A novel test for evaluating horses' spontaneous visual attention is predictive of attention in operant learning tasks.

Attention is described as the ability to process selectively one aspect of the environment over others. In this study, we characterized horses' spontaneous attention by designing a novel visual attention test (VAT) that is easy to apply in the animal's home environment. The test was repeated over three consecutive days and repeated again 6 months later in order to assess inter-individual variations and intra-individual stability. Different patterns of attention have been revealed: 'overall' attention when the horse merely gazed at the stimulus and 'fixed' attention characterized by fixity and orientation of at least the visual and auditory organs towards the stimulus. The individual attention characteristics remained consistent over time (after 6 months, Spearman correlation test, P < 0.05). The validity of this novel test as a predictor of individual attentional skills was assessed by comparing the results, for the same horses, with those obtained in both a 'classical' experimental attention test the 'five-choice serial reaction time task' (5-CSRTT) and a work situation (lunge working context). Our results revealed that (i) individual variations remained consistent across tests and (ii) the VAT attention measures were not only predictive of attentional skills but also of learning abilities. Differences appeared however between the first day of testing and the following test days: attention structure on the second day was predictive of learning abilities, attention performances in the 5-CSRRT and at work. The VAT appears as a promising easy-to-use tool to assess animals' attention characteristics and the impact of different factors of variation on attention.

[Cannabis and psychosis: search of a causal link through a critical and systematic review]. / Cannabis et psychose: recherche d'un lien de causalité à partir d'une revue critique systématique de la littérature.

INTRODUCTION: Although cannabis use may be involved in the aetiology of acute psychosis, there has been considerable debate about the association observed between cannabis use and chronic psychosis. In particular, because of the frequent co-occurrence between schizophrenia and cannabis use, the question has been raised of a causal link between exposure to cannabis as a risk factor and the development of psychosis or psychotic symptoms. OBJECTIVE: The aim of this article was to examine the evidence that cannabis use causes chronic psychotic disorders by using established criteria of causality. These criteria were defined by: biologic plausibility, strength of the interaction between the risk factor and the disease, reprieability of the results, temporal sequence between the exposure to the risk factor and the beginning of the disease and existence of a dose-effect relationship. METHODS: The selected studies were found in Medline using the keywords "cannabis" and "psychosis", "cannabis" and "schizophrenia", "cannabis" and "psychotic symptoms" and "prospective" or "cohort" or "longitudinal". The selected studies were all prospective studies assessing the temporal sequence between cannabis use and emergence of psychosis or psychotic symptoms. The search strategies resulted in 60 records that were screened by reading both titles and abstracts. Seventeen studies were considered eligible, and then, after reading the full text, seven met the inclusion criteria. RESULTS: Together, the seven studies were all prospective cohorts and represented 50,275 human subjects. There were three European studies (from Sweden, Holland and Germany), one from New Zealand and one from Australia. Only one study of the seven did not show a significant association between cannabis consumption and increase of the risk of developing a psychosis. However, this study had some bias, such as low level of cannabis use and the lack of evaluation of cannabis use after inclusion. For the six other studies, data show the existence of a significant association between cannabis use and psychotic disorders (with an increased risk between 1.2 and 2.8 in Zammit et al.'s study), particularly among vulnerable individuals (that is with a prepsychotic state at the time of inclusion). Therefore, all the studies that assessed a dose-effect relationship showed this link between cannabis use and the emergence of psychosis or psychotic symptoms. The fact that all causal criteria were present in the studies suggests that cannabis use may be an independent risk factor for the development of psychosis. Results seem to be more consistent for vulnerable individuals with the hypothesis that cannabis use may precipitate psychosis, notably among vulnerable subjects. In particular, early onset of cannabis use during adolescence should be an environmental stressor that interacts with a genetic predisposition to induce a psychotic disorder. CONCLUSION: The objective of this article was to examine whether cannabis use can be an independent risk factor for chronic psychotic disorders, by using established criteria of causality. Data extracted from the selected studies showed that cannabis use may be an independent risk factor for the development of psychotic disorders. Early screening of the vulnerability to psychotic disorder should permit improved focus on prevention and information about the specific risks related to cannabis use among this population.

Postural effect on manual laterality in different tasks in captive grey-cheeked mangabey (Lophocebus albigena).

The authors examined the effects of task complexity and posture on laterality and compared lateralization during different tasks in 9 captive grey-cheeked mangabeys (Lophocebus albigena) during spontaneous food processing and 3 experimental tasks. Comparisons with data of red-capped mangabeys (Cercocebus torquatus torquatus; semiterrestrial species) were used. Less than half the monkeys were lateralized for simple everyday activities, but 6 were lateralized for complex daily activities. Moreover, all the monkeys were lateralized when performing experimental tasks. Laterality at the group level was found for the bipedal task: Mangabeys were right-handed. Complexity of tasks increases laterality at the individual level. Significant differences between the 2 species of mangabeys were found, allowing us to confirm that postural constraints are a major factor in the emergence of group handedness.

[Ectopic lingual thyroid. Apropos of 3 cases]. / La thyroïde ectopique linguale. A propos de trois cas.

Lingual thyroid is a rare cause of upper airway obstruction, dysphagia or hypothyroidism symptoms. This report describes three cases of lingual thyroid arising in women. One was in pregnancy and developed a lingual goiter and hemorrhages with hypothyroidy. The second case have been diagnosed because of a dysphagia and the third was asymptomatic and have been diagnosed during physical examination for cervical nodes. Diagnosis and possible therapeutic options are discussed regarding these three cases. Surgical therapy is appropriate for patients with clinical signs of upper airway obstruction or when malignant degeneration is suspected. Without of clinical sign, substitutive therapy with thyroid hormone allows the stabilization or the regression of the ectopic thyroid.

[Plasmapheresis and acute attacks of uveitis]. / Plasmaphérèses et poussées aiguës d'uvéite.

Our study concerns the effects of plasma exchange in acute attacks of posterior or total chronic uveitis. The treatment undertaken in 10 patients consisted of 8 plasma exchanges in a 2 weeks period, associated with a corticosteroid and immunosuppressive therapy. Immediately after the plasma exchanges, there was a significant improvement in visual acuity and a decrease in inflammatory activity in most patients (70%). Plasma exchange seems to be an interesting adjuvant in the difficult treatment of some uveitis.

Immunological analysis of the aqueous humour in candida endophthalmitis. I: Experimental study.

An immunological study of aqueous humour and serum was carried out in experimental ocular candidosis in rabbits. Anti-candida antibody titres, immunoglobulin G, and albumin levels were evaluated in the aqueous humour and in the serum. A local synthesis of anti-candida antibodies was detected in numerous rabbits at the height of clinical activity of the lesions.

Immunological analysis of the aqueous humour in candida endophthalmitis. II: Clinical study.

An anterior chamber paracentesis was carried out on six patients with candida endophthalmitis and on control subjects. We endeavoured to find out if there was local production of antibodies by evaluating the anti-candida antibody titres, the immunoglobulin G, and the albumin levels in the aqueous humour and in the serum. A significant difference in the level of specific antibodies between patients and controls was found. Local synthesis of anti-candida antibodies was discovered in five out of six patients with candida endophthalmitis. There would seem to be a correlation between the severity of uveitis and antibody titres.

Experimental study of the intra-ocular penetration of ketoconazole in rabbits.

We studied 11 healthy rabbits and 15 rabbits with experimentally induced Candida endophthalmitis. Using a microbiological procedure, ketoconazole levels were determined 1, 2, 4, 8 and 24 h after its oral administration. Ketoconazole penetration was average in the aqueous humour, significant in tears and poor in the vitreous. Vitreous penetration was not detectable in healthy rabbits or in rabbits with chorioretinits exhibiting little or no vitreous reaction. Such penetration was only significant in rabbits exhibiting massive vitreous exudation; however, in such rabbits, penetration was not always observed (only in 2 out of 6 animals). Given these results, the treatment of Candida endophthalmitis in humans using ketoconazole would appear to be of questionable value.

[Maculopathy in typical retinitis pigmentosa apropos of 33 cases]. / La maculopathie dans la rétinopathie pigmentaire typique. A propos de 33 cas.

The authors studied 33 maculopathies in 54 patients affected by typic retinitis pigmentosa: atrophic macular degeneration 31 cases (49%); cystoïd macular oedema: 1 case (3%) and macular retraction syndrome: 1 case (3%). These results are confronted with those of the literature. Two therapeutical trials based on pathogenical hypothesis were conducted. The patient with cystoïd macular oedema was treated by Hyperbar oxygenotherapy, basing one of selves on the theory ischemia. Six other patients with atrophic foveolopathies were treated by the cyclophosphamide, according to the autoimmune theory. In the first trial, the result was positive. In the second one, the results did not permit any available conclusion.

[Local production of specific antibodies in the aqueous humor in experimental Candida endophthalmia in rabbits]. / Etude de la production locale d'anticorps spécifiques dans l'humeur aqueuse dans l'endophtalmie expérimentale à Candida du lapin.

An increasing frequency of ocular lesions due to Candida albicans has been reported, but clinical detection of lesions, which may cause permanent blindness, remains difficult. Hematogenous endophthalmitis caused by Candida albicans in the rabbit is a useful model to study the pathogenesis of the disease, and perhaps to find new methods of biological diagnosis. A suspension of Candida albicans was injected in 15 rabbits, according to the method described by Edwards et al. In 1975, causing uni or bilateral chorioretinitis in 12 of them. Unaffected eyes were chosen as controls. After aspiration of the anterior chamber fluid, serum and aqueous humour titres of specific antibodies were determined. A local synthesis of IgG antibodies was detected, after comparison of the titres of specific antibodies in the aqueous humour and in the serum, related to the serum and aqueous humour concentrations of IgG antibodies. According to a formula proposed by Witmer and Desmonts in ocular lesions due to different pathological agents, we calculated the "C" coefficient: C = antibody titres aqueous humor/serum x IgG serum/aqueous humor. A local synthesis of specific antibodies in cases of experimental endophthalmitis leads us to believe that aqueous humour aspiration could be used in the diagnosis of endophthalmitis in humans.

[Value of adjustable sutures in the treatment of diplopia]. / L'intérêt des sutures ajustables dans le traitement de la diplopie.

Adjustable sutures have been used as a curative procedure in 31 cases of diplopia, 16 cases of plegic causes, 4 cases of acute concomitant squint and 11 cases of mechanical strabismus: thyroid myopathy, orbital fracture, oculomotor imbalance after scleral indentation. In oculomotor paralysis if a few functional motor units remained at plegic muscle level, we were able to obtain new rotational balance by combining, with adjustable sutures, recession and resection of the couple agonist-antagonist. On the other hand, if no functional motor unit remained, it was then necessary to turn to the muscular translocation process modulated by adjustable surgery. In acute concomitant strabismus, adjustable retroposition of the medial rectus enabled us to fall back into an area controlled by fusional vergencies. Lastly, in mechanical strabismus by passive limitation, adjustable sutures usually enabled hyperaction of the contralateral synergists to be controlled and to bind a new rotational balance, compatible with a simple binocular field of vision. The advantage of this technique was to adapt, on adjustment, the motor response to the new innervational background which had disappeared under anaesthesia.