The role of afforestation species as a driver of Hg accumulation in organic horizons of forest soils from a Mediterranean mountain area in SW Europe.

Forest areas are a primary sink of atmospheric mercury (Hg) within terrestrial ecosystems, whereas forest vegetation plays a key role in atmospheric Hg transfer to soil horizons. This study assessed variations in total Hg contents (HgT) and accumulation (HgRes) in the soil organic horizons of a forest area in NE Portugal, where post-wildfire afforestation led to the substitution of the native deciduous species (Quercus pyrenaica) by fast-growing coniferous species (Pseudotsuga menziesii and Pinus nigra). The study also evaluated, for each species, the links between Hg contents and other biophilic elements of soil organic matter (C, N, S) present in organic subhorizons (OL, OF, OH). Mean HgT in the organic horizons of the different tree species follow the sequence: P. nigra (88 µg kg-1) < Q.pyrenaica (101 µg kg-1)

A facile approach for tuning optical and surface properties of novel biobased Alginate/POTE handleable films via solvent vapor exposure.

Novel biobased films consisting of alginate blends with poly (octanoic acid 2-thiophen-3-yl-ethyl ester) (POTE), a conducting polymer, were prepared by solution casting, and their optical, morphological, thermal, and surface properties were studied. Using UV-visible spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM), the effects of tetrahydrofuran solvent vapors on the optical properties and surface morphology of biobased films with different POTE contents were studied. Results indicate that morphological rearrangements of POTE take place during the process of solvent exposure. Specifically, the solvent vapor induced the formation of POTE small crystalline domains, which allows envisioning the potential of tuning UV-visible absorbance and wettability behavior of biobased films. Finally, theoretical electronic calculations (specifically frontier molecular orbitals analysis) provided consistent evidence on POTE's preferential orientation and selectivity toward the THF-vapor medium.

Litterfall Hg deposition to an oak forest soil from southwestern Europe.

Litterfall constitutes one of the main vectors for mercury (Hg) transfer to forested ecosystems, so we studied the deposition of Hg through senescent vegetation (oak leaves, twigs and miscellaneous) in a deciduous forest plot of Southwest Europe dominated by Quercus robur in 2015 and 2016. Total Hg concentrations increased in the following order: bole wood (1.4 µg kg-1) < bark (8.3 µg kg-1) < twigs (12.2 µg kg-1) < miscellaneous (36.0 µg kg-1) < oak leaves (39.3 µg kg-1) < mineral soil (42.4 µg kg-1) < Oi horizons (48.7 µg kg-1) < Oe + Oa horizons (71.6 µg kg-1). Mercury accumulation rates in oak leaves during the growing season were 0.15-0.18 µg kg-1 day-1. Mercury deposition fluxes were 26 and 21 µg m-2 yr-1 for 2015 and 2016, respectively, with oak leaves being the fraction that contributed the most. Mercury determination in litterfall sorted biomass fractions lead to a more accurate estimation of the total annual Hg deposition fluxes through litterfall. Higher Hg content was obtained for organic horizons (average of 60.2 µg kg-1) than for mineral soil (mean of 42.4 µg kg-1), but the soil Hg pool was higher in the latter. The results confirmed the necessity of taking into account the Hg pool in the deeper mineral soil layers as they accumulate substantial quantities of Hg associated to organic C and Al compounds, preventing its mobilization to other compartments of the terrestrial ecosystems.

Induction Immunosuppressive Therapy Use in Deceased Donor Kidney Transplantation: 11-Year Experience in Veracruz, Mexico.

BACKGROUND: Induction therapy reduces the frequency of acute rejection and delayed graft function in renal transplantation. Basiliximab and Thymoglobulin are most commonly used agents for induction. METHODS: A retrospective study of two transplant centers in Veracruz, Mexico compared induction therapy in deceased donor renal transplantation from 2003 to 2014. Efficacy and safety outcomes evaluated were primary graft nonfunction, delayed graft function, acute rejection episodes and hospitalizations during first year, and patient and graft survival. P < .05 was considered statistically significant. RESULTS: Seventy deceased kidney donors (40 male) were studied. Mean donor age was 32.9 ± 14.3 years, mean donor BMI 25.6 ± 4.3 kg/m(2), and mean donor creatinine 1.13 ± 0.58 mg/dL. Main cause of death was trauma (62.9%). In total, 125 kidney transplantations were performed, with female predominance (53.6%) and mean age 33.8 ± 11.8 years. Of these, 66.4% used basiliximab and 33.6% Thymoglobulin. Thymoglobulin patients were significantly older, with lower weight and BMI, and were on dialysis longer than basiliximab patients. DGF was present in 19.3% of basiliximab patients vs 16.7% in Thymoglobulin patients, acute rejection occurred in 16.9% of basiliximab patients vs 19% Thymoglobulin patients. A total of 33.7% basiliximab patients were hospitalized during the first year vs 47.6% Thymoglobulin-induced patients (P > .05). Mean graft survival was 84.2 ± 5.3 months (73.8-94.7) basiliximab vs 32.4 ± 28.7 months (28.7-36.1) Thymoglobulin, Kaplan-Meier survival did not show statistically significant differences between groups (P = .276; CI 95%). CONCLUSION: Similar transplant outcomes were obtained using basiliximab or Thymoglobulin induction in our population.

Effects of a high protein diet on cognition and brain metabolism in cirrhotic rats.

Hepatic encephalopathy (HE) is a neurological complication observed in patients with liver disease. Patients who suffer from HE present neuropsychiatric, neuromuscular and behavioral symptoms. Animal models proposed to study HE resulting from cirrhosis mimic the clinical characteristics of cirrhosis and portal hypertension, and require the administration of hepatotoxins such as thioacetamide (TAA). The aim of this study was to assess the effects of a high protein diet on motor function, anxiety and memory processes in a model of cirrhosis induced by TAA administration. In addition, we used cytochrome c-oxidase (COx) histochemistry to assess the metabolic activity of the limbic system regions. Male rats were distributed into groups: control, animals with cirrhosis, Control rats receiving a high protein diet, and animals with cirrhosis receiving a high protein diet. Results showed preserved motor function and normal anxiety levels in all the groups. The animals with cirrhosis showed an impairment in active avoidance behavior and spatial memory, regardless of the diet they received. However, the animals with cirrhosis and a high protein diet showed longer escape latencies on the spatial memory task. The model of cirrhosis presented an under-activation of the dentate gyrus and CA3 hippocampal subfields and the medial part of the medial mammillary nucleus. The results suggest that a high protein intake worsens spatial memory deficits shown by the TAA-induced model of cirrhosis. However, high protein ingestion has no influence on the COx hypoactivity associated with the model.

Rejection is a strong graft survival predictor in live donor pediatric renal transplantation using cyclosporine, mycophenolate mofetil, and steroids: 5-year outcomes in a single Mexican center.

Long-term graft function and survival are of particular importance in children assuming that they have a longer transplantation life span than most adults. Because acute rejection episodes (ARE) continue to have a serious impact on graft loss, we analyzed the effects of ARE on 5-year survival and function in our population. Fifty-seven living donor kidney transplant recipients (34 males) younger than 18 years of age (13.5 ± 2.6 years; range, 5-17) were follow up for at feast 12 months using cyclosporine, mycophenolate mofetil, and steroid therapy with or without induction treatment between February 2003 and December 2010. ARE incidence during the first 12 months following transplantation was 14%. One-, 3- and 5-year serum creatinine values were 1.24 ± 0.39, 2.16 ± 2.39, and 1.76 ± 0.9 mg/dL, respectively. Mean calculated creatinine clearances (Schwartz) at 1, 3, and 5 years were 82.5 ± 24.8, 64.7 ± 24.1, and 67 ± 27.5 mL/min*1.73 m(2), respectively. Patient/graft survival rates were 96/85%, 90/72%, and 88/65% at 1, 3, and 5 years, respectively. Patients who experienced an ARE within 12 months following transplantation displayed a reduced 5-year graft survival rate (37.5%) versus those who did not (78%; P = .005). Patients who did not have an ARE during 60 months had a higher graft survival rate (76%) than those who had ARE (33%; P = .001). Patient without basiliximab induction showed a lower 5-year graft survival rate (61% vs 100%; P = not significant [NS]). ARE is an important risk factor for graft loss in the pediatric kidney transplant population.

Spatial learning-related changes in metabolic activity of limbic structures at different posttask delays.

The aim of this study was to assess the functional contribution of brain limbic system regions at different moments after the acquisition of a short-term spatial memory task performed in the Morris water maze. Adult male Wistar rats were submitted to a matching-to-sample procedure with a hidden platform. The trials were made up of two daily identical visits to the platform, sample (swim-1) and retention (swim-2). To study oxidative metabolic activity, we applied cytochrome oxidase (COx) histochemistry. Densitometric measurements were taken at 1.5, 6, 24, and 48 hr posttask. An untrained group was added to explore the COx changes not specific to the learning process. The brain regions studied showed a different pattern of metabolic activity at different time points after the spatial memory task. Specifically, a significant increase of COx was found in the septal dentate gyrus, anteromedial thalamus, medial mammillary nucleus, and entorhinal cortex at early moments after learning. The entorhinal cortex maintained an increase of COx at later stages of the posttask period. In addition, an increase of COx activity was found in the supramammillary nucleus and the retrosplenial, perirhinal, and parietal cortices a long time after learning. These findings suggest that diencephalic and cortical regions are involved in this spatial learning and contribute at different moments to process this information.

Similarities and differences between the brain networks underlying allocentric and egocentric spatial learning in rat revealed by cytochrome oxidase histochemistry.

The involvement of different brain regions in place- and response-learning was examined using a water cross-maze. Rats were trained to find the goal from the initial arm by turning left at the choice point (egocentric strategy) or by using environmental cues (allocentric strategy). Although different strategies were required, the same maze and learning conditions were used. Using cytochrome oxidase histochemistry as a marker of cellular activity, the function of the 13 diverse cortical and subcortical regions was assessed in rats performing these two tasks. Our results show that allocentric learning depends on the recruitment of a large functional network, which includes the hippocampal CA3, dentate gyrus, medial mammillary nucleus and supramammillary nucleus. Along with the striatum, these last three structures are also related to egocentric spatial learning. The present study provides evidence for the contribution of these regions to spatial navigation and supports a possible functional interaction between the two memory systems, as their structural convergence may facilitate functional cooperation in the behaviours guided by more than one strategy. In summary, it can be argued that spatial learning is based on dynamic functional systems in which the interaction of brain regions is modulated by task requirements.

Portosystemic hepatic encephalopathy model shows reversal learning impairment and dysfunction of neural activity in the prefrontal cortex and regions involved in motivated behavior.

Hepatic encephalopathy (HE) is a neurological complication that affects attention and memory. Experimental animal models have been used to study HE, the most frequent being the portacaval shunt (PCS). In order to investigate learning impairment and brain functional alterations in this model, we assessed reversal learning and neural metabolic activity in a PCS rat model. PCS and sham-operated rats were tested for reversal learning in the Morris water maze. Brains were then processed for cytochrome oxidase (CO) histochemistry. The PCS group had reversal learning impairment and a reduction in CO activity in the prefrontal cortex, ventral tegmental area and accumbens shell nucleus. These results suggest that this model of portosystemic HE shows learning impairments that could be linked to dysfunction in neural activity in the prefrontal cortex and regions involved in motivated behavior.

Interhippocampal transfer in passive avoidance task modifies metabolic activity in limbic structures.

The hippocampus is probably the most studied brain structure regarding memory. Each brain hemisphere contains one hippocampus, and subjects with unilateral hippocampal lesions can perform adequately in several behavioral tasks. This property allows studying how both hippocampi interact. In this work, we show that the information acquired in a passive avoidance task with one hippocampus can be retrieved and used by the brain when the hippocampal side involved in the acquisition is blocked with TTX. The pre-exposition to the context is decisive. By combining behavioral tasks and cytochrome oxidase histochemistry we demonstrated that several brain structures, including the hippocampus, amygdala and other related regions, change their activity under the above-mentioned treatments.

Prehepatic portal hypertension worsens the enterohepatic redox balance in thioacetamide-cirrhotic rats.

BACKGROUND: Oxidative stress has been reported as a key pathogenic factor in many human liver diseases and in experimental models of cirrhosis related to hepatotoxin administration. The aim of this study was to verify the hypothesis that prehepatic portal hypertension aggravates the enterohepatic redox imbalance in thioacetamide-cirrhotic rats. MATERIALS AND METHODS: Wistar male rats were used: Control (n=9); rats with prehepatic portal hypertension by triple partial portal vein ligation (TPVL; n=9); thioacetamide-cirrhotic rats (TAA; n=9) and TPVL-rats associated to TAA administration (TPVL+TAA; n=9). Three months after the operation, portal pressure (PP), mesenteric venous vasculopathy (MVV) and portosystemic collateral circulation were studied. Liver and ileal levels of malondialdehyde (MDA), as a lipid peroxidation marker, and catalase (CAT), glutathione peroxidase (GSH-Px), glutathione transferase (GSH-t) and cytosolic and mitochondrial superoxide dismutases (cSOD and mSOD), as antioxidative enzymatic mechanisms, were measured. RESULTS: Liver and ileal MDA increased in all the experimental groups, although the higher increase occurred in the ileum of rats with portal hypertension. CAT levels decreased in the liver and the ileum in the three experimental groups. The decrease in liver and ileal GSH-Px and GSH-t was greater in rats with portal hypertension, alone or associated with TAA. mSOD activation was demonstrated in the liver when portal hypertension was added to TAA. On the contrary, this compensatory response was not activated in the ileum, where mSOD was significantly decreased. CONCLUSION: Prehepatic portal hypertension by triple partial portal vein ligation impaired the enterohepatic antioxidative activity and aggravated the intestinal oxidative stress in thioacetamide-cirrhotic rats.

Unilateral hippocampal blockade reveals that one hippocampus is sufficient for learning a passive avoidance task.

Understanding hippocampal participation in memory processes is one of the goals in neuroscience research. By blocking the hippocampus unilaterally in Wistar rats, we assessed the contribution of this brain structure to memory in a passive avoidance task. Subjects were distributed into four groups. Group 1 received tetrodotoxin (TTX) in the right hippocampus during acquisition and retrieval phases. Group 2 had the same procedure as group 1, except that the contralateral hippocampus was blocked during retrieval. Subjects from group 3 acquired the task with saline (both hippocampi intact) and retrieved with the right hippocampus inactivated. Finally, group 4 received TTX unilaterally 2 min after acquisition to determine the hippocampal role in consolidation. Results showed that group 2 was impaired, compared with the other groups, during retrieval. These findings reveal that the hippocampal contribution to this task differs from that in other tasks considered to be hippocampus dependent.

[Bladder amyloidosis]. / Amiloidosis vesical.

We present a case of Vesical Amyloidosis (V.A.) in a woman with Rheumatoid Arthritis. Clinical data, other locations and Histochemical findings are consistent with Secondary Amyloidosis. After T.U.R., she was treated with Dimethylsulfoxide (DMSO) and Colchicine. Her severe hematuria disappeared.