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Biomedical subjects

K S Cho

Publications and source records attributed to K S Cho.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1999

Anterior thalamoperforating artery aneurysm associated with internal carotid artery occlusion: case report.

OBJECTIVE AND IMPORTANCE: We describe a rare case of a ruptured distal anterior thalamoperforating artery aneurysm associated with right internal carotid artery occlusion. CLINICAL PRESENTATION: A 59-year-old woman experienced sudden occipital headache, vomiting, and subsequent coma as a result of massive intraventricular hemorrhage. An initial angiogram revealed only an occlusion of the right internal carotid artery just distal to the posterior communicating artery. Repeat angiography 1 month later, however, revealed a saccular aneurysm at a distal anterior thalamoperforating artery in addition to the occlusion of the internal carotid artery. INTERVENTION: We approached this aneurysm through the right temporal horn after opening the ambient cistern. The aneurysm, which was located in the brain parenchyma just medial to the temporal horn, was successfully resected. CONCLUSION: This rare aneurysm probably developed as a result of hemodynamic stress on the anterior thalamoperforating artery after occlusion of the internal carotid artery and/or secondary to chronic hypertension.

Aneurysm, Ruptured↗
PubMed1999

Ventricular pressure monitoring during bilateral decompression with dural expansion.

OBJECT: The management of massive brain swelling remains an unsolved problem in neurosurgery. Despite newly developed medical and pharmacological therapy, the rates of mortality and morbidity caused by massive brain swelling remain high. According to many recent reports, surgical decompression with dural expansion is superior to medical management in patients with massive brain swelling. To show the quantitative effect of decompressive surgery on intracranial pressure (ICP), the authors performed a ventricular puncture and measured the ventricular ICP continuously during decompressive surgery and the postoperative period. METHODS: Twenty patients with massive brain swelling who underwent bilateral decompressive craniectomy with dural expansion were included in this study. In all patients, ventricular puncture was performed at Kocher's point on the side opposite the massive brain swelling. The ventricular puncture tube was connected to the continuous monitor via a transducer device. The ventricular pressure was monitored continuously, during the bilateral decompressive procedures and postoperative period. The initial ventricular ICP was variable, ranging from 16 to 65.8 mm Hg. Immediately after the bilateral craniectomy, the mean ventricular ICP decreased to 50.2+/-16.6% of the initial ICP (range 5-51.5 mm Hg). Additional opening of the dura decreased the mean ICP by an additional 34.5% and reduced the ventricular pressure to 15.7+/-10.7% of the initial pressure (range 0-15 mm Hg). Ventricular pressure measured postoperatively in the neurosurgical intensive care unit was lowered to 15.1+/-16.5% of the initial ICP. The ventricular ICP trend in the first 24 hours after decompressive surgery was an important prognostic factor; if it was greater than 35 mm Hg, the mortality rate was 100%. CONCLUSIONS: Bilateral decompression with dural expansion is an effective therapeutic modality in the control of ICP. To obtain favorable clinical outcomes in patients with massive brain swelling, early decision making and proper patient selection are very important.

Adolescent↗
PubMed1999

Reactive oxygen species-induced apoptosis and necrosis in bovine corneal endothelial cells.

PURPOSE: The loss of corneal endothelial cells associated with aging and possibly other causes has been speculated to be related to exposure to reactive oxygen species (ROS). The current study was conducted to investigate, by use of photosensitizers, the underlying mechanisms involved in the death of bovine corneal endothelial cells (BCENs) caused by ROS. METHODS: BCEN cells in primary culture were treated with a photosensitizer (riboflavin or rose bengal) with light exposure. The patterns of cell damage and death were assessed using an acridine orange-ethidium bromide differential staining method, TdT-mediated dUTP nick-end labeling (TUNEL) assay, and transmission electron microscopy. The cytotoxicity was assayed by mitochondrial function using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) testing. Antioxidants, including catalase, L-histidine, salicylic acid, and superoxide dismutase, were used to determine the types of ROS involved. Activation of nuclear factor (NF)-kappaB was examined by fluorescent immunocytochemistry with anti-p65 antibody. RESULTS: Light-irradiated riboflavin or rose bengal resulted in a significant decrease in viability of BCEN cells. Chromosomal condensation and fragmentation were observed in apoptotic cells, and membrane lysis and damage of cell ultrastructures were observed in necrotic cells. Riboflavin induced apoptosis at 30 minutes and thereafter and induced necrosis after 2 hours. Rose bengal was shown to cause similar effects within half the time required for the effects of riboflavin. Catalase and salicylic acid were found to provide protection for BCENs from cytotoxic effects of riboflavin, and L-histidine was found to protect BCENs from cytotoxicity induced by rose bengal. Kinetic studies using immunocytochemistry showed that NF-kappaB was translocated into the nucleus within 15 minutes and 30 minutes after treatment with rose bengal and riboflavin, respectively. CONCLUSIONS: The cytotoxic effects of photo-irradiated riboflavin and rose bengal are shown to be mediated by two distinct but parallel pathways, one leading to apoptosis and the other to necrosis. Possible involvement of NF-kappaB in cell death is suggested. These findings provide potential leads for future investigation into the molecular mechanisms of loss of corneal endothelial cells related to aging, oxidative stress, and possibly other similar causes.

Acridine Orange↗
PubMed1998

OK-432 and 5-fluorouracil, doxorubicin, and mitomycin C (FAM-P) versus FAM chemotherapy in patients with curatively resected gastric carcinoma: a randomized Phase III trial.

BACKGROUND: The streptococcal agent OK-432 is used widely as a potent biologic response modifier. Accumulated evidence suggests that OK-432 exerts antineoplastic effects by a direct cytotoxic or inhibitory effect on tumor cells. The clinical efficacy of OK-432 has been reported for various tumors. In this randomized Phase III study, the authors compared 5-fluorouracil (5-FU), doxorubicin, mitomycin C, and the intradermal administration of OK-432 (FAM-P) with the standard FAM regimen in patients with gastric carcinoma who underwent curative resection. METHODS: From May 1988 until November 1991, a total of 99 patients were entered into this randomized trial. The patients were stratified according to the American Joint Committee on Cancer stage of disease (i.e., Stage IB, II, and III). Fifty patients were treated with the FAM regimen here and throughout text.: 5-FU, 750 mg intravenously (i.v.), on Days 1, 8, 29, and 36; doxorubicin, 30 mg/m2 i.v., on Days 1 and 29; and mitomycin C, 10 mg/m2 i.v., on Day 1. Forty-nine patients received the FAM-P regimen: 5-FU, 750 mg i.v., on Days 1, 8, 29, and 36; doxorubicin, 30 mg/m2 i.v., on Days 1 and 29; mitomycin C, 10 mg/m2 i.v., on Day 1; and OK-432 5.0 Klinishe Einheit (clinical unit) injected intradermally weekly. RESULTS: The survival difference was statistically significant between the patients receiving the FAM and FAM-P regimens (5-year survival of 52% vs. 62%; P = 0.04). A comparison between disease free survival in FAM and FAM-P patients showed a borderline advantage for the FAM-P group (P = 0.053). When Stage IB, Stage II, and Stage III patients were analyzed separately, the difference in survival between two regimens was significant in Stage III patients (P = 0.049) and the disease free survival was of borderline significance (P = 0.06), but not in patients with Stage IB and II disease. The significant toxicity of OK-432 was mild fever, which was controlled with acetaminophen. CONCLUSIONS: The results of this study show that OK-432 may be an active, well tolerated agent for the treatment of curatively resected gastric carcinoma. However, these findings should be confirmed by a multicenter randomized study with a large sample size.

Adenocarcinoma↗
PubMed1998

Alveolar bone formation at dental implant dehiscence defects following guided bone regeneration and xenogeneic freeze-dried demineralized bone matrix.

The present study evaluated rate and extent of alveolar bone formation in dental implant dehiscence defects following guided bone regeneration (GBR) and implantation of xenogeneic freeze-dried demineralized bone matrix (xDBM). A total of 16 titanium plasma-sprayed (TPS) and 16 hydroxyapatite-coated (HA) titanium cylinder implants were inserted in 4 mongrel dogs following extraction of the mandibular premolar teeth. Four implant sites per jaw quadrant (2 TPS and 2 HA implant sites) were prepared into extraction sockets in each dog. Buccal alveolar bone was removed to create 3 x 5 mm dehiscence defects. Two jaw quadrants in separate animals received GBR, GBR + xDBM, xDBM (control), or gingival flap surgery alone (GFS; control). Thus, four conditions were available for each implant type (TPS or HA): GBR, GBR + xDBM; xDBM and GFS. The animals received fluorescent bone labels to allow observations of rate and extent of bone formation. Animals were sacrificed at 12 weeks postsurgery and block sections were harvested for histologic analysis. There were no apparent histologic differences between TPS and HA implant defects. GBR and GBR + xDBM resulted in almost complete bone closure of the dental implant dehiscence defect. Rate of bone formation appeared higher following GBR alone. Extent of bone formation appeared somewhat greater following GBR + xDBM; however, delayed. xDBM alone did not adequately resolve the bony defect. In conclusion, GBR results in rapid, clinically relevant bone closure of dental implant dehiscence defects. Adjunctive implantation of xDBM does not appear to significantly improve the healing response in the model used.

Alveolar Process↗
PubMed1998

Periodontal repair in dogs: effect of allogenic freeze-dried demineralized bone matrix implants on alveolar bone and cementum regeneration.

The objective of this study was to evaluate alveolar bone and cementum regeneration following surgical placement of an allogenic, freeze-dried, demineralized bone matrix (DBM) cortical strip implant. Critical size, supraalveolar periodontal defects were surgically created around the second, third, and fourth mandibular premolar teeth in eight mongrel dogs. Contralateral jaw quadrants in six animals were randomly assigned to receive the DBM implant, or serve as surgical control. Two additional animals received bilateral DBM implants. Flaps were coronally advanced to submerge teeth and implants, and sutured. Three animals were exited from the study due to extensive early wound failure. Remaining animals were sacrificed at 8 weeks postsurgery. Histometric recordings included defect height, bone regeneration/DBM implant height, cementum regeneration height, root resorption, and ankylosis. Large areas of unresorbed DBM exhibiting fragmentation and empty osteocyte lacunae were observed adjacent to new bone formation, or bone formation was observed adjacent to or within the implant, often exhibiting ankylosis. Cementum regeneration appeared enhanced in shelter of the DBM implant. Histometric recordings (mean+/-SD) for DBM and control defects, respectively, were: defect height, 4.8+/-0.2 mm and 4.4+/-0.2 mm; bone regeneration/DBM implant height, 4.0+/-1.3 mm and 1.2+/-0.6 mm; cementum regeneration height, 1.4+/-0.4 mm and 0.7+/-0.2 mm; root resorption, 0.5+/-0.3 mm and 1.2+/-0.3 mm; and ankylosis, 0.5+/-0.2 mm and 0.1+/-0.1 mm without statistically significant differences between experimental conditions (N=3). Within the limitations of this study, the histologic observations suggest that surgical implantation of allogenic, freeze-dried DBM cortical strip implants may have a potential to support cementum regeneration, possibly by providing conditions for guided tissue regeneration, however, alveolar regeneration appears unpredictable.

Alveolar Bone Loss↗
PubMed1998

Periodontal repair in intrabony defects treated with a calcium sulfate implant and calcium sulfate barrier.

THIS RANDOMIZED, CONTROLLED, CLINICAL STUDY was designed to evaluate outcome following surgical implantation of an allogeneic, freeze-dried, demineralized bone matrix-calcium sulfate (DBM+CS) composite with a CS barrier in intrabony periodontal defects. Twenty-six patients contributing 26 deep intrabony defects completed the study. Thirteen patients received the DBM+CS implant. Thirteen patients received gingival flap surgery alone (GFS; control). Clinical outcome was assessed at 6 and 12 months postsurgery. At 12 months postsurgery, probing depth (PD) reduction (mean +/-SD) for the DBM+CS and GFS group was to 4.3+/-0.5 and 3.0+/-1.3 mm; clinical attachment gain was to 2.9+/-0.8 and 1.7+/-1.5 mm; and probing bone level gain was to 2.9+/-1.4 and 1.2+/-1.2 mm, respectively. There were no apparent differences between evaluations at 6 and 12 months postsurgery. Clinical improvements were significantly different from presurgery for both groups at both observation intervals (P < 0.01). There were no significant differences between groups in PD reduction and clinical attachment gain. Probing bone level gain was significantly greater in the DBM+CS group compared to controls (P < 0.05). In summary, surgical implantation of DBM+CS with a CS barrier resulted in reduced PD and improved attachment levels comparable to that achieved by gingival flap surgery alone. However, gain in probing bone levels in deep intrabony periodontal pockets assessed by clinical parameters was greater than that observed by gingival flap surgery alone. These changes were noted at both 6 and 12 months after surgery. This regenerative technique needs further biologic evaluation before being generally accepted.

Adult↗
PubMed1998

Effect of a calcium sulfate implant with calcium sulfate barrier on periodontal healing in 3-wall intrabony defects in dogs.

This controlled, split-mouth, preclinical study was designed to evaluate outcome following surgical implantation of an allogeneic, freeze-dried demineralized bone matrix-calcium sulfate (DBM+CS) composite with a CS barrier in 3-wall intrabony periodontal defects in 4 dogs. Control conditions included surgical implantation of DBM or CS and gingival flap surgery (GFS) alone. Three-wall intrabony defects (4x4x4 mm) were surgically created at the mesial and distal aspect of the maxillary and mandibular first and third premolars, respectively. Maxillary and mandibular defects each received 1 of the 4 experimental conditions. Experimental conditions were rotated between defect sites in subsequent animals. Block sections of the defects were collected at sacrifice 8 weeks postsurgery and processed for histometric analysis. Histometric defect height (means +/- SD) for the DBM+CS, DBM, CS, and GFS groups amounted to 4.2 +/- 0.5, 4.3 +/- 0.7, 4.0 +/- 0.2, and 4.1 +/- 0.2 mm, respectively. Connective tissue adhesion (connective tissue contact to the root without apparent cementum formation) amounted to 0.4 +/- 0.3, 0.4 +/- 0.3, 0.5 +/- 0.2, and 1.6 +/- 0.5 mm for the DBM+CS, DBM, CS, and GFS groups, respectively; the DBM+CS, DBM, and CS groups being significantly different from the GFS group (P < 0.05). Cementum regeneration amounted to 3.0 +/- 0.3, 3.1 +/- 0.4, 2.5 +/- 0.4, and 1.6 +/- 0.3 mm for the DBM+CS, DBM, CS, and GFS groups, respectively; the DBM+CS, DBM, and CS groups being significantly different from the GFS group (P < 0.05). Alveolar bone regeneration amounted to 2.7 +/- 0.4, 2.7 +/- 0.3, 1.8 +/- 0.5, and 0.7 +/- 0.1 mm for the DBM+CS, DBM, CS, and GFS groups, respectively; the DBM+CS, DBM, and CS groups being different from the GFS group (P < 0.05), and the DBM+CS and DBM groups being different from the CS group (P < 0.05). None of the DBM-containing implants provided evidence of bone metabolic activity. In summary, surgical implantation of DBM and CS, alone or in combination, may result in significantly improved regeneration of alveolar bone and cementum in this preclinical model. Observed regeneration is likely unrelated to a biologic activity inherent in DBM. Rather it appears that space-providing properties of the implants supported observed regeneration.

Alveolar Bone Loss↗
PubMed1998

A case of hemolytic uremic syndrome associated with Epstein-Barr virus infection.

The precise etiology of hemolytic uremic syndrome (HUS) is unknown. However, it has been associated with bacterial (Shigella, Salmonella, E. coli, S. pneumoniae), Bartonella, and viral (coxsackie, ECHO, influenza, varicella. Epstein-Barr) infections and with endotoxemia. Recently, we experienced a case of HUS in a 16-year-old boy who was in the acute phase of an Epstein-Barr virus (EBV) infection. He had typical manifestations of HUS and EBV infection. He also transiently presented disseminated intravascular coagulation. His renal dysfunction recovered by supportive care, including hemodialysis, plasmapheresis, antihypertensive medication and aspirin. We present this case with a review of the literature as the second report of HUS associated with EBV infection.

Adolescent↗
PubMed1997

Caffeine- and inositol 1,4,5-trisphosphate-induced 45Ca2+ releases in the microsomes of tracheal epithelial cells.

Major parts of microsomes prepared from the epithelial cells of porcine trachea were tight-sealed vesicles since they showed a saturation of 45Ca2+ uptake and spontaneous releases of stored 45Ca2+ by the treatments of Ca2+-ionophore and Ca2+ channel agonists. In the presence of caffeine (10 mM), the maximal release of microsomal 45Ca2+ was observed at the extramicrosomal Ca2+ concentrations between 0.1 approximately 1 microM and at below or above this range of Ca2+ concentration the releases were decreased, forming a bell-shaped curve. These results indicate that the microsomal 45Ca2+ releases were mediated by ryanodine receptor, a caffeine-sensitive Ca2+ channel. Caffeine (10 mM) released 30.2 +/- 5.9% of microsomal 45Ca2+ while inositol 1,4,5-trisphosphate (InsP3, 10 microM) released 18.4 +/- 3.0% of the stored 45Ca2+. Caffeine-induced and InsP3-induced 45Ca2+ releases were additive, implying that these two types of 45Ca2+ releases are from physically distinct microsomes. Procaine, an antagonist of ryanodine receptor, selectively blocked the effect of caffeine but not the effect of InsP3. The results suggest that the epithelial cells of porcine trachea have caffeine-sensitive Ca2+ store in addition to InsP3-sensitive one.

Animals↗
PubMed1997

Combined direct and indirect reconstructive vascular surgery on the fronto-parieto-occipital region in moyamoya disease.

Between January 1992 and December 1995, eight patients with Moyamoya disease, aged from 2 to 39 years, underwent encephalo-duro-arterio-myo-synangiosis (EDAMS) on the frontal region, superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis combined with encephalo-myo-synangiosis (EMS) on the parietal region and encephaloduro-arterio-synangiosis (EDAS) on the occipital region using the frontal and parietal branch of the STA and the occipital artery, respectively. The development of postoperative collateral formation was assessed by carotid angiography and the improvement of clinical symptoms was evaluated for over 1 year after the bypass surgery. Of the 13 sides which underwent EDAMS and STA-MCA anastomosis with EMS, 11 sides resulted in extensive revascularization on the frontoparietal region and two sides showed localized collaterals, whereas EDAS on the occipital region demonstrated extensive and localized revascularization in each four sides and no evidence of revascularization in two sides among ten sides which underwent the EDAS. The clinical improvement due to the combined reconstructive surgery was very excellent in the reduction of the incidence of transient ischemic attacks (TIA) and reversible ischemic neurologic deficits (RIND).

Adolescent↗
PubMed1997

Three-vessel view of the fetal upper mediastinum: an easy means of detecting abnormalities of the ventricular outflow tracts and great arteries during obstetric screening.

The three-vessel view is a transverse view of the fetal upper mediastinum is as simple to obtain as the four-chamber view. It demonstrates the main pulmonary artery, ascending aorta and superior vena cava in cross- or oblique sections. The purposes of this study were to describe the normal anatomy of the three-vessel view and to analyze what anatomical changes would occur in this view when there are lesions of the ventricular outflow tracts and/or great arteries. Sonograms of 29 fetuses with lesions involving the ventricular outflow tracts and/or great arteries were reviewed. Three-vessel views were evaluated in terms of vessel size, number, arrangement and alignment. Twenty-eight of 29 fetuses showed an abnormal three-vessel view that included abnormal vessel size (n = 12), abnormal alignment (n = 8), abnormal arrangement (n = 7) and abnormal vessel number (n = 3). The vessel size was abnormal in obstructive lesions of the right (n = 4) or the left (n = 8) side of the heart. An abnormal alignment was seen in tetralogy of Fallot (n = 6) and double-outlet right ventricle (n = 2) that showed anterior displacement of the aorta. An abnormal arrangement was seen in complete (n = 4) and corrected (n = 1) transposition, double-outlet right ventricle (n = 1) and pulmonary atresia with ventricular septal defect (n = 1). Only two vessels were seen in truncus arteriosus (n = 1). Four vessels were seen in persistent left superior vena cava (n = 2). A fetus with pulmonary atresia and intact ventricular septum showed a normal three-vessel view. In conclusion, most of the lesions involving the ventricular outflow tracts and/or great arteries showed an abnormal three-vessel view.

Aortic Valve Stenosis↗
PubMed1996

Induction of axon-like processes from axotomized retinal ganglion cells of adult hamsters after intravitreal injection of sciatic nerve exudate.

We have shown previously that intravitreous transplantation of a peripheral nerve (PN) graft stimulates a subpopulation of retinal ganglion cells (RGCs) to sprout axon-like processes. The present study examined whether the effect of PN graft was due to diffusible factors released from the graft. Injection of sciatic nerve exudate into vitreous of the eye induced the formation of axon-like processes. Significantly more RGCs with axon-like processes were stained after injection of exudate from the distal stump than the proximal stump of the transected sciatic nerve. Thus, our results showed that trophic factors released from the intravitreous PN can induce the formation of axon-like processes and that more trophic factors are secreted from the distal than the proximal stump of the transected sciatic nerve.

Animals↗