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Biomedical subjects

K Cho

Publications and source records attributed to K Cho.

At least 235 records · Page 13Linked to original sources
PubMed1992

Neovascularization effect with He-Ne laser in the rat trachea.

The tracheal tissue of a rat was heterotopically transplanted beneath the abdominal skin of a syngenetic rat, and the transplanted graft was irradiated with a He-Ne laser (2.41 J/cm2). Four or seven days following transplantation, Chinese ink staining was used to ascertain the number of newly generated vessels. Rats sacrificed on day 4 were divided into 3 groups, according to the number of laser irradiation treatments: A0, A2, and A4. Similarly, rats sacrificed on day 7 were divided into groups B0, B2, and B4. Among the A groups, vascular counts were 49.5 +/- 31.1 in group A0 (n = 6), 108.9 +/- 34.7 in group A2 (n = 7), and 90.9 +/- 24.6 in group A4 (n = 4). Neovascularization was significantly more pronounced in the irradiated groups that in the non-irradiated group. In the B groups, vascular counts were 148 +/- 58 in group B0 (n = 6), 146 +/- 56 in group B2 (n = 5), and 147 +/- 49 in group B4 (n = 5). There was no significant difference between the irradiated and non-irradiated B groups. Laser irradiation was determined to stimulate neovascularization, and the possibility of a clinical application for this procedure was suggested.

Animals↗
PubMed1992

Genetic analysis of the effects of Mtv-2 on the T cell repertoire in the WXG-2 mouse strain.

In this report, the T cell repertoire was studied in a natural genetic model system using a novel mouse strain (WXG-2) carrying a single pathogenic mouse mammary tumor virus (MMTV) provirus (Mtv-2) on an otherwise MMTV-free genetic background. The Mtv-2 provirus has complete biological activity, produces infectious milk-transmitted virus, and contributes to mammary carcinogenesis by an insertion mutation mechanism. In mice carrying the Mtv-2 provirus, T cells expressing V beta 14 were specifically deleted in mice with a functional MHC class II I-E gene but not in I-E- controls. The deletion of V beta 14+ T cells was more rapid in mice with the Mtv-2 provirus than in Mtv-2-free control mice infected with exogenous MMTV. In addition, the Mtv-2 deletion phenotype was age dependent. A slow depletion of V beta 14+ T cells was observed, and greater than 95% of the V beta 14+ T cells were eliminated by 6 months of age. These experiments indicate that (i) the Mtv-2 provirus encodes or regulates expression of a V beta 14-specific superantigen, (ii) interactions between Mtv-2 and other MMTV proviruses are not necessary for the V beta 14 deletion phenotype, (iii) the presence of a retroviral superantigen in all cells is not sufficient for T cell depletion during neonatal development in the thymus, and (iv) the Mtv-2 provirus and its associated exogenous provirus have the same V beta specificity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Surfactant replacement therapy in premature babies with respiratory distress syndrome: factors affecting the response to surfactant and comparison of outcome from 1982-86 and 1987-91.

The impact of surfactant therapy on chronic lung disease remains uncertain. During the past decade (1982-91), over 300 babies with respiratory distress syndrome (RDS) weighing 501-2,500 g at birth were consecutively treated with surfactant-TA at our neonatal intensive care unit. Data on 95 RDS babies treated in the first 5 year period (Period 1, 1982-86) were compared with those on 158 RDS babies treated in the second 5 year period (Period 2, 1987-91). Overall respiratory improvement was better in Period 2 than in Period 1. In Period 2, surfactant therapy converted 98% of the babies with moderate/severe RDS to those with 'near normal' lung by 72 hr post-treatment. In Period 2, 95% of the surfactant-treated babies weighing 501-1,750 g at birth survived, 97% of which required no supplemental oxygen at 40 weeks corrected gestational age. Increased survival rate in the surfactant-treated babies during the past decade has not been followed by a parallel increase in chronic lung disease. The severity of the initial pulmonary disease per se was not the significant risk factor for chronic lung disease. Several other variables affecting the response to surfactant therapy and outcome have been identified by stepwise logistic regression analysis and include factors related to perinatal events such as birth asphyxia and infection, and other complications of prematurity.

Chronic Disease↗
PubMed1992

Progression of colorectal cancer is associated with multiple tumor suppressor gene defects but inhibition of tumorigenicity is accomplished by correction of any single defect via chromosome transfer.

Carcinogenesis is a multistage process that has been characterized both by the activation of cellular oncogenes and by the loss of function of tumor suppressor genes. Colorectal cancer has been associated with the activation of ras oncogenes and with the deletion of multiple chromosomal regions including chromosomes 5q, 17p, and 18q. Such chromosome loss is often suggestive of the deletion or loss of function of tumor suppressor genes. The candidate tumor suppressor genes from these regions are, respectively, MCC and/or APC, p53, and DCC. In order to further our understanding of the molecular and genetic mechanisms involved in tumor progression and, thereby, of normal cell growth, it is important to determine whether defects in one or more of these loci contribute functionally in the progression to malignancy in colorectal cancer and whether correction of any of these defects restores normal growth control in vitro and in vivo. To address this question, we have utilized the technique of microcell-mediated chromosome transfer to introduce normal human chromosomes 5, 17, and 18 individually into recipient colorectal cancer cells. Additionally, chromosome 15 was introduced into SW480 cells as an irrelevant control chromosome. While the introduction of chromosome 17 into the tumorigenic colorectal cell line SW480 yielded no viable clones, cell lines were established after the introduction of chromosomes 15, 5, and 18. Hybrids containing chromosome 18 are morphologically similar to the parental line, whereas those containing chromosome 5 are morphologically distinct from the parental cell line, being small, polygonal, and tightly packed. SW480-chromosome 5 hybrids are strongly suppressed for tumorigenicity, while SW480-chromosome 18 hybrids produce slowly growing tumors in some of the animals injected. Hybrids containing the introduced chromosome 18 but was significantly reduced in several of the tumor reconstitute cell lines. Introduction of chromosome 5 had little to no effect on responsiveness, whereas transfer ot chromosome 18 restored responsiveness to some degree. Our findings indicate that while multiple defects in tumor suppressor genes seem to be required for progression to the malignant state in colorectal cancer, correction of only a single defect can have significant effects in vivo and/or in vitro.

Alleles↗
PubMed1992

[Discrepancy between 123I-IMP SPECT and X-ray CT in chronic cerebrovascular disease].

The discrepancy between the low accumulation area (LAA) seen on 123I-IMP SPECT and the low density area (LDA) on X-ray CT was evaluated in 76 cases with chronic cerebrovascular disease. In 19 patients, LAA was larger than LDA beyond the vascular territory. Brain angiogram showed either obstruction or stenosis of the major arteries in as many as 59 percentages of this discrepancy group. In many patients of this group, cortical neurological symptoms were observed. In 37 patients in which the size of LAA was equal to that of LDA, abnormality of the major arteries was observed in only 7 percentages. These results indicated that the discrepancy mainly reflected the infarction due to irreversible ischemic change of perforate artery with the cortical low perfusion caused by the major artery disease. In some patients, the discrepancy was believed to show the remote effect caused by neurological pathway disturbance.

Adult↗
PubMed1992

[A longitudinal study of children with language delay at 3 years of age; later WPPSI and school attendance].

Ninety-four children (eighty-three boys and eleven girls), who were delayed in verbal expression (expressive language less than two-thirds of the standard for their chronological ages) at the age of three years, were evaluated for school attendance and intelligence at the age of six. The Yamada's Check List for Language Development and Wechsler Preschool and Primary Scale of Intelligence (WPPSI) were used to assess language problems and the intelligence quotient (IQ). Thirty children (32%) were delayed in verbal expression only, and sixty-four (68%) were delayed in both: verbal expression and comprehension were less than two-thirds of the standard for their chronological ages. Of children with delay in verbal expression only, 36% of them had low full-scale IQs (less than 70), and 27% had required special tutoring. Of children with delayed development of verbal expression and comprehension, 85% had low full-scale IQs, and 89% had required special tutoring or had attended schools for mentally retarded children. In expressive and comprehensive language delay, forty-one children avoided personal relations at the age of three years. Later thirty of these children were diagnosed as suffering from infantile autism. Poor mental outcome could be predicted by the delay of expressive and comprehensive language at the age of three years. The high prevalence of developmental disorders at later stages for the children in this study suggests the need for close monitoring of children with delayed language.

Child, Preschool↗
PubMed1991

Penta X syndrome: a case report with review of the literature.

We describe a 6 month-old girl with a 49, XX-XXX chromosome constitution. The patient had a characteristic round face, a low hairline, hypertelorism, epicanthus, a long philtrum, high-arched palate, short and webbed neck, small hands and feet, clinodactyly of the fifth fingers, overlapping toes, and separation between the first and the second toes. She also had atrial septal defect and patent ductus arteriosus complicated by myocarditis which exacerbated the course of her congestive heart failure. Psychomotor development was retarded with opisthotonoid posture, axial hypotonia, and with a borderline abnormal EEG. A densitometric, transmission analysis on X-linked polymorphic DNA-fragments of the Southern blots of the patient and the parents, using P20/MspI and pERT87-1/XmnI as probe/enzyme combinations, showed that the pentasomy X had resulted from 3 successive nondisjunctions at maternal meiosis. Clinical manifestations among 22 previously reported penta X syndrome patients are also reviewed.

Abnormalities, Multiple↗
PubMed1991

Chorionic villus sampling: analysis of fetal losses to delivery, placental pathology, and cervical microbiology.

A population of 1639 patients were seen for chorionic villus sampling (CVS). Embryonic death was identified at ultrasound in 5.3 per cent of patients. The number of patients undergoing CVS was 1551, with 1416 transcervical procedures and 135 transabdominal procedures. The most common indication for CVS was advanced maternal age. Spontaneous pregnancy losses identified by increased risk of pregnancy loss with increasing aspiration attempts. The total fetal loss for this population was 5.4 per cent with the pregnancy loss estimated due to procedure being 1.2 per cent. Analysis of placentae from patients having CVS and amniocentesis showed no differences. Microbiological assessment prior to CVS was similar to previous publications.

Adult↗
PubMed1991

Hypocalcemic focal seizures in a one-month-old infant of a mother with a low circulating level of vitamin D.

We present a case of a one-month-old infant with hypocalcemia and rickets, with symptoms of focal seizures. The ictal EEG showed left occipital spikes spreading over all of the left hemisphere. From the laboratory studies, we concluded that a low maternal circulating level of vitamin D would cause infantile hypocalcemia and rickets, while immature renal response to parathyroid hormone and transient hypoparathyroidism in infancy would induce hyperphosphatemia. Hypocalcemia may be an important factor in the cause of focal seizures which start even after the age of one month. Further, investigation of maternal vitamin D levels should be done in infantile hypocalcemia.

Adult↗
PubMed1991

[Usefulness of thallium-201 myocardial SPECT using dipyridamole infusion combined with low level exercise for the detection of the ischemic heart disease--comparison with SPECT images by maximum physical exercise in the same patients].

To evaluate the usefulness of thallium-201 myocardial SPECT using dipyridamole infusion combined with low level exercise (Dp-method) for the detection of the ischemic heart disease, we performed both Dp-method and maximum physical exercise SPECT (Ex-method) in the same 28 patients, and compared the results obtained by the two methods. In the visual evaluation, the detectability of each stenotic coronary territory by Dp-method tended to be higher than that by Ex-method (accuracy 71% vs 67%). The severity of the defect and the degree of the redistribution were higher by Dp-method than those by Ex-method. In the washout rate (WR) analysis in 14 angina pectoris patients, the detectability (accuracy) by Dp-method was significantly higher than that by Ex-method (86% vs 64%; p less than 0.05). In comparison of mean WR values in normal subjects (10 cases for Dp-method and other 8 cases for Ex-method), mean WR by Dp-method was as high as that by Ex-method and the deviation of WR value among subjects was very small. This was probably due to the effect of the low level exercise. These results suggested that Dp-method was more excellent than Ex-method in the evaluation of the ischemic heart disease, and was a useful method of the daily routine work. The incidence of chest symptom and the electrocardiographic ST-depression was as high by Dp-method as that by Ex-method. The filling defects in Dp-method were thought to be induced not only by the difference in the relative increase of the myocardial perfusion, but also by the myocardial ischemia.

Adult↗
PubMed1991

[Exacerbation of partial seizures in a case with heterotopic gray matter using antiepileptic drugs].

A two-year-old, right-handed girl was admitted to our hospital with a history of partial seizures. The first seizure, conjugated eye movements and head turning to the right, occurred at the age of 24 months. Later, she suffered from several seizures daily at the age of 34 months. At the age of 35 months, she was admitted to our hospital. On admission her neurological examination was normal. EEG showed a left parietal spike focus. A computed tomographic scan showed a small hyperdense area in the left parietal lobe without contrast enhancement. She was treated with carbamazepine (CBZ : 6 mg/kg/day). When seizures occurred several times within an hour, intravenous or rectal administration of diazepam (DZP : 0.3 mg/kg/dose) was added. However, she complained of sleepiness. The seizures occurred more frequently than before, 50 to 80 times daily, and became secondarily generalized. We thought that the exacerbation of the seizures resulted from the somnolence caused by DZP and CBZ. Consequently, these drugs were discontinued, and phenytoin was begun. She has since been free of seizures for two years. Approximately one year after the discontinuance of DZP and CBZ, heterotopic gray matter and abnormal gyri involving the left parieto-temporal lobe were found by magnetic resonance imaging (MRI). MRI is useful for detecting small heterotopic gray matter. To summarize this case, one should consider the possibility that excessive polytherapy induces seizures, particularly in patients with structural brain abnormalities such as heterotopic gray matter.

Brain↗
PubMed1991

Transhepatic portal vein catheterization for localization of insulinomas: a ten-year experience.

One of the most important factors in the management of insulinomas is the ability to localize the tumor accurately either before or during surgery. We prospectively carried out transhepatic portal venous sampling (THPVS) for tumor localization in 35 of 40 patients with organic hyperinsulinism during a 10-year period. In 32 patients who underwent THPVS and in whom a single tumor was subsequently identified surgically, the maximal insulin gradient was located in the vicinity of the tumor in 100% of cases. Specific regionalization of the tumor on the basis of the site of the maximal insulin gradient to one of three regions (the tail, the body/neck region, and the head/uncinate region) gave a sensitivity of 81% and a specificity of 91%. In contrast, the use of specific cutoff levels for the insulin gradient as a guide to the presence of a tumor in one of these three regions did not increase the accuracy, leading instead to a significant loss of sensitivity with no comparable increase in specificity. There were no major complications from the procedure in any patient. The initial use of computed tomographic/ultrasound scanning and selective angiography localized only 46% of tumors, whereas subsequent THPVS led to the accurate preoperative localization of 100% of all tumors submitted to surgery. Although the surgeon would have identified 81% of the tumors correctly at operation, in 19% (n = 6) he would have failed. Four tumors were in the uncinate and two were in the head. It seems that in patients with proved or established organic hyperinsulinism, THPVS may continue to be of value, if only to regionalize the tumor, especially those in the pancreatic head and uncinate process so as to preclude noncurative operations on the body and tail of the pancreas.

Adult↗
PubMed1990

The use of somatostatin analog in gastroenteropancreatic tumors other than carcinoid.

We have used the gastrinoma syndrome to examine the effects of SMS. Acutely, SMS decreased acid secretion and restored the BAO/MAO to normal in eight of eight patients. Basal and secretin-stimulated gastrin responses were suppressed but not normalized. Treatment for up to 2 years with SMS controlled symptoms, suppressed serum gastrin, and suppressed acid secretion. Treatment for 1 year or longer decreased tumor secretion of gastrin and diminished basal acid secretion, an effect that persisted for 48 hours after withdrawal of SMS. SMS treatment arrested progression of tumor growth only in patients in whom there was a reduction in gastrin and gastric acid secretion. In patients with metastatic disease who had high levels of gastrin, SMS treatment for 5 to 24 months did not inhibit tumor growth or decrease gastrin levels. In those patients in whom a reduction in the blood flow to liver tumors was shown angiographically, there was a progressive improvement in hormone secretion and in tumor size in the ensuing year of treatment, suggesting that a major target of SMS is that vascular supply of the tumors. Tumors shown to produce peptides other than gastrin, for example ACTH, were found to be markedly resistant to the action of SMS and continued to grow in an unbridled manner.

Adult↗
PubMed1990

A simple, combined fluorogenic and chromogenic method for the assay of proteases in gingival crevicular fluid.

Substrate impregnated paper discs were prepared using peptidyl derivatives of 7-amino-4-trifluoromethylcoumarin (AFC). After incubation with test solutions, the green, UV-induced fluorescence of AFC liberated by enzyme activity was distinguishable from the blue-violet fluorescence of the substrates. The AFC could then be coupled with p-dimethylaminocinnamaldehyde to form a colored Schiff base. Semi-quantiative assessments of disc fluorescence and color were made by comparison with AFC/substrate standards. Assays with discs impregnated with MeOSuc-Ala-Ala-Pro-Val-AFC, Z-Gly-Gly-Arg-AFC and Ala-Pro-AFC for elastase-, trypsin-, and dipeptidyl peptidase (DPP) IV-like activities respectively were evaluated using purified DPP IV and 100 eluates of crevicular fluid collected on filter paper strips from 10 gingivitis and periodontitis patients. The results showed that, within their working ranges, scores of disc fluorescence and color were reasonably accurate and reliable by comparison with enzyme activities measured in parallel quantitative fluorimetric assays with the same substrates. Using disc color, which was more sensitive than fluorescence, it was generally possible to measure all three enzyme activities in crevicular fluid samples from 5 periodontitis patients with varying degrees of gingival inflammation and pocketing. Disc color assays require no special apparatus and could be used for enzyme estimations in the clinical setting.

Amino Acid Sequence↗