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Biomedical subjects

M C Goldstein

Publications and source records attributed to M C Goldstein.

At least 19 recordsLinked to original sources
PubMed1998

Hemoglobin concentration of high-altitude Tibetans and Bolivian Aymara.

Elevated hemoglobin concentrations have been reported for high-altitude sojourners and Andean high-altitude natives since early in the 20th century. Thus, reports that have appeared since the 1970s describing relatively low hemoglobin concentration among Tibetan high-altitude natives were unexpected. These suggested a hypothesis of population differences in hematological response to high-altitude hypoxia. A case of quantitatively different responses to one environmental stress would offer an opportunity to study the broad evolutionary question of the origin of adaptations. However, many factors may confound population comparisons. The present study was designed to test the null hypothesis of no difference in mean hemoglobin concentration of Tibetan and Aymara native residents at 3,800-4,065 meters by using healthy samples that were screened for iron deficiency, abnormal hemoglobins, and thalassemias, recruited and assessed using the same techniques. The hypothesis was rejected, because Tibetan males had a significantly lower mean hemoglobin concentration of 15.6 gm/dl compared with 19.2 gm/dl for Aymara males, and Tibetan females had a mean hemoglobin concentration of 14.2 gm/dl compared with 17.8 gm/dl for Aymara females. The Tibetan hemoglobin distribution closely resembled that from a comparable, sea-level sample from the United States, whereas the Aymara distribution was shifted toward 3-4 gm/dl higher values. Genetic factors accounted for a very high proportion of the phenotypic variance in hemoglobin concentration in both samples (0.86 in the Tibetan sample and 0.87 in the Aymara sample). The presence of significant genetic variance means that there is the potential for natural selection and genetic adaptation of hemoglobin concentration in Tibetan and Aymara high-altitude populations.

Adaptation, Physiological↗
PubMed1997

Ventilation and hypoxic ventilatory response of Tibetan and Aymara high altitude natives.

Newcomers acclimatizing to high altitude and adult male Tibetan high altitude natives have increased ventilation relative to sea level natives at sea level. However, Andean and Rocky Mountain high altitude natives have an intermediate level of ventilation lower than that of newcomers and Tibetan high altitude natives although generally higher than that of sea level natives at sea level. Because the reason for the relative hypoventilation of some high altitude native populations was unknown, a study was designed to describe ventilation from adolescence through old age in samples of Tibetan and Andean high altitude natives and to estimate the relative genetic and environmental influences. This paper compares resting ventilation and hypoxic ventilatory response (HVR) of 320 Tibetans 9-82 years of age and 542 Bolivian Aymara 13-94 years of age, native residents at 3,800-4,065 m. Tibetan resting ventilation was roughly 1.5 times higher and Tibetan HVR was roughly double that of Aymara. Greater duration of hypoxia (older age) was not an important source of variation in resting ventilation or HVR in either sample. That is, contrary to previous studies, neither sample acquired hypoventilation in the age ranges under study. Within populations, greater severity of hypoxia (lower percent of oxygen saturation of arterial hemoglobin) was associated with slightly higher resting ventilation among Tibetans and lower resting ventilation and HVR among Aymara women, although the associations accounted for just 2-7% of the variation. Between populations, the Tibetan sample was more hypoxic and had higher resting ventilation and HVR. Other systematic environmental contrasts did not appear to elevate Tibetan or depress Aymara ventilation. There was more intrapopulation genetic variation in these traits in the Tibetan than the Aymara sample. Thirty-five percent of the Tibetan, but none of the Aymara, resting ventilation variance was due to genetic differences among individuals. Thirty-one percent of the Tibetan HVR, but just 21% of the Aymara, HVR variance was due to genetic differences among individuals. Thus there is greater potential for evolutionary change in these traits in the Tibetans. Presently, there are two different ventilation phenotypes among high altitude natives as compared with sea level populations at sea level: lifelong sustained high resting ventilation and a moderate HVR among Tibetans in contrast with a slightly elevated resting ventilation and a low HVR among Aymara.

Acclimatization↗
PubMed1997

Quantitative genetic analysis of arterial oxygen saturation in Tibetan highlanders.

This study was designed to test the hypothesis that genetic differences inferred from biological kinship relationships among individuals contribute to individual variation in percentage of oxygen saturation of arterial hemoglobin (SaO2) in a high-altitude native population. SaO2 data were obtained by pulse oximetry from 354 nonpregnant, healthy Tibetan residents of Pen-Dri, two rural agropastoral villages at 3800-4065 m altitude in Lhasa Municipal District, Tibet Autonomous Region, China. Statistical analyses of these data from 46 pedigrees tested the hypothesis of a significant genetic contribution to SaO2 variation. The average SaO2 was 89.4 +/- 0.2%, with a range of 76-97%. Additive genetic effects account for 44% of the interindividual phenotypic variation in SaO2 in the sample. Complex segregation analysis and variance decomposition analysis determined that 21% of the total phenotypic variation could be explained by a major gene influencing SaO2. Homozygotes for the low-SaO2 allele have a mean SaO2 of 83.6%, whereas heterozygotes and homozygotes for the high-SaO2 allele have means of 87.6% and 88.3%, respectively. This confirms findings in another Tibetan sample and extends the known geographic distribution of the major gene. These results suggest the hypothesis that individuals with the dominant allele for higher SaO2 have a selective advantage in their high-altitude hypoxic environment.

Adaptation, Physiological↗
PubMed1994

Major gene for percent of oxygen saturation of arterial hemoglobin in Tibetan highlanders.

This report employs a statistical genetic approach to analyze quantitative oxygen transport variables in a high-altitude (4,850-5,450 m) native Tibetan population and demonstrates the presence of a major gene influencing % O2 saturation of arterial hemoglobin. This result suggests the hypothesis that individuals with the dominant allele for higher % O2 saturation have a selective advantage at high altitude. Studies of the biologically distinctive Himalayan and Andean populations have greatly influenced thinking about ongoing human evolution and adaptation; this is the first statistical evidence for a major gene enhancing oxygen transport in a high-altitude native population.

Adaptation, Physiological↗
PubMed1989

Esthetic orthodontic appliances for the adult.

There is no malocclusion in the adult that cannot be treated as well with esthetic appliances as with the conventional metal brackets. In a study about adult orthodontic patients. Breece and Nieberg found that most people wait until they are adults to start treatment because no one recommended it previously. It is essential that the dental practitioner understand the positive psychological impact of esthetic appliances upon the attitude of the adult and recommend that the adult needing orthodontic treatment enjoy the benefits of these technologic advances in esthetics and comfort.

Adult↗
PubMed1987

Hemoglobin concentration of pastoral nomads permanently resident at 4,850-5,450 meters in Tibet.

This paper presents data on the hemoglobin concentration of a sample of 103 pastoral nomads who are lifelong residents of Phala, at 4,850-5,450 m, on the northern plateau of the Tibet Autonomous Region of the Peoples' Republic of China. This native population resides at the highest altitude of which we are aware and is thus exposed to the most extreme chronic hypoxic stress. However, they do not exhibit the most pronounced physiological adaptations, i.e., hemoglobin concentrations exceeding those found in all other high-altitude populations. Adult male and female mean hemoglobin concentrations of 18.2 and 16.7 gm/dl, respectively, were found. These data, in conjunction with earlier studies of ethnic Tibetans living at 3,400 m, demonstrate a pattern of increasing hemoglobin concentration (erythrocytosis) at increasing altitude of residence in the Himalayas and Tibet. At the same time, however, the hemoglobin concentration is lower than that found among Andean highlanders. These new data raise the possibility of quantitative population differences in hematological adaptation to high altitude hypoxia.

Adolescent↗
PubMed1987

Semen cryopreservation and artificial insemination for Hodgkin's disease.

Seventy-nine men with Hodgkin's disease were treated with chemotherapy protocols at Memorial Sloan-Kettering Cancer Center and had pretreatment semen analysis performed at the area semen bank. The patients were evaluated to determine: the quality of pretreatment semen, the effect of treatment on spermatogenesis, and the success rate of artificial insemination after semen cryopreservation. Pretreatment sperm concentration, fresh motility, fresh progression, postthaw motility and postthaw progression were all significantly decreased in men with Hodgkin's disease compared with normal controls. Posttreatment semen analysis in 44 men showed azoospermia in 80%, sperm concentration, less than or equal to 10 X 10(6)/mL in 11%, and sperm concentration greater than 10 X 10(6)/mL in 9%. Eleven couples attempted artificial insemination using cryopreserved semen, thus far resulting in three pregnancies. Semen cryopreservation and artificial insemination offer a partial solution to posttreatment azoospermia in this population, but further methods are needed to minimize gonadal toxicity without compromising therapy for Hodgkin's disease.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

Age differences in sensory and cognitive function in elderly Nepalese.

This paper describes age differences in sensory and cognitive function in a cross-sectional sample of 117 Nepalese men aged 50 to 88 years living in a traditional agrarian society. The prevalence of impairment of vision, hearing, vibration sensitivity, and cognitive function is progressively higher in successively older age categories in this society as it is in Western industrial societies. This has practical consequences for everyday life. Men with vision impairment are less likely to retain the esteemed social role of head of an extended household. Men with visual and hearing impairment leave their household compounds less frequently, have less frequent social contacts outside their households, and remain inactive a greater proportion of the time. In this technologically simple society without modern medical remedies, vision and hearing impairments are associated with social roles and daily activity patterns that foster economic and political dependence and social isolation.

Aged↗
PubMed1985

The physical fitness of elderly Nepalese farmers residing in rugged mountain and flat terrain.

This paper reports the results of a natural experimental test of the hypothesis that elderly residents of rugged terrains are more physically fit than their counterparts in flat terrains due to the additional lifelong daily exertion occasioned by the inescapable need to walk up and down steep slopes. Cycle ergometer tests of physiological response to work were undertaken by two groups of high caste Hindu male farmers, aged 50 to 79, living in Central Nepal. One comprised an experimental group resident in rugged terrain and the other a control group resident in flat terrain. No differences in heart rate and blood pressure measured at submaximal workloads, at peak effort, or during recovery from exercise were demonstrated. Measurements of physical exertion revealed that few people in either terrain engaged in activity sufficiently strenuous to raise heart rates to a level where training could occur. Despite a rural agricultural lifestyle, these men were not especially physically fit.

Aged↗
PubMed1985

Social structure and intracohort variation in physical fitness among elderly males in a traditional Third World society.

This paper examines the relationship between physical fitness and activity among elderly males in the traditional rural community of Chetbesi, Nepal. It takes advantage of the unique character of the Hindu caste system to implement a quasiexperimental research design that approximates random assignment to high and low activity levels. The members of the Sarki caste have lower heart rates and systolic blood pressure, relative to other castes, at each of three submaximal workloads and during recovery from bicycle ergometer exercise. Direct observation and physiologic monitoring show that the Sarkis engage in more frequent and extended periods of heavy labor. Thus intracohort variation in physical fitness and activity patterns among the Chetbesi elderly is a function of birth into a socially defined group rather than of self-selection. This pattern of differential fitness may typify the process of aging in many stratified traditional and modernizing societies where socially delimited segments of the population perform the bulk of the hard work. Intrapopulation differences aside, comparison of Sarkis and non-Sarkis with other samples reveals that both lie within the reported range of variation. The rural, unmechanized, agricultural lifestyle and mountain environment of Chetbesi do not result in exceptional fitness for residents. The Chetbesi data suggest that the popular notion that aging is less debilitating in traditional agrarian societies located in rugged mountain terrains may be a myth. The demonstration of the influence of social forces on physical fitness suggests that future research might concentrate profitably on identifying social structures that produce high levels of physical fitness.

Aged↗
PubMed1983

Social and economic forces affecting intergenerational relations in extended families in a Third World country: a cautionary tale from South Asia.

This paper questions the implicit assumption derived from modernization theory that elderly persons in the Third World lead secure and satisfying lives because they still live in extended families. Data from elderly Hindus living in Kathmandu, Nepal, are presented and demonstrate that, although these elderly people do continue to live in extended families, social and economic changes have transformed the nature of intergenerational social relations within these families to the detriment of the elderly family members.

Aged↗
PubMed1982

Work, aging and dependency in a Sherpa population in Nepal.

This paper suggests a conceptual framework for the cross-cultural study of dependency in order to encourage and facilitate data-based cross-cultural comparisons. It offers an etic, operational definition encompassing biological, activity and economic components. It also emphasizes that the emic definition is crucial for understanding a situation. The utility of distinguishing several components of an etic definition of dependency and distinguishing etic from emic definition is illustrated using the examples of Sherpas in Helambu, Nepal. From the etic viewpoint, the Sherpas are apparently healthy, economically productive and physically active and therefore lie near the independent end of the dependency continuum. The recent emigration of many young adults has produced a demographic situation where few elderly can achieve their expectation of growing old while sharing their own households with their youngest son and his family. Although family life is valued and most elderly Sherpas have other offspring and other relatives in the village, the majority of elderly Sherpa live alone and express dissatisfaction at doing so. From their standpoint, reliance upon someone other than the youngest son for lodging or food is considered prejoratively and as dependency. Their emic definition of dependency is different from the Western definition and both differ from what we have referred to as etic dependency.

Aged↗
PubMed1982

Migration of fresh and cryopreserved human spermatozoa in polyacrylamide gel.

The ability of freshly collected and frozen human spermatozoa to migrate in round capillary tubes containing specially formulated polyacrylamide gel was investigated, using 33 ejaculates from 27 donors. Each semen sample was divided; one portion was left undiluted, and the other portion was diluted to 50 x 10(6) sperm/ml. Glycerol was used as the cryoprotectant. The percentage of motile sperm cells was determined before and after freezing. Fresh semen contained a higher percentage of motile cells, which migrated farther than those of cryopreserved-thawed semen. Various correlations between the percentage of motile sperm and migration distance ranged from 0.57 to 0.62. There was a low positive correlation of migration distance with sperm cell concentration per milliliter, r = 0.25 to 0.34; and thus adjusting semen samples to a standard sperm concentration improved the accuracy of the test only slightly. The regression coefficient of migration distance on the percentage of motile sperm in fresh semen was 0.65, indicating that for each 10% increase in sperm motility, migration distance is predicted to increase 6.5 mm. Five batches of polyacrylamide gel gave uniform results, and the application of this stable gel to fertility investigations is discussed.

Acrylic Resins↗
PubMed1982

Indirect modernization and the status of the elderly in a rural Third World setting.

Currently the majority of the world's elderly reside in less developed countries and their proportion is increasing. This paper presents evidence that the process of modernization can have a negative impact on the elderly in even the most remote rural Third World settings, even though those settings are not modernized or in the process of modernization in any of the normal uses of that concept. Fieldwork was conducted in Helambu, Nepal on a sample of 37 persons over the age of 50 that included 86% of population aged 60 and over. Despite high levels of activity, health, social and economic status, the elderly were greatly dissatisfied with their situation. The paper demonstrates the manner in which modernization in India has profoundly changed household/family organization in Helambu and produced this situation.

Aged↗