Exploring the potential of Eu3+ and Mn4+ activated LaAlO3 phosphors as red and far-red emitters for horticulture lighting

The development of efficient red and far-red emitters, for efficient plant absorption in the Photosynthetically Active Radiation (PAR) region, holds significance in contemporary plant growth control. This study focuses on the synthesis and characterization of LaAlO3 as a host material, doped with Eu3+ and Mn4+ ions, using a solid-state reaction method. The investigation encompasses the creation and analysis of both single-doped and co-doped samples, employing techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectroscopy. XRD analysis consistently confirmed the perovskite-like structure of all samples, devoid of detectable impurities or major structural changes due to doping. SEM images revealed a uniform distribution of regularly shaped particles for the co-doped sample. The PL spectroscopy showed that the doping led to strong photoluminescence, with the co-doped sample exhibiting the intensity of each of the ions independently neither exhibiting quenching nor energy transfer mechanisms. The excitation spectrum of Eu3+ exhibited a broad charge transfer band at approximately 328 nm, coupled with characteristic f-f excitation bands. On the other hand, the Mn4+ ion's excitation spectrum featured transitions from ground state (4A2g) electrons excited to higher excited states (4T1g, 2T2g, and 4T2g) centered at 350 nm and within the region 250-550 nm. The co-doped sample was excited at a common excitation wavelength of 460 nm and underwent an in-depth examination of its photoluminescent properties, including decay curves analysis and time dependence also. The results from this study suggest that the synthesized phosphor materials exhibit substantial potential for diverse applications, including but not limited to solid-state lighting for efficient plant growth.

In Silico, In Vitro, and Pharmacokinetic Studies of UBMC-4, a Potential Novel Compound for Treating against Trypanosoma cruzi

The lack of therapeutic alternatives for the treatment of Chagas disease, a neglected disease, drives the discovery of new drugs with trypanocidal activity. Consequently, we conducted in vitro studies using UBMC-4, a potential Trypanosoma cruzi AKT-like pleckstrin homology (PH) domain inhibitory compound found using bioinformatics tools. The half effective concentration (EC50) on intracellular amastigotes was determined at 1.85 ± 1 μM showing low cytotoxicity (LC50) > 40 μM on human cell lines tested. In order to study the lethal effect caused by the compound on epimastigotes, morphological changes were assessed by scanning and transmission electron microscopy. Progressive alterations such as flagellum inactivation, cell size reduction, nuclear structure alteration, condensation of chromatin towards the nuclear periphery, vacuole formation, and mitochondrial swelling with kinetoplast integrity loss were evidenced. In addition, apoptosis-like markers in T. cruzi were assessed by flow cytometry, demonstrating that the effect of UBMC-4 on T. cruzi AKT-like kinase reduced the tolerance to nutritional stress-triggered, apoptosis-like events, including DNA fragmentation, mitochondrial damage, and loss of plasma membrane integrity. After this, UBMC-4 was formulated for oral administration and pharmacokinetics were analyzed in a mouse model. Finally, upon oral administration of 200 mg/kg in mice, we found that a UBMC-4 plasma concentration remaining in circulation beyond 24 h after administration is well described by the two-compartment model. We conclude that UBMC-4 has an effective trypanocidal activity in vitro at low concentrations and this effect is evident in T. cruzi cell structures. In mice, UBMC-4 was well absorbed and reached plasma concentrations higher than the EC50, showing features that would aid in developing a new drug to treat Chagas disease.

The terpenic diamine GIB24 inhibits the growth of Trypanosoma cruzi epimastigotes and intracellular amastigotes, with proteomic analysis of drug-resistant epimastigotes

The effect of N-geranyl-ethane-1,2-diamine dihydochloride (GIB24), a synthetic diamine, was assayed against different developmental forms of the parasitic protozoan Trypanosoma cruzi (strain Dm28c). The compound was effective against culture epimastigote forms (IC₅₀/24h = 5.64 μM; SI = 16.4) and intracellular amastigotes (IC₅₀/24h = 12.89 μM; SI = 7.18), as detected by the MTT methodology and by cell counting, respectively. Incubation of epimastigotes for 6h with 6 μM GIB24 (IC₅₀/24h value) resulted in significant dissipation of the mitochondrial membrane potential, prior to permeabilization of the plasma membrane. Rounded epimastigotes with cell size reduction were observed by scanning electron microscopy. These morpho-physiological changes induced by GIB24 suggest an incidental death process. Treatment of infected Vero cells did not prevent the intracellular amastigotes from completing the intracellular cycle. However, there was a decrease in the number of released parasites, increasing the ratio amastigotes/trypomastigotes. Proteomic analysis of 15 μM GIB24 resistant epimastigotes indicated that the compound acts mainly on mitochondrial components involved in the Krebs cycle and in maintaining the oxidative homeostasis of the parasites. Our data suggest that GIB24 is active against the main morphological forms of T. cruzi.

Treatment of Trypanosoma cruzi with 2-bromopalmitate alters morphology, endocytosis, differentiation and infectivity

Background

The palmitate analogue 2-bromopalmitate (2-BP) is a non-selective membrane tethered cysteine alkylator of many membrane-associated enzymes that in the last years emerged as a general inhibitor of protein S-palmitoylation. Palmitoylation is a post-translational protein modification that adds palmitic acid to a cysteine residue through a thioester linkage, promoting membrane localization, protein stability, regulation of enzymatic activity, and the epigenetic regulation of gene expression. Little is known on such important process in the pathogenic protozoan Trypanosoma cruzi, the etiological agent of Chagas disease.

Results

The effect of 2-BP was analyzed on different developmental forms of Trypanosoma cruzi. The IC₅₀/48 h value for culture epimastigotes was estimated as 130 μM. The IC₅₀/24 h value for metacyclic trypomastigotes was 216 nM, while for intracellular amastigotes it was 242 μM and for cell derived trypomasigotes was 262 μM (IC₅₀/24 h). Our data showed that 2-BP altered T. cruzi: 1) morphology, as assessed by bright field, scanning and transmission electron microscopy; 2) mitochondrial membrane potential, as shown by flow cytometry after incubation with rhodamine-123; 3) endocytosis, as seen after incubation with transferrin or albumin and analysis by flow cytometry/fluorescence microscopy; 4) in vitro metacyclogenesis; and 5) infectivity, as shown by host cell infection assays. On the other hand, lipid stress by incubation with palmitate did not alter epimastigote growth, metacyclic trypomastigotes viability or trypomastigote infectivity.

Conclusion

Our results indicate that 2-BP inhibits key cellular processes of T. cruzi that may be regulated by palmitoylation of vital proteins and suggest a metacyclic trypomastigote unique target dependency during the parasite development.

Electronic supplementary material

The online version of this article (10.1186/s12860-018-0170-3) contains supplementary material, which is available to authorized users.

Subcellular localisation of FLAG tagged enzymes of the dynamic protein S-palmitoylation cycle of Trypanosoma cruzi epimastigotes

Dynamic S-palmitoylation of proteins is the addition of palmitic acid by zDHHC palmitoyl transferases (PATs) and depalmitoylation by palmitoyl protein thioesterases (PPTs). A putative PAT (TcPAT1) has been previously identified in Trypanosoma cruzi, the etiological agent of Chagas disease. Here we analyse other 14 putative TcPATs and 2 PPTs in the parasite genome. T. cruzi cell lines expressing TcPATs and TcPPTs plus a FLAG tag at the C terminus were produced for most enzymes, with positive detection by indirect immunofluorescence. Overexpressed TcPATs were mostly found as single spots at the parasite anterior end, while the TcPPTs were dispersed throughout the parasite body.

Fasting and glucose induced thermogenesis in response to three ambient temperatures: a randomized crossover trial in the metabolic syndrome

BACKGROUND/OBJECTIVES

Cold exposure increases thermogenesis and could improve insulin sensitivity. We hypothesized a blunted response in the metabolic syndrome (MetS).

SUBJECTS/METHODS

Twenty older adults 59 ± 10.4 years (with MetS, MetS+, n = 9; without MetS, MetS-, n = 11) completed a randomized crossover design of 3.5 h exposures to 20, 25 and 27 °C on three visits. After an hour's rest at the desired temperature, resting metabolic rate (RMR), respiratory quotient (RQ), forearm to fingertip gradients (FFG), and in the ear temperature (IET) were measured over 30 min. An oral glucose tolerance test followed, and serial measurements were continued for 2 h. Venous blood was sampled for clinical chemistry, irisin, and fibroblast growth factor 21(FGF21). A mixed model ANCOVA adjusted data for age, gender, fat mass, fat-free mass and seasonality.

RESULTS

There was a significant MetS×temperature interaction where adjusted RMR was significantly higher in MetS+ compared to MetS- by 12% at 20 °C and by 6% at 25 °C, but similar at 27 °C. FFG increased and IET decreased with decreasing temperature to the same extent in both groups. Fasting irisin and FGF21 did not vary with temperature but the former was significantly higher in MetS-. Adjusted postprandial RQ and insulin to glucose ratios were significantly higher at 20 °C relative to 25 °C. Partial correlation analysis of differences between 27 and 20 °C indicated significant positive relationships between fasting as well as postprandial RQ and the respective changes in irisin and FGF21.

CONCLUSIONS

There could be an upward shift of the TNZ in MetS+, but this needs reevaluation.

Highly efficient upconversion of Er3+ in Yb3+ codoped non-cytotoxic strontium lanthanum aluminate phosphor for low temperature sensors

Er³⁺ and Er³⁺/Yb³⁺ melilite-based SrLaAl₃O₇ (SLA) phosphors were synthesized by a facile Pechine method. The differences in emission intensities of ⁴I_13/2 → ⁴I_15/2 transition in NIR region when excited with Ar⁺ and 980 nm lasers were explained in terms of energy transfer mechanisms. Temperature and power dependence of upconversion bands in the visible region centered at 528, 548 and 660 nm pertaining to ²H_11/2, ⁴S_3/2 and ⁴F_9/2 → ⁴I_15/2 transitions were investigated. Fluorescence intensity ratio (FIR) technique was used to explore temperature sensing behaviour of the thermally coupled levels ²H_11/2/⁴S_3/2 of Er³⁺ ions in the phosphors within the temperature range 14–300 K and the results were extrapolated up to 600 K. Anomalous intensity trend observed in Er³⁺ doped SLA phosphor was discussed using energy level structure. Cytotoxicity of phosphors has been evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in Bluegill sunfish cells (BF-2). The non-cytotoxic nature and high sensitivity of the present phosphors pay a way for their use in vitro studies and provide potential interest as a thermo graphic phosphor at the contact of biological products.

Biological activity of the azlactone derivative EPA-35 against Trypanosoma cruzi

Chagas disease, caused by Trypanosoma cruzi, affects six to seven million people worldwide. Treatment is based on benznidazole, producing several side effects and debatable efficacy, highlighting the need for new alternative drugs. We investigated the activity of four C-4 functionalized azlactone derivatives (EPA-27, EPA-35, EPA-63 and EPA-91) as potential T. cruzi inhibitors. Screening with epimastigotes indicated EPA-35 as the best compound (IC50/24 h: 33 μM). This compound was 14.1 times more potent against intracellular amastigotes (IC50/24 h: 2.34 μM). Treatment of infected Vero cells for 72 h (up to 30 μM EPA-35) resulted in a dose-dependent decrease in number of trypomastigotes and amastigotes released in the supernatant, but the amastigote/trypomastigote ratio remained constant, indicating that amastigote growth was disturbed, but cell differentiation was unaffected. Analysis of treated epimastigotes by flow cytometry indicated that the plasma membrane remained intact, but there was a significant decrease in mitochondrial membrane potential. The pattern of cell distribution in the cell cycle stages (G1, G2, M) was unaltered in treated epimastigotes, indicating a trypanocidal rather than a trypanostatic activity. Scanning electron microscopy and flow cytometry showed epimastigotes with a round shape and decrease in cell size. Taken together, our data indicate that the EPA-35 is effective against T. cruzi. Synthetic transformation of EPA-35 into other derivatives may provide promising compounds for further evaluation against this parasite.

Knockout of the gamma subunit of the AP-1 adaptor complex in the human parasite Trypanosoma cruzi impairs infectivity and differentiation and prevents the maturation and targeting of the major protease cruzipain

The AP-1 Adaptor Complex assists clathrin-coated vesicle assembly in the trans-Golgi network (TGN) of eukaryotic cells. However, the role of AP-1 in the protozoan Trypanosoma cruzi-the Chagas disease parasite-has not been addressed. Here, we studied the function and localization of AP-1 in different T. cruzi life cycle forms, by generating a gene knockout of the large AP-1 subunit gamma adaptin (TcAP1-γ), and raising a monoclonal antibody against TcAP1-γ. Co-localization with a Golgi marker and with the clathrin light chain showed that TcAP1-γ is located in the Golgi, and it may interact with clathrin in vivo, at the TGN. Epimastigote (insect form) parasites lacking TcAP1-γ (TcγKO) have reduced proliferation and differentiation into infective metacyclic trypomastigotes (compared with wild-type parasites). TcγKO parasites have also displayed significantly reduced infectivity towards mammalian cells. Importantly, TcAP1-γ knockout impaired maturation and transport to lysosome-related organelles (reservosomes) of a key cargo-the major cysteine protease cruzipain, which is important for parasite nutrition, differentiation and infection. In conclusion, the defective processing and transport of cruzipain upon AP-1 ablation may underlie the phenotype of TcγKO parasites.

The impact of cholecalciferol supplementation on the systemic inflammatory profile: a systematic review and meta-analysis of high-quality randomized controlled trials

Causal links between vitamin D status [25(OH)D] and systemic inflammation were examined through a systematic review of randomized controlled trials (RCTs). Selected RCTs were ⩾12 weeks, conducted in adults free of acute inflammatory disease, and of high-quality (Jadad score ⩾3). Of 14 studies that met our criteria, 9 studies (15 study arms) permitted extraction of data. There was no effect on the weighted mean difference (WMD) of IL-6 (WMD (95% confidence interval)=0.1, (-0.166, 0.366) pg/ml, P=0.462) or C-reactive protein (CRP) (WMD=-0.324, (-1.007, 0.359) mg/l, P=0.352). Subgroup analyses of trials achieving ⩾80 nmol/l indicated a trend for lower CRP (WMD=-0.834, (-1.726, 0.058) mg/l, P=0.067), however heterogeneity was significant (I²=66.7%, P=0.017). Studies employing a low dose (<1000 IU/d) showed increased CRP (WMD=0.615, (0.132, 1.098), P=0.013). In contrast, ⩾1000 IU/d had a favourable effect on CRP (WMD=-0.939, (-1.805, -0.073), P=0.034) but heterogeneity was significant (I²=61.3%, P=0.017). Meta-regression indicated that older age predicted a significant decrease in IL-6 (β=-0.02, (-0.034, -0.006) pg/ml, P=0.013) and CRP (β=-0.06, (-0.103, -0.017), P=0.01), whereas a greater percentage of females (β=0.027, (0.011, 0.044), P=0.004) and longer study duration independently predicted a higher WMD for CRP (β=0.049, (0.018, 0.079), P=0.005). Available high-quality RCTs did not support a beneficial effect of cholecalciferol on systemic IL-6 and CRP. Future studies should consider the confounding effects of age, gender and study duration, while possibly targeting an achieved 25(OH)D ⩾80 nmol/l.

Linalool, a Piper aduncum essential oil component, has selective activity against Trypanosoma cruzi trypomastigote forms at 4°C

BACKGROUND

Recent studies showed that essential oils from different pepper species (Piper spp.) have promising leishmanicidal and trypanocidal activities.

OBJECTIVES

In search for natural compounds against Trypanosoma cruzi, different forms of the parasite were incubated for 24 h at 28ºC or 4ºC with Piper aduncum essential oil (PaEO) or its main constituents linalool and nerolidol.

METHODS

PaEO chemical composition was obtained by GC-MS. Drug activity assays were based on cell counting, MTT data or infection index values. The effect of PaEO on the T. cruzi cell cycle and mitochondrial membrane potential was evaluated by flow cytometry.

FINDINGS

PaEO was effective against cell-derived (IC50/24 h: 2.8 μg/mL) and metacyclic (IC50/24 h: 12.1 μg/mL) trypomastigotes, as well as intracellular amastigotes (IC50/24 h: 9 μg/mL). At 4ºC - the temperature of red blood cells (RBCs) storage in blood banks - cell-derived trypomastigotes were more sensitive to PaEO (IC50/24 h = 3.8 μg/mL) than to gentian violet (IC50/24 h = 24.7 mg/mL). Cytotoxicity assays using Vero cells (37ºC) and RBCs (4ºC) showed that PaEO has increased selectivity for cell-derived trypomastigotes. Flow cytometry analysis showed that PaEO does not affect the cell cycle of T. cruzi epimastigotes, but decreases their mitochondrial membrane potential. GC-MS data identified nerolidol and linalool as major components of PaEO, and linalool had trypanocidal effect (IC50/24 h: 306 ng/mL) at 4ºC.

MAIN CONCLUSION

The trypanocidal effect of PaEO is likely due to the presence of linalool, which may represent an interesting candidate for use in the treatment of potentially contaminated RBCs bags at low temperature.

Conservation and divergence within the clathrin interactome of Trypanosoma cruzi

Trypanosomatids are parasitic protozoa with a significant burden on human health. African and American trypanosomes are causative agents of Nagana and Chagas disease respectively, and speciated about 300 million years ago. These parasites have highly distinct life cycles, pathologies, transmission strategies and surface proteomes, being dominated by the variant surface glycoprotein (African) or mucins (American) respectively. In African trypanosomes clathrin-mediated trafficking is responsible for endocytosis and post-Golgi transport, with several mechanistic aspects distinct from higher organisms. Using clathrin light chain (TcCLC) and EpsinR (TcEpsinR) as affinity handles, we identified candidate clathrin-associated proteins (CAPs) in Trypanosoma cruzi; the cohort includes orthologs of many proteins known to mediate vesicle trafficking, but significantly not the AP-2 adaptor complex. Several trypanosome-specific proteins common with African trypanosomes, were also identified. Fluorescence microscopy revealed localisations for TcEpsinR, TcCLC and TcCHC at the posterior region of trypomastigote cells, coincident with the flagellar pocket and Golgi apparatus. These data provide the first systematic analysis of clathrin-mediated trafficking in T. cruzi, allowing comparison between protein cohorts and other trypanosomes and also suggest that clathrin trafficking in at least some life stages of T. cruzi may be AP-2-independent.

Hemispheric asymmetries in subcortical visual and auditory relay structures in congenital deafness

Neuroplasticity - the capacity of the brain to change as a response to internal and external pressures - has been studied from a number of different perspectives. Perhaps one of the most powerful models is the study of populations that have been congenitally deprived of a sense. It has been shown that the right Auditory Cortex (AC) of congenitally deaf humans is neuroplastically modified in order to represent visual properties of a stimulus. One unresolved question is how this visual information is routed to the AC of congenitally deaf individuals. Here, we performed volumetric analysis of subcortical auditory and visual brains regions - namely the thalamus (along with three thalamic nuclei: the pulvinar, the lateral geniculate nucleus and the medial geniculate nucleus), and the inferior and superior colliculi - in deaf and hearing participants in order to identify which structures may be responsible for relaying visual information toward the altered AC. Because there is a hemispheric asymmetry in the neuroplastic changes observed in the AC of the congenitally deaf, we reasoned that subcortical structures that also showed a similar asymmetry in their total volume could have been enlisted in the effort of relaying visual information to the neuroplastically altered right AC. We show that for deaf, but not for hearing individuals, the right thalamus, right lateral geniculate nucleus and right inferior colliculus are larger than their left counterparts. These results suggest that these subcortical structures may be responsible for rerouting visual information to the AC in congenital deafness.

Development of a magnetic separation method to capture sepsis associated bacteria in blood

Bloodstream infections are important public health problems, associated with high mortality due to the inability to detect the pathogen quickly in the early stages of infection. Such inability has led to a growing interest in the development of a rapid, sensitive, and specific assay to detect these pathogens. In an effort to improve diagnostic efficiency, we present here a magnetic separation method for bacteria that is based on mutated lysozyme (LysE35A) to capture S. aureus from whole blood. LysE35A-coated beads were able to bind different MSSA and MRSA isolates in the blood and also other six Gram-positive and two Gram-negative species in whole blood. This system was capable to bind bacteria at low concentrations (10CFU/ml) in spiked blood. Samples captured with the mutated lysozyme showed more responsive amplification of the 16S gene than whole blood at concentrations of 10(3)-10(5)CFU. These data demonstrate detection of S. aureus directly in blood samples, without in vitro cultivation. Our results show that capture with LysE35A-coated beads can be useful to develop a point of care diagnostic system for rapid and sensitive detection of pathogens in clinical settings.

The impact of thiamine supplementation on blood pressure, serum lipids and C-reactive protein in individuals with hyperglycemia: a randomised, double-blind cross-over trial

BACKGROUND

The adverse effects of hyperglycemia may be potentiated when it is accompanied with hypertension and dyslipidemia. This study assessed the effects of high dose thiamine on blood pressure, serum lipids and C-reactive protein (hs-CRP) in individuals with impaired glucose metabolism.

METHODS

This was a double-blind, randomised trial, where 12 hyperglycemic subjects (10 cases of impaired glucose tolerance and 2 new cases of type 2 diabetes mellitus) received both placebo and thiamine capsules (3 × 100 mg/day) for six weeks in a cross-over manner. Anthropometric measurements, systolic and diastolic blood pressure (SBP & DBP), serum cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol, hs-CRP and thiamine status were evaluated at the start, after three weeks and on the completion of each arm.

RESULTS

DBP was significantly decreased in participants consuming thiamine supplements for six weeks (67.9 ± 5.8 mm Hg) relative to baseline (71.4 ± 7.4 mm Hg, p=0.005) and week 3 (70.9. ± 5.8 mm Hg, p=0.02). This was accompanied with a tendency toward a lower SBP at week six relative to baseline (116.5 ± 11.0 vs. 120.7 ± 15.3 mm Hg, p=0.06). Also, mean arterial pressure (MAP) determined in the supplement arm after six weeks was significantly lower than baseline (84.1 ± 6.5 vs. 87.8 ± 9.0, p=0.005). These variables did not change in the placebo arm. No significant change was detected in the supplement or placebo arms when lipid profile and hs-CRP were assessed.

CONCLUSION/INTERPRETATION

High dose thiamine supplementation may have beneficial effects on the blood pressure of individuals with hyperglycemia at early stages, and may have a role in the prevention of further vascular complications.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12611000051943.

Vitamin D status and insulin sensitivity are novel predictors of resting metabolic rate: a cross-sectional analysis in Australian adults

PURPOSE

Resting metabolic rate (RMR) accounts for two-thirds of the total energy expenditure in sedentary individuals. After accounting for traditional factors, there still remains a considerable unexplained variance in RMR. There is a pandemic of obesity and metabolic syndrome (MetS) which coexists with a high prevalence of vitamin D insufficiency. The aim of this study was to evaluate the potential effects of vitamin D status, insulin sensitivity (IS) and the metabolic syndrome (MetS) on RMR in Australian adults.

METHODS

RMR, respiratory quotient (RQ), McAuley's insulin sensitivity index, fat mass (FM), fat-free mass (FFM) and vitamin D status were assessed in Australian adults. The presence of MetS was evaluated by current standard criteria. Predictors of RMR were examined through multiple linear regression based on stepwise and backward regression approaches with attention to multi-collinearity. All analyses were conducted on SPSS version 21.

RESULTS

One hundred and twenty-seven participants (45 men, 82 women), aged 53.4 ± 11.7 years and BMI 31.9 ± 5.2 kg/m(2), were included. Forty-one subjects were insufficient in vitamin D status (<50 nmol/L), and 75 participants had the MetS. A parsimonious regression model explained 85.8 % of RMR and was given by: RMR (kJ/d) = 1931 + 83.5 × FFM (kg) + 29.5 × FM (kg) + 5.65 × 25(OH)D (nmol/L) - 17.6 × age (years) - 57.51 × IS.

CONCLUSION

Vitamin D status and IS are novel independent predictors of RMR in adults. Future studies could validate a causal role for these factors in human energy metabolism.

A systematic review protocol examining the effect of vitamin D supplementation on endothelial function

INTRODUCTION

Vitamin D has potential benefits for extraskeletal health. These could include an anti-inflammatory effect as well as a reduction in endothelial dysfunction. We aim to provide quality evidence for the hypothesis that supplementation with vitamin D will improve endothelial function (EF), possibly through the abrogation of systemic inflammation.

METHODS AND ANALYSIS

We will conduct a systematic review of all randomised controlled trials on vitamin D supplementation and EF lasting 12 weeks or more. The search will cover the period 2000-2015 and include studies that describe direct measures of EF, markers of endothelial cell (EC) activation and if concurrently reported, indicators of systemic inflammation. Study selection will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and study quality will be assessed by the Jadad score in addition to an evaluation of allocation concealment and data analysis. If sufficient data are available, a meta-analysis will be conducted. The effect sizes will be generated using Hedges' g score, for both fixed and random effect models. I(2) statistics and Galbraith plots will be used to assess heterogeneity and identify their potential sources. Potential publication and small sample size bias will be assessed by visual inspections of funnel plots and also Egger's test. Meta-regression analysis (if feasible) will be conducted with restricted maximum likelihood (REML) estimation method, controlling for potential confounders (demographics, study methods, location, etc). A backward elimination process will be applied in the regression modelling procedure. Subgroup analysis, conditional on number of studies retrieved and their sample size, will be stratified on participant disease category, total dose administered, degree of 25(OH)D change and type of supplement used.

ETHICS AND DISSEMINATION

Formal ethical approval is not required as primary data will not be collected. The results will be disseminated through a peer-reviewed publication, conference presentation and the popular press.

TRIAL REGISTRATION NUMBER

International Prospective Register for Systematic Reviews (PROSPERO) number CRD42014013523.

Trypanosoma cruzi Intracellular Amastigotes Isolated by Nitrogen Decompression Are Capable of Endocytosis and Cargo Storage in Reservosomes

Epimastigote forms of Trypanosoma cruzi (the etiologic agent of Chagas disease) internalize and store extracellular macromolecules in lysosome-related organelles (LROs) called reservosomes, which are positive for the cysteine protease cruzipain. Despite the importance of endocytosis for cell proliferation, macromolecule internalization remains poorly understood in the most clinically relevant proliferative form, the intracellular amastigotes found in mammalian hosts. The main obstacle was the lack of a simple method to isolate viable intracellular amastigotes from host cells. In this work we describe the fast and efficient isolation of viable intracellular amastigotes by nitrogen decompression (cavitation), which allowed the analysis of amastigote endocytosis, with direct visualization of internalized cargo inside the cells. The method routinely yielded 5x10⁷ amastigotes—with typical shape and positive for the amastigote marker Ssp4—from 5x10⁶ infected Vero cells (48h post-infection). We could visualize the endocytosis of fluorescently-labeled transferrin and albumin by isolated intracellular amastigotes using immunofluorescence microscopy; however, only transferrin endocytosis was detected by flow cytometry (and was also analyzed by western blotting), suggesting that amastigotes internalized relatively low levels of albumin. Transferrin binding to the surface of amastigotes (at 4°C) and its uptake (at 37°C) were confirmed by binding dissociation assays using acetic acid. Importantly, both transferrin and albumin co-localized with cruzipain in amastigote LROs. Our data show that isolated T. cruzi intracellular amastigotes actively ingest macromolecules from the environment and store them in cruzipain-positive LROs functionally related to epimastigote reservosomes.

Biological activity of the essential oils from Cinnamodendron dinisii and Siparuna guianensis

This study had analyzed the antibacterial, antifungal and trypanocidal activity of the essential oils from Cinnamodendron dinisii Schwacke (Canellaceae) and Siparuna guianensis Aublet (Siparunaceae). The essential oils were obtained from fresh leaves by hydrodistillation, using a modified Clevenger apparatus. Chemical analysis by gas-liquid chromatography coupled to mass spectrometry (GC-MS) showed that these essential oils are rich in monoterpene and sesquiterpene hydrocarbons. Activity against the pathogenic bacteria Escherichia coli , Listeria monocytogenes , Pseudomonas aeruginosa , Salmonella choleraesuis and Staphylococcus aureus was evaluated with the agar cavity diffusion method, while activity on the filamentous fungi Aspergillus flavus , Aspergillus niger , Aspergillus carbonarius and Penicillium commune was evaluated by the disk diffusion technique. Trypanocidal activity was tested against Trypanosoma cruzi epimastigotes, using the Tetrazolium salt (MTT) colorimetric assay. Both essential oils exhibited low inhibitory effect towards bacteria, showing high MIC values (125-500 μg mL (-1) ), with Gram positive bacteria being more susceptible. Better inhibitory effect was obtained for the evaluated fungi, with lower MIC values (7.81-250 μg mL (-1) ), being A. flavus the most susceptible species. Both essential oils presented low trypanocidal activity, with IC 50 /24 h values of 209.30 μg mL (-1) for S. guianensis and 282.93 μg mL (-1) for C. dinisii . Thus, the high values observed for the MIC of evaluated bacteria and for IC 50 /24 h of T. cruzi , suggest that the essential oils have a low inhibitory activity against these microorganisms. In addition, the low MIC values observed for the tested fungi species indicate good inhibitory activity on these microorganisms's growth.

Actin expression in trypanosomatids (Euglenozoa: Kinetoplastea)

Heteroxenic and monoxenic trypanosomatids were screened for the presence of actin using a mouse polyclonal antibody produced against the entire sequence of the Trypanosoma cruzi actin gene, encoding a 41.9 kDa protein. Western blot analysis showed that this antibody reacted with a polypeptide of approximately 42 kDa in the whole-cell lysates of parasites targeting mammals (T. cruzi, Trypanosoma brucei and Leishmania major), insects (Angomonas deanei, Crithidia fasciculata, Herpetomonas samuelpessoai and Strigomonas culicis) and plants (Phytomonas serpens). A single polypeptide of approximately 42 kDa was detected in the whole-cell lysates of T. cruzi cultured epimastigotes, metacyclic trypomastigotes and amastigotes at similar protein expression levels. Confocal microscopy showed that actin was expressed throughout the cytoplasm of all the tested trypanosomatids. These data demonstrate that actin expression is widespread in trypanosomatids.

Genetic polymorphisms of phase I and phase II metabolic enzymes as modulators of lung cancer susceptibility

OBJECTIVES

Tobacco exposure remains the main etiologic factor for lung cancer (LC). Interactions between environment and individual genetic profile are particularly important for this disease. The aim of this study was to evaluate the contribution of CYP1A1*2A, CYP1A1*2C, CYP2D6*4, GSTP1, GSTM1, GSTT1 and NAT2 polymorphisms for the susceptibility to LC in a Portuguese population considering their demographic and clinical characteristics.

MATERIALS AND METHODS

A total of 200 LC and 247 controls subjects from the Centre of Portugal were studied. Clinical and demographic characteristics were collected from clinical files and by individual questionnaires. Polymorphisms of CYP1A1*2A, CYP1A1*2C, CYP2D6*4, GSTP1, GSTM1, GSTT1 and NAT2 were genotyped using PCR-RFLP, PCR multiplex, ARMS and real time.

RESULTS

Gender, family history of cancer, smoke cessation and alcohol consumption were independent risk factors (p < 0.05). Associations found between phases I and II genes and LC population reveal a sex dependent distribution. Logistic regression analysis demonstrates that enhanced activation by CYPs, associated by reduced or loss of function of phase II enzymes, can lead to a greater risk. GSTP1 and NAT2 polymorphisms studied have a significant contribution for the histological tumour types and the presence of metastases, at time of diagnosis, respectively, when males with smoking habits were considered.

CONCLUSION

Multiple interactions between environment and individual characteristics are clearly associated to this disease. Variants of the detoxification genes may act synergistically contributing to this disease and modifying the risk posed by smoking and sex. The GSTT1*0 and GSTP1 (Ile462Val) might contribute to the malignant phenotype through different mechanisms.

Profile of depressive symptoms in women in the perinatal and outside the perinatal period: similar or not?

PURPOSES

To analyze which Beck Depression Inventory-II (BDI-II) and Postpartum Depression Screening Scores (PDSS) total and dimensional scores, as well as symptomatic answers proportions significantly differ between women in the perinatal period (pregnant/postpartum) without major depression, with major depression and women outside the perinatal period.

METHODS

572 pregnant women in the third trimester completed Beck Depression Inventory-II and Postpartum Depression Screening Scale and were assessed with the Diagnostic Interview for Genetic Studies. 417 of these were also assessed (with the same instruments) at three months postpartum. Ninety non-pregnant women or that did not have a child in the last year (mean age=29.42±7.159 years) also filled in the questionnaires.

RESULTS

Non-depressed pregnant women showed lower scores than depressed pregnant women and higher scores than women outside the perinatal period in the BDI-II total score and in its Somatic-Anxiety dimension. Non-depressed postpartum women showed significantly higher scores than women outside the perinatal period only at Sleep/Eating Disturbances. Compared to women outside the perinatal period, pregnant women without depression presented higher scores only in the somatic items. Women with vs. without depression in the postpartum period did not significantly differ and both presented higher scores than women outside the perinatal period in the proportions of loss of energy and sleep changes.

LIMITATIONS

Women outside the perinatal period were not diagnosed for the presence of a depressive disorder, but their BDI-II mean score was similar to the figures reported worldwide regarding women in childbearing age.

CONCLUSION

In the perinatal period, most particularly at pregnancy, women experience significant somatic changes even if not clinically depressed. Cognitive-affective symptoms are more useful when assessing the presence of perinatal depression.

Vitamin D supplementation and body weight status: a systematic review and meta-analysis of randomized controlled trials

Vitamin D is anticipated to have many extra-skeletal health benefits. We questioned whether supplementation with the vitamin influenced body weight and composition. A systematic review and meta-analysis was conducted on high-quality, randomized controlled trials (RCTs) that had supplemented vitamin D without imposing any caloric restriction. Eighteen trials reporting either body weight, body mass index (BMI), fat mass (FM), percentage fat mass (%FM) or lean body mass (LBM) met our criteria. Twelve studies provided the required data for the meta-analysis. Vitamin D supplementation did not influence the standardized mean difference (SMD) for body weight, FM, %FM or LBM. A small but non-significant decrease in BMI (SMD = -0.097, 95% confidence interval: [-0.210, 0.016], P = 0.092) was observed. Meta-regression confirmed that neither the absolute vitamin D status achieved nor its change from baseline influenced the SMD of any obesity measure. However, increasing age of the subjects predicted a shift in the SMD for FM towards the placebo treatment, whereas a greater percentage of women in these studies favoured a decrease in FM following vitamin D. Vitamin D supplementation did not decrease measures of adiposity in the absence of caloric restriction. A potential confounding by age and gender was encountered.

EPR detection of paramagnetic chromium in liver of fish (Anguilla anguilla) treated with dichromate(VI) and associated oxidative stress responses-contribution to elucidation of toxicity mechanisms

The impact of chromium (Cr) on fish health has been the subject of numerous investigations, establishing a wide spectrum of toxicity, attributed particularly to the hexavalent form [Cr(VI)]. However, reports on the simultaneous assessment of Cr toxicity in fish and its toxico-kinetics, namely involving metal speciation, are scarce. Therefore, keeping in view the understanding of the mechanisms of Cr(VI) toxicity, this work intended to detect the formation of paramagnetic Cr species in liver of Anguilla anguilla following short-term dichromate(VI) intraperitoneal treatment (up to 180 min), assessing simultaneously the pro-oxidant properties. The formation of Cr(V) and Cr(III) was examined by electron paramagnetic resonance (EPR), as an innovative approach in the context of fish toxicology, and related with the levels of total Cr. Cr(V) was successfully detected and quantified by EPR spectrometry, showing a transient occurrence, mostly between 15 and 90 min post-injection, with a peak at 30 min. The limitations of EPR methodology towards the detection and quantification of Cr(III) were confirmed. Although Cr(VI) exposure induced the antioxidant system in the eel's liver, the oxidative deterioration of lipids was not prevented. Overall, the results suggested that Cr(V), as a short-lived species, did not appear to be directly and primarily responsible for the cellular damaging effects observed, since stress responses persisted up to the end of exposure regardless Cr(V) drastic decay. Though further research is needed, ROS mediated pathways (suggested by superoxide dismutase and catalase activity induction) and formation of Cr(III) complexes emerged as the most plausible mechanisms involved in Cr(VI) toxicity.

Identification and subcellular localization of TcHIP, a putative Golgi zDHHC palmitoyl transferase of Trypanosoma cruzi

Protein palmitoylation is a post-translational modification that contributes to determining protein localization and function. Palmitoylation has been described in trypanosomatid protozoa, but no zDHHC palmitoyl transferase has been identified in Trypanosoma cruzi, the etiological agent of Chagas disease in Latin America. In this study we identify and show the subcellular localization of TcHIP (Tc00.1047053508199.50), a putative T. cruzi zDHHC palmitoyl transferase. Analysis of the deduced protein sequence indicates that it contains ankyrin repeats (Ank and Ank2) and the zDHHC conserved domain, typical of zDHHC palmitoyl transferases. A TcHIP polyclonal antiserum obtained from mice immunized with the purified recombinant protein was used to study the presence and subcellular localization of the native enzyme. In western blots this antiserum recognized a protein of about 95 kDa, consistent with the predicted molecular mass of TcHIP (95.4 kDa), in whole extracts of T. cruzi epimastigotes, metacyclic trypomastigotes and intracellular amastigotes. Immunolocalization by confocal microscopy showed TcHIP labeling at the Golgi complex, co-localizing with the T. cruzi Golgi marker TcRab7-GFP. Transfectant T. cruzi epimastigotes containing a construct encoding TcHIP fused to proteins A and C (TcHIP/AC) were obtained. In western blotting experiments, the TcHIP polyclonal antiserum recognized both native and TcHIP/AC proteins in extracts of the transfectants. Confocal microscopy showed co-localization of native TcHIP with TcHIP/AC. These findings demonstrate the presence of a putative zDHHC palmitoyl transferase (TcHIP) containing ankyrin and zDHHC domains in different developmental forms of T. cruzi, and its association with the Golgi complex.

Trypanosoma cruzi response to sterol biosynthesis inhibitors: morphophysiological alterations leading to cell death

The protozoan parasite Trypanosoma cruzi displays similarities to fungi in terms of its sterol lipid biosynthesis, as ergosterol and other 24-alkylated sterols are its principal endogenous sterols. The sterol pathway is thus a potential drug target for the treatment of Chagas disease. We describe here a comparative study of the growth inhibition, ultrastructural and physiological changes leading to the death of T. cruzi cells following treatment with the sterol biosynthesis inhibitors (SBIs) ketoconazole and lovastatin. We first calculated the drug concentration inhibiting epimastigote growth by 50% (EC(50)/72 h) or killing all cells within 24 hours (EC(100)/24 h). Incubation with inhibitors at the EC(50)/72 h resulted in interesting morphological changes: intense proliferation of the inner mitochondrial membrane, which was corroborated by flow cytometry and confocal microscopy of the parasites stained with rhodamine 123, and strong swelling of the reservosomes, which was confirmed by acridine orange staining. These changes to the mitochondria and reservosomes may reflect the involvement of these organelles in ergosterol biosynthesis or the progressive autophagic process culminating in cell lysis after 6 to 7 days of treatment with SBIs at the EC(50)/72 h. By contrast, treatment with SBIs at the EC(100)/24 h resulted in rapid cell death with a necrotic phenotype: time-dependent cytosolic calcium overload, mitochondrial depolarization and reservosome membrane permeabilization (RMP), culminating in cell lysis after a few hours of drug exposure. We provide the first demonstration that RMP constitutes the "point of no return" in the cell death cascade, and propose a model for the necrotic cell death of T. cruzi. Thus, SBIs trigger cell death by different mechanisms, depending on the dose used, in T. cruzi. These findings shed new light on ergosterol biosynthesis and the mechanisms of programmed cell death in this ancient protozoan parasite.

Factors determining the risk of the metabolic syndrome: is there a central role for adiponectin?

BACKGROUND AND OBJECTIVES

The pathogenesis of the metabolic syndrome (MetS) is not well understood. This review is based on the hypothesis that both traditional and emerging risk factors act through adiponectin.

SUBJECTS AND METHODS

We conducted a search of the literature using prominent electronic databases and search terms that included in combination: adiponectin, diet, dietary patterns, exercise, metabolic rate, MetS and testosterone. Articles were restricted to studies conducted on adult humans, reported in English and within the time period 2000-2012.

RESULTS AND CONCLUSIONS

Both traditional and emerging risk factors associated with the MetS show some evidence of exerting their influence through adiponectin. High-quality randomized controlled trials that alter adiponectin levels are required to further corroborate this hypothesis.

Endocytosis in Trypanosoma cruzi (Euglenozoa: Kinetoplastea) epimastigotes: visualization of ingested transferrin-gold nanoparticle complexes by confocal laser microscopy

Here we describe the visualization by confocal microscopy of ingested gold (15 nm)-labeled transferrin in epimastigote forms of the protozoan Trypanosoma cruzi. Intracellular gold labeling was evident at two sites, which represent the bottom of the cytopharynx and the reservosomes. The gold tracer was best observed by confocal microscopy by using the 633 nm excitation wavelength. Intracellular gold clusters larger than 60 nm could be visualized by either gold reflection (light scattering) or photoluminescence modes. The gold reflection mode, the gold photoluminescence mode and the anti-transferrin immunofluorescence image of gold-labeled transferrin showed co-localization, thus demonstrating that the gold visualization modes did not represent artifacts or mislocalization of the biomarker. Visualization of protein-gold nanoparticle complexes by confocal microscopy thus emerges as a promising imaging tool to explore the endocytic pathway in trypanosomes and other cell types, as well as to perform immunolocalization studies using gold-labeled secondary antibodies.

Mechanistic roles for calcium and vitamin D in the regulation of body weight

Low intakes of calcium and inadequate vitamin D status often cluster with higher prevalence rates of obesity. Consequently, there has been much interest in the mechanisms by which calcium and vitamin D could regulate body weight and adiposity. This review has focused on randomized controlled trials (RCTs) that have manipulated these nutrients and studied pathways of energy balance. Overall, there is consistent evidence that calcium and vitamin D increase whole body fat oxidation after single and multiple meals, and that calcium promotes a modest energy loss through increased faecal fat excretion. The evidence is equivocal for a greater diet-induced thermogenesis, increased lipolysis, suppression of key lipogenic enzymes, decreased hunger ratings or reduced energy/macronutrient intake. Emerging evidence suggests a potential improvement in insulin sensitivity following vitamin D that would impinge on food intake and substrate oxidation. However, the very few RCTs on supplemental vitamin D and energy balance have not explored postprandial avenues of the hormone's actions. Future efforts in this area need to define the threshold intake of these nutrients that would maximize metabolic and gastrointestinal outcomes. Such studies would provide a platform for endorsing the non-skeletal role of calcium and vitamin D in human pathophysiology.

Rat placentation: an experimental model for investigating the hemochorial maternal-fetal interface

The rat possesses hemochorial placentation with deep intrauterine trophoblast cell invasion and trophoblast-directed uterine spiral artery remodeling; features shared with human placentation. Recognition of these similarities spurred the establishment of in vitro and in vivo research methods using the rat as an animal model to address mechanistic questions regarding development of the hemochorial placenta. The purpose of this review is to provide the requisite background to help move the rat to the forefront in placentation research.

Review: Genetic manipulation of the rodent placenta

The principal role of the placenta is the maintenance of pregnancy and promotion of fetal growth and viability. The use of transgenic rodents has greatly enhanced our understanding of placental development and function. However, embryonic lethality is often a confounding variable in determining whether a genetic modification adversely affected placental development. In these cases, it is beneficial to specifically manipulate the placental genome. The purpose of this review is to summarize available methodologies for specific genetic modification of the rodent placenta. By restricting genetic alterations to the trophoblast lineage, it is possible to gain a deeper understanding of placental development that perhaps will lead to gene-targeted therapies to rescue irregular placentation in transgenic animals or in women at high-risk for placenta-associated pregnancy complications.

IFPA Meeting 2010 Workshops Report II: Placental pathology; trophoblast invasion; fetal sex; parasites and the placenta; decidua and embryonic or fetal loss; trophoblast differentiation and syncytialisation

Workshops are an important part of the IFPA annual meeting. At IFPA Meeting 2010 diverse topics were discussed in twelve themed workshops, six of which are summarized in this report. 1. The placental pathology workshop focused on clinical correlates of placenta accreta/percreta. 2. Mechanisms of regulation of trophoblast invasion and spiral artery remodeling were discussed in the trophoblast invasion workshop. 3. The fetal sex and intrauterine stress workshop explored recent work on placental sex differences and discussed them in the context of whether boys live dangerously in the womb.4. The workshop on parasites addressed inflammatory responses as a sign of interaction between placental tissue and parasites. 5. The decidua and embryonic/fetal loss workshop focused on key regulatory mediators in the decidua, embryo and fetus and how alterations in expression may contribute to different diseases and adverse conditions of pregnancy. 6. The trophoblast differentiation and syncytialisation workshop addressed the regulation of villous cytotrophoblast differentiation and how variations may lead to placental dysfunction and pregnancy complications.

Resistance training for obese, type 2 diabetic adults: a review of the evidence

In both developed and developing countries, increased prevalence of obesity has been strongly associated with increased incidence of type 2 diabetes mellitus (T2DM) in the adult population. Previous research has emphasized the importance of physical activity in the prevention and management of obesity and T2DM, and generic exercise guidelines originally developed for the wider population have been adapted for these specific populations. However, the guidelines traditionally focus on aerobic training without due consideration to other exercise modalities. Recent reviews on resistance training in the T2DM population have not compared this modality with others including aerobic training, or considered the implications of resistance training for individuals suffering from both obesity and T2DM. In short, the optimal mix of exercise modalities in the prescription of exercise has not been identified for it benefits to the metabolic, body composition and muscular health markers common in obesity and T2DM. Similarly, the underlying physical, social and psychological barriers to adopting and maintaining exercise, with the potential to undermine the efficacy of exercise interventions, have not been addressed in earlier reviews. Because it is well established that aerobic exercise has profound effects on obesity and T2DM risk, the purpose of this review was to address the importance of resistance training to obese adults with T2DM.

Knockout of the gene encoding the kinetoplast-associated protein 3 (KAP3) in Trypanosoma cruzi: effect on kinetoplast organization, cell proliferation and differentiation

Kinetoplast DNA (kDNA) of trypanosomatid protozoa consists of an unusual arrangement of two types of circular molecules catenated into a single network: (1) a few maxicircles that encode various mitochondrial enzyme subunits and rRNA in a cryptic pattern and (2) thousands of minicircles that encode guide RNAs (gRNAs). kDNA is associated with proteins, known as kinetoplast-associated proteins (KAPs), which condense the kDNA network. However, little is known about the KAPs of Trypanosoma cruzi, a parasite that displays different kDNA condensation patterns during its complex morphogenetic development. We cloned the T. cruzi gene encoding TcKAP3 (kinetoplast-associated protein 3). TcKAP3 is a single-copy gene that is transcribed into a 1.8-kb mRNA molecule and expressed in all stages of the parasite. Mouse antiserum raised against recombinant TcKPA3 recognized a 21.8kDa protein, which was found, by indirect immunofluorescence and immunoelectron microscopy, to be associated with the T. cruzi kinetoplast. Several features of TcKAP3, such as its small size, basic nature and similarity with KAP3 from the insect trypanosomatid Crithidia fasciculata, are consistent with a role in DNA charge neutralization and condensation. This suggests that this protein is involved in organizing the kDNA network. Gene deletion was used to investigate TcKAP3 function. Here we investigated the T. cruzi KAP3 null mutant, analyzing its fitness during proliferation, differentiation and infectivity.

Noggin maintains pluripotency of human embryonic stem cells grown on Matrigel

OBJECTIVE

Spontaneous differentiation of human embryonic stem cell (hESC) cultures is a major concern in stem cell research. Physical removal of differentiated areas in a stem cell colony is the current approach used to keep the cultures in a pluripotent state for a prolonged period of time. All hESCs available for research require unidentified soluble factors secreted from feeder layers to maintain the undifferentiated state and pluripotency. Under experimental conditions, stem cells are grown on various matrices, the most commonly used being Matrigel.

MATERIALS AND METHODS

We propose an alternative method to prevent spontaneous differentiation of hESCs grown on Matrigel that uses low amounts of recombinant noggin. We make use of the porosity of Matrigel to serve as a matrix that traps noggin and gradually releases it into the culture to antagonize bone morphogenetic proteins (BMP). BMPs are known to initiate differentiation of hESCs and are either present in the conditioned medium or are secreted by hESCs themselves.

RESULTS

hESCs grown on Matrigel supplemented with noggin in conditioned medium from feeder layers (irradiated mouse embryonic fibroblasts) retained both normal karyotype and markers of hESC pluripotency for 14 days. In addition, these cultures were found to have increased cell proliferation of stem cells as compared to hESCs grown on Matrigel alone.

CONCLUSION

Noggin can be utilized for short term prevention of spontaneous differentiation of stem cells grown on Matrigel.

Intrauterine fate of invasive trophoblast cells

Invasion of trophoblast cells into the uterine spiral arteries and the uterine wall is characteristic of hemochorial placentation. In the rat, trophoblast cells penetrate through the uterine decidua and well into the metrial gland. In this report, we examined the fate of these invasive trophoblast cells following parturition. Invasive trophoblast endocrine cells were retained in the postpartum mesometrial uterus in the rat. The demise of invasive trophoblast cells was followed by the appearance of differentiated smooth muscle cells surrounding blood vessels previously lined by invasive trophoblast cells and an infiltration of macrophages. Regulation of intrauterine trophoblast cell fate was investigated following premature removal of the fetus or removal of the fetus and chorioallantoic placenta. The presence of the fetus affected the distribution of invasive trophoblast cells within the uterus but did not negatively impact their survival. Premature removal of all chorioallantoic placentas and associated fetuses from a uterus resulted in extensive removal of intrauterine trophoblast cells. In summary, the postpartum demise of intrauterine invasive trophoblast cells is a dynamic developmental event regulated in part by the removal of trophic signals emanating from the chorioallantoic placenta.

Is there a role for monounsaturated fat in the dietary management of obesity?

Animal and human studies indicate that high saturated fat (SFA) diets can be obesogenic. Monounsaturated fat (MUFA) has acute (meal related) effects that influence energy metabolism. These include increased postprandial fat oxidation and greater diet induced thermogenesis, factors that attenuate weight gain. Chronic (diet related) studies for 12 weeks or more, demonstrate that people following high MUFA diets do not gain excessive weight even when eating ad libitum. In fact, we have observed greater body weight and fat loss in men following an ad libitum MUFA diet, when compared to a SFA diet. High MUFA diets designed for weight loss should also incorporate a high vegetable intake according to traditional Mediterranean patterns. Such diets will promote the utilisation of fat and also have a low energy density. In our experience these diets are well accepted, and offer the prospect of greater long-term adherence to dietary advice.

Isolation of cardiac mast cells in experimental Trypanosoma cruzi infection

Mast cells (MC) secrete diverse pre-stored chemical mediators that are pivotal in inflammatory and fibrotic etiologies, such as Trypanosoma cruzi-induced myocardiopathy. However, due to reduced number of cardiac MC, in situ and in vitro identification, and difficult tissue isolation, these cells are rarely addressed. In this work we optimized the identification of cardiac and peritoneal MC and developed an enzymatic method for MC isolation using control and T. cruzi-infected mice. MC were identified by: toluidine blue (TB); alcian blue (AB)/safranin (S); AB or a mixed solution composed by AB/S/TB. Previous evaluations of cardiac MC in T. cruzi infection were based on TB staining and our results using AB/S/TB solution showed an increase in, at least, five times the detection of MC. This mixed solution may improve the identification of MC populations also from skin, mucosa and tissues that are infected by other pathogens or under the influence of chronic inflammation, leading to more precise results. Furthermore, the appropriate combination of samples (frozen/unfixed/thick slices) and staining protocols can assure the best evaluation of MC. We have also isolated cardiac MC using collagenase and developed a highly efficient 60%/70% Percoll-graded protocol that enriched in, at least, 95% the population of cardiac MC.

Anti-proliferative effect of the essential oil ofCymbopogon citratus(DC) Stapf (lemongrass) on intracellular amastigotes, bloodstream trypomastigotes and culture epimastigotes ofTrypanosoma cruzi(Protozoa: Kinetoplastida)

This study analyses the anti-proliferative effect of lemongrass essential oil and its main constituent (citral) on all 3 evolutive forms ofTrypanosoma cruzi. Steam distillation was used to obtain lemongrass essential oil, with chemical composition determined by gas chromatography (GC) and GC coupled to mass spectrometry (GC-MS). The IC50/24 h (concentration that reduced the parasite population by 50%) of the oil and of citral uponT. cruziwas determined by cell counting in a Neubauer chamber, while morphological alterations were visualized by scanning and transmission electron microscopy. Treatment with the essential oil resulted in epimastigote growth inhibition with IC50=126·5 μg/ml, while the IC50for trypomastigote lysis was 15·5 μg/ml. The IC50/48 h for the Association Index (% macrophage infection×number of amastigotes per cell) was 5·1 μg/ml, with a strong inhibition of intracellular amastigote proliferation. Ultrastructural analysis demonstrated cytoplasmic and nuclear extraction, while the plasma membrane remained morphologically preserved. Our data show that lemongrass essential oil is effective againstT. cruzitrypomastigotes and amastigotes, and that its main component, citral, is responsible for the trypanocidal activity. These results indicate that essential oils can be promising anti-parasitic agents, opening perspectives to the discovery of more effective drugs of vegetal origin for treatment of parasitic diseases. However, additional cytotoxicity experiments on different cell lines and tests in aT. cruzi-mouse model are needed to support these data.

Mitochondrial disruption and DNA fragmentation in Trypanosoma cruzi induced by naphthoimidazoles synthesized from beta-lapachone

Three naphthoimidazoles presenting aromatic groups attached to the imidazole ring were the most active against trypomastigotes of Trypanosoma cruzi between 45 derivatives from beta-lapachone. N1 is active against the three forms of the parasite. In this work, we investigated N2 and N3 and analyzed the effect of the three derivatives on metacyclogenesis, endocytosis, and cell cycle. In epimastigotes, N2 and N3 blocked the cell cycle, inhibited succinate cytochrome c reductase, metacyclogenesis, and induced damage to mitochondrion, Golgi, and reservosomes. In treated trypomastigotes, there were alterations in the mitochondrion, nucleus and kinetoplast, and DNA fragmentation. Preincubation with cysteine protease inhibitors reversed the effect of N1, N2, and N3. Such reversion and ultrastructural alterations suggest the involvement of autophagy in parasite death. Ultrastructural, flow cytometry, and biochemical studies suggest that naphthoimidazoles interferes with the energetic metabolism and induces DNA fragmentation.

Second meal effects of dietary calcium and vitamin D

OBJECTIVE

To determine the second meal effects of calcium and vitamin D on postprandial glucose, insulin, non-esterified fatty acids (NEFA) and glycerol.

METHODS

Eight volunteers aged (mean+/-s.e.m.) 55.5+/-1.2 years and body mass index 29.0+/-1.6 kg/m(2), completed a randomized within-subject design that compared a low calcium-low vitamin D breakfast and an isocaloric high calcium-high vitamin D breakfast (HCB). Four hours following each breakfast, a very low calcium standard lunch was ingested. Serial blood collections were made on the hour over a duration of 8 h. Postprandial responses were calculated as the percentage change (Delta) from the fasting value for breakfast meals, and the 4th hour breakfast value for each lunch, respectively. Non-parametric tests of significance were employed.

RESULTS

The change in glucose, insulin, serum ionized calcium (iCa(2+)) and intact parathyroid hormone was not different between the two breakfasts, or the two lunches. However, HCB resulted in a lesser suppression of NEFA that significantly carried over to lunch (P=0.036, Wilcoxon test). A similar pattern of change in glycerol did not attain overall statistical significance. DeltaNEFA and Deltaglycerol were related at lunch (Spearman's r=0.52, P=0.04). Relative to breakfast, both lunches resulted in significantly higher glucose and insulin responses (P=0.011, Wilcoxon test).

CONCLUSIONS

The data are suggestive of second meal effects of calcium and vitamin D. Our observations of higher glucose and insulin after lunch may include the involvement of second meal factors as well.