Biomedical subjects

M Kasai

Publications and source records attributed to M Kasai.

At least 271 records · Page 15Linked to original sources

PubMed1993

Characterization of a Cl(-)-channel from rabbit transverse tubules in the planar lipid bilayer system.

A Cl(-)-channel of the transverse tubule(TT) was incorporated into artificial planar lipid bilayers and its properties were investigated. The channel was found to have the following properties. (1) The single-channel conductance is 40 pS in choline-Cl solution. (2) The rate of gating of the channel does not depend on the membrane voltage. (3) The channel is blocked by stilbene derivatives (DIDS and SITS), which are known as inhibitors of voltage-dependent Cl(-)-channels of the Torpedo electric organ, from both sides of the membrane. (4) An inhibitor of voltage-dependent Cl(-)-channels of skeletal muscle, 9-anthracene carboxylic acid(9-AC), inhibits Cl(-)-current from the cis-side to which the TT vesicles were added.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed1993

Tolerance induction by clonal deletion of CD4+8+ thymocytes in vitro does not require dedicated antigen-presenting cells.

The cellular requirements of T cell tolerance induction in the thymus by clonal deletion was investigated by using an in vitro assay: thymocytes from mice expressing a transgenic TcR specific for lymphocytic choriomeningitis virus (LCMV) and H-2Db were co-cultured with various H-2b cell types as antigen-presenting cells in the presence of the antigenic LCMV peptide. The results revealed that all cell lines examined including embryonic and transformed fibroblasts, melanoma cells, cortical thymic epithelial cells, lymphomas and neuronal cells induced an antigen dose-dependent deletion of CD4+8+ thymocytes. Similarly, highly enriched accessory cell populations from thymus and spleen (macrophages, dendritic and cortical epithelial cells, i.e. thymic nurse cells) could induce antigen-specific depletion of immature CD4+8+ thymocytes. Depending on the cell type examined micromolar to picomolar concentration of LCMV peptide were required to induce deletion. The effectiveness of deletion by the different cell types did not correlate with their major histocompatibility class I expression level; it was, however, influenced by the presence of ICAM-1 adhesion molecules.

Animals↗

PubMed1993

Successful vitrification of bovine blastocysts, derived by in vitro maturation and fertilization.

Bovine blastocysts were produced through maturation, fertilization, and development in vitro. For vitrification, solutions designated EFS, GFS, and PFS were prepared; these were 40% ethylene glycol, 40% glycerol, and 40% propylene glycol, respectively, diluted in modified phosphate-buffered saline (PBS) containing 30% Ficoll + 0.5 M sucrose. The embryos were exposed to the solutions in one step at room temperature, kept in the solutions for various times, vitrified in liquid nitrogen, and warmed rapidly. When the embryos were vitrified in EFS solution after 1 or 2 min exposure, the postwarming survival rate, assessed by the reexpansion of the blastocoel, was 74-77%. However, when the exposure time was extended to 3 min or longer, this rate dropped to 7-0%. This reduction was attributed to the toxicity of ethylene glycol. Of the embryos vitrified in GFS solution, 53% survived when they were cooled after 1 min exposure; as the duration of the exposure increased, the survival rate increased, reaching a peak (72%) at 4 min. The rate then decreased gradually with exposure time. In PFS solution, embryos surviving after vitrification were recovered only with 1 min exposure (33%), reflecting the high toxicity of propylene glycol. After vitrification in EFS or GFS solution, two embryos were nonsurgically transferred into each of 14 recipient animals. Of the 14 recipients, ten (71%) became pregnant; two resulted in early stillbirths, four recipients delivered twins (four alive and four stillborn), and two delivered single live calves, demonstrating the effectiveness of this simple vitrification method for the cryopreservation of in-vitro-produced bovine blastocysts.

Animals↗

PubMed1993

Proenzyme from of cathepsin L produced by thymic epithelial cells promotes proliferation of immature thymocytes in the presence of IL-1, IL-7, and anti-CD3 antibody.

A thymic epithelial cell line (TEC1-4) established from newborn mouse thymus produced a cofactor to promote proliferation of double-negative (CD4-8-) thymocytes in the presence of IL-1, IL-7, and anti-CD3 antibody. Based upon the sequence of 8 amino acid residues near the N terminal portion, the factor was identified as the mouse proenzyme form of cathepsin L which is almost identical to the rat proenzyme form of cathepsin L (95% in homology). Production of the proenzyme form of cathepsin L was confirmed in the TEC1-4 and mouse embryonic thymus by Western blotting analysis and Northern blotting analysis. Furthermore, immunohistologically, the presence of cathepsin L was observed in the epithelial cells of the subcapsular layer and around the small vessels in the thymic cortex. It has been concluded that a subpopulation of thymic cortical epithelial cells produces the proenzyme form of cathepsin L which can act as a cofactor to promote proliferation of DN immature thymocytes.

Amino Acid Sequence↗

PubMed1993

Disposition and metabolism of KW-2149, a novel anticancer agent.

KW-2149 is a new derivative of mitomycin C (MMC). The plasma concentrations, distribution, metabolism, and excretion of [3H]-KW-2149 in normal and tumor-bearing mice after i.v. administration of 16.6 mg/kg were investigated. The plasma radioactivity decreased biexponentially after i.v. administration in normal mice. However, the unchanged drug disappeared rapidly, showing a half-life (t1/2) of 9.7 min, which was shorter than MMC's (18 min). The radioactivity was excreted in mouse urine (33%) and feces (58%) within 144 h. High radioactivity was distributed in the gallbladder, liver, kidney, pancreas, and lung at 1 h after i.v. administration to normal mice. The tumor concentration was lower than the plasma or blood concentration. The lowest radioactivity was observed in the brain. The metabolic rate of KW-2149 was very rapid. The methyl sulfide form (M-16), the symmetrical disulfide dimer (M-18), and the albumin conjugate were detected in plasma, which possessed anticellular activity. The specific anticellular activity of these compounds against uterine carcinoma (HeLa S3) was 1/100, 1, and 1/20 respectively, as compared with that of KW-2149.

Animals↗

PubMed1993

Comparison of uptake of mitomycin C and KW-2149 by murine P388 leukemia cells sensitive or resistant to mitomycin C.

KW-2149, a new mitomycin C (MMC) derivative, inhibited the growth of murine P388 leukemia in vitro at 20-fold lower concentrations than those of MMC. KW-2149 was also effective in inhibiting the growth of MMC-resistant P388 (P388/MMC) cells. To elucidate these characteristics of KW-2149, its uptake and efflux were compared with those of MMC in MMC-sensitive and -resistant P388 cells. Both MMC and KW-2149 accumulated rapidly in P388 cells after incubation at the concentration of 0.47 and 0.024 microM, respectively, which were the IC50 values at 1-h exposure. Although this concentration of KW-2149 was 20 times lower than that of MMC, its intracellular concentration was little more than that of MMC, suggesting that KW-2149 accumulated in the cells quite efficiently. The accumulated KW-2149 in the cells after 1-h treatment remained for as long as 24 h after the incubation of the cells in drug-free medium, suggesting that most of the intracellular KW-2149 or MMC was bound to cellular components. The ratios of resistance of P388/MMC cells to MMC and KW-2149 were 34 and 8.8, respectively, at 1-h exposure, suggesting that P388/MMC cells were partially resistant to KW-2149 in vitro. P388/MMC cells also showed partial resistance to cisplatin, Adriamycin, m-AMSA, and etoposide. The accumulation of MMC in P388/MMC cells was lower than that in P388 cells, although the size of the former cells was almost equal to that of the latter. As a result, the amount of DNA-bound MMC was lower in P388/MMC cells than in P388 cells, suggesting its involvement in the mechanisms of MMC resistance in P388/MMC cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1993

Monoclonal gammopathy (IgA: lambda) after autologous T-cell-depleted bone marrow transplantation in a patient with non-Hodgkin's lymphoma.

We report a case study of a patient suffering from T-lymphoblastic lymphoma, for whom autologous T-cell-depleted bone marrow transplantation was carried out. Low-dose cyclosporin A (CsA) was administered just after autologous bone marrow transplantation (ABMT) for induction of autologous graft-versus-host disease. Three months later, the lymphoma relapsed with marked monoclonal gammopathy of the immunoglobulin A type, which had not been seen before ABMT. It is suggested that the regrowth of the lymphoma cells was related to the maturation of B cells or the secretion of immunoglobulins from plasma cells, associated with some cytokines produced under the condition of an abnormal immunological circumstance after ABMT plus CsA.

Adult↗

PubMed1993

Vitrification of mouse oocytes and embryos at various stages of development in an ethylene glycol-based solution by a simple method.

Mouse oocytes and embryos at various developmental stages were exposed directly to an ethylene glycol-based vitrification solution (EFS) for 2 or 5 minutes at 20 degrees C. They were then vitrified at -196 degrees C and were warmed rapidly. At the germinal vesicle stage, the proportion of morphologically normal oocytes was 36 to 39% if they had cumulus cells, whereas in cumulus-removed immature oocytes and in ovulated oocytes it was only 2 to 4%. This low survival was attributed to the harmful action of ethylene glycol. After fertilization, on the other hand, the post-warming survival rate of 1-cell zygotes, as assessed by cleavage to the 2-cell stage, increased markedly (62%). As the developmental stage proceeded, higher proportions of vitrified embryos developed to expanded blastocysts; the rates increased up to 77 and 80% in 2-cell and 4-cell embryos, respectively. For embryos at the 8-cell, morula and early blastocyst stages, the proportion of embryos developed after vitrification (90 to 95%) was not significantly different from that of the untreated embryos (95 to 100%) when the period of exposure to EFS solution was 2 minutes. As the blastocoel began to enlarge, however, survival began to decrease again, with rates of 79 and 57% in blastocysts and expanded blastocysts, respectively. After the cryopreserved 2-cell, 4-cell and 8-cell embryos as well as morulae and blastocysts were transferred to recipients, 43 to 57% of the recipients became pregnant, and 48 to 60% of these various stage embryos developed into live young.

Journal Article↗

PubMed1993

Iron responsive element-binding protein (IRE-BP) in leukemic cells: analysis using enzyme-linked immunosorbent assay and semiquantitative polymerase chain reaction.

The level of iron responsive element-binding protein (IRE-BP) in leukemic cells, which is essential for iron homeostasis and plays an important role in cell metabolism and cell growth, was measured using an enzyme-linked immunosorbent assay (ELISA). Comparing the levels in different clinical stages, the levels in CML cells in the chronic phase (mean +/- S.E., 0.270 +/- 0.110 U/mg protein, n = 9) and those in AML cells (0.150 +/- 0.104 U/mg) protein, n = 21) were significantly lower than that in normal granulocytes (0.628 +/- 0.216 U/mg protein, n = 9, p < 0.001 vs CML and AML). Analysis of IRE-BP mRNA expression in leukemic cells using semiquantitative polymerase chain reaction showed suppressed expression of mRNA as compared to normal bone marrow cells. These observations suggest that there may be dysregulation of IRE-BP expression and production in leukemic cells.

Adult↗

PubMed1993

Effects of ryanodine on permeability of choline and glucose through calcium channels in sarcoplasmic reticulum vesicles.

The effect of ryanodine on the permeation of glucose, choline, and Ca2+ through the Ca2+ channel in sarcoplasmic reticulum vesicles was studied by means of the light scattering and/or the tracer method. Ryanodine had the same effect on the permeabilities of choline and Ca2+; low concentrations of ryanodine (10 microM) locked the channel in the open state, and high concentrations (100 microM) opened the channel transiently, which closed finally. Glucose became permeable on the ryanodine treatment even in the absence of KCl, although it was not permeable before the treatment when the channel was open. Submolar concentrations of KCl enhanced the glucose and choline permeability of the ryanodine-treated channel as well as the untreated one. Activators such as ATP and caffeine did not enhance the permeability of the treated channel in the open locked state, but inhibitors such as Mg2+ and ruthenium red closed the channel, although much higher concentrations were required than for the untreated channel. The maximal rates of choline and glucose permeation of the ryanodine-treated channel were lower than those of the untreated one attained in the presence of ATP and/or caffeine. This result is consistent with the fact that the single channel conductance after the ryanodine treatment decreased to 40-50% of the maximal conductance of the untreated one. This result suggests that the conformation of the channel opened by ryanodine was different from that with ATP or caffeine.

Adenosine Triphosphate↗

PubMed1993

Cytokine gene expression in peripheral blood mononuclear cells during graft-versus-host disease after allogeneic bone marrow transplantation.

Cytokine gene expression in peripheral blood mononuclear cells during the development of graft-versus-host disease (GVHD) in patients who underwent allogeneic bone marrow transplantation (allo BMT) was analysed using a semiquantitative reverse-transcriptase polymerase chain reaction (RT-PCR). The expression of interleukin (IL)-1 beta, IL-6, and tumour necrosis factor (TNF)-alpha mRNA was increased during the development of GVHD and the degree of this increment depended on the severity of the disease. IL-2 expression was not detected at all and interferon-gamma expression was not much changed during GVHD. In patients with hepatic veno-occlusive disease (VOD), another transplantation-related complication, the expression of IL-1 beta and TNF-alpha mRNA was increased but IL-6 mRNA expression showed little increase. These findings suggest that IL-1 beta, IL-6 and TNF-alpha produced by peripheral blood mononuclear cells play an important role in the development of GVHD. Furthermore, liver dysfunction due to GVHD or VOD may be distinguishable by this type of cytokine analysis. Analysis of cytokine mRNA expression in peripheral blood mononuclear cells after allogeneic bone marrow transplantation may provide important information concerning the immune response and the cytokine network system in marrow transplant patients.

Adolescent↗

PubMed1993

Membrane properties of identified guinea-pig paraventricular neurons and their response to an opioid mu-receptor agonist: evidence for an increase in K+ conductance.

Intracellular recordings were obtained from neurons in the paraventricular nucleus (PVN) of guinea-pig hypothalamic slices. Passive and active properties of the neurons were determined, and when possible, recorded neurons were injected with biocytin. The effects of a mu-receptor opioid agonist [D-Ala2, Nme-Phe4, Gly5-ol]enkephalin (DAGO) were studied in order to determine which types of cells have mu receptors and to test the hypothesis that an increase in K+ conductance causes mu-receptor-mediated inhibition in the PVN. The recorded cells inside the PVN were divided into two groups, primarily on the basis of the presence or absence of a low threshold Ca2+ spike (LTS). In one group of neurons, LTS potentials could not be evoked (non-LTS cells, n = 42). In another group of neurons (n = 35), LTS potentials with one or two Na+ spikes could be initiated with depolarizing pulses superimposed on steady hyperpolarizing currents; however, these neurons did not fire robust bursts (i.e. non-bursting LTS cells). The mean time constant of non-LTS cells (19.9 +/- 1.6 ms; mean +/- SEM) was significantly shorter than that of non-bursting LTS cells (26.7 +/- 2.1 ms). There were no differences in the mean resting membrane potential, spike amplitude, spike duration, input resistance, spike threshold and pattern of synaptic inputs between the two groups. Intracellular labeling with biocytin combined with cresyl violet counter-staining demonstrated that the two types of cells were located in the PVN.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

[Large scale outbreak of Yersinia pseudotuberculosis serotype 5a infection at Noheji-machi in Aomori Prefecture].

In June 1991, there were large scale outbreaks of Yersinia pseudotuberculosis at 4 primary schools and 1 junior high-school in Noheji-machi in Aomori Prefecture. A total of 732 patients (725 pupils and school children, 7 teachers and personnel) were affected and 134 were hospitalized. Sex ratio of incidence was 1.1:1.0 without appreciable difference. Clinical symptoms (478 patients) were represented frequently by pyrexia (86.4%), eruption (73.8%), abdominal pain (66.7%), vomiting nausea (63.4%), etc., and were characterized by a strawberry tongue, pharyngeal redness, membranous desquamation of the fingers and arthralgia during convalescence. Yersinia pseudotuberculosis was isolated from 27 (81.8%) of 33 patients stool specimens, 1 waste water specimen and 2 (11.7%) of cooking employees' stool specimens. The isolates were confirmed serotype 5a, and positive for calcium-dependency and autoagglutination, and harboring 40-50 megadalton virulent plasmid. Restrictive endonuclease digestive pattern of plasmid proved to be identical. In many cases, patients' serum antibody titer showed a significant increase ratio to the isolated strain. In term of drug susceptibility, all the strains were sensitive to cefem, penicillin and amino-glycoside series and resistant to macrolide and sulfa series. The infectious source was limited to the school feeding, but the responsible food remained unknown. Mean latency and exposure day were presumed to be 6.5 days and May 30, respectively.

Adolescent↗

PubMed1993

Cryopreservation of expanded mouse blastocysts by vitrification in ethylene glycol-based solutions.

Experiments were conducted to find optimal conditions for obtaining high survival of expanded mouse blastocysts after vitrification. The vitrification solutions used were designated EFS20, EFS30 and EFS40, and contained 20%, 30% and 40% ethylene glycol, respectively, diluted in PB1 medium containing 30% Ficoll plus 0.5 mol sucrose l-1. In the toxicity test of the solutions and each cryoprotectant, ethylene glycol was found to be toxic to embryos. For vitrification, expanded blastocysts were exposed to the vitrification solutions at 10, 20 or 25 degrees C for various periods; they were then cooled rapidly in liquid nitrogen, after which they were warmed rapidly. When the embryos were directly exposed to EFS40 at 20 degrees C for 2 min before vitrification, 66% of them re-expanded during 48 h of post-warming culture. The re-expansion rates decreased when exposure time was shortened (0.5 min), when exposure temperature was lowered (10 degrees C), or when embryos were vitrified in EFS20 and EFS30, although these conditions should be less toxic. When embryos had been pretreated in a dilute (10-20%) ethylene glycol solution for 5 min, followed by short exposure (0.5 min) to EFS40 at 20 degrees C, post-vitrification survival rate increased to 83-84%; furthermore, the rate reached 94% when the temperature was increased to 25 degrees C. Expanded blastocysts cryopreserved by this two-step method developed into live young as well as control embryos after transfer.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

[Immunological study on Alzheimer's disease using anti-beta-protein monoclonal antibodies].

Monoclonal antibodies (TB1 & TB2), which were obtained by immunization of 24 amino acids in BALB/c mice, bound specifically to the amyloid senile plaque and amyloid-angiopathic lesions of brain tissues of patients with Alzheimer's disease (AD) or with senile dementia of Alzheimer type (SDAT), and strongly reacted with the 1st part (Asp-Ala-Glu-Phe-Arg-His-Asp) of beta-protein. Western blotting and two-dimensional immunoelectrophoresis of cerebrospinal fluid (CSF) and serum revealed bands of 125 and 20 kilodaltons. The positive frequency of 125 and 20 KD bands detected by two-dimensional immunoelectrophoresis was higher in the serum of AD and SDAT patients (12 cases) than in that of normal control patients. ELISA employing various anti-amyloid precursor protein (APP) antibodies was performed using the extract of the human neuroblastoma cell line (NB39) which produces APP. In the near future, we hope to measure APP in CSF and sera from patients with Alzheimer's disease.

Aged↗

PubMed1993

Synthesis and structure-activity relationships of new dimeric mitomycin derivatives; 7-N,7'-N'-bis(omega-thioalkyl)dimitomycins.

The reaction between mitomycin A (1) and cysteamine afforded 7-N,7'-N'-bis(2-thioethyl)dimitomycin C (7), 7-N-[2-[(2-aminoethyl)dithio]ethyl]mitomycin C (8), and 7-methoxy mitosenes (10, 11). The structures of 7 and 8 were elucidated on the basis of spectroscopy and reactions between 1 and 8, and 1 and cystamine. The observation of the time course for the reaction revealed the mechanism of the formation of 7 and 8. The rapid oxidation of cysteamine by the quinone of 1 gave cystamine, which was trapped by 1 to give 8, and 8 was additionally reacted with 1 to give 7. Since 7 showed significant antitumor activities, related 7-N,7'-N'-bis(omega-thioalkyl)dimitomycins were synthesized. They also showed remarkable antitumor activities against HeLa-S3 in vitro, sarcoma 180 (sc-ip), leukemia P388 (ip-ip) in vivo. In these evaluations, compound 7 demonstrated unique potency.

Animals↗

PubMed1993

pH-dependent inactivation of DT-diaphorase by mitomycin C and porfiromycin.

Mitomycin C and porfiromycin were found to inactivate rat hepatic DT-diaphorase. Inactivation was pH dependent; little inactivation was detected at pH 5.8, but inactivation increased as the pH was raised to 7.8. Inactivation was concentration and time dependent and displayed pseudo-first-order kinetics. Inactivation was NADH dependent, indicating that reductive metabolism was necessary for inhibition. [3H]Mitomycin C was covalently bound to DT-diaphorase during inhibition, and the stoichiometry for inactivation of DT-diaphorase by mitomycin C was approximately 0.8 nmol of mitomycin C bound/nmol of enzyme. A higher molecular mass product (60 kDa) was detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis of DT-diaphorase preincubated with NADH and mitomycin C at pH 7.8, suggesting that mitomycin C is capable of cross-linking DT-diaphorase. The kinetics of inhibition, requirement for NADH for inhibition, covalent binding of [3H] mitomycin C to DT-diaphorase, and approximate 1:1 stoichiometry suggest that this inactivation process may be mechanism based. Inhibition of DT-diaphorase by mitomycin C and porfiromycin is not limited to a cell-free system and could also be observed in HT-29 cells in culture at pH 7.2. Bioactivation of mitomycin C or porfiromycin by DT-diaphorase is favored at lower pH, whereas at higher pH values enzyme alkylation and inactivation of DT-diaphorase occur. These data suggest that the success of attempts to exploit the elevated DT-diaphorase content of certain human tumors for improved chemotherapeutic response using mitomycin C or porfiromycin will depend on intracellular pH.

Animals↗

PubMed1993

Bone marrow transplantation for hematological diseases in Hokkaido--June 1985 to December 1991.

Bone marrow transplantation (BMT) was started in Hokkaido in 1985. In the present report we have reviewed the clinical outcome of patients treated with BMT for hematological diseases in Hokkaido. Fifty-eight allogeneic and 19 autologous transplants were registered by December 1991. The underlying diseases consisted of 47 leukemias, 14 lymphomas, 10 aplastic anemias and six myelodysplastic syndromes. Among the allogeneic BMT cases, 55 were human leucocyte antigen (HLA) identical and three were mismatched. Among the autologous BMT patients, two received their marrow purged with 4-hydroperoxycyclophosphamide and five, with monoclonal antibodies and complements. The conditioning regimens used for malignancies were chiefly cyclophosphamide (CY) plus total body irradiation, or busulfan plus CY. In many cases, cytokines were used for rapid recovery of decreased leukocytes. Engraftment was observed in 50 out of 52 evaluated allogeneic and 18 out of 19 autologous transplants. Ten allogeneic patients suffered from severe acute graft-versus-host diseases (GVHD), and extensive chronic GVHD appeared in 16 patients. Relapses were observed in four cases of allogeneic BMT and six of autologous BMT. The major complications were interstitial pneumonitis (IP) and severe infections. Long-term survival rates were almost 60% in both allogeneic and autologous transplants. Mild acute GVHD and limited chronic GVHD increased the survival rates. The results indicated that substantial problems such as GVHD, IP and relapses must be controlled in the near future for an improved outcome to be made possible.

Adolescent↗