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Biomedical subjects

N Watanabe

Publications and source records attributed to N Watanabe.

At least 37 records · Page 2Linked to original sources

Curdlan sulphate in human severe/cerebral Plasmodium falciparum malaria.

Preclinical studies have shown that curdlan sulphate (CRDS), a sulphated 1-->3-beta-D glucan, inhibits Plasmodium falciparum in vitro and down-modulates the immune response. A direct, non-specific effect on cytoadherence and rosetting may be predicted, as has been described with other sulphated polysaccharides, e.g. heparin. The anticoagulant effect of CRDS is 10-fold lower than heparin. Curdlan sulphate has, therefore, emerged as a candidate for adjunct medication in the treatment of severe/cerebral malaria. Two clinical studies were conducted using CRDS as adjunct medication to conventional therapy (artesunate) in patients with severe and severe/cerebral malaria. Both studies were double-blind and placebo-controlled to evaluate the efficacy and safety of the combination. Curdlan sulphate appeared to reduce the severity of the disease process, e.g. fever clearance time was shortened. Due to the small number of patients, there was no difference in mortality. The two treatment arms in both studies showed similar results for all laboratory parameters. The only adverse event recorded during CRDS treatment was an increase in activated partial thromboplastin time. This can be monitored easily. It seems that the patients who may benefit most are severe/cerebral cases with no organ damage on admission.

Adolescent↗

Cell signalling by oxidized lipids and the role of reactive oxygen species in the endothelium.

The controlled formation of ROS (reactive oxygen species) and RNS (reactive nitrogen species) is now known to be critical in cellular redox signalling. As with the more familiar phosphorylation-dependent signal transduction pathways, control of protein function is mediated by the post-translational modification at specific amino acid residues, notably thiols. Two important classes of oxidant-derived signalling molecules are the lipid oxidation products, including those with electrophilic reactive centres, and decomposition products such as lysoPC (lysophosphatidylcholine). The mechanisms can be direct in the case of electrophiles, as they can modify signalling proteins by post-translational modification of thiols. In the case of lysoPC, it appears that secondary generation of ROS/RNS, dependent on intracellular calcium fluxes, can cause the secondary induction of H2O2 in the cell. In either case, the intracellular source of ROS/RNS has not been defined. In this respect, the mitochondrion is particularly interesting since it is now becoming apparent that the formation of superoxide from the respiratory chain can play an important role in cell signalling, and oxidized lipids can stimulate ROS formation from an undefined source. In this short overview, we describe recent experiments that suggest that the cell signalling mediated by lipid oxidation products involves their interaction with mitochondria. The implications of these results for our understanding of adaptation and the response to stress in cardiovascular disease are discussed.

Animals↗

Phase I clinical trial and pharmacokinetic evaluation of NK911, a micelle-encapsulated doxorubicin.

NK911 is a novel supramolecular nanocarrier designed for the enhanced delivery of doxorubicin (DXR) and is one of the successful polymer micelle systems to exhibit an efficient accumulation in solid tumours in mice. The purpose of this study was to define the maximum-tolerated dose (MTD) and dose-limiting toxicities (DLTs) of NK911 and to evaluate its pharmacokinetic profile in man. NK911 was given intravenously to patients with solid tumours every 3 weeks using an infusion pump at a rate of 10 mg DXR equivalent min(-1). The starting dose was 6 mg DXR equivalent m(-2), and the dose was escalated according to the accelerated titration method. A total of 23 patients participated in this study. Neutropenia was the predominant haematological toxicity, and grade 3 or 4 neutropenia was observed at doses of 50 and 67 mg m(-2). Common nonhaematological toxicities were mild alopecia, stomatitis, and anorexia. In the dose identification part of the study, DLTs were observed at a dose of 67 mg m(-2) (grade 4 neutropenia lasting more than 5 days). Thus, this dosage level was determined to be the MTD. Infusion-related reactions were not observed in any cases. The C(5 min) and area under the concentration curve parameters of NK911 exhibited dose-dependent characteristics. Among the 23 patients, a partial response was obtained in one patient with metastatic pancreatic cancer. NK911 was well tolerated and produced only moderate nausea and vomiting at myelosuppressive dosages. The recommended phase II dose was determined to be 50 mg m(-2) every 3 weeks.

Aged↗

Practical means for the study of electron correlation in atoms.

Electron correlation is basic to the understanding of a diverse range of physical and chemical phenomena, yet, there have been no direct measurements of the correlated motion of electrons. Measurement of the correlated momenta of atomic electrons is possible via electron-impact double ionization provided that the ionizing collisions are both impulsive and binary, and the three-body scattering mechanism is known. The results reported here satisfy these conditions, and a practical means for the study of atomic electron correlation through measurement of two-electron momentum densities is presented.

Journal Article↗

A new method to immortalize primary cultured rat hepatocytes.

BACKGROUND: In conventional methods of establishing hepatocyte cell lines, the immortalizing gene alone is introduced into hepatocytes. We designed a new method in which not only the immortalizing gene, the simian virus-40 large T-antigen (SV-40 Tag) gene, but also a drug-resistant gene, under the control of an albumin enhancer/promoter, were introduced into hepatocytes to efficiently obtain immortalized hepatocyte cell lines. METHODS: The plasmid pAPUR contains the puromycin-resistant gene under the control of an albumin enhancer/promoter, and the pSVTag contains the early region of SV-40 enhancer/promoter and the SV-40 Tag gene. Both pAPUR and pSVTag were transferred into isolated rat hepatocytes by electroporation. After these cells were cultured on a collagen-coated dish for 24 hours, puromycin selection was started. Expression levels of albumin, alpha-fetoprotein (AFP), SV-40 Tag, and cytokeratin 19 (CK 19) in the transformed cells were evaluated by western analysis, immunocytochemical staining, and RT PCR. RESULTS: Approximately 3 weeks after transfection, five or six colonies appeared on the dish. Twenty strains were obtained by cloning these cells. All strains that were similar to immature hepatocytes expressed albumin and SV-40 Tag, although CK 19 was not detected. AFP expression was detected in 33% of these strains. CONCLUSIONS: All clones cotransfected by pAPUR and pSVTag expressed albumin. Our new method may be useful to establish hepatocyte cell lines.

Animals↗

Expansion of human CMV-specific cytotoxic T lymphocytes to a clinical scale: a simple culture system using tetrameric HLA-peptide complexes.

BACKGROUND: Recipients of allogeneic stem cell transplants (SCT) are at risk of human CMV infection during their immunocompromised period. The increasing number of reports of CMV isolates resistant to ganciclovir after transplantation has led us to attempt to develop alternative strategies for preventing or treating CMV infection. This study describes a system for generating sufficient numbers of CMV-specific cytotoxic T lymphocytes (CTL) for adoptive immunotherapy after SCT. METHODS: CMV-specific CTL were isolated from a single blood draw of a CMV-seropositive donor using PE-labeled HLA-A*0201/pp65(495-503) tetramers and anti-PE magnetic beads. A mixture of a tetramer-positive population and CD4(+) T lymphocytes was expanded to sufficient numbers for clinical application with IL-2 and immobilized anti-CD3 stimulation. RESULT: Starting from 50 mL of blood, we generated >10(7)/m(2) tetramer-positive CTL within 2 weeks. Flow cytometric analysis of expanded lymphocytes showed that purity of CMV peptide-specific CTL was >75%. Upon stimulation of HLA-A*0201-restricted CMV peptide, expanded CD8 T lymphocytes produced intracellular IFN-gamma. Purified CTL exhibited cytotoxic activity against CMV peptide-pulsed T2 cells and CMV-infected HLA-A*0201-positive fibroblasts, but not against HLA mismatched or uninfected target cells. Alloreactivity could be excluded in MLC. DISCUSSION: This simple, rapid culture system can be useful for adoptive immunotherapy after allogeneic SCT. We are now trying to adapt our laboratory scale study to a clinical scale study under good manufacturing practices (GMP) conditions.

Antigens, Viral↗

Hypoxia as a factor for 67Ga accumulation in tumour cells.

Recent reports have demonstrated that hypoxia induces the up-regulation of transferrin receptor expression in tumour cells. Tumour cells take up 67Ga in the form of a 67Ga-transferrin complex via transferrin receptors. As a result, we attempted to determine the influence of hypoxic conditions on 67Ga uptake in tumour cells. B16 melanoma cells and LS180 colon cancer cells were incubated in 95% air/5% CO2 or 95% N2/5% CO2 for 1 h at 37 degrees C. Cellular uptake of 67Ga citrate was subsequently determined at 20, 40, 60 and 90 min. Uptake of the 67Ga-transferrin complex pre-chelated in vitro was similarly assessed. The effect of hypoxia on 67Ga binding to serum proteins was also investigated. Both B16 and LS180 cells displayed increased cellular uptake of 67Ga citrate in N2 gas in comparison to that in air (P < 0.0001). Hypoxia more prominently influenced cellular uptake of Ga-transferrin relative to that of 67Ga citrate (P < 0.0001). Hypoxia did not affect the percentages of 67Ga radioactivity bound to protein in medium supplemented with fetal calf serum, indicating that the results were not caused by the alteration of 67Ga-transferrin formation. These findings suggest the role of tissue hypoxia with respect to accumulation of 67Ga in tumours, which is likely mediated by transferrin receptors.

Adenocarcinoma↗

The effect of bisphenol A and chlorinated derivatives of bisphenol A on the level of serum vitellogenin in Japanese medaka (Oryzias latipes).

2,2-bis (4-hydroxyphenyl) propane or Bisphenol A (BPA), has been reported to behave as an endocrine disrupter below acute toxic levels, and is widely present in the water environment. Although BPA is easily chlorinated, very little is reported on the effect of chlorinated BPA to the aquatic organisms. In this study, the estrogenic activities of BPA and its chlorinated derivatives were evaluated by the induction of vitellogenin (VTG) in the serum of mature male Japanese medaka. In addition, the effect of sodium hypochlorite on the decomposition of BPA was tested. The relative potencies of estrogenic activities of chlorinated BPA descended in the order 3,3'-diCIBPA>BPA> or =3-CIBPA>3,3',5-triCIBPA, and no estrogenic activity was observed in 3,3',5,5'-tetraCIBPA. Lowest Observed Effect Concentration (LOEC) and No Observed Effect Concentration (NOEC) for both 3-CIBPA and 3,3'-diCIBPA were 500 microg/L and 200 microg/L, respectively. LOEC for 3,3',5-triCIBPA was >500 microg/L. When BPA was reacted with sodium hypochlorite (24 hours; residual chlorine at 1 ppm), however, complete decomposition of BPA and its chlorinated derivatives was observed. The decrease in BPA and its chlorinated derivatives paralleled the decrease in estrogenic potency evaluated by the induction of vitellogenin (VTG) in the serum of mature male Japanese medaka.

Animals↗

[Morita therapy--a Japanese method for treating neurotic anxiety syndrome].

In Japan, the traditional Morita therapy is indicated for "shinkaishitsu" personalities, i.e., patients with neurotic anxiety disorder, especially with phobic and hypochondriac symptoms. The substantial theoretical basis and therapeutic principles were taken from Zen Buddhism, such as the development of the ego in the "space" between subject and object, the unity of body and soul, the distinction of inner and outer nature, and the principles of emptiness and nothingness. The treatment consists of an initial 7-day period of strict and isolated rest in bed followed by step-by-step occupational therapy and final reintegration into job and family. The founder of this therapy, Morita, sees the healing of the patients not in the removal of their fears but in the inner acceptance (arugamama) of the fears they have experienced--corresponding to an essential principle in Zen Buddhism. Nowadays, the method is used in a modified form adjusted to the change in mentality of Japanese patients.

Anxiety Disorders↗

Cryptic insertion and translocation or nondividing leukemic cells disclosed by FISH analysis in infant acute leukemia with discrepant molecular and cytogenetic findings.

Of 51 infants with acute leukemia, 13 (25%) had contradictory findings on 11q23/MLL rearrangements that were analyzed by cytogenetic and Southern blot methods: seven had rearranged MLL and normal karyotype, four had rearranged MLL and abnormal karyotype with no 11q23 translocation, and two had germline MLL and 11q23 translocations. Fluorescent in situ hybridization (FISH) analysis using an MLL probe that was performed to elucidate the discrepancy disclosed the presence of normal dividing cells and nondividing leukemic cells in the same bone marrow in five patients, and cryptic insertion or translocation in another five. Subsequent FISH and reverse transcription-polymerase chain reaction analysis identified the MLL-AF10, MLL-AF4, or MLL-AF1q fusions that were produced by the cryptic rearrangements in four of the five patients. In the remaining three patients, the breakpoint of 11q23 translocation was located distal to the MLL locus in one, and the discrepancy was unresolved in two. Thus, FISH should complement cytogenetic analysis when cytogenetic and molecular genetic findings are contradictory in infant leukemia, and when infant leukemia does not show 11q23 translocations or other specific translocations including t(7;12), t(1;22), etc that are recurrently found in infant leukemia.

Blotting, Southern↗

Estimation of fractional liver uptake and blood retention of 99mTc-DTPA-galactosyl human serum albumin: an application of a simple graphical method to dynamic SPECT.

The objective of this study was to investigate clinical utility of a graphical method for estimating liver uptake and blood retention of 99mTc-DTPA-galactosyl human serum albumin (99mTc-GSA; DTPA is diethylenetriaminepentaacetic acid) using dynamic single photon emission computed tomography (SPECT) data. When considering the kinetics of 99mTc-GSA, if it is assumed that (1) 99mTc-GSA distributes only between blood and liver, and (2) no metabolism of 99mTc-GSA occurs during the observation period, a plot of liver counts versus cardiac blood pool counts should, theoretically, be a straight line. From the slope and y intercept of a regression line, coefficients for converting count based liver and blood pool data to the per cent injected dose (%ID) can be calculated. The applicability of this method was tested on dynamic SPECT data from 30 patients with liver dysfunction. To validate this method, plasma concentrations (%ID/ml plasma) at 6, 15 and 30 min after the injection were estimated by this method and compared with the measured ones. To investigate the clinical significance of the per cent liver uptake, the value obtained by this method was compared with the results of conventional liver function tests, including serum albumin, the hepaplastin test, prothrombin time and indocyanine green clearance. In every data set, a plot of liver counts to cardiac blood pool counts was fitted well by a straight line (P<0.00001). Estimated plasma concentrations by this method showed good correlation with the measured ones at 6, 15 and 30 min after the injection (r=0.748, 0.838, 0.875, respectively; P<0.0001). The liver uptake determined by this method showed good correlation with the results of conventional hepatic function tests (P<0.002). The graphical method could provide an accurate estimate of %ID of 99mTc-GSA in blood without the need for blood sampling. The liver uptake determined by this method could be a simple but useful quantitative indicator of hepatic function.

Adult↗

Human beta-defensin-2 induction in Helicobacter pylori-infected gastric mucosal tissues: antimicrobial effect of overexpression.

The objective of this study was to understand more of the innate immune response to Helicobacter pylori by determining the expression of human beta-defensin-2 (hBD-2) in various gastric mucosal tissues and MKN45 gastric cancer cells with or without H. pylori. Semi-quantitative TaqMan RT-PCR and immunohistochemistry were carried out. The antimicrobial effects of a transfected hBD-2 gene against H. pylori were also evaluated. The results showed that hBD-2 was expressed in inflamed gastric mucosal tissues with H. pylori infection, but not in the absence of H. pylori infection. Expression was also detected in gastric cancers in patients with H. pylori infection. Expression was induced in the MKN45 gastric cancer cell line by H. pylori in a manner dependent on the abundance of bacteria. hBD-2-transfected 3T3J2-1 cells secreted hBD-2 protein into the culture medium and this protein inhibited growth of H. pylori completely. The results suggest that hBD-2 may be involved in the pathophysiology of H. pylori-induced gastritis.

Adult↗

In-vitro uptake of vitamin A by Plasmodium falciparum.

The vitamin-A uptake of Plasmodium falciparum was investigated by culturing a standard isolate of the parasite (FCR-3) with (3)H-labelled vitamin A, at concentrations of the vitamin corresponding to those normally present in human serum. The (3)H-labelled vitamin A accumulated in the parasites from each culture in a parasitaemia-dependent manner. The radioactivity detected in the parasites increased with parasite maturation from the ring to the late-trophozoite stage. In addition, most of the radioactivity incorporated into the parasite cells was in the cytoplasm. The accumulation of vitamin A in the cytoplasm of late trophozoites indicates that P. falciparum may use vitamin A, from its human host, as an antioxidant, to protect itself from oxidative stress while intra-erythrocytic. The amount of the vitamin taken up by the parasite in vitro is small compared with the deficit that sometimes causes severe hypovitaminosis A in malaria cases. Consumption of vitamin A by the parasites together with the systemic decreases in non-enzymatic antioxidants that are seen in malaria may together cause this characteristic hypovitaminosis.

Animals↗

[Perioperative management of patient with pulmonary operation associated with interstitial pneumonia].

The prognosis of patients complicated with interstitial pneumonia (IP) who undergo pulmonary operations is very poor if acute exacerbation occurs after the operation. We have experienced 6 cases in which operations were performed on lungs complicated with IP The first patient died due to acute exacerbation, but the subsequent 5 patients had good postoperative courses due to 1) short-term administration of low-dose steroid before and after the operation, 2) avoidance of administration of high concentration of oxygen during and after the operation, and 3) administration of erythromycin before and after the operation, 4) N-acetylcysteine inhalation and administration of dl-alpha-tocopherylnicotinate before and after the operation. It is thought that careful management of such patients is needed to prevent acute exacerbation even after discharge from hospital.

Humans↗