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Biomedical subjects

H Kawabata

Publications and source records attributed to H Kawabata.

At least 109 records · Page 6Linked to original sources
PubMed1996

High levels of Ca(2+)-independent endonuclease activity capable of producing nucleosomal-size DNA fragmentation in non-adherent marrow mononuclear cells from patients with myelodysplastic syndromes and acute myelogenous leukemia.

The endogenous endonucleases capable of producing nucleosomal-size DNA fragmentation are considered candidates of the key enzyme of apoptosis. We examined these activities in the nuclear fraction of non-adherent marrow mononuclear cells (NonAd-MNCs) from patients with myelodysplastic syndromes (MDS) and acute myelogenous leukemia (AML) using a nuclear autodigestion method. We detected Ca2+/Mg(2+)-dependent endonuclease activity in all samples examined. In contrast, Ca(2+)-independent activity with the ability to produce nucleosomal-size DNA fragmentation was found only in samples from a proportion of patients with MDS (12 of 26 consecutive cases) and all the patients with AML (n = 6), but not in the samples from control group patients (n = 10). This activity was correlated with the percentage of bone marrow (BM) blast cells to some extent. Although the levels of these endogenous endonuclease activities seem not to be correlated directly with the susceptibility of the cells to apoptosis, we postulate that the Ca(2+)-independent endonuclease activity may be associated with apoptosis and/or cell proliferation. Further follow-up study of these patients may be meaningful to clarify the prognostic significance of the Ca(2+)-independent endonuclease activity in patients with MDS.

Adult↗
PubMed1996

[Apoptosis in MDS].

We examined the endonuclease activity capable of inducing internucleosomal DNA fragmentation in hematopoietic cells. Mg(2+)-dependent nuclease activity was high in hematopoietic progenitor cells and the activity decreased with myeloid or erythroid differentiation. This was the case in MDS as well as in normal hematopoiesis. In contrast, Ca2+/Mg(2+)-dependent nuclease activity varied widely in the samples from MDS and the possibility was indicated that the activity of Glycophorin A+ cells was related to the degree of anemia. We also investigated DNA strand breaks in bone marrow samples from 16 patients with MDS and 10 with other diseases by an in situ end labeling (ISEL) technique. The reactivity in ISEL tended to increase parallel to disease progression of MDS. The high ISEL-positivity was also observed in some samples from patients with MPD and other diseases. Though ISEL is a useful technique for quantification of apoptosis, our results suggested that MDS cells with ISEL positive staining are not necessarily in the process of apoptosis.

Apoptosis↗
PubMed1996

[Sensitivity loss in short wavelength sensitive cones in myopic eyes].

To investigate early changes of visual function in high myopic eyes, the relative sensitivity of the short-wavelength sensitive cones (s-cones) was measured by flash-evoked cortical potentials and electroretinograms and their relation with refractive error and axial length of the eyes was studied. A Ganzfeld stimulus was employed. The subjects were all under 37 years of age and were divided into 3 groups according to the magnitude of the refractive error as follows; 1) emmetropia/low myopia group (10 eyes), between +0.50 D and -3.00 D; 2) medium myopia group (8 eyes), between -3.25 D and -6.00 D; and 3) high myopia group (10 eyes), over -6.25 D. Their corrected visual acuities were better than 1.0 and their color vision was normal according to Panel D-15 and SPPII. They had no other ophthalmological abnormalities except tigroid fundus. The s-cone sensitivity was significantly correlated with the refractive error and axial length (p < 0.001) and was reduced prior to ophthalmoscopic retinal changes in the medium and high myopia groups. This indicates that the site of s-cone sensitivity loss in myopia is in the retinal.

Adolescent↗
PubMed1995

Types of nuclear endonuclease activity capable of inducing internucleosomal DNA fragmentation are completely different between human CD34+ cells and their granulocytic descendants.

A hallmark of apoptosis is internucleosomal DNA fragmentation resulting from the activation of endonucleases. We characterized the endonuclease activity of human myeloid cell nuclei that cleaved their own nuclear chromatin to oligonucleosomal length fragments. Polymorphonuclear leukocytes (PMNs) of normal peripheral blood contained both Ca2+/Mg(2+)-dependent and DNase II-like acidic endonuclease activities in their nuclei. Immature myeloid cells of normal bone marrow at various stages of granulocytic maturation had similar nuclease activities. In contrast, a clear difference was shown in the circulating CD34+ cells, in that only Mg(2+)-dependent, Ca(2+)-independent endonuclease activity was detected. Consistent with these findings is the emergence of the Ca2+/Mg(2+)-dependent and acidic endonuclease concomitantly with the disappearance of the Mg(2+)-dependent endonuclease when CD34+ cells were induced to differentiate in vitro toward granulocytes. Leukemic cell lines of all lineages also had Mg(2+)-dependent nuclease activity. Our results suggest an association of the Mg(2+)-dependent endonuclease with hematopoietic progenitor cells and that the relative activities of the nuclear nuclease in human myeloid cells change substantially during granulocytic differentiation.

Antigens, CD↗
PubMed1995

Immunohistochemistry of gap junctions in normal and diseased gastric mucosa of humans.

BACKGROUND & AIMS: Intercellular communication through gap junctions has been proposed to be an important mechanism for the maintenance of tissue homeostasis. However, few studies have considered the role of gap junctions in gastric mucosa. The purpose of this study was to evaluate the distribution of gap junction-specific proteins in normal and diseased gastric mucosa of humans. METHODS: Biopsy specimens were obtained endoscopically. Immunohistochemical staining was performed by standard immunoperoxidase techniques using an anti-connexin 32 monoclonal antibody. RESULTS: In normal gastric mucosa, connexin 32 was present chiefly in the foveolar cells and in a decreasing staining gradient extending down to the necks of the glands. Connexin 32 also was observed in the epithelial cells of atrophic mucosa in a pattern similar to that observed in normal controls. Conversely, the majority of the foveolar cells adjacent to erosions had reduced or absent staining. Connexin 32 also was reduced significantly or absent from metaplastic epithelial cells. No malignant cells from patients with carcinoma contained detectable connexin 32. CONCLUSIONS: Intercellular communication likely is impaired in precancerous or paracancerous lesions of the stomach. Abnormal intercellular communication thus may play an important role in the progression from mucosal injury to intestinal metaplasia and/or gastric carcinoma.

Adult↗
PubMed1995

Apoptosis in myelodysplasia: a paradox or paradigm.

A growing body of evidence indicates that certain diseases are associated with increased apoptosis or inhibition of apoptosis. Among them, the myelodysplastic syndromes (MDS) are unique in that apoptosis is related, in apparently opposite directions, to the various facets of MDS. Ineffective hematopoiesis may be related to excessive intramedullary cell death via apoptosis and leukemic transformation conceivably results from escape from the apoptotic control. Future studies should be directed to define cellular susceptibility to and circumvention from apoptotic control mechanism(s).

Apoptosis↗
PubMed1995

Identification of spirochetes isolated from wild rodents in Japan as Borrelia japonica.

Spirochetes isolated from three species of wild mice, Apodemus speciosus, Apodemus argenteus, and Eothenomys smithi, which were caught on Honshu, Japan, were characterized on the bases of protein profiles, reactivities with monoclonal antibodies (MAbs), and DNA homology values. All the isolates reacted with MAb O1441b, which is specific for Borrelia japonica, but not with MAb P62, which is specific for Borrelia burgdorferi sensu stricto, Borrelia garinii, and Borrelia afzelii. The DNA relatedness of four representatives isolates to strain HO14, a type strain of B. japonica, was 83 to 88%. From these findings, the spirochetes were identified as B. japonica.

Animals↗
PubMed1995

Effect of methylprednisolone on metabolism and contractility in the stunned myocardium.

The effect of glucocorticoid on the metabolism and contractility in the stunned myocardium was examined by phosphorus 31 nuclear magnetic resonance (31P-NMR) in Langendorff rabbit hearts by use of an artificial blood substitute, perfluorochemical emulsion Flusol-43. After normothermic global ischemia of fifteen minutes, postischemic reperfusion of sixty-five minutes was carried out. Methylprednisolone sodium succinate (MPSS) was administered either prior to global ischemia or during postischemic reperfusion. Adenosine triphosphate (ATP), creatine phosphate (CrP), inorganic phosphate (Pi), pH, left ventricular systolic developed pressure (LV DevP) and coronary flow were continuously measured. Thirty-six hearts were divided into three experimental groups consisting of 12 hearts each; CONT consisted of controls, Pre-MPSS perfusion with MPSS-containing solution (10(-4)M) from forty-five minutes prior to global ischemia, and Post-MPSS with the same MPSS solution immediately after postischemic reperfusion. Pre-MPSS showed a significant inhibition of the increase in Pi and of the decrease in ATP and pH during global ischemia, in comparison with the other groups, and a suppression of the overshoot of CrP observed immediately after postischemic reperfusion. LV DevP of Pre-MPSS showed a marked improvement during the postischemic reperfusion as compared with CONT. In Post-MPSS, Pi was significantly increased and ATP decreased during the postischemic reperfusion as compared with the other two groups. There were no differences in coronary flow during postischemic reperfusion among the three groups. In conclusion MPSS has a beneficial effect on metabolism and contractility of the stunned myocardium when it is administered prior to ischemia.

Adenosine Triphosphate↗
PubMed1995

Regulation of cyclic AMP phosphodiesterase activity by particulate protein tyrosine kinase and phosphotyrosine phosphatase activities sensitive to sodium orthovanadate.

Sodium orthovanadate (vanadate) stimulated cAMP phosphodiesterase (PDE) and protein tyrosine kinase (PTK) activities and inhibited the phosphotyrosine phosphatase (PTPase) activity in the particulate of isolated rat fat pads. Okadaic acid never showed any increase in the PDE activity up to 1 microM. Amiloride inhibited in part both stimulations of PDE and PTK activities by vanadate. The particulate PTK activity had an optimal divalent ion requirement of 15 mM Mg+2+2 mM Mn+2 in the assay medium and was not inhibited by 1 mM N-ethylmaleimide, suggesting it to be a different type from the insulin receptor and cytosolic PTK activities. The PDE, PTK, and PTPase active fractions were separated from the solubilized particulate fraction on a DEAE-Sephacel column. PDE activity was increased by the addition of the PTK active fraction. A further increase was observed by using the PTK active fraction pretreated with 1 mM vanadate. In contrast, the addition of PTPase active fraction decreased the PDE activity. This decrease disappeared by using the PTPase active fraction pretreated with 1 mM vanadate. These results suggest that the PDE activity is in part regulated through a process involving the particulate PTK and PTPase activities sensitive to vanadate.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1995

[Fatigue and stress of anesthesiologists at work--third report: investigation with a flicker photometer and a stabilo-meter].

We previously studied the fatigue and stress of anesthesiologists at work using a flicker photometer, visual reaction time test, questionnaires, and Holter EKG. In the present study, we investigated the fatigue and stress in seven junior anesthesiologists at work using a flicker photometer and a stabilo-meter. The stabilo-meter measures postural stabilization. We performed each test three times on each subject for a total of twenty-one times. The flicker test and the stabilo-test showed the increase in fatigue in 17 (18%) and in 16 tests (76%), respectively, in all seven subjects. Increase of fatigue in both the flicker and stabilo-tests was observed in 13 tests (61%) of 6 subjects. There was a good relationship between the flicker test and the stabilo-test. Therefore, the stabilo-test appears to be a useful method for investigating the fatigue of anesthesiologists.

Anesthesiology↗
PubMed1994

Isolation of a DEAD-family protein gene that encodes a murine homolog of Drosophila vasa and its specific expression in germ cell lineage.

In an effort to study the molecular basis of the determination processes of the mammalian germ cell lineage, we have tried to isolate a mouse gene homolog to vasa, which plays an essential role as a maternal determining factor for the formation of Drosophila germ cell precursors. By reverse transcriptase PCRs of mouse primordial germ cell cDNAs using family-specific primers, we obtained a gene (Mvh) encoding a DEAD-family protein that showed a much higher degree of similarity with the product of the Drosophila vasa gene (vas) than previously reported mouse genes. In adult tissues, Mvh transcripts were exclusively detected in testicular germ cells, in which Mvh protein was found to be localized in cytoplasm of spermatocytes and round spermatids including a perinuclear granule. The protein was also expressed in germ cells colonized in embryonic gonads but was not detected in pluripotential embryonic cells such as stem cells and germ cells. These results suggest the possibility that the Mvh protein may play an important role in the determination events of mouse germ cells as in the case of Drosophila vasa.

Amino Acid Sequence↗
PubMed1994

Relationship between infectivity and OspC expression in Lyme disease Borrelia.

Borrelia burgdorferi sensu stricto strain 297 and B. garinii strains HP1 and 12-92 were serially subcultured for 36-50 passages in vitro for 1 year. All low-passage strains showed abundant expression of outer surface protein C (OspC) in the 22-23-kDa range, but the high-passage strains lost or showed reduced expression of OspC in comparison with the low-passage strains. The low-passage strains efficiently infected outbred ddY mice when inoculated into the hind footpad or peritoneal cavity. In contrast, the incidence of infection with the high-passage strains was low. Isolates from the bladders of mice inoculated with the high-passage strains expressed large amounts of OspC in comparison with those originally inoculated. These results indicate that OspC expression is related to the infectivity of Lyme disease borreliae.

Animals↗
PubMed1994

Inhibition of human sputum elastase by 7-substituted 5-methyl-2-isopropylamino-4H-3,1-benzoxazin-4-ones.

7-Substituted 5-methyl-2-isopropylamino-4H-3,1-benzoxazin-4-ones (BOZNs) were prepared and tested as inhibitors of human sputum elastase (HSE). The BOZNs with certain amino acid residues at the 7-position proved to be potent inhibitors of HSE. Some of the compounds also showed a high selectivity for HSE versus chymotrypsin. In a hamster model in which acute injury was induced by intratracheal administration of HSE (1.0 mg/kg), these compounds, when administered intratracheally (1.0 mg/kg) either 30 or even 240 min before challenge with HSE, significantly suppressed pulmonary hemorrhage. These findings suggest that 7-substitution of BOZN by amino acid residues can produce strong and HSE-specific inhibitors, with potential use in elastase-mediated disorders.

Animals↗
PubMed1994

Accessory nerve neurotization in infants with brachial plexus birth palsy.

We report the surgical results of 13 accessory nerve neurotizations in branchial plexus birth palsy. The mean age at operation was 5.9 months. The accessory nerve was transferred to three C5 roots, to three C6 roots, to four posterior division of the middle trunks, to one musculocutaneous nerve, and to two suprascapular nerves. Sixty-seven percent of the cases acquired M4 or more in the deltoid muscle, 88% in the infraspinatus muscle, and 100% in the biceps brachii muscle. Twenty-five percent of the cases acquired M4 or more in the triceps brachii muscle and the wrist extensor muscles. These results were much better than formerly reported for adult cases by other authors. No functional compromise of the trapezius muscle was noted. The accessory nerve neutrotization can be used safely and effectively in neurosurgical reconstruction of the brachial plexus palsy in infants.

Accessory Nerve↗
PubMed1994

Potentiation of oxidative damage to rat red blood cells by the concurrent presence of t-butyl hydroperoxide and bromotrichloromethane.

Recently potentiation of oxidative damage in rat red blood cells (rRBC) incubated with t-butylhydroperoxide (BHP) in combination with bromotrichloromethane (BrCCI3) was demonstrated. The mechanism by which this combination (BrCCI3/BHP) potentiates the oxidative damage to rRBC was investigated in this study. When rRBC were incubated with 0.1 mM BHP, 0.5 mM BrCCI3, or the two combined, BrCCI3/BHP-potentiated lipid peroxidation and hemolysis were further enhanced under anaerobic conditions. However, the potentiation of lipid peroxidation was abolished by heating or trypsin digestion of rRBC. Electron spin resonance (ESR) studies demonstrated an increase of alkoyl radical induced by BrCCI3/BHP in rRBC, and this increase was abolished by heating or predigestion of hemolysates with trypsin. The inhibition of lipid peroxidation by diphenylamine (which reacts with alkoxyl radicals but not peroxyl radicals) suggests an important role of alkoxyl radicals. Overall, the present findings demonstrate that the increase in radical-related oxidative damage, possibly mediated by proteinlike materials, may be at least partially responsible for the potentiation of damage to rRBC induced by BrCCI3/BHP, and perhaps by BrCCI3. Although the in vivo significance of these results remains to be investigated, it seems likely that halocarbon toxicity may be amplified by elevated levels of lipid peroxide in blood.

Animals↗
PubMed1994

Experimental induction of Lyme arthritis in outbred mice.

Outbred ddY mice inoculated with live cells of Borrelia burgdorferi strain 297 into hind footpad displayed swelling of the footpad at days 7 to 11 after inoculation. Marked neutrophilic infiltration was observed in the subcutaneous tissue and the part of bone tissue which was partially destroyed, and synovial layer of articular capsule was thickened and protruded into the joint space in the histopathological examination of footpad inoculated with live Borrelia cells. The inflammation peaked at day 7 and B. burgdorferi was cultured from bladder and heart of the mice at day 14 after inoculation. The mice inoculated with heat-inactivated cells at 56 C for 30 min did not show any significant histopathological change. In this mice model, nontreated littermates were not infected in contact with infected littermates for 14 days of experimental period. The outbred ddY mice model is useful for evaluating the effectiveness of vaccination against Lyme disease.

Animals↗
PubMed1994

Characterization of monoclonal antibodies for identification of Borrelia japonica, isolates from Ixodes ovatus.

Monoclonal antibodies for identification of Borrelia japonica isolated from tick, Ixodes ovatus and long-tailed shrew, Sorex unguiculatus in Japan and Borrelia related to Lyme disease (Borrelia burgdorferi sensu lato) were prepared and characterized. All isolates belonging to B. japonica and isolates from I. dentatus and cottontail rabbit in North America reacted with MAb O1441b against flagellin which was prepared from immunized mice with strain HO14, type strain of B. japonica, but isolates from I. persulcatus, patient, and wood mouse, Apodemus speciosus ainu, in Japan, and isolates belonging to B. burgdorferi, B. garinii and B. afzelii from North America and Europe did not. Strains used in this study reacted with MAb P62 against common antigen which was prepared from immunized mice with strain NT24 isolated from I. persulcatus in Japan, but B. japonica did not. These MAbs are useful for identification and differentiation of B. japonica and B. burgdorferi sensu lato in Japan.

Animals↗