Induced Cognitive Impairments Reversed by Grafts of Neural Precursors: A Longitudinal Study in a Macaque Model of Parkinson's Disease.

Parkinson's disease (PD) evolves over an extended and variable period in humans; years prior to the onset of classical motor symptoms, sleep and biological rhythm disorders develop, significantly impacting the quality-of-life of patients. Circadian-rhythm disorders are accompanied by mild cognitive deficits that progressively worsen with disease progression and can constitute a severe burden for patients at later stages. The gold-standard 6-methyl-1-methyl-4-phenyl-1,2,3,6-tetrahydropyridin (MPTP) macaque model of PD recapitulates the progression of motor and nonmotor symptoms over contracted periods of time. Here, this multidisciplinary/multiparametric study follows, in five animals, the steady progression of motor and nonmotor symptoms and describes their reversal following grafts of neural precursors in diverse functional domains of the basal ganglia. Results show unprecedented recovery from cognitive symptoms in addition to a strong clinical motor recuperation. Both motor and cognitive recovery and partial circadian rhythm recovery correlate with the degree of graft integration, and in a subset of animals, with in vivo levels of striatal dopaminergic innervation and function. The present study provides empirical evidence that integration of neural precursors following transplantation efficiently restores function at multiple levels in parkinsonian nonhuman primates and, given interindividuality of disease progression and recovery, underlines the importance of longitudinal multidisciplinary assessments in view of clinical translation.

Lipid-induced thermogenesis is up-regulated by the first cold-water immersions in juvenile penguins.

The passage from shore to marine life is a critical step in the development of juvenile penguins and is characterized by a fuel selection towards lipid oxidation concomitant to an enhancement of lipid-induced thermogenesis. However, mechanisms of such thermogenic improvement at fledging remain undefined. We used two different groups of pre-fledging king penguins (Aptenodytes patagonicus) to investigate the specific contribution of cold exposure during water immersion to lipid metabolism. Terrestrial penguins that had never been immersed in cold water were compared with experimentally cold-water immersed juveniles. Experimentally immersed penguins underwent ten successive immersions at approximately 9-10 °C for 5 h over 3 weeks. We evaluated adaptive thermogenesis by measuring body temperature, metabolic rate and shivering activity in fully immersed penguins exposed to water temperatures ranging from 12 to 29 °C. Both never-immersed and experimentally immersed penguins were able to maintain their homeothermy in cold water, exhibiting similar thermogenic activity. In vivo, perfusion of lipid emulsion at thermoneutrality induced a twofold larger calorigenic response in experimentally immersed than in never-immersed birds. In vitro, the respiratory rates and the oxidative phosphorylation efficiency of isolated muscle mitochondria were not improved with cold-water immersions. The present study shows that acclimation to cold water only partially reproduced the fuel selection towards lipid oxidation that characterizes penguin acclimatization to marine life.

External quality assessment of national public health laboratories in Africa, 2002-2009.

OBJECTIVE: To describe findings from an external quality assessment programme involving laboratories in Africa that routinely investigate epidemic-prone diseases. METHODS: Beginning in 2002, the Regional Office for Africa of the World Health Organization (WHO) invited national public health laboratories and related facilities in Africa to participate in the programme. Three surveys comprising specimens and questionnaires associated with bacterial enteric diseases, bacterial meningitis, plague, tuberculosis and malaria were sent annually to test participants' diagnostic proficiency. Identical surveys were sent to referee laboratories for quality control. Materials were prepared, packaged and shipped in accordance with standard protocols. Findings and reports were due within 30 days. Key methodological decisions and test results were categorized as acceptable or unacceptable on the basis of consensus feedback from referees, using established grading schemes. FINDINGS: Between 2002 and 2009, participation increased from 30 to 48 Member States of the WHO and from 39 to 78 laboratories. Each survey was returned by 64-93% of participants. Mean turnaround time was 25.9 days. For bacterial enteric diseases and meningitis components, bacterial identification was acceptable in 65% and 69% of challenges, respectively, but serotyping and antibiotic susceptibility testing and reporting were frequently unacceptable. Microscopy was acceptable for 73% of plague challenges. Tuberculosis microscopy was satisfactorily performed, with 87% of responses receiving acceptable scores. In the malaria component, 82% of responses received acceptable scores for species identification but only 51% of parasite quantitation scores were acceptable. CONCLUSION: The external quality assessment programme consistently identified certain functional deficiencies requiring strengthening that were present in African public health microbiology laboratories.

Forced expression of LIM homeodomain transcription factor 1b enhances differentiation of mouse embryonic stem cells into serotonergic neurons.

The LIM homeodomain transcription factor 1b (Lmx1b) is a key factor in the specification of the serotonergic neurotransmitter phenotype. Here, we explored the capacity of Lmx1b to direct differentiation of mouse embryonic stem (mES) cells into serotonergic neurons. mES cells stably expressing human Lmx1b were generated by lentiviral vector infection. Clones expressing Lmx1b at a low level showed increased neurogenesis and elevated production of neurons expressing serotonin, serotonin transporter, tryptophan hydroxylase 2, and transcription factor Pet1, the landmarks of serotonergic differentiation. To explore the role of Lmx1b in the specification of the serotonin neurotransmission phenotype further, a conditional system making use of a floxed inducible vector targeted into the ROSA26 locus and a hormone-dependent Cre recombinase was engineered. This novel strategy was tested with the reporter gene encoding human placental alkaline phosphatase, and demonstrated its capacity to drive transgene expression in nestin(+) neural progenitors (NPs) and in Tuj1(+) neurons. When it was applied to inducible expression of human Lmx1b, it resulted in elevated expression of serotonergic markers. Treatment of neural precursors with the floor plate signal Sonic hedgehog further enhanced differentiation of Lmx1b-overexpressing NPs into neurons expressing 5-HT, serotonin transporter, tryptophan hydroxylase 2, and Pet1, when compared with Lmx1b-nonexpressing progenitors. Together, our results demonstrate the capacity of Lmx1b to specify a serotonin neurotransmitter phenotype when overexpressed in mES cell-derived NPs.

Long-term fasting decreases mitochondrial avian UCP-mediated oxygen consumption in hypometabolic king penguins.

In endotherms, regulation of the degree of mitochondrial coupling affects cell metabolic efficiency. Thus it may be a key contributor to minimizing metabolic rate during long periods of fasting. The aim of the present study was to investigate whether variation in mitochondrial avian uncoupling proteins (avUCP), as putative regulators of mitochondrial oxidative phosphorylation, may contribute to the ability of king penguins (Aptenodytes patagonicus) to withstand fasting for several weeks. After 20 days of fasting, king penguins showed a reduced rate of whole animal oxygen consumption (Vo2; -33%) at rest, together with a reduced abundance of avUCP and peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC1-alpha) mRNA in pectoralis muscle (-54%, -36%, respectively). These parameters were restored after the birds had been refed for 3 days. Furthermore, in recently fed, but not in fasted penguins, isolated muscle mitochondria showed a guanosine diphosphate-inhibited, fatty acid plus superoxide-activated respiration, indicating the presence of a functional UCP. It was calculated that variation in mitochondrial UCP-dependent respiration in vitro may contribute to nearly 20% of the difference in resting Vo2 between fed or refed penguins and fasted penguins measured in vivo. These results suggest that the lowering of avUCP activity during periods of long-term energetic restriction may contribute to the reduction in metabolic rate and hence the ability of king penguins to face prolonged periods of fasting.

Genetic diversity and genotype multiplicity of Plasmodium falciparum infections in symptomatic individuals living in Bangui (CAR).

This study provides the first estimate of the genetic diversity and genotype multiplicity of Plasmodium falciparum infections in symptomatic individuals living in Bangui (Central African Republic, CAR). Three hundred thirty six clinical isolates were used for analysis of parasite population polymorphism and genotyped by nested-PCR of msp-1 block 2, and msp-2 block 3. We found a very high level of polymorphism, with, respectively, 17 and 25 different alleles at the msp-1 and msp-2 loci and a high percentage of multiclonal infections (42.7% with msp-1 and 76.7% with msp-2), with a mean of 1.7 genotype with msp-1 and 2.8 with msp-2. We observed that (i) multiclonal infections and allelic polymorphism of msp-2 were significantly more frequent in Southern districts than in Northern districts of Bangui suggesting that the epidemiological features of P. falciparum may vary within Bangui and (ii) showed that immunocompromised HIV-positive patients tend to have a lower average number of msp-2 allele per isolate than immunocompetent patients.

Association of failures of seven-day courses of artesunate in a non-immune population in Bangui, Central African Republic with decreased sensitivity of Plasmodium falciparum.

We assessed the efficacy and safety of a seven-day course of artesunate for the treatment of uncomplicated Plasmodium falciparum malaria in 55 non-immune patients living in Bangui, Central African Republic. The parasitologic cure rates were 100%, 95%, and 85% on days 14, 28, and 42, respectively. There were no significant differences in parasitemia density, 50% inhibitory concentration of dihydroartemisinin, and frequency of mutant P. falciparum multidrug resistance 1 codon 86 between patients who were cured and those who displayed recrudescence. However, the 90% inhibitory concentration for dihydroartemisinin and the number of genotypes isolated were both higher in the recrudescent patients (five- and two-fold, respectively). We found an association between recrudescence and decreased sensitivity. This suggests that the use of artemisinin compounds alone will select resistant strains. We conclude that artesunate should not be used in monotherapy even in seven-day courses, but only in combination with other anti-malarials to prevent the emergence of resistant P. falciparum.