An humanized model to study homing and sequestration of transmission stages in the bone marrow.

Introduction: Recent evidence suggests that the bone marrow (BM) plays a key role in the diffusion of malaria by providing a "niche" for the maturation of the parasite gametocytes, responsible for human-to-mosquito transmission. Suitable humanized models to study the mechanisms of the interplay between the parasite and the human BM components are still missing.

Methods: We report a novel experimental system based on the infusion of immature gametocytes into immunocompromised mice carrying chimeric ectopic ossicles whose stromal and bone compartments derive from human osteoprogenitor cells.

Is There a Risk of Misinterpretation of Potassium Concentration from Undetectable Hemolysis Using a POCT Blood Gas Analyzer in the Emergency Department?

Background and Objectives: Hemolysis is reported to be present in up to 10% of blood gas specimens in the central lab; however, few data on the incidence of hemolysis using a point-of-care testing (POCT) blood gas analysis are available in the setting of the emergency department. The aims of this study were: (1) to analyze the prevalence of hemolysis in blood gas samples collected in the ED using a POCT device; and (2) to evaluate the impact of hemolysis on blood sample results and its clinical consequences. Materials and Methods: We collected 525 consecutive POCT arterial blood gas samples using syringes with electrolyte-balanced heparin within 3 different EDs in the metropolitan area of Rome.

Social influences in the digital era: When do people conform more to a human being or an artificial intelligence?

The spread of artificial intelligence (AI) technologies in ever-widening domains (e.g., virtual assistants) increases the chances of daily interactions between humans and AI.

Structural and Vibrational Properties of Amino Acids from Composite Schemes and Double-Hybrid DFT: Hydrogen Bonding in Serine as a Test Case.

The structures, relative stabilities, and vibrational wavenumbers of the two most stable conformers of serine, stabilized by the O-H···N, O-H···O═C and N-H···O-H intramolecular hydrogen bonds, have been evaluated by means of state-of-the-art composite schemes based on coupled-cluster (CC) theory. The so-called "cheap" composite approach (CCSD(T)/(CBS+CV)) allowed determination of accurate equilibrium structures and harmonic vibrational wavenumbers, also pointing out significant corrections beyond the CCSD(T)/cc-pVTZ level. These accurate results stand as a reference for benchmarking selected hybrid and double-hybrid, dispersion-corrected DFT functionals.

Phagocytosis and activation of bone marrow-derived macrophages by Plasmodium falciparum gametocytes.

Background: The innate immune response against various life cycle stages of the malaria parasite plays an important role in protection against the disease and regulation of its severity. Phagocytosis of asexual erythrocytic stages is well documented, but little and contrasting results are available about phagocytic clearance of sexual stages, the gametocytes, which are responsible for the transmission of the parasites from humans to mosquitoes. Similarly, activation of host macrophages by gametocytes has not yet been carefully addressed.

The bacterial protein CNF1 as a new strategy against Plasmodium falciparum cytoadherence.

Plasmodium falciparum severe malaria causes more than 400,000 deaths every year. One feature of P. falciparum-parasitized erythrocytes (pRBC) leading to cerebral malaria (CM), the most dangerous form of severe malaria, is cytoadherence to endothelium and blockage of the brain microvasculature.

Bicompartmental (uni plus patellofemoral) versus total knee arthroplasty: a match-paired study.

Background: Osteoarthritis (OA) of the knee, whether primary or post-traumatic, does not always involve all three compartments (tibiofemoral medial and lateral and the patellofemoral ones). Bicompartmental knee arthroplasty (BKA) was proposed as a good alternative to total knee arthroplasty when two of the three knee compartments were affected.

Materials And Methods: We performed a retrospective comparative study collecting all BKAs performed between March 2010 and January 2016.

Gametocytes of the Malaria Parasite Interact With and Stimulate Bone Marrow Mesenchymal Cells to Secrete Angiogenetic Factors.

The gametocytes of , responsible for the transmission of this malaria parasite from humans to mosquitoes, accumulate and mature preferentially in the human bone marrow. In the 10 day long sexual development of , the immature gametocytes reach and localize in the extravascular compartment of this organ, in contact with several bone marrow stroma cell types, prior to traversing the endothelial lining and re-entering in circulation at maturity. To investigate the host parasite interplay underlying this still obscure process, we developed an tridimensional co-culture system in a Matrigel scaffold with gametocytes and self-assembling spheroids of human bone marrow mesenchymal cells (hBM-MSCs).

A simple and predictive phenotypic High Content Imaging assay for Plasmodium falciparum mature gametocytes to identify malaria transmission blocking compounds.

Plasmodium falciparum gametocytes, specifically the mature stages, are the only malaria parasite stage in humans transmissible to the mosquito vector. Anti-malarial drugs capable of killing these forms are considered essential for the eradication of malaria and tools allowing the screening of large compound libraries with high predictive power are needed to identify new candidates. As gametocytes are not a replicative stage it is difficult to apply the same drug screening methods used for asexual stages.

A fast, non-invasive, quantitative staining protocol provides insights in Plasmodium falciparum gamete egress and in the role of osmiophilic bodies.

Background: Ability of Plasmodium falciparum gametocytes to become extracellular during gametogenesis in the mosquito midgut is a key step of the parasite life cycle. Reliable and quantitative measurement of the efficiency of gamete egress is currently constrained by the fact that this phenomenon is usually observed and quantified in vitro either by live microscopy, by statistically limited ultrastructural analysis or by surface antibody-based protocols which can interfere with this fast and complex cellular process.

Methods: A protocol was developed based on fluorescent wheat germ agglutinin (WGA) surface staining of erythrocytes containing mature P.

Feeling at home from arrival to departure: protein export and host cell remodelling during Plasmodium liver stage and gametocyte maturation.

Obligate intracellular pathogens actively remodel their host cells to boost propagation, survival, and persistence. Plasmodium falciparum, the causative agent of the most severe form of malaria, assembles a complex secretory system in erythrocytes. Export of parasite factors to the erythrocyte membrane is essential for parasite sequestration from the blood circulation and a major factor for clinical complications in falciparum malaria.

A Plasmodium falciparum screening assay for anti-gametocyte drugs based on parasite lactate dehydrogenase detection.

Objectives: Plasmodium gametocytes, responsible for malaria parasite transmission from humans to mosquitoes, represent a crucial target for new antimalarial drugs to achieve malaria elimination/eradication. We developed a novel colorimetric screening method for anti-gametocyte compounds based on the parasite lactate dehydrogenase (pLDH) assay, already standardized for asexual stages, to measure gametocyte viability and drug susceptibility.

Methods: Gametocytogenesis of 3D7 and NF54 Plasmodium falciparum strains was induced in vitro and asexual parasites were depleted with N-acetylglucosamine.

Early gametocytes of the malaria parasite Plasmodium falciparum specifically remodel the adhesive properties of infected erythrocyte surface.

In Plasmodium falciparum infections the parasite transmission stages, the gametocytes, mature in 10 days sequestered in internal organs. Recent studies suggest that cell mechanical properties rather than adhesive interactions play a role in sequestration during gametocyte maturation. It remains instead obscure how sequestration is established, and how the earliest sexual stages, morphologically similar to asexual trophozoites, modify the infected erythrocytes and their cytoadhesive properties at the onset of gametocytogenesis.

A switch in infected erythrocyte deformability at the maturation and blood circulation of Plasmodium falciparum transmission stages.

Achievement of malaria elimination requires development of novel strategies interfering with parasite transmission, including targeting the parasite sexual stages (gametocytes). The formation of Plasmodium falciparum gametocytes in the human host takes several days during which immature gametocyte-infected erythrocytes (GIEs) sequester in host tissues. Only mature stage GIEs circulate in the peripheral blood, available to uptake by the Anopheles vector.

Differential adhesive properties of sequestered asexual and sexual stages of Plasmodium falciparum on human endothelial cells are tissue independent.

The protozoan parasite Plasmodium falciparum, responsible for the most severe form of malaria, is able to sequester from peripheral circulation during infection. The asexual stage parasites sequester by binding to endothelial cell receptors in the microvasculature of various organs. P.

Gene expression in response to ionizing radiation and family history of gastric cancer.

Genes and molecular pathways involved in familial clustering of gastric cancer have not yet been identified. The purpose of the present study was to investigate gene expression changes in response to a cellular stress, and its link with a positive family history for this neoplasia. To this aim leukocytes of healthy first-degree relatives of gastric cancer patients and controls were challenged in vitro with ionizing radiation and gene expression evaluated 4 h later on microarrays with 1,800 cancer-related genes.

Protein export marks the early phase of gametocytogenesis of the human malaria parasite Plasmodium falciparum.

Despite over a century of study of malaria parasites, parts of the Plasmodium falciparum life cycle remain virtually unknown. One of these is the early gametocyte stage, a round shaped cell morphologically similar to an asexual trophozoite in which major cellular transformations ensure subsequent development of the elongated gametocyte. We developed a protocol to obtain for the first time highly purified preparations of early gametocytes using a transgenic line expressing a green fluorescent protein from the onset of gametocytogenesis.

A genomic glimpse of aminoacyl-tRNA synthetases in malaria parasite Plasmodium falciparum.

Background: Plasmodium parasites are causative agents of malaria which affects >500 million people and claims approximately 2 million lives annually. The completion of Plasmodium genome sequencing and availability of PlasmoDB database has provided a platform for systematic study of parasite genome. Aminoacyl-tRNA synthetases (aaRSs) are pivotal enzymes for protein translation and other vital cellular processes.

Revisiting the Plasmodium falciparum RIFIN family: from comparative genomics to 3D-model prediction.

Background: Subtelomeric RIFIN genes constitute the most abundant multigene family in Plasmodium falciparum. RIFIN products are targets for the human immune response and contribute to the antigenic variability of the parasite. They are transmembrane proteins grouped into two sub-families (RIF_A and RIF_B).

The role of osmiophilic bodies and Pfg377 expression in female gametocyte emergence and mosquito infectivity in the human malaria parasite Plasmodium falciparum.

Osmiophilic bodies are membrane-bound vesicles, found predominantly in Plasmodium female gametocytes, that become progressively more abundant as the gametocyte reaches full maturity. These vesicles lie beneath the subpellicular membrane of the gametocyte, and the release of their contents into the parasitophorous vacuole has been postulated to aid in the escape of gametocytes from the erythrocyte after ingestion by the mosquito. Currently, the only protein known to be associated with osmiophilic bodies in Plasmodium falciparum is Pfg377, a gametocyte-specific protein expressed at the onset of osmiophilic body development.

A 140-bp AT-rich sequence mediates positive and negative transcriptional control of a Plasmodium falciparum developmentally regulated promoter.

Little is known about the structure of malaria parasite gene promoters and how their activity is regulated during parasite development. We here report results of a functional study of the genomic flanking regions of the Plasmodium falciparum gametocyte-specific gene pfg27, whose promoter is inactive in asexual parasites and is specifically switched on at the onset of gametocytogenesis. Promoter deletion analysis with plasmids containing the green fluorescent protein reporter, conducted on asexual and sexual stage parasites of clone 3D7, showed that 140 bp immediately preceding the pfg27 transcription start sites are sufficient to achieve timing and specificity of gene expression comparable to those of the endogenous pfg27 gene.

Plasmodium falciparum: mRNA co-expression and protein co-localisation of two gene products upregulated in early gametocytes.

Genes encoding Plasmodium falciparum proteins Pfs16 and Pfpeg3/mdv1, specifically appearing in the parasitophorous vacuole of the early gametocytes, are upregulated at the onset of sexual differentiation. Analysis of asexual development in gametocyte producing and non-producing clones of P. falciparum indicated that these genes are also transcribed at a low level in asexual parasites, although their protein products are not detectable in these stages by immunofluorescence.

Functional genomics, new tools in malaria research.

The mosquito-transmitted unicellular parasite Plasmodium falciparum, the agent of malaria disease, still causes more than one million deaths every year in the tropical and subtropical areas of the world. New intervention strategies are needed to contrast the insurgence of resistance to effective drugs and insecticides. The complete annotated genomes of the human parasite P.