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Biomedical subjects

Y Masaki

Publications and source records attributed to Y Masaki.

At least 19 recordsLinked to original sources
PubMed2005

Neuroprotective effect of mivazerol, an alpha 2-agonist, after transient forebrain ischemia in rats.

BACKGROUND: We examined whether mivazerol, an alpha2-agonist, had neuroprotective effects after transient forebrain ischemia in rats. METHODS: Male Sprague-Dawley rats, anesthetized with halothane, were assigned to one of four groups (n=10 each): control (C, normal saline) and mivazerol 10 microg/kg (M10), 20 microg/kg (M20) and 40 microg/kg (M40) groups. Thirty minutes after drug administration, forebrain ischemia was induced with hemorrhagic hypotension and bilateral carotid artery occlusion for 10 min, and then the brain was reperfused. The neurologic outcome was evaluated 24 h, 48 h and 7 days after ischemia, followed by histologic evaluation. RESULTS: The survival rate during 7 days was significantly lower in group M40 than in groups M10 and M20 (P<0.05). The neurologic outcome was significantly better in groups M10 and M20 than in group M40 7 days after ischemia (P<0.05). The number of intact neurons in hippocampal CA1 was significantly greater in group M20 than in the other groups (P<0.05). Neuronal injury in the neocortex was significantly less in group M20 than in groups C and M40 (P<0.05). CONCLUSIONS: Our results suggest that mivazerol, up to 20 microg/kg, provides neuroprotective effects, whereas 40 microg/kg may exaggerate neuronal injury after transient forebrain ischemia in rats.

Adrenergic alpha-Agonists↗
PubMed2004

Quantitative analysis of amoA mRNA expression as a new biomarker of ammonia oxidation activities in a complex microbial community.

AIMS: To quantitatively analyse the changes to amoA mRNA (ammonia mono-oxygenase encoding mRNA) profiles in response to a change in ammonia oxidation activity in a complex microbial community. METHODS AND RESULTS: The amoA mRNA levels in both a batch-mode incubation and a continuously fed nitrification reactor were determined by real-time reverse transcription-PCR analysis. The amoA mRNA level changed rapidly in response to the change in environmental conditions which affect ammonia oxidation activity. CONCLUSION: An increase in amoA mRNA level can be detected within 1-2 h in response to an initiation of cell activity whereas a decrease in amoA mRNA level is detected within 24 h in response to a cessation of activity. SIGNIFICANCE AND IMPACT OF THE STUDY: amoA mRNA, which shows sensitive response to ammonia oxidation activity, can be used as a biomarker of ammonia oxidation activity in wastewater treatment processes where many bacterial species exist.

Ammonia↗
PubMed2001

Oxidative transformation of arylmethyl bromides and alcohols with a combination of mesoporous silica FSM-16 and alkali iodides under photoirradiation.

[reaction: see text]. A mesoporous silica FSM-16 was found to be a selective and recyclable promoter for the oxidative dehalogenation of arylmethyl bromides to provide the corresponding alcohols and for the oxidation of arylmethyl alcohols to provide the corresponding aldehydes with a combination of alkali iodides and solvents under photoirradiation conditions.

Journal Article↗
PubMed2001

Synthesis and photodynamic activity of a cationic zinc monoazaporphyrin bearing a nitrogen atom at the peripheral position.

A new cationic monoazaporphyrin, zinc 2-aza-8,12,13,17-tetraethyl-2,3,7,18-tetramethylporphyrinium iodide 3 was synthesized. Photodynamic activity of 3 in degradation of 2',3'-isopropylideneguanosine 4 was compared with 2-aza-8,12,13,17-tetraethyl-3,7,18-trimethylporphyrin 1, zinc 2-aza-8,12,13,17-tetraethyl-3,7,18-trimethylporphyrin 2, and hematoporphyrin 5. The quarternary ammonium 3 showed a remarkable increase of photodynamic activity compared with 5, although no appreciable difference in the activity was observed between 1 and 5.

Aza Compounds↗
PubMed2001

T-Cell type acute lymphoblastic leukemia following cyclosporin A therapy for aplastic anemia.

Cyclosporin A (CsA) is used to prevent rejection in transplantation and to treat autoimmune and hematologic diseases such as aplastic anemia. However, the tumor growth-promoting effect of CsA remains controversial. We report the case of a 24-year-old man who developed acute lymphoblastic leukemia of precursor-T-cell origin after 75 months of treatment with CsA for aplastic anemia. The surface antigen phenotype of his leukemic cells was CD2+, CD3+, CD5+, CD7+, CD4-, CD8-, CD10-, CD20-, CD34-, CD41-, and CD56-. Southern blot analysis revealed a monoclonal rearrangement of T-cell receptor-Jgamma nongermline fragments in HindIII digestion.

Adolescent↗
PubMed2001

Granulocytic sarcoma of megakaryoblastic differentiation in the lymph nodes terminating as acute megakaryoblastic leukemia in a case of chronic idiopathic myelofibrosis persisting for 16 years.

A 43-yr-old Japanese woman presented with mild anemia, leukocytosis and splenomegaly in May 1984. Splenomegaly and anemia gradually progressed. Sixteen years later, in October 2000, she developed inguinal lymphadenopathy. Biopsy of the lymph node revealed infiltration of blasts, megakaryocytes, fibroblasts and myeloid cells. Large blasts with basophilic cytoplasm with cytoplasmic projections appeared in the peripheral blood. These blasts were negative in peroxidase stain, positive in acid phosphatase and weakly positive in periodic acid-Schiff stain. Immunohistochemical staining with monoclonal antibodies revealed that these blasts were positive with anti-CD41 (glycoprotein IIb/IIIa) and negative with other monoclonal antibodies. So diagnosis of granulocytic sarcoma in megakaryoblastic transformation from chronic idiopathic myelofibrosis was made. A cytogenetic study revealed that bone marrow cells were 46,XX del(13)(q?) initially and additional abnormalities including der(5,5,11)(q11;q13)ins(5;?)(q11;?) were found when she developed megakaryoblastic transformation. Granulocytic sarcoma of megakaryoblastic transformation from chronic idiopathic myelofibrosis is a rare event. Immunophenotyping with monoclonal antibody for CD41(glycoprotein IIb/IIIa) confirmed the diagnosis.

Cell Differentiation↗
PubMed2001

1,6-Asymmetric induction during the conjugate addition of arylcopper reagents to a chiral sulfinyl-substituted pyrrolyl alpha,beta-unsaturated amide.

The asymmetric conjugate addition of arylcopper reagents derived from aryl Grignard reagents and copper(I) iodide to a chiral 1-[2-(p-tolylsulfinyl)]pyrrolyl cinnamide proceeded smoothly to give (3R)-adducts with high diastereoselectivities (> or =92% de) in high yields. Conjugate additions either of the cinnamide with the alkyl Grignard reagent-copper(l) iodide combination or of the crotonamide derivative with aryl Grignard reagent-copper(l) iodide gave moderate to good diastereoselectivities. With these sulfinyl pyrrolyl alpha,beta-unsaturated amides, the chiral auxiliary was efficiently recovered without any loss of optical purity after asymmetric conjugate addition.

Chromatography, High Pressure Liquid↗
PubMed2001

[Marginal zone lymphoma associated with Sjögren's syndrome and hepatitis C virus infection].

A 64-year-old female was admitted in May 1997, because of salivary gland swelling. Histology of the right parotid gland revealed malignant lymphoma, diffuse medium-sized B-cell type, and she was treated with local radiotherapy and chemotherapy. She was rehospitalized in April 1998, because of recurrence of lymphoma in the stomach and the sigmoid colon. She had splenomegaly and lymphadenopathy (neck and inguinal). Laboratory findings revealed marked elevation of rheumatoid factor and RNA of hepatitis C virus. A diagnosis of Sjogren's syndrome was made by dryness and the histological findings of labial biopsy. Marginal zone B-cell lymphoma mainly consisted of centrocyte-like cells and lymphoepithelial lesions, and CD 20 and IgM-kappa were positive with immunohistochemical staining. Lymphoma involved the gut and spleen. We discuss the correlation of malignant lymphoma with Sjogren's syndrome and HCV infection.

Antigens, CD20↗
PubMed2001

[A study on cervical reflex induced by click stimuli in cats].

UNLABELLED: The effects of click stimuli on the cervical muscle have been wildly studied, but no information is available on what reaction click stimuli elicit from the cervical cord. We studied the effects of click stimuli on the cervical cord in cats. PURPOSE: To determine the response of the cervical cord to click stimuli in cats. MATERIALS AND METHODS: Subjects were ten adult cats confirmed to have normal tympanic membranes. Cats were placed on artificial ventilation by tracheal incision. Auditory brainstem response (ABR) of both ears was measured to determine its threshold. Following the cervical incision, the dorsal vertebrae were removed, the cervical cord was exposed at C3 to C6, and bipolar needle electrodes were inserted. The reference electrode was attached to the forehead. Click stimuli were presented using 1-20 Hz clicks. RESULTS: Responses peaking at 4.89-5.10 ms were induced by click stimuli of 105 dBSPL (1 Hz) at C3. Latencies tended to be prolonged with decreasing sound pressure. No response was confirmed at of C4 to C6. The responses to clicks of 20 Hz or more disappeared when 100 responses were summed. After the experiment, we confirmed that accessory nerves showed a response to electrical stimuli applied by bipolar needle electrodes. The cervical cord was removed to make sure that the electrode had been passed into the spinal nucleus of the accessory nerve. DISCUSSION: Spinal nuclei of accessory nerves exist at C3 to C5 of the cervical cord, and are associated with the movement of the sternocleidomastoid muscle at C3 in particular. Click stimuli are reported to affect the sternocleidomastoid muscle. The results of our study appear to reflect the response of the spinal nucleus of the accessory nerve to click stimuli. The fact that responses to clicks of 20 Hz or more disappeared when 100 responses were summed suggests that the response was induced via a pathway other than the auditory pathway.

Acoustic Stimulation↗
PubMed2001

[A case of Sjögren's syndrome with dermatomyositis who died of rapidly progressive interstitial pneumonia].

We report a case of 55 year-old woman with six year history of Sjögren's syndrome developed fatal rapidly progressive interstitial pneumonia. She had been well until February 1999. She developed swelling and erythematous lesions in the cheek and hands in spring 1999. She was admitted to our hospital for investigations of skin lesions in May 1999. Physical examination on admission revealed small hemorrhagic lesions in the nailfold. Serum CK level was slightly elevated. Electromyogram and MRI suggested mild myositis in the proximal upper extremities. She was suspected to have dermatomyositis along with Sjögren's syndrome. Prednisolone 10 mg/day had been given for her skin problems since March 1999. Suddenly, dyspnea on exertion was appeared on 34th day of admission. Chest X-ray film showed an acute worsening of interstitial pneumonia. Methylprednisolone pulse therapy (1000 mg for 3 days) and cyclophosphamide pulse therapy (500 mg for a day) were started, and she was subsequently treated with 60 mg/day of prednisolone and 250 mg/day of Cyclosporin A. However, interstitial pneumonia did not respond to the treatment, and pneumomediastinum and pneumothorax have developed. She died of respiratory failure on 55th day. We consider that most likely explanation for fatal interstitial pneumonia is concomitantly occurred dermatomyositis.

Cyclophosphamide↗
PubMed2001

Investigation of coronary artery bypass grafting for a patient with myelodysplastic syndrome.

A 79-year-old male with unstable angina, who had myelodysplastic syndrome (MDS), was treated with coronary artery bypass grafting (CABG). MDS causes refractory anemia accompanied by various degrees of granulocytopenia and thrombocytopenia. Pancytopenia caused by MDS may complicate patients with major infections and bleeding during cardiac surgery. There were very few patients with MDS who had undergone open-heart surgery. Three case studies, including this study, had reported successful cases of CABG in patients with MDS and the analogous diseases of MDS. We used granulocyte colony-stimulating factor (G-CSF), red blood cells (RBCs) and platelets transfusions in peri-operative state. We did not need a large amount of transfusion of RBCs and platelets in intra-operative and postoperative states. We had prevented major bleeding and severe wound infections in the acute postoperative state.

Aged↗
PubMed2000

Cloning and expression of a novel human antibody-antigen pair associated with Felty's syndrome.

An increasing number of studies suggest the importance of antibodies in the pathogenesis of most systemic and organ-specific autoimmune diseases, although there is considerable controversy over the precise role of the autoantibodies involved. In humans, a major obstacle to progress is the identification and cloning of the relevant autoantibodies and autoantigens. Here, an approach based on the sequential use of antibody phage display and antigen expression libraries is developed and applied to a donor suffering from rheumatoid arthritis (RA), splenomegaly, and peripheral destruction of neutrophils leading to neutropenia (Felty's syndrome). An antibody phage display library was constructed from bone marrow from the donor and a high-affinity human mAb, ANA15, selected by panning against fresh neutrophils and independently by panning against a fixed cell line. The antibody showed strong staining of neutrophils and a number of cell lines. Probing of a lambdagt11 expression library from an induced myelomonocytic cell line with the mAb ANA15 identified the eukaryotic elongation factor 1A-1 (eEF1A-1) as a novel autoantigen. The specificity of ANA15 was confirmed by reactivity with both purified and recombinant eEF1A-1. Screening of a large panel of sera revealed that 66% of patients with Felty's syndrome had elevated levels of anti-eEF1A-1 antibodies. The cloning of this antibody-antigen pair should permit rational evaluation of any pathogenicity resulting from the interaction and its significance in neutropenia.

Antigen-Antibody Complex↗
PubMed2000

S-Methylisothiourea sulfate improves renal, but not hepatic dysfunction in canine endotoxic shock model.

OBJECTIVE: Excess production of nitric oxide (NO) by inducible NO synthase (iNOS) has been implicated in the pathophysiology of septic shock. This study was designed to see whether S-methylisothiourea sulfate (SMT), a selective inhibitor for iNOS, prevents cardiovascular changes and multiple organ damage in the canine endotoxic shock model. DESIGN: Prospective, comparable, experimental study. SETTING: Laboratory at a university hospital. SUBJECTS: Twenty male mongrel dogs were studied under pentobarbital anesthesia. INTERVENTIONS: Dogs were divided into three groups: bacterial lipopolysaccharide (LPS) group (n = 7) receiving continuous infusion of LPS (2 mg/kg/h for 1 h); LPS plus SMT group (n = 7) receiving LPS and SMT (1 mg/kg, bolus i. v., followed by continuous infusion of 1 mg/kg/h for 1 h); and vehicle plus SMT group (n = 6). MEASUREMENTS AND RESULTS: Hemodynamics, blood gas parameters, and urine output were measured during 6 h observation periods. Serum levels of lactate, transaminases, and bilirubin were measured at baseline, 1 and 6 h. Creatinine and free water clearance, urine sodium excretion and fractional excretion of sodium were calculated. LPS caused a profound hypotension associated with decreases in cardiac output and oxygen delivery, lactic acidosis, renal and liver dysfunction, and thrombocytopenia. SMT prevented the LPS-induced hypotension and renal dysfunction, whereas it did not affect the LPS-induced decreases in cardiac output or oxygen delivery, hyperlactatemia, liver dysfunction, or thrombocytopenia. SMT alone had no appreciable effects on hemodynamics, blood gases, liver or renal functions. CONCLUSIONS: These findings show that SMT improves renal, but not hepatic dysfunction, in dogs with endotoxic shock, suggesting that iNOS-derived NO plays differential roles in sepsis-associated multiple organ dysfunction.

Animals↗