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Biomedical subjects

D F Williams

Publications and source records attributed to D F Williams.

At least 181 records · Page 10Linked to original sources
PubMed1977

Titanium as a metal for implantation. Part 1: physical properties.

The scientific basis for the use of titanium and its alloys in implant surgery is reviewed, including the structural metallurgy, mechanical properties, corrosion resistance and biocompatibility. The clinical application are discussed in relation to orthopaedic, oral, plastic and reconstructive and cardiovascular surgery.

Corrosion↗
PubMed1977

Enzyme-accelerated hydrolysis of polyglycolic acid.

In a preliminary study of the enzyme-polymer interactions, the role of 15 enzymes in the in vitro hydrolysis of polyglycolic acid has been investigated. Carboxypeptidase A, alpha-chymotrypsin, clostridiopeptidase A and ficin increase the rate of hydrolysis of this synthetic polymer, illustrating the ability of enzymes to influence polymer degradation.

Biocompatible Materials↗
PubMed1976

Biomaterials and biocompatibility.

This review attempts to assess the present status of biomaterials, especially in relation to their interaction with tissue. The terms biomaterial and biocompatibility are defined and both the present areas of clinical application and the requirements of biomaterials for these applications discussed. The types of biomaterials in clinical use and those under development are briefly described. Problems associated with implant functionality are covered, dealing with fatigue, wear and membrane permeability. Of more importance are the problems relating to biocompatibility and metallic corrosion, polymer and ceramic degradation, local tissue changes, systemic effects, infection, implant loosening, blood compatibility and the assessment of biocompatibility.

Alloys↗
PubMed1976

Hair sampling for chromium content following Charnley hip arthroplasty.

The chromium content of hair has been studied by neutron activation analysis of samples from 62 patients following a Charnley unilateral or bilateral hip arthroplasty by an artificial joint of stainless steel against polyethylene, inserted three to five years previously. The patients lived in the North Wales area of the British Isles. Hair chromium content was also studied in 51 control subjects of similar age to that of the patients, from the same geographical area and often from the patients' own households. Chromium content was recorded as parts per million (ppm) of hair weighed and analyzed in the state received, without preliminary ashing or chemical "washing" of the samples in the laboratory. Fifty of the 51 control subjects showed less than 2 ppm chromium in hair; one showed 2-5 ppm; none showed more than 5 ppm. Fifty-nine of the 62 patients showed less than 2 ppm chromium in hair; three showed 2-5 ppm; none showed more than 5 ppm. Attention is drawn to certain practical aspects when collecting hair samples for chromium analysis. The use and validity of hair sampling as one method of screening for systemic chromium accumulation following implant surgery is discussed. The method may be a useful adjunct to monitoring of chromium levels in blood samples. In this preliminary study, hair sampling has given no evidence of any major risk of systemic chromium accumulation in patients using a Charnley arthroplasty for periods of up to five years; no conclusion can be made concerning periods longer than this. The findings do not exclude systemic reactions of the hypersensitivity type, since this type of reaction could develop to only small amounts of chromium.

Acetabulum↗
PubMed1975

The effect of metal clips on the tensile properties of healing skin wounds.

The effects of nylon sutures and metal skin clips on the tensile properties of healing skin wounds have been studied in the pig. Wounds closed with clips have significantly poorer mechanical properties at 5, 7 and 14 days after wounding than similar wounds in the same animal closed with interrupted nylon sutures. This difference increased progressively with the period of retention of the clips. It is also shown that in equivalent groups of 14-day wounds, those in which clips were retained after the seventh day had a lower tensile strength, poorer ability to absorb energy and a lower elastic modulus than similar wounds where clips had been removed early. No such adverse effect was noted with nylon sutures.

Animals↗
PubMed1975

Future prospects for biomaterials.

Biomaterials have many uses in medicine and surgery but success in their use is often difficult to achieve. In this paper some of the deatures that contribute to the success or failure of biomaterials are discussed in relation to a hypothetical implant situation. The phenomena of biomaterial-tissue interfacial reactions, wear, prosthesis instability, infection, hypersensitivity and carcinogenesis are considered. Emphasis is given both to the causes and clinical significance of these phenomena and interpreted in terms of the furture prospects for the biomaterials.

Alloys↗