Cerium ions crosslinked sodium alginate-carboxymethyl chitosan spheres with antibacterial activity for wound healing

For wound healing,wound infection caused by bacteria is one of the important reasons that delay wound healing process.Therefore,it is very meaningful to develop a multifunctional wound dressing with antibacterial capability to accelerate wound healing.Sodium alginate(SA) and carboxymethyl chitosan(CMCS) are the most commonly used compositions in wound dressing,but their poor stability inhibits the further applications.Introducing CMCS and using cerium ions(Ce³⁺) to crosslink CMCS and ...     

Retrospective evaluation of postoperative intralesional steroid injections on wound healing

Steroids have been implicated as an etiology in delayed wound healing. Although there is much documentation in the literature that steroids delay wound healing, most studies are in vitro or use high systemic doses. No studies have used a one-time, postoperative, intralesional steroid injection and evaluated wound healing. This study retrospectively reviewed 73 patients with 115 foot and ankle surgeries over 12 years. Seventy-two patients had steroid injections and 43 did not. The average healing time for the steroid group was 17.1 +/- 10.5 days, and for the non-steroid group 17.3 +/- 8.75 days. There were two infections in the non-steroid group, and one infection in the steroid group. There were five dehiscences in each group. The patients were further subdivided into groups based on age, gender, number of procedures, type of surgery, health status, steroid type, and steroid dose. The healing time increased in patients > 60 years old, and in immunocompromised patients. The patients who had more complex surgery had increased healing time. The males had a longer healing time than the females. Overall, there was not a statistically significant difference between the steroid groups and the non-steroid group. Therefore, one-time postoperative intralesional steroid injections were not found to delay wound healing.     

Wound healing microbiology

The relationship between wound healing and cutaneous microbiology is a complex one mediated by the type of wound, its treatment, and the defense mounted by the injured individual. Acute wounds harbor microflora similar to that of noninjured skin. "Dirty" traumatic wounds or chronic wounds with devitalized tissue offer more opportunity for microflora colonization, with the potential for bacterial adherence to the host cells and ultimate invasion into viable tissue or infection. The alterations of these wound environments can be brought on by topical treatments. Occlusive dressings with various moisture vapor transmission rates can provide a wound environment suitable for microflora proliferation. In spite of this increase in numbers of organisms, most wounds do not become infected, as shown by a survey of published trials. Infection requires the proper pathogenic microorganism, its attachment, and subsequent multiplication. To cause an infection, an organism must invade viable tissue and evade the host defense response. The many occlusive dressing types available offer an opportunity to select a wound therapy tailored for the microenvironment most suitable for healing. Wounds can be protected from exogenous microfloral contamination with dressings. Some dressing types, such as hydrocolloid dressings with no moisture vapor transmission, should not be used on chronic wounds suspected of harboring anaerobic organisms. Other typical treatments, such as antiseptics, can injure tissue and make infection more probable, providing devitalized tissue for bacterial adhesion. Povidone-iodine solution has been shown not be efficacious, whereas povidone-iodine cream effectively limits bacteria and infection.(ABSTRACT TRUNCATED AT 250 WORDS)     

The use of air-plasma flows in military field surgery and disaster medicine

Plasma currents of high energy are considered to be very promising in the surgical treatment of modern pathology. The scientists of this country have constructed a portable field surgery apparatus in which a heated atmospheric air assumes a form of a high-temperature thin jet used like a surgeon's scalpel. Experiments and clinical tests proved the efficacy of this microplasmotron that can destroy and coagulate body tissue when treating it with plasma. This new method has, besides hemostatic action, some noticeable antimicrobic effect that leads to acceleration of tissue granulation and wound healing. In specialized and skilled medicare this progressive and priority method should be applied for initial surgical wound treatment, secondary hemorrhage arrests and surgical interventions when a high risk of infection spreading is involved.     

Diabetic periodontitis: possible lipid-induced defect in tissue repair through alteration of macrophage phenotype and function

BACKGROUND: Diabetes mellitus is a major health problem in the United States affecting approximately 13 million people. The five 'classic' complications which have historically been associated with the condition are microangiopathy, neuropathy, nephropathy, microvascular disease, and delayed wound healing. Recently, periodontal disease (PD) has been declared the 'sixth' major complication of diabetes as diabetics demonstrate an increased incidence and severity of PD. The cellular and molecular basis for diabetic PD is unknown. HYPOTHESIS: Recent evidence suggests that PD and delayed dermal wound healing may be manifestations of the same general systemic deficit in diabetes involving impairment of the cellular and molecular signal of wounding via alterations in macrophage phenotype. Diabetes-induced hyperlipidemia may interfere with the normal cellular and molecular signal of wounding by alteration of macrophage function and subsequent dysregulation of cytokines at the wound site. RESULTS: Preliminary data in both animal models and humans suggests that hyperglycemia, in combination with elevations of serum low density lipoproteins and triglycerides, leads to formation of advanced glycation end products (AGEs) which may alter macrophage phenotype. This may be responsible for dysregulation of macrophage cytokine production and increased inflammatory tissue destruction and alveolar bone loss. IMPLICATIONS: Future investigations will consider diabetic PD in the context of a generalized systemic wound healing deficit that manifests as PD in the face of constant pathologic wounding of the gingiva (bacterial plaque) or delayed dermal wound healing in instances of periodic traumatic wounding to other parts of the body. These types of studies will provide information concerning defective tissue repair in diabetics that will have clinical relevance for the understanding of PD and delayed dermal healing as well as applications of appropriate and specific therapies.     

Wound repair in older patients: preventing problems and managing the healing. Interview by Marc E. Weksler

Because advanced age is associated with delayed wound healing and repair, prevention remains the cornerstone of wound care in the older population. Healing is complicated by the increased prevalence in older patients of conditions that predispose them to pressure ulcers, such as malnutrition, immobility, and systemic disease. If preventive measures fail, there are treatments available to minimize surface contact at pressure points and therapeutic agents to promote wound healing. These treatment approaches include topical dressings that create an optimal healing environment, specially designed support surfaces, and growth factor topicals that can increase the proliferation, migration, and protein biosynthesis of cells in the wound bed.     

General principles of wound healing

Wound healing is a complex process involving different biologic and immunologic systems. Despite improvements in diagnostics and therapy, wound failures remain a clinical problem. The approach to a nonhealed wound is an interdisciplinary challenge that should not be underestimated. Better understanding of the complex wound-healing cascade helps our approach to wound healing and its possible failure. Manipulations of the involved immunologic features offer future therapeutic strategies.     

Risperidone in the treatment of schizophrenia: results of a study of patients from Germany, Austria, and Switzerland

Wound healing is a complex series of highly interdependent and overlapping stages involving a number of cellular processes. Macrophages are pivotal to the healing process, as director cells, but also functioning as phagocytes and debridement agents in addition to producing chemoattractants and growth factors which attract cells necessary for repair and control of wound healing processes. A number of other factors influence wound healing, such as oxygen, the immune system, and corticosteroids.     

Fatal systemic mycotic infections in the burned child

Two cases of systemic phycomycotic burn wound infection occurred in severely burned children. Both patients, although treated aggressively, died after systemic colonization through the burn wound by fungi. Modern burn therapy has increased survival of many severely burned children but opportunistic fungal infection remains as an ominous threat. Early recognition, wide excision or amputation, and systemic antifungal agents comprise the current clinical armamentarium against systemic fungal invasion of burn wounds.     

Chronic problem wounds

Chronic problem wounds can result from both local and systemic factors that impair wound healing. The only way to achieve successful closure of these wounds is by an accurate diagnosis based on a thorough history, careful physical examination, optimal wound care, control of systemic and/or local factors, and correction of hypoxia. With a careful, planned management protocol, most wounds eventually heal. Recurrence of some wounds, such as pressure sores and venous stasis ulcers, is a tougher challenge in some patients. Prevention is a very important step in these patients. Efforts are underway that may improve the management of chronic nonhealing wounds.     

Simplified Finite-Element Model for Tissue Regeneration with Angiogenesis

A simplified finite-element model for tissue regeneration is proposed. The model takes into account the sequential steps of angiogenesis (neo-vascularization) and wound closure (the actual healing of a wound). An innovation in the present study is the combination of both partially overlapping processes, yielding novel insights into the process of wound healing, such as geometry related influences, and could be used to investigate the influence of local injection of hormones that stimulate partial processes occurring during wound healing. These insights can be used to improve wound healing treatments. The models consist of nonlinearly coupled diffusion-reaction equations, in which transport of oxygen, growth factors, and epidermal cells and mitosis are taken into account.     

One hundred years of orthopedics in the Netherlands. IX. The treatment of chronic osteomyelitis

Chronic osteomyelitis is characterized by cicatrization of the focus of infection with deteriorating vascularization, which makes the disease increasingly difficult to treat. The treatment in chronic osteomyelitis consists primarily in surgical debridement of the scarified focus of infection; stabilization with external fixation allows better treatment. Following debridement, local antibiotic treatment is possible with gentamicin containing cement beads, if necessary combined with systemic antibiotic treatment. If the infection heals well, a reconstruction may, if necessary, be carried out: bone defects frequently necessitate bone transplantation, bone segment shifting (Ilizarov method) or free muscle flap grafts. In the future, resistant bacteria will make healing harder. There will be more possibility to use resorbable antibiotic vehicles and bone-replacing biomaterials.     

Effect of topical drug vehicles on wound contraction

The effect of vehicles of medical preparations upon wound contraction was tested in animals. The detraction of experimental skin defects on the back of guinea pigs was used which is caused first of all by wound contraction. Wound contraction is more favourably influenced by vaselinum flavum than by pasta zinci mollis and amylum maydis. The influence of pasta zinci mollis was more favourable than the influence of amylum maydis. The comparison of the three unspecific powder constituents lactose, amylum maydis and talcum revealed differences. These investigations do not allow the general recommendation of the use of fatty vehicles in the treatment of ulcers but they do show that such a recommendation can be made when the ulcer is in a region where wound contraction plays an important part in wound healing and when there is no super infection of the ulcer.     

Burn healing in organ cultures of embryonic chicken skin: a model system

Burn wounds cause complex damage to the skin. Unlike simple cuts, burns cause a graded damage at the margin of the wound and leave biochemically complex debris in the wound, two factors that complicate the process of wound healing. To develop an in vitro system for studying cellular responses to burns in whole tissue, we have applied a standardized burn wound to organ cultures of embryonic chicken skin and evaluated cellular changes in response to the burn damage. This simplified system is not subject to uncontrolled infection and does not involve angiogenesis and granulation. Thus, these cultures provide a simplified model of how cells of the dermis and epidermis in and around a burn wound respond to heat damage early in the process of healing.     

Analysis of the tissue movements of embryonic wound healing--DiI studies in the limb bud stage mouse embryo

The tissue movements of epithelial spreading and mesenchymal contraction play key roles in many aspects of embryonic morphogenesis. One way of studying these movements in a controlled manner is to make an excisional skin wound to an embryo and watch the wound heal. In this paper we report our studies of healing of a simple excisional lesion made to the limb bud stage mouse embryo. The wounded, living embryo is cultured in a roller bottle; under such conditions the wound heals with a highly reproducible time course and is completely closed by 24 hr. During the healing period the environment bathing the wound can be simply manipulated by adding drugs or factors to the culture medium. We have used DiI to label mesenchymal cells exposed at the margin of the initial wound and, by following their fate and measuring the area of mesenchyme remaining exposed at various time points during the healing process, we have quantified both the extent of mesenchymal contraction and the extent of reepithelialisation by movement of epidermis over mesenchyme. We show that the two types of tissue movement contribute almost equally (50:50) to the total wound closure rate. We have gone on to investigate the cell machinery underlying these processes. In adult wounds the epidermis migrates by means of lamellipodial crawling, but we show that reepithelialisation in the embryo is achieved instead by purse-string contraction of a cable of filamentous actin which assembles in the basal layer of cells at the free edge of the epidermis. Addition of cytochalasin D to the culture medium blocks formation of this actin cable and leads to failure of reepithelialisation. Contraction of adult wound connective tissue appears to be driven by conversion of dermal fibroblasts into a specialist smooth muscle-like fibroblast, the myofibroblast. However, using an antibody recognising the alpha-isoform of smooth muscle actin and specific for smooth muscle cells and myofibroblasts, we show that a similar conversion into myofibroblasts does not occur at any stage during the embryonic wound healing process. These observations indicate that both of the tissue movements of embryonic wound healing utilise cell machinery fundamentally different from that driving the analogous tissue movements of adult healing.     

Nutrition and the immune system of the gut

Studies suggest that the development and expression of the regional immune system in the gastrointestinal (GI) tract is relatively independent of systemic immunity. This is reflected in significant differences in functional response of T cells and B cells and affects cytokine patterns and activation pathways when regional immunity is compared to systemic immunity. Nutrients have fundamental and regulatory influences on the immune response of the GI tract and, therefore, on host defense. In addition to the effect of nutrition during development, the local impact of different dietary and antigenic elements on the regional immune system contributes to potential diversion of the two systems throughout life. The route of exposure during antigenic contact is known to affect host immune response, whether it be a normal process, happening in the context of normal environmental encounter with nonpathogenic microbes or planned immunization, or occurring as a result of resolution of a potentially pathologic process i.e., an infectious encounter. Interactions at the local level profoundly influence systemic immune response, in part because of intrinsic differences in these systems, and also because of different requirements for optimal function. Although inflammatory processes are central to host defense in the periphery, the protective blocking action of the secretory immunoglobulin A immune response is crucial to local host defense, and, therefore, to the integrity of GI tract immune function. For these reasons, interaction with normal bacteria of the GI tract may be seen as the model of how the system has evolved and provide clues to the restoration of balance in the immunocompromised host. Reduction of normal commensal bacteria in the context of infection or after antibiotic treatment may interfere with nutrient availability and impair beneficial stimulation of GI immune response. This impairment may be associated with continued colonization with opportunistic microbes and inflammatory immune response that could lead to malabsorption and malnutrition. Study of the impact of nutrient imbalance on the function of the GI tract has profound implications for clinical medicine and may in the future lead to the rational design of preventive approaches to support immune response and host defense.     

Lymphocyte function in wound healing and following injury

BACKGROUND: Injury activates a cascade of local and systemic immune responses. METHODS: A literature review was undertaken of lymphocyte function in wound healing and following injury. RESULTS: Lymphocytes are not required for the initiation of wound healing, but an intact cellular immune response is essential for a normal outcome of tissue repair. Injury affects lymphocyte immune mechanisms leading to generalized immunosuppression which, in turn, increases host susceptibility to infection and sepsis. Although the exact origin of post-traumatic immunosuppression remains unknown, stress hormones and immunosuppressive factors, such as inflammatory cytokines, prostaglandin E2 and nitric oxide, affect lymphocyte function adversely. Post-traumatic impairment of T lymphocyte immune function is reflected in decreased lymphocyte numbers, as well as altered T cell phenotype and activity. Antibody-producing B lymphocytes are variably affected by injury, probably secondary to alterations of T lymphocyte function, as a result of their close interaction with helper T cells. Therapeutic modulation of the host immune response may include non-specific and specific interventions to improve overall defence mechanisms. CONCLUSION: Early resuscitation to restore lymphocyte function after injury is important for tissue repair and the prevention of immunosuppression.     

Metalloproteinase inhibitors and wound healing: a novel enhancer of wound strength

BACKGROUND: Wound strength is a balance between collagen synthesis and degradation. The role of collagen breakdown in wound healing is still not well understood. We investigated the role of collagenases (metalloproteinases [MMPs]) in wound healing in using GM6001, a novel inhibitor of MMPs. METHODS: We used the dorsal skin incision model with implantation of polyvinyl alcohol sponges. Twenty male Sprague-Dawley rats were randomly assigned to receive either GM6001 (10 mg/kg body weight) or 2 mL saline subcutaneously. Ten days after operation the animals were killed and fresh wound breaking strength, scar and sponge hydroxyproline content, and collagen type I gene expression in sponges were assayed. In addition, the inflammatory response and the wound fluid cytokine (tumor necrosis factor-alpha [TNF-alpha] and transforming growth factor-beta 1 [TGF-beta 1]) profile were studied. RESULTS: GM6001 significantly increased wound strength (422 +/- 59 vs 302 +/- 33 g, P < .05), whereas scar collagen content did not differ. In the sponge granulomas the inflammatory infiltrate, the collagen content, and the collagen type I gene expression were all significantly decreased by GM6001. CONCLUSIONS: Inhibition of MMP activity during acute wound healing enhances wound strength even though new collagen synthesis and the inflammatory response are significantly decreased. This could be achieved by decreasing collagen turnover or increasing collagen maturation and crosslinking, or both.     

Surgery in patients with HIV infection: indications and outcome

We reviewed the records of 12 patients with HIV infection (one stage I, three stage II, two stage III, six stage IV) who received 15 surgical procedures under general or lumbar/epidural anesthesia. We discussed surgical indications, their poor wound healing and precautions for preventing the risk of transmission of HIV to health care workers. Six emergency and nine elective operations were performed. Postoperative complications developed after three emergency and three elective operations. Ten patients showed delay of wound healing which was not directly correlated with the CD4+ cell count. No operative deaths occurred. In any stage of HIV infection, not only palliative but also curative operations can be performed as long as HIV infection, opportunistic infections and HIV-related neoplasms can be controlled. Late stage wound healing is poor, but the wound will heal without keloid formation, although it takes two to three times longer than usual. For operating on patients with HIV infection precautions for preventing needle sticks, sharp injuries and blood exposure should be learned and used by health care workers. As a result, surgical staff members will be able to perform operations safely on HIV-infected patients to improve both quality of life and the prognosis of their disease.     

Postoperative pneumonia

Thoracic surgical patients are susceptible to pneumonia because of impaired systemic and lung host defenses. The incidence of pneumonia is higher with more extensive lung resections. Current prophylactic antibiotic therapy is based primarily on general surgical experience with emphasis on wound infection, not pneumonia. With expansion of indications for lung resection to include higher risk patients, there is a need to render antibiotic prophylaxis more specific to bacteria causative of pneumonia.