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J S Ryu

Publications and source records attributed to J S Ryu.

At least 19 recordsLinked to original sources
PubMed2006

Efficacy of PET/CT in the accurate evaluation of primary colorectal carcinoma.

AIM: This study was performed to assess in the accurate evaluation of primary colorectal carcinoma using PET/CT. METHODS: One hundred patients with primary colorectal carcinoma were evaluated during 2004. All patients underwent PET/CT when their preoperative serum carcinoembryonic antigen was >or=10 ng/mL or when CT showed equivocal findings. The appropriateness of PET/CT-induced changes was noted by subsequent operative findings and follow-up. RESULTS: PET/CT more detected 15 intra-abdominal metastatic lesions than abdomino-pelvic CT scan. PET/CT showed true negative findings in 13 patients and false positive or negative findings in 10. Due to PET/CT results, management plans were altered in 27 patients; 9 had inter-modality changes, 10 received more extensive surgery, and 8 avoided unnecessary procedures. CONCLUSIONS: PET/CT altered management plan in 24% of patients with primary colorectal carcinoma in correct direction. These findings suggest that PET/CT should be considered a part of standard work up for preoperative evaluation in a subset of patients with colorectal carcinoma.

Adult↗
PubMed2006

Trichomonas vaginalis promotes apoptosis of human neutrophils by activating caspase-3 and reducing Mcl-1 expression.

Neutrophils are the predominant inflammatory cells found in the vaginal discharge of patients with Trichomonas vaginalis infection. However, it is not known whether neutrophil apoptosis is induced by live T. vaginalis. Therefore, we examined whether T. vaginalis can influence neutrophil apoptosis, and also whether caspase-3 and the Bcl-2 family members are involved in the apoptosis. Thus, human neutrophils were incubated with live T. vaginalis and neutrophil apoptosis was evaluated by Giemsa, annexin V-PI, and DiOC6 stainings. The neutrophil apoptosis was significantly higher in those incubated with T. vaginalis than in the control group. When trichomonads were pre-treated with mAb to AP65 (adhesin protein), or when trophozoites were separated from neutrophils using a Transwell chamber, neutrophil apoptosis was significantly reduced. The activation of caspase-3 was evident in neutrophils undergoing spontaneous apoptosis but was markedly enhanced during T. vaginalis-induced apoptosis. Moreover, the inhibition of caspase-3 effectively reduced T. vaginalis-induced apoptosis. Trichomonad-induced apoptosis was also associated with reduced expression of the neutrophil anti-apoptotic protein, Mcl-1. These results indicate that T. vaginalis alters Mcl-1 expression and caspase-3 activation, thereby inducing apoptosis of human neutrophils.

Animals↗
PubMed2005

Influence of exposure to electromagnetic field on the cardiovascular system.

1 We examined whether extremely low frequency electromagnetic fields (ELF-EMF) affect the basal level of cardiovascular parameters and influence of drugs acting on the sympathetic nervous system. 2 Male rats were exposed to sham control and EMF (60 Hz, 20 G) for 1 (MF-1) or 5 days (MF-5). We evaluated the alterations of blood pressure (BP), pulse pressure (PP), heart rate (HR), and the PR interval, QRS interval and QT interval on the electrocardiogram and dysrhythmic ratio in basal level and dysrhythmia induced by beta-adrenoceptor agonists. 3 In terms of the basal levels, there were no statistically significant differences among control, MF-1 and MF-5 in PR interval, QRS interval, mean BP, HR and PP. However, the QT interval, representing ventricular repolarization, was significantly reduced by MF-1 (P < 0.05). 4 (-)-Dobutamine (beta1-adrenoceptor-selective agonist)-induced tachycardia was significantly suppressed by ELF-EMF exposure in MF-1 for the increase in HR (DeltaHR), the decrease in QRS interval (DeltaQRS) and the decrease in QT (DeltaQT) interval. Adrenaline (nonselective beta-receptor agonist)-induced dysrhythmia was also significantly suppressed by ELF-EMF in MF-1 for the number of missing beats, the dysrhythmic ratio, and the increase in BP and PP. 5 These results indicated that 1-day exposure to ELF-EMF (60 Hz, 20 G) could suppress the increase in HR by affecting ventricular repolarization and may have a down-regulatory effect on responses of the cardiovascular system induced by sympathetic agonists.

Animals↗
PubMed2002

Regulation of plasminogen activator inhibitor (PAI)-1 expression in a human trophoblast cell line by glucocorticoid (GC) and transforming growth factor (TGF)-beta.

Plasminogen activator inhibitor (PAI)-1 plays a key role in the regulation of fibrinolysis and cellular invasion by virtue of suppression of plasminogen activator function. Excessive production of placental PAI-1 has been associated with aberrant periplacental fibrin deposition in pregnancies complicated by pre-eclampsia (PE) and intrauterine growth restriction (IUGR). In the current study we used HTR-8/SVneo cells and primary cultures of cytotrophoblasts as models for study of PAI-1 regulation by transforming growth factor (TGF)-beta, and dexamethasone (DEX), a synthetic glucocorticoid (GC). ELISA and Northern blotting assays revealed that DEX treatment significantly enhanced TGF-beta effects on PAI-1 protein and mRNA expression in HTR-8/SVneo cells and cytotrophoblasts. These effects were GC-specific in that DEX and cortisol, but not estradiol, progesterone or testosterone, augmented PAI-1 levels in TGF-beta-treated cells. Conversely, DEX and TGF-beta treatment suppressed PAI-2 levels in HTR-8/SVneo cells and did not affect PAI-2 levels in cytotrophoblasts. PAI-1 promoter assays revealed that TGF-beta, but not DEX, enhanced PAI-1 expression in HTR-8/SVneo cells through a transcriptional mechanism. These results suggest that GC and TGF-beta may alter fibrinolytic and invasive properties of trophoblasts through their effects on PAI-1 expression.

Blotting, Northern↗
PubMed2002

Phylogenetic relationships between the six superoxide dismutase proteins (FeSOD) of Trichomonas vaginalis and FeSOD6 genetic diversity.

The parasitic protozoan Trichomonas vaginalis is known to contain several types of Fe-containing superoxide dismutase proteins (FeSOD). Using three different methods of phylogenetic analysis, maximum parsimony (MP), neighbor joining (NJ), and maximum likelihood (ML) methods, we examined the phylogenetic relationships among the six FeSOD (FeSOD1-FeSOD6) based on their amino acid sequences. All the analyses consistently suggested that the six proteins formed a monophyletic group implying that they probably be originated from an ancestral protein form through repeated duplication events. Although MP tree was totally unresolved, the NJ and ML trees revealed that FeSOD6 placed the most basal position and thus emerged earlier than the other five gene types during the evolution of T. vaginalis. Phylogenetic relationships among the five remaining proteins were (FeSOD2, FeSOD3), (FeSOD4, (FeSOD1, FeSOD5)) although weakly supported in terms of bootstrapping values. In addition to this, we newly designed two PCR primer specifically amplifying full-length FeSOD6 gene and examined its genetic diversity among 12 T. vaginalis isolates from five countries and three continents. They had the same nucleotide sequences except those of three Korean isolates which showed one to three different nucleotides.

Amino Acid Sequence↗
PubMed2001

Organolanthanide-catalyzed intramolecular hydroamination/cyclization of amines tethered to 1,2-disubstituted alkenes.

[reaction: see text] This contribution reports the organolanthanide-catalyzed intramolecular hydroamination/cyclization of amines tethered to 1,2-disubstituted alkenes to afford the corresponding mono- and disubstituted pyrrolidines and piperidines by using coordinatively unsaturated complexes of the type (eta(5)-Me(5)C(5))(2)LnCH(TMS)(2) (Ln = La, Sm), [Me(2)Si(eta(5)-Me(4)C(5))(2)]NdCH(TMS)(2), [Et(2)Si(eta(5)-Me(4)C(5))(eta(5)-C(5)H(4))]NdCH(TMS)(2), and [Me(2)Si(eta(5)-Me(4)C(5))((t)()BuN)]LnE(TMS)(2) (Ln = Sm, Y, Yb, Lu; E = N, CH) as precatalysts. [Me(2)Si(eta(5)-Me(4)C(5))((t)BuN)]LnE(TMS)(2) mediates intramolecular hydroamination/cyclization of sterically demanding amino-olefins to afford disubstituted pyrrolidines in high diastereoselectivity (trans/cis = 16/1) and in good to excellent yield.

Alkenes↗
PubMed2001

NMDA receptor and NO mediate ET-1-induced behavioral and cardiovascular effects in periaqueductal gray matter of rats.

Endothelin-1 (ET-1), a novel and potent vasoconstrictor in blood vessel, is known to have some functions in the rat central nervous system (CNS). In order to investigate the central functions of ET-1, ET-1 was administered to the periaqueductal gray area (PAG) of anesthetized rats to induce barrel rolling and increase the arterial blood pressure (ABP). ET-1 had a modulatory effect on central cardiovascular and behavioral control. The selective N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 (3 micromol/kg, i.p.) blocked the ET-1 induced responses, and both the nitric oxide synthase (NOS) inhibitor L-NAME (N-nitro-L-arginine methylester 1 mmol/rat) and the nitric oxide (NO) scavenger hemoglobin (15 nmol/rat) had similar effects in reducing the ET-1 (10 pmol/rat)-induced behavioral changes and ABP elevation. However, NO donor sodium nitroprusside (SNP 10 microg, 1 microg/rat) decreased the ET-1 induced ABP elevation, and recovered the ET-1-induced barrel rolling effect that was reduced by MK-801. These results suggest that ET-1 might have neuromodulatory functions such as ABP elevation and barrel rolling induction in the PAG of the rats via the NMDA receptor and NO.

Animals↗
PubMed2001

Rhinosinusitis in transplant patients.

The control of perioperative infection has become more important to increase the success rate of organ transplantation. Thorough examination for occult infection prior to transplantation, careful postoperative monitoring and prompt treatment of infections are required. We reviewed the medical records of 278 patients who received organ transplantation over 4 years and analysed the clinical course of rhinosinusitis during the pre- and post-transplantation period. Thirty-two (11.5%) patients had rhinosinusitis. Nineteen were detected during preoperative examination and 13 were postoperative. Sinus surgery was performed in nine patients before organ transplantation. Ten out of 13 patients who had rhinosinusitis detected after transplantation required sinus surgery and three patients had invasive fungal infections. In the immunocompromised host, the clinical presentation of rhinosinusitis may be subtle, but the subsequent clinical course may be fulminant or even fatal. If the transplant recipient has unexplained fever or any nasal symptom, thorough evaluation with a high index of suspicion and prompt management are required.

Adolescent↗
PubMed2001

Pelioid-type hepatocellular carcinoma masquerading as a hepatic hemangioma on technetium-99m red blood cell scintigraphy.

Technetium-99m red blood cell (RBC) scintigraphy is a very specific method to differentiate a hemangioma from other hepatic masses. The authors report a case of hepatocellular carcinoma that showed a focal area of increased uptake on Tc-99m RBC SPECT in a 60-year-old man. Dynamic computed tomography and angiography revealed features of both hemangioma and hepatocellular carcinoma. Pathologic examination showed that the portion of the hepatocellular carcinoma that showed increased uptake on Tc-99m RBC scintigraphy had peliosis, which is the likely cause of the radiotracer avidity.

Carcinoma, Hepatocellular↗
PubMed2001

Simple and reliable preparation of pentavalent 99Tcm-dimercaptosuccinic acid at alkaline pH without oxygen bubbling.

We investigated a simple and reliable method for the preparation of 99Tcm-dimercaptosuccinic acid (99Tcm(V)-DMSA) without the addition of oxygen. The effect of pH, amount of reducing agent, and oxygen addition in the synthesis of 99Tcm(V)-DMSA were evaluated. At pH 9, we obtained a radiochemical yield of 95% +/- 1.2% within 10 min and a high stability until 7 h, with 92% +/- 1.5% radiochemical purity. However, at a pH lower than 9, the radiochemical yield was below 90% within 10 min, and a longer reaction time was needed to obtain a radiochemical yield above 90%. The addition of oxygen did not have an additional effect on the radiochemical yield or its stability at pH 9, whereas it increased the radiochemical yield of 99Tcm-(V)-DMSA at pH 7. It was noted that the smaller the amount of reducing agent used, the higher was the radiochemical yield obtained at pH 7. However, at pH 9, the radiochemical yield was not dependent on the amount of reducing agent. In conclusion, the synthesis of 99Tcm(V)-DMSA was more dependent on the pH of the reaction mixture than on the amount of reducing agent or the addition of oxygen. The adjustment of pH 9 was the easiest and most effective method for the synthesis of 99Tcm(V)-DMSA using a commercial kit for 99Tcm(III)-DMSA.

Drug Compounding↗
PubMed2001

Role of the proteasome in the regulation of fetal fibronectin secretion in human placenta.

The goal of the current study was to examine the role of the ubiquitin-proteasome system (UPS), a pathway of intracellular degradation, in the regulation of fetal fibronectin (FFN) expression in human placenta. Primary cultures of cytotrophoblasts (CTs) and placental mesenchymal cells (PMCs) were isolated from human term placentas and were maintained in serum-free medium (SFM) in the presence of inhibitors of proteasome-mediated degradation (e.g., MG132) as well as inhibitors of other proteases. Levels of secreted FFN and interleukin (IL)-8 in culture media were quantitated by enzyme-linked immunosorbent assay (ELISA), and cell viability was assessed by trypan blue exclusion. Intracellular levels of FFN and ubiquinated proteins were measured by Western blotting, and levels of fibronectin mRNA were determined following Northern blotting. We found that proteasome inhibitors (MG132, MG262, and PSI) potently suppressed levels of secreted FFN in cultures of CTs, but they not did affect levels of IL-8. Lysosomal, calpain, and serine protease inhibitors as well as the anti-inflammatory compound sulfasalazine did not markedly affect levels of secreted FFN in CT cultures. Proteasome inhibitors did not compromise cell viability during the initial 16-18 hours of treatment and did not affect intracellular levels of FFN protein or fibronectin mRNA. The efficacy of suppression of FFN in CT culture media by proteasome inhibitors reflected their effects on intracellular accumulation of ubiquinated proteins. By contrast, the presence of proteasome inhibitors did not alter levels of secreted FFN in cultures of PMCs. We conclude that inhibitors of proteasome-mediated degradation potently and specifically suppressed extracellular expression of FFN in CTs through a cell type-specific pathway that did not involve alterations in FFN synthesis. This suggests that accumulation of ubiquinated proteins in the presence of proteasome inhibitors blocks FFN secretion or promotes the extracellular degradation of FFN. This experimental paradigm will be useful for dissecting the role of the UPS in regulating CT function.

Adult↗
PubMed2001

Effect of iron on the virulence of Trichomonas vaginalis.

The role of iron was evaluated with respect to the virulence of Trichomonas vaginalis in mice. Iron-supplemented and iron-depleted Diamond's trypticase-yeast extract-maltose (TYM) media were prepared by adding 360 microM of ferrous sulfate and 100 microM of 2,2'-dipyridyl. Trophozoites cultivated from normal TYM and iron-supplemented TYM media produced subcutaneous abscesses; however, trichomonads grown in an iron-deficient TYM medium failed to produce any pathology. In addition to the increased virulence of trophozoites in mice, iron affects the level of adherence and the cytotoxicity of trichomonads to HeLa cells, which are significantly reduced in trophozoites grown in iron-deficient medium. In conclusion, it is suggested that under iron-depleted conditions such as that induced by 2,2'-dipyridyl the virulence of T. vaginalis is reduced.

Animals↗
PubMed2001

Two imported cases of cutaneous larva migrans.

Cutaneous larva migrans (CLM) is a rare serpiginous cutaneous eruption caused by accidental penetration and migration in the skin with infective larvae of nematode that normally do not have the human as their host. Although CLM has a worldwide distribution, the infection is most frequent in warmer climates. More recently, they have been increasingly imported from the tropics or subtropics by travelers. We experienced two patients who had pruritic serpiginous linear eruption in their skin for a few weeks after traveling to the endemic areas (Brazil and Thailand, respectively). After the treatment with albendazole, the skin lesions resolved with post-inflammatory hyperpigmentation. We report herein two cases of cutaneous larva migrans successfully treated with albendazole.

Adult↗
PubMed2000

Osmoprotective effect of glycine betaine on foreign protein production in hyperosmotic recombinant chinese hamster ovary cell cultures differs among cell lines.

When three recombinant Chinese hamster ovary (rCHO) cell lines, CHO/dhfr-B22-4, CS13-1.00*, and CS13-0.02*, were cultivated in hyperosmolar media resulting from NaCl addition, their specific foreign protein productivity increased with medium osmolality. However, due to a simultaneous suppression of cell growth at elevated osmolality, no enhancement in the maximum foreign protein titer was made in batch cultures. To test the feasibility of using glycine betaine, known as a strong osmoprotective compound, for improved foreign protein production in hyperosmotic rCHO cell cultures, hyperosmotic batch cultures were carried out in the presence of 15 mM glycine betaine. Glycine betaine was found to have a strong osmoprotective effect on all three rCHO cell lines. Inclusion of 15 mM glycine betaine in hyperosmolar medium enabled rCHO cell lines to grow at 557 to 573 mOsm/kg, whereas they could not grow in the absence of glycine betaine. However, effect of glycine betaine inclusion in hyperosmolar medium on foreign protein production differed among rCHO cell lines. CHO/dhfr-B22-4 cells retained enhanced specific human thrombopoietin (hTPO) productivity in the presence of glycine betaine, and thereby the maximum hTPO titer obtained at 573 mOsm/kg was increased by 72% over that obtained in the control culture with physiological osmolality (292 mOsm/kg). On the other hand, enhanced specific antibody productivity of CS13-1.00* and CS13-0.02* at elevated osmolality was decreased significantly in the presence of glycine betaine. As a result, the maximum antibody titer at 557 mOsm/kg was similar to that obtained in the control culture with physiological osmolality. The mRNA contents per cell determined by northern blot hybridization correlated with q in all three rCHO cell lines, indicating that transcriptional regulation is responsible in part for q enhancement at hyperosmolality in the absence as well as the presence of glycine betaine. Taken together, efficacy of the simultaneous use of hyperosmotic pressure and glycine betaine as a means to improve foreign protein production was variable among different rCHO cell lines.

Animals↗
PubMed2000

Applicability of carcinoembryonic antigen-specific monoclonal antibodies to radioimmunoguided surgery for human colorectal carcinoma.

Two carcinoembryonic antigen (CEA)-specific monoclonal antibodies (MAbs), PR1A3 and T84.66, were tested to determine whether they could accurately localize colorectal carcinoma and therefore be applicable in radioimmunoguided surgery (RIGS). Twenty-one tumors by three human colorectal carcinoma cell lines with various levels of CEA expression (KM-12c, C75, and Clone A) were successfully implanted in the intra-abdominal organs of 15 nude mice. The tumors was localized using a portable radioisotope detector (Neoprobe 1000) 48 h after injection of radiolabeled MAbs (10 mCi/mouse) when the precordial counts were <20 per 2 s. Histopathological identification of radiolabeled MAbs were also performed using immunohistochemistry and microautoradiography. Radioactivity counted on a portable radioisotope detector correlated well with that on a gamma counter. The distribution in the blood was significantly greater than in other organs (P < 0.001). Localization indices of the tumor in various organs was from 1.1 to 8.5 in the PR1A3-pretreated mice and 3.0 to 8.6 in the T84.66-pretreated mice. Silver grains and immune staining were distributed in the tumor cells of the PR1A3-pretreated mice, whereas they were in the necrotic debris as well as the tumor cells of the T84.66-pretreated mice. There were significantly more silver grains in the liver in the T84.66-pretreated mice than in the PR1A3-pretreated mice (P = 0.004). The sensitivity and specificity of tumor localization by RIGS were 71.4 and 91.4% in the PR1A3-pretreated mice, whereas they were 60 and 76% in the T84.66-pretreated mice. A study using specific anti-CEA MAbs suggested PR1A3 as an efficient immune probe for RIGS in colorectal carcinoma with a low rate of false-positive detection.

Animals↗
PubMed2000

Hepatobiliary scintigraphy in the assessment of biliary obstruction after hepatic resection with biliary-enteric anastomosis.

We investigated the usefulness of hepatobiliary scintigraphy (HBS) for diagnosing biliary obstruction after curative hepatic resection with biliary-enteric anastomosis. The study population consisted of 54 patients who underwent surgery for benign (n=18) or malignant (n=36) biliary disease. We analysed 68 technetium-99m DISIDA scintigrams which were performed at least 1 month after the surgery (median: 9 months). Final diagnosis was made by operative exploration, other invasive radiological studies or clinical and radiological follow-up for at least 6 months after the surgery. Diagnostic accuracy was analysed according to the pretest likelihood of biliary obstruction. There were two total and 15 segmental biliary obstructions. In patients with symptoms of biliary obstruction and abnormal liver function, HBS always allowed correct diagnosis (two instances of total obstruction, seven of segmental obstruction and seven of non-obstruction). Among the patients with nonspecific symptoms or isolated elevation of serum alkaline phosphatase, HBS diagnosed segmental biliary obstruction in seven of the eight instances, and non-obstruction in 22 of 23 instances. There were no cases of biliary obstruction and no false-positive results of HBS in 21 instances with no clinical signs or symptoms of biliary obstruction. The diagnostic sensitivity and specificity of HBS for biliary obstruction were 94% (16/17) and 97% (50/51), respectively. In conclusion, HBS is a highly accurate modality for the diagnosis of segmental biliary obstruction during long-term follow-up after hepatic resection with biliary-enteric anastomosis.

Biliary Tract Surgical Procedures↗
PubMed2000

Molecular identification of Paragonimus ohirai and P. westermani from Anhui Province, China.

Nucleotide sequences of the internal transcribed spacer 2 (ITS2) region were determined from seven adults of species Paragonimus collected from Jinde and Xiuning Counties, Anhui Province, China. Among these, the nucleotide sequence obtained from one Paragonimus adult (Jinde County) was identical to the ITS2 sequence of P. ohirai previously reported. In order to confirm the result, partial regions of mitochondrial cytochrome C oxidase I (COI) and NADH dehydrogenase 1 (ND1) from the putative P. ohirai sample were further sequenced. They showed a high level of similarity with those of P. ohirai, COI (99.7%) and ND1 (99.5%), supporting the result obtained from the ITS2. In addition to this, we designed P. ohirai- and P. westermani-specific primers (BDW and BD2OH) from ITS2 to identify P. westermani and P. ohirai easily and rapidly. After testing utility of the primers, they were applied to identify seven unidentified Paragonimus samples collected from Jinde and Xiuning Counties, China. All the examined samples showed P. westermani band pattern, and it was reconfirmed by sequencing their ITS2 regions that they are P. westermani. This result indicates that the two newly designed specific primers could be quite helpful for easily identifying P. westermani and P. ohirai, that most of Paragonimus in Jinde and Xiuning Counties consist of P. westermani, and that P. ohirai exists in Jinde County with minority.

Animals↗