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Biomedical subjects

S C Hsieh

Publications and source records attributed to S C Hsieh.

At least 37 records · Page 2Linked to original sources
PubMed1995

Abnormal splenic and thymic IL-4 and TNF-alpha expression in MRL-lpr/lpr mice.

The MRL-lpr/lpr and MRL-(++) mice were studied for the expression of cytokines in the spleen, lymph node, thymus, kidney and brain through the reverse transcription-polymerase chain reaction (RT-PCR). The frequencies of IL-4 and TNF-alpha expression in the thymus and spleen were significantly higher in MRL-lpr/lpr mice than in MRL-(++) mice from the age of 17 to 32 weeks. More importantly, IL-4 transcript was demonstrated in the early rather than in the terminal stage of the lupus disease. At the 20th week, MRL-lpr/lpr mice with active disease exhibited higher concentrations of IL-1 alpha, IL-6 and TNF-alpha in serum than MRL-(++) mice. Interestingly, in MRL-lpr/lpr but not MRL-(++) mice, the IL-6 concentration in cultured supernatants of the thymic cells was significantly higher than that of the splenic or lymph node cells. On the other hand, IL-6 and IL-1 beta were expressed in the brain and kidney of MRL-lpr/lpr mice but not of MRL-(++) mice. Cultured MRL-lpr/lpr mesangial cells could also express IL-6 but to a lesser extent. These results suggest that the abnormal splenic and thymic IL-4 and TNF-alpha expression may predispose the development of autoimmune reactions. The expression of IL-1 beta and IL-6 in the brain and kidney may be implicated in the damage of these two organs in MRL-lpr/lpr mice.

Animals↗
PubMed1995

Production of the third component of complement (C3) by peripheral polymorphonuclear neutrophils of the patients with rheumatoid arthritis.

Normal human polymorphonuclear neutrophils (PMN) can spontaneously produce the third component of complement (C3) in in vitro culture as detected by ELISA. This C3-producing capacity of PMN can be augmented by TNF-alpha (20 ng/ml) and bacterial lipopolysaccharide (100 ng/ml), but not by IL-1 beta or IL-8. The C3 production by PMN was found to be temperature dependent and was suppressed by the addition of protein inhibitor. The C3 mRNA in PMN could be detected by reverse transcription assisted polymerase chain reaction (RT-PCR) after TNF-alpha or LPS stimulation for 6 hours. To further understand C3 production by peripheral blood PMN in rheumatoid arthritis (RA), spontaneous and TNF-alpha stimulated production of C3 by peripheral PMN were compared in 15 cases of active RA, 15 inactive RA and 15 normal individuals. We failed to find any significant difference among the three groups. We conclude that PMN plays a negligible role in C3 hypercomplementemia in patients with active RA.

Arthritis, Rheumatoid↗
PubMed1995

Prostaglandin E2 suppresses the expression and release of beta 2-microglobulin from mitogen-activated normal human mononuclear cells.

BACKGROUND: Prostaglandin E2 (PGE2) is a feedback suppressor of immune response. Beta 2-Microglobulin (beta 2M) is part of HLA class I molecule that mediates viral antigen presentation to cytotoxic T lymphocytes as well as graft rejection. It has been known that beta 2M can be synthesized by both stimulated and unstimulated lymphocytes, but it is unknown whether beta 2M can be modulated by PGE2. This investigation aimed to clarify this point. METHODS: Normal human mononuclear cells (MNC) were isolated, stimulated by phytohemagglutinin (PHA), and cultured for 3 days in the presence or absence of PGE2. The culture supernatants were collected and detected for beta 2M concentration by enzyme linked immunosorbent assays (ELISA). The cell pellets were stained indirectly with immunofluorescence for HLA-class I antigen and beta 2M expression on the surface membranes. In addition, the membrane potential of stimulated or unstimulated cells was measured by flow cytometry to evaluate the effect exerted by PGE2. RESULTS: PGE2 at a concentration of more than 1 x 10(-8)M markedly suppressed the expression and release of beta 2M from PHA-stimulated MNC in a dose-dependent manner. Expression of HLA-class I molecule on PHA-stimulated MNC was also suppressed by PGE2. Kinetic study demonstrated that PGE2 began to suppress beta 2M synthesis of PHA-stimulated MNC from the 3rd day of culture. It also inhibited beta 2M release from lymphocytes in mixed lymphocyte reaction. This inhibitory effect was not due to cell death as confirmed by trypan blue exclusion. PGE2 per se exerts negligible effect on membrane potential of MNC but can normalize the depolarized state of the membrane induced by PHA as demonstrated by 3,3'-dihexyloxacarbocyanine iodide stain. CONCLUSIONS: PGE2 down-regulates the production of HLA-class I antigens and beta 2M molecules. This effect is associated with the suppression of cytotoxic T cell function by PGE2 and may be relevant to the underlying mechanism of PGE2 on this population of cells.

Cells, Cultured↗
PubMed1994

Sequential cytogenetic alterations in hamster oral keratinocytes during DMBA-induced oral carcinogenesis.

Using the hamster cheek pouch oral cancer model, we have performed a comprehensive analysis of the cytogenetic changes in hamster oral keratinocytes during 7,12-dimethylbenz[a]anthracene (DMBA)-induced carcinogenesis. Tumour induction in the hamster cheek pouch required repeated application of the carcinogen for 14 weeks. We have found that this hamster oral cancer model to be suitable for cytogenetic studies. Unlike human oral cancers where chromosome breaks have been shown, this is only infrequently observed in DMBA-treated hamster oral keratinocytes. Of importance is the finding that at the beginning of the second week of DMBA treatment, there is a significant increase of karyotypes demonstrating tetraploid or near-tetraploidy. We propose that the significant increase in hamster oral keratinocytes exhibiting tetraploidy be further evaluated as a marker of premalignancy/malignancy.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1994

Reducing HIV risk behavior among injection drug users: effect of methadone maintenance treatment on number of sex partners.

Some studies have found that sex-related HIV risk behavior is less common among drug users in treatment than among users not in treatment; other studies have found no such relationship. However, past studies have not controlled for drug-user background characteristics that might confound the relationship between treatment and risk behavior. Among this sample of injection drug users in Los Angeles, those enrolled in methadone maintenance treatment report fewer past-year sex partners than those not in treatment; among treatment clients, number of past-year partners is negatively related to time in treatment. These findings persist after age and other background characteristics are controlled. Path analyses suggest that treatment may reduce sex-risk behavior by facilitating clients' disengagement from paid sex and raising their perceived self-efficacy for risk reduction.

Adult↗
PubMed1994

The elevation of plasma DNA in patients with systemic lupus erythematosus is attributable to increased DNA release and defective DNA binding of mononuclear cells.

BACKGROUND: Although immunoprecipitable DNA has been found in a subgroup of patients with systemic lupus erythematosus (SLE) exhibiting systemic vasculitis and/or central nervous system involvement, the mechanism for elevated plasma DNA in these patients is poorly understood. METHODS: The plasma DNA concentrations and reactivity of serum and lymphocytes to six species of double-stranded DNA from calf thymus, human placenta, Escherichia coli, Micrococcus lysodeikticus, Clostridium perfringens and poly (dG.dC). poly (dG.dC) were measured in twenty-seven patients with active SLE. To understand the mechanism of increased plasma DNA in SLE, the DNA binding and release of the mononuclear cells were examined. RESULTS: Compared with the controls, the incidence of the presence of plasma DNA was markedly increased in SLE (59.3% in SLE vs. 7.4% in controls) as detected by counterimmunoelectrophoresis. Except for DNA from Clostridium perfringens, the reactivity of lupus sera to various DNA samples was significantly higher than that of the controls. The reactivity of lymphocytes to 6 species of DNA (as defined by 3H-thymidine incorporation of the cells) was also higher in SLE patients. In DNA binding and releasing experiments, patients with SLE were found to have decreased 3H-DNA binding activity (0.169 +/- 0.018 micrograms/2 x 10(6) cells in SLE vs. 0.283 +/- 0.02 micrograms/2 x 10(6) cells in controls, p = 0.001) but to have increased spontaneous release of DNA (1,465 +/- 412 cpm in SLE vs. 630 +/- 179 cpm in controls, p = 0.0173) in mononuclear cells. CONCLUSIONS: The results suggest that some subsets of lymphocytes can be sensitized by different DNA samples in vivo to increase endogenous DNA release from mononuclear cells, which in addition to decreased DNA clearance as has been previously reported, may be responsible for the elevation of plasma DNA in patients with SLE.

Adult↗
PubMed1993

Unrecognized cocaine use among schizophrenic patients.

OBJECTIVE: Unrecognized stimulant use could lead to the misdiagnosis of schizophrenia or the misunderstanding of its course and prognosis. This study was conducted to determine the prevalence of unrecognized stimulant use among patients with a clinical diagnosis of schizophrenia. METHOD: The subjects were 108 schizophrenic patients admitted consecutively to a Veterans Affairs psychiatric hospital. Admitting psychiatrists supplemented routine clinical evaluations with a semistructured interview regarding recent and lifetime use of alcohol, cocaine, amphetamine, marijuana, and opiates. A urine specimen was assayed for the four illicit drugs. RESULTS: Of the 103 patients who provided a urine specimen, 37 (36%) used cocaine during the 6 months before admission, including 31 who used the drug in the week before admission. Because of the poor reliability of negative self-reports of recent cocaine use, clinicians failed to recognize cocaine use in one-third of the patients with a urine toxicology positive for cocaine metabolites. Two other groups of patients were identified; schizophrenic patients without substance abuse (including alcohol) and schizophrenic patients with substance abuse other than stimulants. Both substance-abusing groups were younger than the nonabusing group, but the three groups had similarly high rates of recent psychotic symptoms, homelessness, and unemployment. CONCLUSIONS: Among schizophrenic patients who require hospitalization, clinicians should not rely solely on self-reported stimulant use. Recognition of stimulant use could be improved through routine urine toxicologies for all psychotic patients. The authors suggest that recognition of stimulant use among schizophrenic patients may identify a population with a better prognosis for schizophrenia and different treatment needs.

Adult↗
PubMed1993

Drug-related HIV risk behaviors and cocaine preference among injection drug users in Los Angeles.

Based on a 1988-91 sample of 422 drug-using arrestees in Los Angeles, this study compares the drug-related risk behavior of users whose preferred injection drug is cocaine and users with a preference for heroin or no preference between the two drugs. Cocaine preference is unrelated to the likelihood of needle sharing overall, needle sharing with strangers, needle sharing at shooting galleries, and failure to use bleach as a needle disinfectant. In analyses restricted to users who reported needle sharing, the frequency of sharing is no more closely related to heroin injection frequency than to cocaine injection frequency. These results suggest that local preventive education programs do not need to address distinctive patterns of drug-related risk behavior among injection cocaine users and injection heroin users in Los Angeles.

Adult↗
PubMed1992

Ethnic patterns in drug abuse treatment utilization.

This study describes utilization of drug abuse treatment and related perceptions among African American, Hispanic, and Anglo drug-using arrestees in Los Angeles. The study extends prior research by, first, describing ethnic variation in treatment utilization through analyses that control for nonethnic demographic factors and by, second, exploring the degree to which ethnicity is related to two predisposing factors (attitude toward treatment and perceived need) and two enabling factors (perceived cost and availability). After nonethnic demographic factors and past drug dependence are controlled, African American and Hispanic drug users in Los Angeles are less likely to report having been in drug abuse treatment. Hispanic drug users are more likely than Anglos to say that they have not sought treatment because they do not need it. African American drug users are more likely than Anglos to hold unfavorable views of treatment.

Adult↗
PubMed1992

AIDS knowledge and attitudes among injection drug users: the issue of reliability.

Among injection drug users (IDUs), AIDS-related knowledge and attitudes have not consistently predicted AIDS risk behavior. This may be due in part to the limited reliability of indexes used to measure drug users' AIDS knowledge and attitudes. In addition, the substantive interpretation of findings is confounded if index reliability is lower for particular demographic groups (e.g., ethnic populations and women). This report is based on 8 measures of AIDS-related knowledge and attitudes in a sample of 332 injection drug users in Los Angeles. The reliability of knowledge and attitude indexes for the overall sample is generally acceptable for the purpose of group comparison (average alpha = .60). But reliability is consistently lower for respondents who are Hispanic (average alpha = .49) and respondents with less formal education (alpha = .56). The reliability of 2 measures of sex-related attitudes is lower for female respondents. It is therefore important that the reliability of knowledge and attitude indexes be assessed not just for drug-user samples as a whole, but also within demographic groups of substantive interest.

Acquired Immunodeficiency Syndrome↗
PubMed1991

The effect of increased mastication by daily gum-chewing on salivary gland output and dental plaque acidogenicity.

The effect of increased mastication on plaque metabolism and salivary gland function was determined in 11 human subjects who chewed a sugarless gum for ten minutes of each waking hour for two weeks. Prior to and at the conclusion of the gum-chewing regimen, unstimulated whole saliva and 2% citric-acid-stimulated parotid saliva were collected. Flow rates, pH, and buffer capacity were determined on all saliva samples. In addition, parotid saliva was analyzed for protein concentration and the proteins further studied by SDS-PAGE. The plaque pH response to a 10% sucrose rinse was also measured before and after the regimen. Significant increases were observed in the pH and buffer capacity of unstimulated whole saliva as were similar increases in the flow rate, pH, and buffer capacity of stimulated parotid saliva. Protein concentrations and profiles remained unaffected. In addition, the resting plaque pH and minimum plaque pH reached after a sucrose challenge were both raised significantly, with a significant reduction in the cH area. The results of this study indicate that increased masticatory effort by frequent consumption of sugar-free chewing gum over a prolonged time period resulted in a functional increase in the output of stimulated parotid saliva, as well as in increases in pH and buffer capacity of whole and parotid saliva, which may help to reduce plaque acidogenicity.

Acids↗
PubMed1990

Slowdown in the decline of stroke mortality in the United States, 1978-1986.

The gradual decline in stroke mortality rates observed in the United States since 1900 accelerated markedly around 1973 for whites and around 1968 for blacks. During the next decade stroke mortality rates decreased by almost 50% so that the United States now experiences one of the lowest stroke mortality rates in the world. Beginning in 1979, however the annual rate of decline in stroke mortality began to slow considerably. Comparing the period 1979-1986 with the previous decade, a 57% slowing in the absolute rate of decline (as estimated by the slope of the linear portion of the mortality curve) was observed for white men; the corresponding slowdowns in the rate of decline were 58% for white women, 44% for black men, and 62% for black women. If the decline during the 1980s had continued at the rate observed for the period 1968/73-1978, there would have been 131,000 fewer stroke deaths during the period 1979-1986, 28,000 fewer in 1986 alone. This slowdown in the rate of decline in stroke mortality is occurring while mortality rates for both coronary heart disease and all causes are leveling off. The reasons for this change in the mortality trend remain unknown, and corresponding trends in the treatment and control of hypertension do not provide an entirely satisfactory explanation.

Age Factors↗
PubMed1990

Cell cations and blood pressure in US whites, US blacks, and west African blacks.

Differences in cell cation metabolism have been previously demonstrated between blacks and whites in the US. To investigate a potential racial/genetic basis for these differences we studied red cell sodium content (Nai) and platelet cytosolic calcium (Cai) in a group of US whites (n = 26), US blacks (n = 20) and West African blacks (n = 26) residing in Chicago, IL. Participants in all groups were primarily health professionals. The West Africans had lived in Africa until at least age 21 and subsequently resided in the US for an average of 19 months. Immunological markers were used to estimate European gene admixture among the US blacks. Red cell Nai was significantly lower in US whites (7.72 +/- 2.49 mEq/l cells) compared to both the US blacks and West African blacks (9.98 +/- 2.36 and 10.60 +/- 2.80, respectively; P less than 0.01) and Cai was higher in whites than among US blacks (P less than 0.05). No differences were noted in blood pressure (BP) levels among the three racial groups. A linear correlation existed between Nai and both systolic (SBP) and diastolic (DBP) (r = 0.378 and 0.339, respectively; P less than 0.01), which was strongest among the blacks, particularly the US blacks (SBP vs. Nai, r = 0.716, P less than 0.01). Approximately 20% European gene admixture was present among the US blacks. Based on these findings, it would appear that, compared to US whites, higher levels of RBC Nai are common to black persons native to the US and West Africa.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Leukopenia and hypoxemia induced by hemodialysis].

Patients with uremia usually develop hypoxemia during hemodialysis therapy. It has been thought by most of the investigators that the development of hypoxemia is related to the impropriety of biocompatibility of the dialyzer membranes. Besides, acetate dialysate through metabolism may cause a decrease of respiratory quotient and some amount of CO2 may be lost during hemodialysis. The decrease of CO2 in the blood may induce hypoventilation and therefore develop hypoxemia. A total of 32 patients who received hemodialysis therapy were studied. They were divided into group A and group B. In group A, there were 14 males and 8 females. They were hemodialyzed with cuprophan dialyzer membrane for 22 times totally. In group B, there were 6 males and 4 females. They were hemodialyzed with PMMA dialyzer membrane for 16 times totally. In both groups, acetate dialysate was used. Arterial blood gas analyses were hemodialyzed with PMMA dialyzer membrane for 16 times totally. In both groups, acetate dialysate was used. Arterial blood gas analyses were performed before hemodialysis as the baseline and at 15, 30, 45, 60, 120, 180, 240, and 300 minutes during hemodialysis. White blood cell counts (WBC) were done at the same time when arterial blood gas analyses were performed. The results showed that in group A, a marked decrease of WBC at 15 minutes (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗