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Biomedical subjects

K O Kim

Publications and source records attributed to K O Kim.

11 recordsLinked to original sources
PubMed2006

Endoscopic submucosal resection with double ligation technique for treatment of small rectal carcinoid tumors.

BACKGROUND AND STUDY AIMS: It is difficult to achieve complete endoscopic resection of rectal carcinoid tumors without any procedure-related complications. In this study, we evaluated the efficacy and safety of endoscopic submucosal resection with double ligation (ESMR-DL) for the treatment of small rectal carcinoid tumors. PATIENTS AND METHODS: Eleven rectal carcinoid tumors (in 11 patients) were resected by ESMR-DL between November 2001 and April 2004, using a conventional single-channel endoscope with an attached band-ligator device. The lesion was aspirated into the ligator device and an elastic band was placed around the base; a detachable snare was then used to ligate the stalk below the elastic band; and snare resection was performed above the elastic band. The resected specimens were examined with respect to size, histological atypia, depth of invasion, and the histological appearance of the resection margins. RESULTS: All the lesions were excised completely without any complications. There was no tumor invasion beyond the submucosal layer and there was no evidence of atypia in any of the specimens. Tumor diameter varied from 2.0 mm to 10.0 mm (average 6.2 mm). None of the 11 specimens showed histopathological evidence of tumor involvement at the resection margins. There were no immediate or late complications (bleeding or perforation) after ESMR-DL. There was no local recurrence and there were no distant metastases in any patients during the mean follow-up period of 18 months. CONCLUSION: Endoscopic submucosal resection with double ligation is a useful and safe method for the treatment of small rectal carcinoid tumors.

Carcinoid Tumor↗
PubMed2003

Positioning internal jugular venous catheters using the right third intercostal space in children.

BACKGROUND: Central venous catheters are used for pressure measurement, and drug and fluid therapy in children. Several reports have described serious complications related to catheter positioning. We evaluated the possibility of using the right third intercostal space as an anatomic landmark for determining the optimal insertion depth of a central venous catheter from the right internal jugular vein. METHODS: The distance between the skin puncture site and the right third intercostal space (SK-ICS) was measured in 83 children. The catheter was inserted to a depth equal to the measured distance. Postoperatively, the distance between the catheter tip and the radiographic junction of the superior vena cava and the right atrium was measured. This was defined as the optimal catheter length, which placed the catheter tip at the SVC/RA junction (SK-SVC/RA). RESULTS: A significant correlation was found between the SK-ICS and SK-SVC/RA (regression equation: SK-SVC/RA = 0.35 + 0.98 x SK-ICS, r2 = 0.8554). Based on the data obtained, a simple formula, SK-ICS-1 (cm), predicted that a CVC would be positioned above the RA in 98.8% of patients. CONCLUSIONS: Using the right third intercostal space as an anatomic landmark allows positioning of the catheter tip in the SVC near to but not in the RA in children.

Catheterization, Central Venous↗
PubMed2001

Pairing of forskolin and KCl increases differentiation of immortalized hippocampal neurons in a CREB Serine 133 phosphorylation-dependent and extracellular-regulated protein kinase-independent manner.

Although cAMP response element binding protein (CREB)- and extracellular-regulated protein kinase (ERK)-mediated pathways have been linked to each other in neuronal differentiation, involvement of these in hippocampal neuronal cell line has not been defined. Using an immortalized hippocampal cell line, HiB5, we have tried a pairing of forskolin with KCl depolarization, which acts as an ERK and CREB kinase activator in hippocampal neurons, to investigate if an activation of ERK and phosphorylation of CREB at the critical regulatory site, serine 133 might be coupled in differentiation. Differentiation toward a neuronal phenotype was synergistically and markedly increased by the pairing of forskolin and KCl depolarization. The synergistic effect was accompanied by an increase in phosphorylation of CREB Ser-133, but not phosphorylation of ERK, and was not inhibited by MEK inhibitor, PD98059. These findings indicate that phosphorylation of the transcriptional factor CREB may function to facilitate differentiation of HiB5 cells.

Animals↗
PubMed2001

Hydrogen peroxide triggers the expression of Fas/FasL in astrocytoma cell lines and augments apoptosis.

Fas expression increases in perinecrotic areas of glioblastoma. In this study the up-regulation of Fas/FasL by oxidative stress was shown. H(2)O(2) exposure increased Fas expression in two astrocytoma cell lines and cells became sensitive to agonistic anti-Fas antibody. FasL was up-regulated in astrocytoma cells. Apoptosis of Molt-4 cells was augmented by astrocytoma cells pretreated with H(2)O(2). Our findings suggest up-regulation of Fas in astrocytoma cells may lead them to be sensitive to apoptosis when cells are in oxidative stress. Whereas, the up-regulation of FasL may render astrocytoma cells cytotoxic to neighboring brain tissues and infiltrating immune cells.

Apoptosis↗
PubMed2000

c-Fos expression by dopaminergic receptor activation in rat hippocampal neurons.

While dopamine is likely to modulate hippocampal synaptic plasticity, there has been little information about how dopamine affects synaptic transmission in the hippocampus. The expression of IEGs including c-fos has been associated with late phase LTP in the CA1 region of the hippocampus. The induction of c-fos by dopaminergic receptor activation in the rat hippocampus was investigated by using semiquantitative RT-PCR and immunocytochemistry. The hippocampal slices which were not treated with dopamine showed little expression of c-fos mRNA. However, the induction of c-fos mRNA was detected as early as 5 min after dopamine treatment, peaked at 60 min, and remained elevated 5 h after treatment. Temporal profiles of increases in c-fos mRNA by R(+)-SKF-38393 (50 microM) and forskolin (50 microM) were similar to that of dopamine. An increase in [cAMP] was observed in dopamine-, SKF-, or forskolin-treated hippocampal slices. By immunocytochemical studies, control hippocampal cells showed little expression of c-Fos immunoreactivity. However, when cells were treated with dopamine, an increase in the expression of c-Fos immunoreactivity was observed after treatment for 2 h. The treatment of hippocampal neurons with R(+)-SKF38393 (50 microM) or forskolin (50 microM) also induced a significant increase in c-Fos expression. These results indicate that the dopamine D1 receptor-mediated cAMP dependent pathway is associated with the expression of c-Fos in the hippocampal neurons. These data are consistent with the possible role of endogenous dopamine on synaptic plasticity via the regulation of gene expression. Furthermore, these results imply that dopamine might control the process of memory storage in the hippocampus through gene expression.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1999

Polyethylene oxide additive-entrapped polyvinyl chloride as a new blood bag material.

Until now, most widely used blood bag material has been a plasticized polyvinyl chloride (PVC) because it has many desirable properties as a blood bag material. One of main concerns of using plasticized PVC as a blood bag material is the toxicity of the plasticizers that are leached out of the material. We tried to solve this problem by the addition of polyethylene oxide (PEO)-containing amphiphilic block copolymers as additives in the PVC. The PEO additives may play two roles: they can act as nontoxic plasticizers to PVC, and they can also act as blood-compatible surface modifiers. In this study, PEO additive-entrapped PVC films were prepared by the addition (up to 30 wt%) of PEO-alkyl carbon block copolymers or PEO-polypropylene oxide (PPO)-PEO triblock copolymers with different PEO chain lengths in the PVC. The prepared PEO additive-containing PVC films were characterized by the measurements of water contact angle, Fourier transform IR spectroscopy in the attenuated total reflectance mode, mechanical properties (tensile strength and elongation at break), water absorption, and stability of the PEO additives entrapped in the films. It was observed that the PEO additive-entrapped PVC films were flexible and transparent. It seems that the PEO additives are surface active, resulting in the considerable change of surface characteristics without a significant change of the mechanical properties of the films compared to the control PVC without any additives or a commercial blood bag. The adhesion of platelets on the film surfaces was significantly reduced by the addition of PEO additives. It seems that 10% addition of PEO additives is enough for the suppression of platelet adhesion on the surfaces. This study demonstrated that the use of PEO-containing block copolymers as additives to the PVC can be a feasible approach to prepare a new type of blood bag.

Biocompatible Materials↗
PubMed1999

Aging process is accompanied by increase of transglutaminase C.

Crosslinking has been suggested as one of the mechanisms involved in the aging process. Among the various random or enzyme-mediated crosslinking reactions, transglutaminase (TGase)-catalyzed crosslinking activity has been proposed for its possible involvement in cell proliferation, differentiation, carcinogenesis, programmed death, and aging. Moreover, recent findings of TGase C as a putative signal transducer and cell cycle regulator has renewed interest in the study of TGase C in relation to aging phenomena. The ubiquitous presence of TGase C compared to the organ-specific localization of other types of TGases has attracted special attention as a cellular aging device. In the present investigation for in vitro studies, we have compared the pattern of TGase C in young and old human red blood cells, separated by density differentiation, and in early and late-passage or hydrogen peroxide-treated human primary fibroblasts. For in vivo study, we monitored the age-dependent changes of TGase C in the liver and brain tissues of 4, 12, 18, and 24-month-old Sprague-Dawley rats. We obtained evidence that both the activity and protein levels of TGase C were high in old RBC and late-passage or hydrogen peroxide-treated fibroblasts. Similar findings were seen in liver and brain tissue such as age-dependent increases in TGase activity and protein level in an organ-specific pattern. These data suggest that TGase C might play an active role in the cellular process with age.

Adult↗
PubMed1981

Effect of starvation on tissues from the young of four species, with emphasis on the number and diameter of skeletal muscular fibers.

Young rats, rabbits, guinea pigs, and hamsters were decreased in body weight by 39, 45, 34, and 35%, respectively, by a total deprivation of food for 3, 15, 4, and 4.5 days, respectively. The weight of the heart, liver, and kidneys from each of the four species (with the excepetion of the kidneys from the guinea pig) decreased significantly in the starved animals. After starvation in all four species, 0 to 15% of the original weight of the epididymal and perirenal fat pads remained. The effect of total starvation on the weight of skeletal muscles differed for the same muscle in different species and among the three muscles studied within a species. Starvation caused weight losses in the following muscles from the rat, rabbit, guinea pig, and hamster, respectively: soleus, 15, 8, 14, and 30% plantaris, 23, 54, 41 and 24%; biceps brachii, 27, 52, 42, and 29%. The significant loss of weight in the plantaris and biceps brachii muscles from rabbits and guinea pigs were caused by large decreases in the diameter of the fibers, with no change in the number of fibers. Soleus and plantaris muscles from hamsters decreased in weight by a reduction in fiber diameters but no change in the number of fibers; the weight of biceps brachii decreased by a reduction in fiber number only. A reduction in the number of fibers occurred in all muscles from starved rats; the diameter of the fibers was reduced in the plantaris and biceps brachii muscles. No structural damage to the fibers due to starvation was observed under the light microscope in any muscle from the four species.

Animals↗
PubMed1980

Changes in skeletal muscle cellularity in starved and refed young rats.

1. All food was withdrawn from male weanling rats until a 40% loss of body-weight was attained. Another group of animals was treated similarly and then refed a stock diet until the original body-weight was attained. 2. The body-weight loss caused a significant reduction in the weight of the heart, kidney, liver and epididymal fat pads. Refeeding produced a return to the control weight of the heart and kidney, an increase in the weight of the liver and a deficit in the weight of the epididymal fat pads. 3. Body-weight loss caused a decrease in the weight of the three different muscles studied, and in the number and diameter of the fibres in each muscle. Refeeding restored the weight and cellularity of two of the three muscles to that of the control animals. The soleus muscle was heavier in the refed animals when compared to controls due to an increased fibre diameter. 4. It is concluded that the decrease in the number and diameter of muscle fibres during starvation in the rat can be restored on refeeding a stock diet.

Adipose Tissue↗