Changes in the lipid peroxidation activity and intensity of tissue respiration during healing of aseptic and infected wounds in animal experiments

The variance of lipid peroxidation (LPO) was studied by the concentrations of malonic dialdehyde (MDA) in the tissue of wound bed and blood serum on the model of surface musculocutaneous aseptic and infected wounds simulated in 250 rats. The speed of oxygen consumption by isolated wound tissue was determined simultaneously. It was stated that the time course of MDA concentration in wounds and sera as well as tissue respiration in animals with infected wounds differed from those in animals with aseptic wounds. In a whole, MDA levels were found to be higher in cases with infected wounds and of changeable character. The latter animals demonstrated less intensive respiration of granulation tissue. Correlation between the variance of tissue respiration and MDA levels was established as was that of LPO and respiration with the phases of wound process. The findings could be used for the development of pathogenetic therapy and evaluation of its efficacy.     

Enriched collagen as coadjuvant therapeutic agent in experimental osteomyelitis in dogs

Osteomyelitis was induced in the tibiae of dogs by injecting hemolytic strain of Staphylococcus aureus. Clinical, radiological and histomorphological reactions in the diseased tibiae were studied up to 15 weeks to evaluate the response of infected bone to parenteral oxytetracycline in cases of closed wounds and surgical curettage, antimicrobial irrigation along with parenteral oxytetracycline therapy in animals carrying open wounds. Enriched collagen as a constituent of therapeutic regimen was also administered locally and its efficacy during resolution of osteomyelitis was compared with other treatments. Surgical curettage along with irrigation of lesions was observed to be an effective method for bringing an early recovery in aggravated cases of osteomyelitis. The addition of collagen enhanced the healing process in comparison with non-collagen treated animals.     

Relationship between mechanical properties and collagen structure of closed and open wounds

Mechanical properties and collagen structure of excisional wounds left open are compared with wounds closed by clips. In both wound models, collagen fiber diameter increases with time post-wounding and is related to tensile strength. Clipped wounds show a higher ultimate tensile strength and tangent modulus compared with open wounds. In clipped wounds, newly deposited collagen appears as a biaxially oriented network as observed in normal skin. In open wounds a delay in the organization of the collagen network is observed and parallel wavy-shaped ribbons of collagen fibers are deposited. At long term, the high extensibility observed in open wounds may be due to the sliding of ribbons of collagen fibers past each other.     

Evaluation of Lyophilised, Gamma-Irradiated Amnion as a Biological Dressing

Burns, non-healing wounds and pressure sores cause extensive damage to the skin leading to infection and loss of precious body fluids. Despite advances in burn management the mortality rate continues to be high and the search for an economical and easily available dressing to control burn wound infection continues. Autologous skin has limited availability and is associated with additional scarring. Conventional dressings require frequent changes which can be painful and may even require anaesthesia.Amnion is an excellent biological dressing and its use in the treatment of burns has special appeal in India as there are religious barriers to the acceptance of bovine and porcine skin.Lyophilised, irradiated amnion provided for the first time in the country by the Tata Memorial Hospital Tissue Bank was evaluated as a temporary biological dressing. It was used to treat 35 patients with burns, 21 patients with bedsores and non-healing ulcers and the skin graft donor sites of 11 patients.The amnion was easy to handle and stuck well to the raw wound bed. An open dressing was used in most of the second degree burns which healed with hyperemia and early pigmentation. In patients with third degree burns, ulcers or skin graft donor sites, closed dressings were used. The exudate and induration were reduced and patients were more comfortable and experienced less pain. There was healthy granulation with good re-epithelialisation. Amnion was not used in patients with infected third degree burns.     

Expanding the horizons in treatment of severe peripheral vascular disease using microsurgical techniques

The use of microvascular tissue transfer as an adjunct to arterial reconstruction has begun to have a positive impact on limb salvage in patients with advanced arteriosclerosis and nonhealing ischemic wounds. However, many patients with severe peripheral vascular insufficiency not amenable to conventional arterial reconstructive procedures eventually require limb amputation. We have treated 12 patients with advanced peripheral vascular disease and nonhealing ischemic wounds by three different methods. These included distal bypass alone, distal bypass done in conjunction with free-tissue transfer, and free-tissue transfer alone. All bypass grafts were done to vessels at or below the ankle using a reversed saphenous vein. In each case, the distal anastomosis was performed, using the operating microscope and standard microvascular technique. Mean follow-up for these patients is 18 months. Distal bypass alone resulted in limb salvage in three of five patients. In the combined bypass and free-flap group, three of five patients had salvage of their threatened extremity at a 1-year follow-up. Two patients with ischemic ulcers, rest pain, and unsuitable distal vessels for bypass were treated with free-tissue transfer alone. This resulted in healed wounds, limb salvage, and complete resolution of the rest pain symptoms in both patients. When advanced ischemia is complicated by large areas of tissue loss, combined bypass and microvascular free-issue transfer, performed in stages or simultaneously, is safe and can often result in limb salvage. In the rare instance of a completely obliterated distal runoff bed, free-tissue transfer alone may provide not only a healed wound, but also a means of "indirect" revascularization of the extremity and limb salvage.     

An experimental study on the natural removal of dead trout fry in a Lake District stream

The chief objective was to discover why few moribund or dead Salmo trutta fry were observed on the stream bed when mortality within the stream was known to be high ( c . 13 000 dead fry year ⁻¹ for whole stream). Newly dead fry were placed in 20 boxes embedded in the stream bed (20 fry of known total weight per box) and arranged in pairs with one box open and one closed. One pair was removed every 2 days, the fish remains being weighed and the invertebrates in the open box being identified and counted. The experiments were performed from late April to early May in 1967, 1968, 1969 and the results were similar in each year. Both wet and dry weights of fry decreased exponentially but the rate of decrease was much higher in the open boxes; detectable fish remains were about 55% of initial weights after 20 days (end of experiment) in closed boxes but zero after 16 days in open boxes. Invertebrate scavengers were responsible for the higher loss rates in the open boxes and showed a definite succession with caddis larvae and carnivorous stonefly larvae dominant at first, but then being replaced by detritivorous stonefly larvae and freshwater shrimps. These experiments show clearly why dead fry disappear rapidly from the stream bed.     

The use of vacuum-assisted closure therapy for the treatment of lower-extremity wounds with exposed bone

Lower-extremity wounds with exposed tendon, bone, or orthopedic hardware present a difficult treatment challenge. In this series of patients, subatmospheric pressure therapy was applied to such lower-extremity wounds. Seventy-five patients with lower-extremity wounds, most of which were the result of trauma, were selected for this study. Dressings made of sterile open-cell foam with embedded fenestrated tubing were contoured to the wound size and placed into the wound. The site was covered with an adhesive plastic sheet. The sheet was placed beneath any external fixation devices, or the fixation device was enclosed within the sheet. The tubing was connected to the vacuum-assisted closure pump. Continuous subatmospheric suction pressure (125 mmHg) was applied to the wound site. The wounds were inspected and the dressings were changed every 48 hours.Vacuum-assisted closure therapy greatly reduced the amount of tissue edema, diminishing the circumference of the extremity and thus decreasing the surface area of the wound. Profuse granulation tissue formed rapidly, covering bone and hardware. The wounds were closed primarily and covered with split-thickness skin grafts, or a regional flap was rotated into the granulating bed to fill the defect. Successful coverage was obtained without complication in 71 of 75 patients. Wounds have been stable from 6 months up to 6 years.     

Effect of sodium diphenylhydantoin on skin wound healing in rats

This study evaluated the effect of phenytoin (sodium diphenylhydantoin) on skin wound healing in a rat model. The study was divided into two parts. In part I, 20 mul of phenytoin (10 mg/ml) was subcutaneously injected into the 3-cm dorsal full-thickness incisional wounds of 14 rats on postoperative days 0, 3, and 6. Twelve rats that received saline injections were used as the controls. The skin samples were harvested and tested for tensile strength and histology. An additional 12 rats with the same incisional wounds were tested for chemokine gene expressions. In part II, 20 mul of phenytoin (10 mg/ml) was applied topically once a day on a 4 x 4 cm area of the open dorsal wounds of 10 rats. Saline was applied to the wounds of the 10 control group rats. The wounds were measured weekly. The results showed that the average tensile strength of the phenytoin-treated wound was 0.49 +/- 0.08 MPa compared with the control group at 0.02 +/- 0.01 MPa (p < 0.05). The density ratio of chemokine monocyte chemotactic protein (MCP-1) to beta-actin in the phenytoin-treated group was also significantly higher than in the control group (p < 0.05). Histologic analysis of the phenytoin group showed a large amount of fibroblast proliferation, collagen synthesis, and neovascularization. Phenytoin-treated wounds were also smaller at 1 to 6 weeks postoperatively than the control group wounds. The authors conclude that the administration of phenytoin can promote wound healing and significantly increase MCP-1 expression. Phenytoin-treated wounds showed significant increase in collagen deposition and neovascularization, which resulted in an increased wound tensile strength and accelerated healing of both open and closed wounds.     

Limb salvage of lower-extremity wounds using free gracilis muscle reconstruction

An extensive series reviewing the benefits and drawbacks of use of the gracilis muscle in lower-extremity trauma has not previously been collected. In this series of 50 patients, the use of microvascular free transfer of the gracilis muscle for lower-extremity salvage in acute traumatic wounds and posttraumatic chronic wounds is reviewed. In addition, the wound size, injury patterns, problems, and results unique to the use of the gracilis as a donor muscle for lower-extremity reconstruction are identified. In a 7-year period from 1991 to 1998, 50 patients underwent lower-extremity reconstruction using microvascular free gracilis transfer at the University of Maryland Shock Trauma Center, Johns Hopkins Hospital, and Johns Hopkins Bayview Medical Center. There were 22 patients who underwent reconstruction for coverage of acute lower-extremity traumatic soft-tissue defects associated with open fractures. The majority of patients were victims of high-energy injuries with 91 percent involving motor vehicle or motorcycle accidents, gunshot wounds, or pedestrians struck by vehicles. Ninety-one percent of the injuries were Gustilo type IIIb tibial fractures and 9 percent were Gustilo type IIIc. The mean soft-tissue defect size was 92.2 cm2. Successful limb salvage was achieved in 95 percent of patients. Twenty-eight patients with previous Gustilo type IIIb tibia-fibula fractures presented with posttraumatic chronic wounds characterized by osteomyelitis or deep soft-tissue infection. Successful free-tissue transfer was accomplished in 26 of 28 patients (93 percent). All but one of the patients in this group who underwent successful limb salvage (26 of 27, or 96 percent) are now free of infection. Use of the gracilis muscle as a free-tissue transfer has been shown to be a reliable and predictable tool in lower-extremity reconstruction, with a flap success and limb salvage rate comparable to those in other large studies.     

Vanadate ingestion increases the gain in wound breaking strength and leads to better organized collagen fibers in rats during healing

Repair of incision wounds closed by suturing is evaluated by the progressive gain in wound breaking strength. Previously the closure of open wounds in rats ingesting vanadate, an inhibitor of tyrosine phosphate phosphatases, was shown to occur with deposition of more uniformly organized collagen fiber bundles. The hypothesis of this study was that deposition of more uniformly organized collagen fibers would enhance the gain in wound breaking strength of incisional wounds. Six adult rats received vanadate-supplemented saline drinking water for 1 week before placement of two 6-cm, parallel, suture-closed wounds on their backs. Six control rats received identical wounds and were given saline drinking water. The drinking water regimen was continued for 1 week after wounding, and then wound strength was tested with a tensiometer and tissue samples were obtained for histologic evaluation. Wound breaking strength doubled in vanadate-treated rats compared with controls. Bright-field and polarized light microscopy showed that the connective tissue matrix of granulation tissue from control rats was oriented perpendicular to the surface of the skin. In contrast, the connective tissue matrix of granulation tissue from vanadate-treated rats was oriented parallel to the skin surface. The gap in granulation tissue between the edges of the wounds in the vanadate-treated rats was greater than that in controls. Electron microscopy showed that wounds in the vanadate-treated contained uniform collagen fibers that were 20 percent greater in diameter and more evenly spaced than they were in controls. It is proposed that these changes in the organization of collagen fibers within incisional wounds were responsible for the increased wound breaking strength observed in rats ingesting vanadate.     

Reaching the canopy on the ground: incidence of infection and host-use by mistletoes (Loranthaceae and Viscaceae) on trees felled for timber in Amazonian rainforests

There is a profound absence of knowledge of infestation prevalence and host-use by mistletoes of mature South American tropical rainforests. In this study, we fill this gap using information gathered from felled trees at a logging concession area in Amazonian Brazil. We sampled individuals of 18 tree species, which occurred in two forest physiognomies; open forest with canopy interrupted by palm trees and closed, denser forest, with emergent trees. We hypothesized that infection incidence would be higher in open than in closed forest, irrespective of the mistletoe species involved. In addition, we expected that mistletoe parasitism would be higher on host species that were more abundant, taller, deciduous, and had less dense wood. We sampled 870 individual trees in both sites combined. All but one host species was infected by at least one species of mistletoe. We found 13 mistletoe species/morphospecies, Loranthaceae (7) and Viscaceae (6), parasitizing very different hosts. Mistletoe infection incidence was higher in the closed forest (10.3%) than in the open forest (5.4%). In the closed forest, host height influenced incidence positively, while deciduousness had a negative influence. Our results show that mistletoes are common in the canopy of pristine tropical forests and, contrary to expectations, that infection incidence was higher in the closed forest. The positive relation between infection incidence and host height in this forest type suggests that emergent trees have higher chances of being infected than individuals of correspondent species in the lower forest layers.     

Validation of a model for the study of multiple wounds in the diabetic mouse (db/db)

The genetically diabetic db/db mouse exhibits symptoms that resemble human type 2 diabetes mellitus, demonstrates delayed wound healing, and has been used extensively as a model to study the role of therapeutic topical reagents in wound healing. The purpose of the authors' study was to validate an excisional wound model using a 6-mm biopsy punch to create four full-thickness dorsal wounds on a single db/db mouse. Factors considered in developing the db/db wound model include reproducibility of size and shape of wounds, the effect of semiocclusive dressings, comparison with littermate controls (db/-), clinical versus histologic evidence of wound closure, and cross-contamination of wounds with topically applied reagents. The size of wounds was larger, with less variation in the db/db mice (31.11 +/- 3.76 mm2) versus db/- mice (23.64 +/- 4.78 mm2). Wounds on db/db mice that were covered with a semiocclusive dressing healed significantly more slowly (mean, 27.75 days) than wounds not covered with the dressing (mean, 13 days; p < 0.001), suggesting the dressings may splint the wounds open. As expected, wounds healed more slowly on db/db mice than db/- mice (covered wounds, 27.75 days versus 11.86 days, p < 0.001; wounds not covered, 13 days versus 11.75 days, p = 0.39). Covered wounds, thought to be closed by clinical examination, were confirmed closed by histology only 62 percent of the time in the db/db and 100 percent of the time in the db/- mice. Topical application of blue histologic dye or soluble biotinylated laminin 5 to one of the four wounds did not spread locally and contaminate adjacent wounds. Multiple, uniform, 6-mm wounds in db/db mice heal in a relatively short time, decrease the number of animals needed for each study, and allow each animal to serve as its own control. The db/db diabetic mouse appears to be an excellent model of delayed wound healing, particularly for studying factors related to epithelial migration.     

Free tissue coverage of chronic traumatic wounds of the lower leg

Thirty-eight consecutive patients who underwent 42 free flaps for chronic wounds of the lower leg were identified over an 11-year period. All wounds were open for a minimum of 1 month (mean, 40 months; median, 8 months; range, 1 month to 30 years). The average age was 37 years (range, 7 to 68 years), there were 31 male patients and seven female patients, and the average follow-up time was 30 months (range, 12 to 72 months). The original injury was an open fracture in 28 patients, wound dehiscence after open reduction and internal fixation of a closed fracture in nine patients, and a shrapnel wound in one patient. A total of 23 patients had osteomyelitis, which was classified as local (involving less than 50 percent of the bone diameter) in 15 patients and as diffuse (involving greater than 50 percent of the bone diameter or infected nonunion) in eight patients. The wounds were treated with sequential debridement, antibiotics, and flap coverage. Ancillary procedures included antibiotic beads in 18 patients, saucerization in 16, Ilizarov bone transport in three, calcanectomy in two, and fibular resection and ankle fusion in one. Thirty-four of 42 flaps survived, four having undergone a repeat free flap. There were three failures out of 25 flaps (12 percent) among those with a normal angiogram and five failures out of 15 flaps (33 percent) among those with an abnormal angiogram (p > 0.05). The failure rate of those with osteomyelitis was six of 26 (23 percent) versus two of 26 (13 percent) for those without osteomyelitis (p > 0.05). Successful reconstruction (bone healed, patient ambulatory and infection-free) was achieved in 33 of 38 patients (87 percent). The failure of reconstruction for those patients with osteomyelitis was four of 23 (22 percent) versus one of 15 (7 percent) for others (p > 0.05). The failure rate of flaps in patients with diffuse osteomyelitis was three of eight (38 percent) versus two of 30 for others (7 percent, p = 0.053). The presence of diffuse osteomyelitis was associated with a lower rate of successful limb reconstruction. An abnormal angiogram and the presence of osteomyelitis both were associated with a lower rate of successful limb reconstruction, but this was not significant, probably because of the small size of the cohort.     

Different products for biological control of Botrytis cinerea examined on wounded stem tissue of tomato plants

For the moment the agents that are used against Botrytis cinerea, in glasshouses were tomatoes are cultivated, are from chemical origin. For reducing the use of chemical agents in the future it is important to search for effective biological control agents against the fight of Botrytis cinerae. The following biological products Vital pasta, Vital gel and Elot-Vis were examined in there possibility to control Botrytis cinerea. Elot Vis was tested out in experiments that were carried out in climate chambers were leafs of 3 week old tomato plants were artificially infected with Botrytis cinerea spores. Also the biological products of Vital were first investigated in experiments that were carried out in climate chambers. In stead off leafs of tomato plants it were stem wounds of tomato plants who were treated with the pasta or the gel that was spread over the wounded surface after this has been inoculated with a suspension of conidia of Botrytis cinerae. The results of these first tests that were executed in the climate chambers were the circumstances for Botrytis cinerea were ideal seemed promising. In the next step these products were tested out on large scale in glasshouses. For each plant 5 wounds were created by removing the leafs, these wounds were or first treated with the Biological product and thereafter artificially infected with Botrytis cinerea spores to check out if these products can be used as a preventive agent or the wounds were first inoculated with a suspension of Botrytis cinerea spores and thereafter treated with the product. For the product Elot-Vis a few plants were totally sprayed with an Elot-Vis suspension before leafs were removed and the wounds were inoculated with conidia of Botrytis cinerea to check out if this product was able to activated the induced systemic resistance pathway. The experiments that were executed in glasshouses showed different percentages of succeeded Botrytis cinerea infections. This is probable due to the different weather conditions during both days that the experiments were executed. For the wounds that were treated with pasta it was difficult to distinguish wounds were Botrytis cinerea succeeded to infect the plant, because these wounds frequently didn't show any sign of infection on the surface but when the wounds with the pasta were cut open it was possible to see Botrytis cinerea infections inside the stem.     

Estimation of age-related changes in the regulation of peripheral blood flow in humans

The age-dependent features in the state of skin microvascular bed has been studied with laser Doppler flowmetry in healthy volunteers of different age groups. To reveal the reaction of skin blood flow in response to short-term ischemia, the occlusive test has been carried out. To estimate the contribution of rhythmic components to blood flow signal, continuous wavelet-transform spectral analysis was used. Age-dependent increase of pulse-wave amplitude and decrease of respiratory wave amplitude reflecting age-dependent changes in functioning of arteriolar and venular links of microvascular bed have been observed at rest. In response to short-term ischemia the age-dependent reduction of reserve resources has been revealed in functioning of arteriolar link of microvascular bed. The reduction of activity of myogenic, neurogenic and endothelial regulation systems have been shown at rest in ageing.     

The effect of fibrin glue on skin grafts in infected sites.

Fibrin bonding of skin grafts to wounds is an essential part of the graft-adherence process. Bacteria, in concentrations greater than 10(5)/gm of tissue, are associated with graft failure. Sixty-five rats were randomly divided into three groups, dorsal split-thickness skin grafts were harvested, and the sites were inoculated with Staphylococcus aureus. After incubation, each wound was quantitatively biopsied and treated with saline, fibrin glue with aprotinin, or fibrin glue alone. We found that the addition of commercially available fibrin glue with or without the antifibrinolytic agent aprotinin is capable of restoring graft adherence to normal levels in graft sites infected with greater than 10(5) bacteria/gm of tissue. Fibrin glue may have potential for increasing skin-graft take in the clinical situation where the graft bed is infected.     

Effects of thermal factors on the state of microcirculation of the small intestine in acute ischemia

The influence of normo- (38 degrees C), hyper- (42 degrees C) and hypothermia (20 degrees C) on microcirculatory disturbances caused by acute local ischemia of the small intestine was investigated with the help of biomicroscopy as well as morphological methods. Ischemia was modeled by ligation of the intestine look eventrated through the abdominal wall incision of a rat onto the microscope stage for 1 h. It was shown that hyperthermia intensified microcirculatory disorders and stimulated destructive processes in tissues and hypothermia promoting microcirculation and decreasing metabolism and restrained the development of these processes. Important peculiarity of the microvascular response to ischemia, hyper- and hypothermia was revealed: heterogeneity of the reaction of different parts of microvascular bed. Appropriate evaluation of the microcirculation state in such conditions can be obtained taking into account not only the qualitative character of microvascular reaction but also an extent of this reaction manifestation in different parts of microvascular bed.     

Effects of 20 days horizontal bed rest on maintaining upright standing posture in young persons

The effects of 20 days horizontal bed rest (BR) on postural reflex were studied by measuring fluctuation of center of gravity in the body during two legs or one leg upright standing in 10 young volunteers. The fluctuation was decided as total moving distance of the center recorded during 60sec standing on a force plate. The stability was measured by the moved area. After BR, the moving distance increased during two legs standing with open eyes (p<0.05), but statistically unchanged with closed eyes. The moving area decreased during right one-leg standing with closed eyes (p<0.05), but unchanged during left one-leg standing. Despite with open eyes the increased distance suggested that postural reflexes to maintain upright position were probably decreased by increased unsuitable feedback informations from the visual receptor deconditioning during BR. The decreased area during right one-leg standing with closed eyes also suggested that the declined standing posture reflex was probably related to more rapidly lowered functions for maintaining standing position in the dominating leg than in the other.     

Clinical trials of amniotic membranes in burn wound care

Four test conditions of increasing complexity were used to evaluate the clinical efficacy of amniotic membranes as biologic dressings on donor sites and burn wounds in children. These were the clean-skin donor-site wound, the uncontaminated shallow partial-thickness burn wound, the bed of freshly excised full-thickness wounds, and the granulating surface of colonized burn wounds. The rate of epithelialization under amniotic membranes was the same as that under 5% scarlet red ointment or 0.5% silver nitrate solution dressings. Preservation of a healthy excised wound bed and maintenance of a low bacterial count in contaminated wounds paralleled the experience with human allograft dressings despite technical difficulties and the absence of vascularization of amniotic membrane and its fragile structure. Tentative conclusions are drawn as to the mechanisms by which biologic dressings exert their beneficial effects.     

Characteristics of the microcirculation and blood rheology in arterial and venous forms of mesenteric vascular occlusion

The functional properties of microcirculation and rheology of blood were studied in dogs subjected to arterial and venous occlusion of mesenteric vessels (cranial mesenteric artery and cranial mesenteric vein). It was found that a local alterations of microvascular bed of intestinal wall are quite different in case of arterial or venous occlusion. The degree of hemorheological and microvascular deviations is higher in case of acute venous thrombosis than during the acute occlusion of cranial mesenteric artery.