Browsing by Autor "Toshikazu Ikoma"

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CYP1A1, GSTM1, GSTT1 and TP53 Polymorphisms and Risk of Gallbladder Cancer in Bolivians
(West Asia Organization for Cancer Prevention, 2016) Kazuaki Sakai; Ernesto Loza; Guido Villa-Gomez Roig; Ryoko Nozaki; Takao Asai; Toshikazu Ikoma; Yasuo Tsuchiya; Chikako Kiyohara; Masaharu Yamamoto; Kazutoshi Nakamura
The Plurinational State of Bolivia (Bolivia) has a high incidence rate of gallbladder cancer (GBC). However, the genetic and environmental risk factors for GBC development are not well understood. We aimed to assess whether or not cytochrome P450 (CYP1A1), glutathione S-transferase mu 1 (GSTM1), theta 1 (GSTT1) and tumor suppressor protein p53 (TP53) genetic polymorphisms modulate GBC susceptibility in Bolivians. This case-control study covered 32 patients with GBC and 86 healthy subjects. GBC was diagnosed on the basis of histological analysis of tissues at the Instituto de Gastroenterologia Boliviano-Japones (IGBJ); the healthy subjects were members of the staff at the IGBJ. Distributions of the CYP1A1 rs1048943 and TP53 rs1042522 polymorphisms were assayed using PCR-restriction fragment length polymorphism assay. GSTM1 and GSTT1 deletion polymorphisms were detected by a multiplex PCR assay. The frequency of the GSTM1 null genotype was significantly higher in GBC patients than in the healthy subjects (odds ratio [OR], 2.35; 95% confidence interval [CI], 1.03-5.37; age-adjusted OR, 3.53; 95% CI, 1.29-9.66; age- and sex-adjusted OR, 3.40; 95% CI, 1.24-9.34). No significant differences were observed in the frequencies of CYP1A1, GSTT1, or TP53 polymorphisms between the two groups. The GSTM1 null genotype was associated with increased GBC risk in Bolivians. Additional studies with larger control and case populations are warranted to confirm the association between the GSTM1 deletion polymorphism and GBC risk suggested in the present study.
Effect of Mass Stool Examination and Mass Treatment For Decreasing Intestinal Helminth and Protozoan Infection Rates in Bolivian Children: A Cross-Sectional Study
(Public Library of Science, 2016) Takao Asai; Claudia Còrdova Vidal; W Strauss; Toshikazu Ikoma; Kazuo Endoh; Masaharu Yamamoto
Bolivia is one of the countries with a high intestinal helminth and protozoan infection rate. Despite the high prevalence of the parasitic infection, nationwide preventive measures for Bolivian children have not yet been implemented. We evaluated the effect of mass stool examination and treatment as a strategy for decreasing the infection rate. This study was conducted between 2013 and 2015 in children aged 2-18 years. A total of 2,033 stool samples (575 in 2013, 815 in 2014 and 642 in 2015) were collected and examined using the formalin-ether medical sedimentation method. As an anthelminthic medicine, nitazoxanide was given to all infected children within 2 months post-examination, each year. The effect of mass stool examination and treatment was evaluated based on the changes in the overall or individual parasitic infection rates during the study period. The overall parasitic infection rate decreased significantly from 65.2% in 2013 to 43.0% in 2015; a 22.2 percentage point decrease (P<0.001). Protozoan infection accounted for a large portion of the parasitic infections, in the following rates: 62.4% in 2013, 49.3% in 2014, and 41.0% in 2015. The rate of the most common helminth infection, Hymenolepis nana, decreased significantly from 9.0% in 2013 to 6.4% in 2014 to 3.4% in 2015 (P<0.001). Prevalence of the most common pathogenic protozoan infection, Entamoeba histolytica, decreased significantly from 19.0% in 2013 to 3.0% in 2015 (P<0.001). Conversely, the rate of Giardia intestinalis increased significantly from 16.5% in 2013 to 21.2% in 2015 (P<0.01). Mass stool examination and treatment for intestinal helminth and protozoan infections was effective for decreasing the overall parasitic infection rate in the study population, excluding Giardia intestinalis. Further studies on the long-term effect of mass stool examination and treatment for decreasing all intestinal parasitic infection rates in Bolivian children are needed.
Metagenomics of Microbial Communities in Gallbladder Bile from Patients with Gallbladder Cancer or Cholelithiasis
(National Institutes of Health, 2018) Yasuo Tsuchiya; Ernest Loza; Guido Villa‐Gomez; Carlos C Trujillo; Sergio Báez; Takao Asai; Toshikazu Ikoma; Kazuo Endoh; Kazutoshi Nakamura
Salmonella typhi and Helicobacter infections have been shown to increase risk of gallbladder cancer (GBC), but findings have been inconsistent. Other bacterial infections may also be associated with GBC. However, information on microbial pathogens in gallbladder bile of GBC patients is scarce. We aimed to investigate the microbial communities in gallbladder bile of patients with GBC and cholelithiasis (CL). Seven GBC patients and 30 CL patients were enrolled in this study. Genomic DNA was extracted from bile and the V3-V4 region of 16S rRNA was amplified. The sequencing results were compared with the 16S database, and the bacteria were identified by homology searches and phylogenetic analysis. DNA was detected in the bile of three GBC (42.9%; Bolivia, 1; Chile, 2) and four CL patients (13.3%; Bolivia, 1; Chile, 3). Of the 37 patients, 30 (81.1%) were negative and unable to analyze. Salmonella typhi and Helicobacter sp. were not detected in bile from any GBC patients. As the predominant species, Fusobacterium nucleatum, Escherichia coli, and Enetrobacter sp. were detected in bile from GBC patients. Those in bile from CL patients were Escherichia coli, Salmonella sp., and Enerococcus gallinarum. Escherichia coli was detected in bile samples from both GBC and CL patients. Whether the bacteria detected in bile from GBC patients would associated with the development of GBC warrant further investigation.