Regeneración de las lesiones críticas del nervio periférico con factores de crecimiento. Estudio experimental / Regeneration of critical injuries of the peripheral nerve with growth factors

Introducción. El objetivo del proyecto es estudiar la regeneración de las lesiones no reparables del nervio periférico, mediante un injerto muscular enriquecido con factores de crecimiento. Material y método. La experimentación se desarrolla en 2 fases: primero, comparamos la sutura directa del defecto crítico en el nervio ciático de 10 ratas, con la interposición de un injerto de músculo autólogo desnaturalizado por calor en otras 10. En la segunda, se comparan 10 ratas con reparación mediante injerto muscular acelular, con la inyección de 2 cc de IGF-1 (10 mg/ml de mecasermina, en solución inyectable) dentro del injerto acelular de otras 10. Realizamos el seguimiento clínico y el control funcional de la marcha, medición de la huella plantar y «Grasping Test». Fueron sacrificadas a los 90-100 días, obteniendo muestras para macro y microscopía, con tinciones de azul de toluidina, hematoxilina-eosina y tricrómico de Masson. Resultados. La primera experimentación demostró el hallazgo de tejido de características nerviosas en las secciones del injerto muscular. La segunda supuso una potenciación de los resultados: mejoría clínica posquirúrgica, precoz deambulación, descenso en la tasa de úlceras por presión en partes acras, recuperación de la huella plantar, e incremento del porcentaje de terminaciones nerviosas en regeneración del cabo distal (47-62%). Conclusiones. Exponemos en este trabajo las posibilidades experimentales y clínicas de la reparación del defecto nervioso mediante músculo desnaturalizado, confirmando la adecuación de la técnica. Además, confirmamos nuestra hipótesis con clínica y determinaciones celulares enriquecidas por la adicción de factores de crecimiento que impulsan la regeneración nerviosa (AU)

Introduction. This project aims to study the regeneration of non-repairable lesions of peripheral nerve by muscle grafts enhanced with growth factors. Material and methods. The experiment was carried out in two phases. The first one compared direct suture of a critical defect in the sciatic nerve of ten rats, with the interposition of autologous muscle graft, denatured by heat, in another ten. The second phase compared ten rats with nerve repair using an acellular muscle graft, with injection of 2 cc of IGF-1 (10 mg/ml mecasermin, Injectable solution) into the acellular graft of another ten. A clinical and functional follow-up was carried out including, ambulation, footprint measurement, and «Grasping Test». The animals were sacrificed at 90-100 days, and samples obtained for macro- and microscopic studies with toluidine blue, haematoxylin-eosin and Masson's trichrome staining. Results. The first experiment showed the characteristic findings of nerve tissue in muscle graft level sections. The second was an enhancement of the results: post-surgical clinical improvement, early ambulation, decrease in the rate of pressure ulcers in toes, recovery of the footprint, and increasing the percentage of nerve endings in distal sciatic regeneration (47-62%). Conclusions. In this study the experimental and clinical possibilities of nerve defect repair by denatured muscle are demonstrated, confirming the suitability of the technique. Furthermore, it confirms our hypothesis with clinical and cellular determinations enriched by the addition of growth factors that promote nerve regeneration (AU)

Using acellular aortic matrix to repair umbilical hernias of calves.

BACKGROUND: Umbilical hernias are a relatively common, possibly hereditary, condition in calves. Acellular aortic matrix (AAM) was evaluated for the repair of umbilical hernias in nine calves. METHODS: Fresh buffalo aorta to be used as a graft was decellularised using 1% sodium dodecyl sulfate and 0.25% trypsin. Under xylazine sedation and local analgesia, the hernial ring was exposed and repaired with the AAM graft using an inlay technique. RESULTS: All animals had an uneventful recovery without clinical signs of wound dehiscence, infection or recurrence of hernias during the 6-month follow-up period. CONCLUSION: AAM of buffalo origin has adequate strength to be used safely for the repair of umbilical hernias in calves.

Transplantation in small animals.

Cell surface proteins which mediate tolerance or rejection of transplanted organs have been well characterized in people. However, despite the relative conservation of the acquired immune response in mammals, for unknown reasons dogs and cats either tolerate transplanted organs more readily or reject them more vigorously. The rejection-associated histologic changes found in human and animal grafts imply that the immune response to graft proteins is not identical amongst species. As a result few tissues or organs are routinely transplanted in client-owned dogs and cats, and larger studies are still needed to characterize chronic changes that may develop. With the continual development of new immunosuppressive drugs and refinement of existing protocols, transplantation options will hopefully increase via the use of xenograft tissues, particularly in dogs.

Transplantation of the uterus in sheep: methodology and early reperfusion events.

AIM: Uterine transplantation is developing into a clinical treatment for uterine factor infertility. An animal model with a similar uterus size and vessels to humans and with pregnancy extending over several months would be beneficial for research on uterine transplantation. The aim of this study was to develop and evaluate autotransplantation of the sheep uterus to an orthotopic position in the pelvis. METHODS: Female sheep (n=7) were subjected to laparotomy with the uterus and its vascular supply and drainage being surgically isolated. The excised uterus was kept ex vivo at +4 degrees C for 60 min and then autotransplanted with vascular end-to-side anastomoses to the external iliac vessels. The effects of uterine blood-reperfusion were assessed by measurements of pCO(2), pO(2), lactate and pH in uterine venous blood. Uterine contractility and histology was assessed after 3 h of reperfusion. RESULTS: Reperfusion of blood was observed in five out of seven transplanted uteri. The pCO(2)/pO(2)-ratio and the lactate level were initially elevated but decreased and became normal after 60 min. After 3 h of reperfusion there was a visible tissue blood flow and spontaneous uterine contractions were seen. Histological analysis revealed a mild inflammation, but no edema or stasis. CONCLUSIONS: This study demonstrates that the sheep uterus can successfully be autotransplanted to an orthotopic position with novel vascular connections. This model is suitable for future experiments studying long-term results concerning uterine viability and pregnancy using a transplanted uterus of similar size to the human uterus.

Evaluation of propofol as an anesthetic in swine tracheal transplant surgery / Evaluación del propofol como anestésico para cerdos sometidosa trasplante de tráquea

Because the swine have been used as an ideal animal model for different medical investigations, it has been useful to the advance in vital organs transplant field. The trachea transplant is a surgical procedure which requires special conditions in anesthetic depth and muscular relax, for a long period, and in addition, an excellent intra and post-operatory analgesic. The aim of this study was to use a combination of xylacine and ketamine, as premedication and evaluate propofol as a general anesthetic in trachea transplant donor or recipient pigs. All the methodology was under the approval of the Committee of Ethics for the Experimentation with Animals of the University of Antioquia. Ten donors and 10 recipients female Yorkshire pigs having a body weight of about 30 kg were used. Trachea extraction from a donor and its transplantation to a recipient in the same surgical procedure was performed. The average body weight (PP) was 30 ± 2.92 kg for both the groups, the average value were as follows: time of recumbency (TR) 8.25 ± 2:85 min; latency period (PL) 6.05 ± 1.73 min, (for both groups); surgical time (TQ) for donors and recipients was 80 ± 0.02, and 247 ± 0.02 min, respectively; heartbeat rate (FC) 90.34 ± 8.14 bpm, O2 saturation (SO2) 95.47 ± 1.79 %; exhaled PCO2 31.13 ± 1.89 mmHg; temperature (T) for both groups was 37.51 ± 0.74oC. The mean arterial pressure average (PAM) for both group was 65.47 ± 5.94 mmHg; the average time of esternal recumbecency (TRE) for donor female pigs was 16.50 ± 4.09 min, and the average time to stand up (TP) for swine recipients was 30.70 + 3.27 min. These results indicate that Propofol can be considered as a safe anesthetic for use in continuous perfusion. Since it has not an analgesic effect it is strongly recommended to combine it with opioids during anesthetic-surgical procedures; it can be also used with neuromuscular preanesthetics or inhaled anesthetics.

Los cerdos se han utilizado como modelo animal ideal para diversas investigaciones médicas; han sido útiles para el avance en el trasplante de órganos. El trasplante de tráquea es un procedimiento quirúrgico que requiere condiciones especiales en profundidad anestésica y relajación muscular por un período largo, y además, una analgesia intra y del postoperatoria excelente. Nuestra investigación utiliza una combinación de xylacine y ketamina, como premedicación y evaluar el propofol como anestésico general en cerdos donantes y receptores en quienes el trasplante de la tráquea sería hecho. Toda la metodología contó con la aprobación del Comité de Ética para la Experimentación con los Animales de la Universidad de Antioquia. Utilizamos 10 donantes y 10 cerdos raza Yorkshire hembras con un peso corporal de cerca de 30 kilogramos. Se realizó la extracción de la tráquea de un donante y el trasplante a un receptor en el mismo procedimiento quirúrgico. El peso corporal (PP) fue de 30 ± 2.92 kg para todo el grupo, el tiempo de recumbencia (TR) para ambos grupos fue de 8.25 ± 2.85 min, el período de latencia (PL) para ambos grupos fue de 6.05 ± 1.73 min, el promedio de tiempo quirúrgico (TQ) para los donantes fue de 80 min ± 0.02, el TQ de los receptores fue de  247m ± 0.02. La presión arterial media (PAM) para todo el grupo fue de 65.47 ± 5.94 mmHg, el promedio de frecuencia cardiaca (FC) para ambos grupos fue de 90.34 ± 8.14 ppm, el promedio de saturación de oxigeno (SO2) fue de 95.47 ± el 1.79% y el CO2 espirado fue de 31.13 ± 1.89 mmHg y el promedio de la temperatura (t) para ambos grupos fue de  37.51 ± 0.74oC. La tiempo de recumbencia esternal (TRE) para las cerdas donantes fue de 16.50 ± 4.09 min y el tiempo para pararse (TP) para los receptores fue de 30.70 ± 3.27 min. El propofol se puede considerar como anestésico seguro para el uso en la perfusión continua durante la anestesia. Puesto que no tiene un efecto analgésico se recomienda combinarlo con opioides.

Controversial aspect of using GFP as a marker for the production of transgenic cattle.

The objective of this study was to examine the feasibility of identification and selection of cattle embryos based on green fluorescence (GFP-positive) in order to obtain calves carrying an integrated transgene. The construct used (pbLGTNF-EGFP) contained the human tumor necrosis factor alpha (hTNFalpha) gene fused to the bovine beta-lactoglobulin promoter (bLG) in plasmid vector pCX-EGFP. In four experiments, 76 zygotes were injected; eight of them developed to the morulae/blastocysts stage of which only five were GFP positive (one of them 100%, one-50%, three- 25%). All of the GFP positive embryos were transferred to recipients. Two calves were born: one after transfer of the 100% GFP positive embryo and the other after transfer of one of the 25% GFP positive embryos. Both animals were healthy with normal weight when compared to two control calves. The integration of pbLGTNF-EGFP in the host genome could not be detected in either of the calves, suggesting that GFP is an unreliable marker for preimplantation screening of embryos.

Screening criteria for feline renal transplant recipients and donors.

Renal transplantation is associated with several potential complications. Early selection and appropriate screening of candidates has reduced the morbidity and mortality associated with this procedure in human beings. In veterinary medicine, the important process of identification and screening of candidates for renal transplantation occurs primarily in private general or specialty practice. This article reviews guidelines for screening of candidates for renal transplantation and related publications in both veterinary and human literature in an attempt to provide comprehensive information to practitioners involved in the selection process. It is anticipated that early referral of stable cats for renal transplantation will further improve the likelihood of a successful outcome.

Cyclosporine and tacrolimus.

Cyclosporine and tacrolimus are potent immunosuppressant agents that have been used extensively in humans, primarily for prevention of transplant rejection but also for the treatment of autoimmune disorders. Both agents have similar mechanisms of action and pharmacokinetic profiles. However, the expected toxicity of the agents is dissimilar. Although cyclosporine usage in veterinary medicine is limited, it has been used enough for therapeutic guidelines to be established. Tacrolimus, however, has undergone limited use in veterinary medicine. The drug is too toxic in dogs for its use to be recommended in most clinical situations. This article reviews the mechanism of action, pharmacokinetics, expected drug interactions and toxicities, and clinical usage of cyclosporine and tacrolimus in veterinary medicine.

Basic principles for reconstruction of problem skin defects on the limbs and feet.

Skin defects on the limbs of animals present a problem from the standpoint that there is not an abundance of skin on the limbs to reconstruct with as there is on the trunk of an animal. Shifting local tissues can be used to correct small limb defects, and skin flaps from the upper limbs or body can be used to correct upper limb defects. Defects on the lower limbs and feet may require distant flaps or free grafts for reconstruction. Foot pads require special attention when being sutured. When foot pads have large defects or are missing there are techniques for replacement: however, there are certain principles that must be abided by when replacing foot pads.

Aspectos funcionais do autotransplante de intestino delgado em substituição ao esôfago cervical: estudo experimental / Functional aspects of small bowel autotransplantation to replace the cervical esophagus: an experimental study

O objetivo deste estudo é analisar o comportamento funcional do autotransplante de intestino delgado em substituição ao esôfago cervical, bem como as repercussões desta intervenção sobre a deglutição e motricidade esofágica no cão.