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Biomedical subjects

S Hwang

Publications and source records attributed to S Hwang.

At least 37 records · Page 2Linked to original sources
PubMed2004

Use of microwave pretreatment for enhanced anaerobiosis of secondary sludge.

This work elucidates the effects of pretreatment of secondary sludge by microwave irradiation on anaerobic digestion. The soluble chemical oxygen demand (COD) concentration increased up to 22% as microwave irradiation time increased, which indicated the sludge particles disintegrated. Three identical automated bioreactors with working volume of 5 l were used as anaerobic digesters at mesophilic temperature (35 degrees C). The reactors were separately fed with sludge with microwave pretreated- and control- sludge at different hydraulic retention times (HRT). The volatile solid (VS) reduction in the control operation was approximately 23.2 +/- 1.3%, while it was 25.7 +/- 0.8% for the reactors with the pretreated sludge. The average biogas production rate with the pretreated sludge at 8, 10, 12, and 15 days HRTs was 240 +/- 11, 183 +/- 9, 147 +/- 8, and 117 +/- 7 ml/l/d respectively, while those with the control sludge were 134 +/- 12 and 94 +/- 7 ml/l/d at 10 and 15 days HRTs. Maximum rates of COD removal and methane production with the pretreated sludge were 64% and 79% higher than those of the control system, respectively.

Anaerobiosis↗
PubMed2003

Statistical implications of pyrene and phenanthrene sorptive phenomena: effects of sorbent and solute properties.

A 3 x 2 factorial experiment in a generalized randomly complete block was conducted to assess the effects of soil type, soil preparation, and solute concentration on the sorptive behavior of pyrene (PYR) and phenanthrene (PHE). Three bulk soils were treated to remove the soil organic matter (SOM) or clay fractions, then spiked with an initial PYR/PHE concentration of either 3 or 15 mg/L. On average, 98.3% PYR and 91.3% PHE were sorbed to the bulk soils in 24 h, with 4.96 mg PYR kg(-1) soil and 22.48 mg PHE kg(-1) soil desorbed after three successive 24-h desorption steps. Both clay minerals and SOM greatly contributed to the sorptive behavior. For example, an average 95.1% and 96.1% of the initial PYR sorbed to the clay-removed and SOM-removed subsoils, respectively. Conversely, 16.5 mg/kg and 12.9 mg/kg of the sorbed PYR was desorbed from the clay-removed and SOM-removed subsoils, respectively.

Adsorption↗
PubMed2003

An analysis of self-reported joint pain among New York farmers.

Data from the telephone interview portion of the New York State Farm Family Health and Hazard Surveillance Project were used to study the prevalence and predictors of joint pain in a cohort of farmers and farm residents. The participants were owner/operators, workers, and residents from a representative sample of farms from 12 New York counties. A total of 1706 participants completed a telephone interview on musculoskeletal conditions. Joint trouble was defined as self-reported aches, pain, or discomfort in the past year in each of five different joint areas. The 12-month prevalence of joint trouble was: lower back 41%, neck/shoulders 35%, knees 29%, hands/wrists 28%, and hips 15%. Using logistic regression modeling, significant risk factors for joint trouble were identified (p < 0.05). Older age and being female increased the risk of aches, pain, or discomfort in most joints. Being the owner/operator increased the risk of neck/shoulder and lower back trouble, and being a worker increased the risk of neck/shoulder trouble. Doing tractor work was associated with trouble in all five joint areas, and milking was associated with knee trouble. These findings indicate that personal risk factors and the intensity and nature of the farm work contribute to joint trouble. Ergonomic improvements to tractors and milking facilities should be a high priority.

Adolescent↗
PubMed2002

Biodegradability of aged pyrene and phenanthrene in a natural soil.

A study was conducted to evaluate the biodegradability of pyrene (PYR) and phenanthrene (PHE) aged in a natural soil. Both the single and binary systems were either biostimulated via a nutrient amendment or bioaugmented via an inoculation of the enriched bacteria and nutrients. Aging resulted in higher concentration of both compounds and smaller bacterial activity in the solution-phase. Surprisingly, the total biodegraded extent was greater in the aged soil system than in the freshly spiked system. As anticipated, biostimulation was not appropriate to attain an effective biodegradation in this study, and bioaugmentation achieved a substantial increase the total biodegradation extent. The above findings were attributed to indigenous Pseudomonas aeruginosa entering a stationary-phase during the 200-day aging and producing rhamnolipid biosurfactants. In addition, a different sampling technique (i.e., after vigorous hand-shaking) revealed a 15 times higher microbial population than the normal sampling from the stagnant solution. Therefore, PAH bioavailability in the aged soils can be underestimated when the microbial activity is determined only from the stagnant solution. Furthermore, cometabolism enhanced PYR degradation when PHE was present as a primary substrate.

Biodegradation, Environmental↗
PubMed2002

The impact of contact time on pyrene sorptive behavior by a sandy-loam soil.

Batch experiments with pyrene (PYR) were conducted to quantify the effect of contact time on its sorption and desorption behavior by a sandy-loam soil. Twenty-four and 48 h contact times were chosen for the nonequilibrium conditions and 240 h for the pseudoequilibrium study. All times was selected based on the kinetic results. The nonlinear, pseudoequilibrium sorption isotherm was fit to a two-stage Freundlich model: 3-7 mg/l for the first stage and 7-15 mg/l for the second stage. A substantial fraction of the sorbed PYR was not desorbed within the given desorption time. The reason of hysteresis was found to be a sorption enhancement due to soil hydration which provided more sorption sites. A desorption enhancement at 240-h desorption steps was attributed to the increased dissolved organic matter evolution. This study also found that both soil organic matter and clay materials had an equal role in PYR sorption enhancement and desorption resistance.

Adsorption↗
PubMed2002

Adult-to-adult living donor liver transplantation at the Asan Medical Center, Korea.

Between February 1997 and December 2001, 311 adult-to-adult living donor liver transplants (A-A LDLTs) were performed at the Asan Medical Center for patients above 20 years of age. Indications for A-A LDLT were: chronic hepatitis B (203), chronic hepatitis C (5), hepatocellular carcinoma (64), alcoholic cirrhosis (9), cryptogenic cirrhosis (4), secondary biliary cirrhosis (5), primary biliary cirrhosis (1), Wilson' s disease (2), autoimmune hepatitis (1), hepatic tuberculosis (1), cholangiocarcinoma (1), fulminant hepatic failure (14) and primary non-function of cadaveric liver graft (1). Of 311 A-A LDLTs, 36 were of medical high urgency, 20 were for acute and subacute hepatic failure, 15 were for hepato-renal syndrome and 1 was for primary non-function. Recipient age ranged from 27 to 64 years. Donor age ranged from 16 to 62 years. There was no donor mortality. Implanted liver grafts were categorized into seven types: 175 modified right lobe (MRL), 70 left lobe, 32 right lobe, 20 dual grafts, 10 left lobe plus caudate lobe, three extended right lobe and one posterior segment. In MRL, the tributaries of the middle hepatic vein were reconstructed by interpositioning a vein graft. Indication for dual graft implantation was the same as single graft A-A LDLT, and four of 20 were emergency cases. Of 20 dual grafts, 14 received two left lobes, four received a left lobe and a lateral segment, one received a right lobe and a left lobe and one received a lateral segment and a posterior segment. Graft volume ranged from 28% to 83% of the standard liver volume of the recipients. There were 33 (10.6%) in-hospital mortalities (< 4 months) among the 310 patients after 311 A-A LDLTs. Of the 36 patients receiving emergency transplants, 31 survived. These encouraging results justify the expansion of A-A LDLT in coping with increasing demands, even in urgent situations. We have aimed to introduce the establishment of the efficacy of A-A LDLT in various end-stage chronic and acute liver diseases, as well as new technical advances to overcome small graft-size syndrome by using dual-graft implantation and MRL, both of which were first developed in our department.

Adult↗
PubMed2001

Maximization of acetic acid production in partial acidogenesis of swine wastewater.

Swine wastewater was biologically treated to produce short-chain volatile organic acids (VOAs) in laboratory-scale continuously stirred tank reactors. The maximum production rates of acetic and butyric acids associated with simultaneous changes in pH and hydraulic retention time (HRT) were investigated, in which the degree of acidification of swine wastewater to the short-chain VOAs was <25% of influent chemical oxygen demand (COD) concentration. A constant inoculum system was used to minimize the experimental error due to the use of inconsistent inoculum. The inoculum system was operated with synthetic wastewater at 6000 mg soluble chemical oxygen demand per liter (pH 6.0) and 35 degrees C at 0.5 day hydraulic retention time. Response surface methodology was applied successfully to determine the optimum physiological condition for which the maximum rate of acetic acid production occurred, which was pH 5.90 and 0.88 day hydraulic retention time at 35 degrees C. The partial acidification process to manage swine waste should be operated in the optimum condition for acetic acid production because the optimum operating condition for butyric acid production approached the washout point.

Acetic Acid↗
PubMed2001

Fluoxetine and norfluoxetine concentrations in nursing infants and breast milk.

BACKGROUND: This study's goal was to characterize nursing infants' exposure to fluoxetine through breast milk and to identify variables for minimizing such exposure. METHODS: Nursing women on stable daily doses of fluoxetine were recruited into the study. Breast milk, maternal and infant serum concentrations of fluoxetine and norfluoxetine were determined with high-performance liquid chromatography. RESULTS: Nineteen nursing women one with a pair of dizygotic twins participated in the study. The women were on stable daily doses of fluoxetine (10-60 mg/day) and all but two took the medication during the last trimester of pregnancy. Fluoxetine was detectable in 30% (n = 6) of the nursing infant sera (< 1-84 ng/mL), whereas norfluoxetine was found in 85% (N = 17) (< 1-265 ng/mL). Peak breast milk concentrations occurred approximately 8 hours after maternal dosing and predicted norfluoxetine concentrations in infant serum. Maternal serum fluoxetine and norfluoxetine concentrations correlated highly with infant norfluoxetine concentrations. A daily maternal fluoxetine dosage of 20 mg or lower was significantly less likely to produce detectable concentrations of either fluoxetine or norfluoxetine in infants compared to higher daily dosages. No adverse effects were reported in any infant. CONCLUSIONS: Our findings demonstrate that maternal serum and peak breast milk concentrations of fluoxetine and norfluoxetine predict nursing infant serum norfluoxetine concentrations. In nursing women taking 20 mg/day or less of fluoxetine, infant serum concentrations were typically low.

Breast Feeding↗
PubMed2001

Cloning of BNIP3h, a member of proapoptotic BNIP3 family genes.

Apoptosis is regulated by interaction of antiapoptotic Bcl-2 family proteins with various proapoptotic proteins, several of which are also members of the Bcl-2 family. BNIP3 (formerly NIP3) is a proapoptotic mitochondrial protein classified in the Bcl-2 family based on limited sequence homology-3 (BH3) domain and COOH-terminal transmembrane domain. Sequence comparison of BNIP3 has indicated that there are several BNIP3 human homologs of this protein, like BNIP3L, Nix and BNIP3. We have cloned a new member of BNIP3 family from the cDNA library prepared from human dermal papilla cells and designated as BNIP3h. BNIP3h shows substantial homology with other BNIP3 family proteins. BNIP3h induced apoptosis from 24 hours after transfection in MCF7 cell lines and its apoptosis inducing activity is extended until 72 hours after transfection.

Amino Acid Sequence↗
PubMed2001

The transcriptional activity of cAMP response element-binding protein-binding protein is modulated by the latency associated nuclear antigen of Kaposi's sarcoma-associated herpesvirus.

A multifunctional transcription co-activator, cAMP response element-binding protein-binding protein (CBP)interacts with a number of cellular factors and participates in cell growth, transformation, and development. It is also targeted by many viral proteins for their transcriptional activity or for the regulation of cellular processes. Here, we report that the C/H3 region of CBP is targeted by the latency associated nuclear antigen (LANA) of Kaposi's sarcoma-associated herpesvirus (KSHV). LANA interferes with the interaction between CBP and c-Fos, a representative C/H3 region binding, cellular transcription factor, in vivo and in vitro. In addition, we found that LANA inhibits the transcriptional activity and the in vitro histone acetyltransferase activity of CBP, suggesting that LANA modulates the global transcriptional activities of infected cells through the interaction with CBP. These results indicate that KSHV follows one of the conserved strategies, which other viruses utilize for influencing the cellular processes.

Acetyltransferases↗
PubMed2001

Multi-organ, multi-lineage engraftment by a single bone marrow-derived stem cell.

Purification of rare hematopoietic stem cell(s) (HSC) to homogeneity is required to study their self-renewal, differentiation, phenotype, and homing. Long-term repopulation (LTR) of irradiated hosts and serial transplantation to secondary hosts represent the gold standard for demonstrating self-renewal and differentiation, the defining properties of HSC. We show that rare cells that home to bone marrow can LTR primary and secondary recipients. During the homing, CD34 and SCA-1 expression increases uniquely on cells that home to marrow. These adult bone marrow cells have tremendous differentiative capacity as they can also differentiate into epithelial cells of the liver, lung, GI tract, and skin. This finding may contribute to clinical treatment of genetic disease or tissue repair.

Animals↗
PubMed2001

Congestion of right liver graft in living donor liver transplantation.

BACKGROUND: Left liver graft from a small donor will not meet the metabolic demands of a larger adult recipient. One solution to this problem is to use a right liver graft without a middle hepatic vein (MHV). However, the need for drainage from the MHV tributaries has not yet been described. METHODS: Five right liver grafts without a MHV were transplanted in patients including two hepatitis B virus-cirrhosis, two fulminant hepatic failure and one secondary biliary cirrhosis. The graft weight ranged from 650 to 1,000 g, corresponding to 48 to 83% of the standard liver volume of the recipients. RESULTS: Two of five recipients were complicated with severe congestion of the right median sector immediately after reperfusion, followed by prolonged massive ascites and severe liver dysfunction. One of the patients died of sepsis with progressive hepatic dysfunction 20 days after the operation. CONCLUSIONS: Preservation and reconstruction of the MHV tributaries is recommended to prevent congestion of the right liver graft without MHV.

Body Weight↗
PubMed2001

Social functioning and quality of life comparisons between obsessive-compulsive and schizophrenic disorders.

Treatment of obsessive-compulsive disorder has focused almost exclusively on symptom reduction; however, deficits in social functioning and quality of life of individuals with this disorder may contribute more to their "burden," suffering, and disability. To gauge the significance of social dysfunction and quality of life of persons with obsessive-compulsive disorder (OCD), we made comparisons with a group of persons with schizophrenia matched for age and gender. Thirty-one patients with OCD participating in a partial hospital treatment program were compared with 68 schizophrenic outpatients participating in a day rehabilitation program. The Independent Living Skills Survey (ILSS) and Lehman Quality of Life Scale (QOL) were administered before and after treatment for both cohorts. QOL scores were significantly lower for the OCD patients both before and after treatment, but improved significantly during treatment. OCD and schizophrenic patients had similar scores on almost every domain of the ILSS at pretreatment. The OCD patients improved significantly on many of the domains of social and independent living skills as a result of treatment and acquired significantly greater skills by post-treatment than did their counterparts with schizophrenia; however, the performance of social and independent living skills by OCD patients remained less than satisfactory even in domains where they improved. In the areas of job and leisure skills, there were significant group-by-time interactions. We concluded that patients with severe OCD and patients with schizophrenia are equally socially impaired. However, OCD patients experience greater significant functional improvement with multimodal treatment.

Activities of Daily Living↗
PubMed2001

MRI phenotype is associated with response to doxorubicin and cyclophosphamide neoadjuvant chemotherapy in stage III breast cancer.

BACKGROUND: The preferred management for women with stage II or locally advanced breast cancer (LABC) is neoadjuvant chemotherapy. Pathologic response to chemotherapy has been shown to be an excellent predictor of outcome. Surrogates that can predict pathologic response and outcome will fuel future changes in management. Magnetic resonance imaging (MRI) demonstrates that patients with LABC have distinct tumor patterns. We investigated whether or not these patterns predict response to therapy. METHODS: Thirty-three women who received neoadjuvant doxorubicin and cyclophosphamide chemotherapy for 4 cycles and serial breast MRI scans before and after therapy were evaluated for this study. Response to therapy was measured by change in the longest diameter on the MRI. RESULTS: Five distinct imaging patterns were identified: circumscribed mass, nodular tissue infiltration diffuse tissue infiltration, patchy enhancement, and septal spread. The likelihood of a partial or complete response as measured by change in longest diameter was 77%, 37.5%, 20%, and 25%, respectively. CONCLUSIONS: MRI affords three-dimensional characterization of tumors and has revealed distinct patterns of tumor presentation that predict response. A multisite trial is being planned to combine imaging and genetic information in an effort to better understand and predict response and, ultimately, to tailor therapy and direct the use of novel agents.

Adult↗
PubMed2001

The study on the web-based Clinical Database Management System of Oriental Pulse Waveform.

There are many database-oriented sites on the web, which provide basic medical knowledge, hospital information, and medical counseling. However, there are only a few oriental pulse databases on the web. In this perspective, the goal of this study is to develop the Clinical Database Management System of Oriental Pulse Wave Form using the World Wide Web. Accordingly, this study has conducted researches in the Web-based diagnosis data management system of pulse waveform as well as the method of transmitting the data of pulse waveform. In order to set the standard for the documents of the pulse waveform of patients, the web-based clinical database management system has been developed.

Database Management Systems↗