ASGR1 and ASGR2, the Genes that Encode the Asialoglycoprotein Receptor (Ashwell Receptor), Are Expressed in Peripheral Blood Monocytes and Show Interindividual Differences in Transcript Profile.

Background. The asialoglycoprotein receptor (ASGPR) is a hepatic receptor that mediates removal of potentially hazardous glycoconjugates from blood in health and disease. The receptor comprises two proteins, asialoglycoprotein receptor 1 and 2 (ASGR1 and ASGR2), encoded by the genes ASGR1 and ASGR2.

Roles of promoter and 3' untranslated motifs in expression of the human C5a receptor.

The C5a receptor (C5aR) is a 7 transmembrane G-protein coupled receptor (GPCR) that mediates the powerful pro-inflammatory effect of the complement activation product C5a. Excess C5a generated under pathological conditions has been implicated in a variety of conditions including sepsis, asthma and rheumatoid arthritis, but very little is known about the regulation of expression of the C5aR. The 5' promoter region and 3' untranslated region (UTR) of the C5aR mRNA were cloned, generating enhanced green fluorescent protein (EGFP)-reporter plasmids, which were transfected into the monocytic cell line U937.

C1584: effect on von Willebrand factor proteolysis and von Willebrand factor antigen levels.

The present review provides a clearer picture of the effect of C1584 on the level and properties of von Willebrand factor (VWF). The C1584 variant is associated with decreased VWF levels (especially in combination with blood group O) and VWF function, and with slightly enhanced VWF proteolysis, and there is evidence to support its association with enhanced VWF clearance. These properties help explain the enrichment for C1584 in mild type 1 VWD and the observed marked association of the variant and blood group O in this mild bleeding disorder.

A novel deletion mutation is recurrent in von Willebrand disease types 1 and 3.

Direct sequencing of VWF genomic DNA in 21 patients with type 3 von Willebrand disease (VWD) failed to reveal a causative homozygous or compound heterozygous VWF genotype in 5 cases. Subsequent analysis of VWF mRNA led to the discovery of a deletion (c.221-977_532 + 7059del [p.

Survival of von Willebrand factor released following DDAVP in a type 1 von Willebrand disease cohort: influence of glycosylation, proteolysis and gene mutations.

Reduced plasma survival of von Willebrand factor (VWF) may contribute towards the pathogenesis of type 1 von Willebrand disease (VWD). However, little is known about mechanism(s) of VWF clearance and factors that may affect it. The half-life of VWF-related parameters following the administration of DDAVP was measured in 26 patients with type 1 VWD and 10 haemophilia A controls.

The association between the L1565 variant of von Willebrand factor and susceptibility to proteolysis by ADAMTS13.

The cysteine allele of the amino acid polymorphism (AAP) Y/C1584 in the A2 domain of von Willebrand factor (VWF) has been shown to correlate with enhanced VWF proteolysis by ADAMTS13. The frequencies and effect on VWF proteolysis of six reported AAP in VWF domains A1 and A2 were investigated. Only two AAP were variant: 4414 G/C (D/H1472) (allele frequency 0.

Effect of von Willebrand factor Y/C1584 on in vivo protein level and function and interaction with ABO blood group.

Blood group O and the cysteine allele of the Y/C1584 change in von Willebrand factor (VWF) are enriched in type 1 VWD, but neither causes disease. We investigated the effect of C1584, alone and in combination with the ABO blood group, on the level and properties of plasma VWF. A cohort of 5052 blood donors was recruited: 50 donors were heterozygous for Y/C1584 and 5002 were homozygous for Y/Y1584.

An investigation of the von Willebrand factor genotype in UK patients diagnosed to have type 1 von Willebrand disease.

Forty families diagnosed by UK centres to have type 1 VWD were recruited. Following review, six families were re-diagnosed to have type 2 VWD, one to have a platelet storage pool disorder, and one family was determined to be unaffected. Direct DNA sequencing of the promoter region and all exons and intronic boundaries of the VWF gene identified six mutations likely to be causative of VWD in index cases of nine of the 32 (28%) confirmed type 1 VWD families.

Heteroduplex analysis for the three common HFE variants: methodology, reliability and analysis of over 5000 requests for testing.

Objective: To describe the analysis of over 5300 patient samples for the HFE genotype.

Methods: Blood samples received from hospitals in England, Wales and Ireland were analysed with a single, multiplex PCR using heteroduplex generators for the C282Y, H63D and S65C variants of the HFE gene. PCR products labelled with fluorescent dyes were analysed by capillary electrophoresis.

The prevalence of the cysteine1584 variant of von Willebrand factor is increased in type 1 von Willebrand disease: co-segregation with increased susceptibility to ADAMTS13 proteolysis but not clinical phenotype.

The molecular pathogenesis of type 1 von Willebrand disease (VWD) is uncertain in most patients. We examined 30 type 1 VWD families in the UK Haemophilia Centre Doctors' Organization study. Heterozygosity for Y/C1584 was present in eight of 30 (27%) families and 19 of 76 (25%) individuals with type 1 VWD recruited into the study.

A single, multiplex analysis for all relevant activating NRAS gene mutations using heteroduplex generators.

We describe a multiplex polymerase chain reaction (PCR)-based test that detected all relevant NRAS activating mutations using a single PCR followed directly by electrophoresis. The test uses a Universal Heteroduplex Generator (UHG) to detect exon-2 (codon 61) NRAS mutations in multiplex with an UHG for exon-1 (codons 12 and 13). The method differentiated all 19 relevant mutations in these exons and showed a mutation independent sensitivity of approximately 6%.

Type 1 von Willebrand disease: a possible novel mechanism.

ADAMTS13 (a disintegrin and metalloprotease with thrombospondin motifs) catalyses the proteolysis of von Willebrand factor (vWF). Recent research has indicated that the rate of vWF proteolysis by ADAMTS13 is greater for group O than non-O groups, in the order: group O >/= group B > group A >/= group AB. This, together with the observation that vWF levels are lower for group O than non-O groups, suggested a possible inverse relationship between vWF proteolysis and vWF level.

An amino acid polymorphism in von Willebrand factor correlates with increased susceptibility to proteolysis by ADAMTS13.

The hypothesis that increased ADAMTS13 (a disintegrin and metalloprotease with thrombospondin repeats) activity or increased susceptibility of von Willebrand factor (VWF) to proteolysis by ADAMTS13 may underlie type I von Willebrand disease (VWD) in some patients was investigated. Plasma from 4 patients with type I VWD was cryoprecipitated. ADAMTS13 activity in the VWF-poor cryodepleted fraction was assessed by incubation with purified VWF; susceptibility to proteolysis of the VWF in the VWF-rich cryoprecipitate was assessed by incubation with a normal, group O cryodepleted plasma.

Haptoglobin type neither influences iron accumulation in normal subjects nor predicts clinical presentation in HFE C282Y haemochromatosis: phenotype and genotype analysis.

In the UK, 90% of patients with hereditary haemochromatosis (HH) are homozygous for HFE C282Y, as are one in 150 people in the general population. However, only a minority of these will develop clinical haemochromatosis. Iron loss modifies iron accumulation but so may other genetic factors.

Identification and characterization of a novel gene encoding a SEREX antigen in chronic myeloid leukaemia.

The novel gene encoding Clone 4, previously isolated through the Serological screening of recombinant expression cDNA library (SEREX) in chronic myeloid leukaemia (CML), was characterized. It is localized to chromosome 7 at q22, occupies approximately 4.5 kb of DNA and comprises 4 exons.

Heterogeneous detection of A-antigen on von Willebrand factor derived from platelets, endothelial cells and plasma.

The exact function of the carbohydrate component of von Willebrand factor (VWF) is unknown. ABO blood group antigens are present as integral structures on the oligosaccharide side chains and it has long been recognised that ABO blood group is a determinant of VWF levels. The mechanism for this is not known.

Factor VIIa induced release of von Willebrand factor from human umbilical vein endothelial cells by a tyrosine kinase dependent pathway.

The interaction of FVIIa with surface-bound tissue factor (TF) induces various cellular changes including cytosolic Ca2+ signals. The release of von Willebrand factor (VWF) from endothelial cell stores may be triggered by an elevation in cytosolic free Ca2+, therefore we investigated the effect of rFVIIa on the release of VWF from human umbilical vein endothelial cells (HUVEC). We show here that rFVIIa induces the release of VWF from HUVEC with or without prestimulation with lipopolysaccharide (LPS).

The CpG island in intron 22 of the factor VIII gene is predominantly methylated on the X chromosome of human males.

The inactivation of one of the two X chromosomes in females is a random process associated with methylation principally in CpG islands. The methylation status of a CpG island in intron 22 of the human factor VIII (FVIII) gene was investigated using a novel practical approach. Genomic DNA from men and women was digested with various methylation-sensitive (MS) restriction enzymes, the recognition sequences of which occurred at least once in the FVIII CpG island.