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Biomedical subjects

A Shibata

Publications and source records attributed to A Shibata.

At least 181 records · Page 10Linked to original sources
PubMed1995

[Persistent discrepancy between FDP and D-dimer in a patient with acute leukemia].

In a patient with acute myeloblastic leukemia, serum fibrinogen/fibrin degradation products (FDP) were markedly elevated to 54.91 micrograms/ml, but plasma D-dimer was only slightly elevated (1.44 micrograms/ml). FDP in plasma measured by a method using monoclonal antibody specific to FDP was less than 5 micrograms/ml. Gradual reduction of blastic cells was obtained with the therapy of low-dose cytarabine, G-CSF and etoposide. The serum FDP increased up to 71.74 micrograms/ml accompanied with a transient elevation of D-dimer, and subsequently declined without any anticoagulant therapy. However, a discrepancy between serum FDP and plasma D-dimer lasted for a long time. In this case persistent acceleration of coagulation and fibrinolysis which may result in the elevation of serum FDP was not observed, suggesting that the greater part of increased FDP didn't reflect the true FDP formed by plasmin. There were possibilities that elevated serum FDP values were also caused by the presence of soluble fibrin, unclottable fibrinogen and the degradation products by nonplasmic proteinases. Simultaneous measurements of FDP and D-dimer are useful for a more accurate evaluation of hyperfibrinolytic states and to avoid possible misinterpretations due to falsely positive FDP.

Aged↗
PubMed1995

[Essential thrombocythemia in transformation to smouldering megakaryoblastic leukemia with myelofibrosis].

Leukemic transformation in essential thrombocythemia (ET) is rare. We describe a patient with ET which transformed to megakaryoblastic leukemia with myelofibrosis after treatment with melphalan for 8 years. His course after transformation smouldered for 20 months without antileukemic chemotherapy. A 61-year-old man was referred by a local doctor to Niigata University Hospital due to nasal bleeding in June 1984. Complete blood count (CBC) was as follows; hemoglobin 12.4 g/dl, platelets 268.8 x 10(4)/microliters, and white blood cells 11,900/microliters, with differentials of 39% PMN, 1% basophils, 2% eosinophils, 4% monocytes, and 13% lymphocytes. Bone marrow examination revealed hyperplasia of megakaryocytes without increase of reticulin fibers. Neutrophil alkaline phosphatase activity and karyotype of marrow cells were normal. ET was diagnosed. He was followed up by local doctor. The platelet count was controlled at a level of approximately 40 x 10(4)/microliters with melphalan for eight years. In January 1992 he developed pain in his lower extremities. He was admitted to our hospital on May 29, 1992. CBC was as follows; hemoglobin 8.9 g/dl, platelets 14.3 x 10(4)/microliters, and white blood cells 3,500/microliters, with differentials of 25% PMN, 5% monocytes, 28% lymphocytes, and 24% blasts. Bone marrow aspiration was unsuccessful and bone marrow biopsy revealed increases in fibroblasts and collagen fibers. Circulating blasts were positive for CD4, CD7, CD25, CD13, CD33, CD34, and HLA-DR and partly positive for CD41 and CD36. In ultrastructural cytochemistry blasts were positive for platelet peroxidase but negative for myeloperoxidase. Cytogenetic study revealed 46, XY, +der (1) t(1:7) (p11;q11) in all of five metaphases. He was diagnosed with megakaryoblastic leukemia accompanied by myelofibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Demonstrations of de-and remineralization mechanism as revealed in synthetic auditory ossicle (Apaceram) of rats by laser-Raman spectrometry.

In investigations of the process of bone destruction caused by chronic otitis media complicated with cholesteatoma, we proposed previously a hypothesis to explain its mechanism. In the present study, we substitute a synthetic auditory ossicle (Apaceram) for the bone to simplify the model system of experiments for our hypothesis. Its process was studied on a model simulation in vitro, in vivo and clinically at molecular level, using laser-Raman spectrometry. An increase of conductivity in both the saline solution and double-distilled water immersed Apaceram indicated demineralization depending on time lapse. The process of demineralization was revealed by the Raman spectral profiles as shown by narrowing a half-peak breadth (p < 0.01) of v1 signal (PO4(3-), 960 cm-1) and the disappearance of the shoulder at circa 950 cm-1 on the Apaceram surface implanted for 6 months. On the other hand, the process of remineralization was revealed in vivo by the spectral profiles: 1) a broader half-peak breadth (p < 0.01) of v1 signal on the Apaceram surface implanted for 10 months than that implanted for 6 months; 2) a weak reappearance of the shoulder at ca. 950 cm-1 on the Apaceram surface after 10 months; 3) four signals (v1 through v4) of PO4(3-) on the HOAP observed for inside the Apaceram shaft and 4) a weak v1 signal on both the granular fluorescent substance in the clinical case and the high density area of subcutaneous tissue after contact with the Apaceram in rats for 3 months. Judging from these investigations, it is proposed that the mechanism of bone destruction associated with cholesteatoma is a form of de- and remineralization.

Animals↗
PubMed1994

A prospective study of pancreatic cancer in the elderly.

Risk factors for pancreatic cancer were examined in a cohort study of 13,979 residents of a retirement community. After 9 years of follow-up, 65 incident cases of pancreatic cancer were identified. An increased risk of pancreatic cancer was associated with a history of diabetes and cholecystectomy. Higher intake of vegetables, fruits, dietary beta-carotene, and vitamin C were each associated with a reduced risk of pancreatic cancer, although none of these associations was statistically significant. Risk of pancreatic cancer decreased with increasing tea consumption but was unrelated to coffee consumption. No strong or consistent association was seen between either smoking or alcohol consumption and risk of pancreatic cancer, but a consistent and significant increase in risk followed cholecystectomy.

Aged↗
PubMed1994

Significant stabilization of the phosphatidylcholine bilayer structure by incorporation of small amounts of cardiolipin.

The effects of the negatively charged phospholipid cardiolipin on the structural properties of egg-yolk phosphatidylcholine (EyPC) liposomal membranes were studied by monitoring the water permeability of the liposomes caused by osmotic shrinkage in hypertonic glucose solution. Incorporation of small amounts of bovine heart cardiolipin (BhCL) into the EyPC membranes caused a significant decrease in their water permeability associated with stabilization of the membrane structure. Much evidence obtained by attenuated total reflection IR spectroscopy suggested that incorporation of BhCL into the EyPC membranes causes a cooperative conformational change in the EyPC polar head groups, but does not alter the fluidity of the bilayer structure in the fluid liquid crystalline state. Incorporation of small amounts of BhCL stabilized the intermolecular hydrogen-bonded network including water molecules of the hydration layers at the bilayer surface that are important for the stable bilayer configuration of the EyPC molecules. The antisymmetric PO2- frequencies of the EyPC membrane with incorporated BhCL suggested that the BhCL content of 50 mol% induced a change in the phase behaviors of mixed BhCL/EyPC membranes.

Animals↗
PubMed1994

Tissue factor in plasma of patients with disseminated intravascular coagulation.

Recently it has been shown that tissue factor (TF), an important trigger for initiating blood coagulation, is present in the circulating plasma. In order to assess the clinical implications of TF in plasma, plasma concentration of TF was quantitated in 65 patients with disseminated intravascular coagulation (DIC). The mean concentration of plasma TF was elevated in patients with DIC at presentation as compared with healthy subjects (446 +/- SD 536 pg/ml vs. 138 +/- 51 pg/ml, P < 0.001). Abnormally high levels were found only in 46.2% of the patients, predominantly in patients with non-hematological solid tumors and acute leukemia. Plasma TF did not correlate with hemostatic markers of DIC such as thrombin-antithrombin III complex, prothrombin fragment 1 + 2, plasma-alpha 2-plasmin inhibitor complex, FDP, D-dimer, or fibrinogen. Serial determinations of plasma TF demonstrated that plasma TF changes roughly in parallel with the course of DIC in most patients with elevated TF at presentation of DIC. These findings suggest that plasma TF is potentially valuable for monitoring the progress of DIC in a limited population of patients.

Disseminated Intravascular Coagulation↗
PubMed1994

Clustered lipid droplets in the endomyocardial biopsies from a patient with neuroleptic malignant syndrome.

Neuroleptic malignant syndrome is caused by serious adverse effects of antipsychotic agents and occurs only rarely. Endomyocardial biopsies documented unique clustered lipid droplets in a Japanese man with this disease. After administration of haloperidol, he had symptoms of high fever, respiratory dysfunction, and cardiogenic shock, and subsequently suffered from multiple organ failure. Fortunately, he was completely cured with intensive therapy. In the convulsant stage, left ventricular endomyocardial biopsies were performed that yielded the interesting discovery of unique clustered lipid droplets among the myofibrils. It was suggested that although the pathomechanism of neuroleptic malignant syndrome is unknown, this disease may be characterized by a lipid metabolic disorder of the cardiac muscle cell.

Biopsy↗
PubMed1994

Risk factors of fatality in motor vehicle traffic accidents.

The present study was conducted to evaluate the effect of potential risk factors--such as driving without a license, alcohol use, speed, seat belt, and helmet--use on fatality in motor vehicle traffic accidents. Unconditional multiple logistic regression analysis was employed to take these factors and age into account, simultaneously. The effect of driving without a license was not significant after controlling for other factors. The deleterious effect of alcohol use remained significant for male motorcar drivers after controlling for speed and seat belt use. Magnitude of the risk due to speed was slightly reduced after controlling for alcohol use and seat belt use, but the striking effect remained highly significant. Speed was the strongest risk factor of fatality for both motorcycles and motorcars and for both sexes and seemed to be more critical for motorcyclists than motorcar drivers. The protective effect of seat belt use was unchanged after adjustment for alcohol and speed, and the effectiveness of seat belt use was demonstrated for motorcar drivers. The effectiveness of helmet use for male motorcyclists was dependent upon speed at the time of the accidents, suggesting an interaction between helmet use and speed. Helmet use was definitely protective at a low speed of < or = 50 km/h, but ineffective at high speeds of over 50 km/h.

Accidents, Traffic↗
PubMed1994

Leukemic cell membrane from acute myelogenous leukemias with massive mast cell infiltration has a mast cell differentiation activity under culture condition containing interleukin 3.

Five cases of acute myelogenous leukemia with massive mast cell infiltration in bone marrow and leukemic tumors of the soft tissue were examined to elucidate the relationship between leukemic cells and mast cells. Leukemic cells in each case showed no basophil/mast cell features and differentiated to neutrophil-like cells in liquid culture. Isolated mast cells failed to proliferate with or without growth factors used irrespective of culture conditions. Mononuclear cell fraction obtained from all patients gave rise to relatively numerous mast cells in interphase culture using IL-3 but not in other culture systems. The simultaneous addition of leukemic cell membrane and IL-3 or delayed addition of leukemic cell membrane produced more numerous and mature mast cells in the upper layer of interphase culture using IL-3. However, addition of leukemic cell membrane alone failed to increase the number of mast cells. Similar results were obtain using mononuclear cells obtained from volunteers and cord blood cells. These results indicate that a cell to cell contact or interstitial substance together with IL-3 are essential requirements for growth and maturation of mast cell precursors and that the cell membrane itself in some cases of leukemia has the ability to induce maturation of mast cell precursors.

Adolescent↗
PubMed1994

Characterization of newly established adriamycin resistant human leukemic cell lines (KY-ADR1 and KY-ADR2).

New adriamycin (ADR) resistant human leukemic cell lines (KY-ADR1 and KY-ADR2) have been established. KY-ADR1 was selected from a cytosine arabinoside (Ara C) resistant cell line by gradually increasing the concentration of ADR and KY-ADR2 from the parental cell line, KY-821, by the same method. The IC50s of both cell lines were 4.3 x 10(-5) and 3.6 x 10(-5) M ADR, respectively. Both lines revealed a similar cross resistance to various anticancer drugs, but KY-ADR1 was resistant to Ara C, whereas KY-ADR2 was sensitive. MDR1 gene was over-expressed and P-glycoprotein was expressed on the cytoplasmic membrane in both lines. Neither verapamil nor cyclosporin A could completely reverse ADR resistance. In addition, no significant changes in topoisomerase II and glutathione-s-transferase levels were detected. These findings indicate that ADR resistance in both cell lines is mainly mediated by P-glycoprotein and some other mechanism may be present. Interestingly, growth of both cell lines was stimulated by natural IL-1 and not affected by TNF alpha and IFN gamma, whereas growth of parental KY-821 was inhibited by these factors. These cell lines will provide new biological aspects on drug resistant leukemic cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

The unique and shared properties of neuronal growth cones that enable navigation and specific pathfinding.

The neuronal growth cone has as one of its primary functions the role of guiding the elongating neurite to its appropriate target. The events during pathfinding require that the neuronal growth cone responds to particular molecules in the environment by making appropriate changes in the behavior of the growth cone. This paper discusses the role of intracellular calcium as a signalling system mediating these responses. The specific roles of the growth cone filopodia in acting as antennae in advance of the motile growth cone are discussed in the context of calcium mediated pathfinding events.

Animals↗
PubMed1994

Mutational spectrum in the p53 gene in bladder tumors from the endemic area of black foot disease in Taiwan.

An elevated risk of bladder cancer has been reported in the endemic region of 'black foot disease' on the southwest coast of Taiwan and may be related to high arsenic levels in artesian well water. Thirteen urothelial tumors from this endemic region were examined for mutations in exons 5-8 of the p53 gene to identify the effects of possible exogenous factors at the DNA level. DNA was extracted from archival tissue after microdissection of tumors and analyzed by PCR-SSCP (polymerase chain reaction-based single strand conformation polymorphism), followed by direct sequencing. Eight cases (62%) showed mutations and 9 of the 10 point mutations observed were transitions. The type and position of the mutations were not significantly different when compared with the spectra of p53 mutations previously reported for transitional cell carcinomas (TCCs). However, two of the mutations were CGC-->CAC base changes at codon 175, a mutational hotspot for many tumor types but previously unreported in TCCs except in cases associated with inflammatory agents. Three of the tumors examined were found to contain double mutations, a relatively rare mutagenic event in human cancers. Our results suggest that the agents responsible for the high risk of bladder cancer in the black foot disease region may operate through an inflammation-based mechanism which increases the amount of DNA damage per mutagenic event.

Adult↗
PubMed1994

Anti-alpha beta T cell receptor antibody prevents the progression of experimental autoimmune myocarditis.

We investigated the effects of anti-alpha beta T cell receptor antibody in rat experimental autoimmune myocarditis (EAM), using a new animal model of autoimmune myocarditis characterized by the appearance of multinucleated giant cells. EAM was induced by injecting Lewis rats subcutaneously in the footpads with 1.0 mg of human cardiac myosin in an equal volume of Freund's complete adjuvant (FCA) on days 0 and 7. In experiment 1, we evaluated the effect of long-term anti-alpha beta TCR antibody therapy on prevention of progression of EAM. Long-term administration of anti-alpha beta TCR antibody prevented progression of EAM in a dose-dependent manner. Flow cytometry performed at the time of sacrifice showed that the percentage of alpha beta T cells in lymph nodes and spleen was similar in the control group and the group in which almost no histologic evidence of myocarditis was found. In experiment 2, we examined the effects of short-term therapy. Rats were killed at different stages and pathologic specimens were examined. Short-term therapy delayed the onset of myocarditis. Results of flow cytometry suggested that impairment of antigen recognition or T cell function by occupancy of the TCR rather than depletion of TCR was the mechanism responsible for suppression of EAM.

Animals↗
PubMed1994

Conductive property of the zone of slow conduction of reentrant ventricular tachycardia and its relation to pacing induced terminability.

In order to assess the functional characteristics of the zone of slow conduction of reentrant VT, rapid pacing was performed to entrain VT. The orthodromic conduction time was measured as the interval between the stimulus and the orthodromically captured electrogram recorded distal to the zone of slow conduction, but not precisely at the exit point, and its response to rapid pacing was evaluated. In 32 of 33 consecutive patients, rapid pacing was performed to entrain VT. Of these, rapid pacing was repeated in 28 patients at 3-10 cycle lengths in steps of 10 msec before VT was terminated, or rapid pacing produced an acceleration of the rate. A pacing induced prolongation of the orthodromic conduction time (slowed conduction) was observed in 16 (57.1%) patients and in another 12 (42.9%) patients, the conduction time was constant. The pacing induced termination was observed in 93.8% of VT with slowed conduction and in 50% of VT with constant conduction, and the difference was significant (P < 0.05). There was no difference in the cycle length of VT or the shortest paced cycle length between VT with and without slowed conduction. The zone of slow conduction in human VT showed different conductive properties and VT with slowed conduction was associated with an easier and safer terminability with rapid pacing. The fact might be useful in selecting patients for antitachycardia pacing.

Adolescent↗