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Biomedical subjects

J Kim

Publications and source records attributed to J Kim.

At least 325 records · Page 18Linked to original sources
PubMed2001

Ras/MAP kinase pathway is associated with the control of myotube formation but not myofibril assembly in quail myoblasts transformed with Rous sarcoma virus.

Tyrosine kinase activity of v-Src from Rous sarcoma virus (RSV) inhibits the differentiation of quail myoblasts. To clarify the inhibitory mechanism, we focused on the signaling pathways from v-Src. When the activation of the Ras/MAP (mitogen-activated protein) kinase pathway was inhibited by a dominant-negative mutant of Ras or PD98059, a specific inhibitor of p42 MAP kinase kinase, differentiation was restored; muscle specific proteins were expressed and myotubes formed even under active conditions of v-Src. Wortmannin, a specific inhibitor of phosphatidylinositol 3-kinase (P13-kinase), showed no effects on the inhibition by v-Src. These findings suggest that v-Src activates the Ras/MAP kinase signaling pathway, but not the P13-kinase pathway, and inhibits the differentiation. However, the myotubes derived from the dominant-negative Ras did not form actin fibers, suggesting that myofibril assembly is regulated by other pathway(s) from v-Src.

Animals↗
PubMed2001

Characterization of heterokaryons between skeletal myoblasts and somatic cells formed by fusion with HVJ (Sendai virus); effects on myogenic differentiation.

In skeletal myogenic differentiation, myoblasts fuse with myogenic cells spontaneously, but do not fuse with non-myogenic cells either in vivo or in vitro, suggesting that the fusion of myoblasts with non-myogenic cells is unsuitable for differentiation. To understand the inevitability of the fusion among myoblasts, we prepared heterokaryons in crosses between quail myoblasts transformed with a temperature-sensitive mutant of Rous sarcoma virus (QM-RSV cells) and rodent non-myogenic cells, such as tumor cells, fibroblasts, or neurogenic cells by HVJ (Sendai virus) and examined how myogenic differentiation was influenced in the prepared heterokaryons, focusing on myogenin expression and myofibril formation as markers of differentiation. When presumptive QM-RSV cells were fused with non-myogenic cells by HVJ and induced to differentiate, both myogenin expression and myofibril formation were suppressed. When myotubes of QM-RSV cells that had already expressed myogenin and formed myofibrils were fused with non-myogenic cells, both myogenin and myofibrils disappeared. Especially, fibrous structures of myofibrils were significantly lost and dots or aggregations of F-actin were formed within 24 hr after formation of heterokaryons. However, the fusion of presumptive or differentiated QM-RSV cells with rodent myoblasts did not disturb myogenin expression or myofibril formation. These results suggest that mutual fusion of myoblasts is indispensable for normal myogenic differentiation irrespective of the species, and that some factors inhibiting myogenic differentiation exist in the cytoplasm of non-myogenic cells, but not in myoblasts.

Animals↗
PubMed2001

Polymelia with two extra forelimbs at the right scapular region in a male Korean native calf.

In a male Korean native calf 14 days of age, polymelia (notomelia) was observed macroscopically and radiographically. External features included two normal forelimbs, two normal hindlimbs and two undeveloped extra forelimbs. The extra forelimbs were attached to the caudal regions of the right scapula and devoid of muscular tissues. In the extra forelimbs, a scapula-like bone formed a joint with the incompletely duplicated humerus. The humerus fused with the incompletely duplicated radius. The ulna, carpal bones, metacarpal bones and phalanges were completely duplicated. But one set of the duplicated carpal bones consisted of five bones: radial, accessory, fourth carpal, fused second and third carpal, and fused ulnar and intermediate carpal bones. The hoof and the rudimentary hoof of accessory digit were duplicated.

Animals↗
PubMed2001

Antimicrobial susceptibility of Actinobacillus pleuropneumoniae isolated from pigs in Korea using new standardized procedures.

The in vitro susceptibilities of 76 isolates of Actinobacillus pleuropneumoniae collected from pigs with pleuropneumonia were tested with 12 commonly used antimicrobial drugs by an agar dilution minimal inhibitory concentration procedure according to National Committee for Clinical Laboratory Standards (NCCLS) guidelines. Field isolates had low MICs for ceftiofur, danofloxacin and penicillin. No correlation of antimicrobial resistance was related to serotype.

Actinobacillus Infections↗
PubMed2001

Malignant thymic epithelial tumors: CT-pathologic correlation.

OBJECTIVE: The purpose of our study was to describe and compare the CT and pathologic findings of atypical thymoma and thymic carcinoma. MATERIALS AND METHODS: Twenty-seven consecutive patients (14 men, 13 women ranging in age from 22 to 77 years [mean age, 52 years]) with pathologically proven atypical thymoma (n = 9) and thymic carcinoma (n = 18) constituted the study population. The chest CT findings in each of the 27 patients were reviewed retrospectively in consensus by two chest radiologists. These findings were correlated with pathologic findings. RESULTS: The tumors were located in the anterior mediastinum, and most tumors had a lobulated margin (24/27, 89%). Atypical thymomas were significantly smaller (mean, 4.7 cm) than thymic carcinomas (mean, 7.2 cm) (p = 0.041) on CT. The findings of invasion of the great vessels, lymph node enlargement, extrathymic metastases, and phrenic nerve palsy were seen only in patients with thymic carcinoma. The frequencies of necrosis, intratumoral calcification, pleural effusion, pleural implants, pericardial effusion, and obliteration of the mediastinal fat plane were not significantly different between atypical thymomas and thymic carcinomas (p > 0.05). Various histologic subtypes were included in thymic carcinoma. The tumor necrosis and calcification seen on CT were confirmed at pathologic examination. CONCLUSION: When a large thymic tumor appears with invasion of the great vessels, lymph node enlargement, phrenic nerve palsy, or extrathymic metastases on CT, thymic carcinoma rather than atypical thymoma should be considered.

Adult↗
PubMed2001

Utilization of oral hypoglycemic agents in a drug-insured U.S. population.

OBJECTIVE: Clinical trials provide information regarding the safety and efficacy of medications used to manage type 2 diabetes but do not elucidate drug effectiveness in a typical managed care environment. The aim of this study was to characterize "real-world" drug utilization patterns from both a prescriber and a patient perspective. RESEARCH DESIGN AND METHODS: We conducted a retrospective analysis of a large administrative pharmacy claims database, using data on continuously pharmacy benefit-eligible members prescribed oral hypoglycemic agents (OHAs). RESULTS: The 12-month persistence rate for the OHA cohort was low, ranging from 31% for alpha-glucosidase inhibitors to 60% for metformin; compliance rates varied between 70 and 80%. During the first 12 months of therapy, 36% of the patients remaining on therapy at 12 months had one or more therapy modifications. The mean number of therapy changes increased with the length of patient follow-up, with more than half of all patients experiencing at least one therapy change over the duration of follow-up. CONCLUSIONS: These findings document the wide variation in utilization patterns associated with pharmacological management of type 2 diabetes, suggesting that opportunity exists to optimize its pharmacological management.

Carbamates↗
PubMed2001

Juxtaglomerular cell tumor of the kidney: a case report.

We report a case of renin-secreting juxtaglomerular cell tumor which developed in a hypertensive 47-yr-old Korean man. Presumptive clinical diagnosis was made before surgery based on the high level of plasma renin and the radiologic evidence of renal mass. Grossly, a round, bulging, well-encapsulated mass of 3 x 3 cm was located in the mid-portion of the right kidney. On microscopic examination, the tumor was composed of ovoid to polyhedral cells with bland nuclei, indistinct nucleoli and light eosinophilic cytoplasm. The immunostaining for renin showed strong positivity in the cytoplasm of tumor cells. The characteristic rhomboid shaped renin protogranules were observed in ultrastructural analysis.

Humans↗
PubMed2001

Insulin secretion and sensitivity during oral glucose tolerance test in Korean lean elderly women.

Impaired glucose tolerance (IGT) and type 2 diabetes including undiagnosed isolated postchallenge hyperglycemia (IPH) are common in the elderly. The aim of this study was to investigate the insulin secretion and sensitivity in Korean elderly lean diabetic women. Forty-one lean women aged 65-88 years took 2 hr oral glucose tolerance test (OGTT) and were stratified according to the WHO criteria (normal glucose tolerance [NGT], n=20; IGT, n=6; and type 2 diabetics, n=15 including seven IPH). HbA1c and fructosamine progressively increased from the NGT to the diabetic subjects (p=0.006 and p=0.001, respectively). Compared with subjects with NGT, the insulinogenic index, a marker of early insulin secretion and the AUC(ins), a marker of total insulin secretion, decreased significantly in diabetic group [0.53 (-0.44 -1.45) vs. 0.18 (0.00 -1.11), p=0.03 and 306+/-165 vs. 199+/-78 pmol/L, p=0.02 respectively]. A significant difference was found in the AUC(c-peptide) among each group (221+/-59 vs. 206+/-34 vs. 149+/-51 pmol/L, p=0.001 for each). The homeostasis model assessment of insulin resistance (HOMA-IR), a marker of insulin resistance, was not different among the groups. We conclude that compared with NGT subjects, elderly lean women with diabetes have impaired oral glucose-induced insulin secretion but have relatively preserved insulin sensitivity. This suggests that insulin resistance is not necessarily an essential component of Korean elderly lean diabetic women.

Aged↗
PubMed2001

Spinocerebellar ataxia type 6 and episodic ataxia type 2 in a Korean family.

Spinocerebellar ataxia type 6 (SCA6), episodic ataxia type 2 (EA2) and familial hemiplegic migraine (FHM) have been known as allelic disorders, which are caused by the alteration of the alpha1A voltage-dependent calcium channel subunit. Expansions of the CAG repeat in the CACNA1A gene on the short arm of the chromosome 19 induce SCA6, and point mutations in the same gene are responsible for EA2 and FHM. In recent studies, both SCA6 and EA2 have been concurrently found in families with 26 CAG repeats without previously reported point mutations either in coding sequences or in intron-exon junctions. We describe a Korean family with CAG26 repeats in the CACNA1A gene. Some of the affected family members had progressive ataxia typical of SCA6 whereas others had episodic vertigo responsive to acetazolamide typical of EA2. Our family support that SCA6 and EA2 are allelic disorders with a high phenotypic variability.

Adolescent↗
PubMed2001

Fatty acid patterns in gastric mucosa of stomach cancer patients.

omega6 and omega3 fatty acids are important cellular components and known to be involved in disease processes. However, few studies have focused on mucosa fatty acid in human gastric cancer. The purpose of this study was to investigate how fatty acid patterns of mucosa are altered in gastric cancer. Fatty acids were analyzed by gas chromatography and their relative compositions (%) were determined and evaluated both in mucosa total-fatty acids and in phospholipid-fatty acids in paired cancerous and non-cancerous gastric cancer tissues (n = 18). The level of arachidonic acid (20:4omega6, AA) appeared significantly higher both in phospholipid-fatty acids (p < 0.05) and in total-fatty acids (p < 0.001) in cancerous mucosa compared to non-cancerous mucosa. The omega6/omega3 fatty acid ratio of phospholipid-fatty acids was also significantly higher in cancerous mucosa. The higher level of AA in cancerous tissue can be partially explained by the higher ratio of 20:4omega 6/20:3omega6 (desaturation index) and the lower ratio of 22:4omega6/20:4 omega6 (elongation index). The change in the relative composition of arachidonic acid may influence the production of prostaglandins and related metabolites, which regulate cell differentiation and proliferation. The findings of this study with respect to fatty acid changes, especially in terms of arachidonic acid metabolism, may be of relevance in the understanding of the roles of specific fatty acids and possibly of eicosanoids in gastric cancer.

Adult↗
PubMed2001

Loss of rapid phonological recoding in reading Hanja, the logographic script of Korean.

The role that recent experience has in the processing of Korean Hanja characters was investigated in two masked priming experiments. Two groups of Korean native speakers that differed in their recent exposure to Hanja were asked to name single Hanja characters (targets) that were immediately preceded by masked presentations of the same characters (repetition priming), Hanja characters that were homophones of the target (homophone priming), or unrelated characters (baseline). The results showed that the group that had been less recently exposed made more errors and were slower than the group that had been the more recently exposed. Furthermore, there was no character homophone priming for the less recently exposed group, although they did show a robust repetition priming effect. On the other hand, the more recently exposed group showed both strong character repetition and homophone priming effects. We suggest that regular exposure to characters supports their rapid and automatic processing. It is argued that the different patterns of priming for the two groups were due to how rapidly the orthographic and phonological information of the prime could be resolved.

Adult↗
PubMed2001

Microbiological, sensory, and electronic nose evaluation of yellowfin tuna under various storage conditions.

Microbiological assessment, sensory evaluation, and electronic nose (AromaScan) analysis were performed on yellowfin tuna stored at 0, 4, 10, and 22 degrees C for 0, 1, 3, 5, and 9 days. Fish color, texture, appearance, and odor were evaluated by a trained sensory panel, while aroma-odor properties were evaluated using an AromaScan. Bacterial enumeration was performed using plate count agar containing 1.5% NaCl. Tuna fillets stored at 22 degrees C for 3 days or longer had a bacterial load of over 10(7) CFU/g and were rated not acceptable for consumption (grade C) by the sensory panel. Tuna fillets stored at 4 degrees C for 9 days or 10 degrees C for over 5 days were rated as grade C products and also had a bacterial load of over 10(7) CFU/g. The change in fish quality as determined by AromaScan followed increases in microbiological counts in tuna fillets, indicating that bacterial load can serve as a useful and objective indicator of gross spoilage. Electronic nose devices can be used in conjunction with microbial counts and sensory panels to evaluate the degree of decomposition in tuna during storage.

Animals↗
PubMed2001

Pain at the site of tarsal tunnel incision due to neuroma of the posterior branch of the saphenous nerve.

The authors conducted a retrospective review of 16 patients who presented with the complaint of pain at the incision site after tarsal tunnel decompression. Specifically, the pain was located at the proximal aspect of the tarsal tunnel decompression scar. The mean duration of pain was 21 months (range, 6 to 34 months). The pain was eliminated by a block of the distal saphenous nerve, demonstrating that the pain was due to a neuroma of this nerve. The pain was treated by resection of the distal saphenous nerve in the distal leg and implantation of the proximal end of this nerve into the soleus muscle. At a mean of 18.5 months after surgery (range, 6 to 33 months), excellent relief of pain was achieved in 76% of cases and good relief of pain in 24% of cases.

Decompression, Surgical↗
PubMed2001

Field measurements of internal pressurization in Phragmites australis (Poaceae) and implications for regulation of methane emissions in a midlatitude prairie wetland.

Emergent aquatic macrophytes in vegetated wetlands provide routes for methane (CH(4)) transport from sites of production in oxygen-poor sediments, where CH(4) concentrations are relatively high, to the atmosphere, which typically has much lower CH(4) concentrations. Transport can occur through aerenchymatous tissue via simple diffusion. Recently, the importance of convective throughflow (i.e., mass transport of gases through plants driven by pressure gradients) in enhancing gas transport has been demonstrated in several genera (e.g., Nuphar, Nymphaea, Nelumbo, Typha, and Phragmites). This study was conducted to elucidate the governing plant-mediated gas transport mechanisms in a midlatitude prairie wetland and to determine both their diel and seasonal variations and the importance of environmental controlling factors. Pressures inside culms of the two dominant emergent aquatic macrophytes (Scirpus acutus and Phragmites australis) were measured directly throughout the growing season and on selected days in midseason. Supporting measurements included solar radiation, air temperature, relative humidity, and windspeed. Results indicated pressures inside green healthy culms of Phragmites were above atmospheric pressure by up to 1650 Pa during the day. At night culm pressures were at or slightly above atmospheric. No pressurization was detected in Scirpus. Highest pressures in Phragmites occurred during midseason when biomass and foliage area index were at their maxima (920 g/m(2) and 2.8, respectively). High internal pressures also coincided with periods of high solar radiation (>500 W/m(2)), high temperature (>20°C), and low relative humidity (<60%). Periods of high internal pressures also coincided with periods of high CH(4) efflux from the wetland as measured in concomitant studies. Convective throughflow driven by internal pressure gradients in Phragmites thus explains much of the diel variation in methane efflux previously reported from this wetland.

Journal Article↗
PubMed2001

A meshless numerical technique for physically based real time medical simulations.

This work introduces, for the first time, a meshless modeling technique, the method of finite spheres, for physically based, real time rendering of soft tissues in medical simulations. The technique is conceptually similar to the traditional finite element techniques. However, while the finite element techniques requires a slow mesh generation process, this new technique has significant potential for multimodal medical simulations of the future since it does not use a mesh. Several examples are presented showing the effectiveness of the scheme.

Computer Graphics↗
PubMed2001

Chromosome polysomy and histological characteristics in oral premalignant lesions.

Head and neck tumorigenesis has been postulated to represent a multistep process driven by the accumulation of carcinogen-induced genetic changes throughout the exposed tissue field. To better explore this genetic instability process at the tissue level, 59 regions within 26 biopsy tissue specimens from individuals with oral leukoplakia have been subjected to chromosome 9 in situ hybridization analysis, and the degree of chromosome instability was related to known clinical/pathological parameters associated with tumor risk. Whereas chromosome indices were similar between high-risk lesion sites and low-risk lesion sites, high-risk lesions showed higher levels of chromosome polysomy than did low-risk sites [median PIs (polysomy indices), 2.1 versus 1.4, respectively]. Similarly, dysplastic regions showed significantly higher chromosome polysomy levels than hyperplastic regions (median PIs, 2.4 versus 1.5, respectively). Interestingly, however, hyperplastic regions in the same biopsy as dysplastic regions showed two-times higher polysomy levels than those in biopsies without dysplasia (median PIs, 2.6 versus 1.3, respectively), suggesting that chromosome polysomy determinations provide a field measurement for the degree of ongoing genetic insult. Finally, chromosome polysomy tended to persist or increase in the superficial epithelial layers in regions showing koilocytosis, whereas their frequency decreased in nonkoilocytotic regions, suggesting that epigenetic factors may serve to perpetuate the levels of genetically unstable cells in the epithelium. These results provide direct support for the field cancerization process and suggest that measurements of genetic instability might provide additional biological information beyond histology and lesion site characteristics in the assessment of head and neck cancer risk.

Adult↗