Prevention of HIV infection.
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Acquired Immunodeficiency Syndrome↗
Biomedical subjects
K H Choi
Publications and source records attributed to K H Choi.
Extramarital sex and HIV risk behavior among US adults: results from the National AIDS Behavioral Survey.
Data from the National AIDS Behavioral Survey were used to examine the social distribution of extramarital sex and risk for human immunodeficiency virus (HIV) infection among married individuals in the United States. Of 1686 married respondents living across the United States, 2.2% reported extramarital sex; of 3827 married respondents living in 23 urban areas with large Hispanic or African-American populations, 2.5% reported having sexual partners outside marriage. The data indicate that the correlates of extramarital sex varied by race/ethnicity. Low levels of condom use were found among people reporting extramarital sex (8% to 19% consistent users).
Adolescent↗
Serum erythropoietin levels after living-donor renal allografts.
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Adult↗
A partial blockade of catecholaminergic neurotransmission with 6-hydroxydopamine decreases mRNA level of gonadotropin releasing hormone in the male rat hypothalamus.
Central catecholamines (CA) are known to be involved in the regulation of synthesis and secretion of gonadotropin releasing hormone (GnRH) from the hypothalamus. However, no attempt has been yet made to determine whether CA affects GnRH gene expression. To this end, the effect of 6-hydroxydopamine (6-OHDA), a catecholaminergic neurotoxin, on GnRH mRNA level was examined. Hypothalamic tissues obtained from adult male rats were incubated with medium containing 6-OHDA. To ensure the effect of 6-OHDA on CA depleting action, CA levels in media and in postincubation tissues were determined. Increasing concentrations of 6-OHDA resulted in decrease in norepinephrine (NE) and dopamine (DA) contents in a dose dependent manner. Treatment with 6-OHDA (5 x 10(-4) M produced a time-dependent decrease in NE but not DA, when CA levels in media were determined at 30 min intervals during the incubation period. To determine changes in GnRH mRNA level in response to 6-OHDA treatment in vitro, for 2.5 h total cytoplasmic RNA fractions were isolated from postincubation hypothalamic tissues and used for RNA-blot hybridization with 32P-labeled GnRH riboprobe. A blockade of CA neurotransmission with 6-OHDA (5 x 10(-4) M) significantly reduced GnRH mRNA level by half over its control and internal control (actin mRNA) groups. Northern blot analysis revealed that addition of NE (1 x 10(-6) M) reversed the decreased GnRH mRNA level by 6-OHDA.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Psychosocial predictors of needle sharing among intravenous drug users.
This study examined the relationship between health beliefs and needle sharing in a sample of 226 heroin detoxification clients. Zero-order correlations revealed that needle sharing was positively associated with perceived susceptibility and AIDS anxiety, and negatively associated with self-efficacy and communication skill in negotiating safe needle practices. Logistic regression analysis showed that demographic and situational factors also play a role in needle sharing. White race and injection of drugs in shooting galleries or other public places increase the odds of sharing a "dirty" needle, while that probability decreases sharply as a function of drug users' self-efficacy. This last finding suggests that preventive clinical interventions such as counseling or psychoeducational groups maybe needed to help drug users develop confidence in resisting needle sharing.
Acquired Immunodeficiency Syndrome↗
Comparative study of hepatitis C virus antibody between hemodialysis and continuous ambulatory peritoneal dialysis patients.
We have done cross sectional and prospective studies to determine the prevalence and the clinical significance of antibodies to the hepatitis C virus (Anti-HCV) in 54 hemodialysis (HD) patients and 227 continuous ambulatory peritoneal dialysis (CAPD) patients. Fifteen patients (27.8%) were anti-HCV (+) among the HD group, and twelve patients (5.3%) were anti-HCV (+) among the CAPD group. In the HD group, the positivity of anti-HCV correlated with the duration of HD, but there was no significant correlation with the history of transfusion, the amount of transfusion and abnormal alanine aminotransferase (ALT). At the follow-up study in 164 cases (HD 50 cases, CAPD 114 cases) after 6 months, one of 14 anti-HCV (+) CAPD patients was converted to anti-HCV (-) and two of 35 anti-HCV (-) HD patients were converted to anti-HCV (+). In conclusion, the prevalence of anti-HCV was significantly higher in HD patients compared to CAPD patients, and the positivity for anti-HCV in HD patients correlated with the duration of HD. A regular follow-up of anti-HCV and isolation of anti-HCV (+) HD patients with a separate machine may be needed to prevent the transmission of the hepatitis C virus during hemodialysis.
Adult↗
Studies on IL-2 production and T-cell colony forming unit in patients with chronic renal failure.
To elucidate the nature of altered cellular immunity seen in patients with chronic renal failure, the values of interleukin-2 (IL-2), a kind of lymphokine, and T-cell colony forming units were measured in controls (N = 10), predialysis uremic patients (N = 14), patients undergoing chronic hemodialysis (HD, N = 11) and patients on continuous ambulatory peritoneal dialysis (CAPD, N = 9). Dialytic patients were selected as relatively stable cases receiving dialysis for more than 3 months. The duration of dialysis was 25.5 +/- 5.5 months in HD and 14.7 +/- 3.0 months in CAPD groups. The mean age was 30.3 years in the control, 36.1 years in the predialysis, 32.9 years in the HD and 41.1 years in the CAPD groups; all 4 groups showed male predominance. The serum creatinine concentration of each group was 1.2 +/- 0.1 mg/dl in the control, 14.1 +/- 0.9 mg/dl in predialysis, 13.5 +/- 1.3 mg/dl in HD and 14.7 +/- 0.9 mg/dl in CAPD groups. The level of IL-2 in the predialysis group was markedly lower compared to the control, HD and CAPD groups (as 3.1 +/- 0.8 unit vs. 8.8 +/- 2.2 unit, 11.8 +/- 3.0 unit and 14.9 +/- 3.4 unit, respectively, p < 0.05); the difference between the control and dialytic groups was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
International travel and AIDS risk in South Korea.
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Acquired Immunodeficiency Syndrome↗
Effect of captopril on heavy proteinuria in patients with various glomerular diseases.
The effect of captopril on proteinuria was evaluated in twenty patients with various glomerular diseases excreting heavy proteinuria (> 3.0 g/day). Captopril in a daily dose of 37.5 mg was administered orally three times a day to all patients and they were followed for eight weeks. Twenty-four hour urinary excretion of protein, creatinine, sodium, selective protein index (SPI), and blood chemistry including serum electrolytes were measured every two weeks. Twenty-four hour urinary protein excretion per gram creatinine started to fall within two weeks of captopril administration and became nearly stable after four weeks of therapy (p < 0.05). Mean 24-hour urinary protein excretion decreased significantly from a pretreatment value of 9.0 +/- 6.0 gm/gm of cr. to 4.4 +/- 3.5 gm/gm of cr. after eight weeks of captopril treatment. The serum albumin level increased progressively at six and eight weeks after the captopril treatment period and was significantly higher than the pretreatment value (p < 0.05). The decrease in proteinuria did not coincide with a fall in blood pressure or any changes in creatinine clearance. We conclude that captopril does have a significant antiproteinuric effect in patients excreting heavy proteinuria with various glomerular diseases. However, the long term therapeutic efficacy and any renal protective effect of this drug remain to be proven.
Adult↗
Coping with death anxiety: help-seeking and social support among gay men with various HIV diagnoses.
UNLABELLED: OBJECTIVE, DESIGN AND PARTICIPANTS: We examined sources of help-seeking related to worries or concerns about death and dying and the effects of social support on death anxiety in a longitudinal sample of gay men (n = 52). RESULTS: Friends and primary sexual partners were the most frequent sources sought in dealing with death concerns for all groups of respondents (HIV-negative, HIV-positive asymptomatic, and HIV-positive symptomatic). Men experiencing HIV symptoms were more likely than HIV-negative and asymptomatic men to use formal sources of support (medical, psychological). Although HIV-positive symptomatic men did not differ from HIV-negative men in terms of help-seeking from family sources, they were significantly more likely to seek the help of family members than HIV-positive asymptomatic men. All three HIV groups showed significantly different mean levels of death anxiety, with HIV-negative men reporting the lowest level and HIV-positive symptomatic men the highest. Among HIV-negative men, only mental health sources of support (psychologists and clergy) were significantly related to death anxiety, measured 1 year later (beta = -0.35). These sources of support were also associated with death anxiety among HIV-positive asymptomatic men, but in the opposite direction (beta = 0.26). Contrary to expectations, men experiencing HIV symptoms benefited most from family support (beta = -0.31), although peer (beta = -0.19) and medical (beta = -0.28) support sources were also prominent. CONCLUSIONS: Thus, while earlier research found peers to be the most common and effective source of support among gay men, this study suggests that obtaining support from family may become particularly important as one approaches death. The effectiveness of social support in reducing death anxiety appears to vary over the course of the disease from asymptomatic to symptomatic. HIV-symptomatic men obtain support from a wide range of helpers, including medical and peer supports and family.
Adult↗
Induction of protease La under stress and its effect on intracellular proteolysis in Escherichia coli.
Induction of protease La was found to increase to higher extent in E. coli that had been treated with canavanine for longer period. However, hydrolysis of canavanine-containing proteins occurred rapidly but at nearly an identical rate regardless of the period of canavanine-treatment. Exposure of E. coli to heat also raised the level of protease La but showed little effect on overall rate of proteolysis. These results suggest that induction of protease La under stress occurs as a part of heat shock response but not necessarily for elimination of denatured or abnormal proteins.
ATP-Dependent Proteases↗
Influence of nutritional status on CAPD peritonitis.
To investigate the effect of nutritional status of continuous ambulatory peritoneal dialysis (CAPD) patients on the development of peritonitis, a cross-sectional study of the nutritional status of 79 CAPD patients and a retrospective study on the incidence of peritonitis in these patients were done. The incidences of peritonitis were compared according to the nutritional status of these patients on CAPD. Protein-caloric malnutrition assessed by a score system based on triceps skinfold thickness, mid-arm circumference, serum albumin level and relative body weight was demonstrated in 27 patients (34%) among 79 total CAPD patients. The incidence of peritonitis was significantly higher in poor nutritional status patients, with 1.09 +/- 0.86/patient-year, than that in normal nutritional status patients with 0.64 +/- 0.72/patient-year (p less than 0.05). In patients with the same nutritional status, patients using Dianeal solution had a trend of a lower incidence of peritonitis than those using Peritosol solution. In conclusion, the nutritional status and possibly the type of CAPD solution may influence CAPD peritonitis as risk factors.
Dialysis Solutions↗
Effect of adenine arabinoside and alpha-interferon in patients with HBeAg-positive chronic active hepatitis.
To evaluate and compare the therapeutic efficacy of adenine arabinoside (Ara-A) and alpha-interferon (alpha-INF), 40 patients with biopsy proven chronic active hepatitis B were chosen at random to receive Ara-A (15 mg/Kg, iv, for 10 day) or alpha-INF (3 million unit, sc, every other day for 12 wks) and followed up to 12 months after completion of the therapy. All patients were HBeAg positive. The clinical effects of Ara-A and alpha-INF on seroconversion of HBeAg positive. The clinical effects of Ara-A AND alpha-INF on seroconversion of HBeAg and the levels of serum aminotransferase (ALT) were closely matched and compared with those of the untreated control group (20 cases). Eighteen out of 20 patients received Ara-A, 19 patients received alpha-INF, and 19 out of 20 control cases were evaluated at 12 months after completion of treatment. Seroconversion of HBeAg in the alpha-INF treated group (19 cases) was observed in seven cases (36.8%), showing a higher seroconversion rate as compared to Ara-A-treated (2/18 cases, 11.1%) and to the control patients (1/19 cases, 5.3%). There were no effects of Ara-A on serum ALT levels in the treated patients compared with the untreated control patients. However there was a remarkable drop in serum ALT levels in the INF-treated patients (p less than 0.005, ALT levels at 12 months after treatment; 87.4 +/- 98.8 IU/L) compared to the pretreatment levels (256.7 +/- 175.8 IU/L).(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Hepatitis C infection in hemodialysis units.
We performed an epidemiological study of the hepatitis C infection on 112 patients of 3 urban hemodialysis units using a recently developed anti-HCV recombinant based assay. Eleven patients (9.8%) were positive for anti-HCV. Among them, 8 (72.7%) were positive for anti-HBc, one of whom was HBsAg positive and 6 of whom were also anti-HBs positive. Surprisingly, all of the anti-HCV (+) patients were normal alanine aminotransferase. The mean age of the anti-HCV (+) patients was 50.7 +/- 3.3 (mean +/- SE) and that of the anti-HCV (-) was 47.6 +/- 1.3. The mean duration (month) of hemodialysis of the anti-HCV (+) and anti-HCV (-)groups were 52.7 +/- 7.2 (mean +/- SE) and 60.9 +/- 9.7, respectively. The prevalence of anti-HCV among anti-HBc positive subjects was 9.5% and that among anti-HBc negative subjects was 17.6%. This didn't have any statistical significance according to the criteria of the study (p = 0.308). The prevalence of anti-HCV among the transfusion positive group was 11.0% and that of the transfusion negative group was 7.7%. This data showed the tendency for a higher prevalence of anti-HCV among the transfusion positive group, but this also didn't reach statistical significance (p = 0.424). Of the 40 normal controls, none were anti-HCV positive. The prevalence of HBsAg in our hemodialysis units was 12.5%. This rate was not so much higher than the average population in Korea. The prevalence of anti-HCV and previous hepatitis B virus infection also had no significant relationship.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Alerting drug abusers to overdose threats: the media's role.
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Communication↗
Autonomously replicating episomes contain mdr1 genes in a multidrug-resistant human cell line.
Gene amplification in human tumor cells is frequently mediated by extrachromosomal elements (e.g., double minute chromosomes [DMs]). Recent experiments have shown that DMs can be formed from smaller, submicroscopic circular precursors referred to as episomes (S. M. Carroll, M. L. DeRose, P. Gaudray, C. M. Moore, D. R. Needham-Vandevanter, D. D. Von Hoff and G. M. Wahl, Mol. Biol. 8:1525-1533, 1988). To investigate whether episomes are generally involved as intermediates in gene amplification, we determined whether they mediate the amplification of the mdr1 gene, which when overexpressed engenders cross resistance to multiple lipophilic drugs. A variety of methods including electrophoresis of undigested DNAs in high-voltage gradients, NotI digestion, and production of double-strand breaks by gamma irradiation were used to distinguish between mdr1 sequences amplified on submicroscopic circular molecules and those amplified within DMs or chromosomal DNA. The gamma-irradiation procedure provides a new method for detecting and determining the size of circular molecules from 50 kilobases (kb) to greater than 1,000 kb. These methods revealed that some of the amplified mdr1 genes in vinblastine-resistant KB-V1 cells are contained in supercoiled circular molecules of approximately 600 and approximately 750 kb. Analysis of the replication of these molecules by a Meselson-Stahl density shift experiment demonstrated that they replicate approximately once in a cell cycle. The data lend further support to a model for gene amplification in which DMs are generally formed from smaller, autonomously replicating precursors.
DNA Probes↗
Characterization of outer membrane protein-enriched extracts from Pasteurella multocida isolated from turkeys.
Outer membrane protein (OMP)-enriched extracts of avian strains of Pasteurella multocida were examined by use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Culture medium did not have a significant effect on the OMP profiles of strains of P multocida examined; however, in vivo propagation had an appreciable effect on the OMP profile composition of the reference strain P-1059. Such bacteria, expressed several additional OMP in the 27-kD, 48-kD, 56-kD, 60-kD, 80-kD, and 94-kD molecular mass regions. These OMP were not detected in the electrophorogram of strain P-1059 grown in vitro. The OMP profiles of reference strains of the 16 serotypes of P multocida did not identify any serotype-specific protein markers. Field strains of serotype A:3 had variation in OMP profiles and did not express OMP that all were identical to that expressed by the reference strain P-1059. The live attenuated CU and M9 bacterial vaccine strains expressed strain-specific OMP markers of 48-kD and 45-kD molecular masses, respectively. These strain-specific OMP markers may be used to differentiate these strains from virulent field strains that are of the same serotype and isolated from turkeys that have succumbed to pasteurellosis as a result of vaccine-related reactions or breakdown in immunity.
Animals↗
An altered pattern of cross-resistance in multidrug-resistant human cells results from spontaneous mutations in the mdr1 (P-glycoprotein) gene.
Multidrug resistance in human cells results from increased expression of the mdr1 (P-glycoprotein) gene. Although the same gene is activated in cells selected with different drugs, multidrug-resistant cell lines can be preferentially resistant to their selecting agent. The mdr1 cDNA sequence from vinblastine-selected KB cells, which are uniformly resistant to different lipophilic drugs, was compared with the corresponding sequence from colchicine-selected KB cells preferentially resistant to colchicine. These sequences differ at three positions, resulting in a single amino acid change in P-glycoprotein. These differences result from mutations that occurred during colchicine selection. The appearance of these mutations coincides with the emergence of preferential resistance to colchicine. We have constructed biologically active mdr1 cDNA clones that express either wild-type or mutant P-glycoprotein. Multi-drug-resistant transfectants obtained with the mutant sequence were characterized by increased relative resistance to colchicine compared with transfectants obtained with wild-type sequence. mdr1 mutations are therefore responsible for preferential resistance to colchicine in multidrug-resistant KB cells.
ATP Binding Cassette Transporter, Subfamily B, Mem↗