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Biomedical subjects

K Ohnishi

Publications and source records attributed to K Ohnishi.

At least 19 recordsLinked to original sources
PubMed1997

p53-dependent induction of WAF1 by a low-pH culture condition in human glioblastoma cells.

The effects of an acidic condition (pH 6.5) on WAF1 gene expression and p53 accumulation was investigated in human glioblastoma cells with different p53 statuses. WAF1 and p53 accumulation after treatment in acidic conditions was observed in A-172 cells carrying the wild-type p53 gene but not in T98G cells carrying the mutant p53 gene. Northern blot analysis showed that WAF1 gene activation by acidic conditions only occurred in A-172 cells. Consistent with this, activation of the binding of p53 to its specific DNA sequence by acidic stress was detected by gel mobility shift assay using p53 consensus sequence as a probe. Moreover, the increased WAF1 protein and mRNA levels that were due to acidic treatment returned to normal levels upon the return of the cells to neutral conditions, 6 h after the cells had been cultured in acidic conditions for 6 or 12 h. These findings suggest that WAF1 gene activation is inducible by acidic conditions in human glioblastoma cells, which is probably due to activation of the p53-dependent signal transduction pathway.

Cyclin-Dependent Kinase Inhibitor p21↗
PubMed1997

Transfection of p53-knockout mouse fibroblasts with wild-type p53 increases the thermosensitivity and stimulates apoptosis induced by heat stress.

PURPOSE: The relationship between the p53 functions and cellular thermosensitivity was evaluated using murine fibroblasts transfected with either wild-type p53 or mutated p53, or those with a null p53 genotype. METHODS AND MATERIALS: Cellular thermosensitivity was determined using the clonogenic assay. Cell cycle distribution was assayed by determining DNA content using flow cytometer. Apoptosis was analyzed by detection of both apoptotic bodies and DNA fragmentation. RESULTS: Stable transfectant with either wild-type p53 or mutated p53 was established. The transfectants with wild-type p53 were more thermosensitive than either those with a null p53 or with mutated p53. Although heat-induced G1 cell cycle arrest was substantially observed in all transfectants, wild-type p53 enhanced and prolonged the G1 arrest. Furthermore, wild-type p53 stimulated the induction of apoptosis by heat stress, whereas mutated p53 delayed it extremely. CONCLUSION: The p53 gene is at least a factor for determining cellular thermosensitivity and wild-type p53 contributes to thermosensitization resulting in enhancement of heat-induced apoptosis.

Animals↗
PubMed1997

Treatment with a new synthetic retinoid, Am80, of acute promyelocytic leukemia relapsed from complete remission induced by all-trans retinoic acid.

Differentiation therapy with all-trans retinoic acid (ATRA) has marked a major advance and become the first choice drug in the treatment of acute promyelocytic leukemia (APL). However, patients who relapse from ATRA-induced complete remission (CR) have difficulty in obtaining a second CR with a second course of ATRA therapy alone. We tested the efficacy of a new synthetic retinoid, Am80, in APL that had relapsed from CR induced by ATRA in a prospective multicenter study. Am80 is approximately 10 times more potent than ATRA as an in vitro differentiation inducer, is more stable to light, heat, and oxidation than ATRA, has a low affinity for cellular retinoic acid binding protein, and does not bind to retinoic acid receptor-gamma. Patients received Am80, 6 mg/m2, orally alone daily until CR. Of 24 evaluable patients, 14 (58%) achieved CR. The interval from the last ATRA therapy was not different between CR and failure cases. The clinical response was well correlated with the in vitro response to Am80 in patients examined. Adverse events included 1 retinoic acid syndrome, 1 hyperleukocytosis, 9 xerosis, 8 cheilitis, 16 hypertriglyceridemia, and 15 hypercholesterolemia, but generally milder than those of ATRA, which all patients had received previously. Am80 is effective in APL relapsed from ATRA-induced CR and deserves further trials, especially in combination with chemotherapy.

Adult↗
PubMed1997

Transfection of p53-knockout mouse fibroblasts with wild-type p53 increases the thermosensitivity and stimulates apoptosis induced by heat stress.

PURPOSE: The relationship between p53 functions and cellular thermosensitivity was evaluated using murine fibroblasts transfected with either wild-type p53 or mutated p53, or those with a null p53 genotype. METHODS AND MATERIALS: Cellular thermosensitivity was determined using the clonogenic assay. Cell cycle distribution was assayed by determining DNA content using flow cytometry. Apoptosis was analyzed by detection of both apoptotic bodies and DNA fragmentation. RESULTS: Stable transfectant with either wild-type p53 or mutated p53 was established. The transfectants with wild-type p53 were more thermosensitive than either those with a null p53 or with mutated p53. Although heat-induced G1 cell cycle arrest was substantially observed in all transfectants, wild-type p53 enhanced and prolonged the G1 arrest; furthermore, wild-type p53 stimulated the induction of apoptosis by heat stress, whereas mutated p53 delayed it extremely. CONCLUSION: The p53 gene is a factor for determining cellular thermosensitivity and wild-type p53 contributes to thermosensitization resulting in enhancement of heat-induced apoptosis.

Animals↗
PubMed1997

Exacerbated autoimmune hepatitis successfully treated with leukocytapheresis and bilirubin adsorption therapy.

A 58-year-old man with subacute fulminant onset of autoimmune hepatitis (AIH) was treated by leukocytapheresis (LCAP) and bilirubin adsorption therapy (BAT), rather than by administration of high-dose corticosteroids as he had mild glucose intolerance, and a definitive diagnosis of AIH was not obtained on admission; further, there was a risk of viral infection. After initiation of the therapies, serum transaminases and bilirubin, immunoglobulins, anti-nuclear antibodies, and rheumatoid factor decreased rapidly, as did the initially high levels of activated cells and several pro-inflammatory cytokines. Liver inflammation observed on liver biopsy settled during the course of the therapies, with no adverse side effects. A pause in the therapies was associated with deterioration; however, restoration of apheresis was followed by normalization. Remission was sustained throughout the period monitored, except for a recurrence 14 months after discharge, which was successfully resolved by two additional LCAP sessions. These results suggest that LCAP influences the causal mechanism(s) of exacerbation of AIH.

Adsorption↗
PubMed1997

Hyperthermia after cardiac surgery.

PURPOSE: To describe two cases of hyperthermia occurring after cardiac surgery. CLINICAL FEATURES: At the end of cardiopulmonary bypass, protamine was injected to reverse heparin. Following protamine, hypotension, pulmonary hypertension and hypoxia developed, but protamine induced hypotension recovered after administration of methyl predonisolone and catecholamines. Rectal temperature increased to 41 degrees C in the first case and 40 degrees C in the second after recovery from protamine induced hypotension. Arterial blood gas analysis, breathing 100% oxygen, showed severe acidosis and hypercapnia (pH 6.96, PaCO2 73 mmHg, PaO2 45 mmHg. BE -18 in the first case, and pH 7.13, PaCO2 59.9, PaO2 52.8, BE -11 in the second). At the same time, creatine phosphokinase levels showed 8400 u.L-1 in the first case and 4369 u.L-1 in the second. Serum and urine myoglobin concentrations were 334.2 ng.ml-1 and 1085 ng.ml-1, and 468 ng.ml-1 and 885 ng.ml-1, respectively. Efforts to cool the patients using alcohol were made. Following dantrolene (400 mg and 200 mg), the hyperthermia, acidosis, hypoxaemia and hypercarbia subsided (temperature 37.5 and 37.5 degrees C, PaO2 220 mmHg and 180 mmHg with 100% oxygen, PaCO2 35 mmHg and 41 mmHg respectively). Postoperatively, 20 mg.hr-1 dantrolene infusion were administered for 24 hr. In the first case, an anaphylactoid reaction was confirmed by increased plasma tryptase. CONCLUSION: We report two cases of hyperthermia after cardiac surgery in whom dantrolene was very effective in reducing the high rectal temperature.

Aged↗
PubMed1997

Effects of telencephalic ablation on short-term memory and attention in goldfish.

Two hypotheses regarding the functions of the teleost telencephalon (short-term memory and nonspecific arousal hypotheses) were examined by using a Y-maze training paradigm. A delayed reinforcement method, which allowed the separation of choice process (a process in which choice responses are evoked) and reward process (a process in which choice responses are reinforced), showed that normal fish can acquire clear learned responses to choice stimuli under different stimulus conditions between the choice process and the reward process, while telencephalon-ablated fish showed greatly impaired learning performance. Neither normal nor telencephalon-ablated fish could acquire learned responses to choice stimuli under neutral stimulus conditions in the reward process with respect to choice stimuli in the choice process. These results suggest that the telencephalon facilitates extratelencephalic short-term memory function essential for memory retention of choice stimuli and evoked choice responses until reinforcement, and support the supplementary function of the telencephalon suggested previously [Ohnishi, K., Telencephalic function implicated in food-reinforced colour discrimination learning in the goldfish, Physiol. Behav., 46 (1989) 707-712 and Savage, G.E., Temporal factors in avoidance learning in normal and forebrainless goldfish (Carassius auratus), Nature, 218 (1968) 1168-1169]. In addition, it was shown that cue information in the reward process is very important for the fixation of short-term memory of choice stimuli and choice responses. Furthermore, telencephalon-ablated fish also showed clear visual aspect selection, as did normal fish, when they were reinforced to a visual compound stimulus containing heterogeneous aspects (pattern and colour). This result shows that the telencephalon-related arousal or attentional function is not critical for aspect selection in goldfish. It seems that visual aspect selection in goldfish is performed without paying telencephalon-related 'selective attention' to an aspect.

Animals↗
PubMed1997

Assessment of myocardial distribution of retrograde and antegrade cardioplegic solution in the same patients.

OBJECTIVE: In order to clarify intramyocardial delivery and distribution of retrograde cardioplegic solution in humans, we induced both ante- and retrograde methods in the same patients to compare their respective delivery and distribution using myocardial contrast echocardiography during surgery. METHODS: 15 patients consisting of nine patients with valvular heart diseases and six patients with coronary artery diseases (including two patients with myocardial infarcted areas and two patients with areas supplied by coronary collateral situation associated with totally occluded coronary arteries without myocardial infarction). Induction of cardioplegia was initially accomplished antegradely and thereafter retrogradely. RESULTS: In valvular heart disease, retrograde cardioplegic solution was distributed less homogeneously, and was not delivered to the midportion of the interventricular septum in two-thirds of the patients (6/9). The transmural myocardial distribution in the anterior, lateral, and posterior walls in the left ventricle were similar for both ante- and retrograde cardioplegic solution, while delivery to the endocardial halves was better than to the epicardial halves (endo-/epicardial intensity ration in antegrade versus retrograde: 1.31 +/- 0.24 versus 1.29 +/- 0.26; 1.19 +/- 0.05 versus 1.36 +/- 0.23; 1.33 +/- 0.28 versus 1.44 +/- 0.35, respectively (all NS)). For delivery to the right ventricle, the existence of small cardiac vein was important. In patients with small cardiac vein (34% in our study), the delivery to the right ventricular dorsal walls was shown. In coronary heart disease, retrograde cardioplegic solution was well delivered to the areas by coronary collateral situation associated with totally occluded coronary arteries, but antegrade solution was not. Neither ante- nor retro grade solution was delivered to myocardial infarcted areas. CONCLUSIONS: These results have important implications for planning strategies for myocardial protection. We think that it is necessary to fully grasp the coronary arterial and venous anatomy of individual patients and to know how to use either ante- or retrograde cardioplegia properly.

Aged↗
PubMed1997

Low superoxide dismutase activity in schizophrenic patients with tardive dyskinesia.

BACKGROUND: Tardive dyskinesia (TD) is a therapy-resistant adverse effect of neuroleptics. Although the exact pathophysiology of TD is unknown, oxygen radicals have been speculated to play a role in TD based on several lines of evidence. Superoxide dismutase (SOD) is a key enzyme which scavenges oxygen radicals. The authors investigated the association between erythrocyte SOD activity and TD. METHODS: Erythrocyte SOD activities were measured, blinded as to the presence or absence of TD. In 30 patients with schizophrenia who had been on typical neuroleptics for more than 10 years. TD severity was independently assessed, using the abnormal involuntary movement scale (AIMS), by two raters. RESULTS: There was a significant decrease in erythrocyte SOD activity in the definite TD group (N = 10) as compared with the no TD (N = 8) and questionable TD (N = 12) groups. Erythrocyte Cu,Zn-SOD activities correlated with AIMS scores. CONCLUSIONS: Patients with TD had low SOD activities as compared to those without TD. As a causal link between SOD activity and TD was not established in this study, larger prospective studies are warranted to determine whether patients with low SOD activity are susceptible to neuroleptic-induced TD.

Adult↗
PubMed1997

Erythropoietin receptor expression on human bone marrow erythroid precursor cells by a newly-devised quantitative flow-cytometric assay.

In order to develop a non-isotopic quantitative assay of erythropoietin (Epo) receptor (EpoR) on human cells, we devised a flow-cytometric assay using cells stained with biotin-labelled and a streptavidine-RED670 conjugate. For quantification, we applied the Kolmogorov-Smirnov test and calculated the D value. The D value was evaluated from the degree of shift in two profiles according to the increase of fluorescence intensity due to the specific binding of biotin-labelled Epo to EpoR. A good correlation was observed between the number of EpoR calculated by 125I-Epo binding assay and the D value. Then, EpoR expression on bone marrow cells from normal individuals was studied by three-colour flow cytometry. In normal bone marrow, the number of EpoR on cells was highest in CD34+CD38 cells (approximately 1600 sites/cell), and decreased in the following order: CD34+CD38- cells > CD34+CD38+ cells > CD34-CD38+ cells. Glycophorin A (GpA) positive erythroid cells also expressed EpoR, and their CD34+ fraction expressed more EpoR than their CD34- fraction. However, the expression levels of EpoR of these fractions were lower than CD34+CD38- cells. These results indicated that EpoR was highly expressed on CD34+ haemopoietic progenitors from very early stages of differentiation without expression of CD38 antigen, and that the level of expression decreased with erythroid differentiation as well as with various lineage commitment in human bone marrow cells.

ADP-ribosyl Cyclase↗
PubMed1997

The FliO, FliP, FliQ, and FliR proteins of Salmonella typhimurium: putative components for flagellar assembly.

The flagellar genes fliO, fliP, fliQ, and fliR of Salmonella typhimurium are contiguous within the fliLMNOPQR operon. They are needed for flagellation but do not encode any known structural or regulatory components. They may be involved in flagellar protein export, which proceeds by a type III export pathway. The genes have been cloned and sequenced. The sequences predict proteins with molecular masses of 13,068, 26,755, 9,592, and 28,933 Da, respectively. All four gene products were identified experimentally; consistent with their high hydrophobic residue content, they segregated with the membrane fraction. From N-terminal amino acid sequence analysis, we conclude that fliO starts immediately after fliN rather than at a previously proposed site downstream. FliP existed in two forms, a 25-kDa form and a 23-kDa form. N-terminal amino acid analysis of the 23-kDa form demonstrated that it had undergone cleavage of a signal peptide--a rare process for prokaryotic cytoplasmic membrane proteins. Site-directed mutation at the cleavage site resulted in impaired processing, which reduced, but did not eliminate, complementation of a fliP mutant in swarm plate assays. A cloned fragment encoding the mature form of the protein could also complement the fliP mutant but did so even more poorly. Finally, when the first transmembrane span of MotA (a cytoplasmic membrane protein that does not undergo signal peptide cleavage) was fused to the mature form of FliP, the fusion protein complemented very weakly. Higher levels of synthesis of the mutant proteins greatly improved function. We conclude that, for insertion of FliP into the membrane, cleavage is important kinetically but not absolutely required.

Amino Acid Sequence↗
PubMed1997

Relapse in the external auditory canal of acute promyelocytic leukemia after treatment with all-trans retinoic acid.

A 54-year-old female was admitted to our hospital for gingival bleeding and was diagnosed as acute promyelocytic leukemia (APL). She received induction therapy according to the AML92 protocol of the Japan Adult Leukemia Study Group (JALSG) with all-trans retinoic acid (ATRA) plus chemotherapeutic agents. She achieved complete remission, but one year later had a relapse in her external auditory canal without leukemic cell in the bone marrow. Extramedullary disease is rare in APL. This case suggests the importance of careful observation for extramedullary relapse in patients who are treated with ATRA.

Agranulocytosis↗
PubMed1997

[Remission by leukocytapheresis for a patient with ulcerative colitis found refractory by conventional drug therapies].

A 40-year-old male was admitted to our hospital on August 30, 1994 to receive a new ulcerative colitis (UC) therapy, leukocytapheresis (LCAP). On the admission day, he had bloody stool 5 to 6 times/day, abdominal pain, slight fever, and hypoproteinemia. His UC type was moderately severe left-sided colitis with pseudopolyposis. Prior to admission to our hospital, his condition had not improved for about 9 months, despite drug therapies such as salicylazosulphapyridine, intravenous high dose prednisolone, protease inhibitor, intraarterial hydrocortisone sodium succinate, 4 series of pulse therapies with metylpredonisolone, enema of corticosteroid, azathioprine (Imuran), and cyclosporine at another hospital. Thus he was introduced to our college hospital and treated by LCAP since September 1. After 10 LCAP sessions, remission was observed and the patient discharged on December 23. Until he was later operated on for heavy bleeding after he had discontinued treatment and had drunk heavily, he had maintained remission for 13 months with LCAP only once a month even after we gradually decreased the other medical supports and stopped all of them. After LCAP, the normalization of high percentage of leukocytes presented HLADR+ and lymphocytes presented CD 11 a+ CD 8+ was also observed. This suggests LCAP intercepts the excess immune reaction in UC by removing leukocytes.

Adult↗
PubMed1997

Granulocyte colony-stimulating factor receptor at various differentiation stages of normal and leukemic hematopoietic cells.

Granulocyte colony-stimulating factor (G-CSF) is the most important cytokine in granulopoiesis, and induces the proliferation and differentiation of normal bone marrow granulocytic precursors. The physiologic effect of G-CSF is mediated through binding to specific cell surface receptors for G-CSF. Using a newly-devised quantitative flow-cytometric assay, we analyzed the expression of G-CSF receptors on normal and leukemic hematopoietic cells. In normal donors, G-CSF receptors are widely expressed from CD34-positive immature bone marrow cells to mature peripheral granulocytes. The highest expression of G-CSF receptors is observed in peripheral granulocytes. In the bone marrow, the level of G-CSF receptors expression increases in the following order; CD34+ CD33- cells < CD34+ CD33+ cells < CD34- CD33+ cells, indicating that G-CSF receptors are expressed on myeloid cells from a very early stage of differentiation and that the level of expression increases with the progress of cell maturation. G-CSF receptors are also detected on blast cells of patients with acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL). The number of cell surface receptors varies from patient to patient, and no clear correlation is observed between the expression of receptors and the leukemia subtype or the cell surface markers. In this respect, the clinical use of G-CSF should be carefully controlled in ALL as well as AML patients.

Antigens, CD↗
PubMed1997

[Leukocytapheresis for ulcerative colitis].

Major inclusion criteria for leukocytapheresis (LCAP) therapy were mainly insufficient response to conventional drugs therapy. LCAP was administered once a week for 5 weeks of intensive therapy and once approximately a month for maintenance therapy, for 38 patients with UC. LCAP could remove approximately 1 x 10(10) white blood cells in each session. In the evaluation, we classified the response to the LCAP as: 1) excellent, 2) moderately improved, 3) no change, and 4) deterioration. Clinical improvement was recognized in 29 of 38 patients (76%) including 8 with dramatic response during the intensive therapy, and continued throughout the maintenance therapy in 26 patients (68.4%). Even though their symptoms were mild, the patients with more than 5 years UC history seemed to be not effective. The patients with moderately improvement and with excellent response have kept remission for about 20 months and about 2.5 years on an average, respectively. Clinical and blood examinations showed no side effects in any cases. It suggests that LCAP is able to be a UC treatment between drug therapies and an operation.

Adult↗