ISSN:0042-9007    

DOI:10.1111/j.1423-0410.1984.tb01555.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract.The thermal stability of 5% previously unheated, undefatted human albumin monomer in 145 mMNa+, pH7.0 was investigated by differential scanning calorimetry (DSC) as a function of added caprylate and/or N‐acetyl‐DL‐tryptophanate. Caprylate was substantially more effective than N‐acetyl‐DL‐tryptophanate in protecting the protein against thermal denaturation at a given level or at a saturating level of stabilizer. The tracing of the differential heat capacity versus temperature (thermogram) for this undefatted monomer that contained 1.5 mol endogenous, long‐chain fatty acid (LCFA)/mol monomer exhibits two denaturation peaks (endotherms) in the absence of stabilizer. The endotherm with the lower denaturation temperature (Td) comprises 70% of the total heat of denaturation and also corresponds to irreversible denaturation and precipitation of 70% of the albumin. This endotherm is associated with more thermally labile protein species containing low levels of LCFA. The endotherm with the higher Tdis associated with more stable protein species containing high levels of LCFA. Thus, the two endotherms are not related to the proposed domain structure of the protein but result from an uneven LCFA distribution that is due to preexisting heterogeneity in the albumin and/or heterogeneity that arises during the DSC experiment. Binding data do not support a preexisting uneven distribution of sufficient magnitude to explain the experimental results. A complementary explanation is that an uneven fatty acid distribution arises during the DSC experiment by migration of LCFA from the more labile species to the more stable as the former unfold; such migration would cause further stabilization

ISSN:0042-9007    

DOI:10.1111/j.1423-0410.1984.tb01556.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract.Thermal stability of undefatted human albumin preparations at 5% concentration and neutral pH in 14 5 mMNa+ was investigated by differential scanning calorimetry. At 30 and 4 mMN‐acetyltryptophanate, the thermogram for previously unheated albumin monomer is independent of the stereochemistry of this ligand; thus, the affinity of the protein must be the same for theL‐andD‐isomers in the temperature range of thermal denaturation (62–86 °C). 26 mML‐tryptophanate bestows a slight increase in stability on previously unheated monomer, whereas 27 mM D‐tryptophanate has no effect, a result consistent with the reported weaker binding of theD‐isomer. Previously unheated albumin monomer shows slightly greater thermal stability at pH 6.4 than at pH 7.4. The tracing of differential heat capacity versus temperature (thermogram) for monomer from once heated albumin, i.e. once processed and once heated normal serum albumin (NSA), is almost identical to that for previously unheated monomer. Monomer prepared from outdated, multiply reprocessed, multiply reheated NSA (old monomer) has the same corresponding denaturation temperatures as previously unheated monomer; the corresponding dimer(old dimer) is slightly less stable. Thermograms for old monomer and old dimer, like those for previously unheated monomer, comprise two denaturation peaks (endotherms). Their endotherms, however, are very broad, reflecting the great heterogeneity of the old proteins. The thermogram for old monomer remains broad even in the presence of N‐acetyltryptophanate and/or caprylate. Old dimer does not dissociate when undergoing ther

ISSN:0042-9007    

DOI:10.1111/j.1423-0410.1984.tb01557.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract.The thermal stabilization of human albumin by caprylate (CA) and acetyltryptophanate (AT) was studied by monitoring the formation of albumin polymer (defined as species larger than dimer) on the basis of its molecular size as well as its characteristic migration as α‐globulin. Heating 5% protein solutions of purified albumin monomer, Cohn fraction V, and fraction IV‐4 + V at 60 °C in 0.1Msodium phosphate or 145 mM sodium chloride, pH 7.0, established the following order of stabilizer effectiveness: 4 mMCA + 4 mMAT ≅ 4mMCA>8 mM AT ≥ 2 mMCA>4 mMAT. However, albumin was more thermally stable in the chloride medium. Raising the CA concentration above 4mMprovided little additional stabilization. TheD‐andL‐enantiomers of AT were equally effective, but 16 mMAT was needed to equal the effect of 4 mMCA.L‐Tryptophanate exerted only slight stabilization, even at 32 mM;D‐tryptophanate was even less effective. The albumin polymer level increased progressively with time at 60 °C in 2 mMCA or 4 mMAT, whereas in 4 mMCA it reached a plateau in 4–6 h. Acetone drying of albumin‐rich fractions was shown to remove nearly all endogenous fatty acid, rendering the protein thermally labile unless sufficient exogenous stabilizer(s) was added. Even in the presence of 145 mMsodium chloride and 4 mMCA + 4 mMAT or 4 mMCA, the stabilizing effect of endogenous fatty aci

ISSN:0042-9007    

DOI:10.1111/j.1423-0410.1984.tb01558.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract.Fibronectin was isolated from human blood plasma by affinity chromatography on immobilized Physiogel, a plasma expander made by chemical degradation of gelatin. Binding of fibronectin to Physiogel is weaker than to gelatin; elution could therefore be performed under rather mild conditions: at pH 6.5 and 30°C. Loading of the sample at low temperature increases the capacity of the affinity column

ISSN:0042-9007    

DOI:10.1111/j.1423-0410.1984.tb01559.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract.A population of 30 severe hemophilia‐A patients with antibodies to factor VIII, treated with Autoplex® since 1980, experienced a 30% incidence of non‐A, non‐B (NANB) hepatitis. 8 of the 9 patients affected had clinical signs of hepatitis and 7 had ALT levels in excess of 200 IU/1; the mean incubation time was 13 days. Only 5 of the 26 lots of Autoplex used were possibly transmitting the infective agent. An ELISA test to detect an antigen (DS‐Ag) possibly related to NANB hepatitis was used to screen hemophilia‐A and B patients. Its incidence was lower in patients treated less than 5 times a year (7.9%) than in patients treated over 15 times a year (25–27%) with locally prepared blood derivatives. Following treatment with Autoplex, the incidence of DS‐Ag in inhibitor patients increased significantly (50%). In this last population, DS‐Ag was shown to be unrelated to the NANB hepatitis observed. Although no direct evidence could be given, Autoplex was likely to transmit both the agent responsible for short incubation NANB hep

ISSN:0042-9007    

DOI:10.1111/j.1423-0410.1984.tb01560.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract.1,410 voluntary blood donors from Bangkok were investigated by radioimmunoassay for HBsAg, anti‐HBs, anti‐HBc, HBeAg, anti‐HBe and anti‐HAV. An HBsAg carrier state was observed in 10.7% of whom 42.1% were HBeAg positive and 40.2% had anti‐HBe. Antibody prevalences (except anti‐HBe) rose with increasing age. The occurrence of hepatitis markers did not vary significantly between donors living along the canals and those living in the Greater B

ISSN:0042-9007    

DOI:10.1111/j.1423-0410.1984.tb01561.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract.Monitoring of donors with selective IgA deficiency, i.e., with less than 0.5 mg IgA/1, led to the observation that serum IgA levels were not constant. Small but significant fluctuations in IgA levels were noted (coefficient of variance: 143%) which were greater than the variability inherent in the testing methodology (coefficient of variance: 10%). These fluctuations created difficulties in terms of defining IgA‐deficient blood products and had implications with respect to the mechanisms involved in IgA deficiency. With respect to supplying IgA‐deficient blood products, in our experience a cutoff level of 0.5 mg/1 should be the maximum permissible IgA concentration in order to ensure that no adverse reactions occur in individuals with class‐specific ant

ISSN:0042-9007    

DOI:10.1111/j.1423-0410.1984.tb01562.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract.On return from Liberia, a previously healthy 36‐year‐old man showed signs of malaria accompanied by severe haemolysis and slight thrombocytopenia. We found evidence of a platelet‐associated IgG being responsible for the thrombocytopenia, inasmuch as the direct platelet suspension immunofluorescence test was strongly positive, the indirect immunofluorescence test and tests for drug‐dependent antibodies at the same time being negative. We suggest that autoimmunity may be a contributing mechanism for platelet destruction in acute

ISSN:0042-9007    

DOI:10.1111/j.1423-0410.1984.tb01563.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract.The number of IgG molecules bound to the erythrocyte surface for a given agglutination score in the antiglobulin test was studied with several different examples of anti‐D, anti‐E, anti‐c, anti‐Kell, anti‐Fya, anti‐Jkaand immune anti‐A antisera. The serological scores show a significant correlation with the mean values for bound IgG molecules within a restricted range, although the number bound for a given score may vary by up to 20%. The limit of detection was 100–120 IgG molecules per cell and when over 1,000 were bound, the cells were completely agglutinated. Anti‐Kell bound under low ionic strength saline conditions required a greater number of molecules for a given agglutination strength. The relatively low levels of bound IgG necessary to give strong agglutination make the direct antiglobulin test (DAT) less valuable for following the progress of auto‐immune haemolytic anaemia (AIHA) than a quantitative test. The latter test does not, however, provide any additional information in AIHA cases with a negative DAT as in these the anaemia does not appear to be due simply to the number of bound IgG molecules. Detection of certain antibodies may not be achieved simply by increasing the sensitivity of the antiglobulin test when

ISSN:0042-9007    

DOI:10.1111/j.1423-0410.1984.tb01564.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY