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N Anzai

Publications and source records attributed to N Anzai.

At least 37 records · Page 2Linked to original sources
PubMed1997

Potassium transport and potassium channels in the kidney tubules.

A variety of K+ channels have been identified using electrophysiological techniques including the patch-clamp method. The types of channels include inwardly-rectifying, ATP-dependent, Ca(2+)-dependent, voltage-gated, and so on. Some of them have been cloned by expression and/or PCR cloning techniques, which give us their amino-acid sequences and molecular topology in the cell membrane. Immunohistochemical studies have shown the proteins (channels) to be localized to the luminal and/or basolateral membranes of a certain nephron segment. However, the relationships of these proteins with the ionic channels identified functionally must be examined by their reconstitution in cell-free systems (lipid bilayer membrane) and/or their expression in cells lacking native K+ channels. Much more care should also be taken to avoid artifacts due to channel-inducing factors (CHIF). Structure-function studies at the molecular level will advance our knowledge of the renal K+ channels and provide us with a further understanding of the role of the kidney in K+ homeostasis.

Animals↗
PubMed1997

Apoptosis as a cell biological abnormality in myelodysplasia.

Evidence is accumulating to indicate that alterations in the control of apoptosis can contribute to a variety of disorders. Among the disorders associated with abnormal regulation of apoptosis, MDS stands out unequaled in that apoptosis is related, in apparently opposite directions, to ineffective hematopoiesis and leukemic transformation of MDS; notably, excessive apoptosis in the former and deranged apoptosis or escape from apoptotic control in the latter. In this review, we want to focus on the role of apoptosis in various stages of MDS, and to discuss its possible relevance to further therapeutic interventions.

Acute Disease↗
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↗
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

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

Effect of the medication management module evaluated using the role play test.

Training in social skills has been shown to have a strong, positive impact, according to behavioral measures, on social skills, self-rated assertiveness, and the hospital discharge rate. It is important to establish a system of assessing social skills because it is necessary for the effects of social skills training to be assessed in Japan. In Project 1, we devised a Japanese version of the role play test to quantify social skills using a standard method. We tested 30 patients attending the day hospital who were considered to need intensive rehabilitation. We found the role play test had high inter-rater and test-retest reliability, and had construct validity and criterion related validity. Thus, the role play test was thought to be a useful tool for assessing social skills. For Project 2, eight inpatients who were ready for discharge but who needed to improve their skills in self-managed medication participated in this study. The social skills of self-managed medication assessed using the role play test were significantly improved after the subjects participated in the Medication Management Module of the UCLA social and independent living skills program. Knowledge of self-managed medication also tended to improve after training. This study is preliminary and it should be confirmed that improved skills influenced by the medication management module decreases the relapse rates.

Adolescent↗
PubMed1995

[Primary culture of proximal tubular cells (PTC) from normal mouse kidney as an in vitro model to study mechanisms of development of tubulointerstitial nephritis. Induction of ICAM-1 in PTC by antigen-primed lymphocytes].

Cultured PTC clearly expressed intercellular adhesion molecule-1 (ICAM-1) under the influence of tubular basement membrane antigen (TBM)-primed lymphocytes. These TBM-primed lymphocytes also demonstrated a high cytotoxic activity against cultured PTC. A pure preparation of isolated PTC from BALB/c mouse kidney was brought into primary culture. PTC was prepared by the method of Boogaard PJ et al, and our modification. Briefly, kidney was perfused with buffer containing 0.08% (w/v) collagenase. The cortical tissue was then filtered through nylon-gauze. Viable PTC were separated from other materials by isopycnic centrifugation on a discontinuous Nycodenz gradient. The confluent monolayer of PTC showed a typical epithelial morphology with cobblestone-like cells in the center of the cell-islands. Typical dome formation was observed in PTC cultures. These cells also strongly expressed gamma-glutamyl transpeptitase activity. Coculture of PTC with syngeneic lymphocytes primed with TBM antigen induced ICAM-1 expression in PTC. The TBM-primed lymphocytes had a cytotoxic activity without complement. However, neither virgin lymphocytes nor liver antigen-primed lymphocytes had cytotoxic activity. This simple syngeneic experimental model may allow us further molecular biological examination of renal tubulointerstitial diseases.

Animals↗
PubMed1994

A new method for quantitative estimation of the degree of DNA fragmentation utilizing agarose gel electrophoresis.

We designed a new method for quantitative analysis of the degree of DNA fragmentation, a characteristic feature of apoptosis. A photograph of an agarose gel electrophoresis of fragmented DNA was incorporated by an optical density scanner or equivalent equipment, and the integrations of middle molecular size area (10,000 to 300 bp), single nucleosomal size area (smaller than 300 bp) and total lane area were calculated. We defined fragmentation rate or (%)FR as the amount of fragmented DNA expressed as the percentage of the total amount of DNA, assigning the coefficients of 1 and 0.5, respectively, to the fragments completely digested into single nucleosomal length and to those partially digested (between 10 k to 300 bp). A standard calibration curve was constructed from triplicate experiments of target nuclei digestion by micrococcal nuclease, which revealed that this method covered a wide range of nuclease activity. We also confirmed that our method was applicable to an autodigestion assay of isolated nuclei which represented endogenous endonuclease activities. This method may be a useful tool for quantitative analysis of endonuclease activities capable of producing nucleosomal-size DNA fragmentation.

Apoptosis↗
PubMed1994

Marked apoptosis of human myelomonocytic leukemia cell line P39: significance of cellular differentiation.

Myelodysplastic syndrome (MDS)-derived leukemia cell line P39/Tsugane could be induced to apoptosis by a variety of agents including metabolic inhibitors, a calcium ionophore and differentiation-inducing agents. As evaluated by characteristic morphological changes and oligonucleosomal lengths DNA ladder, the levels of apoptosis in P39 cells induced by actinomycin D, or A23187, were far greater than in other myeloid lines examined in this study. When 22-oxa-1 alpha, 25(OH)2D3 (D3), dimethyl sulfoxide (DMSO) and all-trans retinoic acid (RA) were used as differentiation-inducers, varying degrees of apoptosis were seen. D3 induced monocytoid differentiation, but not apoptosis above the control level. On the other hand, RA induced profound apoptosis concomitant with the progressive expression of differentiation markers. Studies on morphology, functions and phenotypes of P39 cells exposed to differentiation inducers suggest that the incidence of apoptosis was not affected by the process of differentiation, but cells in the process of varying degrees of differentiation may die via apoptosis. Moreover, RA-treated P39 cells are unique in the simultaneous occurrence of profound apoptosis and differentiation. We propose that RA-treated P39 differentiation model is ideally suited for the study of MDS.

Apoptosis↗
PubMed1994

[Assessment of social disability of patients suffering from chronic mental illness with the role play test].

UNLABELLED: Among the chronic mentally ill patients, disabilities invade most parts of their social functioning, and influences their long term course profoundly. It is important clinical issue to improve disability. Social skills training is assumed to be effective method to improve disability, and it has been disseminated over Japan recently. The assessment system to evaluate disabilities objectively at the viewpoint of social skills must be required to verify effects of social skills training, and to develop further effective therapeutic method. A role play test is the assessment tool for social skills through role plays under specific social conditions. It was reported to be useful as the method of functional assessment before treatment, and as the tool to evaluate effects of treatment to improve disability. PURPOSE: We created the Role Play Test (RPT) which was adapted to Japanese cultural background, and we tried to verify feasibility, reliability, and validity of the RPT. SUBJECTS: Thirty out-patients attending in the Day Hospital attached to Tokyo University Hospital. Twenty-six were schizophrenia, and 4 were other diagnoses. METHOD: Subjects were assessed with the RPT, BPRS, SANS, four rating scales for social functioning, and self-efficacy rating scale. The RPT was designed to assess components of social skills--social perception, role play behavior, and self-efficacy. Role play behaviors were recorded with video tapes for analysis of interrater reliability. The RPT is consisted of 12 scenes to evaluate social skills which are required in daily life. Statistical analyses were done with SAS (Statistical Analysis System). RESULTS: (1) The RPT was presumed to be feasible clinically, because the RPT could be practiced easily and responsibilities of both subjects and testers were not so much. (2) Interrater reliabilities assessed with ANOVA-ICC on 12 items was sufficiently high except one item. (3) Construct validity was certified through factor analysis, and criterion-related validity was certified through correlation analysis with other rating scales of social functioning. (4) Individual profile of the RPT should be useful instrument for functional analysis before social skills training. We also discussed on some hypotheses on the causal relationship between positive and negative symptoms and social skills. The RPT could be used as a tool to research causes of disabilities, and to evaluate improvement of social functioning after psycho-social intervention including social skills training, because the RPT can assess social skills quantitatively according to the cognitive-behavioral model.

Adolescent↗
PubMed1993

Detection of Mg(2+)-dependent endonuclease activity in myeloid leukemia cell nuclei capable of producing internucleosomal DNA cleavage.

We detected Mg(2+)-dependent, Ca(2+)-independent endonuclease activity in non-apoptotic myeloid leukemia cell nuclei using autodigestion method which cleaved the chromatin of the autologous leukemia cells to an oligonucleosomal length pattern. Similar endonuclease activity could be successfully recovered in the protein extracts of the human leukemia cell nuclei. The extracts consistently elicited characteristic DNA cleavage of another leukemia cell (KG-1) nuclei as the target, the enzyme activity of which had been inactivated. We propose that this method is a useful tool for the study of endonucleases involved in apoptosis.

Animals↗
PubMed1993

Serial changes in endogenous erythropoietin levels in patients with myelodysplastic syndromes and aplastic anemia undergoing erythropoietin treatment.

Recombinant human erythropoietin (rhEpo) was administered to 14 patients with myelodysplastic syndrome (MDS) and seven patients with aplastic anemia (AA). In 19 patients, doses of 6000 units were given intravenously three times a week (t.i.w.) with the dose being doubled up to 24,000 units every 8 weeks until a response was obtained. RhEpo was given subcutaneously in two patients. Seven patients, four with MDS and three with AA, showed a significant response with an increase of hemoglobin concentration during therapy. The response occurred at doses of 12,000 units in five and 24,000 units in two patients. Responding patients with both MDS and AA had a relatively low serum Epo (s-Epo) level prior to Epo therapy. MDS responders had either refractory anemia (RA) or RA with ring sideroblasts (RARS), while two of the Epo responders in AA had a severe form of the disease. However, since some of the Epo responders had a high initial s-Epo concentration, a high s-Epo level does not preclude the use of rhEpo. Serial determination of s-Epo levels showed a progressive decline in six of the seven responders even when they were on rhEpo therapy, while the s-Epo levels remained elevated or further increased with time in most nonresponders. RhEpo was well tolerated by all patients. The results suggest that rhEpo is a safe and effective treatment for a certain proportion of patients with MDS and AA. Moreover, serial determination of s-Epo during therapy may be useful in monitoring and predicting the therapeutic effect of rhEpo.

Adolescent↗