The LWb blood group as a marker of prehistoric Baltic migrations and admixture.
(17/1974)
Archaeological findings and historical records indicate frequent migrations and exchange of genetic material between populations in the Baltic Sea area. However, there have so far been very few attempts to trace migrations in this area using genetic markers. We have studied the Baltic populations with respect to exceptional variations in the frequencies of the Landsteiner-Wiener (LW) blood group. The frequency of the uncommon LWb gene was high in the Balts, around 6% among Latvians and Lithuanians, very low among the other western Europeans (0-0.1%) and apparently absent in Asiatic and African populations. From the Baltic region of peak frequency there was a regular decline of LWb incidence (a descending cline) in the neighboring populations: 4.0% in the Estonians, 2.9% in the Finns, 2. 2% in the Vologda Russians, and 2.0% in the Poles. Thus the distribution of LWb suggests considerable and extensive Baltic admixture, especially in the north and northeast direction. In Southern Sweden with an LWb frequency of 0.3%, the Baltic influence appeared slight, while in the population of the Swedish island Gotland in the middle of the Baltic Sea there was a significantly increased LWb frequency of 1.0% compared with that of Western European countries. The distinction of codominantly inherited LW antigenic forms, LWa and LWb (previously Nea), is known to be due to a single base substitution. Based on our population data, it is plausible that the expansion of this point mutation occurred only once during human history. Furthermore, our data indicate that the expansion of the LWb mutation occurred in Balts and that LWb can be considered a 'Baltic tribal marker', its presence in other populations being an indicator of the degree of Baltic genetic influence. (+info)
Development of antibody isotype responses to Schistosoma mansoni in an immunologically naive immigrant population: influence of infection duration, infection intensity, and host age.
(18/1974)
We have identified the influence of host and parasite factors that give rise to characteristic antibody isotype profiles with age seen in human populations living in different areas of schistosomiasis endemicity. This is important in the immunobiology of this disease. It is also of interest in the context of human responses to chronic antigen stimulation, vaccines, allergens, and other pathogens. In populations exposed to endemic schistosomiasis, factors such as intensity and duration of infection are age dependent. They therefore confound the influence of host age on antiparasite responses. Here, we resolved these confounding factors by comparing the developing antibody responses of an immunologically naive immigrant population as they acquired the infection for the first time with those of chronically infected resident inhabitants of the same region of Schistosoma mansoni endemicity in Kenya. Recent arrival in the area strongly favored immunoglobulin G3 (IgG3) responses against the parasite. The antibody isotype responses associated with human susceptibility to reinfection after chemotherapy were elevated in those suffering high intensities of infection (IgG4 responses against worm and egg antigens) or were characteristic responses of young children irrespective of the intensity or duration of infection (IgG2 responses against egg antigen). IgE responses against the adult worm, a response associated with resistance to reinfection after chemotherapy, increased with the ages of infected individuals and were also favored in those currently suffering higher intensities of infection. (+info)
Folkecology and commons management in the Maya Lowlands.
(19/1974)
Three groups living off the same rainforest habitat manifest strikingly distinct behaviors, cognitions, and social relationships relative to the forest. Only the area's last native Maya reveal systematic awareness of ecological complexity involving animals, plants, and people and practices clearly favoring forest regeneration. Spanish-speaking immigrants prove closer to native Maya in thought, action, and social networking than do immigrant Maya. There is no overriding "local," "Indian," or "immigrant" relationship to the environment. Results indicate that exclusive concern with rational self-interest and institutional constraints do not sufficiently account for commons behavior and that cultural patterning of cognition and access to relevant information are significant predictors. Unlike traditional accounts of relations between culture, cognition, and behavior, the models offered are not synthetic interpretations of people's thoughts and behaviors but are emergent cultural patterns derived statistically from measurements of individual cognitions and behaviors. (+info)
Cervical cancer screening among Cambodian-American women.
(20/1974)
Southeast Asian women have higher invasive cervical cancer incidence rates and lower Pap testing frequencies than most other racial/ethnic groups in the United States. However, there is little information about the cervical cancer screening behavior of Cambodian-American women. Cambodian residents of Seattle were surveyed in person during late 1997 and early 1998. The PRECEDE model was used to guide the development of items that assessed predisposing, reinforcing, and enabling factors associated with cervical cancer screening participation. The estimated overall survey response was 72%. Four hundred thirteen women completed our questionnaire. Approximately one-quarter (24%) of the respondents had never had a Pap test, and over one-half (53%) had not been screened recently. The following variables were positively associated with a history of at least one Pap smear: younger age, greater number of years since immigration, belief about Pap testing for postmenopausal women, prenatal care in the United States, and physician recommendation. Women who believed in karma were less likely to have ever been screened for cervical cancer than those who did not. Six variables independently predicted recent screening: age; beliefs about regular checkups, cervical cancer screening for sexually inactive women, and the prolongation of life; having a female doctor; and a previous physician recommendation for Pap testing. The study findings indicate that culturally specific approaches might be effective in modifying the cervical cancer screening behavior of immigrant women. Programs targeting Cambodian-Americans are likely to be more effective if they are multifaceted and simultaneously address predisposing, reinforcing, and enabling factors. (+info)
Probability of identity by descent in metapopulations.
(21/1974)
Equilibrium probabilities of identity by descent (IBD), for pairs of genes within individuals, for genes between individuals within subpopulations, and for genes between subpopulations are calculated in metapopulation models with fixed or varying colony sizes. A continuous-time analog to the Moran model was used in either case. For fixed-colony size both propagule and migrant pool models were considered. The varying population size model is based on a birth-death-immigration (BDI) process, to which migration between colonies is added. Wright's F statistics are calculated and compared to previous results. Adding between-island migration to the BDI model can have an important effect on the equilibrium probabilities of IBD and on Wright's index. (+info)
Case studies in international medicine.
(22/1974)
Family physicians in the United States are increasingly called on to manage the complex clinical problems of newly arrived immigrants and refugees. Case studies and discussions are provided in this article to update physicians on the diagnosis and management of potentially unfamiliar ailments, including strongyloidiasis, hookworm infection, cysticercosis, clonorchiasis and tropical pancreatitis. Albendazole and ivermectin, two important drugs in the treatment of some worm infections, are now available in the United States. (+info)
Prevalence and determinants of prone sleeping position in infants: results from two cross-sectional studies on risk factors for SIDS in Germany.
(23/1974)
The authors investigated whether there was a decline in infants sleeping prone and other modifiable risk factors for sudden infant death syndrome (SIDS) in Germany, where, as in some other countries, no nationwide intervention campaign against the prone sleeping position had been initiated. Data were obtained from parents by mailed questionnaires in two cross-sectional studies in 1991 (n = 3,330) and 1995 (n = 3,124). Prevalence of prone sleeping decreased from 37.6% to 8.7% (p < 0.05) in the German population and from 44.1% to 32.0% (p < 0.05) in the Turkish immigrant population. Parents who laid their infants prone in 1995 were less likely to follow advice from physicians, public media, and other parents (relative risks < 0.5, p < 0.05) and were more likely to have a low educational level, to be <20 years old, to be single parents, to have two or more children, to be raised in West Germany, or to be of Turkish ethnicity. Although the information on prone sleeping being a risk factor for SIDS became known among the population, these data suggest that subgroup-specific public intervention campaigns may be needed to reduce the prevalence of prone sleeping even further in those countries where no nationwide campaign has been initiated. (+info)
Occupations at increased risk of hepatitis A: a 2-year nationwide historical prospective study.
(24/1974)
The recent licensing of active hepatitis A vaccines raises the question of vaccine candidates. Although various groups of workers are at theoretical occupational risk of hepatitis A infection, no comprehensive quantitative data exist to determine which occupational groups should receive active vaccination. Therefore, the aims of this study were to identify occupations at risk for hepatitis A infection and to determine their relative risk. In this nationwide historical prospective study, the relative risk of hepatitis A among different occupations in Israel was determined according to the incidence of hepatitis A in different occupations during 1993 and 1994 compared with the incidence of hepatitis A in two standard populations. After age, gender, ethnicity, and time of immigration to Israel were controlled for, certain occupations showed a significant increased risk of hepatitis A: yeshiva students (standardized incidence ratio (SIR) = 9.98, 99% confidence interval: 7.55, 13.18), day care center and kindergarten staff (SIR = 5.47, 99% confidence interval: 3.50, 8.57), food industry workers (SIR = 5.41, 99% confidence interval: 1.92, 15.25), teachers (SIR = 4.02, 99% confidence interval: 2.92, 5.48), physicians and dentists (SIR = 3.77, 99% confidence interval: 1.78, 8.14), and therapists and medical technicians (SIR = 3.75, 99% confidence interval: 1.75, 8.14). Sewage workers and nurses did not show any significantly increased risk. The results were validated by comparison with an additional standard population. This first nationwide study identified occupations at risk of hepatitis A infection. It emerged that the authors' approach can provide a yardstick for measuring samples in both large and small countries that have a socioeconomic background similar to that of Israel. (+info)