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Biomedical subjects

M Okabe

Publications and source records attributed to M Okabe.

At least 253 records · Page 14Linked to original sources
PubMed1994

Establishment and characterization of a new Ph1-positive ALL cell line (ALL/MIK) presenting bcr gene rearrangement on bcr-2 and ALL-type bcr/abl transcript: suggestion of in vitro differentiation to monocytoid lineage.

A new Ph1-positive acute lymphoblastic leukemia cell line, designated as ALL/MIK, has been developed from a patient with Ph1-positive acute leukemia. The ALL/MIK cells showed an immunophenotype of common ALL with rearranged JH and Jk genes. The ALL/MIK cells showed no M-bcr rearrangement using Southern blot analysis with either 3' or 5' M-bcr probes, but had the bcr gene rearrangement on bcr-2 within the first intron of the bcr gene. Consistent with this result, the reverse transcriptase-dependent polymerase chain reaction (RT-PCR) assay revealed that the ALL/MIK cells contained the transcript derived fusion of the first exon of bcr gene and the second exon of abl gene. Although the ALL/MIK cells were defined as early pre-B cells by immunophenotypical and genotypical analyses, they were capable of differentiating into monocytoid lineage by when cultured with TPA. Furthermore, another Ph1-positive ALL cell line, (TOM-1), was investigated for its ability to differentiate to monocytoid lineage. TOM-1 was also induced to monocytoid lineage by TPA. Thus, the present study suggested that the leukemic transformation in some Ph1-positive ALL may occur at the level of multipotential hematopoietic cells capable of differentiating towards lymphoid and myelo-monocytoid lineage.

Aged↗
PubMed1994

[Clinical evaluation of patients with right ventricular infarction detected by dual SPECT imaging of thallium-201 and technetium-99m pyrophosphate].

We evaluated clinical significance of dual-nuclide SPECT imaging (D-SPECT) of thallium-201 and technetium-99m pyrophosphate (PYP) in patients of acute inferior left ventricular infarction with PYP uptake in the right ventricle (PYP (+) group) in comparison with those without PYP uptake (PYP (-) group). There was no difference in coronary risk factors, history of angina, blood pressure, heart rate, and hemodynamics on admission between PYP (+) group and PYP (-) group. The duration from onset to admission was longer in PYP (+) group and coronary reperfusion therapies were carried out in few cases. In 7 of 8 PYP-positive patients, the diagnosis of right ventricular infarction was made only by D-SPECT. Four of 8 were complicated with shock within three days, and the duration of hospitalization was longer. Coronary angiography demonstrated many proximal lesions (50%) in PYP (+) group but few ones (18%) in PYP (-) group. D-SPECT was very useful for diagnosing acute right ventricular infarction, and it might contribute to the prevention of shock if performed within a few days.

Aged↗
PubMed1994

[Multiple myeloma with numb chin syndrome as the initial manifestation].

The numb chin syndrome (NCS) is characterized by chin or lower lip numbness restricted to the distribution of the mental nerve (the distal trigeminal nerve). A case of multiple myeloma with polycythemia vera was diagnosed with NCS as the initial manifestation. A 73-year-old Japanese male was admitted to our hospital in April, 1993, because of paresthesia around the chin and lower lip. X-ray film showed multiple osteolytic lesions. According to serum and urine immunoelectrophoresis, lambda type Bence Jones protein was demonstrated. The bone marrow aspiration showed the normocellular marrow with 14.1% myeloma cells. He was diagnosed a suffering from multiple myeloma and was treated with melphalan and prednisolone. He is alive at present with resolution of NCS. We discussed pathogenesis, diagnosis, and treatment of NCS.

Aged↗
PubMed1994

[Preclinical studies for development of anti-cancer drugs: current and historical status and problems].

In this review, we present the current and historical status of preclinical studies for development of new anti-cancer drugs. In our company, especially focusing on the stage of drug screening, pharmacology, toxicology and pharmacokinetic studies. We have discovered numerous new compounds with anti-cancer potential mainly with microbial origins, from which some drugs have been developed to clinical trials. We hope that clinical trials of drugs with a new mode of action will be designed and conducted with a more rational basis, and followed by analysis of the pharmacokinetics and pharmacodynamics so as to predict the toxicity and efficacy of the drugs in humans.

Animals↗
PubMed1993

Identification of Ras farnesyltransferase inhibitors by microbial screening.

A microbial screen using a yeast strain with conditional deficiency in the GPA1 gene was carried out to search for inhibitors of protein farnesyltransferase (PFT). A strain of Streptomyces was found to produce active compounds named UCF1-A, UCF1-B, and UCF1-C. Structural determination of these compounds revealed that UCF1-C is identical to the known antibiotic, manumycin, whereas UCF1-A and UCF1-B are structurally related to manumycin. All three UCF1 compounds suppress the lethality of gpa1 disruption, with UCF1-C exhibiting the strongest activity. UCF1 inhibits yeast as well as rat brain PFT. Fifty percent inhibition of yeast PFT activity is observed with 5 microM UCF1-C. Kinetic analyses of the inhibition suggest that UCF1-C acts as a competitive inhibitor of PFT with respect to farnesyl pyrophosphate, exhibiting a Ki of 1.2 microM, whereas the same compound appears to act as a noncompetitive inhibitor of PFT with respect to the farnesyl acceptor, the Ras protein. UCF1-C shows significant activity to inhibit the growth of Ki-ras-transformed fibrosarcoma, raising the possibility of its use as an antitumor drug.

Alkyl and Aryl Transferases↗
PubMed1993

An enhancer unit of L-type pyruvate kinase gene is responsible for transcriptional stimulation by dietary fructose as well as glucose in transgenic mice.

We produced three lines of transgenic mice containing the 5' flanking region of the L-type pyruvate kinase gene from nucleotides -189 to +37, which includes an enhancer unit and TATA box as functional elements, linked to the chloramphenicol acetyltransferase gene. Since transgene expression was stimulated by both dietary fructose and glucose in a tissue-dependent manner, we suggest that this unit is responsive to both stimuli.

Animals↗
PubMed1993

Membrane cofactor protein (MCP, CD46) in seminal plasma and on spermatozoa in normal and "sterile" subjects.

A sperm protein of molecular mass 43 kDa (the spermatozoa membrane cofactor protein, smMCP) and a seminal plasma protein of 60 kDa (ssMCP) were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting with four monoclonal antibodies (mAb) against membrane cofactor protein (MCP, CD46). These proteins served as factor I cofactors for the cleavage of methylamine-treated C3 (C3ma), the activity of which was blocked by M75, an MCP cofactor-activity-blocking mAb. Thus, these semen proteins are antigenic and functional homologous of MCP. On SDS-PAGE analysis these MCP migrated as single-band proteins which differed from the two-band forms of MCP expressed on other cells. smMCP was N-glycosylated but not O-glycosylated, while ssMCP was O-glycosylated: after deglycosylation of these proteins bands were detected at 38-40 kDa and 43 kDa on SDS-PAGE, respectively. These semen MCP are therefore, structurally different from the conventional MCP. ssMCP in both normal and "sterile" subject groups was determined by sandwich enzyme-linked immunosorbent assay. Seminal plasma in the two groups contained 250-700 ng/ml ssMCP. The difference between the two groups was marginal, although samples from normal subjects tended to show higher concentrations of ssMCP than samples from "sterile" subjects. No molecular difference was observed with ssMCP and smMCP in the two groups by SDS-PAGE/immunoblotting analysis. Immunohistochemical analysis suggested that MCP was positive in glandular epithelial cells and the lumen of the prostate, and in most intra-lumen cells of the testis. Using antibody M177, solubilized prostate and testis were analyzed by immunoblotting and compared with other cell MCP. The major band of MCP in the testis, but not in the prostate, was of 60 kDa, which aligned with ssMCP. No band of testis or prostate MCP, however, aligned with smMCP. ssMCP may be produced in the testis, while the origin of smMCP remains unknown. We hypothesize that ssMCP is important in the survival of spermatozoa, protecting them against local secretion of immunoglobulin and complement in the female genital tract, and that smMCP, which is expressed on acrosome-reacted spermatozoa, plays an essential role in the interaction of spermatozoa with oocytes.

Antigens, CD↗
PubMed1993

Enhancement of antitumor activity of mitomycin C in vitro and in vivo by UCN-01, a selective inhibitor of protein kinase C.

UCN-01 (7-hydroxy-staurosporine) is a potent and selective inhibitor of protein kinase C (PKC), one of several protein kinases examined. UCN-01 itself was shown to exhibit antitumor activity in vitro and in vivo in oncogene-activated human and murine tumor cell lines. Since the mechanism(s) of action of UCN-01 is thought to be different from those of alkylating agents, including mitomycin C (MMC), we tested the combined effect of UCN-01 with MMC on human epidermoid carcinoma A431 cells. UCN-01 potentiated the antiproliferative activity of MMC and yet it did not affect the growth of the cells in vitro. However, other nonselective protein kinase inhibitors, such as staurosporine, K-252a, KT6124 (a derivative of K-252a) and H7, did not enhance the activity of MMC. Isobologram analysis revealed that the interaction of UCN-01 with MMC was synergistic in its antiproliferative activity. A DNA histogram of A431 cells treated with both UCN-01 and MMC showed a block in the cell cycle at the G1/S phase. However, a histogram of cells treated with UCN-01 or MMC alone showed a G1 or a G2M block, respectively. The combined effect of UCN-01 with MMC was further examined in vivo in xenografted A431 cells in nude mice. The combination of both drugs in a single i.v. injection exhibited greater antitumor activity than MMC and UCN-01 alone (P < 0.01). This synergistic antitumor effect was also confirmed in two other solid tumor cell lines, i.e. human xenografted colon carcinoma Co-3 and murine sarcoma 180. The same was observed in the i.v.-inoculated P388 leukemia model, in which we saw an increased lifespan of mice when UCN-01 was combined with MMC. These results suggests the feasibility of using UCN-01 in clinical oncology, especially in combination with alkylating agents such as MMC. In addition, this combination therapy might be a novel chemotherapeutic approach to MMC-insensitive tumors in clinical trials.

Alkaloids↗
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

Central nervous system involvement and generalized muscular atrophy in occipital horn syndrome: Ehlers-Danlos type IX. A first Japanese case.

Occipital horn syndrome (OHS, Ehlers-Danlos syndrome type IX) belongs to the category of the copper metabolism disorders and is at present being investigated biochemically as is Menkes' disease. Unlike Menkes' disease, most patients with OHS have mild submentality. We report a case of OHS with severe central nervous system involvement and muscular atrophy in a 34-year-old male. He had psychomotor retardation and seizures since early childhood and now presented severe mental retardation and generalized muscular atrophy in addition to characteristic facial appearance, hyperelasticity of the skin and joint subluxation. Laboratory investigations revealed a low serum copper and ceruloplasmin level as well as intestinal non-absorption of copper. Radiographic imaging showed occipital exostoses, bladder diverticula, tortuosity of the peripheral vein and osteoporosis of the skeletal bones. The activity of lysyl oxidase, a copper-enzyme involved in cross-link formation in collagen, was found to be decreased in a skin-biopsy specimen. Electron-microscopic investigation of a muscle biopsy showed irregularity of the myofibrillar network and accumulation of concentric laminated bodies in the subsarcolemmal regions.

Adult↗
PubMed1993

Selection of acrosome-reacted human spermatozoa and their fusing ability by micro-injection into the perivitelline space of hamster eggs.

Previously we reported the selective binding of human acrosome-reacted spermatozoa to monoclonal antibody-coated paramagnetic beads. In the present paper, the fusing ability of spermatozoa that bound to the beads was estimated by micro-injecting them into the perivitelline space of hamster oocytes. Acrosome-reacted human spermatozoa were collected by monoclonal antibody-coated paramagnetic beads. Bead-bound spermatozoa were selected under a microscope and micro-injected into the perivitelline space of hamster oocytes. When the injection was begun 5 min after mixing spermatozoa with the beads, 6.6% of the injected spermatozoa fused with an oocyte. However, when the injection was begun 30 min after the mixing, no fusion occurred. Moreover, when spermatozoa were injected with the beads attached to their head, no fusion was observed. The fusing ability of spermatozoa thus prepared was compared with that of randomly chosen and injected spermatozoa. Using spermatozoa from 10 healthy volunteers, 22 independent experiments were performed. The overall fusion rate of injected, randomly selected spermatozoa was 2.8%, whilst that of bead-selected spermatozoa was 7.3%. Selection of spermatozoa by beads appeared to be beneficial to the fusion event.

Acrosome↗
PubMed1993

Reduced bone marrow toxicity of KW-2149, a mitomycin C derivative, in mice.

The bone marrow toxicity of KW-2149, a newly synthesized mitomycin C (MMC) derivative, was compared with MMC in different aged ddY mice. Both MMC and KW-2149 exhibited a similar type of leukopenia in young adult mice. However, in mature adult mice, the recovery from leukopenia was rapid in KW-2149-treated mice, whereas in the MMC-treated mice, it was delayed. The difference between KW-2149 and MMC was more significant in thrombocytopenia in mature mice, and that induced by KW-2149 was mild, whereas that by MMC was severe and delayed. This reduced bone marrow toxicity of KW-2149 in mature mice was confirmed by the assay of colony-forming units in culture, progenitors of granulocytes or macrophages, and megakaryocytic colony-forming units, progenitors of platelets, in the bone marrow cells. The bone marrow toxicity and lethal toxicity of MMC was augmented by weekly intermittent treatment; in contrast, that of KW-2149 was not, suggesting that bone marrow toxicity may have a critical role in the lethal toxicity of MMC. The non-cumulative bone marrow toxicity of KW-2149 enabled the weekly intermittent treatment of human lung adenocarcinoma L-27 inoculated into nude mice. Thus its antitumor activity was greater than with single treatment.

Adenocarcinoma↗
PubMed1993

Combination effect of navelbine (vinorelbine ditartrate) with cisplatin against murine P388 leukemia and human lung carcinoma xenografts in mice.

The in vivo combination effect of navelbine (NVB, KW-2307) plus cisplatin was compared with that of vindesine (VDS) plus cisplatin in terms of antitumor activity and side effects. The antitumor activity of NVB or cisplatin against i.p. inoculated P388 leukemia was augmented by their combination on various schedules when the interval of administrations was within 24 h. Against i.v. inoculated P388 leukemia, the most significant combination effect was observed when cisplatin was administered 4 h after NVB injection (ILS(%) > 451) and three long-term survivors were observed. On this schedule, the combination of LD10 of each drug was achieved, indicating the lack of addition of toxicity. This was further proved by examination of body weight change, white blood cell count and platelet count. Interestingly, significant elevation of blood urea nitrogen concentration by cisplatin was prevented by the combination with NVB. The combination of maximum tolerated dose of NVB and cisplatin was also tolerable in nude mice, and their combination effect was observed against human lung large cell carcinoma Lu-65 and adenocarcinoma PC-12. The number of toxic death mice was more in VDS plus cisplatin-treated groups than in NVB plus cisplatin-treated groups, indicating that the combination chemotherapy of NVB plus cisplatin is a better regimen than that of VDS plus cisplatin in experimental tumor systems.

Animals↗
PubMed1993

Analysis of DNA fragmentation in human uterine cervix carcinoma HeLa S3 cells treated with duocarmycins or other antitumor agents by pulse field gel electrophoresis.

Pulse field gel electrophoresis using a contour-clamped homogeneous electric field was applied for the analysis of DNA-fragmenting activity of antitumor agents towards human uterine cervix carcinoma HeLa S3 cells. Duocarmycins (DUMs), novel antitumor antibiotics with ultrapotent cell growth-inhibitory activities, caused DNA fragmentation at 10 times their IC50 values at 2 h exposure. At 100 times their IC50 values, the size of the smallest fragments was about 245 kilobase pairs (kbp). DUMA, DUMB1 and DUMB2 exhibited similar DNA fragmentation patterns, suggesting similar action mechanisms. DNA fragmentation was also detected in cells treated with radical producers, intercalators and topoisomerase inhibitors. Two bands of about 1800 and 1500 kbp were commonly detected in the cells treated with DUMs and these agents. In addition, fragments of about 900 kbp were detected in the cells treated with a topoisomerase inhibitor, 4'-(9-acridinylamino)methane-sulfon-m-anisidine, and fragments in the broad size range between 700 and 245 kbp in the cells treated with radical producers, bleomycin and neocarzinostatin. DUMs showed a characteristic DNA fragmentation pattern, since both types of fragments induced by the topoisomerase inhibitor and the radical producers were simultaneously detected, suggesting a novel mode of interaction with DNA. DNA-crosslinking agents and mitotic inhibitors did not induce DNA fragmentation under these conditions. The pulse field gel electrophoresis is potentially useful for characterizing DNA-cleaving activity of various antitumor agents at the cellular level.

Antibiotics, Antineoplastic↗
PubMed1993

Sensitivity and specificity of the tilt table test in young patients with unexplained syncope.

UNLABELLED: The usefulness of the head-up tilt testing (HUT) has been previously addressed in diagnosing vasovagal neuroregulatory syncope in the teenage population. However, data concerning sensitivity and specificity is deficient due to the lack of control groups. We compared the response to HUT in young patients referred because of syncope or near syncope (n = 44, mean age 16 +/- 3 years SD) to healthy young volunteers with a normal physical examination and no previous history of syncope (n = 18, mean age 16 +/- 2 years) and to determine the sensitivity and specificity of HUT. The graded tilt protocol was performed at 15 degrees, 30 degrees, and 45 degrees (each for 2 min), and then 60 degrees for 20 minutes. Cuff blood pressure was measured every minute and lead II ECG was continuously monitored. RESULTS: 25 of the 44 patients (57%) developed a vasovagal response or became symptomatic after 13.8 +/- 5.7 minutes of HUT. Three of the 18 volunteers (17%) had a vasovagal response and became symptomatic after 9 +/- 3 minutes of HUT. There was no statistical difference among the four groups (with and without tilt induced vasovagal response) in terms of age and baseline hemodynamic data. The sensitivity of 20 minutes HUT was 57% and its specificity was 83%. The presyncopal hemodynamic response in patients with history of syncope that was characterized by a significant decrease in systolic blood pressure and lack of increase of diastolic blood pressure as compared with baseline and with other groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Orthodromic capture of the atrial electrogram during transient entrainment of atrioventricular nodal reentrant tachycardia.

BACKGROUND: The reentry circuit of atrioventricular nodal reentrant tachycardia (AVNRT) has not been fully demonstrated. We hypothesized that if an upper common pathway was present, the atrial electrogram could not be captured orthodromically during transient entrainment of AVNRT by rapid atrial pacing. Based on this hypothesis, the presence of an upper common pathway was investigated. METHODS AND RESULTS: The atrial electrogram at the recording site of the His bundle potential was identified during induced AVNRT in 9 patients. To entrain AVNRT transiently, rapid pacing from the high right atrium and coronary sinus was applied at a cycle length 10 milliseconds shorter than that of AVNRT and repeated after a decrement of the paced cycle length in steps of 5 milliseconds until AVNRT was interrupted. In 5 of 7 patients, orthodromic capture of the atrial electrogram at the recording site of the His bundle potential was observed during transient entrainment of AVNRT by coronary sinus pacing, ie, the first postpacing interval of the atrial electrogram at the recording site of the His bundle potential was the same as the paced cycle length. In these 5 patients, the mean minimum paced cycle length capable of orthodromic atrial capture was 349 milliseconds, and the mean difference from the cycle length of AVNRT was only 16 milliseconds. During transient entrainment of AVNRT by high right atrial pacing, the atrial electrogram could not be captured orthodromically. CONCLUSIONS: Observation of orthodromic capture of the atrial electrogram at the recording site of the His bundle potential by coronary sinus pacing ruled out the presence of an upper common pathway in AVNRT, and the concept that perinodal atrial tissue is involved in the reentry circuit of AVNRT was supported.

Atrial Function↗
PubMed1993

In situ blotting: a novel method for direct transfer of native proteins from sectioned tissue to blotting membrane: procedure and some applications.

We describe a novel technique for direct transfer of native proteins from unfixed frozen tissues sections to an immobilizing matrix, e.g., nitrocellulose, polyvinyliden difluoride, or positively charged nylon membranes. Proteins are directly blotted onto the membrane, providing optimal accessibility for molecular detection but retaining the anatomic localization at the cellular level. Within 10 min a maximum protein transfer is achieved independent of the protein molecular weight. The total protein bound was 80% of the maximal binding capacity of the blotting membrane and independent of the section thickness. These results indicate that the proteins that bind to the membrane originate from the cut cell monolayer that has direct contact with the blotting membrane. This in situ blotting method provides direct protein mapping from a single cell layer of a tissue section. The procedure includes cryosectioning at 20 microns and collecting sections on a dry blotting membrane at -20 degrees C. For protein transfer the blotted sections are thawed and incubated for 10 min with Tris buffer. After incubation the sections are removed from the membrane by high-pressure spray. The blotted membranes can be subjected to several detection assays. In the present study the presence of several proteins was demonstrated in brain and thymus by immunochemical and enzyme histochemical procedures.

Animals↗