RESUMEN
BACKGROUND: The efficacy and safety of transanal lateral pelvic lymph node dissection (TaLPLND) in rectal cancer has not yet been clarified. The aim of the present study was to evaluate the short-term results as an initial experience of TaLPLND. METHODS: This retrospective study included patients with middle to lower rectal cancer who underwent TaLPLND from July 2018 to July 2021. Our institutions targeted lymph nodes in the internal iliac area and the obturator area for lateral pelvic lymph node dissection (LPLND). RESULTS: A total of 30 consecutive patients with rectal cancer were included in this analysis. The median age was 60 years (range, 36-83 years), and the male-female ratio was 2:1. The median operative time was 362 min (IQR, 283-661 min), and the median intraoperative blood loss was 74 ml (IQR, 5-500 ml). Intraoperative blood transfusion was required in one case. No cases required conversion to laparotomy. TaLPLND was performed bilaterally in 13 patients (43.3%). Five patients (16.7%) underwent LPLND with combined resection of the internal iliac vessels. The median distance of the distal margin from the anal verge was 20 mm. The pathological radial margin (pRM) was positive in one case, and the negative pRM rate was 96.7%. Short-term postoperative complications (Clavien-Dindo classification grade ≥ II) were observed in nine cases (30.0%). There were no cases of reoperation or mortality. The median number of harvested lateral pelvic lymph nodes was 11 (range, 3-28). On pathological examination, lateral pelvic lymph nodes were positive for metastasis in seven cases (23.3%). CONCLUSIONS: TaLPLND appeared to be beneficial from an oncological point of view because it was close to the upstream lymphatic drainage from the tumor. The short-term outcomes of this initial experience indicate that this novel approach is feasible.
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Laparoscopía , Neoplasias del Recto , Humanos , Masculino , Femenino , Persona de Mediana Edad , Estudios Retrospectivos , Laparoscopía/métodos , Escisión del Ganglio Linfático/métodos , Ganglios Linfáticos/cirugía , Ganglios Linfáticos/patología , Neoplasias del Recto/cirugía , Neoplasias del Recto/patologíaRESUMEN
BACKGROUND: We previously reported that indocyanine green fluorescence imaging (ICG-FI)-guided laparoscopic lateral pelvic lymph node dissection (LPLND) was able to increase the total number of harvested lateral pelvic lymph nodes without impairing functional preservation. However, the long-term outcomes of ICG-FI-guided laparoscopic LPLND have not been evaluated. The aim of the present study was to compare the long-term outcomes of ICG-FI-guided laparoscopic LPLND to conventional laparoscopic LPLND without ICG-FI. METHODS: This was a retrospective, multi-institutional study with propensity score matching. The study population included consecutive patients with middle-low rectal cancer (clinical stage II to III) who underwent laparoscopic LPLND between January 2013 and February 2018. The main evaluation items in this study were the 3-year overall survival, relapse-free survival (RFS), local recurrence rate, and lateral local recurrence (LLR) rate. RESULTS: A total of 172 patients with middle-lower rectal cancer who had undergone laparoscopic LPLND were included in this study. After propensity score matching, 58 patients were matched in each of the ICG-FI and non-ICG-FI groups. There were no substantial differences in the baseline characteristics between the two groups. The ICG-FI group and non-ICG-FI group included 40 and 38 women and had a median age of 65 (IQR 60-72) and 66 (IQR 60-73) years, respectively. The median follow-up for all patients was 63.7 (IQR 51.3-76.8) months. The estimated respective 3-year overall survival, RFS, and local recurrence rates were 93.1%, 70.7%, and 5.2% in the ICG-FI group and 85.9%, 71.7%, and 12.8% in the non-ICG-FI group (p = 0.201, 0.653, 0.391). The 3-year cumulative LLR rate was 0% in the ICG-FI group and 9.3% in the non-ICG-FI group (p = 0.048). CONCLUSIONS: This study revealed that laparoscopic LPLND combined with ICG-FI was able to decrease the LLR rate. It appears that ICG-FI could contribute to improving the quality of laparoscopic LPLND and strengthening local control of the lateral pelvis. TRIALS REGISTRATION: This study was registered with the Japanese Clinical Trials Registry as UMIN000041372 ( http://www.umin.ac.jp/ctr/index.htm ).
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Laparoscopía , Neoplasias del Recto , Humanos , Femenino , Persona de Mediana Edad , Anciano , Verde de Indocianina , Estudios de Cohortes , Estudios Retrospectivos , Puntaje de Propensión , Recurrencia Local de Neoplasia/cirugía , Escisión del Ganglio Linfático/métodos , Ganglios Linfáticos/patología , Laparoscopía/métodos , Neoplasias del Recto/diagnóstico por imagen , Neoplasias del Recto/cirugía , Neoplasias del Recto/patología , Imagen Óptica/métodosRESUMEN
Streptococcal toxic shock syndrome (STSS) is a severe invasive infection characterized by the sudden onset of shock, multiorgan failure, and high mortality. Although STSS is mainly caused by Streptococcus pyogenes, group G streptococcus identified as S. dysgalactiae subsp. equisimilis (SDSE) causing STSS has also been reported; however, no study has analyzed >100 isolates of SDSE causing STSS. Therefore, we characterized the emm genotype of 173 SDSE isolates obtained from STSS patients in Japan during 2014-2016 and performed antimicrobial susceptibility testing using the broth microdilution method and emm gene typing. The predominant emm genotype was found to be stG6792, followed by stG485, stG245, stG10, stG6, and stG2078. These six genotypes constituted more than 75% of the STSS isolates. The proportion of each emm genotype in STSS isolates correlated with that in invasive isolates previously reported. We found that 16.2% of the isolates showed clindamycin resistance. The proportion of clindamycin-resistant SDSE isolates was significantly higher than that of S. pyogenes isolates. Thus, while treating STSS caused by SDSE, it is necessary to consider the possibility of clindamycin resistance and to ensure judicious use of the drug.
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Farmacorresistencia Bacteriana , Choque Séptico/microbiología , Infecciones Estreptocócicas/microbiología , Streptococcus pyogenes , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antibacterianos/uso terapéutico , Antígenos Bacterianos/genética , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas Portadoras/genética , Clindamicina/uso terapéutico , Femenino , Técnicas de Genotipaje , Humanos , Japón/epidemiología , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Choque Séptico/tratamiento farmacológico , Choque Séptico/epidemiología , Infecciones Estreptocócicas/tratamiento farmacológico , Infecciones Estreptocócicas/epidemiología , Streptococcus pyogenes/clasificación , Streptococcus pyogenes/efectos de los fármacos , Streptococcus pyogenes/genética , Streptococcus pyogenes/aislamiento & purificaciónRESUMEN
Streptococcal toxic shock syndrome (STSS) is a severe invasive infection characterized by the sudden onset of shock, multi-organ failure, and high mortality. In Japan, appropriate notification measures based on the Infectious Disease Control law are mandatory for cases of STSS caused by ß-haemolytic streptococcus. STSS is mainly caused by group A streptococcus (GAS). Although an average of 60-70 cases of GAS-induced STSS are reported annually, 143 cases were recorded in 2011. To determine the reason behind this marked increase, we characterized the emm genotype of 249 GAS isolates from STSS patients in Japan from 2010 to 2012 and performed antimicrobial susceptibility testing. The predominant genotype was found to be emm1, followed by emm89, emm12, emm28, emm3, and emm90. These six genotypes constituted more than 90% of the STSS isolates. The number of emm1, emm89, emm12, and emm28 isolates increased concomitantly with the increase in the total number of STSS cases. In particular, the number of mefA-positive emm1 isolates has escalated since 2011. Thus, the increase in the incidence of STSS can be attributed to an increase in the number of cases associated with specific genotypes.
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Choque Séptico/epidemiología , Infecciones Estreptocócicas/epidemiología , Streptococcus pyogenes , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Clindamicina/farmacología , Farmacorresistencia Bacteriana/genética , Eritromicina/farmacología , Femenino , Genotipo , Humanos , Lactante , Japón/epidemiología , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Prevalencia , Choque Séptico/microbiología , Infecciones Estreptocócicas/microbiología , Streptococcus pyogenes/efectos de los fármacos , Streptococcus pyogenes/genética , Streptococcus pyogenes/aislamiento & purificación , Adulto JovenRESUMEN
We surveyed emm genotypes of group A streptococcus (GAS) isolates from patients with severe invasive streptococcal infections during 2001-2005 and compared their prevalence with that of the preceding 5 years. Genotype emm1 remained dominant throughout 2001 to 2005, but the frequency rate of this type decreased compared with the earlier period. Various other emm types have appeared in recent years indicating alterations in the prevalent strains causing severe invasive streptococcal infections. The cover of the new 26-valent GAS vaccine fell from 93.5% for genotypes of isolates from 1996-2000 to 81.8% in 2001-2005.
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Antígenos Bacterianos/genética , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas Portadoras/genética , Infecciones Estreptocócicas/genética , Streptococcus pyogenes/genética , Femenino , Genotipo , Humanos , Japón/epidemiología , Masculino , Prevalencia , Infecciones Estreptocócicas/epidemiología , Infecciones Estreptocócicas/microbiología , Streptococcus pyogenes/aislamiento & purificaciónRESUMEN
BACKGROUND: Sulfhydryl (SH) compounds are essential in maintaining mucosal integrity in the gastrointestinal tract. A decrease in colonic mucosal SH compounds affects the redox status of the mucosa, resulting in vulnerability to further attacks. Therefore, there is a strong need for in vivo evaluation of SH compounds in the colonic mucosa. AIMS: The aim of the current study was to establish a method of evaluating levels of SH compounds in the colonic mucosa of live animals before and after induction of colitis. METHODS: Murine experimental colitis was induced by instillation of trinitrobenzene sulphonic acid (TNBS) dissolved in 50% ethanol into the colon via the anus. For evaluation of mucosal SH compounds in the colon, 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (carbamoyl-PROXYL), a stable nitroxide radical, was instilled into the colonic lumen of live mice and the spin clearance rate was measured by L-band electron spin resonance (ESR) spectroscopy. RESULTS: Morphological study showed that mucosal damage was severe one or two days after TNBS instillation. The colonic mucosa started to regenerate at four days, and looked normal at seven days, after induction of colitis. The spin clearance rate of carbamoyl-PROXYL decreased significantly at 0.5, 1, 2, and 4 days after induction of colitis compared with mice before TNBS instillation. Surprisingly, although the colonic mucosa looked normal seven days after TNBS administration, the spin clearance rate still remained significantly slow. The spin clearance rate returned to normal 14 days after induction of colitis. The change in in vivo spin clearance rate was consistent with the time dependent change in mucosal reduced glutathione, a major component of SH compounds. CONCLUSION: The spin clearance rate obtained by L-band ESR spectroscopy in combination with carbamoyl-PROXYL can give an estimate of the level of colonic mucosal SH compounds in live animals and is useful for evaluating the mucosal defence system against oxidative stress.
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Colitis/metabolismo , Espectroscopía de Resonancia por Spin del Electrón/métodos , Compuestos de Sulfhidrilo/análisis , Animales , Colitis/inducido químicamente , Espectroscopía de Resonancia por Spin del Electrón/instrumentación , Ratones , Ratones Endogámicos C57BL , Ácido TrinitrobencenosulfónicoRESUMEN
An imaging technique of electrically detected magnetic resonance (EDMR) was newly developed. Because the EDMR signal is obtained from paramagnetic recombination centers, one may expect the image to represent the distribution of defect and/or impurity sites in the sample. We successfully obtained EDMR images of a light-illuminated silicon plate 8 mm in width and 15 mm in length, which was cut from a silicon wafer (n-type, 100 Omega cm), under ESR irradiation at a frequency of 890 MHz (wavelength, 340 mm). The reproducibility of the EDMR image obtained from a sample was amply satisfactory. When the oxidized surface of the silicon was removed, the EDMR signal disappeared. Although the EDMR signal reappeared when the surface of the sample became reoxidized, the EDMR image obtained was slightly different from the earlier one. This finding shows that the EDMR image obtained from the sample shows the distribution of defects at the Si/SiO(2) interface.
RESUMEN
Oxygen consumption of individual bovine embryos was noninvasively quantified by scanning electrochemical microscopy (SECM). A probe microelectrode was used to scan near a single embryo surface in a culture medium to monitor the oxygen reduction current at 37 degrees C, under a water-saturated atmosphere of 5% CO2 and 95% air. The oxygen concentration profiles near the embryos were in good agreement with the theoretical spherical diffusion. When an embryo reached the stage of a morula with a 74-microm radius on day 6 after in vitro fertilization, the oxygen concentration difference (deltaC) between the bulk solution and the morula surface was 6.90 +/- 1.35 microM. The oxygen consumption rate (F) of the single morula was estimated to be (1.40 +/- 0.27) x 10(-14) mol s(-1). After the SECM measurement, the embryo was continuously cultured for another 2 days and grew to the stage of a blastocyst with a 100-microm radius. For the blastocyst, the deltaC values for the inner cell mass side and the trophoblast side were 16.40 +/- 1.83 and 9.14 +/- 1.68 microM, respectively. The oxygen consumption rate of the blastocyst was found to be in the range of (2.50 +/- 0.46) x 10(-14) mol s(-1) < F < (4.49 +/- 0.50) x 10(-14) mol s(-1). We have carried out SECM measurements for 19 embryos, and the results were compared in detail with these from an optical microscopic observation. The deltaC values for the morulae on day 6 after in vitro fertilization were strongly related to the morphological embryo quality. The morulae showing a larger deltaC value developed into blastocysts of a larger size, and the deltaC value after the subsequent 2 days of cultivation was found to be increased.
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Embrión de Mamíferos/metabolismo , Microscopía de Sonda de Barrido , Consumo de Oxígeno/fisiología , Oxígeno/análisis , Oxígeno/metabolismo , Animales , Bovinos , Electroquímica/instrumentaciónRESUMEN
OBJECTIVES: The purpose of this investigation was to differentiate chronic pulmonary thromboembolism (CPTE) from primary pulmonary hypertension (PPH) by means of the indexes of pulmonary arterial reflection. BACKGROUND: These differences in the primary lesions would make pulmonary artery reflection occur earlier in CPTE than in PPH. Although the analysis of pulsatility of pulmonary arterial pressure is useful in the differential diagnosis of PPH and CPTE, it is not known whether the analysis of pulmonary artery reflection can differentiate CPTE from PPH. METHODS: Since CPTE predominantly involves the proximal arteries, whereas PPH involve the peripheral arteries, we hypothesized that patients with CPTE have a large augmentation index and a short inflection time. For this study, we enrolled 62 patients who had CPTE (31 patients) and PPH (31 patients). We measured pulmonary arterial pressure using a fluid filled system that included a balloon-tipped flow directed catheter. To quantify the pulmonary artery reflection, we used the augmentation index and inflection time. RESULTS: The augmentation index was markedly higher in CPTE than it was in PPH (27.4% +/- 15.2% [SD] and -25.1% +/- 26.9%, respectively, p < 0.001) and was diagnostic in separating the two groups. Inflection time separated the two groups reasonably well (97 +/- 20 ms and 210 +/- 49 ms, respectively, p < 0.001). CONCLUSIONS: The analysis of pulmonary arterial reflection is useful in the differential diagnosis of CPTE and PPH.
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Hipertensión Pulmonar/fisiopatología , Embolia Pulmonar/fisiopatología , Adulto , Anciano , Presión Sanguínea , Enfermedad Crónica , Femenino , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Curva ROC , Sensibilidad y Especificidad , Resistencia VascularRESUMEN
A new magnetometer utilizing a longitudinally detected ESR (LODESR) method was developed. The probe head of the LODESR magnetometer is equipped with a single-turn coil (8 mm in diameter) which has a very wide bandwidth because the reactance of the coil is always smaller than the resistance of the transmission line (50 ohm) at frequencies less than 700 MHz. Thus, an absolute magnetic field could be measured over a wide range (2 to 9 mT) using this magnetometer without changing the probe head.
RESUMEN
The in vivo reducing ability of a nitroxide radical, 4-hydroxyl-2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPOL), in the liver of rats was estimated by using an electron spin resonance spectrometer equipped with a surface-coil-type resonator following administration of glucose. Both oral and intravenous administration of glucose significantly enhanced the reduction capacity. In vitro studies show that the reduction site of TEMPOL in the hepatic homogenate is located in the mitochondrial respiratory chain and microsomal electron transport system. These findings indicate that the enhancement of activity of these systems caused by the glucose administration prompts reduction of TEMPOL in the liver.
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Óxidos N-Cíclicos/farmacocinética , Glucosa/farmacología , Hígado/metabolismo , Animales , Espectroscopía de Resonancia por Spin del Electrón/métodos , Cinética , Hígado/efectos de los fármacos , Masculino , NAD/metabolismo , Oxidación-Reducción , Ratas , Ratas Wistar , Marcadores de SpinRESUMEN
EPR imaging by using an acyl-protected hydroxylamine, 1-acetoxy-3-carbamoyl-2,2,5,5-tetramethylpyrrolidine (ACP), in the head of a living rat after kainic acid (KA)-induced epileptic seizures was performed. ACP is a stable non-radical compound, but is easily deprotected with intracellular esterase to yield a hydroxylamine, which is oxidized by intracellular oxidative stress to yield an EPR-detectable nitroxide radical. From in vivo image data, the average values of EPR signal intensity from the hippocampus, striatum, and cerebral cortex were computed. There was no significant difference in cortical signal intensity between the control and KA-treated rats. The signal intensities from the hippocampus and striatum for the KA-treated rats were significantly higher than those for the control. The in vitro study showed that almost the same quantity of ACP moved into all regions of the brain of the control and KA-treated rats. These findings indicate that following a KA-induced seizure, the oxidative stress in the hippocampus and striatum is enhanced, but not so in the cerebral cortex.
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Corteza Cerebral/patología , Cuerpo Estriado/patología , Espectroscopía de Resonancia por Spin del Electrón , Hipocampo/patología , Estrés Oxidativo , Pirrolidinas , Animales , Corteza Cerebral/metabolismo , Cuerpo Estriado/metabolismo , Modelos Animales de Enfermedad , Hipocampo/metabolismo , Aumento de la Imagen/métodos , Ácido Kaínico , Masculino , Fantasmas de Imagen , Pirrolidinas/farmacocinética , Ratas , Ratas Wistar , Valores de Referencia , Convulsiones/inducido químicamente , Convulsiones/metabolismo , Sensibilidad y EspecificidadRESUMEN
In this paper, we describe sterilization and disinfection of medical wastes contaminated with blood borne-virus, such as Ebola virus, Marburg virus, Crimean-Congo hemorrhagic fever virus, Lassa virus, Hepatitis B virus and Human immunodeficiency virus.
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Desinfección/métodos , Eliminación de Residuos Sanitarios/métodos , Residuos Sanitarios , Esterilización/métodos , Virus , Animales , Patógenos Transmitidos por la Sangre , Infección Hospitalaria/prevención & control , HumanosRESUMEN
To understand the molecular mechanisms underlying normal and abnormal development of two salmonids, masu salmon (Oncorhynchus masou) and rainbow trout (O. mykiss), we used two-dimensional (2-D) electrophoresis to construct a series of 2-D maps during the embryonic period. We identified all visible protein spots on the 2-D map by assigning numbers for masu salmon and rainbow trout, and we determined N-terminal sequences of proteins for one hundred of the spots, that appear at very high concentrations in the whole embryos of masu salmon and rainbow trout. We also characterized embryonic stages according to the periods of appearance of spots. Most of the N-terminal sequences were identical or at least highly similar to partial sequences reported for vitellogenin (Vtg) of O. mykiss. A potential proteolytic processing of Vtg for rainbow trout is discussed in relation to the time of appearance and relative position of Vtg fragments within the complete protein sequence.
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Oncorhynchus/embriología , Proteínas/metabolismo , Proteoma/metabolismo , Secuencia de Aminoácidos , Animales , Electroforesis en Gel Bidimensional/métodos , Endopeptidasas/metabolismo , Datos de Secuencia Molecular , Oncorhynchus/metabolismo , Mapeo Peptídico/métodos , Procesamiento Proteico-PostraduccionalRESUMEN
OBJECTIVES: It is important to elucidate the risks to foreign female prostitutes of HIV infection from their clients. We determined the prevalence of HIV among clients of foreign female prostitutes using anonymous testing of condom semen samples. METHODS: A total of 250 client condom semen samples were collected with client age and nationality by 15 Latin American and 37 Thai female prostitutes in Tokyo from March to May 1995. We screened by ELISA (GENELAVIA MIXT, Pasteur Sanofi Diagnostics) for antibody to HIV 1 and 2, and then confirmed by Western Blot (LAV Blot 1, LAV Blot 2, Sanofi Diagnostics Pasteur) and distinguished by Immuno Blot PEPTI-LAV 1, 2, (Sanofi Diagnostics Pasteur). RESULTS: The nationality of customers was reported as Japanese (74.8%), Iranian (7.6%), Pakistan (5.6%), Indian (2.8%), Taiwanese (2.0%), and Chinese (1.2%) with other nationalities less than 1.0%. Estimated age categories of the clients were < 20 (1.2%), 20-29 (41.2%), 30-39 (36.4%), 40-49 (12.4%), > or = 50 (6.4%) and undetermined (2.4%). Of the 250 samples collected, only 219 were sufficient for testing. Two samples (0.90%, 95% CI = 0.4-2.2%) were HIV 1 positive, both from Japanese clients (1.2% of Japanese clients, 95% CI = 0.5-2.9%). These data suggested that the prevalence of HIV in clients of female prostitutes was relatively high, and can be considered a risk group in Japan. The sentinel surveillance by anonymous of client condom semen samples is a very useful method to quantify HIV prevalence in this risk group.
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Infecciones por VIH/epidemiología , Trabajo Sexual , Síndrome de Inmunodeficiencia Adquirida/epidemiología , Adulto , Recolección de Datos , Emigración e Inmigración , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Semen , Tokio/epidemiologíaRESUMEN
We investigated expression of NGFI-A/zif268 mRNA, reliable marker for neuronal activation in response to stress in the brain of rats pretreated with ethanol. The rats were orally administrated with either 25% sucrose or 20% ethanol (20 ml of kg body weight) 10 min before the onset of the stress. The rats were exposed to immobilization stress for 20 min and quickly decapitated. The brains were extracted and immediately frozen. The level of NGFI-A mRNA was evaluated by in situ hybridization histochemistry. Prior ethanol administration attenuated the immobilization stress-induced upregulation of NGFI-A mRNA level in the neocortex and hippocampus. However, in the paraventricular hypothalamic nucleus, prior administration of ethanol did not affect the upregulation of this gene. These data suggest that ethanol abolishes the forebrain component of the stress response while it fails to attenuate the stress response on a region of the brain that regulates the autonomic nervous system and the hypothalamo-pituitary-adrenal axis. Regional differences in the expression of NGFI-A mRNA may be important for the complex interactions between ethanol and stress.
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Depresores del Sistema Nervioso Central/farmacología , Proteínas de Unión al ADN/efectos de los fármacos , Etanol/farmacología , Proteínas Inmediatas-Precoces , ARN Mensajero/efectos de los fármacos , Estrés Fisiológico/metabolismo , Factores de Transcripción/efectos de los fármacos , Animales , Depresores del Sistema Nervioso Central/sangre , Proteínas de Unión al ADN/metabolismo , Proteína 1 de la Respuesta de Crecimiento Precoz , Etanol/sangre , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Inmovilización/efectos adversos , Masculino , Neocórtex/efectos de los fármacos , Neocórtex/metabolismo , Núcleo Hipotalámico Paraventricular/efectos de los fármacos , Núcleo Hipotalámico Paraventricular/metabolismo , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Sacarosa/farmacología , Factores de Transcripción/metabolismoRESUMEN
A method for electrically detected magnetic resonance (EDMR) measurement at different ESR frequencies under a constant alternating magnetic field has been established wherein the accurate relationship between EDMR signal intensity (from a photoexcited silicon crystal and a silicon diode) and a resonant frequency of 300 to 900 MHz (UHF band) was systematically clarified. EDMR signal intensity from a photoexcited silicon crystal against a resonant frequency fitted the curve of y = a(1 - e(-bx)) well, which approached a constant value at higher frequencies. The increase in the EDMR signal intensity from the silicon diode at higher resonant frequencies was smaller than that from the photoexcited silicon crystal. The difference can be explained by the influence of the skin effect; i.e., the microwaves do not penetrate deep into a highly conductive sample at higher frequencies. EDMR signal intensities of samples vs microwave power were measured at 890 MHz. The EDMR signal intensity from the silicon diode continued to increase as the microwave power was increased, while the signal intensity from the photoexcited silicon crystal saturated within the range. The difference can be similarly explained: due to the skin effect, the microwaves gradually penetrate into the silicon diode as the power increases, so that even when saturation has been reached outside, the microwave field inside the diode does not reach the saturation level.
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Espectroscopía de Resonancia Magnética/métodos , ElectricidadRESUMEN
Free radicals are well-established transient intermediates in chemical and biological processes. Singlet oxygen, though not a free radical, is also a fairly common reactive chemical species. It is rare that singlet oxygen is studied with the electron spin resonance (ESR) technique in biological systems, because there are few suitable detecting agents. We have recently researched some semiquinone radicals. Specifically, our focus has been on bipyrazole derivatives, which slowly convert to semiquinone radicals in DMSO solution in the presence of potassium tert-butoxide and oxygen. These bipyrazole derivatives are dimers of 3-methyl-1-phenyl-2-pyrazolin-5-one and have anti-ischemic activities and free radical scavenging properties. In this work, we synthesized a new bipyrazole derivative, 4,4'-bis(1p-carboxyphenyl-3-methyl-5-hydroxyl)-pyrazole, DRD156. The resulting semiquinone radical, formed by reaction with singlet oxygen, was characterized by ESR spectroscopy. DRD156 gave no ESR signals from hydroxyl radical, superoxide, and hydrogen peroxide. DRD156, though, gives an ESR response with hypochlorite. This agent, nevertheless, has a much higher ability to detect singlet oxygen than traditional agents with the ESR technique.
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Espectroscopía de Resonancia por Spin del Electrón/métodos , Oxígeno/análisis , Dimetilsulfóxido , Radicales Libres/análisis , Indicadores y Reactivos , Pirazoles/síntesis química , Pirazoles/química , Quinonas/síntesis química , Quinonas/química , Especies Reactivas de Oxígeno , Oxígeno Singlete , Soluciones , Marcadores de Spin/síntesis químicaRESUMEN
Particles of HPLC resins are used for the trapping of secreted molecules from a single cell. The basic molecules, e.g., histamine, are secreted from a single RBL-2H3 cell by granule exocytosis and are trapped by cation-exchange HPLC resins outside the cell. Since quinacrine is concentrated into the exocytotic and acidic microgranules in RBL-2H3 cells, which are used as a model cell line of mast cells, we measured the change in the fluorescence intensity of the quinacrine released from the cells and that of molecules trapped on the resin using a videomicroscope. By measuring the increase in the fluorescence intensity of the resins, we can estimate the real time course of molecular secretion from a single cell.