Experience with a novel efalizumab-based immunosuppressive regimen to facilitate single donor islet cell transplantation.

Islet transplantation is an experimental therapy for selected patients with type 1 diabetes (T1DM). It remains limited by immunosuppressive drug toxicity, progressive loss of insulin independence, allosensitization and the need for multiple islet donors. We describe our experience with an efalizumab-based immunosuppressive regimen as compared to the prevailing standard regimen, the Edmonton protocol. Twelve patients with T1DM received islet transplants: eight were treated with the Edmonton protocol; four were treated with daclizumab induction, a 6-month course of tacrolimus, and maintenance with efalizumab and mycophenolate mofetil. The primary endpoint was insulin independence after one islet infusion. Only two Edmonton protocol treated patients achieved the primary endpoint; six required islets from multiple donors, and all experienced leukopenia, mouth ulcers, anemia, diarrhea and hypertransaminasemia. Four became allosensitized. All patients treated with the efalizumab-based regimen achieved insulin independence with normal hemoglobin A1c after a single islet cell infusion and remained insulin independent while on efalizumab. These patients experienced significantly fewer side effects and none became allosensitized. Trial continuation was terminated by withdrawal of efalizumab from the market. These data suggest that this efalizumab-based regimen prevents islet rejection, is well tolerated, and allows for single donor islet transplantation.

Intracellular killing of Candida albicans by human polymorphonuclear leucocytes: comparison of three methods of assessment.

Three different methods, [3H]uridine uptake, viable count and 51Cr-release were used to assess the intracellular survival of a strain of Candida albicans, 19321, which was lethal for mice injected intravenously. Intracellular survival 1 h after ingestion ranged from 50 to 80% depending on the method employed and the detergent used to lyse the phagocytes. Inhibition of uridine uptake by detergents used to lyse the phagocytes led to difficulty in assessment of intracellular killing by this method.

Occlusive dressings: a microbiologic and clinical review.

This review discusses the microbiology of normal skin and wounds and examines the rates of infection reported under both conventional (nonocclusive) dressings and all occlusive dressings, together with cost factors. The overall infection rate under conventional dressings was 7.1% in 1085 wounds, whereas under occlusive dressings on 3047 wounds the rate was 2.6%. In studies in which the two dressing types were directly compared, the respective rates were 7.6% and 3.2%. The reasons for this difference may include both dressing-specific and host-specific factors, and these factors are discussed.

Wound infection under occlusive dressings.

It is often supposed that occlusive dressings potentiate wound infection. However, even though heavy colonization by skin and wound flora is often seen under certain types of occlusion, clinical infection is not a frequent occurrence. Commensal wound flora consists of a variety of Gram-positive and Gram-negative organisms and fungi which do not appear to be detrimental to healing. Certain aspects of wound healing may in fact be promoted by bacterial colonization, although clinical infection can lead to wound breakdown and systemic infection. Wounds compromised by devitalized tissue, drains or sutures are more susceptible than clean wounds to clinical infection. Occlusive dressings may help prevent infection by presenting a barrier to potential pathogens, and hydrocolloid occlusive dressings have been shown to prevent dissemination of methicillin-resistant Staphylococcus aureus. The rate of clinical infection as deduced from published trials of dressings is lower under occlusion than when non-occlusive dressings are used, and this is likely to be a result of normal activity of the host defences under occlusive dressings.

Microbiology and healing of the occluded skin-graft donor site.

Delayed healing of skin-graft donor sites may be costly and life-threatening, especially in patients with large body surface area burns. A donor site dressing should maximize the ability of the wound to heal without increasing the risk of local infection, systemic infection, or both. Specifically, the possibility of a secondary infection may either slow the healing process or ultimately convert the donor site into a full-thickness skin loss. A number of materials ranging from gauze to biologicals have been investigated for use as donor site dressings. The use of hydrocolloids for donor sites has been widely studied and has shown improved healing rates over the rates reported for conventional dressings. Our recent study using hydrocolloids confirmed earlier research that showed fewer infections and more rapid donor site healing.

Induction of vascularisation by an aqueous extract of the flowers of Calendula officinalis L. the European marigold.

Calendula officinalis L. (calendula) is a plant whose recorded history is indicative of intrinsic wound healing capabilities. The wound healing process involves several distinct phases in which the formation of new blood vessels plays an essential role. This report describes the angiogenic activity of a freeze-dried aqueous extract of the flowers of Calendula officinalis L. (the European marigold) utilizing the chick chorioallantoic membrane (CAM) assay. The CAM assay is a standard and well established method for assessing the angiogenic activity in impure and pure preparations and is suitable for studies requiring examination of large numbers of sample test materials. The angiogenic activity of calendula was measured by examination of CAMs using stereomicroscopy. Further histological investigation and quantification of neovascularization was performed utilizing microvascular counts. The histological sections of CAMs were also examined for the presence of hyaluronan (HA), a tissue glycosaminoglycan associated with neovascularization, by hyaluronidase digestion and staining of tissue sections by alcian blue. All calendula treated CAMs were positive for HA; no HA could be demonstrated in control CAMs. The numbers of microvessels in calendula-treated CAMs were statistically significantly higher than in the control CAMs (p < 0.0001). Thin layer chromatography indicated that the calendula extract contained water-soluble compounds such as flavonoids, but the exact nature of the active angiogenic component(s) has not yet been identified.

Irradiation induces upregulation of CD31 in human endothelial cells.

Radiation-induced vascular injury is believed to be a major factor contributing to parenchymal atrophy, fibrosis and necrosis in normal tissue after radiotherapy. In this study irradiation of human umbilical vein endothelial cells (HUVECs) significantly increased adherence of U-937 cells in a time-dependent manner. Given the potential multifunctional role of CD31 in the vasculature we have examined the possible effects of irradiation on levels of CD31 expression in HUVECs. Irradiation upregulated CD31 expression on HUVECs, independently of initial plating density and radiation-induced changes such as cell number, cell cycle stage, or cell size. CD31 mRNA levels were raised in irradiated HUVECs relative to controls. Both CD31 mRNA and surface protein showed similar changes, suggesting that the increase in mRNA in irradiated HUVECs is responsible for the elevation in cell surface protein. A semi-quantitative study of tissue specimens from patients who had received radiotherapy indicated that CD31 staining in the blood vessels from irradiated tissues was increased compared with controls. Endothelial CD31 is important in the transmigration of leukocytes. We have demonstrated that the incorporation of monoclonal antibody to CD31 significantly inhibited the transmigration of human peripheral blood leukocytes through a monolayer of irradiated HUVECs. Taken together these data strongly suggest that irradiation induces a marked increase in CD31 expression on endothelial cells as part of a general response to irradiation. Its upregulation may play an important role in the development of radiation-induced normal tissue damage and thus is a possible target for therapeutic intervention.

Prospective, multicenter study of managing lower extremity venous ulcers.

Seventy patients with 90 venous ulcers were randomly assigned to hydrocolloid or conventional dressing and compression therapy at four study centers. The ulcers had been present for a mean of 47.8 in the control and 46.2 weeks in the treatment group and 42% of all patients had recurrent ulcers. Ulcers treated with hydrocolloid dressings reduced 71% and control treated wounds reduced 43% in area after 7.2 weeks of treatment. Thirty-four percent of all ulcers healed. Mean time to healing was 7 weeks for the hydrocolloid dressing group and 8 weeks for the control group. Most ulcers were less painful at final evaluation, but reduction in pain was more pronounced in hydrocolloid-dressed ulcers (p = 0.03). At baseline as well as during follow-up, significant differences between study centers were observed. Ulcers in patients in the United Kingdom were larger and less likely to heal (p = 0.001). Size of the ulcer at baseline was associated with treatment response and time to healing (p = 0.002). Percent reduction in ulcer area after 2 weeks was also correlated with treatment outcome (p = 0.004) and time to healing (p = 0.002). When all treatment outcome predictors were analyzed together, only percent reduction in area after 2 weeks remained statistically significant (p = 0.002), with percent reduction during the first 2 weeks of treatment > 30% predicting healing.