Biomedical subjects

D Y Kim

Publications and source records attributed to D Y Kim.

At least 145 records · Page 8Linked to original sources

PubMed2000

Expression of cyclins in ductal hyperplasia, atypical ductal hyperplasia and ductal carcinoma in situ of the breast.

Cyclin/cdc complexes are known to function in cell-cycle regulation. Cyclin D1/cdk4 and -6 complexes, which functions as a G1-S checkpoint and cyclin B1/cdc2 complexes, a G2-M checkpoint are essential for DNA synthesis and mitosis, respectively. Thus, dysregulated overexpression of cyclins appears to be involved in uncontrollable cell proliferation and early tumor development. We investigated the expression and proliferative index of cyclin D1 (PIcyclin D1), cyclin B1 (PIcyclin B1) and Ki-67 (PIKi-67) using immunohistochemical staining on 15 cases of ductal hyperplasia (DH), 26 cases of atypical ductal hyperplasia (ADH) and 43 cases of ductal carcinoma in situ (DCIS) of the breast in order to evaluate whether these cyclins are associated with abnormal cell proliferation and play a role in tumor development from ADH to carcinoma. Furthermore, we investigated whether the expression and proliferative index of the cyclins and Ki-67 are correlated with the histologic grade according to the Van Nuys classification and with the histologic subtype according to traditional classification. Finally, we estimated the correlation coefficient among PIcyclin D1, PIcyclin B1, PIKi-67 and estrogen receptor in ADH and DCIS. The expression of cyclin D1 was detected in 39.5% of DCIS and 7.7% of ADH cases. In the DH cases, expression of cyclin D1 was not found. Expression of cyclin B1 was also detected in 69.7% of DCIS, 50.0% of ADH and 93.3% of the DH cases. The PIcyclin D1 was significantly different among these three groups. Moreover, the PIcyclin D1 and PIKi-67 were differed significantly between the low grade DCIS and ADH cases. However, PIcyclin B1 only appeared to be significantly different between the total DCIS and ADH. Results of the correlation coefficient among PIcyclin D1, PIcyclin B1 and PIKi-67 were positively correlated with each other. No significant correlation was found between the expression of ER and cyclin D1 in ADH and DCIS. In summary, our results support the hypothesis that a cyclin D1 and cyclin B1 protein aberration, along with Ki-67, may act as a relatively early event in the tumor development from ADH to carcinoma.

Breast↗

PubMed2000

Prosthetic ambulation in a paraplegic patient with a transfemoral amputation and radial nerve palsy.

Great importance and caution should be placed on prosthetic fitting for a paraplegic patient with an anesthetic residual limb if functional ambulation is to be achieved. The combination of paraplegia with a transfemoral amputation and radial nerve palsy is a complex injury that makes the rehabilitation process difficult. This article describes a case of L2 paraplegia with a transfemoral amputation and radial nerve palsy on the right side. Following the rehabilitation course, the patient independently walked using a walker at indoor level with a transfemoral prosthesis with ischial containment socket, polycentric knee assembly, endoskeletal shank and multiaxis foot assembly and a knee ankle foot orthosis on the sound side. The difficulties of fitting a functional prosthesis to an insensate limb and the rehabilitation stages leading to functional ambulation are reviewed.

Adult↗

PubMed2000

Development of a speciated, hourly, and gridded air pollutants emission modeling system--a case study on the precursors of photochemical smog in the Seoul metropolitan area, Korea.

A speciated, hourly, and gridded air pollutants emission modeling system (SHEMS) was developed and applied in predicting hourly nitrogen dioxide (NO2) and ozone (O3) levels in the Seoul Metropolitan Area (SMA). The primary goal of the SHEMS was to produce a systemized emission inventory for air pollutants including ozone precursors for modeling air quality in urban areas. The SHEMS is principally composed of three parts: (1) a pre-processor to process emission factors, activity levels, and spatial and temporal information using a geographical information system; (2) an emission model for each source type; and (3) a post-processor to produce report and input data for air quality models through database modeling. The source categories in SHEMS are point, area, mobile, natural, and other sources such as fugitive emissions. The emission database produced by SHEMS contains 22 inventoried compounds: sulfur dioxide, NO2, carbon monoxide, and 19 speciated volatile organic compounds. To validate SHEMS, the emission data were tested with the Urban Airshed Model to predict NO2 and O3 concentrations in the SMA during selected episode days in 1994. The results turned out to be reliable in describing temporal variation and spatial distribution of those pollutants.

Air Pollutants↗

PubMed2000

Overexpression of cyclin D1 and cyclin E in 1,2-dimethylhydrazine dihydrochloride-induced rat colon carcinogenesis.

Deregulation of G1 cyclins has been reported in several human and rodent tumors including colon cancer. To investigate the expression pattern of G1 cyclins in 1,2- dimethyl-hydrazine dihydrochloride (DMH)-induced rat colon carcinogenesis, we studied the expression of cyclin D1 and cyclin E by quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis and immunohistochemistry (IHC). The mRNA level of cyclin D1 was increased 1.2-fold in adenocarcinomas but not significantly in adenomas, when compared with normal rat colonic mucosa (p<0.05). The cyclin E mRNA level was increased 2.7-fold in adenomas and 3.3-fold in adenocarcinomas (p<0.05). The PCNA mRNA level was also increased 1.9-fold in adenomas and 1.8-fold in adenocarcinomas (p<0.05). Immunohistochemical staining revealed exclusive nuclear staining of the neoplastic cells for cyclin D1, cyclin E and PCNA. Cyclin D1 expression was detected in 56.3% of the adenomas and in 61.5% of the adenocarcinomas examined, whereas cyclin E expression was detected in 87.5% of the adenomas and in 92.3% of the adenocarcinomas. Overall, cyclin D1, cyclin E and PCNA expression was significantly increased at both the mRNA and protein levels in normal colonic mucosa, adenomas and adenocarcinomas, but there was no significant difference in the degree of expression of these genes in adenomas and adenocarcinomas. Our results indicate that the overexpression of cyclin D1 and cyclin E may play an important role during the multistage process of rat colon carcinogenesis, at a relatively early stage, and may disturb cell-cycle control in benign adenomas, and thereafter, participate in tumor progression.

1,2-Dimethylhydrazine↗

PubMed1999

Electrophysiological evidence for the role of substance P in retinohypothalamic transmission in the rat.

The retinohypothalamic tract (RHT) is a neural pathway through which photic time cues are delivered directly to the mammalian circadian pacemaker in the suprachiasmatic nucleus (SCN). Although the excitatory amino acid glutamate is the primary neurotransmitter in the RHT, other substances such as substance P (SPq also have been suggested to play a role. The present study tested the hypothesis that SP participates in retinohypothalamic transmission and selectively modulates either N-methyl-D-aspartate (NMDA) or non-NMDA receptor-mediated neurotransmission. The SP antagonist L-703,606 depressed the excitatory postsynaptic current (EPSC) evoked by optic nerve stimulation in SCN neurons in rat hypothalamic slices. The SP antagonist also had a similar depressive effect on the NMDA and non-NMDA receptor-mediated components of the EPSC. These results suggest that SP is an excitatory neuromodulator contributing to the expression of both the NMDA and non-NMDA receptor-mediated components of retinohypothalamic transmission.

2-Amino-5-phosphonovalerate↗

PubMed1999

Effect of specific production rate of recombinant protein on multimerization of plasmid vector and gene expression level.

In fed-batch cultures of recombinant Escherichia coli BL21(DE3)[pT7-G3IL2] at high cell concentration, the post-induction specific growth rate was carefully regulated by controlled medium feed to maximize the synthesis level of recombinant fusion interleukin-2, G3.IL-2. A maximum concentration of G3.IL-2 (11.25 g l(-1)) was achieved in the induced recombinant culture growing at the rate of 0.056 h(-1). A steep decrease in the expression level of G3.IL-2 was observed at the post-induction specific growth rates higher than its optimal value (0.056 h(-1)). In the induced recombinant cultures, plasmid multimerization was observed and highly dependent on specific growth and production rate: a higher post-induction specific growth rate and an increased specific production rate tended to significantly promote it much further. Moreover, plasmid stability was found to decrease rapidly in a faster growing culture.

Escherichia coli↗

PubMed1999

Immunohistochemical detection of oxidative DNA damage induced by ischemia-reperfusion insults in gerbil hippocampus in vivo.

There is much evidence to suggest that ischemic injury occurs during the reperfusion phase of ischemia-reperfusion insults, and that the injury may be due to reactive-oxygen-species (ROS)-mediated oxidative events, including lipid peroxidation and DNA damage. However, oxidative DNA damage has until now not been examined in situ. In the present study, we report for the first time observation of cell type- and region-specific oxidative DNA damages in 5 min transient ischemic model by immunohistochemical methods, using monoclonal antibody against 8-hydroxy-2'-deoxyguanosine (8-OHdG), an oxidative DNA product. The cell types containing 8-OHdG immunoreactivity were neurons, glia and endothelial cells in the hippocampus. The 8-OHdG immunoreactivity was present in the nucleus but not the cytoplasm of these cells. The level of 8-OHdG in CA1 increased significantly (P<0.05) at the end of 30 min after ischemia, but there was no increase within CA2 and CA3 areas. The 8-OHdG levels in the hippocampus increased significantly (about fourfold) after 3 h of reperfusion and remained significantly (P<0.01) elevated for at least 12 h. At 4 days after ischemia, 8-OHdG levels in the CA2 and CA3 areas decreased to levels of the sham without neuronal loss, while disappearance of 8-OHdG immunoreactivity in the CA1 coincided with neuronal death in this area. These findings strongly suggest that ischemia-induced DNA damage evolves temporally and spatially, and that oxidative DNA damage may be involved in delayed neuronal death in the CA1 region.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed1999

Design and development of new collimator cones for fractionated stereotactic radiation therapy in Samsung Medical Center.

PURPOSE: In stereotactic radiotherapy using X-Knife system, the commercially supplied collimator cone system had a few mechanical limitations. The authors have developed new collimator cones to overcome these limitations and named them "SMC type" collimator cones. METHODS: We made use of cadmium-free cerrobend alloy within the stainless steel cylinder housing. We made nine cones of relatively larger sizes (3.0 cm to 7.0 cm in diameter) and of shorter length with bigger clearance from the isocenter than the commercial cones. The cone housing and the collimator cones were designed to insert into the wedge mount of the gantry head to enable double-exposure linac-gram taking. RESULTS: The mechanical accuracy of pointing to the isocenter was tested by ball test and cone rotation test, and the dosimetric measurements were performed, all of which were with satisfactory results. A new innovative quality assurance procedure using linac-grams on the patients at the actual treatment setup was attempted after taking 10 sets of AP and lateral linac-grams and the overall mechanical isocenter accuracy was excellent (average error = 0.4 +/- 0.2 mm). CONCLUSIONS: We have developed the SMC type collimator cone system mainly for fractionated stereotactic radiation therapy use with our innovative ideas. The new cones' mechanical accuracy and physical properties were satisfactory for clinical use, and the verification of the isocenter accuracy on the actual treatment setup has become possible.

Alloys↗

PubMed1999

Gating connexin 43 channels reconstituted in lipid vesicles by mitogen-activated protein kinase phosphorylation.

The regulation of gap junctional permeability by phosphorylation was examined in a model system in which connexin 43 (Cx43) gap junction hemichannels were reconstituted in lipid vesicles. Cx43 was immunoaffinity-purified from rat brain, and Cx43 channels were reconstituted into unilamellar phospholipid liposomes. The activities of the reconstituted channels were measured by monitoring liposome permeability. Liposomes containing the Cx43 protein were fractionated on the basis of permeability to sucrose using sedimentation in an iso-osmolar density gradient. The gradient allowed separation of the sucrose-permeable and -impermeable liposomes. Liposomes that were permeable to sucrose were also permeable to the communicating dye molecule lucifer yellow. Permeability, and therefore activity of the reconstituted Cx43 channels, were directly dependent on the state of Cx43 phosphorylation. The permeability of liposomes containing Cx43 channels was increased by treatment of liposomes with calf intestinal phosphatase. Moreover, liposomes formed with Cx43 that had been dephosphorylated by calf intestinal phosphatase treatment showed increased permeability to sucrose. The role of phosphorylation in the gating mechanism of Cx43 channels was supported further by the observation that phosphorylation of Cx43 by mitogen-activated protein kinase reversibly reduced the permeability of liposomes containing dephosphorylated Cx43. Our results show a direct correlation between gap junctional permeability and the phosphorylation state of Cx43.

Amino Acid Sequence↗

PubMed1999

Fractionated stereotactic radiation therapy for locally recurrent nasopharynx cancer: report of three cases.

BACKGROUND: This article reports on experience with fractionated stereotactic radiation therapy (FSRT) for locally recurrent nasopharynx cancer. METHODS: Three patients with locally recurrent nasopharynx cancer were given FSRT as reirradiation between September 1995 and August 1996. Application of FSRT was the third radiation therapy in two patients. Authors used the individually made relocatable Gill-Thomas-Cosman (GTC) stereotactic frame, and the radiation dose planning was performed using XKnife-3. The total doses to the recurrent tumor were 45 Gy/18 fractions in two patients, who were given concurrent chemotherapy as a radiosensitizer, and 50 Gy/20 fractions in the other patient. In all three patients the dose per fraction was 2.5 Gy, and the fraction schedule was to give five daily treatments per week. RESULTS: Authors observed satisfactory symptomatic improvement and remarkable objective tumor size decrease through the magnetic resonance (MR) images taken one month post-FSRT in all three patients. No neurological side effect was observed. All three patients died with regional and distant seeding outside the FSRT field at seven, nine, and nine months, respectively. CONCLUSION: FSRT as reirradiation for locally recurrent nasopharynx cancer seemed to be effective and safe.

Carcinoma↗

PubMed1999

Expression and characterization of the HMG-CoA reductase of the thermophilic archaeon Sulfolobus solfataricus.

The thermostable class I HMG-CoA reductase of Sulfolobus solfataricus offers potential for industrial applications and for the initiation of crystallization trials of a biosynthetic HMG-CoA reductase. However, of the 15 arginine codons of the hmgA gene that encodes S. solfataricus HMG-CoA reductase, 14 (93%) are AGA or AGG, the arginine codons used least frequently by Escherichia coli. The presence of these rare codons in tandem or in the first 20 codons of a gene can complicate expression of that gene in E. coli. Problems include premature chain termination and misincorporation of lysine for arginine. We therefore sought to improve the expression and subsequent yield of S. solfataricus HMG-CoA reductase by expanding the pool size of tRNA(AGA,AGG), the tRNA that recognizes these two rare codons. Coexpression of the S. solfataricus hmgA gene with the argU gene that encodes tRNA(AGA,AGG) resulted in an over 10-fold increase in enzyme yield. This has provided significantly greater quantities of purified enzyme for potential industrial applications and for crystallographic characterization of a stable class I HMG-CoA reductase. It has, in addition, facilitated determination of kinetic parameters and of pH optima for all four catalyzed reactions, for determination of the K(i) for inhibition by the statin drug mevinolin, and for comparison of the properties of the HMG-CoA reductase of this thermophilic archaeon to those of other class I HMG-CoA reductases.

Acyl Coenzyme A↗

PubMed1999

Identification of IY81149 and its metabolites in the rat plasma using the on-line HPLC/ESI mass spectrometry.

Reversed-phase high-performance liquid chromatography/mass spectrometry (HPLC/MS) with an electrospray ionization (ESI) interface was applied to the identification of metabolites of IY 81149 in the rat plasma. Fragments obtained using collision-induced dissociation (CID) in both positive and negative modes were utilized to elucidate the structure of metabolites. The eluent from the conventional HPLC column was split and directly introduced into an ESI-mass spectrometer for the identification of the structures. The CID technique allowed the sensitive identification of sulfonyl-IY81149 and hydroxy-IY81149 from the rat plasma.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed1999

Solid and papillary epithelial neoplasm of the pancreas in children.

Solid and papillary epithelial neoplasm of the pancreas is an uncommon low-grade malignant tumor found predominantly in young females. In this paper, the authors report the tumor's clinical characteristics and the results of surgery in six children. Six cases of solid and papillary epithelial neoplasm of the pancreas pathologically verified at Seoul National University Children's Hospital between 1985 and 1997 were retrospectively analyzed. Four were girls and two were boys, and their mean age at surgery was 11.2 years (range 8-13 years). All patients presented with an abdominal mass and tumor ranging in size from 6.5 x 6.0 cm to 10.5 x 8.0 cm. Five were located in the head and one in the tail of the pancreas; exploration showed that no case involved local invasion or metastasis. All patients underwent complete resection, which involved five pancreaticoduodenectomies and one distal pancreatectomy. No patient died during surgery, and after a mean follow-up period of 5.5 years (range 1.5-12.5 years) all were alive with no recurrences. We believe that the malignancy of this tumor is low grade and that the prognosis is good. For a neoplasm arising anywhere in the pancreas, complete resection is the treatment of choice. Solid and papillary epithelial neoplasm of the pancreas of children shows less female preponderance in children than in adults.

Adolescent↗

PubMed1999

Telomerase RNA expression during progression of gastric cancer.

Telomerase, an enzyme associated with cellular immortality and malignancy, is stringently repressed in most normal somatic cells but is reactivated in malignant tumor cells and immortal cell lines, indicating that activation of telomerase may play an important role in tumorigenesis and immortalization. The pattern of human telomerase RNA (hTR) expression during progression of gastric cancer was investigated by a radioactive in situ hybridization (ISH) assay. Paraffin-embedded sections of 85 archival samples from Korean patients with benign and various malignant stages of gastric carcinomas as well as normal and regenerative tissues were studied. In normal gastric mucosae and regenerative lesions such as chronic peptic ulcer and hyperplastic polyps, only a weak degree of hTR expression was noted, and the expression was limited to basal cells of the gastric glands. Also, a moderate degree of hTR expression was present in the germinal centers of lymphoid follicles present in the submucosa. In tubular adenomas, the degree of hTR expression was also generally weak, but, unlike normal gastric mucosa, the expression was rather diffuse and occasionally focal in distribution. However, moderate to intense and usually diffuse hTR expression was present in all cancerous tissues at different stages. Although some heterogeneity of hTR expression was noted, there was a tendency for intensity of hTR expression to increase gradually as the cancer progressed to a more advanced stage. Our results indicate that upregulation of telomerase expression is associated with gastric cancer development or plays some role in gastric carcinogenesis. Upregulation of hTR expression detected by ISH assay may be a useful marker or tool for the early detection of gastric cancer.

Adenoma↗

PubMed1999

Mutations in hMSH6 alone are not sufficient to cause the microsatellite instability in colorectal cancer cell lines.

Microsatellite instability (MSI) at simple repeated sequences characterises a distinct mechanism of carcinogenesis in hereditary nonpolyposis colorectal cancer (HNPCC), as well as sporadic colorectal cancers displaying MSI. Such MSI is associated with mutations of hMSH2 and hMLH1, and somatic frameshift mutations in TGF-beta RII, IGFIIR, BAX, hMSH3 and hMSH6 at simple repeated sequences in coding regions. The aim of this study was to look for a correlation between mutations in mismatch repair genes and frameshift mutations in colorectal cancer cell lines with MSI. Using 22 colorectal cancer cell lines, we examined the MSI status at mononucleotide repeat microsatellite markers and mutations in hMSH2 and hMLH1, TGF-beta RII, IGFIIR, BAX, hMSH3 and hMSH6. Thirteen of 22 lines (59%) displayed MSI. In these 13 lines showing MSI, 10 lines (77%) had mutations in TGF-beta RII, nine lines (69%) in BAX, seven lines (54%) in hMSH6, and six lines (46%) in hMSH3, while mutations in the IGFIIR gene were identified in only two lines (15%). Of the 13 lines with MSI, six lines (46%) harboured mutations/deletions in hMSH2 (two nonsense mutations, three deletions and one no expression of transcripts) and three of these cell lines (50%) had mutations both in the hMSH2 and hMSH3 genes. Two cell lines (15%) had mutations/deletions in hMLH1 (one missense mutation and one deletion) and these two cell lines also had mutations in hMSH3. One line had a mutation in hMSH3 only, although this line showed MSI and had mutations in TGF-beta RII, IGFIIR and BAX. All lines with mutations in hMLH1, hMSH2, TGF-beta RII, IGFIIR, BAX and hMSH3 genes showed MSI. However, of the nine lines without MSI, two (22%) had homozygous mutations in hMSH6. In these two cell lines, no mutations were identified in hMLH1, hMSH2, TGF-beta RII, IGFIIR, BAX and hMSH3. Our results indicate that mutations in hMLH1, hMSH2 and hMSH3 are associated with MSI, but mutations in hMSH6 are not. We conclude that mutations in hMSH6 alone are not sufficient to cause MSI, although protein functional effects of these mutations should still be examined.

Base Pair Mismatch↗

PubMed1999

Sequential segmental approach to fetal congenital heart disease.

The sequential segmental approach is now universally used in the diagnosis of congenital heart disease. Its utilization during fetal sonography has not been well described. In this review, we show how the fetal heart can be approached in a sequential segmental manner by using six basic sonographic views. The transverse view of the fetal upper abdomen is obtained to determine the arrangement of the abdominal organs, which, in most cases, provides the important clues to the determination of the atrial arrangement. The four-chamber view is obtained to evaluate the atrioventricular junctions. The views of the left and right ventricular outflow tracts are obtained to evaluate the ventriculoarterial junctions. The three-vessel view and the aortic arch view are obtained for the evaluation of the arrangement and size of the great arteries, which provides the additional clues to the diagnosis of the abnormalities involving the ventriculoarterial junctions and the great arteries. The standard protocol to acquire these six basic views is also introduced.

Echocardiography↗

PubMed1999

Canine distemper virus infection in binturongs (Arctictis binturong).

Two binturongs (Arctictis binturong) kept in outdoor exhibits at Everland Zoological Gardens in Korea died within 10 days of the onset of clinical signs that included depression, dyspnoea, diarrhoea and convulsions. On necropsy, the significant gross findings were limited to the lungs and the gastrointestinal tract. Proteus vulgaris was isolated from the lung of one animal. Histopathologically, diffuse severe bronchointerstitial pneumonia with secondary bacterial infection was noted in the lungs. Intracytoplasmic eosinophilic inclusion bodies were seen in the lining epithelium of the bronchi, bronchioles, small and large intestines, renal pelvis and urinary bladder. Canine distemper virus (CDV)-specific antigens were demonstrated in frozen sections of the lungs by the direct immunofluorescence technique. This is believed to be the first confirmed report of CDV infection in binturongs.

Animals↗

PubMed1999

Surgical correction of cryptotia using Medpor.

Cryptotia is a congenital auricular anomaly found more commonly in Orientals than whites. The characteristics of cryptotia are the invagination of the upper part of the auricle under the temporal skin and the deformity of the auricular cartilage. The goals of the repair of cryptotia are to release the upper ear from the side of the head to restore the retroauricular groove, to correct the malposition, and to correct the cartilaginous deformity. To lengthen the skin between the superior portion of the auricle and the scalp, the authors used both the modified Z-plasty and the temporal advancement flap. We partially detached the abnormal insertion of the superior auricular muscle at the upper part of the helix to make it weak. After complete exposure of the posterior aspect of the upper auricular cartilage, the constricted intrinsic transverse and oblique muscles were cut, and everting horizontal mattress sutures were inserted on the antihelix to expand the constricted body and crus of the antihelix. Thereafter, an ultrathin Medpor sheet (0.85-mm thickness) was fixed with 6-0 nylon sutures to the posterior aspect of the corrected antihelical cartilage for lengthening and splinting the relatively shortened upper pole of the deformed cartilage. This operative method is thought to be useful in maintaining the lengthened auricular height and shape, and in preventing the relapse of ear cartilage deformities.

Adolescent↗