Evaluation of natural background levels of high mountain karst aquifers in complex hydrogeological settings. A Gaussian mixture model approach in the Port del Comte (SE, Pyrenees) case study

The hydrogeological processes driving the hydrochemical composition of groundwater in the alpine pristine aquifer system of the Port del Comte Massif (PCM) are characterized through the multivariate statistical techniques Principal Component Analysis (PCA) and Gaussian Mixture Models (GMM) in the framework of Compositional Data (CoDa) analysis. Also, the groundwater Natural Background Levels (NBLs) for NO₃ and SO₄ and Cl are evaluated, which are specially important for indicating the occurrence of groundwater contamination derived from the anthropic activities conducted in the PCM. The different hydrogeochemical facies found in the aquifer system of the PCM comprises low mineralized Ca-HCO₃ water for the main Eocene karst aquifer, and Ca-SO₄ and highly mineralized NaCl water types in the minor aquifers discharging from the PCM. The NBL values of SO₄, Cl and NO₃ obtained for the main karst aquifer are 14.33, 4.06 and 6.55 mg/L, respectively. These values are 35, 3 and 1.2 times lower than the respective official NBLs values that were determined by the water administration to be compared with in the case of conducting a pollution assessment characterization in the main karst aquifer. Official overestimation of NBLs can put important groundwater resources in the PCM at risk.

Contribution of isotopic research techniques to characterize high-mountain-Mediterranean karst aquifers: The Port del Comte (Eastern Pyrenees) aquifer

Water resources in high mountain karst aquifers are usually characterized by high rainfall, recharge and discharge that lead to the sustainability of the downstream ecosystems. Nevertheless, these hydrological systems are vulnerable to the global change impact. The mean transit time (MTT) is a key parameter to describe the behavior of these hydrologic systems and also to assess their vulnerability. This work is focused on estimating MTT by using environmental tracers in the framework of high-mountain karst systems with a very thick unsaturated zone (USZ). To this end, it is adapted to alpine zones a methodology that combines a semi-distributed rainfall-runoff model to estimate recharge time series, and a lumped-parameter model to obtain ΜΤΤ. The methodology has been applied to the Port del Comte Massif (PCM) hydrological system (Southeastern Pyrenees, NE Spain), a karst aquifer system with an overlying 1000 m thick USZ. Six catchment areas corresponding to most important springs of the system are considered. The obtained results show that hydrologically the behavior of the system can be described by an exponential flow model (EM), with MTT ranging between 1.9 and 2.9 years. These ΜΤΤ values are shorter than those obtained by considering a constant recharge rate along time, which is the easiest and most applied aquifer recharge hypothesis when estimating ΜΤΤ through lumped-parameter models.

Regional diversity in the murine cortical vascular network is revealed by synchrotron X-ray tomography and is amplified with age

Cortical bone is permeated by a system of pores, occupied by the blood supply and osteocytes. With ageing, bone mass reduction and disruption of the microstructure are associated with reduced vascular supply. Insight into the regulation of the blood supply to the bone could enhance the understanding of bone strength determinants and fracture healing. Using synchrotron radiation-based computed tomography, the distribution of vascular canals and osteocyte lacunae was assessed in murine cortical bone and the influence of age on these parameters was investigated. The tibiofibular junction from 15-week- and 10-month-old female C57BL/6J mice were imaged post-mortem. Vascular canals and three-dimensional spatial relationships between osteocyte lacunae and bone surfaces were computed for both age groups. At 15 weeks, the posterior region of the tibiofibular junction had a higher vascular canal volume density than the anterior, lateral and medial regions. Intracortical vascular networks in anterior and posterior regions were also different, with connectedness in the posterior higher than the anterior at 15 weeks. By 10 months, cortices were thinner, with cortical area fraction and vascular density reduced, but only in the posterior cortex. This provided the first evidence of age-related effects on murine bone porosity due to the location of the intracortical vasculature. Targeting the vasculature to modulate bone porosity could provide an effective way to treat degenerative bone diseases, such as osteoporosis.

Sost Deficiency does not Alter Bone's Lacunar or Vascular Porosity in Mice

SCLEROSTIN (Sost) is expressed predominantly in osteocytes acting as a negative regulator of bone formation. In humans, mutations in the SOST gene lead to skeletal overgrowth and increased bone mineral density, suggesting that SCLEROSTIN is a key regulator of bone mass. The function of SCLEROSTIN as an inhibitor of bone formation is further supported by Sost knockout (KO) mice which display a high bone mass with elevated bone formation. Previous studies have indicated that Sost exerts its effect on bone formation through Wnt-mediated regulation of osteoblast differentiation, proliferation, and activity. Recent in vitro studies have also suggested that SCLEROSTIN regulates angiogenesis and osteoblast-to-osteocyte transition. Despite this wealth of knowledge of the mechanisms responsible for SCLEROSTIN action, no previous studies have examined whether SCLEROSTIN regulates osteocyte and vascular configuration in cortices of mouse tibia. Herein, we image tibiae from Sost KO mice and their wild-type (WT) counterparts with high-resolution CT to examine whether lack of SCLEROSTIN influences the morphometric properties of lacunae and vascular canal porosity relating to osteocytes and vessels within cortical bone. Male Sost KO and WT mice (n = 6/group) were sacrificed at 12 weeks of age. Fixed tibiae were analyzed using microCT to examine cortical bone mass and architecture. Then, samples were imaged by using benchtop and synchrotron nano-computed tomography at the tibiofibular junction. Our data, consistent with previous studies show that, Sost deficiency leads to significant enhancement of bone mass by cortical thickening and bigger cross-sectional area and we find that this occurs without modifications of tibial ellipticity, a measure of bone shape. In addition, our data show that there are no significant differences in any lacunar or vascular morphometric or geometric parameters between Sost KO mouse tibia and WT counterparts. We, therefore, conclude that the significant increases in bone mass induced by Sost deficiency are not accompanied by any significant modification in the density, organization, or shape of osteocyte lacunae or vascular content within the cortical bone. These data may imply that SCLEROSTIN does not modify the frequency of osteocytogenic recruitment of osteoblasts to initiate terminal osteocytic differentiation in mice.

Clinical value of PET/CT's SUV max at baseline, early follow-up, and end of treatment reevaluation as a prognostic factor in small cell lung cancer patients with extended disease

e18558

Background: Patients with Small Cell Lung Cancer (SCLC) have been staged by the two-stage system. This system defines limited disease (LD) when is confined to ipsilateral hemithorax that can be encompassed within tolerable radiation field; extended disease (ED) is defined as the disease extending outside the hemithorax. The IASLC recommended that TNM staging should be used in SCLC including clinical trials. However these systems have shown poor correlation between clinical findings and the pathological results. Objectives: Evaluate prognostic factors as age, ECOG and PET CT’s SUV max at base line, early follow up and end of treatment reevaluation; and their correlation with Overall survival (OS) and Progression free survival (PFS). Methods: Prospectively were recruited patients with histologically confirmed SCLC and ED and were evaluated with basal PET CT, early follow up (PET CT after 2 cycles of Platinum based chemotherapy) and end of treatment assessment with a PET CT after 6 cycles. Comprehensive database including clinical data were collected as age, ECOG, site of metastases, type of treatment and outcome. 23 patients were recruited from January 2010 to June 2012 and the follow up made until January 15th 2013. The Cox correlation test was used. Results: Median age 66,5 years (range 52-80) the OS was 7,9 months (CI 95% 6.7-9.1) and the PFS was 5,3 months (CI 95% 4,5-6,2). The baseline ECOG was an independent prognostic factor for OS (p= <0,0001) and PSF (p= 0,008). Age was not prognostic in our data. SUV max at baseline was an independent prognostic factor for OS (p= 0,001) and PFS (p= 0,009). For early follow up were evaluated 14 patients and for end of treatment reevaluation were assessed 9 patients. Differences between SUV max at baseline and early follow up or with end of treatment reevaluation were not predictive for PFS or OS. Conclusions: In our study the ECOG and basal PET CT SUV max are independent prognosis factors with consistent correlation with OS and PFS. The early follow up and end of treatment reevaluation with PET CT did not predict outcome in our patients. Further studies should be considered to test the value of follow up with PET CT.

Local conjunctival immunotherapy: the effect of dermatophagoides pteronyssinus local conjunctival immunotherapy on conjunctival provocation test in patients with allergic conjunctivitis

BACKGROUND

We evaluated the effect of local conjunctival immunotherapy (LCIT) with standardized dermatophagoides pteronyssinus (Dp) extracts on antigen-specific conjunctival provocation test (CPT) in patients with allergic conjunctivitis in a double blind, placebo-controlled study. We use the CPT because in our experience is the more objective parameter to evaluate the sensitivity to allergens in this patients.

METHODS

The patients were selected on the basis of symptoms, positive prick test, positive CPT and elevated serum and tears total and specific IgE. The CPT was assessed with increased dilution of Dp extracts instilled into the lower fornix. Conjunctival hyperemia, tearing, itching, burning and swelling of eyelids were scored according a 4-point rating scale. Patients were randomly assigned to 2 groups of 12. The first group was treated with Dp extracts and the second group with placebo during 6 months. A drop of diluted antigen was instilled in both eyes daily, in 2-fold increased concentrations, the first 10 AU/ml. The maintenance dose was 1,000 AU/ml or the maximal dose which did not provoke symptoms. The symptoms were controlled with oral and/or local antihistamines. We evaluated the CPT before and after the treatment. The patients did not receive antihistamines during the 15 previous days to carrying-out the CPT.

RESULTS

Ten of the twelve patients of the active group complete the treatment. One of the patients dropped out of the study because experienced local reaction with a dose of 1,000 AU/ml and refused to continue with the treatment. Other patient was disqualified for failure to comply with the protocol. One patient, which experienced itching and tearing with a dose of 1,000 AU/ml, tolerate 100 AU/ml. We continue with this dose until the end of treatment. The remaining patients tolerate 1,000 AU/ml as maintenance dose. A significant difference was observed in the score of CPT between LCIT treated patients and placebo group after 6 month of LCIT.

CONCLUSIONS

We propose LCIT as a useful alternative to traditional subcutaneous immunotherapy in patients with allergic conjunctivitis.

Oxygen consumption in the foraging honeybee depends on the reward rate at the food source

Oxygen consumption of the honeybee Apis mellifera ligustica was measured as a function of the flow rate supply of sucrose solution at an automatic feeder located inside a respirometric chamber. Trained bees freely entered the respirometric chamber and collected the sucrose solution supplied. The mean value of the O2 consumption rate per visit increased with the sucrose flow rate, and for a given flow rate, with increasing locomotor activity. However, when no locomotor activity was displayed, O2 consumption also increased with increasing nectar flow rate. Crop load attained at the end of the visit showed a positive relationship with the nectar flow rate; however, for a given flow rate, O2 consumption showed either no correlation or a negative one with the final crop load attained. It is concluded that the energy expenditure of the foraging bee is controlled by a motivational drive whose intensity depends on the reward rate at the food source.

Baker's yeast, an attractant for baiting traps for Chagas' disease vectors

We tested the attraction of volatile compounds, produced by the aerobic growth of Saccharomyces cerevisiae on saccharose for Triatoma infestans. For these tests, we exploited the behavioural characteristic of these haematophagous insects of dropping when searching for food. In olfactometer assays, yeast cultures activated and attracted bugs as effectively as a mouse. The attraction of the cultures was significantly reduced when the carbon dioxide released was partially eliminated using potassium hydroxide. Yeast cultures were also tested as lures in a novel trap device. A baited device for trapping Chagas' disease vectors using the behavioural peculiarities of T. infestans and this simple attractant is described.

Metabolic rate during foraging in the honeybee

The metabolic rate of free-flying honeybees, Apis mellifera ligustica, was determined by means of a novel respirometric device that allowed measurement of CO2 produced by bees foraging under controlled reward at an artificial food source. Metabolic rate increased with reward (sugar flow rate) at the food source. In addition, there was no clear-cut dependence of metabolic rate on load carried during the visit, neither as crop load nor as supplementary weights attached to the thorax. The hypothesis that metabolic rate, as well as foraging and recruiting activities, depend on the motivational state of the foraging bee determined by the reward at the food source is discussed.