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Biomedical subjects

S S Guo

Publications and source records attributed to S S Guo.

At least 55 records · Page 3Linked to original sources

Rheologic determinant changes of erythrocytes in Binswanger's disease.

BACKGROUND: Binswanger's disease (BD) has been associated with severe arteriosclerotic changes in the long perforating arteries and with impaired cerebrovascular responsiveness to hypercapnia. Rheology parameters may become important factors in regulating cerebral blood flow. The purpose of this study was to investigate the changes in rheologic determinants of erythrocytes and to discuss the relation of erythrocytes and white matter lesions in this type of dementia. METHODS: Twenty-eight patients suffering from BD and a control group matched for age, sex and cerebrovascular risk factors were tested for the following hemorheologic variables: erythrocyte deformability, erythrocyte membrane fluidity, erythrocyte aggregation, plasma viscosity and whole blood viscosity. Additionally, red cell membrane metabolic parameters, lipids and individual membrane phospholipids, sialic acid (SA) and malondialdehyde (MDA) contents, and ATPase activities were measured. RESULTS: A significant decrease in erythrocyte deformability, erythrocyte membrane fluidity, membrane phosphatidylethanolamine, membrane phosphatidylcholine, membrane SA and membrane ATPase activities, and a significant increase in membrane cholesterol, cholesterol to total phospholipid ratio, MDA, broad viscosity and erythrocyte aggregation were observed in BD patients when compared with those of the matched control group. CONCLUSIONS: Changes in erythrocyte membrane parameters, especially in phospholipids, can produce serious metabolic disorders and influence the rheologic properties of erythrocytes in patients with BD. These alterations can contribute to a circulatory slowdown and may lead to worsening of the condition of the cerebral white matter in these patients.

Adenosine Triphosphatases↗

[A feasibility study on the highly-efficient electronic fluorescent lamp used as a lighting source for cultivation of higher plant in space].

OBJECTIVE: To testify that the Highly-efficient Electronic Fluorescent Lamp (HEFL) can be used as a sole lighting source for the cultivation of higher plants in space. METHOD: The HEFL was utilized as the lighting source for the culture of three varieties of Luctuca sativa L in the lately-constructed Space Higher Plant Cultivation Ground-based Experimental Facility(SHPCGEF). Other culturing conditions were: temperature 20 +/- 0.2 degrees C, relative humidity (75 +/- 1)%, average photosynthetic active radiation (PAR) 70 micromol m-2 s-1 PPF, average wind velocity 0.45 m/s, photoperiod 24 h light/0 h dark, peat + vermiculite substrate culture, useful growing area 1.2 m2, growing period 28 d, one variety was cultured at every batch. Following plant maturing and being harvested, observations of external morphology of above-ground parts of the plants, measurements and calculations of edible biomass output and photosynthetic efficiency, analysis of nutrient compositions such as proteins, fats, carbohydrates, amino acids, vitamins and elemental compositions of lettuce leaves, and comparisons with formerly-related experiments were made. RESULT: All of the above-mentioned targets met our demands, some of them were superior to the results of other similar experiments. CONCLUSION: The HEFL can completely meet the needs for the growth and development of some higher plants planned to be grown in space, its physical characters basically accord with the demands, so it can be utilized as the only lighting source for higher plant growth in space environmental conditions.

Amino Acids↗

Stature prediction equations for elderly non-Hispanic white, non-Hispanic black, and Mexican-American persons developed from NHANES III data.

OBJECTIVE: To develop new, nationally representative equations to predict stature for racial/ethnic groups of the elderly population in the United States. DESIGN: Anthropometric data for stature, knee height, and sitting height for adults aged 60 years or older were collected from a sample of persons in the third National Health and Nutrition Examination Survey (1988-1994), a national probability sample of the US population. SUBJECTS: A gender- and racial/ethnic-stratified sample of 4,750 persons from the US population (1,369 non-Hispanic white men, 1,472 non-Hispanic white women, 474 non-Hispanic black men, 481 non-Hispanic black women, 497 Mexican-American men, 457 Mexican-American women) aged 60 years or older participated in this study. STATISTICAL ANALYSES: Sampling weights were used to adjust the individual data to account for unequal probabilities of selection, nonresponse, and coverage errors so that all individual data used in these analyses represented national probability estimates. Regression analysis was performed to predict stature in each gender and ethnic group, and the results were cross-validated. RESULTS: Stature prediction models using knee height and age and sitting height and age were evaluated for each gender and racial/ethnic group. The equations with knee height and age were selected on the basis of root mean square error and pure errors in cross-validation and on the accuracy and validity of measures of knee height over sitting height. Results of these regressions, including regression coefficients, standard errors of the coefficients, multiple correlation coefficients, root mean square error, and the standard error for the individual for the final equations, are presented. CONCLUSIONS: New stature prediction equations using knee height and age are presented for non-Hispanic white, non-Hispanic black and Mexican-American elderly persons from current nationally representative data. These equations should be applied when a measure of stature cannot be obtained, for example, for persons with amputations of the leg, or with spinal curvature or who are confined to bed. Predicted stature values are acceptable surrogates in nutritional indexes.

Age Factors↗

Six-compartment body composition model: inter-method comparisons of total body fat measurement.

OBJECTIVE: To compare 16 currently used total body fat methods to a six-compartment criterion model based on in vivo neutron activation analysis. DESIGN: Observational, inter-method comparison study. SUBJECTS: Twenty-three healthy subjects (17 male and 6 female). MEASUREMENTS: Total body water (TBW) was measured by tritium dilution; body volume by underwater weighing (UWW); total body fat and bone mineral by dual-energy X-ray absorptiometry (DXA), total body potassium (TBK) by whole-body 40K counting; total body carbon, nitrogen, calcium, phosphorus, sodium and chlorine by in vivo neutron activation analysis; skinfolds/circumferences by anthropometry (Anth); and resistance by single-frequency bioimpedance analysis (BIA). RESULTS: The average of total body fat mass measurements by the six-compartment neutron activation model was 19.7+/-10.2kg (mean+/-s.d.) and comparable estimates by other methods ranged from 17.4-24.3 kg. Although all 16 methods were highly correlated with the six-compartment criterion model, three groups emerged based on their comparative characteristics (technical error, coefficient of reliability, Bland-Altman analysis) relative to criterion fat estimates, in decreasing order of agreement: 1. multi-compartment model methods of Baumgartner (19.5+/-9.9 kg), Heymsfield (19.6+/-9.9 kg), Selinger (19.7+/-10.2 kg) and Siri-3C (19.6+/-9.9 kg); 2. DXA (20.0+/-10.8 kg), Pace-TBW (18.8+/-10.1 kg), Siri-2C (20.0+/-9.9 kg), and Brozek-UWW (19.4+/-9.2 kg) methods; and 3. Segal-BIA (17.4+/-7.2 kg), Forbes-TBN (21.8+/-10.5 kg), Durnin-Anth (22.1+/-9.5 kg), Forbes-TBK (22.9+/-11.9 kg), and Steinkamp-Anth (24.3+/-9.5 kg) methods. CONCLUSION: Relative to criterion fat estimates, body composition methods can be organized into three groups based on inter-method comparisons including technical error, coefficient of reliability and Bland-Altman analysis. These initial groupings may prove useful in establishing the clinical and research role of the many available fat estimation methods.

Absorptiometry, Photon↗

Total-body and regional bone mineral content and areal bone mineral density in children aged 8-18 y: the Fels Longitudinal Study.

BACKGROUND: Techniques for cross-calibration of bone mineral content (BMC) and bone mineral density (BMD) between manufacturers of dual-energy X-ray absorptiometry (DXA) instruments are currently inadequate for total body measurements. Therefore, manufacturer-specific data for BMC and BMD in children are needed. OBJECTIVE: We provided age- and sex-specific means and SDs for total-body and regional BMC and areal BMD in 8-18-y-old white children. DESIGN: BMC and BMD of the head, arms, legs, pelvis, spine, and total body were determined by DXA. Data include 465 annual measurements from 148 healthy children with body weights between 30 and 100 kg and statures <190 cm. RESULTS: There were significant sex differences in BMC at ages 15-18 y for the total body and legs, at ages 12 and 15-18 y for arms and pelvis, at ages 11-13 and 16-18 y for the spine, and at ages 10-11 y for the head. There were significant sex differences in BMD at ages 16-18 y for total body, arms, and legs; at ages 12-13 and 16-18 y for the pelvis; at ages 12-14 and 18 y for the spine; and at ages 13-18 y for the head. CONCLUSIONS: Data presented in this investigation can be used to compare the BMC and BMD of 8-18-y-old white children (with statures <190 cm and body weights between 30 and 100 kg) using DXA.

Absorptiometry, Photon↗

Effects of self-perceived hair loss in a community sample of men.

BACKGROUND: Few studies have quantified the psychosocial effects of hair loss using standardized instruments in men not seeking treatment for hair loss. OBJECTIVE: Examine self-perception of hair loss and its effects on men from the community. METHODS: Men 18-50 years of age recruited without regard to hair loss, from households near Dayton, Ohio, completed a questionnaire assessing self-perception of hair loss, satisfaction with hair appearance, hair-loss-specific effects and general health status. RESULTS: Men with greater hair loss had more bother, concern about getting older, perceived noticeability to others and greater dissatisfaction with their hair appearance than men with less hair loss. These effects decreased with age for men with hair loss, but regardless of age, perceived noticeability of hair loss increased monotonically with degree of hair loss. CONCLUSIONS: Men with greater hair loss report more negative effects due to their hair loss across all age groups, but the effects were more pronounced in younger men.

Adolescent↗

Serial changes in body composition throughout adulthood and their relationships to changes in lipid and lipoprotein levels. The Fels Longitudinal Study.

Few studies have examined the relationships between measures of body composition and lipid and lipoprotein levels in long-term serial data from individuals unselected for cardiovascular disease- or obesity-related variables, and none have considered such extensive serial data as used in the current study. The aim was to examine in such individuals the associations between annual changes in lipid and lipoprotein levels and concurrent changes in total body fat, fat-free mass, percent body fat, and body mass index. Serial data from 1304 examinations of 423 adult white participants in the Fels Longitudinal Study were analyzed sex-specifically in 2 age groups, 18 through 44 years and 45 to 65 years. A regressive analytic approach utilized the long-term (4 to 20 years) serial data of individuals. Annual changes in adiposity, independent of levels of lean tissue changes, before and after age 45 for men and women were significantly correlated with corresponding annual changes in cholesterol and low density lipoprotein cholesterol. In men before age 45, changes in triglycerides and high density lipoprotein cholesterol were also significantly associated with changes in adiposity, with the relationship remaining after age 45 in high density lipoprotein cholesterol. Increases in adiposity in individuals are associated with changes in lipid and lipoprotein levels in the direction of increased risk for cardiovascular disease. Adult levels of total cholesterol and low density lipoprotein cholesterol across age and sex and high density lipoprotein cholesterol in men are responsive to changes in adiposity, independent of initial adiposity or lipid and lipoprotein levels.

Adolescent↗

Growth in weight, recumbent length, and head circumference for preterm low-birthweight infants during the first three years of life using gestation-adjusted ages.

Data from 867 preterm low-birthweight participants in the Infant Health and Development Program (IHDP) were used to develop reference data for growth status at an age and for increments from term to 36 month gestation-adjusted age (GAA). Weight, length and head circumference were recorded at 4 month intervals in the first year and at 6 month intervals in the second and third years. Selected percentiles for values at an age (status values) and increments for age intervals are presented in graphs separately for VLBW infants (< or = 1500 g at birth) and for LBW infants (1501-2500 g at birth). Percentiles of weight increments are presented beginning shortly before term for 1 month intervals to 6 month GAA, for 2 month intervals to 12 month GAA, and for 3-month intervals to 36 month GAA. Percentiles for length and head circumference increments are presented from term to 6 months for 2-month intervals, and to 36 month GAA for 3 month intervals. Among LBW infants, boys, had larger status and increment values than girls (P < 0.05), but there were no significant sex-associated differences in VLBW infants for status or increments. The mean status values and increments in weight and head circumference of the LBW infants were larger than those of VLBW infants, but the differences in length were not significant.

Aging↗

Reference data for head circumference-for-length in preterm low-birth-weight infants.

OBJECTIVE: To provide reference data for head circumference-for-length in preterm low-birth-weight infants that are independent of age, but extend for the ranges of head circumference (34-49 cm) and length (52.0-102.9 cm) values found from birth to 36 months of gestation-adjusted age. DESIGN: Measurements were made at 9 ages in 867 preterm infants in the Infant Health Development Program, a randomized clinical trial that included various ethnic groups at 8 sites. At birth, two thirds of the infants weighed less than 2000 g, and one third weighed between 2000 and 2500 g. Measurements were taken at birth, at 40 weeks of postconceptional age, and at 4, 8, 12, 18, 24, 30, and 36 months of gestation-adjusted age. A model fitted to the serial data for each infant was used to estimate head circumference and length from 36 weeks after conception to 36 months of gestation-adjusted age. RESULTS: Tables and charts of means and SDs and selected percentiles for each sex were made. These tables and charts are for very low (< or = 1500 g) and low-birth-weight (1501-2500 g) infants by 3-cm intervals of length. CONCLUSION: These tables and charts should assist clinicians in evaluating and monitoring head circumference in preterm low-birth-weight infants by taking body length into account.

Body Height↗

Age- and maturity-related changes in body composition during adolescence into adulthood: the Fels Longitudinal Study.

OBJECTIVES: To examine patterns of change in total body fat (TBF), percent body fat (%BF), and fat-free mass (FFM), from 8-20 y of age and the effect of rate of skeletal maturation. To determine the degree of tracking of body composition for individuals from childhood into adulthood. RESEARCH DESIGN: Annual serial data for TBF, %BF and FFM from underwater weighing using a multicomponent body composition model were collected from 130 Caucasian males and 114 Caucasian females between 1976 and 1996. Rate of maturation was defined as FELS skeletal age (SA) less chronological age (CA). Random effects models were used to evaluate general patterns of change and tracking of individual serial data over the 12 y age range. RESULTS: Changes in TBF followed a quadratic model for males and for females with declining rates of change. Changes for %BF followed a cubic model for males and females. General patterns of change for FFM followed a cubic model for males and a quadratic model for females. TBF for males and females increased with age, but the rates of change declined with age. %BF for females increased from age 8-20 y. For males, %BF increased with age, but the positive rates of change declined and became a negative when aged about 13 y and reached a minimum at about the age of 15 y. The rate of change for %BF increased thereafter. FFM for males and females increased with age, but the rates of change decreased with age. The extent of tracking is inversely related to the length of the time interval. At the same age, rapidly-maturing children have significantly larger amounts of TBF, %BF and FFM then slow-maturing children. Tracking in body composition for individuals persisted from childhood to adulthood. CONCLUSIONS: (1) There are gender-associated differences in these patterns of change for %BF and FFM but not for TBF; (2) TBF, %BF and FFM increased with increased rates of maturation; (3) significant tracking in body composition for individuals persists from childhood to adulthood.

Adolescent↗

Opportunities and difficulties in long-term studies of growth.

Overviews are presented of the University of Melbourne Child Growth Study and of the Fels Longitudinal Study; each of these studies had a major focus on the growth and maturation of children. Planning, study design, logistics and staffing varied between these studies, but each led to exciting research opportunities that can exist only when longitudinal data are available. There are important differences between these studies in the types of participants, ages at examinations, the variables measured, some topics of central concern, and in funding. In each study, research productivity was low in the early years, the retention of participants was a major concern, and it was necessary to maintain a balance between data collection, data management, and data analysis. More such studies are needed that focus on particular population groups and topic areas and that utilize the lessons of the past to maximize the chances of future success.

Adolescent↗

The effects of T cell subpopulations and recombinant interleukin (IL)-2 on peripheral B cell function in patients with myasthenia gravis.

Myasthenia gravis is an autoimmune disease mediated by antibodies to acetylcholine receptors (AChR) of skeletal muscle. The production of anti-AChR antibodies has been shown to be T cell dependent. To elucidate the mechanism(s) of anti-AChR antibody production in myasthenic patients, we studied the effects of regulatory T cells and/or IL-2 on the differentiation of AChR-primed B cells, with use of AChR stimulation for the induction of anti-AChR antibodies in vitro. Our data suggest that CD8+ T cells possess some complicated functions. CD8+ T cells could not only provide help for B cells to secrete anti-AChR antibody, but also possibly inhibit response of CD4+ T cells or kill B cells, then repress anti-AChR antibody production in MG patients. There might be some defect either in the number or function of CD8+ T cell in MG patients. Exogenous IL-2 could completely restore the suppression activity of CD8+ T cells in anti-AChR antibody production in vitro.

Adult↗

[Effect of xianzhen tablet on Na(+)-K(+)-ATPase, Ca(2+)-Mg(2+)-ATPase, of red blood cell membrane in patients with non-insulin dependent diabetes mellitus].

OBJECTIVE: To assess the effect of Xianzhen tablet in treating non-insulin dependent diabetes mellitus (NIDDM). METHODS: Seventy-two cases of NIDDM patients with deficiency of both Qi and Yin, deficiency of the Kidney and blood stasis were selected, and the effects of treatment on Na(+)-K(+)-ATPase, Ca(2+)-Mg(2+)-ATPase, whole blood viscosity, blood sugar and clinical symptoms were observed. RESULTS: After treatment, the treated group showed increased activities that were statistically significant of Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase (P < 0.01, P < 0.02). The whole blood viscosity and symptoms showed improvement to an extent and the total effective rate of blood sugar lowering were as follows: fasting blood glucose (FBG) 77.8%, 2hr. postprandial plasma blood glucose (2hr. postprandial PBG)69.4%. Whereas, the placebo group showed no marked improvement in either whole blood viscosity or symptoms and the total effective rate of blood sugar lowering were FBG 41.7%, 2hr. postprandial PBG 38.9%. CONCLUSION: Xianzhen tablet is effective in improving the activities of Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase, as well as the whole blood viscosity, blood sugar lowering and in improving clinical symptoms, it could treat effectively NIDDM patients with deficiency of both Qi and Yin, deficiency of the Kidney and blood stasis.

Adult↗

Weight-for-length reference data for preterm, low-birth-weight infants.

OBJECTIVE: To provide weight-for-length reference data for preterm, very-low-birth-weight and low-birth-weight infants. DESIGN: Data from 867 infants (428 boys and 439 girls) in the Infant Health and Development Program, who each were preterm and who had a low birth weight, were used to develop weight-for-length reference data. The Infant Health and Development Program is a national, randomized, clinical trial that included various ethnic groups at 8 sites. At each site, sampling ensured that two thirds of the infants in the study weighed 2000 g or less and that one third of the infants weighed from 2001 to 2500 g at birth. Infants were examined at birth, at 40 weeks' postconception, and at 4, 8, 12, 18, 24, 30, and 36 months' gestation-adjusted age. Gestation-adjusted age was used instead of chronological age from birth to correct for the degree of prematurity. RESULTS: Weight-for-length percentiles are given for lengths at 3-cm intervals ranging from 48 to 100 cm. These percentiles are sex specific and are for a very-low-birth-weight group (< or = 1500 g) and a low-birth-weight group (1501-2500 g). CONCLUSIONS: These data should assist screening for deviations from normal growth and may aid in the early detection of failure to thrive and excessive weight gain in infancy.

Anthropometry↗