W.H. Reid

Non-pressure treatment of hypertrophic scars☆

A silicone gel (Dow Corning X7-9119) has been successfully used in the management of hypertrophic scars. The gel softens and reduces scars in a shorter time period than pressure therapy. Relevant properties of the material and its mode of action have been investigated. The mode of action is unknown, but it is not due to pressure, temperature, oxygen tension or occlusion.

The preclinical evaluation of the water vapour transmission rate through burn wound dressings

The control of evaporative water loss, following burn injury, is of major importance to the overall condition of the patient, whether this control is by natural eschar or by a dressing. It is therefore important to preclinically determine the water vapour transmission rate of these dressings, firstly to make comparisons between different materials and secondly to screen prototype materials, under controlled conditions. A preclinical (in vitro) technique is described and the results are given for several commercially available dressings which encompass foam, film and hydrogel material categories.

Burn wound dressings—a review

Man has dressed wounds since life began many millions of years ago. Since this time many materials have been devised for the intention of dressing wounds. This review indicates the vast range presently available, providing a starting point for those seeking information on this subject.

Chondroitin-6-sulphate incorporated into collagen gels for the growth of human keratinocytes : the effect of cross-linking agents and diamines

This study demonstrates the effect of the glycosaminoglycans, hyaluronic acid and chondroitin-6-sulphate (Ch6SO4), diamines and a carbodiimide cross-linking agent on the growth of human epidermal cells on collagen gels. Ch6SO4 incorporated into collagen gels stimulated cell growth rate, but the effect was found to be inconsistent. We found that approximately 50% of the incorporated Ch6SO4 in the gels leached out into the growth medium after the first 3 d in culture, and this is thought to lead to the inconsistent cell growth response. In order to minimize the elution of Ch6SO4 from the gels and thereby maximize its effect on the growth of the keratinocytes, 1-100 micrograms ml-1 Ch6SO4 was added in the medium. The results showed that Ch6SO4 at these concentrations in the medium did not stimulate the cell growth on either plain collagen gels or gels containing 20% Ch6SO4. As an alternative strategy, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and diamines (putrescine or diaminohexane) were used to immobilize Ch6SO4 onto the collagen gels and to cross-link the gels. The cross-linking process partially prevented the elution of Ch6SO4 from the gels. Interestingly, only putrescine, not diaminohexane, promoted the growth of keratinocytes on the cross-linked plain collagen gels. We proposed to develop an artificial skin substitute containing putrescine as a growth factor for the human epidermal cells.

TRENDS IN BURN ADMISSIONS IN SCOTLAND DURING 1970-92

This retrospective study involved analysis of the data of the inpatients discharged with a diagnosis of burns, from various hospitals in Scotland, during the period 1970-92. There were 51,350 such inpatients all over Scotland, with an average annual rate of 2233 cases. Overall burn incidence in actual numbers was 43.7 per cent in < 15 year olds, 41.2 per cent in 15-64 year olds and 15.1 per cent in > or = 65 year olds. Burn rates per 100,000 population were highest in < 15 year olds and lowest in 16-64 year olds. The pattern of burn admissions has changed. Since 1987 the highest numbers of burn inpatients were the 16-64 year olds, followed by children, then the elderly. There has been a gradual but sustained fall in burns admissions in all age categories. The downward trend was statistically significant (t = 8.48, 21 d.f., P < 0.001). Though the population of the elderly (> or = 65 year olds) increased by about 13 per cent, the burn admissions and all deaths due to burns did not reveal an upward trend. The population of the old (81+ year olds) increased by 60 per cent during the same period. The incidence of burns was above average when > 80 year olds were considered separately, approaching the levels found in children. However the rate and incidence of burns in the 65-80 year olds resembled that of the younger age group (16-64 year olds). The total number of deaths due to burns and/or smoke inhalation has declined in all age groups and the decline has been statistically significant (chi-squared = 19.62, 1 d.f., P < 0.001). Maximum number of deaths occurred in > or = 65 year olds (44 per cent), followed closely by 16-64 year olds (43.5 per cent), and 12.5 per cent of deaths in adolescents and children. The decline was due to improved management of burns and a decrease in the number of patients having large body surface area burns.

A practical technique for the thermographic estimation of burn depth: A preliminary report

Abstract A low-cost heat-sensitive television camera has been evaluated for the thermographic estimation of burn depth in two short clinical trials. Patches of moisture on the surface of a burn were found to produce thermal artefacts which dominated the first trial. Spraying the wound to give a uniformly wet surface was completely successful in removing these artefacts in the second trial. Using this technique, thermography correctly identified the extent of all deep burns.

Arterial Surgery in Intermittent Claudication

The results of a survey of 302 operations in 277 patients during 1959-70 are presented, and an additional 69 operations during 1971 are included in the mortality figures. Operative mortality (1968-71) was 0·9% in 113 aortoiliac operations and nil in 96 femoropopliteal operations. Immediate patency rates on dismissal from hospital exceeded 95%, and the five-year patency rate for aortoiliac operations was just over 70% and for femoropopliteal operations 60%.

Confocal laser-scanning microscopy for determining the structure of and keratinocyte infiltration through collagen sponges

The development of artificial skin substitutes based on cultured cells and biomaterials such as collagen requires an understanding of cellular interactions with the substrate. In this study, human keratinocytes were cultured on the surface of collagen sponges, and confocal laser-scanning microscopy (CLSM) was used to assess both the microstructure of the sponge, and the cell morphology and distribution throughout the sponge. It was found that the pore size increased with increasing depth into the sponge. Both pore size and fiber thickness increased during incubation for up to 10 days at 37 degrees C in culture medium in the absence of cells. This latter effect was not observed when the sponges were incubated in distilled water. Keratinocytes penetrated into the sponge even after only 3 days in culture. By 10 days in culture, the cells had penetrated to the maximum depth that could be examined (120 microns from the sponge surface). In the presence of cells, the inner structure of the collagen sponge had altered after 10 days in culture, with the collagen fibers becoming thicker, and pore geometry less regular. The mechanism responsible for this is unknown at present. Although the presence of the keratinocytes increases distortion of the sponge structure, factors from the medium itself also contribute to this effect. CLSM is a powerful tool for assessing cellular interactions with bioimplants, providing both qualitative and quantitative information. It offers many advantages over scanning electron microscopy (SEM) and histological techniques. CLSM minimizes the time-consuming, extensive preparation of samples required with the latter two methods, and allows noninvasive serial optical sectioning of intact samples.

An in vitro assessment of wound dressing conformability

An in vitro assessment technique has been developed to determine the conformability of wound dressings. The technique employed is based on an inflation technique which provides a measurement of the minimum radius of curvature which a specific dressing will adopt under pressure. A pressure of 40 mmHg was chosen as this had been shown to be the maximum tolerable pressure before the occurrence of tissue breakdown. This radius is then matched to the natural radii of the body surfaces and an assessment of conformability can be made. A series of commercially available dressings have been assessed with respect to their conformability, and to the enhancement of their conformability due to viscoelastic creep behaviour.

Endovascular Significance of the External Carotid Artery in the Treatment of Cerebrovascular Insufficiency

Purpose: To present illustrative cases that demonstrate the feasibility and clinical benefits of endovascular treatment of external carotid artery (ECA) stenoses in patients with occluded internal carotid arteries (ICA). Case Reports: Three patients with symptoms of cerebrovascular insufficiency and a stenosis of the ECA in the presence of occluded ICAs and diseased vertebral arteries were treated successfully by percutaneous stent or stent-graft implantation with and without cerebral protection. Conclusions: The ECAs play an important role in providing collateral blood supply to the brain through the many connections between branches of the ECA and cranial branches of the ICA and vertebral arteries. If these important pathways of collateral cerebral blood flow become diseased, ischemic symptoms become apparent. We recommend an endovascular procedure as a potential alternative to surgical endarterectomy of the ECA in patients with severe extracranial arterial disease.