Temporomandibular joint arthrocentesis in a rabbit model: technique and recommendations in the study of temporomandibular disorders.

INTRODUCTION: Arthrocentesis has been used in the temporomandibular joint (TMJ) to analyze components of the synovial fluid or as a therapeutic procedure associated or not with the administration of a drug. The rabbit is one of the most commonly used animal species as a model for pathologies that affect the TMJ. The aim of this study was to propose a specific technique to perform arthrocentesis on the rabbit TMJ, emphasizing descriptions of reference points and measurements for a successful puncture without complications. MATERIALS AND METHODS: Fourteen adult rabbits (Oryctolagus cuniculus) were used. The project was approved by the Scientific Ethics Committee of the Universidad de La Frontera (File Nº083/2016). RESULTS: The description of the technique was divided into three steps: 1) Location of the rabbit TMJ, 2) Positioning of the needles in the TMJ, and 3) Passage of fluid through the TMJ. CONCLUSIONS: This arthrocentesis technique could help to simplify the procedure and give the investigator a guide for joint washing and extraction of synovial fluid in the rabbit TMJ.

Injection in temporomandibular joint of rats. Description of technical protocol.

The development of animal models for research has been very diffused. Osteoarthritis is a joint degenerative pathology that induces cartilage erosion, chondrocyte proliferation and osteophyte formation. The aim of this paper is to present a technical procedure to perform the injection of monosodium iodine acetate in the temporomandibular joints of rats to generate osteoarthritis and to contribute to future research analysis related to pathology progression and proper treatment performance. The use of rat models may be a complex process because of their size, but they can be compared to the human temporomandibular joint due to the similar characteristics and the possibility of performing diagnosis and treatment protocols in order to detect this pathology.

Comparación entre etil-cianoacrilato y sutura convencional en el cierre de incisiones de piel de conejo (Oryctolagus cuniculus) / Comparison between ethyl-cyanoacrylate and conventional suture for the closure of skin incisions in rabbit (Oryctolagus cuniculus)

Las ventajas de los adhesivos en base a cianoacrilatos para uso en cierre de heridas cutáneas ha sido demostrada, pero escasos estudios reportan el uso del etil-cianoacrilato a nivel nacional. El objetivo fue comparar aspectos morfológicos de cicatrización en piel de conejo entre etil-cianoacrilato y sutura. Utilizamos 10 conejos machos adultos, divididos en 2 grupos de 5 animales, del Centro de Cirugía Experimental de la Universidad de La Frontera, Chile. Al grupo experimental se le realizaron dos incisiones, una en cada lado del dorso del tórax, 4 cm de largo, atravesando epidermis y dermis. La incisión derecha fue cerrada con etil-cianoacrilato, la izquierda con punto intradérmico de ácido poliglicólico. Se tomaron biopsias a los días 7, 14 y 21 días postoperatorio. Al día 7, la incisión tratada con etil-cianoacrilato presentó una reacción inflamatoria moderada, con infiltración moderada de PMN. Las biopsias de sutura presentaban una etapa de regeneración más avanzada, sin presentar desarrollo epidérmico. Al día 14, las incisiones tratadas con etil-cianoacrilato se encontraban en la fase final de la etapa inflamatoria, mientras que las biopsias de sutura se encontraban ya en etapa proliferativa. Al día 21, ambos tipos de cierre se encontraban en etapa de remodelación, con epidermis gruesa y lámina basal formada. La dermis presentó tejido conectivo denso irregular, escasos folículos pilosos y glándulas sebáceas. El etil-cianoacrilato, como adherente cutáneo, es una buena alternativa de uso, mostrando una adecuada biocompatibilidad. Presentando una reacción inflamatoria moderada, limitada y de corta duración a nivel dérmico. La cicatriz logra mejores resultados estéticos con respecto a las incisiones cerradas con sutura. Se debe considerar su uso limitado a sitios no expuestos a movimientos y de baja tensión...

The advantages of cyanoacrylate based adhesives for use in cutaneous wound closure has been demonstrated, but few studies reporting the use of ethyl cyanoacrylate nationwide. The objective was to compare morphological aspects of healing in rabbit skin between ethyl-cyanoacrylate and suture. We used 10 adult male rabbits divided into 2 groups of 5 animals, the Center for Experimental Surgery, Universidad de La Frontera, Chile. The experimental group was subject to two incisions, one at each side of the dorsum of the thorax, 4 cm long, spanning epidermis and dermis. The incision was closed with ethyl right-cyanoacrylate, intradermal left with point of polyglycolic acid. Biopsies were taken at days 7, 14 and 21 days postoperatively. At day 7, the incision treated with ethyl cyanoacrylate presented a mild inflammatory reaction with moderate infiltration of PMNs. Suture biopsies showed a more advanced stage of regeneration, without presenting epidermal development. At day 14, the incisions treated with ethyl cyanoacrylate were in the final phase of the inflammatory stage, while suture biopsies were already in proliferative stage. At day 21, closing both types were remodeling stage, with thicker epidermis and basal lamina formed. The dermis showed irregular dense connective tissue, poor hair follicles and sebaceous glands. Ethyl-cyanoacrylate as Skin Adhesive is a good alternative use, showing adequate biocompatibility. Featuring a moderate inflammatory reaction, limited and of short duration dermal level. The scar achieves better cosmetic results regarding the incisions closed with sutures. Consideration should be limited to use low-tension sites not exposed to movements...

Novel resistance to imipenem associated with an altered PBP-4 in a Pseudomonas aeruginosa clinical isolate.

A Pseudomonas aeruginosa (isolate 416) from a patient with pneumonia, was initially susceptible to imipenem (MIC: 2 mg/l) but became resistant to this antibiotic (isolate 470, MIC: 32 mg/l) during imipenem therapy. Treatment failed. No parallel increases in MIC were observed for other antimicrobials tested. Isolates 416 and 470 shared the same pyocin type and serotype, produced small amounts of an inducible beta-lactamase, and had similar lipopolysaccharide compositions. On electrophoresis of outer membrane proteins, the porin F, identified by the monoclonal antibody MA4-4, was expressed similarly by the two isolates but the production of one band (apparent molecular weight: 47,000) was diminished in isolate 470. [14C]-Imipenem labelling of intact cells proceeded more slowly in 470 than in 416, especially when bacterial cells were treated by antibody MA4-4 to block the porin F channel. [14C]-Imipenem labelling of penicillin binding proteins (PBP) showed that the band identified as PBP-4 bound markedly less radioactivity in isolate 470 than in 416. After isolate 470 was passaged several times in antibiotic-free broth, the imipenem MIC was decreased from 32 to 8 mg/l, and the [14C]-imipenem PBP pattern recovered the initial profile as exhibited by isolate 416. Two resistance mechanisms, affecting imipenem electively, could have combined their effect in the post-therapy isolate, altered target protein and reduced permeability.