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Biomedical subjects

T V Tran

Publications and source records attributed to T V Tran.

At least 19 recordsLinked to original sources
PubMed2001

Membrane macrophage colony-stimulating factor on MADB106 breast cancer cells does not activate cytotoxic macrophages but immunizes rats against breast cancer.

Weakly immunogenic, but highly malignant, rat MADB106 breast cancer cells were retrovirally transduced with the membrane form of macrophage colony-stimulating factor (mM-CSF). The cloned mM-CSF-transfected MADB106 cells physically conjugated with macrophages, but were not killed by the macrophages in 48-h cytotoxicity assays. Macrophages killed the mM-CSF-expressing tumors in the presence of noncytotoxic doses of either taxol or taxol plus cisplatin. This indicated that macrophages bind to the mM-CSF expressed on the tumor cells, but for successful macrophage cytotoxicity to occur against mM-CSF-transduced tumor cells other factors must be present. The mM-CSF-transfected tumor cells were rejected when inoculated subcutaneously into normal rats. Cloned MADB106 tumor cells which expressed high amount of mM-CSF were rejected, while tumor cells that displayed lower levels of mM-CSF grew in 60% of the inoculated rats. The mM-CSF-transfected tumors that grew were smaller and had a greater amount of necrosis, compared to the viral vector tumors. Rats that spontaneously rejected the mM-CSF-transfected MADB106 cells showed rechallenge resistance to unmodified parental MADB106 and R3230Ac breast cancers, but not to the F98 glioma. These observations suggest that breast cancer-specific immunity was induced by the inoculation of mM-CSF-expressing MADB106 tumor cells.

Animals↗
PubMed2001

Health and social service utilization among elderly immigrants from the former Soviet Union.

PURPOSE: To explore factors that affect health and social service use among elderly Russian immigrants from the perspectives of the elders, their adult caregiving children, and the health and social service professionals who serve them. METHODS: A qualitative, case-oriented study design was used and 17 elderly Russian immigrants, 8 adult caregiving children, and 15 health professionals were interviewed in the Boston area in 1998. Perceptions about the patterns of and reasons for Russian elders' health and social service use were summarized through content analysis of the interview data. FINDINGS: Participants across groups perceived extensive service use by elderly Russian immigrants. Life circumstances associated with immigration, cultural norms and beliefs, and structural characteristics of the local Russian immigrant community accounted for service use. CONCLUSIONS: Findings indicate that providing support for depression and loneliness associated with immigration, educating immigrants about the role of primary care providers in the US as well as realistic expectations for American medicine, and managing care to decrease the use of unnecessary services would facilitate appropriate service use among elderly Russian immigrants.

Aged↗
PubMed2000

Evaluation of acoustic beacon characteristics for navigation tasks.

The goal of the present study was to investigate the human factors issues related to acoustic beacons used for auditory navigation. Specific issues addressed were: (1) the effect of various beacon characteristics on human accuracy in turning toward the direction of the acoustic beacon; (2) the difference between real and virtual environments on human accuracy in turning toward the acoustic beacon; and (3) the perceived sound quality of various acoustic beacons. Three experiments were conducted in which acoustic beacons were presented in a background of 80 dBA pink noise. Results of the localization tasks revealed that (a) presentation mode (continuous versus pulsed beacon sound) did not affect the overall localization accuracy or number of front-back confusion errors; and (b) the type of acoustic beacon affected the size of localization error. Results of the sound quality assessment indicated that listeners had definite preferences regarding the type of sound being used as a beacon, with (a) non-speech beacons preferred over speech beacons, (b) a beacon repetition rate of 1.1 rps preferred over either the 0.7 or 2.5 rps rates, and (c) a continuous operation of a beacon preferred over a pulsed operation. Finally, sound quality ratings and localization errors were highly negatively correlated. This finding demonstrates the usefulness and practical values of sound quality judgements for audio display design and evaluation.

Acoustics↗
PubMed2000

Health risks of rural water supply due to lack of proper sanitation in southeast Asian countries.

A comparative study on the effects of lack of sanitation and inappropriate waste handling on water supply was carried out in several Southeast Asian countries that have problems such as inadequate water resources, water supply and sanitation. Though the degree and the cause varied in each country, all the countries investigated had problems arising from contamination of water resources. It was found that there are several sources of water contamination, such as human and animal excreta, solid wastes from nearby houses, graveyards, contaminated river flows, and large-scale landfills for big cities. It was revealed that even when water is clean at the point of production, it could be easily contaminated through broken pipelines or improperly maintained containers. It is still rare to put chlorine into piped water supply and both the inhabitants' and water engineers' understanding of the importance of disinfection should be reemphasised. Although it is urgent to provide piped water supply to those who have only contaminated water sources, such as surface water and dug wells, it is also important to protect these limited water sources from the above-mentioned contamination.

Asia, Southeastern↗
PubMed1998

Pharmacokinetics and pharmacodynamics of cisatracurium after a short infusion in patients under propofol anesthesia.

UNLABELLED: Fourteen patients, ASA physical status I or II, were recruited to assess the pharmacokinetic-pharmacodynamic relationship of cisatracurium under nitrous oxide/sufentanil/propofol anesthesia. The electromyographic response of the abductor digiti minimi muscle was recorded on train-of-four stimulation of the ulnar nerve. A 0.1-mg/kg dose of cisatracurium was given as an infusion over 5 min. Arterial plasma concentrations of cisatracurium and its major metabolites were measured by using high-performance liquid chromatography. A nontraditional two-compartment pharmacokinetic model with elimination from central and peripheral compartments was used. The elimination rate constant from the peripheral compartment was fixed to the in vitro rate of degradation of cisatracurium in human plasma (0.0237 min(-1)). The mean terminal half-life of cisatracurium was 23.9+/-3.3 min, and its total clearance averaged 3.7+/-0.8 mL x min(-1) x kg(-1). Using this model, the volume of distribution at steady state was significantly increased compared with that obtained when central elimination only was assumed (0.118+/-0.027 vs 0.089+/-0.017 L/kg). The effect-plasma equilibration rate constant was 0.054+/-0.013 min(-1). The 50% effective concentration (153+/-33 ng/mL) was 56% higher than that reported in patients anesthetized with volatile anesthetics, which suggests that, compared with inhaled anesthetics, a cisatracurium neuromuscular block is less enhanced by propofol. IMPLICATIONS: The drug concentration-effect relationship of the muscle relaxant cisatracurium has been characterized under balanced and isoflurane anesthesia. Because propofol is now widely used as an IV anesthetic, it is important to characterize the biological fate and the concentration-effect relationship of cisatracurium under propofol anesthesia as well.

Adolescent↗
PubMed1998

Predicting psychological distress among former Soviet immigrants.

This study investigated whether age, gender, marital status, education, employment, length of time in the U.S. and immigration demands (novelty, occupation, language, discrimination, loss, and not feeling at home) were predictors of psychological distress in a sample of 1,647 former Soviet immigrants. Multiple regression analysis indicated that the combined model of demographic and demand of immigration variables was significant. Results indicated that women, older immigrants, those with less than a college education, and those with greater immigration demands related to novelty, language, discrimination, loss, and not feeling at home were most distressed.

Adult↗
PubMed1998

Poverty and impairment in activities of living among elderly Hispanics.

This study employed data from a prior national survey of elderly Hispanics to examine the relationship between poverty and functionally impaired status, i.e., impairment in activities of daily living (IADL). The sample for this study consists of 1,685 Hispanics age 65 and older, representing four ethnic groups: Mexicans, Cubans, Puerto Ricans, and other Hispanics. Ethnic comparisons based on personal characteristics, poverty status and IADL found there were differences among the groups analyzed in terms of marital status, language, religion, age, education, poverty, and IADL. Logistic regression findings revealed that elderly Hispanics who were married, bilingual, and had higher educational achievement were more likely to live above the poverty level than were their counterparts. Findings from an ordinary least squares regression analysis revealed that poor elderly Hispanics had more IADL problems; that men had more IADL problems than women; that IADL problems tended to increase with age; that more educated people had fewer IADL problems; that Cubans had fewer IADL problems than other Hispanics; and that Puerto Ricans had more IADL problems than all other Hispanics. Implications for social work practice are discussed.

Activities of Daily Living↗
PubMed1998

Understanding and responding to the health and mental health needs of Asian refugees.

Asian refugees in the United States have health and mental health needs that are different from those of mainstream Americans and even of recent immigrants. This paper provides a close look at the past experiences and present lives of these refugees, highlights their major problems, and identifies their health and mental health needs. It discusses the reasons why their needs are not being adequately met, and proposes the "what" and "how" of the contributions that social workers can make to addressing those needs.

Acculturation↗
PubMed1998

Development and psychometric evaluation of the Demands of Immigration Scale.

The Demands of Immigration Scale (DI) measures demands associated with immigration, including loss, novelty, occupational adjustment, language accommodation, discrimination, and not feeling at home in the resettlement country. The DI scale was evaluated in a sample of 1,647 immigrants from the former Soviet Union who had resided in the United States from a few months to 20 years. Confirmatory factor analysis supported the proposed factor model. The DI subscales were internally consistent and had good test-retest reliability. Support for concurrent validity was demonstrated by correlations in the expected direction between the DI total and subscale scores and measures of depression and somatization. Support for discriminant validity was demonstrated by mean group differences in some or all of the DI dimensions according to age and years in the United States.

Adult↗
PubMed1997

A sensitive ELISPOT assay to detect low-frequency human T lymphocytes.

We extended the sensitivity of the ELISPOT assay by including an antigen-driven proliferation step prior to a final restimulation with antigen and irradiated antigen presenting cells (APCs). This improved sensitivity made the modified ELISPOT assay better suited to the detection of rare or low frequency T lymphocytes than the standard ELISPOT assay or alternatives such as limiting dilution analysis or in situ hybridization. Use of ELISA-grade plastic or polyvinylidene difluoride (PVDF) plates for the detection of different cytokines improved the signal-to-noise ratio for counting cytokine spots, and use of video computer imaging software improved objective quantitation. Analysis of antigen-reactive peripheral blood mononuclear cells (PBMC) from multiple sclerosis (MS) patients using both the traditional and our modified ELISPOT assay demonstrate a > 10-fold increase in numbers of myelin basic protein (MBP)-responsive T cells detected (an average of less than 1 spot forming cell (SFC) per 2 x 10(5) PBMC with the standard assay compared to 19 SFC per 2 x 10(5) PBMC with the modified assay). In addition, the modified ELISPOT assay could be performed with frozen PBMC, which permitted greater flexibility in sample processing, multiple use of a single sample as an internal standard, and simultaneous analysis of samples collected at different time points. This modified ELISPOT assay has many applications, including analysis of cytokine profiles in rare T cell populations, identification of antigen-responsive individuals as PBMC donors for T lymphocyte cloning or for therapeutic intervention, and assessment of vaccine or therapeutic efficacy as a surrogate clinical marker.

Amino Acid Sequence↗
PubMed1997

Ethnicity, gender and social stress among three groups of elderly Hispanics.

This study examines ethnic and gender differences in social stress among three groups of elderly Hispanics: Mexican Americans (n = 773), Cuban Americans (n = 714), and Puerto Ricans (n = 368). Findings from the crosstabulation analysis between stress and ethnic groups reveal that the elderly Cuban Americans appear to experience less caregiving, family, anxiety, and social dependence stress than their Mexican Americans and Puerto Rican American counterparts. Findings from the crosstabulation analysis between stress and gender reveal that elderly Hispanic women were more likely to experience family, anxiety, social isolation, and social dependence stress. The logistic regression analyses reveal that ethnic differences in family stress, and anxiety and gender differences in caregiving stress and social isolation stress were confounded by differences in sociodemographic and health variables. Further sub-group analyses of ethnic and gender differences provide a more in-depth understanding of social dependency stress and anxiety. Implications for human services and research are discussed.

Journal Article↗
PubMed1997

Psychometric evaluation of the Russian Language version of the Resilience Scale.

The Resilience Scale (RS) was developed by Wagnild and Young (1993) to measure a personality characteristic or coping resource that facilitates adaptation. The RS, however, has not been evaluated with foreign-born populations. Therefore, the purpose of this study was to report the factor structure, internal consistency, and concurrent validity of a Russian language version of the RS in a sample of 450 recent former Soviet immigrants. The 25-item 2-factor solution obtained by Wagnild and Young (1993) was not supported by the Russian data. However, a modified 12-item Russian language version of the RS was, for the most part, reliable and valid: The standardized factor loadings and goodness of fit indices obtained from confirmatory factor analysis were acceptable, the internal consistency of one of the two subscales was very good, and the correlations between scores from the RS subscales and various measures of constructs that are theoretically linked with adaptation were in the expected direction and statistically significant.

Adaptation, Psychological↗
PubMed1993

Psychological traumas and depression in a sample of Vietnamese people in the United States.

This article investigates the relationships among premigration stresses, nightmares, acculturation stresses, personal efficacy, and depression in a sample of 147 adult Vietnamese Americans. The analysis revealed that premigration stresses, nightmares, and acculturation stresses had significant indirect effects on depression. Acculturation stresses diminish personal efficacy, and a weakness of personal efficacy leads to higher depression. Age, gender, marital status, and English language ability also exert differential effects on premigration stresses, nightmares, acculturation stresses, personal efficacy, and depression. Health care professionals, social workers, health care organizations, and social work researchers who work with Vietnamese clients should be more culturally sensitive when planning and implementing services and developing research instruments.

Acculturation↗
PubMed1992

Adjustment among different age and ethnic groups of Indochinese in the United States.

This study examines adjustment among different age and ethnic groups of Indochinese refugees in the United States. The data came from a nationwide probability sample of 3,414 respondents aged 20 or older. Respondents are divided into four age groups (20-29, 30-39, 40-54, and 55 and older). Ordinary least squares regression analysis revealed that education, occupational status, urban/rural location in the country of origin, English language ability, financial problems, gender, age, and length of residence in the U.S. had statistically significant relationships with adjustment in different age and ethnic groups.

Adaptation, Psychological↗
PubMed1991

The behavior of a fast-responding barbituric acid potential-sensitive molecular probe in bovine heart submitochondrial particles.

The barbituric acid probe diBa-C2-(5) responds to the formation of a membrane potential (delta psi) in bovine heart submitochondrial particles (SMP) by a CCCP-reversible, 5-7 nm red shift of the probe absorption spectrum. This shift can be enhanced by the addition of nigericin, an observation that indicates that the probe is specifically sensitive to delta psi. Probe-SMP binding analyses indicate that, relative to the resting state, the ratio of the dye dissociation constant to the maximum number of binding sites decreases by a factor of 30 when delta psi is generated. This observation suggests that the origin of the potential-dependent shift of the probe absorption spectrum is increased occupancy of the SMP membrane by diBa-C2-(5). The time course of the ATP-induced diBa-C2-(5) spectral shift in SMP was complete in nominally 0.2 s and could be described by a single-exponential rate equation. There was no evidence for a slower-phase signal when the data collection time period was increased to 250 s. The apparent first-order rate constants obtained from the single exponential analyses of the barbituric acid ATP-generated signal, however, were a linear function of probe concentration at fixed SMP membrane concentration. The resulting second-order rate constant obtained by linear regression was nominally 1 x 10(7) M (dye)-1 s-1; this value is two to three orders of magnitude higher than that of a number of other well-established probes of delta psi in mitochondrial preparations. Based on the invariance of the kinetics of the oxidation of cytochromes c and c1 by ATP-driven reversed electron transport in the presence and absence of the probe, diBa-C2-(5) does not appear to permeate the SMP membrane on a time scale of milliseconds to several minutes.

Adenosine Triphosphate↗
PubMed1991

Health, stress, psychological resources, and subjective well-being among older blacks.

This study examines the structural relationships among sociodemographic characteristics, health status, stress, psychological resources, and subjective well-being (SWB) among the Black elderly. A structural equation model of SWB was evaluated with data from the 1979-1980 National Survey of Black Americans. The results revealed that poor subjective health status was predictive of lower levels of personal efficacy and SWB. Stressful life events tended to depress subjective assessments of health and had negative effects on self-esteem and SWB. Marital status and age had positive effects on SWB. Chronic health conditions and other demographic variables, however, had indirect effects on SWB.

Adaptation, Psychological↗