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Biomedical subjects

Yoko Kawamura

Publications and source records attributed to Yoko Kawamura.

17 recordsLinked to original sources
PubMed2006

Estrogenic activities of chemicals related to food contact plastics and rubbers tested by the yeast two-hybrid assay.

Food contact plastics and rubbers possibly contain many kinds of chemicals such as monomers, oligomers, additives, degradation products of polymers and additives, and impurities. Among them, bisphenol A, nonylphenol, benzylbutyl phthalate, styrene oligomers and hydroxylated benzophenones have been reported to possess estrogenic activities. In this study, other chemicals related to food contact plastics and rubbers, and their metabolites induced by the S9-mixture were tested for their estrogenic activities using the yeast two-hybrid assay. Among the 150 chemicals, 10 chemicals such as bis(4-hydroxyphenyl) methane, 4-cyclohexylphenol, 4-phenylphenol, 4,4'-isopropylidenediphenol alkylphosphite, two type of styrenated phenol (including mono type), tris(nonylphenyl) phosphite, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone and 2,4-diphenyl-4-methyl-1-pentene, their metabolites and the metabolites of 6 other chemicals, such as 2-(phenylmethyl) phenol, styrenated phenol (di and tri type), 1-(N-phenylamino)naphthalene, 4-tert-butylphenylsalicylate, nonylphenol ethoxylates and 2-methyl-6-tert-butylphenol, displayed estrogenic activities. All of them contained a phenol group in their chemical structures or formed one easily by hydrolysis or metabolism. However, most of the chemicals related to food contact plastics and rubbers, and their metabolites did not show any estrogenicity.

Antioxidants↗
PubMed2006

[Survey of epoxidized soybean oil in cap sealing for bottled foods].

Epoxidized soybean oil (ESBO) was surveyed in the 103 samples of cap sealing for bottled foods on the Japanese market. Most of the sealings were made of polyvinyl chloride, while a few were made of polyethylene or acrylic resin. All the sealings contained ESBO in the range of 0.006-42.4%. Sealings for baby food, jam, etc. contained higher levels of ESBO, though those for beverages contained lower levels. Sealings in lug caps and press-on twist caps contained higher levels of ESBO, though that in pilfer-proof caps contained lower levels. Some sealings in screw caps and lug caps also contained other plasticizers, for example, di-2-ethylhexyl phthalate and diisononyl phthalate, and their ESBO contents were 1/10 of those in sealings containing only ESBO. In this survey, ESBO was the most common plasticizer in cap sealing resin for bottled foods on the Japanese market.

Diethylhexyl Phthalate↗
PubMed2006

[Determination of epoxidized soybean oil in bottled foods].

A determination method for epoxidized soybean oil (ESBO) in bottled foods was developed and used to survey bottled foods on the Japanese market. The amount of sample required was decreased to 20 g and the standard addition method was adopted for the quantification, because lipid in foods interrupted the hydrolysis of ESBO. The recoveries were 87.1 and 98.9% and the determination limit was 5.0 microg/g for a 20 g sample, be cause lipid in foods interupted the hydrolysis of ESBO. The recoveries using the internal standard method varied widely, because hydrolysis of the internal standard, cis-11,14-eicosadienoic acid ethyl ester, was affected more than that of ESBO by coexisting lipid in the sample. ESBO was not detected in any of the bottled baby food samples examined (14 samples), though it had been frequently detected in previous European surveys. This difference may be related to the low fat content and low fluidity of the bottled baby foods retailed in Japan. On the other hand, ESBO was detected at levels of 25.7-494.0 microg/g in liver paste, pasta sauce, Sungan in spicy oil, and spicy oil. These foods had higher fat content and higher fluidity. However, ESBO intake from these foods appears unlikely to exceed the TDI in the EU (1 mg/kg bw/day).

Dietary Fats↗
PubMed2006

[Contents of eight harmful elements in baby toys and their migration tests].

Levels of eight harmful elements, i.e., antimony, arsenic, barium, cadmium, chromium, lead, mercury and selenium, were investigated in 45 baby toys and 10 paints, which were mainly made of polyvinyl chloride. All samples contained barium at levels of 0.3-3,700 mg/kg, several samples contained cadmium (0.2-26 mg/kg), chromium (0.5-280 mg/kg) and lead (1.5-1,300 mg/kg), and one sample contained antimony (5.3 mg/kg). They might have been used as colorants of the toy materials and paints. They were then evaluated using the migration test of ISO 8124-3, in which samples were ground up, and then soaked in 0.07 mol/L HCl at 37 degrees C for two hours. Barium, cadmium, chromium and lead migrated from some of the samples, but at levels lower than the migration limits required by ISO 8124-3. Compared with the Japanese official method, the ISO method resulted in higher migration, but there are significant differences in the migration limits, test method, and so on between them. Further investigation is needed in this area.

Antimony↗
PubMed2006

[Determination of epoxidized soybean oil and linseed oil in wrapping film and cap sealing].

A determination method was developed for epoxidized soybean oil (ESBO) and epoxidized linseed oil (ELO), which are used as plasticizers and/or stabilizers, in wrapping film and cap sealings. The ESBO method reported by Castle et al. was improved. Samples were extracted with acetone-hexane (3: 7), transmethylated under alkaline conditions, then derivatized to the 1,3-dioxolanes and analyzed by GC/MS. The recoveries of spiked ESBO and ELO were between 92.6% and 104.4%. The determination limits were 0.01 mg/g for ESBO and 0.02 mg/g for ELO in the wrapping film, and 0.04 mg/g and 0.08 mg/g in the cap sealing. ESBO and ELO were surveyed in 10 samples each of wrapping film and cap sealings currently available on the Japanese market. ESBO was found at 34.7-82.8 mg/g in polyvinyl chloride (PVC) wrapping films and at 5.47-399 mg/g in cap sealings. ELO was detected at 8.6-11.4 mg/g in polyvinylidene chloride (PVDC) wrapping films, and at 46.4 mg/g in a PVC wrapping film.

Excipients↗
PubMed2006

[Migration of bisphenol A and benzophenones from paper and paperboard products used in contact with food].

Migration of bisphenol A (BPA) and benzophenones, i.e., benzophenone (BZ), 4-(dimethylamino)benzophenone (DMAB), Michler's ketone (MK) and 4,4'-bis(diethylamino)benzophenone (DEAB), from 21 paper and paperboard products (15 recycled paperboard boxes and 6 virgin paper products) used in contact with food was examined. Migration levels of compounds from recycled paperboard were compared under various food-simulating conditions. BPA showed the highest migration into 20% ethanol and benzophenones into 95% ethanol. No compounds migrated from virgin paper products, but compounds did migrate into food simulants from recycled paperboard food boxes. BPA migrated into 20% ethanol from all recycled paperboard food boxes between 1.0 and 18.7 ng/mL. Into 95% ethanol, migration of BZ was observed in 8 samples (1.0-18.9 ng/mL), DMAB in 12 samples (1.2-3.7 ng/mL), MK in 13 samples (1.9-9.0 ng/mL), and DEAB in 13 samples (1.0-10.6 ng/mL). The highest migration level was 27.2 ng/mL and most of the migration levels were below 10 ng/mL. These values are sufficiently low compared with the TDI and NOAEL levels. Moreover, the amount of food in daily meals that comes into contact with paperboard products is relatively small. Consequently, it was concluded that there was no safety concern regarding the tested compounds in recycled paperboard food boxes.

Benzhydryl Compounds↗
PubMed2005

[Metals in recycled polyethylene terephthalate and discrimination method for its use].

Metals in recycled polyethylene terephthalate (PET) were analyzed by ICP-MS following microwave digestion with nitric acid. Physically and superclean-like recycled PET contained both Ge and Sb, and sometimes contained Co, P or Si. In contrast, the chemically recycled PET contained only Ge or Sb, and some samples contained Co. The recycled PETs did not contain Pb or Cd. Ge and Sb were catalysts of the polymerization, and the other metals also originated from the PET resin as additives. It was concluded that there is no safety concern about metals in recycled PET. It became clear that the presence of both Ge and Sb could identify products formed using physically or superclean-like recycled PET. According to this discrimination method, about half of the sheet molding products used recycled PET.

Antimony↗
PubMed2005

[Analysis of residual volatiles in recycled polyethylene terephthalate].

The residual volatiles in recycled polyethylene terephthalate (PET) were analyzed using headspace/GC/MS. Recycled PET samples were made from PET bottles used for beverages, alcohol and soy sauce, and they were recycled in physical recycling plants, chemical recycling plants and superclean-like recycling trials. The physically recycled PET flakes contained small amounts of volatiles such as ethanol, limonene, 2-methyl-1,3-dioxolane, acetone, octanal and nonanal. Most of them originated from foods packed in bottles, and only 2-methyl-1,3-dioxolane was derived from polymer impurities. In contrast, the superclean-like or chemically recycled PET contained no detectable volatiles, like new PET pellets. The PET sheets shaped from physically recycled PET had no detectable volatiles. Not only the chemically and superclean-like recycled PET, but also the physically recycled PET contained no hazardous volatiles. It was concluded that there is no safety concern about volatiles in recycled PET, for the present use.

Acetone↗
PubMed2005

[Analysis of formaldehyde, acetaldehyde and oligomers in recycled polyethylene terephthalate].

Formaldehyde (FA), acetaldehyde (AA) and oligomers in recycled polyethylene terephthalate (PET) were analyzed by HPLC. All of the physically recycled PET contained detectable levels of FA, AA and oligomers, and the levels were almost the same as in used bottles. Most superclean-like and chemically recycled PET contained lower levels than new pellets. These compounds showed no decrease upon physical recycling, but showed a marked decrease upon superclean-like recycling. In PET sheets made using physically recycled PET, FA was decreased, though AA was increased by the sheeting process as same as new one. FA, AA and oligomers originated from PET resin and their levels in recycled products were almost equivalent to those in new products. It was concluded that there is no particular safety concern about their presence in recycled PET.

Acetaldehyde↗
PubMed2005

[Headspace GC/MS analysis of residual vinyl chloride and vinylidene chloride in polyvinyl chloride and polyvinylidene chloride products].

A headspace GC/MS analysis method for the simultaneous determination of residual vinyl chloride (VC) and vinylidene chloride (VDC) in polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC) products was developed. A test sample was swelled overnight with N,N-dimethylacetamide in a sealed vial. The vial was incubated for 1 hour at 90 degrees C, then the headspace gas was analyzed by GC/MS using a PLOT capillary column. The recoveries from spiked PVC and PVDC samples were 90.0-112.3% for VC and 85.2-108.3% for VDC. The determination limits were 0.01 microg/g for VC and 0.06/microg/g for VDC, respectively. By this method, VC was detected in two PVC water supply pipes at the levels of 0.61 and 0.01 microg/g. On the other hand, VC and VDC were not detected in any of the food container-packages or toys tested.

Dichloroethylenes↗
PubMed2004

Gastric MALT lymphomas are divided into three groups based on responsiveness to Helicobacter Pylori eradication and detection of API2-MALT1 fusion.

Gastric MALT lymphoma shows unique features including regression by Helicobacter pylori eradication and API2-MALT1 fusion. We performed a molecular and clinicopathologic study for 115 cases. All eradication-responsive cases were devoid of API2-MALT1 fusion. All tumors positive for the fusion and all negative for H. pylori infection were nonresponsive to the eradication. Consequently, gastric MALT lymphomas were divided into three groups: Eradication-responsive and fusion-negative (group A, n = 72), eradication-nonresponsive and fusion-negative (group B, n = 22), and eradication-nonresponsive and fusion-positive (group C, n = 21). Group A tumors were characterized by low clinical stage and superficial gastric wall involvement, and group C tumors by low H. pylori infection rate, advanced clinical stage, and nuclear BCL10 expression. All group C tumors showed exclusively low-grade histology. Group B tumors, which have not been well recognized, frequently showed nodal involvement, deep gastric wall involvement, and advanced clinical stage, and sometimes an increased large cell component. A multivariate discriminant analysis revealed that responsiveness to the eradication could be predicted accurately by negative API2-MALT1 fusion, positive H. pylori infection, low clinical stage, and superficial gastric wall invasion, the former being the most important factor for the prediction. This 3-group categorization may be helpful for a comprehensive understanding of gastric MALT lymphoma.

Adaptor Proteins, Signal Transducing↗
PubMed2004

Possible relationship between Helicobacter pylori infection and cap polyposis of the colon.

BACKGROUND: Cap polyposis is a rarely encountered disease characterized by multiple distinctive inflammatory colonic polyps located from the rectum to the distal colon. The etiology of this disease is still unknown, and no specific treatment has been established. AIM: We report three cases of cap polyposis that were cured following eradication therapy for Helicobacter pylori infection. METHODS AND RESULTS: Three women were referred to Shinshu University Hospital because of mucoid and/or bloody diarrhea. Laboratory data showed hypoproteinemia in all cases; markers of inflammation such as C-reactive protein were negative. Colonoscopy revealed multiple sessile polyps with mucus adherent on the apices of the mucosal folds in the rectum and/or the sigmoid colon. The intervening mucosa was normal. Microscopic examinations of biopsy specimens taken from sessile polyps revealed inflamed mucosa with elongated tortuous crypts attenuated towards the mucosal surface. A granulation tissue 'cap' was observed on the surface of the mucosa. Various treatments were unsuccessful, including administration of metronidazole or prednisolone, avoidance of straining at defecation, and surgical or endoscopic resection. All were diagnosed with H. pylori infection in the stomach. Helicobacter pylori was not detected in the biopsy specimens from the colonic inflammatory polyps by immunohistochemical study using polyclonal anti-H. pylori antibody. After successful eradication therapy the clinical symptoms improved. Disappearance of cap polyposis was confirmed by colonoscopy in all three cases. CONCLUSION: We speculate that H. pylori infection might play a role in the pathogenesis of cap polyposis.

Adult↗
PubMed2003

[Identification of migrants from nitrile-butadiene rubber gloves].

Polyvinyl chloride gloves containing di(2-ethylhexyl) phthalate are restricted for food contact use. In their place, disposable gloves made from nitrile-butadiene rubber (NBR) are used in contact with foodstuffs. Some unknown substances were found to migrate into n-heptane from NBR gloves. By GC/MS, HR-MS and NMR, their chemical structures were confirmed to be 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (used as a plasticizer), 4,4'-butylidenedi(6-tert-butyl-m-cresol), a mixture of styrenated phenols consisting of 2-(alpha-methylbenzyl)phenol, 4-(alpha-methylbenzyl)phenol, 2,6-di(alpha-methylbenzyl)phenol, 2,4-di(alpha-methylbenzyl)phenol and 2,4,6-tri(alpha-methylbenzyl)phenol (used as antioxidants), and 2,4-di-tert-butylphenol, which seems to a degradation product of antioxidant. Migration levels of these compounds were 1.68 micrograms/cm2 of 2,4-di-tert-butylphenol, 2.80 micrograms/cm2 of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, 46.08 micrograms/cm2 of styrenated phenols and 4.22 micrograms/cm2 of 4,4'-butylidenedi(6-tert-butyl-m-cresol) into n-heptane, respectively. The content of total styrenated phenols was 6,900 micrograms/g in NBR gloves.

Antioxidants↗
PubMed2003

[Determination method of tricresyl phosphate in polyvinyl chloride].

A simple and rapid method using HPLC was developed for the determination of tricresyl phosphate (TCP) in polyvinyl chloride (PVC) articles. A test sample was extracted with acetonitrile at 37 degrees C overnight. The extract solution diluted with an equivalent amount of water was applied to a Sep-Pak C18 cartridge, and TCP was eluted with acetonitrile-water (2:1) mixture. The eluate was analyzed by HPLC with an Inertsil Ph-3 column, using 65% acetonitrile/water as the mobile phase, with UV detection (264 nm). The calibration curve was rectilinear from 0.5 to 100 micrograms/mL. The recoveries of TCP added to various kinds of PVC articles at the level of 1,000 micrograms/g were 84.7-98.6%. The determination limit of TCP was 50 micrograms/g in samples. This method was applied to products including 3.1, 6.6 and 8.8% TCP and the recoveries of TCP were 87.3-91.4%. This method is very simple, and it seems suitable for a regulatory test.

Chromatography, High Pressure Liquid↗
PubMed2003

[Estimation of daily oral exposure to phthalates derived from soft polyvinyl chloride baby toys].

Daily oral exposure of babies to phthalate was estimated on the basis of the mouthing time of infants and the oral concentration of diisononyl phthalate (DINP) released from polyvinyl chloride (PVC) toy specimens. Total mouthing time, including the use of pacifiers, ranged widely from 11.4 min to 351.8 min with the mean of 105.3 +/- 72.1 min. The mean of the total mouthing time without pacifiers was 73.9 +/- 32.9 min. The average amount of DINP in saliva was 92.4 +/- 56.8 micrograms/10 cm2/hr, ranging from 13.2 micrograms/10 cm2/hr to 240.4 micrograms/10 cm2/hr. The exposure of phthalate in two different trials was estimated by the method of Monte Carlo simulation, one with the total mouthing time with pacifiers and the other with the total mouthing time without pacifiers. The average exposure in the former trial was 21.4 micrograms/kg/day and the 95th percentile was 65.8 micrograms/kg/day, while in the latter it was 14.8 micrograms/kg/day and the 95th percentile was 35.7 micrograms/kg/day.

Humans↗
PubMed2002

[Identification of unknown substances in polyvinyl chloride gloves containing non-phthalate plasticizers].

The use of polyvinyl chloride gloves containing di(2-ethylhexyl) phthalate for food contact applications is restricted. In their place, polyvinyl chloride gloves containing non-phthalate plasticizers (PVC-NP) have been introduced. They contained unknown substances, so they were studied by GC/MS, HR-MS and NMR. The chemical structures of the unknown substances were confirmed to be diethylene glycol dibenzoate, triethylene glycol dibenzoate, dipropylene glycol dibenzoate, and alkylsulfonic acid phenyl ester, which are plasticizers. Including di-isononyl adipate, the contents of the plasticizers were 37.5-48.9% in the PVC-NP gloves, and their migration levels were 1,010-1,390 ppm into n-heptane. These are very high levels. These plasticizers are not widely used for food contact polyvinyl chloride throughout the world, and they have also not been registered as self-standards by Japanese manufacturers. Careful consideration will be necessary for the selection of a suitable plasticizer substitute.

Gas Chromatography-Mass Spectrometry↗