Factors that affect equine wound repair.

The rate and outcome of wound healing are determined by many factors,some of which are already in effect when the horse is first presented to the veterinarian. A thorough understanding of wound healing principles,coupled with clear client communication, should enable the practitioner to minimize the number of additional factors that may exacerbate the initial situation.     

Hoof wall wound repair

REASONS FOR PERFORMING STUDY: Surgical stripping of the hoof wall results in a wound that heals remarkabley well. In contrast, lamellae recovering from laminitis are often deformed. Investigating lamellar wound healing may aid understanding of laminitis. OBJECTIVES: To document temporal changes in the lamellar basement membrane (BM), dermis and epidermis after surgery. METHODS: Wall strips were made in the dorsal hoof wall midline of 6 mature horses. Immunohistochemistry was used to document changes in the basement membrane (BM) and detect proliferation of epidermal cells in lamellar tissues harvested at intervals. A conforming metal plate was screwed to the hoof wall to maintain alignment of the wound edges. RESULTS: Wall stripping caused lamellar tips to snap and remain behind in the dermis along with the majority of the lamellar BM and some lamellar basal cells. Three days later the BM was intact and new lamellae had been reconstructed by proliferation of surviving epidermal cells. By 5 days the surface of the stripped zone was covered with yellow epidermis that subsequently thickened and hardened. Eventually the hoof wall deficit was replaced by new wall growing down from the coronet. The conforming metal plate and post operative analgesic ensured minimal lameness. CONCLUSIONS AND POTENTIAL RELEVANCE: In wall stripped lamellae the BM survives virtually intact and is used as a template for proliferating cells, from snapped-off lamellar tips, to migrate and quickly achieve repair to near normality. In laminitis epidermal dysadhesion and lamellar BM destruction occurs and lack of a functional BM template may explain the prolonged and abnormal repair of affected lamellae.     

The pathophysiology of developmental and acute laminitis.

This review implies that although we know more regarding the enigma of developmental and acute laminitis today than previously, there is still more to investigate. As these investigations are conducted and interpreted, new and more effective preventive and therapeutic regimens are likely to be developed, tested, and made available. As this occurs, the impact of laminitis should undoubtedly decrease. Unfortunately, due to the lack of clinical symptoms in the developmental phase and the shortness of the acute phase, it is also evident that the two sequelae of acute laminitis, subacute and chronic laminitis, are likely to continue to pose a major problem for some time.     

The mechanics of wound healing.

This paper discusses the factors which affect the healing of wounds at the tissue and organ levels. It covers some of the problems which complicate the sequence of healing and considers the mechanisms involved in regeneration and repair of tissues. The factors associated with the stimulus and sequence of healing and their interactions are also reviewed.     

The pathophysiology of epilepsy

Recent developments in the understanding of the cellular events in focal seizures are described. This is followed by a discussion of the pathogenesis of neuronal hyperexcitability, the mechanism of spread of the seizure discharge and the mechanisms involved in seizure termination. The pathophysiology of generalized seizures is described in terms of theories of the site of origin of the seizure discharge and possible mechanisms of the clinical phenomena associated with this discharge.     

附红细胞体感染的病理生理和免疫应答力的变化

附红细胞体(Epoerythrozoon spp., 新近被归入霉形体属,称为haemoplasma,即血原体类)感染引起宿主贫血、胆红素血症、低血糖、血液酸中毒和血管内凝血机能变化,也能激起宿主免疫细胞的吞噬活性和特异性体液及细胞免疫应答,但也出现以冷凝集素为标志的自身免疫病。文中阐述了贫血和低血糖等病理生理变化的机理,讨论了免疫应答力变化的原因。     

Suture materials: composition and applications in veternary wound repair

Suture materials play an important role in veterinary surgery by providing support for healing tissues during wound repair. As there is no single ideal suture material, clinicians must compromise on some properties when selecting a material for a specific purpose. By reviewing the characteristics of absorbable and non-absorbable materials, general recommendations can be made on their usage in skin, fascia, viscera and other tissues.     

The pathophysiology of ovine trypanosomosis: haematological and blood biochemical changes.

The course of Trypanosoma congolense infection in sheep was followed for 96 days. Infected animals developed fluctuating parasitaemia, macrocytic normochromic anaemia and leucocytosis which was principally a lymphocytosis. Following treatment with the trypanocidal drug, diminazene aceturate at 84 days after infection, the haematological values returned to normal within 12 days. Infected sheep developed hypocholesterolaemia and hypophospholipidaemia leading to a reduction in total serum lipids. This study has shown that sheep infected with T. congolense develop anaemia, the onset of which follows the first wave of parasitaemia. The changes in blood lipids observed in infected sheep appeared to be related to the intensity and duration of parasitaemia.     

Influence of wound shape on wound contraction in horses.

Three sets of paired circular and square full-thickness skin wounds were made on the dorsum of the metacarpus (n = 48) of 8 horses. Each wound was 6.25 cm2 in area. The wounds were treated topically with an ointment, nonadherent dressing, and bandaged with a snug elastic wrap. Wounds were photographed every other day until healing was complete. Wound areas were measured and exponential and linear wound healing models were applied to the wound healing data generated. Wound healing variables measured for each wound were: number of days to healing, maximal size attained, rate of wound contraction (calculated by use of first-order and linear models), final wound size, and percentage of wound that healed by contraction. The exponential model fit the data significantly better than the linear model. The maximal size attained by circular wounds was significantly smaller than the maximal size attained by square wounds. Wound shape did not influence the rate of wound healing. On the basis of our findings, conversion of circular defects to square defects would not speed wound healing.     

Controlled wound repair in guinea pigs, using antimicrobials that alter fibroplasia

The repair processes of incised wounds depend, in part, on fibroplasia induced by soluble mediators from monocytic macrophages. Two topical antimicrobials were evaluated, each of which effectively controlled wound sepsis and yet each had widely different effects on fibroplasia and wound strength. Paired-incision dermal wounds on the flanks of guinea pigs were treated with a substance containing reactive chlorine (Alcide) or with a compound that is a mixture of two surfactants. One side of each guinea pig was treated with one of the antimicrobials (treated wounds); the opposite side was treated with isotonic saline solution (control wounds). At 7, 10, and 16 days after surgery, tensiometric measurements of C31G (a surfactant)-treated wounds were 99%, 139%, and 195% of control wound values, respectively. Alcide-treated wounds were 76%, 58%, and 88% of control wounds, respectively. Wounds treated with chlorhexidine had reduced strength at 7 days (73%) and at 10 days (78%), but by 14 days, they were similar to control wounds (94%). The main difference between the wounds was the amount of collagen formation. Alcide-treated wounds incorporated less than 50% of the amount of 14C-proline than did the wounds treated with C31G. However, Alcide-treated wounds epithelialized as rapidly as did control wounds, and had minimal scar formation. Microscopic evaluations indicated greatly reduced inflammatory infiltrates in Alcide-treated wounds, indicating that reduced wound strength may be associated with lack of fibroblast-stimulating activity by monocytes.     

Initial wound management.

A wounded patient can be presented to the veterinary surgeon under a number of circumstances. The wound could result from external trauma,such as vehicle trauma or an animal fight, or it could have been created by surgical intervention, such as the removal of a mass. A wound could also be secondary to a failed initial attempt at wound closure. No matter what the cause, initial wound management often follows similar pathways. A successful wound closure and healing outcome is often dependent on adherence to basic principles of wound assessment, appropriate care, and reassessment. This article covers the approach to and specific options for the initial stages of wound management.     

Rabbit wound management.

In conclusion, rabbits have a variety of common disease presentations that require wound management. Anatomic and physiologic characteristics should be kept in mind, as they may have influences upon the management of wounds. Many new topical medications and dressings have been designed that are routinely used in mammalian wound management cases and are potentially useful for rabbits. When topical medications are used in rabbits, care must be taken to ensure the medications are not ingested. In addition to topical therapies, surgical options such as flaps and skin grafts have been researched in rabbits. Many of the wound management concepts that are useful for dogs and cats should be considered when addressing rabbit wounds.     

The use of a caudal auricular axial pattern flap for repair of a degloving pinna wound in a dog

A 3-year-old male neutered French bulldog was presented for an anatomical degloving injury of the left pinna following a conflict with a larger dog at a park. Approximately 2/3 of the dorsal skin was removed from the convex surface of the left pinna along with an irregular, full thickness injury on the lateral aspect of the pinna distal to the cutaneous marginal pouch. A caudal auricular axial pattern flap (CAAPF) was used to reconstruct the pinna. The flap healed with no noted necrosis over the long-term. Postoperative cellulitis was noted for approximately 3 mo. The dog was medically managed for bilateral otitis externa multiple times over the course of recovery. Long-term function and cosmesis at 1.5 y after surgery revealed adequate functional movement of the pinna and acceptable cosmesis. It is concluded that, rather than a pinnectomy, a CAAPF can be offered as a surgical option in dogs that have injuries localized to the pinna.Key clinical message:A CAAPF is an alternative to pinnectomy for reconstruction of the pinna after degloving injury and yields a functional and cosmetically acceptable outcome.     

Chronic axillary wound repair in a cat with omentalisation and omocervical skin flap

A mature, neutered male domestic cat was presented with a chronic axillary wound of unknown origin and at least three years' duration. The diagnostic investigation included screening tests for feline leukaemia virus and feline immunodeficiency virus, tissue culture and histological examination. No underlying aetiology or perpetuating cause could be identified. An omental flap was created, passed via a subcutaneous tunnel, and packed into the wound site after excision of all chronic granulation tissue. The skin defect was closed using an omocervical axial pattern skin flap. A small area of the distal edge of the flap became necrotic but the defect healed by second intention. To the author's knowledge, this is the first clinical report of the use of an omocervical skin flap for repair of a chronic axillary wound in a cat. This flap offers a useful alternative where the use of a thoracodorsal axial pattern flap is not possible due to the extent of the lesion.     

The amino acid taurine--physiology and pathophysiology]

In this review, the main aspects of our knowledge of the physiology and pathophysiology of the beta-amino sulfonic acid taurine will be summarized. After shortly considering the chemistry, the occurrence and the metabolism of taurine, the biological functions of taurine in the mammalian organism will be dealt with. With respect to taurine deficiency, this review will be limited to the cat since taurine is an essential nutrient for this species.     

Principles of early wound management.

The equine practitioner can positively influence wound healing by dispensing appropriate treatment in the first few hours after injury.Positive actions in the early period include hemostasis, meticulous cleansing and debridement of the wound, the use of effective but nonirritating products to disinfect the wound, closure (if indicated)with minimal tension on the suture line, the judicious use of drains,and ensuring adequate tetanus protection. Furthermore, a thorough assessment of the wound and the patient in the initial period after trauma provides pertinent information on prognosis. Finally,good communication and cooperation among all involved parties are necessary to ensure that everyone understands the factors involved and the potential for a successful outcome.     

OB‐cadherin cloning and expression in a model of wound repair in horses

Reason for performing study: Horses suffer from a debilitating impediment in repairing wounds located on the lower limb that leads to the development of a fibroproliferative disorder (exuberant granulation tissue). This condition is a source of wastage since it often forces retirement from competition. Treatments that resolve or prevent this condition are still lacking, maybe due to deficient knowledge of the underlying molecular mechanisms. Fibroblast‐to‐myofibroblast conversion is an essential step allowing contraction during wound repair and is accompanied by an increase in OB‐cadherin expression. Objectives: To clone equine cadherin‐11 (CDH11) cDNA and to study its spatiotemporal expression profile during the repair of body and limb wounds, thereby contributing to a better understanding of the repair process. Methods: Cloning was by a PCR technique. Expression was studied in intact skin and in 1, 2, 3, 4 and 6‐week‐old wounds of the body and limb. Temporal CDH11 gene expression was determined by RT‐PCR while OB‐cadherin protein expression was mapped immunohistochemically. Results: Equine CDH11 is a highly conserved gene and protein. mRNA was not expressed in equine skin whereas the wound repair process was characterised by a significantly higher expression in the thorax than in limb samples. mRNA expression pattern was paralleled by protein data as confirmed by immunohistochemistry. Conclusions: The data suggest that deficient OB‐cadherin expression in the first phases of wound repair contributes to the excessive proliferative response seen in horse limb wounds. Potential relevance: Future studies should verify the quantitative, temporal expression of this protein in order to provide the basis for targeted therapies that might prevent the development of EGT in horse wound repair.