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Biomedical subjects

K S Cho

Publications and source records attributed to K S Cho.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effects of pretreatment clinical parameters on bioactive glass implantation in intrabony periodontal defects.

BACKGROUND: The various methods for regeneration of periodontal tissue that have been developed can be classified into guided tissue regeneration and bone implantation. Since the implantation materials have shown both deficiencies and merits, dentists have begun exploring the bioactive glass first used in plastic surgery. This paper examines the effectiveness of this new material on periodontal intrabony defects. METHODS: Clinical effects of bioactive glass implantation in intrabony periodontal defects were evaluated 6 months after surgery in 38 intrabony defects from 38 patients with chronic periodontitis. Twenty-one experimental defects received bioactive glass implantation (test group), while 17 control defects were treated with a flap procedure only (control group). The criteria for comparative observation were preoperative and postoperative probing depth (PD), clinical attachment level (CAL), bone probing depth (BPD), and gingival recession. RESULTS: Reductions in PD were observed in both groups (P<0.01). The reduction in PD was significantly greater in the test group when preoperative PD exceeded 7 mm (P<0.01). Improvements in CAL were also observed in both groups (P<0.01), with the test group showing significantly greater gains (P<0.05). In those cases where preoperative CAL was less than 7 mm, there was no statistically significant difference between the two groups. Reduction in BPD was observed in both groups, with the test group showing significantly greater reduction (P <0.01). There was no significant difference in BPD change, however, when preoperative BPD was < or =7 mm. Significantly greater reduction of BPD in the test group was observed when intrabony defect depth was >4 mm (P <0.05). Significant improvements in PD, CAL, and BPD were noted in the test group when the crestal involvement exceeded 100 degrees. Correlation test between various clinical parameters indicated that greater changes in PD and CAL in the test group were observed when preoperative CAL was large (P<0.001), and greater changes in PD (P<0.05), CAL (P<0.01), and BPD (P<0.05) were noted when preoperative BPD was large. Correlation between crestal involvement and CAL change was noted only in the control group (P<0.01). High correlations were observed between PD changes and CAL changes and between CAL changes and BPD changes in both groups. CONCLUSIONS: Use of a bone substitute in a flap operation resulted in significantly greater improvements in CAL and BPD over flap operation alone and seemed to have positive effects in postoperative PD, CAL, and BPD in those cases with more severe preoperative CAL and BPD.

Adult↗
PubMed2001

Urinary calculi on computed radiography: comparison of observer performance with hard-copy versus soft-copy images on different viewer systems.

OBJECTIVE: The purpose of this study was to compare observer performance for detecting urinary calculi using abdominal computed radiography with hard-copy versus soft-copy images and with a high-resolution video monitor versus a liquid-crystal-display (LCD) monitor. MATERIALS AND METHODS: We compared observer performance for detecting urinary calculi using three sets of radiographs-hard-copy images, soft-copy images displayed on a LCD monitor (1280 x 1024 bits), and soft-copy images displayed on a high-resolution video monitor using receiver operating characteristic curve analysis with a continuous rating scale. Computed radiography was archived with a 2140 x 1760 pixel resolution and a 10-bit depth. The selected data set included 62 images: 27 images showing proven urinary calculi smaller than 6 mm and three in number, and 35 images containing no proven abnormalities. Eleven radiologists (three genitourinary radiologists and eight general radiologists) participated in the study. Interpretations of three sets of randomly distributed radiographs were performed individually in three separate sessions at 1-week intervals. RESULTS: No statistically significant differences were found in the area under the receiver operating characteristic curve for detecting urinary calculi or in the interpreting times between soft-copy and hard-copy images; the mean areas under the receiver operating characteristic curve of hard-copy images, soft-copy images displayed on an LCD monitor, and soft-copy images displayed on a high-resolution video monitor were 0.579, 0.610, and 0.732, respectively. However, soft-copy images showed relatively improved diagnostic accuracy among less experienced radiologists (p < 0.05). CONCLUSION: For detecting urinary calculi, soft-copy images offered a diagnostic accuracy similar to or slightly more accurate than that of hard-copy images obtained in a laser-printed film-based environment. The diagnostic performance with soft-copy images viewed on an LCD monitor was comparable to that of soft-copy images viewed on a high-resolution video monitor.

Data Display↗
PubMed2001

Clinical impacts of tumor cell contamination of hematopoietic stem cell products in metastatic breast cancer patients undergoing autologous peripheral blood stem cell transplantation: multicenter trial.

To determine whether the tumor cell contamination of peripheral blood stem cells influences clinical impacts on high-dose chemotherapy in patients with metastatic breast cancer, we analyzed carcinoembryonic antigen (CEA) mRNA in the apheresis products by nested RT-PCR (reverse transcriptase-polymerase chain reaction). A total of 38 metastatic breast cancer patients and ten normal healthy subjects as a negative control were included. Twenty out of 38 (51.3%) apheresis products from patients with metastatic breast cancer were positive for CEA mRNA. CEA mRNA was noted in 54.8% (17/31) of patients mobilized with chemotherapy plus G-CSF and 42.8% (3/7) of patients with G-CSF alone. There was no significant difference in age, estrogen receptor, menopausal status, mobilization method, disease free interval, or number of metastasis sites (1 vs > or = 2) between positive and negative groups. The presence of CEA mRNA in apheresis products did not influence the time to progression and overall survival in both groups. However, both the univariate and the multivariate analysis disclosed that the number of metastasis was associated with survival significantly. We suggest that the tumor cell contamination does not predict poor treatment outcome in patients with metastatic breast cancer.

Adult↗
PubMed2001

Is body mass index the prognostic factor in breast cancer?: a meta-analysis.

This study was performed to integrate the results of previous studies that investigated the relationship between body mass index (BMI) and prognosis in breast cancer. We reviewed the English literatures using the MEDLINE database from 1966 to 1999. The materials included 12 published articles with a total of 8,029 cases of breast cancer. The effect size was obtained from hazard ratio in each study. Homogeneity test was conducted before the integration of each effect size and the result demonstrated that the studies were heterogeneous. A random effect model was used to integrate the overall effect size. The integrated effect size was 1.56 (95% confidence interval, 1.22-2.00). In addition, publication bias should be accounted for because each published study was asymmetric in shape revealed by funnel plot. These results suggest that BMI have a prognostic significance in breast cancer. We believe that well-designed longitudinal studies, involving a large number of samples are required to resolve these issues.

Body Mass Index↗
PubMed2000

Regulation of Mst57Dc expression in male accessory glands of Drosophila melanogaster.

Mst57Dc has been isolated as a male accessory gland transcript of Drosophila melanogaster. Its product is a secretory protein, which is phosphorylated by protein kinase A. In the present study, the expression pattern of Mst57Dc was analyzed. It is preferentially expressed in but not restricted to the male accessory glands. Other than in the accessory glands, it is slightly expressed in other body parts, including the head and female body. In the accessory glands, a high level of expression was detected right after eclosion when the titer of juvenile hormone III (JHIII) reaches a peak. Its accumulation was increased by mating, which has been known to act via JH. In ap56f a JH-deficient mutant, the level of Mst57Dc transcripts was about 60% of the wild type. Moreover a JH-responsive element like palindromic sequence and several sequence motifs were found in the 5' and 3' flanking regions of Mst57Dc. Taken together, JH is proposed as a regulator of Mst57Dc gene expression.

Aging↗
PubMed2000

Detection of major putative periodontopathogens in Korean advanced adult periodontitis patients using a nucleic acid-based approach.

BACKGROUND: Although extensive microbial analyses have been performed from subgingival plaque samples of periodontitis patients, systematic analysis of subgingival microbiota has not been carried out in a Korean population so far. The purpose of this study was to describe the prevalence of major putative periodontopathogens in Korean patients by culture-independent methods. METHODS: A total of 244 subgingival plaque samples (5 sites in each participant) were taken from 29 advanced adult periodontitis (AP) patients and 20 periodontally healthy subjects. AP samples were obtained from the 4 deepest periodontal pockets (> or =6 mm probing depth [PD]) and 1 healthy site (< or =3 mm PD) in each patient. Polymerase chain reaction (PCR) of 16S ribosomal DNA (rDNA) of subgingival plaque bacteria was performed with eubacterial primers. Aliquots of PCR products were then applied on nylon membranes and hybridized with specific oligonucleotide probes labeled with digoxigenin. RESULTS: All diseased sites harbored Fusobacterium sp., while Porphyromonas gingivalis, Treponema sp., and Bacteroides forsythus were detected in more than 96% of 116 diseased sites. Peptostreptococcus micros, Actinobacillus actinomycetemcomitans, and Prevotella intermedia were present in 82%, 74%, and 71% of diseased sites, respectively. In sites of periodontally healthy subjects, Fusobacterium sp. was present in the highest proportion (58%). Treponema sp., P. gingivalis, and B. forsythus were detected in 22%, 18%, and 18% of healthy sites, respectively. P. micros, P. intermedia, and A. actinomycetemcomitans were found in 8%, 2%, and 1% of healthy sites, respectively. The prevalence of the periodontopathogens, with the exceptions of Fusobacterium sp. and B. forsythus, was significantly higher in the healthy sites of periodontitis subjects than in the healthy sites of periodontally healthy subjects (P <0.05). CONCLUSIONS: Using highly sensitive methods relying on 16S ribosomal RNA-based oligonucleotide probes, we confirmed the strong association of 7 putative periodontopathogens with AP patients in a Korean population. With the exceptions of Fusobacterium sp. and B. forsythus, all the periodontopathogens were significantly more associated with the healthy sites of periodontitis subjects than in the healthy sites of periodontally healthy subjects.

Adult↗
PubMed2000

Radiologic findings of abdominal polyarteritis nodosa.

OBJECTIVE: The purpose of this study was to evaluate the radiographic and imaging findings of seven patients with polyarteritis nodosa involving the abdomen. CONCLUSION: Vasculitis should be considered when multiple abdominal organs have abnormal radiologic findings; however, angiography is necessary to specifically diagnose polyarteritis nodosa.

Abdomen↗
PubMed2000

CT of patients with right-sided colon cancer and distal ileal thickening.

OBJECTIVE: The purpose of this study was to analyze the incidence and primary causes of distal ileal wall thickening in 131 patients with right-sided colon cancer. SUBJECTS AND METHODS: During a 2-year period, 131 patients underwent surgical resection for right-sided colon cancer. Of these patients, we analyzed 13 who had distal ileal wall thickening on CT before surgery and also had the cause determined at pathology. CT findings were analyzed with regard to the morphologic features of colonic tumors, bowel wall involvement patterns of the distal ileum, and changes in the pericolic space. RESULTS: Distal ileal wall thickening occurred in 13 (10%) of the 131 patients who had right-sided colon cancer. Three patients had polypoid colon cancer, whereas the other 10 had infiltrative colon cancer. The mean thickness of the involved colonic segments was 1.6 cm (range, 1.0-2.2 cm) with a mean length of 5.2 cm (range, 2.5-10.0 cm). Pericolic infiltration was mild in six patients and moderate in four patients. The mean length and thickness of the affected ileal segments were 3.2 cm (range, 1.5-6.0 cm) and 1.1 cm (range, 0.7-2.0 cm), respectively. On histopathologic examination, neoplastic processes involved the distal ileum in nine (69%) of the 13 patients. This involvement was caused by either direct tumor invasion in seven patients or lymphatic spread in two. In four patients (31%), nonneoplastic processes with edema and congestion involved the distal ileum. CONCLUSION: The distal ileum may be abnormally thickened in about 10% of patients with right-sided colon cancer; this thickening results from tumor extension (69%) or a nontumorous process (31%).

Adult↗
PubMed2000

Chronological effects of atherogenic diets on the aorta, liver and spleen of rabbits.

To investigate the temporal progression of atherogenesis on the aorta and involvement of the monocyte-macrophage system in the liver and spleen, we fed 74 rabbits with high fat (14 or 7 gm%) and cholesterol (2 and 1%) diets for 4 to over 24 weeks. Using both light and electron microscopies, we found that the fibro-fatty areas on the luminal surface of aortas was spread over along the feeding time dependently. The fat deposits also in the liver and spleen worsened depending on the time of feeding the atherogenic diets. Not only monocyte-derived foam cells, but also parenchymatous cells in the liver and spleen involved become fat-laden cells. According to these results, we propose that there are three stages: 1) the primary seeding, 2) the intermediate maturing and 3) the advanced periods. These periods may play very important roles in designing the management and treatment of atherosclerotic patients.

Animals↗
PubMed2000

Stimulation of quiescent corneal endothelial cells by direct delivery of the SV40 large T-antigen protein.

PURPOSE: To determine whether the delivery of the SV40 large T-antigen is a feasible method for transiently inducing proliferation of corneal endothelial cells. METHODS: Liposome-mediated delivery of proteins into bovine corneal endothelial cells (BCEC) was utilized in this study. Initially, beta-galactosidase was used as a marker protein for cell delivery and cells were assayed colorimetrically for beta-galactosidase activity. Subsequently, SV40 large T-antigen protein was introduced into BCEC and positive cells were identified by immunohistochemistry 24 hours after liposome-protein treatment. Quiescent BCECs were double-labeled using BrdU as a measure of de novo DNA synthesis and the SV40 large T-antigen was detected by standard immunohistochemical methods. RESULTS: Beta-galactosidase or SV40 large T antigen were introduced into BCECs using liposome transfer methods. The transfer efficiency of beta-galactosidase was > 30% of the cells. SV40 large T antigen was successfully introduced and was localized to the nuclei of BCECs. The treatment of quiescent BCECs with large T antigen caused an increase in BrdU incorporation. Co-labeling confirmed that only cells containing SV40 large T antigen were positive for de novo DNA synthesis. CONCLUSIONS: This study demonstrates that proteins can be inserted directly into corneal endothelial cells. In the case of the SV40 large T-antigen, the protein localized to the nucleus and maintained its bioactivity by inducing DNA synthesis. This finding suggests that liposome-mediated delivery of transforming proteins could be a method to transiently induce corneal endothelial cell proliferation.

Animals↗
PubMed2000

Biological deodorization of hydrogen sulfide using porous lava as a carrier of Thiobacillus thiooxidans.

Biological deodorization of hydrogen sulfide (H2S) was studied using porous lava as a carrier of Thiobacillus thiooxidans in a laboratory-scale biofilter. Three different samples of porous lava, A, B, and C, which were obtained from Cheju Island in Korea, were used. The water-holding capacities of samples A, B and C were 0.38, 0.25, and 0.47 g-H2O/g-lava, respectively. The pHs and densities of the lava samples ranged from 8.25-9.24 and 920-1190 kg/m3, respectively. The buffering capacities, expressed as the amount of sulfate added to lower the pH to 4, were 60 g-SO4(2-)/kg-lava for sample A, 50 g-SO4(2-)/kg-lava for B, and 90 g-SO4(2-)/kg-lava for C. To investigate the removal characteristics of H2S by the lava biofilters, T. thiooxidans was immobilized on the lava samples. Biofilters A and C showed a removal capacity of 428 g-S.m(-3).h(-1) when H2S was supplied with 428 g-S.m(-3).h(-1) of inlet load at a space velocity (SV) of 300 h(-1). At the same inlet load and SV, the removal capacity of biofilter B was 396 g-S.m(-3).h(-1). The H2S critical loads of biofilters A, B and C at a SV of 400 h(-1) were 396, 157 and 342 g-S.m(-3).h(-1), respectively. It is suggested that natural, porous lava is a promising candidate as a carrier of microorganisms in biofiltration.

Journal Article↗
PubMed1999

Synergistic effect of optic and peripheral nerve grafts on sprouting of axon-like processes of axotomized retinal ganglion cells in adult hamsters.

We investigated the sprouting response of retinal ganglion cells (RGCs) following the transplantation of peripheral nerve (PN) and/or optic nerve (ON) into the vitreous of the eye and the intraorbital transection of the optic nerve in hamsters. Our previous results showed that an intravitreal PN graft could induce sprouting of axon-like processes in axotomized RGCS [3] (Cho, E.Y. and So, K.F., Characterization of the sprouting response of axon-like processes from retinal ganglion cells after axotomy in adult hamsters: a model using intravitreal implantation of a peripheral nerve, J. Neurocytol., 21 (1992) 589-603). In this model, we have examined the effect of intravitreal ON graft on the sprouting of RGCs both following a co-transplantation of PN and ON into the vitreous and transplantation of ON alone. The present results show that sprouting is increased by more than two-fold in retinas having PN and ON grafts than a PN graft alone. However, the ON graft by itself rarely induced sprouting in RGCs. These results suggest that the ON graft enhance the number of RGCs to sprout axon-like processes in the presence of PN graft by exerting a synergistic rather than an additive effect, since ON graft alone did not induce sprouting. In addition, no diffusible inhibitory effect of ON graft on PN induced sprouting was observed.

Age Factors↗
PubMed1999

Ciliary neurotrophic factor promotes the regrowth capacity but not the survival of intraorbitally axotomized retinal ganglion cells in adult hamsters.

Ciliary neurotrophic factor has recently been shown to promote the axonal regrowth of retinal ganglion cells into a peripheral nerve graft following an intracranial transection of the optic nerve (approximately 7 mm from the optic disc). It is unclear whether the enhancement of axonal regrowth by ciliary neurotrophic factor application correlates with the enhancement of survival of retinal ganglion cells and/or the up-regulation of expression of growth-associated protein-43 messenger RNA in retinas. The present study evaluated the regenerative capacity of retinal ganglion cells following intraorbital transection of the optic nerve (approximately 1.5 mm from the optic disc) and the attachment of a peripheral nerve to the ocular stump of the optic nerve. In addition, we have determined the survival of retinal ganglion cells and the expression of growth-associated protein-43 messenger RNA in ciliary neurotrophic factor-treated retinas following optic nerve transection. The results showed that in the ciliary neurotrophic factor-treated retinas, the number of retinal ganglion cells which had regrown axons into a peripheral nerve is about four times more than the control. In the axotomized retinas, ciliary neurotrophic factor initiated sprouting of axon-like processes at 14 and 28 days post-axotomy and up-regulated the expression level of growth-associated protein-43 messenger RNA at 7, 14 and 28 days post-axotomy. However, ciliary neurotrophic factor did not prevent the death of axotomized retinal ganglion cells. We suggest that one possible mechanism for the axonal regeneration of axotomized retinal ganglion cells by ciliary neurotrophic factor could be mediated by the up-regulation of growth-associated protein-43 gene expression and not by increasing the pool of surviving retinal ganglion cells after axotomy.

Animals↗
PubMed1999

A 45-kDa cAMP-dependent phosphoprotein which is related to the product of Mst57Dc in Drosophila melanogaster.

In Drosophila, the catalytic subunit of cAMP-dependent protein kinase (PKA) is preferentially expressed in the brain and the male reproductive organs. Although the cAMP response element binding protein (CREB) is a major target of PKA in the brain, the target of PKA in the male reproductive organs has been unknown. In the present study, three cAMP-dependent phosphoproteins (referred to as pp45, pp20, and pp10) were detected in the lumen fluid of male accessory glands. They were tissue-specific secretory proteins that accumulated only after eclosion, and were transferred to females during mating as other secretory proteins of the accessory glands. Among them, the 45-kDa phosphoprotein was partially purified and characterized. The purified protein was phosphorylated in vitro by the catalytic subunit of PKA. The partial amino acid sequence of this 45-kDa phosphoprotein was identical to the predicted amino acid sequence of the Mst57Dc cDNA, which is a male accessory gland transcript.

Amino Acid Sequence↗
PubMed1999

Microbial removal of Fe(III) impurities from clay using dissimilatory iron reducers.

Fe(III) impurities, which detract refractoriness and whiteness from porcelain and pottery, could be biologically removed from low-quality clay by indigenous dissimilatory Fe(III)-reducing microorganisms. Insoluble Fe(III) in clay particles was leached out as soluble Fe(II), and the Fe(III) reduction reaction was coupled to the oxidation of sugars such as glucose, maltose and sucrose. A maximum removal of 44-45% was obtained when the relative amount of sugar was 5% (w/w; sugar/clay). By the microbial treatment, the whiteness of the clay was increased from 63.20 to 79.64, whereas the redness was clearly decreased from 13.47 to 3.55.

Journal Article↗
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

Periodontal repair in dogs: effect of rhBMP-2 concentration on regeneration of alveolar bone and periodontal attachment.

The objective of this study was to evaluate the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) concentration on regeneration of alveolar bone and cementum, and on associated root resorption and ankylosis. Contralateral, critical size, supra-alveolar, periodontal defects were surgically produced and immediately implanted with rhBMP-2 in an absorbable collagen sponge (ACS) carrier in 8, young adult, male, beagle dogs. 6 animals received rhBMP-2/ACS (rhBMP-2 at 0.05, 0.10, or 0.20 mg/mL; total construct volume/defect approximately 4.0 mL) in contralateral defects following an incomplete block design. 2 animals received rhBMP-2/ACS (rhBMP-2 at 0 and 0.10 mg/mL) in contralateral defects (controls). The animals were euthanised at 8 weeks post-surgery and block sections of the defects were collected for histologic and histometric analysis. Supra-alveolar periodontal defects receiving rhBMP-2 at 0.05, 0.10, or 0.20 mg/ml exhibited extensive alveolar regeneration comprising 86%, 96%, and 88% of the defect height, respectively. Cementum regeneration encompassed 8%, 6%, and 8% of the defect height, respectively. Root resorption was observed for all rhBMP-2 concentrations. Ankylosis was observed in almost all teeth receiving rhBMP-2. Control defects without rhBMP-2 exhibited limited, if any, evidence of alveolar bone and cementum regeneration, root resorption, or ankylosis. Within the selected rhBMP-2 concentration and observation interval, there appear to be no meaningful differences in regeneration of alveolar bone and cementum. There also appear to be no significant differences in the incidence and extent of root resorption and ankylosis, though there may be a positive correlation with rhBMP-2 concentration.

Absorbable Implants↗