Linkage and linkage disequilibrium in chromosome band 1p36 in American Chaldeans with inflammatory bowel disease.
(9/548)
The idiopathic inflammatory bowel diseases (IBDs), consisting of Crohn's disease and ulcerative colitis, are complex genetic disorders involving chronic inflammation of the intestines. Multiple genetic loci have been implicated through genome-wide searches, but refinement of localization sufficient to undertake positional cloning efforts has been problematic. This difficulty can be obviated through identification of ancestrally shared regions in genetic isolates, such as the Chaldean population, a Roman Catholic group from Iraq. We analyzed four multiply affected American Chaldean families with inflammatory bowel disease not known to be related. We observed evidence for linkage and linkage disequilibrium in precisely the same region of chromosome band 1p36 reported previously in an outbred population. Maximal evidence for linkage was observed near D1S1597 by multipoint analysis (MLOD = 3.01, P = 6.1 x 10(-5)). A shared haplotype (D1S507 to D1S1628) was observed over 27 cM between two families. There was homozygous sharing of a 5 cM portion of that haplotype in one family and over a <1 cM region in the second family. Homozygous sharing of this haplotype near D1S2697 and D1S3669 was observed in one individual in a third multiply affected family, with heterozygous sharing in a fourth family. Linkage in outbred families as well as in this genetic isolate indicates that a pathophysiologically crucial IBD susceptibility gene is located in 1p36. These findings provide a unique opportunity to refine the localization and identify a major susceptibility gene for a complex genetic disorder. (+info)
Prevalence and trends of overweight among preschool children in developing countries.
(10/548)
BACKGROUND: Obesity during childhood is a matter of growing concern. Several reports show increasing rates of obesity in developed countries, whereas the extent of the problem in developing countries remains unknown. OBJECTIVE: The aim of this study was to fill this gap by quantifying the prevalence and trends of overweight among preschool children in developing countries. DESIGN: One hundred sixty nationally representative cross-sectional surveys from 94 countries were analyzed in a standardized way to allow comparisons across countries and over time. Overweight was defined as a weight-for-height >2 SDs from the National Center for Health Statistics/World Health Organization international reference median. Prevalences of wasted children (< -2 SDs) are also presented to enable comparisons between both ends of the distribution. RESULTS: The global prevalence of overweight was 3.3%. Some countries and regions, however, had considerably higher rates, and overweight was shown to increase in 16 of 38 countries with trend data. Countries with the highest prevalences of overweight are located mainly in the Middle East, North Africa, and Latin America. Rates of wasting were generally higher than those of overweight; Africa and Asia had wasting rates 2.5-3.5 times higher than overweight rates. Countries with high wasting rates tended to have low overweight rates and vice versa. CONCLUSIONS: These estimates show that attention should be paid to monitoring levels and trends of overweight in children. This, however, should not be done at the expense of decreasing international commitments to alleviating undernutrition. The data presented confirm that undernutrition remains a major public health problem worldwide. (+info)
Occupational risk factors for ill health in Gulf veterans of the United Kingdom.
(11/548)
OBJECTIVES: To study the association between occupational factors specific to the Armed Forces (rank, functional roles, Service, regular or reservist status and deployment factors) and symptomatic health problems in Gulf veterans, after sociodemographic and lifestyle factors have been accounted for. DESIGN: A postal cross sectional survey of randomly selected UK Gulf veterans was conducted six to seven years after the Gulf conflict. Physical ill health was measured using the Fatigue Questionnaire and a measure of the Centers for Disease Control and Prevention (CDC) multi-symptom syndrome. Psychological ill health was measured using the General Health Questionnaire and a post-traumatic stress measure. SETTING: Population of servicemen who were serving in the UK Armed Forces during the Gulf conflict between 1 September 1990 and 30 June 1991. PARTICIPANTS: 3297 Gulf veterans. MAIN RESULTS: In multivariate logistic regression, there was an inverse relation between higher rank and psychological and physical ill health (test of trend: General Health Questionnaire, p=0.004; post-traumatic stress, p=0.002; fatigue, p=0.015; CDC case, p=0.002). Having left the Armed Forces was associated with a two to three times increase in reporting ill health. Of the deployment factors, there was a weak association between being deployed as an individual reinforcement in a combat role and post-traumatic stress but there was no association between receiving pre-deployment training or post-deployment leave and ill health. Marital status and smoking were associated with psychological and physical ill health. CONCLUSIONS: Rank was the main occupational factor associated with both psychological and physical ill health in Gulf veterans. This may parallel the associations between socioeconomic status and morbidity in civilian populations. Ill health seems to be greater in those who return to civilian life. Sociodemographic factors also seem to be important in ill health in Gulf veterans. (+info)
Tracing European founder lineages in the Near Eastern mtDNA pool.
(12/548)
Founder analysis is a method for analysis of nonrecombining DNA sequence data, with the aim of identification and dating of migrations into new territory. The method picks out founder sequence types in potential source populations and dates lineage clusters deriving from them in the settlement zone of interest. Here, using mtDNA, we apply the approach to the colonization of Europe, to estimate the proportion of modern lineages whose ancestors arrived during each major phase of settlement. To estimate the Palaeolithic and Neolithic contributions to European mtDNA diversity more accurately than was previously achievable, we have now extended the Near Eastern, European, and northern-Caucasus databases to 1,234, 2, 804, and 208 samples, respectively. Both back-migration into the source population and recurrent mutation in the source and derived populations represent major obstacles to this approach. We have developed phylogenetic criteria to take account of both these factors, and we suggest a way to account for multiple dispersals of common sequence types. We conclude that (i) there has been substantial back-migration into the Near East, (ii) the majority of extant mtDNA lineages entered Europe in several waves during the Upper Palaeolithic, (iii) there was a founder effect or bottleneck associated with the Last Glacial Maximum, 20,000 years ago, from which derives the largest fraction of surviving lineages, and (iv) the immigrant Neolithic component is likely to comprise less than one-quarter of the mtDNA pool of modern Europeans. (+info)
Self-reported postwar injuries among Gulf War veterans.
(13/548)
OBJECTIVE: From September 1995 to May 1996, the authors conducted a telephone survey of Iowa military personnel who had served in the regular military or activated National Guard or Reserve during the Gulf War period. To assess the association between military service in a combat zone and subsequent traumatic injury requiring medical consultation, the authors analyzed veterans' interview responses. METHODS: Using data from the larger survey, the authors compared rates of self-reported postwar injuries requiring medical consultation in a sample of Iowa Gulf War veterans to the rates in a sample of Iowa military personnel who served at the same time, but not in the Persian Gulf. RESULTS: Of 3695 veterans, 605 (16%) reported a traumatic injury in the previous three months requiring medical consultation. Self-reported injuries were associated with service in the Persian Gulf (odds ratio 1.26; 95% confidence interval 1.02, 1.55). CONCLUSION: This finding is consistent with the results of earlier studies of traumatic injury mortality rates among war veterans. (+info)
The genetic legacy of Paleolithic Homo sapiens sapiens in extant Europeans: a Y chromosome perspective.
(14/548)
A genetic perspective of human history in Europe was derived from 22 binary markers of the nonrecombining Y chromosome (NRY). Ten lineages account for >95% of the 1007 European Y chromosomes studied. Geographic distribution and age estimates of alleles are compatible with two Paleolithic and one Neolithic migratory episode that have contributed to the modern European gene pool. A significant correlation between the NRY haplotype data and principal components based on 95 protein markers was observed, indicating the effectiveness of NRY binary polymorphisms in the characterization of human population composition and history. (+info)
Foot-and-mouth disease type O viruses exhibit genetically and geographically distinct evolutionary lineages (topotypes).
(15/548)
Serotype O is the most prevalent of the seven serotypes of foot-and-mouth disease (FMD) virus and occurs in many parts of the world. The UPGMA method was used to construct a phylogenetic tree based on nucleotide sequences at the 3' end of the VP1 gene from 105 FMD type O viruses obtained from samples submitted to the OIE/FAO World Reference Laboratory for FMD. This analysis identified eight major genotypes when a value of 15% nucleotide difference was used as a cut-off. The validity of these groupings was tested on the complete VP1 gene sequences of 23 of these viruses by bootstrap resampling and construction of a neighbour-joining tree. These eight genetic lineages fell within geographical boundaries and we have used the term topotype to describe them. Using a large sequence database, the distribution of viruses belonging to each of the eight topotypes has been determined. These phylogenetically based epidemiological studies have also been used to identify viruses that have transgressed their normal ecological niches. Despite the high rate of mutation during replication of the FMD virus genome, the topotypes appear to represent evolutionary cul-de-sacs. (+info)
Nuclear background determines biochemical phenotype in the deafness-associated mitochondrial 12S rRNA mutation.
(16/548)
The pathogenetic mechanism of the human mitochondrial 12S rRNA gene mutation at position 1555, associated with non-syndromic deafness and aminoglycoside-induced deafness, has been investigated in 33 transformants obtained by transferring mitochondria from lymphoblastoid cell lines into human mitochondrial DNA (mtDNA)-less (rho *206) cells. In this nearly constant nuclear background, 15 transformants derived from five symptomatic individuals from a large Arab-Israeli family, carrying this mutation in homoplasmic form, exhibited significant decreases compared with nine control transformants in the rate of growth in a medium containing galactose instead of glucose, as well as in the rates of mitochondrial protein synthesis and of substrate-dependent respiration. Most significantly, these decreases were very similar to those observed in nine transformants derived from three asymptomatic members of the family. This result in transmitochondrial cybrids is in contrast to the differences in the same parameters previously demonstrated between the original lymphoblastoid cell lines derived from the symptomatic and asymptomatic members of the Arab-Israeli family. In addition, the intragroup variability in biochemical dysfunction among the lymphoblastoid cell lines from different symptomatic or asymptomatic or control individuals was significantly reduced in the derived mitochondrial transformants carrying the same nuclear background. These observations provide strong genetic and biochemical evidence in support of the idea that the nuclear background plays a determinant role in the phenotypic manifestation of the non-syndromic deafness associated with the A1555G mutation. (+info)