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Biomedical subjects

Y J Hwang

Publications and source records attributed to Y J Hwang.

15 recordsLinked to original sources
PubMed2006

Percutaneous insertion of Zilver stent in malignant biliary obstruction.

BACKGROUND: We evaluated the clinical efficacy and technical feasibility of the percutaneously inserted self-expandable nitinol stent (Zilver stent) for palliation of malignant biliary obstruction. METHODS: Seventeen patients with malignant tumors involving the intra- or extrahepatic bile duct who presented with obstructive jaundice underwent percutaneous insertion of a self-expandable nitinol stent. We retrospectively reviewed the hospital records of patients and evaluated the technical feasibility on stent placement, complications, patient survival, and duration of stent patency. RESULTS: Percutaneous biliary stenting with 27 Zilver stents was performed in 17 patients with malignant biliary obstruction. Technical success was 95%. Malposition of the stent was encountered in one patient. Minor technical problems were encountered in two patients: the introducer tip was broken during stent insertion, so endoscopic removal was done. Mean follow-up period for the 17 patients was 182 days (range 29-485 days): nine patients died of progressive disease at a mean follow-up of 151 days (range 61-371days) after stent insertion and eight patients remained alive at the final follow-up of 216 days (range 29-485 days). The median survival period for all patients was 277 days. The stent occlusion rate was 26% and the mean patency period was 280 days. In five patients, seven stents were obstructed by tumor ingrowth and overgrowth. Stent patency rates were 100%, 100%, 75%, 61%, and 41% at 1, 2, 3, 6, and 12 months, respectively. A late complication, erosive bleeding of the hepatic artery by the stent, developed in one patient. CONCLUSION: Percutaneous biliary stenting using the nitinol stent is technically feasible and safe and clinically efficacious treatment for malignant biliary obstruction, even with a minor technical problem during stent insertion.

Aged↗
PubMed2006

Intracranial xanthoma: long-term follow-up MR findings.

SUMMARY: We report the serial MR findings and histologic features of intracerebral xanthoma in a patient with hyperlipidemia. MR imaging revealed nodule formations with variable degrees of edema and enhancement in the perivascular spaces. In some lesions, high-signal-intensity foci were observed on unenhanced T1-weighted images, which suggest lipid contents of the lesion.

Basal Ganglia↗
PubMed2005

Size removal on polyester fabrics by plasma source ion implantation device.

Plasma treatment was evaluated as an alternative clean desizing technology in this work. As indicated by weight loss, O2 plasma treatment efficiently removed sizing agents such as polyvintyl alcohol (PVA), polyacrylic acid esters and their mixture (MIX) on polyethylene terephthalate (PET) fabrics. SEM pictures of the plasma treated samples directly proved the disappearance of the sizing agents. XPS analysis showed apparent changes in chemical composition and functional groups of the PET surface after O2 plasma treatment. Carbon content decreased due to the removal of sizing agents while oxygen content increased. O2 plasma treatment also increased hydrophilic functional groups of sizing agents, which is confirmed by C1s and O1s deconvolution analyses. After O2 plasma treatment, the PET fabric was subjected to conventional desizing process at different temperatures. Except for the PET fabric sized with PVA, plasma-treated fabrics showed more efficient desizing results when compared with untreated fabrics. Furthermore, the desizing effluent from the treated fabric gave lower TOC, COD and BOD values.

Acrylic Resins↗
PubMed2004

Functional and genetic assessment of IFN-gamma receptor in patients with clinical tuberculosis.

OBJECTIVE: The molecular basis of the genetic vulnerability underlying the most common form of clinical tuberculosis (TB) remains largely unknown. We speculated that mild genetic defects in the interferon-gamma (IFN-gamma) signalling pathway caused a subtle functional impairment of IFN-gamma which would explain susceptibility to Mycobacterium tuberculosis in clinical TB. DESIGN: A case-control study. RESULTS: We evaluated functional responsiveness to IFN-gamma in monocytes from patients with clinical TB (n = 10), and analysed the genetic sequences of the IFN-gamma receptor 1 (IFN-gammaR1) and STAT1 genes in patients with disseminated TB (n = 18). IFN-gamma stimulated an increase in the expression of HLA-DR and CD64 on monocytes of both controls and patients; the rate of increase in expression was the same in both groups. Treatment with IFN-gamma before lipopolysaccharide (LPS) stimulation further increased tumour necrosis factor-alpha (TNF-alpha) production as compared to TNF-alpha production with LPS stimulation alone; the rate of increase in TNF-alpha production was the same in both groups. The known mutations in the coding sequences of the IFN-gammaR1 and STAT1 genes were not found in the patients with disseminated tuberculosis. CONCLUSION: These results suggest that impairment of the IFN-gamma signalling pathway did not account for cases of clinical TB in this study.

Adult↗
PubMed2002

Diffusion-weighted magnetic resonance imaging in Wernicke's encephalopathy.

OBJECTIVE: To report diffusion-weighted imaging (DWI) findings and postulate the pathogenic mechanism of Wernicke's encephalopathy (WE). PATIENT: A 47-year-old-woman presented with altered consciousness, ophthalmoplegia, and ataxia. DWI revealed the abnormal signal changes in periaqueductal gray matter, mamillary bodies and bilateral medial thalami. Apparent diffusion coefficient (ADC) map revealed the high signal intensity lesions in bilateral medial thalami, suggestive of vasogenic edema. The abnormal signal intensity lesions disappeared on follow-up imaging with clinical improvement. CONCLUSIONS: Vasogenic edema plays an important role in the pathogenesis of WE and can be reversed by proper management. DWI findings in the early stage of WE may provide useful information about the prognosis.

Brain↗
PubMed2001

Tumor apoptosis in cervical cancer: its role as a prognostic factor in 42 radiotherapy patients.

To investigate tumor apoptosis as a prognostic factor for outcome following radiation therapy, comparisons were made of apoptotic index (AI) as a predictor of short- vs. long-term response and pretreatment vs. radiation-induced apoptosis. Forty-two patients with proven squamous cell carcinoma of the uterine cervix were treated by radiation alone. Apoptosis was measured by light microscopic observation of hematoxylin and eosin-stained sections from biopsies taken before treatment and 4 and 24 hr after 2 Gy. Patients were evaluated at the end of the external radiation for determination of short-term response and for long-term outcome as well (median follow-up of 27 months). Patients with high spontaneous AI showed poor short-term response, local control, and survival. The significance of AI as a predictor of short-term response was lost after allowing for differences in tumor size. The positive predictive value of AI for local control and survival was independent of tumor size and stage. High AI was associated with poor local control and long-term prognosis in advanced squamous cell carcinoma of the cervix. The in vivo radiation-induced AI after 4 or 24 hr did not predict radiation therapy outcome.

Adult↗
PubMed2000

Immunization of cultured juvenile rockfish Sebastes schlegeli against Microcotyle sebastis (Monogenea).

To determine whether immunization with Microcotyle sebastis antigen could induce protection against the parasite's establishment, naive juvenile rockfish were immunized by injection or immersion with whole worm antigen of M. sebastis. The infestation intensities of immunized groups following a challenge (2 wk after boosting) with 5000 M. sebastis eyed-eggs were significantly lower than those of control groups, when determined 7 wk postinfection. The fish in the groups boosted with M. sebastis antigen showed stronger protection than unboosted groups. The control group injected with FCA only showed a significantly smaller number of worms than the control group, which was immersed in PBS containing seawater. The results strongly suggest that both specific and nonspecific immune factors participate in the protection of rockfish against M. sebastis establishment.

Animals↗
PubMed1999

Successful resection of cecal hepatic metastasis extending into the right side of the heart under cardiopulmonary bypass.

Resection is the best hope for the cure of colorectal metastasis to the liver. However, surgery is indicated for only a few patients, especially those who have major vascular involvement. We report a 55-year-old woman with a liver metastasis from the cecum that showed a tumor thrombus in the right side of the heart. She had undergone laparoscopic right hemicolectomy for cecal cancer 6 months before, and presented with a palpable mass in the epigastrium. Abdominal ultrasonography, computed tomography, hepatic angiogram, and echocardiography showed a huge mass on the left lobe of the liver, with a tumor thrombus which extended to the right ventricle through the left hepatic vein and inferior vena cava. Tumor thrombectomy, through a right atriotomy, was success-fully performed under cardiopulmonary bypass, followed by left hepatic lobectomy. The patient's postoperative course was uneventful.

Adenocarcinoma↗
PubMed1997

A simple method of reduction malarplasty.

The Oriental face is generally mesocephalic: short and wide. Thus the prominent zygoma in relation to a flat nose will make the face seem flatter. The unfavorable social connotations associated with a prominent zygoma are a reality in Korea. Reduction will not only relieve the patient of such psychological burdens but also afford a face with a cheerful and youthful appearance. Thus not a few patients seek surgery for these reasons. Previously, chiseling or burring of the zygoma body and arch was frequently used for zygoma reduction but was usually less than effective in reducing the wide face. Segmental osteotomy and repositioning of the arch by means of a bicoronal approach was another method, but this involved an extensive operation and left a long visible scar. We left that these methods were less than ideal as aesthetic procedures. A simple and yet effective method of reducing the prominent zygoma was needed. Reduction of the prominent zygoma was performed in 26 patients by shaving the zygoma body and displacing the zygomatic arch inwardly after two-point fracturing, greenstick fracture anteriorly, and complete osteotomy posteriorly by means of a small preauricular and upper buccal sulcus incision. We obtained satisfactory results using the relatively simple procedure. The advantages of our technique are as follows: (1) there is a small skin incision and resulting inconspicuous scar, (2) the technique is simple and effective, (3) there is no use of foreign bodies such as wires on miniplates, and (4) there is less postoperative discomfort.

Adult↗
PubMed1996

A simple method for detecting human polyomavirus DNA in urine by the polymerase chain reaction.

In order to develop a simple and sensitive method for detecting human polyomavirus DNA in the urine of patients by the polymerase chain reaction (PCR), it was found that the viral DNA could be released from urine by proteinase K and then amplified by PCR directly, without additional treatment such as ultracentrifugation or DNA extraction. Direct PCR amplification of viral DNA from urine was volume limited and 5 microliters of urine appeared to be the optimum amount for direct PCR amplification. When the urine volume was greater than 10 microliters, the results of PCR were inconsistent. However, the urine volume could be increased after dialysis to remove possible inhibitor(s) which may interfere with PCR. Direct PCR amplification of patient urine is convenient and eliminates several steps which can cause loss of DNA from the sample.

DNA, Viral↗
PubMed1996

A hospital-based, case-control study of risk factors for hemorrhagic fever with renal syndrome in soldiers of the armed forces of the Republic of Korea.

A hospital-based, case-control study was conducted to measure risk factors for hemorrhagic fever with renal syndrome in Korean soldiers. Between October 1989 and January 1992, 196 cases and 295 controls were admitted into the study. Information was collected on behavioral and environmental variables, and the data were analyzed by multiple logistic regression. The strongest risk factors were seeing Apodemus in the area (odds ratio [OR] = 4.9), living in a primitive dwelling such as a lean-to (OR = 3.9), and being exposed to dust (OR = 3.7). The most protective factors were living in barracks (OR = 0.3-0.5) and self-reported use of any insecticide or insect repellent (OR = 0.5).

Adult↗
PubMed1983

The results of radiation therapy in advanced carcinoma of the lung in the Beijing region of China.

From 1958 to 1973, 682 patients with lung cancer were treated by radiation therapy in the Cancer Institute, Chinese Academy of Medical Sciences, Beijing, China. The clinical presentation, sex, age, histology and stage and palliative effects of radiation therapy were reported. The 1-, 3- and 5-year survival rates were 40.62, 8.94 and 3.81%, respectively. The prognostic factors such as staging, histology, combination with chemotherapy and response of tumours are discussed. The causes of failure are also analysed. It is suggested that improving the local control rate of squamous cell carcinoma would increase the survival rate.

Adenocarcinoma↗