Levels of tumor necrosis factor-alpha (TNF-alpha) and soluble TNF receptors in chronic venous leg ulcers--correlations to healing status.

This study tested the hypothesis that excessive tumor necrosis factor-alpha (TNF-alpha) levels in chronic venous leg ulcers are associated with impaired healing. TNF-alpha was measured by two enzyme-linked immunosorbent assays and a bioassay (KYM-1D4) in paired wound fluid samples collected during the nonhealing and healing phases from 21 human patients with venous leg ulcers. Soluble TNF receptor levels (p55 and p75) were also measured. The levels of immunoreactive TNF-alpha were significantly higher in wound fluid from nonhealing ulcers than in wound fluid from healing ulcers (p < 0.005), whereas the levels of bioactive TNF-alpha were not. Statistical analysis confirmed that TNF-alpha bioactivity relative to the amount of immunoreactive TNF-alpha was downregulated in wound fluid from nonhealing ulcers compared with healing ulcers. The levels of soluble p55 and p75 receptors in wound fluid showed a significant linear correlation (p < 0.001), suggesting a partially coordinated or common regulatory mechanism for the cleavage of transmembrane TNF receptors in chronic venous ulcers in vivo. Although the levels of soluble p75 receptors were significantly higher in nonhealing wound fluid compared with healing wound fluid (p < 0.025), these levels were theoretically inadequate to substantially neutralize the bioactivity of the accompanying TNF-alpha levels on their own. The bioactivity accompanying the elevated levels of immunoreactive TNF-alpha in wound fluid from nonhealing ulcers may have been further down-modulated by an additional mechanism. Because healing was initiated without a significant decline in the level of bioactive TNF-alpha, TNF-alpha-mediated events may not be the key events contributing to the impaired healing seen in chronic venous ulcers.

Acetylation phenotype and cytochrome P450IA2 phenotype are unlikely to be associated with peripheral arterial disease.

The hypothesis that cytochrome P450IA2 (CYPIA2) and/or N-acetyltransferase 2 (NAT2) may be involved in the pathogenesis of peripheral arterial disease was investigated in 90 Australian patients with significant disease and 81 matched control subjects. CYPIA2 and NAT2 phenotypes were determined from urinary metabolite patterns after an oral dose of caffeine. NAT2 phenotype was similar (chi 2 = 0.01; p = 0.98) in both atherosclerotic patients (43.3% rapid) and control subjects (42.0% rapid). CYPIA2 metabolism as measured by the median ratio of (1,7-dimethylxanthine + 1,7-dimethyluric acid)/caffeine was significantly induced by smoking in both patients with atherosclerosis (ratio of 6.5 in nonsmokers and 12.4 in smokers; p < 0.05) and control subjects (ratio of 8.2 in nonsmokers and 14.8 in smokers; p < 0.05), but values in atherosclerotic and control nonsmokers and smokers were similar. Probit transformation of the data revealed a trimodal distribution of ratios in control subjects who were nonsmokers, with 5% classified as poor metabolizers (homozygous rapid) and 95% as extensive metabolizers. The distribution of ratios in control subjects who were smokers was unimodal, whereas among the patients with arterial disease, both smokers and nonsmokers exhibited a bimodal pattern with 8.2% to 16% poor metabolizer and 84% to 91.8% extensive metabolizer phenotypes. When data from both nonsmokers and smokers were combined, the overall proportion of subjects who were poor metabolizers was not significantly different (chi 2 = 1.82; p = 0.18) between control subjects (3.8%) and patients with atherosclerosis (10.6%). Thus biotransformation of environmental or dietary aromatic or heterocyclic amines by NAT2 or CYPIA2 is unlikely to have a significant role in the cause or pathogenesis of peripheral arterial disease.

Investigation and treatment of chronic venous ulcer disease.

INTRODUCTION: The investigation and treatment of chronic venous ulceration continues to present many difficulties for the clinician. The uncertainties relate to the appropriate use of different forms of investigation and whether conservative treatment or surgical treatment should be used. METHOD: A comprehensive search was undertaken of published literature on venous ulceration. RESULTS: The extent of investigations is largely determined by the type of treatment that the patient is either fit to undertake or is prepared to undertake. When conservative treatment only is to be used, detailed investigation of the venous system is not required. The role of surgery to the veins remains unproven in improving the healing of venous ulcers. Surgery to prevent ulcer recurrence has been demonstrated to be of benefit only in patients who have normal deep veins. CONCLUSIONS: Investigations performed on the venous system should be determined by the planned treatment. Many of the operations that have been performed on the venous system still remain unproven in providing a benefit to the healing of venous ulcers and in preventing venous ulcer recurrence.

Qualitative bacteriology and leg ulcer healing.

This study investigated the bacterial profile of leg ulcers in 52 patients attending the Fremantle Hospital leg ulcer clinic. The aim was to identify whether the presence of specific bacterial groups delays healing, whether the bacterial flora changes as ulcers heal and, if so, whether these changes influence healing. The results show that the presence of any one specific bacterial group did not appear to delay healing, although the presence of four or more bacterial groups was associated with delayed healing. This was found to be statistically significant. It was noted that the bacterial flora does change as ulcers heal and that these changes were not related to changes in healing, with the exception of skin flora.

Growth factors, tissue and urokinase-type plasminogen activators in venous ulcers.

Bioimmunoassays for tissue and urokinase-type plasminogen activators (t-pA and u-pA), and enzyme-linked immunosorbent assays (ELISA) for t-pA were performed on biopsies from the edge and base of 15 venous ulcers. TGF-beta 1, bFGF and PDGF were assessed by ELISA in the edge and base of 19 further venous ulcers and 7 biopsies of normal skin. The presence of all three growth factors and u-pA was confirmed immunohistochemically. T-pA was detected using the ELISA and the bioimmunoassay, but was quantified in 3/15 ulcer bases and 4/15 ulcer edges using the bioimmunoassay only. U-pA was measured in all ulcer samples except one. TGF-beta 1 was measured in 13/19 ulcer bases and 9/19 edges, while free TGF-beta 1 was measured in only 2/19 bases and 4/19 edges. Venous ulcer bases contain significantly greater quantities of u-pA, TGF-beta 1, and bFGF than ulcer edges. TGF-beta 1 was never detected in normal skin. There is significantly less bFGF in normal skin than in venous ulcer bases, but not edges (p = 0.013, p = 0.31 respectively, Mann Whitney U-test). There was a good correlation between ulcer edge TGF-beta 1 and time to healing in ten ulcers that healed within six months from the date of biopsy (r = -0.56, p = 0.065, Spearman Rank Correlation). There was a significantly greater amount of ulcer edge bFGF in the ulcers that healed within six months than those that remained unhealed (p = 0.036, Mann-Whitney U-test).(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiology of chronic leg ulcers in Australia.

The aim of this study was to determine the point prevalence of ulceration of the leg in an Australian community. This was a population-based epidemiological study. Two hundred and fifty-nine patients with leg ulceration were identified by health care professionals of all types working in hospitals and private practices, as well as by self referral from patients. The base population in the study area was 238,000. The following data were recorded: age, sex, site of ulceration, duration of ulceration, history of previous ulceration and patient mobility. The point prevalence was 0.11%. The male:female ratio was 1:1.9; however the age related prevalence was similar for both sexes. The age related prevalence of ulceration was similar to that found in two similarly conducted studies in the United Kingdom. The ulcers were a chronic problem with 24% having been present for more than 1 year. Thirty-five per cent of patients had had a problem of ulceration for more than 5 years and 20% had suffered 10 or more episodes of ulceration. Related immobility was a prominent factor with 45% of patients being housebound. Chronic ulceration of the leg is a common recurrent problem in the elderly population and is likely to increase as the population grows. There is a definite need to improve the method of treating this problem.

Australian medical patents granted in the United States in 1984-1999.

OBJECTIVE: To describe all medical patents granted in the United States to Australian-resident inventors between 1984 and 1999. DATA SOURCES: All patent data originated from the US Patent and Trademark Office. Data for 1984-1994 were compiled by CHI Research Inc, and data for 1995-1999 were obtained from the Community of Science website. MAIN OUTCOME MEASURES: Number of medical patents granted in the US to Australian-resident inventors; assignees (owners) of these medical patents; proportion of these medical patents related to biotechnology. RESULTS: From 1984 to 1999, 7835 utility patents were granted in the US to Australian-resident inventors. Of these, 1308 patents (17%) were identified as medical patents; 489 (37%) of these were biotechnology patents. Medical patents account for an increasing proportion of all US patents granted to Australian inventors, increasing from 10% in 1984 to 25% in 1999. Biotechnology accounted for an increasing proportion of medical patents, rising from 10% to 55% between 1984 and 1999. More than half the medical patents are owned by commercial interests, and 33% by only 14 organisations, six of which are universities and their affiliated institutions. CONCLUSION: Only a few organisations account for most of the patenting of medical technology. The inventors and their organisations listed on medical patents could be canvassed when developing government policy and targeted for support in commercialising their medical technology.

Lower levels of PAI-2 may contribute to impaired healing in venous ulcers - a preliminary study.

Plasminogen activators may potentially influence the wound healing processes of cell migration, matrix degradation and cellular adhesion in venous ulcers by their regulation of protease activity. The aim of this study was to assess the levels of plasminogen activators in venous ulcers and to gain preliminary data from healing wounds. The concentrations of u-PA, t-PA, PAI-1 and PAI-2 antigen as well as functional u-PA were assessed in tissue homogenates from 20 chronic venous ulcers, six actively healing venous ulcers and five traumatic wounds. The concentrations of functional u-PA, u-PA antigen and PAI-1 were significantly greater and PAI-2 was significantly lower in the edge and base of chronic venous ulcers compared to adjacent intact skin (P<0.01). Healing wounds had significantly higher functional u-PA at the ulcer edge and higher u-PA antigen concentration in intact skin (P<0.05). PAI-2 levels were significantly higher in the ulcer edge and base in the healing wounds than in chronic venous ulcers (P<0.05). These findings suggest that regulation of protease activity by u-PA and PAI-2 may play a role in the impaired healing of chronic venous ulcers.

Variability and reliability of air plethysmographic measurements for the evaluation of chronic venous disease.

PURPOSE: Air plethysmography (APG) has the potential to help evaluate different treatments for the prevention of recurrence of venous ulcers; however, there are little reported data on the variation and reliability of the different parameters. This study aimed to assess the variation in different APG parameters in patients with chronic venous disease and to evaluate the reliability of APG in test-retest situations. METHOD: Seventeen patients (18 limbs) with chronic venous disease were recruited into this study. Subjects were asked to undergo tests on two occasions, 1 to 6 weeks apart. Three tests were performed at each visit, and three patients had 10 tests performed at one visit. The coefficients of variation were calculated for repeated measurements and test-retest reliability, and the differences between the means of three tests and the 10 tests were also analyzed. RESULTS: The coefficients of variation for the repeated measurements ranged from 7.5% to 27% for the majority of parameters of APG. The differences between the means of three tests and the means of 10 tests were less than 10% in this study. The coefficients of variation of method error were approximately 10% in test-retest measures. CONCLUSIONS: This study has shown that evaluations of calf pump function and venous reflux using APG display variations in repeated measurements and in the test-retest measures. The variations found within patients and on retesting patients on different days suggest that APG is very unlikely to be able to detect small changes in the parameters of venous reflux and calf pump function. It is essential to understand the inherent variation of APG measurements when they are used to assess treatments that are designed to improve venous function.

Biochemical analysis of wound fluid from nonhealing and healing chronic leg ulcers.

The purpose of this study was to determine the biochemical composition of fluid taken from chronic wounds, to compare these values with that of serum, and therefore to assess whether the wound fluid is representative of the extracellular environment of the wound. Paired wound fluid and blood samples were collected from eight patients with chronic leg ulcers in a nonhealing and healing phase. Wound fluid and serum samples were screened for a profile of general biochemical analyses, including electrolytes, lactate, glucose, and protein analyses. Electrolyte levels were essentially identical in wound fluid and serum samples. Lactate and lactate dehydrogenase levels were significantly greater and glucose and bicarbonate levels were significantly lower in wound fluid when compared with the paired serum samples. Albumin and total protein levels in wound fluid were on average half those of serum levels. In this small sample of eight patients, wound fluid collected from chronic leg ulcers is an exudate with the biochemical composition expected in extracellular fluid. In addition, bicarbonate and glucose levels increase and C-reactive protein levels decrease in wound fluid, but remain unchanged in serum, during healing. These results suggest changes in the state of hypoxia and the inflammatory process in the healing wound.

Mitogenic activity and cytokine levels in non-healing and healing chronic leg ulcers.

The cause of impaired healing in chronic leg ulcers is not known. However, recent attempts to modify the healing process have focused on adding growth factors to stimulate healing and have failed to produce dramatic improvements in healing. This study used a unique model of chronic wound healing in humans to obtain wound fluid samples from chronic venous leg ulcers that had changed from a nonhealing to a healing phase. These samples were used to assess cytokine and growth factor levels, and mitogenic activity in these nonhealing and healing chronic wounds. The pro-inflammatory cytokines interleukin-1, interleukin-6 and tumor necrosis factor-alphawere found to be present in significantly higher concentrations in wound fluid from nonhealing compared to healing leg ulcers. There were detectable levels but, no significant change in the levels of platelet derived growth factor, epidermal growth factor, basic fibroblast growth factor or transforming growth factor-betaas ulcers healed. Wound fluid was added to fibroblasts in vitro to assess mitogenic activity. There was a significantly greater proliferative response to healing wound fluid samples compared to nonhealing samples. These results suggest that healing may be impaired by inflammatory mediators rather than inhibited by a deficiency of growth factors in these chronic wounds.

Changes in calf muscle function in chronic venous disease.

The aim of this study was to assess calf muscle function in patients with chronic venous disease and recently healed venous ulcers. Forty-nine consecutive patients with recently healed proven venous leg ulcers and 20 age- and sex-matched control subjects were entered into this study. Both patients and control subjects underwent duplex scan evaluation of their leg veins and isokinetic measurement for calf muscle strength and endurance. Calf muscle function was significantly impaired in patients with chronic venous disease compared with control subjects. Both peak torque/body weight (strength), P = 0.049 (CI 0.3-18.4%) and total work (endurance), P = 0.05 (Cl 6.01-97.6 Nm) were reduced. This study has shown that patients with chronic venous disease have a significant impairment of calf muscle function compared with healthy control subjects. This study suggests that there is a need to evaluate whether a programme to improve muscle strength may be of benefit in both healing and preventing the recurrence of chronic venous ulcers.

The Australian polidocanol (aethoxysklerol) study. Results at 2 years.

BACKGROUND: An ongoing study of the safety and effectiveness of polidocanol by 98 investigators in Australia infecting 16,804 limbs over 2 years. OBJECTIVE: To evaluate the complications of polidocanol and compare its effectiveness and complications with sodium tetradecyl sulphate (STD) and hypertonic saline. METHODS: A single-arm prospective study of polidocanol complications and its effectiveness as a sclerosant was performed. This was compared with each investigator's previous experience with other sclerosing agents. Patients had either varicose veins or venule ectasias and/or spider veins (telangiectasia). A total of 16,804 limbs were injected by 98 investigators. Sclerotherapy was performed with 0.5% or 1% polidocanol for telangiectasias or spider veins, and with 3% polidocanol for varicose veins. The effectiveness of the sclerotherapy and any complications were reported during a 2-year period. RESULTS: There were very few complications reported with polidocanol. There were no reported deaths or anaphylaxis. The investigators with previous experience of other sclerosants considered that the effectiveness of polidocanol was superior to STD (85%) and hypertonic saline (84%). Ninety percent of investigators considered that polidocanol had less frequent complications than STD, and 80% considered that these were less severe. Seventy-four percent considered that polidocanol had fewer side effects than hypertonic saline, and 74% considered that these were less severe. CONCLUSIONS: Polidocanol is an effective sclerosant that has few complications.

Effect of exercise on calf muscle pump function in patients with chronic venous disease.

BACKGROUND: Musculoskeletal dysfunction may be associated with poor calf muscle pump function in patients with chronic venous ulceration. The aim of this study was to evaluate the effects of physical exercise on calf muscle pump function. METHODS: Twenty patients were recruited into a 6-week intensive exercise programme. Calf muscle function and calf muscle pump function were assessed using an isokinetic device and air plethysmography respectively, before and after the exercise programme. RESULTS: There was significant improvement in calf muscle pump function, measured as increased ejection fraction and decreased residual fraction (P < 0.05); however, venous reflux was not altered (P > 0.05). Calf muscle strength and endurance parameters all increased, but not significantly (P > 0.05). CONCLUSION: Poor calf muscle pump function in patients with chronic venous ulceration can be improved by physical exercise.

Changes in the apparently normal limb in unilateral venous ulceration.

Forty-seven patients with unilateral venous ulceration have been investigated to determine if any abnormalities were present in the contralateral limbs which had not had lipodermatosclerosis or ulceration. Ascending phlebography in the non-ulcerated limbs showed post-thrombotic changes in 28 per cent and incompetent lower leg communicating veins in 19 per cent. This incidence was not significantly different to the limbs with healed ulceration (45 and 23 per cent respectively, chi 2 test, P = 0.10). Half volume refilling time measured by foot volumetry suggested that 79 per cent of the non-ulcerated limbs had evidence of deep vein incompetence or incompetent lower leg communicating veins, which was again similar to the incidence in the previously ulcerated limbs (85 per cent). Transcutaneous oxygen readings, expressed as a ratio of a reading at a standard site in the gaiter region of the leg over a reading from the upper arm, were significantly lower in non-ulcerated limbs (mean 0.84 +/- 0.26 s.d.) than in a cohort of age and sex matched controls (mean 1.02 +/- 0.14, Student's t test, P less than 0.001), and significantly higher than in previously ulcerated limbs (mean 0.68 +/- 0.31, P less than 0.01). Abnormalities in venous anatomy and function have been shown, in conjunction with evidence of reduced oxygen diffusion, through the gaiter skin before overt skin changes develop.

Calf pump function in patients with healed venous ulcers is not improved by surgery to the communicating veins or by elastic stockings.

Calf muscle pump function was assessed in 41 limbs after venous ulcers had healed. Treatment was then randomized either to ligation of incompetent lower leg communicating veins and ablation of incompetent superficial veins combined with permanent graduated compression elastic stockings, or to graduated compression elastic stockings only. Half volume refilling time (TV1/2) and relative expelled volume (EVrel) measured on foot volume plethysmography were used to assess calf muscle pump function. This was repeated after 12 months. The initial TV1/2 and EVrel were significantly lower than for normal limbs. There was no significant improvement in TV1/2 in either treatment group (Student's t test, P = 0.78, P = 0.19). EVrel did not improve significantly in limbs treated with elastic stockings alone (P = 0.94), but there was a slight but significant improvement in EVrel in limbs treated with surgery and elastic stockings (P = 0.048); however, this was still significantly below the normal range (P less than 0.001). In limbs without phlebographic evidence of post-thrombotic changes, treated with the combination of surgery and elastic stockings, there was a significant improvement in EVrel (P = 0.035), but no improvement was found in limbs with post-thrombotic changes. This small but significant improvement in EVrel in limbs without post-thrombotic changes treated by surgery and elastic stockings may explain the reduced incidence of reulceration that has been found following surgical eradication of the superficial and communicating veins.

Aetiology of chronic leg ulcers.

This study was undertaken to determine the relative prevalence of the factors causing chronic ulceration of the leg in the general population. Two hundred and fifty-nine patients with chronic ulceration of the leg were found on screening a Western Australian population of 238,000. (The prevalence of chronic ulceration of the leg was 1.1 per 1000 population.) Two hundred and forty-two of these patients (93%) with 286 chronically ulcerated limbs were fully assessed to determine the factors contributing to ulceration. In 239 limbs (84%) ulceration involved the leg; in these limbs venous disease was the most prevalent cause of ulceration (160 limbs). Arterial disease was found in 66 limbs, with both venous and arterial disease present in 35 limbs. Rheumatoid arthritis was a causative factor in 27 limbs and diabetes was found with 29 limbs with ulceration involving the leg. In 47 limbs (16%) ulceration was confined to the foot; arterial disease (35 limbs) and diabetes (23 limbs) were the most prevalent causes of ulceration in these limbs. Venous disease was infrequent (three limbs). No disorder of the circulation was found in 48 limbs (20%) with ulceration involving the leg, and in 58 (20%) of all ulcerated limbs. More than one aetiological factor was present in 93 limbs (33%). A cause for ulceration was not found in 10 limbs (3.5%).

Incisional hernias are more common in aneurysmal arterial disease.

OBJECTIVE: To test the hypothesis that incisional hernia was a more frequent complication following aortic reconstructive surgery in patients with aneurysmal as opposed to occlusive aortic disease. DESIGN: A retrospective review. MATERIALS AND METHODS: All patients having aortic reconstructive surgery at a teaching hospital between 1988 and 1992 were identified and recalled to be examined for evidence of an incisional hernia. RESULTS: Of the 134 patients having aortic reconstructive surgery, 87 were available to be examined by an independent clinician. The overall incisional hernia rate was 28%. Patients with aneurysmal disease were significantly more likely to develop an incisional hernia after elective surgery than patients with occlusive disease (p = 0.04). None of the other variables investigated, including age, chronic obstructive airways disease, diabetes, smoking, wound infection, obesity, length of intensive care unit stay and number of units of blood transfused, were significantly related to the complication of incisional hernia. CONCLUSION: Incisional hernia is a common complication of aortic reconstructive surgery, especially in patients with aneurysmal disease.

Malignancy in chronic leg ulcers.

OBJECTIVE: To evaluate the frequency of malignant ulcers in patients presenting with leg ulcers. DESIGN: A descriptive study from data collected between July 1988 and June 1995 from 981 patients (2448 ulcers) attending a leg ulcer clinic. SETTING: A specialised leg ulcer clinic at a tertiary teaching hospital. SUBJECTS: 43 patients with 55 malignant skin lesions. OUTCOME MEASURES: Tissue biopsies in ulcerated lesions that suggested malignancy or were not responding to appropriate treatment. RESULTS: Forty-three patients were found to have malignant lesions on the legs, giving a frequency of malignant ulcers of 4.4 per 100 leg ulcer patients, or 2.2 per 100 leg ulcers. Seventy-five per cent of the malignant ulcers were basal cell carcinoma and 25% were squamous cell carcinoma. CONCLUSIONS: Malignant skin changes are common in chronic leg ulcers. A biopsy should be taken from all suspicious ulcers or ulcers that do not respond to appropriate treatment.