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Biomedical subjects

S W Hong

Publications and source records attributed to S W Hong.

At least 55 records · Page 3Linked to original sources
PubMed1998

E-cadherin expression in thymomas.

For the purpose of investigating the pattern of E-cadherin (E-CD) expression in thymomas, 72 cases were immunostained using monoclonal antibody (HECD-1) and microwave-enhanced immunohistochemical method on formalin-fixed, paraffin-embedded tissue sections. The thymomas were classified according to modified Müller-Hermelink classification. The spindle-shaped, medullary type tumor epithelial cells in medullary (3 cases) and composite type (20 cases) thymomas rarely expressed E-CD except in focal areas showing microcystic change observed in 8 cases. Meanwhile, the cohesive epithelioid tumor cells in every case of well-differentiated thymic carcinomas (WDTC) (29 cases) expressed E-CD. The epithelial cells in cortical type (13 cases) expressed stronger E-CD compared with those of organoid type (7 cases). In cases of WDTC admixed with cortical type, we observed increasing expression of E-CD as the tumor epithelium forms cohesive sheets. We could not find any loss of E-CD expression in invasive foci of the 11 cases of high-staged WDTC examined. Since the results of our study show a strong correlation between E-CD expression and epithelioid morphology of the tumor, E-CD seems to play a major role as a morpho-regulatory factor rather than as a suppressor of invasion in organotypic thymomas.

Adolescent↗
PubMed1998

Soft tissue cover in compound and complicated tibial fractures using microvascular flaps.

This is a retrospective review of the use of microvascular flaps in the salvage of severely injured lower limb. From January 1992 to December 1994, we treated 10 patients using 10 microvascular flaps; 8 patients with Type III compound tibial fractures and 2 patients with infected implants following internal fixation of comminuted tibial fractures. The size of soft tissue defect ranged from 6 x 3 cm to 20 x 10 cm. One patient had a 6 cm bony defect. Soft tissue cover was achieved in 9 patients using microvascular muscle flaps with meshed split skin grafts and 1 patient using a scapula osteocutaneous flap. They were performed within 5 to 27 days following injury or removal of implants (mean 18 days). All the microvascular flaps were successful (100%). One re-exploration was performed. The mean period of hospitalization following microsurgical flap cover was 16.8 days. Eight out of 10 patients were followed up for a mean period of 48 months. All the 8 lower limbs were successfully salvaged. Three out of 8 patients (37.5%) had chronic osteomyelitis which required sequestrectomy and bone grafting. No amputation was necessary. Two patients required adjunctive cancellous bone grafting to accelerate bony union. Six out of 8 patients (75%) achieved bony union and full weight bearing capacity. The use of microvascular flap in achieving soft tissue cover plays an important role in the salvage of severely traumatized lower limb. Microvascular muscle flap is preferred when only soft tissue defect is present. Successful soft tissue cover facilitates secondary bone grafting procedures. Although the timing of surgery per se does not adversely affect the success rate of microvascular flaps, delayed soft tissue cover is associated with a high chronic infection rate (37.5%). An adequate surgical debridement is crucial in reducing the complication of deep infection.

Adult↗
PubMed1997

Evaluation of 515 expressed sequence tags obtained from guard cells of Brassica campestris.

As an attempt to examine the transcripts expressed in a single cell type and to unveil the physiology of guard cells at the molecular level, we generated 515 expressed sequence tags (ESTs) from a directional cDNA library constructed from guard-cell protoplasts of Brassica campestris L. ssp. pekinensis. A comparative analysis of the guard-cell ESTs against the National Center for Biotechnological Information non-redundant protein database revealed that 133 ESTs (26%) have significant similarity to protein coding sequences in the database. Among them were 35 clones related to genes that have not yet been identified in higher plants. Analysis of RNA gel blots of 14 database-matched clones revealed that five clones harbor the sequences for mRNAs expressed most abundantly in guard cells, one of them detecting an mRNA with highly preferential expression in guard cells. Functional categorization of the putatively identified guard-cell ESTs showed, when compared with maize leaf ESTs, that guard cells expressed a higher proportion of signal transduction components and a lower proportion of structural or photosynthetic genes, as is consistent with the roles of guard cells.

Brassica↗
PubMed1997

Identification of a receptor-like protein kinase gene rapidly induced by abscisic acid, dehydration, high salt, and cold treatments in Arabidopsis thaliana.

A cDNA clone for a receptor-like protein kinase gene (RPK1) was isolated from Arabidopsis thaliana. The clone is 1952 bp long with 1623 bp of an open reading frame encoding a peptide of 540 amino acids. The deduced peptide (RPK1) contains four distinctive domains characteristic of receptor kinases: (a) a putative amino-terminal signal sequence domain; (b) a domain with five extracellular leucine-rich repeat sequences; (c) a membrane-spanning domain; and (d) a cytoplasmic protein kinase domain that contains all of the 11 subdomains conserved among protein kinases. The RPK1 gene is expressed in flowers, stems, leaves, and roots. Expression of the RPK1 gene is induced within 1 h after treatment with abscisic acid (ABA). The gene is also rapidly induced by several environmental stresses such as dehydration, high salt, and low temperature, suggesting that the gene is involved in a general stress response. The dehydration-induced expression is not impaired in aba-1, abi1-1, abi2-1, and abi3-1 mutants, suggesting that the dehydration-induced expression of the RPK1 gene is ABA-independent. A possible role of this gene in the signal transduction pathway of ABA and the environmental stresses is discussed.

Abscisic Acid↗
PubMed1997

Pancreatic endocrine tumor admixed with a diffuse microcystic adenoma--a case report.

We report a case of pancreatic endocrine tumor admixed with a diffuse microcystic adenoma in a 67-year-old woman with a six months history of melena. Whipple's operation and near-total pancreatectomy were performed under the impression of a pancreatic cancer with duodenal invasion. The pancreas was enlarged and was entirely replaced by sponge-like tiny cysts, which were lined by a single layer of periodic acid Schiff positive cuboidal cells. Also encountered was a gray white solid area at the head portion which extended to the duodenum with an intraluminal polyp formation. The compact area was composed of solid and acinar structures of tumor cells, which showed a positive reaction for chromogranin A and neuron specific enolase, separated by delicate highly vascularized stroma. To the best of our knowledge, this is the first case report published with immunohistochemical studies to deal with a pancreatic endocrine tumor admixed with a diffuse microcystic adenoma.

Adenoma↗
PubMed1997

The effect of aflatoxin B1 on the expression of early response genes and transforming growth factor-alpha in CCl4 induced rat liver injury.

Aflatoxin B1 (AFB1), a fungal toxin produced by Aspergillus flavus, is known to be a possible hepatocarcinogen. But the molecular biologic changes which may occur following exposure to AFB1 are not known and thus the carcinogenesis is not yet understood. This study was performed to examine the expressions of c-myc, c-fos and TGF-alpha genes and to investigate the possible role of those molecular biologic changes in hepatic regeneration and in the development of hepatocellular carcinoma (HCC). Sprague-Dawley rats were divided into 3 groups: Carbon tetrachloride (CCl4) only was administered to group I, AFB1 only was administered to group II and a combination of AFB1 and CCl4 was administered to group III. The animals were sacrificed at 0.5, 1, 2, 6, 12, 24, 48, and 72 hours after treatment. In addition to the examination of the hematoxylin-eosin stained sections, hepatic regeneration and apoptosis were analyzed quantitatively by bromodeoxyuridine (BrdU)-anti-BrdU immunohistochemistry and TUNEL assay utilizing apoptosis kit, respectively. The hepatic expressions of c-myc, c-fos and transforming growth factor-alpha (TGF-alpha) were examined by immunohistochemistry and studied by Western blot. The number of BrdU labelled cells and the degree of necrosis/apoptosis were comparable among the different groups. Livers of the group II rats showed nearly normal histology without regeneration and necrosis/apoptosis. In groups I and III, the number of BrdU- labelled cells showed an increase at 48 hours after treatment, and the increment was significantly higher in group I than in group III. Most BrdU-labelled cells were mature hepatocytes in group I, whereas in group III they appeared to be less mature. In group I, apoptosis showed an increase at around 24 hours, but appeared in group III as early as 12 hours after treatment and persisted through 48 hours. The expression of c-myc and c-fos were also different between the experimental groups. The expression intensity of c-myc in group I was highest at 1 hour and decreased thereafter. In groups II and III, the expressions were much more intense than in group I, except at 1 hour, and the increased intensity persisted throughout the experiment. Group II in particular showed a peak intensity at 30 minutes and at 6 hours after treatment. In group I, c-fos was strongly expressed only at 24 hours, but in group III, there was progressively increased expression with peak intensity at 24 hours. TGF-alpha was expressed in similar intensities in all groups throughout the experiment. These results suggest that AFB1 may evoke an intense and protracted expression of c-myc, provocating the CCl4-induced necrosis of hepatocytes, and a prolonged expression of c-fos, including persistent signals for regeneration which in turn may activate the replication of immature cells. These findings will aid further investigation of molecular biologic and histologic characteristics of the hepatotoxic and hepatocarcinogenic mechanism of AFB1 in rats. And these results in rats, together with clinico-epidemiologic and molecular biologic investigations in humans and other animals, suggest that AFB1 may supply hepatocarcinogenic background in early exposure time in AFB1-contaminated areas of China and Korea.

Aflatoxin B1↗
PubMed1997

An information processing system for scheduling of nurse assignments by head nurses.

Implementation of the nurse scheduling task is a difficult problem for head nurses because it is a multi-period, multi-criteria decision-making problem with the condition that it meet the requirements of the patients, the hospital administration, and the staff nurses. There have been many research studies done using the following methods: cyclic method, mathematical modelling method, heuristic method and expert system approach. Without a theoretical review of head nurses' problem-solving processes, the limitations of inflexible computational modelling in comparison to the complex, real problem-solving process must be recognised. This research applies the cognitive scientific approach which uses protocol analysis and computer simulation. It will be used as basic data for a decision support system which will be constructed as a result of protocol analysis (collect data, analyse the head nurses' problem-solving process) and cognitive process simulation. Research in phase II will develop the following research lists: first; construction of databases including each nurse's major attributes as a data field, second; development of schedule optimising modules, and third; development of user interface for communication between head nurses and staff nurses using the system.

Cognitive Science↗
PubMed1996

Magnetic resonance imaging (MRI) of a cookie in comparison with time-lapse photographic analysis (TLPA) during baking process.

Magnetic Resonance Imaging (MRI) has been used to study the baking of a cookie. The structural and dynamic changes occurring during baking have been monitored, including changes in the internal moisture saturations and distribution. The images reveal the moisture distribution is initially uniform, and during baking a gradient in moisture develops from the interior to the edge. Changes in physical dimensions calculated from the data are consistent with those obtained from time-lapsed photography.

Cooking↗
PubMed1996

Interstitial mononuclear cell infiltrates in chronic rejection of the kidney and correlation with peripheral blood.

To investigate the characteristics of interstitial inflammatory cells and possible involvement of nudelta T cells, 16 renal allograft biopsies showing chronic rejection were stained by immunohistochemical method and correlated with the data of peripheral blood evaluated by flow cytometry. For immunophenotyping, fresh frozen sections were stained with monoclonal antibodies against CD3, CD4, CD8, CD68, CD56, TCRdelta1 and HLA DR. Paraffin embedded tissue was stained with CD45RO, CD20-Cy and CD68. Nine cases of nonspecific tubulointerstitial change and 4 cases of nonallograft tubulointerstitial nephritis were used as a control. Inflammatory infiltration was present in all cases studied. T cells predominated in the interstitium of chronic rejection and were followed by macrophages and B cells. The degree of interstitial infiltration of frozen section was not accordant with that of paraffin sections. Allografts with nonspecific tubulointerstitial changes or tubulointerstitial nephritis of native kidneys showed similar distribution pattern in terms of type and degree. However, the degree of infiltrate did not give any statistical significance among groups. The CD4/CD8 ratios in interstitial infiltrates were less than 1.0 in 6 cases and was not accordant with those of peripheral blood. Proportion of nudelta T cells increased over 10% in 2 cases in tissue and in 3 cases in peripheral blood. In 3 cases of chronic rejection in which both tissue and blood results were available, there was no concordance of CD4/CD8 or nudeltaT/CD3 between them. Tubular expression of HLA DR was, however, present only in 4 cases of chronic rejection. In conclusion, T lymphocytes were predominant regardless of diagnosis or disease activity. T lymphocyte subset did not give any suggestion as to the diagnosis or disease activity in chronic rejection. Furthermore nudelta T cells had only limited value. Lymphocytic subsets in peripheral blood would not be predictors of tissue destruction in chronic rejection.

Flow Cytometry↗
PubMed1995

Frequent in-frame length variations are found in the diverged simple repeat sequences of the protein-coding regions of two putative protein kinase genes of Brassica napus.

Two putative protein kinase cDNA clones were isolated from Brassica napus by screening with a putative protein kinase cDNA clone of Arabidopsis thaliana. The deduced amino acid sequences show a distinct modular composition, consisting of a possible protein kinase catalytic region at the amino terminus and a highly acidic region encoded from diverged simple repeat sequences at the carboxy terminus. Comparison of the nucleotide sequences encoding this acidic region revealed a high rate of in-frame length variation, while preserving the acidic characteristics. Similar variation is also found in the noncoding regions of these clones.

Amino Acid Sequence↗
PubMed1994

Functional complementation of a yeast vesicular transport mutation ypt1-1 by a Brassica napus cDNA clone encoding a small GTP-binding protein.

A cDNA clone (bra) encoding a small GTP-binding protein was isolated from Brassica napus by screening a root cDNA library with a degenerate oligonucleotide probe that corresponds to a highly conserved GTP-binding domain of the Ras superfamily. Sequence analysis shows that the clone contains an open reading frame of 219 amino acid residues with the estimated molecular mass of 24379 Da and this coding region contains all the conserved motifs of the Ras superfamily. The deduced amino acid sequence of the bra gene is most closely related to the Ypt/Rab family that functions in the vesicular transport (46% and 47% amino acid identity to the yeast Ypt1 and to the human Rab1, respectively) and is more distantly related to the other Ras-related families. The protein encoded by the bra gene, when expressed in Escherichia coli, shows the ability to bind GTP. Furthermore, when the bra gene is introduced into Saccharomyces cerevisiae under the regulation of the yeast GAL1 promoter, the gene can complement the temperature-sensitive yeast mutation ypt1-1 that has defects in vesicular transport function. The amino acid sequence similarity and the functional complementation of the yeast mutation suggest that this gene is likely to be involved in the vesicular transport in plants. Genomic Southern analysis shows that this gene is a member of a small gene family in Brassica napus.

Amino Acid Sequence↗
PubMed1993

Two putative protein kinases from Arabidopsis thaliana contain highly acidic domains.

Two cDNA clones (ASK1 and ASK2) for plant protein kinases were cloned from Arabidopsis thaliana by screening cDNA libraries with a degenerate oligonucleotide probe that corresponds to a highly conserved motif among protein kinases. Sequence analysis shows that the clones contain open reading frames that encode 41.2 kDa (ASK1) and 40.1 kDa (ASK2) proteins, respectively. These coding regions contain all the conserved motifs of protein kinases. Structural analysis of the coding regions revealed that the two protein kinase genes share high sequence similarity to each other (76.6% identity). The catalytic domain located in the amino terminal region is most similar to the calcium/calmodulin-dependent protein kinase subfamily (47.2% to 54.2% similarity) and the SNF1 kinase subfamily (48.1% to 53.3% similarity). However, the carboxy terminal regions contain distinctive stretches of 21 (ASK1) and 19 (ASK2) acidic amino acids. These clones are the first report of protein kinases with such acidic amino acid regions. The transcripts of both genes are most abundant in leaf but are also expressed in other organs. The expression of the two genes is highly affected by light regime.

Amino Acid Sequence↗
PubMed1991

Partial remission with transarterial embolization in a case of metastatic adrenal cortical carcinoma.

A case of metastatic adrenal cortical carcinoma in which partial remission was achieved with transarterial embolization is presented as probably the first reported case in the literature to date. A 29-year-old woman was admitted because of adrenal cortical carcinoma which had not responded to mitotane. A left adrenalectomy with segmentectomy of the involved liver had been done previously. Abdominal computerized tomography demonstrated multiple large metastatic tumors in the liver. Transarterial embolization with Gelfoam and 20 mCi of 131I-labeled lipiodol was performed and resulted in a decrease in tumor size and biochemical parameters. Transarterial embolization can be one of the therapeutic modalities for metastatic adrenal cortical carcinomas.

Adrenal Cortex Neoplasms↗
PubMed1991

Hodgkin's disease in a child with acute lymphoblastic leukemia.

Hodgkin's disease, manifested as a second malignant neoplasm in acute lymphoblastic leukemia, rarely occurs, with seventeen cases reported including this cases. We presented the clinical and pathological features of a nine-year-old male child with acute lymphoblastic leukemia in remission. He had cervical lymph node involvement 22 months after the diagnosis of leukemia as an initial presentation of Hodgkin's disease of mixed cellularity. A brief review of related literatures was also done.

Antineoplastic Agents↗
PubMed1990

The employment of ward opinion leaders for continuing education in the hospital.

Opinion leaders (OLs) are members within a social group with significant social influence over others. A guideline on urinary catheter care was introduced in three groups (A, B and C) of two randomly allocated wards. Two OLs per ward were identified by nurses in groups A and B, using a sociometric method. For education, inservice lectures for 30% of nurses and OLs tutorials for all nurses were used in group A; OLs tutorials in B, lectures in C and ward nurses were in turn responsible for educating new arrivals of student nurses. Before and after the education programme, the guideline's frequency of practice was assessed by surveying 30% of randomly selected nurses and by direct observation for incorrect practices. A student's quiz on the guideline was also conducted. For all three methods of measurement, the best results were in group A followed by B and C; and the differences for the three groups were significant (p less than 0.05). This indicates that continuing education in the hospital can be effectively conducted by the enlistment of ward OLs.

Education, Nursing, Continuing↗
PubMed1990

Defective response of natural killer activity to thyroxine in Graves' disease.

The effect of thyroxine (T4) on natural killer (NK) activity of peripheral blood lymphocytes (PBL) was investigated, using a 4-hr 51Cr release assay, in 18 patients with previously untreated Graves' disease and in 18 controls. NK activity in patients with Graves disease was not significantly different from that in the controls. Normal T4 (NT) and high T4 (HT) medium, free T4 concentrations in which were 1.01 and 16.3 ng/dl, respectively, were used to evaluate the effect of T4 on NK activity. In the controls, NK activity increased in the NT or HT medium compared with that in the control medium at effector to target cell (E:T) ratios of 25 : 1 and 50 : 1. NK activity in the Graves' disease patients, however, did not increase when either the NT or HT medium was used at E : T ratios of 25 : 1 and 50 : 1. These results suggest that patients with Graves' disease have a similar NK activity to the controls but have a defect in the peripheral blood lymphocytes to increase NK activity in response to T4.

Adult↗
PubMed1988

Location and biosynthetic regulation of endo-1,4-beta-glucanase in Aspergillus nidulans.

The location and biosynthetic regulation of endo-1,4-beta-glucanase were studied in Aspergillus nidulans. The enzyme was found to be extracellular, but low intracellular activity was also detected at the beginning of enzyme induction. The synthesis of the enzyme was regulated by carbon catabolite repression as well as specific induction. beta-1,4-Linked carbohydrates, such as carboxymethylcellulose, cellobiose and lactose, induced the enzyme synthesis, while 2-deoxyglucose and readily metabolizable substrates, such as glucose and glycerol, repressed it. Carbon catabolite repression could not be overcome by cAMP. Actinomycin D and cycloheximide completely inhibited the enzyme synthesis, which indicated the novo synthesis.

Aspergillus nidulans↗