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Biomedical subjects

Akira Sugiyama

Publications and source records attributed to Akira Sugiyama.

13 recordsLinked to original sources
PubMed2006

Establishment of a high sensitivity plasma assay for human pentraxin3 as a marker for unstable angina pectoris.

OBJECTIVE: Plasma pentraxin 3 (PTX3) levels are increased in patients with acute myocardial infarction, yet its involvement in unstable angina pectoris (UAP) remains unclear. To critically evaluate the role of PTX3 in UAP, a sensitive and precise measurement of PTX3 concentration is needed. METHODS AND RESULTS: We established a high sensitive plasma ELISA assay system for the detection of PTX3 using monoclonal antibodies. The lower limit of detection of our ELISA was 0.1 ng/mL, sensitivity far greater than the current commercially available kit. Plasma samples were obtained from 162 consecutive patients treated for hypertension, hyperlipidemia, diabetes mellitus, or cardiovascular disease at a physician's office. PTX3 was not associated with any known coronary risk factors. Additionally, we collected plasma samples from 252 consecutive subjects admitted to a university hospital for coronary artery assessment by coronary angiography. PTX3 was significantly increased in patients in whom coronary intervention was performed. We further analyzed the plasma level of PTX3 in 52 patients with effort angina (EAP) and 16 patients with UAP. Compared with the control group, PTX3 were significantly higher in the UAP group. CONCLUSIONS: The levels of plasma PTX3 were increased in patients with arterial inflammation, especially UAP. This PTX3 detection system will be useful for the prediction of UAP.

Adult↗
PubMed2005

Gene expression profiling of potential peroxisome proliferator-activated receptor (PPAR) target genes in human hepatoblastoma cell lines inducibly expressing different PPAR isoforms.

BACKGROUND: Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors and commonly play an important role in the regulation of lipid homeostasis. To identify human PPARs-responsive genes, we established tetracycline-regulated human hepatoblastoma cell lines that can be induced to express each human PPAR and investigated the gene expression profiles of these cells. RESULTS: The expression of each introduced PPAR gene was investigated using the various concentrations of doxycycline in the culture media. We found that the expression of each PPAR subtype was tightly controlled by the concentration of doxycycline in these established cell lines. DNA microarray analyses using these cell lines were performed with or without adding each subtype ligand and provided much important information on the PPAR target genes involved in lipid metabolism, transport, storage and other activities. Interestingly, it was noted that while ligand-activated PPARdelta induced target gene expression, unliganded PPARdelta repressed these genes. The real-time RT-PCR was used to verify the altered expression of selected genes by PPARs and we found that these genes were induced to express in the same pattern as detected in the microarray analyses. Furthermore, we analysed the 5'-flanking region of the human adipose differentiation-related protein (adrp) gene that responded to all subtypes of PPARs. From the detailed analyses by reporter assays, the EMSAs, and ChIP assays, we determined the functional PPRE of the human adrp gene. CONCLUSION: The results suggest that these cell lines are important tools used to identify the human PPARs-responsive genes.

Journal Article↗
PubMed2003

Thrombin and phenotypic modulation of the endothelium.

Thrombin signaling in the endothelium is linked to multiple phenotypic changes, including alterations in permeability, vasomotor tone, and leukocyte trafficking. The thrombin signal is transduced, at least in part, at the level of gene transcription. In this review, we focus on the role of thrombin signaling and transcriptional networks in mediating downstream gene expression and endothelial phenotype. In addition, we report the results of DNA microarrays in control and thrombin-treated endothelial cells. We conclude that (1) thrombin induces the upregulation and downregulation of multiple genes in the endothelium, (2) thrombin-mediated gene expression involves a multitude of transcription factors, and (3) future breakthroughs in the field will depend on a better understanding of the spatial and temporal dynamics of these transcriptional networks.

Blood Coagulation↗
PubMed2003

[Poliovirus uptake into and excretion from oysters: a model experiment for elimination of Norwalk-like viruses from oysters].

Outbreaks of gastroenteritis caused by Norwalk-like viruses are often induced by the consumption of raw shellfish such as oysters. Incidences reach a peak during the cold season in Japan, when seawater temperatures fall below 10 degrees C. We investigated oysters' uptake and excretion of viruses, over varying lengths of exposure, monitoring the effects of changes in temperature and flow rate of seawater, and the presence of plankton. The study was performed using a poliovirus and an experimental circulatory system, which was framed on the same principle as a model practically used for the depuration of oysters. Polioviruses present in the seawater were taken rapidly into the midgut gland of oysters. However, virus levels detected in oysters at both 10 degrees C and 20 degrees C were decreased to approximately 1/1,000 to 1/10,000 within 6 hrs after the circulatory seawater was replaced by UV irradiated seawater. These results demonstrate the effectiveness of the circulatory depuration system for the elimination of poliovirus from oysters, and indicate that controlling the temperature and flow rate of the circulatory system could decrease the risk of NLV infection.

Animals↗
PubMed2003

[Efficacy of influenza vaccine for young children in Mie Prefecture in the 1999/2000 prevalent season].

PURPOSE: The purpose of this survey was to investigate the efficacy and safety of influenza HA vaccine for children between 1 and 6 years of age in Mie Prefecture during the 1999/2000 prevalent season. METHODS: We surveyed clinical data for children aged between 1 to 6 who visited five clinics in Mie Prefecture. Dividing them into vaccinated and non-vaccinated groups, we surveyed their basic properties, disease histories and manifestation of symptoms. The survey was performed with the consent of parents who were informed of the purpose. We also surveyed the adverse effects within 48 hours after vaccination. The serum HI titers of the vaccinated children were sampled three times: before the first vaccination and after the first and second vaccinations. The data were analysed with the chi-squared test and a multiple logistic model. RESULTS: The frequency of febrile episodes above 38 degrees C was significantly lower in the vaccinated than the non-vaccinated group. While the relative risk for the entire survey period was 0.79, it declined to 0.62 during the peak period of the epidemic. Furthermore, the odds ratio was 0.42 by the multiple logistic model. Among the vaccinated group, the pattern in the increase of HI titer after vaccination varied depending on the species of vaccine antigen. In addition, the frequency of febrile episodes above 38 degrees C was significantly lower in the group which had an HI titer to A/Sydney antigen of 1:40 or more than in these with values below 1:40. CONCLUSION: The relative risk of febrile episodes above 38 degrees C during the influenza prevalent season was 0.62 or below, and vaccine efficacy was 38 percent or above. Considering the significant difference in the frequency of febrile episodes between the groups with HI titers above and below 1:40, it is necessary to study strategies for those with a low response.

Child↗
PubMed2002

Lipid accumulation in smooth muscle cells under LDL loading is independent of LDL receptor pathway and enhanced by hypoxic conditions.

OBJECTIVE: The effect of a variety of hypoxic conditions on lipid accumulation in smooth muscle cells (SMCs) was studied in an arterial wall coculture and monocultivation model. METHODS AND RESULTS: Low density lipoprotein (LDL) was loaded under various levels of oxygen tension. Oil red O staining of rabbit and human SMCs revealed that lipid accumulation was greater under lower oxygen tension. Cholesterol esters were shown to accumulate in an oxygen tension-dependent manner by high-performance liquid chromatographic analysis. Autoradiograms using radiolabeled LDL indicated that LDL uptake was more pronounced under hypoxia. This result holds in the case of LDL receptor-deficient rabbit SMCs. However, cholesterol biosynthesis and cellular cholesterol release were unaffected by oxygen tension. CONCLUSIONS: Hypoxia significantly increases LDL uptake and enhances lipid accumulation in arterial SMCs, exclusive of LDL receptor activity. Although the molecular mechanism is not clear, the model is useful for studying lipid accumulation in arterial wall cells and the difficult-to-elucidate events in the initial stage of atherogenesis.

Animals↗
PubMed2002

Development and application of an enzyme immunoassay based on a monoclonal antibody against gonyautoxin components of paralytic shellfish poisoning toxins.

With a gonyautoxin 2/3 (GTX2/3)-specific monoclonal antibody (designated GT-13A) and a saxitoxin-horseradish peroxidase conjugate (STX-HRP), a direct competitive enzyme immunoassay (GTX-EIA) was established and its sensitivity to various toxin components was investigated. The concentrations resulting in 50% inhibition of the binding of STX-HRP to the solid-phase GT-13A antibody for GTX2/3, decarbamoyl-GTX2/3 (dc-GTX2/3), N-sulfocarbamoyl-GTX2/3 (C1/2), GTX1/4, STX, and neosaxitoxin (neoSTX) in GTX-EIA were found to be 0.28, 0.41, 0.52, 3.46, 4.06, and 89.37 ng/ml, respectively. When the minimum detection limit was assumed to be at a toxin concentration causing 30% inhibition of the binding of STX-HRP to the solid-phase GT-13A antibody, the detection limits for GTX2/3, dc-GTX2/3, C1/2, GTX1/4, STX, and neoSTX were found to be 0.15, 0.18, 0.19, 1.09, 1.50, and 22.93 ng/ml, respectively. These results indicate that all of the GTX components examined and STX are detectable at concentrations lower than the regulatory limit of 80 microg/100 g of shellfish tissue, even when a minimum dilution factor of 100 is applied to tissue extracts with the extraction procedure of the Association of Official Analytical Chemists. Therefore, GTX-EIA is thought to be a useful qualitative screening method for GTX components and STX in the mass monitoring of toxin-contaminated shellfish.

Animals↗
PubMed2002

Extensive oligonucleotide microarray transcriptome analysis of the rat cerebral artery and arachnoid tissue.

Cerebral vessels have certain distinct anatomical and developmental characteristics which are well known, but their characteristic genetic expression profile remains as yet only poorly understood. We investigated gene expression in the rat cerebral artery in comparison with the rat descending aorta, two locations which have obviously different anatomical and developmental characteristics. Since the contamination of cerebral small arteries by arachnoid tissue is to a certain extent inevitable, we also performed a gene expression analysis of arachnoid tissue as a background. In an effort to obtain the necessary quality and quantity of total RNA, a novel freeze-fracture apparatus minimizing the time required for the entire procedure from tissue separation to RNA preparation was used. With the material obtained, a group of genes highly expressed in each tissue was detected by oligonucleotide microarray analysis. In the circle of Willis, peptide-19 (PEP-19), connexin-37 (CXN-37), growth arrest-and DNA damage-inducible gene (GADD45), and the putative G protein coupled receptor RA1c, Notch-1, and jagged-1 were predominantly expressed. In arachnoid tissue, bone morphologic protein (BMP)-7, BMP-6, beta defensin-1, neuroendocrine protein 7B2, thiol-specific antioxidant protein, IL-18, beta-chain clathrin-associated protein complex AP-1, and angiopoietin-2 were highly expressed. In the aorta, most of the abundantly expressed genes related to lipid metabolism. By means of oligonucleotide microarray analysis, the distinct gene expression profiles in the circle of Willis arachnoid tissue, and aorta were made evident. From these findings it is reasonable to conclude that a functional interaction exists between the circle of Willis and arachnoid tissue.

Animals↗
PubMed2002

[Contamination of oyster sea farm with the Norwalk virus: mechanisms and control].

The Norwalk virus(NV) is widely known as a cause of nonbacterial food poisoning, infant diarrhea, and acute gastroenteritis in the winter months between November and March. While it is strongly suspected that NV that is excreted by humans flows into coastal seawaters via rivers and wastewater treatment facilities to contaminate oysters that are grown in farms in the area, light has yet to be shed on the behavior of this virus in the natural environment. We therefore conducted a polymerase chain reaction (PCR) survey of NV levels in the aquatic environment of the oyster bed area of the Shima region in Mie Prefecture, whereupon the NV was detected in marine sediment, oysters, and mule clams even during the summer months, when food poisoning is infrequent. In order to assess their similarity to human-derived strains, the detected viruses and their human-derived counterparts were subjected to genetic analysis, whereupon some of the detected viruses were found to be remarkably similar to those that were previously detected in humans infected with NV. In the interests of examining methods for decontaminating NV-contaminated oysters, we also conducted an assessment on a system of virus decontamination that focuses on seawater temperature and oyster metabolism, using Poliovirus Sabin strain. The decontamination system mentioned above was a closed loop, water circulating system, built on the same principles as those actually in use at oyster farms. Our experiment indicated that at seawater temperatures of both 10 degrees C and 20 degrees C, virus placed into the water tank was rapidly incorporated into the midgut glands of the oysters. Thereafter, when seawater irradiated with UV was circulated, the virus count in the oysters fell from 1/1,000 to 1/10,000 within 6 hours. These results indicated the utility of this system for virus decontamination, suggesting the possibility of significantly alleviating the risk of NV infection in humans by using this system to maintain the seawater temperature within the decontamination tank above a certain temperature, and to perform decontamination with an adequate water flow.

Animals↗