Publications by authors named "Masaharu Yamamoto"

A chiral reaction field with thermally invertible helical sense enables control of the helicity of the reaction product, which is a central challenge in asymmetric synthesis that has yet to be overcome. A novel chiral compound comprising two types of chiral moieties with opposite helicities and temperature dependences is synthesized; this compound is added as a chiral dopant to a mixture of nematic liquid crystals to prepare a chiral nematic liquid crystal (N*-LC). The N*-LC containing the chiral dopant exhibits thermally invertible helicity to yield left- and right-handed helical senses at low and high temperatures, respectively.

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The objective of this study is to design primary drying conditions in a production lyophilizer based on a pilot lyophilizer. Although the shelf temperature and the chamber pressure need to be designed to maintain the sublimation interface temperature of the formulation below the collapse temperature, it is difficult to utilize a production lyophilizer to optimize cycle parameters for manufacturing. In this report, we assumed that the water vapor transfer resistance (R) in the pilot lyophilizer can be used in the commercial lyophilizer without any correction, under the condition where both lyophilizers were operated in the high efficiency particulate air (HEPA)-filtrated airflow condition.

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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.

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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.

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Our previous study detected aflatoxins in red chili peppers from Chile, Bolivia, and Peru, each of which have a high incidence of gallbladder cancer (GBC). Since the aflatoxin B1 concentration was not so high in these peppers, it is important to clarify the presence of other mycotoxins. Here we attempted to determine any associations between the concentrations of aflatoxins and ochratoxin A (OTA) in red chili peppers, and the corresponding GBC incidences.

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Although genetic characteristics are considered to be a factor influencing the geographic variation in the prevalence of gallbladder cancer (GBC), they have not been well studied in Bolivia, which has a high prevalence rate of GBC. The purpose of this study was to examine the frequency of TP53 and K-ras mutations in Bolivian patients with GBC and to compare them with our previous data obtained in other high-GBC-prevalence countries, namely Japan, Chile, and Hungary. DNA was extracted from cancer sites in paraffin-embedded tissue from 36 patients using a microdissection technique.

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Chilean red chili peppers contaminated with aflatoxins were reported in a previous study. If the development of gallbladder cancer (GBC) in Chile is associated with a high level of consumption of aflatoxin-contaminated red chili peppers, such peppers from other countries having a high GBC incidence rate may also be contaminated with aflatoxins. We aimed to determine whether this might be the case for red chili peppers from Bolivia and Peru.

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High consumption of red chili pepper has been shown to be a risk factor for gallbladder cancer (GBC) in Chilean women with gallstones, and included mutagens may be important in this context. We aimed to investigate the mutagenicity and mutagens in Chilean red chili pepper in the Ames test using Salmonella typhimurium strains TA98, TA1537, TA100, and TA1535 with and without metabolic activation (S9 mix). Pure capsaicin was tested for mutagenicity using strain TA98.

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Background And Aims: High consumption of red chili pepper has been shown to be a risk factor for gallbladder cancer (GBC) in Chilean women. However, genetic factors in addition to this and other environmental factors may also be associated with an increased risk of GBC. We aimed to examine the associations of cytochrome P450 1A1 (CYP1A1), glutathione S-transferase class mu (GSTM1), and tumor protein p53 (TP53) polymorphisms with the risk of GBC in Chilean women.

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Unsaturated free fatty acids (FFAs), such as palmitoleic, oleic, linoleic, linolenic and arachidonic acids, have inhibitory actions on mutagenesis. These FFAs in bile may play a role in preventing cholecystopathy and their levels may be influenced by diet. However, the effects of dietary intake on biliary FFAs levels are not known.

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Our previous study indicated an association of chili pepper consumption with gallbladder cancer (GBC) in the presence of gallstones (GS) in Chile. We investigated whether or not a similar association was present in Hungary, where mortality from GBC is high and chili peppers are frequently consumed. In a case-control study, we compared 41 female GBC patients with GS and 30 gender and GS-matched hospital controls.

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Aim: To determine the effects of genetic variants associated with gallstone formation and capsaicin (a pungent component of chili pepper) metabolism on the risk of gallbladder cancer (GBC).

Methods: A total of 57 patients with GBC, 119 patients with gallstones, and 70 controls were enrolled in this study. DNA was extracted from their blood or paraffin block sample using standard commercial kits.

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Objective: Very few epidemiologic studies on bone fracture have been conducted in schools for handicapped children (Yogo schools). The aim of this study was to clarify the frequency and risk factors of bone fracture in physically disabled children in Japan.

Methods: We used a cross-sectional design to examine 525 physically disabled children in 38 Yogo schools in the Hokuriku-Koshinetsu District of Japan.

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Objectives: The 5-year survival rate for pancreatic cancer is known to be lower than that for cancer at any other site in the body, and the proportion of pancreatic cancer deaths among all cancer deaths has been increasing in Japan. The aim of this study was to investigate pancreatic cancer mortality in the light of temporal and geographical trends in the 47 prefectures of the country between 1968 and 2002.

Methods: To survey the geographical aspects of pancreatic cancer mortality, we mapped the direct age-adjusted mortality rates of persons aged 40 years and older by sex in seven 5-year periods (1968-1972 to 1998-2002).

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Objective: Clarifying the characteristics of attention-deficit/hyperactivity disorder (ADHD) symptoms in childhood is important for the prevention and management of this disorder. The purpose of this study was to determine the prevalence of ADHD symptoms in Japanese preschool children based on evaluations performed by parents or teachers.

Methods: A questionnaire survey was performed to evaluate the estimated prevalence of ADHD symptoms in preschool children in Niigata City, Japan.

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Objective: Low Ca intake is common among Japanese women, but its effect on bone metabolism has not been fully elucidated. The aim of the present study was to determine the relationship between Ca intake and serum markers of bone turnover in postmenopausal Japanese women.

Design: A cross-sectional study.

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Infants' rapid (catch-up) weight gain is associated with later obesity and chronic adult diseases. The aim of this study was to determine maternal and environmental factors related to rapid weight gain at one month and 18 months after full-term birth in Japan. Subjects were 1,524 infants and their mothers who visited the 18-month check-up in Niigata City between October 1, 2007 and September 30, 2008.

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Little is known concerning renal or urological risk factors for osteoporosis. The aim of this study was to explore an association between urinalysis and bone mineral density (BMD) in 4,835 Japanese adults. Participants were 4,835 individuals (female 3,683; male 1,152) aged 50 years and over who received a health check-up between January 1995 and March 2006 in Japan.

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Background: In Japan, the current standard waist circumference cutoff value for persons with multiple cardiovascular risk factors remains controversial. In this study we aimed to analyze the health-check examination data from a large Japanese population and propose a revised waist circumference cutoff value.

Methods: Subjects of this study were 12,725 adults who underwent a health-check by thorough medical examination between April 2006 and March 2007.

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The purpose of this study was to determine a possible association between magnesium intake and bone mass in young adult women. Subjects consisted of 106 female university students aged 19-25 years. Calcium and magnesium intakes were evaluated using the duplicate sampling method on three weekdays.

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The number of female doctors in Japan has been increasing, but the relationship between their work environment and their mental health is not clear. This study aimed to determine factors in the work environment influencing mental health status among female doctors. We mailed an anonymous survey questionnaire to 587 female doctors, and 367 (62.

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Aim: To disclose geographic differences in genetic changes involved in gallbladder carcinogenesis between two distinct high-incidence areas of Japan and Hungary.

Methods: We examined 42 cases of gallbladder carcinoma: 22 Japanese and 20 Hungarian cases. p53 mutations at exons 5 to 8 and K-ras mutations at codon 12 were tested by direct sequencing.

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Little has been understood about vitamin D status in relation to bone health in Asian women. The purpose of this study was to identify how the serum 25-hydroxyvitamin D (25[OH]D) concentration is associated with bone mass and bone metabolism. This cross-sectional, community-based epidemiologic study was conducted among 600 ambulatory postmenopausal women.

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