M Nakayama

Tohoku University, Sendai, Kagoshima, Japan

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Publications (17)12.6 Total impact

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    ABSTRACT: Seedling roots display not only gravitropism but also hydrotropism, and the two tropisms interfere with one another. In Arabidopsis (Arabidopsis thaliana) roots, amyloplasts in columella cells are rapidly degraded during the hydrotropic response. Degradation of amyloplasts involved in gravisensing enhances the hydrotropic response by reducing the gravitropic response. However, the mechanism by which amyloplasts are degraded in hydrotropically responding roots remains unknown. In this study, the mechanistic aspects of the degradation of amyloplasts in columella cells during hydrotropic response were investigated by analyzing organellar morphology, cell polarity and changes in gene expression. The results showed that hydrotropic stimulation or systemic water stress caused dramatic changes in organellar form and positioning in columella cells. Specifically, the columella cells of hydrotropically responding or water-stressed roots lost polarity in the distribution of the endoplasmic reticulum (ER), and showed accelerated vacuolization and nuclear movement. Analysis of ER-localized GFP showed that ER redistributed around the developed vacuoles. Cells often showed decomposing amyloplasts in autophagosome-like structures. Both hydrotropic stimulation and water stress upregulated the expression of AtATG18a, which is required for autophagosome formation. Furthermore, analysis with GFP-AtATG8a revealed that both hydrotropic stimulation and water stress induced the formation of autophagosomes in the columella cells. In addition, expression of plastid marker, pt-GFP, in the columella cells dramatically decreased in response to both hydrotropic stimulation and water stress, but its decrease was much less in the autophagy mutant atg5. These results suggest that hydrotropic stimulation confers water stress in the roots, which triggers an autophagic response responsible for the degradation of amyloplasts in columella cells of Arabidopsis roots.
    Planta 04/2012; 236(4):999-1012. DOI:10.1007/s00425-012-1655-5 · 3.38 Impact Factor
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    ABSTRACT: Plants are sessile in nature, and need to detect and respond to many environmental cues in order to regulate their growth and orientation. Indeed, plants sense numerous environmental cues and respond via appropriate tropisms, and it is widely accepted that auxin plays an important role in these responses. Recent analyses using Arabidopsis have emphasized the importance of polar auxin transport and differential auxin responses to gravitropism. Even so, the involvement of auxin in hydrotropism remains unclear. To clarify whether or not auxin is involved in the hydrotropic response, Arabidopsis seedlings were treated with inhibitors of auxin influx (3-chloro-4-hydroxyphenylacetic acid), efflux (1-naphthylphthalemic acid and 2,3,5-triiodobenzoic acid), and response (p-chlorophenoxyisobutylacetic acid), and their effects were examined on both hydrotropic and gravitropic responses. In agreement with previous reports, gravitropism was inhibited by all the chemicals tested. By contrast, only an inhibitor of the auxin response (p-chlorophenoxyisobutylacetic acid) reduced hydrotropism, whereas inhibitors for influx or efflux of auxin had no effect. These results suggest that auxin response, apart from its polar transport, plays a definite role in hydrotropic response, and will evoke a new concept for the auxin-mediated regulation of tropisms.
    Journal of Experimental Botany 02/2007; 58(5):1143-50. DOI:10.1093/jxb/erl274 · 5.79 Impact Factor
  • N Yasumoto · M Hara · Kitamoto YU · M Nakayama · T Sato
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    ABSTRACT: The occurrence of rhabdomyolysis and acute renal failure associated with cytomegaloviral infection is rare. A 27-year-old housewife was admitted to our hospital with complaints of thirst, muscle weakness, abdominal pain and oliguria. There was no past history of diabetes, drinking, fever or drug habituation and a negative family history. Laboratory tests revealed myoglobinuria, hyper-pancreatic type amylaseuria, hyperglycemia, azotemia and highly increased creatine phosphokinase in the plasma. She was treated with hemodialysis and insulin therapy. Serological studies showed a 4-fold increase in cytomegalovirus antibody titers 4 weeks after admission. Muscle biopsy specimens showed hyaline degeneration and infiltration of T cell lymphocytes in the muscle. Renal biopsy specimens showed acute tubular necrosis and some myoglobin casts. No cytomegalovirus antigen was found in renal specimens by immunofluorescence study. From these results, it was determined that a systemic cytomegalovirus infection triggered pancreatitis which caused diabetic ketoacidosis, rhabdomyolysis and acute renal failure.
    Internal Medicine 04/1992; 31(3):426-30. DOI:10.2169/internalmedicine.31.426 · 0.97 Impact Factor
  • M Tomita · Y Kitamoto · M Nakayama · T Sato
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    ABSTRACT: A new morphological classification of urinary erythrocytes was instituted in order to differentiate glomerular from urological hematuria. One hundred and thirteen hematuric patients including 73 glomerular and 40 urological disease patients were examined. The former group consisted of IgA nephropathy (n = 45), lupus nephritis (6), membrano-proliferative glomerulonephritis (5), non-IgA mesangial proliferative glomerulonephritis (4), Henoch-Schoenlein purpura nephritis (4), membranous nephropathy (4), endocapillary proliferative glomerulonephritis (3), and minimal change nephrotic syndrome (2). The latter group included bladder cancer (n = 15), renal calculi (15), prostate cancer (3), urethral cancer (1) and post-transurethral resection (6). In each urine sample, 100 urinary erythrocytes were observed under differential interference microscopy and classified into 10 concretely defined shapes (5 "glomerular" and 5 "urological" shapes) and unclassified shapes. Using percentage of "glomerular" shape erythrocytes and setting the cut-off at 15%, 90.4% of sensitivity and 97.5% of specificity for the diagnosis of glomerular disease were obtained. When percentage of one specific shape (G1), [i.e. doughnut-like cell with one or more blebs] was used at a cut-off of 1%, sensitivity and specificity were 89.0% and 95.0% respectively. These results were satisfactory as compared with most previous reports. Moreover, our classification is so concrete that it is more objective, accurate, and easily understandable, even for beginners. Distinct shape "G1" is particularly important for morphological investigation of hematuria.
    Clinical nephrology 03/1992; 37(2):84-9. · 1.23 Impact Factor
  • M Akamine · M Tomita · T Inoue · Y Kitamoto · M Nakayama · T Sato
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    ABSTRACT: Although the etiology of systemic lupus erythematosus (SLE) is thought to be multifactorial, genetic factors may play some role in its pathogenesis. Supportive of this hypothesis are the studies of identical twins and familial cases of SLE. We describe below a family in which mother and son both developed SLE. The mother was diagnoged as SLE at age 25, and had been treated with prednisolone. In February 1989, she had massive proteinuria. The onset of the son's disease was at age 13 in 1988, when he noted erythema and photosensitivity. At admission to our hospital in 1989, he had polyarthralgia, proteinuria, positive antinuclear antibody, positive anti-DNA antibody. Both two patients had a same haplotype, HLA A2.BW61(40).DR9. Two asymptomatic members of this family were also studied, the younger son had positive antinuclear antibody and hypocomplementemia.
    Nippon Jinzo Gakkai shi 07/1991; 33(6):623-8.
  • S Kiyama · Y Kitamoto · M Nakayama · H Fukui · S Arima · M Tomita · T Inoue · T Sato
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    ABSTRACT: The renal disease in an adult woman with Type 1 glycogen storage disease (GSD) is reported. Since she was 15 years old, several episodes of gouty arthritis had developed. At the age of 18, proteinuria was pointed out. Hepatomegaly, renomegaly out of proportion to the impairment of renal function, hyperuricemia, hyperlipidemia, fasting hypoglycemia and lactic acidemia were observed. The diagnosis of GSD was established on the basis of a glucose tolerance test, glucagon test and liver biopsy. The findings of renal biopsies performed at the ages of 24 and 27 years old suggested that glomerular damage might have preceded the tubulo-interstitial lesion.
    Nippon Jinzo Gakkai shi 02/1991; 33(1):81-5.
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    ABSTRACT: A 54 year-old woman who had had 4 years history of ulcerative colitis (UC) was admitted to our hospital because of recently developed proteinuria and leg edema. On admission, laboratory findings disclosed massive proteinuria, hypoalbuminemia, acceleration of ESR and elevated of CRP. Her abdominal symptom was remitted. Renal biopsy showed amyloid deposition in glomeruli and arteriole. Amyloid deposition was also found on rectal biopsy. She had no evidence of familial amyloidosis and multiple myeloma. In this case, amyloid deposition might be developed after UC. Secondary amyloidosis due to UC was extremely rare, only 3 cases including ours were reported in Japan.
    Nippon Jinzo Gakkai shi 05/1990; 32(4):435-9.
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    ABSTRACT: Two patients with IgA nephritis associated with hereditary plasminogen abnormalities are described. One patient had dysplasminogenemia and the other had plasminogen deficiency. In both patients, renal biopsy specimens showed significant arteriosclerotic changes in addition to mesangial proliferation. Increased fibrinopeptide A concentration in their plasma suggested increased thrombin generation. In one patient, no systemic arteriosclerosis coexisted, judging from normal optic fundi and the absence of neurological and cardiac abnormalities. In IgA nephritis, renal vascular hyalinosis is often observed, probably resulting from vascular injury. Thus, it was suggested that the decreased fibrinolysis and renal vascular injury of these patients synergistically induced more fibrin thrombi and accelerated arteriosclerosis of the kidney. These cases imply the important role of fibrinolytic disorders in the progression of IgA nephritis.
    Clinical nephrology 03/1990; 33(2):61-5. · 1.23 Impact Factor
  • S Naomi · T Umeda · T Iwaoka · F Miura · M Sasaki · M Nakayama · Y Kitamoto · T Sato
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    ABSTRACT: To clarify the molecular nature and dynamics of circulating alpha human atrial natriuretic polypeptide (alpha hANP) in chronic renal disease, the plasma concentrations of alpha hANP were determined by radioimmunoassays using two distinct monoclonal antibodies (MoAbs). One MoAb (10B1) recognized N-terminus of alpha hANP, while the other (C351) recognized the ring structure. The preliminary studies revealed a close correlation (r = 0.97, p less than 0.0001) between plasma alpha hANP measured with 10B1 and C351 MoAbs, supporting the theory that the main circulating form is alpha hANP(1-28). Therefore, the more sensitive radioimmunoassay using MoAb (C351) was used in the present studies. The plasma alpha hANP was 3.8 +/- 1.7 (mean +/- SD) in healthy subjects, 2.7 +/- 1.4 fmol/ml in patients with chronic glomerulonephritis without renal failure, 16.2 +/- 16.8 fmol/ml in patients with chronic renal failure, and 24.3 +/- 10.5 fmol/ml in patients under maintenance hemodialysis. Thus, the elevation of plasma alpha hANP was related to the stages of renal damage. Although the plasma alpha hANP in 18 patients under maintenance hemodialysis declined significantly (p less than 0.01) after hemodialysis, their levels (17.9 +/- 9.0 fmol/ml) after hemodialysis were still higher than those in healthy subjects. On the other hand, a positive correlation (r = 0.65, p less than 0.05) between alpha hANP and creatinine in blood was found only in the group of chronic renal failure before maintenance hemodialysis. These results suggest that an impaired metabolism of alpha hANP in the kidney might play an important role in the elevation of plasma alpha hANP as well as the stimulation of alpha hANP secretion caused by the expansion of extracellular fluid.
    Nippon Naibunpi Gakkai zasshi 04/1989; 65(3):152-60.
  • M Hara · S Kimura · N Ikezaki · M Nakayama · T Sato
    Nippon Jinzo Gakkai shi 09/1987; 29(8):989-94.
  • N Tazoe · N Ikezaki · J Ito · K Kuwahara · M Hara · M Nakayama · T Sato
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    ABSTRACT: Recently, acute interstitial nephritis (AIN) presenting nephrotic syndrome and renal failure induced by nonsteroidal anti-inflammatory drug (NSAID) has been recognized with increasing frequency. We described here a 43-year-old woman who developed this type of nephropathy after taking NSAID for rheumatoid arthritis. Flurbiprofen (Froben) was assumed to be a causal drug based on a clinical course and a positive result of lymphocyte transformation test. Withdrawal of flurbiprofen therapy led no sufficient improvement, and high-dose steroid therapy done 15 months after the onset resulted in only a minor improvement. So far as we know, this was the second case of AIN associated with flurbiprofen and the youngest in NSAID-induced AIN with irreversible chronic renal insufficiency.
    Japanese journal of medicine 06/1987; 26(2):230-3. DOI:10.2169/internalmedicine1962.26.230
  • J Ito · N Tazoe · K Kuwahara · M Hara · H Miura · M Nakayama · T Sato
    Nippon Jinzo Gakkai shi 05/1987; 29(4):409-15.
  • ASAIO transactions / American Society for Artificial Internal Organs 01/1987; 33(3):136-9.
  • M Nakayama · M Hara · K Kuwahara · H Miura · N Tazoe · J Ito
    Nippon Jinzo Gakkai shi 07/1985; 27(6):859-63.
  • H Miura · N Tazoe · M Hara · K Kuwahara · J Itoh · M Nakayama
    Nippon Jinzo Gakkai shi 04/1984; 26(3):337-42.
  • H Miura · M Nakayama · K Kuwahara
    Nippon Jinzo Gakkai shi 10/1982; 24(9):955-63.
  • T Iwaoka · T Umeda · M Nakayama · T Shimada · Y Fujii · F Miura · T Sato
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    ABSTRACT: A 54-year-old woman who had proteinuria due to stage II membranous nephropathy is reported. She was treated with indomethacin for proteinuria and developed drug-induced hepatitis four months later. Liver dysfunction gradually recovered, but hormonal studies revealed abrupt fall of T3 and T4 and concomitant elevation of TSH levels within a month. Pathological findings of thyroid specimen and positive antithyroglobulin and antimicrosomal antibodies were compatible to chronic thyroiditis. In the second renal biopsy, glomerular deposits of thyroglobulin, thyroid microsomal antigens and IgG were demonstrated by immunofluorescence. Therefore, membranous nephropathy in this patient is presumed to be caused by immune complexes mediated by thyroid constituents. We believe that this is a precious case because continuous changes in T3, T4 and TSH were followed in a course of chronic thyroiditis, especially in the stage of progress to hypothyroidism, and the chronic thyroiditis was shown to be involved in the membranous nephropathy.
    Japanese journal of medicine 02/1982; 21(1):29-34. DOI:10.2169/internalmedicine1962.21.29