Biomedical subjects

Y Asano

Publications and source records attributed to Y Asano.

At least 235 records · Page 13Linked to original sources

PubMed2000

Stroke outcome in double-mutant antioxidant transgenic mice.

BACKGROUND AND PURPOSE: Both NO and superoxide cytotoxicity are important in experimental stroke; however, it is unclear whether these molecules act within parallel pathological pathways or as coreagents in a common reaction. We examined these alternatives by comparing outcomes after middle cerebral artery occlusion in male and female neuronal NO synthase (nNOS)-deficient (nNOS-/-) or human CuZn superoxide dismutase-overexpressing (hSOD1+/-) mice and a novel strain with both mutations. METHODS: Permanent middle cerebral artery occlusion was performed by use of the intraluminal filament technique (18 hours). Neurological status was scored, and tissue infarction volume was determined by 2,3,5-triphenyltetrazolium staining and image analysis. RESULTS: Hemispheric infarction volume was reduced in each transgenic strain relative to the genetically matched, wild-type, control cohorts (WT mice): nNOS-/- (80+/-6 mm(3)) and double-mutant (49+/-6 mm(3)) mice versus WT mice (114+/-7 mm(3)) and hSOD1+/- mice (52+/-7 mm(3)) versus WT mice (95+/-5 mm(3)). Human CuZn superoxide dismutase had a larger effect on mean infarction volume (30% of contralateral hemisphere) than did nNOS deficiency (46%). Although infarction volume was less in double-mutant mice compared with nNOS-/- mice, injury was not improved relative to hSOD1+/- mice. There was no difference in histological damage by sex within each strain; however, female nNOS-/- mice were not protected from ischemic injury, unlike male mutants. CONCLUSIONS: Superoxide generation contributes to severe ischemic brain injury in vivo to a greater extent than does neuronally derived NO. In vivo, significant superoxide scavenging by CuZn superoxide dismutase occurs within cellular compartments or through biochemical pathways that are not restricted to, and may be distinct from, neuronal NO/superoxide reaction and peroxynitrite synthesis.

Animals↗

PubMed2000

Establishment of monoclonal antibodies specific for Bacillus subtilis DB9011.

Bacillus subtilis DB9011 is a strain with useful functions for agriculture. To establish a method for the discrimination of this strain from others, monoclonal antibodies (MAbs) were prepared. Although two established MAbs (MAb9B6 and MAb14D2) cross-react with some other Bacillus strains in ELISA, only B. subtilis DB9011 vegetative cells are recognized by both MAbs. MAb14D2 recognizes flagellin, a 34-kDa unit protein of flagella. The two MAbs established will provide powerful tools with which detailed analysis of this bacterial strain can be obtained under environmental conditions.

Animals↗

PubMed2000

A modification of Mayer's tannic acid-ferric chloride staining method for demonstrating cellular membranous systems for light microscopy.

To observe cellular membranous systems under a light microscope, we modified Mayer's tannic acid-ferric chloride stain method by adding a treatment with hematoxylin after the original procedure. We used the modified tannic acid-ferric chloride (MTA-Fe) stain method to examine kidneys, liver, heart, trachea, epididymides and other organs of rats and dogs. The MTA-Fe stain clearly demonstrated the basement membrane, brush border, basolateral invaginations and cell processes in the kidneys which enabled easy differentiation of the S1 and S3 segments of proximal convoluted tubules. Our technique also demonstrated hepatic cell membranes and bile canaliculi in the liver, cross striations and longitudinal traveling of myofibrils in the heart, cilia of the epithelial cells in the trachea, and stereocilia and terminal bars in the epididymis. The MTA-Fe stain is a convenient method to visualize cellular membranous systems even for light microscopy. The stain has the advantages of using no toxic materials, simple and easy technique, little variation of staining results, and little fading for several months after staining.

Animals↗

PubMed2000

[High PTHrP level induced hypercalcemia and acute renal failure in a multiple myeloma patient].

Multiple myeloma causes various renal injuries by direct invasion of myeloma cells, AL amyloidosis and hypercalcemia. Hypercalcemia induced by myeloma has been thought to be a result of local osteolysis. Recently, however, it was noted that no significant difference existed in the degree of bone-destruction between hypercalcemic and normocalcemic multiple myeloma. The exact mechanisms of hypercalcemia induced by multiple myeloma remain unconfirmed. In the present study, we report a 70-year-old man, suffering from acute renal failure due to multiple myeloma and severe hypercalcemia. While the serum PTH level was low, PTHrP was markedly increased. Bone scintigraphy implied systemic increase in bone turnover in addition to cold spots corresponding to punched out lesions on bone Xp. After the intravenous administration of bisphosphonate, hypercalcemia and hot accumulation on bone scintigraphy were improved while the PTHrp level and bone destruction by myeloma cells were not improved. The present case suggests involvement of PTHrP in hypercalcemia of multiple myeloma.

Acute Kidney Injury↗

PubMed2000

[Clinical manifestations of the subfamily alpha-herpesvirinae in childhood].

Herpes simplex virus(HSV) and varicella-zoster virus(VZV) belonging to the subfamily of alpha-herpesvirinae have the capacity to establish latent infection in neural tissues and to reactivate from these sites. HSV infection is characterized by a vesicular eruption, fever, and other constitutional symptoms but frequently inapparent both in primary and recurrent infections. However, the infection produces a wide spectrum of illness ranging from the trivial fever blisters to the most severe fatal sporadic encephalitis and neonatal infection. In contrast, VZV develops varicella, a common contagious disease of childhood during primary infection and zoster by reactivation of latent virus acquired during varicella. In normal children, the systemic symptoms of both diseases are mild, whereas serious complications are often observed in children with deficiencies in cell-mediated immunity. Acyclovir has been the drug of choice for treatment of severe infection with HSV and VZV for approximately 2 decades. Now, two new agents, valacyclovir and famciclovir will supplant acyclovir for certain indications.

Alphaherpesvirinae↗

PubMed2000

MLL gene rearrangement in t(9;11) acute myelogenous leukemia with minimal myeloid differentiation (FAB subtype M0).

A 25-year-old man was diagnosed with acute myelogenous leukemia (AML), French-American-British (FAB) subtype M0, based on cytochemical and flow cytometric findings. Cytogenetic analysis revealed the chromosome translocations t(9;11)(p22;q23), and MLL gene rearrangement was identified by Southern blotting. In adult AML, MLL gene rearrangement was initially reported in FAB M4 and M5 cases, and recently in M1 and M2 cases, but was rare in M0 or M3 cases. Because the sensitivity of detecting MLL gene rearrangement by cytogenetic analysis is extremely low compared with Southern blotting analysis, the MLL gene may be involved in substantial numbers of adult AML cases, regardless of FAB subtype.

Adult↗

PubMed2000

Protective effect of bradykinin against glutamate neurotoxicity in cultured rat retinal neurons.

PURPOSE: To identify the localization and expression of bradykinin (BK)-B2 receptors in rat retina and examine the effects of BK on glutamate-induced neurotoxicity using cultured rat retinal neurons. METHODS: An immunohistochemical study using a specific antibody against BK-B2 receptor was performed with rat retina. Primary cultures were obtained from the retina of fetal rats (gestation day 17-19). Expression of BK-B2 receptor mRNA was determined by reverse transcription-polymerase chain reaction (RT-PCR) using total RNA obtained from cultured retinal neurons. Cultured cells were exposed to glutamate (1 mM) for 10 minutes and followed by incubation in glutamate-free medium for 1 hour. The effects of BK were assessed by simultaneous application of BK with glutamate. The neurotoxic effects on retinal cultures were quantitatively assessed by the trypan blue exclusion method. RESULTS: Immunohistochemical study demonstrated that BK-B2 receptors were expressed in the ganglion cell, inner nuclear layers, and outer nuclear layers. Furthermore, BK-B2 receptor mRNA expression was observed in cultured retinal neurons. Cell viability was markedly reduced by 10-minute exposure to 1 mM glutamate followed by a 1-hour incubation in glutamate-free medium. Simultaneous application of BK at concentrations of 0.001 to 1 microM with glutamate demonstrated dose-dependent protection against glutamate neurotoxicity. The protective action of BK (1 microM) was inhibited by simultaneous application of BK-B2 receptor antagonist, Hoe140 (1 microM). Furthermore, 1 microM BK had protective effects on neurotoxicity induced by 1 microM ionomycin, a calcium ionophore, and sodium nitroprusside (SNP, 500 microM), a nitric oxide (NO)-generating agent. However, BK did not inhibit neurotoxicity induced by 3-morpholinosydnonimine (SIN-1, 10 microM), an NO and oxygen radical donor. CONCLUSIONS: These results suggest that BK-B2 receptors were distributed in rat retinas and cultured retinal neurons and that BK had a protective action against glutamate neurotoxicity through BK-B2 receptors in cultured retinal neurons. It is suggested that BK-induced protection against glutamate neurotoxicity took place downstream to NO generation and upstream to oxygen radical generation.

Adrenergic beta-Antagonists↗

PubMed2000

Human herpesvirus 6 infection after living related liver transplantation.

The aim of the study was to investigate human herpesvirus-6 (HHV-6) infection after liver transplantation from living related donors, and to evaluate the reliability of the presence of HHV-6 DNA in plasma by the polymerase chain reaction (PCR) for monitoring active HHV-6 infection. EDTA peripheral blood was collected from 47 donor and recipient (16 males and 31 females, age 1-320 months) pairs at the time of transplantation and biweekly from these recipients after transplantation until 2 months after operation. Isolation of HHV-6 and serological assays were carried out to evaluate active HHV-6 infection in this study. The presence of the viral DNA in plasma was tested by nested PCR. Four clinical events, such as unexplained fever, thrombocytopenia, rejection, and central nervous system (CNS) involvement, were evaluated for clinical features of the virus infection. Risk factors for the virus activity after liver transplantation were also examined. HHV-6 activity was detected in 23 (49%) of the 47 recipients approximately 2-4 weeks after transplantation. All 9 isolates were HHV-6 variant B. The presence of the viral DNA in plasma correlated well with virus isolation and serology (P < 0.01). Only unexplained fever was associated statistically with HHV-6 activity after liver transplantation (P < 0. 01). If the recipient was seronegative to HHV-6 before transplantation, the recipient was more likely to develop the active virus infection after liver transplantation (P = 0.11). HHV-6 activity occurred in one-half of the recipients approximately 2-4 weeks after liver transplantation, and there was a close association between HHV-6 activity and unexplained fever following transplantation. Detection of the viral DNA in plasma by PCR is useful for monitoring active HHV-6 infection in these patients. Seronegative recipients were more likely to have evidence of active HHV-6 infection after liver transplantation.

Adolescent↗

PubMed2000

[Comparison of plasma exchange (PEX) vs. double filtration plasmapheresis (DFPP) with or without steroid administration in a case of MPO-ANCA-positive immune complex type crescentic glomerulonephritis].

The effect of plasmapheresis(PP) monotherapy and PP with corticosteroid administration were evaluated in a male with crescentic glomerulonephritis(CrGN). On the first admission, since he was positive for both anti-neutrophil cytoplasmic myeloperoxydase autoantibody(MPO-ANCA) and circulating immune complex(IC), the treatment was started with PP alone to reduce these autoantibodies immediately. During two months, three series of PP were performed: three sessions of plasma exchange (PEX) with fresh frozen plasma(FFP), two sessions of double filtration plasmapheresis(DFPP), and then, another two sessions of PEX, respectively. ANCA remained suppressed for 4 weeks after the first series of PEX, and increased thereafter. Subsequent DFPP caused a rebound of ANCA titer while the second PEX suppressed ANCA, at least, for 1 week. Though creatinine clearance(Ccr) improved after the first PEX and this level was maintained, ANCA increased again after the second PEX. Therefore the patient was treated with methyl-prednisolone(m-PSL) semipulse therapy followed by mild cocktail therapy including prednisolone(PSL) at 20 mg/day and mizoribine at 100 mg/day. In two weeks, ANCA and IC became negative and Ccr improved further. When PSL was tapered off, the ANCA became positive again. Since ANCA was not suppressed and Ccr declined gradually even after re-administration of oral PSL at 30-40 mg/day, PP was superimposed on steroid therapy with 3 sessions of DFPP and PEX, respectively. Ccr was improved, but ANCA was not sufficiently decreased by DFPP. Subsequent PEX was more efficient than DFPP in reducing the ANCA level. However, m-PSL semipulse was eventually required for complete suppression of ANCA. Thus PP was partially effective, but not sufficient as monotherapy. However it was considered advantageous as an adjunct therapy to reduce the dose of immunosuppressive drugs in CrGN. As to the mode of PP, PEX with FFP appeared to be more effective than DFPP in reducing the plasma ANCA level.

Aged↗

PubMed2000

[A case of autosomal recessive juvenile parkinsonism (AR-JP) with onset at the age of 6 years].

We report a 26-year-old woman with autosomal recessive juvenile parkinsonism (AR-JP). Her parents made consanguineous marriage. The disease started with dystonic posture of legs 20 years prior to the admission (6 years old). The equinovarus foot appeared at 9 years old and parkinsonism gradually developed. These symptoms were remarkably improved after sleep. Levodopa was effective on her parkinsonian symptoms. However, the response to levodopa gradually reduced. On admission, she presented with a masked face, marked rigidity, moderate retropulsion, postural tremor in the upper limbs and mild hyperreflexia in the lower limbs. Mutational analysis revealed homozygous deletion of exon 4 in perkin gene. This patient has youngest age of onset for ARJP to our knowledge.

Adult↗

PubMed2000

[Blood purification in toxicology].

Although toxic substances can be removed by blood purification techniques such as hemodialysis and hemoperfusion, the complete elimination of toxic substances from the whole body is difficult even if clearance values are high. Blood purification over in a limited time sometimes cannot prevent the death of patients, because the volume of distribution of toxic substances is usually very high. It should also be stressed that initial general management of patients is very important whenever blood purification procedures are utilized.

Hemodiafiltration↗

PubMed1999

A novel method for preparation of optically active alpha-monobenzoyl glycerol via lipase-catalyzed asymmetric transesterification of glycerol.

One-step synthesis of optically active alpha-monobenzoyl glycerol is described by lipasecatalyzed transesterification of benzoate derivatives with glycerol in 1,4-dioxane.

Catalysis↗

PubMed1999

Enhanced Fos expression in the hippocampus of El mice after short-term vestibular stimulation.

The El mouse is an animal model for human epilepsy. The mouse manifest seizures in response to periodically repeated vestibular stimuli such as being tossing-up. Although this technique has been traditionally employed to accelerate this disease in the mouse, its meaning remained obscure. The present study was conducted to estimate the effects of tossing-up stimuli on expression of c-fos, a well-known marker of neuronal activation. Expression of c-fos was significantly increased even after single tossing-up specimen. It was blocked by pretreatment of the mouse with MK-801, a NMDA receptor antagonist. A marked expression of the oncoprotein was observed in the granule cell layer of dentate gyrus and CA1-3 pyramidal cell layer in the hippocampus of the mouse. These results suggest that the El mice are genetically hyper-sensitive to the vestibular stimuli.

Animals↗

PubMed1999

Lipid A directly inhibits IL-4 production by murine Th2 cells but does not inhibit IFN-gamma production by Th1 cells.

Lipopolysaccharide (LPS) is known to be an immunopotentiator but its effect on cytokine production by Th1 and Th2 cells is unknown. We found that high amounts of LPS, its lipid A moiety, and a lipid A analog all induced a decrease in IL-4 production and an increase in IFN-gamma production when given to keyhole limpet hemocyanin (KLH)-restimulated lymph node cells prepared from KLH-primed mice. Lipid A was similarly found to inhibit IL-4 production by purified CD4+ T cells and Th2 clones activated with immobilized anti-CD3epsilon and anti-CD28 antibodies, suggesting that the inhibition is not indirectly mediated through effects on antigen-presenting cells. No inhibitory effect of lipid A was observed on IFN-gamma production by a Th1 clone. Production of both IL-4 by the Th2 clones and IFN-gamma by the Th1 clone were inhibited by the immunosuppressive agent cyclosporin A. These findings indicate that lipid A can directly inhibit IL-4 production by CD4+ T cells without inhibiting the production of IFN-gamma. Lipid A may therefore become a useful tool to study the intracellular events that differentiate Th1 and Th2 cells.

Animals↗

PubMed1999

Effect of interleukin 10 on the hematopoietic progenitor cells from patients with aplastic anemia.

The overproduction of cytokines with inhibitory effects on hematopoiesis is considered to play a role in the pathogenesis of aplastic anemia. While interleukin 10 (IL-10) is a cytokine production inhibitory factor, the possibility of immunosuppressive therapy using IL-10 for aplastic anemia has not been explored. In this study, therefore, we examined the effect of IL-10 on progenitor cells obtained from seven patients with severe aplastic anemia. Our study indicated that IL-10 dramatically enhanced the erythroid colony formation in a dose-dependent manner in two of the seven cases examined. When we examined the concentration of cytokines in the culture supernatants of unstimulated bone marrow cells, the spontaneous production of interferon-gamma (IFN-gamma) was observed in one of these two cases, and this production was completely inhibited by addition of IL-10. These findings suggested that IL-10 enhanced the erythroid colony formation by inhibiting the pathological production of IFN-gamma in this case. This study provides an experimental support for the clinical application of IL-10 in some patients with aplastic anemia.

Adult↗

PubMed1999

Aortoduodenal fistula arising from the dilatation of a knitted Dacron graft: report of a case.

A fatal aortoduodenal fistula occurred in a 72-year-old man who underwent a repair of an abdominal aortic aneurysm 16 years previously with a 20 x 10 mm bifurcated knitted Dacron graft. The aortic part of his bifurcated graft had dilated to 40 mm in diameter, with a discrepancy of 20 mm in the diameter between the graft and infrarenal aorta. The fourth portion of the duodenum adhered to the left side of the anastomosis, where the aortoenteric fistula had occurred. We believe that the graft dilatation was the cause of the anastomotic failure, although other factors such as atherosclerotic degeneration of the host aorta should also be considered. Knitted Dacron grafts that have been implanted for more than 10 years should therefore be monitored carefully because they have an inherent tendency to dilate, especially those manufactured before 1981.

Aged↗

PubMed1999

A novel selective nucleoside phosphorylating enzyme from Morganella morganii.

A selective nucleoside phosphorylating enzyme was purified to homogeneity from Morganella morganii NCIMB10466 crude extract. The enzyme appeared to consist of six subunits identical in molecular mass (M(r) 25,000). It phosphorylated various nucleosides at the 5'-position to produce nucleoside-5'-monophosphates using pyrophosphate as the phosphate source. Energy-rich compounds, such as carbamylphosphate and acetylphosphate, were also very effective phosphate donors. The enzyme also exhibited phosphatase activity, and dephosphorylated various phosphate esters, but had a weak effect on nucleoside-3'-monophosphates. Based on the results of the kinetic study, the enzyme appeared to be an acid phosphatase. Its activity was partly inhibited by sulfhydryl reagents and heavy metal ions, but not by chelating reagents such as EDTA. Using the purified enzyme, 32.6 mM 5'-IMP was synthesized from inosine with a 41% molar yield, but the synthesized 5'-IMP was hydrolyzed back to inosine and phosphate as the reaction time was extended.

Journal Article↗

PubMed1999

Nitrile hydratase involved in aldoxime metabolism from Rhodococcus sp. strain YH3-3 purification and characterization.

Nitrile hydratase responsible for aldoxime metabolism from the E-pyridine-3-aldoxime degrading bacterium, Rhodococcus sp. strain YH3-3 was purified and characterized. Addition of cobalt ion was necessary for the formation of enzyme. The enzyme activity was highly induced not only by nitriles and amides but also by several aldoxime compounds. The enzyme was purified approximately 108-fold with a 16% yield from the cell-free extract of the strain. The native enzyme had a Mr of approximately 130 000 and consisted of two subunits (alpha-subunit, 27 100; beta-subunit, 34 500). The enzyme contained approximately 2 mol cobalt per mol enzyme; it showed a maximum activity at 60 degrees C and at 40 degrees C under the rate assay and end-point assay conditions, respectively, and was stable over a wide range of pH (pH 2.5-11.0). The enzyme had a wide substrate specificity: it acted on aliphatic saturated and unsaturated as well as aromatic nitriles. The N-terminus of the beta-subunit showed good sequence similarities with those of other nitrile hydratases. Nitrile hydratase is part of the metabolic pathway for aldoximes in microorganisms.

Amino Acid Sequence↗