Plasmodium knowlesi and human malaria parasites in Khan Phu, Vietnam: Gametocyte production in humans and frequent co-infection of mosquitoes.

Four species of malaria parasite, Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae and Plasmodium knowlesi infect humans living in the Khanh Phu commune, Khanh Hoa Province, Vietnam. The latter species also infects wild macaque monkeys in this region. In order to understand the transmission dynamics of the three species, we attempted to detect gametocytes of the three species in the blood of infected individuals, and sporozoites in the salivary glands of mosquitoes from the same region. For the detection of gametocyte-specific mRNA, we targeted region 3 of pfg377, pvs25, pmg and pks25 as indicators of the presence of P. falciparum, P. vivax, P. malariae and P. knowlesi gametocytes, respectively. Gametocyte-specific mRNA was present in 37, 61, 0 and 47% of people infected with P. falciparum (n = 95), P. vivax (n = 69), P. malariae (n = 6) or P. knowlesi (n = 32), respectively. We found that 70% of mosquitoes that had P. knowlesi in their salivary glands also carried human malaria parasites, suggesting that mosquitoes are infected with P. knowlesi from human infections.

Experimental dataset of the impact assessment of vegetable intercropping on agroeconomic performances, pests and beneficials, and soil resources.

The data presented in this article were collected in the field at an experimental station in southern France under a Mediterranean climate. Experiments were conducted under three plastic walk-in tunnels used as blocks with organic farming practices over two successive years in a completely randomized design. The aim was to compare the intercropping of sweet pepper with basil, onion, lettuce, parsley or French bean to a sole crop of sweet pepper used as a control. The dataset provides information on cultural practices with details on inputs and working times used to estimate economic costs. The data also describe the climatic conditions under tunnels as well as the dynamics of soil nitrate concentration and water tension over time through treatments. Yields, economic benefits and the rates of products with visual defects are presented. In addition, some variables applied exclusively to sweet pepper crops, namely nitrate concentration in petiole sap, growth parameters, abundance of aerial pests and beneficials, incidence of root necrosis, arbuscular mycorrhizal fungi colonization rates and diversity in roots. The field dataset is made publicly available to allow free and easy access for the scientific and professional community to enable analysis and reuse. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Interim laboratory testing guidance for the detection of non-tuberculous Mycobacterium (NTM) infections in post-operative patients exposed to heater-cooler units.

The advice contained in this document should be read in conjunction with relevant federal, provincial, territorial and local legislation, regulations, and policies. Recommended measures should not be regarded as rigid standards, but principles and recommendations to inform the development of guidance. This advice is based on currently available scientific evidence and adopts a precautionary approach where the evidence is lacking or inconclusive. It was approved for publication on December 5, 2016. It is subject to review and change as new information becomes available. The main changes to this version include additions to: Case load reported to date, Sarcoidosis-like disease as an Indicator, Whole Genome Sequencing effort, links to Provincial and Territorial Lab Services and Health Canada reporting.

Synthesis of CeO2@SiO2 core-shell nanoparticles by water-in-oil microemulsion. Preparation of functional thin film.

Synthesis of nanoparticles under restricted environment offered by water-in-oil (W/O) microemulsions provides excellent control over particle size and shape, and inter-particle spacing. Such an environment has been involved to synthesize silica nanoparticles with a CeO2 core, so-called CeO2@SiO2. Aqueous fluids made up of ceria nanoparticles with a size close to 5 nm have been used as the water phase component. The starting CeO2 sols and obtained CeO2@SiO2 nanoparticles have been characterized by dynamic light scattering (DLS), X-ray diffraction, scanning and transmission electron microscopy, and specific surface area measurements. The microemulsion process has been characterized by DLS. Preliminary results on CeO2@SiO2 thin films are presented.

Rhombomere-specific origin of branchial and visceral motoneurons of the facial nerve in the rat embryo.

The goal of this study was to localize selectively the facial nerve branchial and visceral motoneurons in the rat embryo hindbrain. This was achieved by injecting dextran amines into the peripheral facial nerve on embryos maintained in an artificial cerebrospinal fluid. Sprague-Dawley rat embryos 13, 14, and 15 days old (E13, E14, E15) were obtained by cesarean section. Branchial motoneurons were first labeled at E13. They were close to the midline and migrated from rhombomere (r) 4 toward r5 and r6. By E15, they had migrated caudally and ventrolaterally into the former location of r6. Most of them had reached their "adult" position by E15. Another group of motoneurons, the accessory facial nucleus, was found in r4 at E13 and in corresponding regions at later stages. Visceral motoneurons were labeled from the periphery at all stages. At E13, they were mainly in r5 but also in r2, r3, r4, and r6. At E14, most of them had migrated laterally, and, by E15, they were in the prospective parvocellular reticular formation. They could be divided into two subgroups: a more rostral one with fibers that made loops close to the midline and a more caudal one with fibers that went directly to the exit. The findings presented here show that most branchial and visceral motoneurons of the facial nerve are born in different and specific rhombomeres. Interestingly, developmental genes are expressed specifically in these rhombomeres and could be involved in the genesis of the facial and superior salivatory nuclei.

Regional patterning of reticulospinal and vestibulospinal neurons in the hindbrain of mouse and rat embryos.

The dispositions and axonal trajectories of bulbospinal neurons in the pons and medulla of mouse and rat embryos is described from the earliest times these projections can be labelled retrogradely from the cervical spinal cord. Reticulospinal and vestibulospinal neurons are clustered into identifiable groups, each with a characteristic combination of spatial domain and axon trajectory. The various groups can be labelled retrogradely in a specific developmental sequence. The position of some groups shifts from medial to lateral with development, apparently through cell migration. These observations show that the basic regional organization of the reticulospinal and vestibulospinal projections is similar in mouse and rat and is already established during early stages of axon outgrowth.

Histogenesis of the subthalamic nucleus.

Literature presents divergent hypotheses on the histogenesis of the subthalamic nucleus. The basal plate of the mesencephalon, the dorsal hypothalamus (or the longitudinal subthalamic zone) and an area closely related to the mammillary nucleus have all been proposed as the site of origin of the neurons of the subthalamic nucleus. However, based on the selective labelling of neurons of this nucleus by the [3H]thymidine ARG technique, our results clearly show that a germinative zone lying caudally along the dorsal aspect of the mammillary recess is responsible for the formation of the neurons of the subthalamic nucleus. From this site of origin, the neurons migrate radially and then tangentially and dorsally along the marginal layer of the ventral diencephalon. The present study gives a detailed account of the histogenesis of the subthalamic nucleus of the rat through successive stage of development. Our data also show that the same proliferative neuroepithelial matrix that gives rise to the subthalamic neurons is also responsible for the genesis of the neurons of the supramammillary and submammillothalamic nuclei. Some aspects of the cytological maturation of the neurons of the subthalamic nucleus are also given.

Histogenesis of the striopallidal system in the rat. Neurogenesis of its neurons.

This study discusses the histogenesis of the structures of the extrapyramidal system. The first part based on [3H]thymidine autoradiography provides data on the time of origin of the various neuronal populations that characterize different structures of the extrapyramidal system. Such data are essential to any further study dealing with the localization of the different sites of origin of the neurons along the ependymal matrix and with their migration during the histogenetic sequences leading to their definitive pattern of adult distribution. The neurons of globus pallidus and of the entopeduncular nucleus are generated on days 12-15 and days 11-14, respectively. A peak of neurogenesis occurs on day 12 for the entopeduncular nucleus and on day 14 for the globus pallidus. In the pallidum, the first neurons to form on day 12 settle caudally, while neurons generated on day 15 settle in the rostral extremity. The genesis of the medium-sized neurons of the neostriatum extends from day 12 to at least postnatal day 2. A peak is obvious on day 15. Although the neurogenesis of these neurons follows a mild caudorostral gradient, a more careful examination reveals four different patterns of settlement according to the area involved and the period of gestation. At the level of the caudal neostriatum, the neurons display a clear mediolateral spatiotemporal gradient. More rostrally, the neurons generated on days 13, 14 and 15 show two patterns of settlement. On the one hand, many neurons settle rather densely along the external capsule on day 13, occupying more rostral levels on days 14 and 15. On the other hand, in the body of the neostriatum, clusters of isochronically generated neurons are obvious. Later, newly generated neurons display a rather homogeneous distribution in the structure. A parallel is drawn between these patterns of development and the patterns of distribution of afferent terminals or neurotransmitters. The large chromophilic neurons of the neostriatum appear exclusively during the early period. Two peaks of neurogenesis are apparent. The one on day 13 comprises neurons that settle caudally. It is contemporaneous to the neurogenesis of the adjacent basal nucleus. The second peak occurs on day 15 and corresponds to that of the medium-sized neurons.

Vertically oriented alternating acetylcholinesterase rich and poor territories in laminae VI, VII, VIII of the lumbosacral cord of the rat.

The pharmaco-histochemical method for the demonstration of acetylcholinesterase has been applied to study the spinal cord of the rat. Twenty rats were treated with di-isopropylphosphofluoridate at various time intervals before death and their lumbosacral cord sectioned in either the sagittal, horizontal or transverse plane. Under such conditions, the acetylcholinesterase activity of the neuropile which normally masks many neurons is minimal. The distribution of acetylcholinesterase-containing neurons corresponds to that described previously by various authors, but now the acetylcholinesterase-containing perikarya and their processes may be visualized to a degree not previously attained. This aspect of the technique has allowed us to observe very clearly some features of the internal organization of the spinal cord at the lumbosacral level. The original finding of the present work is the disclosure of alternating bands of dark and light acetylcholinesterase activity at the level of the intermediate grey (laminae VI, VII and VIII) along the rostrocaudal extent of the lumbosacral segments of the rat spinal cord. Dendritic bundling extending over long distances has also been observed at different sites in the ventral horn and in the intermediolateral cell column.

Transected spinal cords grafted with in situ self-assembled collagen matrices.

The purpose of this work was to evaluate if the implantation into the gap of a transected spinal cord of a biomaterial providing a scaffolding structure for tissue ingrowth would favor the permeation and the growth of regenerating axons across the spinal-bioimplant interface. The interstump gap of rat transected spinal cords was injected with an ice-cold neutral solution of collagen, either alone or mixed with glyoxal, a harmless tanning agent. Upon warming to the temperature of the tissue, the fluid implant self-assembled forming a loose fibrillar network which simultaneously re-established a physical continuity to the transected organ. At various post-implantation timepoints, the bioimplants were studied by light microscopy, with the picrosirius-polarization method and with scanning electron microscopy. We observed that the bioimplants evolved following three overlapping phases: first a massive inflammatory response characterized by the invasion of cells of heterogeneous nature, then, a phase where microcysts predominated and during which, there is a major remodeling of the biomatrix by the deposition of newly synthesized collagen and of a periodic acid Schiff-positive material. Finally, a regeneration phase occurred where astroglial processes followed by regenerating axons invaded the biomatrix. Three months after implantation, spinal axons had grown from the two spinal stumps and penetrated the bioimplant across at least one lesion interface. However, the glyoxal-tanned collagen matrices showed a better biostability and durability than collagen alone. We conclude that the histopathological reaction of the mammalian lesioned spinal cord, when adequately directed by a scaffolding structure can be beneficial for the expression of the intrinsic regenerative capacity of the spinal cord tissue.

Histogenesis at the level of the basal forebrain: the entopeduncular nucleus.

This study shows that the neurons of the entopeduncular nucleus are derived from a longitudinal slab of isochronically generated neurons on day 11 and 15 h of gestation. Many neurons of this longitudinal slab which we have named the basal forebrain cell column, originate from an ependymal matrix closely associated with the ventral diencephalic sulcus and later become associated with the basal forebrain bundle. Other neurons also originate from the ependymal matrix at the site of emergence of the optic recess and keep close relationships with the optic chiasma through the following stages of development to form the retrochiasmatic nucleus. During the second half of day 12 of gestation, the mantle layer of the forebrain shows an early zone of differentiation along its ventrolateral aspect. At this stage, the basal forebrain cell column extends unbroken from the tuberculum posterius to the chiasmatic plate primordium (site of generation of the retrochiasmatic nucleus). At the level of the caudal aspect of the optic stalk however, the basal forebrain cell column divides in two limbs associated to the ventral and dorsal edges of the optic stalk as it emerges from the forebrain. On day 14 of gestation, the neurons of the dorsal limb of the basal forebrain cell column occupy the mantle layer of the neural tube at least as far rostrally as the ventricular elevation in front of the optic stalk in the floor of the foramen of Monro. The neurons derived from the basal forebrain cell column begin breaking up into a series of more definite nuclei at later stages of development. The main finding of this study is the disclosure of the fact that the entopeduncular nucleus as well as other cell groups as dissimilar as the lateral preoptic area, the central, medial and anterior cortical amygdaloid complex and neurons of the dorsal hypothalamic area appear to be embryologically related, as they are all derived from a common longitudinal slab of the matrix of the forebrain.

Isthmic origin of neurons of the rat substantia nigra.

This study provides new data on the time of origin, the generation site and the migration route of the young neurons of the substantia nigra of the rat during embryogenesis. The neurons of the substantia nigra are generated on day 12, 13, 14 and 15 of gestation. They settle following a light spatiotemporal rostrocaudal gradient from day 12 to 15. The neurons of the substantia nigra are generated at two different points of the basal plate at the level of the fovea isthmi (meso-isthmic junction) and migrate in radial pattern as two definite streams toward the ventral mesencephalon. From this point they move rostralwards along the surface towards their final site. The main findings of this work are the disclosure that the neurons of the substantia nigra are generated in the region of the isthmus rhombencephali and that its cells do not migrate between existing cells of the mesencephalic tegmentum but first migrate ventralwards in a radial pattern and then rostrally towards their definite site. Numerous neurons of the basal mesencephalon and of the midline structures of the caudal mesencephalon are apparently derived from the region of the fovea isthmi.

The early neuronal organization predicts the path followed by some major axonal bundles in the embryonic brainstem.

In the embryonic CNS, preformed pathways precede the growth of axonal fasciculi [Katz M. J. and Lasek R. J. (1980) Cell Motil. 1, 141-157; Katz M. J. et al. (1980) Neuroscience 5, 821-833]. What are the developmental events that lead to the elaboration of these preformed pathways? To answer this question, we investigated the organization of the primitive neural tube and more particularly the arrangement of the early-generated cells using [3H]thymidine autoradiography or bromodeoxyuridine. Our data suggest that the position of early-generated cells might be involved in the setting of such pathways. In the brain stem of E12(0) (12 days and 0 h) and E12(15) rat embryos, the first-generated cells were organized into three longitudinal columns associated with glycoconjugate-rich extracellular spaces in the adjacent primitive marginal layer. Also, axons traced with 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) were contiguous to the early-generated cellular columns and represented the primordium of the medial longitudinal fasciculus, the lateral longitudinal tract and the mesencephalic trigeminal tract. Our results show a correlation between the organization of early-generated cells, likely neurons, and the pattern of extracellular spaces in the marginal layer where axons grow. It has been reported in the literature that neurons produce elements of the extracellular matrix such as growth-modulating molecules or space-creating molecules. We therefore suggest that the position of early-generated neurons could be involved in the elaboration of a template for the setting of some major longitudinal tracts during embryonic development of the brainstem.

Cost-effectiveness of screening compared to case-finding approaches to tuberculosis in long-term care facilities for the elderly.

BACKGROUND: To determine if the more interventionist approach of screening with the tuberculin test and chemoprophylaxis for high-risk positive reactors to control tuberculosis in long-term care facilities is cost-effective when compared to the case-finding and treatment approach. METHOD: A decision-analysis model was designed wherein systematic screening with the tuberculin skin test of all elderly patients newly admitted to facilities was compared to public health interventions restricted to investigation of cases and contacts with symptoms of tuberculosis after suspected exposure. Differences in life-years (LY), quality-adjusted life-years (QALY), cost per QALY and LY gained, annual cost per 1000 institutional patients were calculated in a health-care system perspective. RESULTS: In every situation analysed, screening and chemoprophylaxis were more effective. The cost per LY gained was within an acceptable range: $3437 per LY with a 0.6% nosocomial transmission rate and $7552 per LY when no nosocomial transmission was postulated. CONCLUSION: Screening plus chemoprophylaxis for high-risk reactors is more cost-effective than case-finding. This holds even when nosocomial transmission is assumed not to occur in facilities.

Interactions of copolymeric poly(glyceryl methacrylate)-collagen hydrogels with neural tissue: effects of structure and polar groups.

In a previous study we developed copolymeric glyceryl methacrylate-collagen hydrogels for implantation in surgical lesions of the rat brain. Such materials provide porous matrices that can serve as support systems for oriented growth of scar tissue and axonal growth. In the present work, we have investigated the effect of structural modifications (studied by mercury porosimetry) of polymeric matrices and the effect of polar groups on the response of the brain tissue. The findings show that the fractional porosity and the pore size distribution of matrices are critical for tissue ingrowth and that negative charges, i.e. carboxylic acid groups, incorporated in the polymer have a strong influence on reactive astrocytosis.

Intracerebral implantation of synthetic polymer/biopolymer matrix: a new perspective for brain repair.

Various poly (2-hydroxyethyl methacrylate)-collagen and poly (glyceryl methacrylate)-collagen composite hydrogels with varying porosities and cross-linking densities were implanted into the cortex of adult rat brains to provide mechanical guiding substrates for wound healing and tissue ingrowth. The hydrogels were well tolerated by the neural tissue. After 2 and 3 month, hyper- and macroporous hydrogels (poly(glyceryl methacrylate)) with interconnected channel systems were penetrated by neural tissue and elements of extracellular matrices, with differences in the degree and the topographic patterning of tissue ingrowth according to the type of samples. These differences were ascribed to the geometry, size of the pore interconnections and the mechanical properties of the polymers. Hyper- and microporous hydrogels (poly(2-hydroxyethyl methacrylate)) and hydrogels without collagen were not penetrated by the host tissue. The compatibility of the polymers with the neural tissue was also tested in vitro. This study suggests a new approach to repair brain lesions consisting of loss of tissue volume.

Induction of macrophage apoptosis by ceramic and polyethylene particles in vitro.

The purpose of this study was to investigate in vitro the presence of apoptotic cell death after macrophage stimulation with different ceramic (Al2O3 and ZrO2) and high density polyethylene (HDP) particles. We also analyzed the effects of particle size, concentration, and composition. The J774 mouse macrophage cell line was exposed to commercial particles of different sizes (up to 4.5 microm) and concentrations (up to 500 particles per macrophage). Fluorescence microscopy and DNA laddering were used to investigate the presence of apoptosis in cell cultures after 24 h of incubation. Fluorescence microscopy of propidium iodide stained cells showed two characteristic morphological features that occur in apoptotic cells, namely nuclear condensation and heterogeneity of stain uptake. The effect of ceramic particles on apoptotic nuclear morphology was size- and concentration-dependent and reached a plateau above 150 particles per macrophage at 1.3 microm. With regards to composition, we did not find any difference in cell morphology between Al2O3 and ZrO2. Ceramic and HDP particles induced DNA fragmentation into oligonucleosomes as evidenced by DNA laddering, another characteristic of apoptosis. The induction of DNA laddering was size- and concentration-dependent whereas particle composition (Al2O3 vs. ZrO2 and Al2O3 vs. HDP) had no effect. In conclusion, our results demonstrated that ceramic and HDP particles induce macrophage apoptotic cell death in vitro and open doors for possible modulation of debris-induced periprosthetic osteolysis.

Brain tissue and neural graft reactivity to the implantation of in situ self-assembled collagen matrices.

The extracellular matrices of living tissue provide scaffolding supports for cell migration and interaction during tissue remodelling and regeneration and therefore may also be relevant to processes of regeneration in the injured central nervous system. We implanted in artificially made cavities of the neostriatum or cortex of adult rats a fluid collagen gelling system into which fetal grafts from either the substantia nigra or cortex were introduced. The collagen polymerizes to form a fibrillar matrix (organogel) which restitutes a physical continuity to the neural tissue. The host tissue reaction consisted of the ingrowth of blood vessels, the migration of mesenchymatous cells, of reactive astrocytes and of microglia within the bioimplant which became the substrate of heterogeneous cell interactions. As a result, newly formed collagen and carbohydrate-rich materials were deposited upon the collagen matrix while the bioimplant underwent remodelling. After 2 months, the original matrix was replaced by a glial-mesenchymal matrix into which nerve fibers of the lesioned striatum regenerated. The neural transplants survived and differentiated according to the stability of collagen matrices. We conclude that a collagen gelling system can be used to introduce a scaffolding structure into open brain wounds, and suggest that instead of sealing off the lesion, the ensuing scarring process rather favors tissue repair by establishing a glial-mesenchymal matrix well-suited for inducing intrinsic and extrinsic (grafts) neural regeneration.

Collagen-cliondroitin-6-sulfate hydrogel implants in CNS lesion cavities favor glial repair, the differentiation of co-implanted neurons and the growth of axons.

Collagen chondroitin-6-sulfate hydrogels containing embryonic striatal neurons were implanted into premade brain cavities of the rat striatum. The bioimplant was progressively transformed into a new matrix mostly by the deposition of newly formed collagen and by the ingrowth of glial cells and glial cell processes. At two months, the new matrix has partly restructured the lesion cavity. Cells co-implanted with the hydrogels attached, survived and differentiated while nerve fibers of the host striatum grew into the biomatrix.

Calcium-binding proteins in primate cerebellum.

Single and double antigen localization procedures were used to study the distribution of the calcium-binding proteins calretinin, calbindin and parvalbumin in the cerebellum of the squirrel monkey (Saimiri sciureus). The immunostaining experiments have revealed that each of the three calcium-binding proteins occurred, either alone or in various combinations, in many neuronal types of the monkey cerebellum, including the Purkinje cells. Immunoreactivity for calbindin was detected in virtually all Purkinje cells, whereas immunoreactivity for calretinin and parvalbumin was encountered only in some subpopulations of Purkinje cells. In the vermal region, parvalbumin immunostaining appeared in the form of typical weak and strong alternating parasagittal bands. Calretinin immunoreactivity was found in virtually all neurons and fiber systems related to the granular layer, including the monodendritic cells, the granule cells and their parallel fibers, the Golgi and Lugaro cells and the mossy fibers. The Golgi cells also displayed calbindin and parvalbumin immunoreactivity. Parvalbumin was found to labeled both the climbing and mossy fibers, as well as the basket and stellate cells lying in the molecular layer. These results reveal that virtually all the different neuronal types in the primate cerebellum contain at least one of three calcium-binding proteins investigated in the present study. Furthermore, calretinin appears to be a particularly reliable molecular maker for all the neuronal elements associated with the granular layer in the primate cerebellum.