 9 (OR = 3.57; 95% CI, 1.33 and 9.46) and chromosome 21 (OR = 6.94; 95% CI, 3.15 and 9.98) retained significance after stratifying on smoking status. Among the lung cancer patients, the breakpoints cluster in specific regions of some of these chromosomes. These regions are 1p13-q21, 3q21-q13, 7p12-q12, 7q12-q12,7q22, 7q32, 9p13-q13, 12p13, 14q11, and 14q32. The distribution of lung cancer patients, according to histological types, showed that aberrations in chromosomes 1,7, and 9 dominated the scenario of chromosomal changes in non-small cell lung carcinomas. Thus, the data on lymphocytic chromosomal rearrangements in lung cancer patients not only indicate the importance of specific genetic changes in the etiology of lung cancer but also emphasizes the putative role of such analysis in determining primary genetic abnormalities in the large heterogeneous group of lung cancers.