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Biomedical subjects

A Miura

Publications and source records attributed to A Miura.

At least 19 recordsLinked to original sources
PubMed1992

Short-term modulation of cerebellar Purkinje cell activity after spontaneous climbing fiber input.

1. There are two opposite points of view concerning the way climbing fiber input in a Purkinje cell modifies simple spike (SS) activity transiently: depression versus enhancement of SS activity. The different groups of investigators favored one effect predominating over the other. In the decerebrate unanesthetized cat, we recorded spontaneous activity of single Purkinje cells and investigated time course of SS activity after the complex spike (CS). 2. In the peri-CS time histogram, there was a SS pause lasting, on average, 10.8 ms after onset of the CS in all of the 316 cells recorded. The pause was followed by a rapid increase in SS activity to a maximum, which was on average 175.6% of a pre-CS control level, and a gradual return to around the control level in the majority of the cells recorded (pause-facilitation type, 71.2%). The increase in SS activity was significant (P < 0.01, t test) during 20-100 ms. The SS activity during the 20-100 ms was, on average, 163.7% of the control level. In some cells (pure-pause type, 25.3%), no significant changes were found (P > 0.01) in the post-pause SS firing. In contrast, only 3.5% of the cells (pause-reduction type) showed a significant (P < 0.01) firing decrease (average 54.0% of the control level) lasting 20-60 ms after the pause period. 3. Analysis of the pre-CS time histogram revealed no significant differences (P > 0.01) in the SS activity between pre-CS periods in all of the cells recorded, suggesting that the SS activity enhancement is not due to a coactivated mossy fiber input just preceding the activation of the climbing fiber input. 4. Analysis of the raster diagram revealed variability of individual SS responses after the CS. The probability of occurrence of the increase in SS number during a post-CS period of 0-100 ms with respect to that during a pre-CS period of -100-0 ms in individual raster traces was high (on average 78.2%), medium (57.3%), and low (36.3%) in the pause-facilitation, pure-pause, and pause-reduction types of the cell, respectively. 5. Nonsequential time histograms showing frequency distribution of the pause duration after the CS in individual raster traces and that showing interspike intervals of the SS were constructed.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

[Clinical evaluation of effects of KRN8601 (rhG-CSF) on neutropenia].

Clinical effects of KRN8601 (recombinant human granulocyte colony-stimulating factor:rhG-CSF) were studied in 26 patients with chronic neutropenia including 4 Kostmann's disease, 1 Shwachman's syndrome, 1 Lonsdale's syndrome, 1 glycogen storage disease Ib-associated, 6 chronic benign, 5 chronic hypoplastic, 2 cyclic, 4 autoimmune and 2 miscellaneous neutropenia. The patients were given rhG-CSF intravenously at doses of 20-540 micrograms/m2 or subcutaneously at doses 20-400 micrograms/m2, over the periods of 2-32 weeks. Increases in neutrophil counts occurred after rhG-CSF administration in 23 of the 26 patients. Patients with Kostmann's disease, Shwachman's syndrome and chronic hypoplastic neutropenia responded poorly compared to patients with other types of neutropenia. There were no serious side effects which caused interruption of the study. These results indicated a beneficial effect of KRN8601 in various types of chronic neutropenia.

Adolescent↗
PubMed1992

[Renal and electrolyte disturbances in chronic myelogenous leukemia].

Renal and electrolyte disturbances in 91 patients with chronic myelogenous leukemia (CML) were analyzed over a period of these twenty years. At diagnosis, renal and electrolytes were studied in 72 patients including 65 in chronic cases, 5 in accelerated phase and 2 in blastic crisis. There were 8 cases of hypocalcemia among 62 patients and 5 cases of hyperphosphatemia among 48 patients. The cases of hyperphosphatemia and renal dysfunction had short median survival. There were no significant differences of renal and electrolyte disturbances between before and after chemotherapy. Various electrolyte disturbances, that is, hyponatremia, hypo-, hyperkalemia, hypocalcemia, hypo-, hyperphosphatemia, were found in the blastic crisis of CML. In the last admission, renal dysfunction and various electrolyte disturbances were present in almost half of the cases. Pathological studies were performed in 18 autopsy cases. Acute tubular insufficiency or necrosis, hypercalcemic nephropathy, and renal infiltration of leukemic cells were recognized in patients who had renal dysfunction.

Adolescent↗
PubMed1992

[B-cell chronic lymphocytic leukemia complicated by autoimmune thrombocytopenic purpura].

A 74-year-old Japanese male was admitted because of anemia. Hepatosplenomegaly, lymphoadenopathy, and purpura were not found. The laboratory data on admission revealed that the white-cell count was 9,400/microliters, the hemoglobin 11.1 g/dl, and the platelet count 17,000/microliters. Platelet-associated IgG was 794.2 ng/10(7) cells. The patient was diagnosed as having autoimmune thrombocytopenic purpura (ATP) at this time. He was treated with prednisolone, but his thrombocytopenia not improve. In addition to prednisolone, azathioprine was given to him. During the course of treatment, leukocytosis gradually appeared and the white-cell count reached more than 30,000/microliters with over 70% lymphocytes. A bone marrow aspiration revealed 70% of small lymphocytes, and surface marker analysis showed that CD19 and HLA-DR were positive on these lymphocytes. Southern blotting analysis demonstrated rearrangements of JH and JK. He was finally diagnosed as B-CLL complicated by ATP. One month after the azathioprine administration, the platelet count increased more than 30,000/microliters and the white-cell count decreased less than 10,000/microliters. About 2% of patients with CLL are known to be complicated by ATP. To our knowledge, the present case is the first case of B-CLL complicated by ATP in Japan.

Aged↗
PubMed1991

T cell-mediated inhibition of erythropoiesis in aplastic anaemia: the possible role of IFN-gamma and TNF-alpha.

The inhibitory activity of T cells on autologous erythroid colony-forming units (CFU-E) (T cell inhibitory activity) in patients with aplastic anaemia (AA) was investigated. In 11 (32.4%) out of 34 AA cases, T cell inhibition on autologous CFU-E growth was greater than that in normal individuals. In order to evaluate the mechanism of this inhibitory activity, T cell surface markers, interferon (IFN) production in peripheral blood mononuclear cell (PBMNC) liquid culture, and cytokine levels such as IFN and tumour necrosis factor-alpha (TNF-alpha) in CFU-E clot cocultured with T cells, were measured in a portion of the patients. In five patients investigated for IFN production in PBMNC liquid culture, all produced statistically more IFN activity than normal individuals under phytohaemagglutinin (PHA-P) stimulation (P less than 0.01) with no relation to T cell inhibitory activity. In only one patient whose T cells displayed increased CD8 and HLA-DR antigen (CD8+HLA-DR+) and inhibitory activity, a significant amount of IFN-gamma was observed in CFU-E clot cocultured with T cells, and the addition of anti-IFN-gamma antibody to the coculture resulted in recovered CFU-E colony growth. These results suggest that IFN-gamma production by T cells may explain, at least in part, the pathogenesis of haematopoietic defects in AA. In other patients however, T cell inhibitory activity neither correlated to the T cell subpopulations (CD4+/CD8+, CD8+HLA-DR+), IFN production in PBMNC liquid culture, nor to IFN and TNF-alpha levels in CFU-E clot culture. The roles played by cytokines other than IFN and TNF-alpha on haematopoietic precursor cells require further evaluation in a larger sample of patients with AA.

Adolescent↗
PubMed1991

Hematopoietic recovery in a patient with acute lymphoblastic leukemia after an autologous marrow graft purged by combined hyperthermia and interferon in vitro.

We describe a patient with acute lymphoblastic leukemia (ALL) in whom hemopoiesis recovered after an autologous marrow graft purged by in vitro hyperthermia. A 17-year-old woman was diagnosed as having ALL in April 1985. After clinical remission was induced, marrow cells were harvested. The marrow cells were treated with hyperthermia at 42.0 degrees C for 1 h in the presence of alpha-interferon to eliminate residual leukemic cells, and then cryopreserved. In January 1990, during her fourth remission she was treated with busulfan and cyclophosphamide, and then received the thawed autologous marrow. Her hematopoietic recovery was prompt with normal trilineage regeneration without any life-threatening complications. She is in good health without evidence of a leukemic relapse at 6 months after autologous bone marrow transplantation. This case suggests that human multilineage progenitor cells retain self-renewal capacity in vivo even after treatment with heat and alpha-interferon in vitro followed by the freezing and thawing procedures.

Adolescent↗
PubMed1990

A molluscan neuropeptide related to the crustacean hormone, RPCH.

A peptide that potentiates twitch contraction of the radula retractor muscle of the prosobranch mollusc Fusinus ferrugineus was isolated from the ganglia of the animal. Its primary structure is H-Ala-Pro-Gly-Trp-NH2 (APGWamide) closely related to the C-terminal tetrapeptide of the crustacean red-pigment-concentrating hormone. APGWamide showed modulatory actions on contractions in various molluscan muscles.

Amino Acid Sequence↗
PubMed1990

Movements of the large intestine in the anuran larvae, Xenopus laevis.

1. The contractile behavior of the large intestine of Xenopus laevis tadpoles was studied. 2. The large intestine is divided into a colon and rectum, and shows three types of movements: rhythmic ascending (antiperistaltic) waves of contraction originating at the anal end of the large bowel, rhythmic longitudinal contractions in the rectum and colon, and irregular contractions. The first two patterns occur in the large bowel in situ and thus appear mature. The last one occurred only in older preparations, and thus appeared pathological. 3. Antiperistaltic waves of contractions and longitudinal contractions are generated independent of each other, suggesting that circular muscles and longitudinal muscles contract separately. 4. Acetylcholine, adrenaline and noradrenaline augment motility. 5. The premetamorphic motility of the large bowel is similar to that seen in adult frogs. Comparable motility was not observed elsewhere in the larval alimentary tract. The large intestine appears to be the first portion of the anuran alimentary tract to acquire the adult physiological and morphological profile.

Acetylcholine↗
PubMed1990

[Pharmacological studies of celiprolol: I. Beta-blocking effect, intrinsic sympathomimetic activity, vasodilating and hypotensive effects].

The beta-blocking effect, intrinsic sympathomimetic activity (ISA), and vasodilating and hypotensive effects of celiprolol were tested. 1. Celiprolol competitively antagonized the isoproterenol-induced positive chronotropic and inotropic effects in guinea pig right atrial and papillary muscles and isoproterenol-induced guinea pig tracheal relaxation with pA2 values of 8.03, 7.98 and 6.43, respectively. 2. In dogs, isoproterenol-induced increases in cardiac contractility and heart rate were markedly inhibited by celiprolol (83.1 and 84.8%, respectively), while isoproterenol-induced hypotension was suppressed only by 16.8%. 3. Celiprolol increased the beating rate of the right atrium and relaxed the trachea isolated from normal and reserpinized guinea pigs. Celiprolol also potentiated the contractility of the left atrium isolated from reserpinized animals. These effects of celiprolol were antagonized by propranolol. 4. Celiprolol concentration-dependently relaxed rat femoral arteries contracted by methoxamine. The concentration-relaxation curve was shifted to the right by pretreatment with propranolol. 5. Orally administered celiprolol produced long lasting hypotension in conscious SHR without any heart rate change. 6. These results indicate that celiprolol is a highly cardioselective beta-blocker with a significant ISA, which contributes to its vasodilatory and hypotensive effects.

Adrenergic beta-Antagonists↗
PubMed1990

[Pharmacological studies of celiprolol: II. Alpha 2-Adrenoceptor blocking effects of a cardioselective beta-blocker, celiprolol].

alpha-Adrenoceptor blocking effects of the cardioselective beta-blocker celiprolol were tested. 1. Celiprolol antagonized the contractions induced by UK-14304, but not those by phenylephrine, in isolated rat tail arteries with a pA2 value of 4.95. 2. In the isolated rat vas deferens, twitch contractions elicited by the transmural electrical stimulation (TS) were almost blocked by TTX (10(-7) M). Clonidine inhibited the TTX-sensitive contraction in a concentration-dependent manner. Celiprolol produced little effect on the inhibitory effects of clonidine. The concentration-inhibition curve of clonidine was shifted to the right by yohimbine (10(-8) M), but not by prazosin (10(-8) M). 3. Although celiprolol slightly increased the 3H-efflux to TS from the [3H]-norepinephrine-loaded rat vas deferens, the increment was not significant. Yohimbine (10(-7) M) significantly increased the 3H-efflux. TTX (10(-7) M) and bretylium (3 x 10(-5) M) blocked the 3H-efflux. 4. In the spinal rat treated with propranolol (3 mg/kg, i.v.) and prazosin (0.1 mg/kg, i.v.), celiprolol (30 and 100 mg/kg, i.v.) and yohimbine (0.1-1 mg/kg, i.v.) inhibited the pressor response to clonidine. 5. These results indicate that celiprolol may have a weak alpha 2-blocking effect which was more effective on postsynaptic alpha 2-receptors than presynaptic ones.

Adrenergic alpha-Antagonists↗
PubMed1990

[Pharmacological studies of celiprolol: III. Effects of celiprolol on the cardiovascular system and renal function, and its antiarrhythmic effects].

Effects of celiprolol on the cardiovascular system and renal function, and its antiarrhythmic effects were studied. 1. In anesthetized dogs, celiprolol (0.01-3 mg/kg, i.v.) dose-dependently depressed the maximum rate of rise of left ventricular pressure, cardiac output and cardiac work less severely than propranolol and atenolol. 2. Celiprolol (0.01 mg/kg, i.v.) decreased the myocardial oxygen consumption in anesthetized dogs as potently as propranolol. 3. Celiprolol (0.03-3 mg/kg, i.v.) tended to increase femoral blood flow. Celiprolol (1 mg/kg, i.v.) increased common carotid blood flow. 4. Celiprolol decreased urine volume and urinary excretion of Na+ and Cl- at doses of 1 and 10 mg/kg and increased the sodium reabsorption rate at a dose of 10 mg/kg in anesthetized dogs, whereas it produced no change in plasma renin activity. 5. Celiprolol inhibited both halothane-adrenaline arrhythmia in dogs and ouabain-induced arrhythmia in rabbits. Its antiarrhythmic effects were 1/10-1/3 as potent as those of propranolol. 6. Celiprolol suppressed the maximum rate of rise of action potential at a concentration of 3 x 10(-4) M, which was 30 times as high as that of propranolol. Celiprolol (3 x 10(-5)-3 x 10(-4) M) dose-dependently shortened the effective refractory period (ERP), but it produced no change in the ratio of ERP to action potential duration. 7. These results suggest that celiprolol may be a useful drug for the treatment of ischemic heart disease and some types of arrhythmia, and that it has only a little influence on renal function.

Action Potentials↗
PubMed1990

[Pure red cell aplasia induced by B19 parvovirus during allogeneic bone marrow transplantation].

We report a patient who had abrupt onset of pure red cell aplasia (PRCA) induced by B19 parvovirus during allogeneic bone marrow transplantation (BMT). A 14-year-old girl with APL in complete remission was admitted in February 1988, for the purpose of BMT. She was received marrow from HLA identical sister on March 17, 1988 (day 0). She received 120 mg/kg cyclophosphamide and 12 Gy total body irradiation for conditioning of BMT. For graft-versus-host disease (GVHD) prophylaxis she was given cyclosporine and short term methotrexate. She did not develop acute GVHD after BMT, but on the day 28 a bone-marrow aspirate revealed findings of PRCA. During this course the number of white blood cell and platelet favorably recovered. B 19 parvovirus DNA was detected in the serum of the day 30 and day 42. Antihuman B 19 parvovirus (HPV) antibody titers were increased: the values of anti-HPV IgM were suddenly elevated and those of anti-HPV IgG were elevated. Serum on the day 42 inhibited erythroid progenitors (CFU-E, BFU-E) but not inhibited myeloid progenitors (CFU-C). A reticulocyte count recovered on the day 50. As the patient was HPV-IgG negative prior to BMT and the donor was HPV-IgG seronegative, the source of infection may be platelet transfusion (day 7 through 14).

Adolescent↗
PubMed1990

[Angio-immunoblastic lymphadenopathy with fibrosis of bone marrow, lymph node, liver and spleen, and proliferation of epithelioid cells in lymph nodes].

We report a 47-year-old man diagnosed as angio-immunoblastic lymphadenopathy with dysproteinemia (AILD) with fibrosis of the bone marrow, lymph node, liver and spleen, and proliferation of epithelioid cells in lymph node. He was admitted to a hospital in May, 1980 because of general fatigue, cough, fever and systemic lymphadenopathy. The diagnosis of AILD was based on a biopsy of right cervical lymph node. His symptoms were improved but recurred with the addition of icterus and progressive pancytopenia with decrement of prednisolone. He was referred to our hospital in July, 1980 and his physical examination revealed generalized lymphadenopathy, icterus and hepatosplenomegaly. Hemogram showed pancytopenia, and needle biopsy of the bone marrow disclosed fibrosis. Sections from the lymph node showed AILD with proliferation of epithelioid cells. Administration of 60 mg/day of prednisolone improved the fever, lymphadenopathy and hepatosplenomegaly. However he died suddenly of acute respiratory failure on July 30. Autopsy showed fibrosis of bone marrow, lymph node, liver and spleen with infiltration of abnormal lymphocytes, and pulmonary aspergillosis.

Cell Division↗
PubMed1990

[The frequency of patients with positive HIV-antibody in the various groups and the prognosis of these patients treated with SNMC].

Among 300 patients receiving blood and/or blood products because of blood disorders, 3 (1%) were positive for HIV by ELISA. However, 3 patients were thought to be false positive because they had received bolus injection of gamma-globulin and their serum became negative after 6 months. Moreover, no viral inclusion or HIV-antigen was detected. In 30 patients with hemophilia and related disorders, 21 (70%) were positive by ELISA, Immunofluorescence, Passive-agglutination and Western Blot method. Immunodeficiency, as reflected by decreases of CD 4/8 ratio and NK activity, was successfully treated with high-dose of Stronger Neo-Minophagen C.

Adolescent↗