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B Wellek

Publications and source records attributed to B Wellek.

11 recordsLinked to original sources
PubMed2000

Syndrome of autosomal recessive polycystic kidneys with skeletal and facial anomalies is not linked to the ARPKD gene locus on chromosome 6p.

We report on two sibs, both males, one born at 37 the other at 24 weeks of gestation, both with a syndrome similar to that seen in three sets of sibs by Gillessen-Kaesbach et al. [1993: Am J Med Genet 45:511-518]. Both propositi had polycystic kidneys and hepatic fibrosis indistinguishable from that seen in autosomal recessive polycystic kidney disease (ARPKD), and skeletal and facial anomalies. Skeletal abnormalities included "butterfly" vertebrae, square shape of pelvis, and brachymelia. The facial anomalies included hypertelorism, epicanthic folds, and anteverted nares. Additional external findings were apparently low-set ears and a short neck. Histopathological examination of the kidneys showed radial orientation and cystic dilatation of the cortical and medullar tubules. The liver showed "congenital hepatic fibrosis." The hepatic findings in the second infant were less severe. Renal abnormalities were limited to focal tubular cystic changes. Linkage analysis with polymorphic markers of the region 6p21.1-p12, flanking the gene locus of ARPKD, showed different haplotypes in the sibs, thus excluding the ARPKD gene locus in this family and indicating genetic heterogeneity.

Abortion, Induced↗
PubMed1978

Antibody-independent interaction of the first component of complement with Gram-negative bacteria.

The interaction of the first component of complement with two serum-sensitive strains of Escherichia coli and Klebsiella pneumoniae was studied. It could be demonstrated that highly purified C1, free of immunoglobulin G and immunoglobulin M, binds to E. coli or K. pneumoniae. C1 binding was also found with specifically absorbed human serum, after incubation of bacteria with normal serum in the presence of ethylenediaminetetraacetate or agammaglobulinemic serum; the number of C1 molecules taken up by the bacteria was not influenced, indicating that C1 binding was independent of naturally occurring antibodies. C1 bound to bacteria was still able to cleave C4, the natural substrate of C1. From these observations, it is concluded that C1 in an enzymatically active state can be bound directly to bacteria independently of antibody.

Complement C1↗
PubMed1977

Interactions between mycoplasma pneumoniae and the first components of complement.

Mycoplasma pneumoniae cells were rounded and killed by fresh guinea pig serum (GPS) which did not contain detectable amounts of antibody. The first component of complement (C1) was bound by M. pneumoniae in considerable amounts from both GPS and purified C1. The C1 bound by the cells was reacting with C4. Sequential addition of C1, C4, C2, and C-ethylenediaminetetraacetate to glass-grown M. pneumoniae cells resulted in rounding of a significant number of cells. M. orale and M. fermentans showed a reduced binding capacity for C1 as compared with M. pneumoniae. Both species were only slowly killed by fresh GPS, whereas M. hominis was as sensitive as M. pneumoniae. The results suggest an antibody-independent interaction between some components of the membrane surface of M. pneumoniae and C1, resulting in an activation of the complement system leading to the killing of the mycoplasma cells.

Animals↗
PubMed1976

Lack of linkage between gene(s) controlling the synthesis of the seventh component of complement and the HLA region on chromosome No. 6 in man.

The family of an individual was studied who lacks the seventh component of complement in his serum (C7 homozygous deficiency). Both parents are C7 heterozygous-deficient. In this investigation, the following parameters were determined: complement components in functional and immunochemical tests; HLA-A,B antigens, HLA-D (MLC) determinants; the Bf system; glyoxalase I and B cell antigens. No evidence for linkage between the immunogenetic linkage group on chromosome 6 and gene(s) controlling the synthesis of the seventh component of complement was obtained. This is in according with the assumption that only genes controlling components of the initiating rather than the membrane attack unit of complement are linked to the HLA region.

Child↗
PubMed1976

Quantitative contributions of IgG, IgM and C3 to erythrophagocytosis and rosette formation by peritoneal macrophages, and anti-opsonin activity of dextran sulfate 500.

In vitro phagocytosis by guinea pig peritoneal macrophages of immune complexes (EA) was shown to be dependent on IgG antibody in a dose-dependent fashion. C3b enhanced phagocytosis of EA at limited IgG antibody concentrations only. When IgM antibody was used for sensitization of sheep red blood cells (SRBC), phagocytosis and rosette formation did not occur in the absence of bound C3. The polyanion, dextran sulfate 500 (DS), was shown to depress both rosette formation and phagocytosis of EAIgG, C1423 and EAIgMC1423, as well as immune adherence of human group 0 erythrocytes and hemolytic activity of C3. This effect of DS was seen only when it was actually present in the incubation medium.

Animals↗
PubMed1976

Opsonizing activities of IgG, IgM antibodies and the C3b inactivator-cleaved third component of complement in macrophage phagocytosis.

Phagocytosis of SRBC by guinea-pig peritoneal macrophages is enhanced by opsonizing IgG antibody alone. IgM antibody requires the presence of bound C3. Treatment of C3b coated SRBC with purified C3b inactivator (yielding EAIgM C1423d) does not reduce attachment to, and phagocytosis by, peritoneal macrophages. This finding suggests the existence of a C3d receptor on peritoneal macrophages. EC43b intermediates which have been produced by removing IgM antibody by mercaptoethanol treatment and by subsequent removal of C1 and C2, are phagocytosed despite the absence of IgM antibody. Furthermore, treatment of EC43b with C3b inactivator does not change phagocytosis. Thus, IgM antibody does not appear to be a necessary prerequisite for the stimulation of phagocytosis, C3b or C3d alone being sufficient.

Animals↗
PubMed1975

Evidence for macrophage C3d-receptor active in phagocytosis.

Evidence is presented that guinea pig peritoneal macrophages possess membrane receptors able to recognize the C3b inactivator-cleaved third component of complement. This conclusion is based on the finding that rosette formation and phagocytosis by macrophages of EA-IgM-C1423 were equal regardless of whether EA-IgM-C1423 had been pretreated with C3b inactivator or not.

Animals↗
PubMed1975

A case of deficiency of the seventh component of complement in man. Biological properties of a C7-deficient serum and description of a C7-inactivating principle.

The serum of a 13-year-old healthy boy was found to be deficient in whole complement activity. The seventh component of complement could not be detected by functional assays whereas the titres of the other components were found within the normal range. An attempt to detect C7 by immunodiffusion against an antiserum to human C7 also failed. The functions of C1-C6 were normal with respect to opsonizing activity, immune adherence, and the ability to generate chemotactic activity. However, those functions that require the whole complement sequence such as bactericidal and haemolytic activity were found to be absent. Furthermore, the occurrence of a C7-inactivating principle was demonstrated in the C7-deficient serum. This principle inactivated C7 both in the fluid phase and in its cell-bound state. Some physicochemical parameters of the inactivator are described and its possible nature is discussed.

Adolescent↗