Parameters Influencing Baseline HIV-1 Genotypic Tropism Testing Related to Clinical Outcome in Patients on Maraviroc

ObjectivesWe analysed the impact of different parameters on genotypic tropism testing related to clinical outcome prediction in 108 patients on maraviroc (MVC) treatment.Methods87 RNA and 60 DNA samples were used. The viral tropism was predicted using the geno2pheno_[coreceptor] and T-CUP tools with FPR cut-offs ranging from 1%-20%. Additionally, 27 RNA and 28 DNA samples were analysed in triplicate, 43 samples with the ESTA assay and 45 with next-generation sequencing. The influence of the genotypic susceptibility score (GSS) and 16 MVC-resistance mutations on clinical outcome was also studied.ResultsConcordance between single-amplification testing compared to ESTA and to NGS was in the order of 80%. Concordance with NGS was higher at lower FPR cut-offs. Detection of baseline R5 viruses in RNA and DNA samples by all methods significantly correlated with treatment success, even with FPR cut-offs of 3.75%-7.5%. Triple amplification did not improve the prediction value but reduced the number of patients eligible for MVC. No influence of the GSS or MVC-resistance mutations but adherence to treatment, on the clinical outcome was detected.ConclusionsProviral DNA is valid to select candidates for MVC treatment. FPR cut-offs of 5%-7.5% and single amplification from RNA or DNA would assure a safe administration of MVC without excluding many patients who could benefit from this drug. In addition, the new prediction system T-CUP produced reliable results.     

Body size and the division of niche space: food and predation differentially shape the distribution of Serengeti grazers

1. Theory predicts that small grazers are regulated by the digestive quality of grass, while large grazers extract sufficient nutrients from low-quality forage and are regulated by its abundance instead. In addition, predation potentially affects populations of small grazers more than large grazers, because predators have difficulty capturing and handling large prey. 2. We analyse the spatial distribution of five grazer species of different body size in relation to gradients of food availability and predation risk. Specifically, we investigate how the quality of grass, the abundance of grass biomass and the associated risks of predation affect the habitat use of small, intermediate and large savanna grazers at a landscape level. 3. Resource selection functions of five mammalian grazer species surveyed over a 21-year period in Serengeti are calculated using logistic regressions. Variables included in the analyses are grass nitrogen, rainfall, topographic wetness index, woody cover, drainage lines, landscape curvature, water and human habitation. Structural equation modelling (SEM) is used to aggregate predictor variables into 'composites' representing food quality, food abundance and predation risk. Subsequently, SEM is used to investigate species' habitat use, defined as their recurrence in 5 × 5 km cells across repeated censuses. 4. The distribution of small grazers is constrained by predation and food quality, whereas the distribution of large grazers is relatively unconstrained. The distribution of the largest grazer (African buffalo) is primarily associated with forage abundance but not predation risk, while the distributions of the smallest grazers (Thomson's gazelle and Grant's gazelle) are associated with high grass quality and negatively with the risk of predation. The distributions of intermediate sized grazers (Coke's hartebeest and topi) suggest they optimize access to grass biomass of sufficient quality in relatively predator-safe areas. 5. The results illustrate how top-down (vegetation-mediated predation risk) and bottom-up factors (biomass and nutrient content of vegetation) predictably contribute to the division of niche space for herbivores that vary in body size. Furthermore, diverse grazing assemblages are composed of herbivores of many body sizes (rather than similar body sizes), because these herbivores best exploit the resources of different habitat types.     

Synthesis and cytotoxic activity of non-naturally substituted 4-oxycoumarin derivatives

Coumarins are a large family of natural and synthetic compounds exerting different pharmacological effects, including cytotoxic, anti-inflammatory or antimicrobial. In the present communication we report the synthesis of a series of 12 diversely substituted 4-oxycoumarin derivatives including methoxy substituted 4-hydroxycoumarins, methyl, methoxy or unsubstituted 3-aryl-4-hydroxycoumarins and 4-benzyloxycoumarins and their anti-proliferative effects on breast adenocarcinoma cells (MCF-7), human promyelocytic leukemia cells (HL-60), human histiocytic lymphoma cells (U937) and mouse neuroblastoma cells (Neuro2a). The most potent bioactive molecule was the 4-hydroxy-5,7-dimethoxycoumarin (compound 1) which showed similar potency (IC(50) 0.2-2μM) in all cancer cell lines tested. This non-natural product reveals a simple bioactive scaffold which may be exploited in further studies.     

ApoB100/LDLR-/- hypercholesterolaemic mice as a model for mild cognitive impairment and neuronal damage

Recent clinical findings support the notion that the progressive deterioration of cholesterol homeostasis is a central player in Alzheimer's disease (AD). Epidemiological studies suggest that high midlife plasma total cholesterol levels are associated with an increased risk of AD. This paper reports the plasma cholesterol concentrations, cognitive performance, locomotor activity and neuropathological signs in a murine model (transgenic mice expressing apoB100 but knockout for the LDL receptor [LDLR]) of human familial hypercholesterolaemia (FH). From birth, these animals have markedly elevated LDL-cholesterol and apolipoprotein B100 (apoB100) levels. These transgenic mice were confirmed to have higher plasma cholesterol concentrations than wild-type mice, an effect potentiated by aging. Further, 3-month-old transgenic mice showed cholesterol (total and fractions) concentrations considerably higher than those of 18-month-old wild-type mice. The hypercholesterolaemia of the transgenic mice was associated with a clear locomotor deficit (as determined by rotarod, grip strength and open field testing) and impairment of the episodic-like memory (determined by the integrated memory test). This decline in locomotor activity and cognitive status was associated with neuritic dystrophy and/or the disorganization of the neuronal microtubule network, plus an increase in astrogliosis and lipid peroxidation in the brain regions associated with AD, such as the motor and lateral entorhinal cortex, the amygdaloid basal nucleus, and the hippocampus. Aortic atherosclerotic lesions were positively correlated with age, although potentiated by the transgenic genotype, while cerebral β-amyloidosis was positively correlated with genetic background rather than with age. These findings confirm hypercholesterolaemia as a key biomarker for monitoring mild cognitive impairment, and shows these transgenic mice can be used as a model for cognitive and psycho-motor decline.     

Enhanced visualization of microbial biofilms by staining and environmental scanning electron microscopy

Bacterial biofilms, i.e. surface-associated cells covered in hydrated extracellular polymeric substances (EPS), are often studied with high-resolution electron microscopy (EM). However, conventional desiccation and high vacuum EM protocols collapse EPS matrices which, in turn, deform biofilm appearances. Alternatively, wet-mode environmental scanning electron microscopy (ESEM) is performed under a moderate vacuum and without biofilm drying. If completely untreated, however, EPS is not electron dense and thus is not resolved well in ESEM. Therefore, this study was towards adapting several conventional SEM staining protocols for improved resolution of biofilms and EPS using ESEM. Three different biofilm types were used: 1) Pseudomonas aeruginosa unsaturated biofilms cultured on membranes, 2) P. aeruginosa cultured in moist sand, and 3) mixed community biofilms cultured on substrates in an estuary. Working with the first specimen type, a staining protocol using ruthenium red, glutaraldehyde, osmium tetroxide and lysine was optimized for best topographic resolution. A quantitative image analysis tool that maps relief, newly adopted here for studying biofilms, was used to compare micrographs. When the optimized staining and ESEM protocols were applied to moist sand cultures and aquatic biofilms, the smoothening effect that bacterial biofilms have on rough sand, and the roughening that aquatic biofilms impart on initially smooth coupons, were each quantifiable. This study thus provides transferable staining and ESEM imaging protocols suitable for a wide range of biofilms, plus a novel tool for quantifying biofilm image data.     

The consumption of two new probiotic strains, Lactobacillus gasseri CECT 5714 and Lactobacillus coryniformis CECT 5711, boosts the immune system of healthy humans.

Orally ingested probiotic bacteria are able to modulate the immune system. However, differences exist in the immunomodulatory effects of different probiotic strains. Moreover, different regulatory effects, which depend on the health status of the consumer, have been identified. This work describes a randomized, double-blind, placebo-controlled human clinical trial to investigate the immune effects on healthy people of a fermented product containing two new probiotic strains, Lactobacillus gasseri CECT 5714 and Lactobacillus coryniformis CECT 5711, which was compared with another fermented product, a standard yogurt. Consumption of either the new product or yogurt increased the proportion of phagocytic cells, including monocytes and neutrophils, as well as their phagocytic activity. However, combination of the product containing the strains L. gasseri CECT 5714 and L. coryniformis CECT 5711 also induced an increase in the proportion of natural killer (NK) cells and in IgA concentrations. The effects were higher after two weeks of treatment than after 4 weeks, which suggests regulation of the immune system. In addition, the new product enhanced immunity in the participants to a greater extent than did the control standard yogurt.     

Intestinal and immunological effects of daily oral administration of Lactobacillus salivarius CECT5713 to healthy adults

There is an increasing interest in the intestinal and immunological effects of probiotics. The aim of the present study is to evaluate the tolerance and beneficial effects in healthy adults of the strain, Lactobacillus salivarius CECT5713 isolated from breast milk. A phase II, randomized, double-blinded, placebo-controlled human clinical trial was carried out in 40 healthy adults. The Probiotic group received a daily dose of 2 × 10⁸ CFU of L. salivarius CECT5713 in capsules during 4 weeks while volunteers of the control received only a placebo. Gastrointestinal and immunological parameters were analyzed. Results showed that L. salivarius CECT5713 was well tolerated and no adverse effects were detected. Consumption of the probiotic strain increased fecal lactobacilli counts (7.9 ± 0.1 vs. 7.05 ± 0.2 CFU/g feces, P = 0.001). Also, an improvement in the frequency of defecation (P = 0.04) was observed. Probiotic treatment induced significantly the percentage of NK cells and monocytes, as well as the plasmatic levels of immunoglobulins M, A and G, and the regulatory cytokine IL-10 (72.3 ± 11.7 in probiotic group vs. 27.3 ± 6.4 pg/mL in control group, P < 0.01). Thus, it can be concluded that daily administration of L. salivarius CECT5713 to healthy adults is safe and improve gut microbiota and different parameters related to immune response.