How does atmospheric pressure cold helium plasma affect the biomechanical behaviour on alkali-lesioned corneas?

BACKGROUND

Melting corneal ulcers are a serious condition that affects a great number of animals and people around the world and it is characterised by a progressive weakening of the tissue leading to possible severe ophthalmic complications, such as visual impairment or blindness. This disease is routinely treated with medical therapy and keratoplasty, and recently also with alternative regenerative therapies, such as cross-linking, amniotic membrane transplant, and laser. Plasma medicine is another recent example of regenerative treatment that showed promising results in reducing the microbial load of corneal tissue together with maintaining its cellular vitality. Since the effect of helium plasma application on corneal mechanical viscoelasticity has not yet been investigated, the aim of this study is first to evaluate it on ex vivo porcine corneas for different exposition times and then to compare the results with previous data on cross-linking treatment.

RESULTS

94 ex vivo porcine corneas divided into 16 populations (healthy or injured, fresh or cultured and treated or not with plasma or cross-linking) were analysed. For each population, a biomechanical analysis was performed by uniaxial stress-relaxation tests, and a statistical analysis was carried out considering the characteristic mechanical parameters. In terms of equilibrium normalised stress, no statistically significant difference resulted when the healthy corneas were compared with lesioned plasma-treated ones, independently of treatment time, contrary to what was obtained about the cross-linking treated corneas which exhibited more intense relaxation phenomena.

CONCLUSIONS

In this study, the influence of the Helium plasma treatment was observed on the viscoelasticity of porcine corneas ex vivo, by restoring in lesioned tissue a degree of relaxation similar to the one of the native tissue, even after only 2 min of application. Therefore, the obtained results suggest that plasma treatment is a promising new regenerative ophthalmic therapy for melting corneal ulcers, laying the groundwork for further studies to correlate the mechanical findings with corneal histology and ultrastructural anatomy after plasma treatment.

Assessment of the quality of the healing process in experimentally induced skin lesions treated with autologous platelet concentrate associated or unassociated with allogeneic mesenchymal stem cells: preliminary results in a large animal model

Regenerative medicine for the treatment of skin lesions is an innovative and rapidly developing field that aims to promote wound healing and restore the skin to its original condition before injury. Over the years, different topical treatments have been evaluated to improve skin wound healing and, among them, mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) have shown promising results for this purpose. This study sought to evaluate the quality of the healing process in experimentally induced full-thickness skin lesions treated with PRP associated or unassociated with MSCs in a sheep second intention wound healing model. After having surgically created full-thickness wounds on the back of three sheep, the wound healing process was assessed by performing clinical evaluations, histopathological examinations, and molecular analysis. Treated wounds showed a reduction of inflammation and contraction along with an increased re-epithelialization rate and better maturation of the granulation tissue compared to untreated lesions. In particular, the combined treatment regulated the expression of collagen types I and III resulting in a proper resolution of the granulation tissue contrary to what was observed in untreated wounds; moreover, it led to a better maturation and organization of skin adnexa and collagen fibers in the repaired skin compared to untreated and PRP-treated wounds. Overall, both treatments improved the wound healing process compared to untreated wounds. Wounds treated with PRP and MSCs showed a healing progression that qualitatively resembles a restitutio ad integrum of the repaired skin, showing features typical of a mature healthy dermis.

Case Report: Repeated Intralesional Injections of Autologous Mesenchymal Stem Cells Combined With Platelet-Rich Plasma for Superficial Digital Flexor Tendon Healing in a Show Jumping Horse

In the present case report a show jumping 10-year-old Sella Italiano gelding, presented with severe lameness, swelling and pain at palpation of the mid-metacarpal region of the left forelimb. Clinical and ultrasound examination diagnosed a chronic tendonitis of the central region of the superficial digital flexor tendon (SDFT). The lesion was a reoccurrence since it developed from a previously healed injury. The horse had to stop competing and was unresponsive to gold-standard treatments as Non-steroidal anti-inflammatory drugs (NSAIDs) and conservative management after 6 months of therapy. The animal was subjected to repeated intralesional injections of autologous adipose-derived mesenchymal stem cells (AD-MSCs) combined with autologous platelet-rich plasma (PRP). The combined treatment was administered twice in a 1-month interval. The healing process was assessed through clinical examination, ultrasound imaging and quantification of oxidative stress products and inflammatory mediators in blood plasma. After 2 weeks from first injection, a reduction of concentration of oxidative-derived products was observed, together with an increase of anti-inflammatory cytokines and pro-mitotic growth factors. These results were reflected clinically as the horse showed a reduction of lameness along with swelling and pain after 4 weeks. At the 1-year follow-up, the horse showed no signs of lameness and swelling. The ultrasonographic examination highlighted a compact fiber alignment with a normal echogenic tendon as observed in the sound contralateral limb. Moreover, the horse went back to the previous level of competition. Our results suggest the positive effects of a repeated intralesional injection of AD-MSCs and PRP for the treatment of a chronic tendonitis with long-term effects and an improvement for both equine quality of life and athletic performance.

Mechanical behaviour of healthy versus alkali-lesioned corneas by a porcine organ culture model

BACKGROUND

Cornea is a composite tissue exhibiting nonlinear and time-dependent mechanical properties. Corneal ulcers are one of the main pathologies that affect this tissue, disrupting its structural integrity and leading to impaired functions. In this study, uniaxial tensile and stress-relaxation tests are developed to evaluate stress-strain and time-dependent mechanical behaviour of porcine corneas.

RESULTS

The samples are split in two groups: some corneas are analysed in an unaltered state (healthy samples), while others are injured with alkaline solution to create an experimental ulcer (lesioned samples). Furthermore, within each group, corneas are examined in two conditions: few hours after the enucleation (fresh samples) or after 7 days in a specific culture medium for the tissue (cultured samples). Finally, another condition is added: corneas from all the groups undergo or not a cross-linking treatment. In both stress-strain and stress-relaxation tests, a weakening of the tissue is observed due to the imposed conditions (lesion, culture and treatment), represented by a lower stiffness and increased stress-relaxation.

CONCLUSIONS

Alkali-induced corneal stromal melting determines changes in the mechanical response that can be related to a damage at microstructural level. The results of the present study represent the basis for the investigation of traditional and innovative corneal therapies.

A Prototype Skin Substitute, Made of Recycled Marine Collagen, Improves the Skin Regeneration of Sheep

Simple Summary

Marine ecosystems are a huge source of unexplored “blue” materials for different applications. The edible part of sea urchin is limited, and the vast majority of the product ends up as waste. Our studies intend to fully recycle wastes from the food industry and reconvert them in high added-value products, as innovative biocompatible skin substitutes for tissue regeneration. The aim of the present work is to apply the pioneering skin substitute in in vivo experimental wounds to test its regenerative potential and compare it, in a future study, to the available commercial membranes produced with collagen of bovine, porcine, and equine origin. Results are encouraging since the skin substitute made with marine collagen reduced inflammation, promoted the deposition of granulation tissue, and enhanced a proper re-epithelialization with the adequate development of skin appendages. In summary, our findings might be of great interest for processing industries and biotech companies which transform waste materials in high-valuable and innovative products for Veterinary advanced applications.

Abstract

Skin wound healing is a complex and dynamic process that aims to restore lesioned tissues. Collagen-based skin substitutes are a promising treatment to promote wound healing by mimicking the native skin structure. Recently, collagen from marine organisms has gained interest as a source for producing biomaterials for skin regenerative strategies. This preliminary study aimed to describe the application of a collagen-based skin-like scaffold (CBSS), manufactured with collagen extracted from sea urchin food waste, to treat experimental skin wounds in a large animal. The wound-healing process was assessed over different time points by the means of clinical, histopathological, and molecular analysis. The CBSS treatment improved wound re-epithelialization along with cell proliferation, gene expression of growth factors (VEGF-A), and development of skin adnexa throughout the healing process. Furthermore, it regulated the gene expression of collagen type I and III, thus enhancing the maturation of the granulation tissue into a mature dermis without any signs of scarring as observed in untreated wounds. The observed results (reduced inflammation, better re-epithelialization, proper development of mature dermis and skin adnexa) suggest that sea urchin-derived CBSS is a promising biomaterial for skin wound healing in a “blue biotechnologies” perspective for animals of Veterinary interest.

Corneal sequestra in cats: 175 eyes from 172 cases (2000-2016)

OBJECTIVES

To report the clinical outcomes of different surgical treatments used to manage feline corneal sequestra in a large number of cases.

MATERIALS AND METHODS

Medical records of 172 cats affected by feline corneal sequestra and surgically managed by different techniques were retrospectively evaluated. Signalment, surgical technique, visual outcomes, postoperative corneal clarity and recurrence were evaluated.

RESULTS

One hundred and seventy-two cats (175 eyes) of different breeds, ages and sex were included in the retrospective case series. The Persian was the most represented breed (123/172; 71.5%), followed by Exotic Shorthair breed (21/172; 12.2%), Domestic shorthair breed (21/172; 12.2%) and a smaller group of other different breeds (7/172). Surgical management included a superficial (84/175 eyes) or deep (91/175 eyes) lamellar keratectomy in association with the following covering techniques (tectonic support and/or protective support): nictitans membrane flap (n=84), conjunctival pedicle graft (n=52), BioSISt graft (n=9), corneoconjunctival transposition (n=7), corneoconjunctival transposition+nictitans membrane flap (n=6), conjunctival free island graft (n=6), BioSISt+conjunctival pedicle graft (n=6), BioSISt+nictitans membrane flap (n=4) and bridge conjunctival graft (n=1). At the end of the retrospective case series, visus was present in all patients and no or mild corneal opacity was detected in 86% (151/175 eyes) of the patients. Sequestra recurred in 20 eyes (20/175; 11.4%) within 2 years.

CLINICAL SIGNIFICANCE

This paper describes the clinical outcomes of a large number of cases of feline corneal sequestra treated with varying surgical techniques and provides useful insight regarding the prognosis and outcomes of these techniques within feline ophthalmology.

Autologous Platelet-Rich Plasma Enhances the Healing of Large Cutaneous Wounds in Dogs

Platelet-rich plasma (PRP) is known to play a crucial role in skin wound healing, in both Human and Veterinary Medicine. Remarkably, until now, no studies have reported PRP treatment in subacute full-thickness skin wounds of the dog. The aim of this study was to evaluate the effects of two consecutive applications of autologous PRP, with the second application after 15 days, in 6 dogs showing large subacute skin wounds. The percentage of contraction, re-epithelialization and healing in all treated patients indicated that no complications or side effects, associated with consecutive PRP treatments, occurred in any patient and all wounds achieved complete closure and re-epithelialization. Our results suggest a positive effect of repeated autologous topical PRP treatments in large cutaneous subacute wounds of different etiology. Therefore, this PRP treatment could represent a simple, cost-effective, and valid alternative to promote healing processes in subacute large wounds cases in dogs.

Hyaluronic acid, Manuka honey and Acemannan gel: Wound-specific applications for skin lesions

Healing of open wounds is of great medical importance. Wound healing is a complex process that aims to restore the function and structure of damaged tissue. This study was conducted to compare secondary intention healing of wounds treated daily with a topical application of commercially available hyaluronic acid (HA), Manuka honey (MH), Acemannan gel (AG), or a placebo. Bilateral wounds were surgically created on the backs of six sheep. At two and six weeks post-wound creation, biopsies were obtained to perform histological, immunohistochemical, and molecular analyses of the wound site. Daily clinical evaluations were performed and weekly photographs were taken of the wounds. HA treatment promoted a physiological progression of the healing process in all wound healing phases, while stimulating an abundant cutaneous adnexa and promoting rapid healing, representing the most compelling treatment. MH-treated wounds were slightly dry. However, the main effect of MH was to promote cell proliferation and neovascularization, with an overall pro-inflammatory effect. Results suggest that MH treatment enhances the healing process. AG treatment dehydrated the wounds and stimulated late granulation tissue and cell proliferation. Moreover, AG-treated wounds produced a mild late pro-inflammatory and neovascularization effect. Our data indicate that AG treatment can have a positive influence on moist wounds with abundant granulation tissue and exudate.

Impression cytology of the healthy equine ocular surface: Inter-observer agreement, filter preservation over time and comparison with the cytobrush technique

BACKGROUND

The cytobrush technique is commonly used to sample the equine ocular surface. Impression cytology (IC) is an innovative noninvasive method, which allows for the collection of superficial layers of ocular epithelium.

OBJECTIVES

The aims of this study were to compare the cytobrush and IC techniques on healthy equine ocular surfaces, to assess the agreement between observers with different levels of expertise, and to test the preservability of filters over time.

METHODS

Twenty-four horses were sampled within 10 minutes of slaughter using IC on the left eye and the cytobrush technique on the right eye. May-Grünwald-Giemsa stained specimens were evaluated by two observers with different levels of expertise. Morphologic features were evaluated using a 4-grade system. The IC samples were re-evaluated after 6 months to examine filter preservation.

RESULTS

In IC samples, corneal and conjunctival cells were clearly separated. Goblet cells were found in five and 17 filters by observer 1 and 2, respectively. Using the cytobrush technique, corneal and conjunctival cells were present but mixed. Goblet cell cellularity, preservation, and enumeration were higher with the IC technique compared with the cytobrush technique (P = 0.013; P = 0.004; P = 0.031, respectively). The inter-observer agreement for the IC technique was moderate to fair. In 7/24 IC samples re-evaluated after 6 months, cellular morphology was impaired, and the overall score was significantly lower.

CONCLUSIONS

IC is an innovative noninvasive method, which allows for sample collection with higher cellularity and preservation. Moreover, the identification of goblet cells is easier. For these reasons, IC could be interesting and useful as a complementary diagnostic cytologic method in clinical practice.

Effect of storage on long-term stability of salivary α-amylase, lysozyme, lactate dehydrogenase, calcium and phosphorus in dogs

Research or diagnostic conditions may require the storage of salivary samples for long periods before analysis is processed. The aim of this study was to evaluate the stability of canine salivary α-amylase, lysozyme, lactate dehydrogenase (LDH), and total calcium and phosphorus after storage for 1, 3 and 6 months at -20°C. Available saliva samples were 75 immediately after collection (T0) and 46 at 1 month (T1), 31 at 3 months (T3) and 18 at 6 months (T6) of storage, according to the number of aliquots collected from each saliva sample. Compared to T0, LDH declined by 92.3% after 1 month of storage (P<0.001), whereas lysozyme concentration significantly decreased as storage time increased (-29.3%, -43.4% and -59.1% at T1, T3, and T6 respectively, P<0.001). Amylase maintained basically the same concentration for the entire experimental period, whereas total calcium and phosphorus concentration decreased over time (calcium, P<0.001). Assessing the long-term stability of canine salivary analytes stored at -20°C may have important implications in diagnosis and research.

Maxillomandibulocardiac reflex in a dog

Background

The trigeminocardiac reflex (TCR) is a brainstem reflex that may be observed in anaesthesia during surgical procedures stimulating the intracranial or peripheral portion of the trigeminal nerve. The peripheral TCR is divided into the oculocardiac reflex and the maxillomandibulocardiac reflex based on the affected sensory branches of the trigeminal nerve. In veterinary medicine the oculocardiac reflex has been described, however the maxillomandibulocardiac reflex has never been reported.

Case presentation

A 5-year-old male Epagneul Breton was presented for surgical management of an upper lip mass. During surgery, a sudden severe bradycardia and a decrease in systemic arterial blood pressure developed. The occurrence of a maxillomandibulocardiac reflex was suspected on the basis of the temporary link between surgical stimulation and haemodynamic changes. Three doses of atropine were given before starting a dopamine infusion due to lack of response. The dopamine infusion normalized heart rhythm and blood pressure. The dog recovered uneventfully and he was discharged 24 h later with a sinus rhythm and no sign of recurrence of arrhythmias.

Conclusion

The TCR is a rare but potentially life-threatening complication of procedures involving the sensory areas innervated by the three branches of the trigeminal nerve and it may cause bradycardia with hypotension. The use of a β1-adrenergic receptor agonist such as dopamine may be indicated in cases of a refractory response to the conventional treatment with atropine.

Allogeneic mesenchymal stem cells improve the wound healing process of sheep skin

BACKGROUND

Skin wound healing includes a system of biological processes, collectively restoring the integrity of the skin after injury. Healing by second intention refers to repair of large and deep wounds where the tissue edges cannot be approximated and substantial scarring is often observed. The objective of this study was to evaluate the effects of mesenchymal stem cells (MSCs) in second intention healing using a surgical wound model in sheep. MSCs are known to contribute to the inflammatory, proliferative, and remodeling phases of the skin regeneration process in rodent models, but data are lacking for large animal models. This study used three different approaches (clinical, histopathological, and molecular analysis) to assess the putative action of allogeneic MSCs at 15 and 42 days after lesion creation.

RESULTS

At 15 days post-lesion, the wounds treated with MSCs showed a higher degree of wound closure, a higher percentage of re-epithelialization, proliferation, neovascularization and increased contraction in comparison to a control group. At 42 days, the wounds treated with MSCs had more mature and denser cutaneous adnexa compared to the control group. The MSCs-treated group showed an absence of inflammation and expression of CD3+ and CD20+. Moreover, the mRNA expression of hair-keratine (hKER) was observed in the MSCs-treated group 15 days after wound creation and had increased significantly by 42 days post-wound creation. Collagen1 gene (Col1α1) expression was also greater in the MSCs-treated group compared to the control group at both days 15 and 42.

CONCLUSION

Peripheral blood-derived MSCs may improve the quality of wound healing both for superficial injuries and deep lesions. MSCs did not induce an inflammatory response and accelerated the appearance of granulation tissue, neovascularization, structural proteins, and skin adnexa.

Investigations of the corneal epithelium in Veterinary Medicine: State of the art on corneal stem cells found in different mammalian species and their putative application

The existence of progenitor cells that can readily differentiate into a specific cell type is a common cellular strategy for physiological tissue growth and repair mechanisms. In the mammalian cornea, many aspects regarding the nature and location of these cells are still unclear. In the human limbus (peripheral area of the cornea) progenitor cells have been found and characterized but in non-human mammals, the picture is not so clear. In this review, we examine current knowledge about the morphology of limbus and the localization of corneal epithelial stem cells in all species studied so far, comparing data with humans. We have also explored different research directions in the veterinary field in order to discuss the: i) currently used protocols and ii) best range of treatments for ocular pathologies in which corneal stem cells are involved.

Salivary pH, calcium, phosphorus and selected enzymes in healthy dogs: a pilot study

BACKGROUND

Saliva in dogs, as in humans, is a complex fluid secreted by different salivary glands in the oral cavity to protect the oral mucosa and teeth. The use of saliva as a substitute for blood in diagnosing and prognosticating disease in humans is widely accepted. Salivary biochemistry has also been used as a marker for periodontal disease in humans. No studies have as yet investigated the relation between salivary biochemistry and periodontal disease in dogs, however; neither has the salivary composition of healthy dogs with no oral disease been assessed. The purpose of this study was to obtain an overview on pH distribution and a set of salivary biochemical analytes (calcium, phosphorus, lactate dehydrogenase, lysozyme and amylase) commonly related to oral health in humans in a subset population of healthy young dogs with no periodontal disease or previous oral disease. Data were analyzed to gather salivary reference ranges for pH and each parameter and to assess a possible correlation between salivary and serum analytes.

RESULTS

Twenty-nine adult client-owned dogs were recruited for the study. Lactate dehydrogenase and lysozyme showed higher concentrations in saliva than in serum, whereas amylase showed the contrary. Salivary biochemistry values did not differ between males and females or between non-neutered and neutered individuals. No significant correlations between salivary and serum calcium, phosphorus, lactate dehydrogenase, amylase and lysozyme were identified in this study. Data allowed intervals for the salivary pH and other analytes investigated to be obtained from healthy dogs with healthy oral conditions.

CONCLUSIONS

These preliminary data can contribute to enlarge our understanding of the functional role of saliva and its relation to oral health in dogs.

Use of canine sourced platelet-rich plasma in a feline contaminated cutaneous wound

A 4-year-old neutered female domestic shorthaired cat was treated with canine sourced platelet-rich plasma at the Veterinary Hospital at University of Padua for a large skin defect on the left lateral neck region. The wound healed completely within 20 days and no adverse reaction was observed during the healing process.

Cytology of the healthy canine and feline ocular surface: comparison between cytobrush and impression technique

BACKGROUND

Impression cytology (IC) is a noninvasive technique in which filters are used to sample superficial layers of ocular epithelium.

OBJECTIVES

The aim of this study was to compare cytology specimens obtained by IC and cytobrush from healthy canine and feline eyes.

METHODS

Dogs and cats were prospectively sampled using polytetrafluorethylene filters on the right eye, and cytobrush on the left eye. Wright-Giemsa-stained specimens were evaluated by 2 observers. Cellularity, preservation, and morphology of cells and presence of goblet and inflammatory cells were scored with a 4-grade scale. Inter-observer agreement and effects of topical anesthesia were analyzed.

RESULTS

In 20 canine IC samples, 10 showed good cellularity (score 2-3) and 13 good preservation. Superficial epithelial cells (SEC) were present in 13/20 of IC, while basal-intermediate cells (BIC) were seen in 14/20. In 6/20 and 7/20, goblet and inflammatory cells were noted, respectively. In 20 cats, 15 of IC showed good cellularity and 14 good preservation, and SEC were present in 16/20 of IC and BIC in 17/20. In 13/20 and 3/20 cats, goblet cells and inflammatory cells were noted, respectively. Canine cytobrush specimens appeared well preserved (9/20) and had good cellularity (8/20). In feline cytobrush specimens, good preservation and cellularity were observed in 16/20 and 14/20, respectively. In both species, all cell types were present without a clear separation. There was moderate to fair agreement about cellular morphology in IC between observers. Specimens obtained with and without anesthesia were comparable.

CONCLUSION

Impression cytology allowed collection of samples with maintained cytoarchitecture, while cytoplasmatic and nuclear details were often difficult to evaluate.

Effect of MLS(®) laser therapy with different dose regimes for the treatment of experimentally induced tendinopathy in sheep: pilot study

OBJECTIVE

The aim of this preliminary study was to investigate the effect of Multiwave Locked System (MLS(®)), a particular model of low-level laser, in the acute phase of collagenase-induced tendon lesions in six adult sheep randomly assigned to two groups.

BACKGROUND DATA

Tendon injuries are common among human athletes and in sport horses, require a long recovery time, and have a high risk of relapse. Many traditional treatments are not able to repair the injured tendon tissue correctly. In recent years, the use of low-level laser therapy (LLLT) produced interesting results in inflammatory modulation in different musculoskeletal disorders.

METHODS

Group 1 received 10 treatments of MLS laser therapy at a fluence of 5 J/cm(2) on the left hindlimb. Group 2 received 10 treatments of MLS laser therapy at a fluence of 2.5 J/cm(2) on the left hindlimb. In every subject in both groups, the right hindlimb was considered as the control leg.

RESULTS

Clinical follow-up and ultrasonography examinations were performed during the postoperative period, and histological examinations were performed at day 30 after the first application of laser therapy. In particular, results from histological examinations indicate that both treatments induced a statistically significant cell number decrease, although only in the second group did the values return to normal. Moreover, the MLS laser therapy dose of 2.5 J/cm(2) (group 2) caused a significant decrease of vessel area.

CONCLUSIONS

In this study, clinical and histological evaluation demonstrated that a therapeutic dose <5 J/cm(2) furnished an anti-inflammatory effect, and induced a decrease of fibroblasts and vessel area. Overall, our results suggest that MLS laser therapy was effective in improving collagen fiber organization in the deep digital flexor tendon.

Might the Masson trichrome stain be considered a useful method for categorizing experimental tendon lesions?

Strain injuries of tendons are the most common orthopedic injuries in athletic subjects, be they equine or human. When the tendon is suddenly damaged, an acute inflammatory phase occurs whereas its repetitive overloading may cause chronic injuries. Currently the criteria used for grading injuries are general and subjective, and therefore a reliable grading method would be an improvement. The main purpose of this study was to assess qualitatively the histological pattern of Masson trichrome stain in healthy and injured tendons; indeed, the known "paradox" of Masson staining was used to create an evaluation for the matrix of tendons, following experimental lesions and natural repair processes. A statistically significant difference of aniline-staining between healthy and lesioned tendons was observed. Overall, we think that the Masson staining might be regarded as an informative tool in discerning the collagen spatial arrangement and therefore the histological characteristics of tendons.

Multiple dermoid sinuses of type Vb and IIIb on the head of a Saint Bernard dog

Dermoid sinus, a congenital malformation of neural tube development, has been reported in humans and several animal species including dogs. It is typically found in the dorsal midline and commonly occurs in the Rhodesian Ridgeback breed. A case of multiple dermoid sinuses in the fronto-occipital region is described. An 11-month-old, intact female Saint Bernard dog was presented with a 2 day history of discharge from a large irregular subcutaneous mass in the fronto-occipital region. The dog was otherwise healthy. The dog had two circular skin lesions (approximately 4 × 4 and 4 × 2 cm diameter) surrounded by multiple irregular elevated masses. The masses had multiple small openings on the skin surface with tufts of hair protruding from the apertures. The masses were surgically removed, and the diagnosis of multiple dermoid sinuses was confirmed by histological examination. Histopathological examination showed multiple, variably sized, spherical to tubular cysts expanding the dermis and subcutis. Cysts were filled with hair shafts and lamellar keratin and were lined by a stratified squamous epithelium. Sebaceous and apocrine gland adnexal structures were also observed. To the best of our knowledge, this is the first reported case of multiple dermoid sinuses of two different types in the head of a Saint Bernard dog.

Description of a double centrifugation tube method for concentrating canine platelets

Background

To evaluate the efficiency of platelet-rich plasma preparations by means of a double centrifugation tube method to obtain platelet-rich canine plasma at a concentration at least 4 times higher than the baseline value and a concentration of white blood cells not exceeding twice the reference range. A complete blood count was carried out for each sample and each concentrate. Whole blood samples were collected from 12 clinically healthy dogs (consenting blood donors). Blood was processed by a double centrifugation tube method to obtain platelet concentrates, which were then analyzed by a flow cytometry haematology system for haemogram. Platelet concentration and white blood cell count were determined in all samples.

Results

Platelet concentration at least 4 times higher than the baseline value and a white blood cell count not exceeding twice the reference range were obtained respectively in 10 cases out of 12 (83.3%) and 11 cases out of 12 (91.6%).

Conclusions

This double centrifugation tube method is a relatively simple and inexpensive method for obtaining platelet-rich canine plasma, potentially available for therapeutic use to improve the healing process.

Cavernous sinus syndrome due to osteochondromatosis in a cat

A 1-year-old sexually intact male Korat cat was referred for ophthalmological consultation due to anisocoria. Mydriasis with external ophthalmoplegia and absence of pupillary light responses in the right eye and nasofacial hypalgesia were seen. Cavernous sinus syndrome (CSS) was suspected. Bilateral deformities of the jaw and phalangeal bones, severe spinal pain and abnormal conformation of the lumbar spine were also present. Radiographic examination revealed several mineralised masses in the appendicular and axial skeleton, indicative of multiple cartilaginous exostoses. For further investigation of the CSS-related neurological deficits, the cat underwent computed tomography (CT) examination of the skull. CT images revealed a non-vascularised, calcified, amorphous mass originating from the right lateral skull base and superimposing on the sella turcica. Based on the severity of diffuse lesions and owing to the clinical signs of extreme pain, the cat was euthanased. A diffuse skeletal and intracranial osteochondromatosis was diagnosed histologically.

Effects of in vivo applications of peripheral blood-derived mesenchymal stromal cells (PB-MSCs) and platlet-rich plasma (PRP) on experimentally injured deep digital flexor tendons of sheep

Tendon injuries, degenerative tendinopathies, and overuse tendinitis are common in races horses. Novel therapies aim to restore tendon functionality by means of cell-based therapy, growth factor delivery, and tissue engineering approaches. This study examined the use of autologous mesenchymal stromal cells derived from peripheral blood (PB-MSCs), platelet-rich plasma (PRP) and a combination of both for ameliorating experimental lesions on deep digital flexor tendons (DDFT) of Bergamasca sheep. In particular, testing the combination of blood-derived MSCs and PRP in an experimental animal model represents one of the few studies exploring a putative synergistic action of these treatments. Effectiveness of treatments was evaluated at 30 and 120 days comparing clinical, ultrasonographic, and histological features together with immunohistochemical expression of collagen types 1 and 3, and cartilage oligomeric matrix protein (COMP). Significant differences were found between treated groups and their corresponding controls (placebo) regarding tendon morphology and extracellular matrix (ECM) composition. However, our results indicate that the combined use of PRP and MSCs did not produce an additive or synergistic regenerative response and highlighted the predominant effect of MSCs on tendon healing, enhanced tissue remodeling and improved structural organization.

Immunohistochemical localization of atrial natriuretic factor and autoradiographic distribution of atrial natriuretic factor-binding sites in the brain of the cave salamander Hydromantes genei (Amphibia, Plethodontidae)

The distribution of atrial natriuretic factor (ANF)-like immunoreactivity in the central nervous system of the cave salamander Hydromantes genei (Amphibia, Plethodontidae) was investigated by using antisera raised against rat and human ANF(1-28). Concurrently, the location of ANF-binding sites was determined by autoradiography, using radioiodinated human ANF(1-28) as a tracer. In several regions of the brain, including the olfactory bulb, the preoptic area, the ventral thalamus, the tectum of the mesencephalon, and the choroid plexuses inside the ventricles, a good correlation was observed between the distribution of ANF-immunoreactive elements and the location of ANF-binding sites. Mismatching was found in the habenular nucleus, the commissura habenularis, the fasciculum retroflexus, and the interpeduncular nucleus, which contained high levels of binding sites but were devoid of ANF-immunoreactive structures. In contrast, a few other regions, such as the pineal gland and the subcommissural organ, showed a high concentration of ANF-like immunoreactivity but did not contain ANF-binding sites. This study provides the first localization of ANF-like immunoreactivity and ANF-binding sites in the brain of an urodele amphibian. The results show that the ANF peptidergic system in the cave salamander has an organization more simple than the organizations described for the brain of frog or other vertebrates. This feature is probably related to the expression of highly pedomorphic characters in plethodontids. The anatomical distribution of ANF-immunoreactive elements and ANF-binding sites suggests that ANF-related peptides may act as hypophysiotropic hormones as well as neurotransmitters and/or neuromodulators in the salamander brain.

Metabolic pathways of the anti-hypertensive agent, N-(2,5-dimethyl-1H-pyrrol-1-yl)-6-(4-morpholinyl)-3-pyridazinamine hydrochloride. II: Studies in the dog

The metabolic fate of a new anti-hypertensive, 1-pyrrolyl-pyridazinamine, was studied in male Beagle dogs given both p.o. and i.v. doses of the 14C-labelled drug (1 mg/kg). The compound given as a single i.v. injection disappeared from the central compartment with a half-life of about 0.9 h. Plasma levels of total 14C were represented mostly by metabolites. Eight urinary metabolites designated as metabolites I, II and XI-XVI were purified and their structures assigned by means of u.v., i.r., n.m.r. and mass spectrometry. Quantitatively the primary metabolic attack involved the morpholine moiety of the molecule which undergoes oxidative opening. A minor pathway afforded the cleavage of the pyrrole followed by chemical rearrangements to form six-membered sidnone-like products or a triazole derivative. The major (XIII) and three minor metabolites were studied for their antihypertensive activity in rats and were shown to be inactive.

Metabolic pathways of the anti-hypertensive agent, N-(2,5-dimethyl-1H-pyrrol-1-yl)-6-(4-morpholinyl)-3-pyridazinamine+ ++ hydrochloride. I. Studies in the rat

The metabolic fate of a new anti-hypertensive, 1-pyrrolyl pyridazinamine, was studied in male Wistar rats after both p.o. and i.v. administration (1 mg/kg). The compound undergoes rapid metabolism, disappearing from the central compartment with a half-life of about 0.5 h. Plasma concn. of the parent drug and its major metabolite I following i.v. and p.o. administration suggest a route-dependent first-pass metabolism. Ten metabolites were isolated from the urine and identified by u.v., i.r., mass and 1H-n.m.r. spectroscopy. The structure of some was confirmed by 13C-n.m.r. and chemical synthesis. All biotransformations are restricted to the pyrrole ring which undergoes oxidative cleavage followed by a series of chemical rearrangements. A minor pathway leads to the formation of methyl sulphinyl and methyl sulphonyl pyrroles. It is suggested that, as with natural indoles, the pyrrole might be oxidized by a 2,3-dioxygenase. The three major metabolites, I, II and IX, along with two minor ones, VI and VII, were inactive when tested i.v. for antihypertensive activity.

Pharmacokinetics and metabolism of tomoxiprole, a new analgesic antiinflammatory agent, in the rat

The pharmacokinetics and the metabolic profile of tomoxiprole, a new analgesic antiinflammatory agent belonging to the class of 3-alkyl-2-aryl-3H-naphth (1,2-d)imidazoles, were studied in the rat. After oral administration (5 mg/kg) to male rats, tomoxiprole was rapidly absorbed, mostly by the gut, and reached maximum plasma levels of about 0.5 microgram/ml in 0.25-2 h. A metabolic first pass reduced the extent of oral bioavailability of the parent compound to about half, while absorption (total 14C data) was estimated to be complete. After intravenous injection (2.5 mg/kg), the plasma kinetics of tomoxiprole in male rats showed a bi-exponential profile, and the terminal elimination half-life was 4.2 h. The apparent volume of distribution was high, suggesting a wide distribution of the drug. Increasing the oral dose by ten times (50 mg/kg), resulted in linear kinetics with a proportional increase of the C max and AUC values and the same value of terminal elimination half-life. In females given a 5 mg/kg dose, the plasma levels of 14C, tomoxiprole and AUC values were somewhat higher than in males. The plasma levels of total 14C after iv or po treatments were higher and more sustained than those of tomoxiprole. The kinetic profile after iv administration was described by a three exponential terms equation and the terminal elimination half-life was 38.7 h. Upon iv administration, total 14C was rapidly distributed in highly vascularized tissues while in others, like the bone, fat, gonads, pancreas and skin the equilibrium with the central compartment was attained later. Target organs were the adrenals, liver, lungs, pancreas, thyroid, stomach and above all the fat tissue. Elimination from tissues was almost complete 48 h after the treatment. 14C was eliminated mainly in the feces (80% of dose) as metabolites. In the bile, five polar metabolites were detected; one of them, desmethyl tomoxiprole glucuronide, accounting alone for more than 80% of the total biliary radioactivity; was purified and its structure assigned.

Metabolic fate of zetidoline, a new neuroleptic agent, in man

Healthy volunteers administered orally a single dose (20 mg) of [2-14C]zetidoline, a new dopamine antagonist, exhibited rapid absorption of radioactivity with peak plasma levels of 250-300 ng/ml achieved in 1 h. The compound underwent intensive metabolic first-pass so that plasma radioactivity was represented mostly by two products, metabolite B endowed with neuroleptic activity, and metabolite D inactive, while unchanged zetidoline was not detected. Disappearance of radioactivity from plasma was rapid with a half-life of 1.78 +/- 0.20 h. The simultaneous assay of plasma prolactin showed increased levels of the hormone (+ 464% at the peak time) up to the 6th h after dosing, with plasma concentration profile which mimic those of metabolite B. The radioactive test-dose was eliminated mainly via the kidneys with an average urinary recovery of 84.7 +/- 1.7% in 4 days (73.4 +/- 1.1% within 8 h). The main urinary metabolite (metabolite G) and two minor ones (metabolites B and D) were purified and their structures assigned by IR, MS and NMR spectroscopy, they are: 1-(3-chloro-4-hydroxyphenyl)-3 [2-(3,3-dimethyl-1-azetidinyl)ethyl]imidazolidin-2-one, metabolite B; 1-[2-(3,3-dimethyl-1-azetidinyl)ethyl]-imidazolidin-2-one, metabolite D and the 4'-O-sulphate ester of metabolite B, metabolite G. The metabolic fate of zetidoline in man follows the same phase I reactions demonstrated in rats and dogs, while the phase II reaction is sulphoconjugation instead of the glucuronidation observed in animals.

Metabolism of the neuroleptic agent zetidoline in the rat and the dog

The metabolism of zetidoline, a new neuroleptic, in the rat and the dog has been studied. From the urine of rats and dogs given 5 mg/kg of [2-14C] zetidoline orally, unchanged drug and five metabolites were isolated and the structures of four of them assigned by physicochemical analysis. They are: metabolite B, 4'-hydroxy-3'-chlorophenyl zetidoline; metabolite D, zetidoline without the aryl group; metabolite E, the 6'-hydroxy-4'-beta-D-glucuronide of metabolite B, and metabolite F, the 4'-beta-D-glucuronide of metabolite B. The plasma levels of zetidoline and its metabolites after iv administration show that the drug is rapidly excreted and/or metabolized in both animal species. The plasma radioactivity in the dog consists mainly of the pharmacologically active (neuroleptic) metabolite B, whereas in the rat it consists of the more polar metabolites. After oral administration, elimination in both species occurs mostly via the kidneys. In the dog, within a 24-hr period, 6.2 +/- 0.4% of the dose is accounted for as unchanged zetidoline, 7.6 +/- 0.5% as metabolite B, 10.1 +/- 0.7% as the unidentified metabolite C, and 21.4 +/- 1.1% as metabolite F. In the rat, over the same period, zetidoline is present in traces, metabolite B accounts for 6.9 +/- 0.3% of the dose, metabolite D for 6.6 +/- 0.9%, metabolite E for 15.2 +/- 1.4%, and metabolite F for 31.7 +/- 2.2%.

Metabolic pathways of the contragestational agent, 3-(2-ethylphenyl)-5-(3-methoxyphenyl)-1H-1,2,4-triazole (DL 111-IT), in the rat

The metabolic pathways of the non-hormonal anti-fertility agent 3-(2-ethylphenyl)-5-(3-methoxyphenyl)-1H-1,2,4-triazole (DL 111-IT) were studied in rats given the 14C-labelled compound intramuscularly. The diaryltriazole, once absorbed, was metabolized rapidly by three phase I reactions: (a) hydroxylation at the C-4 of the methoxyphenyl ring, (b) hydroxylation at the alpha-C of the ethyl chain, and (c) demethylation of the methoxyl function. Seven free metabolites and three conjugates have been isolated and characterized by u.v., i.r., n.m.r. and mass spectroscopy. The products of the first step of metabolism of the diaryltriazole were tested for their pregnancy-terminating activity in the rat. They were only 5-9% as effective as the parent compound, indicating that the unchanged drug is the active molecule.

Pharmacokinetics and metabolism of premazepam, a new potential anxiolytic, in humans

Premazepam, a pyrrolodiazepine with potential anxiolytic properties, behaves as a partial antagonist to diazepam in animal tests. Its pharmacokinetics and metabolism were studied in four healthy volunteers. After oral administration of 30 mg [6-14C] premazepam, the plasma levels of total radioactivity reached maximum concentrations 1-4 h (mean 2 h) following administration. The plasma curve was described by an open one-compartment model, and half-life was 11.5 +/- 1.3 h. Levels of the unchanged compound accounted for about 80% of the total radioactivity up to 24 h. Half-life of the unchanged compound was 7.9 +/- 1.2 h. On the average, 89.6% of the administered radioactivity was recovered in the urine and 2.3% in the feces during the 5 days following administration. Unchanged premazepam accounted for about 70% of the total radioactivity excreted in the urine. Of the three metabolites identified in the urine, none was active in vitro in displacing 3H-diazepam from its forebrain receptors in the rat, indicating that only the parent compound has definite pharmacologic activity.

Metabolic fate of premazepam, a new anti-anxiety drug, in the rat and the dog

A study of the disposition and metabolism of premazepam, 3,7-dihydro-5-phenyl-6,7-dimethyl-pyrrole[3,4-e][1,4]diazepin-2-(1 H) -one, a new anti-anxiety agent, was carried out in rats and dogs given the 14C-labeled compound iv and po. In both species, after oral administration, both total radioactivity and the unchanged drug are rapidly absorbed and peak plasma levels are reached within 0.5-1 hr in rats and 2 hr in dogs. Unchanged premazepam is cleared faster in rats than in dogs, with half-lives about 1.7 and 2.7 hr, respectively. Following oral dosage, two-thirds of the dose is eliminated in urine. From the urine of the two species, eight metabolites and unchanged premazepam were identified. N-7-Desmethyl premazepam (l) is the major metabolite in rat urine (18% of the dose) but is not present in dog urine, while 6-hydroxymethyl premazepam is the most abundant metabolite in dog urine (25% of the dose) but is absent in rat urine. Metabolites III and IV from rat and dog urine are stable derivatives of the intermediate formed by the cleavage of the imine bond of the diazepine ring. A successive hydrolysis of the amidic bond of the same intermediate originates metabolites V-VIII, which are quantitatively minor ones.

Disposition and metabolism of a new steroidal anti-inflammatory agent, deflazacort, in cynomolgus monkeys

The kinetics and metabolic fate of 2'-14C-deflazacort, a new steroidal antiinflammatory agent, were studied in the cynomolgus monkey after both p.o. and i.v. administration (5 mg/kg). There is no unchanged deflazacort in the plasma or urine after either p.o. or i.v. treatment. As judged from the plasma AUC and urinary elimination values, the oral availability of both total 14C and metabolites seems to be lowered because of a route-dependent first-pass. Both radioactivity and the main metabolite (21-desacetyl deflazacort) are eliminated from the plasma with half-lives of 2--3-5 h. The i.v. administered 14C is eliminated mainly in the urine (52--55% of dose), but biliary excretion is also quantitatively important. Six metabolites were isolated from urine and identified by physico-chemical analysis. Among them desacetylated deflazacort and its 6 beta-hydroxy derivative were shown to be the major radioactive products in plasma and urine, respectively. Minor metabolites were: 21-desacetyl, 6 alpha-hydroxy deflazacort; 21-desacetyl, 5 alpha, 1-eno, deflazacort; 21-desacetyl, 20 beta hydroxy deflazacort; and 21-desacetyl, 11-keto deflazacort.

Pharmacokinetics-activity relationships of a new non-hormonal antifertility agent: 3-(2-ethylphenyl)-5-(3-methoxyphenyl)-1H-1, 2,4-triazole, in the rat and the hamster

The pharmacokinetic profiles of a new non-hormonal anti-fertility agent, DL 111-IT, were studied in rats and hamsters given the 14C labelled compound parenterally dissolved in aqueous or oily vehicles. In both species, DL 111-It was rapidly metabolized and excreted when given intravenously or subcutaneously in aqueous vehicles (half-lives = 15-45 min.), whereas the kinetics were prolonged when it was administered in oily formulations (half-lives = 7-10 h). Binding studies revealed a high affinity of DL 111-IT for rat serum albumin (Ka = 6 X 10(5) 1/mole). The radioactivity concentrations in different tissues of pregnant rats appeared to be uniform with the excretory organs and lungs being the main target tissues. At the site of action, the utero-placental complex, the levels of total 14C were comparable to those in plasma, whereas the concentration of unchanged DL 111-IT was higher and remained so for a longer time. A comparison between the kinetic profiles and the activity data after single or multiple dose administration in different formulations, clearly indicates a close relationship between activity and plasma and tissue (utero-embryo placental complex) levels of DL 111-IT, and also makes clear the influence of the formulation and of the treatment schedule on the anti-fertility activity of the compound.

Species differences in the disposition and metabolism of 1-methyl-3-(3-pyridyl)-5-(2-hydroxy-methylphenyl)-1H-1,2,4-triazole, a potential sedative-hypnotic compound

1. Disposition and metabolism of 1-methyl-3-(3-pyridyl)-5-(2-hydroxy-methylphenyl)-1H-1,2,4-triazole, a new sedative-hypnotic, were studied in rats (i.v. and p.o.), cats (i.v.) and human volunteers (p.o.) with 14C-labelled drug. 2. In rat and man, the compound is well absorbed, extensively metabolized, and excreted mostly through the kidney; it has short plasma half-lives, 0.6 h in rat, 0.9 h in man, and 1.9 h in cat. 3. In rat and man metabolism involves N-oxidation of the pyridine ring (Metabolite I), and in cat oxidation of the hydroxymethyl group (Metabolite II). Four other conjugated metabolites (III-VI) isolated from rat urine and bile, and from urine of cats and man, have been characterized. 4. The unchanged compound, but not its metabolites, crosses the blood-brain barrier in rat and cat. 5. The species differences in the disposition and metabolism of the compound are consistent with previous pharmacological data indicating a greater and more prolonged effect in cat.

Metabolism of deflazacort in the rat, dog and man

The metabolism of [2'-14C]deflazacort, (11 beta, 16 beta)-21-(acetoxyl)-11-hydroxy-2'-methyl-5'H-pregna-1, 4-dieno[17,16-d]oxazole-3,20-dione, orally given to rats, dogs, and humans, has been studied. From the urine of the three species and from rat bile and liver preparations, five main metabolites I-V have been isolated and their structures investigated by physicochemical analysis: 1,(5 beta,11 beta,16 beta)-11,21-dihydroxy-2'-methyl-5'H-pregn-1-eno[17,16-d]oxazole-3,20-dione; II, (11 beta,16 beta)-11,21-dihydroxy-2'-methyl-5'H-pregna-1,4-dieno[17,16-d]oxazole-3,20-dione; III, (6 beta,11 beta,16 beta)-6,11,21-trihydroxy-2'-methyl-5'H-pregna-1,4-dieno[17,16-d]oxazole-3,20-dione; IV, (3 epsilon,11 beta,16 beta)-3,11,21-trihydroxy-2'-methyl-5'H-pregn-5-eno[17,16-d]oxazol-20-one. Metabolites II and III are quantitatively the most important in the urine of the rat, dog, and man; metabolite V, whose structure is uncertain, has been found in human and rat urine. In the formation of metabolites I-V the fused 2-methyloxazoline ring is unmetabolized, whereas the steroid moiety follows the general metabolic pathways reported for other related corticosteroids.

Metabolism of 5-isopropyl-1-methyl-2-nitro-1H-imidazole. Identification of some urinary metabolites in the dog

The metabolism of 5-isopropyl-1-methyl-2-nitro-1H-[2-14C] imidazole in dogs has been investigated after oral administration of 50 mg/kg. Three main metabolites, still containing the nitro group and accounting for about 50% of the total radiocarbon, together with a small amount of the unchanged drug, were isolated from the urine within 48 hr. The structures were determined by mass, infrared, and nuclear magnetic resonance spectroscopy. The biotransformations giving rise to the metabolites isolated involve the isopropyl chain of the molecule, either at the tertiary carbon atom or at one of the two methyl groups, or both. Thus, the metabolic behavior of this 2-nitroimidazole derivative appears to be similar to that previously demonstrated for the class of the isomeric 5-nitroimidazoles.

Studies of binding C3-substitute rifamycins to human and bovine serum albumin

The interactions of a series of C3-substituted rifamycins with human and bovine serum albumins were studied in order to find possible correlations between the degree of binding and the structural features of the various molecules. The results obtained indicate some of the physicochemical properties and, therefore, of the structural requirements which appear to determine or influence the bonding mechanisms of this series of rifamycins. Two types of interaction were found to exist, ionic and hydrophobic types. The findings suggest that the inhibition by protein of the antibacterial activities of these antibiotics depends on the type of bonding mechanism rather than the degree of binding.

Competition between diftalone and other drugs for the binding site(s) on human serum albumin

The influence of a series of drugs on the binding of diftalone to human serum albumin was investigated by equilibrium dialysis. The results indicated that among the different drugs tested phenylbutazone, indomethacin, warfarin and tolbutamide were, in the order listed, the most effective in displacing diftalone from its binding site(s). Additional investigation showed that there was no consistent inhibition by diftalone of warfarin and tolbutamide binding to albumin. The information obtained might prove useful in clinical therapy whenever a combination of drugs is to be administered.