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Biomedical subjects

S C Cho

Publications and source records attributed to S C Cho.

At least 19 recordsLinked to original sources
PubMed2005

Bilateral isolated phrenic neuropathy causing painless bilateral diaphragmatic paralysis.

The authors report four patients with a syndrome of painless bilateral isolated phrenic neuropathy. Electrophysiologic testing demonstrated active denervation restricted to the diaphragm. Long-term recovery was poor. The authors conclude that bilateral isolated phrenic neuropathy is a cause of painless diaphragmatic paralysis distinguishable from immune brachial plexus neuropathy and other neuromuscular disorders with similar clinical presentation.

Adult↗
PubMed2005

Psychiatric morbidity of second and third grade primary school children in Korea.

This study was undertaken to identify psychiatric morbidity among Korean second and third elementary school children using an objective diagnostic interview tool. Data from 5,118 (2,723 boys, 2,395 girls; mean age = 8.41 years (SD = 0.66)) second and third grade schoolchildren were drawn from 28 elementary schools. After initial screening assessments using the 28-item Child Problem-Behavior Screening Test for parents, 672 primary caregivers were subjected to secondary screening using the Korean version of the CBCL. Two hundred and seventy-one high-risk children selected according to the K-CBCL results, 138 (50.9%) children and their primary caregivers were interviewed using the Korean version of K-SADS-PL for objective DSM-IV psychiatric diagnoses. Sixty-four (46.4%) of the hundred and thirty eight children were determined to have at least one psychiatric disorder. More boys were diagnosed as psychiatric patients than girls (46 males, 18 females; OR = 2.21). The most frequently diagnosed disorder was ADHD (46/64; 71.9%), followed by tic disorder, anxiety disorders, mental retardation, oppositional defiant disorder, and separation anxiety disorder. Two or more comorbid psychiatric disorders were found in 22 (34.4%) of the 64 patients. The computed crude percentage of psychiatric patients in this study was 4.12%, which is similar to previously published data.

Child↗
PubMed2004

A case of 49,XXXXX in which the extra X chromosomes were maternal in origin.

This report describes an 11 month old female baby with features of pentasomy X. A molecular and cytogenetic evaluation revealed that her karyotype was 49,XXXXX and her extra X chromosomes were of maternal origin. She has muscular hypotonia, mental retardation, a cleft palate, mild hydrocephalus as a result of dilatation of both lateral ventricles, hyperextensible elbow joints, proximal radioulnar synostosis, clinodactyly of the fifth finger, valgus of the feet, and small hands and feet. In addition, she has a persistent pupillary membrane and congenital chorioretinal atrophy. The pathogenesis of pentasomy X is not clear at present, but it is thought to be caused by successive maternal non-dysjunctions.

Abnormalities, Multiple↗
PubMed2001

Methylphenidate increased regional cerebral blood flow in subjects with attention deficit/hyperactivity disorder.

The regional cerebral blood flow (rCBF) responses to methylphenidate (MPH) treatment were examined in children with attention deficit/hyperactivity disorder (ADHD). Thirty-two male children, diagnosed with ADHD by the DSM-IV diagnostic criteria, other behavioral assessment scales and neuropsychological battery, were studied using 99mTc-HMPAO-single photon emission computed tomography (SPECT). Subjects were studied before and after MPH treatment. First, using an image subtraction method, we obtained a NDR parametric image of each patient and found increased cerebral blood flow in the frontal lobes, caudate nuclei and thalamic areas after treatment. When the changes in SPECT and clinical response were compared, the matching rate, sensitivity and specificity between them were found to be 77.1, 80.0 and 79.2%, respectively. Second, three transaxial brain slices delineating anatomically defined regions of interest (ROI) at 20, 40, and 60mm above the orbitomeatal line (OML) were used, with the average number of counts for each region of interest normalized to the area of the cerebellar maximal uptake. The left and right prefrontal areas, and caudate and thalamic areas showed significant increases in rCBF after MPH treatment. These findings suggested MPH could affect the function of the fronto-striato-thalamic circuit, which is known as the pathophysiologic site of ADHD and could be used to correct the underlying brain dysfunction of ADHD.

Adolescent↗
PubMed2001

A prospective 2-year clinical evaluation of overdentures attached to nonsplinted implants utilizing ERA attachments.

Edentulism is a major oral healthcare issue for an ever-increasing older population in the United States. Most previous studies examined the success of overdentures supported by splinted implants utilizing clip bars and other types of attachments. This longitudinal study of 10 consecutive patients involves mandibular overdentures supported by nonsplinted implants with ERA attachments. Two-year results indicate that nonsplinted implants can be successfully used with ERA attachments to support overdentures. Each patient reported increased satisfaction with comfort, chewing, retention, and phonetics with the implant-assisted ERA-retained overdenture.

Aged↗
PubMed2000

Chronic lung injury in preterm lambs: abnormalities of the pulmonary circulation and lung fluid balance.

Chronic lung disease of early infancy, or bronchopulmonary dysplasia, is a frequent complication of prolonged mechanical ventilation after premature birth. Pulmonary hypertension and edema are common features of this condition, which is often attributed to long-term, repetitive overinflation of incompletely developed lungs. The overall objective of this work was to examine the effects on the pulmonary circulation and lung fluid balance of different ventilation strategies using large versus small inflation volumes in an animal model of bronchopulmonary dysplasia. We studied 16 newborn lambs that were delivered prematurely (124+/-3 d gestation, term = 147 d) by cesarean section and mechanically ventilated for 3 to 4 wk. Ten lambs were ventilated at 20 breaths/min, yielding a tidal volume of 15+/-5 mL/kg, and six lambs were ventilated at 60 breaths/min, yielding a tidal volume of 6+/-2 mL/kg. All lambs received surfactant at birth and had subsequent surgery for closure of the ductus arteriosus and catheter placement to allow serial measurements of pulmonary vascular resistance and lung lymph flow. Chronic lung injury, documented by serial chest radiographs and postmortem pathologic examination, developed in all lambs irrespective of the pattern of assisted ventilation. Pulmonary vascular resistance, which normally decreases during the month after birth at term, did not change significantly from the first to the last week of study. Lung lymph flow, an index of net transvascular fluid filtration, increased with time in lambs that were ventilated at 20 breaths/min, but not in lambs ventilated at 60 breaths/min. Lymph protein concentration decreased with time, indicative of increased fluid filtration pressure, without evidence of a change in lung vascular protein permeability. Postmortem studies showed interstitial lung edema, increased pulmonary arteriolar smooth muscle and elastin, decreased numbers of small pulmonary arteries and veins, and decreased capillary surface density in distal lung of chronically ventilated lambs compared with control lambs that were killed either 1 d (same postconceptional age) or 3 wk (same postnatal age) after birth at term. Thus, chronic lung injury from prolonged mechanical ventilation after premature birth inhibits the normal postnatal decrease in pulmonary vascular resistance and leads to lung edema from increased fluid filtration pressure. These abnormalities of the pulmonary circulation may contribute to the abnormal respiratory gas exchange that often exists in infants with bronchopulmonary dysplasia.

Animals↗
PubMed2000

The effect of inter-implant distance on the height of inter-implant bone crest.

BACKGROUND: The biologic width around implants has been well documented in the literature. Once an implant is uncovered, vertical bone loss of 1.5 to 2 mm is evidenced apical to the newly established implant-abutment interface. The purpose of this study was to evaluate the lateral dimension of the bone loss at the implant-abutment interface and to determine if this lateral dimension has an effect on the height of the crest of bone between adjacent implants separated by different distances. METHODS: Radiographic measurements were taken in 36 patients who had 2 adjacent implants present. Lateral bone loss was measured from the crest of bone to the implant surface. In addition, the crestal bone loss was also measured from a line drawn between the tops of the adjacent implants. The data were divided into 2 groups, based on the inter-implant distance at the implant shoulder. RESULTS: The results demonstrated that the lateral bone loss was 1.34 mm from the mesial implant shoulder and 1.40 mm from the distal implant shoulder between the adjacent implants. In addition, the crestal bone loss for implants with a greater than 3 mm distance between them was 0.45 mm, while the implants that had a distance of 3 mm or less between them had a crestal bone loss of 1.04 mm. CONCLUSIONS: This study demonstrates that there is a lateral component to the bone loss around implants in addition to the more commonly discussed vertical component. The clinical significance of this phenomenon is that the increased crestal bone loss would result in an increase in the distance between the base of the contact point of the adjacent crowns and the crest of bone. This could determine whether the papilla was present or absent between 2 implants as has previously been reported between 2 teeth. Selective utilization of implants with a smaller diameter at the implant-abutment interface may be beneficial when multiple implants are to be placed in the esthetic zone so that a minimum of 3 mm of bone can be retained between them at the implant-abutment level.

Alveolar Bone Loss↗
PubMed2000

Histologic and clinical comparison of bilateral sinus floor elevations with and without barrier membrane placement in 12 patients: Part 3 of an ongoing prospective study.

In 1993 the Department of Implant Dentistry at New York University College of Dentistry began a long-term clinical, histologic, histomorphometric, and radiographic study of the sinus elevation procedure. One of the parameters under evaluation in this study is the effect of barrier membrane placement on the creation of vital bone in the grafted sinus cavity. This report presents a histologic and histomorphometric evaluation of healing with and without the placement of an expanded polytetrafluoroethylene (e-PTFE) barrier membrane over the lateral window at the time of sinus grafting. The data were collected from 12 patients who underwent bilateral sinus elevation surgery. In each of these 12 patients the same grafting material was used in both sinuses, making the presence or absence of an e-PTFE barrier membrane the only controlled variable. Under the conditions of this study, the results indicate that (1) placement of the barrier membrane tends to increase vital bone formation; (2) placement of a barrier membrane has a positive effect on implant survival; and (3) membrane placement should be considered for all sinus elevation procedures.

Bone Regeneration↗
PubMed1999

Chronic lung injury in preterm lambs. Disordered respiratory tract development.

The cause of chronic lung disease of early infancy, often called bronchopulmonary dysplasia (BPD), remains unclear, partly because large-animal models that reliably reproduce BPD have not been available. We developed a model of BPD in lambs that are delivered prematurely and ventilated for 3 to 4 wk after birth to determine whether the histopathology of chronic lung injury in premature lambs mimics that which occurs in preterm infants who die with BPD, and to compare two ventilation strategies to test the hypothesis that differences in tidal volume (VT) influence histopathologic outcome. The two ventilation strategies were slow, deep ventilation (20 breaths/min, 15 +/- 2 ml/kg body weight VT; n = 5) or rapid, shallow ventilation (60 breaths/min, 6 +/- 1 ml/kg body weight VT; n = 5). Lambs were delivered at 125 +/- 4 d gestation (term = 147 d), treated with surfactant, and mechanically ventilated with sufficient supplemental oxygen to maintain normal arterial oxygenation (60 to 90 mm Hg). Quantitative histologic analysis revealed lung structural abnormalities for both groups of experimental lambs compared with lungs of control term lambs that were < 1 d old (matched for developmental age; n = 5) or 3 to 4 wk old (matched for postnatal age; n = 5). Compared with control lambs, chronically ventilated preterm lambs had pulmonary histopathology characterized by nonuniform inflation patterns, impaired alveolar formation, abnormal abundance of elastin, increased muscularization of terminal bronchioles, and inflammation and edema. Slow, deep ventilation was associated with less atelectasis, less alveolar formation, and more elastin when compared with rapid, shallow ventilation. We conclude that prolonged mechanical ventilation of preterm lambs disrupts lung development and produces pulmonary histopathologic changes that are very similar to those that are seen in the lungs of preterm infants who die with BPD. This chronic lung disease is not prevented by surfactant replacement at birth, does not appear to require arterial hyperoxia, and is influenced by VT.

Animals↗
PubMed1999

Crown lengthening revisited.

Over the last 37 years, crown-lengthening procedures have been used predictably to restore teeth broken down from caries, trauma, and extensive wear. With crown lengthening, the dentogingival junction is "re-created" at a more apical level on the root to accommodate the junctional epithelium and the connective tissue attachment. Forced eruption can be used in addition, or as an alternative, to tooth lengthening. The authors discuss the indications for tooth lengthening, forced eruption, and orthodontic extrusion, as well as the treatment planning for these procedures.

Crown Lengthening↗
PubMed1998

Electroconvulsive shock does not induce c-fos and junB, but TIS1 and TIS8/zif-268, in neonatal rat hippocampus.

The induction in the animal brain of immediate early genes (IEGs) is known to be age-dependent, and it was suggested that, during neonatal period, signaling pathways for the induction of IEGs are immature. In this study, we investigated the induction of various IEGs in neonatal rat hippocampus after electroconvulsive shock (ECS). ECS did not induce c-fos and junB in the hippocampus of 7-day-old rat, but these genes were weakly induced at postnatal 14 days and to an adult level at postnatal 21 days; two other IEGs, TIS1 (NGFI-B, nur77) and TIS8 (zif-268, Egr-1, Krox-24, NGFI-A), were induced at postnatal 7 days, however. Our results suggested that during the neonatal period, signaling pathways for TIS1 and TIS8 induction in rat hippocampus after ECS are complete, while those for c-fos and junB are immature.

Animals↗
PubMed1998

Sinus floor elevation using anorganic bovine bone matrix (OsteoGraf/N) with and without autogenous bone: a clinical, histologic, radiographic, and histomorphometric analysis--Part 2 of an ongoing prospective study.

One of the goals of the sinus elevation procedure is the creation of vital bone to effect the osseointegration of dental implants placed in the posterior maxilla. With this goal in mind, in 1993 the Department of Implant Dentistry at New York University College of Dentistry began a long-term clinical, histologic, histomorphometric, and radiographic study of the sinus elevation procedure. The primary parameters included the effects of graft material selection, time allowed for graft maturation, and the effect of barrier membrane placement on the creation of vital bone in the sinus cavity. The effects of these and other parameters on implant survival rates were also to be evaluated. This paper reports the data collected on a subgroup of 113 sinus elevations that used anorganic bovine bone matrix (OsteoGraf/N) alone or in combination with autogenous bone and/or demineralized freeze-dried bone as a graft material. This is the second in a proposed series of papers that will result from this ongoing research project. The results of this study indicate that: OsteoGraf/N appears to be an effective graft material with a 98.2% implant survival rate to date: vital bone formation increased with time; vital bone formation increased moderately when demineralized freeze-dried bone allograft was added, and increased substantially when intraoral autogenous bone was added or when an expanded polytetrafluoroethylene membrane was used; and the increased height achieved by the procedure was stable over a 3-year period. Because of the high overall implant survival rate, it was not possible to determine the relationship between vital bone formation or membrane usage and implant survival.

Animals↗
PubMed1997

Role of neutrophils in lung vascular injury and edema after premature birth in lambs.

To investigate the role of neutrophils in the pathogenesis of respiratory distress after premature birth, we assessed the relationship between circulating neutrophil concentration and neutrophil accumulation in the lung, lung lymph and pleural liquid flow, and extravascular lung water in 10 chronically catheterized preterm lambs (127 +/- 1 days gestation) that were mechanically ventilated for 8 h after birth. Circulating neutrophil concentration transiently decreased within 2 h after birth and then returned to prenatal values by 6-8 h. The decrease in circulating neutrophil concentration was related directly to the accumulation of neutrophils in the air spaces, drainage of liquid and protein from the lung 6-8 h after delivery, and postmortem extravascular lung water. In additional studies, we intravenously administered mechlorethamine to 5 fetal lambs to reduce circulating neutrophils before delivery (neutrophil concentration before birth: 9 +/- 11 cells/microl). Compared with control lambs, neutrophil-depleted lambs had significantly less drainage of liquid (7.8 +/- 5.9 vs. 2.6 +/- 1.9 ml/h, respectively) and protein (116 +/- 74 vs. 42 +/- 27 mg/h, respectively) from the lung 6-8 h after birth and significantly less extravascular lung water at postmortem (6.5 +/- 0. 8 vs. 4.8 0.6 g/g dry lung, respectively). Thus neutrophils contribute to the pathogenesis of respiratory distress after premature birth by increasing lung vascular protein permeability and promoting lung edema.

Alkylating Agents↗
PubMed1997

Serum insulin-like growth factors (IGFs) and IGF binding protein (IGFBP)-3 in patients with gastric cancer: IGFBP-3 protease activity induced by surgery.

Recent findings have indicated that insulin-like growth factors (IGF-I and IGF-II) may play a role in neoplasia. Alteration of serum IGFs or IGF Binding Proteins (IGFBPs) have been reported in some tumors. In this study, we measured serum IGF-I, IGF-II and IGFBPs profile in gastric cancer by radioimmunoassay and Western ligand blots. The serum IGF-I level in gastric cancer was significantly lower than in control subjects (65.2 +/- 26.5 vs 148.4 +/- 55.2 ng/ml, p < 0.01) and was further decreased to 45.5 +/- 20.9 ng/ml after surgery. The serum IGF-II level was slightly higher than that in control subjects (826.3 +/- 360.2 vs 735.7 +/- 154.6 ng/ml) but it was significantly decreased after surgery (525.7 +/- 220.1 ng/ml, p < 0.05). The serum IGFBP-3 level was not significantly different from those in control subjects. However, we observed a decreased level of serum IGFBP-3 after surgery, and incubation of postoperative serum with control serum resulted in a significant reduction of IGFBP-3 level. The reduction of IGFBP-3 in postoperative serum was mainly due to surgery associated IGFBP-3 protease activity. This protease activity was totally inhibited by aprotinin, EDTA and PMSF but not by pepstatin and leupeptin. This inhibition pattern is consistant with cation dependent serine protease. We speculate that proteolysis of IGFBP-3 may contribute to increase the bioavailability of IGFs.

Adenosarcoma↗
PubMed1997

Cell and platelet adhesions on plasma glow discharge-treated poly(lactide-co-glycolide).

Surface treatment, such as plasma glow discharge treatment, onto poly(lactide-co-glycolide) (PLGA) has been investigated to improve the cell-, tissue- and blood-compatibility. Surface-treated samples were characterized by measurement with a contact angle goniometer and electron spectroscopy for chemical analysis (ESCA). The contact angles on the plasma-treated PLGA surfaces decreased with increasing plasma exposure time from 92 degrees to about 30 degrees, i.e., increased hydrophilicity. From the results of ESCA analysis of plasma-treated films, the incorporation of oxygen molecules into plasma onto the PLGA surface was observed. Cell adhesion and growth on plasma-treated PLGA surfaces were more active than on the control. Furthermore, the maximum adhesion and growth of cells in moderate hydrophilicity were investigated. Morphology of the adhered platelets on the plasma-treated PLGA surface showed less activity than on the control, and the number of adhered platelets on the plasma-exposed PLGA sample decreased with decreasing water contact angle. It seems that surface wettability of PLGA plays an important role in cell adhesion, spreading and growth, and platelet adhesion.

3T3 Cells↗