XAIRE: An ensemble-based methodology for determining the relative importance of variables in regression tasks. Application to a hospital emergency department

Nowadays it is increasingly important in many applications to understand how different factors influence a variable of interest in a predictive modeling process. This task becomes particularly important in the context of Explainable Artificial Intelligence. Knowing the relative impact of each variable on the output allows us to acquire more information about the problem and about the output provided by a model. This paper proposes a new methodology, XAIRE, that determines the relative importance of input variables in a prediction environment, considering multiple prediction models in order to increase generality and avoid bias inherent in a particular learning algorithm. Concretely, we present an ensemble-based methodology that promotes the aggregation of results from several prediction methods to obtain a relative importance ranking. Also, statistical tests are considered in the methodology in order to reveal significant differences between the relative importance of the predictor variables. As a case study, XAIRE is applied to the arrival of patients in a Hospital Emergency Department, which has resulted in one of the largest sets of different predictor variables in the literature. Results show the extracted knowledge related to the relative importance of the predictors involved in the case study.

Resonance Excitations in ^{7}Be(d,p)^{8}Be^{*} to Address the Cosmological Lithium Problem

The anomaly in lithium abundance is a well-known unresolved problem in nuclear astrophysics. A recent revisit to the problem tried the avenue of resonance enhancement to account for the primordial ^{7}Li abundance in standard big-bang nucleosynthesis. Prior measurements of the ^{7}Be(d,p)^{8}Be^{*} reaction could not account for the individual contributions of the different excited states involved, particularly at higher energies close to the Q value of the reaction. We carried out an experiment at HIE-ISOLDE, CERN to study this reaction at E_{c.m.}=7.8  MeV, populating excitations up to 22 MeV in ^{8}Be for the first time. The angular distributions of the several excited states have been measured and the contributions of the higher excited states in the total cross section at the relevant big-bang energies were obtained by extrapolation to the Gamow window using the talys code. The results show that by including the contribution of the 16.63 MeV state, the maximum value of the total S factor inside the Gamow window comes out to be 167 MeV b as compared to earlier estimate of 100 MeV b. However, this still does not account for the lithium discrepancy.

A prototype of pCT scanner: first tests

Proton therapy technique for cancer treatment offers a high selectivity with respect to conventional radiotherapy with X- and γ-rays due to the properties of the interaction of protons with matter. Very accurate and precise treatment plans and a good control on the dose deposition are required to exploit the full potential of the technique. The substitution of the currently used X-ray Computed Tomography (xCT) by proton Computed Tomography (pCT) in the design of treatment plans would allow for a reduction in proton range uncertainties. This would make possible an important improvement in the accuracy and precision of treatment plans. With this aim, a prototype of pCT scanner is under study. It includes two tracking detectors which provide information on the proton trajectories and a residual energy detector to determine the energy loss while traversing the object scanned. A proof-of-concept experiment has been performed using low-energy protons and a simplified prototype with only the two tracking detectors. The results obtained in the measurement are presented and discussed.

Competition between Allowed and First-Forbidden β Decay: The Case of ^{208}Hg→^{208}Tl

The β decay of ^{208}Hg into the one-proton hole, one neutron-particle _{81}^{208}Tl_{127} nucleus was investigated at CERN-ISOLDE. Shell-model calculations describe well the level scheme deduced, validating the proton-neutron interactions used, with implications for the whole of the N>126, Z<82 quadrant of neutron-rich nuclei. While both negative and positive parity states with spin 0 and 1 are expected within the Q_{β} window, only three negative parity states are populated directly in the β decay. The data provide a unique test of the competition between allowed Gamow-Teller and Fermi, and first-forbidden β decays, essential for the understanding of the nucleosynthesis of heavy nuclei in the rapid neutron capture process. Furthermore, the observation of the parity changing 0^{+}→0^{-}β decay where the daughter state is core excited is unique, and can provide information on mesonic corrections of effective operators.

First Accurate Normalization of the β-delayed α Decay of ^{16}N and Implications for the ^{12}C(α,γ)^{16}O Astrophysical Reaction Rate

The ^{12}C(α,γ)^{16}O reaction plays a central role in astrophysics, but its cross section at energies relevant for astrophysical applications is only poorly constrained by laboratory data. The reduced α width, γ_{11}, of the bound 1^{-} level in ^{16}O is particularly important to determine the cross section. The magnitude of γ_{11} is determined via sub-Coulomb α-transfer reactions or the β-delayed α decay of ^{16}N, but the latter approach is presently hampered by the lack of sufficiently precise data on the β-decay branching ratios. Here we report improved branching ratios for the bound 1^{-} level [b_{β,11}=(5.02±0.10)×10^{-2}] and for β-delayed α emission [b_{βα}=(1.59±0.06)×10^{-5}]. Our value for b_{βα} is 33% larger than previously held, leading to a substantial increase in γ_{11}. Our revised value for γ_{11} is in good agreement with the value obtained in α-transfer studies and the weighted average of the two gives a robust and precise determination of γ_{11}, which provides significantly improved constraints on the ^{12}C(α,γ) cross section in the energy range relevant to hydrostatic He burning.

Strong Neutron Pairing in core+4n Nuclei

The emission of neutron pairs from the neutron-rich N=12 isotones ^{18}C and ^{20}O has been studied by high-energy nucleon knockout from ^{19}N and ^{21}O secondary beams, populating unbound states of the two isotones up to 15 MeV above their two-neutron emission thresholds. The analysis of triple fragment-n-n correlations shows that the decay ^{19}N(-1p)^{18}C^{*}→^{16}C+n+n is clearly dominated by direct pair emission. The two-neutron correlation strength, the largest ever observed, suggests the predominance of a ^{14}C core surrounded by four valence neutrons arranged in strongly correlated pairs. On the other hand, a significant competition of a sequential branch is found in the decay ^{21}O(-1n)^{20}O^{*}→^{18}O+n+n, attributed to its formation through the knockout of a deeply bound neutron that breaks the ^{16}O core and reduces the number of pairs.

Quasifree (p, 2p) Reactions on Oxygen Isotopes: Observation of Isospin Independence of the Reduced Single-Particle Strength

Quasifree one-proton knockout reactions have been employed in inverse kinematics for a systematic study of the structure of stable and exotic oxygen isotopes at the R^{3}B/LAND setup with incident beam energies in the range of 300-450  MeV/u. The oxygen isotopic chain offers a large variation of separation energies that allows for a quantitative understanding of single-particle strength with changing isospin asymmetry. Quasifree knockout reactions provide a complementary approach to intermediate-energy one-nucleon removal reactions. Inclusive cross sections for quasifree knockout reactions of the type ^{A}O(p,2p)^{A-1}N have been determined and compared to calculations based on the eikonal reaction theory. The reduction factors for the single-particle strength with respect to the independent-particle model were obtained and compared to state-of-the-art ab initio predictions. The results do not show any significant dependence on proton-neutron asymmetry.

Scattering of the Halo Nucleus ^{11}Be on ^{197}Au at Energies around the Coulomb Barrier

Angular distributions of the elastic, inelastic, and breakup cross sections of the halo nucleus ^{11}Be on ^{197}Au were measured at energies below (E_{lab}=31.9  MeV) and around (39.6 MeV) the Coulomb barrier. These three channels were unambiguously separated for the first time for reactions of ^{11}Be on a high-Z target at low energies. The experiment was performed at TRIUMF (Vancouver, Canada). The differential cross sections were compared with three different calculations: semiclassical, inert-core continuum-coupled-channels and continuum-coupled-channels ones with including core deformation. These results show conclusively that the elastic and inelastic differential cross sections can only be accounted for if core-excited admixtures are taken into account. The cross sections for these channels strongly depend on the B(E1) distribution in ^{11}Be, and the reaction mechanism is sensitive to the entanglement of core and halo degrees of freedom in ^{11}Be.

First observation of the unbound nucleus 15Ne

We report on the first observation of the unbound proton-rich nucleus 15Ne. Its ground state and first excited state were populated in two-neutron knockout reactions from a beam of 500 MeV/u 17Ne. The 15Ne ground state is found to be unbound by 2.522(66) MeV. The decay proceeds directly to 13O with simultaneous two-proton emission. No evidence for sequential decay via the energetically allowed 2- and 1- states in 14F is observed. The 15Ne ground state is shown to have a strong configuration with two protons in the (sd) shell around 13O with a 63(5)% (1s1/2)2 component.

Precise determination of the unperturbed 8B neutrino spectrum

A measurement of the final state distribution of the (8)B β decay, obtained by implanting a (8)B beam in a double-sided silicon strip detector, is reported here. The present spectrum is consistent with a recent independent precise measurement performed by our collaboration at the IGISOL facility, Jyväskylä [O. S. Kirsebom et al., Phys. Rev. C 83, 065802 (2011)]. It shows discrepancies with previously measured spectra, leading to differences in the derived neutrino spectrum. Thanks to a low detection threshold, the neutrino spectrum is for the first time directly extracted from the measured final state distribution, thus avoiding the uncertainties related to the extrapolation of R-matrix fits. Combined with the IGISOL data, this leads to an improvement of the overall errors and the extension of the neutrino spectrum at high energy. The new unperturbed neutrino spectrum represents a benchmark for future measurements of the solar neutrino flux as a function of energy.

Abortion associated with Chlamydia abortus in extensively reared Iberian sows

Reproductive disease was investigated in Iberian pigs on an extensive farrow-to-finish farm in the southwest of Spain. Chlamydia abortus was isolated in cell culture and C. abortus-specific PCR products were detected in placental and fetal tissues. In one batch of 14 sows, the percentage of sera positive for C. abortus specific antibodies increased from 35.7% to 85.7% in the period of 2 weeks following abortion. C. abortus may play a role in abortion in extensively reared Iberian sows.

Seroprevalence of Toxoplasma gondii in equids from Southern Spain

Antibodies to Toxoplasma gondii were determined in serum samples from 616 equids (454 horses, 80 mules and 82 donkeys) in a cross-sectional study of 420 herds in Andalusia (Southern Spain), the region with the highest number of equids in Spain. Antibodies to T. gondii were found in 10.8% horses, 15.0% mules and 25.6% donkeys by using the modified agglutination test (MAT) at a cut-off of 1:25. Herd seroprevalence for horses, mules and donkeys was 14.7% (48/327), 23.9% (11/46) and 34.0% (16/47), respectively, and 75 herds (17.8%) had at least one seropositive animal. Significant differences in T. gondii seroprevalence were observed among species, with donkeys having the highest seroprevalence and horses the lowest (P=0.04). Seroprevalence was significantly higher in herds with presence of domestic ruminants. This study is the first report of the presence of T. gondii antibodies in equine species in Spain and the first reporting T. gondii infection in donkeys in Europe. The presence of antibodies is indication of contact with the parasite and therefore, consumption of equine meat could be a potential source of human infection in Spain.

Factores de riesgo del Síndrome respiratorio bovino en terneros lactantes de Argentina

Se ha realizado un estudio epidemiológico observacional de tipo transversal para conocer los factores que actúan sobre la seropositividad de los principales agentes víricos del síndrome respiratorio bovino: el herpesvirus bovino tipo 1 (HVB1), el virus de la diarrea vírica bovina (VDVB), el virus respiratorio sincitial bovino (VRSB) y el virus de la parainfluenza 3 (VPI3). Se tomaron muestras de sangre de terneros procedentes de explotaciones lecheras situadas en las provincias argentinas de Córdoba y Santa Fé, y se cumplimentaron cuestionarios epide-miológicos. Los análisis serológicos se realizaron mediante la técnica ELISA. En total se tomaron muestras de sangre de 852 terneros procedentes de 55 explotaciones entre los años 2000 y 2002. Se realizaron cuatro modelos epidemiológicos mediante regresión logística, uno por cada virus donde, entre otras, aparecen variables asociadas a la infección relacionadas con la edad del ternero, la estación del año, el número de animales, la alimentación, las vacunaciones o el sistema de crianza.

Epidemiological tracing of Salmonella enterica serotype Abortusovis from Spanish ovine flocks by PFGE fingerprinting

Salmonella enterica serotype Abortusovis, an ovine host-specific serotype, rare in most countries, is responsible for epidemic abortion episodes in Spain. With the aim of surveillance and detection of the spread of specific clones, 55 Abortusovis isolates collected during 1996-2001 from flocks in 11 provinces, were studied using XbaI-PFGE. Despite the fact that the strains were geographically and spatially related, PFGE demonstrated an epidemiologically acceptable discriminating power, identifying 20 clones (similarity, 52-96%). Clones Sabv6, 1, 5 were disseminated in seven, five and two areas respectively, while another 17 clones appeared in single places. Clones from nearby geographic regions showed a high relatedness (one band of difference in the PFGE profile) Sabv1-2-3, Sabv5-6, Sabv7-8, and Sabv13-14, suggesting a common ancestor. Co-isolation in the same flock (Sabv5-6, Sabv1-3, Sabv1-6) was detected. PFGE surveillance detected the predominance and widespread distribution of clone Sabv6 in 21 out of the 55 Abortusovis serotype episodes studied in Spain.

Temporally and spectrally resolved imaging of laser-induced plasmas

We report a hybrid imaging technique capable of performing measurements of the spatial, temporal, and spectral emission characteristics of laser-induced plasmas by use of a single detection system. We apply this technique to study the plasma produced by laser ablation of LiNbO3 and observe phenomena not seen in such detail with standard instruments. These include extreme line broadening up to a few nanometers accompanied by self-absorption near the target surface, and expansion dynamics that differ strongly between the different species. Overall, the wealth of quantitative information provided by this novel technique sheds new light on processes occurring during plasma expansion.

Comparison of diagnostic techniques for porcine proliferative enteropathy (Lawsonia intracellularis infection)

In studying the post-mortem diagnosis of porcine proliferative enteropathy (PPE) a "double-blind" study was performed on 77 apparently healthy "finisher" pigs at the time of slaughter, to compare the results of a polymerase chain reaction (PCR) technique with those of (1) an indirect immunofluorescence assay (IFA), (2) examination for gross proliferative lesions at slaughter, (3) histopathological study of sections stained with haematoxylin and eosin (HE), and (4) Warthin-Starry (WS) silver staining for intracellular bacteria. The IFA, with a sensitivity of 89% and a specificity of 97% (positive "likelihood ratio"=30) and an agreement of 82% with PCR, is suggested as an alternative to the PCR in the post-mortem diagnosis of PPE. Histopathological examination was shown to be of little use as a principal diagnostic method, although it appeared to be effective in diagnosing infection by Lawsonia intracellularis in cases with proliferative-type lesions (positive likelihood ratio=29.6). Finally, the values obtained from an examination of gross lesions (k=0.075; positive likelihood ratio of 1.3) and WS staining (k=0.42; positive likelihood ratio of 5.3) demonstrated the lack of validity of these tests for the diagnosis of L. intracellularis infection.

Coinfection by Cryptosporidium parvum and porcine circovirus type 2 in weaned pigs

Routine histopathological diagnosis of one representative 3-month-old pig from a group suffering from diarrhoea revealed a massive degree of parasitation by Cryptosporidium parvum, with a concomitant infection by porcine circovirus type 2 (PCV2), that was confirmed by immunohistochemical procedures. The areas of intestine where parasites were more numerous presented abundant PCV2 infected cells in mucosa and submucosa. The concurrence of C. parvum, a rare primary intestinal pathogen in post-weaning and growing pigs, and PCV2 infections suggest an increased susceptibility as a result of an immunosuppression state.

Epidemiological relationship of human and swine Streptococcus suis isolates

Two cases of meningitis due to Streptococcus suis in humans are reported here. A butcher and an abattoir worker were referred to a health centre in Castellón (Spain) with fever and symptoms of meningitis. After adequate treatment, a slight hipoacusia persisted as sequelae in both cases. Colonies of S. suis group R, serotype 2 and phenotype MRP+EF+ were isolated from cerebroespinal fluid. Epidemiological studies showed that both workers had in common the handling of pork meat of slaughtered healthy pigs from three closed farms. A study of the tonsils from apparently healthy, slaughtered pigs was carried out. A total of 234 tonsillar samples were obtained and 81 strains of S. suis were isolated from them. Serotype 2 appeared to be the most frequent (50.6%), and the analysis for phenotype showed a high percentage of tonsillar strains with the phenotype MRP+EF+ (35.9%). The humans and 28 tonsillar swine strains showed a similar profile (S. suis group R, serotype 2 and phenotype MRP+EF+). A total of 26 of the swine isolates were analysed by ribotyping using EcoRI. The human strains showed the same six-band hybridization pattern that shared five bands with the pattern most frequently shown by most of the tonsillar N. suis group R, serotype 2 and phenotype MRP+EF+ strains, differing only in the lightest, faintest band which was slightly less anodical in human (> or = 1.8 kb) than in swine (approximately 1.8 kb). From these results, both groups of strains, humans and porcine, showed differences; how can these differences in the pattern of ribotyping be explained if they should have the same origin? Is it possible that they have undergone an adaptation to the new host or perhaps the modification is due to other unknown causes? Further studies in this area are required in order to answer these questions.

Effectiveness of doxycycline in the prevention of an experimental infection with Actinobacillus pleuropneumoniae in pigs

The effectiveness of medication with doxycycline in feed in the control of pleuropneumonia in pigs was tested using an Actinobacillus pleuropneumoniae serotype 1 aerosol challenge model. Two groups of 10 animals were used for the challenge, a 'medicated group' and an 'unmedicated group'. A third group of four animals was used as a 'control group'. Pigs from the medicated group were provided with feed containing 250 p.p.m. doxycycline (HIPRAMIX/DOXI) for 8 consecutive days and were challenged on the fifth day of treatment. No clinical signs were observed in pigs from the 'control group'. Four animals from the 'unmedicated group' died within the first 48 h after challenge with clinical and lesional evidence of an acute form of pleuropneumonia. Clinical signs of animals surviving the first 48 h were progressively less severe and showed lesions similar to those described for subacute-chronic forms of the disease. However, only one animal from the 'medicated group' showed clinical signs of a chronic form of pleuropneumonia. Reisolation of A. pleuropneumoniae was more evident from lung tissues of animals fed the doxycycline-free feed (70%), coinciding with the presence of both acute and subacute lesions. However, the micro-organism could be reisolated from only one animal which belonged to the 'medicated group'. It is concluded that the treatment of pigs with 250 p.p.m. doxycycline (HIPRAMIX/DOXI) prevents disease caused by A. pleuropneumoniae.

Power distance and collectivist/individualist strategies in alcohol warnings: effects by gender and ethnicity

This research examined the responses of 73 Mexican American and Anglo young adults to four televised drinking-and-driving warnings. Warnings were manipulated into collectivist (emphasizing risks to family and friends) and individualist (emphasizing risks to self) appeals, and into high and low power distance appeals by attributing or not attributing warnings to the Surgeon General. Females rated the collectivist warnings, and males the individualist warnings, more believable. Respondents on average responded to the collectivist warnings most positively, regardless of gender or ethnicity. Anglos rated warnings without the Surgeon General as the source more believable than warnings with the Surgeon General as the source; the opposite was true for Latinos. Other interactions were also found.

The presence of muramidase released protein and extracellular factor protein in various serotypes of Streptococcus suis isolated from diseased and healthy pigs in Spain

A total of 142 strains from different serotypes of Streptococcus suis isolated in Spain from diseased pigs (88 strains) and healthy carrier pigs (54 strains) were studied for the presence of a muramidase released protein (MRP) and an extracellular factor (EF). The following five phenotypes: MRP+EF+, MRP+EF-, MRP-EF+, MRP+EF* and MRP*EF- were detected. A high percentage of S. suis serotype 2 strains isolated from diseased pigs (84 per cent) belonged to phenotype MRP+EF+, but this phenotype has also been noticed in other serotypes (serotypes 1, 1/2 and 14). Both proteins were detected in S. suis serotype 2 strains (26%) isolated from healthy carrier pigs and one of both proteins in serotypes 1 and 14 (phenotype MRP+EF*). The isolation of S. suis strains from healthy pigs which have shown both proteins may support the epidemiological significance of these carriers in the maintenance, transmission and distribution of virulent strains within and between swine farms.

GLP-1 (7-36) amide: effects on glucose transport and metabolism in rat adipose tissue

In rat adipocytes, GLP-1 (7-36) amide induced an increment in 2-deoxy-glucose uptake, which was additive to that of insulin. Furthermore, in rat fat, GLP-1 (7-36) amide provoked a rise in glycogen synthesis, glucose oxidation and utilization and lipogenesis, the increments being lower than those obtained with insulin. These data support the idea that GLP-1 exerts insulin-like effects on glucose metabolism in rat adipose tissue, as it does in rat hepatocytes and skeletal muscle, although with a lower potency than that of insulin.

Pneumonic pasteurellosis associated with Pasteurella haemolytica in chipmunks (Tamias sibiricus)

A laboratory study was performed in order to identify the possible cause of death in chipmunks (Tamias sibiricus) imported from China with respiratory disease. Severe congestion, alveolar oedema and fibrinous pleuritis were observed. Biochemical analyses identified the causative organism as Pasteurella haemolytica. An in vitro susceptibility test using various antimicrobial agents revealed sensitivity to beta-lactams (ampicillin and amoxicillin) and streptomycin.

Inositolphosphoglycans and diacyglycerol are possible mediators in the glycogenic effect of GLP-1(7-36)amide in BC3H-1 myocytes

A potent glycogenic effect of GLP-1(7-36)amide has been found in rat hepatocytes and skeletal muscle, and specific receptors for this peptide, which do not seem to be associated with the adenylate cyclase-cAMP system, have been detected in these tissue membranes. On the other hand, inositolphosphoglycan molecules (IPGs) have been implicated as second messengers of the action of insulin. In this work, we have found, in differentiated BC3H-1 myocytes, specific binding of [125I]GLP-1(7-36)amide, and a stimulatory effect of the peptide on glycogen synthesis, confirming the findings in rat skeletal muscle. Also, GLP-1(7-36)amide modulates the cell content of radiolabelled glycosylphosphatidylinositols (GPIs) and increases the production of diacylglycerol (DAG), in the same manner as insulin acts, indicating hydrolysis of GPIs and an immediate and short-lived generation of IPGs. Thus, IPGs and DAG could be mediators in the glycogenic action of GLP-1(7-36)amide in skeletal muscle.

Physiological effect of glucagon in human isolated adipocytes

In human isolated adipocytes, glucagon induces a dose dependent increment of the glycerol release, which is already observed at physiological concentrations of the hormone. Furthermore, glucagon at 10(-8) M, significantly stimulates the adenylate cyclase activity in both non-solubilized and solubilized fat plasma membranes, and at already 10(-11) M, a significant increment of the adipocyte cAMP content is observed. These data support previous in vivo positive results indicating that glucagon plays a role in human fat metabolism.

Glucagon-like peptide-1 binding to rat hepatic membranes

We have found [125I]glucagon-like peptide (GLP)-1(7-36)amide specific binding activity in rat liver and isolated hepatocyte plasma membranes, with an M(r) of approximately 63,000, estimated by cross-linking and SDS-PAGE. The specific binding was time- and membrane protein concentration-dependent, and equally displaced by unlabelled GLP-1(7-36)amide and by GLP-1(1-36)amide, achieving its ID50 at 3 x 10(-9) M of the peptides. GLP-1(7-36)amide did not modify the basal or the glucagon (10(-8) M)-stimulated adenylate cyclase in the hepatocyte plasma membranes. These data, together with our previous findings of a potent glycogenic effect of GLP-1(7-36)amide in isolated rat hepatocytes, led us to postulate that the insulin-like effects of this peptide on glucose liver metabolism could be mediated by a type of receptor probably different from that described for GLP-1 in pancreatic B-cells or, alternatively, by the same receptor which, in this tissue as well as in muscle, uses a different transduction system.

Susceptibility of Streptococcus suis to various antimicrobial agents

A study was performed to determine the susceptibility of 59 S. suis strains, isolated from sick and healthy carrier swine, to a range of antimicrobial agents. The beta-lactamic group proved more active both in Kirby-Bauer and MCI tests. Trimethoprim-sulfamethoxazole emerged as an alternative drug in chemoprevention and treatment of S. suis infections.

Prevalence of antibodies to different Leptospira interrogans serovars in pigs on large farms

A seroepidemiological survey was carried out in the province of Badajoz (south-western Spain) in order to determine the presence and spread of Leptospira interrogans. The 521 sera tested were drawn from breeding sows on 28 large farms (15 with fewer than 60 and 13 with over 60 breeders). Immunological testing was performed using the Martin-Pettit micro-agglutination technique. Pigs with titres equal to or greater than 1:100 were considered positive. Haemolysed and/or contaminated test sera were reprocessed following filter-paper treatment. A total of 10.56% of pigs tested proved positive, 39.28% of farms being affected. The following L. interrogans serovars were detected: pomona (6.53%), castellonis (1.15%), sejroe (1.15%), grippotyphosa (0.96%), australis (0.38%), hebdomadis (0.19%) and icterohaemorrhagiae (0.19%).

Short-term feeding of a diet enriched in phospholipids increases bile formation and the bile acid transport maximum in rats

Earlier studies suggested that the secretory rate maximum (SRm) of bile acid and the cholestasis which occurs after the SRm is reached may be determined by the hepatic or extrahepatic biliary phospholipid pool. We therefore investigated whether bile formation and the bile acid SRm could be influenced by feeding a diet enriched in phospholipids. Male rats were fed phospholipid (PLD) or triacylglycerol (TgD)-enriched diet for 3 days, and bile formation as well as biliary lipid output were measured on the 4th day. In other similarly fed groups, cholic acid was infused in stepwise increasing doses to determine the effect of PLD on the SRm of cholic acid. The plasma lipid levels were significantly lower in PLD and TgD diets compared to basal diet. But, while the levels of total cholesterol (CH), HDL-CH, and phospholipid (PH) were not significantly altered by PLD compared to TgD, the triacylglycerol levels were markedly increased by PLD. In the liver of PLD fed rats, triacylglycerol and CH ester contents decreased by 39 and 62%, respectively, while free CH and PH contents were not significantly changed. The PLD significantly augmented spontaneous bile flow, bile acid, PH and CH secretion rates compared to TgD diet (65, 124, 164 and 654%, respectively). The enhanced biliary secretory function was associated with an increase in pericanalicular vacuoles and diverticuli in centrilobular hepatocytes. Compared to TgD fed rats, PLD rats showed a 2-fold decrease in the ratio of cholic acid/chenodeoxycholic acid in bile and a significant decrease in the % contribution of taurine conjugated BA. The PH fatty acids in bile were similar in both groups except that in PLD group the % contribution of C18:2 was higher than in TgD group. No differences were found in plasma membrane CH/PH content or total fatty acid composition. During bile acid infusion, the SRm and the total cholic acid secreted were significantly higher in the PLD than in the TgD rats. Moreover, the cholestatic response observed after high bile acid dose was markedly reduced by PLD. The results show that short-term feeding of PLD induces changes in CH and bile acid metabolism which result in enhanced biliary output of CH and PH. The enhanced pool of biliary lipid may protect plasma membranes from the deleterious effects of high bile acid concentrations.

Moderate long-term physical activity improves the age-related decline in bile formation and bile salt secretion in rats

This study examined the effect of moderate long-term exercise, begun soon after weaning, on the age-related decline in bile formation and the secretory rate maximum (SRm) of taurocholate (TC), the major bile salt (BS) in rats. Eight-month-old sedentary (S) female Sprague-Dawley rats showed a significant decrease in basal and TC-stimulated bile formation when compared with 2.5-month-old S controls. As in younger rats, decreased biliary phospholipid (PL) output was associated with the TC SRm, but this change appeared much more rapidly in S animals, which also exhibited significant increased plasma lipids and higher TC concentrations in plasma and liver at the end of the TC infusion. Exercise significantly improved bile flow (BF), including the bile salt-dependent and -independent fractions under basal and TC-stimulated conditions in 8 month-old rats. Although all the biliary parameters evaluated were improved, maximal BF and PL secretion values were affected the most and were virtually not different from those obtained in younger S animals. Exercise also significantly lowered the age-related elevation of plasma PL. Thus, moderate long-term exercise exerts a beneficial effect on hepatobiliary function and the BS SRm, an effect that may be attributed in part to increased availability of a biliary PL pool previously implicated in regulation of the BS SRm.

Glucagon-like peptide 1: a potent glycogenic hormone

GLP-1(7-36)amide is an insulinotropic peptide derived from the intestinal post-translational proglucagon process, the release of which is increased mainly after a carbohydrate meal; also, its anti-diabetogenic effect in normal and diabetic states has been reported. In this study, GLP-1(7-36)amide stimulates the formation of glycogen from glucose in isolated rat hepatocytes, such a glycogenic effect being achieved with physiological concentrations of the peptide. The GLP-1(7-36)amide-induced glycogenesis is abolished by glucagon, and it is accompanied by stimulation of the glycogen synthase alpha activity and by a decrease in the basal and glucagon-stimulated cyclic AMP content. These findings could explain, at least in part, the GLP-1(7-36)amide insulin-independent plasma glucose lowering effect.

Serological survey of infections in waterfowl in the Guadalquivir marshes (Spain)

A serological survey was performed in the Guadalquivir Marshes (Southern Spain) in order to determine the presence and diffusion of six infective agents in wild waterfowl. The analysis covered 712 waterfowl from 13 species belonging to five taxa (Podicipediformes, Ciconiiformes, Anseriformes, Gruiformes, and Charadriiformes). A range of immunological techniques led to detection of antibodies against the six infective agents studied: Chlamydia psittaci (13.3%), Mycoplasma anatis (3.5%), Pasteurella anatipestifer (2.9%), duck plague virus (1.6%), Aspergillus fumigatus (1.1%), and Newcastle disease virus (NDV) (0.2%). The survey results indicated that these infective agents exist and circulate among wild waterfowl in the Guadalquivir Marshes.