Hybrid Methacrylated Gelatin and Hyaluronic Acid Hydrogel Scaffolds. Preparation and Systematic Characterization for Prospective Tissue Engineering Applications.

Hyaluronic acid (HA) and gelatin (Gel) are major components of the extracellular matrix of different tissues, and thus are largely appealing for the construction of hybrid hydrogels to combine the favorable characteristics of each biopolymer, such as the gel adhesiveness of Gel and the better mechanical strength of HA, respectively. However, despite previous studies conducted so far, the relationship between composition and scaffold structure and physico-chemical properties has not been completely and systematically established. In this work, pure and hybrid hydrogels of methacroyl-modified HA (HAMA) and Gel (GelMA) were prepared by UV photopolymerization and an extensive characterization was done to elucidate such correlations. Methacrylation degrees of ca. 40% and 11% for GelMA and HAMA, respectively, were obtained, which allows to improve the hydrogels' mechanical properties. Hybrid GelMA/HAMA hydrogels were stiffer, with elastic modulus up to ca. 30 kPa, and porous (up to 91%) compared with pure GelMA ones at similar GelMA concentrations thanks to the interaction between HAMA and GelMA chains in the polymeric matrix. The progressive presence of HAMA gave rise to scaffolds with more disorganized, stiffer, and less porous structures owing to the net increase of mass in the hydrogel compositions. HAMA also made hybrid hydrogels more swellable and resistant to collagenase biodegradation. Hence, the suitable choice of polymeric composition allows to regulate the hydrogels´ physical properties to look for the most optimal characteristics required for the intended tissue engineering application.

Combination of light-driven co-delivery of chemodrugs and plasmonic-induced heat for cancer therapeutics using hybrid protein nanocapsules.

BACKGROUND: Improving the water solubility of hydrophobic drugs, increasing their accumulation in tumor tissue and allowing their simultaneous action by different pathways are essential issues for a successful chemotherapeutic activity in cancer treatment. Considering potential clinical application in the future, it will be promising to achieve such purposes by developing new biocompatible hybrid nanocarriers with multimodal therapeutic activity. RESULTS: We designed and characterised a hybrid nanocarrier based on human serum albumin/chitosan nanoparticles (HSA/chitosan NPs) able to encapsulate free docetaxel (DTX) and doxorubicin-modified gold nanorods (DOXO-GNRs) to simultaneously exploit the complementary chemotherapeutic activities of both antineoplasic compounds together with the plasmonic optical properties of the embedded GNRs for plasmonic-based photothermal therapy (PPTT). DOXO was assembled onto GNR surfaces following a layer-by-layer (LbL) coating strategy, which allowed to partially control its release quasi-independently release regarding DTX under the use of near infrared (NIR)-light laser stimulation of GNRs. In vitro cytotoxicity experiments using triple negative breast MDA-MB-231 cancer cells showed that the developed dual drug encapsulation approach produces a strong synergistic toxic effect to tumoral cells compared to the administration of the combined free drugs; additionally, PPTT enhances the cytostatic efficacy allowing cell toxicities close to 90% after a single low irradiation dose and keeping apoptosis as the main cell death mechanism. CONCLUSIONS: This work demonstrates that by means of a rational design, a single hybrid nanoconstruct can simultaneously supply complementary therapeutic strategies to treat tumors and, in particular, metastatic breast cancers with good results making use of its stimuli-responsiveness as well as its inherent physico-chemical properties.

(Bio)electrochemical ammonia recovery: progress and perspectives.

In recent years, (bio)electrochemical systems (B)ES have emerged as an energy efficient alternative for the recovery of TAN (total ammonia nitrogen, including ammonia and ammonium) from wastewater. In these systems, TAN is removed or concentrated from the wastewater under the influence of an electrical current and transported to the cathode. Subsequently, it can be removed or recovered through stripping, chemisorption, or forward osmosis. A crucial parameter that determines the energy required to recover TAN is the load ratio: the ratio between TAN loading and applied current. For electrochemical TAN recovery, an energy input is required, while in bioelectrochemical recovery, electric energy can be recovered together with TAN. Bioelectrochemical recovery relies on the microbial oxidation of COD for the production of electrons, which drives TAN transport. Here, the state-of-the-art of (bio)electrochemical TAN recovery is described, the performance of (B)ES for TAN recovery is analyzed, the potential of different wastewaters for BES-based TAN recovery is evaluated, the microorganisms found on bioanodes that treat wastewater high in TAN are reported, and the toxic effect of the typical conditions in such systems (e.g., high pH, TAN, and salt concentrations) are described. For future application, toxicity effects for electrochemically active bacteria need better understanding, and the technologies need to be demonstrated on larger scale.

Endemic species may have complex histories: within-refugium phylogeography of an endangered Iberian vole.

Glacial refugia protected and promoted biodiversity during the Pleistocene, not only at a broader scale, but also for many endemics that contracted and expanded their ranges within refugial areas. Understanding the evolutionary history of refugial endemics is especially important in the case of endangered species to recognize the origins of their genetic structure and thus produce better informed conservation practices. The Iberian Peninsula is an important European glacial refugium, rich in endemics of conservation concern, including small mammals, such as the Cabrera vole (Microtus cabrerae). This near-threatened rodent is characterized by an unusual suite of genetic, life history and ecological traits, being restricted to isolated geographic nuclei in fast-disappearing Mediterranean subhumid herbaceous habitats. To reconstruct the evolutionary history of the Cabrera vole, we studied sequence variation at mitochondrial, autosomal and sex-linked loci, using invasive and noninvasive samples. Despite low overall mitochondrial and nuclear nucleotide diversities, we observed two main well-supported mitochondrial lineages, west and east. Phylogeographic modelling in the context of the Cabrera vole's detailed fossil record supports a demographic scenario of isolation of two populations during the Last Glacial Maximum from a single focus in the southern part of the Iberian Peninsula. In addition, our data suggest subsequent divergence within the east, and secondary contact and introgression of the expanding western population, during the late Holocene. This work emphasizes that refugial endemics may have a phylogeographic history as rich as that of more widespread species, and conservation of such endemics includes the preservation of that genetic legacy.

Influence of nanosecond repetitively pulsed discharges on the stability of a swirled propane/air burner representative of an aeronautical combustor.

This paper reports on an experimental study of the influence of a nanosecond repetitively pulsed spark discharge on the stability domain of a propane/air flame. This flame is produced in a lean premixed swirled combustor representative of an aeronautical combustion chamber. The lean extinction limits of the flame produced without and with plasma are determined and compared. It appears that only a low mean discharge power is necessary to increase the flame stability domain. Lastly, the effects of several parameters (pulse repetition frequency, global flowrate, electrode location) are studied.

Uranium mining in Portugal: a review of the environmental legacies of the largest mines and environmental and human health impacts.

The history of uranium mining in Portugal during almost one century has followed international demand peaks of both radium and uranium, which in turn were driven by medical, military, and civil applications. Nowadays, following price drop in the 1980s, mining activities decreased and ceased in 2001. The current challenge is to deal with environmental legacies left by old uranium mines, mainly located in Viseu and Guarda districts. In 2001, based on several radiological surveys carried out, the Portuguese government assumed the remediation costs of abandoned mine areas for environmental safety and public health protection. Detailed environmental and public health risk assessments were performed under the scope of studies both requested by the government and by funded research projects. It was found that the existing risks, due to radiological and chemical exposures to metals and radionuclide's, were particularly high at the old milling facilities and mines where in situ and heap leaching of low-grade ore occurred. The different studies, involving both humans and non-human species from different trophic levels, demonstrated the existence of effects at different levels of biological organization (molecular, cellular, tissues, individuals, and populations) and on ecosystem services. To mitigate the risks, the environmental rehabilitation works at the Urgeiriça mine complex are almost complete, while at Cunha Baixa mine, they are presently in progress. These works and environmental improvements achieved and expected are described herein.

Cytocompatibility and P-glycoprotein inhibition of block copolymers: structure-activity relationship.

Amphiphilic polymeric micelles greatly improve the solubilization and sustained release of hydrophobic drugs and provide a protective environment for the cargo molecules in aqueous media, which favors lower drug administration doses, reduces adverse side effects, and increases blood circulation times and passive targeting to specific cells. These capabilities depend, among other variables, on the structure and composition of the polymer chains. Composition and, in particular, block length have been shown to play an important role in the modification of cellular responses such as drug internalization processes or transduction pathways when polymeric unimer/micelles are in close contact with cells. Here we present a detailed study about the role copolymer structure and composition play on cell viability and cellular response of several cell lines. To do that, more than 30 structurally related copolymers with diblock and triblock architectures containing different hydrophobic blocks and poly(ethylene oxide) as the common hydrophilic unit have been analyzed regarding cytocompatibility and potential as "active" cell response modifiers by testing their influence on the P-gp pump efflux mechanism responsible of multidrug resistance in cancerous cells. An empirical threshold for cell viability could be established at a copolymer EO/POeffective value above ca. 1.5 for copolymers with triblock structure, whereas no empirical rule could be observed for diblocks. Moreover, some of the tested copolymers (e.g., BO12EO227BO12 and EO57PO46EO57 that notably increased and C16EO455C16 that decreased the P-gp ATPase activity) were observed to act as efficient inhibitors of the P-gp efflux pump promoting an enhanced doxorubicin (DOXO) accumulation inside multidrug resistant (MDR) NCI-ADR-RES cells.

Diastasis of rectus abdominis in the immediate puerperium: correlation between imaging diagnosis and clinical examination.

AIM: Diastasis of rectus abdominis is a condition defined as a separation between this muscle and the linea alba, which leads to weakness in the abdominal muscles. Later, such weakness will influence the biomechanical posture causing back pain in women. In the present study, our aim was to assess the accuracy of clinical examination in measuring diastasis of rectus abdominis in the postpartum period. METHOD: Puerperal women (n=106) were selected for this study, including caesarean delivery (62 %) and vaginal delivery (38 %). Diastasis of rectus abdominis was measured in the postpartum period using clinical examination and ultrasonography, at four levels of the anterior sheath of the rectus abdominis, in the region above the umbilical scar. RESULTS: At each level of measurement, the results were statistically analyzed using the Student's t and Pearson tests (confidence interval 95 %), Bland-Altman plot, and Kappa test. The Student t test showed no significant difference between clinical examination and ultrasonography. The Pearson test showed correlation with positive coefficients; moderate correlation (r > 0.5) in the first levels (3, 6, and 9 cm) and a strong correlation (r > 0.75) in the last level (12 cm). In the Kappa test, 65 % of diagnoses given in the clinical examination were confirmed by ultrasonography. CONCLUSIONS: These results show a good agreement between both forms of examination, allowing clinical examination to be used in the diagnosis of rectus muscle diastasis, when ultrasonography is not available.

Comparative in vitro and in planta analyses of extracellular enzymes secreted by the pathogenic fungus Sclerotinia sclerotiorum.

Dry bean (Phaseolus vulgaris L.) is an important economic crop in Brazil but its yield can be significantly reduced by white mold, a disease caused by Sclerotinia sclerotiorum (Lib.) de Bary, a necrotrophic, highly destructive, and non-host-specific fungus. This fungus secretes numerous cell wall-degrading enzymes such as polygalacturonases, exo-ß-1,3-glucanases, xylanases, and cellulases that have been detected during the early stages of infection. In this study, the activities of these enzymes were detected in all carbon sources tested (citrus pectin, cell wall extract from P. vulgaris, carboxymethyl cellulose, and glucose), but the highest levels were found when using citrus pectin and cell wall extract from P. vulgaris. Regardless of the carbon source, pH decreased throughout the culture time. During pathogenesis in dry bean stems, increased enzyme activities were also observed. Reverse transcriptase-polymerase chain reaction experiments showed that the induction of polygalacturonases (sspg1, sspg3, sspg5, sspg6, and sspg7), exo-ß-1,3-glucanases, and endo-ß-1-4-glucanase in S. sclerotiorum occurred during the early stages of colonization.

Human leucocytes response to viable, extended freeze-drying or heat-killed Mycobacterium bovis bacillus Calmette-Guérin.

We investigated the effects of viable, extended freeze-drying (EFD) or heat-killed (HK) Mycobacterium bovis bacillus Calmette-Guérin (BCG) in respiratory burst activity, gene expression of CYBB and NCF1 encoding components of the human phagocyte nicotinamide adenine dinucleotide (NADPH) oxidase, TLR2 expression, and in IL-10 and TNF-α cytokine production by human peripheral blood mononuclear cells (PBMCs). Viable BCG significantly inhibited TLR2 and CYBB gene expression, as well as superoxide release by human PBMC. All BCG stimuli augmented IL-10 release, but only HK BCG or viable BCG increased TNF-α release by PBMCs. Our studies show that viable BCG can impair the NADPH oxidase system activation and the TLR2 route in human PBMCs. As well, different BCG preparations can distinctly influence cytokine production by human PBMCs.

Ovarian steroids modulate the systemic inflammatory response OF COWS challenged with lipopolysaccharide (LPS) intrauterine infusion.

Postpartum uterine infections of dairy cows promote a local and systemic inflammation and interfere with reproductive efficiency. The aim of this study was to evaluate the effect of steroid hormones including progesterone (P4) and estradiol (E2) on the systemic inflammatory response of cows after being challenged with an intrauterine infusion of lipopolysaccharide (LPS). For this, a hemogram and serum dosage of haptoglobin (Hp) in eight primiparous Gir cows ovariectomized were performed on day (day 0) and after 24 h (day +1). Four cows (n = 4) were challenged (day 0) with 20 mL of 0.9% NaCl + 12.5 µg/kg LPS, and four cows (n = 4) were challenged (day 0) with 20 mL of 0.9% NaCl. For this, the study was divided in four experimental groups as: (1) Control group: without any hormonal treatment before day 0; (2) Group 24 h - E2: 1 mg of estradiol benzoate 24 h before (day -1); (3) Group 24 h - P4: 2.0 g of P4 device 24 h before (day -1); (4) Group 14 d - P4: 2.0 g of P4 device 14 days before (day -14). In the systemic response to LPS, there was an increase in Hp (control group; 24 h - P4 group; 14 d - P4 group), and on day +1 the Hp of 14 d - P4 group was higher when compared to the other groups. On day 0, the 14 d - P4 group had an increase in circulating leukocytes and lymphocytes cells than the control group (P < 0.01). On day +1 after LPS-challenge the 14 d - P4 group showed a decrease in circulating lymphocytes, eosinophils, and monocytes (P < 0.05). A neutrophilia with left shift in the two treatments with P4 (day +1), in addition to a thrombocytopenia and lower platelets compared to the 24 h - E2 group (P < 0.05) (day 0) were recorded. It was concluded that ovariectomized cows challenged with LPS, previously submitted to steroid hormones induce a systemic inflammatory response. Also, the systemic response is more intense after previous prolonged exposure to P4 and less intense after exposure to E2. This study provided important information relating the effect of ovarian steroids on the systemic inflammatory response of cows challenged with intrauterine LPS.

Labaditin, a cyclic peptide with rich biotechnological potential: preliminary toxicological studies and structural changes in water and lipid membrane environment.

Cyclic peptides isolated from the plants of the Euphorbiaceae family have been largely studied due to their rigid conformation, which is considered significant for biologic activity. The peptide Labaditin (L(0)) and its open chain analogs (L(1)) were synthesized by the solid-phase peptide synthesis technique (Fmoc/tBu), and purified to elucidate its interaction with membrane models. A shift in λ(max) emission and Stern-Volmer constants values indicate that both tryptophans migrate to a more apolar environment, with L(1) decreasing less than L(0). A circular dichroism (CD) study revealed that L(0) was kept unstructured in aqueous media as much as in the presence of dipalmitoilphosphatidylcholine liposomes. The thermodynamic studies by differential calorimetry (DSC) show a ΔH increase (50 and 18 kcal/mol, for L(0) and L(1), respectively) with peptide concentrations, which is indicative of lipids associating with peptides, resulting in the inability of the lipids to participate in the main transition. Therefore, all CD, DSC, and fluorescence data suggest a greater L(0) membrane insertion. A probable mechanism for Labaditin interaction is based initially on the hydrophobic interaction of the peptide with the lipid membrane, conformational change, peptide adsorption on the lipid surface, and internalization process. Peptide's antibacterial effect was also evaluated and revealed that only L(0) showed reduction in viability in Gram-positive bacteria while no effects to the Gram-negative.

Third times a charm: reviewing the advertisement call of Gabohyla pauloalvini (Anura: Hylidae: Scinaxinae), an endemic species from Brazil Atlantic Forest.

The Neotropical tribe Sphaenorhynchini is composed of 15 recognized species commonly named as lime treefrogs. Gabohyla pauloalvini occurs in Atlantic Forest lowlands through the states of Bahia and Esprito Santo, Brazil. Based on field observation, literature review, and evaluation of audio files, we conclude that previous bioacoustic descriptions were erroneously assigned to G. pauloalvini. Here, we describe for the first time the advertisement call of G. pauloalvini from two disjunct populations. In addition, we provide new distribution records and an updated map for this species. The advertisement call of G. pauloalvini is composed of 15 closely spaced notes, with duration of 0.0161.976 s, inter-note intervals of 0.3401.25 s, and an average dominant frequency (= fundamental frequency) of 4966.0 Hz. Harmonics are visible in the spectrogram. Three new populations of G. pauloalvini have been recorded and extended the distribution by 60 km south. Nevertheless, G. pauloalvini is still known only from few localities. We highlight the importance of depositing audio recordings and specimens in scientific collections to promote systematics and natural history studies.

The prion fragment PrP106-127 adopts a secondary structure typical of aggregated fibrils in langmuir monolayers of brain lipid extract.

Understanding protein aggregation is essential to unveil molecular mechanisms associated with neurodegenerative diseases such as Alzheimer's, Huntington's and spongiform encephalopathy, particularly to determine the role of interaction with cell membranes. In this study, we employ Langmuir monolayers as cell membrane models to mimic interaction with the peptide KTNMHKHMAGAAAAGAVVGGLG-OH, a fragment from the human prion protein including residues 106-127, believed to be involved in protein aggregation. Using in situ polarization-modulated infrared reflection adsorption spectroscopy (PM-IRRAS) for Langmuir monolayers and FTIR for solid films, we found that PrP106-127 adopts mainly ß-sheets, random coils and ß-turns in Langmuir monolayers and in Langmuir-Blodgett (LB) and cast films. This also applies to monolayers and solid films made with PrP106-127 and a brain total lipid extract (BTLE). In contrast, some α-helices are observed in the secondary structure of PrP106-127 in monolayers, and especially in solid films, of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). In summary, in a model representing brain cells (BTLE), the secondary structure of PrP106-127 is typical of fiber aggregates, while aggregation is unlikely if PrP106-127 interacts with a membrane model (DOPC) characteristic of mammalian cells.

Magnetic properties of the double perovskites Sm2Mn1+x Co1-x O6 (x = 0, 0.05, 0.12 and 0.26).

The magnetic properties of the double perovskites Sm2Mn1+x Co1-x O6 (x = 0, 0.05, 0.12 and 0.26) were investigated. It was found that the Curie temperature, the lattice parameters and the net magnetic moments increased for increasing amounts of Co. An irreversible behavior was observed by measuring the magnetization after cooling the sample with and without applied magnetic fields (H). The temperature below which the irreversibility was observed is H dependent and the data were nicely fit to de Almeida-Thouless lines. The ac magnetic susceptibility was measured for frequencies f  in the range 0.03-10 kHz yielding [Formula: see text] for the shifting in the freezing temperature per decade of f . The spin-dynamics were found to follow a power-law with a product of the critical exponents [Formula: see text] of about 4.99. The overall results are understood within a framework where the variation in the bonding angle associated to the super-exchange interactions are taken into consideration.

Amifostine reduces inflammation and protects against 5-fluorouracil-induced oral mucositis and hyposalivation.

Oral mucositis (OM) is a common and dose-limiting side effect of cancer treatment, including 5-fluorouracil (5-FU) and radiotherapy. The efficacy of the therapeutic measures to prevent OM is limited and disease prevention is not fully observable. Amifostine is a cytoprotective agent with a described anti-inflammatory potential. It is clinically used to reduce radiotherapy and chemotherapy-associated xerostomia. This study investigated the protective effect of amifostine on an experimental model of OM. Hamsters were divided into six groups: saline control group (5 mL/kg), mechanical trauma (scratches) of the right cheek pouch; 5-FU (60 and 40 mg/kg, ip, respectively, administered on days 1 and 2); amifostine (12.5, 25, or 50 mg/kg) + 5-FU + scratches. Salivation rate was assessed and the animals were euthanized on day 10 for the analysis of macroscopic and microscopic injury by scores. Tissue samples were harvested for the measurement of neutrophil infiltration and detection of inflammatory markers by ELISA and immunohistochemistry. 5-FU induced pronounced hyposalivation, which was prevented by amifostine (P<0.05). In addition, 5-FU injection caused pronounced tissue injury accompanied by increased neutrophil accumulation, tumor necrosis factor-alpha (TNF-α), and interleukin-1 beta (IL-1ß) tissue levels, and positive immunostaining for TNF-α, IL-1ß, and inducible nitric oxide synthase (iNOS). Interestingly, amifostine prevented the inflammatory reaction and consequently improved macroscopic and microscopic damage (P<0.05 vs 5-FU group). Amifostine reduced inflammation and protected against 5-FU-associated oral mucositis and hyposalivation.

Proteic and phenolics compounds contents in Bacupari callus cultured with glutamine and nitrogen sources.

In this study was evaluated the influence of glutamine supplementation on the endogenous content of amino acids, proteins, total phenolics, flavonoids and proanthocyanidins in Bacupari callus. The explants were inoculated in MS medium, MS with half concentration of the nitrogen salts (MS½) and nitrogen-free MS, supplemented with glutamine (5, 10, 30 and 60mM) named as Gln5, Gln10, Gln30 and Gln60. Amino acids and proteins were analyzed after 20, 80 and 140 days and the secondary metabolites on the 140th day. There was no difference in the amino acids on the 20th day. On the 80th day the treatments MS and MS½ presented the lowest levels. On the 140th day MS and MS½ presented the lowest amino acid concentration and Gln10 the highest. Concerning proteins, there was difference only on the 140th day, being the highest concentrations observed in Gln5, and the lowest in MS½ treatment. Total phenolics content was higher in the treatment Gln60 and lowest in MS. Treatments Gln5, Gln10, Gln30 and MS½ were statistically equal. For flavonoids, the highest values occurred in the treatments Gln30, Gln60 and MS½ and the lowest in Gln5, Gln10 and MS. Similarly, for the proanthocyanidins the highest concentrations were observed in treatment Gln60 and the lowest in Gln5 and MS. In conclusion, the treatment with 60mM of glutamine favors the protein accumulation and production of secondary metabolites in Bacupari callus.

Functional Outcomes 18 Months After Total and Midarm Transplantation: A Case Report.

BACKGROUND: The function reported after arm transplantation is deemed beneficial relative to the marked disability that upper arm amputation causes. OBJECTIVE: We report a 51-year-old man with a Disabilities of the Arm, Shoulder and Hand (DASH) score of 75.83 who underwent bilateral arm transplantation in October 2015. PROCEDURE: The right arm was transplanted at the glenohumeral joint level, including transplantation of the humeral head, joint capsule, and rotator cuff ligaments and tendons. Additionally, neurorrhaphies were performed at the origin of the terminal branches of the brachial plexus, including the axillary and musculocutaneous nerves. Therefore, this was considered a total arm transplantation. The left arm was transplanted at the transhumeral level, with complete transplantation of the biceps and triceps brachii, and terminolateral neurorrhaphy of the donor musculocutaneous nerve to the receptor radial nerve. A maintenance triple immunosuppression scheme was administered, with tacrolimus levels kept at 10 ng/mL. RESULTS: At 18 months post-transplantation, the intrinsic musculature in the left hand showed electrical registry, DASH score was 67.5, Carroll test score was 28 in both extremities, Hand Transplant Score System was 67.5 in the right extremity and 77.5 in the left extremity, and Short Form-36 score was 96.1. The patient was healthy, with restored body integrity. He could lift medium-sized weightless objects, eat and go to the bathroom by himself, drink liquids with bimanual grasp, swim, dress almost independently, and drive. CONCLUSION: The functional evolution of the patient was similar to previously reported transplanted arms, even though the right arm transplant involved the glenohumeral joint and axillary and musculocutaneous nerve repair.

5-HT2 and 5-HT3 receptors in the lateral parabrachial nucleus mediate opposite effects on sodium intake.

The present study investigated the role of several 5-HT receptor subtypes in the lateral parabrachial nucleus (LPBN) in the control of sodium appetite (i.e. NaCl consumption). Male Holtzman rats had cannulas implanted bilaterally into the LPBN for the injection of 5-HT receptor agonists and antagonists in conjunction with either acute fluid depletion or 24-h sodium depletion. Following these treatments, access to 0.3 M NaCl was provided and the intakes of saline and water were measured for the next 2 h. Bilateral injections of the 5-HT2A receptor antagonist, ketanserin or the 5-HT2C receptor antagonist, mianserin into the LPBN increased 0.3 M NaCl intake without affecting water intake induced by acute fluid-depletion. Bilateral injections of the 5-HT2B receptor agonist, BW723C86 hydrochloride, had no effect on 0.3 M NaCl or water intake under these conditions. Treatment of the LPBN with the 5-HT2B/2C receptor agonist, 2-(2-methyl-4-clorophenoxy) propanoic acid (mCPP) caused dose-related reductions in 0.3 M NaCl intake after 24 h sodium depletion. The effects of mCPP were prevented by pretreating the LPBN with the 5-HT2B/2C receptor antagonist, SDZSER082. Activation of 5-HT3 receptors by the receptor agonist, 1-phenylbiguanide (PBG) caused dose-related increases in 0.3 M NaCl intake. Pretreatment of the LPBN with the 5-HT3 receptor antagonist, 1-methyl-N-[8-methyl-8-azabicyclo (3.2.1)-oct-3-yl]-1H-indazole-3-carboxamide (LY-278,584) abolished the effects of PBG, but LY-278,584 had no effects on sodium or water intake when injected by itself. PBG injected into the LPBN did not alter intake of palatable 0.06 M sucrose in fluid replete rats. The results suggest that activation of the 5-HT2A and 5-HT2C receptor subtypes inhibits sodium ingestion. In contrast, activation of the 5-HT3 receptor subtype increases sodium ingestion. Therefore, multiple serotonergic receptor subtypes in the LPBN are implicated in the control of sodium intake, sometimes by mediating opposite effects of 5-HT. The results provide new information concerning the control of sodium intake by LPBN mechanisms.

Short-term variability of gamma radiation at the ARM Eastern North Atlantic facility (Azores).

This work addresses the short-term variability of gamma radiation measured continuously at the Eastern North Atlantic (ENA) facility located in the Graciosa island (Azores, 39N; 28W), a fixed site of the Atmospheric Radiation Measurement programme (ARM). The temporal variability of gamma radiation is characterized by occasional anomalies over a slowly-varying signal. Sharp peaks lasting typically 2-4 h are coincident with heavy precipitation and result from the scavenging effect of precipitation bringing radon progeny from the upper levels to the ground surface. However the connection between gamma variability and precipitation is not straightforward as a result of the complex interplay of factors such as the precipitation intensity, the PBL height, the cloud's base height and thickness, or the air mass origin and atmospheric concentration of sub-micron aerosols, which influence the scavenging processes and therefore the concentration of radon progeny. Convective precipitation associated with cumuliform clouds forming under conditions of warming of the ground relative to the air does not produce enhancements in gamma radiation, since the drop growing process is dominated by the fast accretion of liquid water, resulting in the reduction of the concentration of radionuclides by dilution. Events of convective precipitation further contribute to a reduction in gamma counts by inhibiting radon release from the soil surface and by attenuating gamma rays from all gamma-emitting elements on the ground. Anomalies occurring in the absence of precipitation are found to be associated with a diurnal cycle of maximum gamma counts before sunrise decreasing to a minimum in the evening, which are observed in conditions of thermal stability and very weak winds enabling the build-up of near surface radon progeny during the night.