Showing papers by "Alan R. Giles published in 1991"

Recurring mutations at CpG dinucleotides in the region of the von Willebrand factor gene encoding the glycoprotein Ib binding domain, in patients with type IIB von Willebrand's disease.

Abstract: The mutant von Willebrand factor (vWf) molecule in type IIB von Willebrand's disease (vWd) has an increased binding affinity for the platelet receptor glycoprotein Ib (GpIb). In previous studies we have confirmed genetic linkage of this phenotype to the vWf gene and in this report we document three recurring missense mutations in the region of the gene that encodes the GpIb binding domain. Two families with type IIB vWd were found to have an arginine to tryptophan substitution at residue 543, three families had a valine to methionine substitution at residue 553, and one kindred had an arginine to glutamine change at amino acid 578. None of these sequence changes were found in 200 normal vWf genes and within each of the six families the mutations were only found in affected subjects. This is strong circumstantial evidence in support of these substitutions representing the disease causing mutations in these families. All three of these substitutions have occurred at CpG dinucleotide sequences, and their polymorphic associations indicate that they represent recurring new mutations. Missense mutations at these sites may represent the underlying genetic pathology in a large number of type IIB vWd families.

The Use of Animal Models to Evaluate Proteins Produced by Recombinant Technology

Abstract: Although the ultimate test of a recombinant protein’s safety and efficacy for its intended use rests with rigorous evaluations in humans, pre-clinical testing of new therapies in animals is required by many regulatory jurisdictions to provide both the justification for human study and information upon which the design of these studies will be based. Moreover, in more traditional pharmaceuticals, In vivo evaluations in appropriate animal models have played an essential role in primary development in many cases. Although frequently modelled on “natural” products, recombihant proteins are no exceptions. Given the relatively contrived nature of the expression systems used, minor variations in their molecular biology, eg. carbohydrate composition, may result in functional consequences that cannot necessarily be excluded by In vitro study alone. Moreover, the very technology permits the deliberate manipulation of the protein structure designed to improve functional performance such as increasing the t1/2 in vivo. The success or failure of such endeavours may be more safely and, in many cases, effectively evaluated in appropriate animal models prior to human study. The questions that may be addressed by such an approach fall into two general areas.