Impact of the Curing Temperature on the Manufacturing Process of Multi-Nanoparticle-Reinforced Epoxy Matrix Composites

This study aims to analyze the effect of the curing temperature of nano-reinforcements during the manufacturing process on the mechanical properties of composites involving graphene (GNP), carbon nanofibers (CNFs), and a hybrid mixture of these two nanoparticles. In this context, the type of nanoparticles, their content, their type of resin, and their hybridization were considered. The results showed that both nanoparticles increased the viscosity of the resin suspension, with an increase of between 16.3% and 38.2% for GNP nanoparticles and 45.4% and 74% for CNFs depending on the type of resin. Shrinkage was also affected by the addition of nanoparticles, as the highest results were obtained with GNP nanoparticles, with a 91% increase compared with the neat resin, and the lowest results were obtained with CNFs, with a decrease of 77% compared with the neat resin. A curing temperature of 5 °C promoted the best bending and hardness performance for all composites regardless of the type of resin and reinforcement used, with improvements of up to 24.8% for GNP nanoparticles and 13.52% for CNFs compared with the neat resin at 20 °C. Hybridization led to further improvements in bending properties and hardness compared with single-reinforcement composites due to a synergistic effect. However, the effectiveness of hybridization depends on the type of resin.

Whole-plant flint corn silage inclusion in total mixed rations for pre- and postweaning dairy calves

Assuming that acetic acid plays a minor role in the development of ruminal epithelium of preweaning dairy calves, the fiber supply for growing calves has been neglected. More research has been done on including starch and nonfibrous carbohydrates in solid feed for preweaning calves. Accordingly, the fiber requirement of these calves is not well known, as diet recommendations vary greatly. Hence, elucidating the effects of including fiber from long particle sizes in the diet may be essential for helping calves overcome the transition challenge during weaning. Forty-five Holstein calves were used in a randomized block design, considering sex, birth date, and weight at 28 d of age, when the supply of the total mixed ration (TMR) with the inclusion of corn silage started. Three TMR with increasing whole-plant flint corn silage content (0, 10, or 20% on a dry matter basis) were compared: 0CS, 10CS, or 20CS, respectively. During the first 28 d of life, the calves were managed homogeneously and were fed 6 L/d of whole milk, a commercial calf starter pelleted, and water ad libitum. Next, the solid diet was changed to the respective solid feed treatment. Calves were gradually weaned from 52 to 56 d of age but were evaluated for an additional 14 d postweaning. Feed intake was measured daily, while body weight and metabolic indicators of intermediate metabolism were evaluated weekly. Ruminal fluid was collected at 6, 8, and 10 wk of age. Behavioral analysis was conducted on wk 7 (preweaning) and 10 (postweaning). There was a quadratic effect for dry matter intake from wk 7 to 10, with higher intake for the 10CS diet than the 0CS and 20CS diets. Consequently, the 10CS diet also promoted greater average daily gain at wk 8 and 9 compared with the 0CS and 20CS diets. However, the final body weight was not affected by the different solid diets. Silage inclusion in calves' diet positively affected time spent ruminating and chewing pre- and postweaning. Including 10% of whole-plant flint corn silage in the diets of young dairy calves is a strategy to increase total solid intake and decrease acidosis risk by increasing pH and ruminating activity around weaning.

Climate-induced variability in South Atlantic wave direction over the past three millennia

Through alteration of wave-generating atmospheric systems, global climate changes play a fundamental role in regional wave climate. However, long-term wave-climate cycles and their associated forcing mechanisms remain poorly constrained, in part due to a relative dearth of highly resolved archives. Here we use the morphology of former shorelines preserved in beach-foredune ridges (BFR) within a protected embayment to reconstruct changes in predominant wave directions in the Subtropical South Atlantic during the last ~ 3000 years. These analyses reveal multi-centennial cycles of oscillation in predominant wave direction in accordance with stronger (weaker) South Atlantic mid- to high-latitudes mean sea-level pressure gradient and zonal westerly winds, favouring wave generation zones in higher (lower) latitudes and consequent southerly (easterly) wave components. We identify the Southern Annular Mode as the primary climate driver responsible for these changes. Long-term variations in interhemispheric surface temperature anomalies coexist with oscillations in wave direction, which indicates the influence of temperature-driven atmospheric teleconnections on wave-generation cycles. These results provide a novel geomorphic proxy for paleoenvironmental reconstructions and present new insights into the role of global multi-decadal to multi-centennial climate variability in controlling coastal-ocean wave climate.

Red propolis as an additive for preweaned dairy calves: Effect on growth performance, health, and selected blood parameters

Propolis is a natural product produced by bees and sold commercially. It is well known for its antioxidant and anti-inflammatory effects and the ability to improve immune system functions in humans and animals. Many of its positive effects can contribute positively to animal productivity. The aim of this study was to evaluate possible beneficial effects of red propolis supplementation on growth performance, metabolism, and health status of dairy calves during the preweaning phase. Thirty-two newborn calves were individually housed, with free access to water and concentrate, and fed 6 L/d of whole milk. Animals were distributed in 2 treatments: (1) control and (2) supplementation with 4 mL/d of red propolis ethanolic extract (30%; EEP) in whole milk. Feed consumption and fecal and health scores were monitored daily from 1 d of age to 56 d. Calves were weighed and measured weekly. Blood samples were collected weekly, 2 h after morning milk feeding, for determination of glucose, total serum protein, urea, lactate, β-hydroxybutyrate, total iron binding capacity, and total leukocytes (white blood cells) and erythrocytes (red blood cells). Starter feed intake, daily weight gain, and body measurements were not affected by the EEP supplementation. Blood parameters were also not affected, with the exception for the red blood cell counts, which were lower in animals supplemented with EEP. Supplementation with EEP significantly decreased fecal score, days with diarrhea, and veterinary treatments of diarrhea. These results indicate that red propolis supplementation has potential to improve calf health and reduce the incidence of diarrhea and, as a consequence, the use of antibiotics in calf rearing systems.

Monensin and a blend of castor oil and cashew nut shell liquid used in a high-concentrate diet abruptly fed to Nellore cattle

Monensin and functional oils (FO) were supplemented to a high-concentrate diet abruptly fed to 12 ruminally cannulated Zebu steers to study their effects on rumen fermentation, blood metabolites, and , , and relative population. A randomized complete block design with repeated measures over time within 2 experimental periods of 21 d each was used. Treatments were a control (CTR; with no additives), FO (included at 400 mg/kg), and monensin included at 30 mg/kg (M30) or 40 mg/kg (M40). All steers were fed the same high-concentrate basal diet, which consisted of 92.25% concentrate. The first 60 h after transition showed a treatment and hour interaction for ruminal propionate proportion ( = 0.028), and no change in acetate molar proportion ( = 0.633), rumen pH ( = 0.370), and time the rumen pH remained below 5.6 ( = 0.242) were observed. The acetate:propionate ratio decreased ( = 0.020) when monensin was fed in both concentrations (2.30 for the M30 treatment and 2.32 for the M40 treatment) compared with when the CTR was fed (2.85), without being different when the FO (2.71) treatment was fed. Only the M30 treatment did not show pH below 5.2 (P=0.047) over the 60 h after the abrupt transition. Within the entire period, DMI ( = 0.008) and mean ruminal pH ( = 0.040) as well as molar proportions of propionate ( = 0.034) and valerate ( = 0.031) had significant interactions between treatment and day. Total VFA concentration was greater ( = 0.017) for the M30 (117.36 m) and CTR treatments (115.77 m) compared with the M40 treatment (105.02 m), without being different for the FO treatment (111.55 m). Treatments did not change feed behavior parameters. Blood HCO ( = 0.006) and total carbon dioxide ( = 0.003) were greater for the M30 (27.8 and 29.3 mmol/L, respectively) and FO treatments (28.3 and 29.7 mmol/L, respectively) compared with the CTR treatment (25.7 and 26.9 mmol/L, respectively). ( < 0.0001) and ( < 0.0001) decreased their population throughout days, whereas ( = 0.026) increased its population. Independent of ciliated protozoa genera, the greatest ( < 0.0001) protozoa counts were observed for the CTR treatment (52.7 × 10/mL), intermediate for the FO treatment (35.3 x10/mL), and least for steers fed monensin in both concentrations (15 × 10/mL for the M30 treatment and 14 × 10/mL for the M40 treatment). Feed additives had different effects to reduce the subacute acidosis. The use of the FO and M40 treatments did not change most of the rumen fermentation variables, especially in the first week after abrupt transition, when the M30 treatment provided higher protection against acidosis.

Impact of ERG3 mutations and expression of ergosterol genes controlled by UPC2 and NDT80 in Candida parapsilosis azole resistance

OBJECTIVES

Candida parapsilosis is a healthcare-related fungal pathogen particularly common among immunocompromised patients. Our understanding of antifungal resistance mechanisms in C. parapsilosis remains very limited. We previously described an azole-resistant strain of C. parapsilosis (BC014R_PSC), obtained following exposure in vitro to posaconazole. Resistance was associated with overexpression of ergosterol biosynthetic genes (ERG genes), together with the transcription factors UPC2 (CPAR2-207280) and NDT80 (CPAR2-213640). The aim of this study was to identify the mechanisms underlying posaconazole resistance of the BC014R_PSC strain.

METHODS

To identify the causative mutation, we sequenced the genomes of the susceptible (BC014S) and resistant (BC014R_PSC) isolates, using Illumina technology. Ergosterol content was assessed in both strains by mass spectrometry. UPC2 and NDT80 genes were deleted in BC014R_PSC strain. Mutants were characterized regarding their azole susceptibility profile and ERG gene expression.

RESULTS

One homozygous missense mutation (R135I) was found in ERG3 (CPAR2-105550) in the azole-resistant isolate. We show that Erg3 activity is completely impaired, resulting in a build up of sterol intermediates and a failure to generate ergosterol. Deleting UPC2 and NDT80 in BC014R_PSC reduces the expression of ERG genes and restores susceptibility to azole drugs.

CONCLUSIONS

A missense mutation in the ERG3 gene results in azole resistance and up-regulation of ERG genes expression. We propose that this mutation prevents the formation of toxic intermediates when cells are treated with azoles. Resistance can be reversed by deleting Upc2 and Ndt80 transcription factors. UPC2 plays a stronger role in C. parapsilosis azole resistance than does NDT80.

Starch characterization in seven raw, boiled and roasted chestnuts (Castanea sativa Mill.) cultivars from Portugal

Changes occurring in seven chestnut (Castanea sativa sp.) cultivars, caused by boiling and roasting, on starch content, cell and starch granules dimension were evaluated, and morphological changes were characterized by scanning electron microscopy. Three clear patterns of variation were detected after processing, namely: i) decrease of starch content with processing; ii) starch increase with the applied treatments; iii) increase of starch with boiling and decrease with roasting. Starch granules of raw chestnuts presented round, oval or elliptical form, external smooth surface and eccentric hilum, with rather ellipsoid-shaped growth rings. Processing resulted in modifications of the granules, with fusion of individual granules, and gelatinization taking place with the formation of elongated clusters. The present results indicate that boiling and roasting, besides changing the starch content of chestnut, causes important modifications in the starch granules, which can affect the sensory, rheological and chemical characteristics of chestnuts.

Long-time monitoring of polychlorinated dibenzo-p-dioxins and dibenzofurans over a decade in the ambient air of Porto, Portugal

As part of a monitoring program initiated in 1998 and conducted by IDAD - Institute for Environment and Development and supported by regional municipal solid waste (MSW) management authorities, an extensive database of dioxins' and furans' (PCDD/PCDF) concentrations in ambient air was collected in Porto, in two sites classified as suburban. The present paper summarizes the analytical results of PCDD/PCDF in ambient air obtained from 2001 to 2014 through this intensive monitoring work. The toxic equivalent (WHO-TEQ 1998) concentrations of the PCDD/PCDF in the air ranged from 8.2 to 904.4 fg TEQ m(-3), with an average and median values of 104.5 fg TEQ m(-3) and 49.8 fg TEQ m(-3), respectively. The PCDD/PCDF concentration trend in Porto's ambient air shows a clear drop of the annual average values occurred during the study period. The presence of seasonal variations is very clear in the present study. Winter levels (average: 154.3 fg TEQ m(-3)) are significantly higher than summer levels (average: 42.9 fg TEQ m(-3)). The PCDD/PCDF profiles' details show that several differences occurred over time. The homologue profiles presented changes and the PCDD congeners have decreased in terms of mass. The analysis of concentrations in combination with specific homologue and congener patterns of PCDD/PCDF allowed identification of potential emission sources.

Seasonal variation of bacterial communities in shellfish harvesting waters: preliminary study before applying phage therapy

The recurrent emergence of infections outbreaks associated with shellfish consumption is an important health problem, which results in substantial economic losses to the seafood industry. Even after depuration, shellfish is still involved in outbreaks caused by pathogenic bacteria, which increases the demand for new efficient strategies to control the shellfish infection transmission. Phage therapy during the shellfish depuration is a promising approach, but its success depends on a detailed understanding of the dynamics of bacterial communities in the harvesting waters. This study intends to evaluate the seasonal dynamics of the overall bacterial communities, disease-causing bacterial populations and bacterial sanitary quality indicators in two authorized harvesting-zones at Ria de Aveiro. During the hot season, the total bacterial community presented high complexity and new prevalent populations of the main shellfish pathogenic bacteria emerged. These results indicate that the spring/summer season is a critical period during which phage therapy should be applied.

Bioactive polymeric-ceramic hybrid 3D scaffold for application in bone tissue regeneration

The regeneration of large bone defects remains a challenging scenario from a therapeutic point of view. In fact, the currently available bone substitutes are often limited by poor tissue integration and severe host inflammatory responses, which eventually lead to surgical removal. In an attempt to address these issues, herein we evaluated the importance of alginate incorporation in the production of improved and tunable β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) three-dimensional (3D) porous scaffolds to be used as temporary templates for bone regeneration. Different bioceramic combinations were tested in order to investigate optimal scaffold architectures. Additionally, 3D β-TCP/HA vacuum-coated with alginate, presented improved compressive strength, fracture toughness and Young's modulus, to values similar to those of native bone. The hybrid 3D polymeric-bioceramic scaffolds also supported osteoblast adhesion, maturation and proliferation, as demonstrated by fluorescence microscopy. To the best of our knowledge this is the first time that a 3D scaffold produced with this combination of biomaterials is described. Altogether, our results emphasize that this hybrid scaffold presents promising characteristics for its future application in bone regeneration.

Multifaces of neuropeptide Y in the brain--neuroprotection, neurogenesis and neuroinflammation

Neuropeptide Y (NPY) has been implicated in the modulation of important features of neuronal physiology, including calcium homeostasis, neurotransmitter release and excitability. Moreover, NPY has been involved as an important modulator of hippocampal and thalamic circuits, receiving particular attention as an endogenous antiepileptic peptide and as a potential master regulator of feeding behavior. NPY not only inhibits excessive glutamate release (decreasing circuitry hyperexcitability) but also protects neurons from excitotoxic cell death. Furthermore, NPY has been involved in the modulation of the dynamics of dentate gyrus and subventricular zone neural stem cell niches. In both regions, NPY is part of the chemical resource of the neurogenic niche and acts through NPY Y1 receptors to promote neuronal differentiation. Interestingly, NPY is also considered a neuroimmune messenger. In this review, we highlight recent evidences concerning paracrine/autocrine actions of NPY involved in neuroprotection, neurogenesis and neuroinflammation. In summary, the three faces of NPY, discussed in the present review, may contribute to better understand the dynamics and cell fate decision in the brain parenchyma and in restricted areas of neurogenic niches, in health and disease.

PP159. In women with previous pregnancy hypertension, cardiovascular risk biomarkers may be modulated by haptoglobin genotype

INTRODUCTION

Preeclampsia may affect the risk for future cardiovascular disease. Haptoglobin (Hp), an acute phase protein with genetic polymorphism (Hp1.1, 2.1 and 2.2) synthesized in the hepatocyte and in many tissues, may modulate the risk through the antioxidant and anti-inflammatory differential effects of their genotypes.

OBJECTIVES

Evaluate some parameters of cardiovascular risk in association with genetic polymorphism of Hp in women with previous preeclampsia (HBP) compared to healthy women during gestation (NBP).

METHODS

We studied 352 women aged 35±5.48 current year, taking these, 165 presented previous preeclampsia, 2-14 (±6.6) years ago. Genetic polymorphism of Hp was determined from plasma by electrophoresis. The different circulating biomarkers, myeloperoxidase ng/mL (MPO) and nitrates and nitrites (nmol/ml) by ELISA, transaminases - AST and ALT (U/L) and apolipoprotein A and B (mg/dL), uric acid (mg/dl) hs-CRP (mg/L) were determined by conventional methods as well as blood pressure (BP) and anthropometric parameters BMI and hip and waist circumference (WC).Statistical methods were Chi-square, ANOVA (Bonferroni) and t-Student.

RESULTS

There were no differences in the distribution of phenotypes of Hp between NBP and those with previous hypertension in pregnancy. There were differences between NBP and HBP in the following parameters: Systolic BP (118.9±13.4 vs 135.0±16.5, p<0.001); Diastolic BP (72.2±10.1 vs 85.9±12.0 p<0.001); MPO (62.3±30.9 vs 85.7±39.4, p=0.020); Nitrite (10.1±3.8 vs 19.1±7.0, p<0.001); ALT (18.0±8.0 vs 22.5±12.9, p=0.016); BMI (25.4±4.1 vs 27.1±4.8, p=0.031); WC (82.8±9.9 vs 89.5±15.6, p=0.002); Apo B (0.6±0.1 vs 0.6±0.1, p=0.023). Those values vary with the genotypes of Hp and were observed Hp 1.1 and 2.1 in NBP and HBP respectively: [Systolic BP 119.2±13.7 vs 134.7±18.3 (p<0.001); Diastolic BP (72.8±11.9 vs 86.2±19.4 p<0.001); MPO (57.9±32.5 vs 94.2±42.1, p=0.008); Nitrites (9.6±3.2 vs 20.0±8.5, p<0.001); ALT(17.0±7.2 vs 20.4±8.0, p=0.033); WC (82.4±10.0 vs 90.8±17.6, p=0.004); Apo A (0.9±0.2 vs 1.0±0.2, p=0.011)] and Hp 2.2 in NBP and HBP respectively: [Systolic BP 118.2±13.1 vs 135.6±12.8 (p<0.001); Diastolic BP (70.9±7.2 vs 85.5±16.3 p<0.001); Nitrites (11.5±5.1 vs 18.0±4.4, p<0.001)].

CONCLUSION

Women with previous hypertension during pregnancy, presented significant differences in some classic cardiovascular risk biomarkers as well as in some others, associated with the inflammatory process, whose variation may be modulated by haptoglobin functional genetic polymorphism. The history of hypertensive disease in pregnancy may be relevant, in association with these biomarkers to the prevention of cardiovascular disease in particular of postmenopausal women.

May exercise prevent addiction?

Amphetamines exert their persistent addictive effects by activating brain's reward pathways, perhaps through the release of dopamine in the nucleus accumbens (and/or in other places). On the other hand, there is a relationship between dopamine and all behavioural aspects that involve motor activity and it has been demonstrated that exercise leads to an increase in the synthesis and release of dopamine, stimulates neuroplasticity and promotes feelings of well-being. Moreover, exercise and drugs of abuse activate overlapping neural systems. Thus, our aim was to study the influence of chronic exercise in the mechanism of addiction using an amphetamine-induced conditioned-place-preference in rats.

Adult male Sprague-Dawley rats were randomly separated in groups with and without chronic exercise. Chronic exercise consisted in a 8 week treadmill running program, with increasing intensity. The conditioned place preference test was performed in both groups using a procedure and apparatus previously established. A 2 mg.kg^-1 amphetamine or saline solution was administered intraperitonially according to the schedule of the conditioned place preference.

Before conditioning none of the animals showed preference for a specific compartment of the apparatus. The used amphetamine dose in the conditioning phase was able to produce a marked preference towards the drug-associated compartment in the group without exercise. In the animals with exercise a significant preference by the compartment associated with saline was observed.

These results lead us to conclude that a previous practice of regular physical activity may help preventing amphetamine addiction in the conditions used in this test.

Candida krusei reservoir in a neutropaenia unit: molecular evidence of a foe?

Candida krusei has been documented as an emerging pathogen causing nosocomial outbreaks. The consecutive isolation of C. krusei strains in three patients admitted to the same hospital department within 2 months lead us to consider the possibility of an outbreak. Additionally, C. krusei isolates were collected from the room surfaces, whereas another isolate had been recovered from the blood of one patient 2 years before. HinfI DNA restriction endonuclease-based analysis of all C. krusei isolates was performed and restriction profiles were compared. Surprisingly, isolates from different patients were unrelated, whereas isolates from biological products of the same patient showed indistinguishable HinfI restriction patterns and were similar to those obtained from the surrounding environment of the respective patients. The study approach revealed the endogenous origin of the C. krusei infectious episodes observed and demonstrated that, subsequent to colonizing a patient, C. krusei can be involved in infectious episodes distant in time. The hypothesis of an outbreak was excluded, although we believe that the methodology employed in the present study represents a valuable tool for diagnostic and epidemiological surveys.

Pupal development of Ceratitis capitata (Diptera: Tephritidae) and Diachasmimorpha longicaudata (Hymenoptera: Braconidae) at different moisture values in four soil types

This study aimed to evaluate adult emergence and duration of the pupal stage of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and emergence of the fruit fly parasitoid, Diachasmimorpha longicaudata (Ashmead), under different moisture conditions in four soil types, using soil water matric potential. Pupal stage duration in C. capitata was influenced differently for males and females. In females, only soil type affected pupal stage duration, which was longer in a clay soil. In males, pupal stage duration was individually influenced by moisture and soil type, with a reduction in pupal stage duration in a heavy clay soil and in a sandy clay, with longer duration in the clay soil. As matric potential decreased, duration of the pupal stage of C. capitata males increased, regardless of soil type. C. capitata emergence was affected by moisture, regardless of soil type, and was higher in drier soils. The emergence of D. longicaudata adults was individually influenced by soil type and moisture factors, and the number of emerged D. longicaudata adults was three times higher in sandy loam and lower in a heavy clay soil. Always, the number of emerged adults was higher at higher moisture conditions. C. capitata and D. longicaudata pupal development was affected by moisture and soil type, which may facilitate pest sampling and allow release areas for the parasitoid to be defined under field conditions.

Solitary hemangioma of the small bowel disclosed by wireless capsule endoscopy

A nine-year-old child presented with melena and anemia. She had similar symptoms five months earlier and had undergone an extensive workup with upper gastrointestinal endoscopy and colonoscopy, both normal and 99m-Tc-RBC-scintigraphy which was positive in the right lower quadrant. This time, capsule endoscopy was performed and disclosed an hemangioma with a dark spot suggesting recent bleeding in the ileum. The lesion was resected. Pathological examination revealed a transmural cavernous hemangioma. Small bowel hemangioma is a rare disease. Its diagnosis is extremely difficult and is usually obtained during surgery. Capsule endoscopy is an endoscopic technique that can improve preoperative diagnosis, as reported in the present case.

Autonomy and susceptibility to HIV/AIDS among young women living in a slum in Belo Horizonte, Brazil

In Brazil in the last decade there has been an increase in the susceptibility of young women to HIV. This study explored the link between autonomy, or control over major domains of economic, social and sexual life, and susceptibility to HIV infection among poor young women living in an urban slum area of Brazil. A cross-sectional survey was carried out on a random sample of 356 young women between 15 and 24 years old. The study found that indicators of autonomy that relate to sexuality, mobility and freedom from threat by partners were significantly correlated with practices linked to HIV prevention and with access to health services promoting prevention, especially among adolescents. Young women who talked to their partner about condom use before first intercourse and co-decided with them on condom use were more likely to use condoms. In contrast, those who had ever been victim of physical violence by a partner or whose partners restricted their mobility were less likely to use condoms. The study found that young women were more likely to have accessed health services for gynaecological examinations, family planning services and HIV testing if they had ever been pregnant. The findings indicate that structural gender inequalities translate into unequal relationships and reduced autonomy, increasing young women's susceptibility to HIV. A bias in HIV testing and reproductive health services towards pregnant women leaves many susceptible youth without early access. The study suggests the development of a reproductive health policy that ensures that young women access services before they get pregnant and that also reaches young males.

Neuropeptide Y can rescue neurons from cell death following the application of an excitotoxic insult with kainate in rat organotypic hippocampal slice cultures

In the present work we investigated the neuroprotective role of neuropeptide Y (NPY) after an excitotoxic insult in rat organotypic hippocampal slice cultures. Exposure of 2 week-old rat hippocampal slice cultures to 12muM kainate (KA) for 24h induced neuronal death in dentate gyrus (DG) granular cell layer, CA1 and CA3 pyramidal cell layers, as quantified by cellular propidium iodide (PI) uptake. The activation of Y(1) or Y(2) receptors 30min after starting the exposure to the excitotoxic insult with kainate resulted in neuroprotection by reducing the PI uptake in DG, CA1 and CA3 cell layers. The use of Y(1) or Y(2) receptors antagonists, BIBP3226 (1muM) or BIIE0246 (1muM), resulted in the loss of the neuroprotection induced by the activation of Y(1) or Y(2) receptors, respectively, in all hippocampal subfields. Taken together these results suggest that activation of NPY Y(1) or Y(2) receptors activates neuroprotective pathways that are able to rescue neurons from excitotoxic cell death.

Nutritional and inflammatory status influence darbepoetin dose in pre-dialysis elderly patients

Anaemia is a common finding in elderly patients particularly in those with chronic kidney disease. Effective correction of anaemia improves survival and quality of life. The association between anaemia and a poor nutritional status as well as the presence of inflammation has already been documented. The aim of our study was to assess the impact of the nutritional and inflammatory status on darbepoetin dose requirements of elderly patients followed in a "Chronic Kidney Disease" outpatient clinic. We included 71 elderly patients (age>or=65 years) in a "Chronic Kidney Disease" outpatient clinic. Creatinine Clearance (CrCl) was estimated according to the Cockroft-Gault equation. Nutritional status was evaluated by biochemical and anthropometric parameters. Tumour Necrosis Factor-alpha (TNF-alpha), Interleukin-6 (IL-6) and high sensitivity C-reactive protein (hs-CRP) were used as biomarkers of inflammation. Our patients (56% males) with a mean age of 76.2+/-6.6 years were followed for 33.1+/-43.6 months. Mean eCrCl was 13.5+/-7.2 ml/mn/1.73 m2. All patients were under supplemental iron therapy and 74.7% needed darbepoietin (0.762+/-0.6 (microg/kg/week) to correct anaemia. Among the several variables regressed on darbepoietin dose, in a multiple regression model, only Hb, IL-6 and TNF-alpha levels and SGA score predicted the need for higher doses of darbepoietin. (r=0.677; r2=0.459). In Conclusion, in our pre-dialysis elderly patients, markers of a poor nutritional status (SGA and albumin) and inflammation (IL-6 and TNF-alpha) independently predicted the use of higher doses of darbepoietin to correct anaemia.

Plasmodium yoelii: the effect of second blood meal and anti-sporozoite antibodies on development and gene expression in the mosquito vector, Anopheles stephensi

The sporogonic development of the malaria parasite takes place in the mosquito and a wide range of factors modulates it. Among those, the contents of the blood meal can influence the parasite development directly or indirectly through the mosquito response to the infection. We have studied the effect of a second blood meal in previously infected mosquitoes and the effect of anti-sporozoite immune serum on parasite development and mosquito response to the infection. The prevalence and intensity of infection and gene expression of both Plasmodium yoelii and Anopheles stephensi was analyzed. We verified that a second blood meal and its immune status interfere with parasite development and with Plasmodium and mosquito gene expression.

Regulation of CRH-induced secretion of ACTH and corticosterone by SOM230 in rats

OBJECTIVE

Adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome is biochemically characterized by increased plasma concentrations of ACTH inducing hypersecretion of cortisol. Somatostatin is known to inhibit ACTH secretion, and in vitro data have shown the inhibition of ACTH secretion by agonists activating sst2 and sst5 receptors. The present study aimed to determine the inhibitory effect of the multireceptor ligand SOM230, compared with the sst2-preferring agonist octreotide, on corticotropin-releasing hormone (CRH)-stimulated secretion of ACTH and corticosterone in rats.

METHODS

Secretion of ACTH and corticosterone was induced by i.v. application of CRH (0.5 microg/kg) in rats pretreated 1 h before by i.v. application of SOM230 (1, 3, or 10 microg/kg), octreotide (10 microg/kg) or NaCl 0.9%.

RESULTS

SOM230 (3 and 10 microg/kg) inhibited CRH-induced ACTH release by 45+/-3% and 51+/-2%, respectively, and corticosterone release by 43+/-5% and 27+/-16%, respectively. 10 microg/kg of octreotide tended to be less potent at inhibiting ACTH release (34+/-6% inhibition) and did not alter the secretion of corticosterone.

CONCLUSION

SOM230 has a stronger inhibitory effect on ACTH and corticosterone secretion than octreotide in rats. This difference can be explained by its higher affinity to sst1, sst3 and especially sst5 receptors compared with octreotide.

Short- and long-term effects of octreotide and SOM230 on GH, IGF-I, ACTH, corticosterone and ghrelin in rats

SOM230 is a novel somatostatin analog which shows affinity to 4 of the 5 known somatostatin receptors (SSTR1-5). In binding experiments, SOM230 has a higher affinity to SSTR1, SSTR3 and SSTR5 and a slightly lower affinity to SSTR2 compared to octreotide. In addition, SOM230 has a >7-fold longer plasma half-life than octreotide (11 vs 1.5 h). It was suggested that SOM230 with its broader binding and activity profile compared to octreotide should have a stronger (usually inhibitory) effect on the secretion of hormones. In several animal species, SOM230 was a more potent inhibitor of GH and IGF-I than octreotide. This is in line with a strong expression of both SSTR2 and SSTR5. In the pituitary of patients with primary Cushing's disease, the SSTR5 is more frequently expressed than SSTR2. Accordingly, in rats SOM230 caused a stronger inhibition of ACTH and corticosterone secretion than octreotide. In contrast, most recent experiments showed that octreotide was more potent than SOM230 to inhibit ghrelin secretion in rats. This effect could be explained by the strong expression of SSTR2 in the rat stomach, whereas expression of SSTR3, SSTR4 and SSTR5 was poor or absent. Based on these data it can be concluded that in tissues (or tumors), where several SSTRs are expressed, SOM230 will generally have a stronger effect than octreotide. In cases where SSTR2 is the most important receptor mediating a response (e.g. ghrelin release in rats), the stronger inhibitory effect of octreotide can be explained by its higher affinity for SSTR2. In contrast to the long-lasting inhibitory effect of SOM230 on GH and IGF-I secretion, the inhibitory effects of both compounds on ghrelin show strong tachyphylaxis. These data are in line with the hypothesis that activation of the SSTR2 alone results in a rapid desensitization of the response. If, however, additional SSTR subtypes (especially SSTR5) are expressed and activated by multiligand analogs like SOM230, this might not only form the basis for a stronger response, but also the basis for a reduced tachyphylaxis.

NPY regulates catecholamine secretion from human adrenal chromaffin cells

The aim of the present work was to find out whether NPY synthesized in human adrenal chromaffin cells controls in an autocrine/paracrine fashion the release of catecholamines by these cells. Accordingly, the constitutive and regulated release of both NPY and catecholamines was measured simultaneously in cultured human chromaffin cells. In addition, by using both RT-PCR and a combination of specific agonists and antagonists, we characterized the expression of NPY receptors on these cells as well as their pharmacology. Our results were as follows. 1) Human chromaffin cells constitutively secrete NPY. 2) Nicotine elicits a rapid increase in the release of both catecholamines and NPY; this release of NPY is more sustained than that of catecholamines. 3) RT-PCR shows expression of Y1, Y2, Y4, and Y5 receptor mRNA by chromaffin cells; these receptors are functional, as various receptor specific agonists elicit an increase in intracellular calcium. 4) Peptide YY, in contrast to NPY, is not able to stimulate the release of catecholamines. This finding was corroborated by the observation that no receptor-specific antagonists were able to reduce constitutive catecholamine release, whereas an NPY-immunoneutralizing antibody markedly attenuated the secretion. Taken together, these data suggest that NPY originating from the adrenal medulla locally enhances the secretion of catecholamines, presumably by acting via the putative y3 receptor.

Modulation of intracellular calcium changes and glutamate release by neuropeptide Y1 and Y2 receptors in the rat hippocampus: differential effects in CA1, CA3 and dentate gyrus

In the present work, we investigated the role of pre- and post-synaptic neuropeptide Y1 (NPY1) and Y2 receptors on the calcium responses and on glutamate release in the rat hippocampus. In cultured hippocampal neurones, we observed that only NPY1 receptors are involved in the modulation of intracellular free calcium concentration ([Ca(2+)](i)). In 88% of the neurones analysed, the increase in the [Ca(2+)](i), in response to depolarization with 50 mM KCl, was inhibited by 1 microM [Leu31,Pro34]NPY, whereas 300 nM NPY13-36 was without effect. However, studies with hippocampal synaptosomes showed that both NPY1 and Y2 receptors can modulate the [Ca(2+)](i) and glutamate release. The pharmacological characterization of the NPY-induced inhibition of glutamate release indicated that Y2 receptors play a predominant role, both in the modulation of Ca(2+)-dependent and -independent glutamate release. However, we could distinguish between Y1 and Y2 receptors by using [Leu31,Pro34]NPY and NPY13-36. Active pre-synaptic Y1 receptors are present in the dentate gyrus (DG) as well as in the CA3 subregion, but its activity was not revealed by using the endogenous agonist, NPY. Concerning the Y2 receptors, they are present in the three subregions (CA1, CA3 and DG) and were activated by either NPY13-36 or NPY. The present data support a predominant role for NPY2 receptors in mediating NPY-induced inhibition of glutamate release in the hippocampus, but the physiological relevance of the presently described DG and CA3 pre-synaptic NPY1 receptors remains to be clarified.

Role of kainate receptor activation and desensitization on the [Ca(2+)](i) changes in cultured rat hippocampal neurons

We investigated the role of kainate (KA) receptor activation and desensitization in inducing the increase in the intracellular free Ca(2+) concentration ([Ca(2+)](i)) in individual cultured rat hippocampal neurons. The rat hippocampal neurons in the cultures were shown to express kainate receptor subunits, KA2 and GluR6/7, either by immunocytochemistry or by immunoblot analysis. The effect of LY303070, an alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionate (AMPA) receptor antagonist, on the alterations in the [Ca(2+)](i) caused by kainate showed cell-to-cell variability. The [Ca(2+)](i) increase caused by kainate was mostly mediated by the activation of AMPA receptors because LY303070 inhibited the response to kainate in a high percentage of neurons. The response to kainate was potentiated by concanavalin A (Con A), which inhibits kainate receptor desensitization, in 82.1% of the neurons, and this potentiation was not reversed by LY303070 in about 38% of the neurons. Also, upon stimulation of the cells with 4-methylglutamate (MGA), a selective kainate receptor agonist, in the presence of Con A, it was possible to observe [Ca(2+)](i) changes induced by kainate receptor activation, because LY303070 did not inhibit the response in all neurons analyzed. In toxicity studies, cultured rat hippocampal neurons were exposed to the drugs for 30 min, and the cell viability was evaluated at 24 hr using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The selective activation of kainate receptors with MGA, in the presence of Con A, induced a toxic effect, which was not prevented by LY303070, revealing a contribution of a small subpopulation of neurons expressing kainate receptors that independently mediate cytotoxicity. Taken together, these results indicate that cultured hippocampal neurons express not only AMPA receptors, but also kainate receptors, which can modulate the [Ca(2+)](i) and toxicity.

Inhibition of glutamate release by BIA 2-093 and BIA 2-024, two novel derivatives of carbamazepine, due to blockade of sodium but not calcium channels

We investigated the mechanism(s) of action of two new putative antiepileptic drugs (AEDs), (S)-(-)-10-acetoxy-10,11-dihydro-5H-dibenz[b,f]azepine-5-carboxamide (BIA 2-093) and 10,11-dihydro-10-hydroxyimino-5H-dibenz[b,f]azepine-5-carboxamide (BIA 2-024), by comparing their effects on the release of endogenous glutamate in hippocampal synaptosomes, with those of carbamazepine (CBZ) and oxcarbazepine (OXC). The AEDs inhibited the release of glutamate evoked by 4-aminopyridine (4-AP) or veratridine in a concentration-dependent manner, being CBZ more potent than the other AEDs. Using conditions of stimulation (30 mM KCl), where Na(+) channels are inactivated, the AEDs did not inhibit either the Ca(2+)-dependent or -independent release of glutamate. The results indicate that BIA 2-093 and BIA 2-024 have sodium channel-blocking properties, but CBZ and OXC are more potent than the new AEDs. Moreover, the present data also indicate that Ca(2+) channels coupled to the exocytotic release of glutamate and the activity of the glutamate transporter were not affected by the AEDs.

Neurotoxic/neuroprotective profile of carbamazepine, oxcarbazepine and two new putative antiepileptic drugs, BIA 2-093 and BIA 2-024

We investigated and compared the toxicity profile, as well as possible neuroprotective effects, of some antiepileptic drugs in cultured rat hippocampal neurons. We used two novel carbamazepine derivatives, (S)-(-)-10-acetoxy-10,11-dihydro-5H-dibenz[b, f]azepine-5-carboxamide (BIA 2-093) and 10, 11-dihydro-10-hydroxyimino-5H-dibenz[b,f]azepine-5-carboxamide (BIA 2-024), and compared their effects with the established compounds carbamazepine and oxcarbazepine. The assessment of neuronal injury was made by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl (MTT) assay, as well as by analysing morphology and nuclear chromatin condensation (propidium iodide staining), after hippocampal neurons were exposed to the drugs for 24 h. The putative antiepileptic drugs, BIA 2-093 or BIA 2-024 (at 300 microM), only slightly decreased MTT reduction, whereas carbamazepine or oxcarbazepine were much more toxic at lower concentrations. Treatment with the antiepileptic drugs caused nuclear chromatin condensation in some neurons, which is characteristic of apoptosis, and increased the activity of caspase-3-like enzymes, mainly in neurons treated with carbamazepine and oxcarbazepine. The toxic effect caused by carbamazepine was not mediated by N-methyl-D-aspartate (NMDA) or by alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionate (AMPA) receptors. Moreover, the antiepileptic drugs failed to protect hippocampal neurons from the toxicity caused by kainate, veratridine, or ischaemia-like conditions.

Nocturnal sleep quality and circadian blood pressure variation

OBJECTIVE

To verify whether non-dipper behavior is associated with poor nocturnal sleep quality and a higher rate of obstructive sleep apnea than dipper behavior.

METHODS

A sample of 36 subjects older than 50 years (mean age = 70 +/- 6.49 years), 8 males and 28 females, 27 (75%) hypertensive and 9 (25%) normotensive, was studied. Nocturnal polysomnography was carried out in the patients' homes. 24-hour ambulatory blood pressure was studied with Spacelabs 90,207 device. The statistical tests used were Student's t test, Pearson's correlation and the Chi-square test.

RESULTS

In the overall sample, higher rates of apnea, higher rates of arousal and shorter duration of the REM (rapid eye movement) phase were linked to high levels of nocturnal diastolic blood pressure, with statistical significance (p < 0.01, p < 0.01, p < 0.05 respectively). Sleep fragmentation was associated with the lowest percentages of variation in daytime to nighttime systolic blood pressure (p < 0.03). Apnea rates were significantly higher in the hypertensive group compared to the normal blood pressure population (p = 0.04). We also observed that higher rates of nocturnal apnea corresponded to lower variations in daytime to nighttime systolic blood pressure (p = 0.015) and to a lower dipper index (p < 0.05). Higher indexes of arousal and lower REM latency were associated with higher nocturnal blood pressure, both systolic (p = 0.039 and p = 0.008, respectively) and diastolic (p = 0.003 and p = 0.029, respectively). Sleep efficiency was also negatively correlated with mean levels of nocturnal diastolic blood pressure (p = 0.038).

CONCLUSIONS

The quality of nocturnal sleep seems to play an important role in blood pressure levels, particularly in the nocturnal blood pressure profile. A poor quality of nocturnal sleep and the rate of obstructive sleep apnea were associated with non-dipper behavior in the hypertensive population. Sleep evaluation is particularly useful in non-dipper subjects with hypertension.