Biomedical subjects

M Okada

Publications and source records attributed to M Okada.

At least 55 records · Page 3Linked to original sources

PubMed2003

Stimulation of bacterial activity by the addition of different PACs.

The effect of bacterial adhesion on powdered activated carbon on bacterial activity in non-toxic wastewater was studied and the difference of powdered activated carbon species on the stimulation of bacterial activity was also evaluated using eight kinds of powdered activated carbon. Pure cultures of Escherichia coli K-12, which can reduce NO3- to NO2- in anoxic conditions, were used. Specific nitrate reduction activity was used as an indicator of bacterial activity. The higher specific nitrate reduction rates were noted in cultures with powdered activated carbon than without powdered activated carbon or with Kaolin. The specific nitrate reduction rate with powdered activated carbon was up to about 1.4 times as highas those without powdered activated carbon. The stimulation of bacterial activity was induced by the adhesion of bacterial cells onto powdered activated carbon. There are powderedactivated carbons that can stimulate bacterial activity, whereas not all the powdered activated carbon can stimulate bacterial activity. Surface characteristics like Brunauer-Emmett-Teller specific surface areas, total surface acidity, oxygen functional groups, total surface basicity, surface charge, pH(pzc), iodine number, concentrations of metals, electric resistance, free radical concentration and adsorption capacity of formate did not related with the stimulation of the bacterial activity.

Carbon↗

PubMed2003

Effect of P-deficiency on photoassimilate partitioning and rhythmic changes in fruit and stem diameter of tomato (Lycopersicon esculentum) during fruit growth.

Tomato (Lycopersicon esculentum) plants were grown in liquid culture inside the greenhouse of Hiroshima University, Japan. At the first fruiting stage, P was withdrawn from the rooting medium for a period of 19 d and its effect was studied on photosynthesis, stomatal conductance, transpiration, partitioning of 13C and 15N, P contents of various organs, and changes in stem and fruit diameter of the plant in order to identify the mechanism of resource management on the part of the plant at low P. Compared to the control, P-deficiency treatment decreased biomass growth of all organs except the roots. The treatment also depressed leaf photosynthesis, stomatal conductance and diameter of fruit and stem after a lag period of about 1 week. The stem diameter of the plant shrank during daytime and expanded during the night; the adverse effect of P-deficiency on stem diameter change was more evident during the night than the day. The circadian rhythm in fluctuations of diameter was less manifested in the fruit compared with the stem. P-deficiency induced daytime shrinkage and reduced night expansion of fruit. However, within the plant, P-deficiency encouraged partitioning of 13C, 15N and P into the fruit at the cost of autotrophic organs such as leaves and the upper parts of the stem. The results were discussed in the light of a plausible effect of P-deficiency on water relations of the plant. It is concluded that, in spite of the preference in partitioning of C and N received within the plant parts, assimilate flow into the fruit is limited at low-P compared with the control, owing to the restriction in fruit expansion.

Biomass↗

PubMed2003

DNA methylation in systemic lupus erythematosus.

Recent studies on epigenetics, including DNA methylation and its regulatory enzymes, seem likely to contribute to elucidation of the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE), although the relationship between DNA methylation and SLE has long been the subject of investigation. To obtain a deeper understanding of the role of DNA methylation in the induction of SLE, we reviewed the relationship between DNA methylation and SLE based on findings reported in the literature and our own data. Various studies, including ours, have indicated the possible importance of DNA methylation, especially hypomethylation, in the etiology of SLE. These epigenetic studies may give us clues towards elucidation of the pathogenesis of SLE and development of new therapeutic strategies for this disease.

DNA Methylation↗

PubMed2003

Alport syndrome and benign familial hematuria (thin basement membrane disease) in two brothers of a family with hematuria.

Alport syndrome (AS) and benign familial hematuria (BFH) are inherited disorders of the glomerular basement membrane, which are sometimes difficult to differentiate at the early stage without type IV collagen staining of the renal basement membrane. Previous studies have indicated that mutation of type IV collagen alpha4 gene may be responsible for both BFH and AS. We report here a Japanese family with consanguinity, in which autosomal-recessive AS and BFH were separately identified in two brothers on the basis of findings of electron microscopy and type IV collagen chain staining of the renal biopsy specimens. Their parents, being first cousins, paternal uncle and grandmothers were found to have hematuria. Our observations suggest that BFH patients were heterozygous carriers of autosomal-recessive AS.

Basement Membrane↗

PubMed2003

Localization of breast sentinel lymph nodes by MR lymphography with a conventional gadolinium contrast agent. Preliminary observations in dogs and humans.

PURPOSE: To test the capability of an indirect MR lymphography (MRLG) using a conventional extracellular gadolinium (Gd)-based contrast agent for localizing breast sentinel lymph node (SLN). METHODS: A total of 1 and 0.5 ml of undiluted gadopentetate dimeglumine were injected subcutaneously into the two periareolar areas overlying each caudal mammary gland in 10 female dogs. Contiguous 2-mm-thick fast gradient echo MR images were acquired through the upper breast and axilla before and for 60 min after gentle massage at the injection sites, yielding 3D displays. The localized SLN was resected from the living animals, followed by post mortem examinations. MRLG (1 ml contrast agent injected) was also attempted in 5 female volunteers. RESULTS: Even with 0.5-ml contrast agent, the MRLG clearly visualized the connection of SLN and lymphatic vessels directly draining from the injection sites, and the remaining distant nodes, with the maximal enhancement peaks within 10 min after massage. The 3D images provided comprehensive anatomy of these lymphatic pathways in each axilla. Of the 20 SLN and 128 distant nodes visualized on the MRLG, all the SLN (100%) and 107 (83.5%) distant nodes could be resected pre- and post mortem, in good correlation with the locations and sizes on the MR images. MRLG also effectively localized SLN in the volunteers, without significant adverse effects. CONCLUSION: An indirect MRLG using small volumes of conventional Gd-based contrast agent may have potential for accurate identification and surgical biopsy of breast SLN.

Animals↗

PubMed2003

Flat and depressed lesions of the colon and rectum: Pathogenesis and clinical management.

INTRODUCTION: It is not clear whether flat lesions play a role in the pathogenesis of colorectal carcinoma. Flat lesions are being increasingly recognised with new colonoscopic techniques. MATERIALS AND METHODS: A total of 10,939 consecutive colonoscopies were performed over a 9-year period. After bowel preparation with polyethylene glycol electrolyte lavage solution, high-resolution video colonoscopy and indigocarmine spraying were performed to detect flat lesions. All lesions suggesting neoplastic change were removed by polypectomy or surgery. Cancers invading beyond the submucosal layer were excluded from this analysis. The gross appearance of flat-type lesions was classified as flat elevated type or flat depressed type based on the presence or absence of central depression. RESULTS: A total of 5408 neoplastic lesions were index lesions, including 5035 adenomas and 373 carcinomas (124 with submucosal invasion). The prevalence of flat depressed and flat elevated lesions were 2.8% and 18.1%, respectively. Submucosal invasion rates were 17.1% in the flat depressed, 0.8% in the flat elevated, 1.6% in the sessile, 4.0% in pedunculated lesions and 9.3% in creeping lesions. The submucosal invasion rate in the flat depressed lesions was significantly higher than in any others, except for creeping lesions (P = 0.06). The percentage of flat elevated and flat depressed carcinomas among all carcinomas invading the submucosa was 6.5% and 21.0%, respectively. CONCLUSION: Flat lesions were common during routine colonoscopy. One-quarter of colorectal cancers may be derived from flat lesions. Training in dye spray technique may result in a higher detection rate of flat colonic lesions.

Adenoma↗

PubMed2003

Effect of non-aqueous phase liquid on biodegradation of PAHs in spilled oil on tidal flat.

Biodegradation rates of polycyclic aromatic hydrocarbons (PAHs) in spilled oil stranded on tidal flats were studied using model reactors to clarify the effects of NAPL on the biodegradation of PAHs in stranded oil on tidal flat with special emphasis on the relationship between dissolution rates of PAHs into water and viscosity of NAPL. Biodegradation of PAHs in NAPL was limited by the dissolution rates of PAHs into water. Biodegradation rate of chrysene was smaller than that for acenaphthene and phenanthrene due to the smaller dissolution rates. Dissolution rates of PAHs in fuel oil C were smaller those in crude oil due to high viscosity of fuel oil C. Therefore, biodegradation rates of PAHs in fuel oil C were smaller than those in crude oil. Biodegradation rates of PAHs in NAPL with slow decrease rate like fuel oil C were slower than those in NAPL with rapid decrease like crude oil. The smaller decrease rate of fuel oil C than crude oil was due to higher viscosity of fuel oil C. Therefore, not only the dissolution rate of PAHs but also the decrease rates of NAPL were important factors for the biodegradation of PAHs.

Biodegradation, Environmental↗

PubMed2003

Numerical modelling of the petroleum oil penetration into sandy beach sediments.

A numerical model describing the penetration of petroleum oil into sandy beach sediments was developed to assess the behavior of stranded oil at tidal zone as a result of tanker accidents, and so on. To understand the penetration behavior, penetration rate of three species of petroleum oil (two species of fuel oil C and one species of crude oil) was observed experimentally with artificial tidal zone equipment. As a consequence, two types of oil were distinguished from the viewpoint of penetration rate. One (fuel oil C-1) kept its homogeneity in composition and showed relatively rapid penetration, the other (fuel oil C-2 and crude oil) became heterogeneous and slow in penetration. Considering this aspect as the adsorption of polar compounds (i.e. asphaltenes) on the sediment surface, a numerical model that described oil penetration into sandy beach was developed. As a result, the difference in penetration rate between these two types of oil could not be replicated sufficiently only by consideration of the adsorption. However, the change of a parameter value which represents the apparent viscosity of oil led to good agreement with observations. Simulation results indicated that when fuel oil C or crude oil used in this study was stranded at a sandy beach located in Hiroshima Bay, Japan, 2 to 39% of total stranded oil might penetrate into the deeper zone (> 3 cm in depth) over 50 days.

Adsorption↗

PubMed2002

Hydrogen peroxide induces apoptosis of osteocytes: involvement of calcium ion and caspase activity.

We hypothesized that reactive oxygen species play an important role in avascular/ischemic osteonecrosis. When isolated chick osteocytes were cultured with hydrogen peroxide, annexin V binding, which is the earliest marker of apoptosis, increased in a dose-dependent fashion. Hydrogen peroxide also induced the activation of caspase-3 and increase in cytosolic Ca2+. Treatment with BAPTA/AM (cheletor of cytosolic Ca2+) and Ac-DEVD-cho (caspase inhibitor) attenuated hydrogen peroxide-induced apoptosis. These data demonstrated the signal transduction pathways that participate in this hydrogen peroxide-induced cell damage.

Animals↗

PubMed2002

Molecular epidemiology and phylogenetic analysis of Sapporo-like viruses.

Sapporo-like viruses (SLV) are a causative agent of gastroenteritis in humans. SLV-specific primers were newly designed in capsid protein-coding region and 529 fecal samples collected from gastroenteritis patients were tested. Thirty-five samples (6.6%) were found to be positive by reverse transcriptase-polymerase chain reaction (RT-PCR). Out of 35 positive samples, 25 were classified into a genogroup SG-I, typified by the Sapporo virus, and 9 were classified as a genogroup SG-II, typified by the London virus. Interestingly, one sample could not be classified into any genogroup, which suggests that it may be part of a new SLV genogroup. The RT-PCR used in this study appeared to be capable of widely detecting SLV genogroups, and it was seen to be powerful enough for molecular epidemiological as well as phylogenetic studies on SLV.

Adolescent↗

PubMed2002

Preparation of agricultural residue anion exchangers and its nitrate maximum adsorption capacity.

Anion exchangers were prepared from different agricultural residues (AR) after reaction with epichlorohydrin and dimethylamine in the presence of pyridine and N,N-dimethylformamide (EDM method). Agricultural residues anion exchangers (AR-AE) produced by the EDM method were inexpensive and showed almost the same NO3- removal capacities as Amberlite IRA-900. AR-AE produced from AR with higher hemicelluloses, lignin, ash and extractive contents resulted in the lower yields. Sugarcane bagasse with the highest alpha-cellulose contents of 51.2% had the highest yield (225%) and lowest preparation cost. The highest maximum adsorption capacity (Qmax) for nitrate was obtained from rice hull (1.21 mmol g(-1)) and pine bark natural exchangers (1.06 mmol g(-1)). No correlation was found between Qmax and alpha-cellulose content in the original AR. AR-AE produced from different AR demonstrated comparable Qmax due to the removal of non-active compounds such as extractives, lignin and hemicelluloses from AR during the preparation process. Similar preparation from pure cellulose and pure alkaline lignin demonstrated that the EDM method could not produce anion exchangers from pure lignin due to its solubilization after the reaction with epichlorohydrin.

Adsorption↗

PubMed2002

A new procedure to produce lignocellulosic anion exchangers from agricultural waste materials.

Two lignocellulosic agricultural waste materials (LCM), sugarcane bagasse (BG) and rice hull (RH), were converted into weak-base anion exchanger and evaluated for their exchanger capacity for nitrate. Pure cellulose (PC) and pure alkaline lignin (PL) were also used as reference materials to elucidate possible reactivity in LCM. Epoxy and amino groups were introduced into BG, RH, PC and PL substrates after the reaction with epichlorohydrin and dimethylamine in the presence of pyridine and an organic solvent N,N-dimethylformamide (DMF). Amino group incorporation into cellulose decreased with the presence of water in the reaction mixture and increased with the reaction time and presence of a catalyst (pyridine). The highest maximum nitrate exchange capacity (Qmax) and yields of the prepared exchangers was obtained from PL (1.8 mmol g(-1) and 412.5%), followed by BG (1.41 mmol g(-1) and 300%), PC (1.34 mmol g(-1) and 166%) and RH (1.32 mmol g(-1) and 180%). The proposed synthetic procedure was effective in modifying PL, PC and LCM chemically resulting in a higher yield and nitrate removal capacity.

Agriculture↗

PubMed2002

Thrombotic thrombocytopenic purpura and hemolytic uremic syndrome following allogeneic bone marrow transplantation.

We monitored the levels of various cytokines and chemokines, as well as an adhesion molecule and factors related to vascular endothelial damage, in three patients with thrombotic thrombocytopenic purpura and hemolytic uremic syndrome after bone marrow transplantation. Measurements were done at the onset of this condition and during plasma exchange for treatment. At the onset of thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, the levels of interleukin-8, thrombomodulin, and plasminogen activator inhibitor-1 were all markedly increased. A close relationship was observed between improvement in symptoms by plasma exchange and a decrease in interleukin-8 level, suggesting that this chemokine may be related to the development of thrombotic thrombocytopenic purpura and hemolytic uremic syndrome after bone marrow transplantation.

Adult↗

PubMed2002

The transmembrane form of TNF-alpha drives autoantibody production in the absence of CD154: studies using MRL/Mp-Fas(lpr) mice.

It is generally accepted that the interaction between CD40 and its ligand (CD154) plays a decisive role in contact-dependent help for T and B cells. In CD154-deficient MRL/Mp-Fas(lpr) (MRL/lpr) mice, however, high titres of IgG2a-type autoantibodies against small nuclear ribonucleoproteins (snRNPs) are observed. We successfully isolated two CD154-deficient MRL/lpr Th1 lines, which could provide B cell help for anti-snRNP antibody production. The proliferative responses of the Th1 cell lines were MHC class II (I-Ek)-restricted. Although syngeneic B cell proliferation was induced by Th1 lines in both a contact-dependent and -independent manner, the soluble form of TNF-alpha (sTNF-alpha) was not involved in contact-independent B cell proliferation. On the other hand, both anti-TNF-alpha and TNF-receptor 2 (TNF-R2, p75) monoclonal antibody (MoAb) blocked contact-dependent B cell proliferation, suggesting that the transmembrane form of TNF-alpha (mTNF-alpha)-TNF-R2 co-stimulation participates in B cell activation. Similarly, anti-TNF-alpha and TNF-R2 MoAb inhibited anti-snRNP antibody production in vitro, but anti-CD154 or TNF-R1 MoAb did not. These results indicate that the interaction of mTNF-alpha on activated Th1 cells with TNF-R2 on B cells may be involved in the autoimmunity seen in MRL mice, and that the blockade of CD40-CD154 co-stimulation may not always be able to suppress some Th1-related manifestations of lupus.

Animals↗

PubMed2002

Comparison of automated haematology analysers for detection of apoptotic lymphocytes.

Automated haematology analysers can rapidly provide accurate blood cell counts and white blood cell differentials. In this study, we evaluated four different haematology analysers for the detection of apoptotic lymphocytes in peripheral blood: MAXM A/L Retic, H*2, Cell-Dyn 3500 and NE-8000. With the MAXM A/L Retic haematology analyser, the apoptotic lymphocyte cluster appeared below the original lymphocyte cluster on the volume/DF1, and to the right under the original lymphocyte cluster on the volume/DF2 scattergrams. With the H*2 haematology analyser, the apoptotic polymorphonuclear lymphocytes produced a higher lobularity index on the BASO channel. With the Cell-Dyn 3500 haematology analyser, the apoptotic lymphocyte cluster appeared to the right side of the original lymphocyte cluster on the 0D/10D scattergram and to the left side of the polymorphonuclear cluster on the 90D/10D scattergram. With the NE-8000 haematology analyser, the apoptotic lymphocyte cluster was not distinguishable. Thus, apoptotic lymphocytes are readily detected on scattergrams generated by selected haematology analysers.

Apoptosis↗

PubMed2002

Influence of parents' oral health behaviour on oral health status of their school children: an exploratory study employing a causal modelling technique.

OBJECTIVES: The aim of this study was to examine the simultaneous interrelationships between parents' oral health behaviour and the oral health status of their school children. SAMPLE AND METHODS: Subjects comprised 296 pairs of parents (mother or father) and their children at an elementary school in Hiroshima. The child's dental examination was performed using the World Health Organization (WHO) caries diagnostic criteria for decayed teeth (DT) and filled teeth (FT). The Oral Rating Index for Children (ORI-C) was used for the child's gingival health examination. Hiroshima University Dental Behavioural Inventory (HU-DBI) was used for the assessment of the parents' oral health behaviour. A parent-child behavioural model was tested by the linear structural relations (LISREL) programme. RESULTS: There was a significant correlation between DT and ORI-C (r = - 0.168; P < 0.01). Correlation was found between ORI-C and oral health behaviour in children (OHB-C) (r = 0.182; P < 0.01). OHB-C was significantly associated with the HU-DBI (r = 0.251; P < 0.001). The hypothesized model after some revisions was found to be consistent with the data (chi(2) = 1.3, d.f. = 6, P = 0.97; Goodness of Fit Index = 0.999). Parents' oral health behaviour affected their children's oral health behaviour (P < 0.001). Children's oral health behaviour affected their DT through its effect on gingival health level. Parents' oral health behaviour also had a significant direct effect on their children's DT (P < 0.05). Children's grade affected both DT and their oral health behaviour. CONCLUSIONS: Parents' oral health behaviour could influence their children's gingival health and dental caries directly and/or indirectly through its effect on children's oral health behaviour.

Adult↗

PubMed2002

Lessons from similarities between SLE and HIV infection.

OBJECTIVE: We attempted to obtain deeper understanding of systemic lupus erythematosus (SLE) and human immunodeficiency virus (HIV) infection through comparative studies between both diseases. METHOD: For this purpose, we reviewed and discussed lessons from similarities in both diseases based on our own and reported findings in literatures. RESULT: Such comparative studies may contribute to the progress in understanding the clinical or pathogenetic features of these diseases. CONCLUSION: Further studies into the relationship between SLE and HIV infection may bring to light important clues to assist in the development of better treatments for each disease.

HIV Infections↗

PubMed2002

[Long-term results after endovascular treatment of peripheral arterial occlusions].

OBJECTIVE: Presentation of our long-term results with endovascular treatment of peripheral arterial occlusive disease. PATIENTS AND METHODS: We report on 115 patients (98 male, 17 female), average 67 years, with 141 occlusions or stenoses in the iliac or femoral arteries that were treated by laser-angioplasty. RESULTS: Excellent primary results were obtained in 93 % of the stenoses and 74 % of the occlusions. The results depended on the length of the lesions. In femoro-popliteal lesions < 10 cm length a success rate of 98 % could be observed, in lesions > 10 cm it was 71 %. The same was true for iliac lesions: the clinical success rate was 91 % in lesions < 5 cm as compared to 44 % in lesions > 5 cm. The long-term results were even satisfactory, the patency rate ranged to 85 % in stenoses and 75 % in occlusions, resp. CONCLUSION: Laser-angioplasty in our hands is an excellent treatment modality for occlusions/stenoses of the peripheral arteries and coronaries, a strong indication anticipated.

Adult↗