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Biomedical subjects

B K Cho

Publications and source records attributed to B K Cho.

At least 19 recordsLinked to original sources
PubMed1995

Characterization of a single-chain antibody to the beta-chain of the T cell receptor.

In this report the VH and VL genes of the anti-T cell receptor (TCR) antibody KJ16, which recognizes the TCR V beta 8.1 and V beta 8.2 regions in mice, were cloned and expressed as a single-chain antibody (scFv) in Escherichia coli. A 29-kDa protein was obtained after renaturation from inclusion bodies. The KJ16 scFv had a relative affinity for the native TCR that was slightly higher than KJ16 Fab fragments. The scFv and Fab fragments of the KJ16 antibody, together with monovalent forms of two other anti-TCR antibodies, were evaluated as antagonists of the T cell-mediated recognition of a peptide-class I complex or of a superantigen, Staphylococcus enterotoxin B (SEB) bound to a class II product. Each of the anti-TCR antibodies was efficient at inhibiting the recognition of the SEB-class II complex. In contrast, only the clonotypic antibody, which binds to epitopes on both V beta and V alpha regions, inhibited the recognition of peptide-class I complex. We conclude that the TCR binding site for the SEB-class II ligand encompasses a larger surface area than the TCR binding site for the peptide-class I ligand.

Amino Acid Sequence↗
PubMed1995

Morphological study of surgically induced open neural tube defect in old (14 and 21 days) chick embryos.

As an experimental model for the research of open neural tube defect (NTD), the surgical model has several advantages over others, in spite of the fact that the pathogenetic mechanism is not compatible with the human intrauterine events. To make reproducible NTDs by surgery and to compare the surgically induced lesions with the human myeloschisis morphologically, we opened the neural tube for a length of 9-11 somites in Hamburger and Hamilton stage 16-19 chick embryos. Embryos which survived until the late in ovo life (total age 14 and 21 days) showed relatively reproducible open NTDs. Morphologically they are similar to human myeloschisis. This study suggests that the surgical model can be suitable for studies of open NTDs.

Age Factors↗
PubMed1995

Proximal migration and subcutaneous coiling of a peritoneal catheter: report of two cases.

The authors report two cases with a rare complication of ventriculoperitoneal shunt. The peritoneal catheters migrated upward to the scalp and to the clavicular area. In one case, the whole length of the peritoneal catheter was pulled out from the peritoneal cavity and was coiled subcutaneously. Both of the patients had the habit of head rotation and one of the patients had a history of subcutaneous fluid collection at the site of coiling. At surgery, whitish inflammatory granulation tissues were noted around the catheter in both cases, which might act as an anchoring point for the "windlass effect".

Child, Preschool↗
PubMed1995

Infarction of the territory supplied by the contralateral superior cerebellar artery in a case of descending transtentorial herniation.

Infarction of the territory supplied by the contralateral superior cerebellar artery in cases of descending transtentorial herniation has not been reported. The authors experienced a primitive neuroectodermal tumor in a patient whose consciousness deteriorated transiently due to descending transtentorial herniation. On the magnetic resonance imaging taken 8 days after the herniation, lesions thought to be infarction of territories supplied by the ipsilateral posterior cerebral artery and the contralateral superior cerebellar artery were noted. The possible mechanism of this peculiar pattern of infarction is discussed.

Arteries↗
PubMed1995

Systemic plasmacytosis: a case which improved with melphalan.

Plasmacytosis, a distinctive proliferative disorder of plasma cells, is characterized by peculiar multiple skin eruptions, lymphadenopathy and polyclonal hypergammaglobulinemia. To date there has been no report of such cases showing remarkable responses to therapeutic agents. We herein report a case of plasmacytosis which developed in a 52-year-old Korean man and showed remarkable improvement with melphalan.

Humans↗
PubMed1995

[Taxonomical approach to scabies mites of human and animals and their prevalence in Korea].

Three types, hitherto commonly known as varieties of Sarcoptes scabiei (Linnaeus, 1758) were collected from scabietic patients, pigs and dogs to confirm their taxonomic status. As a result, we consider that the mites of human and pig scabies are different subspecies [S. scabiei scabiei (Linnaeus, 1758) and S. scabiei suis Megnin, 1880, respectively], and that of dog scabies is a different species, S. canis Gerlach, 1857. Infestation rate of human scabies in Korea peaked in 1981-1982 and showed nearly 10% of prevalence rate among outpatients of the dermatology clinic, but decreased dramatically during the past ten years and now lowered below 1% since 1990. On the other hand, dog scabies seems to be increasing recently.

Adolescent↗
PubMed1995

Incidence and predictors of postextubation laryngeal edema in pediatric patients with congenital heart disease.

Laryngeal edema developed in 10.1% of studied patients with congenital heart disease after cardiac surgery. The 181 patients were divided into two groups; those with laryngeal edema (group 1) and those without laryngeal edema (group 2). The mean ages in group 1 and 2 were 10 and 22.9 months. Group 1 patients were younger on average than those of group 2 (p < 0.05). The differences in the cardiopulmonary bypass time and anesthesia time between the two groups were not statistically significant. The duration of intubations and ventilatory support before and after the onset of laryngeal edema and the period of the ICU stay were longer in group 1 than in group 2 (P < 0.05). A predictor of postextubation laryngeal edema was not found in our patients from above mentioned parameters. We conclude that the higher incidence of laryngeal edema may be due to young age (most were under 1 year of age), and duration of intubation and ventilatory support.

Adolescent↗
PubMed1995

Use of a 64 channel computerized cardiac mapping system in arrhythmia surgery.

A multipoint and computerized intraoperative mapping system has been known to be of value in improving the results of surgery for cardiac arrhythmia. It shows great potential as a new tool in the surgical intervention of the more common and lethal types of supraventricular tachyarrhythmias such as atrial flutter and atrial fibrillation. In addition, it also enhances the ability of the investigators to map and ablate the sometimes fleeting automatic atrial tachycardia. The authors developed a 64 channel computerized cardiac mapping system using a microcomputer (Macintosh IIx) and this has been used for basic research in cardiac electrophysiology as well as in arrhythmia surgery. In this system, bipolar electrograms are obtained from 64 different cardiac sites simultaneously at a sampling rate of 1 Ksample/sec and with a continuous and total data storage of up to 30 seconds. When the reference electrode is selected, delay time from the reference point is displayed on a two dimensional diagram of the heart. This system was used in one patient who underwent a surgical ablation of a ventricular tachycardia in whom we observed a ventricular activation sequence involving a variety of rhythms over several minutes. The system design permits easy expansion to a simultaneous sampling from 256 sites. This 64-channel mapping appeared to have the potential to be of great help in our understanding of cardiac arrhythmia as well as in its diagnosis and surgical treatment.

Arrhythmias, Cardiac↗
PubMed1994

Milia en plaque.

Explore the source record for details and available documents.

Adolescent↗
PubMed1994

Tick bites in Korea.

BACKGROUND: Tick bites are dermatoses not commonly encountered in Korea. Recognizing their clinical signs as well as their histopathologic findings is important in making a diagnosis of tick-related dermatoses. The incidence and causative species are different depending on the geographic areas. The histopathologic findings of tick bites are known to be a variable depending on the species of ticks involved and the duration of their bloodsucking. METHODS: Five ticks were collected from five patients and three of them were identified as Ixodes (I.) nipponensis. RESULTS: Histopathologic findings of panniculitis were prominent in four of five cases; septal panniculitis in two cases, and lobular panniculitis in the other cases. CONCLUSIONS: Ixodes nipponensis was the most common causative species of ticks responsible for tick bites in Korea, and tick bite panniculitis must be considered in the differential diagnosis of panniculitis which is mainly composed of neutrophils.

Aged↗
PubMed1994

Treatment outcome and prognostic factors of medulloblastoma.

Medulloblastoma, once a tumor with a dismal prognosis, is one of the most common primary brain tumors of childhood. As the methods of treatment have been continuously refined, the outcome has improved remarkably during the last few decades. The outcome of 78 medulloblastoma patients, which were managed from 1972 to 1992 at the Department of Neurosurgery of Seoul National University Hospital, were analyzed to calculate the 3-year and 5-year survival rates (3yS and 5yS). Of those, 52 cases which were treated after July 1982 were studied 1) to calculate the 3yS and 5yS, 2) to figure out the prognostic factors of survival, and 3) to investigate the role of adjuvant chemotherapy ('8-drugs-in-a-day' protocol: CCNU, cisplatin, vincristine, hydroxyurea, procarbazine, cytosine arabinoside, methylprednisolone and cyclophosphamide). The 3yS and 5yS of the 78 patients were 57.4% and 47.3%, respectively. Of the 52 patients treated after July 1982, the 3yS and 5yS were 67.8% and 64.1%, respectively. The latest recurrence was at 56 months after surgery. All the recurrences were within the risk period of Collins' rule. Of the prognostic factors studied by univariate analysis (age, sex, Chang's classification T- and M-stages, extent of surgical removal, and chemotherapy), Chang's classification M-stage and sex were the statistically significant factors (p = 0.028 and 0.024 respectively). On multivariate analysis, only the M-stage was statistically significant (p = 0.004). Adjuvant chemotherapy had different influences in different patient groups. Only in the 'poor risk' group, did adjuvant chemotherapy have a strong tendency to better outcome (p = 0.069). Further data collection and analysis will lead to better treatment modalities and better outcome for this most common primary malignant brain tumor in childhood.

Adolescent↗
PubMed1994

Diastematomyelia--clinical manifestation and treatment outcome.

Diastematomyelia is a rare congenital anomaly characterized by a division of the spinal cord or the filum terminale into two parts. In Korea, only one case has been reported. The authors have operated on 5 cases of diastematomyelia with septum since July, 1978. The ages ranged from 1 to 44 years (median; 11 years). There were 2 boys, 2 girls and an adult man. The disease manifested by cutaneous abnormalities and neurological or orthopedic deficits. Pain was a chief complaint in the adult patient. The symptoms had progressed in 3 cases. The diagnosis was made correctly by CT myelography or MRI in 4 cases. The median septum was located at the lumbar area in 4 cases and at the lumbosacral region in 1 case. Associated abnormalities included low lying conus (5 cases), lipoma (2 cases), thickened filum terminale (1 case), hemilipomyelomeningocele (1 case) and syrinx (1 case). The median septum was removed. The dural sleeve adjoining the septum was resected and the dural sac was reconstructed. The role of MRI in the diagnosis and planning of surgery and the high frequency of associated low lying conus were emphasized. Though the surgical treatment relieved pain, it did not reverse the neurological deficits or orthopedic deformities significantly, which suggests the beneficial effects of early surgical intervention in the cases with progressive symptoms.

Adolescent↗
PubMed1994

In vitro pressure drop comparison between two mechanical valve prostheses.

An hemodynamic evaluation of two mechanical heart valves is presented. A tilting disc valve and a bileaflet valve were incorporated in a mock circulatory system which consists of a closed flow loop with a pneumatically driven flexible diaphragm to simulate the physiologic pulsatile flow. Comparisons between the valves were made on the aortic pressure, ventricular pressure, as well as mean pressure gradient at a systolic duration of 45% and a heart rate of 90 beats per minute. The results showed that the tilting disc valve has higher ventricular pressure and mean pressure gradient than that of the bileaflet valve. This indicates that the tilting disc valve has higher transvalvular flow resistance and energy loss than that of the bileaflet valve. From this study it is demonstrated that the mock circulatory system can be a very useful device to evaluate the prosthetic heart valves in vitro.

Heart Valve Prosthesis↗
PubMed1994

In vitro sound spectral analysis of prosthetic heart valves by mock circulatory system.

A comparative study was made of the sounds produced by normal prosthetic valves (St. Jude Medical, Bjork-Shiley, polymer) with those produced by the same valves but having simulated thrombosis at the stent, hinge, or strut. Comparisons of the closing sound were made for the power frequency spectra associated with individual valves. We used periodogram approach to obtain the spectral characteristics of the valve prostheses. The closing sound of the abnormal mechanical valves displayed lower apparent peak frequency. But the abnormal polymer valve produced higher apparent peak frequency. The results showed that frequency spectra gave information pertinent to the simulated malfunction. Sound spectral analysis is believed to be a simple and a good diagnostic tool for detection of prosthetic valve malfunction. Also it seemed to be superior to other methods such as phonocardiography and echocardiography.

Fourier Analysis↗
PubMed1994

Mechanism of decrease in heart rate by peripheral dopaminergic D2-receptors.

We performed this study in order to verify the heart rate decrease caused by the D2-receptor on cardiac sympathetic nerve endings and its relation to the concentration of norepinephrine in synaptic clefts. Sprague-Dawley rats were pithed and the heart rate was increased either by electrical stimulation of the cardiac accelerator nerve or by intravenous infusion of norepinephrine, tyramine, or isoproterenol. Increased heart rate by electrical stimulation of cardiac accelerator nerve was dose-dependently lowered by lisuride and its effect was blocked by pretreatment with sulpiride but not with yohimbine and SCH 23390. Also, the heart rate was decreased in a dose-dependent manner by clonidine and this effect was blocked by pretreatment with yohimbine, but not with sulpiride. For increased heart rate by infusion of norepinephrine, tyramine, or isoproterenol, the heart rate lowering effect of lisuride was more marked in the norepinephrine-and tyramine-infusion groups, in which the intrasynaptic concentration of norepinephrine was elevated, compared to the isoproterenol-infusion group, in which intrasynaptic concentration of norepinephrine was not elevated. In conclusion, there is a D2-receptor on the cardiac sympathetic nerve endings which decreases the heart rate and is different from the presynaptic alpha 2-receptor. Also, the heart rate lowering effect via stimulation of the D2-receptor by lisuride was more marked with increased concentration of norepinephrine in the synaptic cleft.

Animals↗
PubMed1993

Intracranial mesenchymal chondrosarcoma: a case report and literature review.

Intracranial mesenchymal chondrosarcoma is a rare entity. The case of a 13-year-old girl with mesenchymal chondrosarcoma which seemed to arise from the dura mater is presented here together with a review of the literature. In the present case, the tumor involved the superior sagittal sinus. It recurred 21 months after gross total removal of the mass and coagulation of the involved wall of the superior sagittal sinus. Reoperation was performed followed by radiation therapy.

Adolescent↗
PubMed1993

Spinal cord ganglioglioma in childhood.

Two childhood cases of spinal cord ganglioglioma are described. Both cases showed a remarkable similarity in presentation, radiologically and morphologically. The first case was a 6 1/2-year-old boy who had ganglioglioma involving the entire length of the spinal cord. He has been suffering from a long span of scoliosis and gait disturbance since he was 1 year. The tumor contained multiple syrinx. The second case was a 3-year-old girl with ganglioglioma involving a large portion of the spinal cord from lower medulla to T3. This case also contained syringobulbia and syringomyelia in the multiple levels. She suffered from progressive motor weakness of all extremities. Owing to a good demarcation from normal spinal cord, the tumors could easily be removed by the microsurgical dissection through second stage operation in both cases. Histopathologically and ultrastructurally, the tumors were benign gangliogliomas. The symptoms improved a lot after surgery. Based on our two cases and literature review we confirmed that the spinal cord gangliogliomas are slowly growing tumors occurring in childhood or young adulthood. They often involve usually extensive level or entire length of the spinal cord and may be accompanied by scoliosis and gait disturbance when the tumor presents since infancy or early childhood as in our cases. They also often exhibit a cystic change of the tumor associated with large or small syringomyelia. Nearly total removal is possible due to a good demarcation from the normal spinal cord. Therefore, early diagnosis and surgical management are fundamental for the avoidance of unnecessary delay of surgery and a good result.

Child↗