PubMed Health⌕ Search

Biomedical subjects

Mayumi Mori

Publications and source records attributed to Mayumi Mori.

At least 19 recordsLinked to original sources
PubMed2006

Infrared predissociation spectroscopy of ammonia cluster cations (NH3)n+ (n=2-4) produced by vacuum-ultraviolet photoionization.

Infrared predissociation spectroscopy of vacuum ultraviolet-pumped ion (IRPDS-VUV-PI) is performed on ammonia cluster cations (NH3)n+ (n=2-4) that are produced by VUV photoionization in supersonic jets. The structures of (NH3)2+ and (NH3)4+ are determined through the observation of infrared spectra and vibrational calculations based on ab initio calculations at the MP2/6-31G** and 6-31++G** levels. (NH3)2+ is found to be of the "hydrogen-transferred" form having the (H3N+-...NH2) composition. In contrast, (NH3)4+ exhibits the "head-to-head" dimer cation (H3...NH3+ core structure, where the positive charge is shared between two ammonia molecules in the core, and two other molecules are hydrogen bonded onto the core. An unequivocal assignment of the infrared spectrum of (NH3)3+ has not been achieved, because the presence of two isomeric structures could be suggested by the observed spectrum and theoretical calculations.

Journal Article↗
PubMed2006

Antidipsogenic effects of a TRPV4 agonist, 4alpha-phorbol 12,13-didecanoate, injected into the cerebroventricle.

Transient receptor potential vanilloid 4 (TRPV4) is one member of the TRP superfamily of nonselective cation channels. Recently, the possibility has been raised that TRPV4 is an osmoreceptor, because it is found in the circumventricular organs where osmoreceptors are supposed to be distributed and because it is sensitive to osmotic pressure in in vitro experiments. In addition, TRPV4 knockout mice have abnormal osmosensitivity. In this study, effects of 4alpha-phorbol 12,13-didecanoate (4alpha-PDD), a TRPV4 agonist, on drinking behavior were examined to investigate roles for TRPV4 as an osmoreceptor in vivo in wild-type animals. Intracerebroventricular injections of 4alpha-PDD inhibited water intake under normal conditions in both light and dark periods of the day, after food deprivation, and after administration of angiotensin II. However, this drug did not influence increased water intake after administration of a hypertonic solution or after water deprivation that significantly increased plasma osmolality. Locomotor activity of the 4alpha-PDD-injected group decreased slightly compared with that of the vehicle-injected group; however, sweet taste, food intake, and body temperature were not different between the two groups. The antidipsogenic effects of 4alpha-PDD were blocked by preinjection into the ventricle of TRPV4 antagonists such as ruthenium red or gadolinium. These findings suggest that TRPV4 regulates drinking behavior under certain conditions, and the regulation interacts with the angiotensin II pathway.

Angiotensin II↗
PubMed2006

Treatment of acute myeloid leukemia patients aged more than 75 years: results of the E-AML-01 trial of the Japanese Elderly Leukemia and Lymphoma Study Group (JELLSG).

The feasibility and effects of combination chemotherapy for very elderly patients with acute myeloid leukemia was examined in 65 patients (including previous myelodysplastic syndrome) aged 76 years or morewith a performance status of 0 - 3. Induction chemotherapy was performed with 30 mg/m2 daunorubicin on days 1 - 3, 150 mg/m2 behenoyl cytosine arabinoside on days 1 - 7, and 70 mg/m2 6-mercaptopurine with 300 mg allopurinol taken orally on days 1 - 7 (BHAC-DM). The complete remission (CR) rate was 38.5%, whereas overall survival at 2 and 5 years was 22.0% and 4.7%, respectively. Two- and 5-year survival of CR patients was 41.8% and 11.2%, respectively. The relapse rate of the 25 CR patients was 64.0% and disease-free survival at 2 and 5 years was 21.0% and 11.2%, respectively. The therapy-related mortality rate at induction was 13.8%. BHAC-DM is feasible and effective for selected very elderly acute myeloid leukemia patients.

Aged↗
PubMed2006

Clinical features of polycythemia vera and essential thrombocythemia in Japan: retrospective analysis of a nationwide survey by the Japanese Elderly Leukemia and Lymphoma Study Group.

We conducted the first nationwide survey to clarify the clinical features, treatment methods, and prognoses for polycythemia vera (PV) and essential thrombocythemia (ET). A 1-page questionnaire was mailed to members of the Japanese Elderly Leukemia and Lymphoma Study Group (JELLSG). Surveys on 647 patients (PV, 266 patients; ET, 381 patients) were returned and analyzed. Thrombotic events at diagnosis and during follow-up occurred at rates of 15.4% and 8.5%, respectively, in PV cases and 17.6% and 8.7% in ET cases. Splenomegaly was observed in only 28.8% of PV patients and 10.8% of ET patients. The leukocyte alkaline phosphatase score was elevated in only 46.2% of PV patients. The incidences of abnormal karyotypes were less than 10% in both PV and ET cases. The rates of transformation to myelofibrosis were 2.6% in both PV and ET cases, and acute leukemia was noted in 1.1% of PV patients and 2.9% of ET patients. Prognostic factors were thrombotic history for PV and thrombotic history and age (>or=60 years) for ET. The present study clearly demonstrated clinical differences between Japanese and Western patients for PV and ET. Concerning the treatment of PV and ET, the study revealed considerable variation among Japanese hematologists. These results suggest the necessity of developing treatment guidelines according to risk stratification that are suitable for Japanese PV and ET patients.

Adolescent↗
PubMed2005

Capsaicin-induced, capsazepine-insensitive relaxation of the guinea-pig ileum.

The mechanisms underlying transient receptor potential vanilloid receptor type 1 (TRPV1)-independent relaxation elicited by capsaicin were studied by measuring isometric force and phosphorylation of 20-kDa regulatory light chain subunit of myosin (MLC(20)) in ileum longitudinal smooth muscles of guinea-pigs. In acetylcholine-stimulated tissues, capsaicin (1-100 microM) and resiniferatoxin (10 nM-1 microM) produced a concentration-dependent relaxation. The relaxant response was attenuated by 4-aminopyridine and high-KCl solution, but not by capsazepine, tetraethylammonium, Ba(2+), glibenclamide, charybdotoxin plus apamin nor antagonists of cannabinoid receptor type 1 and calcitonin-gene related peptide. A RhoA kinase inhibitor reduced the relaxant effect of capsaicin at 30 microM. Capsaicin and resiniferatoxin reduced acetylcholine- and caffeine-induced transient contractions in a Ca(2+)-free, EGTA solution. Capsaicin at 30 microM for 20 min did not alter basal levels of MLC(20) phosphorylation, but abolished an increase by acetylcholine in MLC(20) phosphorylation. It is suggested that the relaxant effect of capsaicin at concentrations used is not mediated by TRPV1, but by 4-aminopyridine-sensitive K(+) channels, and that capsaicin inhibits contractile mechanisms involving Ca(2+) release from intracellular storage sites. The relaxation could be explained by a decrease in phosphorylation of MLC(20).

4-Aminopyridine↗
PubMed2005

Long-term results of a multicenter randomized, comparative trial of modified CHOP versus THP-COP versus THP-COPE regimens in elderly patients with non-Hodgkin's lymphoma.

In treating elderly non-Hodgkin's lymphoma (NHL) patients, it is particularly important to use drugs that have a low incidence of adverse events and high efficacy. In this multicenter study, THP (pirarubicin)-COP (cyclophosphamide, vincristine, and prednisolone) was compared to two thirds dosage of full CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone) regimen with regard to both adverse events and efficacy. For a third group, etoposide (E) was added to the THP-COP regimen (THP-COPE) in order to achieve high dose-intensity. Subjects were 486 previously untreated patients, aged 65 or older (range, 65-92 years; median, 74 years), with NHL. Subjects were randomly assigned to receive THP-COP, two thirds CHOP, or THP-COPE. Four hundred and forty-three patients were assessed for response and followed for 8 years after the last subject registered. The complete remission rates for the THP-COP, CHOP, and THP-COPE groups were 42.5%, 41.4%, and 48.0%, respectively. There was no difference in overall survival or progression-free survival among these 3 groups. In aggressive lymphoma, there was also no difference in complete response (CR) rate (45.3% in THP-COP, 44.9% in CHOP, 48.0% in THP-COPE), overall survival, and progression-free survival among these groups. The 5- and 8-year survival rates for all patients were 29.4% and 18.7%, respectively. The 5- and 8-year survival rates for patients with aggressive lymphoma were 27.4% and 17.4%, respectively. Although long-term survival for patients with aggressive lymphoma on our regimens was not worse compared to previous reports, the CR rate was lower. Because severe adverse events were not observed, higher dose chemotherapy may be directed to achieve better CR rates. In patients with T-cell-type lymphoma, the CR rate was greater after treatment with THP-COP (51.4%) or THP-COPE (57.7%) compared to treatment with CHOP (19.4%). Pirarubicin may be more useful for T-cell lymphoma than doxorubicin. Because adverse cardiac events were reported only in CHOP, adverse cardiac events might be low in the THP group.

Aged↗
PubMed2004

Mechanisms underlying anorexia after microinjection of bombesin into the lateral cerebroventricle.

Intracerebroventricular (i.c.v.) injections of bombesin (BN) and gastrin-releasing peptide (GRP) dose-dependently decreased food intake in male Wistar rats fasted for 17 h. Neuromedin B (NMB) did not show any effect on food intake. After BN administration, locomotor activity did not significantly change, compared with a vehicle-injected group. The anorexia induced by BN (0.3 microg) was perfectly inhibited by pretreatment with a GRP-receptor antagonist, [D-Tyr(6)]BN(6-13) methyl ester (10 microg), an NO synthase inhibitor, L-nitro-arginine (30 microg), and a PKG inhibitor, H-9 (2 microg). The cGMP concentration in the hypothalamus increased 1 h after administration when compared with the vehicle-injected group. On the other hand, an NMB-receptor antagonist, BIM23127 (10 microg), and the protein kinase (PK) C inhibitors, chelerythrine (2 microg) and Go6983 (2 microg), inhibited only the late phase of the anorexia. A PKC activator, phorbol 12, 13-dibutyrate (3 microg), injected into the ventricle decreased food intake. These findings suggest that BN suppresses food intake mainly mediated through the GRP receptor and NO-cGMP-PKG pathway, and NMB receptor and PKC is partly involved in the late phase of the anorexia.

Animals↗
PubMed2004

Vanadate activates Rho A translocation in association with contracting effects in ileal longitudinal smooth muscle of guinea pig.

We characterized the effects of vanadate, an inhibitor of tyrosine phosphatase, on the tension, the level of myosin light chain (MLC) phosphorylation, and Rho A activation in intact ileal longitudinal smooth muscle of the guinea pig to study the role of tyrosine phosphorylation in contraction signaling. Vanadate exerted a sustained contraction with a slow onset of tension development, in a concentration-dependent manner. The contractile effects of vanadate were accompanied by increases in the level of MLC phosphorylation. The tyrosine kinase inhibitor genistein; the MLC kinase inhibitor 1-(5-chloronaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine hydrochloride (ML-9); and the Rho kinase inhibitor (+)-(R)-trans-4-(1-aminoethyl)-N-(4-pyridyl) cyclohexanecarboxamide dihydrochloride, monohydrate (Y-27632) inhibited the vanadate-induced contraction and MLC phosphorylation. Vanadate caused Rho A translocation from the cytosol to the membrane fraction, which was inhibited by genistein, but not by ML-9 and Y-27632. These data indicate that vanadate induces Rho A activation probably via protein tyrosine phosphorylation and the subsequent contraction through increases in the level of MLC phosphorylation.

Animals↗
PubMed2004

Characterization of capsaicin-induced, capsazepine-insensitive relaxation of ileal smooth muscle of rats.

The mechanisms underlying the capsaicin-induced relaxation of the acetylcholine- as well as KCl-contraction were studied by measuring isometric force and phosphorylation of 20-kDa regulatory light chain subunit of myosin (MLC(20)) in ileal longitudinal smooth muscles of rats. Capsaicin relaxed acetylcholine- and KCl-stimulated preparations in a concentration-dependent manner; the former was less sensitive to capsaicin than the latter and maximum responses to capsaicin (a percentage of papaverine-induced relaxation) were 70.6+/-7.5%, n=10 and 97.1+/-0.9%, n=13, P<0.05, respectively. The response showed no desensitization. Like nifedipine, capsaicin relaxed the tissue precontracted with an agonist of L-type Ca(2+) channels as well. The relaxant effect of capsaicin was not inhibited by capsazepine (a selective antagonist of vanilloid VR1 receptors), nitro-l-arginine, indomethacin, guanethidine, nor by inhibitors of soluble guanylate cyclase. Capsaicin inhibited acetylcholine-induced transient contraction in a Ca(2+)-free, EGTA solution. Phosphorylation of MLC(20) (a percentage of phosphorylated to total MLC(20)) was increased 1 min after application of 10 microM acetylcholine (7.8+/-2.0%, n=6 vs. 22.6+/-3.2%, n=6) and of 65.9 mM KCl (2.2+/-0.3%, n=8 vs. 10.7+/-1.7%, n=12). Capsaicin reduced the KCl-induced increase more markedly than acetylcholine-induced increase in MLC(20) phosphorylation. When the tissue was contracted for 20 min with acetylcholine, MLC(20) phosphorylation was increased, and capsaicin reduced markedly the contraction and abolished MLC(20) phosphorylation both elicited by acetylcholine. It is suggested that capsaicin relaxes the rat ileum via its direct action on smooth muscle, and that capsaicin inhibits contractile mechanisms involving extracellular Ca(2+) influx via non-L-type Ca(2+) channels, possibly via store-operated Ca(2+) channels and Ca(2+) release from intracellular storage sites. The effects of capsaicin on acetylcholine- and KCl-induced contraction could be explained by a decrease in MLC(20) phosphorylation.

Acetylcholine↗
PubMed2004

[Mantle cell lymphoma markedly infiltrated into adrenal glands with adrenal insufficiency].

A 66-year-old male was admitted to our hospital complaining of bilateral hypochondrial pain, back pain and loss of weight in May, 2002. Superficial lymph nodes were not palpable on admission. The leukocyte count was 3430/microl, hemoglobin concentration, 13.0g/dl, and platelet count, 174000/microl. LDH, soluble IL-2 receptor, ACTH and cortisol values were out of the normal range (LDH 1368IU/l, sIL-2R 2630U/ml, ACTH 132pg/ml, cortisol 7.4microg/dl). Abdominal CT scan showed bilateral adrenal masses, and abnormal uptake of Ga-scintigraphy was seen correspondent with the bilateral adrenal masses. The histological diagnosis of bilateral adrenal masses cannot be performed because of the bleeding tendency, but atypical cells were observed in the patient's bone marrow aspirate. Surface marker analysis of atypical cells showed CD5+, cyclin D1+, CD19+, CD20+ and HLA-DR+. From these results we diagnosed this case as a mantle cell lymphoma (stage IV B) markedly infiltrated into the adrenal glands with adrenal insufficiency. The bilateral adrenal masses dramatically reduced in size after CHOP chemotherapy with hydrocortisone supplementation. We report on the present case and summarize the reports of adrenal grand-infiltrating lymphomas.

Adrenal Gland Neoplasms↗
PubMed2004

[Survey on the threshold for platelet transfusions].

We carried out a survey on platelet transfusions performed in nine general hospitals. We evaluated 303 adults who received a total of 24455 units over 1864 platelet transfusions. The underlying diseases were hematologic disorders with chemotherapy (59.7%), hematologic disorders without chemotherapy (15.5%), hematopoietic stem cell transplantation (18.5%), and others (2.0%). The patient platelet count before transfusion (platelet trigger value) was measured in only 77.1%. The platelet trigger value differed greatly between the hospitals, with an average of 2.2 x 10(4)/microl, a minimum of 1.3 x 10(4)/microl, and maximum of 3.2 x 10(4)/microl. Only 55.3% of the platelet transfusions carried out complied with the Platelet Transfusion Guideline published by the Ministry of Health, Labour and Welfare. The hospitals surveyed could be divided into those who gave mainly around 10 units and those who gave over 10 units. The total dose of platelets transfused was more in the hospitals that used mainly 15 or more unit-PCs than in the hospitals that used mainly 10 unit-PCs. These results indicate that platelet transfusion may be greatly reduced by complying with the 2 x 10(4)/microl of platelet transfusion threshold and by selecting less than 10 units of PC per transfusion.

Data Collection↗
PubMed2004

[Painless myocardial ischemia during the treadmill test in the elderly].

PURPOSE: Myocardial infarction without chest pain occurs in high incidence in elderly. However, the pathophysiological significance of the silent ischemia is still unknown. To elucidate the significance of the "painless" symptom during myocardial ischemia induced by exercise, we analyzed the incidence of silent ischemia on treadmill tests and attempted to examine the severity of the coronary stenosis in such painless subjects. METHOD AND RESULTS: Treadmill test was conducted on 580 patients aged 65 to 92 years (man: 261, woman: 319) with suspected myocardial ischemia. One hundred and seventy-nine patients (man: 89, woman: 90) showed positive results. Among them 126 patients (70%) did not complain of chest pain (painless group) during treadmill tests of these. Forty four patients showed dyspnea and 82 patients did not have any symptoms during the tests. The incidence of painless ischemia tended to increase in women (77%) over men (62%) (p=0.02). The incidence of diabetes in the painless group did not differed from that in the group of patients with chest pain. Coronary angiography was conducted on 79 patients (31: chest pain group, 15: painless group with dyspnea, 33: painless group without dyspnea). Coronary artery stenosis more than 75% were observed in 25 (80%), 13 (86%) and 24 (73%) patients respectively, suggesting chest pain itself did not mean the existence of severe coronary disease. CONCLUSION: Painless ischemia during the treadmill test was found in high incidence in the elderly. Painless ischemia must be treated as same as ischemia with chest pain.

Age Factors↗
PubMed2003

Pharmacological characteristics of bombesin receptor mediating hypothermia in the central nervous system of rats.

Bombesin (BN) and structurally related peptides, gastrin-releasing peptide (GRP) and neuromedin B (NMB), injected into the lateral ventricle produce multiple effects such as hypothermia, anorexia and hormone release. In this study, the pharmacological characteristics of BN receptors mediating hypothermia in the central nervous system (CNS) were investigated using free-moving male Wistar rats. Intracerebroventricular injections of BN, GRP and NMB produced hypothermia in a dose-dependent manner. The BN (0.3 microg)-induced effect showed a short latency and a 4-h duration with a potency increased by more than 100 times compared to the NMB-induced effect. Pretreatment with [D-Tyr(6)]BN(6-13)methylester, a GRP receptor antagonist, inhibited the BN (0.3 microg)- and NMB (7 microg)-induced hypothermia. On the other hand, BIM23127, an NMB receptor antagonist, did not influence the hypothermia. Of the protein kinase C (PKC) inhibitors, chelerythrine, Go6983, staurosporine and GF109203X, the first two partially blocked the BN-induced hypothermia. A PKC activator, phorbol-12,13-dibutyrate, decreased the rectal temperature. Genistein (a tyrosine kinase inhibitor), Y-27632 (a Rho kinase inhibitor) and PD98059 (a MAPK inhibitor) tended to suppress the BN-induced hypothermia, however, these were not significant. The inhibitory effect of a mixture of the three inhibitors, chelerythrine, genistein and Y-27632, on the BN-induced hypothermia was of a similar degree to that of chelerythrine alone. The BN receptor mediating the hypothermia seem to be the GRP subtype, and the effect involves activation of PKC.

Animals↗
PubMed2003

Mechanisms underlying the hydrogen peroxide-induced, endothelium-independent relaxation of the norepinephrine-contraction in guinea-pig aorta.

The mechanisms underlying the hydrogen peroxide-induced relaxation of the norepinephrine-contraction were studied by measuring isometric force, myosin light chain (MLC(20)) phosphorylation and cyclic GMP in endothelium-denuded muscle from the guinea-pig aorta. Norepinephrine (5.2+/-1.3 microM) produced a phasic, followed by a tonic contraction. Hydrogen peroxide (10 and 100 microM), glyceryl trinitrate (30 and 300 nM) and 8-bromo cyclic GMP (30 and 100 microM) did not change the basal tone, but reduced the norepinephrine-induced contraction. Phosphorylation of MLC(20) (percentage of phosphorylated to total MLC(20)) was increased 1 min (5.9+/-1.0% vs. 35.9+/-4.9%) and, to a lesser extent, 20 min (3.7+/-1.7% vs. 13.9+/-1.6%) after the addition of norepinephrine. Hydrogen peroxide (100 microM) did not modify basal MLC(20) phosphorylation, but reduced the increase in MLC(20) phosphorylation induced by 1-min exposure to norepinephrine (20.9+/-4.1%). Its effect was abolished by catalase. When the tissue was incubated for 20 min with norepinephrine in the presence of hydrogen peroxide, norepinephrine-induced MLC(20) phosphorylation was not changed (13.6+/-1.5%), as compared to that in the absence of hydrogen peroxide. Hydrogen peroxide relaxed norepinephrine-stimulated aortas in a concentration-dependent fashion with EC(50) values of 5.9+/-0.2 microM. The relaxation was inhibited by soluble guanylate cyclase inhibitors and increased by an inhibitor of cyclic GMP-selective phosphodiesterase. In aorta precontracted with norepinephrine, hydrogen peroxide (100 microM) relaxed the tissue by 89+/-11% and almost doubled tissue concentrations of cyclic GMP, whereas sodium nitroprusside (1 microM) relaxed the tissue by 100% and increased cyclic GMP concentrations 30-fold. It is suggested that the inhibitory effects of hydrogen peroxide on the norepinephrine-induced phasic and sustained contractions are explained by a decrease in MLC(20) phosphorylation and by an alteration in MLC(20) phosphorylation-independent mechanisms, respectively. The effects of hydrogen peroxide were in part mediated by cyclic GMP.

Animals↗
PubMed2003

Paraoxonase1 polymorphism Leu-Met55 is associated with cerebral infarction in Japanese population.

BACKGROUND: Paraoxonase1 (PON1) is HDL-associated ester hydrolase which has been shown to prevent LDL and HDL oxidation in vitro. PON1-coding region has two common polymorphisms (M/L55 and A/B192) that influence PON activity. We examined whether these polymorphisms relates with the incidence of cerebral infarction (CI) which is one of the major atherosclerotic disease in Japan. MATERIAL/METHODS: The study population was comprised of 112 unrelated Japanese CI patients and 106 healthy Japanese individuals. The PON1 genotypes were determined by PCR and digestion by specific restriction enzymes. RESULTS: PON1-192 polymorphism revealed no significant difference of genotype and allelic distribution in CI patients and controls. Frequency of L/M alleles in PON1-55 polymorphism (0.88, 0.12, respectively) was different from previously reported frequencies in Caucasians. Comparison of allelic distribution of the PON1-55 polymorphism showed a significant increase of the M allele in CI subjects compared with control subjects. All three subjects with the MM genotype were in the CI group. Of subjects with an AA genotype, the frequencies of the MM and LM genotypes were significantly higher and that of the LL genotype was significantly lower in the CI group compared with the control group. Frequency of the M allele in the CI group was significantly higher in subjects who had the AA genotype. CONCLUSIONS: These findings suggest that the enzyme might be involved in the development of atherosclerosis of cerebral arteries. Moreover, this finding might indicates that the genetic markers in Japanese linked to distinct genetic event from Caucasians.

Adult↗
PubMed2003

[Free/total prostate specific antigen ratio (%PSA) to predict probability of prostate cancer].

It has been reported recently that %PSA, the ratio of free-PSA(F-PSA) and total-PSA(T-PSA), remains significantly lower in sera of patients with prostatic cancer(PCA) than there in cases with benign prostate hypertrophy(BPH). We examined %PSA can be used for differential diagnosis of PCA from BPH. Forty-seven non-treated Japanese patients with prostate problem were examined for PSA assays and biopsy. On biopsy, 25 cases were diagnosed as PCA, and 22 cases as BPH. On T-PSA value, there were 18 cases of PCA and 8 cases of BPH whose T-PSA values were over 10 ng/ml. When %PSA was studied, cases with less than 15% of %PSA were found to be PCA exclusively(16/16), while cases with less than 20 of %PSA included 19 PCAs and 4 BPHs. In 17 PCA patients with stage B to stage D, the %PSA was less than 20 except one case. T-PSA was examined in 88 cases at the checkup in our old age home. Four samples of which T-PAS levels were in gray zone, were assayed for %PSA. Two of them, with %PSA values less than 20 ng/ml, were found to be PCA, while the remaining two, with %PSA over 20 ng/ml, were BPH.

Aged↗