Characterisation of subchondral bone repair following transplantation of bioreactor-manufactured autologous osteochondral graft in a sheep model.

To date, no single approach to the treatment of osteochondral defects has resulted in satisfactory long-term outcomes, especially in a young and active human population. Emerging innovative tissue engineering strategies, including the use of composite scaffolds, novel cell sources and bioreactors, have shown promising results. However, these techniques need to be validated in translational animal models before they can be implemented in clinical practice. The aim of the present study was to analyse morphological and microarchitectural parameters during subchondral bone repair following transplantation of bioreactor-manufactured autologous osteochondral grafts in a sheep model. Animals were divided into 4 treatment groups: nasal chondrocyte (NC) autologous osteochondral grafts, articular chondrocyte (AC) autologous osteochondral grafts, cell-free scaffolds (CFS) and empty defects (EDs). After 6 weeks, 3 months and 12 months, bone remodelling was assessed by histology and micro-computed tomography (µCT). Although gradual remodelling and subchondral bone repair were seen in all groups across the time points, the best results were observed in the NC group. This was evidenced by the extent of new tissue formation and its best integration into the surrounding tissue in the NC group at all time points. This also suggested that nasal septum chondrocyte-seeded grafts adapted well to the biomechanical conditions of the loaded joint surface.

Lidocaine serum concentration after epidural administration in combination with morphine and fentanyl in rabbit--a preliminary study.

Morphine and fentanyl are often used as adjuvants in epidural anesthesia to prolong analgesia. The aim of this study was to evaluate the impact of addition of morphine or fentanyl to lidocaine on serum lidocaine concentrations in rabbits after epidural administration. During general anesthesia, rabbits of the group L received epidurally 2% lidocaine, rabbits of the group LM 2% lidocaine and morphine, and rabbits of the group LF 2% lidocaine and fentanyl. Blood for determination of serum lidocaine concentration was taken before anesthesia and in first 90 min after epidural administration. After 5, 10, and 25 min in the group L the lidocaine serum concentrations were the lowest, while in the group LM the lidocaine serum concentrations were the highest. Morphine and fentanyl did not cause significant changes of serum lidocaine concentration in rabbits and may be used as adjuvant in epidural anesthesia without significant increase in lidocaine absorption from epidural space.

Ischemic preconditioning decreases laparoscopy induced oxidative stress in the liver.

Experimental studies indicate that oxidative stress during and after laparoscopic surgery may cause liver ischemia-reperfusion injury. The aim of the study was to assess the effect of ischemic preconditioning against liver damage during pneumoperitoneum on oxidative stress. Twenty one New Zealand rabbits were divided into three groups of seven animals. Control group (C) rabbits received anesthesia for 60 min alone; 15 mm Hg intra-abdominal pressure with CO2 for 60 min was used in the pneumoperitoneum group animals (PNP); and 15-min insufflation and 10-min desuflation followed by 60-min pneumoperitoneum were used in the ischemic preconditioning group animals (IP). Venous blood samples were obtained at different time points to measure lipid hydroperoxide, glutathione reductase and total antioxidant status as indicators of increased oxidative stress. Aspartate transaminase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels were evaluated as indicators of hepatocellular injury. The Kruskal-Wallis and Mann-Whitney U tests were used on statistical analysis. Elevated intra-abdominal pressure was found to produce significant increase in lipid hydroperoxide at the end of pneumoperitoneum and 30 min after desuflation in comparison with pre-insufflation period, and with both C and IP groups at the same time points. Total antioxidant status level decreased significantly in the PNP group at 24 h of desuflation. At 24h of desuflation, the AST, ALT and LDH levels were significantly increased in the PNP group in comparison with the levels measured before induction of anesthesia, and with the C and IP groups. Study results demonstrated that ischemic preconditioning prevented hepatocyte injury and oxidative stress during CO2 pneumoperitoneum.

Comparison of the effects of low intra-abdominal pressure and pentoxifylline on oxidative stress during CO2 pneumoperitoneum in rabbits.

BACKGROUND: The aim of this study was to investigate the effect of low-pressure pneumoperitoneum and pentoxifylline, a methylxanthine derivative, in the prevention of injury caused by free oxygen radicals generated during CO(2 )pneumoperitoneum. METHODS: Twenty-eight rabbits were allocated randomly to 4 groups. Control group rabbits (group 1) were subjected to anesthesia for 60 min; group 2 and 3 animals were subjected to a CO(2) pneumoperitoneum (15 or 7 mm Hg); and group 4 rabbits received 50 mg/kg pentoxifylline, followed by a 15-mm-Hg pneumoperitoneum. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), lipid hydroperoxide, glutathione reductase and total antioxidant status were measured. RESULTS: Compared with group 1, a significant increase in lipid hydroperoxide levels at the end of the pneumoperitoneum and 30 min after deflation and a significant decrease in total antioxidant status 24 h after deflation were recorded in group 2. In addition, a significant increase was observed in ALT, AST and LDH levels. These changes were attenuated by low-pressure pneumoperitoneum, whereas pentoxifylline pretreatment appeared to attenuate only transaminase levels. CONCLUSION: Low-pressure pneumoperitoneum could attenuate ischemia/reperfusion injury induced by CO(2 )pneumoperitoneum in a rabbit model whereas pentoxifylline pretreatment appeared to attenuate only transaminase levels. Pentoxifylline did not prevent the development of oxidative stress.

Feline high-rise syndrome: 119 cases (1998-2001).

High-rise syndrome was diagnosed in 119 cats over a 4-year period. 59.6% of cats were younger than one year, and the average height of the fall was four stories. High-rise syndrome was more frequent during the warmer period of the year. 96.5% of the presented cats, survived after the fall. 46.2% of cats had fractured limbs; 38.5% of fractures were of the forelimb, 61.5% of the hindlimb. The tibia was fractured most often (36.4%), followed by the femur (23.6%). 78.6% of femoral fractures were distal. The mean age of patients with femoral fractures was 9.1 months, and with tibial fractures 29.2 months. Thoracic trauma was diagnosed in 33.6% of cats. Pneumothorax was diagnosed in 20% of cats, and pulmonary contusions in 13.4%. Falls from the seventh or higher stories, are associated with more severe injuries and with a higher incidence of thoracic trauma.

Aminotransferases after experimental pneumoperitoneum in dogs.

BACKGROUND: Laparoscopic surgery has rapidly become a popular and widely used technique. Elevated intra abdominal pressure due to gas insufflation for laparoscopic surgery may result in a number of local and systemic effects on the organism. The effects of pneumoperitoneum on the cardiovascular and respiratory system are well known today, but very few studies have been carried out on the consequences of pneumoperitoneum on hepatic integrity. The aim of the present study was to assess changes in aminotransferases, bilirubin and prothrombin time after pneumoperitoneum in dogs. METHODS: The effects of different levels and duration of intra abdominal pressure and different gases on liver function test were investigated in dogs. The levels of aspartate aminotransferase, alanine aminotransferase, total and direct bilirubin, and prothrombin time, according to the duration and the level of pneumoperitoneum and gas, were measured at 6, 12, 24 and 48 h of desufflation. RESULTS: The levels of total bilirubin, direct bilirubin and prothrombin time showed no significant alteration. A statistically significant (P < 0.01) elevation of aspartate aminotransferase and alanine aminotransferase was recorded in the group of animals with higher intra abdominal pressure and longer duration of pneumoperitoneum. They returned to normal values within 48 h. CONCLUSION: Transient elevation of hepatic transaminases occurred after laparoscopic surgery, but they returned to normal values within 48 h. These increases were more prominent with higher and longer intra abdominal pressures irrespective of the type of insufflated gas. Alteration in aminotransferases was not associated with any clinical signs of hepatic dysfunction in experimental animals.