Stereotactic MRI in DYT1 dystonia: focal signal abnormalities in the basal ganglia do not contraindicate deep brain stimulation.

AIMS: To study stereotactic magnetic resonance imaging (MRI) features of the basal ganglia in DYT1 primary dystonia. METHODS: Twenty-five genetically confirmed DYT1 dystonia patients (age range, 8-66 years; mean age, 22 years) underwent brain MRI under general anesthesia at the time of globus pallidus internus (GPi) deep brain stimulation (DBS) surgery. MR images were retrospectively reviewed for signal intensity alterations. Clinical improvement of patients was assessed by comparing pre- and postoperative Burke-Fahn-Marsden Dystonia Rating Scale scores. RESULTS: Seventeen patients out of 25 (68%) exhibited T(1)-weighted hypointense/T(2)-weighted hyperintense signal abnormalities in the putamen and globus pallidus on MR images. Signals were isointense with cerebrospinal fluid in all sequences. The mean volume of focal signal abnormalities was 15 mm(3) (maximum, 154.5 mm(3)). The total volume of focal signal abnormalities in the basal ganglia was correlated with the duration of the disease (p = 0.01). Although clinical outcome did not differ as a function of the presence of focal signal abnormalities overall, patients with signals within the GPi tended to show lesser improvement (p = 0.04). CONCLUSIONS: T(1)-hypointense/T(2)-hyperintense signal abnormalities are common findings in the putamen and globus pallidus of DYT1 patients but do not contraindicate DBS. However, their presence within the GPi may reduce the efficacy of DBS treatment.

[Can multislice helical computed tomography replace conventional angiography in the diagnosis of non traumatic subarachnoid hemorrhage?]. / L'angio-scanner cérébral multibarrette peut-il supplanter l'angiographie conventionnelle dans le diagnostic étiologique des hémorragies sous-arachnoïdiennes?

AIM OF THE STUDY: To evaluate the reliability of CT angiography in the diagnosis of non traumatic subarachnoid hemorrhage. MATERIALS AND METHODS: We prospectively studied 57 patients presenting with non traumatic subarachnoid hemorrhage. In all cases, CT angiography of the circle of Willis was performed, followed by conventional angiography. We compared the results of both techniques, with conventional angiography considered as the gold standard. RESULTS: The specificity of CT angiography for diagnosing intracranial aneurysms was 100% with sensitivity and negative predictive values of 86% and 65% respectively. The aneurysms that were not diagnosed on CT angiography were located on the supra-cavernous internal carotid artery and their size was less than 5mm. Futhermore CT angiography failed to diagnose the other causes of subarachnoid hemorrhage. CONCLUSION: CT angiography can be considered as a first line imaging technique for diagnosis of non traumatic subarachnoid hemorrhage. However, conventional angiography including three dimensional acquisitions must be performed for all cases where the cause of hemorrhage remains undiagnosed at CT angiography.

[A collective malarial infestation during a humanitarian mission in west Africa]. / Infestation paludique collective à l'occasion d'une mission humanitaire en Afrique de l'ouest.

Four truck drivers involved in a humanitarian mission across the Sahara towards Mali fell ill 15 days after their return. Plasmodium falciparum malaria (thankfully, non pernicious) was diagnosed with 3 to 4 days delay. The four drivers had been treated with chloroquine and proguanil but the dosage may have been insufficient with regard to their body weight (average weight = 110 kg). These 4 travelers had all slept outside (in Tintane, near Kiffa in Mauritania), without any anti-vectorial protection, whereas their other 8 companions (none of whom caught malaria) had slept in their vehicles. The evolution of the 4 cases was favourable despite the difficulties involved in urgently obtaining sufficient amounts of quinine for treatment. How can these cases be explained in relation to prophylactic treatment of associated chloroquine and proguanil? One explanation might be resistance of the P. falciparum strain. We were unable to study this possibility. The high incidence and similitude of cases points towards a hypothesis of resistance both to proguanil and chloroquine. Resistance to chloroquine, as has been formally ascertained in Mauritania, reinforces such a conviction. And yet prophylaxis does not prevent pernicious malaria. This clinical form of the disease, with P. falciparum primo-invasion occurring under rigorous chemoprophylaxis is characteristic of a partially resistant strain. The most reasonable explanation besides "chance" is that we are dealing here with a partially resistant strain of Plasmodium falciparum which is thus also partially sensitive to--in this case highly effective--therapeutic treatment. Indeed, chloroquino-resistant strains are more sensitive to mefloquine and halofantrine. Another explanation might be under-dosage of Savarine with relation to the body weight of these 4 patients. We should be aware of adapting more rigorously the posology of prescribed prophylaxis. But above all, this outbreak should remind us that we should recommend to travelers and drivers planning a trip to Sub-Saharan Africa to take with them anti-vectorial protective gear. Finally, the observation of these cases indicates once more the difficulty in France of establishing a proper diagnosis in face of malaria. Health personnel must systematically call to mind malaria in face of thrombopenia or fever following a sojourn in an endemic area even when chemoprophylaxis has been correctly followed.

Corneal toxicity studies in rabbits and dogs with hydroxyethyl cellulose and benzalkonium chloride.

Hydroxyethyl cellulose (HEC) is used as a viscosity-enhancing agent in ophthalmic formulations to prolong corneal contact time and increase intraocular drug levels. Benzalkonium chloride (BAK) is the preservative most frequently used in ophthalmic formulations. Corneal epithelial changes were seen by slit lamp and light microscopic examination in rabbits but not dogs after multiple instillations of an ophthalmic vehicle containing 0.01% BAK and 0.5% HEC. Microscopically, there was sloughing of superficial epithelial cells and a slight loss of polarity of the basal cells. Formulations with 0.01% BAK and HEC, at concentrations between 0.3 and 0.8%; caused these changes but not with BAK or HEC alone. It was concluded that hydroxyethyl cellulose increased the viscosity and prolonged the contact time of BAK with cornea resulting in corneal epithelial damage in the rabbit. Physiological and anatomical features of the rabbit combined with the increased contact time were concluded to favor these changes in this species. The results confirm that the rabbit is a sensitive and unique species in studies of ocular toxicity of drugs.

Corneal endothelial changes with azone, a penetration enhancer.

Azone has been used to enhance percutaneous absorption. Its ability to improve penetration makes it an attractive candidate for incorporation into ophthalmic formulations to increase therapeutic action of a drug or achieve an equivalent effect with a lower concentration of the active ingredients. Ophthalmic vehicles containing 0, 1, or 2% Azone were studied to determine their ocular irritation potential in the rabbit. The vehicle ingredients were poloxamer 188, hydroxy-ethylcellulose, benzalkonium chloride and phosphate buffer. Rabbits received 30mcl topically of each of the test products three times daily for 29 days. Clinical and histopathological evidence of ocular toxicity occurred in eyes treated with the vehicle containing 1 or 2% Azone, but not in the vehicle without Azone. Clinical signs of ocular irritation were transient and included redness of conjunctivae and iris, discharge and corneal edema. Scanning electron microscopy and semi-thin sections revealed corneal changes characterized by ballooning and vacuolation of endothelial cells resulting in distortion of the typical polygonal appearance. These results indicate that instillation of ophthalmic vehicles containing 1 or 2% Azone damages corneal endothelial cells of the rabbit. It is not clear, however, if this irritation is due to the direct action of Azone on the endothelium or the enhanced penetration of potential irritants in the formulation such as benzalkonium chloride.

Localization of human A, B and H isoantigens in Cynomolgus monkey tissues.

The presence and distribution of human A, B and H isoantigens were demonstrated in Cynomolgus monkey (Macaca fascicularis) by means of red cell adherence test. Although no human antigens were found on primate erythrocytes, various epithelial tissues revealed the presence of A, B or H antigenic substance. The distribution and localization was similar to that found in human tissues. Majority of specimens from each individual animal possessed only 1 human type isoantigen with the exception of the salivary and sweat glands, where all animals showed the presence of H antigen in addition to other specificity, and of Brunner's gland, where all sections reacted positively also for A antigen.

The management of a squirrel monkey (Saimiri sciureus) unit.

Biological, particularly reproductive data for the squirrel monkey were reviewed. Information was also given on the care, diet, maintenance, health status, and handling of the species. The value of squirrel monkey in research was discussed. It was concluded that a controlled monkey unit produces a more homogeneous population than one would find in a natural environment and does not deplete the natural populations.