Correspondence between the time course of cerebral vasospasm and the level of cerebral dopamine-beta-hydroxylase in rabbits.

The aim of the study was to explore whether the biphasic time course of the vasospastic response following experimental subarachnoid hemorrhage is associated with any concomitant changes in the amount of cerebral dopamine beta-hydroxylase in the noradrenergic central nervous system. A single-hemorrhage animal model was used. Rabbits were sacrificed from day 1 to day 8 after subarachnoid hemorrhage. Intimal corrugation of the basilar artery and the amount of cerebral dopamine beta-hydroxylase in the hypothalamus and brain stem were measured each day. Vasospastic changes occurred in the biphasic manner following subarachnoid hemorrhage. More profound vasospastic corrugation occurred in the acute phase, followed by a slightly less intense corrugation in the chronic phase (between days 5 and 8 after the subarachnoid hemorrhage). Simultaneously, a clear concomitant biphasic time course developed in the form of an increased amount of dopamine-beta-hydroxylase in the noradrenergic nervous system of the rabbit hypothalamus and brain stem during the acute and chronic phases after the subarachnoid hemorrhage. Statistically significant correlation between basilar artery corrugation and the amount of dopamine beta-hydroxylase was found. These results suggest the possible role of the central sympathetic system in the pathogenesis of vasospasm. At the same time, this study demonstrates the chronological similarity of the vasospastic development after subarachnoid hemorrhage in the animal experimental model with the human time course of vasospasm.

Abscess formation within cerebellar metastatic carcinoma--report of two cases and review of the literature.

BACKGROUND: The occurrence of an abscess in conjunction with a tumor in the brain is very rare. Only presumptions exist about their origin and manner of dissemination. Preoperative discrimination between a brain tumor with cystic degeneration and a brain abscess within a tumor may be difficult or even impossible. The purpose of this report is to demonstrate the difficulty of such discrimination using conventional CT diagnostics alone. METHODS: Two patients with abscess formation in association with metastatic carcinoma in the cerebellum are presented and compared with similar cases in the literature. The etiology and the route of dissemination are discussed. RESULTS: In our first patient with previously diagnosed lung carcinoma and a CT showing suspected cerebellar metastasis only, an abscess caused by Propionibacterium acnes was found in the cerebellum and treated surgically. No tumor was recognised during the operation. Post-mortem examination six weeks later revealed the coexistence of remnants of a chronic abscess as well as metastatic lung carcinoma at the operation site. The second patient presented with an enhanced, ring-like cystic cerebellar lesion. During surgery, a purulent exudate with a coagulase-negative type of Staphylococcus species was found within the metastatic carcinoma of unknown origin. Both were radically excised and the patient recovered well. Neither patient had a history of previous infection and the pathway for abscess formation in both patients remained unclear. About 30 cases of abscesses associated with intracranial neoplasms were found in the literature. Including our own report, only three cases of abscesses within metastatic carcinoma have been published. CONCLUSIONS: Modern diagnostic tools reported to differentiate more reliably between an abscess and a tumor are diffusion-weighted MR and proton MR spectroscopy techniques. Brain imaging using CT alone may not reliably demonstrate both coexisting lesions or differentiate between them. It is important to know that a metastatic brain lesion can occur in association with a brain abscess and that tissue sampling for pathological as well as microbiological testing is of crucial importance for optimal therapy for both lesions.

Recurrent giant invasive thoracolumbar schwannoma.

Giant invasive spinal schwannoma is a new term proposed by Sridhar in 2001 for a particularly aggressive type of benign spinal schwannoma. Only a few cases have been published, the majority of these located in the lumbosacral spine, two in the thoracic and only one in the cervical spine. A rare case of such a tumor is presented. The tumor predominantly occupied level L1 and partially levels T12 and L2, and recurred 13 years after the first seemingly radical excision of a benign melanotic schwannoma. The highly vascularized tumor was radically excised using the dorsal approach, and a Sokon transpeduncular fixation was performed. Carter's lateral thoraco-abdominal access allowed the retroperitoneal and intravertebral expansions of the tumor to be removed and L1 corpectomy to be accomplished. Ventral vertebral stabilization was achieved with a titanium cage. After the operation, the pain in the patient's left leg subsided. Three years after the management, he is still pain-free, able to walk freely and to resume his usual daily activities.

Abdominal actinomycosis presenting as a small-bowel obstruction.

A 48-year-old female, presented as a case of acute abdomen with a small-bowel obstruction and a palpable hypogastric mass, was urgently operated. Laparotomy revealed a tumor mass of unknown origin that included a loop of the small bowel by compressing it. Resection of the tumor including a portion of the large and small bowel was performed, and pathohistological examination revealed actinomycosis. The cause of abdominal actinomycosis in this patient could be the implantation of an intrauterine device nine years prior to the operation.

The influence of noradrenergic blockade on vasospasm and the quantity of cerebral dopamine beta-hydroxylase following subarachnoid haemorrhage in rabbits.

BACKGROUND: The aim of this study of experimental subarachnoid haemorrhage (SAH) and exclusion of the sympathetic nervous system (SNS) in rabbits was to find out if changes in the central noradrenergic areas of the hypothalamus and brain stem could be ascertained, in parallel with measurement of the intensity of chronic cerebral vasospasm in the basilar arteries. METHODS: Histologic specimens were prepared by perfusion fixation on day 8 after the SAH. The spastic effect of experimentally induced SAH in New Zealand rabbits was investigated: firstly, using our previously developed method for measuring the corrugation coefficient (CC) of the vessel intima on precisely defined locations of the basilar artery (BA) with the aid of computer image analysis; and secondly, by immunohistochemical assessment of the concentration and localization of dopamine beta-hydroxylase (DBH), using anti-DBH, at precisely defined sites of the hypothalamus and brain stem of the same rabbit. RESULTS: The intima of the BA, assessed by CC, was significantly less corrugated and had significantly less DBH in group A (the control group without SAH and without additional interventions; mean CC = 1.192, P = 0.004; median DBH = 0.50, P = 0.044), in group C (SAH and alpha-blocker phenoxybenzamine; mean CC = 1.142, P = 0.000; median DBH = 0.75, P = 0.001), and in group D (SAH and cervical gangliectomy; mean CC = 1.210, P = 0.003; median DBH = 0.50, P = 0.002) compared with group B (rabbits with SAH and without medication). Group B showed a significantly more intensive accumulation of DBH (median DBH = 1.15) and, according to the CC (mean CC = 1.369), more intensive corrugation of the intima of BA than all other groups. The correlation between CC and DBH for all the rabbits (groups A, B, C and D together) was significantly positive (Spearman Rho = 0.470; p = 0.010). CONCLUSIONS: The results of this study demonstrated: firstly, an intensive excitatory influence of SAH on the quantity of DBH in central noradrenergic areas in the hypothalamus and brain stem; secondly, a very effective influence of peripheral and systemic sympathetic exclusion on lowering the quantity of central sympathetic DBH; thirdly, that the changes in the BA of individual rabbits occur simultaneously with corresponding changes in DBH-containing neurons, thus suggesting the likelihood of SNS involvement in the pathogenesis of post-SAH vasospasm in rabbits.

Attenuation of cerebral vasospasm in rabbits using clonidine hydrochloride, a central adrenergic agonist.

The aim of this study was to assess, firstly, if exclusion of central noradrenergic areas in the hypothalamus and brain stem with the central sympathetic blocker clonidine hydrochloride could prevent the development of chronic vasospasm following experimental subarachnoid haemorrhage in rabbits and, secondly, if, parallel with the effect on cerebral arteries, changes in dopamine beta-hydroxylase concentration in the hypothalamus and brain stem could also be detected. Experimental subarachnoid haemorrhage, in concentrations of 1 ml of autologous arterial blood/1 kg of body weight was carried out on 18 New Zealand rabbits. Histological specimens were obtained by the method of perfusion fixation after the rabbits were sacrificed on day 8 after subarachnoid haemorrhage. The spastic effect of experimentally induced subarachnoid haemorrhage was determined by assessing the intensity of corrugation of the intima of the rabbit basilar artery by the previously developed method of corrugation coefficient and computer image analysis. The concentration and localization of dopamine beta-hydroxylase in noradrenaline-containing neurons was immunohistochemically assessed (semiquantitatively as 0, 1 and 2) with anti-dopamine beta-hydroxylase, at precisely defined sites of the hypothalamus and brain stem of the same rabbit. The results revealed less corrugated and smoother intima in the basilar artery and significantly lower dopamine beta-hydroxylase concentration in the control group of rabbits with sham subarachnoid haemorrhage and without any additional interventions (mean corrugation coefficient=1.123+/-0.024, P=0.35 x 10(-3); mean dopamine beta-hydroxylase=0.350+/-0.071, P=0.22 x 10(-3)), and smoother intima in the basilar artery with significantly lower concentration of dopamine beta-hydroxylase in the clonidine group (rabbits with subarachnoid haemorrhage and central alpha(2)-blocker clonidine hydrochloride at a daily dose of 0.03 mg/kg of body weight for 8 days; mean corrugation coefficient=1.177+/-0.058, P=1.7 x 10(-3); mean dopamine beta-hydroxylase=0.583+/-0.175, P=1.1 x 10(-3)). In comparison, the haemorrhage only group (rabbits with subarachnoid haemorrhage and without medication; mean corrugation coefficient=1.370+/-0.101; mean dopamine beta-hydroxylase=1.214+/-0.313) displayed intensive corrugation of the intima of the basilar artery and a significantly more intensive accumulation of dopamine beta-hydroxylase than did the control group and the clonidine group. The results of this study demonstrated that the central alpha(2)-blocker clonidine hydrochloride effectively prevents vasospasm, and diminishes the concentration of cerebral dopamine beta-hydroxylase in the hypothalamus and brain stem after experimental subarachnoid haemorrhage in rabbits.