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Biomedical subjects

G S Choi

Publications and source records attributed to G S Choi.

At least 19 recordsLinked to original sources
PubMed2006

Randomized clinical trial of splenectomy versus splenic preservation in patients with proximal gastric cancer.

BACKGROUND: Preservation or removal of the spleen during total gastrectomy for proximal gastric cancer is a matter of debate. METHODS: A randomized clinical trial included patients with gastric adenocarcinoma who underwent total gastrectomy either with (104 patients) or without (103) splenectomy. Postoperative outcome in the two groups was compared, including morbidity, mortality and survival. RESULTS: Gastrectomy combined with splenectomy tended to be associated with slightly higher morbidity and mortality rates, a slightly greater incidence of lymph node metastasis at the splenic hilum and along the splenic artery, and marginally better survival, but there were no statistically significant differences between the groups. Splenectomy had no impact on survival in patients with metastatic lymph nodes at the hilum of the spleen or in those with metastatic lymph nodes along the splenic artery. CONCLUSION: These results do not support the use of prophylactic splenectomy to remove macroscopically negative lymph nodes near the spleen in patients undergoing total gastrectomy for proximal gastric cancer.

Adenocarcinoma↗
PubMed2005

Plant uptake and downward migration of 85Sr and 137Cs after their deposition on to flooded rice fields: lysimeter experiments with and without the addition of KCl and lime.

In order to study the plant uptake and downward migration of radiostrontium and radiocesium deposited on to a flooded rice field, 85Sr and 137Cs were applied to the standing water over an acidic sandy soil in planted lysimeters. The plant uptake was quantified with the areal transfer factor (TFa, m2 kg(-1)-dry plant). Following the spiking 14 days after transplanting, the TFa values for the hulled seeds were 3.9 x 10(-4) for 85Sr and 1.4 x 10(-4) for 137Cs, whereas those for the straws were 1.3 x 10(-2) and 3.2 x 10(-4), respectively. The 137Cs TFa from the spiking at the anthesis/milky-ripe stage was several times higher than that from the earlier spiking, whereas the difference was much less in the 85Sr TFa. Such an increase in the 137Cs TFa was attributed mainly to an enhanced plant-base uptake. The addition of KCl and lime after the spiking significantly reduced the TFa values of both radionuclides. The reducing effect was greater for the later spiking. An appreciable fraction of the applied activity leached out of the lysimeter for 85Sr, whereas a negligible fraction leached for 137Cs. The leaching was remarkably increased by the KCl and lime addition for both. A conspicuous localization of 137Cs with respect to the soil surface was observed. In a batch experiment, the 137Cs concentration in the standing water decreased more rapidly than that of 85Sr, both of which were fitted to the power functions of the elapsed time. To add KCl and lime slowed such decreases to lessen the distribution coefficients (Kd) of both 85Sr and 137Cs.

Biological Transport↗
PubMed2004

Loss of CDX1 expression in colorectal carcinoma: promoter methylation, mutation, and loss of heterozygosity analyses of 37 cell lines.

Expression of the homeobox protein CDX1 is lost or reduced in a significant proportion of colorectal carcinomas (CRCs) but the underlying mechanism for this is unclear. We have demonstrated absence of CDX1 mRNA expression in 7 of 37 CRC cell lines and shown that all 7 cell lines have a methylated CDX1 promoter. Twenty-five cell lines showed both CDX1 mRNA expression and an unmethylated CDX1 promoter. The five remaining cell lines had a partially methylated CDX1 promoter and all expressed CDX1 mRNA; when treated with the demethylating agent, 5-aza-2'-deoxycytidine, these five cell lines all showed increased CDX1 expression. No mutations were found in the promoter and coding regions of CDX1. One polymorphism was demonstrated in each of the promoter, 5' UTR, and coding region of exon 1 of CDX1, but there were no associations between CDX1 mRNA expression and different polymorphic genotypes. Similarly, there was no association between CDX1 mRNA expression and loss of heterozygosity at the CDX1 locus. In conclusion, absence or reduction of CDX1 expression in CRC seems to be primarily regulated by promoter methylation and is probably selected for because of its impact on the differentiation of colonocytes.

Animals↗
PubMed2002

Modulation of natural killer cell activity affected by electroacupuncture through lateral hypothalamic area in rats.

Electroacupuncture (EA) has been reported to modulate natural killer cell (NK cell) activities. Also it is well known that hypothalamus directly mediates the effects of EA on analgesia. Especially lateral hypothalamic area (LHA) is related to splenic NK cell activities. In order to investigate the relationship between hypothalamus and effects of EA on NK cell activity, lesions have been made bilaterally at LHA of Spraque-Dawley rats. Subsequently, NK cell cytotoxities of normal and lesioned rats were measured with (51)Cr release immunoassay after EA stimulation for 2 and 14 days. NK cell activity of EA group was significantly higher than sham group. In addition, lesions abolished effects of EA on NK cell activity. These results strongly suggest that LHA is closely related to increase of NK cell activity induced by EA.

Animals↗
PubMed2001

Concentrations and activity ratios of uranium isotopes in the groundwater of the Okchun Belt in Korea.

Groundwater samples obtained from the Okchun Belt in Korea were separated into particulate and filtered fraction using a 0.45 microm membrane filter and concentrations and activity ratios of uranium isotopes in the fractions were determined by chemical separation and alpha-spectrometric measurements. Most of the uranium isotopes in the groundwater were found in the filtered water. Only less than 1% of the total uranium was detected in the particulate fraction. The concentrations and activity ratios of uranium isotopes in the groundwater measured in this study were variable, depending upon sampling site. Owing to a rapid material exchange between the subterranean hot waters and the rock strata, the concentrations of 238U in the groundwater in the hot spring area were found to be about four times higher than those elsewhere. Because of the alpha-particle recoil effect, the activity ratios of 234U/238U in the groundwater taken at "cold" spring sites were variable within the range 1.20 to 3.58, depending on the residence time of the groundwater. In the hot spring area, the activity ratios of 234U/238U were close to the equilibrium value (1.10 +/- 0.07) due to rapid erosion of the rock strata by the hot spring water.

Environmental Monitoring↗
PubMed2001

Simultaneous measurement of 89Sr and 90Sr in aqueous samples by liquid scintillation counting using the spectrum unfolding method.

Two radiostrontium isotopes, 89Sr and 90Sr, were measured simultaneously by liquid scintillation counter coupling with a full spectrum DPM counting protocol. Strontium was separated from the aqueous media by extraction chromatography using Sr-spec resin. Individual count rates were evaluated from quench correlation curves for 89Sr and 90Sr related with SIS and tSIE quench indicators. The method exhibited a counting efficiency of 95% for 89Sr and 92% for 90Sr within their full energy channels and gave highly precise results when the sample was counted within 4 h after strontium separation. Lower limits of detection were 37 mBq/l for 90Sr and 32 mBq/l for 89Sr with a 60 min counting time.

Journal Article↗
PubMed2000

Zucchini green mottle mosaic virus is a new tobamovirus; comparison of its coat protein gene with that of kyuri green mottle mosaic virus.

A novel virus we call zucchini green mottle mosaic virus (ZGMMV) was isolated from zucchini squash and its properties were determined. The size and shape of its virions, and other properties suggest that the virus is a tobamovirus. The coat protein (CP) genes of ZGMMV and kyuri green mottle mosaic virus (KGMMV), which also infects zucchini squash plants, were cloned and their nucleotides sequences were determined. The CP genes of ZGMMV and KGMMV are composed of 161 amino acid residues, and they share 77.6% amino acid identity. Western blot analysis showed that the two viruses are serologically related but not identical. Comparison of the sequences with those of sixteen other tobamoviruses revealed that the two viruses had much higher identity to cucumber green mottle mosaic virus (CGMMV), another tobamovirus infectious to cucurbit plants, than other tobamoviruses. The nucleotide and amino acid sequences of ZGMMV were from 29.5 to 78.4% and from 29.3 to 77.6% identical, respectively, to those of other tobamoviruses. The predicted virion assembly origins of the two tobamoviruses were located in the CP region of the genomic RNAs, and the predicted secondary structures were more similar to that of CGMMV than those of other tobamoviruses. The seventeen tobamo-viruses could be classified into three main subgroups based on the phylogenetic tree analysis on the CP gene, and ZGMMV and KGMMV formed a third subgroup together with CGMMV and sunn-hemp mosaic virus (SHMV). These results show that ZGMMV is a previously unknown member of the Tobamovirus genus.

Base Sequence↗
PubMed2000

Osteoma cutis coexisting with cutis laxa-like pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE) is a heritable disorder of elastic fibers characterized by yellowish, coalescing papules on the loose and wrinkled flexural area. There have been no reports of osteoma cutis associated with PXE. A 17-year-old Korean girl presented cutis laxa-like marked wrinkling on the flexural area, and a skin biopsy specimen revealed multiple foci of ossification with irregularly clumped, basophilic-stained elastic fibers in the reticular dermis and calcium deposits along the elastic fibers. Ultrasonographic evaluation showed multiple tiny osteomas diffusely scattered along the entire abdominal wall, axillae, and medial aspect of the upper arms. We report the first case of osteoma cutis coexisting with cutis laxa-like PXE.

Adolescent↗
PubMed2000

Analysis of methods for the generation of dendritic cells from human peripheral blood monocytes.

Dendritic cells (DC) are highly efficient antigen-presenting cells that initiate the primary immune response. Several laboratories have developed culture systems for human DC from peripheral blood monocytes. Most of these studies have used fetal calf serum (FCS) containing culture conditions that are inappropriate for human application. GM-CSF and IL-4 were used to make immature DC. The monocyte-conditioned medium (MCM) was used to induce the final maturation of DC. Using the previously described methods, the quality of MCM has unpredictable variations. Therefore using a defined cocktail of growth factors for the generation of mature DC would be advantageous for experimental as well as clinical purposes. In this study, it is suggested that combinations of both GM-CSF/IL-4 or GM-CSF/IL-13 could be used as the first-step culture to produce immature DC, and that cytokine cocktail (GM-CSF, IL-4, IL-1beta, TNF-alpha, IL-6, PGE2) was as efficient as MCM for the second step-culture to produce fully maturated DC. Here, we have generated an easily reproducible culture system for DC that allows for the generation of large amounts of immature and mature DC, and we also now have established the method in a FCS-free system that is suitable for clinical use.

Cell Division↗
PubMed2000

Squamous cell lung cancer with solitary subungual metastasis.

Subungual metastasis resulting from internal malignancies is an extremely rare event. A few cases of subungual metastasis from lung cancer have been reported. However, subungual metastasis arising from lung cancer without any other form of distant metastases has not been reported. The misdiagnosis of a solitary subungual metastases as a benign inflammatory lesion is an important problem as it may cause the misdiagnosis of a lower stage of lung cancer. We may be reporting the first case of a subungual metastasis from lung cancer without any other distant metastases.

Carcinoma, Squamous Cell↗
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↗
PubMed1999

Anocutaneous advancement flap closure of high anal fistulas.

BACKGROUND: Fistula-in-ano may be treated by closing the internal fistulous opening. An anocutaneous flap was developed to facilitate this closure. METHODS: From October 1995 to April 1997, 40 patients with high trans-sphincteric or suprasphincteric anal fistulas were treated. The important components of the procedure are excision of the internal opening, excision or curettage of the tract, closure of the internal opening by an anocutaneous flap, and external drainage. RESULTS: In two patients (5 per cent) the flap separated and the sutured internal opening was exposed. One of the two was healed 4 weeks later. In the remaining 38 patients, complete healing occurred 2-3 weeks after operation. No patient was incontinent of gas or stool. CONCLUSION: This procedure is technically simple, heals rapidly with minimal scarring, and cures anal fistulas while preserving the anal sphincter.

Adult↗
PubMed1999

Treatment of Ota's nevus by Q-switched alexandrite laser : therapeutic outcome in relation to clinical and histopathological findings.

Ota's nevus is a dermal melanocytic disease which causes serious cosmetic problems for affected individuals. Recently Q-switched lasers with a pulse duration of 100 nsec or less became available for patient treatment. We evaluated the clinical efficacy of the Q-switched alexandrite laser (755 nm, 100 nsec) in relation to the histopathological findings. Fifty-five Korean patients with Ota's nevus were treated with a Q-switched alexandrite laser for three sessions (7.5 J/cm2) at three month intervals. Skin biopsies were taken in all of the patients before treatment and immediately after treatment in five patients. Clinical effectiveness and side effects were evaluated by direct observation and photographs. Pigment clearing was excellent in 27 patients (49%), good in 17 patients (31%), fair in 7 patients (13%) and poor in 4 (7%) patients. Postinflammatory hyperpigmentation developed in 30 patients (55%) which resolved within four months. But there were no serious complications including scarring or textural change. The therapeutic outcome was not affected by color but by depth of the nevus. Nevi of Ota with depth of 1 mm or less were associated with excellent or good results. Q-switched alexandrite laser is a very effective and safe tool for treating Ota's nevus. Depth of 1 mm or less of dermal melanocytes was a good prognostic marker.

Adolescent↗
PubMed1998

A glutamate to lysine mutation at the end of 2B rod domain of keratin 2e gene in ichthyosis bullosa of Siemens.

Ichthyosis bullosa of Siemens is a rare autosomal dominant skin disorder whose clinical findings are quite similar to those of epidermolytic hyperkeratosis. The differences between those two diseases include absence of erythroderma and different distributions in the skin in ichthyosis bullosa of Siemens. Recent studies have confirmed that ichthyosis bullosa of Siemens is caused by the mutation in the keratin 2e (K2e) gene, which is expressed in the upper spinous and granular layers. We have identified a sporadic case of ichthyosis bullosa of Siemens; based on diagnosis by histopathological findings, the K2e gene of the patient was analysed. Direct sequencing of PCR products revealed a single base change in sequences encoding the highly conserved end of the 2B rod domain segment of the K2e gene. This mutation results in substitution of the codon for glutamic acid by a codon for lysine in position 493 in K2e (E493K). Mutations of the K2e gene involving five different residue positions (Q187P, T485P, L490P, E493D, E493K and E494K) are known to cause ichthyosis bullosa of Siemens. Of these sites, E493, which is conserved in type I and type II keratin genes, is the most frequently altered amino acid in the K2e gene. These data together suggest that this codon constitutes a hot spot for mutations in the K2e gene.

Amino Acid Substitution↗
PubMed1998

Epidermolysis bullosa acquisita localized to the face.

A 39-year-old woman had a three-year history of recurrent bullous eruption localized to her left cheek. The diagnosis of epidermolysis bullosa acquisita was confirmed by means of direct immunofluorescence and direct immunoelectron microscopic studies performed on the perilesional salt-split skin. Topical corticosteroid treatment reduced pruritus and bullae formation. This case of localized epidermolysis bullosa acquisita on the face is reminiscent of Brunsting-Perry cicatricial pemphigoid. We also review the previously reported cases of localized epidermolysis bullosa acquisita.

Administration, Topical↗
PubMed1997

Comparison of five systems for staging lymph node metastasis in gastric cancer.

BACKGROUND: There are several systems for staging lymph node metastasis in gastric cancer. Their relative merits are not clear. METHODS: In this retrospective analysis, the nodal status was classified according to the Union Internacional Contra la Cancrum (UICC) and Japanese staging systems, the number and frequency of lymph node metastasis, and the level of involved nodes. Each staging system was scored as good (+1), fair (0) or poor (-1) with respect to prognostic value, theoretical value, convenience, reproducibility and surgical applicability. RESULTS: There were no differences between the five staging systems in predicting survival. The Japanese staging system was most arbitrary owing to the complexity of the system, although it had an advantage in surgical application. The same disadvantage was found in the UICC system and the level system. Determination of the number and frequency of involved nodes was convenient and reproducible, but the number of lymph nodes dissected must be considered when the number of positive nodes is used for staging. CONCLUSION: The classification of metastasis to the regional lymph nodes as N0 (no nodal metastasis), N1 (metastasis in 1-25 per cent of dissected nodes) and N2 (metastasis in more than 25 per cent of dissected nodes) would be a simple, convenient, reproducible staging system with an ability to predict surgical results.

Humans↗
PubMed1995

Extensive aberrant Mongolian spot.

A 9-month-old male infant had generalized diffuse blue-gray pigmentation over most of his body, sparing the scalp, face, neck, palms, soles, periumbilical area, genital area, and nipples. Within the lesion, there were several conspicuous macules of considerably darker hue. Histologic examination revealed numerous dermal melanocytes. By 16 months of age, the child's blue-gray pigmentation had decreased substantially.

Biopsy↗