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PubMed2002

Hispano-Indian admixture in Paraguay studied by analysis of HLA-DRB1 polymorphism.

The genetic polymorphism of the Paraguayan population results from the admixture between South American Indians named Guaranis and Spaniards. In order to evaluate the genetic predominance in the Paraguayan population, we typed 50 healthy Paraguayans for HLA-DRB1 by molecular biology and compared their HLA-DRB1 polymorphism to that of the Guaranis and of two Spanish populations. Six significant differences of alleles frequencies were observed between Paraguayans and Guaranis--DRB1*01, 06 (13, 14), 15, 16, 07--whereas only one difference was observed with the Spaniards (DRB1*14). The DRB1*14 frequency was higher in Paraguayan than in the Spanish populations essentially due to the presence of DRB1*1402 related alleles (1402,06,13). These alleles are extremely rare in the Spanish populations whereas frequent in the Guaranis from Brazil and in South American Indian tribes living in the lymitrophe regions of Paraguay (Toba, Wichi and Terena). Thus, the presence of the DRB1*1402 related alleles (6%) in the Paraguayan population constitutes the major Indian contribution to the HLA-DR polymorphism of the Paraguayan population. The genetic distances between Paraguayans and the two Spanish populations were closer (.494 and .415) than that between Paraguayans and Guaranis (.958). Altogether these results suggest the predominance of the Spanish genetic in the Paraguayan population. Historical events are discussed to explain this predominance.

Alleles↗

PubMed1997

Spectrofluorometric estimation of aspirin and dipyridamole in pure admixtures and in dosage forms.

Aspirin and dipyridamole in pure admixtures and in dosage forms have been estimated by spectrofluorometry. Aspirin (2-12 mcg ml-1) was estimated in 1% v/v glacial acetic acid in chloroform using 246 and 345 nm for excitation and emission respectively. Dipyridamole (2-12 mcg ml-1) has been estimated in chloroform using 420 nm for excitation and 475 nm for emission. The non-interference of the excipients as well as the drugs in the estimation of each other, as evidenced by the results, indicate that this method may be used for the routine estimation of aspirin and dipyridamole in tablet preparations.

Aspirin↗

PubMed1999

Validation of a reversed-phase LC method for quantitative analysis of intravenous admixtures of ciprofloxacin and metronidazole.

The admixture ciprofloxacin-metronidazole is nowadays well known as a clinical tool when anaerobic organisms are involved. The stability of ciprofloxacin with metronidazole depends on several variables and this has been scarcely studied. Thus, the aim of this study was the search for a specific, precise and accurate method that would allow the quantification of ciprofloxacin in the presence of metronidazole. The reversed-phase liquid chromatography method is the analytical technique that has proved to be the most adequate for stability and compatibility studies of this mixture. This method was shown to be linear (r>0.999) in the range of concentrations of this study chosen, between 80 and 120% of the concentration of the commercial formulation. It showed precision with a repeatability (within-day) of 0.62% and reproducibility (between-day) of 1.14%, accuracy expressed as recovery percentage.

Anti-Infective Agents↗

PubMed1999

Analysis of low concentration sufentanil citrate/bupivacaine hydrochloride admixtures, using solid phase extraction followed by high-performance liquid chromatography.

A method has been developed for the quantitative determination of low concentrations of sufentanil citrate (1.0 microg/ml), in the presence of bupivacaine hydrochloride (0.125%), in the quality control of pharmaceutical preparations. The main problem in analysis of this combination is the low concentration of sufentanil citrate in the presence of relatively high concentrations of bupivacaine hydrochloride. This paper describes the validation of a HPLC method of sufentanil citrate in an admixture with bupivacaine hydrochloride using solid phase extraction (SPE). The optimized method shows good linearity, precision and accuracy. The limits of detection (0.09 microg/l) and quantification (0.29 microg/l) for sufentanil citrate are lower than the maximal accepted limits. This method is currently used in stability studies.

Analgesics, Opioid↗

PubMed2000

Probable ancestors of Hungarian ethnic groups: an admixture analysis.

The history of Hungary starts in the 9th century with the arrival of the Magyars in the Carpathian Basin. They spoke, like modern Hungarians, an Uralic language belonging to the Finno-Ugric language group. Their original composition probably included Iranian and Turkish people, while other populations were already present in the territory (Avars, Slavs, Germans). Some of the Hungarian ethnic groups claim to be descendants of ancient Magyars settlers (such as the Orség), others of Huns, Turks or Iranians. We collected and compared the previously published gene frequencies of eight ethnic groups and seven hypothetical ancestral populations, including Uralics, applying a model of admixture. The results, most of which confirm historical hypotheses or the oral tradition, show that only one ethnic group (Orség) highly resembles the Uralic population.

Emigration and Immigration↗

PubMed2005

Admixture analysis of age at onset in obsessive-compulsive disorder.

BACKGROUND: Age at onset (AAO) has been useful to explore the clinical, neurobiological and genetic heterogeneity of obsessive-compulsive disorder (OCD). However, none of the various thresholds of AAO used in previous studies have been validated, and it remains an unproven notion that AAO is a marker for different subtypes of OCD. If AAO is a clinical indicator of different biological subtypes, then subgroups based on distinct AAOs should have separate normal distributions as well as different clinical characteristics. METHOD: Admixture analysis was used to determine the best-fitting model for the observed AAO of 161 OCD patients. RESULTS: The observed distribution of AAO in OCD is a mixture of two Gaussian distributions with mean ages of 11.1 +/- 4.1 and 23.5 +/- 11.1 years. The first distribution, defined by early-onset OCD, had increased frequency of Tourette's syndrome and increased family history of OCD. The second distribution, defined by late-onset OCD, showed elevated prevalence of general anxiety disorder and major depressive disorder. CONCLUSIONS: These results, based on a statistically validated AAO cut-off and those of previous studies on AAO in OCD, suggest that AAO is a crucial phenotypic characteristic in understanding the genetic basis of this disorder.

Adolescent↗

PubMed2005

Stimulating effect of graphite admixture on hydrogen sorption-desorption properties of mechanically activated titanium powder.

The effect of graphite admixture on hydrogen sorption-desorption properties of mechanically activated electron microscopy, temperature-programmed reaction, and temperature-programmed desorption techniques. The major effect of graphite addition was found to be the formation of microporous carbon matrix particles containing randomly distributed titanium particles only several nanometers in diameter. This powder architecture enhances hydrogen transport to the titanium surface without hindrances and promotes titanium-hydrogen interaction by modifying the titanium surface and subsurface layers with interstitial carbon atoms.

Journal Article↗

PubMed2005

Quantum-admixture model of high-spin <--> low-spin transition for ferrous complex molecules.

A quantum-admixture model for the d(6) configuration ferrous complex molecules with the high-spin <--> low-spin transition has been established by using the unified crystal-field-coupling (UCFC) scheme. A general study has been made on the spin transition of octahedrally coordinated d(6) complexes, and a special application has been given to an Fe(II) compound Fe(II)(TRIM)(2)(PhCO(2))(ClO(4)). The results show the following: (i) The quantum picture of the spin transition of a d(6) system, such as Fe(II), is much more complex than a simple transition between the pure (5)T(2g) and (1)A(1g) states as usually understood. In practice, owing to spin-orbit coupling, spin is no longer a good quantum number and there is no longer a pure (5)T(2g) or (1)A(1g) state. Each of them splits into substates and each substate is a linear combination of various multiplets. The high-spin --> low-spin transition of an octahedrally coordinated d(6) ion is practically the crossover of the two lowest substates of (5)T(2g) at the critical point. (ii) At the spin-transition critical point the magnetic moment mu(eff) approximately 5.22 mu(B), which is obviously different from the simple average of the mu(eff) values of high-spin and low-spin states but near the saturation value. (iii) The calculation of the effective molecular magnetic moment mu(eff) for an octahedrally coordinated Fe(II) ion shows that the mu(eff)-T curve is in good agreement with Lemercier et al.'s experiment and both the low-spin value mu(eff) = 0.51 mu(B) and the high-spin value mu(eff) = 5.4 mu(B) are comparable with the experimental values 0.76 mu(B) and 5.4 mu(B), respectively. (iv) The T dependence of the crystal field parameter Dq in the spin-transition region is approximately linear.

Ferrous Compounds↗

PubMed1986

The ecological genetics of introduced populations of the giant toad, Bufo marinus. IV. Gene flow estimated from admixture in Australian populations.

Allele frequency variation is described at nine polymorphic enzyme loci in 21 samples from populations of the introduced Giant Toad, Bufo marinus, in the region of Townsville in north Queensland, Australia. Some of these populations appear to have been established through the introgression of other populations that previously had been isolated. Comparisons of allele frequencies at three polymorphic loci between the introgressed populations and the original populations are used to obtain admixture estimates. These are used to estimate a rate of gene flow among the populations of approximately 2 km/year. This is consistent with an estimate based on the rate at which Bufo marinus has colonised new areas in Australia when discontinuities in the pattern of this colonisation are taken into account. The estimate of gene flow is combined with published data on population density to estimate neighbourhood size. The estimate obtained is substantially greater than the effective population size estimate determined previously from data on allele frequency variances in other populations. This discrepancy is most likely due to inaccuracies in the population density estimates, to underestimates of the extent of offspring number variance and perhaps to occasional departures from sex ratio parity. It has important implications for the study of the genetic structure of populations which are discussed.

Alleles↗

PubMed2005

Mapping by admixture linkage disequilibrium: advances, limitations and guidelines.

Mapping by admixture linkage disequilibrium (MALD) is a theoretically powerful, although unproven, approach to mapping genetic variants that are involved in human disease. MALD takes advantage of long-range haplotypes that are generated by gene flow among recently admixed ethnic groups, such as African-Americans and Latinos. Under ideal circumstances, MALD will have more power to detect some genetic variants than other types of genome-wide association study that are carried out among more ethnically homogeneous populations. It will also require 200-500 times fewer markers, providing a significant economic advantage. The MALD approach is now being applied, with results expected in the near future.

Chromosome Mapping↗

PubMed2026

Ancestry, admixture, and pathogens in contemporaneous Neolithic farmers and foragers on the Island of Gotland.

Two archaeological cultural complexes; the Neolithic Funnelbeaker culture (FBC) and the Pitted ware culture (PWC), coexisted on Gotland for over 500 years, between ~3300 and 2800 calBCE. The ancestry of the FBC farmers and PWC marine foragers largely aligns with European Neolithic Farmers and European Mesolithic foragers, respectively, but the direct interactions between the groups on Gotland is not understood. We present a Middle Neolithic (MN) high-coverage genome and a Late Neolithic (LN) low-coverage genome from the Ansarve FBC dolmen. We investigate ancestry, admixture, and pathogens among these MN farmers (n = 6), foragers (n = 19), and the LN individual. We find that recent gene-flow between farmers and foragers could have taken place, although most gene-flow happened prior to their coexistence on the island. We also find evidence of different Yersinia pestis strains in the three cultural groups, showing that the pestis was widespread among groups with different subsistence strategies.

Humans↗

PubMed2004

Admixture, migrations, and dispersals in Central Asia: evidence from maternal DNA lineages.

Mitochondrial DNA (mtDNA) lineages of 232 individuals from 12 Central Asian populations were sequenced for both control region hypervariable segments, and additional informative sites in the coding region were also determined. Most of the mtDNA lineages belong to branches of the haplogroups with an eastern Eurasian (A, B, C, D, F, G, Y, and M haplogroups) or a western Eurasian (HV, JT, UK, I, W, and N haplogroups) origin, with a small fraction of Indian M lineages. This suggests that the extant genetic variation found in Central Asia is the result of admixture of already differentiated populations from eastern and western Eurasia. Nonetheless, two groups of lineages, D4c and G2a, seem to have expanded from Central Asia and might have their Y-chromosome counterpart in lineages belonging to haplotype P(xR1a). The present results suggest that the mtDNA found out of Africa might be the result of a maturation phase, presumably in the Middle East or eastern Africa, that led to haplogroups M and N, and subsequently expanded into Eurasia, yielding a geographically structured group of external branches of these two haplogroups in western and eastern Eurasia, Central Asia being a contact zone between two differentiated groups of peoples.

Africa↗

PubMed2003

Admixture analysis of South Asian cattle.

We present population genetic analysis of microsatellite variation in seven Bos indicus cattle breeds from a variety of locations in South Asia. This is the first such study focusing within this area, which is one of the postulated centres of origin of domestic cattle. An estimate of the influence of Bos taurus ancestry was carried out using three approaches: by the systematic selection of population-associated alleles for B. taurus and examination of their frequency; by examining the truncation of genetic distances from European populations; and by a model-based Bayesian admixture analysis. These analyses revealed a B. taurus influence in the Indian subcontinent; part of a gradation which stretches from Europe through the Near East towards Indian and which may be of ancient origin.

Alleles↗

PubMed2006

Admixture in European Populus hybrid zones makes feasible the mapping of loci that contribute to reproductive isolation and trait differences.

The use of admixed human populations to scan the genome for chromosomal segments affecting complex phenotypic traits has proved a powerful analytical tool. However, its potential in other organisms has not yet been evaluated. Here, we use DNA microsatellites to assess the feasibility of this approach in hybrid zones between two members of the 'model tree' genus Populus: Populus alba (white poplar) and Populus tremula (European aspen). We analyzed samples of both species and a Central European hybrid zone (N=544 chromosomes) for a genome-wide set of 19 polymorphic DNA microsatellites. Our results indicate that allele frequency differentials between the two species are substantial (mean delta=0.619+/-0.067). Background linkage disequilibrium (LD) in samples of the parental gene pools is moderate and should respond to sampling schemes that minimize drift and account for rare alleles. LD in hybrids decays with increasing number of backcross generations as expected from theory and approaches background levels of the parental gene pools in advanced generation backcrosses. Introgression from P. tremula into P. alba varies strongly across marker loci. For several markers, alleles from P. tremula are slightly over-represented relative to neutral expectations, whereas a single locus exhibits evidence of selection against P. tremula genotypes. We interpret our results in terms of the potential for admixture mapping in these two ecologically divergent Populus species, and we validate a modified approach of studying genotypic clines in 'mosaic' hybrid zones.

Alleles↗

PubMed2006

Individual-based assessment of population structure and admixture in Austrian, Croatian and German draught horses.

All over Europe, the number of draught horses has decreased drastically during the last 50 years. As a prerequisite for efficient management decisions, we analysed the conservation status in Austrian (Noriker Carinthia - NC, Noriker Salzburg - NS), Croatian (Croatian Coldblood - C, Posavina horse - P) and German (Altmaerkisch Coldblood - A, Black Forest horse - BF, Mecklenburg Coldblood - M, Rhenish German Draught horse - R, Saxon Thuringa Coldblood - ST, Schleswig Draught horse - Sch, South German Coldblood - SG) draught horses (434) using multilocus genotypic information from 30 (effectively 27) microsatellite loci. Populations located in areas with less intensive agricultural production (C, NC, NS, P and SG) had greater diversity within the population and estimated effective population size than A, BF, Sch, M, R and ST populations. The PCA plots revealed that populations form five separate groups. The 'Noriker' group (NC, NS and SG) and the 'Rhenish' group (A, M, R and ST) were the most distinctive (pairwise F(ST) values ranged from 0.078 to 0.094). The 'Croatian' group (C and P) was in the centre, while the BF and Sch populations formed two out-groups. A posterior Bayesian analysis detected further differentiation, mainly caused by political and geographical factors. Thus, it was possible to separate the South German Coldblood from the Austrian Noriker population where no subpopulation structure was detected. The admixture analysis revealed imprecise classification between C and P populations. A small but notable separation of R from A, M and ST populations was detected, while Sch and BF populations remained as out-groups. The information obtained should aid in making efficient conservation decisions.

Animals↗

PubMed1978

Revised standards for normal resting dead-space volume and venous admixture in men and women.

1. Data have been combined from three previous series to provide revised standards for the prediction of physiological dead-space volume (VD), arterial oxygen tension (Pa,O2), alveolar-to-arterial oxygen-tension difference (PAO2--Pa,O2) and venous admixture fraction (QVa/Qt) in the sitting position. 2. These standards, based on measurements in 96 healthy men and women aged from 20 to 74 years, largely confirm conclusions drawn from the first series of 48 subjects. 3. VD is best predicted on age, height, tidal volume and the reciprocal of respiratory frequency. Pa,O2,(PA,O2--Pa,O2) and Qva/Qt are adequately predicted on age alone.

Adult↗

PubMedDate not supplied

Distributions of HLA-DRB1/DQB1 alleles and haplotypes in the north-eastern Thai population: indicative of a distinct Thai population with Chinese admixtures in the central Thais.

The phenotype and gene frequencies of HLA class II alleles were studied in the North-eastern Thai population. Blood samples were collected from 100 unrelated healthy North-eastern Thais. The HLA-DRB1 and DQB1 genes were typed using the polymerase chain reaction--sequence specific primer (PCR-SSP) and polymerase chain reaction--sequence specific oligonucleotide probe (PCR-SSO) techniques. Twenty-six HLA-DRB1 and 11 DQB1 alleles were found in this population. DRB1*1202, 1502, 0405 and DQB1*0502/0504, 0301/0304 alleles were commonly found. Linkage disequilibrium analysis suggested the existence of 13 DR-DQ haplotypes. The DRB1*1502-DQB1*0501 haplotype was the most common. The DRB1*1106-DQB1*0301/0304 haplotype was found only in North-eastern Thais and not in other Thai populations. Comparative analysis of the HLA-DR/DQ alleles revealed differences in the distributions of these alleles amongst different ethnic groups. Interestingly, the distributions of HLA class II alleles in Central Thai, North-eastern Thai and Southern Chinese populations are similar. However, it appears that the distribution in the Central Thais is a mixture of those in Southern Chinese and North-eastern Thais, suggesting the existence of Thai-Chinese admixtures in the Central Thai population. This study provides basic information for further studies of the MHC in anthropology, organ transplantation and disease susceptibility in the North-eastern Thai population.

Alleles↗

PubMed1999

Microsatellite analysis of sperm admixture in honeybee.

Sperm usage was investigated in an instrumentally inseminated honeybee queen. Her progeny were examined in the first 3 months of the egg-laying period using a microsatellite marker. Frequencies of different subfamilies differed significantly from one month to another. However, there was no evidence for sperm displacement or sperm precedence of a specific male in the worker progeny. The variance of subfamily proportions decreased over time suggesting that sperm admixture in the spermatheca was incomplete at the beginning of the egg-laying period of the queen and improved progressively during the first months after mating.

Animals↗