Effect of local use of L-carnitine after myringotomy on myringosclerosis development in rats.

OBJECTIVES: This study aimed to investigate the effect of local and intraperitoneal administration of L-carnitine on the prevention of experimentally induced myringosclerosis, and to compare treatment efficiency. METHODS: Twenty-four Albino-Wistar rats (48 ears) were bilaterally myringotomised and divided randomly into four groups: group one received no treatment, group two received intraperitoneal L-carnitine, group three received local L-carnitine, and group four received both intraperitoneal and local L-carnitine. On the 15th day after treatment, tympanic membranes were harvested and evaluated histopathologically for myringosclerotic plaque formation, fibroblastic proliferation, tympanic membrane thickness and new vessel formation. RESULTS: The group one tympanic membranes showed extensive thickness, and the incidence of myringosclerosis and fibroblast proliferation were greater than in groups two and four. There were statistically significant differences in tympanic membrane thickness between groups three and four, and in myringosclerosis incidence and fibroblast proliferation, comparing groups two, three and four. CONCLUSION: Myringosclerosis development was significantly reduced in rats receiving myringotomy plus intraperitoneal L-carnitine. Intraperitoneal L-carnitine administration prevented fibroblastic proliferation and tympanic membrane thickening (both of which cause further tympanic membrane destruction), thus reducing myringotomy-associated morbidity. Local L-carnitine administration had limited effectiveness in this experimental setting.

Protective effects of vitamins E, B and C and L-carnitine in the prevention of cisplatin-induced ototoxicity in rats.

OBJECTIVE: This experimental study aimed to investigate the effects of vitamins E, B and C and L-carnitine in preventing cisplatin-induced ototoxicity. METHODS: Twenty-five adult, male, Wistar albino rats were randomly allocated to receive intraperitoneal cisplatin either alone or preceded by vitamins B, E or C or L-carnitine. Auditory brainstem response (i.e. hearing thresholds and wave I-IV intervals) and distortion product otoacoustic emissions (i.e. signal-to-noise ratios) were recorded before and 72 hours after cisplatin administration. RESULTS: The following statistically significant differences were seen: control group pre- vs post-treatment wave I-IV interval values (p < 0.05); control vs vitamin E and B groups' I-IV interval values (p < 0.05); control vs other groups' hearing thresholds; vitamin E vs vitamin B and C and L-carnitine groups' hearing thresholds (p < 0.05); and vitamin B vs vitamin C and L-carnitine groups' hearing thresholds (p < 0.05). Statistically significant decreases were seen when comparing the initial and final signal-to-noise ratios in the control, vitamin B and L-carnitine groups (2000 and 3000 Hz; p < 0.01), and the initial and final signal-to-noise ratios in the control group (at 4000 Hz; p < 0.01). CONCLUSION: Vitamins B, E and C and L-carnitine appear to reduce cisplatin-induced ototoxicity in rats. The use of such additional treatments to decrease cisplatin-induced ototoxicity in humans is still under discussion.

Leflunomide prevents vasospasm secondary to subarachnoid haemorrhage.

BACKGROUND: Though cerebral vasospasm is one of the most serious complications of subarachnoid haemorrhage (SAH), its complex pathogenesis is poorly understood and available clinical treatment options are unsatisfactory. This study was designed to examine the efficacy of leflunomide, an immunomodulatory agent with inhibitory properties, on vascular smooth muscle cell proliferation and inflammation in a rabbit cerebral vasospasm model. METHODS: Twenty-two adult New-Zealand rabbits were assigned to 4 groups: control, SAH, SAH plus vehicle, SAH plus leflunomide. Subarachnoid haemorrhage was induced by administration of 1 ml of fresh unheparinised autologous arterial blood into the cisterna magna. Oral leflunomide (2 mg/kg) or vehicle treatment was started 12 h after the induction of subarachnoid haemorrhage and administered once a day. Three days later, the animals were sacrificed and the basilar artery was examined histologically for the lumen area and the thickness of the vessel wall. Inflammatory reaction was also examined by counting white blood cells within the vessel wall by means of light microscopic examination using haematoxylin and eosin staining. FINDINGS: Severe and moderate vasospasms were detected in the basilar artery of the SAH and SAH plus vehicle treated groups, respectively. Leflunomide effectively reduced the vasospasm of the basilar artery. Compared to the vehicle treated group, leflunomide significantly reduced the lumen area (p < 0.01) and hyperplasia of the vessel wall (p < 0.01). Although inflammatory response within the vessel wall was reduced in the leflunomide treated group, no statistical significance was found between groups (p = 0.07). CONCLUSION: This study demonstrates for the first time that leflunomide treatment attenuates cerebral vasospasm in a rabbit SAH model while inflammatory reaction in the vessel wall is not affected. Although further studies are needed to reveal its molecular mechanisms in relieving vasospasm, leflunomide may provide a therapeutic potential for human cerebral vasospasm induced by SAH.

Ventricular ependymoma in a German Shepherd dog.

Using magnetic resonance imaging (MRI) together with clinical, pathomorphological and immunohistological methods, a ependymoma is described in a 9-year-old German Shepherd dog, which presented with behavioural and oculocephalic responses and generalised ataxia. The ependymoma, 9 x 6 x 5mm in size, was localised intra-axially in the right interventricular foramen and hydrocephalus was observed by MRI. Microscopically, the tumour was composed of pseudorosettes, and immunohistochemical examination revealed vimentin and glial fibrillary acidic protein immunoreactivity in the neoplastic cells.

Ventral fixation in atlantoaxial instability with axial fracture in a dog.

This study reports the diagnosis and the surgical management of atlanto-axial instability with an oblique axial fracture in a dog. The fracture was diagnosed by radiography and Computed Tomography (CT). In the CT views, the appearance of the distortion of the atlantoaxial articular surface was interpreted as instability. The stabilization was achieved with the cancellous screws. Following the surgery, the neurological status improved and the dog no longer had marked neurological deficits.

Management of spinal trauma in 69 cats.

This study sought to evaluate a series of clinical and radiological findings on spinal trauma in cats and the outcome that emerged from conservative or surgical treatment using 2 types of spinal stapling: stabilization using a Steinmann pin and coated polypropylene. Case records were reviewed for their diagnostic approaches on the basis of physical and neurological conditions, and concurrent disorders in addition to spinal trauma. Radiological examinations of the vertebral column were carried out using survey radiography, myelography and epidurography. All cases were classified according to etiopathogenesis of the disease. Surgical treatment consisted of decompression (laminectomy, hemilaminectomy and durotomy), or decompression with stabilization which was performed by one of two methods. The first one was the employment of translaminar stapling at the base of a spinous process and the other involved spinal stapling at the spinous process. The spinal lesions were identified as cervical (n = 2), thoracic (n = 35), lumbar (n = 22), sacral and caudal (n = 10). While 19 out of 30 conservatively managed cases recovered, the rest had persistent residual paresis and ataxia. Complete recovery was seen in 4 cats that underwent hemilaminectomy and 3 subjected to laminectomy. Partial recovery was observed in 5 cases involving laminectomy; however, there was no improvement observed in another 2 cases. Each animal was followed for at least a 3-month period to evaluate the clinical assessment of the results following treatment. The results of conservative and operative management of spinal trauma indicated that the type and degree of spinal cord degradation strongly influenced any prognosis. The results emerging from decompressive procedures seemed satisfactory for those cases where instability was not an issue. Both stabilization techniques were not ideal in terms of their methodological versatility or regarding weaknesses of bone structure observed in intra- and postoperative periods. However, translaminar stapling at the base of a spinous process was deemed to be the superior technique.

Failure of ureteral replacement with Gore-Tex tube grafts.

OBJECTIVES: To evaluate the role of polytetrafluoroethylene (Gore-Tex) as a ureteral substitute in dogs after resection of a 5 to 8-cm-long middle segment. METHODS: Five mongrel dogs underwent resection of the middle segment of the left ureter and segmental replacement of the resected part with segments of Gore-Tex over a double-J catheter. The double-J stents were removed at 21 days and the dogs were evaluated by excretory urography and abdominal ultrasonography 12 weeks after surgery. They were then killed and the ureters and the kidneys examined both grossly and microscopically. RESULTS: There was radiologic evidence of advanced hydronephrosis on the left side in all 5 dogs. Grossly, the left kidneys showed marked pelvic and proximal ureteral dilatation and atrophy of parenchyma. Severe stricture at the anastomotic sites and marked fibrous tissue around the prostheses were found. No cellular lining was found in the Gore-Tex lumen. CONCLUSIONS: There is no potential for ureteral replacement by Gore-Tex tube graft.