Feeding predictability as a cognitive enrichment protects brain function and physiological status in rainbow trout: a multidisciplinary approach to assess fish welfare.

Cognitive enrichment is a promising but understudied type of environmental enrichment that aims to stimulate the cognitive abilities of animals by providing them with more opportunities to interact with (namely, to predict events than can occur) and to control their environment. In a previous study, we highlighted that farmed rainbow trout can predict daily feedings after two weeks of conditioning, the highest conditioned response being elicited by the combination of both temporal and signalled predictability. In the present study, we tested the feeding predictability that elicited the highest conditioned response in rainbow trout (both temporal and signalled by bubbles, BUBBLE + TIME treatment) as a cognitive enrichment strategy to improve their welfare. We thus analysed the long-term effects of this feeding predictability condition as compared with an unpredictable feeding condition (RANDOM treatment) on the welfare of rainbow trout, including the markers in the modulation of brain function, through a multidisciplinary approach. To reveal the brain regulatory pathways and networks involved in the long-term effects of feeding predictability, we measured gene markers of cerebral activity and plasticity, neurotransmitter pathways and physiological status of fish (oxidative stress, inflammatory status, cell type and stress status). After almost three months under these predictability conditions of feeding, we found clear evidence of improved welfare in fish from BUBBLE + TIME treatment. Feeding predictability allowed for a food anticipatory activity and resulted in fewer aggressive behaviours, burst of accelerations, and jumps before mealtime. BUBBLE + TIME fish were also less active between meals, which is in line with the observed decreased expression of transcripts related to the dopaminergic system. BUBBLE + TIME fish tented to present fewer eroded dorsal fin and infections to the pathogen Flavobacterium psychrophilum. Decreased expression of most of the studied mRNA involved in oxidative stress and immune responses confirm these tendencies else suggesting a strong role of feeding predictability on fish health status and that RANDOM fish may have undergone chronic stress. Fish emotional reactivity while isolated in a novel-tank as measured by fear behaviour and plasma cortisol levels were similar between the two treatments, as well as fish weight and size. To conclude, signalled combined with temporal predictability of feeding appears to be a promising approach of cognitive enrichment to protect brain function via the physiological status of farmed rainbow trout in the long term.

An excess of massive stars in the local 30 Doradus starburst.

The 30 Doradus star-forming region in the Large Magellanic Cloud is a nearby analog of large star-formation events in the distant universe. We determined the recent formation history and the initial mass function (IMF) of massive stars in 30 Doradus on the basis of spectroscopic observations of 247 stars more massive than 15 solar masses ([Formula: see text]). The main episode of massive star formation began about 8 million years (My) ago, and the star-formation rate seems to have declined in the last 1 My. The IMF is densely sampled up to 200 [Formula: see text] and contains 32 ± 12% more stars above 30 [Formula: see text] than predicted by a standard Salpeter IMF. In the mass range of 15 to 200 [Formula: see text], the IMF power-law exponent is [Formula: see text], shallower than the Salpeter value of 2.35.

Behavioral and psychological symptoms in Alzheimer's disease. Relation between apathy and regional cerebral perfusion.

Fundamental and therapeutic research in Alzheimer's disease (AD) focused for a long time exclusively on cognitive aspects. However, AD also frequently involves complex disorders of affect and behavior, which are currently grouped under the heading 'behavioral and psychological signs and symptoms of dementia' (BPSSD). Several rating tools have been developed over the years on the basis of a variety of source data. Some are derived from psychiatric practise or have specifically been developed for dementia, such as the Neuropsychiatric Inventory (NPI). In this study we prospectively used the NPI to examine BPSSD. Sixty-three French patients (mean age 74.7 years, SD 7.9) with a Mini-Mental State Examination (MMSE) score higher than 10 were examined. BPPSD were detected by NPI in 95. 2% of the patients. Anxiety was the most common abnormality (65.1%), followed by apathy and dysphoria (58.7%). The highest frequency x severity NPI score was observed for apathy. In order to identify the relationship between regional cerebral perfusion and apathy, 20 of these AD patients underwent a technetium-99m-bicisate SPECT protocol within the same week as the NPI evaluation. The mean age of this population was 74.4 years (SD 5.3) and the mean MMSE score was 21 (SD 4.1). The apathy NPI score was correlated with right cingulate deficit whereas the highest correlation for the MMSE was with the left temporoparietal area. This stresses the interest to focus on SPECT imaging of AD patients not only in the posterior areas. CopyrightCopyright 1999S.KargerAG,Basel

Pharmacokinetic-pharmacodynamic contributions to the convulsant activity of fluoroquinolones in rats.

The in vivo convulsant activities in rats of five representative fluoroquinolones (FQs), norfloxacin, enoxacin, sparfloxacin, fleroxacin, and pefloxacin, were compared. The experimental approach allowed distinction between the drugs' ability to reach the pharmacological receptors at the level of the central nervous system (pharmacokinetic contribution) and their ability to interact with these receptors (pharmacodynamic contribution). The presence of a methyl group on the piperazine moiety decreased the pharmacodynamic contribution to the convulsant activity by severalfold, and the ratios of concentrations of the FQs in cerebrospinal fluid (CSF) to concentrations of unbound FQs in plasma varied from about 5 to 75% as a function of lipophilicity. Interestingly, FQs with the highest intrinsic convulsant activities had the lowest levels of diffusion in CSF and vice versa. This in vivo approach provides information complementary to that of in vitro experiments and should be recommended for early preclinical assessment of a new FQ's epileptogenic risk.

Relationships between low red blood cell count and clinical response to fluoxetine in depressed elderly patients.

Biological variables specifically linked with serotonin deficiency were assessed in geriatric depression. Sixteen depressed patients, all > or = 60 years of age and with scores on the Montgomery-Asberg Depression Rating Scale (MADRS) > or = 20, were treated with fluoxetine (20 mg/day) for 42 days. Biological variables measured on days 1 and 42 included whole blood and plasma serotonin, plasma total and free tryptophan, and platelet paroxetine and ketanserin binding. Seven of the 16 patients showed a positive clinical response (i.e. MADRS score < or = 12 at day 42). The pre-treatment red blood cell count was the variable most related to clinical response; low levels were found in almost all responders. To a lesser extent, plasma free tryptophan before treatment was also correlated to therapeutic response, with lower values being found in responders. During treatment, plasma free tryptophan was increased in responders and decreased in non-responders. The finding that elderly depressed patients with low pre-treatment red blood cell counts subsequently responded to fluoxetine treatment is consistent with the view that tryptophan, the precursor of serotonin in brain, is taken up by red blood cells.

[Plasma tryptophan in a protein controlled diet in depressed patients]. / Tryptophane plasmatique à apport protéique contrôlé chez des déprimés.

Cerebral serotonin is synthetized from its blood precursor: tryptophan (TRP), an essential amino acid (6). TRP has been extensively studied since serotonine has been reported to be involved in the pathogenesis of depression (9). In one hand, brain serotonin content depends on regulation by plasma large neutral amino acids (LNAA): leucine, isoleucine, valine, tyrosine and phenylalanine that compete with TRP to cross over the blood brain barrier (7, 13). In the other hand TRP is largely linked with albumin. So, we have studied plasma total TRP, free TRP and the ratio TRP on LNAA as potential cerebral serotonin index. The aim of this study is to observe the blood variations of the biological parameters in fasting and postprandial conditions in 8 depressed women, aged from 57 to 78 years, on a short protein controlled diet: 4 women had TRP poor then rich diet and the others 4 rich then poor. Alimentary proteins modulated diets and each patient was his own control: the results under modulated diet were compared with those under normal diet at the same time. More over, 2 psychotic patients aged 58 and 70 years have been studied at the same time, in each group. Biological datas were compared with clinical evolution.

[A scale for clinical evaluation of serotonergic deficit in elderly people]. / Echelle d'évaluation clinique du déficit sérotoninergique chez les personnes âgées.

In contrast to young adults, symptoms of serotonergic deficiency are relatively undocumented in elderly subjects. Specific abnormalities of serotonergic neurotransmission are nevertheless remarkable and have clinically important repercussions in affect, as well as in cognition and behavior. The aim of this study was to develop a scale for the clinical and transnosographic quantitation of serotonergic deficiency in elderly persons (5-HT scale). Based on the data in the literature and following a preliminary study, we developed a 10-point scale. The analysis into primary components, among 155 subjects, showed a stable factorial structure and highly saturated "pure" items (62 to 90) distributed into 4 factors: "loss of control", "anxiety-insomnia", "depression" and "disturbances of behavior". The factorial structure does not depend on the psychiatric diagnosis: the 5-HT scale is not correlated with the COVI anxiety scale, the Jouvent mood scale, the Widlocher slowing down scale or the Hamilton depression scale in the subgroup of depressed subjects. Factorial analysis on the cumulated items of the 5-HT and Hamilton depression scales shows dispersion of the items on the latter scale whereas those on the 5-HT retain a factorial distribution. These data seem to confirm the clinical importance of serotonin deficiency in elderly subjects and the pertinence of the transnosographic approach. The 5-HT scale, which still requires outside validation, would seem to contribute to the clinical evaluation of this deficiency.