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Biomedical subjects

Y Sugisaki

Publications and source records attributed to Y Sugisaki.

At least 55 records · Page 3Linked to original sources
PubMed1992

Calcification in human osteoblasts cultured in medium conditioned by the prostatic cancer cell line PC-3 and prostatic acid phosphatase.

A medium that had been conditioned by PC-3 cells stimulated the calcification of a human osteoblastic cell line, Tak-10, in a nonmitogenic culture. The calcification of the osteoblasts was stimulated maximally at a 25% concentration of the conditioned medium. Calcification activity was markedly enhanced by the addition of both prostatic acid phosphatase (PAP) and its substrate, alpha-glycerophosphate, to the medium; however, PAP added alone did not enhance this activity. These results suggest that human prostatic carcinoma cells produce a factor that stimulates the calcification of the human osteoblasts. Results have also suggested that PAP is a requisite for osteogenesis provided that its substrates are abundant in the medium.

Acid Phosphatase↗
PubMed1991

Role of conserved proline residues in stabilizing tryptophan synthase alpha subunit: analysis by mutants with alanine or glycine.

To study the role of Pro residues in the conformation and conformational stability of a protein, nine mutant alpha subunits of tryptophan synthase from Escherichia coli, in which Ala or Gly was substituted for each of six Pro residues (positions 28, 57, 62, 96, 132, and 207) that are conserved in 10 microorganisms, were constructed by means of site-directed mutagenesis. The far-ultraviolet (UV) CD spectra of five mutant alpha subunits with Ala in place of Pro were identical to the spectrum of the wild-type protein, the exception being the mutant at position 207 (P207A). CD values in the far-UV region were less negative for P207A, indicating that the Pro residue at position 207 plays a role in maintaining the intact structure of the alpha subunit. The negative CD values of the Gly mutants examined (P28G, P96G, and P132G) were also decreased. Calorimetric measurements showed that the two mutants at position 28 (P28G and P28A) gave two peaks in the excess heat capacity curve, whereas the wild type and other Pro mutants had only a single peak. The stability of each mutant protein relative to that of the wild type was about the same for P57A, less for P62A and P132A, and markedly decreased for P96A and P207A, which are substituted at less mobile positions. The changes of denaturation entropy (delta delta dS) at the denaturation temperature of the wild-type protein (54.1 degrees C at pH 9.0) were positive for P57A, P62A, and P132A, but negative for P96A, P207A, and P132G.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine↗
PubMed1991

Effect of dextrans of various molecular weights on mesangial transport in ddY mice pretreated with sheep anti-type IV collagen serum.

The authors' previous report concluded that increased mesangial IgA deposition seen in ddY mice pretreated with mesangiotropic anti-type IV collagen serum might be due to a dysfunction of mesangial transport of macromolecules such as polymeric autologous IgA. In the present study we examined the effect of macromolecules upon mesangial transport in similarly treated ddY mice, using intravenously administered FITC-labeled dextrans of various molecular weights as tracers. The intensity of each resulting mesangial dextran deposit inspected directly by immunofluorescence was measured periodically and compared with the deposition of autologous mouse IgA examined using rhodamine-labeled rabbit anti-mouse IgA. High-molecular-weight dextran of 2,000 kDa showed prolonged mesangial deposition which paralleled the intensity and distribution of the autologous mouse IgA deposition. In contrast, medium- and low-molecular-weight dextrans of 500 and 150 kDa, respectively, disappeared earlier from the mesangium, unlike the autologous IgA deposition which persisted. Based on these results, it was concluded that the macromolecularity of certain substances and a transport dysfunction of the mesangium may both be major factors in prolonged mesangial deposition. These findings may provide some clues to help clarify the pathogenesis of human IgA nephritis.

Animals↗
PubMed1990

The role of cationic proteins in the pathogenesis of immune complex glomerulonephritis.

In spite of intensive endeavours, attempts to identify nephritogenic antigens in cases of immune complex glomerulonephritis have not yielded convincing results. Cationic antigens can have high affinity for the glomerular basement membrane and are prime candidates as nephritogens. They can be expected to play a role in post-infectious and in autoimmune glomerular disease. Histones show great promise in the latter case: we are able to demonstrate (1) a high affinity for the glomerular basement membrane and (2) their ability to promote glomerular deposition of anionic antigens as an additional target. Histones were detectable in glomerular deposits in two murine models of glomerulonephritis: the spontaneous lupus-like disease of NZB/W F1 mice and in graft-versus-host disease. We propose that histones may be responsible for the induction of glomerulonephritis in lupus-like syndromes, as well as other types of autoimmune renal disease. As an analogue, histone-like proteins from micro-organisms may also be responsible for glomerular disease in post-infectious nephritis.

Animals↗
PubMed1989

Histones have high affinity for the glomerular basement membrane. Relevance for immune complex formation in lupus nephritis.

An effort has been made to integrate insights on charge-based interactions in immune complex glomerulonephritis with nuclear antigen involvement in lupus nephritis. Attention was focussed on the histones, a group of highly cationic nuclear constituents, which could be expected to bind to fixed anionic sites present in the glomerular basement membrane (GBM). We demonstrated that all histone subfractions, prepared according to Johns (4), have a high affinity for GBM and the basement membrane of peritubular capillaries. Tissue uptake of 125I-labeled histones was measured by injecting 200 micrograms of each fraction into the left kidney via the aorta and measuring organ uptake after 15 min. In glomeruli isolated from the left kidneys, the following quantities of histones were found: f1, 13 micrograms; f2a (f2al + f2a2), 17 micrograms; f2b, 17 micrograms; and f3, 32 micrograms. Kinetic studies of glomerular binding showed that f1 disappeared much more rapidly than f2a. The high affinity of histones (pI between 10.5 and 11.0; mol wt 10,000-22,000) for the GBM correlates well with their ability to form aggregates (mol wt greater than 100,000) for comparison lysozyme (pI 11, mol wt 14,000), which does not aggregate spontaneously bound poorly (0.4 micrograms in isolated glomeruli). The quantity of histones and lysozyme found in the isolated glomeruli paralleled their in vitro affinity for a Heparin-Sepharose column (gradient elution studies). This gel matrix contains the sulfated, highly anionic polysaccharide heparin, which is similar to the negatively charged heparan sulfate present in the GBM. Lysozyme eluted with 0.15 M NaCl, f1 with 1 M NaCl, and f2a, f2b, and f3 could not be fully desorbed even with 2 M NaCl; 6 M guanidine-HCl was necessary. Two further findings of great relevance for the concept of induction of immune complex glomerulonephritis by histones were: (a) glomerular-bound histone was accessible for specific antibody given intravenously; and (b) prior binding of histones promoted glomerular deposition of anionic antigens, as could be shown with ssDNA fragments. These data justify the proposal that glomerular deposition of histones can induce immune complex formation, start an inflammatory process, and produce tissue damage.

Animals↗
PubMed1989

Evidence of delayed mesangial transport of human IgA in glomeruli of ddY mice pretreated with sheep anti-type IV collagen serum.

In order to investigate whether mesangial transport by glomeruli is delayed in ddY mice pretreated with sheep anti-type IV collagen serum, the mice were administered an overload of human IgA myeloma serum. Non-pretreated ddY mice used as controls and both experimental and control BALB/c mice were also processed in a similar manner. The intensities of mesangial deposition of human IgA were examined periodically and were found to correlate well with deposition of mouse IgA. Both mouse and human IgAs showed a gradual increase for up to 8 experimental weeks. In the control young ddY mice, however, the overloaded mesangial human IgA quickly disappeared, presenting no appreciable mesangial deposition of autologous IgA. In sharp contrast, both the experimental and control BALB/c mice showed an initially prolonged and rather heavy mesangial deposition of human IgA, followed by a gradual decrease and somewhat light mesangial deposition of autologous mouse IgA. These results obtained using experimental ddY mice appear to confirm the possibility that non-immunological local trapping, due to retardation of mesangial transport function, causes mesangial deposition of autologous mouse IgA in this particular strain.

Animals↗
PubMed1989

[Macromolecular basis of filtration and immune complex pathogenesis in the glomerulus].

Fractional clearance and ultrastructural studies produce results consistent with the idea that the glomerular filtration barrier is a heteroporous membrane. The majority of the pores being small, excluding molecules like serum albumin and larger moieties, while a low number of pores allow the passage of molecules as big as dimeric ferritin, in very restricted quantities. Cationic macromolecules, of a size which should effectively exclude them from the filtration process, readily gain access to all three layers of the GBM. Depending on charge (pI) and size they can in fact exhibit significant affinity for negatively charged structures in both laminae rarae. In addition, polycations can mediate the glomerular deposition of anionic macromolecules, for example DNA-fragments, by diminishing charge repulsion. A prerequisite for the local formation of glomerular immune complexes is that at least one of the reaction partners has an affinity for the GBM. Antigens bound to structures in the laminae rarae are accessible for circulating antibody. Immune complexes formed with cationic antigen in the lamina rara interna are transferred to the subepithelial region with time. Antigen and antibody molecules can penetrate the lamina densa only in dissociated form. The persistence of glomerular immune complexes can be explained by antigen-antibody lattice formation within the network of proteoglycan chains, followed by covalent binding between components of the complex and structures of the GBM.

Animals↗
PubMed1986

Immunohistochemical localization of glomerular basement membrane antigens in various renal diseases.

The immunofluorescent localization of glomerular basement membrane (GBM) antigens was examined in 52 specimens from normal kidneys and in various renal diseases using antisera to human GBM (HGBM), IV type collagen (IV Col) and P3 antigen, a rat nephritogen. Anti-HGBM serum normally stained the GBM and the mesangium in a restrictive pattern, anti-IV Col serum stained the GBM and the mesangium in a wider pattern and anti-P3 serum stained only the GBM. In mesangial proliferative glomerulonephritis, including IgA nephropathy and Henoch-Schönlein nephritis, the widened mesangial areas were stained with anti-HGBM and anti-IV Col sera. In membranous nephropathy, the punched-out lesions of thickened GBM were demonstrated with the three antisera in moderate cases and a double linear distribution with fine granulation with anti-HGBM and anti-IV Col sera were revealed in one severe case. In membranoproliferative glomerulonephritis, the expanded mesangium and thickened capillary walls were stained with anti-HGBM and anti-IV Col sera, while the outer line of glomerular capillary walls was only positive with anti-P3 serum. In crescentic glomerulonephritis, the collapsed glomerular tufts were stained normally with anti-HGBM and anti-P3 sera and weakly with anti-IV Col serum. In diabetic nephropathy, anti-HGBM serum stained the GBM in a double linear distribution without reacting with the expanded mesangium; anti-IV Col serum stained the mesangium and the GBM in a less clear double linear fashion while anti-P3 serum stained the GBM as single line. Thin membrane disease and Alport's syndrome had normal reactivity with all antisera. However, in one case of Alport's syndrome anti-HGBM and anti-P3 sera stained the GBM in a focal and segmental pattern, while normal staining with anti-IV Col serum was found. In lesions with adhesions and crescents the staining was positive for HGBM and IV Col and negative for P3; obsolescent glomeruli were stained with anti-HGBM and anti-P3 sera, and had diminished staining with anti-IV Col serum. The identification of the various structural glomerular antigens is useful in the classification of certain types of glomerular diseases. Further insight into the mechanisms underlying these conditions may be obtained in this way.

Antigens↗
PubMed1986

Experimental mesangioproliferative glomerulonephritis in rats induced by intravenous administration of anti-thymocyte serum.

Focal glomerulonephritis was induced in rats, by a single intravenous injection of anti-Thy-1.1 antibody (ATS). One hour after the administration, the glomeruli of affected rats developed necrotic changes of the mesangial cells while after two hours, mesangiolytic changes appeared. From six days onwards, focal segmental mesangial proliferation which persisted until 30 days, occurred. This is thought to be the first report of experimental nephritis induced by pure anti-mesangial antibody.

Animals↗
PubMed1985

Seroepidemiology of human T-lymphotropic retrovirus type I (HTLV-I) in residents of Niigata Prefecture, Japan. Comparative studies by indirect immunofluorescence microscopy and enzyme-linked immunosorbent assay.

A large sample of carriers of human T-lymphotropic retrovirus type I (HTLV-I) in Niigata Prefecture was examined for the detection of natural antibodies to HTLV-I-related antigens in sera using both indirect immunofluorescence microscopy (IFM) and enzyme-linked immunosorbent assay (ELISA). The present findings are based on multiple surveys, using each assay technique at least twice. Although Niigata Prefecture has been considered a non-endemic region for HTLV-I, Sado Island has been proven by this study to be a relatively endemic pocket within this non-endemic area. Seropositivity was highest in residents of Sado Island; 97/1, 117 (8.7%) by IFM and 33/1,061 (3.1%) by ELISA; followed by Niigata City, 18/650 (2.8%) by IFM and 16/638 (2.5%) by ELISA; and lowest in the remaining areas, 57/2,631 (2.2%) by IFM and 20/2,551 (0.8%) by ELISA. Seropositivity was demonstrated in 172/4,398 (3.9%) by IFM and 69/4,250 (1.6%) by ELISA in Niigata Prefecture taken as a whole. In general, the incidence of seropositive residents increased gradually with age. The sex difference was not significant. The serum samples tested were categorized into 4 groups; (1) IFM and ELISA both positive, (2) IFM positive but ELISA negative, (3) IFM negative but ELISA positive, and (4) IFM and ELISA both negative. By absorption tests, IFM and ELISA seemed to recognize different specific antibodies in sera; IFM recognized antibodies to HTLV-I-related cellular antigens in addition to HTLV-I viral antigens, but ELISA recognized antibodies to HTLV-I viral antigens alone. Thus, IFM detected a broader spectrum of antigens, resulting in recognition of more positive sera than those detected by ELISA.

Adolescent↗
PubMed1985

Transfer of DNA killer plasmids from Kluyveromyces lactis to Kluyveromyces fragilis and Candida pseudotropicalis.

Killer plasmids pGKL1 and pGKL2 of double-stranded linear DNAs were transferred from Kluyveromyces lactis to strains of Kluyveromyces fragilis and Candida pseudotropicalis. The resultant killer strains produced 17-fold and 6-fold larger amounts of killer toxin than K. lactis did, respectively. The killer toxin produced by each species appeared to be a glycoprotein.

Bacterial Toxins↗
PubMed1985

[Healing of operative cardiac wounds].

Healing process of operative cardiac wounds was studied histopathologically in 14 patients who died 28 hours to 5 years after the operation of cardiac valve replacement. Repair of wounds in aorta and free wall of atrium was characterized by production of neointima and proliferation of collagen fiber at adventitia of aorta or epicardium of heart. Adhesion with granulation tissue at left ventricular venting wounds was observed in the case of 18th post-operative day. Reticulofibrosis of surrounding intracardiac muscle played an important role in development of granulation tissue. Cicatrix with collagen fiber was appeared from one month after the operation. In spite of attenuation of ventricular scar, aneurysmal bulging could not be observed. The basic healing pattern of wound in atrial septum was production and thickening of neointima. Granulation tissue rarely developed at the septum. Adhesion between sutured edges of atrial septal endocardium could not be observed and the dead space there remained over a period of 7 months after the operation. These findings indicated the continuous presence of unexpected weakness of the sutured septum until sufficient thickening of neointima had developed.

Adult↗
PubMed1984

Characterization of a novel killer toxin encoded by a double-stranded linear DNA plasmid of Kluyveromyces lactis.

A novel killer toxin, encoded by a double-stranded linear DNA plasmid pGK l-1 (5.4 MDa) in Kluyveromyces lactis IFO 1267 was purified 320 000-fold from the culture broth of yeast. The toxin was obtained in an electrophoretically homogeneous state with a yield of 24% by hydroxyapatite column chromatography, chromatofocusing and polyacrylamide gel electrophoresis. The purified toxin was dissociated into two subunits with molecular masses of 27 kDa and above 80 kDa, as estimated by Laemmli's sodium dodecylsulfate gel electrophoresis; the exact composition ratio of the two subunits remains unestablished. The isoelectric point was between 4.4 and 4.8. As compared with the reported narrow pH range of action and instability of k1 killer toxin encoded by a double-stranded RNA plasmid of Saccharomyces cerevisiae, the K. Lactis toxin was effective with sensitive strains of S. cerevisiae in a relatively wider pH range between 4 and 8; it was stable for several months at pH 6.0 when stored below -20 degrees C. In contrast to the simple protein nature of the k1 killer toxin with a molecular mass of 11.47 kDa, the K. lactis toxin maintained a mannoprotein nature, as it was absorbed by a ConA-Sepharose column and eluted by methyl alpha-D-mannoside. The growth inhibitory activity of K. lactis toxin was enhanced 2-35-fold by the presence of 4-60% glycerol.

Ascomycota↗