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S Hisanaga

Publications and source records attributed to S Hisanaga.

At least 73 records · Page 4Linked to original sources
PubMed1992

Activation of ATPase activity of 14S dynein from Tetrahymena cilia by microtubules.

The ATPase activity of 14S dynein was activated by the presence of microtubule-associated-protein-free microtubules. The activation was 2.5-3.5 fold at 10 mg microtubule/ml, and the activity increased further with increasing microtubule concentration. The microtubule-14S-dynein complex, microtubule bundles with 14S dynein, was treated with a zero-length chemical cross-linker, 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide (EDC). The ATPase activity of the complex responded to EDC in a biphasic, concentration-dependent manner and, at most, it was enhanced 5-10 fold. The complex treated with EDC was no longer unbundled by addition of ATP, as revealed by electron-microscopic observation. Several ATP analogues, which support in vitro microtubule translocation mediated by 14S dynein, were turned over faster by this mechanochemical enzyme in the presence of microtubules than in their absence. However, some ATP analogues which do not support the translocation were also turned over faster in the presence of microtubules. Thus, microtubule-dynein motility and substrate-turnover activation are not tightly coupled, which indicates that all three major motor systems, actin- heavy-meromyosin, microtubule-kinesin [Shimizu, T., Furusawa, K., Ohashi, S., Toyoshima, Y. Y., Okuno, M., Malik, F. & Vale, R. D. (1991) J. Cell Biol. 112, 1189-1197] and microtubule-dynein, have this characteristic property in common.

Adenosine Triphosphatases↗
PubMed1992

Relocation and distinct subcellular localization of p34cdc2-cyclin B complex at meiosis reinitiation in starfish oocytes.

M phase promoting factor (MPF) is a major element controlling entry into the M phase of the eukaryotic cell cycle. MPF is composed of two subunits, p34cdc2 and cyclin B. Using indirect immunofluorescence staining with specific antibody against starfish cyclin B, we monitored the dynamics of the subcellular distribution of MPF during meiosis reinitiation in starfish oocytes. We found that all of the cyclin B is already associated with p34cdc2 in immature oocytes arrested at the G2/M border and that this inactive complex is present exclusively in the cytoplasm. After its activation, part of the p34cdc2-cyclin B complex moves into the germinal vesicle before nuclear envelope breakdown, independently of either microtubules or actin filaments. Thereafter, some part of the complex accumulates in the nucleolus and condensed chromosomes. Another portion of the complex accumulates on meiotic asters and spindles, while the rest is still present throughout the cytoplasm. As these patterns of localization are detected in the detergent-extracted oocytes, we propose at least four distinct subcellular states of the p34cdc2-cyclin B complex: freely soluble, microtubule-associated, detergent-resistant cytoskeleton-associated and chromosome-associated. Thus, in addition to the intramolecular modification of p34cdc2-cyclin B complex, its intracellular relocation plays a key role in promoting the M phase.

Animals↗
PubMed1992

The 72-kDa microtubule-associated protein from porcine brain.

A microtubule-associated protein (MAP) with a molecular mass of 72-kDa that was purified from porcine brain by using its property of heat stability in a low pH buffer was characterized. Low-angle rotary shadowing revealed that the 72-kDa protein was a rodlike protein approximately 55-75 nm long. The 72-kDa protein bound to microtubules polymerized from phosphocellulose column-purified tubulin (PC-tubulin) with taxol and promoted the polymerization of PC-tubulin in the absence of taxol. Microtubules polymerized by the 72-kDa protein showed a tendency to form bundles of several microtubules. Quick-freeze, deep-etch electron microscopy revealed that the 72-kDa protein formed short crossbridges between microtubules. We performed peptide mapping to analyze the relationship of the 72-kDa protein to other heat-stable MAPs, and the results showed some resemblance of the 72-kDa protein to MAP2. Cross-reactivity with a monoclonal anti-MAP2 antibody further suggested that the 72-kDa protein and MAP2 are immunologically related. To study the relationship between the 72-kDa protein and MAP2C, a smaller molecular form of MAP2 identified in juvenile rat brain, we prepared the 72-kDa protein from rat brain by the same method as that used for porcine brain. The fact that the 72-kDa protein from juvenile rat brain was also stained with our monoclonal anti-MAP2 antibody also suggested that the 72-kDa protein is an MAP2C homologue of the porcine brain.

Animals↗
PubMed1992

Ultrastructure of detergent-resistant cytoskeletons in the noncortical domain of sea urchin eggs as revealed by the quick-freeze deep-etch technique.

The ultrastructure of detergent-resistant cytoskeletons in the noncortical cytoplasm of sea urchin eggs was studied by quick-freeze, deep-etch electron microscopy. Two different cytoskeletal organizations were identified in the detergent-treated sea urchin eggs. They were distinguished by the presence or the absence of long actin filaments and probably correspond to the cortex and the noncortical cytoplasm, respectively. The non-cortical cytoplasm was composed of a complex network (designated here as the ground network) of filaments 6 to 13 nm in diameter, that interconnected aggregates of small globular materials, yolk granules and a meshwork of uniform filaments (8-9 nm in diameter). The 6 to 13 nm filaments comprising the ground network were branched and associated with filaments of the same or other sizes, resulting in the formation of an extremely complex network. The meshwork of 8-9 nm filaments was homogeneous in composition and constitutes a novel structure which has not been previously described. The 8-9 nm filaments were connected to one another at their ends, forming a meshwork of polygons. Meshworks, ranging up to 3 microns in diameter, were distributed throughout the non-cortical cytoplasm of the egg. Similar cytoplasmic structures were also observed in fertilized eggs.

Actins↗
PubMed1992

[Etoposide and cisplatin combination chemotherapy in a patient with small cell lung carcinoma under artificial hemodialysis].

A 70-year-old man with small cell carcinoma of the lung who was under artificial hemodialysis, was treated by combined administration of etoposide and cisplatin. Fifty mg. of etoposide in combination with 35 mg. of cisplatin were infused before dialysis. Before one hour and during dialysis, plasma etoposide and platinum levels decreased rapidly. No severe side effect was observed after the administration of etoposide and cisplatin. In conclusion, it was considered that cisplatin and etoposide could be given to the patient with malignant tumor under artificial hemodialysis.

Aged↗
PubMed1992

[Investigation of the incidence of aberration in various indication for prenatal cytogenetic analysis].

In order to evaluate the role of prenatal cytogenetic analysis for the management of pregnant women, we studied the incidence of chromosomal aberration in 1,258 cases. In 502 cases with advanced maternal age (at least 35 years older), 12 (2.4%) cases of chromosome aberration were detected. The incidence of chromosomal aberration in the cases with women who had a previous child with chromosome aberration, women who had given birth to a congenital malformation child, and women who had ultrasonographic abnormalities were 3.0% (8/271), 0% (0/103) and 11.7% (36/307), respectively. Of cases with advanced maternal age, the incidence of chromosome aberration is 0% (0/21) at age 35, 0% (0/22) at age 36, 19% (1/52) at age 37, 2.2% (2/92) at age 38, 10% (1/102) at age 39, 1.3% (1/75) at age 40, 5.3% (3/56) at age 41, 6.9% (3/43) at age 42, 4.4% (1/23) at age 43 and 6.7% (1/15) at age 44. These results indicate that the incidence of chromosome aberration increases with maternal age. On the basis of these data, we recommend medical practice to offer prenatal diagnosis to all women who will be 37 or older. In the cases of fetal anomaly, they were diagnosed by ultrasonographic examination, the high incidence of chromosome aberration was detected in comparison with another group. Therefore, the prenatal cytogenetical analysis may also be performed in these cases.

Adult↗
PubMed1991

Phosphorylation of neurofilament H subunit at the tail domain by CDC2 kinase dissociates the association to microtubules.

We sought the mammalian neurofilament tail domain-specific kinase. Several well known kinases including cAMP-dependent protein kinase, protein kinase C, Ca(2+)-calmodulin-dependent protein kinase II, casein kinase I, and casein kinase II phosphorylated the high (NF-H) and middle molecular mass subunit (NF-M) of bovine neurofilaments, but they did not reduced the electrophoretic mobility of the dephosphorylated form of NF-M and NF-H by phosphorylation nor was the amount of phosphorylation increased by dephosphorylation of NF proteins, indicating that the phosphorylation sites by these kinases are not major in vivo phosphorylation sites at the tail domain. In contrast, cdc2 kinase phosphorylated specifically the dephosphorylated form of NF-H. 4 mol of phosphates were incorporated per mol of NF-H and this phosphorylation returned the electrophoretic mobility of the dephosphorylated form of NF-H to the position of the isolated, fully phosphorylated form of NF-H. Furthermore, the phosphorylation by cdc2 kinase dissociated the binding of dephosphorylated NF-H to microtubules. Phosphorylation sites were located at the carboxyl-terminal tail domain. The KSPXK motif, but not KSPXX, in the repetitive sequence was suggested to be the phosphorylation site by using synthetic peptides.

Amino Acid Sequence↗
PubMed1991

Tertiary hyperparathyroidism associated with metastatic cardiac calcification in a haemodialyzed patient.

A 32-year-old man undergoing haemodialysis treatment for 10 years was referred to our hospital because of intractable heart failure with atrioventricular block. On the 5th hospital day he was found dead in bed. Autopsy revealed extensive metastatic calcification involving the myocardium and the cardiac conduction system, and a parathyroid adenoma with hyperplastic parathyroid glands. Retrospectively, first-degree heart block developed 14 months before death, and was subsequently associated with intraventricular conduction defect and atrioventricular block (Wenckebach type). Throughout the 3 years the patient received 1 alpha-hydroxycholecalciferol (1 alpha-OH-D3) and the calcium-phosphorus product (Ca X P) exceeded 70. 1 alpha-OH-D3 should not be prescribed when patients develop an increase in Ca X P and exploration of the parathyroid glands should not be delayed if heart block presents in long-term haemodialyzed patients.

Adenoma↗
PubMed1991

Minimal change nephrotic syndrome in adults: response to corticosteroid therapy and frequency of relapse.

Rate of response to a corticosteroid and frequency of relapse were studied in 33 patients with adult-onset minimal change nephrotic syndrome (MCNS). Of these, 28 patients were treated with oral prednisolone (PSL) at 1 mg/kg/d for from 4 to 8 weeks depending on their response, followed by PSL, at gradually tapering doses for 1 year. Five severely nephrotic patients received 1 g of methylprednisolone intravenously (IV) for 3 days, followed by 40 mg/d oral PSL for 4 to 8 weeks and finally PSL in gradually reduced doses. Sixteen patients (48%) were free of proteinuria within 4 weeks, and 25 (76%) within 8 weeks. Two patients required cyclophosphamide for induction of remission. Age at presentation was not significantly correlated with response time to corticosteroid therapy. Thirty-two (97%) went into remission, and relapse occurred in 11 (34%) of these. As assessed by the life-table method, 84% of patients were still in remission at 6 months after induction of remission, 75% after 1 year, and 63% during the follow-up period (mean, 47.1 +/- 29.1 months; range, 6 to 123 months). Incidence of relapse was not correlated with remission induction time, ie, earlier (less than or equal to 4 weeks) or later (greater than 4 weeks), but was greater in younger (less than 30 years of age) patients than older (greater than or equal to 30 years) patients (P less than 0.03). At the last follow-up, 31 patients (94%) were in complete remission and had normal renal function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Renal tubular lesions induced by human Bence Jones protein in the rat: N-acetyl-beta-D-glucosaminidase as a sensitive marker.

The renal tubular lesion induced by human Bence Jones proteins (BJPs) in the rat was investigated to elucidate the initial role of BJPs in the genesis of renal tubular damage in myeloma kidney. Human BJP extracted from the urine collected from a patient with lambda light chain myeloma was given intraperitoneally to Sprague-Dawley rats with a daily dose of 300 mg/day for 5 days (BJP group, n = 16). Daily urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG), which may represent the intensity of tubular damage, was measured. On days 10 and 20 after start of the injection, the kidneys were removed and examined by light and electron microscopy. The renal content of NAG was also measured to estimate the lysosomal activity. Both urinary and renal tissue NAG were significantly higher in the BJP group than in control rats injected with bovine serum albumin (n = 16). The most characteristic changes were found in the proximal tubules of the BJP group; the number and size of lysosomes were increased, and some showed enlargement with autophagic vacuolation. However, these were not found in the control group. There were no obvious changes in the distal tubules in either group, and the glomeruli appeared to be intact. These results suggest that BJP directly damages the proximal tubules via the process of catabolism, resulting in injury to these cells, and that the urinary NAG is a sensitive marker to detect early tubular damage by BJP.

Acetylglucosaminidase↗
PubMed1991

[Clinicopathologic study of adult-onset membranoproliferative glomerulonephritis].

We analyzed clinicopathologic characteristics of adult-onset membranoproliferative glomerulonephritis (MPGN) by comparing two tentatively-classified subgroups. Group A consisted of 9 patients in whom more than 50% of glomeruli showed mixed segmental and global duplication of glomerular basement membrane (GBM), and Group B 9 patients with global duplication of GBM. Group A showed a tendency for more favorable clinical course and outcome than Group B. Nephrotic syndrome was present in 33% of Group A and 100% in Group B, hypertension in 22% and 44%, hypocomplementemia in 44% and 67% at the time of renal biopsy. Deterioration of renal function, at comparable durations of follow-up of 62 +/- 12 (M +/- SE) and 53 +/- 13 months, was observed in 22% of Group A and 56% in Group B, respectively. Histologically, mesangial proliferation and tubulointerstitial change were more pronounced and frequency of sclerosing glomeruli was greater in Group B. There was also a negative correlation between the extent of global double contour and renal function as assessed by creatinine clearance at the time of renal biopsy (r = -0.55, P less than 0.05). These results indicate that the high incidence of global double contour, in addition to the presence of marked tubulointerstitial change and sclerosing glomeruli, may relate to progressive deterioration of renal function in MPGN. That outcomes for Group A and Group B may be different when clinical parameters, including the durations from onset of symptoms to the time of biopsy and length of follow-up periods, are comparable also indicates that these two groups should be considered separate entities, at least on the basis of clinical results.

Adolescent↗
PubMed1990

Dephosphorylation-induced interactions of neurofilaments with microtubules.

Effects of dephosphorylation on interactions of neurofilaments (NFs) with microtubules (MTs) were studied by the cosedimentation method. Centrifugation conditions were chosen so that MTs pelleted but NFs did not. While NFs isolated from bovine spinal cords did not cosediment with MTs polymerized in the presence of taxol, NFs dephosphorylated with Escherichia coli alkaline phosphatase began to coprecipitate with MTs. The dephosphorylated NFs bound to MTs but not to the unpolymerized tubulin dimer. The binding was not observed in the presence of high salt or with MTs containing microtubule-associated proteins. The cosedimentation experiments using purified NF subunit proteins showed that the dephosphorylation-induced binding of NFs to MTs was mediated by the largest subunit of NF (NF-H). Negative staining electron microscopy confirmed bindings of the dephosphorylated NFs and NF-H to MTs. Densitometric measurement of the bound and unbound NF-H after sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the binding of the dephosphorylated NF-H to MT was saturable and gave the following binding parameters. Approximately 1 mol of NF-H bound per 10 mol of tubulin dimer with a high affinity site (Kd = 3.8 x 10(-8) M) and per 16 mol of tubulin dimer with a low affinity site (Kd = 1.1 x 10(-7) M).

Animals↗
PubMed1990

Molecular architecture of the neurofilament. I. Subunit arrangement of neurofilament L protein in the intermediate-sized filament.

Using the smallest subunit (NF-L) of a neurofilament and a glial fibrillary acidic protein, the subunit arrangement in intermediate filaments was studied by low-angle rotary shadowing. NF-L formed a pair of 70 to 80 nm rods in a low ionic strength solution at pH 6.8. Two 70 to 80 nm rods appeared to associate in an antiparallel manner with an overlap of about 55 nm, almost the same length as the alpha-helix-rich central rod domain of intermediate filament proteins. The overlap extended for three-beaded segments, present at 22 nm intervals along the pairs of rods. The observations that (1) 70 to 80 nm rods were a predominant structure in a low ionic strength solution at pH 8.5, (2) the molecular weights of the rod and the pair were measured by sedimentation equilibrium as 190,000 and 37,000 respectively, and (3) the rods formed from the trypsin-digested NF-L had a length of about 47 nm, indicated that the 70 to 80 nm rod is the four-chain complex and the pair of rods is the eight-chain complex. Similar structures were observed with glial fibrillary acidic protein, indicating that these oligomeric structures are common to other intermediate filament proteins. NF-L assembled into short intermediate-sized filaments upon dialysis against a low-salt solution containing 1 to 2 mM-MgCl2 at 4 degrees C. The majority of these short filaments possessed four or five-beaded segments, suggesting that the pair of rods were arranged in a half-staggered fashion in neurofilaments. On the basis of these observations, we propose the following model for the intermediate filament subunit arrangement. (1) The four-chain complex is the 70 to 80 nm rod, in which two coiled-coil molecules align in parallel and in register. (2) Two four-chain complexes form the eight-chain complex by associating in an antiparallel fashion with the overlap of the entire central rod domain. (3) The eight-chain complex is the building block of the intermediate filament. The eight-chain complexes are arranged in a half-staggered fashion within the intermediate filament.

Animals↗
PubMed1990

Molecular architecture of the neurofilament. II. Reassembly process of neurofilament L protein in vitro.

Reassembly of the neurofilament (NF) in vitro was studied by low-angle rotary shadowing electron microscopy. Various intermediate stages of the reassembly were reconstructed from the smallest molecular mass subunit (NF-L) under controlled reassembly conditions. NF-L in 6 M-urea took the form of spherical particles with a diameter of about 12 nm. NF-L aggregated into rodlets of 70 to 80 nm long in a low-salt solution at alkaline pH. By reducing the pH of the dialyzing solution to 6.6, a pair of rods was formed by association side-by-side. Increasing the temperature of low-salt solutions from 4 degrees C to 35 degrees C did not produce intermediate-sized filaments. The addition of Mg2+ to the dialyzing solution resulted in the formation of short intermediate-sized filaments even at 4 degrees C. Further dialysis of the short intermediate-sized filaments against reassembly solution containing both NaCl and MgCl2 at 37 degrees C failed to elongate them into longer filaments, suggesting that annealing does not contribute to the elongation of neurofilaments. Different roles for Mg+ and NaCl in neurofilament reassembly were indicated. While Mg2+ strengthened the lateral association between 70 to 80 nm rods, NaCl appeared to promote the end-to-end association of filaments preferentially. Longer filaments were formed by increasing the NaCl concentration. By dialyzing NF-L against a buffer containing 50 mM-NaCl in the absence of Mg2+, unraveled filaments were formed. The many unraveled filaments were composed of four 8 nm wide filaments, which have been called the subfilament or the protofibril. Time-course experiments of the reassembly were performed in the absence of Mg2+, in which condition the rate of neurofilament reassembly appeared to be reduced. Star-like clusters, about four protofibrils joined together at one end, were suggested to be the initial stage of the intermediate-sized filament formation. The following two-step elongation mechanism of neurofilaments was deduced from these results. The pairs of rods were added to the ends of the protofibrils of neurofilaments, and after all four protofibrils were elongated they were then packed into neurofilaments. Distribution of larger molecular mass subunits, NF-M and NF-H, was studied. Addition of NF-M or NF-H to NF-L did not change the assembly properties of neurofilaments. Unraveled filaments reconstituted from NF-L plus either NF-M or NF-H indicated that NF-M and NF-H are incorporated evenly into each protofibril.

Animals↗
PubMed1990

Isolation, characterization, and immunochemical properties of a giant protein from sea urchin egg cytomatrix.

A giant protein of apparent molecular weight (Mr) 2000 kDa, as determined by SDS-PAGE, was isolated and partially purified, under denaturing conditions, from the detergent-resistant cytomatrix of unfertilized sea urchin egg. Immunoblot analysis and indirect immunofluorescence microscopy observations indicated that this high-molecular-weight protein cross-reacted with the immunospecific serum raised against chicken breast muscle beta-connectin. However, rotary-shadowing electron microscopy images of the protein revealed short threadlike structures which appear morphologically different from beta-connectin structure. Indirect immunofluorescence localization of the protein with anti-beta-connectin serum showed a distribution throughout the whole unfertilized egg cytomatrix. This immunofluorescence pattern seems to change upon egg fertilization, since at metaphase the fluorescence stain appears to be excluded from the mitotic apparatus region as revealed by the double immunolabeling with anti-beta-connectin serum and monoclonal anti-alpha-tubulin antibody. Moreover, when egg cortical fragments were double-labeled with anti-beta-connectin serum and rhodamin-conjugated phalloidin, it was observed that the microfilaments assembled after fertilization seem to be in close association with the protein at the cleavage furrow and other locations. The possible significance of this sea urchin egg connectin(titin)-like protein is discussed.

Animals↗
PubMed1990

Effects of phosphorylation of the neurofilament L protein on filamentous structures.

Effects of phosphorylation of the neurofilament L protein (NF-L) on the reassembly system were studied by both sedimentation experiments and low-angle rotary shadowing. Bovine spinal cord NF-L was phosphorylated with 3-4 mol/mol protein by either the catalytic subunit of cAMP-dependent protein kinase or protein kinase C. Phosphorylated NF-L could not assemble into filaments. Phosphorylation by either cAMP-dependent protein kinase or protein kinase C inhibited the same step of the reassembly process. Phosphorylated NF-L remained as an 8-chain complex even in favorable conditions for reassembly. The extent of the effect of phosphorylation on the filamentous structure of NF-L was also investigated by using the catalytic subunit of cAMP-dependent protein kinase. The amount of unassembled NF-L increased linearly with increased phosphorylation in the sedimentation experiments. Structural observations indicated that 1 or 2 mol of phosphorylation is enough to inhibit reassembly and to induce disassembly, and the disassembly process was also observed. The filaments were shown to unravel with disassembly. Star-like clusters, which we reported as being the initial stage of reassembly, were also identified.

Animals↗
PubMed1990

Holter electrocardiogram monitoring in nephrotic patients during methylprednisolone pulse therapy.

We assessed the effect of intravenous methylprednisolone pulse therapy (IMPT) on cardiac rhythm and electrolyte metabolism in patients with nephrotic syndrome. A total of 25 patients had valid evaluations with continuous ambulatory electrocardiograms, and 20 of these had simultaneous sodium and potassium clearances. No significant difference of frequency in complex ventricular arrhythmias (Lown's grades 3-5) between the control and the therapy period was observed; however, 4 patients showed complex ventricular arrhythmias including ventricular tachycardia (2 patients) during the course of therapy. Fractional excretion of potassium and serum potassium significantly increased from baseline after IMPT. Complex ventricular arrhythmias, sometimes leading to sudden death, might ensue from IMPT. These dysrhythmias may be related to an abrupt change in potassium reflux from the cell.

Adult↗