Search PubMed⌕ Search

Biomedical subjects

K S Cho

Publications and source records attributed to K S Cho.

125 records · Page 7Linked to original sources
PubMedDate not supplied

Color Doppler flow imaging of hepatocellular carcinomas. Comparison with metastatic tumors and hemangiomas by three-step grading for color hues.

The role of color Doppler imaging was evaluated in differentiating hepatocellular carcinomas (HCCs) from metastases and hemangiomas by the amount of tumoral color signals. Intratumoral and peritumoral color signals were analyzed by a three-step grading system (grade 1 to 3) in 51 patients (32 HCCs, seven metastases, and 12 hemangiomas). Correlation of grading scores for intratumoral and peritumoral color signals was evaluated with the size of the tumors as well. HCCs demonstrated a higher grade of intratumoral color signals than did metastases or hemangiomas in all (p < 0.05) and biopsy-proved lesions (p = 0.0084); there was no significant difference in the degree of peritumoral color signals in all (p > 0.05) or 17 biopsy-proved HCCs (p = 0.2078) from the other tumor groups. In addition, the grade of both intratumoral and peritumoral color signals was not related with the tumor size in all groups (p > 0.05). In conclusion, color Doppler imaging provided a valuable role in the diagnosis of HCCs based on the qualitative analysis of the intratumoral color signals.

Adult↗
PubMedDate not supplied

Recovery of poly(3-hydroxybutyrate) from coagulated Ralstonia eutropha using a chemical digestion method.

For economic recovery of poly(3-hydroxybutyrate) (PHB) from culture broths of Ralstonia eutropha containing PHB, Al-based and Fe-based coagulants were used in the pretreatment step. The coagulated cells were then separated by centrifugation, and PHB was extracted by chemical digestion with a sodium hypochlorite/chloroform dispersion solution. The practical upper limits of dosage were found to be 1, 500 mg-Al/L and 1,000 mg-Fe/L, respectively, for Al- and Fe-based coagulants. When the harvested cells were treated with a 50% sodium hypochlorite/chloroform dispersion solution, PHB recovery and purity were 90-94% and 98-99%, respectively. The influence of the use of coagulants on the PHB recovery process was found to be insignificant. Despite the residual Al and Fe in the recovered PHB (less than 450 mg-Al/kg-PHB and 750 mg-Fe/kg-PHB, respectively), no detectable amounts of Al and Fe were leached from films made of the recovered PHB under acidic conditions. The use of Fe-based coagulants is less recommended because the Fe impurity can cause an unwanted colorization problem in the final product.

Biocompatible Materials↗
PubMedDate not supplied

Production of a desulfurization biocatalyst by two-stage fermentation and its application for the treatment of model and diesel oils.

For the production of oil-desulfurizing biocatalyst, a two-stage fermentation strategy was adopted, in which the cell growth stage and desulfurization activity induction stage were separated. Sucrose was found to be the optimal carbon source for the growth of Gordonia nitida CYKS1. Magnesium sulfate was selected to be the sulfur source in the cell growth stage. The optimal ranges of sucrose and magnesium sulfate were 10-50 and 1-2.5 g x L(-1), respectively. Such a broad optimal concentration of sucrose made the fed-batch culture easy, while the sucrose concentration was maintained between 10-20 g x L(-1) in the actual operation. As a result, 92.6 g x L(-1) of cell mass was acquired by 120 h of fed-batch culture. This cell mass was over three times higher than a previously reported result, though the strain used was different. The desulfurization activity of the harvested cells from the first stage culture was induced by batch cultivation with dibenzothiophene as the sole sulfur source. The optimal induction time was found to be about 4 h. The resting-cell biocatalyst made from the induced cells was applied for the deep desulfurization of a diesel oil. It was observed that the sulfur content of the diesel oil decreased from 250 mg-sulfur x L-oil(-1) to as low as 61 mg-sulfur x L-oil(-1) in 20 h. It implied that the biocatalyst developed in this study had a good potential to be applied to a deep desulfurization process to produce ultra-low-sulfur fuel oils.

Air Pollution↗
PubMedDate not supplied

Separation of Alcaligenes eutrophus cells containing Poly(3-hydroxybutyrate) from fermentation broth with pretreatment using Al- and Fe-based coagulants.

Alcaligenes eutrophus containing intracellular poly(3-hydroxybutyrate) was recovered from fermentation broth by centrifugation and filtration after pretreatment with Al- and Fe-based coagulants. Coagulation efficiency was largely affected by pH, and the optimum pH's for cell recovery were about 4.6-5.6 for the Al-based coagulants and about 5-8 for the Fe-based coagulants. Ammonium ions that combined with metals to form complex compounds increased the coagulant requirement, and the additional requirement of coagulant was found to be proportional to the ammonium concentration. In addition, various ligands in addition to ammonium ions contained in the culture medium interfered with the coagulation reaction and increased the coagulant requirement also. The coagulant requirement increased with the cell concentration regardless of coagulant type. The polymeric coagulants such as PACS, Hi-PAX, and Ferix-3 were more effective than nonpolymeric coagulants of aluminum sulfate and ferrous sulfate. The optimum dosages of the coagulants tested were determined over a broad range of cell concentration of 20.5-210 g/L. It was observed that the energy requirement for centrifugation could be greatly reduced with cell coagulation.

Alcaligenes↗
PubMedDate not supplied

CT features of torsion of benign cystic teratoma of the ovary.

PURPOSE: The purpose of this work was to evaluate the usefulness of CT scans for distinguishing torsed from uncomplicated benign cystic teratoma (BCT). METHOD: Retrospective analysis was performed in 14 torsed BCTs (14 patients) and in 23 uncomplicated BCTs (20 patients) for comparison. The features on CT scans were compared to the pathologic findings. RESULTS: CT findings indicating torsed BCT were the presence of eccentric wall thickening of >1 cm, peritumoral infiltration, and presence of enlarged solid tubal mass adjacent to the uterus (p < 0.05). CONCLUSION: The present study suggests that CT is useful in differentiating torsed from uncomplicated BCT. Although CT findings are not specific for some patients, detection of certain CT findings could increase the diagnostic accuracy.

Adolescent↗
PubMedDate not supplied

Brenner tumor of the ovary: CT and MR findings.

PURPOSE: The purpose of this study was to determine the CT and MR characteristics of Brenner tumors, rare epithelial neoplasms of the ovary. METHOD: CT and MR scans of eight pathologically proven Brenner tumors of the ovary (seven benign, one malignant, and one associated with mucinous cystadenoma) were retrospectively reviewed. The masses were analyzed for location, size, external configuration, internal architecture, enhancement pattern, presence of calcification, and metastatic spread. RESULTS: The patients' median age was 63 years (range 39-79 years), and the mean size of the tumors was 11.4 cm (7.5-17 cm). All tumors were unilateral and had a well-defined margin. The mass was mostly solid in three, mostly cystic in one, and "mixed" solid and cystic in four cases. The tumors with cystic components (n = 5) were mostly multilocular in appearance (n = 4). All the solid components showed mild homogeneous enhancement on postcontrast CT and MRI. Extensive amorphous calcification within the solid component on CT was seen in five of six cases (83%). No characteristic findings discriminating malignancy from benign Brenner tumor could be found. CONCLUSION: Extensive amorphous calcification in a solid mass or solid component in a multilocular cystic mass is a characteristic finding of Brenner tumor of the ovary on CT and MRI.

Adult↗
PubMedDate not supplied

Radiological features of leiomyomatous tumors of the colon and rectum.

PURPOSE: The purpose of this study was to evaluate the radiological features of 12 pathologically proven cases of colorectal leiomyomatous tumors. METHOD: A retrospective analysis of radiologic findings was performed in 12 patients with pathologically proven colorectal leiomyomatous tumors (2 leiomyomas and 10 leiomyosarcomas). Available radiologic studies included abdominal CT scans in 11 patients, double contrast barium studies in 4, and pelvic MRI in 1. On imaging, we evaluated the size, tumor margin (smooth or lobulated), morphologic appearance, growth patterns (endocolic, exocolic, or combined), contrast enhancement patterns, presence or absence of calcification within the tumors, and metastasis. RESULTS: The involved tumor sites were the colon in 2 patients and the rectum in 10. The mean tumor size was 7.9 cm (range 2-15 cm): It was 3.5 cm in leiomyomas and 8.8 cm in leiomyosarcomas. On imaging studies, the tumor margin was smooth in three patients and lobulated in nine, with endocolic growth in one, exocolic in four, and combined in the remaining seven. Eight of the 12 tumors showed varying degrees of internal necrosis with heterogeneous contrast enhancement. Dystrophic calcification was noted in five patients. Metastasis was seen in the liver in three patients at the time of initial diagnosis, and lymphadenopathy was noted in two patients (paraaortic space in one and perirectal space in two). CONCLUSION: Although rare, the diagnosis of leiomyomatous tumor may be suggested especially when the tumor occurring in the colorectum shows exocolic growth or calcification with varying degree of internal necrosis.

Adolescent↗
PubMedDate not supplied

CT features of primary colorectal signet-ring cell carcinoma.

PURPOSE: The purpose of this work was to evaluate the CT features of 15 patients with primary colorectal signet-ring cell carcinomas. METHOD: We retrospectively reviewed the CT scans of 15 patients (mean age 44 years) with pathologically proved colorectal signet-ring cell carcinoma. On CT, we evaluated the site and length of the tumor, bowel wall thickening patterns, perirectal or pericolic infiltration, the presence or absence of colonic obstruction, and metastasis to other organs. RESULTS: The tumors were located in the rectum in nine patients, the sigmoid colon in one, the hepatic flexure in one, the transverse colon in one, the ascending colon in two, and the cecum in one. The tumor length ranged from 4.0 to 10.0 cm (mean 6.1 cm) with mean thickness of 2.1 cm. CT showed concentric bowel wall thickening in all patients ("even" in 8 and "uneven" in 7), target appearance was noted in 4, perirectal or pericolic infiltrations were moderate to severe in 12, and colorectal obstruction was seen in 6. In the tumor spread patterns, lymphadenopathy was noted in 13, invasion to adjacent pelvic organs in 5, peritoneal carcinomatosis in 4, liver metastasis in 2, and periureteric metastasis in 1. CONCLUSION: Primary signet-ring cell colorectal carcinoma should be included for differential consideration when CT shows a long length of concentric bowel wall thickening and target sign, especially when such findings occur in the rectum and in young patients.

Adolescent↗
PubMedDate not supplied

MR imaging of intersexuality.

Intersexuality involves an intermingling of the characteristics of each sex in varying degrees as a result of some flaw in embryonic development. Accurate demonstration of genital anatomy is essential for proper gender assignment and for treatment of intersexual disorders. Genital anatomy is well demonstrated with MR imaging, which offers unsurpassed soft-tissue contrast, multiplanar capability, and no radiation exposure. Intersexual disorders can be categorized into female pseudohermaphroditism, male pseudohermaphroditism, gonadal dysgenesis or agenesis, and true hermaphroditism. In female pseudohermaphroditism, MR images show normal internal female genitalia with masculinized external genitalia. In male pseudohermaphroditism, MR images show normal or mildly defective testes with incompletely masculinized external genitalia. In gonadal dysgenesis, combinations of normal, dysgenetic, and streak gonads are seen on MR images; in gonadal agenesis, no gonads are evident. In true hermaphroditism, both testicular and ovarian tissue is seen on MR images. MR imaging is essential for management of intersexual disorders.

Adult↗
PubMedDate not supplied

Radiologic findings of Behçet syndrome involving the gastrointestinal tract.

Behçet syndrome is characterized by the histopathologic finding of nonspecific vasculitis in multiple organs. The diagnosis is usually made on the basis of the combination of clinical signs and symptoms. This disease involves the gastrointestinal tract in 10%-50% of patients, and the terminal ileum and cecum are chiefly affected. Barium study is useful in demonstrating the characteristic radiographic features of Behçet syndrome involving the gastrointestinal tract. The presence of deep, penetrating ulcers results in a high rate of complications, such as perforation, fistula, hemorrhage, and peritonitis. Furthermore, recurrence of disease adjacent to or at the surgical anastomosis is common. Computed tomography is useful in determining the extent of the lesions and in identifying cases in which complications are likely to occur. Familiarity with the various radiologic findings of Behçet syndrome involving the gastrointestinal tract helps in making an early diagnosis, as well as in establishing an appropriate treatment strategy.

Abdominal Pain↗
PubMedDate not supplied

Ramosetron for the prevention of cisplatin-induced acute emesis: a prospective randomized comparison with granisetron.

Control of nausea and vomiting is very important in determining patient compliance with cisplatin chemotherapy. A multicentre, randomized, single-blind study was conducted to compare the tolerability and efficacy of ramosetron with those of granisetron over 24 h following cisplatin administration to cancer patients. In eight study centres, a total of 194 adult patients were randomly assigned to receive either intravenous ramosetron 0.3 mg or intravenous granisetron 3.0 mg. The anti-emetic effect of ramosetron determined from the no-vomiting rate lasted longer, but there was no significant difference in the number of acute vomiting episodes or the severity of nausea between the two groups. In the tolerability evaluation, there were no statistically significant differences between the two groups, except for a higher incidence of dull headache in the granisetron group. Ramosetron and granisetron appear to have equivalent efficacy and tolerability profiles, but the effects of ramosetron on the prevention of acute vomiting in patients undergoing cisplatin chemotherapy were longer lasting.

Adult↗
PubMedDate not supplied

Hydrogen sulfide effects on ammonia removal by a biofilter seeded with earthworm casts.

Ammonia (NH3) removal efficencies were evaluated when hydrogen sulfide (H2S) and NH3 in binary mixture gases were supplied to a ceramic biofilter seeded with earthworm (Lumbricus terrestris) casts. The effect of inlet H2S concentration and space velocity (SV) on the removal of NH3 was investigated after the acclimation of the biofilter with NH3 gas. When NH3 was singly supplied to the biofilter, NH3 removal was maintained at almost 100% until inlet NH3 concentration was increased up to 600 microL L(-1) and SV up to 330 h(-1), at which the elimination capacity of NH3 was 148 g N m(-3) h(-1). When H2S was supplied simultaneously, however, the accumulation of toxic sulfide ions showed dual effects on NH3 removal efficiencies. First, no effects were observed at inlet H2S loading below 60 g S m(-3) h(-1); however, inhibition by H2S at higher loading was observed above 60 g S m(-3) h(-1). The point at which loading achieved a maximum of more than 99% NH3 removal efficiency was 139 g N m(-3) h(-1), when inlet H2S concentration was held under 100 microL L(-1), but it dropped to 76 and 30 g N m(-3) h(-1) when the inlet H2S concentration increased to 220 and 460 microL L(-1), respectively. The critical points of inlet H2S loading that guaranteed over 99% NH3 removal were determined as 100, 100, 60, and 40 g S m(-3) h(-1) at inlet NH3 concentrations of 100, 200, 400, and 600 microL L(-1), respectively. Inlet NH3 loading had synergic effects of increasing the inhibition of inlet H2S loading on the NH3 removability of the biofilter.

Air Pollutants↗
PubMedDate not supplied

Leaching characteristics of heavy metals from sewage sludge by Acidithiobacillus thiooxidans MET.

An acidophilic, sulfur-oxidizing Acidithiobacillus thiooxidans MET bacterium was isolated from anaerobically digested, dewatered sewage sludge. This bacterium showed sulfur-oxidizing ability at both acidic and neutral conditions, and allowed metal leaching even at a high (130 g L(-1)) sludge solids concentration. We found that low metal leaching efficiency at high solids concentration was mainly due to an increase in buffering capacity resulting in retardation of pH reduction. Therefore, metal leaching was mainly influenced not by sludge solids concentration, but by the pH (or sulfate concentration per unit sludge mass) of the sludge solutions. The relationship between the pH of the sludge solution and the efficiency of metal leaching was obtained by quantitatively investigating the effect of pH reduction or the amount of sulfate produced per unit sludge mass on leaching of each metal. Furthermore, the relationship between total metal content in the sludge and metal leached to the solution was obtained for each metal. Such a relationship allowed estimation of leachable metal at various amounts of total metal content in sludge.

Gammaproteobacteria↗
PubMedDate not supplied

Prostate volume measurement by TRUS using heights obtained by transaxial and midsagittal scanning: comparison with specimen volume following radical prostatectomy.

OBJECTIVE: The purpose of this study was to determine, when measuring prostate volume by TRUS, whether height is more accurately determined by transaxial or midsagittal scanning. MATERIALS AND METHODS: Sixteen patients who between March 1995 and March 1998 underwent both preoperative TRUS and radical prostatectomy for prostate cancer were included in this study. Using prolate ellipse volume calculation (height x length x width x pi/6), TRUS prostate volume was determined, and was compared with the measured volume of the specimen. RESULTS: Prostate volume measured by TRUS, regardless of whether height was determined transaxially or midsagittally, correlated closely with real specimen volume. When height was measured in one of these planes, a paired t test revealed no significant difference between TRUS prostate volume and real specimen volume (p =.411 and p =.740, respectively), nor were there significant differences between the findings of transaxial and midsagittal scanning (p =.570). A paired sample test, however, indicated that TRUS prostate volumes determined transaxially showed a higher correlation coefficient (0.833) and a lower standard deviation (9.04) than those determined midsagittally (0.714 and 11.48, respectively). CONCLUSION: Prostate volume measured by TRUS closely correlates with real prostate volume. Furthermore, we suggest that when measuring prostate volume in this way, height is more accurately determined by transaxial than by midsagittal scanning.

Humans↗
PubMedDate not supplied

Granulosa cell tumor of scrotal tunics: a case report.

We report a case of adult granulosa cell tumor arising in the scrotal tunics. The patient was a 34-year-old man who presented with right scrotal swelling, first noticed four months previously. Under the initial clinical impression of epididymoorchitis, antibiotic treatment was instituted but there was no response. The paratesticular nodules revealed by ultrasound and magnetic resonance imaging mimicked intratesticular lesion, and radical orchiectomy was performed. Although several cases of adult testicular granulosa cell tumor, have been reported, the occurrence of this entity in the paratesticular area has not, as far as we are aware, been previously described.

Adult↗