Neuroanatomical asymmetry in the canine brain

The brains of humans and non-human primates exhibit left/right asymmetries in grey matter morphology, white matter connections, and functional responses. These asymmetries have been implicated in specialized behavioral adaptations such as language, tool use, and handedness. Left/right asymmetries are also observed in behavioral tendencies across the animal kingdom, suggesting a deep evolutionary origin for the neural mechanisms underlying lateralized behavior. However, it is still unclear to what extent brain asymmetries supporting lateralized behaviors are present in other large-brained animals outside the primate order. Canids and other carnivorans evolved large, complex brains independently and convergently with primates, and exhibit lateralized behaviors. Therefore, domestic dogs offer an opportunity to address this question. We examined T2-weighted MRI images of 62 dogs from 33 breeds, opportunistically collected from a veterinary MRI scanner from dogs who were referred for neurological examination but were not found to show any neuropathology. Volumetrically asymmetric regions of gray matter included portions of the temporal and frontal cortex, in addition to portions of the cerebellum, brainstem, and other subcortical regions. These results are consistent with the perspective that asymmetry may be a common feature underlying the evolution of complex brains and behavior across clades, and provide neuro-organizational information that is likely relevant to the growing field of canine behavioral neuroscience.

The brain of the silver fox (Vulpes vulpes): a neuroanatomical reference of cell-stained histological and MRI images

Although the silver fox (Vulpes vulpes) has been largely overlooked by neuroscientists, it has the potential to serve as a powerful model for the investigation of brain-behavior relationships. The silver fox is a melanistic variant of the red fox. Within this species, the long-running Russian farm-fox experiment has resulted in different strains bred to show divergent behavior. Strains bred for tameness, aggression, or without selection on behavior present an excellent opportunity to investigate neuroanatomical changes underlying behavioral characteristics. Here, we present a histological and MRI neuroanatomical reference of a fox from the conventional strain, which is bred without behavioral selection. This can provide an anatomical basis for future studies of the brains of foxes from this particular experiment, as well as contribute to an understanding of fox brains in general. In addition, this can serve as a resource for comparative neuroscience and investigations into neuroanatomical variation among the family Canidae, the order Carnivora, and mammals more broadly.

The evolutionary neuroscience of domestication

How does domestication affect the brain? This question has broad relevance. Domesticated animals play important roles in human society, and substantial recent work has addressed the hypotheses that a domestication syndrome links phenotypes across species, including Homo sapiens. Surprisingly, however, neuroscience research on domestication remains largely disconnected from current knowledge about how and why brains change in evolution. This article aims to bridge that gap. Examination of recent research reveals some commonalities across species, but ultimately suggests that brain changes associated with domestication are complex and variable. We conclude that interactions between behavioral, metabolic, and life-history selection pressures, as well as the role the role of experience and environment, are currently largely overlooked and represent important directions for future research.

Adult and juvenile bearded capuchin monkeys handle stone hammers differently during nut-cracking

Wild bearded capuchin monkeys (Sapajus libidinosus) habitually use stone hammers to crack open palm nuts and seeds on anvils. This activity requires strength, balance, and precise movement of a large stone with respect to the item placed on an anvil. We explored how well young monkeys cope with these challenges by examining their behavior and the behavior of adults while they cracked palm nuts using a stone. Using video records, we compared actions of six juvenile (2-5 years) and six adult (7+ years) wild monkeys during their first 20 strikes with one unfamiliar ellipsoid, quartzite stone (540 g), and the outcomes of these strikes. Compared with adults, juveniles cracked fewer nuts, performed a more diverse set of exploratory actions, and less frequently placed one or both hands on top of the stone on the downward motion. Adults and juveniles displayed similar low frequencies of striking with a slanted trajectory, missing the nut, and losing control over the nut or stone after striking. These findings indicate that young monkeys control the trajectory of a stone adequately but that is not sufficient to crack nuts as effectively as adults do. Compared with juveniles, adults more quickly perceive how to grip the stone efficiently, and they are able to adjust their grip dynamically during the strike. Young monkeys develop expertise in the latter aspects of cracking nuts over the course of several years of regular practice, indicating that perceptual learning about these aspects of percussion occurs slowly. Juvenile and adult humans learning to use stones to crack nuts also master these features of cracking nuts very slowly.

HLA-DQB1, -DQA1, -DRB1 linkage disequilibrium and haplotype diversity in a Mestizo population from Guadalajara, Mexico

HLA-DQB1, -DQA1, and -DRB1 genes were typed by polymerase chain reaction with sequence-specific primer (PCR-SSP) in 159 healthy volunteers from 32 families living in Guadalajara, Mexico. Three-locus genotype data from all family members were used to infer haplotypes in 54 unrelated individuals of the sample, from which estimate of segregating haplotype frequencies and linkage disequilibrium (LD) between loci were computed. Genotype distributions were concordant with Hardy-Weinberg expectations (HWE) for all three loci, and allele distributions were similar to the ones observed in other Latin-American populations. Of the 56 distinct three-site (DQB1-DQA1-DRB1) haplotypes observed in the sample, the five most common (i.e., with frequencies of five counts or more) were: *0302-*0301-*04, *0201-*0201-*07, *0301-*0501-*14, *0402-*0401-*08, and *0501-*0101-*01. These common three-locus haplotypes also contributed to the majority of the significant two-locus linkage disequilibria of these three sites.

Skin reflectance in the Han Chinese and Tibetan populations

Genetic and environmental factors are involved in the determination of skin pigmentation in humans. With the recent development of statistical and genetic tools in mapping complex traits in humans, it is becoming feasible to utilize such methods in identifying genes involved in skin pigmentation. Furthermore, the use of new portable reflectance spectroscopy instruments such as the Photovolt ColorWalk colorimeter allows researchers to measure skin reflectance of a large number of subjects with ease and accuracy. We used a new portable instrument (Photovolt ColorWalk) to study the skin reflectance of 372 Han Chinese and 274 Tibetan individuals to establish background reflectance measurements of unexposed skin of the inner upper arm in these two populations. In addition, we explored the effect of various factors such as age and gender on skin reflectance.

Evidence of a sex-dependent association between the MSX1 locus and nonsyndromic cleft lip with or without cleft palate in the Chilean population

Prior studies have implicated an involvement of the Msx1 homeobox gene in cleft palate in mice and its homolog in humans (called MSX1 in the HOX7 gene, located on chromosome 4). In this study we present evidence of a sex-dependent association between MSX1 and non-syndromic cleft lip/palate (NSCLP) in the Chilean population. The sample included 73 NSCLP cases, 37 from multiplex families (Mx), 36 from simplex families (Sx), and 87 controls. Polymerase chain reaction amplification of the MSX1 intragenic microsatellite (CA)n-sequence shows significant (p = 0.035) differences in the allele frequencies between NSCLP-Mx males and control males. These differences are mainly due to frequency differences in allele *2 (173 base pairs) among cases (21.9%) and controls (13.2%). When the NSCLP cases are subdivided by sex and positive family history (Mx versus Sx), the Mx males (27.8%) as well as the total NSCLP-Mx cases (25.7%) showed significantly higher frequencies of allele *2, compared to controls (11.4% and 13.2%, respectively). Analysis of the genotype data indicates that the relative risk for NSCLP is greater for persons carrying allele *2 (i.e., odds ratio [OR] larger than 1), reaching significance for all Mx cases (OR = 2.67; 95% confidence interval [CI], 1.10 to 6.52) and even more pronounced for Mx males (OR = 3.33; 95% CI, 1.08 to 10.32). Taken together, these findings support the hypothesis that the genetic variation at the MSX1 locus is a predisposing gene involved in sex-dependent susceptibility to clefting and that it also differentiates simplex from multiplex families.

Gender and treatment differences in knowledge, health beliefs, and metabolic control in Mexican Americans with type 2 diabetes

PURPOSE

The purpose of this project was to describe metabolic control, knowledge, and health beliefs of Mexican Americans with type 2 diabetes.

METHODS

The study site was Starr County, Texas, a border community located on the Rio Grande River and bordering northern Mexico. Of the total sample of 360 persons, 252 agreed to participate in this intervention study and were randomized either to the treatment group or the control group that waited 1 year to begin the intervention.

RESULTS

The majority of individuals were Spanish-speaking females with a mean age of 54 years and a mean diabetes duration of 8 years. For those treated with diet only, males exhibited higher fasting blood glucose levels than females. Gender effects were seen for cholesterol level, with females exhibiting higher levels than males. Males expressed stronger perceptions of control and social support for diet. Bivariate relationships were found between acculturation and diabetes knowledge. The health belief subscales of control and impact on job together explained 16% of the variance in HbA1c values.

CONCLUSIONS

Males and females held differing beliefs about ability to control their diabetes and degree of social support for diet. The impact of gender differences on ability to integrate diabetes self-care and on effectiveness of diabetes programs has not been determined but should be considered in future research.

Estimation of nonpaternity in the Mexican population of Nuevo Leon: a validation study with blood group markers

A method for estimating the general rate of nonpaternity in a population was validated using phenotype data on seven blood groups (A1A2BO, MNSs, Rh, Duffy, Lutheran, Kidd, and P) on 396 mother, child, and legal father trios from Nuevo León, Mexico. In all, 32 legal fathers were excluded as the possible father based on genetic exclusions at one or more loci (combined average exclusion probability of 0.694 for specific mother-child phenotype pairs). The maximum likelihood estimate of the general nonpaternity rate in the population was 0.118 +/- 0.020. The nonpaternity rates in Nuevo León were also seen to be inversely related with the socioeconomic status of the families, i.e., the highest in the low and the lowest in the high socioeconomic class. We further argue that with the moderately low (69.4%) power of exclusion for these seven blood group systems, the traditional critical values of paternity index (PI > or = 19) were not good indicators of true paternity, since a considerable fraction (307/364) of nonexcluded legal fathers had a paternity index below 19 based on the seven markers. Implications of these results in the context of genetic-epidemiological studies as well as for detection of true fathers for child-support adjudications are discussed, implying the need to employ a battery of genetic markers (possibly DNA-based tests) that yield a higher power of exclusion. We conclude that even though DNA markers are more informative, the probabilistic approach developed here would still be needed to estimate the true rate of nonpaternity in a population or to evaluate the precision of detecting true fathers.

Symptom-related self-care of Mexican Americans with type 2 diabetes: preliminary findings of the Starr County Diabetes Education Study

Starr County, Texas, a Texas-Mexico border community, was the site of a study involving culturally-appropriate education and group support for Mexican Americans with type 2 diabetes. Data were collected from 63 subjects on frequency of diabetes-related symptoms during the previous month and on self-care symptom treatments. On average, subjects were 57-year-old females, diagnosed with diabetes for 10 years, and exhibiting HbA1c levels of 12.5%. Almost 50% experienced excessive urination, excessive thirst, shakiness/nervousness, and numbness and/or tingling in their extremities. More than 50% of those who experienced symptoms did not view them as serious. Only one subject checked blood sugar levels when symptoms occurred. Significantly higher mean glycosylated hemoglobin levels were found for individuals who experienced dizziness and/or chest pain compared with those who did not. A variety of self-care treatments were employed, including over-the-counter medications and home remedies.

Complex segregation analysis of facial clefting in Chile

Nonsyndromic cleft lip with or without cleft palate (CL/P) has an incidence of 1.5 per 1,000 live births in Chile, with 1.7 per 1,000 in males and 1.3 per 1,000 in females, which is nearly the same as the level found in Asian populations. The high rate of occurrence of CL/P in Chile is probably due to the presence of Amerindian genes in Chilean populations. Using the computer program PAP, a complex segregation analysis of CL/P was conducted for 67 multigeneration pedigrees from Chile, each ascertained from one affected proband. These pedigrees yielded 162 affected individuals and over 898 family members who were included in the analysis. The most parsimonious model of transmission indicated the presence of an autosomal dominant gene with reduced (20-25%) penetrance.

Boron levels in man: preliminary evidence of genetic regulation and some implications for human biology

Boron is a ubiquitous constituent of man's external environment. Levels of the element in human blood reflect both acute and chronic exposure, usually as dietary intake (food and drinking water). There is an absolute requirement for boron in vascular plants but evidence for biological essentiality in animals (including man) is limited. A high body burden of the element may be harmful, especially to young animals (including human neonates). Information on boron deficiency is scanty. It has been proposed that boron contributes to living systems by acting indirectly as a proton donor and that it exerts a particular influence on cell membrane structure and function. The present study examines the variation in blood levels within and between human sibships and provides some support for the possibility that boron metabolism is subject to genetic regulation.

Anticomplementary activity in serum samples from patients with acute parvovirus B19 infection

Of 65 serum samples submitted for diagnostic purposes which proved to be anti-complementary by complement fixation test, 49 were parvovirus B19 IgM positive. Forty four of the 49 serum samples were from patients with arthropathy. Acute parvovirus B19 infection should be suspected when a patient has symptoms of disease of the joints and the serum is anticomplementary.

Gas exchange in a three-compartment lung model analyzed by forcing sinusoids of N2O

A mathematical gas exchange model, using sinusoidal forcing functions of inert inspired gas (A. Zwart, R. C. Seagrave, and A. Van Dieren. J. Appl. Physiol. 41: 419-424, 1976), has been extended by us to include dead space (VD), a single alveolar compartment (VA) perfused with blood flow (Qp), and a shunt (Qs). In this new work we use N2O as the indicator gas in the mathematical model and in the experimental studies, in low enough concentrations [<6% (vol/vol)] to avoid anesthetic effects. Mathematical relationships between the inspired and expired N2O gas partial pressures, the blood gas N2O partial pressures, and their variation with forcing frequency are derived for a continuous ventilation uptake and a conventional anesthetic gas distribution model. We show that these gas and blood gas N2O relationships give direct derivation of cardiorespiratory parameters such as VA, Qp, the dead space-to-total ventilation ratio (VD/VT), and the shunt-to-total blood flow ratio (Qs/QT) without altering the subject's oxygenation and that they are essentially free from recirculation effects at high forcing frequencies > or = 2 min-1. Theoretical results from the model are presented for a wide range of forcing frequencies between 2 x 10(-2) and 10 min-1 (sinusoid periods 30-0.1 min), and these show that VA, Qp, and VD/VT can all be measured by N2O forcing frequencies > or = 1 min-1. We also present results from five animal studies, with an experimental inspired gas forcing frequency range of 0.125 to 2 min-1, which show qualitative agreement with the predictions of the continuous ventilation model. During these animal studies both mass spectrometric N2O respiratory gas measurements and intravascular polarographic arterial and mixed venous blood N2O partial pressure measurements were made, and examples of these in vivo measurements are presented, together with examples of the calculations derived from them.

Mortality of Mexican Americans with NIDDM. Retinopathy and other predictors in Starr County, Texas

OBJECTIVE

To determine the rate and risk factors of mortality in a cohort of Mexican Americans with NIDDM.

RESEARCH DESIGN AND METHODS

A cohort of 353 Mexican Americans with NIDDM were identified between 1981 and 1986. All individuals underwent extensive evaluations that included physical, historical, ophthalmological, and laboratory assessments. This cohort was followed prospectively for a mean of 8 yr. Follow-up included mortality surveillance, death certificate extraction, and a combination of annual and intermediate examinations.

RESULTS

The cohort experienced 67 mortality events. One-third of all deaths were premature < 65 yr of age) and most often were attributed to diseases of the heart (60.0%). In no case was diabetes listed as the cause of death, although it was listed as a contributing cause in 25.5% of cases. Men had a higher mortality rate than women. In both sexes, baseline retinopathy was identified as an important predictor of subsequent mortality. Mortality was significantly elevated in those with nonproliferative retinopathy and even further elevated in those with proliferative disease (relative risks of > or = 4 for proliferative disease).

CONCLUSIONS

Mexican Americans with NIDDM are experiencing premature and excessive mortality compared with the general population. The results clearly link microvascular complications with macrovascular disease, but this link is not explained by a more untoward profile of traditional cardiovascular risk factors. Retinopathy appears to serve as an important monitor of the progression of diabetes and when identified would warrant aggressive action to inhibit or slow the processes leading to subsequent mortality.

Characteristics of polymorphism at a VNTR locus 3' to the apolipoprotein B gene in five human populations

We have analyzed the allele frequency distribution at the hypervariable locus 3' to the apolipoprotein B gene (ApoB 3' VNTR) in five well-defined human populations (Kacharis of northeast India, New Guinea Highlanders of Papua New Guinea, Dogrib Indians of Canada, Pehuenche Indians of Chile, and a relatively homogeneous Caucasian population of northern German extraction) by using the PCR technique. A total of 12 segregating alleles were detected in the pooled sample of 319 individuals. A fairly consistent bimodal pattern of allele frequency distribution, apparent in most of these geographically and genetically diverse populations, suggests that the ApoB 3' VNTR polymorphism predates the geographic dispersal of ancestral human populations. In spite of the observed high degree of polymorphism at this locus (expected heterozygosity levels 55%-78%), the genotype distributions in all populations (irrespective of their tribal or cosmopolitan nature) conform to their respective Hardy-Weinberg predictions. Furthermore, analysis of the congruence between expected heterozygosity and the observed number of alleles reveals that, in general, the allele frequency distributions at this locus are in agreement with the predictions of the classical mutation-drift models. The data also show that alleles that are shared by all populations have the highest average frequency within populations. These findings demonstrate the potential utility of highly informative hypervariable loci such as the ApoB 3' VNTR locus in population genetic research, as well as in forensic medicine and determination of biological relatedness of individuals.

Genetic structure of the populations migrating from San Luis Potosi and Zacatecas to Nuevo León in Mexico

The Mexicans residing in the Monterrey metropolitan area in Nuevo León, Mexico, were grouped by generation and birthplace [Monterrey Metropolitan Area (MMA), San Luis Potosi (SLP), and Zacatecas (ZAC)] of the four grandparents to determine the extent of genetic variation within this population and the genetic differences, if any, between the natives living in the MMA and the immigrant populations from SLP and ZAC. Nine genetic marker systems were analyzed. The genetic distance analysis indicates that SLP and ZAC are similar to the MMA, irrespective of birthplace and generation. Gene diversity analysis (GST) suggests that more than 96% of the total gene diversity (HT) can be attributed to individual variation within the population. The genetic admixture analysis suggests that the Mexicans of the MMA, SLP, and ZAC, stratified by birthplace and generation, have received a predominantly Spanish contribution (78.5%), followed by a Mexican Indian contribution (21.5%). Similarly, admixture analysis, conducted on the population of Nuevo León and stratified by generation, indicates a substantial contribution from the MMA (64.6%), followed by ZAC (22.1%) and SLP (13.3%). Finally, we demonstrate that there is no nonrandom association of alleles among the genetic marker systems (i.e., no evidence of gametic disequilibrium) despite the Mestizo origin of this population.

Which measure of body fat distribution is best for epidemiologic research?

Multivariate associations were sought between risk factor levels (total cholesterol, high density lipoprotein (HDL) cholesterol, triglycerides, glucose, and systolic and diastolic blood pressures) and two sets of anthropometric variables (four circumferences and six skinfolds) to select a set of anthropometric indicators of body fat distribution that correlate most highly with risk of disease. Subjects were men (n = 285) and women (n = 672) from a study of gallbladder disease in a Mexican American population in Starr County, Texas, 1985-1986. The canonical correlations showed that circumferences (0.49-0.61) and skinfolds (0.42-0.60) were equally well correlated to risk factor levels independently of sex and age. Weights from the canonical analyses suggest that measurements at or above the waist and on the lower limb (thigh) are most heavily loaded toward risk (waist = highest risk; thigh = lowest risk). The simplest and most reliable index of body fat distribution for both sexes is the ratio of waist to thigh circumferences. The more commonly used waist/hip ratio proved more valid in women, but not in men. Simple skinfold indices of body fat distribution were more poorly correlated to risk factor levels than the corresponding circumference ratios. In women, body mass index and waist circumference by themselves did as well as body fat distribution indices in explaining variation in risk factors, suggesting the involvement of visceral fat in the body fat/body fat distribution disease relation.

Further observations on enhancement of the infectivity of Fusobacterium necrophorum by other bacteria

It had already been shown with a single virulent strain (A42) of Fusobacterium necrophorum that suspension of the fusobacteria in sub-lethal doses of broth cultures of other bacteria reduced the minimum infective dose (greater than 10(6) organisms) for mice by subcutaneous inoculation, sometimes to less than 10 organisms. The present study extended the known range of bacteria with strong infectivity-enhancing properties to include Bacillus cereus, Klebsiella oxytoca and Staphylococcus aureus; and those with weaker effect to include Bacillus subtilis, 'Bacteroides melaninogenicus', Clostridium sporogenes, Pasteurella haemolytica, and Proteus mirabilis. The study also showed that five further virulent strains of F. necrophorum closely resembled A42 in respect of striking susceptibility to infectivity enhancement by Escherichia coli. Actinomyces (Corynebacterium) pyogenes and S. aureus. One further strain (A6) of F. necrophorum resembled A42 in respect of strong infectivity enhancement by A. pyogenes, S. aureus, B. cereus and K. oxytoca but differed from it and the other five strains in being only slightly affected by E. coli. This work was a necessary prelude to the development of a method, based on infectivity enhancement, for the detection and isolation of F. necrophorum present in small numbers in heavily contaminated material such as faeces.

A sensitive method for isolating Fusobacterium necrophorum from faeces

The isolation of Fusobacterium necrophorum present in small numbers in heavily contaminated material such as faeces or soil is hampered by the lack of an efficient selective medium and by the high minimum infective dose of the organism. A sensitive method for the detection and isolation of faecal strains of F. necrophorum type A was based on the subcutaneous injection of faeces, suspended (5% w/v) in broth culture of Actinomyces (Corynebacterium) pyogenes or Staphylococcus aureus to increase fusobacterial infectivity, into mice pretreated with clostridial antitoxins. When necrobacillosis developed F. necrophorum was identified microscopically in tissue from the advancing edge of the lesion and isolated on a partly selective medium. The enhancement of fusobacterial infectivity produced by A. pyogenes and by S. aureus was high, but the latter was slightly the more efficient, enabling as few as 80 F. necrophorum organisms/g of faeces to be detected. Use of the method showed that 3 of 16 wallabies had F. necrophorum in their faeces at the time of examination. Numerous epidemiological applications are suggested.

Response time of the EG&G 1420B detector in a coherent anti-Stokes Raman spectroscopy system

Coherent anti-Stokes Raman spectroscopy measures combustion gas temperatures and molecular concentrations. This Letter reports the response times of our EG&G 1420B multichannel detector.

Ethnicity determination by names among the Aymara of Chile and Bolivia

The importance of surnames in genetic studies has been recognized for a century or so. While the ethnic affiliations of individuals are ordinarily established in genetic studies by admixture analysis based on gene frequencies, often there are implicit assumptions in these attempts that are difficult to validate in the absence of detailed ethnohistories. In northern Chile and western Bolivia, where genetic admixture has been known to occur among the Aymara Indians and Spanish Caucasoids, the naming pattern (parental patriand matrinyms) allowed us to classify individuals on the basis of the frequency of Aymara names into 9 'ethnic' groups. From a sample of 2525 individuals it is shown that admixture occurred in lineages nonrandomly, implying assortative mating of surnames. Admixture and genetic distance analysis on the basis of 31 genetic markers on approximately 1700 of these individuals reveals that there is a reasonable agreement of ethnic classification of individuals by name and phenotype data on genetic markers. The Aymara-named groups are shown to be predominantly Amerindian (89%) in their genetic profiles. Individuals whose current naming pattern is basically Spanish also exhibit a substantial fraction of genes of Amerindian origin (67%). Presence of some rare alleles not found in Amerindian or Spanish Caucasoids in the admixed groups suggest infiltration of Negroid genes in the past.

A compensation method for membrane-covered (Clark) electrodes

Membrane-covered electrodes (Clark electrodes) are widely used for monitoring blood gases, particularly PO2. A method of compensating for the inherently limited speed of response of Clark electrodes is presented. The theoretical response in the time domain is related to that in the frequency domain, and the latter is deduced from measurement of the former. Although the response functions are both infinite series, both responses are nevertheless completely defined by a single time parameter Te characteristic of the electrode under given measurement conditions. Practical verification was performed using electrodes in the double-pulsed mode, but the theory is applicable equally to direct-current-polarized and simply pulsed electrodes.

A digital system for generating dynamic sinusoidal gas concentration signals

A computer-controlled gas-mixing system is presented. It is capable of mixing four gases, the concentration of three of which will follow a path to be determined by the user. For our purposes the output O2 fraction is maintained constant and the levels of Ar and N2O vary sinusoidally and independently, with periods between 0.25 and 30 min. A fourth gas, N2 is necessary to make the sum of the individual fractions 100%. The system uses banks of between one and four solenoid valves each linked via a sonic choke to a common mixing chamber. A regime of pulse frequency modulation is employed. All calculations and timing of valve switching are performed by a dedicated microcomputer built for the purpose. The device has been used to provide respiratory gas forcing functions for a program of research in respiratory monitoring.

Effect of pump-laser linewidth on noise in single-pulse coherent anti-Stokes Raman spectroscopy temperature measurements

When N(2) is used as the probe molecule in a stable premixed propane-air flame near 2100 K, the standard deviation in single-pulse coherent anti-Stokes Raman spectroscopy (CARS) temperature measurements is shown to decrease by 20% as the pump-laser linewidth increases from </=0.02 to about 0.7 cm(-1). This effect is shown to be independent of the signal level at the detector array over the range considered. An instrument function that is useful in CARS convolution calculations is also presented.

Body circumferences as alternatives to skinfold measurements of body fat distribution in Mexican-Americans

The ratios of circumferences (waist/hip, waist/thigh) have been proposed in lieu of skinfold measurements for studies of obesity and body fat distribution. The purpose of this paper is to present our experience in measuring a series of body circumferences and skinfolds in an obese population, and seek the relationship between these two kinds of variables as indicators of fatness and body fat distribution using canonical correlation analysis. With this method, weighted vectors of circumferences on the one hand and skinfolds on the other, are formed in such a way that the correlation between the two sets of variables is maximized. The weights (regression coefficients) and their signs help us select the best combination of circumferences which describe a component of centralized obesity. Our experience showed that 21 percent of women would have been excluded from this multivariate analysis due to skinfolds what could not be measured (mainly due to poor fold definition). Few men were so excluded (6 per cent), and almost all circumferences could be measured in both sexes. A first canonical correlation was substantial (0.84 in women, 0.89 in men) and appeared to relate to level of fatness. A second canonical correlation was moderate (0.59 in women, 0.42 in men) and statistically significant (P less than 0.01) in both sexes. Only in women was it independent of age, but in both sexes it reflected differences in central and peripheral (especially lower limb) fat. The simple waist/thigh ratio correlated well with the second canonical variate (0.79 in women, 0.67 in men).(ABSTRACT TRUNCATED AT 250 WORDS)

Risk of postmenopausal hip fracture in Mexican American women

To assess the risk of hip fracture in Mexican Americans, the ethnicity of 80 women aged 50 years and over admitted with hip fractures to a Texas hospital was compared with that of age-matched women hospitalized for other reasons. The risk of fracture for Mexican Americans was only 35 per cent that of Whites (95% CI = 19 per cent, 65 per cent). This finding was confirmed in a chart survey performed in a second hospital population. These results suggest that Mexican American women may receive less potential benefit from preventive measures for hip fracture than Whites.

Genetic polymorphism and fertility parameters in the Aymara of Chile and Bolivia

To determine whether increased fitness in natural populations is associated with heterozygosity, several studies have attempted to correlate heterozygosity at one or a few genetic loci with fitness-related quantitative traits. The results have been equivocal at best. Furthermore, data on fertility-related parameters and the extent of genetic polymorphism at a large number of loci in man are quite scanty. This report examines the association of four fertility-related parameters (number of pregnancies, number of livebirths, number of children surviving at least one year and number of children alive at the time of the survey) with heterozygosity at 17 polymorphic immunological and biochemical systems in the Aymara of Chile and Bolivia. Women 45 years of age and above, on whom complete fertility histories and phenotype data are available, were included in the study (n = 190). None of the fertility parameters seem to be correlated with heterozygosity, as measured by the proportion of polymorphic loci. For some individual loci, however, an association between heterozygous state and fertility parameters exists. Even in these cases, heterozygosity did not always confer higher fertility. To see whether these negative results are due to heterogeneity in the data, the total sample was divided according to altitude of residence and ethnicity. The conclusions remained the same, indicating that the lack of association of these fertility parameters with genetic polymorphism is not due to population heterogeneity alone. Reproductive fitness differentials, therefore, were not detectable in the Aymara by heterozygosity determined by the polymorphic genetic systems scored by serological and electrophoretic techniques.

Immunoglobulin (Gm and Km) allotypes in the Aymara of Chile and Bolivia

Immunoglobulin (Gm and Km) allotype and haplotype frequencies are presented for 1707 individuals from Northern Chile and Western Bolivia, subdividing them by ethnicity and altitude of residence. The haplotype distribution of Gm as well as Km loci in these populations suggest that in almost all of the ethnicity x altitude subdivisions of this population considerable admixture of Amerindian and Caucasian genes have occurred. The haplotype frequency heterogeneity and the analysis of departure from Hardy-Weinberg expectations demonstrate that while some local variation in haplotype frequencies at the Gm and Km loci exists in this region, there is no clear evidence suggesting that the pattern of variation is due to an adaptation to the hypoxia of altitude. We conclude that such differences in haplotype frequencies are probably due to random genetic drift and differential admixture of Amerindian and Caucasian genes that have occurred in the past.

Diabetes among Mexican Americans in Starr County, Texas

An increasing body of evidence suggests that diabetes mellitus constitutes a major health burden among the Mexican-American population. For example, county-wide death rates in Texas attributable to diabetes from 1970-1981 range from 2.5-52.0 diabetes deaths per 1000 total deaths with the highest rates generally occurring in counties whose populations are more than 75% Spanish ancestry. To assess the prevalence and morbidity of noninsulin-dependent diabetes mellitus among Mexican Americans, 14% of the Starr County, Texas, population (97% Mexican-American) was randomly sampled. The reference population, sampling strategy, and screening results are described. Age-specific prevalences of diabetes for males ranged from 0% in males aged 15-24 years to 17.6% in those above 75 years of age. Rates for females ranged from 0.4% in those aged 15-24 years to a high of 19.0% in the 55- to 64-year age group. In both sexes, the rates are relatively low for persons under age 45 with a sharp increase in those aged 45-54 years and high rates prevailing in the older age groups. Comparisons of the rates in Starr County to those of the general US population indicate a two- to fivefold greater risk in Starr County. In terms of impact on this community, these results imply that over 50% of individuals older than 35 years are directly affected by diabetes by virtue of their having the disease or by being a first-degree relative of a diabetic.

Genetic components of variations of red cell glycolytic intermediates at two altitudes among the South American Aymara

Red cell haemoglobin (Hb), haematocrit (Ht), 2,3-diphosphoglycerate (DPG), and adenosine triphosphate (ATP) levels were measured in 876 individuals from six villages at two altitude levels (altiplano and coast) of the Departmento de Arica of Northern Chile. Of these, data on 761 individuals are subjected to analysis to search for the evidence of genetic adaptation to a hypoxic environment at a high altitude. Total phenotypic variance for each of the variables is higher at the altiplano as compared to their counterparts at the coastal level. Data on 1127 pairs of relatives of six degrees of relationships are used to determine the genetic component of variation in each of these four traits. To a certain extent the larger familial correlations as well as higher variances at altiplano are explained by the apparent assortative mating (which may again be due to their restricted population size) at the higher elevation. Yet, at least in three variables (Hb, Ht, and DPG) no reduction in the additive genetic component of variation is noticed at the higher altitude. ATP seems to have the highest degree of genetic component of variance, particularly at the coastal level. Some implications of these results are discussed in the light of their roles in the glycolytic pathway.

Circadian heart rate rhythmicity: comparison between an Eskimo and other population groups

This brief communication reports the results of 24-ambulatory cardiac monitoring of a Bering Strait Eskimo population and compares the findings with 3 other populations. Similar heart rate rhythmicity and almost identical acrophases are found in the Eskimo, Aymara Indian and French populations. However, the Alaskan Eskimo and Aymara Indian 24-h means vary by approximately 15 beats/min, with the American population between these two. The mesor displays most radical differences.

2,3-Diphosphoglycerate and night vision

Recovery of night vision at altitude has been examined in relationship to changes of 2,3,diphosphoglycerate (DPG). It appears that, if DPG influences night adaptation, its effect is small. Inter-individual variability is large, both in terms of DPG and performance on the MESOP, the device used to measure dark adaptation.

The Multinational Andean Genetic and Health Program. IX. Gene frequencies and rare variants of 20 serum proteins and erythrocyte enzymes in the Aymara of Chile

Electrophoretic variants at 22 genetic loci in the Aymara, mestizo, and Spanish populations of northern Chile are presented, and their possible role in adaptation to hypoxic environments are discussed. Some apparently unique variants were found.

The Aymara of Western Bolivia. IV. Gene frequencies for eight blood groups and 19 protein and erythrocyte enzyme systems

A total of 315 individuals, mainly of Aymara origin, from western Bolivia were examined for genetic variation at eight red cell antigen and 19 serum protein and red cell enzyme loci. The gene frequencies for polymorphic loci and the discovery of several rare variants are discussed in terms of previous work among the Aymara and the closely related Quechua. The effect of inclusion of related individuals in the sample on gene frequency, variance of gene frequency and genetic distance, is discussed.

The Aymara of Western Bolivia. II. Maxillofacial and dental arch variation

Maxillofacial and dental arch dimensions of the Bolivian Aymara population are age and sex dependent. Interpopulational comparisons reveal these dimensions to differ from those seen in Aleuts, Australian aborigines, and Swedes, but to be similar to those of the indigenous Taiwanese. Finally, these dimensions are not the same in Aymara of unmixed ancestry, and Mestizos residing in the same villages.

High altitude, indigenous origin, and continuous cardiac monitoring

Tape monitoring of the electrocardiogram among ambulant individuals with and without cardiac disease has been practicable for some years now. It has, however, found greater acceptance and utilization in diagnosis, early detection of silent ischemic heart disease (17), and the evaluation of the effectiveness of different dysrhythmia treatment modalities than as a means to examine differences in cardiovascular response to environmentally stressful situations. This study illustrates its practicability under field conditions substantially more rigorous than in most prior uses, and its applicability to our further understanding of the cardiovascular changes associated with adaptation to the hypoxia of altitude.