Biomedical subjects

K H Chung

Publications and source records attributed to K H Chung.

At least 55 records · Page 3Linked to original sources

PubMed1999

The changes of ventilatory parameters in laparoscopic colecystectomy.

We investigated the ventilatory changes in healthy patients without cardiopulmonary pathology during elective laparoscopic cholecystectomy in the head-up position. During surgery, intraabdominal pressure was maintained at 15 mmHg by a CO2 insufflator, and minute ventilation was controlled with a constant tidal volume and fixed respiratory rate. PETCO2 was monitored continuously and recorded every minute. Basic hemodynamic and ventilatory parameters were measured before anesthesia; after induction of anesthesia; at 5 min, 10 min and 30 min after peritoneal insufflation; and 5 min and 10 min after exsufflation. Arterial blood samples were obtained 3 times to calculate D(a-A)CO2, VD/VT, and Vco2. The latent period of PETCO2 change was 2.9 min, the ascending period was 12.6 min, and the descending period was 12.2 min. During the 71.5 min of pneumoperitoneum, V(I), VE, peak and plateau Paw increased, while Cdyn decreased significantly. Peritoneal insufflation or exsufflation also resulted in a significant change of D(a-A)CO2, D(a-A)O2, and Vco2. The anesthesiologist must be aware of both hemodynamic and ventilatory changes and must be ready to respond promptly and adequately.

Adolescent↗

PubMed1999

Matrix metalloproteinase-1 expression is a prognostic factor for patients with advanced gastric cancer.

Proteolytic activity of cancer cells is an important factor in metastasis. This study examined the relationship between MMP-1 expression of gastric cancer cells and peritoneal metastasis. MMP-1 expression was found in 76/103 (75.2%) cases examined and was significantly associated with both peritoneal metastasis and lymph node metastasis (p<0.05, respectively). The prognosis of patients with MMP-1 positive tumor was significantly worse than that of patients with MMP-1 negative tumor (p<0.05). These findings suggested that MMP-1 might be a prognostic factor in case of advanced gastric cancer and might be useful in determining whether or not adjuvant therapy was indicated for patients at high risk of peritoneal recurrence.

Adult↗

PubMed1998

Purification and molecular cloning of a platelet aggregation inhibitor from the snake (Agkistrodon halys brevicaudus) venom.

A platelet glycoprotein IIb-IIIa (GP IIb-IIIa) antagonist, salmosin, was purified to homogeneity from Korean snake (Agkistrodon halys brevicaudus) venom by means of chromatographic fractionations. We have isolated the cDNA encoding salmosin by using the cDNA library of the snake venom gland and analyzed its complete nucleotide sequence. The molecular identity was confirmed by comparison of the deduced amino acid sequence with the directly determined primary structure of salmosin. This protein is a single-chain polypeptide composed of 73 amino acids including 12 cysteines as well as the sequence Arg-Gly-Asp, a proposed recognition site of adhesive proteins. The primary sequence of salmosin shows considerable homology to previously described proteins of snake venom GP IIb-IIIa antagonist family. A molecular mass of 7474 for the protein was determined by matrix-assisted laser desorption ionization mass spectrometry. Salmosin inhibits GP IIb-IIIa binding to immobilized fibrinogen with an IC50 of 2.2 nM and ADP-induced platelet aggregation with an IC50 of 131 nM, respectively. This work demonstrates the purification, characterization, and cDNA cloning of salmosin, a platelet aggregation inhibitor that may have therapeutic potential as an antithrombotic agent.

Agkistrodon↗

PubMed1998

Changes in tumor marker levels as a predictor of chemotherapeutic effect in patients with gastric carcinoma.

BACKGROUND: Evaluating chemotherapeutic effect in patients with gastric carcinoma sometimes is difficult. The authors investigated whether changes in the serum levels of three tumor markers can be used to predict the clinical outcome after chemotherapy. METHODS: Thirty patients with advanced and recurrent gastric carcinoma were treated with continuous 5-fluorouracil and low dose cisplatin for 4 weeks. Thirteen patients were treated neoadjuvantly prior to gastrectomy. The serum levels of carcinoembryonic antigen, carbohydrate antigen 19-9, and sialyl-Tn antigen were measured prior to and after chemotherapy. Responders were defined as those in whom abnormal serum levels of all three markers decreased to at least 50% of the pretreatment values and remained stable for at least 1 month. RESULTS: The tumor markers could be evaluated in 27 of 30 patients (90%). The median duration of survival for the 15 responders and 12 nonresponders was 17 months and 6 months, respectively. There was a significant difference in the median duration of survival between the responders and nonresponders using the log rank test (P=0.0005). In the patients who received neoadjuvant therapy, the eight responders had a significantly longer survival period than did the three nonresponders (P=0.018). Seven of the eight responders showed evidence of tumor destruction histologically whereas none of the three nonresponders did. CONCLUSIONS: Changes in the serum levels of these tumor markers after chemotherapy may be an excellent prognostic indicator for patients with gastric carcinoma.

Adult↗

PubMed1998

Demographic characteristics of zipeprol-associated deaths in Korea.

The abuse of zipeprol, an antitussive agent, was found to be most prevalent among young people in Korea. Because abusers take large doses of this drug for its hallucinogenic effects, fatalities from zipeprol overdose abuse have been on the rise since 1991. Since 1991, a total of 69 zipeprol-related deaths have occurred throughout the nation. A demographic study shows that in ninety six percent of cases involving ziperol alone, the victims were in their teens and twenties. The male/female ratio in zipeprol related death was 3.5:1. Most of these zipeprol-associated deaths occurred in the larger cities of Seoul and Inchon. The blood concentration of zipeprol ranged from 0.8 to 38.3 micrograms/mL in single drug involved deaths, while zipeprol varied from 0.1 to 35.3 micrograms/mL in zipeprol and dextromethorphan victims.

Adolescent↗

PubMed1998

p53 protein overexpression as a predictor of the response to chemotherapy in gastric cancer.

This study was performed to evaluate p53 overexpression as a predictor of the response to chemotherapy of patients with gastric cancer. The subjects comprised 20 patients with Stage IV gastric cancer and three with locally recurrent lesions, all of whom were treated with 5-fluorouracil (5-FU) plus cisplatin (CDDP) for 4 weeks. Of the total 23 patients there were 10 responders; 2 showing complete response (CR) and 8, partial response (PR). Specimens obtained by endoscopic biopsy were immunohistochemically stained using anti-p53 protein and bcl-2 protein antibody. Of the 10 responders, 7 demonstrated negative p53 staining, and of the 13 nonresponders, 11 demonstrated positive p53 staining (P = 0.013). Tissue from 3 of the responders and 7 of the nonresponders that stained for bcl-2 were positive prior to chemotherapy; however, there was no association between bcl-2 staining and chemotherapeutic effect. In conclusion, immunohistochemical identification of p53 in pretreatment tissue may represent a useful predictor for chemotherapeutic outcome in patients with gastric cancer.

Adult↗

PubMed1998

Serum soluble interleukin-2 receptor level as a prognostic indicator in gastric cancer.

T lymphocytes, activated by interleukin 2 during an anti-tumour response, release soluble interleukin 2 receptors (sIL-2R) into the bloodstream. We analysed the prognostic value of the serum sIL-2R level in gastric cancer. Serum concentration of sIL-2R in 96 gastric cancer patients and 100 healthy control subjects' was measured by enzyme-linked immunosorbent assay. All survivors were followed for more than 50 months. Serum sIL-2R level was considered with respect to prognosis, clinicopathological factors, other tumour markers and peripheral blood cell count. Stage III and IV patients had significantly higher sIL-2R levels than lower stage patients and control subjects. Stage III and IV gastric cancer patients were divided into 'high' and 'low' slL-2R groups based upon the control subjects' serum sIL-2R mean value plus one standard deviation. The high group had a significantly worse prognosis than the low group, although clinicopathological features and treatments were similar. Multivariate analysis demonstrated that the serum sIL-2R level is an independent indicator. The sIL-2R level did not correlate with carbohydrate antigen 19-9, however it did correlate with carcinoembryonic antigen (r = 0.22) and with numbers of peripheral blood monocytes (r = 0.54). In conclusion, serum sIL-2R may predict the outcome of gastric cancer patients with stage III or IV disease.

Adult↗

PubMed1998

Stimulatory effects of high-fat diets on colon cell proliferation depend on the type of dietary fat and site of the colon.

To compare the effects of various types of dietary fat on colon cell proliferation used as an intermediate biomarker for colon carcinogenesis, groups of 10 male Sprague-Dawley rats were fed one of four high-fat diets (45% of total calories from corn oil, butter, beef tallow, and fish oil) for three weeks. As a control, a low-fat diet (15% of total calories from corn oil) was fed to a separate group. Cell proliferation was measured by in vivo incorporation of bromodeoxyuridine into DNA in the proximal and distal colon. Total lipids in feces were measured by a gravimetric method. There were significant differences in colon cell proliferation among the diet groups, where the high corn oil diet stimulated cell proliferation in proximal and distal colon compared with the high fish oil diet (p < 0.05). The protective effect of the high fish oil diet on cell proliferation was similar to that of the low corn oil diet. The effects of high beef tallow and butter diets on colon cell proliferation were highly dependent on sites of the colon, because the hyperproliferative effects by these diets were found only in the distal colon (p < 0.05). Fecal total lipids and fecal lipid concentrations were significantly affected by the dietary fat sources, in that the groups fed the saturated fats, such as butter and beef tallow, excreted more lipids into feces than did the groups fed the unsaturated fats, such as corn oil and fish oil. Fecal lipids were significantly correlated to colon cell proliferation in the way that distal colon cell proliferation increases as fecal lipids increase. Therefore, these data suggest that high levels of dietary fats may not always promote colon carcinogenesis, and the effects may be dependent on the types of dietary fat and sites of the colon.

Animals↗

PubMed1998

Granular cell tumor of the duodenum: a case report.

Granular cell tumor (GCT) in the duodenum is an extremely rare disease: only one case has been listed in a review, to date. We reported a 47-yr-old Japanese male case with GCT of the duodenum. Clinically, melena caused by bleeding from the tumor was the only symptom. The tumor cells showed abundant, granular eosinophilic cytoplasm. Although this tumor was clinically and histologically benign, highly developed tumor microvessels were demonstrated both angiographically and histologically, suggesting malignant potential of the tumor.

Duodenal Neoplasms↗

PubMed1998

Thymidine phosphorylase activity in tumor correlates with venous invasion.

Thymidine phosphorylase (dThdPase) is identical to platelet-derived endothelial cell growth factor (PD-ECGF), an angiogenesis factor. We investigated the correlation between dThdPase activity in gastric cancer tissue and clinicopathological factors. Thirty-three cancer tissue specimens and 23 adjacent normal gastric mucosal specimens were obtained from surgery. Measurement of dThdPase activity was based on the amount of 5-fluorouracil formed from 5'-deoxy-5-fluorouridine by dThdPase. Mean dThdPase activity in cancer tissue was approximately 3.2 times higher than that in normal tissue. Cancerous tissues with venous invasion had about twice the dThdPase activity as cancerous tissues without venous invasion. Other clinicopathological features were not related to dThdPase activity. A correlation between dThdPase activity and immunosuppressive acidic protein level was observed (r = 0.532, P = 0.005). dThdPase activity in gastric cancer cells was found to be correlated with venous invasion, supporting previous findings that it plays a role in tumor angiogenesis.

Adult↗

PubMed1998

Expression of the mismatch repair gene hMSH2 in sporadic colorectal cancer.

At least four genes involved in DNA mismatch repair (MMR), hMSH2, hMLH1, hPMS1 and hPMS2, have been cloned and characterized. These genes have been demonstrated to be altered in the germline of patients with hereditary non-polyposis colorectal cancer (HNPCC). HNPCC is an autosomal dominant disease characterized by a preponderance of proximal colon, young age of onset, increased multiplicity, and improved stage-specific survival. In this study, we examined the expression of hMSH2 protein in sporadic colorectal cancer (CRC). As a result, the frequency of right-sided CRC and multiple CRCs were significantly higher in the patients with hMSH2-negative CRC than in those with hMSH2-positive CRC. The rate of p53 positivity was significantly lower in the hMSH2-negative tumours than that in the hMSH2-positive tumours. The disease-free survival rate tended to be higher in the patients with hMSH2-negative CRC than in the patients with hMSH2-positive CRC. Our findings suggest that both the clinicopathological and biological features of hMSH2-negative sporadic CRC seemed to be similar to those of HNPCC. To clarify the mechanism of carcinogenesis in HNPCC and sporadic CRC, further investigations of genetic alterations caused by MMR genes will be needed.

Adult↗

PubMed1997

Hepatitis C virus E2 protein purified from mammalian cells is frequently recognized by E2-specific antibodies in patient sera.

The envelope protein of hepatitis C virus (HCV) is composed of two membrane-associated glycoproteins, E1 and E2. To obtain HCV E2 protein as a secretory form at a high level, we constructed a recombinant chinese hamster ovary (CHO) cell line expressing a C-terminal truncated E2 (E2t) fused to human growth hormone (hGH), CHO/hGHE2t. The hGHE2t fusion protein was purified from the culture supernatant using anti-hGH mAb affinity chromatography at approximately 80% purity. The purified hGHE2t protein appeared to be assembled into oligomers linked by intermolecular disulfide bond(s) when density gradient centrifugation and SDS-polyacrylamide gel electrophoresis were employed. When the purified fusion protein was used for testing its ability to bind to antibodies specific for HCV by enzyme-linked immunosorbent assay, the protein was recognized by antibodies in sera from 90% of HCV-positive patients. Treatment of hGHE2t protein by beta-mercaptoethanol, but not by heat and SDS, significantly reduced its reactivity to the antibodies of patient sera, suggesting that intermolecular and/or intramolecular disulfide bonds are important for its ability to recognize its specific antibody and that the E2 protein contains discontinuous antigenic epitope(s).

Animals↗

PubMed1997

Bonding strengths of porcelain repair systems with various surface treatments.

STATEMENT OF PROBLEM: Metal porcelain combined surfaces are often involved in the repairing of fractured porcelain fused to metal restoration. PURPOSE: This study investigated the effect of surface treatments on the bonding strength of porcelain fused to metal prosthesis repair. MATERIAL AND METHODS: Specimens (8 x 4 mm) were fabricated with Biobond II casting alloy and randomly divided into three surface groups: metal, porcelain, and metal-porcelain combined surface. Biobond porcelain system and commercially available porcelain repair systems were tested. The metal surface group was further divided into two subgroups: control and sandblasting treatment (Al2O3, 50 microns, 20 seconds). In the porcelain surface group, there were three subgroups: (1) control, (2) sandblasting, and (3) 9.5% hydrofluoric acid etching for 4 minutes. The metal-porcelain surface combined group was divided into three subgroups: (1) control, (2) sandblasting, and (3) sandblasting and etching. The manufacturer's instructions for repair systems were followed for specimen preparation. Shear bond strengths of 10 specimens for each subgroup were determined with a universal testing machine after storing in distilled water at 37 degrees C for 7 days. The data were analyzed with analysis of variance and Scheffé F-test at the 95% significance level. RESULTS: The Liner-M repair system showed significantly greater strength than the other tested systems on the metal surface with or without sandblasting treatment (p < 0.05). On the porcelain surface, the strengths of sandblasting and etching subgroups ranged from 7.2 to 16.8 MPa, and 6.8 to 16.8 MPa, respectively. There were no significant differences in bond strengths between sandblasting and combined treatment of the metal-porcelain combined surface group (p > 0.05). CONCLUSION: The results of this study suggest that metal substrates treated with sandblasting and porcelain treated with either hydrofluoric acid or sandblasting can increase repair strength.

Dental Bonding↗

PubMed1997

The effects of sprue design on the roughness and porosity of titanium castings.

PURPOSE: This study measured the effects of the sprue number and position on the roughness and porosity of cast titanium crowns. MATERIAL AND METHODS: Twenty-four complete veneer crown wax patterns were fabricated on a stainless steel die with a 30-degree bevel finish line. Twelve wax patterns were sprued with one 8-gauge wax sprue and the remaining 12 were double sprued. All patterns were invested with a phosphate bonded investment. Castings were made with a titanium casting, according to the manufacturer's instructions, with commercially pure titanium (> 99.5%) ingots. The castings were carefully cleaned and the surface roughness was measured with a profilometer. The specimens were then embedded and sectioned. Internal porosities were quantified with photographs by computerized image analysis. Data were analyzed with an ANOVA and the Student's t test with a confidence level of 95%. RESULTS: The roughness value of the occlusal third of the crowns for the single sprue group (Ra = 3.0 +/- 0.9 microns) was significantly higher than other measurements (p < 0.05). There were statistically significant differences in values of porosity areas between the single sprue group (1.5 +/- 0.7 mm2) and the double sprue group (0.2 +/- 0.2 mm2) (p < 0.01). The double sprue design resulted in a relatively smoother casting surface and less internal porosity than the single sprue design. CONCLUSIONS: Improvements in the degree of roughness and porosity of titanium crown castings were the result of the double sprue design.

Analysis of Variance↗

PubMed1996

Arrested development of the neonatal kidney following chronic ureteral obstruction.

PURPOSE: The purpose of this study was to investigate the role of growth-related peptides in the impairment of renal growth and development resulting from unilateral ureteral obstruction (UUO) in the neonatal rats. MATERIALS AND METHODS: Sprague-Dawley rats underwent UUO or sham-operation in the first 48-hours of life, and kidneys were harvested 1 to 28 days later. Renal messenger RNA (mRNA) was quantitated for renin, transforming growth factor-beta 1 (TGF-beta 1) and epidermal growth factor (EGF). Renal interstitial volume was measured in Masson-trichrome-stained sections, and renin and alpha-smooth muscle actin (alpha-SM actin) distribution were determined by immunocytochemistry. RESULTS: The normal developmental increase in renal mass and DNA content were suppressed in ipsilateral UUO and increased in the intact opposite kidney. Renal interstitial volume was increased more than 10-fold by ipsilateral UUO. Unilateral ureteral obstruction resulted in a sustained increased in ipsilateral renal renin mRNA and persistence of fetal renin distribution. Renin in the contralateral kidney was suppressed. Transforming growth factor-beta 1 expression increased progressively in the obstructed kidney, but decreased after 7 days in sham-operated kidneys. While renal EGF expression was undetectable in the normal sham kidney during the first 3 days of life, it increased steadily with maturation. However, EGF expression remained suppressed in the obstructed kidney. Whereas alpha-SM actin disappeared from the interstitium of normal rat kidneys by 15 days of age, it persisted in the obstructed neonatal kidney. CONCLUSIONS: As revealed by changes in expression of growth-related peptides, neonatal UUO delays ipsilateral renal development, which may contribute to impaired renal growth.

Actins↗

PubMed1996

Fetal sex as a risk factor for fetal distress leading to abdominal delivery.

A retrospective analysis of perinatal information of 7,924 confinements in the calendar year of 1994 was performed to determine whether fetal sex was a significant risk factor for fetal distress in labour leading to abdominal delivery. The sex of the fetus (male) was a significant, independent, risk factor for Caesarean section (odds ratio = 1.26, 95% CI = 1.05 to 1.50). This increase was wholly attributable to the increased risk of having fetal distress in labour (odds ratio = 1.76, 95% CI = 1.32 to 2.34). Male fetuses are at higher risk of developing fetal distress during labour.

Cesarean Section↗

PubMed1996

Studies on the synthesis and structure-activity relationships of 2-(2-functionalized pyrrolidin-4-ylthio)-1 beta-methylcarbapenems.

A series of new carbapenem derivatives, which have a pyrrolidin-4-ylthio group substituted with a hydroxyalkyl or carbamoyl group at the 2' position as the C-2 side chain, have been prepared. The antibacterial activity and the stability to renal dehydropeptidase-I of these compounds were investigated, and the structure-activity relationships were studied. Among these new carbapenems, (1R,5S,6S)-2-[(2S,4S)-2-¿(2-hydroxy)ethylmercaptomethyl¿pyrroli din-4 -ylthio]-6-[(1R)-I-hydroxyethyl]-1-methyl-1-carbapen-2-em-3- carboxylic acid (1a) showed the most potent and well balanced activity and was selected as a candidate for further evaluation.

Animals↗

PubMed1996

Efficacy of ciprofloxacin and dexamethasone in experimental pseudomonas endophthalmitis.

To determine injection time and effective dose of ciprofloxacin in endophthalmitis and to evaluate the effectiveness of dexamethasone. In rabbits, Pseudomonas aeruginosa (2 x 10(4) CFU/0.1 ml) was inoculated intravitreally. At 6, 12, 18, 24 hours postinoculation, single intravitreal doses of ciprofloxacin (300 micrograms/0.15 ml or 100 micrograms/0.05 ml) alone or with dexamethasone (400 micrograms) were given. Electrophysiological and histologic measures were utilized to rate drug effectiveness. 300 micrograms ciprofloxacin was effective in killing P. aeruginosa at 6 and 12 hours postinoculation, but one hundred ug ciprofloxacin was not effective. 300 ug ciprofloxacin had no significant effect in killing P. aeruginosa at 18 hrs and 24 hrs postinoculation. Eyes treated with dexamethasone (400 micrograms) and ciprofloxacin (300 micrograms) at 6 hours postinoculation did not differ from eyes treated with ciprofloxacin alone. Cultures from eyes treated with dexamethasone and ciprofloxacin at 12 hours postinoculation were positive. Cultures from eyes treated with ciprofloxacin alone were negative. The failure of treatment at 18 hrs and 24 hrs postinoculation may be due to either an increased rate of clearance of drugs from the eyes or a reduced bactericidal effect of ciprofloxacin which could be altered by acidic pH, degree of hypoxia or bacterial counts. Dexamethasone had no beneficial effect in the treatment of P. aeruginosa endophthalmitis in the early phase.

Animals↗