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1.
Korean Journal of Otolaryngology - Head and Neck Surgery ; : 176-181, 2019.
Artículo en Coreano | WPRIM | ID: wpr-830054

RESUMEN

BACKGROUND AND OBJECTIVES@#To find more accurate way to determine the location of parotid tumors that cross anatomical criteria for the facial nerve (FN).SUBJECTS AND METHOD: Two hundred patients were included in the study and retrospectively studied. Five anatomical criteria were used to predict the location of parotid tumors on computed tomography (CT). Deep portion of tumors was measured and then, cut-off value was obtained after receiver operator curve analysis. The location of tumor was predicted by using the cut-off value and by the conventional way, in which the side where most of the tumor is located is determined as the tumor site.@*RESULTS@#The parotid tumors were located in superficial lobes in 148 cases, and in deep lobes in 52 cases by operative record. The tumors that cross the anatomical criteria were defined as ‘crossing tumor.’ The cut-off values for prediction of ‘crossing tumor’ location on CT were 6.7 mm for anatomical line, 6.4 mm for FN line, 11.2 mm for retromandibular vein, 4.9 mm for Utrecht line and 3.8 mm for Conn's arc. The accuracy of 5 anatomical criteria for ‘crossing tumor’ was between 55.9% and 81.6% when the cut-off value was used, whereas the accuracy was between 25.7% and 68.9% when conventional way was used.@*CONCLUSION@#In cases of ‘crossing tumor,’ the cut-off value obtained by measurement of deep portion of tumor can be applied to improve the diagnostic performance for the prediction of tumor location.

3.
Korean Journal of Otolaryngology - Head and Neck Surgery ; : 176-181, 2019.
Artículo en Coreano | WPRIM | ID: wpr-760104

RESUMEN

BACKGROUND AND OBJECTIVES: To find more accurate way to determine the location of parotid tumors that cross anatomical criteria for the facial nerve (FN). SUBJECTS AND METHOD: Two hundred patients were included in the study and retrospectively studied. Five anatomical criteria were used to predict the location of parotid tumors on computed tomography (CT). Deep portion of tumors was measured and then, cut-off value was obtained after receiver operator curve analysis. The location of tumor was predicted by using the cut-off value and by the conventional way, in which the side where most of the tumor is located is determined as the tumor site. RESULTS: The parotid tumors were located in superficial lobes in 148 cases, and in deep lobes in 52 cases by operative record. The tumors that cross the anatomical criteria were defined as ‘crossing tumor.’ The cut-off values for prediction of ‘crossing tumor’ location on CT were 6.7 mm for anatomical line, 6.4 mm for FN line, 11.2 mm for retromandibular vein, 4.9 mm for Utrecht line and 3.8 mm for Conn's arc. The accuracy of 5 anatomical criteria for ‘crossing tumor’ was between 55.9% and 81.6% when the cut-off value was used, whereas the accuracy was between 25.7% and 68.9% when conventional way was used. CONCLUSION: In cases of ‘crossing tumor,’ the cut-off value obtained by measurement of deep portion of tumor can be applied to improve the diagnostic performance for the prediction of tumor location.


Asunto(s)
Humanos , Nervio Facial , Métodos , Glándula Parótida , Neoplasias de la Parótida , Estudios Retrospectivos , Venas
4.
Chonnam Medical Journal ; : 178-186, 2017.
Artículo en Inglés | WPRIM | ID: wpr-788391

RESUMEN

Recepteur d'origine nantais (RON) is a receptor tyrosine kinase belonging to the subfamily of which c-MET is the prototype. Large epidemiologic studies have confirmed the strong association between RON and gastric cancer development. Constitutive activation of RON signaling directly correlates with tumorigenic phenotypes of gastric cancer and a poor survival rate in advanced gastric cancer patients. In this review, we focus on recent evidence of the aberrant expression and activation of RON in gastric cancer tumors and provide insights into the mechanism of RON signaling associated with gastric cancer progression and metastasis. Current therapeutics against RON in gastric cancer are summarized.


Asunto(s)
Humanos , Estudios Epidemiológicos , Metástasis de la Neoplasia , Fenotipo , Proteínas Tirosina Quinasas , Proteínas Proto-Oncogénicas c-met , Neoplasias Gástricas , Tasa de Supervivencia
5.
Chonnam Medical Journal ; : 178-186, 2017.
Artículo en Inglés | WPRIM | ID: wpr-89703

RESUMEN

Recepteur d'origine nantais (RON) is a receptor tyrosine kinase belonging to the subfamily of which c-MET is the prototype. Large epidemiologic studies have confirmed the strong association between RON and gastric cancer development. Constitutive activation of RON signaling directly correlates with tumorigenic phenotypes of gastric cancer and a poor survival rate in advanced gastric cancer patients. In this review, we focus on recent evidence of the aberrant expression and activation of RON in gastric cancer tumors and provide insights into the mechanism of RON signaling associated with gastric cancer progression and metastasis. Current therapeutics against RON in gastric cancer are summarized.


Asunto(s)
Humanos , Estudios Epidemiológicos , Metástasis de la Neoplasia , Fenotipo , Proteínas Tirosina Quinasas , Proteínas Proto-Oncogénicas c-met , Neoplasias Gástricas , Tasa de Supervivencia
6.
Korean Journal of Otolaryngology - Head and Neck Surgery ; : 565-569, 2017.
Artículo en Coreano | WPRIM | ID: wpr-651325

RESUMEN

BACKGROUND AND OBJECTIVES: The biological activity in antibacterial and antioxidative action of essential oils (EOs) have been investigated. In this study, we tried to evaluate the effects of Chamaecyparis obtusa EOs on producing chemical mediators by peripheral blood mononuclear cells (PBMCs). SUBJECTS AND METHOD: PBMCs from healthy volunteers were stimulated with lipopolysaccharide (LPS) and phytohaemagglutinin (PHA) in the presence of varying concentrations of EOs. Cytotoxic effects of EOs were measured using an aqueous cell proliferation assay kit and supernatants were analyzed using enzyme-linked immunosorbent assay. Tumor necrosis factor-α (TNF-α), interleukin-5, and interferon-γ (INF-γ) protein levels were measured to determine the anti-inflammatory effects of essential oil. RESULTS: EOs were found to have cytotoxic effects on PBMCs at levels of over 1%. EOs not only could induce PBMCs to produce chemical mediators, but it also significantly inhibited the LPS induced TNF-α and INF-γ productions as well as the PHA induced INF-γ production. CONCLUSION: EOs had cytotoxic effects at high concentrations and modulated chemical mediator productions from PBMC. These data suggest that EOs could be used to treat immunologic or inflammatory diseases.


Asunto(s)
Proliferación Celular , Chamaecyparis , Ensayo de Inmunoadsorción Enzimática , Voluntarios Sanos , Interleucina-5 , Métodos , Necrosis , Aceites Volátiles
7.
The Korean Journal of Internal Medicine ; : 40-45, 2016.
Artículo en Inglés | WPRIM | ID: wpr-149376

RESUMEN

BACKGROUND/AIMS: To evaluate a new monoclonal antibody for Helicobacter pylori urease in gastric tissue. METHODS: A total of 107 volunteers were enrolled. All subjects underwent a 13C-urea breath test and esophagogastroduodenoscopy. Gastric aspirates were analyzed for pH and ammonia. Six biopsy specimens in the gastric antrum and body were obtained for a rapid urease test and histology. The new monoclonal antibody-based H. pylori urease test (HPU) was performed to rapidly and qualitatively detect urease in two biopsy specimens. RESULTS: H. pylori infection was diagnosed in 73 subjects. The sensitivity and specificity of the HPU was 89% and 74%, respectively. The subjects were divided into two groups: one with true-positive and true-negative HPU results (n = 90) and the other with false-positive and false-negative HPU results (n = 17). Across all subjects, ammonia levels were 900.5 +/- 646.7 and 604.3 +/- 594.3 mumol/L (p > 0.05), and pH was 3.37 +/- 1.64 and 2.82 +/- 1.51 (p > 0.05). Sensitivity was higher in the presence of atrophic gastritis or intestinal metaplasia. CONCLUSIONS: HPU detected H. pylori in approximately 10 min. Gastric aspirate ammonia and pH levels did not affect the test results. Sensitivity was good in the presence of atrophic gastritis or intestinal metaplasia.


Asunto(s)
Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Anticuerpos Monoclonales/inmunología , Proteínas Bacterianas/análisis , Biomarcadores/análisis , Biopsia , Reacciones Falso Negativas , Reacciones Falso Positivas , Gastritis Atrófica/diagnóstico , Infecciones por Helicobacter/diagnóstico , Helicobacter pylori/enzimología , Pruebas Inmunológicas , Metaplasia , Valor Predictivo de las Pruebas , Antro Pilórico/microbiología , Reproducibilidad de los Resultados , Factores de Tiempo , Ureasa/análisis , Flujo de Trabajo
8.
Korean Journal of Otolaryngology - Head and Neck Surgery ; : 770-774, 2016.
Artículo en Coreano | WPRIM | ID: wpr-653250

RESUMEN

BACKGROUND AND OBJECTIVES: Snoring is a condition that affects a large percentage of population and is associated with various medical and social complications. However, there are only few published reports investigating the effects of chronic snoring exposure on hearing. In the present study, we examined whether there is an association between chronic snoring noise exposure and noise induced hearing impairment not only in snorers but also in their spouses. Subjects and MethodZZSixty snorers and 27 spouses under the age of 55 were recruited. All participants had more than 5 years of exposure to snoring. Questionnaire for snoring and pure tone audiometry were conducted. Subjects were classified into normal hearing group and hearing impairment group. SUBJECTS AND METHOD: Sixty snorers and 27 spouses under the age of 55 were recruited. All participants had more than 5 years of exposure to snoring. Questionnaire for snoring and pure tone audiometry were conducted. Subjects were classified into normal hearing group and hearing impairment group. RESULTS: Forty percent of snorers and 25.9% of spouses had hearing impairment. The snorers with hearing impairment had longer duration of snoring than the snorers with normal hearing. However, there were no statistical differences in loudness of snoring between the two groups. In the spouse group, there were statistical differences in loudness of exposed snoring and in duration of snoring exposure between the hearing impairment group and the normal hearing group. CONCLUSION: The result of this study indicated that chronic exposure to snoring noise may be associated with hearing impairment in snorers and their spouses. But in the snorers, further studies are required to identify the factors other than snoring noise associated with hearing impairment.


Asunto(s)
Humanos , Audiometría , Pérdida Auditiva , Audición , Métodos , Ruido , Ronquido , Esposos
9.
Chonnam Medical Journal ; : 6-14, 2014.
Artículo en Inglés | WPRIM | ID: wpr-788283

RESUMEN

This study was designed to evaluate the efficacy of an orally administered aqueous extract of glutinous rice (GRE) to protect against acute gastric mucosal lesions induced by ethanol, indomethacin, and water immersion restraint stress in rats and to characterize the active substances responsible for the protection. GRE was shown to dose-dependently prevent the gastric lesions induced by the above ulcerogenic treatments at doses of 30 to 300 mg/kg. GRE treatment increased the gastric mucin content and partially blocked the ethanol-induced depletion of the gastric mucus layer. Also, it increased the nonprotein sulfhydryl concentration in the gastric mucosa. The gastroprotective action of GRE was markedly enhanced by co-treatment with 4-8 mg/kg tea extracts. The activity of GRE was completely lost by heat treatment at 80degrees C for 3 min or treatment with 0.01% pepsin at 37degrees C for 1 h. Protein extraction studies indicated that prolamins are involved in the gastroprotective activity of GRE. Our results suggest that glutinous rice proteins are useful for the prevention and treatment of gastritis and peptic ulcer.


Asunto(s)
Animales , Ratas , Etanol , Mucinas Gástricas , Mucosa Gástrica , Gastritis , Calor , Inmersión , Indometacina , Moco , Pepsina A , Úlcera Péptica , Prolaminas , , Úlcera , Agua
10.
Chonnam Medical Journal ; : 6-14, 2014.
Artículo en Inglés | WPRIM | ID: wpr-111166

RESUMEN

This study was designed to evaluate the efficacy of an orally administered aqueous extract of glutinous rice (GRE) to protect against acute gastric mucosal lesions induced by ethanol, indomethacin, and water immersion restraint stress in rats and to characterize the active substances responsible for the protection. GRE was shown to dose-dependently prevent the gastric lesions induced by the above ulcerogenic treatments at doses of 30 to 300 mg/kg. GRE treatment increased the gastric mucin content and partially blocked the ethanol-induced depletion of the gastric mucus layer. Also, it increased the nonprotein sulfhydryl concentration in the gastric mucosa. The gastroprotective action of GRE was markedly enhanced by co-treatment with 4-8 mg/kg tea extracts. The activity of GRE was completely lost by heat treatment at 80degrees C for 3 min or treatment with 0.01% pepsin at 37degrees C for 1 h. Protein extraction studies indicated that prolamins are involved in the gastroprotective activity of GRE. Our results suggest that glutinous rice proteins are useful for the prevention and treatment of gastritis and peptic ulcer.


Asunto(s)
Animales , Ratas , Etanol , Mucinas Gástricas , Mucosa Gástrica , Gastritis , Calor , Inmersión , Indometacina , Moco , Pepsina A , Úlcera Péptica , Prolaminas , , Úlcera , Agua
11.
Gut and Liver ; : 30-34, 2013.
Artículo en Inglés | WPRIM | ID: wpr-214014

RESUMEN

BACKGROUND/AIMS: The objective of this study was to evaluate a monoclonal antibody-based test to detect Helicobacter pylori-specific antigen in gastric aspirates from humans. METHODS: Sixty-one volunteers were enrolled in the study. All of the subjects underwent a 13C-urea breath test (UBT) before esophagogastroduodenoscopy. Gastric aspirates were analyzed for pH and ammonia and used for polymerase chain reaction (PCR), culture, and monoclonal antibody-based detection of H. pylori. Multiple biopsies of the gastric antrum and body were obtained for a rapid urease test (RUT) and histological evaluation. RESULTS: Thirty-six subjects were H. pylori-positive and 25 were H. pylori-negative according to the UBT results. Compared with the H. pylori-negative subjects, H. pylori-positive subjects had a higher pH (4.77+/-1.77 vs 3.49+/-1.30, p<0.05) and ammonia level (1,130.9+/-767.4 vs 184.2+/-126.3, p<0.0001). The sensitivities and specificities of the PCR test, RUT, culture test, and monoclonal antibody-based test were 100% and 72%, 89% and 100%, 47% and 100%, and 78% and 100%, respectively. CONCLUSIONS: The monoclonal antibody-based test for diagnosing H. pylori infection in gastric aspirates has increased sensitivity compared with the culture test and specificity as high as that of the RUT. The test may be useful as an additive test for examining gastric aspirates.


Asunto(s)
Amoníaco , Biopsia , Pruebas Respiratorias , Endoscopía del Sistema Digestivo , Helicobacter , Helicobacter pylori , Concentración de Iones de Hidrógeno , Reacción en Cadena de la Polimerasa , Antro Pilórico , Sensibilidad y Especificidad , Ureasa
12.
The Korean Journal of Gastroenterology ; : 27-32, 2010.
Artículo en Coreano | WPRIM | ID: wpr-158683

RESUMEN

BACKGROUND/AIMS: Helicobacter pylori (H. pylori) transmission route is not yet clearly understood. Isolating H. pylori from stool, saliva, and vomitus is very difficult. However, H. pylori could be cultured from feces in the setting of rapid gastrointestinal tract transit. The aim of this study was to isolate H. pylori by culture and PCR in the rectum and terminal ileum during colonoscopy. METHODS: Twenty subjects with positive UBT (urea breath test) were included. We performed polymerase chain reaction (PCR) test and culture of H. pylori with the rectal fluid and terminal ileal fluid during colonoscopy. RESULTS: H. pylori was cultured with rectal fluid from 9 (45.0%) of 20 subjects and with ileal fluid from 11 (55.0%) of 20 subjects. H. pylori was a little more frequently cultured from the terminal ileal fluid than the rectal fluid without statistical significance (p>0.05). PCR test detected flaA (16/20, 80.0% and 17/20, 85.0%), 16S rRNA gene (16/20, 80.0% and 17/20, 85.0%), cagA (10/20, 50.0% and 12/20, 60.0%), and ureC (9/20, 45% and 11/20, 54.5%) from the rectal fluid and the terminal ileal fluid, respectively. The specificity and sensitivity of ureC were 100%. CONCLUSIONS: H. pylori could be cultured from the rectal fluid and terminal ileal fluid in the setting of rapid gastrointestinal tract transit. These results suggest of fecal-oral transmission of H. pylori.


Asunto(s)
Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Antígenos Bacterianos/genética , Proteínas Bacterianas/genética , Pruebas Respiratorias , Electrólitos/administración & dosificación , Heces/microbiología , Infecciones por Helicobacter/diagnóstico , Helicobacter pylori/genética , Íleon/microbiología , Polietilenglicoles/administración & dosificación , Reacción en Cadena de la Polimerasa , ARN Ribosómico 16S/genética , Recto/microbiología , Sensibilidad y Especificidad , Urea/análisis , Ureasa/genética
13.
The Korean Journal of Gastroenterology ; : 164-169, 2007.
Artículo en Coreano | WPRIM | ID: wpr-147156

RESUMEN

BACKGROUND/AIMS: Telomeres are simple repeat elements located at each chromosome end of eukaryotic cells. The main function of telomeres is to cap the chromosome end and protect it from enzymatic attack. Telomerase that facilitates the synthesis of telomere has been detected in not only cancer but also precancerous lesion. In this study, we compared the telomerase expression between low grade and high grade colorectal tubular adenoma. METHODS: Among thissues from forty eight patients with colorectal tubular adenoma (23 low grade and 25 high grade colorectal dysplasia), telomerase expressions were evaluated by immunohistochemical staining. RESULTS: We classified 48 patients into two groups by the extent of nuclei staining pattern. High telomerase expression was a group which showed staining nucleus pattern above 50% in tubular adenoma. Low telomerase expression was a group which showed staining pattern nucleus below 50%. Twelve in 25 high grade colorectal dysplasia showed high telomerase expression (48%). Only one in 23 low grade colorectal dysplasia showed high telomerase expression (4%). Telomerase expression was much higher in the tissues from the patients with high grade than in those with low grade colorectal dysplasia (p<0.05). CONCLUSIONS: Activation of telomerase may be related to the malignant potential in colorectal epithelial cells. Further studies are needed to define the role of telomerase in colorectal tumorigenesis.


Asunto(s)
Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adenocarcinoma/enzimología , Neoplasias Colorrectales/enzimología , Inmunohistoquímica , Estadificación de Neoplasias , Estudios Retrospectivos , Telomerasa/inmunología
14.
Korean Journal of Medicine ; : 293-301, 2006.
Artículo en Coreano | WPRIM | ID: wpr-189991

RESUMEN

BACKGROUND: Human YB-1 is a transcription factor that binds to the inverted CCAAT box in the promoter region of a variety of genes such as PCNA, DNA polymerase and MDR. In this study we evaluated the effect of YB-1 antisense oligonucleotides on tumor cell growth. METHODS: Chang liver, HepG2 and CT-26 cells were cultured as immortalized cell lines. The MTT (3-[4,5-dimethylthiazol-2-yl] 2,5-diphenyltetrazolium bromide) assay, Northern blot and flow cytometric analyses were used to determine cell growth, gene expression and cell cycle changes. In an animal model, CT-26 cells were injected into Balb/c mice to induce tumor; YB-1 antisense oligonucleotides were injected into the tail vein or tumor tissue of the mice; change of tumor size was then measured. RESULTS: Phosphorothioated YB-1 antisense oligonucleotides suppressed the proliferation of the immortalized liver cells (Chang liver cells) and a variety of cancer cells (HepG2 and CT-26 cells); however, it did not inhibit normal cell growth. The DOTAP/antisense oligonucleotide mixture showed stronger effects on cell proliferation than did the antisense oligonucleotide alone. The YB-1 antisense oligonucleotide decreased specific expression of the YB-1 mRNA in the immortalized cancer cell lines. Flow cytometric analysis revealed that the inhibition of cell proliferation might have been due to a decrease in the S phase of the cell cycle. We found that in an animal tumor model, the administration of the YB-1 antisense oligonucleotide, in the vein or tumor tissues, decreased the tumor size significantly. CONCLUSIONS: These results suggest that the YB-1 antisense oligonucleotide may inhibit growth of a variety of cancer cells.


Asunto(s)
Animales , Humanos , Ratones , Northern Blotting , Ciclo Celular , Línea Celular , Proliferación Celular , ADN , Expresión Génica , Hígado , Modelos Animales , Oligonucleótidos Antisentido , Antígeno Nuclear de Célula en Proliferación , Regiones Promotoras Genéticas , ARN Mensajero , Fase S , Factores de Transcripción , Venas
15.
Cancer Research and Treatment ; : 444-449, 2002.
Artículo en Inglés | WPRIM | ID: wpr-27225

RESUMEN

PURPOSE: MMP-2, 72 kDa-type IV collagenase, plays a major role in the migration and growth of tumor cells, a process that requires the disintegration of basement membrane. Activation of MMP-2 is correlated with the invasiveness of various tumors. The aim of this study was to determine the sequence-specific phosphorothioated oligodeoxynucleotides (ODNs) inhibiting the translation of MMP-2 mRNA and the subsequent invasiveness of tumor cells. MATERIALS AND METHODS: Eight types of antisense ODNs were designed and each (8micro gram/ml) were transfected into HT1080 cells. The effects of these antisense ODNs on MMP expression were examined by gelatin zymography, Western blot, Northern blot and matrigel assay. RESULTS: Antisense-5 (+904~923), antisense-6 (+1274~+1293) and antisense-7 (+1646~+1665) reduced the MMP-2 activity of the culture supernatant in HT1080 fibrosarcoma cells. Treatment with antisense-6 showed inhibition of MMP-2 mRNA and protein, and in vitro invasion in a dose-dependent manner. CONCLUSION: Antisense-6 might be one of the therapeutic candidates for tumor invasion and metastasis.


Asunto(s)
Humanos , Membrana Basal , Northern Blotting , Western Blotting , Colagenasas , Fibrosarcoma , Gelatina , Metaloproteinasa 2 de la Matriz , Metástasis de la Neoplasia , Oligodesoxirribonucleótidos , ARN Mensajero
16.
Cancer Research and Treatment ; : 426-431, 2002.
Artículo en Coreano | WPRIM | ID: wpr-199470

RESUMEN

PURPOSE: The role of P38 mitogen-activated protein kinase (MAPK) in gastric cancer invasion has not yet been determined. In this study, we examined the effects of SB203580, a specific P38 MAPK inhibitor, on the in vitro invasion of gastric cancer and upon the molecules involved in this process. MATERIALS AND METHODS: Human gastric cancer SNU-638 cells were maintained in RPMI 1640 supplemented with 10% FBS. BIOCOAT matrigel invasion chambers were used to examine in vitro invasiveness, zymography for gelatinase activity, CAT assay for uPA promoter activity and Western and Northern blotting to determine protein and mRNA levels, respectively. RESULTS: Treatment of SNU-638 cells with SB203580, a specific P38 MAPK inhibitor, reduced in vitro invasiveness, dose-dependently. SB203580 treatment was found to decrease both mRNA expression and uPA promoter activity in gastric SNU-638 cells. In vitro invasion of SNU-638 cells was partially abrogated by uPA-neutralizing antibodies. The activities of MMPs were not significantly altered by SB203580. CONCLUSION: Our results suggest that P38 MAPK is a potential therapeutic target for inhibiting uPA-dependent gastric tumor invasiveness and metastasis.


Asunto(s)
Animales , Gatos , Humanos , Anticuerpos , Northern Blotting , Gelatinasas , Metaloproteinasas de la Matriz , Metástasis de la Neoplasia , Proteínas Quinasas p38 Activadas por Mitógenos , Proteínas Quinasas , ARN Mensajero , Neoplasias Gástricas
17.
Experimental & Molecular Medicine ; : 221-226, 1998.
Artículo en Inglés | WPRIM | ID: wpr-159766

RESUMEN

Reactive oxygen species such as superoxides, hydrogen peroxide (H2O2) and hydroxyl radicals have been suggested to be involved in the catalytic action of nitric oxide synthase (NOS) to produce NO from L-arginine. An examination was conducted on the effects of oxygen radical scavengers and oxygen radical-generating systems on the activity of neuronal NOS and guanylate cyclase (GC) in rat brains and NOS from the activated murine macrophage cell line J774. Catalase and superoxide dismutase (SOD) showed no significant effects on NOS or GC activity. Nitroblue tetrazolium (NBT, known as a superoxide radical scavenger) and peroxidase (POD) inhibited NOS, but their inhibitory actions were removed by increasing the concentration of arginine or NADPH respectively, in the reaction mixture. NOS and NO-dependent GC were inactivated by ascorbate/FeSO4 (a metal-catalyzed oxidation system), 2'2'-azobis-amidinopropane (a peroxy radical producer), and xanthine/xanthine oxidase (a superoxide generating system). The effects of oxygen radicals or antioxidants on the two isoforms of NOS were almost similar. However, H2O2 activated GC in a dose-dependent manner from 100 microM to 1 mM without significant effects on NOS. H2O2-induced GC activation was blocked by catalase. These results suggested that oxygen radicals inhibited NOS and GC, but H2O2 could activate GC directly.


Asunto(s)
Ratas , Animales , Antioxidantes/farmacología , Encéfalo/enzimología , Catalasa/farmacología , Línea Celular , Guanilato Ciclasa/metabolismo , Peróxido de Hidrógeno/farmacología , Macrófagos/enzimología , NADP/farmacología , Óxido Nítrico Sintasa/metabolismo , Nitroazul de Tetrazolio/farmacología , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal , Superóxido Dismutasa/farmacología
18.
Experimental & Molecular Medicine ; : 171-175, 1997.
Artículo en Inglés | WPRIM | ID: wpr-58968

RESUMEN

Hemin blocked lipid peroxidations induced by either ascorbate/FeSO4, a metal-catalyzed oxidation system, or 2,2'-azobis-2-amidino-propane hydrochloride (ABAP) which produces peroxy radicals at constant rates. Hemin at very low micromolar concentrations strongly inhibited the ascorbate/FeSO4-induced peroxidation of rat liver phopholipids, soybean phosphatidylcholine and arachidonic acid, and this inhibition was also evident with the use of ABAP, although much higher concentrations of hemin were required than those for the inhibition of ascorbate/FeSO4-induced lipid peroxidation. However, hemoproteins such as hemoglobin, myoglobin and cytochrome C did not show any significant effect on this lipid peroxidation. Hemopexin and albumin abolished the inhibitory action of hemin. During incubation with ascorbate/FeSO4 or ABAP, hemin underwent a change in its absorption spectrum, resulting in a progressive decrease in the peak height of the characteristic absorption band at 385 nm. The above results suggest that hemin may act as an important antioxidant in vivo, protecting lipids from the peroxidative damage.


Asunto(s)
Animales , Ratas , Absorción , Ácido Araquidónico , Citocromos c , Hemina , Hemopexina , Peroxidación de Lípido , Hígado , Mioglobina , Fosfatidilcolinas , Glycine max
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