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Biomedical subjects

F Gejyo

Publications and source records attributed to F Gejyo.

At least 199 records · Page 11Linked to original sources
PubMed1987

Chemical characterization of urinary glycopeptides.

We prepared human urinary glycopeptides from the supernatant liquid remaining after precipitation of the nondialyzable fraction with cetylpyridinium chloride. Using cation exchange and affinity chromatographies and gel filtration, we obtained 28 glycopeptide subfractions. By compositional analyses of sugar and amino acid, and by reducing-terminal analyses after reduction with NaBH4, we determined the size of the carbohydrate moiety and the types of carbohydrate-peptide linkage involved. We isolated several glycopeptides not previously described: six with sialic acid, two with fucose, two with glucose, and one with N-acetylgalactosamine. The sialic acid glycopeptides had a short carbohydrate chain of the O-glycoside type. The fucose-containing glycopeptides were fucosyllactosaminoglycans. The glucose glycopeptides were polymers linked to a small peptide moiety. The N-acetylgalactosamine-rich glycopeptide was found in an N-glycoside-type fraction, with N-acetylgalactosamine at the nonreducing terminal.

Acetylglucosamine↗
PubMed1986

Inhibitory effects of beta 2-microglobulin on in vitro calcification of osteoblastic cells.

Elevated levels of aluminum and beta 2-microglobulin have been demonstrated in chronic dialysis patients. The role of aluminum in the pathogenesis of renal osteodystrophy has also been shown. We report on the effects of beta 2-microglobulin on calcification in vitro using osteoblastic cells, clone MC3T3-El. At concentrations comparable to those in plasma of chronic dialysis patients, both beta 2-microglobulin and aluminum suppressed calcification while collagen synthesis and alkaline phosphatase activity were maintained. These observations may be related to the impaired bone mineralization frequently observed in chronic dialysis patients.

Alkaline Phosphatase↗
PubMed1986

The complete amino acid sequence of the A-chain of human plasma alpha 2HS-glycoprotein.

Normal human plasma alpha 2HS-glycoprotein has earlier been shown to be comprised of two polypeptide chains. Recently, the amino acid and carbohydrate sequences of the short chain were elucidated (Gejyo, F., Chang, J.-L., Bürgi, W., Schmid, K., Offner, G. D., Troxler, R.F., van Halbeck, H., Dorland, L., Gerwig, G. J., and Vliegenthart, J.F.G. (1983) J. Biol. Chem. 258, 4966-4971). In the present study, the amino acid sequence of the long chain of this protein, designated A-chain, was determined and found to consist of 282 amino acid residues. Twenty-four amino acid doublets were found; the most abundant of these are Pro-Pro and Ala-Ala which each occur five times. Of particular interest is the presence of three Gly-X-Pro and one Gly-Pro-X sequences that are characteristic of the repeating sequences of collagens. Chou-Fasman evaluation of the secondary structure suggested that the A-chain contains 29% alpha-helix, 24% beta-pleated sheet, and 26% reverse turns and, thus, approximately 80% of the polypeptide chain may display ordered structure. Four glycosylation sites were identified. The two N-glycosidic oligosaccharides were found in the center region (residues 138 and 158), whereas the two O-glycosidic heterosaccharides, both linked to threonine (residues 238 and 252), occur within the carboxyl-terminal region. The N-glycans are linked to Asn residues in beta-turns, while the O-glycans are located in short random segments. Comparison of the sequence of the amino- and carboxyl-terminal 30 residues with protein sequences in a data bank demonstrated that the A-chain is not significantly related to any known proteins. However, the proline-rich carboxyl-terminal region of the A-chain displays some sequence similarity to collagens and the collagen-like domains of complement subcomponent C1q.

Amino Acid Sequence↗
PubMed1986

Beta 2-microglobulin: a new form of amyloid protein associated with chronic hemodialysis.

Carpal tunnel syndrome (CTS) has been associated with amyloid deposits and is now regarded as a major complication in chronic hemodialysis patients. While this new syndrome has been receiving increasing attention, its etiology has not been clarified. We have isolated amyloid fibrils from amyloid laden tissues inside the carpal tunnel in four different hemodialysis patients with CTS. After solubilization in guanidine HCl, a significant amount of the protein was located in a homogeneous, low molecular weight fraction. Each protein was found to be identical to beta 2-microglobulin with regard to its molecular weight of 11,000 on SDS-PAGE, amino acid composition and N-terminal amino acids: Ile-Gln-Arg-Thr-Pro-Lys-Ile-Gln-Val-Tyr-Ser-Arg-His-Pro-Ala-Glu. In direct immunofluorescent study, anti-beta 2-microglobulin did react positively with amyloid deposits. These results demonstrate that the amyloid associated with chronic hemodialysis contains as major component a new form of amyloid fibril protein that is homologous to beta 2-microglobulin. It is postulated that beta 2-microglobulin cannot be removed from the blood by conventional hemodialysis, and accumulates in tissues causing the formation of amyloid fibrils, which, having a relatively high affinity to the carpal tunnel area, thus causes CTS.

Amino Acids↗
PubMed1985

A new form of amyloid protein associated with chronic hemodialysis was identified as beta 2-microglobulin.

Amyloid fibrils were isolated from amyloid-laden tissue obtained from a chronic hemodialysis patient with carpal tunnel syndrome. After solubilization in guanidine HCl, a significant amount of the protein was located in a homogeneous low molecular weight fraction. The protein was found to be identical to beta 2-microglobulin, with regard to its molecular weight of 11,000, amino acid composition and 16 amino-terminal amino acids: Ile-Gln-Arg-Thr-Pro-Lys-Ile-Gln-Val-Tyr-Ser-Arg-His-Pro-Ala-Glu-. These results demonstrate that the amyloid associated with chronic hemodialysis contains as major component a new form of amyloid fibril protein that is homologous to beta 2-microglobulin.

Amino Acid Sequence↗
PubMed1985

Physiologic approach to dialysis-induced hypoxemia. Effects of dialyzer material and dialysate composition.

This study was undertaken to evaluate the effects of membrane-related complement activation and dialysate composition on dialysis-associated hypoxemia. Seven chronic hemodialysis patients were hemodialyzed 3 times sequentially with the following three combinations; Cuprophan membrane with acetate dialysate, polymethylmethacrylate (PMMA) membrane with acetate dialysate, and PMMA membrane with bicarbonate dialysate. During dialysis with acetate dialysate, the pulmonary diffusing capacity (DLco) at 30 min after the start of dialysis was decreased to 88% (p less than 0.01) of the predialysis value with PMMA and to 79% (p less than 0.01) with Cuprophan, and the degree of DLco on PMMA membrane was different from that on Cuprophan (p less than 0.01). The degree of leukopenia with PMMA was less than that with Cuprophan. However, the fall in DLco did not alter the alveolar-arterial O2 tension gradient. Although the changes in transcutaneous PO2 (tcPO2) were not constant in all three combinations, a distinct fall in tcPO2 was observed in the first half of dialysis with acetate dialysate. During dialysis with acetate dialysate but not with bicarbonate, the extracorporeal dialyzer removed an average of 60 ml/min of CO2, and the respiratory quotient dropped from a mean predialysis value of 0.86 to 0.59 (p less than 0.001). The arterial CO2 tension was not significantly changed throughout dialysis, but the alveolar ventilation decreased significantly in proportion to the fall in carbon dioxide output. The arterial tension fell from a control level of 91 +/- 6 to 77 +/- 8 mm Hg (p less than 0.01) in 30 min. It is concluded that, in spite of a fall in DLco, dialysis-induced hypoxemia in this group of patients on maintenance dialysis is caused by CO2 loss via the dialyzer, resulting in reflex hypoventilation.

Acetates↗
PubMed1985

Histochemical and immunohistochemical characterization of amyloid associated with chronic hemodialysis as beta 2-microglobulin.

The carpal tunnel syndrome has been associated with amyloid deposits and is now regarded as a major complication in patients undergoing chronic hemodialysis. The hemodialysis-associated amyloidosis appears to have systemic rather than local involvement, although its full extent is yet to be determined. In an attempt to examine the chemical and immunologic nature of the amyloid, the authors carried out a series of histochemical and immunohistochemical studies with the following results. The amyloid was "sensitive" to the "permanganate treatment," suggesting it was the AA (secondary) type. On immunohistochemistry, however, anti-human AA did not give positive reaction with the amyloid deposits, suggesting that this would be a new form of amyloid. As reported elsewhere, the authors' preliminary results on the amino acid sequence analysis in one specimen have revealed homology of its amino terminal sequence to beta 2-microglobulin. In the present study, anti-beta 2-microglobulin did indeed react positively (with appropriate controls) with the amyloid deposits in the tissues collected from five different patients, confirming the beta 2-microglobulin-related nature of the amyloid. The present observations are significant in two points: (a) they confirm that hemodialysis-associated amyloid is of beta 2-microglobulin origin since it shares same antigenic determinant(s) with it and since the amino acid sequence is homologous; and (b) it adds what many have suspected, i.e., "permanganate-sensitive" amyloid is not specific for the AA type but includes AA and beta 2-microglobulin amyloid deposits at the minimum.

Amyloid↗
PubMed1984

High-performance liquid chromatographic determination of serum aliphatic amines in chronic renal failure.

A high-performance liquid chromatographic method has been introduced for the determination of aliphatic amines in serum as their 2,4-dinitrophenyl derivatives. The method has been applied to the estimation of ethanolamine, methylamine and dimethylamine in serum from patients with chronic renal failure undergoing maintenance haemodialysis. Significant differences in the levels of both methylamine and dimethylamine were obtained between normal subjects and uraemic patients both predialysis and postdialysis. After a dialysis treatment, the levels of these two amines were reduced to approximately 55% in the patient group. Their mean values, however, were found to be about six times the values of the normal group. The degree of removal of these substances during haemodialysis was smaller than those for urea nitrogen and creatinine. On the other hand, the mean ethanolamine level before dialysis was close to that of controls, and yet a 2.3-fold increase was observed after dialysis.

Adult↗
PubMed1983

Characterization of the B-chain of human plasma alpha 2HS-glycoprotein. The complete amino acid sequence and primary structure of its heteroglycan.

alpha 2HS-Glycoprotein, a normal human plasma protein, was recently shown to consist of two polypeptide chains. In the present study, we have separated these two chains from one another and have elucidated the complete primary structure of the B-chain. Employing automated Edman degradation, the polypeptide moiety of this chain was shown to consist of 27 amino acid residues with an unequal distribution of the neutral and charged amino acid residues. The first 20 residues are uncharged, whereas the carboxyl-terminal heptapeptide contains all charged residues. Utilizing 500-MHz 1H-NMR spectroscopy, the carbohydrate unit proved to be a trisaccharide consisting of sialic acid, galactose, and N-acetylgalactosamine O-glycosidically linked to serine (residue 6). The structure of the B-chain was found to be as follows. (formula; see text) Thus, the molecular weight of the B-chain is 3386. Evaluation of the polypeptide chain by the procedure of Chou and Fasman (Chou, P.Y., and Fasman, G.D. (1979) Adv. Enzymol. 47, 45-148) predicts that the B-chain has two beta-turns. Thereby, the carbohydrate unit which is linked to the Ser residue located in the first beta-turn appears to be directed away from the protein. The second beta-turn probably includes the Cys residue which links the B- to the A-chain. In agreement with the CD analysis, the B-chain lacks beta-conformation but possesses a short alpha-helical region.

Amino Acid Sequence↗
PubMed1983

Alpha 2HS-glycoprotein in the serum and urine of patients with renal diseases.

The concentration of alpha 2HS-glycoprotein (alpha 2HS-GP), as measured by the single radial immunodiffusion technique in the sera of 52 patients with various renal diseases and varying degrees of proteinuria, was found to be significantly reduced (P less than 0.001) when compared to the control values. Out of the 52 patients examined, 34 were found to excrete alpha 2HS-GP in urine with no correlation between the serum and urine levels of this protein. Although there is a statistically significant correlation between the clearances of albumin and alpha 2HS-GP, in only six patients were the clearances of alpha 2HS-GP within +/- 25% of albumin clearance. Twelve had higher, and 16 had lower, relative clearances of alpha 2HS-GP. The relative clearance of alpha 2HS-GP had no relation to the serum levels of alpha 2HS-GP, but correlated with the degree of proteinuria and the type of histological lesion in the kidney. In conclusion, there is a quantitative reduction of serum alpha 2HS-GP in patients with renal diseases. It appears that the degree of proteinuria and the type of renal lesion influences its selective handling by the kidneys.

Blood Proteins↗