Publications by authors named "Yumiko Okada"

31 Publications

Bacterial Distribution and Community Structure in Beef Cattle Liver and Bile at Slaughter.

J Food Prot 2021 Nov 24. Epub 2021 Nov 24.

National Institute of Health Sciences 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki, JAPAN Kanagawa 210-9501 +81442706563.

In this study, the distribution of hygienic indicator bacteria in cattle livers and bile was examined at slaughterhouses. First, 127 cattle livers with gallbladders were carefully eviscerated from the carcasses at 10 slaughterhouses. Microbiological examination showed that 9 bile (7.1%) and 19 liver parenchyma (15.0%) samples were positive for the family Enterobacteriaceae (EB) with means ± SD of 3.68 ± 4.63 log CFU/mL and 1.59 ± 2.47 log CFU/g, respectively; thus, bacterial contamination was apparent even at the postevisceration stage. Subsequently, 70 cattle livers were obtained at the postprocessing/storage stage from 7 of the ten slaughterhouses; microbiological analysis revealed greater means of EB in the liver parenchyma (means ± SD of 3.00 ± 3.89 log CFU/g, P =0.011) than those at postevisceration stage, suggesting that bacterial dissemination and/or replication occurred in the liver parenchyma during processing and storage. According to 16S rRNA ion semiconductor sequencing analysis of representative samples from 12 cattle, Proteobacteria , Firmicutes , and Actinobacteria were dominant in both the parenchyma and bile, in which EB/ Escherichia coli were predominate among EB-rich livers. These results suggest that bile plays a role as a vehicle for bacterial transmission to the liver parenchyma. This is the first study to demonstrate bacterial distribution and community structure in the liver and biliary microecosystem of cattle at slaughter. Our data provide possible implication of EB testing in bile to screen cattle livers contaminated with high levels of fecal indicator bacteria.
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http://dx.doi.org/10.4315/JFP-21-288DOI Listing
November 2021

Anterior segment dysmorphogenesis of the eye and glaucoma in MG-W gerbils.

J Toxicol Pathol 2021 Jul 18;34(3):245-249. Epub 2021 Apr 18.

Gotemba Research Institute, BoZo Research Center Inc., 1284 Kamado, Gotemba Shizuoka, 412-0039, Japan.

Unilaterally swollen eyes were histopathologically characterized in four MG-W gerbils. The primary lesions resided in the anterior segment of the eye where neural crest cells play a critical role in embryonic development. They included indistinct filtration angle, unformed canal of Schlemm, hypoplastic iris, and ciliary body. The findings noted in the retina, optic nerve, optic tract, and lateral geniculate nucleus were consistent with the lesions induced following the persistent elevation of intraocular pressure as a result of insufficient drainage of aqueous humor. Thus, the present cases observed in the eyes of MG-W gerbils exemplified the anterior segment dysmorphogenesis associated with inadequate neural crest migration or differentiation, leading to subsequent glaucoma.
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http://dx.doi.org/10.1293/tox.2020-0090DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8280303PMC
July 2021

Meningitis and brain abscess formation caused by Cronobacter malonaticus sequence type 440 in a full-term neonate.

J Infect Chemother 2021 Nov 25;27(11):1648-1652. Epub 2021 Jun 25.

Division of Infectious Disease, Department of Pediatrics, Hyogo Prefectural Kobe Children's Hospital, Japan.

Cronobacter spp. cause serious diseases, such as necrotizing enterocolitis, bacteremia, and meningitis in neonates and infants. Most Cronobacter-associated meningitis is reportedly due to C. sakazakii and the majority of infections caused by C. malonaticus occur in adults and are less severe. We report the case of meningitis and brain abscess caused by C. malonaticus Sequence Type (ST) 440 in a healthy full-term neonate. We should consider the possibility that full-term neonates may develop meningitis due to C. malonaticus and treat appropriately because its mortality rate is very high, and survivors are usually left with severe neurologic impairment. In addition, C. malonaticus ST440 may have virulence factors that cause neonatal meningitis akin to the previous report of meningitic ST307 strain.
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http://dx.doi.org/10.1016/j.jiac.2021.06.002DOI Listing
November 2021

Advanced paternal age alone does not adversely affect pregnancy or live-birth rates or sperm parameters following intrauterine insemination.

Reprod Med Biol 2018 Oct 24;17(4):459-465. Epub 2018 Jul 24.

Division of Reproductive Medicine Center of Maternal-Fetal, Neonatal and Reproductive Medicine National Center for Child Health and Development Tokyo Japan.

Purpose: This study aimed to evaluate the effect of advanced paternal age on pregnancy outcomes and sperm parameters following intrauterine insemination (IUI). We used IUI data rather than assisted reproductive technology data, which might mask the effects of sperm impairments.

Methods: We retrospectively analyzed 1576 IUI cycles in women under 40 years old between April 2012 and May 2016 at the National Center for Child Health and Development in Japan. The main outcomes were clinical pregnancy and live birth.

Results: The mean male age was significantly lower in cycles that resulted in pregnancy compared with those without pregnancy (38.0 vs 39.1 years; <0.001), with a similar trend for live-birth cycles. However, there was no relationship between advanced paternal age and pregnancy outcomes after adjusting for confounding factors and correlations within patients using generalized estimating equations, and the age of the female partner was the only factor affecting pregnancy rate. Furthermore, advanced paternal age had no effect on sperm parameters.

Conclusions: Advanced paternal age alone does not adversely affect pregnancy or live-birth rates or sperm parameters following IUI.
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http://dx.doi.org/10.1002/rmb2.12222DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6194307PMC
October 2018

Comparison of Chromogenic Selective Media for the Detection of Cronobacter spp. (Enterobacter sakazakii).

Biocontrol Sci 2018 ;23(1):27-33

Department of Food Bioscience and Biotechnology, College of Bioresource Science, Nihon University.

 The four types of chromogenic selective media that are commercially available in Japan were compared for establishing a Japanese standard method for detecting Cronobacter spp. based on ISO/TS 22964:2006. When assessed using 9 standard Cronobacter spp. strains and 29 non-Cronobacter strains, Enterobacter sakazakii isolation agar, Chromocult Enterobacter sakazakii agar, CHROMagar E. sakazakii, and XM-sakazakii agar demonstrated excellent inclusivity and exclusivity. Using the ISO/TS 22964:2006 method, the recovered numbers of 38 Cronobacter spp. strains, including 29 C. sakazakii isolates obtained from each medium, were equivalent, indicating that there was no significant difference (p > 0.05) among the four types of chromogenic selective media. Thus, we demonstrated that these four chromogenic selective media are suitable alternatives when using the standard method for detecting Cronobacter spp. in Japan, based on the ISO/TS 22964:2006.
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http://dx.doi.org/10.4265/bio.23.27DOI Listing
September 2018

Comparative toxicity of dinophysistoxin-1 and okadaic acid in mice.

J Vet Med Sci 2018 Apr 1;80(4):616-619. Epub 2018 Mar 1.

Division of Biomedical Food Research, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa 210-9501, Japan.

The mouse bioassay for diarrhetic shellfish poisoning toxins has been used worldwide. In this study, dinophysistoxin-1 (DTX-1) and okadaic acid (OA) were compared for toxicity. The lethality rate increased and the median survival time decreased in a dose-dependent manner in both DTX-1 and OA. The median lethal dose value was 150.4 µg/kg (95% confidence interval=130.1-171.2 µg/kg) for DTX-1 and 185.6 µg/kg (95% confidence interval=161.2-209.6 µg/kg) for OA. The toxicity equivalent factor 1:1 has been used for OA and DTX-1 in the EU and Japan. Thus, it may be considered that toxicity potential of DTX-1 has remained underestimated as compared to that of OA and DTX-1 might be more toxic than OA.
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http://dx.doi.org/10.1292/jvms.17-0377DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5938189PMC
April 2018

Extracranial internal carotid artery dissection caused by compression from a giant osteophyte due to atlantoaxial osteoarthritis: case report.

J Neurosurg Spine 2017 Oct 12;27(4):410-414. Epub 2017 May 12.

Department of Neurosurgery, Suisyoukai Murata Hospital, Osaka.

Deformed osseous structures have been reported as rare causes of extracranial internal carotid artery (ICA) dissection, including the styloid process and the hyoid bone. Here, the authors describe the first known case of symptomatic ICA dissection caused by a giant osteophyte due to atlantoaxial osteoarthritis. The left ICA was fixed at the skull base and at the ICA portion compressed by the osteophyte, and it was highly stretched and injured between the two portions during neck rotation. The patient was successfully treated with ligation of the affected ICA following balloon test occlusion. Atlantoaxial osteoarthritis should be considered in the differential diagnosis of ICA dissection in patients with a severely deformed cervical spine.
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http://dx.doi.org/10.3171/2017.1.SPINE161047DOI Listing
October 2017

Ability of NT-pro-BNP to Diagnose Cardioembolic Etiology in Patients with Acute Ischemic Stroke.

Osaka City Med J 2016 12;62(2):95-102

Background Cardioembolic stroke (CE) is usually associated with a larger ischemic area leading to higher morbidity and mortality rates. No biomarkers for CE are available, which causes difficulty in differential diagnosis of CE from other subtypes of acute ischemic stroke.

Methods: We prospectively evaluated consecutive patients with acute ischemic stroke to identify biomarkers that could distinguish between CE and other subtypes of acute ischemic stroke. Etiological diagnoses were identified according to the National Institute of Neurological Disorders and Stroke (NINDS) 111 classification using clinical examinations, computed tomography (CT), magnetic resonance imaging (MRI), cardiac evaluations, and other tests. The biomarkers N-terminal pro-brain natriuretic peptide (NT-pro-BNP), Thrombin-Antithrombin III Complex (TAT), and D-dimer were determined in blood samples collected within 48 hours of onset and compared between groups with and without CE. Non- CE consisted of atherothrombotic brain infarction (ATBI), lacunar infarction (LI), and other stroke subtypes of unknown cause (other).

Results: This study included 279 patients diagnosed with acute ischemic stroke. Serum levels of NT-pro- BNP were significantly higher in those with than in those without CE stroke (p<0.0001). Analysis of receiver operating characteristics (ROC) curves indicated that an NT-pro-BNP cutoff of 332 pg/mL provided optimal sensitivity (98.3%) and specificity (75.8%) for distinguishing CE from non-CE.

Conclusions: Serum levels of NT-pro-BNP may help in diagnosis of CE during the acute phase and thus allow appropriate therapy t6 prevent subsequent cardiogenic stroke.
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December 2016

Intraoperative Transcranial Motor-Evoked Potentials Predict Motor Function Outcome in Intracerebral Hemorrhage Surgery.

World Neurosurg 2016 Jun 26;90:518-523. Epub 2016 Mar 26.

Department of Neurosurgery, Suisyoukai Murata Hospital, Osaka City, Osaka, Japan.

Objective: Prediction of motor function after intracerebral hemorrhage (ICH) often poses a diagnostic challenge. This study was performed to investigate whether intraoperative monitoring of motor-evoked potentials (MEPs) could predict postoperative motor function recovery.

Methods: We reviewed 16 consecutive patients undergoing evacuation of supratentorial ICH with hemiplegia between June 2011 and October 2014. Patients were categorized according to the results of MEPs before and after evacuation of hematoma. The correlation between detection of MEPs and prognosis of motor function was analyzed.

Results: In 10 of 16 cases (62%), stable MEPs were detected before and after evacuation of hematoma, and postoperative motor function was improved in all cases, including 3 cases with severe preoperative motor impairment on manual muscle test (1-2). In 3 cases (19%) in which MEPs were not detected throughout the procedure, motor function was not improved. In the other 3 cases (19%), MEPs were not measured before evacuation of ICH but were detected after evacuation despite poor prognosis of motor function. The results of postevacuation MEPs were considered false-negative results. Predictions using pre-evacuation MEP results were completely consistent with prognosis for recovery, whereas MEPs obtained during and after evaluation were useful for monitoring.

Conclusions: Intraoperative MEPs may indicate preservation of pyramidal tracts, and pre-evacuation MEPs can predict motor function outcome after ICH surgery.
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http://dx.doi.org/10.1016/j.wneu.2016.03.058DOI Listing
June 2016

Intraoperative Transcranial Motor-Evoked Potentials Predict Motor Function Outcome in Intracerebral Hemorrhage Surgery.

World Neurosurg 2016 Jun 26;90:518-523. Epub 2016 Mar 26.

Department of Neurosurgery, Suisyoukai Murata Hospital, Osaka City, Osaka, Japan.

Objective: Prediction of motor function after intracerebral hemorrhage (ICH) often poses a diagnostic challenge. This study was performed to investigate whether intraoperative monitoring of motor-evoked potentials (MEPs) could predict postoperative motor function recovery.

Methods: We reviewed 16 consecutive patients undergoing evacuation of supratentorial ICH with hemiplegia between June 2011 and October 2014. Patients were categorized according to the results of MEPs before and after evacuation of hematoma. The correlation between detection of MEPs and prognosis of motor function was analyzed.

Results: In 10 of 16 cases (62%), stable MEPs were detected before and after evacuation of hematoma, and postoperative motor function was improved in all cases, including 3 cases with severe preoperative motor impairment on manual muscle test (1-2). In 3 cases (19%) in which MEPs were not detected throughout the procedure, motor function was not improved. In the other 3 cases (19%), MEPs were not measured before evacuation of ICH but were detected after evacuation despite poor prognosis of motor function. The results of postevacuation MEPs were considered false-negative results. Predictions using pre-evacuation MEP results were completely consistent with prognosis for recovery, whereas MEPs obtained during and after evaluation were useful for monitoring.

Conclusions: Intraoperative MEPs may indicate preservation of pyramidal tracts, and pre-evacuation MEPs can predict motor function outcome after ICH surgery.
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http://dx.doi.org/10.1016/j.wneu.2016.03.058DOI Listing
June 2016

Fournier's gangrene caused by Listeria monocytogenes as the primary organism.

Can J Infect Dis Med Microbiol 2015 Jan-Feb;26(1):44-6

Department of Infectious Diseases, Tokyo Women's Medical University;

A 70-year-old man with a history of tongue cancer presented with Fournier's gangrene caused by Listeria monocytogenes serotype 4b. Surgical debridement revealed undiagnosed rectal adenocarcinoma. The patient did not have an apparent dietary or travel history but reported daily consumption of sashimi (raw fish). Old age and immunodeficiency due to rectal adenocarcinoma may have supported the direct invasion of L monocytogenes from the tumour. The present article describes the first reported case of Fournier's gangrene caused by L monocytogenes. The authors suggest that raw ready-to-eat seafood consumption be recognized as a risk factor for listeriosis, especially in cases of skin and soft tissue infection.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4353270PMC
http://dx.doi.org/10.1155/2015/501386DOI Listing
March 2015

Bacterial translocation in alymphoplasia (aly/aly) mice.

Folia Biol (Krakow) 2014 ;62(1):9-12

Bacterial translocation (BTL) is defined as the passage of viable bacteria from the gastrointestinal tract to the organs. This study was to elucidate the roles of Peyer's patches (PPs) and/or mesenteric lymph nodes (MLNs) in BTL. Alymphoplastic mutant mice and phenotypically normal heterozygous micewere dominantly colonized with streptomycin-resistant Escherichia coli and BTL was examined. In PP- and MLN-competent mice, BTL to MLNs was detected in 100% of mice, but BTL to organs was rare (25%). On the other hand, in PP- and MLN-deficientmice, BTL to organs was detected in 91% of mice. The results clearly indicate that PPs are not the only site for bacterial entry.
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http://dx.doi.org/10.3409/fb62_1.9DOI Listing
May 2014

Food-borne botulism in Japan in March 2012.

Int J Infect Dis 2014 Jul 5;24:20-2. Epub 2014 Apr 5.

Division of Biomedical Food Research, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan. Electronic address:

In March 2012, two patients were transported urgently to the hospital in Tottori Prefecture, Japan, because of symptoms suggestive of botulism. Botulinum neurotoxin type A was detected in the clinical specimens and the food consumed by the two patients (vacuum packed adzuki-batto, a sweet adzuki bean soup containing noodles). We were able to make a prompt diagnosis of food botulism associated with the consumption of adzuki-batto, from which the causative pathogen Clostridium botulinum Ab was cultured.
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http://dx.doi.org/10.1016/j.ijid.2014.01.014DOI Listing
July 2014

Evaluation of the culture method NIHSJ-02 alternative to ISO 10272-1:2006 for the detection of campylobacter jejuni and campylobacter coli in chicken: collaborative study.

J AOAC Int 2013 Sep-Oct;96(5):991-7

National Institute of Health Sciences, Tokyo 158-8501, Japan.

For the surveillance of the prevalence of Campylobacter jejuni and Campylobacter coli in raw chicken products in Japan, a qualitative method, National Institute of Health Sciences Japan (NIHSJ)-02, was developed as an alternative to International Organization for Standardization (ISO) 10272-1:2006. In the NIHSJ-02 culture method, the enrichment step is carried out in a reduced volume of Preston broth at 42 +/- 1 degrees C to reduce cost and space, and to prevent the overgrowth of background bacteria. To evaluate the performance of NIHSJ-02, a collaborative study was conducted, and the results obtained by NIHSJ-02 were compared with those obtained using the reference method, ISO 10272-1:2006. Fifteen laboratories participated; each examined 48 minced chicken samples consisting of test samples uninoculated, inoculated with C. jejuni at a low or high level, and inoculated with C. coli at a low level. The average probabilities of detection by NIHSJ-02 across laboratories were 0.033, 0.222, 0.678, and 0.267 in samples uninoculated, inoculated with C. jejuni at a low and high level, and with C. coli at a low level, respectively. Those by ISO 10272-1:2006 were 0.051, 0.128, 0.551, and 0.090. Significantly higher probabilities of detection were determined by NIHSJ-02 compared to ISO 10272-1:2006, except for uninoculated samples. On the other hand, significantly lower frequency of occurrence of background bacteria was observed by NIHSJ-02 (43.1%) compared with ISO 10272-1:2006 (92.6%). NIHSJ-02 showed better performance than ISO 10272-1:2006 with regard to the selective detection of C. jejuni and C. coli in chicken.
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http://dx.doi.org/10.5740/jaoacint.13-060DOI Listing
January 2014

Clinical use of (11)C-methionine and (18)F-FDG-PET for germinoma in central nervous system.

Ann Nucl Med 2014 Feb 24;28(2):94-102. Epub 2013 Nov 24.

Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Shouwa-ku, Nagoya, 466-8550, Japan,

Objective: The purpose of this study was to examine the (11)C-methionine (MET) and (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) findings of central nervous system (CNS) germinoma and the diagnostic utility of these findings.

Methods: We retrospectively evaluated the cases of 10 patients who were diagnosed with CNS germinoma according to their histopathological or clinical findings. All the patients underwent pretreatment MET and/or FDG-PET scans, and the resultant images were assessed qualitatively and quantitatively. In the qualitative assessments, we used 3- and 5-grade visual scoring systems for the MET- and FDG-PET images, respectively. In the quantitative assessments, the maximal standardized uptake value (SUVmax) and the ratio of the SUVmax of the tumor (T) divided by the mean SUV for the normal white or gray matter [T/N (WM), T/N (GM)], was calculated.

Results: The mean and SD values of SUVmax, T/N (WM), and T/N (GM) were 1.9 ± 1.4, 2.5 ± 1.3, and 1.7 ± 0.9 on MET-PET and 5.8 ± 2.2, 1.6 ± 0.5, and 0.8 ± 0.2 on FDG-PET, respectively. On MET-PET, only one lesion was not detected. On the other hand, on FDG-PET all of the lesions exhibited uptake values that were intermediate between those of the normal white matter and gray matter.

Conclusion: In terms of its tumor-contouring ability, MET is a good tracer for diagnosing CNS germinomas; therefore, MET-PET is considered to be useful for planning biopsies or surgery. Although FDG-PET is capable of detecting CNS germinomas, it produced insufficient image contrast in the present study. Further studies are needed before FDG-PET can be used in clinical examinations of CNS germinoma.
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http://dx.doi.org/10.1007/s12149-013-0787-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3926980PMC
February 2014

Comparison of liquid crystal display monitors calibrated with gray-scale standard display function and with γ 2.2 and iPad: observer performance in detection of cerebral infarction on brain CT.

AJR Am J Roentgenol 2013 Jun;200(6):1304-9

Department of Radiological Sciences, Nagoya University Graduate School of Medicine, 1-20 Daikominami 1 chome, Higashi-ku, Nagoya, Aichi 461-8673, Japan.

Objective: The purpose of the study was to compare observer performance in the detection of cerebral infarction on a brain CT using medical-grade liquid crystal display (LCD) monitors calibrated with the gray-scale standard display function and with γ 2.2 and using an iPad with a simulated screen setting.

Materials And Methods: We amassed 97 sample sets, from 47 patients with proven cerebral infarction and 50 healthy control subjects. Nine radiologists independently assessed brain CT on a gray-scale standard display function LCD, a γ 2.2 LCD, and an iPad in random order over 4-week intervals. Receiver operating characteristic (ROC) analysis was performed by using the continuous scale, and the area under the ROC curve (A(z)) was calculated for each monitor.

Results: The A(z) values for gray-scale standard display function LCD, γ 2.2 LCD, and iPad were 0.875, 0.884, and 0.839, respectively. The difference among the three monitors was very small. There was no significant difference between gray-scale standard display function LCD and γ 2.2 LCD. However, the A(z) value was statistically significantly smaller for the iPad than the γ 2.2 LCD (p < 0.05).

Conclusion: Observer performance for detecting cerebral infarction on the LCD with γ 2.2 calibration was found to be similar to the LCD with gray-scale standard display function calibration. Although observer performance using the iPad was poorer than that using the other LCDs, the difference was small. Therefore, the iPad could not substitute for other LCD monitors. However, owing to the promising potential advantages of tablet PCs, such as portability, further examination is needed into the clinical use of tablet PCs.
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http://dx.doi.org/10.2214/AJR.12.9096DOI Listing
June 2013

Growth of Listeria monocytogenes in refrigerated ready-to-eat foods in Japan.

Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2013 22;30(8):1446-9. Epub 2013 May 22.

Division of Biomedical Food Research, National Institute of Health Sciences, Tokyo, Japan.

The ability of L. monocytogenes to grow in a series of Japanese ready-to-eat (RTE) foods, including boiled baby sardine and Japanese pickle, was tested at two different refrigeration temperatures. In RTE foods in which L. monocytogenes can grow, growth was significantly higher at 10°C than that at 4°C during their shelf lives and growth patterns varied extensively among the different types of foods. However, growth did not occur at 4°C within the shelf life of certain RTE foods, such as broiled squid. The patterns of growth were varied extensively with different sample types. These results suggest that some types of traditional Japanese RTE foods stored at 10°C may be potential sources of listeriosis. To reduce the risk of food-borne listeriosis, studies to determine the contamination levels in RTE foods and the effects of storage temperature on their shelf lives are needed.
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http://dx.doi.org/10.1080/19440049.2012.762604DOI Listing
March 2014

[Basic research for the control of Campylobacter food poisoning].

Nihon Rinsho 2012 Aug;70(8):1298-303

National Institute of Health Sciences.

Appropriate handling and controlled temperature prevent cross-contamination and proliferation of contaminants in foods, thereby reducing the incidences of food-borne gastroenteritis in Japan. However, the incidence of Campylobacter jejuni/coli infection did not markedly decrease and has become one of the major causes of food-borne diseases. C. jejuni and C. coli are widespread in warm-blooded domestic animals; therefore, food products may easily become contaminated during processing. C. jejuni and C. coli do not proliferate in foods, nor resistant to freezing, drying and oxidative stresses, and the number is greatly reduced under such conditions. These properties should be considered for risk management of Campylobacter in food processing and manufacturing.
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August 2012

Differentiation of newly diagnosed glioblastoma multiforme and intracranial diffuse large B-cell Lymphoma using (11)C-methionine and (18)F-FDG PET.

Clin Nucl Med 2012 Sep;37(9):843-9

Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai cho, Shouwa ku, Nagoya, 466-8550, Japan.

Purpose: The aim of our study was to examine the usefulness of PET with C-methionine (MET) and F-fluorodeoxyglucose (FDG) in the differentiation of glioblastoma multiforme (GBM) and intracranial diffuse large B-cell lymphoma (DLBCL).

Materials And Methods: We evaluated 22 patients retrospectively with an enhancing brain tumor on MRI, including 15 GBM and 7 DLBCL, which was confirmed by histopathology. Dynamic PET scans with MET and FDG were performed for preoperative differential diagnosis. We assessed the images qualitatively and quantitatively. In quantitative assessment, the SUVmax was used on FDG PET and both late and early phases on MET PET. In addition, the ratio of SUVmax in the late and early phases on MET-PET was evaluated (ΔSUVmax).

Results: SUVmax on FDG PET of DLBCL was significantly higher than that of GBM. Setting an SUVmax of 12.0 as the cutoff for differentiating DLBCL from GBM, 1 GBM and 1 DLBCL were found to be false-positive and false-negative, respectively.SUVmax in the late and early phases of MET-PET was not significantly different between DLBCL and GBM; however, we also found significant differences in ΔSUVmax on MET-PET. Using ΔSUVmax 1.17 as the cutoff, we could differentiate DLBCL from GBM completely. In the present study, ΔSUVmax on MET-PET was slightly superior to SUVmax on FDG PET.

Conclusions: Both SUVmax on FDG PET and ΔSUVmax on MET-PET were considered to be good diagnostic tests when encountering difficulties in this differential diagnosis.
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http://dx.doi.org/10.1097/RLU.0b013e318262af48DOI Listing
September 2012

Sequence of busulfan-induced neural progenitor cell damage in the fetal rat brain.

Exp Toxicol Pathol 2013 Jul 10;65(5):523-30. Epub 2012 Apr 10.

Gotemba Laboratories, Biology and Zoology Research Center Inc., 1284, Kamado, Gotemba, Shizuoka 412-0039, Japan.

The sequence of neural progenitor cell (NPC) damage induced in fetal rat brain by transplacental exposure to busulfan, an antineoplastic bifunctional-alkylating agent, on gestational day 13 was examined by immunohistochemical and real-time RT-PCR analyses. Following busulfan treatment, pyknotic NPCs first appeared in the medial layer and then extended to the dorsal layer of the ventricular zone (VZ) of the telencephalon. Pyknotic NPCs that were immunohistochemically positive for cleaved caspase-3, i.e. apoptotic NPCs, began to increase at 24 h after treatment, peaked at 48 h, and returned to the control levels at 96 h. On the other hand, the index (%) of phospho-histone H3-positive NPCs, i.e. mitotic NPCs, and that of BrdU-positive NPCs, i.e. S-phase cells, decreased in accordance with the increase in the index of apoptotic NPCs. Prior to the peak time of apoptotic NPCs, the indices of p53- and p21-positive NPCs peaked at 36 h. In addition, the expression levels of p21 and Puma (p53-target genes) mRNAs were elevated in real-time RT-PCR analysis. These findings indicated that busulfan not only induced apoptosis through the p53-mediated intrinsic pathway but also inhibited cell proliferation in NPCs, resulting in a reduction of the width of the telencephalon. On the other hand, in spite of up-regulation of p21 expression, the expression of cyclin D1, part of the cell cycle machinery of the G1/S transition, and the expression levels of Cdc20 and cyclin B1 which are involved in G2/M transition, showed no changes, giving no possible information of busulfan-induced cell cycle arrest in NPCs.
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http://dx.doi.org/10.1016/j.etp.2012.03.001DOI Listing
July 2013

Intrahost passage alters SigB-dependent acid resistance and host cell-associated kinetics of Listeria monocytogenes.

Infect Genet Evol 2012 Jan 24;12(1):94-101. Epub 2011 Oct 24.

Division of Biomedical Food Research, National Institute of Health Sciences, Kamiyoga 1-18-1, Setagaya-ku, Tokyo 158-8501, Japan.

Listeria monocytogenes is a foodborne pathogen that causes gastroenteritis, maternofetal infections and meningoencephalitis in humans. Here we report that an intrahost genome mutation alters bacterial acid resistance and the abilities for replication/invasion in tissue cell culture. Among the L. monocytogenes isolates from the recent outbreak in Japan, we found that one food strain, 668, exhibited the greatest acid resistance, whereas one human clinical strain, 690, sharing identical pulsed-field gel electrophoresis (PFGE) and ribotyping patterns, exhibited an acid-sensitive phenotype. Passage of the 668 food strain through the mouse intestine increased its acid sensitivity without altering the macrogenotypes, indicating intrahost alteration of the bacterial acid-resistant phenotype. Genetic and proteomic analyses revealed a link between acid resistance and SigB (RNA polymerase SigmaB subunit) activity. Compared with the strain 668, the clinical and 4 of 5 mice-passaged strains showed a mutation in the rsbW locus, whose product controls the regulation of SigB activity. Corresponding to the SigB activity, the host-passaged strains had reduced abilities to survive inside macrophages and to invade Caco-2 cells, compared with the food strain 668. Overall, we have demonstrated the first example of a host environment promoting the alteration of SigB-dependent acid resistance and host cell-associated actions of L. monocytogenes. Our study provides new insight into the potential role of intrahost environment in the process of bacterial evolution.
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http://dx.doi.org/10.1016/j.meegid.2011.10.014DOI Listing
January 2012

The occurrence of Listeria monocytogenes in imported ready-to-eat foods in Japan.

J Vet Med Sci 2012 Mar 31;74(3):373-5. Epub 2011 Oct 31.

Division of Biomedical Food Research, National Institute of Health Sciences, Tokyo 158–8501, Japan.

Quantitative analyses of Listeria monocytogenes in imported ready-to-eat (RTE) foods sold at retail stores in Japan were performed. Of the 77 non-cooked meat products, 6 samples (7.8%) tested positive. The levels of contamination of 4 of the samples were below 100 colony-forming units (CFU)/g, which is the microbiological criterion for L. monocytogenes in RTE foods as determined by Codex. However, Listeria cells at levels of 100 and 400 CFU/g were detected in a salami sample and a raw ham sample, respectively. All of the 70 cheese samples and the 3 samples made from raw ham and cheese showed negative test results. These results suggest that imported RTE foods are potential sources of the causative agent of listeriosis.
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http://dx.doi.org/10.1292/jvms.11-0262DOI Listing
March 2012

Antimicrobial susceptibilities of Listeria monocytogenes isolated in Japan.

J Vet Med Sci 2011 Dec 12;73(12):1681-4. Epub 2011 Aug 12.

Division of Biomedical Food Research, National Institute of Health Sciences, Tokyo 158–8501, Japan.

The antimicrobial susceptibility of 201 Listeria monocytogenes isolates from foods, environments, animals and human patients in Japan was determined. All isolates were susceptible to ampicillin, the first choice of drug for listeriosis treatment, chloramphenicol, dihydrostreptomycin, erythromycin, enrofloxacin, gentamicin, kanamycin, lincomycin, nosiheptide, salinomycin, vancomycin, and virginiamycin. A human strain was resistant to oxytetracycline. The Minimum Inhibitory Concentration (MIC) for 50% of the strains and the MIC for 90% of the strains were comparable in all the isolates. This is the first investigation to compare antibiotic resistances between isolates from foods and isolates from human patients in Japan. The result showed that most of the isolates were susceptible to antibiotics used in this study.
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http://dx.doi.org/10.1292/jvms.11-0051DOI Listing
December 2011

Structure-activity relationship of anthelmintic cyclooctadepsipeptides.

Biosci Biotechnol Biochem 2011 7;75(7):1354-63. Epub 2011 Jul 7.

Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Yokohama, kanagawa, Japan.

The relationship between cyclooctadepsipeptides and their anthelmintic efficacy was examined by converting the natural products, PF1022A, PF1022E and PF1022H. Some analogues substituted at the para position of the phenyllactate moiety showed higher or equivalent activity against the parasitic nematode, Ascaridia galli in chicken when compared with the parent compounds. It is suggested that lipophilicity and the polar surface area, in addition to structural requirements of the derivatives, influenced the anthelmintic efficacy in vivo.
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http://dx.doi.org/10.1271/bbb.110129DOI Listing
November 2011

Ruptured internal carotid artery bifurcation aneurysm presenting with only intracerebral hemorrhage without subarachnoid hemorrhage--case report.

Neurol Med Chir (Tokyo) 2011 ;51(2):117-9

Department of Neurosurgery, Osaka City University Graduate School of Medicine, Abeno-ku, Osaka, Japan.

A 55-year-old man presented with intracerebral hemorrhage (ICH) without subarachnoid hemorrhage (SAH) manifesting as acute onset of consciousness disturbance and right hemiparesis. Computed tomography showed ICH mainly localized in the left putamen, but no evidence of SAH. Magnetic resonance angiography demonstrated a cerebral aneurysm originating from the bifurcation of the left internal carotid artery, which was considered to be responsible for the ICH. The patient underwent emergent intravascular surgery for coil embolization of the aneurysm, and his neurological symptoms gradually recovered with rehabilitation after surgery. Although ICH without SAH is a rare presentation of cerebral aneurysm, ruptured cerebral aneurysm should be considered as a potential cause of ICH. The localization and extent of ICH may be suggestive of latent cerebral aneurysm in such cases.
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http://dx.doi.org/10.2176/nmc.51.117DOI Listing
July 2013

Central neurocytoma presenting with massive hemorrhage leading to coma--case report.

Neurol Med Chir (Tokyo) 2010 ;50(2):139-43

Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka.

A 21-year-old man presented with a hemorrhagic central neurocytoma manifesting as acute onset of disturbance of consciousness and right hemiparesis. Computed tomography (CT) demonstrated a tumor in the left lateral ventricle during the course of evaluation for mental alteration 12 days before onset, but the tumor was left untreated because the patient refused to visit a neurosurgical institution. CT on admission revealed a large mass lesion located in the body of the lateral ventricle associated with massive intratumoral and intraventricular hemorrhage. He underwent emergent surgery for evacuation of the tumor with hematoma, and his neurological symptoms gradually recovered after surgery. The present case highlights the possibility of rapid deterioration of symptoms by massive hemorrhage from central neurocytoma. Surgical intervention should thoroughly be considered, if intratumoral hemorrhage is present, as hemorrhage from the central neurocytoma may lead to serious neurological complications.
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http://dx.doi.org/10.2176/nmc.50.139DOI Listing
June 2010

[Study on the effects of HTST pasteurization temperatures on Mycobacterium avium subsp. paratuberculosis in an industrial fluid milk-processing system].

Kokuritsu Iyakuhin Shokuhin Eisei Kenkyusho Hokoku 2010 (128):81-4

Johne disease is ruminant chronic granulomatous enteritis caused by Mycobacterium avium subsp. paratuberculosis (MAP). The domestic animals infected with this pathogen present severe weight loss due to chronic diarrhea and a reduction in lactation yield. These result in enormous economic loss since the affected animals are subsequently subject to artificial selections and disinfection of the environment are absolutely necessary. Furthermore, MAP has been suspected to have pathological relationship to Crohn's disease, human chronic granulomatous enteritis. The bacterium grows slower on solid culture and its colony becomes visible after two months of culture. In Japan, there has been almost no investigation on pasteurization temperature of commercial milk using MAP. It comes from the fact that the growth rate of MAP is very slow and that MAP is a related species to Mycobacterium tuberculosis, which pasteurization condition has been well defined. The studies on the pasteurization conditions of commercial milk have been mainly targeted to reduce the risk of infection to Coxiella and Mycobacterium tuberculosis. However, there has been a concern about the possibility that MAP is remained in pasteurized milk because MAPs form an aggregate and the bacterium at its center may not receive enough heat to get pasteurized. From these reasons, the present study aims to investigate validity of the current pasteurization conditions of commercial milk by implementing experimental pasteurization at various pasteurization temperatures using milk experimentally infected with MAP, and to clarify if MAP is eliminated at these temperatures in order to achieve smooth enforcement of the current ministry order. We conducted plant pasteurization experiment at four pasteurization conditions (high temperature, short time (HTST); 82, 77, 72 degrees C for 15 seconds and low temperature, long time (LTLT); 63 degrees C for 30 minutes) using two MAP strains, ATCC19698 and OKY-20. In conclusion, there appeared no colony of the two MAP strains formed from the milk pasteurized at the four pasteurization conditions examined.
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May 2011

Gene expression profile of Vibrio cholerae in the cold stress-induced viable but non-culturable state.

Environ Microbiol 2007 Apr;9(4):869-79

Division of Biomedical Food Research, National Institute of Health Sciences, Kamiyoga 1-18-1, Tokyo 158-8501, Japan.

Vibrio cholerae is an aetiological agent of cholera that inhabits marine and estuarine environments. It can survive harsh environments by entering the viable but non-culturable (VBNC) state, but the related changes in gene expression have not been described. Here, we experimentally induced the VBNC state in V. cholerae O1, by incubation in artificial seawater at 4 degrees C. Bacterial cells that were incubated for 70 days retained their membrane integrity and were pathogenic, colonizing the gut of iron-dextran-treated mice, even though they formed no colonies on tryptic soy agar (TSA) or TSA amended with pyruvate. We therefore used this stage of cells as the VBNC bacteria. We compared the global transcription pattern of the VBNC cells with that of stationary-phase cells grown in rich medium. A total of 100 genes were induced by more than fivefold in the VBNC state, and the modulated genes were mostly those responsible for cellular processes. Furthermore, real-time RT-PCR analysis verified the changes in the expression levels, showing that the VC0230 [iron(III) ABC transporter], VC1212 (polB), VC2132 (fliG) and VC2187 (flaC) mRNAs were increased in the non-culturable state. Thus, these genes may be suitable markers for the detection of VBNC V. cholerae. To our knowledge, this is the first report of a comprehensive transcriptome analysis of V. cholerae in the VBNC state. The significance of this gene expression profile compared with those of in vivo isolates and non-stressed bacteria (culturable in vitro) is its potential to provide information about the public health risk from dormant bacteria.
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http://dx.doi.org/10.1111/j.1462-2920.2006.01206.xDOI Listing
April 2007

The sigma factor RpoN (sigma54) is involved in osmotolerance in Listeria monocytogenes.

FEMS Microbiol Lett 2006 Oct;263(1):54-60

Division of Biomedical Food Research, National Instutute of Health Sciences, Tokyo 158-8501, Japan.

Listeria monocytogenes is able to grow under conditions of high osmolarity. We constructed a deletion mutant of rpoN, encoding the alternative sigma factor RpoN, and analyzed its response to osmotic stress. In a minimal medium with 4% NaCl and 1 mM betaine, the mutant showed a similar growth to that of the parental strain, EGD. In the same medium with 4% NaCl and 1 M carnitine, the growth rate of the mutant was greatly reduced, when the optical density at 600 nm (OD600) at the starting point of growth, was 0.15. However, when growth of the culture was started at an OD600 of 0.025, the growth of the mutant was similar to that of EGD. The mutant's expression of two betaine transporter genes, betL and gbuB, and the carnitine transporter gene opuCA, was osmotically induced at a level similar to EGD, and its rate of carnitine uptake was similar to that of EGD. These results suggest that the growth defect from the rpoN mutant is caused not by the transcriptional regulation of opuCA or by a decrease in carnitine uptake, but possibly by larger amounts of carnitine being needed for growth of the mutant in minimal medium when NaCl is present.
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http://dx.doi.org/10.1111/j.1574-6968.2006.00405.xDOI Listing
October 2006

Overview of Listeria monocytogenes contamination in Japan.

Int J Food Microbiol 2004 Jun;93(2):131-40

Division of Biomedical Food Research, National Institute of Health Sciences, 1-18-1, Kamiyoga, Setagaya, 158-8501, Tokyo, Japan.

Listeriosis is a relatively rare foodborne illness but can be life threatening with high fatality rates. In Japan, the incidence of listeriosis has been very low for the past 40 years compared with that of Western Europe and North America. We hypothesized that less Listeria monocytogenes contamination in Japanese foods would be related to the lower incidence in Japan. For this purpose, we collected data of Japanese foods contaminated with L. monocytogenes, mainly from Japanese-written reports, and reviewed them. From this review, we found that the proportion of L. monocytogenes, Listeria spp. isolation from foods in Japan is similar to those reported from other countries and that other factors might be responsible for the lower occurrence of listeriosis.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2003.11.014DOI Listing
June 2004
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