A systematic study of solution and processing parameters on nanofiber morphology using a new electrospinning apparatus

We assembled a new electrospinning apparatus and used poly(ethylene oxide) as a model polymer to perform a systematic study on the influence of solution and processing parameters on the morphology of electrospun nanofibers. Solution parameters studied were polymer concentration and molecular mass. The solvent used, 60 wt% water, 40 wt% ethanol, was the same throughout the study. Processing parameters analyzed were: solution feed rate, needle tip-collector distance and electrostatic potential difference between the needle and collector. Solution viscosity increased both with polymer concentration and molecular mass. Polymer concentration plays a decisive role on the outcome of the electrospinning process: a low concentration led to the formation of beaded fibers; an intermediate concentration yielded good quality fibers; a high concentration resulted in a bimodal size distribution and at even higher concentration a distributed deposition. Fiber diameter increased with polymer molecular mass and higher molecular masses are associated with a higher frequency of splaying events. Fiber diameter increased linearly with solution feed rate. While an increase in needle-collector distance represents a weaker electric field, a greater distance to be covered by the fibers and a longer flight time, presumably favoring the formation of thinner fibers, as solvent evaporation leads to a local increase of concentration and viscosity, viscoelastic forces opposing stretching caused an increase of fiber diameter with needle-collector distance. A higher voltage applied at the needle is associated with a higher charging of the polymer and a higher electrical current through it ultimately leading to incomplete solvent evaporation and merged fibers being produced. Controlling the charging of the polymer independently of the electric field strength was achieved by applying a voltage to the collector while distance and potential difference were kept constant. The increased electrostatic repulsion associated with an increase of the high voltage applied to the needle led to the disappearance of merged fibers.

In vivo imaging of mice infected with bioluminescent Trypanosoma cruzi unveils novel sites of infection

Background

The development of techniques that allow the imaging of animals infected with parasites expressing luciferase opens up new possibilities for following the fate of parasites in infected mammals.

Methods

D-luciferin potassium salt stock solution was prepared in phosphate-buffered saline (PBS) at 15 mg/ml. To produce bioluminescence, infected and control mice received an intraperitoneal injection of luciferin stock solution (150 mg/kg). All mice were immediately anesthetized with 2% isofluorane, and after 10 minutes were imaged. Ex vivo evaluation of infected tissues and organs was evaluated in a 24-well plate in 150 μg/ml D-luciferin diluted in PBS. Images were captured using the IVIS Lumina image system (Xenogen). Dissected organs were also evaluated by microscopy of hematoxylin-eosin stained sections.

Results

Here we describe the results obtained using a genetically modified Dm28c strain of T. cruzi expressing the firefly luciferase to keep track of infection by bioluminescence imaging. Progression of infection was observed in vivo in BALB/c mice at various intervals after infection with transgenic Dm28c-luc. The bioluminescent signal was immediately observed at the site of T. cruzi inoculation, and one day post infection (dpi) it was disseminated in the peritoneal cavity. A similar pattern in the cavity was observed on 7 dpi, but the bioluminescence was more intense in the terminal region of the large intestine, rectum, and gonads. On 14 and 21 dpi, bioluminescent parasites were also observed in the heart, snout, paws, hind limbs, and forelimbs. From 28 dpi to 180 dpi in chronically infected mice, bioluminescence declined in regions of the body but was concentrated in the gonad region. Ex vivo evaluation of dissected organs and tissues by bioluminescent imaging confirmed the in vivo bioluminescent foci. Histopathological analysis of dissected organs demonstrated parasite nests at the rectum and snout, in muscle fibers of mice infected with Dm28c-WT and with Dm28c-luc, corroborating the bioluminescent imaging.

Conclusion

Bioluminescence imaging is accurate for tracking parasites in vivo, and this methodology is important to gain a better understanding of the infection, tissue inflammation, and parasite biology regarding host cell interaction, proliferation, and parasite clearance to subpatent levels.

Combined C4d and CD3 immunostaining predicts immunoglobulin (Ig)A nephropathy progression

A number of molecules have been shown recently to be involved in the pathogenesis and progression of immunoglobulin (Ig)A nephropathy (IgAN). Among these, we have selected C4d (complement lectin pathway involvement), CD3 (T cell marker, traducing interstitial inflammation), transglutaminase 2 (TGase-2, involved in tissue fibrosis development) and p-extracelluar-regulated kinase (ERK)1/2 (protein kinase intracellular signaling molecule) to perform a panel of immunohistological biomarkers and assess its predictive value for disease progression. Immunohistochemical staining of these biomarkers was performed in paraffin sections from 74 renal biopsy cases with the clinical diagnosis of IgAN. Association between score analysis of these parameters and disease course was assessed through univariate and multivariate analysis, including baseline clinical and histological data. Univariate analysis showed that glomerular C4d, tubulointerstitial TGase2 and CD3 scores were associated with baseline proteinuria and disease progression. Multivariate analysis showed that only baseline estimated glomerular filtration rate (eGFR), C4d and CD3 were associated independently with progressive kidney disease (decline of at least 50% in the eGFR or progression to end-stage renal disease (ESRD) during the follow-up period). Establishing an accurate prediction model for IgAN progression is still a matter of research in clinical nephrology. The complement system, particularly lectin pathway activation, and T cell activation, have been shown previously to be potential modifiers of the disease course. Here we show that the combination of two histological biomarkers (C4d and CD3) can be a powerful predictor of IgAN progression and a potential useful tool for the clinical approach of this disease.

Biochemical analysis of proteins and lipids found in parasitophorous vacuoles containing Leishmania amazonensis

One fundamental step of Leishmania-macrophage interaction is the phase of parasite internalization through an endocytic process, with the formation of the parasitophorous vacuole (PV). The present study analyzed this process using two approaches. First, to investigate the host cell proteins which take part in this compartment, the macrophage surface was biotinilated and allowed to interact with both Leishmania forms, the PV was then isolated, and the biotinilated proteins were analyzed by Western blot. The results obtained showed that the isolated PV from macrophages infected for 60 min with infective promastigotes displayed high molecular weight proteins, 220 kDa and 180 kDa, contrary to the isolated PV obtained from amastigotes. The isolated PV from amastigotes, after 60 min interaction, displayed a faint, biotinilated protein profile, in contrast to the PV containing amastigote which, after 30 min interaction, displayed a strong protein profile in the range of 120 kDa and 40-60 kDa. The biotinilated protein profile may represent proteins distributed in the PV membrane and may also correspond to biotinilated proteins incorporated by the intracellular parasite, as observed by confocal microscopy. In a second approach, to investigate the PV phospholipid composition, macrophages were incubated with (32)P, allowed to interact with the parasites, and the isolated PV was then processed for phospholipid analysis by thin layer chromatography and scintillation counting. An increase in the levels of lysophosphatidylcholine was observed in infected macrophages. The isolated PV from infective promastigotes and amastigotes, after 60 min interaction, displayed high levels of phosphatidylcholine. Then the PV was ruptured and the intravacuolar parasite's (32)P phospholipid composition was analyzed by TLC; and labeling of the parasites was found, suggesting that phospholipids from the macrophage are transferred to the parasite. Taken together, the results obtained show that several proteins and phospholipids found in the plasma membrane of the macrophage are also found in the PV compartment.

Relationship between dental and periodontal health status and the salivary microbiome: bacterial diversity, co-occurrence networks and predictive models

The present study used 16S rRNA gene amplicon sequencing to assess the impact on salivary microbiome of different grades of dental and periodontal disease and the combination of both (hereinafter referred to as oral disease), in terms of bacterial diversity, co-occurrence network patterns and predictive models. Our scale of overall oral health was used to produce a convenience sample of 81 patients from 270 who were initially recruited. Saliva samples were collected from each participant. Sequencing was performed in Illumina MiSeq with 2 × 300 bp reads, while the raw reads were processed according to the Mothur pipeline. The statistical analysis of the 16S rDNA sequencing data at the species level was conducted using the phyloseq, DESeq2, Microbiome, SpiecEasi, igraph, MixOmics packages. The simultaneous presence of dental and periodontal pathology has a potentiating effect on the richness and diversity of the salivary microbiota. The structure of the bacterial community in oral health differs from that present in dental, periodontal or oral disease, especially in high grades. Supragingival dental parameters influence the microbiota’s abundance more than subgingival periodontal parameters, with the former making a greater contribution to the impact that oral health has on the salivary microbiome. The possible keystone OTUs are different in the oral health and disease, and even these vary between dental and periodontal disease: half of them belongs to the core microbiome and are independent of the abundance parameters. The salivary microbiome, involving a considerable number of OTUs, shows an excellent discriminatory potential for distinguishing different grades of dental, periodontal or oral disease; considering the number of predictive OTUs, the best model is that which predicts the combined dental and periodontal status.

Molecular and functional characterization of the first nucleobase transporter gene from African trypanosomes

African trypanosomes are unable to synthesize purines and depend upon purine nucleoside and nucleobase transporters to salvage these compounds from their hosts. To understand the crucial role of purine salvage in the survival of these parasites, a central objective is to identify and characterize all of the purine permeases that mediate uptake of these essential nutrients. We have cloned and functionally expressed in a purine nucleobase transport deficient strain of Saccharomyces cerevisiae a novel nucleobase transporter gene, TbNT8.1, from Trypanosoma brucei. The permease encoded by this gene mediates the uptake of hypoxanthine, adenine, guanine, and xanthine with Kms in the low micromolar range. The TbNT8.1 protein is a member of the equilibrative nucleoside transporter (ENT) family of permeases that occur in organisms as diverse as protozoa and mammals. TbNT8.1 is distinct from other ENT permeases that have been identified in trypanosomes in utilizing multiple purine nucleobases, rather than purine nucleosides, as substrates and is hence the first bona fide nucleobase permease identified in these parasites. Furthermore, unlike the mRNAs for other purine transporters, TbNT8.1 mRNA is significantly more abundant in insect stage procyclic forms than in mammalian stage bloodstream forms, and the TbNT8.1 permease thus may represent a major route for purine nucleobase uptake in procyclic trypanosomes.

Performance of SLEDAI-2K to detect a clinically meaningful change in SLE disease activity: a 36-month prospective cohort study of 334 patients

OBJECTIVE

The objective of this paper is to evaluate the performance of the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI-2K) in detecting clinically meaningful changes in SLE disease activity.

METHODS

A longitudinal cohort study was conducted of 334 SLE patients during a 36-month follow-up. At each outpatient visit, disease activity was scored using the Physician Global Assessment (PGA) and SLEDAI-2K. Correlations between PGA and SLEDAI-2K were assessed. A clinically meaningful change in SLE disease activity was defined as a ΔPGA ≥ 0.3 points from baseline. Performance of SLEDAI-2K in detecting a clinically meaningful worsening or improvement was tested using receiver operating characteristic (ROC) analysis.

RESULTS

Adjusted mean PGA and SLEDAI-2K scores presented a high correlation (rho = 0.824, p < 0.0005). In ROC analysis, a SLEDAI-2K variation presented an area under the curve (AUC) of 0.697 (95% confidence interval (CI) (0.628-0.766), p < 0.0005) to detect a clinically meaningful improvement, with a sensitivity of 28.8% for a SLEDAI-2K ≥ 4 reduction. The AUC to detect a clinically meaningful worsening was 0.877 (95% CI (0.822-0.932), p < 0.0005), with a sensitivity of 35.3%.

CONCLUSIONS

SLEDAI-2K has a limited ability to detect clinically meaningful changes in SLE disease activity, failing to identify almost two-thirds of cases judged as having a clinically meaningful improvement or worsening. There is a need for more sensitive SLE disease activity measures in clinical practice and research.

First-trimester Down syndrome screening: pregnant women's knowledge

OBJECTIVES

The primary aim of this study was to assess pregnant women's knowledge of first-trimester combined Down syndrome screening in a setting of required informed consent. As the secondary aim, we wanted to identify relevant differences in knowledge level among subgroups of pregnant women, including those informed in different ways about prenatal examinations.

METHODS

Data stem from a population-based cross-sectional questionnaire study including 15 multiple-choice questions assessing knowledge of different aspects of screening. Included were 6427 first-trimester pregnant women from three Danish obstetric departments offering prenatal screening free of charge. Both participants and non-participants in the screening program were included. The results are based on 4095 responders (64%). Differences between subgroups were examined using chi-squared tests and logistic regression analysis. Estimates are stated with 95% CI.

RESULTS

The majority of the participants (87.6 (86.6-88.6)% to 92.6 (91.7-93.3)%) correctly identified the test concept and the main condition being screened for. Fewer participants (16.4 (15.3-17.6)% to 43.3 (41.8-44.8)%) correctly recognized test accuracy and the potential risk of adverse findings other than Down syndrome. Knowledge level was positively associated with length of education (adjusted ORs 1.0 (0.8-1.4) to 3.9 (2.4-6.4)) and participation in the screening program (adjusted OR 0.9 (0.6-1.3) to 5.9 (3.9-8.8)). Participation in an individual information session was weakly associated with more knowledge.

CONCLUSION

The majority of the pregnant women correctly identified the test concept and the main condition being screened for. The pregnant women were found less knowledgeable on test accuracy and drawbacks.

Aberrant signaling in T-cell acute lymphoblastic leukemia: biological and therapeutic implications

T-cell acute lymphoblastic leukemia (T-ALL) is a biologically heterogeneous disease with respect to phenotype, gene expression profile and activation of particular intracellular signaling pathways. Despite very significant improvements, current therapeutic regimens still fail to cure a portion of the patients and frequently implicate the use of aggressive protocols with long-term side effects. In this review, we focused on how deregulation of critical signaling pathways, in particular Notch, PI3K/Akt, MAPK, Jak/STAT and TGF-beta, may contribute to T-ALL. Identifying the alterations that affect intracellular pathways that regulate cell cycle and apoptosis is essential to understanding the biology of this malignancy, to define more effective markers for the correct stratification of patients into appropriate therapeutic regimens and to identify novel targets for the development of specific, less detrimental therapies for T-ALL.

Bioluminescent imaging of Trypanosoma cruzi infection in Rhodnius prolixus

Background

Usually the analysis of the various developmental stages of Trypanosoma cruzi in the experimentally infected vertebrate and invertebrate hosts is based on the morphological observations of tissue fragments from animals and insects. The development of techniques that allow the imaging of animals infected with parasites expressing luciferase open up possibilities to follow the fate of bioluminescent parasites in infected vectors.

Methods

D-luciferin (60 μg) was injected into the hemocoel of the whole insect before bioluminescence acquisition. In dissected insects, the whole gut was incubated with D-luciferin in PBS (300 μg/ml) for ex vivo bioluminescence acquisition in the IVIS® Imaging System, Xenogen.

Results

Herein, we describe the results obtained with the luciferase gene integrated into the genome of the Dm28c clone of T. cruzi, and the use of these parasites to follow, in real time, the infection of the insect vector Rhodnius prolixus, by a non- invasive method. The insects were evaluated by in vivo bioluminescent imaging on the feeding day, and on the 7 th, 14 th, 21 st and 28 th days after feeding. To corroborate the bioluminescent imaging made in vivo, and investigate the digestive tract region, the insects were dissected. The bioluminescence emitted was proportional to the number of protozoans in regions of the gut. The same digestive tracts were also macerated to count the parasites in distinct morphological stages with an optical microscope, and for bioluminescence acquisition in a microplate using the IVIS® Imaging System. A positive correlation of parasite numbers and bioluminescence in the microplate was obtained.

Conclusions

This is the first report of bioluminescent imaging in Rhodnius prolixus infected with trypomastigotes of the Dm28c-luc stable strain, expressing firefly luciferase. In spite of the distribution limitations of the substrate (D-luciferin) in the insect body, longitudinal evaluation of infected insects by bioluminescent imaging is a valuable tool. Bioluminescent imaging of the digestive tract infected with Dm28c-luc is highly sensitive and accurate method to track the fate of the parasite in the vector, in the crop, intestine and rectum. This methodology is useful to gain a better understanding of the parasite – insect vector interactions.

The future water environment--using scenarios to explore the significant water management challenges in England and Wales to 2050

Society gets numerous benefits from the water environment. It is crucial to ensure that water management practices deliver these benefits over the long-term in a sustainable and cost-effective way. Currently, hydromorphological alterations and nutrient enrichment pose the greatest challenges in European water bodies. The rapidly changing climatic and socio-economic boundary conditions pose further challenges to water management decisions and the achievement of policy goals. Scenarios are a strategic tool useful in conducting systematic investigations of future uncertainties pertaining to water management. In this study, the use of scenarios revealed water management challenges for England and Wales to 2050. A set of existing scenarios relevant to river basin management were elaborated through stakeholder workshops and interviews, relying on expert knowledge to identify drivers of change, their interdependencies, and influence on system dynamics. In a set of four plausible alternative futures, the causal chain from driving forces through pressures to states, impacts and responses (DPSIR framework) was explored. The findings suggest that scenarios driven by short-term economic growth and competitiveness undermine current environmental legislative requirements and exacerbate the negative impacts of climate change, producing a general deterioration of water quality and physical habitats, as well as reduced water availability with adverse implications for the environment, society and economy. Conversely, there are substantial environmental improvements under the scenarios characterised by long-term sustainability, though achieving currently desired environmental outcomes still poses challenges. The impacts vary across contrasting generic catchment types that exhibit distinct future water management challenges. The findings suggest the need to address hydromorphological alterations, nutrient enrichment and nitrates in drinking water, which are all likely to be exacerbated in the future. Future-proofing river basin management measures that deal with these challenges is crucial moving forward. The use of scenarios to future-proof strategy, policy and delivery mechanisms is discussed to inform next steps.

Living versus cadaveric-donor renal transplant recipients: a comparison on sexual function

Erectile dysfunction is experienced by 50% of men with end-stage renal disease (ESRD) and uremia. The origin of this dysfunction is multifactorial. The aim of this study was to compare living donor versus cadaveric donor transplant recipients regarding male sexual function. Seventy-seven sexually active male kidney transplant recipients (44 from living donors; 33 from cadaveric donors) were randomly selected from our single-center prospective database of 2016 renal transplants. Epidemiological and clinical data were collected between June 2010 and June 2011. Male sexual function was evaluated with the International Index of Erectile Function questionnaire (IIEF-15). We assessed the prevalence of male sexual dysfunction according to established cutoff points for each of the IIEF-15 domains. Mann-Whitney and Pearson's chi- square statistical tests were used to compare continuous and categorical variables, respectively. The median age at the time of completion of the questionnaires was 43 and 51 years (P = .003) with median times from transplantation was of 36 and 42 months for living donor and cadaveric donor recipients, respectively (P = .31). Median durations of ESRD before surgery were 17.5 and 57 months for living donor and cadaveric donor recipients, respectively (P < .001). Living donor and cadaveric donor recipients had median creatinine clearance values of 55 and 57 mL/min, respectively (P = .44). Median time after renal transplantation for first sexual intercourse was 1 and 2 months for living donor and cadaveric donor recipients, respectively (P = .35). Median body mass indices for living donor and cadaveric donor recipients were 24.8 and 24, respectively (P = .31). Regarding sexual function domains, there were significant differences only for intercourse satisfaction. In our cohort, living donor recipients tended to be younger, have shorter time of ESRD, and less incidence of hypertension or diabetes mellitus but with greater tobacco use. In conclusion, living donor transplantation exerted a favorable impact on sexual function.

Identification and functional characterization of a novel arginine/ornithine transporter, a member of a cationic amino acid transporter subfamily in the Trypanosoma cruzi genome

Background

Trypanosoma cruzi, the etiological agent of Chagas disease, is auxotrophic for arginine. It obtains this amino acid from the host through transporters expressed on the plasma membrane and on the membranes of intracellular compartments. A few cationic amino acid transporters have been characterized at the molecular level, such as the novel intracellular arginine/ornithine transporter, TcCAT1.1, a member of the TcCAT subfamily that is composed of four almost identical open reading frames in the T. cruzi genome.

Methods

The functional characterization of the TcCAT1.1 isoform was performed in two heterologous expression systems. TcCAT subfamily expression was evaluated by real-time PCR in polysomal RNA fractions, and the cellular localization of TcCAT1.1 fused to EGFP was performed by confocal and immunoelectron microscopy.

Results

In the S. cerevisiae expression system, TcCAT1.1 showed high affinity for arginine (K_m = 0.085 ± 0.04 mM) and low affinity for ornithine (K_m = 1.7 ± 0.2 mM). Xenopus laevis oocytes expressing TcCAT1.1 showed a 7-fold increase in arginine uptake when they were pre-loaded with arginine, indicating that transport is enhanced by substrates on the trans side of the membrane (trans-stimulation). Oocytes that were pre-loaded with [³H]-arginine displayed a 16-fold higher efflux of [³H]-arginine compared with that of the control. Analysis of polysomal RNA fractions demonstrated that the expression of members of the arginine transporter TcCAT subfamily is upregulated under nutritional stress and that this upregulation precedes metacyclogenesis. To investigate the cellular localization of the transporter, EGFP was fused to TcCAT1.1, and fluorescence microscopy and immunocytochemistry revealed the intracellular labeling of vesicles in the anterior region, in a network of tubules and vesicles.

Conclusions

TcCAT1.1 is a novel arginine/ornithine transporter, an exchanger expressed in intracellular compartments that is physiologically involved in arginine homeostasis throughout the T. cruzi life cycle. The properties and estimated kinetic parameters of TcCAT1.1 can be extended to other members of the TcCAT subfamily.

Redistribution of plasma-membrane surface molecules during formation of the Leishmania amazonensis-containing parasitophorous vacuole

Leishmania amazonensis presents two developmental stages that gain access to the host macrophage through phagocytosis. The protozoan resides in a membrane-bound compartment, the parasitophorous vacuole (PV), which can fuse with the endocytic system. For evaluation of the parasite/host-cell interaction process and of PV biogenesis, the two parasite forms or host-cell membrane whose surface had previously been labeled with specific probes for lipids, proteins, and sialoglycoconjugates were allowed to interact for periods varying from 5 to 15 min for adhesion and from 30 to 60 min for PV formation. The fate of fluorescent probes was followed by confocal laser scanning microscopy. In host cells previously labeled with PKH26, DTAF and FITC-thiosemicarbazide, which label membrane lipids, proteins, and sialoglycoconjugates, respectively, interaction with both protozoan forms revealed that adhesion to the macrophage was sufficient for labeling of the parasite surface. In addition, recently formed PVs displayed strongly labeled intravacuolar parasites, except for amastigote-macrophage interaction in a DTAF-labeled macrophage that displayed slight labeling of intravacuolar parasites, with the membrane lining the PV evidently being stained. Therefore, the vacuole modulation presents some particularities such that different host-cell membrane components may be selected, depending on the protozoan form involved. Thereafter, amastigotes labeled with the probes mentioned above displayed a diffuse labeling pattern after interaction with unlabeled macrophages, suggesting the spreading of Leishmania surface molecules during the initial parasite-invasion stages. In particular, intravacuolar DTAF-labeled amastigotes showed a delineating halo around the PV, with the intravacuolar parasite being partially labeled. Promastigotes could not be labeled with 5-(4,6-dichlorotriazinyl)aminofluorescein (DTAF) or with fluorescein-5-thiosemicarbazide, but promastigotes labeled with PKH26 lost the fluorescent probe during the invasion process such that slightly labeled promastigotes were seen inside the PV. These observations indicate the existence of a dynamic process of exchange of membrane-associated glycoproteins and lipids between the parasite and the host cell.