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T S Kim

Publications and source records attributed to T S Kim.

At least 163 records · Page 9Linked to original sources
PubMed1997

Estimation of cardiorespiratory transfer under spontaneous breathing conditions: a theoretical study.

Using simulated noisy sequences of respiration and heart rate, we assessed the accuracy of the respiratory sinus arrhythmia transfer function (RSATF) estimation under three kinds of spontaneous breathing patterns: regular or tidal breathing, periodic breathing with apnea, and broadband breathing. Estimation employing the cross-power and autopower spectra of the simulated data produced RSATF estimates that were generally more variable than those computed with an autoregressive modeling approach. Variability and bias errors in the RSATF estimates became larger as respiratory bandwidth decreased when the breathing pattern changed from broadband to periodic to regular breathing. However, between frequencies of 0.1 and 0.3 Hz, these errors fell within 12% in all breathing patterns. Error in the RSATF estimates was only slightly increased, with reductions in data length to as low as 90 s. The results suggest the feasibility of obtaining accurate estimates of RSATF between 0.1 and 0.8 Hz from a wide variety of conditions, such as in different sleep-wake states where voluntary control of breathing is not possible and the ventilatory pattern may vary substantially.

Arrhythmia, Sinus↗
PubMed1997

Effects of repeated short versus single long episodes of focal ischemia on somatosensory evoked potentials and development of cerebral infarction in cats.

The effects of repeated short episodes of focal ischemia at 30-minute intervals or a single equivalent long episode of focal ischemia on neuronal function and development of cerebral infarction were compared using somatosensory evoked potential (SEP) recording and 2,3,5-triphenyltetrazolium chloride staining in a cat model. Seventeen cats underwent transorbital occlusion of the middle cerebral artery (MCA), using one of three procedures: sham-operation; single 1-hour occlusion of the MCA, followed by 3 hours of recirculation; or three 20-minute occlusions of the MCA at 30-minute intervals, followed by 3 hours of recirculation. Two of six cats in the single long-term occlusion group showed recovery of SEP, whereas all six cats in the repeated short-term occlusion group showed recovery of SEP at 3 hours after recirculation. All six cats in the single long-term occlusion group had cerebral infarction of various sizes, but only one cat in the repeated short-term occlusion group developed infarction. Repeated short episodes of focal ischemia are relatively less damaging than a single equivalent long episode of focal ischemia, even if the reperfusion interval is extended to 30 minutes.

Animals↗
PubMed1997

Changes in arterial blood PO2, PCO2, and pH during deep hypothermic circulatory arrest in adults.

Safe limits of time and temperature during sleep hypothermic circulatory arrest (DHCA) still remain controversial. Furthermore, continuous changes of PaO2, PaCO2, and pH have never been measured during DHCA in humans. Continuous intraarterial blood gas (CIABG) monitoring is a new technology allowing us to study chronological changes occurring due to metabolism during DHCA. When the patients' temperature reached 18 approximately 20 degrees C following establishment of cardiopulmonary bypass (CPB), circulatory arrest was initiated. After a 20-minute period of DHCA, reperfusion commenced with 18 degree C blood. We continuously monitored PaO2, PaCO2, and pH immediately before, during and following DHCA. Data was analyzed by Student's t-test. PaO2, PaCO2, and pH of pre- and 5 minutes post DHCA were not significantly different from each other. However, during DHCA, the PaO2 was significantly decreased from 229 +/- 34 to 30 +/- 23 mmHg at 20-minute intervals. But the PaCO2 increased significantly after 20 minutes of circulatory arrest from 34 +/- 5 to 42 +/- 6 mmHg. However, the pH did not change significantly over the 20-minute period. The PaO2 level after 20 minutes is much lower than before DHCA, it would be well tolerated in normothermic adults. The PO2 level in the brain may be even lower given its high metabolic rate. So measuring arterial PO2 continuously during DHCA may provide a surrogate method for determining maximum safe time under DHCA for adults.

Adult↗
PubMed1997

MR of childhood metachromatic leukodystrophy.

PURPOSE: To investigate the MR findings of childhood metachromatic leukodystrophy (MLD). METHODS: Nine MR imaging studies in seven children (five girls and two boys, 10 to 32 months old) with MLD were evaluated retrospectively for the extent and progression of white matter abnormalities and the presence of contrast enhancement. RESULTS: All seven cases showed symmetric, confluent high signal intensity on T2-weighted images in the periventricular white matter and centrum semiovale. A posterior predominance of white matter abnormalities was noted in all cases. Although initially spared from demyelination in all cases, in one case, the subcortical U fibers were later involved in demyelination of follow-up MR studies. Other sites of involvement were the genu (n = 5) and splenium (n = 6) of the corpus callosum, the posterior limbs of the internal capsule (n = 5), the descending pyramidal tracts (n = 4), the claustrum (n = 4), and the cerebral white matter (n = 2); diffuse brain atrophy was seen in two cases. No enhancement of the lesion was seen on any of the five postcontrast examinations. A "tigroid" pattern, previously described in cases of Pelizaeus-Merzbacher disease, was noted in the centrum semiovale in six cases. CONCLUSION: In late-infantile MLD, demyelination is more prominent in the occipital region. In addition to demyelination of the periventricular white matter, common manifestations include a "tigroid" pattern and involvement of the corpus callosum, the internal capsule, and the corticospinal tract.

Brain↗
PubMed1996

Promoter usage determines tissue specific responsiveness of the rat acetyl-CoA carboxylase gene.

The acetyl-CoA carboxylase gene contains two promoters, PI and PII which generate multiple mRNA forms. We have used the reverse transcription-polymerase chain reaction to investigate tissue specific promoter usage in rats either fed a standard chow diet, starved for 48 h, or starved and then refed a high carbohydrate, low fat diet. Expression of PII-generated mRNAs was seen in all tissues examined and was not dramatically changed by food removal or refeeding. PI-generated mRNAs were expressed at variable levels in a narrower range of tissues and were regulated by these dietary manipulations. Thus only the PI promoter is responsive to diet and the ability of a tissue to use this promoter determines whether it can alter fatty acid synthesis in response to nutritional challenges.

Acetyl-CoA Carboxylase↗
PubMed1996

High carbohydrate diet and starvation regulate lipogenic mRNA in rats in a tissue-specific manner.

We have previously shown that the effects of a high carbohydrate, fat-free diet and 24-h starvation on fatty acid synthesis in rats are tissue specific. In the present study we examine the tissue-specific pretranslational effects of high carbohydrate feeding, starvation and refeeding a high carbohydrate diet after starvation on the lipogenic pathway by measuring the levels of mRNA encoding acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) using Northern analysis. Additionally, we measured mRNA S14, a sequence tightly associated with lipogenesis. In rats fed the high carbohydrate diet, hepatic levels of the three mRNA were 3-5 fold higher than in controls. The level of S14 mRNA was doubled in epididymal fat, but other effects of this diet in adipose tissues were not significant. Expression in kidney, heart, lung and brain was not altered. Starvation significantly reduced the level of these mRNA in all tissues examined except brain. In liver, refeeding the high carbohydrate diet induced the expression of ACC, FAS and S14 mRNA 20-30 fold compared with the values found in 48-h starved animals. Hyperinduction of ACC and FAS, but not S14 mRNA expression was also observed in adipose tissues. The tissue-specific nature of these effects is consistent with previous measurements of fatty acid synthesis and confirm that this regulation occurs at the pretranslational level.

Acetyl-CoA Carboxylase↗
PubMed1996

Intradural extramedullary xanthoma of the spine: a rare lesion arising from the dura mater of the spine: case report.

OBJECTIVE AND IMPORTANCE: Xanthomatous tumors of the central nervous system are occasionally found in several unrelated diseases such as Hand-Schüller-Christian disease, Weber-Christian disease, histiocytosis X, malignant fibrous histiocytoma, and a complication of metabolic or storage diseases. However, a solitary xanthoma without systemic disease is rare. We present an unusual case of a solitary and benign xanthoma arising in the spinal leptomeninges without systemic diseases or metabolic abnormality, including a lipid profile. CLINICAL PRESENTATION: A 16-month-old male patient was admitted with a complaint of spastic paraparesis. His magnetic resonance images revealed an intradural extramedullary tumor that showed isosignal intensity on T1-weighted images and high signal intensity on T2-weighted images with homogenous gadolinium enhancement. INTERVENTION: The tumor arising from the spinal meninges was totally removed. Histological findings and immunochemical studies positive for CD68 and lysozyme stain showed abundant histiocytic cells with foamy cytoplasm. Negative S-100 protein in the immunohistochemical study and the absence of Birbeck granules on an electromicroscopic study excluded the possibility of Langerhan's histiocytosis. These findings corresponded to xanthoma. The patient had no abnormality of lipid metabolism or familial history of xanthoma. CONCLUSION: The patient improved enough to walk by himself 3 months after the operation.

Diagnosis, Differential↗
PubMed1996

The reproducibility and validity of furcation measurements using a pressure-calibrated probe.

The furcation involvement of 100 molars in 25 patients suffering from moderate to advanced periodontitis was investigated. The horizontal probing attachment level (PAL-H) within the furcations was assessed 2x within 2 weeks using the pressure-calibrated (0.25 N) flexible plastic universal explorer version of the TPS probe (TPS). To determine the measurement error of PAL-H assessments, the standard deviation of single measurements was calculated. The measurements were repeated using a colour-coded Nabers probe and compared to the TPS assessments. 253 furcations were evaluated (100 buccal, 47 lingual, 53 mesiolingual and 53 distolingual, respectively). For buccal, lingual, mesiolingual and distolingual furcations, the standard deviations were 0.486 mm, 0.598 mm, 0.846 mm, 1.039 mm, respectively. Measurement error was less in buccal and lingual furcations than in mesiolingual and distolingual sites (p < 0.005). The agreement of replicate measurements of furcation degrees was excellent for buccal and lingual furcations (weighted kappa [standard error] 0.824 [0.076] and 0.779 [0.107], respectively), but only moderate for mesiolingual and distolingual furcations (weighted kappa 0.688 [0.096] and 0.544 [0.101], respectively). Only in distolingual sites there was a significant (p < 0.025; paired t-test) underestimation of PAL-H by the TPS as compared to the Nabers probe. At all locations the TPS underestimated furcation degrees significantly (p < 0.1; Stuart-Maxwell's chi 2) as compared to Nabers probe. Measurement error of mesiolingual and distolingual furcations was significantly higher than of buccal or lingual sites. The reproducibility of PAL-H measurements in furcations using TPS is comparable to data published for scorings with colour-coded Nabers probes. Through and through furcations are likely to be underestimated by using the flexible plastic version of the TPS probe. Hence, it seems to be unsuitable for a proper assessment of the degree of furcation involvement.

Adult↗
PubMed1996

Statistical analysis of amputations and trends in Korea.

Epidemiological research on amputees is being continued extensively world wide, but there are different epidemiologic reports from country to country. This study undertakes an epidemiologic report of the medical records of amputees in Korea which has developed very rapidly, when compared with other countries. This study included 4258 amputees who either had an amputation and/or received prosthetic training at Yonsei University College of Medicine, Severance Hospital from January 1970 to June 1994. The most common cause of amputation was trauma (66.7%), and the second most common cause was peripheral vascular disease. While amputations due to infection or trauma were the most common in the 1950's, amputations due to peripheral vascular disease have gradually increased until they now make up 23.5% of all amputations in the 1990's. Lower limb amputation, more common than upper limb amputation, accounted for 68.7% of all amputation. Multiple amputation accounted for 9.3% of all amputations, and the occurrence rate of multiple amputation was relatively higher in cases of burn injuries, train accidents, frostbite, and Buerger's disease than in cases brought about by other causes. The various amputation causes change according to the circumstances of the times, as can be seen in this study.

Adolescent↗
PubMed1996

Involvement of the gallbladder in childhood metachromatic leukodystrophy: ultrasonographic findings.

The purpose of this study was to analyze the peculiar involvement of the gallbladder in childhood metachromatic leukodystrophy. Seven consecutive children (four boys, three girls; age range, 9 to 58 months old; mean age, 24.3 months) with biochemically confirmed metachromatic leukodystrophy were studied with abdominal ultrasonography. Four of them showed abnormal findings, such as diffuse thickening of the gallbladder wall (more than 3 mm thick), sludge-like echogenic material, or papillary polypoid ingrowth of inner wall obliterating the lumen. In childhood metachromatic leukodystrophy, the characteristic abnormality of the gallbladder on ultrasonography may serve as an ancillary diagnostic clue to supplement the clinical and MR imaging findings, facilitating the differential diagnosis from the other, similar leukodystrophies.

Child, Preschool↗
PubMed1995

Tissue-specific regulation of lipogenic mRNAs by thyroid hormone.

We have previously shown that triiodothyronine (T3) regulates rat fatty acid synthesis in a tissue specific manner. Here, we determined the effects of thyroid state on mRNAs encoding the lipogenic enzymes, acetyl CoA carboxylase (ACC) and fatty acid synthase (FAS). S14 mRNA, a sequence tightly associated with lipogenesis, was also measured. Levels of the three mRNA were 9-13-fold higher in hyper- than hypothyroid liver. Limited expression in kidney and heart was also increased by thyroid hormone. In brown adipose tissue, highest levels were recorded in hypothyroid animals. Thyroid state did not affect expression in lung and brain. All these changes are consistent with those previously measured in fatty acid synthesis. In white adipose tissue, mRNA expression was increased by hyperthyroidism. This increase may not be reflected in fatty acid synthesis, since we recently showed lipogenesis to be reduced under these circumstances. All three mRNAs responded rapidly to T3 in liver, but more slowly in kidney and fat. Thus, T3 regulates lipogenesis by altering levels of ACC and FAS mRNAs. S14 mRNA changes in parallel.

Acetyl-CoA Carboxylase↗
PubMed1995

Non random activation of endogenous interleukin-2, (IL-2), IL-2 receptor alpha and IL-2 receptor beta genes after transfection of mouse fibroblasts with a cDNA for the alpha chain of the human IL-2 receptor.

Mouse fibroblasts do not ordinarily express components for the interleukin-2 receptor (IL-2R alpha, beta, and gamma). An analysis of these cells by reverse transcription followed by polymerase chain reaction, however, indicates the presence of transcripts specific for the IL-2R beta and gamma genes. Transfection of the cDNA for the alpha chain of the human IL-2R into LTK- mouse fibroblast cell line (L3 cells) leads, in long-term cultures, to the formation of transcripts of endogenous mouse IL-2, IL-2R alpha and beta genes, as detected by Northern blotting. Based upon the results of the binding of 125I-labeled IL-2 to the transfected cells, three IL-2-binding proteins of 55 kDa, 65 kDa and 75 kDa were expressed by the transfected cells. The 65-kDa and 75-kDa proteins bound IL-2 in the presence of monoclonal antibodies for the IL-2R alpha chain. These polypeptides assembled to form high-affinity IL-2R, as shown by Scatchard binding analyses. The receptors were functionally active, since the expression of H-2k major histocompatibility complex antigens on the surface membranes of L3 cells was enhanced by exposing the cells to IL-2. Activation of the IL-2 gene was also observed in long-term cultures of L alpha beta cells, another LTK- transfectant expressing the human IL-2R alpha chain. This type of gene activation was not observed in LTK- fibroblasts transfected with cDNA for human IL-2 or IL-2R beta genes. In L3 and L alpha beta cells, transcription of the endogenous IL-2 gene was suppressed by cyclosporin A and enhanced by cycloheximide. These data may have implications for gene therapy of cancer cells.

Animals↗
PubMed1995

Antitumor activity of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2- isopropyl-1,3-dioxolane]platinum(II), a new platinum analogue, as an anticancer agent.

The in vitro and in vivo antitumor activity of a new antitumor platinum complex, cis-malonato[(4R, 5R)-4,5- bis(aminomethyl)-2-isopropyl-1,3-dioxolane]platinum(II) (SKI2053R, NSC D644591), were evaluated and compared with those of cisplatin (CDDP) and carboplatin (CBDCA) using murine tumors. SKI 2053R was highly active in vitro against both L1210 murine leukemia and its CDDP-resistant subline, L1210/DDP; the relative resistances were 20.0-, 14.5-, and 2.7-fold for CDDP, CBDCA, and SKI 2053R, respectively. SKI 2053R showed activity comparable with or superior to either CDDP or CBDCA in mice implanted with L1210. In mice implanted with L1210/DDP, as compared with CBDCA, SKI 2053R showed high values for the percentage of treated survivors relative to controls and for numbers of cured mice, whereas CDDP had virtually no activity. In mice implanted with P388, all three drugs were highly active, but the intensity of activity was shown to be ranked in the following order: SKI 2053R > CDDP > CBDCA. The antitumor activity of SKI 2053R against Lewis lung carcinoma was comparable with that of both CDDP and CBDCA. The antitumor activity of SKI 2053R was further investigated against two human tumor xenografts, KATO III (stomach adenocarcinoma) and WiDr (colon adenocarcinoma), implanted s.c. in nude mice and was compared with that of CDDP. In SKI 2053R-treated groups, the time required for a mean tumor weight of 1,000 mg was 33.1 days in KATO III xenografts and 35.0 days in WiDr xenografts as compared with 30.2 and 27.2 days in CDDP-treated groups, respectively. SKI 2053R achieved growth-inhibition rates comparable with those of CDDP against KATO III (65% versus 59%) and WiDr xenografts (64% versus 54%) on day 35. These results indicate that SKI 2053R is an attractive candidate for further development as a clinically useful anticancer drug.

Adenocarcinoma↗
PubMed1995

Immunization with interleukin-2/interferon-gamma double cytokine-secreting allogeneic fibroblasts prolongs the survival of mice with melanoma.

LM mouse fibroblasts (H-2k) were modified for the expression of (antibody-defined) melanoma-associated antigens (MAA) and the secretion of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) (RLBA-IL-2/IFN-gamma cells). The cell construct was tested for its immunogenic properties in C57BL/6 mice (H-2b) with B16 melanoma. The results indicated that the survival of mice injected with a mixture of B16 cells and the modified, double cytokine-secreting fibroblasts was significantly longer than that of mice injected with B16 cells and LM cells modified for the expression of MAA and the secretion of IL-2 or IFN-gamma alone (RLBA-IL-2 or RLBA-IFN-gamma cells). Both natural killer/lymphokine-activated killer (NK/LAK) cells and Lyt-2.2 + CTLs with anti-melanoma cytotoxic activities were predominant in mice immunized with the double cytokine-secreting cells. B16 melanoma cells persisted in mice treated with RLBA-IL-2 cells (B16-R3). The B16-R3 cells were resistant to anti-melanoma effector cells from mice immunized with RLBA-IL-2 cells. The recurrent melanoma cells were deficient in the expression of MHC class I determinants. Class I expression by B16-R3 cells was increased if they were incubated in medium conditioned by the growth of IFN-gamma-secreting RLBA-IL-2/IFN-gamma or RLBA-IFN-gamma cells. After incubation, the sensitivity of B16-R3 melanoma cells to immune-effector cells from mice immunized with RLBA-IL-2 cells was restored. The survival of mice bearing low MHC class I-expressing B16-R3 cells, treated RLBA-IL-2/IFN-gamma cells, was determined. The treated animals survived significantly longer than mice with B16-R3 melanoma treated with RLBA-IL-2 cells. Similar results were obtained for mice with B16-R3 melanoma treated with RLBA-IFN-gamma cells. We postulate that immunization of mice with IL-2/IFN-gamma double cytokine-secreting cells stimulated multiple anti-melanoma effector mechanisms. Analogous to the enhanced therapeutic anti-tumour effects of combination chemotherapy, it was likely that treatment with a cellular immunogen engineered to stimulate more than one effector mechanism resulted in the elimination of larger numbers of tumour cells than treatment with an immunogen that stimulated a single effector mechanism alone.

Animals↗
PubMed1995

Fibroblasts genetically engineered to secrete cytokines suppress tumor growth and induce antitumor immunity to a murine glioma in vivo.

The genes for interleukin (IL)-2, interferon (IFN)-gamma, or both IL-2 and IFN-gamma were introduced into a mouse fibroblast cell line (LM) expressing defined major histocompatibility complex determinants (H-2k). The cytokine-secreting cells were then co-transplanted with the Gl261 murine glioma cell line (H-2b) into syngeneic C57BL/6 mice that differed at the major histocompatibility complex from the cytokine-secreting cells. The period of survival of mice with glioma treated with IL-2- or IL-2/IFN-gamma-secreting allogeneic cells was significantly prolonged (P < 0.025) relative to the survival of mice receiving equivalent numbers of tumor cells alone or mice with glioma treated with nonsecreting fibroblast (LM) cells. Gliomas in the treated mice had an extensive lymphocytic cell infiltrate. Using a 51Cr release assay, the specific release of isotope from labeled Gl261 cells co-incubated with spleen from mice injected with the glioma cells and IL-2-secreting fibroblasts was higher (P < 0.001) than the release from glioma cells co-incubated with spleen cells from nonimmunized mice. Significantly higher levels of release (P < 0.005) were found in the group immunized with fibroblasts secreting both IL-2 and IFN-gamma. Based upon the effect of monoclonal antibodies for T-cell subsets on the antiglioma response, the immunity was mediated predominantly by natural killer/lymphokine-activated killer cells.

Animals↗
PubMed1995

Prolonged survival of mice with glioma injected intracerebrally with double cytokine-secreting cells.

A novel approach toward the treatment of glioma was developed in a murine model. The genes for both interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) were first transfected into a mouse fibroblast cell line that expresses defined major histocompatibility complex (MHC) determinants (H-2k). The double cytokine-secreting cells were then cotransplanted intracerebrally with the Gl261 murine glioma cell line into syngeneic C57BL/6 mice (H-2b) whose cells differed at the MHC from the cellular immunogen. The results indicate that the survival of mice with glioma injected with the cytokine-secreting allogeneic cells was significantly prolonged, relative to the survival of mice receiving equivalent numbers of glioma cells alone. Using a standard 51Cr-release assay, the specific release of isotope from labeled Gl261 cells coincubated with spleen cells from mice injected intracerebrally with the glioma cells and the cytokine-secreting fibroblasts was significantly higher than the release of isotope from glioma cells coincubated with spleen cells from nonimmunized mice. The cellular antiglioma response was mediated by natural killer/lymphokine-activated killer and Lyt-2.2+ (CD8+) cells. The increased survival of mice with glioma and the specific immunocytotoxic responses after immunization with fibroblasts modified to secrete both IL-2 and IFN-gamma indicate the potential of an immunotherapeutic approach to gliomas with cytokine-secreting cells.

Animals↗