Carotid endarterectomy without protective measures in patients with occluded and non occluded contralateral carotid artery.

BACKGROUND: Comparison of carotid endarterectomy in patients with and without occluded contralateral carotid artery. DESIGN: evaluation of results without using shunt or patch. SETTING: <> Hospital, Medical School, University of Athens. SUBJECTS: 235 patients, divided into group I of 40 patients with and group II of 195 patients without occluded contralateral carotid artery. INTERVENTION: carotid endarterectomy under general anesthesia. MAIN OUTCOME MEASURES: heparin administration, stable hemodynamic status during clamping, short duration monitoring postoperatively. RESULTS: Postoperative morbidity of both groups was 2.5% (6/235) and mortality 1.7% (4/235). Group I: mortality rate was 2.5% (1/40) major and minor stroke each 2.5% (1/40) and group I: 1.5% (3/195) and 1% (2/195) respectively (NS). Four to 108 months later, 30% (12/40) of group I and 21% (41/195) of group II died. CONCLUSIONS: Endarterectomy of the carotid artery under general anesthesia without use of shunt and patch in patients with or without occlusion of the contralateral carotid artery presented the same comparative results. Candidates for carotid endarterectomy should be screened systematically for coronary disease preoperatively and annual stress testing postoperatively, tactics which may improve early and late mortality rate after carotid surgery.

The cerebral effects of carbon dioxide during digital subtraction angiography in the aortic arch and its branches in rabbits.

PURPOSE: We studied the neurotoxicity of carbon dioxide as a contrast agent in the central nervous system by performing CO2 digital subtraction angiography (DSA) in the aortic arch and its branches in experimental animals. METHODS: Twenty-five rabbits underwent intraarterial CO2 DSA while under general anesthesia, during which 50 angiograms were obtained after administration of 3 mL/kg CO2. MR imaging was performed before and after the angiographic procedure. The animals were killed 12 hours later and their brains examined macroscopically and microscopically. RESULTS: Three animals died of a cause irrelevant to CO2. No animal had clinical symptoms of hemiplegia or stroke. Neither MR imaging nor macroscopic and microscopic examination of the brain revealed any ischemic infarct hemorrhage, thrombosis, or foci of necrosis. CONCLUSION: The absence of neurologic symptoms, the lack of pathologic findings at MR imaging, and the negative pathologic findings in the brain encourage further research on CO2 neurotoxicity of the central nervous system and support its application in the imaging of intracranial vessels.

Our first experience applying simultaneous bilateral carotid endarterectomy.

Simultaneous bilateral carotid endarterectomy (SBCE) has been very rarely cited in the international literature. Twelve patients underwent 24 SBCE's (Group A). They were compared with 22 bilateral staged endarterectomies in 11 (Group B) and 155 cases with unilateral endarterectomies (Group C). The indications and surgical management were similar and the accompanying risk factors were comparable in the 3 groups. Shunt or patch was not used and occlusion time was 13 +/- 2'. Total occlusion time in the SBCE was 25 +/- 3'. The results are comparable in the 3 groups. In the SBCE group one case of TIA was particularly noted together with another case with transient vocal cord paresis; however no death, myocardial infarct, respiratory problems or permanent damage of the central nerves were observed in this group. Despite the small number of our patients together with that of the international literature, it seems that a better preoperative assessment of the function of the circle of Willis in association with meticulous surgical technique and proper patient selection, encourages the tactics of simultaneous bilateral carotid endarterectomy.

A case of relapsing Kawasaki disease and review of the literature.

A review of the literature was carried out on the occasion of one case of Kawasaki disease in a small infant aged 3 months which relapsed 17 years later. Kawasaki disease is of unknown aetiology and mainly affects children under 5 years of age. It is manifested as a necrotizing vasculitis with aneurysms of the coronary arteries and the proximal medium size arteries. One hundred and fifteen thousand cases have been reported up to the present date, an incidence of 6-11/100,000 children. The evidence of coronary aneurysms range from 20-30%, while peripheral aneurysms are rare. Eighteen cases of peripheral ischemia have been reported in the international literature. The diagnosis is clinical and treatment remains symptomatic (anti-inflammatory and anticoagulant). Thrombolytic and anticoagulant management is applied in acute heart attack, and surgical bypass in chronic ischemia. Reversion of the aneurysms is observed in 60% of the cases, while relapse of the disease is possible years or decades later. Death is due to thrombosis of the coronary or rupture of the coronary or distal aneurysm. For this reason, regular fellow-up of the patients is recommended, according to the guidelines for long-term management of patients with Kawasaki disease.

The role of adrenal corticosterone in schedule-induced wheel running.

In 3 experiments, the role of adrenal corticosterone in schedule-induced wheel running was investigated. Data from the first experiment showed that bilateral adrenalectomy significantly suppressed schedule-induced wheel running, but did not influence non-scheduled wheel running. Results from a second experiment, where bilateral adrenalectomy with and without replacement of corticosterone was used, showed that the suppressant effect of adrenalectomy on schedule-induced wheel running was completely reversed by replacement of corticosterone. In Experiment 3, plasma corticosterone levels of all experimental rats were determined at the completion of the last test session. The results showed that a circulating level of corticosterone was necessary for the occurrence of schedule-induced wheel running. These findings show that adrenal corticosterone is involved in the regulation of schedule-induced wheel running.

Intravenous self-administration of phentermine in food-deprived rats: effects of abrupt refeeding and saline substitution.

The objectives in these experiments were to determine the effects on intravenous phentermine self-administration of abrupt refeeding and of saline substitution in food-deprived rats. In Experiment 1, 32 naive rats, reduced to 80% free-feeding weight (FFW), were assigned randomly to four equal-sized groups. Two groups self-administered phentermine, the other two saline over two consecutive six-day phases. In phase 1, all animals were maintained at 80% FFW, while in phase 2, one phentermine- and one saline-reinforced group was abruptly food satiated. Results showed that phentermine self-administration was suppressed. In Experiment 2, another 32 naive rats were assigned to four equal-sized groups and tested over two consecutive six-day phases. Two groups were FF, the other two were reduced to 80% FFW. In phase 1, a group of FF and 80% FFW animals self-administered phentermine, the other two saline, while in phase 2, treatments were reversed: previously phentermine-reinforced animals self-administered saline and vice versa. Findings showed that 80% FFW rats rapidly discriminate the introduction or removal of phentermine and alter responding accordingly, while FF animals respond at low rates throughout.

Food deprivation fails to potentiate intravenous self-administration of fenfluramine in naive rats.

Recent findings show that in animals, i.v. self-administration of D-amphetamine, cocaine and phentermine, which act predominantly upon catecholamine (CA) containing neurons, is potentiated following chronic restricted feeding. The objective in this experiment was to determine whether food deprivation would potentiate self-administration of fenfluramine, an anorectic compound which acts predominantly upon serotonin (5HT) containing neurons. When saline and five doses of fenfluramine were made available for i.v. self-administration to naive free-feeding (FF) rats or food-restricted (FR) rats at 80% free-feeding weight, the rate of fenfluramine-reinforced responding did not differ significantly from saline-reinforced responding at any dose or deprivation state. These data suggest that the potentiation of responding which occurs under conditions of chronic restricted feeding is specific to compounds which act predominantly upon CA containing neurons.

6-Hydroxydopamine and excitotoxin lesions of medial prefrontal cortex fail to affect schedule-induced drinking in the rat.

Schedule-induced drinking was examined in rats following 6-hydroxydopamine and N-methyl-D-aspartate lesions of the medial prefrontal cortex. 6-Hydroxydopamine reduced the concentrations of dopamine and noradrenaline in the medial prefrontal cortex to 17 and 37% of control values respectively, while changes were not observed in the nucleus accumbens. Lesions with N-methyl-D-aspartate were confined to the medial prefrontal cortex. Schedule-induced water consumption, determined over 11 consecutive 1 h/day testing sessions, was not significantly altered by either lesion. These results suggest that the mesocortical dopaminergic projection to the medial prefrontal cortex, and reciprocal projections from medial prefrontal cortex to the nucleus accumbens and the ventral tegmental area, are not essential for the acquisition of schedule-induced drinking.

Self-administration of phentermine by naive rats: effects of body weight and a food delivery schedule.

Food deprivation has been shown to increase intravenous self-administration of amphetamine and cocaine. In the present experiment, the response rates of four groups of eight rats for intravenous infusions of phentermine under free-feeding (FF) and 80% free-feeding weight (FFW) conditions in the presence and absence of a fixed time 1 min (FT-1) food delivery schedule, were compared with those of saline reinforced animals under identical conditions. The findings showed that: (1) Overall, response rates of phentermine-reinforced animals were significantly greater than were those of saline-reinforced animals; (2) 80% FFW animals self-injected significantly greater amounts of phentermine than did FF animals; and (3) the operation of an FT-1 schedule failed to affect the rate of phentermine-reinforced responding.

Phentermine self-administration in naive free-feeding and food-deprived rats: a dose response study.

In the present experiment graded doses of phentermine, an anorectic similar to amphetamine in structure and mechanism of action, were made available to naive free-feeding (FF) or 80% free-feeding weight (FFW) rats for IV self-administration. Findings showed that, in 80% FFW rats, the number of injections taken were an inverted U-shaped function of dose, whereas the amount of drug injected was a monotonically increasing function of dose. FF animals, however, failed to self-administer phentermine at rates that differed significantly from FF animals self-administering saline. These data suggest that the clinical use of anorectics which have a mechanism of action similar to amphetamine may increase the risk of drug dependence whenever weight loss is achieved.

Self-administration of low-dose cocaine by rats at reduced and recovered body weight.

Food deprivation significantly increases self-administration of cocaine in both rats and rhesus monkeys. The objective in the present investigation was to determine the effects of varying deprivational states on the level of IV low-dose (0.1 mg/kg/infusion) cocaine self-administration in rats. In the first experiment, 32 naive rats were assigned randomly to four equal-sized groups. Two groups self-administered cocaine, the other two saline over two consecutive 10-day phases. Across phase 1 all animals were free-feeding (FF), while in phase 2, one cocaine- and one saline-reinforced group were subjected to restricted feeding until they reached 80% free-feeding weight (FFW). Results showed that cocaine-reinforced responding was related inversely to body weight. In experiment 2 another 32 rats, reduced to 80% FFW, were assigned to four equal-sized groups. Two groups self-administered cocaine, the other two saline over two consecutive 10-day phases. Across phase 1 all animals were maintained at 80% FFW, while in phase 2, one cocaine- and one saline-reinforced group were abruptly food satiated. Findings showed that cocaine-reinforced responding decreased rapidly to low levels. Finally, the group of cocaine-reinforced rats maintained at 80% FFW across both phases of experiment 2 were also abruptly food satiated. Again, responding decreased rapidly to low levels.

Low dose cocaine self-administration by naive rats: effects of body weight and a fixed-time one minute food delivery schedule.

The self-administration rates of four groups of eight rats for low dose cocaine (0.1 mg/kg infusion) under free feeding and 80% body weight conditions, with and without a fixed time 1 min (FT-1) food delivery schedule, were compared with those of saline reinforced animals under the same conditions. Results indicated that (1) overall, self-administration rates were significantly greater for cocaine reinforced animals, (2) significantly higher rates of cocaine self-administration occurred in body weight reduced rats and (3) the operation of FT-1 schedule neither significantly enhanced or inhibited drug intake. In the second experiment, schedule and no schedule conditions were reversed for the sixteen 80% body weight, cocaine reinforced rats. Results showed that reversing schedule and no schedule conditions produced no significant change in drug intake. It was concluded that low dose cocaine self-administration is significantly amplified by body weight reduction.