Biomedical subjects

Kunihiko Takahashi

Publications and source records attributed to Kunihiko Takahashi.

9 recordsLinked to original sources

PubMed2006

An extended power of cluster detection tests.

Several tests have been proposed to detect spatial disease clustering without prior information on their locations. In order to compare the performance of these tests, most authors employ the usual power, i.e. the rejection probability of the null hypothesis of no clustering due to various reasons. However, the usual power is not always appropriate for evaluating the cluster detection tests since their purpose is to both reject the null hypothesis and identify the cluster areas accurately. In this paper, we propose an extended power of the cluster detection tests, which includes the usual power as a special case. Further, we define the profile of the extended power, which can be expected to play an important role in the evaluation and comparison of several cluster detection tests. The proposed extended power and its profile are demonstrated by two tests--Kulldorff's circular spatial scan statistic and a flexible spatial scan statistic proposed by Tango and Takahashi.

Cluster Analysis↗

PubMed2006

[Simultaneous determination of pesticide residues in crops by liquid chromatography with tandem mass spectrometry].

A simultaneous method using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was developed for the determination of pesticide residues in crops. Mass spectral acquisition was performed in the positive mode by applying multiple reaction monitoring. In LC separation, an Atlantis dC18 Column was used with acetic acid-ammonium acetate-acetonitrile as the mobile phase. Pesticide residues in crops were extracted with acetone, and cleaned up by liquid-liquid separation with saturated salt solution and hexane, followed by an ENVI-Carb cartridge. The quantification limits of compounds in crops were below 5 ng/g. Eighty compounds were obtained with recoveries ranging from 60 to 130% at the level of 50 ng/g with RSD (%) of less than 15%. Fifty crop samples were analyzed by the developed method. Seven pesticide residues were detected in nine crops.

Chromatography, Liquid↗

PubMed2005

A flexibly shaped spatial scan statistic for detecting clusters.

BACKGROUND: The spatial scan statistic proposed by Kulldorff has been applied to a wide variety of epidemiological studies for cluster detection. This scan statistic, however, uses a circular window to define the potential cluster areas and thus has difficulty in correctly detecting actual noncircular clusters. A recent proposal by Duczmal and Assunção for detecting noncircular clusters is shown to detect a cluster of very irregular shape that is much larger than the true cluster in our experiences. METHODS: We propose a flexibly shaped spatial scan statistic that can detect irregular shaped clusters within relatively small neighborhoods of each region. The performance of the proposed spatial scan statistic is compared to that of Kulldorff's circular spatial scan statistic with Monte Carlo simulation by considering several circular and noncircular hot-spot cluster models. For comparison, we also propose a new bivariate power distribution classified by the number of regions detected as the most likely cluster and the number of hot-spot regions included in the most likely cluster. RESULTS: The circular spatial scan statistics shows a high level of accuracy in detecting circular clusters exactly. The proposed spatial scan statistic is shown to have good usual powers plus the ability to detect the noncircular hot-spot clusters more accurately than the circular one. CONCLUSION: The proposed spatial scan statistic is shown to work well for small to moderate cluster size, up to say 30. For larger cluster sizes, the method is not practically feasible and a more efficient algorithm is needed.

Journal Article↗

PubMed2005

A novel mutation in the PTPN11 gene in a patient with Noonan syndrome and rapidly progressive hypertrophic cardiomyopathy.

UNLABELLED: A male infant with clinical features of Noonan syndrome and rapidly progressive hypertrophic cardiomyopathy is reported. He manifested severe heart failure and failure to thrive. Administration of propranolol and cibenzoline improved ventricular outflow tract obstruction, leading to catch-up growth. Genetic analysis of the patient revealed a novel missense mutation in the PTPN11 gene. CONCLUSION: This is the first description of a patient with a Gln510Glu mutation in the protein-tyrosine phosphatase, non-receptor type 11 gene. This specific mutation may be associated with a rapidly progressive hypertrophic cardiomyopathy.

Cardiomyopathy, Hypertrophic↗

PubMed2005

[Study on positive control for GM papaya (55-1) detection method by GUS (beta-glucuronidase) assay].

A suitable positive control was investigated for histochemical assay (GUS-examining method) to detect genetically modified (GM) papaya (55-1), currently undergoing a safety assessment in Japan. Six different kinds of test papers were soaked with beta-glucuronidase solution and examined for GUS activity. The test papers made of nylon and glass fiber turned blue, and were stable for fifteen months at -20 degrees C. They are concluded to be useful as positive controls in the GUS-examining method for inspection of GM papaya (55-1).

Carica↗

PubMed2004

New qualitative detection methods of genetically modified potatoes.

In Japan, 8 lines of genetically modified (GM) potato (2 lines of NewLeaf potato; NL, 3 lines of NewLeaf Plus potato; NLP, and 3 lines of NewLeaf Y potato; NLY) have already been authorized as safe for use in foods and feeds. We have developed polymerase chain reaction (PCR) methods for the qualitative detection of the GM potatoes for the screening and the identification of NL, NLP and NLY. The gene encoding uridine diphosphate (UDP)-glucose pyrophosphorylase (UGPase) was used as a taxon specific gene. We designed the primer pair to detect the cryIIIA genes as a screening method for GM potatoes because the gene should be inserted in all 8 lines of the GM potatoes. For identification of NL, NLP and NLY, we further designed three specific primer pairs for the different recombinant DNAs (r-DNA) specifically introduced into NL, NLP, or NLY. In addition, to identify the 3 lines of NLY that have been introduced with the same r-DNA, the three line-specific primer pairs for the border sequence between the r-DNA and genomic DNA of NLY 3 lines were designed. Six lines of GM potato used as the test material were specifically identified using the each primer pair under the same PCR condition. The detection limits of all the GM potatoes should be approximately 0.1%. Furthermore, the specificity and reproducibility of the methods were confirmed in a six-laboratory collaborative study.

Bacillus thuringiensis Toxins↗

PubMed2004

A histochemical method using a substrate of beta-glucuronidase for detection of genetically modified papaya.

A histochemical assay for detecting genetically modified (GM) papaya (derived from Line 55-1) is described. GM papaya, currently undergoing a safety assessment in Japan, was developed using a construct that included a beta-glucuronidase (GUS) reporter gene linked to a virus coat protein (CP) gene. Histochemical assay was used to visualize the blue GUS reaction product from transgenic seed embryos. Twelve embryos per fruit were extracted from the papaya seeds using a surgical knife. The embryos were incubated with the substrate 5-bromo-4-chloro-3-indolyl-beta-D-glucuronide (X-Gluc) in a 96-well microtiter plate for 10-15 hours at 37 degrees C. Seventy-five percent of GM papaya embryos should turn blue theoretically. The histochemical assay results were completely consistent with those from a qualitative polymerase chain reaction (PCR) method developed by this laboratory. Furthermore, the method was validated in a five-laboratory study. The method for detection of GM papaya is rapid and simple, and does not require use of specialized equipment.

Carica↗

PubMed2004

[Health care resources and mortality as assessed by the "empirical Bayes estimate of standardized mortality ratio": results for Fukuoka Prefecture].

BACKGROUND AND OBJECTIVE: The standardized mortality ratio (SMR) is frequently used to compare health status among different populations. However, it may be biased when based upon communities with small population sizes such as towns, cities, and wards. Thus, comparison of SMRs among such small communities is not appropriate. But the "empirical Bayes estimate of standardized mortality ratio" (EBSMR) is, in contrast, a useful index. The objective of the present study was to use the EBSMR to clarify the relationships between health care resources and mortalities in 109 communities in Fukuoka Prefecture. MATERIALS AND METHODS: Data for health care resources (number of physicians, number of general clinics, number of general sickbeds in hospitals, number of emergency hospitals, and proportion of elderly outpatients within their resident' community) and socioeconomic factors (birth rate, inflow or outflow population, aged households, marital status, taxable income per individual under taxes duty, unemployment, primary, secondary, tertiary industrial employment and criminal offense records) were obtained from officially published reports. EBSMRs for all causes, cerebrovascular disease, heart disease, malignant neoplasms, and acute myocardial infarction were calculated from the 1993-1997 vital statistic records. Multiple regression analysis with stepwise variable selection was used to examine the relationships between EBSMRs and the five variables representing health care resources, considering the eleven socioeconomic factors as covariates. Some of the variables were log-transformed to normalize the distribution. RESULTS: Some of the EBSMRs were inversely related to the numbers of physicians per person (acute myocardial infarction in males (P=0.047) and females (P=0.012)), emergency hospitals per person (acute myocardial infarction in females: P=0.001), and general sickbeds per person (all causes in females: P<0.001, cerebrovascular disease in females: P=0.007, heart disease in females: P<0.001, malignant neoplasms in females: P=0.049). In contrast, when the higher the number of clinics per person, the higher the EBSMR in females for all causes (P=0.025), as well as acute myocardial infarction (P=0.006). CONCLUSION: The results suggest that an appropriate distribution of hospital care resources such as physicians, general sickbeds, and emergency hospitals is an important factor related to mortality in a community.

Aged↗

PubMed2002

Protein kinase C activation by iridal type triterpenoids.

Eleven iridal type triterpenoids from Iris tectorum and Belamcanda chinensis were examined for protein kinase C (PKC) activation and binding activity to PKC. Among the tested compounds, nine iridals showed dose-dependent activities, and a mutual relation between the two activities was also observed. 28-Deacetylbelamcandal, which has been found to be a new class 12-O-tetradecanoylphorbol 13-acetate type tumor promoter, showed the most potent activity in both tests. The structural requirements of the iridals inducing these activities were as follows: 1) a hydrophobic side-chain, 2) an E-methylidene aldehyde group at the C-1 position, and 3) a hydroxyl group at the C-26 position.

Dose-Response Relationship, Drug↗