Short-Term Effects of Deliberate Subparaneural or Subepineural Injections With Saline Solution or Bupivacaine 0.75% in the Sciatic Nerve of Rabbits.

Background: Ultrasound (US)-guided techniques for peripheral nerve blockade have revealed that intraneural injections are relatively frequent and not necessarily associated with neurological deficits. Objectives: To evaluate the short-term effects of deliberate injections performed under direct vision in two different sites of the sciatic nerve (ScN). Material and Methods: Seventy-two New Zealand white rabbits randomly assigned to one of four experimental groups (n = 18) were employed. All procedures were conducted at a proximal femoral level where the ScN incorporates the common peroneal nerve and the tibial nerve (TN). Fixed volumes of 0.5 ml of saline solution (ES group) or bupivacaine 0.75% (EB group) were administered extrafascicularly inside the paraneurium of the ScN or intrafascicularly (IS and IB groups) under the epineurium of the TN. Cross-sectional area (CSA) and relative echogenicity (RE) of the entire ScN were determined by US before injections, after injections, and at 3 and 7 days. ScN samples were obtained for structural and ultrastructural histopathological studies. Proprioceptive, sensorial, and motor function were clinically evaluated on a daily basis. Results: The CSA of the ScN increased significantly immediately after injections when compared with pre-injection values in all groups (p < 0.05). The RE of the ScN decreased in relation to pre-injection values in all groups (p < 0.05). The CSA and RE of the ScN returned to normal values 7 days after injections in almost all groups. Injected nerves showed histological signs of mild perineural inflammation. Histopathological scores were not significantly different between groups (p > 0.05). The architecture of the ScN was preserved in all rabbits at 3 days and in 31/32 rabbits at 7 days. A focal area of damaged nerve fibers with degeneration of the axons and myelin sheath affecting the TN was observed in one rabbit of the IB group. Nerve function was not clinically impaired in any case. Conclusion: Despite the lack of severe nerve disruption observed in most rabbits, the evidence of a focal area of damaged nerve fibers in one rabbit injected intrafascicularly with bupivacaine confirms that intrafascicular injections should be avoided as they may increase the risk of nerve damage.

IMAGING DIAGNOSIS-RADIOGRAPHIC, ULTRASONOGRAPHIC, AND COMPUTED TOMOGRAPHIC CHARACTERISTICS OF A DUODENAL DUPLICATION CYST IN A YOUNG CAT.

A 7-month-old, 2.8 kg, intact female Siamese cat was evaluated for repetitive and intermittent episodes of vomiting and anorexia. Abdominal palpation revealed a round, firm, nonpainful mass in the right cranial abdomen. Ultrasonography findings were consistent with a cystic structure adjacent to the descending duodenum. The structure exhibited a "muscular rim sign." A duodenal duplication cyst was confirmed by histopathological analysis. Computed tomography ruled out concurrent vertebral anomalies and clarified anatomic relationships for surgical planning. To the authors' knowledge, this is the first description of an ultrasound "muscular rim sign" in a duodenal duplication cyst in a cat.

Ultrasound-guided administration of lidocaine into the sciatic nerve in a porcine model: correlation between the ultrasonographic evolution of the lesions, locomotor function and histological findings.

Intraneural puncture of local anaesthetics has been associated with permanent or transitory nerve injury. The use of ultrasound (US)-guided techniques for the blockade of peripheral nerves has revealed that intraneural puncture is a relatively common complication, which is not frequently associated with neurological deficits. In this study, 2.5 mL of lidocaine were administered using US-guidance into the sciatic nerve (ScN) of 12 piglets. The punctured nerves were sequentially evaluated by US (cross sectional area and relative echogenicity) before and immediately after the injections, and then at 1, 2, 4, 7 and 14 days. At these times, animals were euthanased two by two at each time point, and ScN samples were removed for histological examination. Cross sectional area and relative echogenicity values were statistically different immediately after the injections, returning to pre-puncture values within 4 days. The inflammatory process observed by histopathology showed a similar trend indicating that the integrity of the perineurium was maintained. Locomotor deficits were not observed. The increase in size of the ScN produced by the injection of lidocaine intraneurally did not induce motor deficits in piglets in the current study.

Imaging diagnosis-infiltrative lipoma causing spinal cord and lumbar nerve root compression in a dog.

A 12-year-old, male, fox terrier dog presented with an abnormal gait of the left pelvic limb. Computed tomography revealed a large, homogeneous, hypoattenuating, noncontrast enhancing mass within the left epaxial muscles that invaded the L5-6 vertebral canal and caused spinal cord compression. Imaging findings were consistent with an infiltrative lipoma. The mass was removed and a left hemilaminectomy was performed in the affected area. Histopathology confirmed the mass to be an infiltrative lipoma. The dog recovered and regained neurologic function within 2 weeks. Computed tomography assisted preoperative planning by characterizing the shape, size, and location of the mass.

In vitro response to Candida albicans in cultures of whole human blood from young and aged donors.

Invasive infections with opportunistic fungi, such as Candida albicans, have become an increasing problem in aged adults in recent years. This work investigates the influence of human ageing on C. albicans recognition by toll-like receptors (TLRs), essential components of the innate immune system, using a cohort of 96 young (15-42 years) and aged (>70 years) human volunteers. No significant differences between aged and young donors were observed on (1) cell surface TLR2, TLR6 and TLR4 expression on lymphocytes, monocytes and granulocytes, (2) production of cytokines [IL-8, IL-1beta, IL-6, IL-10, tumour necrosis factor (TNF)-alpha and IL-12p70] and prostaglandin E(2) (PGE(2)) by whole human blood in response to C. albicans and (3) fungicidal activity of whole blood. A statistically significant higher titre of natural anti-C. albicans antibodies was found in plasma of volunteers between 80 and 95 years old when compared with other age groups, probably as a consequence of the increased levels of serum Ig that has been described in elderly subjects. Therefore, the results indicate that the increased susceptibility to C. albicans infections in the elderly is not a consequence of defects in TLRs expression or signalling, nor of an impaired fungicidal activity of blood.

Ultrasonographic, computed tomographic and magnetic resonance imaging anatomy of the normal canine stifle joint.

Ultrasonographic (US), magnetic resonance (MR) and computed tomographic (CT) images of normal canine stifle joints were obtained and compared with plastinated cross-sectional slices of cadaver specimens from the same dogs. The bony and articular structures were identified and correlated with the three diagnostic imaging modalities. These results provide an atlas of normal cross-sectional US, MR and CT anatomy of the canine stifle, which can be used for the interpretation of stifle images from any of these imaging modalities.

The Komesaroff anaesthetic machine for delivering sevoflurane to dogs.

Objective To quantify the vapour output of the Komesaroff machine when using sevoflurane and to determine its performance for inducing and maintaining sevoflurane anaesthesia in dogs. Study design Prospective experimental study. Animals Six clinically normal beagles, aged 3-6 years and weighing 20 ± 1.65 kg (mean ± SEM). Methods The first study was performed using five Komesaroff vaporizers to measure the sevoflurane concentration delivered at each tap setting (I to IV) at 5, 10, 15, 20, 25, 30 and 35 minutes. For this study a ventilator was connected to the Komesaroff machine and set to deliver a tidal volume of 250 mL at 10 cycles minute-1; oxygen flow was 100 mL minute-1. A three-litre reservoir bag was attached to the Y-piece connector to act as a lung model. In the second study anaesthesia was induced in dogs with sevoflurane delivered by face-mask mask and carried in 2 L minute-1 100% oxygen and with the vaporizer set at the fully open position. The quality and speed of induction were recorded. After orotracheal intubation, anaesthesia was maintained for 60 minutes with sevoflurane using an oxygen flow of 100 mL minute-1. The dogs were allowed to breathe spontaneously. The respiratory rate (RR), heart rate (HR), oesophageal temperature, systolic (SAP) mean (MAP) and diastolic (DAP) arterial pressure, end-tidal CO2 concentration (Fe'CO2) end-tidal (Fe'SEVO) and peak-inspired (FiSEVO) percentages of sevoflurane, and vaporizer tap setting were recorded every 5 minutes during anaesthesia. Results The delivery of sevoflurane was constant for each vaporizer setting. The mean output of sevoflurane was 0.44 ± 0.01% for setting I, 2.59 ± 0.18% for setting II, 3.28 ± 0.22% for setting III and 3.1 ± 0.5% for setting IV. In the second study, the mean induction time was 7.72 ± 0.60 minutes and the quality of the induction was good in all dogs. The mean vaporizer tap setting for the maintenance of anaesthesia was 3.48 ± 0.12 and the mean values for Fe'SEVO and FiSEVO were 2.42 ± 0.04% and 2.87 ± 0.06%, respectively. The pedal withdrawal reflex persisted throughout anaesthesia. Conclusions It proved impossible to produce surgical anaesthesia with sevoflurane delivered by the Komesaroff machine despite the highest possible sevoflurane concentration being delivered. Clinical relevance Sevoflurane delivered from the Komesaroff machine cannot be relied upon to maintain surgical anaesthesia in spontaneously breathing dogs.