PubMed Health⌕ Search

Biomedical subjects

S Hada

Publications and source records attributed to S Hada.

At least 19 recordsLinked to original sources
PubMed2002

A novel infant acute lymphoblastic leukemia cell line with MLL-AF5q31 fusion transcript.

Infant acute lymphoblastic leukemia (ALL) is characterized by the presence of the proB phenotype (CD10(-)/CD19(+)), poor prognosis and frequent rearrangement of the mixed lineage leukemia (MLL) gene. The most frequent rearrangement is t(4;11)(q21;q23), the role of whose product, the MLL-AF4 fusion transcript, has been extensively studied in leukemogenesis. In a cell line of infant leukemia with MLL rearrangement denoted KP-L-RY, panhandle PCR amplification of cDNA revealed the presence of a fusion transcript, MLL-AF5q31, indicating that AF5q31 is also a partner gene of MLL. In this fusion transcript the MLL exon 6 is fused in frame to the 5' side of the putative transactivation domain of AF5q31. The AF5q31 protein is a member of the AF4/LAF4/FMR2-related family of proteins, which have been suggested to play a role in hematopoietic cell growth and differentiation. The MLL-AF5q31 fusion transcript, although probably rare, appears to be associated with the pathogenesis of infant ALL like MLL-AF4. Co-expression of HoxA9 and Meis1 genes in the KP-L-RY cell line indicated possible functional similarity between MLL-AF4 and MLL-AF5q31. Further understanding of the function of AF5q31 as well as the specific leukemogenic mechanism of MLL-AF5q31 awaits future studies.

Acute Disease↗
PubMed2001

Development of spectral colour banding in cytogenetic analysis.

We developed a novel chromosome banding technique-spectral colour banding (SCAN). With this technique we displayed a multicolour banding pattern that almost entirely correlated with the corresponding G-banding pattern. With SCAN analysis we could identify the chromosome-band origin of double minute chromosomes in gastric cancer. Our preliminary use of this technique suggests that it has significant clinical applications for cytogenetic analysis.

Carcinoma, Signet Ring Cell↗
PubMed1999

Ultraviolet spectroscopic estimation of microenvironments and bitter tastes of oxyphenonium bromide in cyclodextrin solutions.

The UV absorbance and bitter taste of oxyphenonium bromide (OB), an antiacetylcholine drug, in cyclodextrin (CD) solutions are measured, and the local environment of the binding site and the reduction of the bitter taste intensity are quantitatively estimated from the UV data. The UV spectrum of OB is changed with the addition of alpha-, beta-, and gamma-CD, because the phenyl group of OB is included into the CD cavity. The maximum wavelength, lambda(max), senses environmental changes of OB best among several spectral characteristics. From comparison of lambda(max) between a CD solution and the reference ethanol-water and dioxane-water systems, the dielectric constant of the binding site is evaluated. This value leads us to estimate the microenvironment and structure of the binding site. The suppression of the bitter taste of 4 mM OB by CDs is in the increasing order alpha-CD < gamma-CD < beta-CD. The extent of this suppression can be quantitatively predicted from the UV absorbance by assuming that the free OB molecule alone exhibits the bitter taste, regardless of the kind and concentration of CD. Some implications and limitations of the present approach are discussed.

Cyclodextrins↗
PubMed1999

Two separate episodes of hemophagocytic syndrome at a two-year interval in an apparently immunocompetent male.

We describe two separate episodes of hemophagocytic syndrome (HPS) at an interval of two years in a seemingly immunocompetent male. This case suggests the possible existence of an inherent predisposition to HPS, in which otherwise negligible self-limited viral infection may trigger HPS. Laboratory data for a 16-year-old boy admitted with persistent high grade fever and severe thrombocytopenia disclosed coagulation abnormality, liver damage, and hypercytokinemia. A bone marrow aspiration revealed a proliferation of histiocytes with fresh hemophagocytosis. We diagnosed that he was suffering from HPS. Responding to steroid pulse therapy, he recovered completely and was discharged. After two years of healthy life, he became febrile again and was readmitted. The fever was refractory to antibiotics and was associated with a sudden drop in platelet count. Laboratory data and the bone marrow picture were consistent with those of HPS. He was again successfully treated with steroid. After the second episode, he has been healthy for more than two years.

Adolescent↗
PubMed1998

Hemophagocytic syndrome in five patients with Epstein-Barr virus negative B-cell lymphoma.

BACKGROUND: The recent recognition of the association of Epstein-Barr virus (EBV) with T-cell/natural killer cell (T/NK-cell) lymphoma has documented that particular types of EBV-containing T/NK-cell lymphoma are frequently complicated by hemophagocytic syndrome (HPS). This observation suggests that both EBV and proliferating T/NK-lymphoma cells play significant roles in the development of HPS. Cytokines released from neoplastic T cells are presumed to account for the activation of macrophages, which is followed by a complex cascade of cytokine production, resulting in full-blown HPS. Five patients with B-cell lymphoma complicated by HPS were studied for elevated serum cytokines, the association of EBV, and CD25 expression of lymphoma cells; the aim of this study was to verify whether the mechanisms of HPS development hypothesized for T/NK-cell lymphoma also operate in B-cell lymphoma. METHODS: Sera were analyzed for the presence of inflammatory and immunoregulatory cytokines. Flow cytometry, immunohistology (IH), in situ hybridization (ISH), polymerase chain reaction (PCR), and Southern blot analysis were performed using bone marrow aspirates, biopsy specimens, and autopsy specimens. RESULTS: Immunophenotypic and Southern blot studies verified that the lymphoma cells of all five patients were of B-cell lineage. Bone marrow aspirates demonstrated histiocytosis with extensive hemophagocytic activity. Marked elevation of serum cytokines and expression of CD25 were observed in all five patients. However, the results of PCR, ISH using EBER1 probe, and IH for latent membrane protein indicated that these lymphoma cells were free of EBV infection. CONCLUSIONS: In patients with B-cell lymphoma, EBV infection is not necessarily required for the initiation of HPS. In this article, the pathogenesis of HPS assumed to be operative in B-cell lymphoma is discussed with reference to T/NK-cell lymphoma complicated by HPS.

Aged↗
PubMed1998

Chronic myeloid leukemia with minor-bcr breakpoint developed hybrid type of blast crisis.

Although a breakpoint in the minor breakpoint cluster region (m-bcr) of the BCR gene is observed in about two-thirds of patients with Philadelphia chromosome-positive acute lymphoblastic leukemia, this type of genomic rearrangement occurs very rarely in chronic myeloid leukemia (CML). We describe here the eighth case of m-bcr CML, and delineate unique clinical characteristics found in common to the 7 cases reported previously. Monocytosis with a low neutrophil/monocyte ratio resembling chronic myelomonocytic leukemia was the most striking feature of m-bcr CML. Splenomegaly and basophilia were not conspicuous in chronic phase. A high percentage of immature granulocytes and low neutrophil alkaline phosphatase score were the findings in common with classical CML. Lymphoid and myeloid blast changes have been observed at and shortly after presentation so far. We found a hybrid type of blast crisis in the course of m-bcr CML.Thus, m-bcr CML may be a definite subtype of CML, exhibiting distinct clinical characteristics. The presence of fusion product of m-bcr mRNA in an earlier myeloid cell may involve monocytic lineage in addition to myeloproliferative defects.

Blast Crisis↗
PubMed1995

Chemical modification and inactivation of phospholipases A2 by a manoalide analogue.

Chemical modification and inactivation of bovine pancreatic, porcine pancreatic, Naja naja atra and Pseudechis australis phospholipases A2 (PLA2s), belonging to Group I, and of Trimeresurus flavoviridis, Vipera russelli russelli and Agkistrodon halys blomhoffii PLA2s, belonging to Group II, were investigated by the use of a manoalide (MLD)-analogue, 1-(2,5-dihydro-hydroxy-5-oxo-3-furanyl)-8,12-dimethyl-4-formyl-3,7, 11-tridecatrienol. At appropriate time intervals, residual PLA2 activities towards monodispersed, anionic mixed micellar and non-ionic mixed micellar substrates were measured. We tested the protective effect of micellar n-dodecylphosphocholine (n-C12PC) on enzyme inactivation. Inactivation of pancreatic PLA2s (Group I) was only observed towards anionic mixed micellar substrates. This inactivation was completely prevented by the presence of micellar n-C12PC. From a fragmentation study of modified bovine pancreatic PLA2 using lysyl endopeptidase, we speculated that Lys-56 of this enzyme was modified by MLD-analogue and that this modification was responsible for enzyme inactivation. Inactivation of non-pancreatic PLA2s was observed towards all types of substrate, except that no significant inactivation of N. naja atra PLA2 (Group I) towards monodispersed substrate was noted. Micellar n-C12PC protected N. naja atra PLA2 (Group I) completely from inactivation by MLD-analogue, but had lesser protective effects on P. australis PLA2 (Group I), T. flavoviridis and V. russelli russelli PLA2s (Group II). However, no significant protection of A. halys blomhoffii PLA2s (Group II) activity was observed. These results indicate that the inactivation of pancreatic and N. naja atra PLA2s originates from the modification of Lys residues at the interfacial recognition site, and that inactivation of P. australis, T. flavoviridis and V. russelli PLA2s arises from the modification of Lys residues at the catalytic site, interfacial recognition site and regions outside both sites. The inactivation of A. halys blomhoffii PLA2 was assumed to be due to the modification of Lys residues outside the two sites described above.

Amino Acid Sequence↗
PubMed1994

Role of Ca2+ in the binding of phospholipase A2 with a monomeric substrate and with its amide-type analog.

Effects of Ca2+ on the kinetic parameters for the hydrolysis of monodispersed 1,2-dihexanoyl-sn-glycero-3-phosphorylcholine (diC6PC), catalyzed by Group I phospholipases A2 (PLA2s) from Pseudechis australis, Naja naja atra, and bovine pancreas and by Group II enzymes from Vipera russelli russelli, Agkistrodon halys blomhoffii, and Trimeresurus flavoviridis, were studied by the pH-stat assay method at 25 degrees C, pH 7.5-8.2, and an ionic strength of 0.1 or 0.2 in the absence or presence of an amide-type substrate analog, 2-dodecanoyl-amino-1-hexanol-phosphoglycol. The binding of genuine substrate to the Group II enzymes and that of its analog to the Groups I and II enzymes were markedly facilitated by the binding of Ca2+ to the enzymes. On the other hand, the binding of genuine substrate to the Group I enzymes was found to be independent of the Ca2+ binding. The former result suggests that the structures of the Group II enzyme-genuine substrate complexes and both types of enzyme-analog complexes are generally stabilized by the Ca2+ binding, whereas the latter indicates that the structures of the Group I enzyme-genuine substrate complexes are already similar to those of their Ca2+ complexes and that, therefore, these enzyme-substrate interactions are independent of the Ca2+ binding.

Amides↗
PubMed1993

Antithrombotic effect of an anti-glycoprotein IIB/IIIA antibody in primate lethal thrombosis.

We investigated the antithrombotic effect of anti-glycoprotein (GP) IIb/IIIa antibody in a primate model of lethal thrombosis. Eight monkeys were injected intravenously with an anti-CD9 antibody (MALL13). They died within 5 min and displayed severe thrombocytopenia. Histological examination showed multiple platelet thrombi in the pulmonary microvasculature, but no thrombi in the liver, kidneys, or spleen. In contrast, monkeys pretreated with an anti-GPIIb/IIIa antibody (NNKY1-32) at 30 min before MALL13 administration did not die, and the thrombocytopenia in these animals did not develop as rapidly or become as severe. These results suggest that the antiCD9 antibody caused lethal pulmonary thrombosis in vivo, and that pretreatment with the anti-GPIIb/IIIa antibody was able to prevent this thrombosis.

Animals↗
PubMed1993

Hydrolysis of micellar diheptanoylphosphatidylcholine catalyzed by bovine pancreatic phospholipase A2: kinetic characterization of group I and II enzymes.

Initial velocity data for the hydrolysis of micellar 1,2-diheptanoyl-sn-glycero-3-phosphorylcholine (diC7PC) catalyzed by bovine pancreatic PLA2 (Group I) were analyzed using the Michaelis-Menten equation. The Km value for the micellar substrate was found to be independent of Ca2+ concentration, as was the Km value for the monodispersed substrate. The pH dependence curve of Km in the presence of saturating amounts of Ca2+ showed two transitions reflecting large pK shifts of two ionizable groups from 5.0 to 5.45 and from 9.5 to 10.25, whereas the Km value for the monodispersed substrate was independent of pH [Fujii et al. (1991) J. Biochem. 110, 1008-1015]. The pH dependence curve of kcat showed three transitions, indicating the participation of three ionizable groups with pK values of 5.45, 8.4, and 10.25. Deprotonation of the first group and protonation of the third group were found to be essential for catalysis. The respective groups were assigned as the catalytic group His 48, the N-terminal alpha-amino group, and invariant Tyr 52. The present results as well as those for another Group I PLA2 (Naja naja atra) are very different from those for Group II PLA2s (Agkistrodon halys blomhoffii and Trimeresurus flavoviridis), which showed Ca(2+)-dependent substrate binding and no participation of the alpha-amino group in catalysis [Teshima et al. (1989) J. Biochem. 106, 518-527; Nishimura et al. (1992) J. Biochem. 111, 210-218].(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Topical phenytoin in wound healing.

BACKGROUND: Phenytoin, introduced in 1937 as an antiseizure medication, has since been reported to promote wound healing when applied as a topical agent. This study was undertaken to evaluate its effectiveness in chronic skin ulcers. METHODS: Seventy-five inpatients with chronic skin ulcers were included in this controlled trial. Forty patients were treated with topical phenytoin, and 35 patients with conventional saline dressings. Assessment of the wounds included wound area, bacteriologic cultures, and clinical assessment by blind observers at baseline and every 7 days thereafter over the 4-week treatment period. RESULTS: Wound area reduction was greater in the phenytoin group than in controls. Fifty percent of phenytoin-treated wounds had negative cultures by day 7, compared to 17% of controls. Healthy granulation tissue appeared earlier with phenytoin. At the end of the fourth week, 29 of 40 phenytoin-treated ulcers had healed completely versus 10 of 35 controls. CONCLUSIONS: Topical phenytoin appears to be an effective, inexpensive, and widely available therapeutic agent in wound healing. Further clinical use and evaluation is merited.

Administration, Topical↗
PubMed1993

[Measurement of platelet thromboxane A2/prostaglandin H2 receptor in asthmatic patients].

To evaluate the characteristics of platelet TXA2/PGH2 receptors in patients with bronchial asthma, we performed radiobinding assay of gel-filtrated washed platelets obtained from 15 asthmatic patients and 8 normal adults using [3H]-labeled S-145, a TXA2/PGH2 receptor antagonist, as a radiolinged. Data were evaluated by Schatchard's analysis, and the dissociation constant (Kd), an index of the binding characteristic of receptors, and the maximum number of binding sites (Bmax) were calculated. Venous blood was simultaneously collected and was centrifuged, and platelet-rich plasma was prepared. The platelet aggregation rates induced by various concentrations of U-46619, a TXA2 analogue, were measured by Born's method (nephelometry), and the concentration that induced 50% of the maximum platelet aggregation (EC50) was calculated using a concentration-response curve. The Kd value did not differ between the asthmatic patients and normal controls. Some of the asthmatic patients showed a low EC50 and a high Bmax. EC50 was inversely correlated with Bmax. The number of platelet TXA2/PGH2 receptors was shown to be increased in some asthmatic patients.

Adult↗
PubMed1993

[Study on the inhibitory effect of AA-2414 on platelet aggregation and its clinical effect in asthmatic patients].

We previously reported that AA-2414, an eicosanoid receptor antagonist, inhibits platelet aggregation mediated by TXA2/PGH2 receptors in patients with bronchial asthma, but that the inhibitory effects differ among individuals. In this study, we measured the in vitro inhibition rate of platelet aggregation by AA-2414 using U-46619 as an aggregating agent in 22 asthmatic patients and classified them into Group A (showing an inhibition rate of 60% or more) and Group B (showing a rate of less than 60%). Subsequently, AA-2414 tablets (40 mg/day) were orally administered to both groups for 6 weeks, and the clinical effects were compared. A positive correlation was observed between the in vitro U-46619-induced platelet aggregation rate and the inhibition rate of aggregation by AA-2414. At the end of administration, marked inhibition of U-46619-induced platelet aggregation was observed in all patients. However, Group A showed a higher improvement rate of symptoms than Group B. Asthmatic patients can be classified into the groups showing good or poor platelet responses. The response may reflect reactivity to TXA2 in the local airway.

Adult↗
PubMed1990

[Clinical study on the inhibitory effect of AA-2414 on platelet function in asthmatic patients].

We studied the effect of AA-2414, a TXA2 receptor antagonist, on platelet function in 12 asthmatic patients, 6 males and 6 females, whose mean age was 43.6 years. AA-2414 was orally administered to each patient at 20 mg/day for two weeks and then at 40 mg/day for the following two weeks. Platelet aggregation, plasma concentration of TXB2, and serum concentrations of AA-2414 and its metabolites were measured before and after the administration of each dose. Platelet aggregation induced by U-46619 (an analogue of PGH2), STA2 (a stable analogue of TXA2) and arachidonic acid with the administration of AA-2414 was significantly inhibited. The degree of this inhibition was proportional to the serum level of the drug. Plasma concentration of TXA2 tended to be lowered by administration of AA-2414, but it was not statistically significant. Eight (75.0%) of the 12 patients showed clinical improvement. In the cases where the drug was ineffective, the inhibition of platelet aggregation after administration of AA-2414 was less than in those cases where it was effective. We conclude that AA-2414 might exert its antiplatelet and antiasthmatic effects through antagonism of the TXA2 receptor. Investigation of the response to AA-2414 may be useful in assessing the clinical effect of this compound.

Administration, Oral↗