Safety and effect of transforming growth factor-β2 for treatment of venous stasis ulcers

Transforming growth factor-beta(2) promotes healing in a variety of animal models and exhibits clinical effects thought to be mediated by connective tissue formation. Two clinical trials were conducted to evaluate the safety and effect of transforming growth factor-beta(2) purified from bovine bone and delivered topically to venous stasis ulcers three times per week for up to 6 weeks by means of a lyophilized collagen vehicle. The first was an open-label trial comparing transforming growth factor-beta(2) purified from bovine bone (0.5 microg/cm(2)) with a placebo consisting of lyophilized collagen vehicle-without active drug. After no safety issues arose in that trial, a prospectively randomized, closed-label, observer-blinded, three-armed trial was conducted to compare bovine transforming growth factor-beta(2) (2.5 microg/cm(2)) with the collagen matrix placebo vehicle and with a standard dressing. Standardized elastic compression was applied to all test extremities. The rate of reduction of ulcer area as measured by planimetry was the primary measure of effect. No serious safety-related events occurred in either trial. Clinical evaluation suggested that improvement in the quality and quantity of granulation tissue appeared to precede epithelialization of ulcers treated with bovine transforming growth factor-beta(2). In both studies, treatment with bovine transforming growth factor-beta(2) appeared to have a positive effect on the rate of ulcer closure, whereas ulcers in the control groups continued to exhibit impaired healing. In the open-label study, the mean rate of closure of ulcers treated with bovine transforming growth factor-beta(2) was significantly greater than that of ulcers treated with placebo. There was likewise enhanced reduction in ulcer area in the ulcers treated with bovine transforming growth factor-beta(2) in the second trial. However, because of a higher variability in patient response and a greater placebo effect, the difference was not significant. The placebo was not worse than the standard care arm, thereby showing that the vehicle is not injurious to healing. The combined results of the two trials suggest that, at doses of 0.5 to 2.5 microg/cm(2), bovine transforming growth factor-beta(2) is safe as a topically applied agent in a collagen matrix vehicle and can have a positive effect on closure of venous stasis ulcers. Large multicenter trials appear to be indicated to evaluate fully the potential utility of transforming growth factor-beta(2) in accelerating closure of chronic dermal ulcers.     

Update on the Interaction of Rifampin and Warfarin

A 79-year-old man with a history of deep vein thrombosis and pulmonary embolism received anticoagulation therapy with warfarin 5 mg daily for 8 months. He was diagnosed with osteomyelitis and underwent partial metatarsal resection of his right foot. After surgery, antibiotics were initiated including ertapenem sodium 1 g intravenously every 24 hours, vancomycin 1400 mg intravenously every 24 hours, and rifampin 300 mg by mouth twice daily. Achieving a therapeutic level of anticoagulation was difficult despite escalating doses of warfarin, because of the interaction with rifampin. A 5- to 6-fold increase in warfarin dose was prescribed to reach therapeutic international normalized ratios (INRs), but even these increases were insufficient to maintain his INR in the therapeutic range. After rifampin was discontinued, warfarin doses were gradually reduced over the next 2 months. When concurrent warfarin-rifampin therapy is necessary, vigilant monitoring is imperative and significant increases in warfarin doses are likely.     

Prospective Open-Label Study of Botulinum Toxin Type A in Patients with Axillary Hyperhidrosis: Effects on Functional Impairment and Quality of Life

BACKGROUND: Patients with primary axillary hyperhidrosis experience substantial functional impairment and reduced health-related quality of life (HRQOL). Few studies have comprehensively evaluated the effects of botulinum toxin type A (BoNT-A) on these symptoms. OBJECTIVE: To prospectively assess the effects of BoNT-A on functional impairment associated with primary axillary hyperhidrosis. METHODS: Patients treated with BoNT-A 50 U per axilla at baseline were assessed 4 and 12 weeks later. Outcome measures included functional impairment as assessed by the Hyperhidrosis Disease Severity Scale and the Hyperhidrosis Impact Questionnaire and dermatology-specific HRQOL as assessed by the Dermatology Life Quality Index. RESULTS: At weeks 4 and 12 after BoNT-A treatment, 85% and 90% of patients achieved the a priori definition of treatment responder. Patients reported less occupational and emotional impairment, spent less time managing their hyperhidrosis, and had fewer difficulties in social situations. Adverse events were uncommon (5.5%), were mild, and did not require treatment. At study end, 53% of patients reported no dermatology-specific HRQOL impairment and 90% were satisfied with treatment. CONCLUSIONS: Significant, meaningful, rapid, and durable reductions in disease severity and functional impairment, as well as improvements in HRQOL, were seen following BoNT-A treatment. BoNT-A was safe and well tolerated, producing high levels of patient satisfaction.     

Optimization and validation of an ischemic wound model

Localized tissue ischemia is a key factor in the development and poor prognosis of chronic wounds. Currently, there are no standardized animal models that provide sufficient tissue to evaluate the effect of modalities that may induce angiogenesis, and in vitro models of angiogenesis do not mimic the complexity of the ischemic wound bed. Therefore, we set out to develop a reproducible ischemic model for use in wound-healing studies. Male Sprague-Dawley rats underwent creation of dorsal bipedicle skin flaps with centrally located excisional wounds. Oxygen tension, wound-breaking strength, wound area, lactate, and wound vascular endothelial growth factor (VEGF) were compared in flaps measuring 2.5 and 2.0 x 11 cm with and without an underlying silicone sheet. We found that the center of the 2.0 cm flap with silicone remains in the critically ischemic range up to 14 days without tissue necrosis (33+/-4 vs. 49+/-6 mmHg in controls). Wound healing and breaking strength were significantly impaired and tissue lactate from the center of this flap was 2.9 times greater than tissue from either nonischemic controls and 2.5 cm flap (0.23+/-0.05 mg/dL/mg sample vs. 0.09+/-0.02 and 0.08+/-0.02, respectively). Vascular endothelial growth factor was 2 times greater than the nonischemic control. This ischemic wound model is relatively inexpensive, easy to perform, reproducible, and reliable. The excisional wounds provide sufficient tissue for biochemical and histologic analysis, and are amenable to the evaluation of topical and systemic therapies that may induce angiogenesis or improve wound healing.     

The Environmental Context of Patient Safety and Medical Errors

The environmental context of patient safety and medical errors was explored with specific interest in rural settings. Special attention was paid to unique features of rural: healthcare organizations and their environment that relate to the patient safety issue and medical errors (including the distribution of patients, types of adverse events associated with learning, information flows, triage and transfer decisions, and culture of safety). Relevant organizational theories and strategies fo medical error reduction and prevention in rural health care settings were identified. Financial and technical assistance are needed to support the systematic collection of data from rural hospitals and other entities and to enhance relevant patient safety practices for rural America.     

Subgroups of smokers with different success rates after use of transdermal nicotine

To identify subgroups of smokers with different success rates, we applied "tree-structured survival analysis" (TSSA) to data from a previously published trial of transdermal nicotine. The subjects who received active treatment (14 mg patch, n 275, or the 21 mg patch, n 262) constituted the sample for this analysis. Using age, gender, the Fagerstrom Tolerance Questionnaire (FTQ), motivation to quit, number of cigarettes smoked at baseline, and body mass index (BMI) as classification variables, TSSA identified two subgroups within the 14 mg patch group and four subgroups of smokers within the 21 mg patch group. Among those receiving the 14 mg patch, individuals with a BMI greater than 26.4 kg/m relapsed sooner than did those with a BMI less than or equal to this value. Within the 21 mg patch group, the survival curve for males was significantly different from that observed in females, with males experiencing a longer time to relapse after treatment than did females. Among males, those who were less dependent relapsed significantly later than did those men who were more dependent. Among females, those with a higher motivation to quit relapsed more slowly than did those women with less motivation to quit. This information may be helpful to clinicians seeking to match specific patients to specific treatments with transdermal nicotine in order to maximize treatment outcomes.     

Viral Persistence in Neurons Alters Synaptic Plasticity and Cognitive Functions without Destruction of Brain Cells

Neurons have a restricted expression of MHC heavy chain molecules which prevents presentation of antigens of infecting viruses. As a result, such infected cells escape immune surveillance and allow the establishment of noncytolytic persistent infection. Here we show that a chronic noncytolytic viral infection bothin vitroandin vivoselectively perturbed the expression of GAP-43, a protein that plays a central role in neuronal plasticity processes accompanying learning and memory. GAP-43 expression was greatly decreased in the hippocampus, an area of heightened viral replication, while synaptic density was preserved. Concurrently, the ability to learn tasks was significantly impaired in these persistently infected mice. Yet, infected neurons remained free from structural injury.