Biomedical subjects

S Ryu

Publications and source records attributed to S Ryu.

At least 37 records · Page 2Linked to original sources

PubMed2000

Inhibitory effects of collagen on the PCR for detection of Clostridium perfringens.

It is essential to identify specific food components that inhibit PCR in order to increase the sensitivity of the PCR method for rapid detection of pathogens contaminating a food. We found that collagen, a major component of several foods, inhibited PCR. The inhibitory action of collagen on PCR could be partially reversed by adjusting the concentration of magnesium ion in the reaction mixture and by the use of various DNA extraction methods to remove the collagen from the DNA. Also, the source of thermostable DNA polymerase was affected by the presence of collagen. These results suggest the need to optimize the extraction and assay conditions for rapid detection of enterotoxigenic Clostridium perfringens by PCR with respect to the kind of food being analyzed.

Clostridium perfringens↗

PubMed2000

Hematologic toxic reaction to radiation therapy adjuvant to autologous peripheral blood stem cell transplantation for recurrent or refractory Hodgkin disease.

PURPOSE: To evaluate the hematologic toxic reaction to external-beam radiation therapy after high-dose chemotherapy with peripheral blood stem cell (PBSC) support in patients with Hodgkin disease. MATERIALS AND METHODS: A retrospective study of 30 cases of Hodgkin disease in patients who underwent high-dose carmustine, etoposide, and cyclophosphamide chemotherapy with PBSC support was performed. Thirteen patients underwent radiation therapy (28.8-39.0 Gy) a median of 45 days after PBSC repeat infusion. RESULTS: Radiation therapy was delivered as planned, without interruption, in all patients. Five patients developed thrombocytopenia (one with grade 1 thrombocytopenia; two, grade 2; and two, grade 3) and included three with progressive disease prior to radiation therapy and two with a history of prior irradiation. None developed a bleeding complication or required transfusion support. Five patients who underwent irradiation had thrombocytopenia (three with grade 1 and two with grade 2) 100 days after PBSC repeat infusion, compared with three patients (two with grade 1 and one with grade 3) who did not undergo posttransplantation irradiation. At the most recent follow-up, no patient without evidence of disease had a platelet count of less than 100 x 10(9)/L. CONCLUSION: External-beam radiation therapy was well tolerated in the posttransplantation setting in patients with Hodgkin disease. Thrombocytopenia was common but was not related to clinical complications.

Adolescent↗

PubMed2000

Ventricular arrhythmias with left bundle branch block pattern and inferior axis: assessment of their mechanisms on the basis of response to ATP, nicorandil and verapamil.

The present study investigated the mechanism of ventricular arrhythmias showing left bundle branch block (LBBB) pattern with an inferior axis. The effects of 3 drugs, adenosine triphosphate (ATP), nicorandil and verapamil, were evaluated in 17 patients. ATP suppressed the arrhythmias in 14 patients and nicorandil suppressed them in 8 of those 14. Verapamil suppressed 5 of the 6 ATP-nicorandil-sensitive arrhythmias. Four patients with ATP- or nicorandil-sensitive arrhythmias were not sensitive to verapamil. On the other hand, 3 of the ATP-insensitive arrhythmias were sensitive to neither nicorandil nor verapamil. The QT intervals and QTc were shortened by nicorandil in 5 of the 6 patients who were sensitive to all 3 drugs. One mechanism of suppression by nicorandil could be related to less Ca++ entering the myocardium, which would decrease the duration of the action potential as indicated by the shortened QT intervals. The results suggest that the mechanism of some ventricular arrhythmias is related to triggered activity. Arrhythmias that are sensitive to ATP or nicorandil, but not to verapamil, may be caused by abnormal automaticity. On the other hand, arrhythmias that are insensitive to all 3 drugs might be related to reentry. The features of ventricular arrhythmias with LBBB pattern and inferior axis differ and therefore the causative mechanisms are not the same.

Adenosine Triphosphate↗

PubMed2000

3'UTR polymorphisms in the NRAMP1 gene are associated with susceptibility to tuberculosis in Koreans.

SETTING: Korea University and the Korean Institute of Tuberculosis, Seoul, Korea. OBJECTIVE: To determine whether polymorphisms in the 3' untranslated region (UTR) of the NRAMP1 gene are associated with susceptibility to tuberculosis in Koreans. DESIGN: A case-control study design was used to compare the frequency of 3'UTR of NRAMP1 among 192 tuberculosis patients and 192 healthy individuals. All of the samples were diagnosed by X-ray, smear and culture tests between 1998 and 1999 in the Cross of Lorraine Clinic at the Korean Institute of Tuberculosis. RESULTS: A significant association was found between the Korean tuberculosis patients and polymorphisms in the 3'UTR of the NRAMP1 gene (odds ratio [OR] 1.845; 95% confidence interval [CI] 1.097-3.104; chi2 = 5.424; P = 0.020). CONCLUSION: This study showed that genetic variations in the human NRAMP1 gene are associated with susceptibility to smear-positive tuberculosis in Korean patients. The 3'UTR variant allele associated with susceptibility to tuberculosis is very uncommon in Caucasians, but is present in Koreans and West Africans. These observations may explain in part why African Americans and Koreans have greater susceptibility to tuberculosis than Caucasians.

Alleles↗

PubMed1999

Strong intracellular and negative peripheral expression of fibronectin in tumor cells contribute to invasion and metastasis in papillary thyroid carcinoma.

The intracellular and stromal expression of fibronectin (FN) in invading and central parts of papillary thyroid carcinomas with/without lymph node (LN) metastasis (54 metastasizing cases, 52 non-metastasizing cases) were examined immunohistochemically. The intracellular expression of FN in tumor cells in invading parts was stronger than that in central parts in most cases (79/106 cases, 74.5%). In invading parts, negative stromal FN was frequently found at the periphery of the tumor in cases with extracapsular soft tissue invasion (26/37 cases). Tumor cells in invading parts in metastatic cases were significantly more likely to be negative for stromal FN at the periphery of the tumor than those in non-metastatic cases (P < 0.0001). The strong intracellular and negative stromal FN at the periphery of the tumor in invading parts were associated with invasion and metastasis in papillary thyroid carcinoma. These results suggest that these distinctive characteristics of FN may be useful for understanding invasion and metastasis in vivo.

Adult↗

PubMed1999

Purification of Mlc and analysis of its effects on the pts expression in Escherichia coli.

Products of the pts operon of Escherichia coli have multiple physiological roles such as sugar transport, and the operon is controlled by two promoters, P0 and P1. Expression of the pts P0 promoter that is increased during growth in the presence of glucose is also activated by cAMP receptor protein.cAMP. Based on the existence of a sequence that has a high similarity with the known Mlc binding site in the promoter, the effects of the Mlc protein on the pts P0 promoter expression were studied. In vivo transcription assays using wild type and mlc-negative E. coli strains grown in the presence and absence of glucose indicate that Mlc negatively regulates expression of the P0 promoter, and Mlc-dependent repression is relieved by glucose in the growth medium. In vitro transcription assay using purified recombinant Mlc showed that Mlc repressed transcription from the P0 but did not affect the activity of the P1. DNase I footprinting experiments revealed that a Mlc binding site was located around +1 to +25 of the promoter and that Mlc inhibited the binding of RNA polymerase to the P0 promoter. Cells overexpressing Mlc showed a very slow fermentation rate compared with the wild type when grown in the presence of various phosphoenolpyruvate-carbohydrate phosphotransferase system sugars but few differences in the presence of non-phosphoenolpyruvate-carbohydrate phosphotransferase system sugars except maltose. These results suggest that the pts operon is one of major targets for the negative regulation by Mlc, and thus Mlc regulates the utilization of various sugars as well as glucose in E. coli. The possibility that the inducer of Mlc may not be sugar or its derivative but an unknown factor is proposed to explain the Mlc induction mechanism by various sugars.

Bacterial Proteins↗

PubMed1999

Purification of transcription cofactor complex CRSP.

Transcription of protein coding genes in metazoans involves the concerted action of enhancer binding proteins and the RNA polymerase II apparatus. The cross talk between these two classes of transcription factors is mediated by an elaborate set of cofactor complexes. For the activation of transcription by the promoter specificity protein 1 (Sp1), TATA binding protein-associated factors in the TFIID complex originally were identified as necessary coactivators, but the identity of additional cofactors required for activated transcription was unknown. Recently, we have reported the isolation and properties of a cofactor complex, CRSP (cofactor required for Sp1), which functions in conjunction with the TATA binding protein-associated factors to promote efficient activation of transcription by Sp1. CRSP contains unique subunits as well as polypeptides that are shared with other cofactor complexes. Here, we report a detailed purification protocol for the isolation of CRSP from human HeLa cells. Our purification strategy takes advantage of the ability of CRSP to bind Ni2+-nitrilotriacetic acid-agarose resin as well as other conventional chromatographic resins. We also describe a streamlined purification protocol that allows a more rapid and efficient means to isolate active CRSP.

Chromatography, Affinity↗

PubMed1999

The transcriptional cofactor complex CRSP is required for activity of the enhancer-binding protein Sp1.

Activation of gene transcription in metazoans is a multistep process that is triggered by factors that recognize transcriptional enhancer sites in DNA. These factors work with co-activators to direct transcriptional initiation by the RNA polymerase II apparatus. One class of co-activator, the TAF(II) subunits of transcription factor TFIID, can serve as targets of activators and as proteins that recognize core promoter sequences necessary for transcription initiation. Transcriptional activation by enhancer-binding factors such as Sp1 requires TFIID, but the identity of other necessary cofactors has remained unknown. Here we describe a new human factor, CRSP, that is required together with the TAF(II)s for transcriptional activation by Sp1. Purification of CRSP identifies a complex of approximate relative molecular mass 700,000 (M(r) approximately 700K) that contains nine subunits with M(r) values ranging from 33K to 200K. Cloning of genes encoding CRSP subunits reveals that CRSP33 is a homologue of the yeast mediator subunit Med7, whereas CRSP150 contains a domain conserved in yeast mediator subunit Rgr1. CRSP p200 is identical to the nuclear hormone-receptor co-activator subunit TRIP2/PBP. CRSPs 34, 77 and 130 are new proteins, but the amino terminus of CRSP70 is homologous to elongation factor TFIIS. Immunodepletion studies confirm that these subunits have an essential cofactor function. The presence of common subunits in distinct cofactor complexes suggests a combinatorial mechanism of co-activator assembly during transcriptional activation.

Antibodies↗

PubMed1999

Impact of hypertension guideline implementation on blood pressure control and drug use in primary care clinics.

BACKGROUND: A worsening of blood pressure control has occurred in the 1990s despite the availability of sophisticated technologic, pharmacologic, and educational advances applicable to hypertension care. Clinical guidelines that are intended to improve hypertension care by making specific recommendations on drug use, frequency of follow-up care, and target levels of blood pressure have been developed. METHODS: The Institute for Clinical Systems Integration's (ICSI's; Minneapolis) Hypertension Treatment Guideline was developed in 1994 and is updated annually. This study employed a quasi-experimental, before-and-after design at two medical groups to assess changes in the care provided to patients 18 years of age and older with identified hypertension (International Classification of Diseases-9 codes 401.0, 401.1, or 401.9). RESULTS: Among adults with hypertension, the proportion meeting the blood pressure goal of < 140/90 mm Hg increased from 36.8% (of 685 patients) preguideline to 50.3% (of 928 patients) postguideline (chi-square = 29.4, p < 0.001); the mean arterial pressure decreased from 102.7 mm Hg to 99.4 mm Hg (t = 5.45, p < 0.001). Cohort analysis of patients enrolled at both points in time confirmed these findings and showed an increase in the number of office visits from 5.4 to 6.7 visits per patient per year after guideline implementation (F = 10.9, p = 0.001). The use of a guideline-recommended medication for treatment of blood pressure was 35.9% preguideline and 36.2% postguideline. CONCLUSIONS: Implementation of a hypertension treatment guideline in primary care clinics was related to significantly improved hypertension control. Identification, tracking, and active outreach to patients with hypertension were used by all clinics.

Adult↗

PubMed1999

Resection and permanent I-125 brachytherapy without whole brain irradiation for solitary brain metastasis from non-small cell lung carcinoma.

We assessed a treatment plan of local therapy (resection and placement of permanent low dose-rate I-125 seeds) without whole brain irradiation in 15 patients with solitary brain metastasis (SBM) from primary non-small cell lung cancer between January, 1991 and May, 1996. Thirteen lesions were confirmed as solitary by MRI scan, and 2 patients had CT scan only. With median follow up of 14 months, 3 patients remain alive at 6, 33, and 62 months post-resection. Median survival is 14 months for all patients and 26 months for patients with SBM as the only site of disease. Five tumors failed in the brain: 2 solitary recurrences adjacent to the site of SBM, 2 multiple metastases outside the primary site, and 1 multiple recurrence including the primary site. No failures were seen with SBM <2.5 cm. Only 2 of 13 patients with SBM confirmed with MRI experienced relapses elsewhere in the brain. Recurrence rates both adjacent and outside the area of the initial brain lesion are similar to studies employing resection plus whole brain irradiation (WBI), and the patient is spared the acute and potential late toxicity of WBI. This approach may be considered for selected patients with solitary brain metastases (SBMs), although further experience with larger patient numbers is needed.

Brachytherapy↗

PubMed1999

The meaning of public health nursing: creating 24 hour care in a community in Japan.

This case study describes the strategies and activities of public health nurses to increase the availability of services in a municipality of 36,000 and to transform community attitudes so that those needing services would feel free to use them. Strategies and activities are seen in the context of Japan, Minakuchi Town and the leadership of the chief public health nurse. Practicing in partnership with members of the community, strategies of public health nurses include technical activities (conducting needs assessment and framing program alternatives) and information sharing and health education (e.g. 75 meetings organized with health promoters for residents in the districts of the town). On the basis of the results of Minakuchi Town, viewed as an example of expert public health nursing practice, a general model for public health nursing practice is presented.

Adult↗

PubMed1999

In-vitro synergy of paromomycin with metronidazole alone or metronidazole plus hydroxymetronidazole against Helicobacter pylori.

The in-vitro activities of paromomycin and metronidazole alone or paromomycin and metronidazole plus hydroxymetronidazole (2:1 ratio) were studied against 19 Helicobacter pylori isolates using an in-vitro chequerboard technique. Partial synergy was demonstrated for the majority of isolates (11/19) for both combinations tested. When hydroxymetronidazole was added to the parent compound, the number of metronidazole-sensitive isolates demonstrating synergy increased to 5/12, compared with 1/12 for the combination that did not include the metabolite. In metronidazole-resistant isolates there was a shift from an additive effect to partial synergy for the combination containing hydroxymetronidazole. The in-vitro activity of paromomycin and the synergic effect that is achieved in combination with metronidazole and hydroxymetronidazole render paromomycin suitable for further investigation as a treatment option for H. pylori infection.

Anti-Bacterial Agents↗

PubMed1999

Bactericidal activity and postantibiotic effect of levofloxacin against anaerobes.

The bactericidal activity and postantibiotic effect (PAE) of levofloxacin against nine anaerobes were determined. Levofloxacin at concentrations of the MIC and twice the MIC was bactericidal at 24 h to five of nine and nine of nine strains, respectively. The PAE of levofloxacin following a 2-h exposure ranged from 0.06 to 2.88 h.

Anti-Infective Agents↗

PubMed1999

Precocious estrus and reproductive ability induced by PG 600 in prepuberal gilts.

A total of 29 SPF Large White prepuberal gilts (mean age 152 days at treatment) were examined for estrous and ovulatory responses after PG 600 treatment. After treatment, 85.2% of the gilts showed standing estrus within 6 days. Whereas the treatment-to-estrus interval and duration were 3.7 and 1.9 days respectively. As ovulation occurred on Day 5 to 6, appropriate timing of artificial insemination would be about 4 days after treatment. Fertility of gilts revealed to be excellent, giving rise to a high percentage of normal embryos, 85.3%. Meanwhile, development and growth of fetuses were mostly normal. Other reproductive performances recorded were: mean litter size 6.8; mean birth weight 1.26 kg; weaning-to-return estrus interval 5 to 8 days. In conclusion, PG 600 was found to be useful in inducing fertile estrus in prepuberal gilts, a result which will be of interest for commercial pig farms.

Animals↗

PubMed1998

Retention of intracellular fibronectin expression in primary and metastatic thyroid carcinoma: an immunohistochemical study.

We previously showed that thyroid carcinoma distinctively expresses intracellular fibronectin (FN) compared to other carcinomas. To determine the persistency of such FN accumulation in metastasis, we immunohistochemically examined the accumulation of intracellular FN in 92 cases of different carcinomas originating from the thyroid gland, lung and kidney, 44 of which showed metastasis to other organs. In all of the cases, normal epithelial cells adjacent to carcinomas did not show intracellular FN. Almost all of the cases (31/32) of thyroid carcinoma with/without metastasis to the lung and/or kidney showed intracellular FN in both the primary and metastatic lesions. Few cases (2/38) of lung carcinoma and none of the 22 cases of kidney carcinoma showed intracellular FN in the primary and metastatic lesions. In conclusion, the intracellular accumulation of FN acquired after carcinogenic transformation is not a common phenomenon in carcinomas, but rather is distinctive for thyroid carcinoma, even when it metastasizes to other organs. The immunohistochemical detection of intracellular FN may be useful for diagnosing thyroid carcinoma, even in metastatic lesions.

Adult↗

PubMed1998

GalR-mediated repression and activation of hybrid lacUV5 promoter: differential contacts with RNA polymerase.

The GalR repressor regulates expression of genes of the gal regulon in Escherichia coli. We studied the regulatory effect of GalR in vitro on a heterologous promoter, lacUV5, by placing the GalR-binding site, OE, at different locations upstream of this promoter. Despite the fact that the lacUV5 promoter is transcribed efficiently by RNA polymerase (RNP) alone, GalR modulated transcription from many of the PlacUV5 variants. Depending on the location of OE and the neighboring DNA sequence, GalR repressed, activated or had no effect on the promoter. Both repression and activation involved formation of GalR-RNP-DNA ternary complexes and required an intact c-domain of the alpha subunit of the holoenzyme. These results support the differential contact model of a regulator action, in which a regulator differentially binds to, and lowers the energy of, intermediates of transcription initiation either to hinder or to facilitate a step of initiation. The nature of the contacts depends upon the context, i.e. the geometry of the ternary complex. The observed repression and activation effect of GalR on a heterologous promoter also underscores the point that a regulator is not a dedicated protein for repression or for activation.

Binding Sites↗

PubMed1998

CRP.cAMP-dependent transcription activation of the Escherichia coli pts Po promoter by the heat shock RNA polymerase (Esigma32) in vitro.

The P0 promoter of the Escherichia coli pts operon that is activated during growth in the presence of glucose contains a recognition sequence for the RNA polymerase holoenzyme containing sigma 70 (Esigma70) which is the RNA polymerase holoenzyme responsible for the transcription of heat shock genes, and a putative recognition element for Esigma32, the Esigma32 was found to be able to transcribe from the pts P0 promoter with in vitro transcription assays using purified RNA polymerase holoenzymes. Esigma32 and Esigma70 used the same transcriptional start site and both RNA polymerases were activated in the presence of a cAMP receptor protein (CRP) and cAMP complex (CRP.cAMP). These results suggest the possibility that the contact between CRP.cAMP and the alpha subunit of the RNA polymerase can be made regardless of the kind of sigma subunit that is associated with the core RNA polymerase.

Base Sequence↗

PubMed1998

In vitro radiosensitization of human cervical carcinoma cells by combined use of 13-cis-retinoic acid and interferon-alpha2a.

BACKGROUND: Significant antitumor activity has been reported with the combined use of 13-cis-retinoic acid (cRA) and interferon-alpha2a (IFN-alpha) in the treatment of advanced-stage cervical cancers and skin cancers. Since IFN-alpha has been shown to be a modest radiation enhancer for selected malignant tumor cells and the cytotoxic activity is more enhanced by combining cRA and IFN-alpha, we hypothesized that the exposure of selected human carcinoma cells to combined cRA and IFN-alpha would render the cells highly radiosensitive. METHODS AND MATERIALS: Two human cervical carcinoma cell lines, ME-180 and HeLa-S3, were chosen for the present study because of the different characteristics of the retinoic acid receptor status of the cell lines. To demonstrate the effects of combined cRA and IFN-alpha treatment on radiation response, we exposed the cells to cRA, IFN-alpha, or a combination of the drugs for 72 h before radiation. Experiments were carried out at minimally cytotoxic concentrations of the drug for radiation studies. End points of the study were cell growth inhibition and clonogenic ability of the single-plated cells. Effects of cRA and IFN-alpha on radiation response were quantitatively analyzed by constructing the radiation cell survival curves of ME-180 and HeLa cells. RESULTS: ME-180 cells exhibited varying degrees of cytotoxicity with cRA and IFN-alpha, while HeLa cells showed no toxic effects with the same treatment. Combined treatment of cRA and IFN-alpha produced an additive cytotoxic effect in ME-180 cells. Radiosensitization was minimal when ME-180 cells were treated with either cRA or IFN-alpha before radiation. When ME-180 cells were exposed to 10 microM cRA for 48 h and 1000 U/ml IFN-alpha for 24 h prior to radiation, there was a significant enhancement in radiation-induced cell killing; the dose modification factor was 2.1 +/- 0.9 at the 1% cell-survival level. On the other hand, HeLa-S3 cells exhibited no increased cytotoxicity or radiation enhancement under the same experimental conditions. CONCLUSION: The present data provide a radiobiological basis for using cRA and IFN-alpha as a combination radiosensitizer in selected human carcinoma cells.

Antineoplastic Agents↗