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Biomedical subjects

J Liang

Publications and source records attributed to J Liang.

At least 289 records · Page 16Linked to original sources
PubMed1991

The structure of self-reported physical health among the aged in the United States and Japan.

This article attempts to extend the generalizability of a three-dimensional model of self-reported physical health among the aged to a nonwestern culture. Consisting of three interrelated dimensions, chronic illness, functional status, and self-rated health, this model was empirically evaluated by using national data on the aged gathered in the United States and Japan. The three-dimensional specification was found to apply equally well to U.S. and Japanese elderly. In addition to examining the internal structure of this three-dimensional model, the study assessed the model's relationships with a set of selected exogenous variables including age, sex, marital status, and education. The relationships between the selected exogenous variables and physical health dimensions are largely similar in both countries. However, clear differences appeared in at least three instances.

Activities of Daily Living↗
PubMed1991

[Malondialdehyde-modified-low density lipoprotein in diabetes mellitus].

Malondialdehyde-modified-low density lipoprotein (MDA-LDL), lipid peroxide (LPO), lipid and fasting blood glucose (FBG) were studied in 42 diabetic patients and 20 age-matched controls. The results revealed that both MDA-LDL per L serum and MDA-LDL per mol LDL-C of diabetics were higher than those of controls. MDA-LDL/L tended to be much higher in diabetic patients with vascular disease and hyperlipidemia. There was a positive correlation between MDA-LDL/L and LPO, LDL-C, TC, respectively.

Adult↗
PubMed1991

[The effect of gemfibrozil on serum apo C II and C III in diabetic hyperlipidemia].

The effects of gemfibrozil on apolipoproteins C II and C III (apo C II, C III) were observed in 20 NIDDM hyperlipidemic patients. All of the patients continued their anti-diabetic treatment, gemfibrozil 900 mg/day for 4 weeks. The results revealed no significant change in fasting plasma glucose (FPG) and HbA1 before and after the study. But after the treatment with gemfibrozil, the following parameters changed significantly: total cholesterol (TC) decreased by 18.64% (P less than 0.01), total triglyceride (TG) decreased by 65.05% (P less than 0.001), VLDL-C decreased by 63.19% (P less than 0.001), HDL-C increased by 44.23% (P less than 0.001), apo C III decreased by 31.38% (P less than 0.02), and the ratio of apo C III/C II reduced by 35.49% (P less than 0.01). These findings suggest that gemfibrozil has excellent effect on decreasing apo C III and the ratio of apo C III/C II, thus facilitates the metabolism of chylomicron and decreases TG level in hyperlipidemic diabetic patients.

Aged↗
PubMed1990

Citrate substitutes for homocitrate in nitrogenase of a nifV mutant of Klebsiella pneumoniae.

An organic acid extracted from purified dinitrogenase isolated from a nifV mutant of Klebsiella pneumoniae has been identified as citric acid. H2 evolution by the citrate-containing dinitrogenase is partially inhibited by CO, and by some substrates for nitrogenase. The response of maximum velocities to changes in pH for both the wild-type and the NifV- dinitrogenase was compared. No substantial differences between the enzymes were observed, but there are minor differences. Both enzymes are stable in the pH range 4.8-10, but the enzyme activities dropped dramatically below pH 6.2.

Citrates↗
PubMed1990

Peer influence in adolescent cigarette smoking.

A structural model relating actual and perceived peer smoking to perceived peer pressure and to adolescent cigarette smoking was developed and replicated in two independent subsamples of the data. Data was gathered from 2334 suburban adolescents in grades 8 and 11 in a large metropolitan area. Four dimensions of peer pressure were discovered and were found to relate differentially to adolescent smoking. The major findings were that pathways representing modeling and normative pressure to smoke had roughly equal impact on adolescent smoking. Direct pressure to smoke cigarettes did not have a significant path to adolescent smoking. Adolescents reported low levels of both normative and direct pressure to smoke cigarettes. Smoking adolescents appear to see the peer group, not as encouraging them to smoke, but as not providing any discouragement for smoking. Finally, adolescents who were experimenting with smoking or were smokers overestimated the amount of smoking by their best friends.

Adolescent↗
PubMed1990

Personality, social support, and psychological distress in later life.

A conceptual model was developed to address 2 issues that have received relatively little attention in the social support literature. First, an attempt was made to assess the interrelationships among 3 types or dimensions of supportive social relations. In addition, the impact of selected psychological and social factors on social support use was examined. Findings from a nationwide survey of older adults in the United Kingdom suggest that social contact tends to increase the amount of received support, and received support in turn tends to bolster perceptions of support availability in the future (i.e., anticipated support). With regard to the second issue, social roles (especially marital status) and social extraversion emerged as potentially important correlates of social support use in later life.

Adaptation, Psychological↗
PubMed1990

Appropriateness of composites in structural equation models.

The appropriateness of using composites instead of multiple indicators in a structural model of physical health was evaluated. Liang's (1986) specification of self-reported physical health is a relatively complex multiple indicators model which may not be practical in actual application. To simplify this formulation, a two-stage strategy was used. First, reliability was estimated for each composite to fix the measurement error variance and the regression of the composite on the latent variable. Second, the model was reestimated by constraining these parameters. Regression analyses were undertaken to assess the impact of using composites instead of multiple indicators. Parameter estimates for causal linkages and residual error variances based on multiple indicators approach were closely reproduced by using composites, thus providing justification for the proposed strategy.

Activities of Daily Living↗
PubMed1990

[Study on the production, identification of serogroup-specific monoclonal antibodies against leptospires of Australis serogroup and detection of its antigen].

Spleen cells of BALB/c mice immunized with whole Leptospira interrogans serogroup Australis serovar australis strain 620 were fused with myeloma cells line SP2/0. Specificities of four McAbs determined by MAT. 2E1 McAb (IgG3) reacted with 11 serovars, of the Australis serogroup, but did not react with 22 representative serovars of L. interrogans in 20 serogroups, L. biflexa strain patoc I and Leptonema illini strain 3055. 2E1 McAb showed serogroup specificity for Australis by agglutination and the other 3 McAbs showed partial serogroup specificity. We compared the outer envelope (OE) protein profiles of serovar australis strain 620 with those of two pathogenic L. interrogans serovar lai strain 601 and serovar hebdomadis strain 156 by SDS-PAGE. 63kd protein profile was only found in the OE of strain 620, and the quantity of 42kd protein of strain 620 was greater than that of strain 601 and 156. The immunoblotting revealed that 2E1 McAb reacted with a 34kd band in the OE preparation of serovar australis strain 620, but did not react with that of other two L. interrogans. 2E1 McAb also did not react with OE of non-pathogenic leptospires. It was suggested that 34kd protein might contain the antigenic determinants which were shared by leptospires of Australis serogroup.

Animals↗
PubMed1990

Clinical application of microcomputer to visual function examination.

Microcomputer technique is put into use in ophthalmological clinical visual function examination. In visual EOG, ENG, visual tracking, contrast sensitivity and VEP examination, objectifying and standardization of experiment and data analysis are achieved by computer technique. In addition, a lot of manpower and time is saved, test results are obtained faster and more accurately. The basic rational of computerization in clinical visual function examination is presented.

Adult↗
PubMed1990

Analytical approaches to detection and characterization of disease-linked chromosome aberrations.

Flow karyotyping and FISH with chromosome specific or disease-locus-specific probes are powerful adjuncts to conventional cytogenetic analysis. Flow karyotyping is well suited to quantitative analysis of DNA content changes that occur during structural rearrangement. FISH with probes for repeated sequences allows ready detection of aneuploidy in interphase cells. FISH with whole chromosome composite probes to metaphase spreads facilitates detection of subtle structural changes and allows detection of structural aberrations that occur at frequencies as low as 10(-3). FISH with locus-specific probes facilitates diagnosis of specific genetic diseases, allows phenotype-genotype correlation on a cell-by-cell basis and may be developed into a sensitive method for detection of residual disease.

Chromosome Aberrations↗
PubMed1990

[Preliminary report of efficacy of diabetic polyneuropathy treated with large dose inositol].

Ten diabetics with polyneuropathy were studied by taking 6g inositol tablets (each tablet contains 0.25g inositol) per day for three months. The results showed that large dose inositol could reduce the severity of clinical symptoms, but there was no improvement of the nerve conduction velocity. The possible mechanism of these changes was discussed. According to the clinical observation of the therapeutic effect in those 10 cases, the authors would deem that large dose inositol is an effective drug for diabetic polyneuropathy, and it is worthy of further clinical trial, but other sensitive indicators should be used to evaluate the efficacy of this drug.

Adult↗
PubMed1989

Binding of sulfonamide and acetamide to the active-site Zn2+ in carbonic anhydrase: a theoretical study.

Self-consistent field molecular orbital (SCF MO) calculations at both 4-31G and STO-3G levels have been used to examine the binding conformations of sulfonamide and acetamide compounds to the active site of carbonic anhydrase. The results are as follows: (1) sulfonamide binds to the Zn2+ ion in its deprotonated form through the sulfonamide nitrogen to the fourth coordination site of the metal ion; (2) acetamide as neutral species binds to the basic form of the enzyme through the carbonyl oxygen to the fifth coordination site of the metal ion; and (3) the acetamidate ion binds to the acid form of the enzyme through the amide nitrogen to form a tetracoordinated metal complex with three histidine ligands. Analysis of the effects of individual active-site residues on the binding conformations of these inhibitors suggests that metal alone favors bidentate coordination of sulfonamidate and acetamidate complexes and that electron donation from three histidine ligands to the metal ion determines the formation of a tetracoordinated metal complex, which is further stabilized by the presence of Thr 199, as it receives one hydrogen bond from the sulfonamide NH- or from the acetamide NH- and donates a backbone NH hydrogen bond to a sulfonamide oxygen. The calculated binding conformation of sulfonamide and the hydrogen-bonding interactions between sulfonamide and the enzyme are consistent with the X-ray diffraction study of the AMSulf-HCA II complex. However, no X-ray structures are available for amide-HCA II complexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetamides↗
PubMed1989

Satisfaction with social support and depressive symptoms: a panel analysis.

The literature suggests that persons who are dissatisfied with the amount of social support that has been provided to them may subsequently suffer from psychological disorder. At the same time, there is evidence that individuals who initially suffer from emotional disorder may consequently be less satisfied with their social support systems than may persons who enjoy better mental health. The purpose of this study was to test these competing hypotheses with panel data from a community survey of older adults. The findings indicate that changes in satisfaction with support tend to precede changes in depressive symptoms. A number of issues in the analysis of longitudinal data are discussed.

Adaptation, Psychological↗
PubMed1989

Generational differences in the structure of the CES-D scale in Mexican Americans.

This study examines differences in the structure of the Center for Epidemiologic Studies Depression (CES-D) scale across three generations of Mexican Americans. The covariance structure of the items was viewed as a function of several parameter matrices. Factorial invariance was evaluated by testing a series of hypotheses involving equivalence constraints on one or more parameter matrices. The findings revealed that the proposed 12-item model fits the data within each of the three generations adequately. Although no generational differences in factor loadings were revealed, structural variations of the CES-D in measurement error variances were found. Measurement error variances associated with certain items in the older generation are significantly greater than those in the middle-aged and young generations. In addition, socioeconomic characteristics, acculturation, and health status fail to explain the observed differences in the structure of the CES-D among the three generations.

Adult↗
PubMed1989

Mortality decline and Chinese family structure: implications for old age support.

This study examined the effect of mortality change on the probabilities of survival for various family members and parent/child joint life expectation in Chinese mainland and Taiwan during the past 60 years. Major increases in life expectancy have led to the doubling of the average number of person years of an individual's life spent as a grandparent during that time. In a sense, the family burden of old age support is twice as much as before. It is concluded that the role of family in providing old age support needs to be complemented and reinforced by public programs.

Adult↗
PubMed1989

Dimensions of the OARS mental health measures.

A measurement model of mental health for the Older Americans Resources and Services (OARS) questionnaire is described. Using confirmatory factor analysis on noninstitutionalized elderly from Cleveland (N = 1834) and Virginia (N = 2146), the 21 OARS mental health items were fit to a 15-item model. In addition to the second-order construct of mental health, there were four first-order dimensions: life satisfaction, psychosomatic symptomatology, alienation, and cognitive deficit. Analyses were further replicated by splitting both samples in half. The model fit well and compared favorably to other alternative specifications. In addition to this analysis of internal structure, the model was also examined in relation to several exogenous factors including age, sex, race, education, and physical health. While the model again fit well, a model with cognitive deficit separate from the other factors seemed more reasonable.

Aged↗
PubMed1989

N2O reduction and HD formation by nitrogenase from a nifV mutant of Klebsiella pneumoniae.

Dinitrogenase from a nifV mutant of Klebsiella pneumoniae contains an altered form of iron-molybdenum cofactor (FeMoco) that lacks a biologically active homocitric acid molecule. Change in the composition of FeMoco led to substantial variation in the kinetics of nitrogenase action. The KmS of the mutant enzyme for N2 and N2O were 0.244 and 0.175 atm (24,714 and 17,726 kPa), respectively. The km for N2 was higher and the Km for N2O was lower than that for the wild-type enzyme. The mutant enzyme was ineffective in N2 fixation, in N2O reduction, and in HD formation, as indicated by the low Vmax of these reactions with saturating levels of substrate and under conditions of saturating electron flux. These observations provide further support for the concept that N2, N2O, and D2 interact with the same form of dinitrogenase. H2 evolution by the mutant enzyme is only partially inhibited by CO. Observation that different numbers of electrons are stored in CO-inhibited than in noninhibited dinitrogenase before H2 is released suggests that the mutant enzyme has more sites responsible for H2 evolution than the wild-type enzyme, whose H2 evolution is not inhibited by CO.

Ammonia↗