Microcirculation in the labyrinth

Erythrocyte glucose-6-phosphate dehydrogenase (G-6-PD) activity and electrophoresis were investigated among 154 Indians living in a region hyperendemic for malaria at Alto Xingu, Mato Grosso, Brazil. No enzyme-deficient individual was found, and all subjects belonged to enzyme type B. No statistical difference in G-6-PD levels was found between tribes and sexes. The average of G-6-PD activity of the Indians was significantly higher than the normal mean values found by the same technique in Caucasians, Negroes and Japanese of S?o Paulo, Brazil. The high rates of G-6-PD activity of the Indians are not correlated to an increased reticulocytosis by hypochromic anaemia and appear to be typical of Indian or Indian-mixed populations. Resistance to malaria in those populations should not involve erythrocyte G-6-PD deficiency. It is suggested that the apparent association between G-6-PD deficiency and resistance to malaria found in other populations could be a statistical accident determined by the racial correlation between the incidence of G-6-PD deficiency and sickle-cell or thalassaemic haemoglobins among Negro and Mediterranean populations.     

Genetic variants of human T-lymphotrophic virus type II in American Indian groups

The human T-lymphotropic virus type II (HTLV-II) is found in many New World Indian groups in North and South America and may have entered the New World from Asia with the earliest migration of ancestral Amerindians over 15,000 years ago. To characterize the phylogenetic relationships of HTLV-II strains infecting geographically diverse Indian populations, we used polymerase chain reaction to amplify HTLV-II sequences from lymphocytes of seropositive Amerindians from Brazil (Kraho, Kayapo, and Kaxuyana), Panama (Guaymi), and the United States (the Navajo and Pueblo tribes of the southwestern states and the Seminoles of Florida). Sequence analysis of a 780-base pair fragment (located between the env gene and the second exons of tax/rex) revealed that Amerindian viruses clustered in the same two genetic subtypes (IIa and IIb) previously identified for viruses from intravenous drug users. Most infected North and Central American Indians had subtype IIb, while HTLV-II infected members of three remote Amazonian tribes clustered as a distinct group within subtype IIa. These findings suggest that the ancestral Amerindians migrating to the New World brought at least two genetic subtypes, IIa and IIb. Because HTLV-II strains from Amazonian Indians form a distinct group within subtype HTLV-IIa, these Brazilian tribes are unlikely to be the source of IIa viruses in North American drug users. Finally, the near identity of viral sequences from geographically diverse populations indicate that HTLV-II is a very ancient virus of man.     

Serum and red cell enzyme polymorphisms in six Amerindian tribes

Data are presented on red cell and serum enzyme types in six Amerindian tribes in Central and South America of whom the Siriono, Chipaya and Jicaque are markedly inbred. The data obtained in three systems (AcP, PGM, 6PGD) show aberrant phenotype and gene frequencies in these three tribes by comparison with other Amerindian populations. Uniformity of the results was observed in the following red cell enzymes: AK, G6PD, PGM2, ADA and LDH.     

Marijuana and hyperthermia

The present paper reports the variability of PTC taste sensitivity among eight endogamous tribal populations inhabiting the Eastern Ghats of North Coastal Andhra Pradesh. It was compared with the genetic diversity of PTC taste sensitivity among tribal and caste populations of Andhra Pradesh. The tribal and caste groups present a relatively high genetic diversity, of which a major proportion is due to genetic differences within populations rather than that between populations. Castes show a higher heterogeneity than tribes, the difference being significant. The high genetic diversity found among Andhra populations may be attributed to social stratification and the practice of strict endogamy.     

Research in American Indian and Alaska Native communities: navigating the cultural universe of values and process

The National Institutes of Health's guidelines for recruiting ethnic minorities and women into clinical research have raised numerous questions among investigators. Highlighted in this article are a number of important issues for those researchers seeking to include American Indians and Alaska Natives in their studies; that is, defining the population of American Indians and Alaska Natives for inclusion in a study, participation of the tribes in research and approval by the Institutional Review Board, issues of confidentiality and anonymity of individuals and tribes, identifying potential benefits to American Indian and Alaska Native communities, and the importance of evaluating the scientific merit of a proposed study. Awareness and a commitment to ongoing education regarding these issues will enhance the quality and benefits of research among American Indian and Alaska Native people.     

Partial advance information and response preparation: inferences from the lateralized readiness potential

The mtDNA of most Native Americans has been shown to cluster into four lineages, or haplogroups. This study provides data on the haplogroup affiliation of nearly 500 Native North Americans including members of many tribal groups not previously studied. Phenetic cluster analysis shows a fundamental difference among 1) Eskimos and northern Na-Dene groups, which are almost exclusively mtDNA haplogroup A, 2) tribes of the Southwest and adjacent regions, predominantly Hokan and Uto-Aztecan speakers, which lack haplogroup A but exhibit high frequencies of haplogroup B, 3) tribes of the Southwest and Mexico lacking only haplogroup D, and 4) a geographically heterogeneous group of tribes which exhibit varying frequencies of all four haplogroups. There is some correspondence between language group affiliations and the frequencies of the mtDNA haplogroups in certain tribes, while geographic proximity appears responsible for the genetic similarity among other tribes. Other instances of similarity among tribes suggest hypotheses for testing with more detailed studies. This study also provides a context for understanding the relationships between ancient and modern populations of Native Americans.     

Headache--differential diagnosis and therapy]

Literature and folk wisdom have long linked depression and death; however, only recently have scientific studies examined the relation between them. Beginning in the 1970s, investigators compared mortality among patients treated for major depression and the general population. Nine of ten studies found an increased mortality from cardiovascular disease among depressed patients. However, such studies confound the relation between depression and its treatment. Community surveys circumvent this difficulty, but as these studies began to appear, other investigations revealed the strong association between depression and cigarette smoking, which made obvious a need to control for smoking. The first study to do this appeared in 1993, and not only did a relation between depression and mortality persist, but a relation between depression and the development of ischemic disease was revealed. In the past 2 years, six more community surveys have followed populations initially free of disease, and five have observed an increased risk of ischemic heart disease among depressed persons. Another research strategy is to start with subjects who have preexisting cardiovascular disease. Here, too, depression has consistently been associated with a worse outcome. In one well-designed study, patients with depression in the period immediately after a myocardial infarction were 3.5 times more likely to die than nondepressed patients. The basis of this association remains speculative. However, it is likely that the changes in the autonomic nervous system and platelets that are seen in depression account for a substantial portion of the association.     

Androstenedione conversion in human peripheral blood lymphocytes

Indigenous Indian groups comprise approximately 20% of Ecuador's population, the third largest percentage in all of Central or South America, yet immunogenetic data on these groups are lacking in the literature. In the course of population migration studies, sera collected from 65 Ecuadorians living in the northern province of Esmeraldas were typed for six GM and two KM markers. The study population consisted of 47 Cayapa Indians and 18 blacks of African origin, descendants of slaves imported into the area during the seventeenth century. The Cayapa demonstrated three GM phenotypes, two of which are common to other South American Indian tribes. The frequency of KM1 positive Cayapa Indians (63%) is similar to other South American Indian tribes, but is significantly greater than the Huaorani of eastern Ecuador (2%), the only other Ecuadorian Indian group for whom limited immunoglobulin allotype data are available (chi 2 = 35.8, P < 0.0001).     

Tribal-based cancer control activities among Alaska Natives: services and perceptions

Cancer has become a significant health problem in American Indian and Alaskan Native (AI/AN) communities. Despite the precipitous rise in cancer rates, limited data are available concerning cancer control services operative in these communities. To address this issue, a cross-sectional survey of all federally recognized tribes was undertaken to ascertain the breadth of cancer control activities offered and Tribal Health Directors perceptions of and priorities ascribed to cancer. This article presents responses given by AN Health Directors juxtaposed to those proffered by AI Health Directors. Nearly three-quarters (71%) of respondents perceived cancer rates to be increasing. Cancer was found to rank third, fifth among AI Health Directors, among seven health conditions when Directors were asked to rank their Tribe's commitment to confronting each one. Awareness of cancer as a public health concern coupled with competing health problems relegates cancer control activities to a lower priority. Findings underscore the need to elevate the issue of cancer in Indian Country as well as to educate investigators to become more sensitive and responsive to other Tribal health issues.     

Different molecular events result in low protein levels of mannan-binding lectin in populations from southeast Africa and South America

Previous studies have shown that three point mutations in exon 1 and a particular promoter haplotype of the mannan-binding lectin (MBL) gene lead to a dramatic decrease in the serum concentration of MBL. In this study, MBL genotypes and serum concentrations were determined in unrelated individuals in a population from Mozambique (n = 154) and in two native Indian tribes from Argentina (i.e., the Chiriguanos (n = 43) and the Mapuches (n = 25)). In both populations, the MBL concentrations were low compared with those found in Eskimo, Asian, and European populations. In Africans, the low serum concentrations were due to a high allele frequency (0.24) of the codon 57 (C) variant, which resulted in a high frequency of individuals with MBL deficiency (0.06), and were also due to the effect of a relatively high frequency (0.13) of low-producing promoter haplotypes. The low concentrations in the South American populations were primarily due to an extremely high allele frequency of the codon 54 (B) variant in both the Chiriguanos (0.42) and the Mapuches (0.46), resulting in high frequencies of individuals with MBL deficiency (0.14 and 0.16, respectively). In the search for additional genetic variants, we found five new promoter mutations that might help to elucidate the evolution of the MBL gene. Taken together, the results of this study show that different molecular mechanisms are the basis for low MBL levels on the two continents.     

Potassium currents in presynaptic hair cells of Hermissenda

Serum samples from eight endogamous Indian tribal populations of Madhya Pradesh (Dhurwa, Halba, Bhatra, Muria, Maria) and Orissa (Deshia Khond, Binjhal, Kisan) with a total of n = 731 unrelated individuals were typed for G1M (1,2,3,17), G3M (5,10,11,13,14,15,16,21, 26), and KM (1). In seven of these populations five different GM haplotypes were found: GM* 1,17;21,26; GM* 1,17;10,11,13,15,16; GM* 1,2, 17;21,26; GM* 1,3;5,10,11,13,14,26; and GM* 3;5,10,11,13,14,26. In the Kisan sample the haplotype GM* 1,2,17;21,26 is absent. The intergroup variability in the distribution of these haplotypes is considerable and statistically highly significant. The reasons for that can be attributed to the ethnohistory and to the genetic isolation of these eight endogamous tribal populations. The GM haplotype distribution pattern of all these groups is quite different from that of the non-tribal populations of India, whereas it is in good agreement with that of the so far tested other tribal populations from India. This can be explained by different origin and history of the Indian tribal and non-tribal populations. In the KM system, too, remarkable variability is seen in the distribution of phenotype and allele frequencies among the eight tribal populations under study.     

Use of randomly amplified polymorphic DNA markers for the genetic analysis of relatedness and diversity in chickens and turkeys

A study involving the use of random amplified polymorphic DNA (RAPD) was conducted to evaluate genetic polymorphism and relatedness within and among four chicken breeds: Araucona, Rhode Island Red, White Leghorn, and White Plymouth Rock, and two turkey populations, a long-term randombred and a commercial strain. A total of 60 random primers were used in the RAPD analyses. Forty-two of the 60 primers tested amplified patterns with at least one polymorphic fragment in one or more of the populations. Six of these 42 primers amplified polymorphic fragments in each of the six strains with a within- and between-population average band-sharing frequency of less than one but above zero (P < 0.05). Differences among the six primers for genetic distance (D) among populations were significant (P < 0.05). A consensus dendogram was therefore developed to show the phylogenetic relationships among the populations. As expected, estimates of D between populations were lowest within species and highest between species. The results provide evidence of the applicability of RAPD to determining genetic relatedness within and among different poultry populations and in developing reproducible markers useful in evaluating individual variation in chickens and turkeys.     

The incidence of systemic lupus erythematosus in North American Indians

The annual incidence (AI) of systemic lupus erythematosus (SLE) was determined in 75 highly inbred North American Indian tribes, a total of approximately 800,000 people, during the fiscal years 1971-1975. Seventy-two of the Indian tribes had an AI of SLE which was of similar magnitude to previously published studies from Sweden, Rochester (Minn.), Alabama, New York City, and San Francisco. However, Three tribes, the Crow, Arapahoe, and Sioux Indians, had a markedly elevated AI of SLE. These three tribes share common historical, geographic, and cultural characteristics. Further, they all reside in the northern half of the United States, in states that do not receive intense sun exposure, thereby eliminating photosensitivity as a major determinant of this increased prevalence. Finally, the AI of SLE in the Sioux Indians was highest for "full-blooded" members and lowest for genetic admixtures.     

Genetic variation within the Hereford breed of cattle

Genetic differentiation among Hereford populations from Britain, Ireland, Sweden, Canada and New Zealand together with six other beef breeds was assessed using blood type polymorphisms. Changes in the genetic structure of the British Hereford population over time were also examined. Loci surveyed were seven red cell antigen systems (A, B, C, F, L, S, Z), and two serum protein loci (transferrin and albumin). Within group variation was measured by the average expected heterozygosity, and between group relationships by genetic distance. There was significant genetic differentiation among Hereford populations from different countries. Differences between Hereford groups, however, were not as large as differences between breeds. There were also significance differences among British herds. The proportion of Canadian genes in the British 'hybrid' population was estimated to have increased from 0.42 (+/- 0.34) in the 1970s to 0.98 (+/- 0.11) in the 1990s. Canadian Hereford groups were found to be less heterozygous than other groups, and replacement of the British population with Canadian animals may lead to loss of variation. Breeding strategies that preserve original native genes in British Hereford populations should be considered by commercial breeders, in order to prevent the long-term loss of genetic variation within the breed.     

Mitochondrial DNA variation in Koryaks and Itel'men: population replacement in the Okhotsk Sea-Bering Sea region during the Neolithic

In this study, we analyzed the mitochondrial DNA (mtDNA) variation in 202 individuals representing one Itel'men and three Koryak populations from different parts of the Kamchatka peninsula. All mtDNAs were subjected to high resolution restriction (RFLP) analysis and control region (CR) sequencing, and the resulting data were combined with those available for other Siberian and east Asian populations and subjected to statistical and phylogenetic analysis. Together, the Koryaks and Itel'men were found to have mtDNAs belonging to three (A, C, and D) of the four major haplotype groups (haplogroups) observed in Siberian and Native American populations (A-D). In addition, they exhibited mtDNAs belonging to haplogroups G, Y, and Z, which were formerly called "Other" mtDNAs. While Kamchatka harbored the highest frequencies of haplogroup G mtDNAs, which were widely distributed in eastern Siberian and adjacent east Asian populations, the distribution of haplogroup Y was restricted within a relatively small area and pointed to the lower Amur River-Sakhalin Island region as its place of origin. In contrast, the pattern of distribution and the origin of haplogroup Z mtDNAs remained unclear. Furthermore, phylogenetic and statistical analyses showed that Koryaks and Itel'men had stronger genetic affinities with eastern Siberian/east Asian populations than to those of the north Pacific Rim. These results were consistent with colonization events associated with the relatively recent immigration to Kamchatka of new tribes from the Siberian mainland region, although remnants of ancient Beringian populations were still evident in the Koryak and Itel'men gene pools.     

Genetic diversity at six short tandem repeat loci within the state of Victoria, Australia

A new multiplex PCR system, developed by the Forensic Science Service (FSS) in the United Kingdom, permits the coamplification and typing of six short tandem repeat (STR) loci: HUMFGA, D8S1179, HUMTHO1, HUMvWA, D18S51, D21S11 and the sex determining marker Amelogenin. Data are presented on these six STRs for two populations in the state of Victoria, Australia: Caucasian and Asian. Whilst several worldwide databases are already available for the STR loci HUMTHO1 and HUMvWA, only relatively few databases exist for D8S1179, D18S51, D21S11 and HUMFGA. Allele frequencies at each locus displayed some fluctuations between the two populations. This is particularly so for HUMTHO1. Generally, however, the most common allele at each locus was the same in all populations, at all loci. A novel D8S1179 allele was found in Asians, provisionally identified as allele 19. Results for the six loci were compared with similar data from three UK resident populations: Caucasian, Afro-Caribbean and Asian (Indian/Pakistani) populations. These indicated that ethnically similar populations display similar allele frequencies, while the Australian Asian and UK Afro-Caribbean were found to be distinct.     

Studies of haptoglobin and transferrin types in four castes of the Panjab, Northern India

Serum samples from 197 individuals belonging to the caste groups of Brahmin (37), Bania (39), Khatri (73) and Jat (48) were electrophoretically examined for the haptoglobin and transferrin systems. Intercaste variation was considered and comparisons made between these North Indian populations and those in other parts of the Indian subcontinent. A single Khatri individual was typed CB.     

Clinico-morphological manifestations of genital tuberculosis in women

No previous studies have examined the influences of cultural background on the provision of contraceptive services to females under 16 years of age. A research project was undertaken to investigate any differences between general practitioners trained in the United Kingdom and those trained in the Indian sub-continent in relation to contraceptive service provision to females under 16 years of age. A self-completion postal questionnaire survey was distributed to 230 unrestricted principal general practitioners across Scotland. Subjects were identified from the Medical Register. Half of the sample consisted of all those working in Scotland who had been trained in the Indian sub-continent. The other half were a comparable group that had been trained in the United Kingdom and were selected by quasi-random quota sampling. The response rate was 57 per cent (131/230). General practitioners in the study who had trained in the Indian sub-continent were found to be significantly less likely to provide contraceptive services to a female under 16 years of age than those who had trained in the United Kingdom. Cultural background may be influential in general practitioner provision of contraceptive services to females below the legal age of consent for sexual intercourse. In order to obtain more conclusive evidence a larger study is necessary. Such investigations must be undertaken with appropriate sensitivity and social awareness.     

Expansion of bronchial epithelial cell populations by in vitro culture of explants from dysplastic and histologically normal sites

Most Colombian populations stem from the admixture of Caucasians, Amerindians and Negroids. In the world, these two latter ethnical groups show a significantly higher prevalence of epilepsy than the former one. We tested the hypothesis that the high prevalence of idiopathic epilepsy with generalized tonic clonic seizures found in the Antioquian population (Paisas), from Colombia, is due to their possible joint Negroid and Amerindian ethnic components. We have previously demonstrated that inheritance is the principal factor for developing epilepsy in this community. Analyses of racial admixture, heterogeneity between populations, genetic distance, and phyletic relationships were performed among epileptic and non epileptic samples from the Antioquian community. Also Caucasians, Spaniards, Basques, Jews, Chileans, Negroids, Amerindians and Mongoloids were included in the analysis. Four highly polymorphic blood systems were used as genetic markers: RH, MNS, ABO and FY. They were chosen because of their high discriminant power in these ethnic groups. In the population affected with idiopathic epilepsy, the estimated Negroid and Amerindian rates of admixture were low (3% and 14%, respectively). Although, these degrees of admixture can be explained due to common ancestral origins, the estimated proportion of Amerindian admixture in the epileptic affected population, was significantly higher than the estimated for the Non affected Antioquian population. The latter finding is consistent with the analysis of heterogeneity between populations that discriminated epileptic population from non epileptic Antioquian population (p < 0.05). Epileptic and non epileptic Paisas clustered in topology with Caucasians, very close to Spaniards and Basques and highly distant from Negroids and Amerindians. Thus, far, the origin of the high prevalence of idiopathic epilepsy in the Antioquian (Paisa) population cannot be explained by the hypothetical joint Negroid and Amerindian ethnical admixture, but using additional genetic markers and other methods of racial estimation of admixture it is necessary to corroborate if the Amerindian admixture component is significantly higher in the epileptic population than in the non epileptic Paisa population.     

A comparison of genetic variation in two sibling species pairs of haplodiploid insects

Sibling species pairs of sweat bees (Halictus confusus and H. tumulorum) and pine sawflies (Neodiprion pratti and N. maurus) were surveyed for genetic variability using enzyme electrophoresis. Levels of heterozygosity were found to be within the ranges earlier recorded for Hymenoptera. Expected heterozygosities were not significantly higher in the sawflies than in the sweat bees. Estimates of genetic identity between the sibling species were not lower than those generally found for diplodiploid insect species: no evidence was found for an increased rate of evolution in these haplodiploids. Genetic identity data among populations of H. confusus and between Halictus species were within the range expected for conspecific populations and sibling species, respectively. In Neodiprion all genetic distances were low but the two populations of N. pratti had similar genetic distances as each did to N. maurus, indicating the necessity for further systematic studies of the genus.