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Biomedical subjects

G W Cherry

Publications and source records attributed to G W Cherry.

66 records · Page 4Linked to original sources
PubMedDate not supplied

Hyaluronan, heterogeneity, and healing: the effects of ultrapure hyaluronan of defined molecular size on the repair of full-thickness pig skin wounds.

The extracellular matrix macromolecule, hyaluronan, is thought to modulate wound healing. However, the molecular size of hyaluronan and contaminating associated proteins may be important determinants of these effects. We have examined the results of seven daily topical treatments of full-thickness skin wounds in pigs with ultrapure hyaluronan of defined molecular size. High molecular weight hyaluronan (>1000 kd) enhanced, whereas low molecular weight hyaluronan decreased, the rate of early wound contraction as compared with intermediate hyaluronan (molecular weight = 100 kd) and saline solution controls. Fracture strength at 21 days was reduced by high and intermediate molecular weight hyaluronan but not by low molecular weight hyaluronan. Wound perfusion, measured by means of a scanning laser-Doppler technique as a noninvasive indicator of angiogenesis, showed depression by high and intermediate molecular weight hyaluronan on day 3, but all forms of hyaluronan caused elevated blood flow on day 7. The architecture of granulation tissue in this wet healing model was highly organized, but no gross histologic differences were seen because of treatment. Different molecular species of hyaluronan have differential effects on contraction, angiogenesis, and the evolution of wound strength. Where hyaluronan is used as a treatment or vehicle for wounds, its precise composition should be specified.

Journal Article↗
PubMedDate not supplied

In vitro studies on the antioxidant and growth stimulatory activities of a polyphenolic extract from Cudrania cochinchinensis used in the treatment of wounds in Vietnam.

The leaves of Cudrania cochinchinensis, a Vietnamese folk remedy, have been suggested as a beneficial agent for wound healing. Animal studies and clinical observations in Vietnam have shown positive wound healing activity. We studied the effects of a polyphenolic extract from the plant on the proliferation of cells in culture and their response to oxidative damage by hydrogen peroxide. Fibroblasts were incubated with different concentrations of the extract in 0.4% fetal calf serum, and proliferation was monitored by a colorimetric assay. Cell damage was induced by exposure to hydrogen peroxide 7 x 10(-5) mol/L for 3 hours. The same colorimetric assay was used to assess cell damage and the protective effect of the extract against oxidative damage. The extract at low concentrations (0.1 to 5 microg/ml) had a stimulatory effect on fibroblast growth. The effect was significant by 7 days after the addition of the extract and was strongest at a concentration of 1 microg/ml of extract (p< or = 0.01). The extract at concentrations of 5 or 50 microg/ml protected fibroblasts and endothelial cells against hydrogen peroxide-induced damage. Pretreatment with the extract or exposure to extract simultaneously with hydrogen peroxide gave only partial protection against oxidative damage, whereas a combination of the two treatments gave complete protection (p< or = 0.005). Stimulation of fibroblast proliferation and protection of cells against destruction by inflammatory mediators may be ways in which the polyphenolic substances from the plant, Cudrania cochinchinensis, contribute to wound healing.

Journal Article↗
PubMedDate not supplied

Epidemiological study of chronic dermal ulcers in China.

A total of 30,000 hospitalized surgical patients in 15 hospitals were screened for chronic ulcers. A total of 489 patients with chronic dermal ulcers were found with their major causes of ulceration including traumatic wounds, infections, diabetes mellitus, and venous diseases. Patients with chronic ulcers following trauma and infection comprised 67.48% of the total patient population. The incidence of diabetic ulcers and venous ulcers was 4.91% and 6.54% respectively. Sites of ulceration differed with different etiological factors. The percentage of chronic dermal ulcers in the lower extremities, upper extremities, thorax and abdomen, back, and head was 63.10%, 17.93%, 7.76%, 4.83% and 6.38% respectively. Of the 489 patients with chronic ulcers, 183 were farmers (37.42%), and 131 were workers (26.79%). Chronic dermal ulcers were more common in men than in women, but there was no significant difference in the sex-related prevalence. According to these data from different hospitals, the incidence of chronic ulcers in patients hospitalized for surgery was 1.5% to 3.0%. These data have primarily shown the prevalence and clinical characteristics of chronic ulcers in hospitalized patients in China. These data may not be consistent with reports from other countries. Significant differences in etiological factors of ulceration, professional distribution of patients with chronic dermal ulcers, and treatment methods were found when compared with reports of studies conducted in developed countries. Our results will benefit not only additional basic research, but these data will also be useful in preventing and managing chronic wounds in developing countries.

Adolescent↗
PubMedDate not supplied

Effects of chronic wound fluid on the bioactivity of platelet-derived growth factor in serum-free medium and its direct effect on fibroblast growth.

The fate of biologically active proteins applied to chronic wounds is almost totally unknown. Growth factors may be degraded by proteases, which are produced by both inflammatory and skin cells and by resident bacteria. However, there has been little work on the effect of chronic wound fluid on the activity of growth factors. A bioassay method has been chosen to examine the effect of incubation of platelet-derived growth factor with chronic wound fluid from leg ulcers on the in vitro growth of human dermal fibroblasts. Human dermal fibroblasts were cultured in serum-free medium, and a dose-response curve for proliferation in response to platelet-derived growth factor was obtained. Wound fluid was collected under occlusive dressings from five patients with chronic leg ulcers. Platelet-derived growth factor was incubated with chronic wound fluid at 37 degrees C for 4 hours, and the reactions arrested by snap freezing. The resultant solutions were tested for their ability to promote fibroblast proliferation. A colorimetric assay was used to monitor changes in the platelet-derived growth factor mitogenicity. The results showed that, in our standard culture conditions, chronic wound fluid always stimulated fibroblast proliferation, and, in most cases, incubation of platelet-derived growth factor with chronic wound fluid increased the stimulation compared with that produced by platelet-derived growth factor or chronic wound fluid alone.

Aged↗
PubMedDate not supplied

Stimulation of fibroblast growth in vitro by intermittent radiant warming.

A number of clinical studies have suggested that radiant heat improves the healing of selected acute and chronic wounds. The purpose of this study was to investigate in vitro the effect of intermittent radiant heating on the growth of human skin fibroblasts using a radiant heat-producing dressing with a designated temperature of 38 degrees C. In initial experiments cells were seeded in six well-plates, maintained in culture at 33-34 degrees C, and warmed daily for three cycles of 1 hour with 1.5 hour intervals. Changes in cell growth and metabolism were determined in sets of triplicate wells by cell counts and a colorimetric assay before and after one week's treatment. After eight days the number of cells in the radiant heat-treated group was 30% higher and the metabolic activity 47%- 90% higher than in the control group. In quiescent fibroblasts which had been maintained for four weeks in low-serum medium, the warming regime completely prevented the decrease in cell number observed in control cells. Our findings suggest that the stimulation of cell proliferation induced by intermittent heating in vitro may indicate a possible mechanism contributing to in vivo effects.

Adolescent↗
PubMedDate not supplied

Simple biochemical markers to assess chronic wounds.

We investigated the potential for the biochemical analysis of chronic wound fluid to predict healing using simple and widely available analytes in an out-patient clinic setting. Wound fluid was collected from 12 patients attending a leg ulcer clinic and analyzed for a variety of analytes, including lactate, total protein, and albumin. Twelve weeks after collection the wound was assessed for healing (defined as complete healing or greater than 50% reduction in wound size). The median total protein (44.3 +/- 8.8 g/l) and albumin (25.0 +/- 2.3 g/l) concentrations in exudate collected from four healing wounds were significantly higher (p < 0.05) than in exudate from eight nonhealing wounds (median total protein 29.7 +/- 7.6 g/l, median albumin 17.0 +/- 4.3 g/l). No significant difference was observed for lactate. A second specimen of wound fluid was collected from four of the patients (three nonhealing and one healing). The protein analysis confirmed the pattern observed for the first collection: nonhealing wounds had total protein and albumin which remained low compared to healing wounds. No wound with an exudate albumin of less than 20 g/l healed. Both total protein and albumin are stable analytes which can be easily measured in any laboratory and may offer a simple biomarker of healing in chronic wounds.

Aged↗
PubMedDate not supplied

Effects of an aqueous extract from the leaves of Chromolaena odorata (Eupolin) on the proliferation of human keratinocytes and on their migration in an in vitro model of reepithelialization.

Eupolin ointment, prepared from the leaves of Chromolaena odorata, has been shown to promote the healing of soft tissue wounds and burns in Vietnam. However, the mechanism by which this agent affects cells involved in the wound healing process is unknown. Cultured human keratinocytes were used in this study to investigate the effects of the Eupolin extract in vitro on processes involved in wound reepithelialization. Keratinocyte proliferation was monitored by a colorimetric assay and migration by the closure of a denuded area scratched in a confluent monolayer. Human keratinocyte proliferation was stimulated by low concentrations of the extract (from 0.1 to 5 microg/ml), cell differentiation by higher concentrations (50 to 300 microg/ml), and migration by intermediate concentrations (5 to 60 microg/ml). The increased proliferation and migration of human keratinocytes observed in vitro might explain, in part, the beneficial effects that have been observed in the clinic.

Analysis of Variance↗
PubMedDate not supplied

Bandaging in the treatment of venous ulcers: a European view.

The principal treatment of venous ulcers in ambulatory patients in bandaging. The physiological rationale for this treatment is to improve the venous hemodynamic abnormality caused by prolonged venous hypertension due to limb venous valvular incompetency. Correct bandaging results in the reduction of limb edema and ulcer healing. A number of different bandages and combined bandaging regimens are used in the treatment of venous ulceration. Recently the European Tissue Repair Society has defined different types of bandages based on their function into four groups: (1) Extensible bandage; (2) Elastic bandage; (3) Compression bandage; and (4) Support bandage. The ability of a bandage to produce a gradient compression starting at 35 to 45 mmHG at the ankle and reducing as the bandage approaches the knee is stated in the literature as a goal of bandaging. Our studies and others have shown that routine measurements of limb circumference as an indicator of edema reduction is another way of monitoring the efficacy of the results of bandaging since edema reduction and control is associated with improved ulcer healing.

Bandages↗