Biomedical subjects

Koichi Inoue

Publications and source records attributed to Koichi Inoue.

At least 37 records · Page 2Linked to original sources

PubMed2005

Characterization of newly cloned variant of rat glycine receptor alpha1 subunit.

Responses to glycine, a major inhibitory neurotransmitter within the nervous system, are mediated by glycine receptors (GlyRs). Here, we report the cloning and analysis of a novel splicing variant of the GlyRalpha1 subunit. This variant, named GlyRalpha1del, has a truncated cytoplasmic region between transmembrane domains (TM)3 and TM4, and compared to other variants, the truncation is contributed by a different acceptor site in exon 9. We transfected GlyRalpha1 or GlyRalpha1del into HEK293 cells, and then examined the glycine-activated currents using a whole-cell patch-clamp recording technique. Maximal currents and current-voltage relationships showed no clear difference between GlyRalpha1del and GlyRalpha1. Moreover, dose-response curves indicated that the EC50 values for glycine differed significantly between the two GlyRalpha1 derivatives, although their Hill coefficients were similar. When present with other isoforms, GlyRalpha1del might alter the response to glycine or to other agonists, as this variant expands the potential heterogeneity among glycine receptors.

Amino Acid Sequence↗

PubMed2005

Detection of embolic particles with the Doppler guide wire during coronary intervention in patients with acute myocardial infarction: efficacy of distal protection device.

OBJECTIVES: We investigated whether embolic particles could be detected as high-intensity transient signals (HITS) with a Doppler guide wire during percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) We also assessed whether these signals could be reduced using a distal protection (DP) device. BACKGROUND: Embolization of thrombi and plaque components to the microcirculation is a major complication of PCI in patients with AMI. Embolic particles running in the cerebral artery are detected as HITS by transcranial Doppler ultrasound. METHODS: We prospectively studied 16 consecutive patients with AMI who underwent direct PCI within 24 h after the onset of symptoms. A PercuSurge GuardWire (MedtronicAVE, Santa Rosa, California) was used as the DP device. Eight patients were randomly assigned to the non-DP group, and the remaining eight were assigned to the DP group. Coronary flow velocity was recorded continuously from before the first balloon inflation to after balloon deflation. RESULTS: All patients in the non-DP group had HITS detected (12 +/- 9 counts) within five consecutive beats (4 +/- 1 beat) after balloon deflation, but none were detected in any of the patients in the DP group. CONCLUSIONS: The Doppler guide wire can be used to visually detect and count emboli as HITS, and the DP device is effective for prevention of distal embolization.

Aged↗

PubMed2005

Prophylactic hepatic irradiation following curative resection of pancreatic cancer.

BACKGROUND/PURPOSE: It is unlikely that adjuvant chemoradiotherapy applied to the pancreatic bed alone significantly improves the survival of patients with resectable pancreatic cancer. The aim of the present study was to determine whether prophylactic hepatic irradiation (PHI) improved patient outcome after the curative resection of pancreatic cancer. METHODS: The study population was comprised of 34 patients (PHI group) who were administered PHI after curative resection of pancreatic cancer between September 1994 and December 2003. The whole liver was irradiated with a total dose of 19.8-22.0 Gy under continuous infusion of 5-fluorouracil. The cumulative rate of liver metastasis and the survival outcomes of the PHI group were compared with those of 31 patients without PHI (non-PHI group) who underwent curative resection of pancreatic cancer. RESULTS: The planned PHI was completed for 32 of the 34 patients. Two patients developed complications that might have been PHI-related. One developed liver abscesses which were successfully managed by percutaneous drainage. The other died of liver failure without recurrence 11 months after the operation. The cumulative incidence of liver metastasis was significantly lower for the PHI group than the non-PHI group (P=0.0455). Patients in the PHI group also survived significantly longer compared to those in the non-PHI group (P=0.0002). CONCLUSIONS: The present findings suggest that PHI is well tolerated and is a potentially effective treatment strategy after curative resection of pancreatic cancer, thereby providing the basis for a randomized controlled trial.

Adult↗

PubMed2005

Evaluation and analysis of exposure levels of di(2-ethylhexyl) phthalate from blood bags.

BACKGROUND: The US FDA and The Ministry of Health, Labor and Welfare of Japan have indicated that the risk assessment of di(2-ethylhexyl) phthalate (DEHP) released from polyvinyl chloride (PVC) medical devices requires immediate attention. In particular, the analysis of the exposure to DEHP from blood bags is very important for medical treatment. However, human exposure to DEHP via blood transfusion remains poorly understood. We evaluated DEHP and mono(2-ethylhexyl) phthalate (MEHP) levels, migration patterns, and metabolism in blood products for the detailed assessment of exposure to DEHP. METHODS: A method that is based on column-switching liquid chromatography-electrospray mass spectrometry (LC-MS) coupled with on-line extraction was used for the direct analysis of DEHP and MEHP in the blood products. From the Japanese Red Cross Society, 78 blood products (red blood cell concentrate: n=18, irradiated red blood cell concentrate: n=18, whole blood: n=18, blood platelet: n=18, and frozen plasma: n=6) were sampled in January 2003 for use in this study. RESULTS: The detection levels of DEHP and MEHP ranged from 1.8 to 83.2 microg/ml and from 0.1 to 9.7 microg/ml, respectively. The levels of MEHP and DEHP in the blood products were increased with increasing storage time. In addition, whole blood products in PVC bags had the highest DEHP levels compared to the other blood products. Our results indicate that the maximum level of human exposure to DEHP released from blood bags is 0.7 mg/kg weight/time. CONCLUSION: This first quantitative evidence may be useful for the risk assessment of DEHP released from blood bags.

Blood Platelets↗

PubMed2004

Development of liquid chromatography-electrospray mass spectrometry for the determination of patulin in apple juice: investigation of its contamination levels in Japan.

Patulin is a mycotoxin produced by mainly Penicillium species, for example, P. expansum, and Aspergillus species. There are several reports of patulin contamination in apple juice. Last year, the Ministry of Health, Labour and Welfare of Japan set the maximum allowable level of patulin in apple juice at 50 ppb and decided that the measurement of patulin levels in apple juice products should be conducted. To this end, a simple, accurate, and selective analytical method for the detection of patulin at levels lower than 5 ppb, the detection limit, is desired. This paper reports the development of an analytical method that employs solid-phase extraction-liquid chromatography-mass spectrometry (SPE-LC-MS). When MS measurements were conducted with the selected ion monitoring (SIM) mode, the pseudomolecular ions at m/z 153 and 156 were used to monitor patulin and (13)C(3)-labeled patulin, respectively. The detection limit (S/N = 3) and the quantification limit (S/N = 10) of patulin at injection levels into LC-MS were 12.5 and 25 pg, respectively. However, when the actual sample was applied for the analysis based on the developed method including the sample preparation, the detection limit (S/N = 3) and quantification limit (S/N = 10) were 2.5 and 5 pg in sample, respectively. The calibration curve obtained for concentrations ranging from 5 to 500 ppb showed good linearity with a coefficient of determination (r (2)) of 0.999. In addition, the recovery was >95% when an internal standard was used. The method was applied to the analysis of 76 apple juice samples from Japan, and as a result, patulin levels ranging from <1.0 to 45 ppb (detection frequency = 15/76) were detected. In this study, it was found that patulin was a greater contaminant in concentration/reduction than in "not from concentrate" apple juice.

Beverages↗

PubMed2004

Malfunction of respiratory-related neuronal activity in Na+, K+-ATPase alpha2 subunit-deficient mice is attributable to abnormal Cl- homeostasis in brainstem neurons.

Na+, K+-ATPase 2 subunit gene (Atp1a2) knock-out homozygous mice (Atp1a2-/-) died immediately after birth resulting from lack of breathing. The respiratory-related neuron activity in Atp1a2-/- was investigated using a brainstem-spinal cord en bloc preparation. The respiratory motoneuron activity recorded from the fourth cervical ventral root (C4) was defective in Atp1a2-/- fetuses of embryonic day 18.5. The C4 response to electrical stimulation of the ventrolateral medulla (VLM) recovered more slowly in Atp1a2-/- than in wild type during superfusion with Krebs' solution, consistent with the high extracellular GABA in brain of Atp1a2-/-. Lack of inhibitory neural activities in VLM of Atp1a2-/- was observed by optical recordings. High intracellular Cl- concentrations in neurons of the VLM of Atp1a2-/- were detected in gramicidin-perforated patch-clamp recordings. The alpha2 subunit and a neuron-specific K-Cl cotransporter KCC2 were coimmunoprecipitated in a purified synaptic membrane fraction of wild-type fetuses. Based on these results, we propose a model for functional coupling between the Na+, K+-ATPase alpha2 subunit and KCC2, which excludes Cl- from the cytosol in respiratory center neurons.

Amino Acid Sequence↗

PubMed2004

Determination of perfluorooctane sulfonate, perfluorooctanoate and perfluorooctane sulfonylamide in human plasma by column-switching liquid chromatography-electrospray mass spectrometry coupled with solid-phase extraction.

We report a method for determining fluorinated organic compounds such as perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA) and perfluorooctanesulfonylamide (PFOSA) in human blood samples by column-switching liquid chromatography-electrospray mass spectrometry. The sample preparation prior to solid phase extraction (Waters Oasis HLB extraction column) involved simply mixing plasma sample with internal standard followed by centrifugation and extraction. The compounds were separated by reversed-phase chromatography with a C(8) column, and detected by mass spectrometry using selected ion monitoring in the negative mode. The average recoveries of PFOS, PFOA and PFOSA ranged from 82.2 to 98.7% (R.S.D.: from 2.0 to 5.2%, n = 6). The limits of quantitation of PFOS, PFOA and PFOSA at signal to noise (S/N = 10) were 0.5, 0.5 and 1.0 ng ml(-1). The method enables the precise determination of standards and can be applied to the detection of PFOS, PFOA and PFOSA in human plasma samples for monitoring human exposure.

Acetates↗

PubMed2004

Stir bar sorptive extraction with in situ derivatization and thermal desorption-gas chromatography-mass spectrometry in the multi-shot mode for determination of estrogens in river water samples.

A novel method for the trace analysis of natural and synthetics estrogens, such as estrone (E1), 17beta-estradiol (E2) and 17alpha-ethynylestradiol (EE), in river water sample was developed, which involved stir bar sorptive extraction (SBSE) with in situ derivatization followed by thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS). The derivatization conditions with acetic acid anhydride and the SBSE conditions such as sample volume and extraction time were investigated. In addition, the single and multi-shot modes in TD were investigated. The detection limits of E1, E2 and EE in river water sample were 0.2, 0.5 and 1 pg ml(-1) (ppt), respectively, in the multi-shot mode using five stir bars. The calibration curves for E1, E2 and EE were linear and had correlation coefficients >0.99. The average recoveries of E1, E2 and EE from all sample volumes were higher than 90% (R.S.D. < 10%) with correction using an added surrogate standard such as estrone-13C4, 17beta-estradiol-13C4 or 17alpha-ethynylestradiol-13C4. This simple, accurate, sensitive and selective analytical method may be applicable to the determination of trace amounts of estrogens in water samples.

Algorithms↗

PubMed2004

Determination of 4-tert.-octylphenol and 4-nonylphenol in laboratory animal feed sample by stir bar sorptive extraction followed by liquid desorption and column-switching liquid chromatography-mass spectrometry with solid-phase extraction.

A novel analytical method has been developed for the determination of 4-tert.-octylphenol (OP) and 4-nonylphenol (NP) in laboratory animal feed samples, which involves stir bar sorptive extraction (SBSE) followed by liquid desorption (LD) and column-switching liquid chromatography-mass spectrometry (CS-LC-MS) with solid-phase extraction (SPE). The method required correction by stable isotopically labeled surrogate standards, deuterium 4-tert.-octylphenol (OP-d) and [2H5] 4-(1-methyl)octylphenol (m-OP-d5). A feed sample was homogenized with methanol by ultrasonication. After centrifugation, the supernatant was subjected to extraction for 120 min at room temperature (25 degrees C) using a stir bar coated with polydimethylsiloxane. After the extraction, the analyte was desorbed from the stir bar by LD using acetonitrile. Then, the liquid sample was analyzed by CS-LC-MS with SPE. The average recoveries from laboratory feed samples spiked with OP and NP at 20 ng g(-1) were 99.5 and 103.8%, respectively, with correction using the added surrogate standards. The limits of quantification were 1 ng g(-1) for OP and 5 ng g(-1) for NP in feed sample. The measurement of OP and NP in commercial laboratory animal feed samples resulted in the detection of sub ng g(-1) NP

Animal Feed↗

PubMed2004

Trace analysis of phenolic xenoestrogens in water samples by stir bar sorptive extraction with in situ derivatization and thermal desorption-gas chromatography-mass spectrometry.

A method for the simultaneous measurement of trace amounts of phenolic xenoestrogens, such as 2,4-dichlorophenol (2,4-DCP), 4-tert-butyl-phenol (BP), 4-tert-octylphenol (OP), 4-nonylphenol (NP), pentachlorophenol (PCP) and bisphenol A (BPA), in water samples was developed using stir bar sorptive extraction (SBSE) with in situ derivatization followed by thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS) analysis. The conditions for derivatization with acetic acid anhydride were investigated. A polydimethylsiloxane (PDMS)-coated stir bar and derivatization reagents were added to 10 ml of water sample and stirring was commenced for 10-180 min at room temperature (25 degrees C) in a headspace vial. Then, the extract was analyzed by TD-GC-MS. The optimum time for SBSE with in situ derivatization was 90 min. The detection limits of 2,4-DCP, BP, OP, NP, PCP and BPA were 2, 1, 0.5, 5, 2 and 2 pg ml(-1), respectively. The method showed good linearity over the concentration ranges of 10, 5, 2, 20, 10 and 10-1000 pg ml(-1) for 2,4-DCP, BP, OP, NP, PCP and BPA, respectively, and the correlation coefficients were higher than 0.99. The average recoveries of those compounds in river water samples were equal to or higher than 93.9% (R.S.D. <7.2%) with correction using the added surrogate standards. This simple, accurate, sensitive and selective method can be used in the determination of trace amounts of phenolic xenoestrogens in river water samples.

Estrogens↗

PubMed2004

Determination of bisphenol A in river water and body fluid samples by stir bar sorptive extraction with in situ derivatization and thermal desorption-gas chromatography-mass spectrometry.

A new method, based on stir bar sorptive extraction (SBSE) with in situ derivatization and thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS) is described for the determination of trace amounts of bisphenol A (BPA) in river water, urine, plasma, and saliva samples. The derivatization conditions with acetic acid anhydride and the SBSE conditions such as sample volumes and extraction time are investigated. Then, the stir bar is subjected to TD followed by GC-MS. The detection limits of BPA in river water, urine, plasma, and saliva samples are 1-5, 20, 100, and 20pgml(-1) (ppt), respectively. Calibration for BPA was shown to be linear with a correlation coefficient of >0.99. The average recoveries of BPA in all samples are higher than 95% (R.S.D. < 10%) with correction using an added surrogate standard, 13C12-bisphenol A. This simple, accurate, sensitive, and selective analytical method may be applicable to the determination of trace amounts of BPA in liquid samples.

Benzhydryl Compounds↗

PubMed2004

Interaction of neuron-specific K+-Cl- cotransporter, KCC2, with brain-type creatine kinase.

gamma-Aminobutyric acid, a major inhibitory neurotransmitter within the adult central nervous system, is also known to be excitatory at early developmental stages due to the elevated intracellular Cl(-) concentration. This functional change is primarily attributable to a K(+)-Cl(-) cotransporter, KCC2, the expression of which is developmentally regulated in neurons. However, little detail information is available concerning the intracellular regulation of KCC2 function. Here, we identify an interaction between KCC2 and brain-type creatine kinase by means of yeast two-hybrid screening. This interaction, which was also detected in cultured cells and brain extracts, might contribute to KCC2-mediated modulation of Cl(-) homeostasis.

Animals↗

PubMed2004

Stir bar sorptive extraction and thermal desorption-gas chromatography-mass spectrometry for the measurement of 4-nonylphenol and 4-tert-octylphenol in human biological samples.

Alkylphenols, 4-nonylphenol (NP) and 4-tert-octylphenol (OP), in human urine and plasma samples were analyzed using stir bar sorptive extraction (SBSE) in combination with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). The method involved correction by stable isotopically labeled surrogate standards, 4-(1-methyl)octylphenol-d5 (m-OP-d5) and deuterium 4-tert-octylphenol (OP-d). A biological sample was extracted for 60 min at room temperature (25 degrees C) using a stir bar coated with a 500 microm thick polydimethylsiloxane (PDMS) layer. Then, the stir bar was analyzed by TD-GC-MS in the selected ion monitoring (SIM) mode without any derivatization step. The average recoveries in human urine and plasma samples spiked with NP and OP at levels of 0.5 and 10 ng ml-1 were between 95.8 and 99.8% with correction using the added surrogate standards. The limits of quantitation were 0.2 ng ml-1 for NP and 0.02 ng ml-1 for OP. We measured the background levels of NP and OP in five human urine and three human plasma samples from healthy volunteers. NP and OP were not detected in all human urine samples (N.D. < 0.2 ng ml-1 for NP, and N.D. < 0.02 ng ml-1 for OP). However, 0.2-0.3 ng ml-1 for NP and 0.1-0.2 ng ml-1 for OP in human plasma samples were observed by this method.

Gas Chromatography-Mass Spectrometry↗

PubMed2004

TNFalpha-induced ATF3 expression is bidirectionally regulated by the JNK and ERK pathways in vascular endothelial cells.

ATF3 (Activating transcription factor 3), a member of the CREB/ATF family, can be induced by stress and growth factors in mammalian cells, and is thought to play an important role in the cardiovascular system. However, little is currently known about how the induction of ATF3 is regulated, except that the JNK pathway is involved. Here, we investigated the differential roles of the MAPK pathways involved in TNFalpha (tumour necrosis factor alpha)-induced ATF3 expression in vascular endothelial cells. In human umbilical vein endothelial cells, the expression of constitutively active MKK7 (MAPK kinase 7) increased the number of ATF3-positive cells, and dominant negative MKK7 suppressed the TNFalpha-induced expression of ATF3, indicating a requirement for the JNK pathway. In contrast, the expression of constitutively active or dominant negative MEK1/2 (MAPK/ERK kinase 1/2) suppressed or enhanced TNFalpha-mediated induction of ATF3, respectively. In support of this, the MEK1/2 specific inhibitor U0126 enhanced the expression of ATF3 induced by TNFalpha. Furthermore, the ERK pathway inhibits the TNFalpha-mediated induction of ATF3 mRNA, but not its stability, suggesting the involvement of ERK activity in the transcriptional regulation of the ATF3 gene. Our results suggest that TNFalpha-induced ATF3 gene expression is bidirectionally regulated by the JNK and ERK pathways in vascular endothelial cells.

Activating Transcription Factor 3↗

PubMed2004

Perfluorooctane sulfonate (PFOS) and related perfluorinated compounds in human maternal and cord blood samples: assessment of PFOS exposure in a susceptible population during pregnancy.

Fluorinated organic compounds (FOCs), such as perfluorooctane sulfonate (PFOS), perfluoro-octanoate (PFOA), and perfluorooctane sulfonylamide (PFOSA), are widely used in the manufacture of plastic, electronics, textile, and construction material in the apparel, leather, and upholstery industries. FOCs have been detected in human blood samples. Studies have indicated that FOCs may be detrimental to rodent development possibly by affecting thyroid hormone levels. In the present study, we determined the concentrations of FOCs in maternal and cord blood samples. Pregnant women 17-37 years of age were enrolled as subjects. FOCs in 15 pairs of maternal and cord blood samples were analyzed by liquid chromatography-electrospray mass spectrometry coupled with online extraction. The limits of quantification of PFOS, PFOA, and PFOSA in human plasma or serum were 0.5, 0.5, and 1.0 ng/mL, respectively. The method enables the precise determination of FOCs and can be applied to the detection of FOCs in human blood samples for monitoring human exposure. PFOS concentrations in maternal samples ranged from 4.9 to 17.6 ng/mL, whereas those in fetal samples ranged from 1.6 to 5.3 ng/mL. In contrast, PFOSA was not detected in fetal or maternal samples, whereas PFOA was detected only in maternal samples (range, < 0.5 to 2.3 ng/mL, 4 of 15). Our results revealed a high correlation between PFOS concentrations in maternal and cord blood (r2 = 0.876). However, we did not find any significant correlations between PFOS concentration in maternal and cord blood samples and age bracket, birth weight, or levels of thyroid-stimulating hormone or free thyroxine. Our study revealed that human fetuses in Japan may be exposed to relatively high levels of FOCs. Further investigation is required to determine the postnatal effects of fetal exposure to FOCs. Key words: cord blood, fluorinated organic compounds, human, PFOA, PFOS, PFOSA, pregnancy.

Adolescent↗

PubMed2004

A case of atrial septal defect complicated by autoimmune hemolytic anemia.

Open heart surgery is rarely performed on patients with heart disease complicated by autoimmune hemolytic anemia (AIHA) with the aid of an artificial heart-lung machine. We successfully performed radical open heart surgery on an atrial septal defect (ASD) patient with the complication of AIHA.

Anemia, Hemolytic, Autoimmune↗

PubMed2003

Genistein administration decreases serum corticosterone and testosterone levels in rats.

The phytochemical flavonoid genistein has been shown to act as a potent competitive inhibitor of human adrenocortical 3beta-hydroxysteroid dehydrogenase and cytochrome P450 21-hydroxylase activities in vitro [J. Steroid Biochem. Molec. Biol. 2002; 80: 355-363]. In the present study, we evaluated the effects of large amounts of genistein continuously administered to weanling rats, particularly on steroidogenesis at the pubertal stage in vivo. Serum concentrations of free and total genistein were significantly higher in the 40 mg/kg genistein administration group when compared with the control group. In genistein administered rats, adrenal weight was significantly higher. Furthermore, a clear expansion of cells was observed in hematoxylin and eosin stained tissue at the zona fasciculata and zona reticularis of the adrenal cortex. However in the testis, no differences in weights or histologic changes were observed. Serum corticosterone concentration significantly decreased to 50% of control levels by 40 mg/kg genistein administration and testosterone also tended to decrease with this dose of genistein. On the other hand, although serum follicle stimulating hormone was unchanged, adrenocorticotropic hormone and luteinizing hormone levels increased with genistein administration. These results suggest a significant effect of genistein on steroidogenesis in the adrenal gland and testis of rats, and this effect appeared to be more evident on steroid production in adrenals than in testis in vivo.

Adrenal Glands↗

PubMed2003

Size-exclusion flow extraction of bisphenol A in human urine for liquid chromatography-mass spectrometry.

We report an approach for assessing human exposure to bisphenol A (BPA), which involves measuring the glucuronide in urine sample that were subjected to a novel size-exclusion flow extraction method. The present approach includes the addition of 13C(12)-BPA, enzymatic deconjugation, and the proposed sample preparation method. The sample solution is separated and detected by liquid chromatography-mass spectrometry (LC-MS). The following are used for the LC-MS: a reversed-phase separation column, electrospray ionization (ESI), negative mode, and single ion monitoring (SIM) with m/z 227 for BPA and m/z 239 for 13C(12)-BPA. The detection limit was 0.1 ng ml(-1) and the calibration curves (0.45-90 ng ml(-1)) had correlation coefficients exceeding 0.999. To urine samples requiring deglucuronidation, beta-glucuronidase was added followed by incubation at 37 degrees C for 3 h. After the enzymatic treatment, the samples were subjected to the extraction in the reversed-phase (ODS) and size-exclusion (GPC) modes. It was possible to extract, clean up and concentrate BPA in a single run of 20 min by means of the novel extraction method. The method enables the determination of standards and may be applied to the detection of trace amounts of BPA in human urine samples.

Adult↗